View source for Engineering:Glossary of engineering

{{short description|List of definitions of terms and concepts commonly used in the study of engineering}}
This '''glossary of engineering terms''' is a list of definitions about the major concepts of '''[[Engineering:Engineering|engineering]]'''. Please see the bottom of the page for glossaries of specific fields of engineering.



== A ==
{{glossary}}
{{term|term= '''[[Chemistry:Absolute electrode potential|Absolute electrode potential]]'''}}{{defn|defn=In [[Chemistry:Electrochemistry|electrochemistry]], according to an IUPAC definition,<ref>[http://goldbook.iupac.org/A00022.html IUPAC Gold Book - absolute electrode potential<!-- Bot generated title -->]</ref> is the [[Chemistry:Electrode potential|electrode potential]] of a [[Chemistry:Metal|metal]] measured with respect to a universal reference system (without any additional metal–solution interface).}} 
{{term|term= '''Absolute pressure'''}}{{defn|defn=Is zero-referenced against a perfect vacuum, using an [[Absolute scale|absolute scale]], so it is equal to gauge pressure plus atmospheric pressure.}} 
{{term|term= '''[[Physics:Absolute zero|Absolute zero]]'''}}{{defn|defn=Is the lower limit of the [[Physics:Thermodynamic temperature|thermodynamic temperature]] scale, a state at which the [[Physics:Enthalpy|enthalpy]] and [[Physics:Entropy|entropy]] of a cooled [[Physics:Ideal gas|ideal gas]] reach their minimum value, taken as 0. Absolute zero is the point at which the fundamental particles of nature have minimal vibrational motion, retaining only quantum mechanical, [[Physics:Zero-point energy|zero-point energy]]-induced particle motion. The theoretical temperature is determined by extrapolating the [[Physics:Ideal gas law|ideal gas law]]; by international agreement, absolute zero is taken as −273.15° on the [[Celsius]] scale ([[International System of Units]]),<ref name=sib2115>{{cite web|title=Unit of thermodynamic temperature (kelvin) |work=SI Brochure, 8th edition |at=Section 2.1.1.5 |url=http://www.bipm.org/en/publications/si-brochure/kelvin.html |publisher=Bureau International des Poids et Mesures |date=13 March 2010 |orig-year=1967 |access-date=20 June 2017 |url-status=dead |archive-url=https://web.archive.org/web/20141007053944/http://www.bipm.org/en/publications/si-brochure/kelvin.html |archive-date=7 October 2014 }} '''Note''': The triple point of water is 0.01 °C, not 0 °C; thus 0 K is −273.15 °C, not −273.16 °C.</ref><ref name="arora">{{cite book|title=Thermodynamics|first1=C. P.|last1=Arora|publisher=Tata McGraw-Hill |year=2001|isbn=978-0-07-462014-4|at=Table 2.4 page 43|url=https://books.google.com/books?id=w8GhW3J8RHIC&pg=PA43}}</ref> which equals −459.67° on the [[Fahrenheit]] scale (United States customary units or [[Imperial units]]).<ref>{{Cite web |url=http://www.smithsonianmag.com/science-nature/absolute-zero-200801.html|last1=Zielinski|first1=Sarah|date=1 January 2008|title=Absolute Zero|publisher=Smithsonian Institution|access-date=2012-01-26}}</ref> The corresponding [[Kelvin]] and [[Physics:Rankine scale|Rankine]] temperature scales set their zero points at absolute zero by definition.
}}
{{term|term= '''[[Physics:Absorbance|Absorbance]]'''}}{{defn|defn=Absorbance or ''decadic absorbance'' is the ''[[Common logarithm|common logarithm]]'' of the ratio of incident to ''transmitted'' radiant power through a material, and ''spectral absorbance'' or ''spectral decadic absorbance'' is the common logarithm of the ratio of incident to ''transmitted'' spectral radiant power through a material.<ref name=GoldBook>{{GoldBookRef|title=Absorbance|file=A00028|accessdate=2015-03-15}}</ref>}} 
{{term|term= '''[[Physics:AC power|AC power]]'''}}{{defn|defn= Electric power delivered by alternating current; common household power is AC.}}
{{term|term= '''[[Physics:Acceleration|Acceleration]]'''}}{{defn|defn= The rate at which the velocity of a body changes with time, and the direction in which that change is acting.}} 
{{term|term= '''[[Chemistry:Acid|Acid]]'''}}{{defn|defn=A [[Physics:Molecule|molecule]] or [[Physics:Ion|ion]] capable of donating a [[Chemistry:Hydron|hydron]] (proton or hydrogen ion H<sup>+</sup>), or, alternatively, capable of forming a [[Chemistry:Covalent bond|covalent bond]] with an [[Physics:Electron pair|electron pair]] (a Lewis acid).<ref name="IUPAC_acid">[http://goldbook.iupac.org/A00071.html IUPAC Gold Book - acid]</ref>}} 
{{term|term= '''[[Chemistry:Acid–base reaction|Acid–base reaction]]'''}}{{defn|defn=A chemical reaction that occurs between an acid and a base, which can be used to determine pH. }} 
{{term|term= '''[[Chemistry:Acid strength|Acid strength]]'''}}{{defn|defn=In strong acids, most of the molecules give up a hydrogen ion and become ionized.}}
{{term|term= '''[[Physics:Acoustics|Acoustics]]'''}}{{defn|defn=The scientific study of sound.}} 
{{term|term= '''[[Chemistry:Activated sludge|Activated sludge]]'''}}{{defn|defn= A type of wastewater treatment process for treating sewage or industrial wastewaters using aeration and a biological floc composed of bacteria and protozoa.}}
{{term|term= '''[[Engineering:Activated sludge model|Activated sludge model]]'''}}{{defn|defn=A generic name for a group of mathematical methods to model activated sludge systems.}} 
{{term|term= '''[[Biology:Active transport|Active transport]]'''}}{{defn|defn=In cellular biology, active transport is the movement of molecules across a membrane from a region of their lower concentration to a region of their higher concentration—against the concentration gradient. Active transport requires cellular energy to achieve this movement. There are two types of active transport: ''primary active transport'' that uses [[Chemistry:Adenosine triphosphate|ATP]], and ''secondary active transport'' that uses an electrochemical gradient. An example of active transport in human physiology is the uptake of [[Chemistry:Glucose|glucose]] in the [[Biology:Gastrointestinal tract|intestines]].}} 
{{term|term= '''[[Engineering:Actuator|Actuator]]'''}}{{defn|defn=A device that accepts 2 inputs (control signal, energy source) and outputs kinetic energy in the form of physical movement (linear, rotary, or oscillatory). The control signal input specifies which motion should be taken. The energy source input is typically either an electric current, hydraulic pressure, or pneumatic pressure. An actuator can be the final element of a control loop}} 
{{term|term= '''[[Chemistry:Adenosine triphosphate|Adenosine triphosphate]]'''}}{{defn|defn=A complex [[Chemistry:Organic compound|organic chemical]] that provides energy to drive many processes in living [[Biology:Cell|cells]], e.g. muscle contraction, nerve impulse propagation, chemical synthesis. Found in all forms of life, ATP is often referred to as the "molecular unit of [[Finance:Currency|currency]]" of intracellular energy transfer.<ref>{{cite journal |last=Knowles |first=J.&nbsp;R. |title=Enzyme-catalyzed phosphoryl transfer reactions |journal=Annu. Rev. Biochem. |volume=49 |pages=877–919 |year=1980 |pmid=6250450 | doi=10.1146/annurev.bi.49.070180.004305}}</ref>}}
{{term|term= '''[[Chemistry:Adhesion|Adhesion]]'''}}{{defn|defn=The tendency of dissimilar particles or surfaces to cling to one another (cohesion refers to the tendency of similar or identical particles/surfaces to cling to one another). }} 
{{term|term= '''[[Physics:Adiabatic process|Adiabatic process]]'''}}{{defn|defn=A process where no heat energy is lost to outside space.}}  
{{term|term= '''[[Physics:Adiabatic wall|Adiabatic wall]]'''}}{{defn|defn= A barrier through which heat energy cannot pass.}} 
{{term|term= '''[[Engineering:Aerobic digestion|Aerobic digestion]]'''}}{{defn|defn=A process in [[Earth:Sewage treatment|sewage treatment]]  designed to reduce the volume of sewage sludge and make it suitable<ref name="WEF">{{cite web|url=http://www.wefnet.org/mopnew/Operation_of_Municipal_Wastewater_Treatment_Plants/Chapter%2020.173-20.188%20Revised_6th%20Edition.pdf|title=Aerobic Diestion|publisher=Water Environment Federation|access-date=19 March 2016|archive-url=https://web.archive.org/web/20160327011438/http://www.wefnet.org/mopnew/Operation_of_Municipal_Wastewater_Treatment_Plants/Chapter%2020.173-20.188%20Revised_6th%20Edition.pdf|archive-date=27 March 2016|url-status=dead|df=dmy-all}}</ref> for subsequent use.<ref name="Handbook">{{cite web|url=http://www.wastewaterhandbook.com/webpg/th_sludge_82aerobic_digestion.htm|title=Handbook Biological Wastewater Treatment - Design of Activated Sludge Systems|access-date=19 March 2016}}</ref>}}
{{term|term= '''[[Physics:Aerodynamics|Aerodynamics]]'''}}{{defn|defn=The study of the motion of air, particularly its interaction with a solid object, such as an airplane wing. It is a sub-field of fluid dynamics and gas dynamics, and many aspects of aerodynamics theory are common to these fields.}}
{{term|term= '''[[Engineering:Aerospace engineering|Aerospace engineering]]'''}}{{defn|defn=Is the primary field of [[Engineering:Engineering|engineering]] concerned with the development of [[Engineering:Aircraft|aircraft]] and [[Engineering:Spacecraft|spacecraft]].<ref>''Encyclopedia of Aerospace Engineering''. {{wipe|John Wiley & Sons}}, 2010. {{ISBN|978-0-470-75440-5}}.</ref> It has two major and overlapping branches: Aeronautical engineering and Astronautical Engineering. [[Engineering:Avionics|Avionics]] engineering is similar, but deals with the [[Electronic engineering|electronics]] side of aerospace engineering.

 }}
{{term|term= '''[[Physics:Afocal system|Afocal system]]'''}}{{defn|defn=An optical system that produces no net convergence or divergence of the beam, i.e. has an infinite effective focal length.<ref>[https://books.google.com/books?id=4nxMduNT8-gC&pg=PA379&dq=afocal&lr=&cd=14#v=onepage&q=afocal&f=false Daniel Malacara, Zacarias Malacara, Handbook of optical design. Page 379]</ref>}}
{{term|term= '''[[Earth:Agricultural engineering|Agricultural engineering]]'''}}{{defn|defn=The profession of designing machinery, processes, and systems for use in agriculture.}}
{{term|term= '''[[Earth:Albedo|Albedo]]'''}}{{defn|defn=A measure of the fraction of light reflected from an astronomical body or other object.}}
{{term|term= '''[[Chemistry:Alkane|Alkane]]'''}}{{defn|defn=An alkane, or ''paraffin'' (a historical name that also has other meanings), is an [[Physics:Open-chain compound|acyclic]] [[Chemistry:Saturated and unsaturated compounds|saturated]] [[Chemistry:Hydrocarbon|hydrocarbon]]. In other words, an alkane consists of [[Chemistry:Hydrogen|hydrogen]] and [[Chemistry:Carbon|carbon]] atoms arranged in a [[Tree (graph theory)|tree]] structure in which all the [[Chemistry:Carbon–carbon bond|carbon–carbon bond]]s are [[Chemistry:Single bond|single]].<ref name="goldbook-alkanes">{{cite book |chapter-url=http://goldbook.iupac.org/A00222.html |title=IUPAC Gold Book - alkanes |publisher=IUPAC |date=March 27, 2017 |access-date=2018-08-23|doi=10.1351/goldbook.A00222 |chapter=Alkanes |isbn=978-0-9678550-9-7 }}</ref> }}
{{term|term= '''[[Chemistry:Alkene|Alkene]]'''}}{{defn|defn=An [[Chemistry:Unsaturated hydrocarbon|unsaturated hydrocarbon]] that contains at least one [[Chemistry:Carbon|carbon]]–carbon [[Chemistry:Double bond|double bond]].<ref name="Wade">{{cite book|last=Wade|first=L.G.|title=Organic Chemistry|url=https://archive.org/details/organicchemistry00wade_388|url-access=limited|publisher=Pearson Prentice Hall|date=2006|edition=6th|page=[https://archive.org/details/organicchemistry00wade_388/page/n321 279]|isbn=978-1-4058-5345-3}}</ref> The words alkene and olefin are often used interchangeably. }}
{{term|term= '''[[Chemistry:Alkyne|Alkyne]]'''}}{{defn|defn=Is an [[Chemistry:Saturated and unsaturated compounds|unsaturated]] [[Chemistry:Hydrocarbon|hydrocarbon]] containing at least one carbon—carbon [[Chemistry:Triple bond|triple bond]].<ref>[http://www.britannica.com/EBchecked/topic/15818/alkyne Alkyne]. Encyclopædia Britannica</ref> The simplest acyclic alkynes with only one triple bond and no other [[Chemistry:Functional group|functional group]]s form a [[Chemistry:Homologous series|homologous series]] with the general chemical formula {{Carbon}}<sub>''n''</sub>{{Hydrogen}}<sub>2''n''−2</sub>.}}
{{term|term= '''[[Chemistry:Alloy|Alloy]]'''}}{{defn|defn=is a combination of [[Chemistry:Metal|metal]]s or of a metal and another [[Chemistry:Chemical element|element]]. Alloys are defined by a [[Chemistry:Metallic bonding|metallic bonding]] character.<ref>Callister, W. D. "Materials Science and Engineering: An Introduction" 2007, 7th edition, John Wiley and Sons, Inc. New York, Section 4.3 and Chapter 9.</ref>}}
{{term|term= '''[[Physics:Alpha particle|Alpha particle]]'''}}{{defn|defn=Alpha particles consist of two [[Physics:Proton|proton]]s and two [[Physics:Neutron|neutron]]s bound together into a particle identical to a [[Physics:Helium-4|helium-4]] [[Physics:Atomic nucleus|nucleus]]. They are generally produced in the process of [[Physics:Alpha decay|alpha decay]], but may also be produced in other ways. Alpha particles are named after the first letter in the Greek alphabet, α.}} 
{{term|term= '''[[Physics:Alternating current|Alternating current]]'''}}{{defn|defn=Electrical current that regularly reverses direction.}} 
{{term|term= '''[[Alternative hypothesis]]'''}}{{defn|defn=In [[Statistical hypothesis testing|statistical hypothesis testing]],
the alternative hypothesis (or ''maintained hypothesis'' or ''research hypothesis'') and the [[Null hypothesis|null hypothesis]] are the two rival hypotheses which are compared by a [[Statistical hypothesis testing|statistical hypothesis test]]. In the domain of science two rival hypotheses can be compared by [[Explanatory power|explanatory power]] and [[Philosophy:Predictive power|predictive power]].}}
{{term|term= '''[[Engineering:Ammeter|Ammeter]]'''}}{{defn|defn=An instrument that measures current.}}
{{term|term= '''Amino acids'''}}{{defn|defn=Are [[Chemistry:Organic compound|organic compound]]s containing [[Chemistry:Amine|amine]] (-NH<sub>2</sub>) and [[Chemistry:Carboxylic acid|carboxyl]] (-COOH) [[Chemistry:Functional group|functional group]]s, along with a [[Chemistry:Substituent|side chain]] (R group) specific to each amino acid.<ref>{{Cite encyclopedia|title = Amino|date = 2015|encyclopedia = Dictionary.com|url = http://dictionary.reference.com/browse/amino|access-date = 3 July 2015}}</ref><ref>{{Cite encyclopedia|title = amino acid|date = 2015|encyclopedia = Cambridge Dictionaries Online|publisher = Cambridge University Press|url = https://dictionary.cambridge.org/us/dictionary/british/amino-acid|access-date = 3 July 2015}}</ref><ref>{{Cite encyclopedia|title = amino|date = 2015|publisher = Farlex|url = http://www.thefreedictionary.com/amino|access-date = 3 July 2015|encyclopedia = FreeDictionary.com}}</ref> The key [[Chemistry:Chemical element|elements]] of an amino acid are [[Chemistry:Carbon|carbon]] (C), [[Chemistry:Hydrogen|hydrogen]] (H), [[Chemistry:Oxygen|oxygen]] (O), and [[Chemistry:Nitrogen|nitrogen]] (N), although other elements are found in the side chains of certain amino acids. About 500 naturally occurring amino acids are known (though only 20 appear in the [[Biology:Genetic code|genetic code]]) and can be classified in many ways.<ref>{{cite journal |title = New Naturally Occurring Amino Acids|vauthors = Wagner I, Musso H|doi = 10.1002/anie.198308161|journal = Angewandte Chemie International Edition in English|volume = 22|issue = 11|pages = 816–28|date = November 1983}}{{Closed access}}</ref>}} 
{{term|term= '''[[Physics:Amorphous solid|Amorphous solid]]'''}}{{defn|defn= An amorphous (from the Greek a, without, morphé, shape, form) or non-crystalline solid is a solid that lacks the long-range order that is characteristic of a crystal.}}
{{term|term= '''[[Ampere]]'''}}{{defn|defn=The SI unit of current flow, one coulomb per second.}} 
{{term|term= '''[[Chemistry:Amphoterism|Amphoterism]]'''}}{{defn|defn=In chemistry, an '''amphoteric''' compound is a molecule or ion that can react both as an [[Chemistry:Acid|acid]] as well as a [[Chemistry:Base|base]].<ref>{{GoldBookRef | title = amphoteric | file = A00306}}</ref> Many metals (such as [[Chemistry:Copper|copper]], [[Chemistry:Zinc|zinc]], [[Chemistry:Tin|tin]], [[Chemistry:Lead|lead]], [[Chemistry:Aluminium|aluminium]], and [[Chemistry:Beryllium|beryllium]]) form amphoteric oxides or hydroxides. Amphoterism depends on the oxidation states of the oxide. Al<sub>2</sub>O<sub>3</sub> is an example of an amphoteric oxide.}}
{{term|term= '''[[Engineering:Amplifier|Amplifier]]'''}}{{defn|defn=A device that replicates a signal with increased power.}}
{{term|term= '''[[Physics:Amplitude|Amplitude]]'''}}{{defn|defn=The amplitude of a [[Periodic function|period]]ic [[Variable (mathematics)|variable]] is a measure of its change over a single period (such as time or [[Wavelength|spatial period]]). There are various definitions of amplitude, which are all [[Function (mathematics)|function]]s of the magnitude of the difference between the variable's [[Maxima and minima|extreme values]]. In older texts the [[Physics:Phase (waves)|phase]] is sometimes called the amplitude.<ref>{{Cite book | author1=Knopp, Konrad| author2= Bagemihl, Frederick |  title=Theory of Functions Parts I and II | year=1996 | publisher=Dover Publications | isbn=978-0-486-69219-7 | page=3}}</ref>}}
{{term|term= '''[[Physics:Anaerobic digestion|Anaerobic digestion]]'''}}{{defn|defn= Is a collection of processes by which microorganisms break down biodegradable material in the absence of [[Chemistry:Oxygen|oxygen]].<ref name="nnfcc">National Non-Food Crops Centre. [http://www.nnfcc.co.uk/publications/nnfcc-renewable-fuels-and-energy-factsheet-anaerobic-digestion "NNFCC Renewable Fuels and Energy Factsheet: Anaerobic Digestion"], Retrieved on 2011-11-22</ref> The process is used for industrial or domestic purposes to [[Social:Waste management|manage waste]] or to produce fuels. Much of the fermentation used industrially to produce food and drink products, as well as home fermentation, uses anaerobic digestion.}}
{{term|term= '''[[Physics:Angular acceleration|Angular acceleration]]'''}}{{defn|defn=Is the  rate of change of [[Physics:Angular velocity|angular velocity]]. In three dimensions, it is a [[Pseudovector|pseudovector]]. In SI units, it is measured in radians per [[Second|second]] squared (rad/s{{sup|2}}), and is usually denoted by the Greek letter alpha (α).<ref>{{cite web |url=http://theory.uwinnipeg.ca/physics/circ/node3.html |title=Angular Velocity and Acceleration |publisher=Theory.uwinnipeg.ca |access-date=2015-04-13 |archive-url=https://web.archive.org/web/20120222015414/http://theory.uwinnipeg.ca/physics/circ/node3.html |archive-date=2012-02-22 |url-status=dead }}</ref>}}
{{term|term= '''[[Physics:Angular momentum|Angular momentum]]'''}}{{defn|defn=In [[Physics:Physics|physics]], angular momentum (rarely, ''moment of momentum'' or ''rotational momentum'') is the rotational equivalent of linear momentum. It is an important quantity in physics because it is a [[Conservation law|conserved quantity]]—the total angular momentum of a system remains constant unless acted on by an external [[Physics:Torque|torque]].}}
{{term|term= '''[[Physics:Angular velocity|Angular velocity]]'''}}{{defn|defn=In [[Physics:Physics|physics]], the angular velocity of a particle is the rate at which it rotates around a chosen center point: that is, the time rate of change of its [[Physics:Angular displacement|angular displacement]] relative to the origin (i.e. in layman's terms: how quickly an object goes around something over a period of time - e.g. how fast the earth orbits the sun). It is measured in angle per unit time, radians per second in SI units, and is usually represented by the symbol omega ('''ω''', sometimes '''Ω'''). By convention, positive angular velocity indicates counter-clockwise rotation, while negative is clockwise.}}
{{term|term= '''Anion'''}}{{defn|defn=Is an ion with more electrons than protons, giving it a net negative charge (since electrons are negatively charged and protons are positively charged).<ref>{{cite web | url=http://ruby.colorado.edu/~smyth/G101-2.html | title =Atoms and Elements, Isotopes and Ions | author =University of Colorado Boulder | publisher =colorado.edu | date =November 21, 2013| }}</ref>}}
{{term|term= '''[[Engineering:Annealing (metallurgy)|Annealing (metallurgy)]]'''}}{{defn|defn=A heat treatment process that relieves internal stresses.}}
{{term|term= '''[[Physics:Annihilation|Annihilation]]'''}}{{defn|defn=In [[Physics:Particle physics|particle physics]], annihilation is the process that occurs when a [[Physics:Subatomic particle|subatomic particle]] collides with its respective [[Physics:Antiparticle|antiparticle]] to produce other particles, such as an [[Physics:Electron|electron]] colliding with a [[Physics:Positron|positron]] to produce two [[Physics:Photon|photon]]s.<ref>
{{cite web
 |title=Antimatter
 |url=http://www.lbl.gov/abc/Antimatter.html
 |publisher=[[Organization:Lawrence Berkeley National Laboratory|Lawrence Berkeley National Laboratory]]
 |access-date=3 September 2008
 |archive-url=https://web.archive.org/web/20080823180515/http://www.lbl.gov/abc/Antimatter.html
 |archive-date=23 August 2008 
 |url-status=live
}}</ref> The total [[Physics:Energy|energy]] and [[Physics:Momentum|momentum]] of the initial pair are conserved in the process and distributed among a set of other particles in the final state. Antiparticles have exactly opposite additive [[Physics:Quantum number|quantum number]]s from particles, so the sums of all quantum numbers of such an original pair are zero. Hence, any set of particles may be produced whose total quantum numbers are also zero as long as [[Physics:Conservation of energy|conservation of energy]] and [[Physics:Conservation of momentum|conservation of momentum]] are obeyed.<ref name=Particleadventure.org>
{{cite web
 |title=The Standard Model – Particle decays and annihilations
 |url=http://particleadventure.org/eedd.html
 |work=The Particle Adventure: The Fundamentals of Matter and Force
 |publisher=[[Organization:Lawrence Berkeley National Laboratory|Lawrence Berkeley National Laboratory]]
 |access-date=17 October 2011
}}</ref>}}
{{term|term= '''[[Physics:Anode|Anode]]'''}}{{defn|defn=The electrode at which current enters a device such as an electrochemical cell or vacuum tube.}}
{{term|term= '''ANSI'''}}{{defn|defn=The '''American National Standards Institute'''  is a private non-profit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States.<ref>{{IETF RFC|4949}}</ref> The organization also coordinates U.S. standards with international standards so that American products can be used worldwide.}}
{{term|term= '''[[Physics:Anti-gravity|Anti-gravity]]'''}}{{defn|defn=Anti-gravity (also known as ''non-gravitational field'') is a theory of creating a place or object that is free from the force of [[Physics:Gravity|gravity]]. It does not refer to the lack of weight under gravity experienced in [[Physics:Free fall|free fall]] or [[Physics:Orbit|orbit]], or to balancing the force of gravity with some other force, such as electromagnetism or aerodynamic lift.}}
{{term|term= '''Applied engineering'''}}{{defn|defn=Is the field concerned with the application of management, design, and technical skills for the design and integration of systems, the execution of new product designs, the improvement of manufacturing processes, and the management and direction of physical and/or technical functions of a firm or organization. Applied-engineering degreed programs typically include instruction in basic engineering principles, [[Project management|project management]], industrial processes, production and operations management, systems integration and control, quality control, and statistics.<ref>{{Cite web |url=https://atmae.site-ym.com/?page=AboutATMAE |title=ATMAE Venn Diagram |access-date=2018-11-15 |archive-date=2017-06-30 |archive-url=https://web.archive.org/web/20170630094708/https://atmae.site-ym.com/?page=AboutATMAE |url-status=dead }}</ref>}}
{{term|term= '''[[Applied mathematics]]'''}}{{defn|defn=Mathematics used for solutions of practical problems, as opposed to pure mathematics.}}
{{term|term= '''[[Arc length]]'''}}{{defn|defn=Determining the '''length of an irregular arc segment''' is also called rectification of a [[Curve|curve]]. Historically, many methods were used for specific curves. The advent of infinitesimal calculus led to a general formula that provides [[Closed-form expression|closed-form solutions]] in some cases.}}
{{term|term= '''[[Physics:Archimedes' principle|Archimedes' principle]]'''}}{{defn|defn=States that the upward [[Physics:Buoyancy|buoyant force]] that is exerted on a body immersed in a [[Physics:Fluid|fluid]], whether fully or partially submerged, is equal to the [[Physics:Weight|weight]] of the fluid that the body [[Physics:Displacement (fluid)|displaces]] and acts in the upward direction at the center of mass of the displaced fluid.<ref>{{Cite web | url=https://www.khanacademy.org/science/physics/fluids/buoyant-force-and-archimedes-principle/a/buoyant-force-and-archimedes-principle-article | title=What is buoyant force?}}</ref> Archimedes' principle is a law of physics fundamental to fluid mechanics. It was formulated by [[Biography:Archimedes|Archimedes of Syracuse]].<ref name="acottLaw"/>}}
{{term|term= '''Area moment of inertia'''}}{{defn|defn=The '''2nd moment of area''', also known as '''moment of inertia of plane area''', '''area moment of inertia''', or '''second area moment''', is a geometrical property of an area which reflects how its points are distributed with regard to an arbitrary axis. The second moment of area is typically denoted with either an <math>I</math> for an axis that lies in the plane or with a <math>J</math> for an axis perpendicular to the plane. In both cases, it is calculated with a [[Multiple integral|multiple integral]] over the object in question. Its dimension is L (length) to the fourth power. Its unit of dimension when working with the [[International System of Units]] is meters to the fourth power, [[Metre|m]]<sup>4</sup>. }}
{{term|term= '''[[Arithmetic mean]]'''}}{{defn|defn=In [[Mathematics|mathematics]] and [[Statistics|statistics]], the '''arithmetic mean'''  or simply the [[Mean|mean]] or '''average''' when the context is clear, is the sum of a collection of numbers divided by the number of numbers in the collection.<ref>{{cite book | last = Jacobs | first = Harold R. | title = Mathematics: A Human Endeavor | edition = Third | year = 1994 | publisher = W. H. Freeman | page = 547 | isbn = 978-0-7167-2426-1}}</ref>}}
{{term|term= '''[[Arithmetic progression]]'''}}{{defn|defn=In [[Mathematics|mathematics]], an '''arithmetic progression ''' (AP) or '''arithmetic sequence''' is a [[Sequence|sequence]] of [[Number|number]]s such that the difference between the consecutive terms is constant. Difference here means the second minus the first. For instance, the sequence  5, 7, 9, 11, 13, 15, . . . is an arithmetic progression with ''common difference'' of 2.}}
{{term|term= '''[[Chemistry:Aromatic hydrocarbon|Aromatic hydrocarbon]]'''}}{{defn|defn=An '''aromatic hydrocarbon''' or '''arene'''<ref>{{GoldBookRef |title=arenes |file=A00435}}</ref> (or sometimes '''aryl hydrocarbon''')<ref>[http://diss.kib.ki.se/2003/91-7349-549-2/thesis.pdf Mechanisms of Activation of the Aryl Hydrocarbon Receptor] by Maria Backlund, Institute of Environmental Medicine, Karolinska Institutet.</ref> is a [[Chemistry:Hydrocarbon|hydrocarbon]] with [[Chemistry:Sigma bond|sigma bond]]s and delocalized pi electrons between carbon atoms forming a circle. In contrast, [[Chemistry:Aliphatic compound|aliphatic]] hydrocarbons lack this delocalization. The term "aromatic" was assigned before the physical mechanism determining [[Chemistry:Aromaticity|aromaticity]] was discovered; the term was coined as such simply because many of the compounds have a sweet or pleasant odour. The configuration of six carbon atoms in aromatic compounds is known as a benzene ring, after the simplest possible such hydrocarbon, [[Chemistry:Benzene|benzene]]. Aromatic hydrocarbons can be ''monocyclic'' (MAH) or ''polycyclic'' (PAH).}}
{{term|term= '''[[Arrhenius equation]]'''}}{{defn|defn=The Arrhenius equation is a formula for the temperature dependence of [[Physics:Reaction rate|reaction rate]]s. The equation was proposed by [[Biography:Svante Arrhenius|Svante Arrhenius]] in 1889, based on the work of Dutch chemist [[Biography:Jacobus Henricus van 't Hoff|Jacobus Henricus van 't Hoff]] who had noted in 1884 that [[Van 't Hoff equation|Van 't Hoff's equation]] for the temperature dependence of [[Chemistry:Equilibrium constant|equilibrium constant]]s suggests such a formula for the rates of both forward and reverse reactions. This equation has a vast and important application in determining rate of chemical reactions and for calculation  of energy of activation. Arrhenius provided a physical justification and interpretation for the formula.<ref name="Arrhenius96">{{cite journal|first = S.A.|last = Arrhenius|title = Über die Dissociationswärme und den Einfluß der Temperatur auf den Dissociationsgrad der Elektrolyte|journal = Z. Phys. Chem.|volume = 4|pages = 96–116|year = 1889|doi=10.1515/zpch-1889-0408|s2cid = 202553486|url = https://zenodo.org/record/1448930}}</ref><ref name="Arrhenius226">{{cite journal|first = S.A.|last = Arrhenius|title = Über die Reaktionsgeschwindigkeit bei der Inversion von Rohrzucker durch Säuren|journal = ibid.|volume = 4|pages = 226–248|year = 1889}}</ref><ref name="Laidler42">Laidler, K. J. (1987) ''Chemical Kinetics'', Third Edition, Harper & Row, p.42</ref> Currently, it is best seen as an empirical relationship.<ref name="Connors">Kenneth Connors, Chemical Kinetics, 1990, VCH Publishers {{Google books|nHux3YED1HsC|Chemical Kinetics: The Study of Reaction Rates in Solution}}</ref>{{rp|188}} It can be used to model the temperature variation of diffusion coefficients, population of crystal vacancies, creep rates, and many other thermally-induced processes/reactions. The [[Eyring equation]], developed in 1935, also expresses the relationship between rate and energy.}}
{{term|term= '''[[Artificial intelligence]]'''}}{{defn|defn=(AI), is [[Philosophy:Intelligence|intelligence]] demonstrated by machines, unlike the natural intelligence<!--boldface per WP:R#PLA--> [[Philosophy:Human intelligence|displayed by humans]] and [[Biology:Animal cognition|animals]]. Leading AI textbooks define the field as the study of "[[Intelligent agent|intelligent agent]]s": any device that perceives its environment and takes actions that maximize its chance of successfully achieving its goals.{{refn|name="Definition of AI"|Definition of AI as the study of intelligent agents:
* {{Harvtxt|Poole|Mackworth|Goebel|1998}}, which provides the version that is used in this article. These authors use the term "computational intelligence" as a synonym for artificial intelligence.{{sfn|Poole|Mackworth|Goebel|1998|loc=[http://people.cs.ubc.ca/~poole/ci/ch1.pdf p. 1]}}
* {{Harvtxt|Russell|Norvig|2003}} (who prefer the term "rational agent") and write "The whole-agent view is now widely accepted in the field".{{sfn|Russell|Norvig|2003|p=55}}
* {{Harvnb|Nilsson|1998}} <!--These textbooks are the most widely used in academic AI.-->
* {{Harvnb|Legg|Hutter|2007}}}} Colloquially, the term "artificial intelligence" is often used to describe machines (or computers) that mimic "cognitive" functions that humans associate with the human mind, such as "learning" and "problem solving".{{sfn|Russell|Norvig|2009|p=2}}}} 
{{term|term= '''[[Assembly language]]'''}}{{defn|defn=A computer programming language where most statements correspond to one or a few machine op-codes.}} 
{{term|term= '''[[Physics:Atomic orbital|Atomic orbital]]'''}}{{defn|defn=In [[Physics:Atomic theory|atomic theory]] and [[Physics:Quantum mechanics|quantum mechanics]], an atomic orbital is a [[Function (mathematics)|mathematical function]] that describes the wave-like behavior of either one [[Physics:Electron|electron]] or a pair of electrons in an [[Physics:Atom|atom]].<ref>{{cite book|first1= Milton|last1= Orchin|first2=Roger S.|last2=Macomber|first3=Allan|last3=Pinhas|first4=R. Marshall|last4= Wilson|year=2005|url=http://media.wiley.com/product_data/excerpt/81/04716802/0471680281.pdf|title= Atomic Orbital Theory}}</ref> This function can be used to calculate the [[Probability|probability]] of finding any electron of an atom in any specific region around the [[Physics:Atomic nucleus|atom's nucleus]]. The term ''atomic orbital'' may also refer to the physical region or space where the electron can be calculated to be present, as defined by the particular mathematical form of the orbital.<ref>{{cite book|last=Daintith|first= J.|title=Oxford Dictionary of Chemistry|location=New York|publisher=Oxford University Press|year=2004|isbn=978-0-19-860918-6}}</ref>}}
{{term|term= '''[[Physics:Atomic packing factor|Atomic packing factor]]'''}}{{defn|defn=The percentage of the volume filled with atomic mass in a crystal formation.}}  
{{term|term= '''[[Physics:Audio frequency|Audio frequency]]'''}}{{defn|defn=An audio frequency (abbreviation: AF), or '''audible frequency''' is characterized as a [[Periodic function|periodic]] [[Vibration|vibration]] whose [[Physics:Frequency|frequency]] is audible to the average human. The [[International System of Units|SI unit]] of audio frequency is the [[Hertz|hertz]] (Hz). It is the property of [[Physics:Sound|sound]] that most determines [[Physics:Pitch (music)|pitch]].<ref>{{Cite book|last1= Pilhofer |first1=Michael |title=Music Theory for Dummies|url=https://books.google.com/books?id=CxcviUw4KX8C|year=2007|publisher=For Dummies|page=97|isbn=9780470167946 }}</ref>}} 
{{term|term= '''[[Chemistry:Austenite#Austenitization|Austenitization]]'''}}{{defn|defn='''Austenitization''' means to heat the iron, iron-based metal, or steel to a temperature at which it changes crystal structure from ferrite to austenite.<ref>{{cite web |author=Nichols R |title=Quenching and tempering of welded carbon steel tubulars |date=Jul 2001 |url=http://www.thefabricator.com/TubePipeFabrication/TubePipeFabrication_Article.cfm?ID=237 }}</ref> The more open structure of the austenite is then able to absorb carbon from the iron-carbides in carbon steel. An incomplete initial austenitization can leave undissolved [[Chemistry:Carbide|carbide]]s in the matrix.<ref name=Lambers>{{cite journal |vauthors=Lambers HG, Tschumak S, Maier HJ, Canadinc D |title=Role of Austenitization and Pre-Deformation on the Kinetics of the Isothermal Bainitic Transformation |journal=Metall. Mater. Trans. A |date=Apr 2009 |doi=10.1007/s11661-009-9827-z |bibcode=2009MMTA..tmp...74L |volume=40 |issue=6 |pages=1355–1366 |s2cid=136882327 }}</ref> For some irons, iron-based metals, and steels, the presence of carbides may occur during the austenitization step. The term commonly used for this is '''two-phase austenitization'''.<ref name=smnm>{{cite web|title=Austenitization|url=http://asmcommunity.asminternational.org/portal/site/www/AsmStore/ProductDetails/?vgnextoid=39c04ef322e18110VgnVCM100000701e010aRCRD }}</ref>}}
{{term|term= '''[[Engineering:Automation|Automation]]'''}}{{defn|defn=Is the technology  by which a process  or procedure is performed with minimum human assistance.<ref>{{cite book|title= Fundamentals of Modern Manufacturing: Materials, Processes, and Systems|last=Groover|first= Mikell|year=2014}}</ref> Automation<ref name="Rifkin 1995">{{cite book| author = Rifkin, Jeremy | title = The End of Work: The Decline of the Global Labor Force and the Dawn of the Post-Market Era | url = https://archive.org/details/endofwork00jere | url-access = registration | publisher = Putnam Publishing Group | year = 1995 | isbn = 978-0-87477-779-6|pages=[https://archive.org/details/endofwork00jere/page/66 66], 75}}</ref> or automatic control is the use of various [[Control system|control system]]s for operating equipment such as machinery, processes in factories, boilers and heat treating ovens, switching on telephone networks, steering and stabilization of ships, aircraft and other applications and vehicles with minimal or reduced human intervention. Some processes have been completely automated.}}
{{term|term= '''Autonomous vehicle'''}}{{defn|defn= A vehicle capable of driving from one point to another without input from a human operator.}} 
{{term|term= '''[[Physics:Azimuthal quantum number|Azimuthal quantum number]]'''}}{{defn|defn=The '''azimuthal quantum number''' is a [[Physics:Quantum number|quantum number]] for an [[Physics:Atomic orbital|atomic orbital]] that determines its [[Physics:Angular momentum operator|orbital angular momentum]] and describes the shape of the orbital. The azimuthal quantum number is the second of a set of quantum numbers which describe the unique [[Physics:Quantum state|quantum state]] of an electron (the others being the [[Physics:Principal quantum number|principal quantum number]], following [[Physics:Spectroscopic notation|spectroscopic notation]], the [[Physics:Magnetic quantum number|magnetic quantum number]], and the [[Physics:Spin quantum number|spin quantum number]]). It is also known as the '''orbital angular momentum''' quantum number, '''orbital quantum number''' or '''second quantum number''', and is symbolized as '''ℓ'''.}}
{{glossary end}}


==B==
{{glossary}}

{{term|term= '''[[Engineering:Barometer|Barometer]]'''}}{{defn|defn= A device for measuring pressure.}}
{{term|term= '''[[Physics:Battery (electricity)|Battery]]'''}}{{defn|defn=Electrochemical cells that transform chemical energy into electricity.}} 
{{term|term= '''[[Chemistry:Base|Base]]'''}}{{defn|defn=In [[Chemistry:Chemistry|chemistry]],  '''bases''' are substances that, in [[Chemistry:Aqueous solution|aqueous solution]], release [[Chemistry:Hydroxide|hydroxide]] (OH<sup>−</sup>) ions, are slippery to the touch, can taste [[Biology:Taste#bitter|bitter]] if an alkali,<ref>{{Cite book |title=Investigating chemistry: a forensic science perspective|last=Johll|first=Matthew E.|date=2009|publisher=W. H. Freeman and Co|isbn=978-1429209892|edition=2nd|location=New York |oclc=392223218}}</ref> change the color of indicators (e.g., turn red litmus paper blue), react with [[Chemistry:Acid|acid]]s to form salts, promote certain chemical reactions (base catalysis), accept [[Physics:Proton|proton]]s from any proton donor, and/or contain completely or partially displaceable OH<sup>−</sup> ions.}}
{{term|term= '''[[Baud]]'''}}{{defn|defn=Rate at which data is transferred in symbols/second; a symbol may represent one or more bits.}}
{{term|term= '''[[Physics:Beam (structure)|Beam]]'''}}{{defn|defn=A structural element whose length is significantly greater than its width or height.}}
{{term|term= '''[[Physics:Beer–Lambert law|Beer–Lambert law]]'''}}{{defn|defn=The '''Beer–Lambert law''', also known as '''Beer's law''', the '''Lambert–Beer law''', or the '''Beer–Lambert–Bouguer law''' relates the [[Physics:Absorption (electromagnetic radiation)|attenuation]] of [[Physics:Light|light]] to the properties of the material through which the light is travelling. The law is commonly applied to chemical analysis measurements and used in understanding attenuation in [[Physics:Physical optics|physical optics]], for [[Physics:Photons|photons]], neutrons or rarefied gases. In [[Physics:Mathematical physics|mathematical physics]], this law arises as a solution of the BGK equation.}}
{{term|term= '''[[Engineering:Belt (mechanical)|Belt]]'''}}{{defn|defn=A closed loop of flexible material used to transmit mechancial power from one pulley to another.}}
{{term|term= '''[[Physics:Belt friction|Belt friction]]'''}}{{defn|defn=Is a term describing the friction forces between a [[Engineering:Belt (mechanical)|belt]] and a surface, such as a belt wrapped around a [[Engineering:Bollard|bollard]]. When one end of the belt is being pulled only part of this force is transmitted to the other end wrapped about a surface. The friction force increases with the amount of wrap about a surface and makes it so the [[Physics:Tension|tension]] in the belt can be different at both ends of the belt. Belt friction can be modeled by the [[Physics:Capstan equation|Belt friction equation]].<ref name=Attaway>{{cite conference | last = Attaway | first = Stephen W. | title = The Mechanics of Friction in Rope Rescue | url = http://www.jrre.org/att_frict.pdf | access-date = February 1, 2010 | conference = International Technical Rescue Symposium | year = 1999}}</ref>}}
{{term|term= '''[[Physics:Bending|Bending]]'''}}{{defn|defn=In [[Physics:Applied mechanics|applied mechanics]], bending (also known as ''flexure'') characterizes the behavior of a slender structural element subjected to an external [[Structural load|load]] applied perpendicularly to a longitudinal axis of the element. The structural element is assumed to be such that at least one of its dimensions is a small fraction, typically 1/10 or less, of the other two.<ref name=Boresi>Boresi, A. P. and Schmidt, R. J. and Sidebottom, O. M., 1993, '''Advanced mechanics of materials''', John Wiley and Sons, New York.</ref>}}{{term|term= '''[[Physics:Bending moment|Bending moment]]'''}}{{defn|defn=In [[Physics:Solid mechanics|solid mechanics]], a bending moment is the [[Physics:Reaction|reaction]] induced in a [[Structural element|structural element]] when an external [[Physics:Force|force]] or moment is applied to the element, causing the element to [[Physics:Bending|bend]].<ref name=timo>{{Citation|last1=Gere|first1=J.M.|last2=Timoshenko|first2=S.P.|title=Mechanics of Materials:Forth edition|year=1996|publisher=Nelson Engineering|isbn=0534934293|url-access=registration|url=https://archive.org/details/mechanicsofmater00gere}}</ref>
<ref name=beer>{{Citation|last1=Beer|first1=F.|last2=Johnston|first2=E.R.|title=Vector mechanics for engineers: statics|publisher=McGraw Hill|year=1984|pages=62–76}}</ref> The most common or simplest structural element subjected to bending moments is the [[Physics:Beam (structure)|beam]].}} 
{{term|term= '''Benefit–cost analysis'''}}{{defn|defn='''Cost–benefit analysis''' ('''CBA'''), sometimes called '''benefit costs analysis''' ('''BCA'''), is a systematic approach to estimating the strengths and weaknesses of alternatives (for example in transactions, activities, functional business requirements); it is used to determine options that provide the best approach to achieve benefits while preserving savings.<ref>{{cite journal|last1=David|first1=Rodreck|last2=Ngulube|first2=Patrick|last3=Dube|first3=Adock|title=A cost-benefit analysis of document management strategies used at a financial institution in Zimbabwe: A case study|journal=SA Journal of Information Management|date=16 July 2013|volume=15|issue=2|doi=10.4102/sajim.v15i2.540|url=https://sajim.co.za/index.php/sajim/article/download/540/639|doi-access=free}}</ref> It may be used to compare potential (or completed) courses of actions; or estimate (or evaluate) the value against costs of a single decision, project, or policy.}}
{{term|term= '''[[Bernoulli differential equation]]'''}}{{defn|defn=In [[Mathematics|mathematics]], an [[Ordinary differential equation|ordinary differential equation]] of the form:

: <math>y'+ P(x)y = Q(x)y^n\,</math>

is called a '''Bernoulli differential equation''' where <math>n</math> is any real number and <math>n \ne 0</math> and <math>n \ne 1</math>.<ref>Weisstein, Eric W. "Bernoulli Differential Equation." From MathWorld--A Wolfram Web Resource. http://mathworld.wolfram.com/BernoulliDifferentialEquation.html</ref> It is named after [[Biography:Jacob Bernoulli|Jacob Bernoulli]] who discussed it in 1695. Bernoulli equations are special because they are nonlinear differential equations with known exact solutions. A famous special case of the Bernoulli equation is the logistic differential equation.}}
{{term|term= '''Bernoulli's equation'''}}{{defn|defn=An equation for relating several measurements within a fluid flow, such as velocity, pressure, and potential energy.}} 
{{term|term= '''[[Bernoulli's principle]]'''}}{{defn|defn=In [[Physics:Fluid dynamics|fluid dynamics]], '''Bernoulli's principle''' states that an increase in the speed of a fluid occurs simultaneously with a decrease in [[Physics:Pressure|pressure]] or a decrease in the [[Physics:Fluid|fluid]]'s [[Physics:Potential energy|potential energy]].<ref name="Clancy1975">{{cite book|last=Clancy|first=L. J. |title=Aerodynamics|url=https://books.google.com/books?id=zaNTAAAAMAAJ|year=1975|publisher=Wiley|isbn=978-0-470-15837-1}}</ref>{{rp|at=Ch.3}}<ref name="Batchelor2000">{{cite book|last=Batchelor|first=G. K. |author-link=George Batchelor|title=An Introduction to Fluid Dynamics|url=https://books.google.com/books?id=Rla7OihRvUgC&pg=PA156|year=2000|publisher=University Press|location=Cambridge |isbn=978-0-521-66396-0}}</ref>{{rp|at= § 3.5|pp=156–164}} The principle is named after [[Biography:Daniel Bernoulli|Daniel Bernoulli]] who published it in his book ''[[Physics:Hydrodynamica|Hydrodynamica]]'' in 1738.<ref>{{cite web | url =http://www.britannica.com/EBchecked/topic/658890/Hydrodynamica#tab=active~checked%2Citems~checked&title=Hydrodynamica%20–%20Britannica%20Online%20Encyclopedia | title=Hydrodynamica | access-date=2008-10-30 |publisher= Britannica Online Encyclopedia }}</ref> Although Bernoulli deduced that pressure decreases when the flow speed increases, it was [[Biography:Leonhard Euler|Leonhard Euler]] who derived '''Bernoulli's equation''' in its usual form in 1752.<ref name="Anderson2016">{{citation | title=Handbook of fluid dynamics | edition=2nd | editor-last=Johnson | editor-first=R.W. | chapter=Some reflections on the history of fluid dynamics | last=Anderson | first=J.D. | author-link=John D. Anderson | year=2016 | publisher=CRC Press | isbn=9781439849576|chapter-url={{google books|id=TQfYCwAAQBAJ|page=2-1|plainurl=yes|keywords=Anderson}} }}</ref><ref>{{citation | first1=O. | last1=Darrigol | first2=U. | last2=Frisch |title=From Newton's mechanics to Euler's equations | journal=Physica D: Nonlinear Phenomena | volume=237 | issue=14–17 | year=2008 | pages=1855–1869 | doi=10.1016/j.physd.2007.08.003 | bibcode=2008PhyD..237.1855D }}</ref> The principle is only applicable for isentropic flows: when the effects of [[Physics:Irreversible process|irreversible process]]es (like [[Physics:Turbulence|turbulence]]) and non-[[Physics:Adiabatic process|adiabatic process]]es (e.g. heat radiation) are small and can be neglected.}}
{{term|term= '''[[Physics:Beta particle|Beta particle]]'''}}{{defn|defn=also called '''beta ray''' or '''beta radiation''' (symbol '''β'''), is a high-energy, high-speed [[Physics:Electron|electron]] or [[Physics:Positron|positron]] emitted by the [[Physics:Radioactive decay|radioactive decay]] of an [[Physics:Atomic nucleus|atomic nucleus]] during the process of [[Physics:Beta decay|beta decay]]. There are two forms of beta decay, β<sup>−</sup> decay and β<sup>+</sup> decay, which produce electrons and positrons respectively.<ref>{{cite web
|title=Beta Decay
|url=http://www.lbl.gov/abc/wallchart/chapters/03/2.html
|work=Nuclear Wall Chart
|author=Lawrence Berkeley National Laboratory
|publisher=United States Department of Energy
|date=9 August 2000
|access-date=17 January 2016}}</ref>}}
{{term|term= '''[[Binomial distribution]]'''}}{{defn|defn=In [[Probability theory|probability theory]] and [[Statistics|statistics]], the '''binomial distribution''' with parameters ''n'' and ''p'' is the discrete probability distribution of the number of successes in a sequence of ''n'' independent [[Experiment (probability theory)|experiment]]s, each asking a yes–no question, and each with its own [[Boolean-valued function|boolean]]-valued [[Outcome (probability)|outcome]]: a [[Random variable|random variable]] containing a single [[Bit|bit]] of information: success/yes/[[Truth|true]]/one (with [[Probability|probability]] ''p'') or [[Engineering:Failure|failure]]/no/[[Philosophy:False (logic)|false]]/zero (with [[Probability|probability]] ''q'' = 1 − ''p''). 
A single success/failure experiment is also called a [[Bernoulli trial]] or Bernoulli experiment and a sequence of outcomes is called a [[Bernoulli process]]; for a single trial, i.e., ''n'' = 1, the binomial distribution is a [[Bernoulli distribution]]. The binomial distribution is the basis for the popular [[Binomial test|binomial test]] of [[Statistical significance|statistical significance]].}}
{{term|term= '''[[Medicine:Biomedical engineering|Biomedical engineering]]'''}}{{defn|defn='''Biomedical Engineering''' ('''BME''') or '''Medical Engineering''' is the application of engineering principles and design concepts to medicine and biology for healthcare purposes (e.g. diagnostic or therapeutic). This field seeks to close the gap between [[Engineering:Engineering|engineering]] and [[Medicine:Medicine|medicine]], combining the design and problem solving skills of engineering with medical biological sciences to advance health care treatment, including [[Medicine:Medical diagnosis|diagnosis]], monitoring, and [[Chemistry:Therapy|therapy]].<ref name="EnderleBronzino2012">{{cite book|author1=John Denis Enderle|author2=Joseph D. Bronzino|title=Introduction to Biomedical Engineering|url=https://books.google.com/books?id=twc-GLOtlOQC&pg=PP2|year=2012|publisher=Academic Press|isbn=978-0-12-374979-6|pages=16–}}</ref>}}
{{term|term= '''Biomimetic'''}}{{defn|defn='''Biomimetics''' or '''biomimicry''' is the imitation of the models, systems, and elements of nature for the purpose of solving complex [[Biology:Human|human]] problems.<ref>{{Cite journal|last1=Vincent|first1=Julian F. V.|title=Biomimetics: its practice and theory|journal=Journal of the Royal Society Interface|volume=3|issue=9|pages=471–482|doi=10.1098/rsif.2006.0127|pmid=16849244|pmc=1664643|date=22 August 2006|display-authors=0}}</ref>}}
{{term|term= '''[[Biology:Bionics|Bionics]]'''}}{{defn|defn= The application of biological methods to engineering systems.}}
{{term|term= '''[[Physics:Biophysics|Biophysics]]'''}}{{defn|defn= Is an interdisciplinary science that applies approaches and methods traditionally used in [[Physics:Physics|physics]] to study [[Biology:Biology|biological]] phenomena.<ref>{{Cite encyclopedia|url=https://www.britannica.com/science/biophysics|title=Biophysics {{!}} science|encyclopedia=Encyclopedia Britannica|access-date=2018-07-26}}</ref><ref>{{cite journal | vauthors = Zhou HX | title = Q&A: What is biophysics? | journal = BMC Biology | volume = 9 | page = 13 | date = March 2011 | pmid = 21371342 | pmc = 3055214 | doi = 10.1186/1741-7007-9-13 }}</ref><ref>{{Cite web|url=http://www.dictionary.com/browse/biophysics|title=the definition of biophysics|website=www.dictionary.com|language=en|access-date=2018-07-26}}</ref> Biophysics covers all scales of biological organization, from [[Physics:Molecule|molecular]] to organismic and populations. Biophysical research shares significant overlap with [[Biology:Biochemistry|biochemistry]], [[Biology:Molecular biology|molecular biology]], [[Chemistry:Physical chemistry|physical chemistry]], [[Biology:Physiology|physiology]], [[Engineering:Nanotechnology|nanotechnology]], bioengineering, [[Biology:Computational biology|computational biology]], [[Biology:Biomechanics|biomechanics]] and [[Biology:Systems biology|systems biology]].}}
{{term|term= '''[[Physics:Biot number|Biot number]]'''}}{{defn|defn=The '''Biot number''' ('''Bi''') is a [[Physics:Dimensionless quantity|dimensionless quantity]] used in heat transfer calculations. It is named after the eighteenth century French physicist [[Biography:Jean-Baptiste Biot|Jean-Baptiste Biot]] (1774–1862), and gives a simple index of the ratio of the heat transfer resistances ''inside of'' and ''at the surface of'' a body. This ratio determines whether or not the temperatures inside a body will vary significantly in space, while the body heats or cools over time, from a thermal gradient applied to its surface.}}
{{term|term= '''[[Physics:Block and tackle|Block and tackle]]'''}}{{defn|defn=A  system of pulleys and a rope threaded between them, used to lift or pull heavy loads.}}
{{term|term= '''[[Physics:Body force|Body force]]'''}}{{defn|defn=Is a force that acts throughout the volume of a body. Forces due to [[Physics:Gravity|gravity]], [[Physics:Electrostatics|electric fields]] and [[Physics:Magnetic fields|magnetic fields]] are examples of body forces. Body forces contrast with [[Physics:Contact force|contact force]]s or [[Physics:Surface force|surface force]]s which are exerted to the surface of an object.}}
{{term|term= '''[[Engineering:Boiler|Boiler]]'''}}{{defn|defn=Is a closed [[Physics:Pressure vessel|vessel]] in which [[Physics:Fluid|fluid]] (generally water) is heated. The fluid does not necessarily [[Physics:Boiling|boil]]. The heated or vaporized fluid exits the boiler for use in various processes or heating applications,<ref>{{cite book|author=Frederick M. Steingress|title=Low Pressure Boilers |edition=4th |publisher=American Technical Publishers|year=2001|isbn=0-8269-4417-5}}</ref><ref>{{cite book|author=Frederick M. Steingress, Harold J. Frost and Darryl R. Walker|title=High Pressure Boilers|edition=3rd |publisher=American Technical Publishers|year=2003|isbn=0-8269-4300-4}}</ref> including [[Engineering:Boiler (water heating)|water heating]], [[Engineering:Central heating|central heating]], [[Engineering:Boiler (power generation)|boiler-based power generation]], cooking, and [[Engineering:Sanitation|sanitation]]. }} 
{{term|term= '''[[Physics:Boiling point|Boiling point]]'''}}{{defn|defn=The boiling point of a substance is the temperature at which the [[Physics:Vapor pressure|vapor pressure]] of a [[Physics:Liquid|liquid]] equals the [[Physics:Pressure|pressure]] surrounding the liquid<ref>{{cite book|author=Goldberg, David E. |title=3,000 Solved Problems in Chemistry|edition=1st|publisher=McGraw-Hill|year=1988|isbn=0-07-023684-4 |at= section 17.43, p. 321 }}</ref><ref>{{cite book|editor1=Theodore, Louis |editor2=Dupont, R. Ryan |editor3=Ganesan, Kumar |title=Pollution Prevention: The Waste Management Approach to the 21st Century|publisher=CRC Press|year=1999|isbn=1-56670-495-2 |at= section 27, p. 15 }}</ref> and the liquid changes into a vapor.}} 
{{term|term= '''[[Chemistry:Boiling-point elevation|Boiling-point elevation]]'''}}{{defn|defn='''Boiling-point elevation''' describes the phenomenon that the [[Physics:Boiling point|boiling point]] of a [[Physics:Liquid|liquid]] (a [[Physics:Solvent|solvent]]) will be higher when another compound is added, meaning that a [[Chemistry:Solution|solution]] has a higher boiling point than a pure solvent. This happens whenever a non-volatile solute, such as a salt, is added to a pure solvent, such as water. The boiling point can be measured accurately using an [[Engineering:Ebullioscope|ebullioscope]].}}
{{term|term= '''[[Physics:Boltzmann constant|Boltzmann constant]]'''}}{{defn|defn=The '''Boltzmann constant''' ({{math|''k''<sub>B</sub>}} or {{mvar|k}}) is a [[Physics:Physical constant|physical constant]] relating the average [[Physics:Kinetic energy|kinetic energy]] of [[Physics:Particle|particle]]s in a [[Physics:Ideal gas|gas]] with the [[Physics:Temperature|temperature]] of the gas<ref name=Feynman1Ch39-10>{{cite book |author=Richard Feynman |title=The Feynman Lectures on Physics Vol I |publisher=Addison Wesley Longman |year=1970 |isbn=978-0-201-02115-8 |url=http://www.feynmanlectures.caltech.edu/I_39.html}}</ref> and occurs in [[Physics:Planck's law|Planck's law]] of [[Astronomy:Black-body radiation|black-body radiation]] and in [[Physics:Boltzmann's entropy formula|Boltzmann's entropy formula]]. It was introduced by [[Biography:Max Planck|Max Planck]], but named after [[Biography:Ludwig Boltzmann|Ludwig Boltzmann]].

It is the [[Physics:Gas constant|gas constant]] {{mvar|R}} divided by the [[Physics:Avogadro constant|Avogadro constant]] {{math|''N''<sub>A</sub>}}:

:<math> k = \frac{R}{N_\text{A}} .</math>.}}
{{term|term= '''[[Physics:Boson|Boson]]'''}}{{defn|defn=In [[Physics:Quantum mechanics|quantum mechanics]], a '''boson''' ({{IPAc-en|ˈ|b|oʊ|s|ɒ|n}},<ref>{{cite book |title=Longman pronunciation dictionary |first=John C. |last= Wells |publisher=Longman |location=Harlow, England |year=1990 |isbn=978-0582053830 }} entry "Boson"
</ref> {{IPAc-en|ˈ|b|oʊ|z|ɒ|n}}<ref>{{cite web
|title= boson|website=Collins Dictionary |url=http://www.collinsdictionary.com/dictionary/english/boson?showCookiePolicy=true}}</ref>) is a particle that follows [[Physics:Bose–Einstein statistics|Bose–Einstein statistics]]. Bosons make up one of the two classes of [[Physics:Elementary particle|particles]], the other being [[Physics:Fermion|fermion]]s.<ref name = DarkMatter>{{cite book |author=Carroll, Sean |year=2007 |series=Dark Matter, Dark Energy: The dark side of the universe |title=Guidebook |at=Part&nbsp;2, p.&nbsp;43 |publisher=The Teaching Company |isbn=978-1598033502 |quote=...&nbsp;boson: A force-carrying particle, as opposed to a matter particle (fermion). Bosons can be piled on top of each other without limit. Examples include photons, gluons, gravitons, weak bosons, and the Higgs boson. The spin of a boson is always an integer, such as 0, 1, 2, and so on&nbsp;...}}</ref> The name boson was coined by [[Biography:Paul Dirac|Paul Dirac]]<ref>{{cite book |title=Notes on Dirac's lecture ''Developments in Atomic Theory'' at Le Palais de la Découverte, 6&nbsp;December 1945 |publisher=UKNATARCHI Dirac Papers |id=BW83/2/257889}}</ref><ref>{{Cite book|url=https://books.google.com/books?id=qsodmIGD0fMC&q=farmelo+graham+the+strangest+man|title=The Strangest Man: The Hidden Life of Paul Dirac, Mystic of the Atom|last=Farmelo|first=Graham|date=2009-08-25|publisher=Basic Books|isbn=9780465019922|page=331}}</ref> to commemorate the contribution of Indian physicist and professor of physics at University of Calcutta and at University of Dhaka, [[Biography:Satyendra Nath Bose|Satyendra Nath Bose]]<ref name="AP-20120710">{{cite news |last=Daigle |first=Katy |title=India: Enough about Higgs, let's discuss the boson |url=http://apnews.excite.com/article/20120710/D9VU1DRG0.html |date=10 July 2012 |newspaper=AP News |access-date=10 July 2012}}</ref><ref name="NYT-20120919">{{cite news |last=Bal |first=Hartosh Singh |title=The Bose in the Boson |url= http://latitude.blogs.nytimes.com/2012/09/19/indians-clamor-for-credit-for-the-bose-in-boson/ |date=19 September 2012 |work={{wipe|The New York Times}} blog |access-date=21 September 2012}}</ref> in developing, with [[Biography:Albert Einstein|Albert Einstein]], Bose–Einstein statistics—which theorizes the characteristics of elementary particles.<ref>{{cite news |url= https://www.bbc.co.uk/news/magazine-18708741 |title=Higgs boson: The poetry of subatomic particles |date=4 July 2012|work=BBC News |access-date=6 July 2012}}</ref>}}
{{term|term= '''[[Boyle's law]]'''}}{{defn|defn='''Boyle's law''' (sometimes referred to as the '''Boyle–Mariotte law''', or '''Mariotte's law'''<ref>{{cite book|last=Draper|first=John William|title=A Textbook on chemistry|publisher=Harper & Bros.|year=1861|page=[https://archive.org/details/bub_gb_HKwS7QDh5eMC/page/n60 46]|url=https://archive.org/details/bub_gb_HKwS7QDh5eMC|quote=draper, john william.}}</ref>) is an experimental [[Physics:Gas laws|gas law]] that describes how the [[Physics:Pressure|pressure]] of a [[Physics:Gas|gas]] tends to increase as the [[Physics:Volume|volume]] of the container decreases. A modern statement of Boyle's law is: 
The absolute pressure exerted by a given mass of an [[Physics:Ideal gas|ideal gas]] is inversely proportional to the volume it occupies if the [[Physics:Temperature|temperature]] and [[Physics:Amount of substance|amount of gas]] remain unchanged within a [[Closed system|closed system]].<ref>Levine, Ira. N (1978). "Physical Chemistry" University of Brooklyn: McGraw-Hill</ref><ref name="levine_1">Levine, Ira. N. (1978), p. 12 gives the original definition.</ref>}}
{{term|term= '''[[Bravais lattice]]'''}}{{defn|defn=In [[Geometry|geometry]] and [[Physics:Crystallography|crystallography]], a '''Bravais lattice''', named after {{harvs|txt|first=Auguste |last=Bravais|year=1850|authorlink=Auguste Bravais}},<ref>{{cite journal|last1 = Aroyo|first1 = Mois I.|first2 = Ulrich|last2 = Müller|first3 = Hans|last3 = Wondratschek|title = Historical Introduction|journal = International Tables for Crystallography|volume = A1|issue = 1.1|pages = 2–5|year = 2006|url = http://it.iucr.org/A1a/ch1o1v0001/sec1o1o1/|doi = 10.1107/97809553602060000537|access-date = 2008-04-21|url-status = dead|archive-url = https://archive.today/20130704032928/http://it.iucr.org/A1a/ch1o1v0001/sec1o1o1/|archive-date = 2013-07-04|citeseerx = 10.1.1.471.4170}}</ref> is an infinite array (or a finite array, if we consider the edges, obviously) of discrete points generated by a set of [[Physics:Translation operator (quantum mechanics)#Discrete Translational Symmetry|discrete translation]] operations described in three dimensional space by:

:<math>\mathbf{R} = n_{1}\mathbf{a}_{1} + n_{2}\mathbf{a}_{2} + n_{3}\mathbf{a}_{3}</math>

where ''n<sub>i</sub>'' are any integers and '''a'''<sub>''i''</sub> are known as the primitive vectors which lie in different directions (not necessarily mutually perpendicular) and span the lattice. This discrete set of vectors must be closed under vector addition and subtraction. For any choice of position vector '''R''', the lattice looks exactly the same.}}
{{term|term= '''[[Physics:Brayton cycle|Brayton cycle]]'''}}{{defn|defn=A thermodynamic cycle model for an ideal heat engine, in which heat is added or removed at constant pressure; approximated by a gas turbine.}}
{{term|term= '''[[Finance:Break-even (economics)|Break-even]]'''}}{{defn|defn=The '''break-even point''' (BEP) in [[Finance:Economics|economics]], business—and specifically [[Social:Cost accounting|cost accounting]]—is the point at which total cost and total revenue are equal, i.e. "even". There is no net loss or gain, and one has "broken even", though [[Finance:Opportunity cost|opportunity cost]]s have been paid and capital has received the risk-adjusted, expected return. In short, all costs that must be paid are paid, and there is neither profit nor loss.<ref name='R000000'>{{cite book | last = Levine | first = David | author2= Michele Boldrin | title = Against Intellectual Monopoly | publisher = Cambridge University Press | date = 2008-09-07 | page = 312 | url = http://www.dklevine.com/general/intellectual/againstfinal.htm | isbn = 978-0-521-87928-6 }}</ref><ref>Tapang, Bienvenido, and Lorelei Mendoza. ''Introductory Economics.'' University of the Philippines, Baguio.</ref> }}
{{term|term= '''[[Brewster's angle]]'''}}{{defn|defn='''Brewster's angle''' (also known as the '''polarization angle''') is an [[Physics:Angle of incidence (optics)|angle of incidence]] at which [[Physics:Light|light]] with a particular [[Physics:Polarization (waves)|polarization]] is perfectly transmitted through a transparent [[Physics:Dielectric|dielectric]] surface, with ''no [[Physics:Reflection|reflection]]''. When ''unpolarized'' light is incident at this angle, the light that is reflected from the surface is therefore perfectly polarized. This special angle of incidence is named after the Scottish physicist [[Biography:David Brewster|Sir David Brewster]] (1781–1868).<ref>David Brewster (1815) [https://books.google.com/books?id=U-U_AAAAYAAJ&pg=PA125#v=onepage&q&f=false "On the laws which regulate the polarisation of light by reflection from transparent bodies,"] ''Philosophical Transactions of the Royal Society of London'', '''105''': 125-159.</ref><ref>{{cite journal |last=Lakhtakia |first=Akhlesh |date=June 1989 |title=Would Brewster recognize today's Brewster angle? |journal=Optics News |publisher=OSA |doi=10.1364/ON.15.6.000014 |volume=15 |issue=6 |pages=14–18 |url=http://www.esm.psu.edu/~axl4/lakhtakia/Documents/No087(ON).pdf }}</ref>}}
{{term|term= '''[[Physics:Brittleness|Brittleness]]'''}}{{defn|defn=A material is '''brittle''' if, when subjected to [[Physics:Stress|stress]], it breaks without significant plastic deformation. Brittle materials absorb relatively little [[Physics:Energy|energy]] prior to fracture, even those of high [[Physics:Strength of materials|strength]]. Breaking is often accompanied by a snapping sound. Brittle materials include most ceramics and [[Chemistry:Glass|glass]]es (which do not deform plastically) and some [[Chemistry:Polymer|polymer]]s, such as PMMA and [[Chemistry:Polystyrene|polystyrene]]. Many steels become brittle at low temperatures (see ductile-brittle transition temperature), depending on their composition and processing.}}
{{term|term= '''[[Chemistry:Bromide|Bromide]]'''}}{{defn|defn=Any chemical substance made up of Bromine, along with other elements.}}
{{term|term= '''[[Chemistry:Brønsted–Lowry acid–base theory|Brønsted–Lowry acid–base theory]]'''}}{{defn|defn=Is an [[Chemistry:Acid–base reaction|acid–base reaction]] theory which was proposed independently by Johannes Nicolaus Brønsted and Thomas Martin Lowry in 1923.<ref>{{cite journal|author=Brönsted, J. N. |year=1923|title=Einige Bemerkungen über den Begriff der Säuren und Basen|trans-title=Some observations about the concept of acids and bases|journal=Recueil des Travaux Chimiques des Pays-Bas|volume=42|issue=8|pages= 718–728|doi=10.1002/recl.19230420815}}</ref><ref>{{cite journal|author=Lowry, T. M. |year=1923|title=The uniqueness of hydrogen|doi=10.1002/jctb.5000420302|url=https://archive.org/stream/ost-chemistry-chemistryindustr01soci/chemistryindustr01soci#page/n65/mode/2up |journal=Journal of the Society of Chemical Industry|volume=42|issue=3|pages=43–47}}</ref> The fundamental concept of this theory is that when an acid and a base react with each other, the acid forms its [[Chemistry:Conjugate acid|conjugate base]], and the base forms its conjugate acid by exchange of a [[Physics:Proton|proton]] (the hydrogen cation, or H<sup>+</sup>). This theory is a generalization of the Arrhenius theory.}}
{{term|term= '''[[Brownian motion]]'''}}{{defn|defn='''Brownian motion''' or '''pedesis''' is the random motion of [[Physics:Particle|particle]]s suspended in a [[Physics:Fluid|fluid]] (a [[Physics:Liquid|liquid]] or a [[Physics:Gas|gas]]) resulting from their collision with the fast-moving [[Physics:Molecule|molecule]]s in the fluid.<ref name=Feynman-41>
{{cite book
 |last=Feynman |first=R.
 |year=1964
 |chapter=The Brownian Movement
 |chapter-url=http://www.feynmanlectures.caltech.edu/I_41.html
 |title=The Feynman Lectures of Physics, Volume I
 |pages=41{{hyphen}}1
}}</ref>}}
{{term|term= '''[[Buckingham π theorem]]'''}}{{defn|defn= A method for determining ∏ groups, or dimensionless descriptors of physical phenomena.}}
{{term|term= '''[[Chemistry:Buffer solution|Buffer solution]]'''}}{{defn|defn=A '''buffer solution''' (more precisely, [[Chemistry:PH|pH]] buffer or [[Physics:Hydrogen ion|hydrogen ion]] buffer) is an [[Chemistry:Aqueous solution|aqueous solution]] consisting of a [[Physics:Mixture|mixture]] of a [[Chemistry:Weak acid|weak acid]] and its conjugate base, or vice versa. Its pH changes very little when a small amount of strong acid or [[Chemistry:Base#Strong bases|base]] is added to it. Buffer solutions are used as a means of keeping pH at a nearly constant value in a wide variety of chemical applications. In nature, there are many systems that use buffering for pH regulation.}}
{{term|term= '''[[Physics:Bulk modulus|Bulk modulus]]'''}}{{defn|defn=The '''bulk modulus''' (<math>K</math> or <math>B</math>) of a substance is a measure of how resistant to compression that substance is. It is defined as the ratio of the [[Infinitesimal|infinitesimal]] [[Physics:Pressure|pressure]] increase to the resulting ''relative'' decrease of the [[Physics:Volume|volume]].<ref>{{cite web|url=http://hyperphysics.phy-astr.gsu.edu/hbase/permot3.html|title= Bulk Elastic Properties|work=hyperphysics|publisher=Georgia State University}}</ref> 
Other moduli describe the material's response ([[Physics:Strain (materials science)|strain]]) to other kinds of [[Physics:Stress|stress]]: the [[Physics:Shear modulus|shear modulus]] describes the response to shear, and [[Physics:Young's modulus|Young's modulus]] describes the response to linear stress. For a [[Physics:Fluid|fluid]], only the bulk modulus is meaningful. For a complex anisotropic solid such as [[Biology:Wood|wood]] or [[Chemistry:Paper|paper]], these three moduli do not contain enough information to describe its behaviour, and one must use the full generalized [[Physics:Hooke's law|Hooke's law]].}}
{{term|term= '''[[Physics:Buoyancy|Buoyancy]]'''}}{{defn|defn=A force caused by displacement in a fluid by an object of different density than the fluid.}} 
{{glossary end}}

==C==
{{glossary}}
{{term|term= '''[[Calculus]]'''}}{{defn|defn=The mathematics of change.}}
{{term|term= '''[[Physics:Capacitance|Capacitance]]'''}}{{defn|defn=The ability of a body to store electrical charge.}} 
{{term|term= '''Capacitive reactance'''}}{{defn|defn=The impedance of a capacitor in an alternating current circuit, the opposition to current flow.}}
{{term|term= '''[[Engineering:Capacitor|Capacitor]]'''}}{{defn|defn=An electrical component that stores energy in an electric field.}}
{{term|term= '''[[Physics:Capillary action|Capillary action]]'''}}{{defn|defn='''Capillary action''' (sometimes '''capillarity''', '''capillary motion''', '''capillary effect''', or '''wicking''') is the ability of a [[Physics:Liquid|liquid]] to flow in narrow spaces without the assistance of, or even in opposition to, external forces like gravity. The effect can be seen in the drawing up of liquids between the hairs of a paint-brush, in a thin tube, in porous materials such as paper and plaster, in some non-porous materials such as sand and liquefied carbon fiber, or in a cell. It occurs because of [[Physics:Intermolecular force|intermolecular force]]s between the liquid and surrounding solid surfaces. If the diameter of the tube is sufficiently small, then the combination of [[Physics:Surface tension|surface tension]] (which is caused by [[Chemistry:Cohesion|cohesion]] within the liquid) and [[Chemistry:Adhesion|adhesive forces]] between the liquid and container wall act to propel the liquid.<ref>{{cite web|url=http://science.jrank.org/pages/1182/Capillary-Action.html|title=Capillary Action – Liquid, Water, Force, and Surface – JRank Articles|publisher=Science.jrank.org|access-date=2013-06-18|url-status=live|archive-url=https://web.archive.org/web/20130527124752/http://science.jrank.org/pages/1182/Capillary-Action.html|archive-date=2013-05-27}}</ref>}}
{{term|term= '''[[Chemistry:Carbonate|Carbonate]]'''}}{{defn|defn=Any mineral with bound carbon dioxide.}}
{{term|term= '''[[Physics:Carnot cycle|Carnot cycle]]'''}}{{defn|defn=A hypothetical thermodynamic cycle for a heat engine; no thermodynamic cycle can be more efficient than a Carnot cycle operating between the same two temperature limits.}} 
{{term|term= '''Cartesian coordinates'''}}{{defn|defn=Coordinates within a rectangular Cartesian plane.}}
{{term|term= '''[[Castigliano's method]]'''}}{{defn|defn=Named for Carlo Alberto Castigliano, is a method for determining the displacements of a [[Physics:Linear elasticity|linear-elastic]] system based on the [[Partial derivative|partial derivative]]s  of the [[Physics:Energy|energy]]. He is known for his two theorems. The basic concept may be easy to understand by recalling that a change in energy is equal to the causing force times the resulting displacement. Therefore, the causing force is equal to the change in energy divided by the resulting displacement. Alternatively, the resulting displacement is equal to the change in energy divided by the causing force. Partial derivatives are needed to relate causing forces and resulting displacements to the change in energy.}}
{{term|term= '''Casting'''}}{{defn|defn=Forming of an object by pouring molten metal (or other substances) into a mold.}}
{{term|term= '''[[Physics:Cathode|Cathode]]'''}}{{defn|defn=The terminal of a device by which current exits.}}
{{term|term= '''[[Physics:Cathode ray|Cathode ray]]'''}}{{defn|defn=The stream of electrons emitted from a heated negative electrode and attracted to a positive electrode.}}
{{term|term= '''[[Biology:Cell membrane|Cell membrane]]'''}}{{defn|defn=The '''cell membrane''' (also known as the '''plasma membrane''' or '''cytoplasmic membrane,''' and historically referred to as the '''plasmalemma''') is a [[Biology:Biological membrane|biological membrane]] that separates the [[Biology:Cytoplasm|interior]] of all [[Biology:Cell|cells]] from the [[Biology:Extracellular space|outside environment]] (the extracellular space) which protects the cell from its environment<ref>[http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/CellMembranes.html Kimball's Biology pages] {{webarchive|url=https://web.archive.org/web/20090125224255/http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/CellMembranes.html |date=2009-01-25 }}, Cell Membranes</ref><ref>{{cite book |author1=Singleton P |title=Bacteria in Biology, Biotechnology and Medicine |edition=5th |isbn=978-0-471-98880-9 |year=1999 |publisher=Wiley |location=New York}}</ref> consisting of a [[Biology:Lipid bilayer|lipid bilayer]] with embedded [[Biology:Protein|protein]]s.}}
{{term|term= '''[[Biology:Cell nucleus|Cell nucleus]]'''}}{{defn|defn=In [[Biology:Cell biology|cell biology]], the  '''nucleus''' (pl. '''''nuclei'''''; from [[Social:Latin|Latin]] {{lang|la|nucleus}} or {{lang|la|nuculeus}}, meaning ''kernel'' or ''seed'') is a [[Biology:Biological membrane|membrane]]-enclosed [[Biology:Organelle|organelle]] found in [[Biology:Eukaryote|eukaryotic]] [[Biology:Cell|cells]]. Eukaryotes usually have a single nucleus, but a few cell types, such as mammalian red blood cells, have no nuclei, and a few others including [[Biology:Osteoclast|osteoclast]]s have [[Biology:Multinucleate|many]].}}
{{term|term= '''[[Biology:Cell theory|Cell theory]]'''}}{{defn|defn=In [[Biology:Biology|biology]], '''cell theory''' is the historic [[Scientific theory|scientific theory]], now universally accepted, that living organisms are made up of [[Biology:Cell|cell]]s, that they are the basic structural/organizational unit of all organisms, and that all cells come from pre-existing cells. Cells are the basic unit of structure in all organisms and also the basic unit of reproduction.}}
{{term|term= '''Center of gravity'''}}{{defn|defn=The center of mass of an object, its balance point. }} 
{{term|term= '''[[Physics:Center of mass|Center of mass]]'''}}{{defn|defn=The weighted center of an object; a force applied through the center of mass will not cause rotation of the object.}} 
{{term|term= '''[[Center of pressure (fluid mechanics)|Center of pressure]]'''}}{{defn|defn=Is the point where the total sum of a [[Physics:Pressure|pressure]] field acts on a body, causing a [[Physics:Force|force]] to act through that point. The total force vector acting at the center of pressure is the value of the integrated vectorial pressure field. The resultant force and center of pressure location produce equivalent force and moment on the body as the original pressure field.}} 
{{term|term= '''Central force motion'''}}{{defn|defn=.}}
{{term|term= '''[[Central limit theorem]]'''}}{{defn|defn=In [[Probability theory|probability theory]], the '''central limit theorem''' ('''CLT''') establishes that, in some situations, when independent random variables are added, their properly normalized sum tends toward a [[Normal distribution|normal distribution]] (informally a "''bell curve''") even if the original variables themselves are not normally distributed. The theorem is a key concept in probability theory because it implies that probabilistic and statistical methods that work for normal distributions can be applicable to many problems involving other types of distributions.}}
{{term|term= '''[[Central processing unit]]'''}}{{defn|defn=A '''central processing unit''' ('''CPU''') is the [[Physics:Electronic circuit|electronic circuit]]ry within a [[Computer|computer]] that carries out the instructions of a [[Computer program|computer program]] by performing the basic [[Arithmetic|arithmetic]], logic, controlling and [[Input output|input/output]] (I/O) operations specified by the instructions. The computer industry has used the term "central processing unit" at least since the early 1960s.<ref name="weik1961">{{cite web | author = Weik, Martin H. | title = A Third Survey of Domestic Electronic Digital Computing Systems | publisher = Ballistic Research Laboratory | url = http://ed-thelen.org/comp-hist/BRL61.html | year = 1961 }}</ref> Traditionally, the term "CPU" refers to a '''processor''', more specifically to its processing unit and [[Control unit|control unit]] (CU), distinguishing these core elements of a computer from external components such as main memory and I/O circuitry.<ref name="kuck">{{cite book|last1= Kuck|first1= David|title= Computers and Computations, Vol 1|date= 1978|publisher= John Wiley & Sons, Inc.|isbn= 978-0471027164|page= 12}}</ref>}}
{{term|term= '''[[Physics:Acceleration#Tangential and centripetal acceleration|Centripetal acceleration]]'''}}{{defn|defn=.}}
{{term|term= '''[[Physics:Centripetal force|Centripetal force]]'''}}{{defn|defn=A force acting against rotational acceleration.}} 
{{term|term= '''[[Centroid]]'''}}{{defn|defn=The average point of volume for an object.}} 
{{term|term= '''[[Biology:Centrosome|Centrosome]]'''}}{{defn|defn=In [[Biology:Cell biology|cell biology]], the '''centrosome''' is an [[Biology:Organelle|organelle]] that serves as the main [[Biology:Microtubule organizing center|microtubule organizing center]] (MTOC) of the animal [[Biology:Cell|cell]] as well as a regulator of cell-cycle progression. The centrosome is thought to have evolved only in the metazoan lineage of [[Biology:Eukaryote|eukaryotic cells]].<ref name="pmid17977464">{{Cite book |doi = 10.1007/978-0-387-74021-8_10
 |last2 = Azimzadeh
 |pmid = 17977464
 |isbn = 978-0-387-74020-1
 |year = 2008
 |pages = [https://archive.org/details/eukaryoticmembra00gasp/page/119 119–129]
 |series = Advances in Experimental Medicine and Biology
 |last1 = Bornens
 |first2 = J.
 |chapter = Origin and Evolution of the Centrosome
 |title = Eukaryotic Membranes and Cytoskeleton
 |volume = 607
 |first1 = M.
 |chapter-url = https://archive.org/details/eukaryoticmembra00gasp
 |url = https://archive.org/details/eukaryoticmembra00gasp/page/119
}}</ref> [[Biology:Fungus|Fungi]] and [[Biology:Plant|plant]]s lack centrosomes and therefore use structures other than MTOCs to organize their microtubules.<ref name="pmid12224551">{{Cite book 
| pages = 257–289 
| doi = 10.1016/S0074-7696(02)20008-X 
| series = International Review of Cytology 
| volume = 220 
| title = Acentrosomal microtubule nucleation in higher plants 
| year = 2002 
| author1 = Schmit 
| isbn = 9780123646248 
| pmid = 12224551
}}</ref><ref name="pmid15473833">{{Cite journal
| year = 2004
| pages = 1–28
| doi = 10.1146/annurev.cellbio.20.022003.114106
| last2 = Winey
| pmid = 15473833| issue = 1
| volume = 20| last1 = Jaspersen | first2 = M.
| title = THE BUDDING YEAST SPINDLE POLE BODY: Structure, Duplication, and Function
| journal = Annual Review of Cell and Developmental Biology| first1 = S. L.
}}</ref>}}
{{term|term= '''[[Philosophy:Chain reaction|Chain reaction]]'''}}{{defn|defn=Is a sequence of reactions where a reactive product or by-product causes additional reactions to take place. In a chain reaction, [[Positive feedback|positive feedback]] leads to a self-amplifying [[Philosophy:Chain of events|chain of events]].}}
{{term|term= '''Change of base rule'''}}{{defn|defn=.}}
{{term|term= '''[[Physics:Charles's law|Charles's law]]'''}}{{defn|defn='''Charles's law''' (also known as the '''law of volumes''') is an experimental [[Physics:Gas laws|gas law]] that describes how [[Physics:Gas|gas]]es [[Physics:Thermal expansion|tend to expand when heated]]. A modern statement of Charles's law is:
 When the [[Physics:Pressure|pressure]] on a sample of a dry gas is held constant, the Kelvin temperature and the volume will be in direct proportion.<ref>{{Citation| publisher = Heinemann|isbn = 0-435-57078-1| pages = 141–142| last = Fullick| first = P.| title = Physics| year = 1994}}</ref>}}
{{term|term= '''[[Chemistry:Chemical bond|Chemical bond]]'''}}{{defn|defn=Is a lasting attraction between [[Physics:Atom|atom]]s, ions or molecules that enables the formation of [[Chemistry:Chemical compound|chemical compound]]s. The bond may result from the [[Physics:Electrostatic force|electrostatic force]] of attraction between oppositely charged ions as in ionic bonds or through the sharing of electrons as in [[Chemistry:Covalent bond|covalent bond]]s. The strength of chemical bonds varies considerably; there are "strong bonds" or "primary bonds" such as covalent, ionic and [[Chemistry:Metallic bonding|metallic]] bonds, and "weak bonds" or "secondary bonds" such as dipole–dipole interactions, the [[Physics:London dispersion force|London dispersion force]] and [[Chemistry:Hydrogen bond|hydrogen bond]]ing.}} 
{{term|term= '''[[Chemistry:Chemical compound|Chemical compound]]'''}}{{defn|defn=Is a [[Chemistry:Chemical substance|chemical substance]] composed of many identical [[Physics:Molecule|molecule]]s (or [[Chemistry:Molecular entity|molecular entities]]) composed of [[Physics:Atom|atom]]s from more than one [[Chemistry:Chemical element|element]] held together by [[Chemistry:Chemical bond|chemical bond]]s. A [[Chemistry:Chemical element|chemical element]] bonded to an identical chemical element is not a chemical compound since only one element, not two different elements, is involved.}}
{{term|term= '''[[Chemistry:Chemical equilibrium|Chemical equilibrium]]'''}}{{defn|defn=In a [[Chemistry:Chemical reaction|chemical reaction]], '''chemical equilibrium''' is the state in which both reactants and products are present in [[Chemistry:Concentration|concentration]]s which have no further tendency to change with time, so that there is no observable change in the properties of the system.<ref name=Atkins>{{cite book |first1=Peter |last1=Atkins |first2=Julio |last2=De Paula |title=Atkins' Physical Chemistry |edition=8th |publisher=W. H. Freeman |date=2006 |isbn=978-0-7167-8759-4 |pages=[https://archive.org/details/atkinsphysicalch00pwat/page/200 200–202] |url=https://archive.org/details/atkinsphysicalch00pwat/page/200 }}</ref> Usually, this state results when the forward reaction proceeds at the same rate as the [[Physics:Reversible reaction|reverse reaction]]. The [[Physics:Reaction rate|reaction rate]]s of the forward and backward reactions are generally not zero, but equal. Thus, there are no net changes in the concentrations of the reactant(s) and product(s). Such a state is known as [[Physics:Dynamic equilibrium|dynamic equilibrium]].<ref name=aj>{{cite book|last1=Atkins |first1=Peter W. |last2=Jones |first2=Loretta |title=Chemical Principles: The Quest for Insight |edition=2nd |isbn=978-0-7167-9903-0|year=2008 }}</ref><ref>{{GoldBookRef|title=chemical equilibrium|file=C01023}}</ref>}}
{{term|term= '''[[Chemistry:Chemical kinetics|Chemical kinetics]]'''}}{{defn|defn='''Chemical kinetics''', also known as '''reaction kinetics''', is the study of [[Physics:Reaction rate|rates]] of [[Chemistry:Chemical process|chemical process]]es. Chemical kinetics includes investigations of how different experimental conditions can influence the speed of a [[Chemistry:Chemical reaction|chemical reaction]] and yield information about the [[Physics:Reaction mechanism|reaction's mechanism]] and [[Chemistry:Transition state|transition state]]s, as well as the construction of [[Mathematical model|mathematical model]]s that can describe the characteristics of a chemical reaction.}}
{{term|term= '''[[Chemistry:Chemical reaction|Chemical reaction]]'''}}{{defn|defn=A '''chemical reaction''' is a process that leads to the [[Chemistry:IUPAC nomenclature for organic transformations|chemical transformation]] of one set of [[Chemistry:Chemical substance|chemical substance]]s to another.<ref>{{GoldBookRef|title=chemical reaction|file=C01033}}</ref> Classically, chemical reactions encompass changes that only involve the positions of [[Physics:Electron|electron]]s in the forming and breaking of [[Chemistry:Chemical bond|chemical bond]]s between [[Physics:Atom|atom]]s, with no change to the nuclei (no change to the elements present), and can often be described by a [[Chemistry:Chemical equation|chemical equation]]. [[Chemistry:Nuclear chemistry|Nuclear chemistry]] is a sub-discipline of chemistry that involves the chemical reactions of unstable and radioactive elements where both electronic and nuclear changes can occur.}}
{{term|term= '''[[Chemistry:Chemistry|Chemistry]]'''}}{{defn|defn=Is the scientific discipline involved with [[Chemistry:Chemical element|elements]] and [[Chemistry:Chemical compound|compounds]] composed of [[Physics:Atom|atom]]s, [[Physics:Molecule|molecule]]s and [[Physics:Ion|ion]]s: their composition, structure, properties, behavior and the changes they undergo during a [[Chemistry:Chemical reaction|reaction]] with other [[Chemistry:Chemical substance|substances]].<ref>{{cite web|url=http://chemweb.ucc.ie/what_is_chemistry.htm |title=What is Chemistry? |publisher=Chemweb.ucc.ie |access-date=12 June 2011}}</ref><ref>{{cite web |title=Definition of CHEMISTRY |url=https://www.merriam-webster.com/dictionary/chemistry |website=www.merriam-webster.com |access-date=24 August 2020 }}</ref><ref>{{cite web |title=Definition of chemistry {{!}} Dictionary.com |url=http://dictionary.reference.com/browse/Chemistry |website=www.dictionary.com |access-date=24 August 2020 }}</ref><ref>{{Cite web|title=Chemistry Is Everywhere|url=https://www.acs.org/content/acs/en/education/whatischemistry/everywhere.html|website=[[Organization:American Chemical Society|American Chemical Society]]}}</ref>}}
{{term|term= '''[[Chemistry:Chloride|Chloride]]'''}}{{defn|defn=Any chemical compound containing the element chlorine.}} 
{{term|term= '''[[Chemistry:Chromate ion|Chromate]]'''}}{{defn|defn='''Chromate''' salts contain the chromate anion, {{chem|CrO|4|2−}}. '''Dichromate''' salts contain the dichromate anion, {{chem|Cr|2|O|7|2−}}. They are oxoanions of [[Chemistry:Chromium|chromium]] in the 6+ [[Chemistry:Oxidation state|oxidation state]] . They are moderately strong [[Chemistry:Oxidizing agent|oxidizing agent]]s. In an [[Chemistry:Aqueous|aqueous]] [[Chemistry:Solution|solution]], chromate and dichromate ions can be interconvertible.}}
{{term|term= '''[[Physics:Circular motion|Circular motion]]'''}}{{defn|defn=In [[Physics:Physics|physics]], circular motion is a movement of an object along the [[Circumference|circumference]] of a [[Circle|circle]] or [[Physics:Rotation|rotation]] along a circular path. It can be uniform, with constant angular rate of rotation and constant speed, or non-uniform with a changing rate of rotation. The [[Rotation around a fixed axis|rotation around a fixed axis]] of a three-dimensional body involves circular motion of its parts. The equations of motion describe the movement of the [[Physics:Center of mass|center of mass]] of a body.}}
{{term|term= '''[[Engineering:Civil engineering|Civil engineering]]'''}}{{defn|defn=The profession that deals with the design and construction of structures, or other fixed works.}}
{{term|term= '''[[Physics:Clausius–Clapeyron relation|Clausius–Clapeyron relation]]'''}}{{defn|defn=The '''Clausius–Clapeyron relation''', named after [[Biography:Rudolf Clausius|Rudolf Clausius]]<ref name="clausius">{{cite journal |last=Clausius |first=R. |title=Ueber die bewegende Kraft der Wärme und die Gesetze, welche sich daraus für die Wärmelehre selbst ableiten lassen |trans-title=On the motive power of heat and the laws which can be deduced therefrom regarding the theory of heat|journal=Annalen der Physik |volume=155 |issue= 4|pages=500–524 |year=1850 |url=http://gallica.bnf.fr/ark:/12148/bpt6k15164w/f518.image|doi=10.1002/andp.18501550403 |bibcode = 1850AnP...155..500C |language=de |hdl=2027/uc1.$b242250 |hdl-access=free }}</ref> and [[Biography:Benoît Paul Émile Clapeyron|Benoît Paul Émile Clapeyron]],<ref name="clapeyron">{{cite journal |last=Clapeyron |first=M. C. |url=http://gallica.bnf.fr/ark:/12148/bpt6k4336791/f157 |title=Mémoire sur la puissance motrice de la chaleur |journal=Journal de l'École Polytechnique |volume=23 |pages=153–190 |year=1834 |id=ark:/12148/bpt6k4336791/f157 |language=fr }}</ref> is a way of characterizing a discontinuous [[Physics:Phase transition|phase transition]] between two phases of matter of a single constituent. On a [[Physics:Pressure|pressure]]–[[Physics:Temperature|temperature]] (P–T) diagram, the line separating the two phases is known as the coexistence curve. The Clausius–Clapeyron relation gives the [[Slope|slope]] of the tangents to this curve. Mathematically,

:<math>\frac{\mathrm{d}P}{\mathrm{d}T} = \frac{L}{T\,\Delta v}=\frac{\Delta s}{\Delta v}, </math>

where <math>\mathrm{d}P/\mathrm{d}T</math> is the slope of the tangent to the coexistence curve at any point, <math>L</math> is the specific [[Physics:Latent heat|latent heat]], <math>T</math> is the [[Physics:Temperature|temperature]], <math>\Delta v </math> is the [[Specific volume|specific volume]] change of the phase transition, and <math>\Delta s </math> is the specific entropy change of the phase transition.}}
{{term|term= '''Clausius inequality'''}}{{defn|defn=.}}
{{term|term= '''[[Physics:Clausius theorem|Clausius theorem]]'''}}{{defn|defn=The '''Clausius theorem''' (1855) states that a system exchanging heat with external reservoirs and undergoing a cyclic process, is one that ultimately returns a system to its original state,

:<math>\oint \frac{\delta Q}{T_{surr}} \leq 0,</math>

where <math>\delta Q</math> is the infinitesimal amount of heat absorbed by the system from the reservoir and <math>T_{surr}</math> is the [[Physics:Temperature|temperature]] of the external reservoir (surroundings) at a particular instant in time. In the special case of a reversible process, the equality holds.<ref>[http://scienceworld.wolfram.com/physics/ClausiusTheorem.html '''Clausius theorem'''] at [[Company:Wolfram Research|Wolfram Research]]</ref> The reversible case is used to introduce the [[Physics:Entropy|entropy]] state function. This is because in a cyclic process the variation of a state function is zero. In words, the Clausius statement states that it is impossible to construct a device whose sole effect is the transfer of heat from a cool reservoir to a hot reservoir.<ref>Finn, Colin B. P. ''Thermal Physics''. 2nd ed., CRC Press, 1993.</ref> Equivalently, heat spontaneously flows from a hot body to a cooler one, not the other way around.<ref>Giancoli, Douglas C. ''Physics: Principles with Applications''. 6th ed., Pearson/Prentice Hall, 2005.</ref> The generalized "inequality of Clausius"<ref>Mortimer, R. G. ''Physical Chemistry''. 3rd ed., p. 120, Academic Press, 2008.</ref>

:<math>dS > \frac{\delta Q}{T_{surr}} </math>

for an infinitesimal change in entropy ''S'' applies not only to cyclic processes, but to any process that occurs in a closed system. }}
{{term|term= '''[[Engineering:Coefficient of performance|Coefficient of performance]]'''}}{{defn|defn=The '''coefficient of performance''' or '''COP''' (sometimes '''CP''' or '''CoP''') of a [[Physics:Heat pump and refrigeration cycle|heat pump, refrigerator or air conditioning system]] is a ratio of useful heating or cooling provided to work required.<ref>{{cite web |url=http://www.tetech.com/temodules/graphs/instructions.pdf |title=Archived copy |access-date=2013-10-16 |url-status=dead |archive-url=https://web.archive.org/web/20130124080037/http://www.tetech.com/temodules/graphs/instructions.pdf |archive-date=2013-01-24 }}</ref><ref>{{Cite web | url=http://us.grundfos.com/service-support/encyclopedia-search/cop-coefficient-ofperformance.html | title=COP (Coefficient of performance)}}</ref> Higher COPs equate to lower operating costs. The COP usually exceeds 1, especially in heat pumps, because, instead of just converting work to heat (which, if 100% efficient, would be a COP_hp of 1), it pumps additional heat from a heat source to where the heat is required. For complete systems, COP calculations should include energy consumption of all power consuming auxiliaries. COP is highly dependent on operating conditions, especially absolute temperature and relative temperature between sink and system, and is often graphed or averaged against expected conditions.<ref>{{cite web |url=http://www.tetech.com/temodules/graphs/HP-199-1.4-0.8.pdf |title=Archived copy |access-date=2013-10-16 |url-status=dead |archive-url=https://web.archive.org/web/20090107132318/http://www.tetech.com/temodules/graphs/HP-199-1.4-0.8.pdf |archive-date=2009-01-07 }}</ref>}} 
{{term|term= '''[[Coefficient of variation]]'''}}{{defn|defn=In [[Probability theory|probability theory]] and [[Statistics|statistics]], the '''coefficient of variation''' ('''CV'''), also known as '''relative standard deviation''' ('''RSD'''), is a standardized measure of [[Statistical dispersion|dispersion]] of a [[Probability distribution|probability distribution]] or [[Frequency distribution|frequency distribution]]. It is often expressed as a percentage, and is defined as the ratio of the [[Standard deviation|standard deviation]]  <math>\ \sigma </math> to the [[Mean|mean]]  <math>\ \mu </math> (or its [[Absolute value|absolute value]], <math>| \mu |</math>).}}
{{term|term= '''[[Physics:Coherence|Coherence]]'''}}{{defn|defn=In [[Physics:Physics|physics]], two wave sources are perfectly coherent if they have a constant phase difference and the same [[Physics:Frequency|frequency]], and the same [[Waveform|waveform]]. Coherence is an ideal property of [[Wave|wave]]s that enables stationary (i.e. temporally and spatially constant) interference. It contains several distinct concepts, which are limiting cases that never quite occur in reality but allow an understanding of the physics of waves, and has become a very important concept in quantum physics. More generally, '''coherence''' describes all properties of the [[Correlation function|correlation]] between physical quantities of a single wave, or between several waves or wave packets.}}
{{term|term= '''[[Chemistry:Cohesion|Cohesion]]'''}}{{defn|defn=Or '''cohesive attraction''' or '''cohesive force''' is the action or [[Chemistry:Chemical property|property]] of like [[Physics:Molecule|molecule]]s sticking together, being mutually attractive. It is an intrinsic property of a [[Chemistry:Chemical substance|substance]] that is caused by the shape and structure of its molecules, which makes the distribution of orbiting [[Physics:Electron|electron]]s irregular when molecules get close to one another, creating [[Physics:Coulomb force|electrical attraction]] that can maintain a microscopic structure such as a [[Physics:Drop (liquid)|water drop]]. In other words, cohesion allows for [[Physics:Surface tension|surface tension]], creating a "solid-like" state upon which light-weight or low-density materials can be placed.}}
{{term|term= '''Cold forming'''}}{{defn|defn=Or '''cold working''', any metal-working procedure (such as hammering, rolling, shearing, bending, milling, etc.) carried out below the metal's recrystallization temperature.}}
{{term|term= '''[[Physics:Combustion|Combustion]]'''}}{{defn|defn=Or '''burning''',<ref>colloquial meaning of burning is combustion accompanied by flames</ref> is a high-temperature exothermic [[Chemistry:Redox|redox]] [[Chemistry:Chemical reaction|chemical reaction]] between a fuel (the reductant) and an oxidant, usually atmospheric [[Chemistry:Oxygen|oxygen]], that produces oxidized, often gaseous products, in a mixture termed as [[Earth:Smoke|smoke]].}}
{{term|term= '''[[Engineering:Compensation (engineering)|Compensation]]'''}}{{defn|defn=Is planning for side effects or other unintended issues in a [[Design|design]]. In a more simpler term, it's a "counter-procedure" plan on expected side effect performed to produce more efficient and useful results. The design of an [[Invention|invention]] can itself also be to compensate for some other existing issue or [[Philosophy:Action|exception]].}}
{{term|term= '''[[Compiler]]'''}}{{defn|defn=A computer program that translates a high-level language into machine language.}} 
{{term|term= '''[[Engineering:Compressive strength|Compressive strength]]'''}}{{defn|defn='''Compressive strength''' or '''compression strength''' is the capacity of a material or structure to withstand loads tending to reduce size, as opposed to [[Physics:Ultimate tensile strength|tensile strength]], which withstands loads tending to elongate. In other words, compressive strength resists [[Physics:Compression|compression]] (being pushed together), whereas tensile strength resists [[Physics:Tension|tension]] (being pulled apart). In the study of [[Physics:Strength of materials|strength of materials]], tensile strength, compressive strength, and [[Engineering:Shear strength|shear strength]] can be analyzed independently.}}
{{term|term= '''[[Computational fluid dynamics]]'''}}{{defn|defn=The numerical solution of flow equations in practical problems such as aircraft design or hydraulic structures.}}
{{term|term= '''[[Computer]]'''}}{{defn|defn=A '''computer''' is a device that can be instructed to carry out sequences of [[Arithmetic|arithmetic]] or [[Boolean algebra|logical]] operations automatically via [[Computer programming|computer programming]]. Modern computers have the ability to follow generalized sets of operations, called ''[[Computer program|programs]].'' These programs enable computers to perform an extremely wide range of tasks.}}
{{term|term= '''[[Engineering:Computer-aided design|Computer-aided design]]'''}}{{defn|defn='''Computer-aided design''' ('''CAD''') is the use of computer systems (or {{vanchor|[[Workstation|workstation]]s|WORKSTATION}}) to aid in the creation, modification, analysis, or optimization of a [[Design|design]].<ref>{{cite book|last=Narayan|first=K. Lalit|title=Computer Aided Design and Manufacturing|year=2008|publisher=Prentice Hall of India|location=New Delhi|page=3|url=https://books.google.com/books?id=zXdivq93WIUC|isbn=978-8120333420}}</ref> CAD software is used to increase the productivity of the designer, improve the quality of design, improve communications through documentation, and to create a database for manufacturing.<ref>{{cite book|last=Narayan|first=K. Lalit|title=Computer Aided Design and Manufacturing|year=2008|publisher=Prentice Hall of India|location=New Delhi|page=4|url=https://books.google.com/books?id=zXdivq93WIUC|isbn=978-8120333420}}</ref> CAD output is often in the form of electronic files for print, machining, or other manufacturing operations. The term '''CADD''' (for ''Computer Aided Design and Drafting'') is also used.<ref>{{cite book|last=Duggal |first=Vijay |year=2000 |title=Cadd Primer: A General Guide to Computer Aided Design and Drafting-Cadd, CAD |isbn=978-0962916595 |publisher=Mailmax Pub}}</ref>}} 
{{term|term= '''[[Computer-aided engineering]]'''}}{{defn|defn='''Computer-aided engineering''' ('''CAE''') is the broad usage of computer software to aid in [[Engineering:Engineering|engineering]] analysis tasks. It includes {{nowrap|finite element analysis (FEA)}}, {{nowrap|[[Computational fluid dynamics|computational fluid dynamics]] (CFD)}}, {{nowrap|multibody dynamics (MBD)}}, [[Physics:Durability|durability]] and optimization.}}
{{term|term= '''[[Computer-aided manufacturing]]'''}}{{defn|defn='''Computer-aided manufacturing''' ('''CAM''') is the use of  software to control [[Engineering:Machine tool|machine tool]]s and related ones in the manufacturing of workpieces.<ref name="ota">{{cite book | last = U.S. Congress, [[Engineering:Office of Technology Assessment|Office of Technology Assessment]] | title = Computerized manufacturing automation | page = 48 | publisher= DIANE Publishing | year = 1984 | url = https://books.google.com/books?id=LYdF5akRL6sC&pg=PA48 | isbn = 978-1-4289-2364-5}}</ref><ref>{{Citation | last1 = Hosking | first1 = Dian Marie | last2 = Anderson | first2 = Neil | title = Organizational change and innovation | page = 240 | publisher = Taylor & Francis | year = 1992 | url = https://books.google.com/books?id=TbwOAAAAQAAJ&pg=PA240 | isbn = 978-0-415-06314-2}}</ref><ref name="daintith">{{cite book | last = Daintith | first = John | title = A dictionary of computing | page = 102 | publisher = Oxford University Press | year = 2004 | edition = 5 | url = https://books.google.com/books?id=Hay6vTsGFAsC&pg=PA102 | isbn = 978-0-19-860877-6}}</ref><ref>{{cite book| last = Kreith | first = Frank |  title = The CRC handbook of mechanical engineering | page = 15-1<!-- Not a range. --> | publisher = CRC Press | year = 1998| url = https://books.google.com/books?id=OpD226SXKisC&pg=PT1972 | isbn = 978-0-8493-9418-8 }}</ref><ref>{{cite book | last = Matthews | first = Clifford | title = Aeronautical engineer's data book | page = 229 | publisher = Butterworth-Heinemann | year = 2005 | edition = 2nd | url = https://books.google.com/books?id=5W9Rqq3qP1QC| isbn = 978-0-7506-5125-7}}</ref> This is not the only definition for CAM, but it is the most common;<ref name="ota"/> CAM may also refer to the use of a computer to assist in all operations of a manufacturing plant, including planning, management, transportation and storage.<ref>{{cite book| last1 = Pichler | first1 = Franz | last2 = Moreno-Díaz | first2 = Roberto | title = Computer aided systems theory | page = 602 | publisher = Springer | year = 1992 | url = https://books.google.com/books?id=xmHL8KONTXUC&pg=PA602 | isbn = 978-3-540-55354-0}}</ref><ref>{{cite book | last1 = Boothroyd | first1 = Geoffrey | last2 = Knight | first2 = Winston Anthony | title = Fundamentals of machining and machine tools | page = 401 | publisher = CRC Press | year = 2006 | edition = 3rd | url = https://books.google.com/books?id=Y0cRCFalmekC&pg=PA401 | isbn = 978-1-57444-659-3}}</ref>}}
{{term|term= '''[[Computer engineering]]'''}}{{defn|defn='''Computer engineering''' is a [[Discipline (academia)|discipline]] that integrates several fields of [[Computer science|computer science]] and electronics engineering required to develop computer hardware and software.<ref>{{Cite book
 | last = IEEE Computer Society
 | title = Computer Engineering 2004: Curriculum Guidelines for Undergraduate Degree Programs in Computer Engineering
 | url = http://www.acm.org/education/education/curric_vols/CE-Final-Report.pdf
 | access-date = December 17, 2012
 |date=December 12, 2004
 | page = iii
 | quote = Computer System engineering has traditionally been viewed as a combination of both electronic engineering (EE) and computer science (CS).
}}</ref>}}
{{term|term= '''[[Computer science]]'''}}{{defn|defn=Is the theory, experimentation, and engineering that form the basis for the design and use of [[Computer|computer]]s. It involves the study of [[Algorithm|algorithm]]s that process, store, and communicate [[Digital data|digital]] [[Information|information]]. A [[Computer scientist|computer scientist]] specializes in the theory of computation and the design of computational systems.<ref>{{cite web |url=http://wordnetweb.princeton.edu/perl/webwn?s=computer%20scientist |title=WordNet Search—3.1 |publisher=Wordnetweb.princeton.edu |access-date=14 May 2012}}</ref>}} 
{{term|term= '''Concave lens'''}}{{defn|defn=Lenses are classified by the curvature of the two optical surfaces. A lens is ''biconvex'' (or ''double convex'', or just ''convex'') if both surfaces are convex. If both surfaces have the same radius of curvature, the lens is ''equiconvex''. A lens with two concave surfaces is ''biconcave'' (or just ''concave''). If one of the surfaces is flat, the lens is ''plano-convex'' or ''plano-concave'' depending on the curvature of the other surface. A lens with one convex and one concave side is ''convex-concave'' or ''meniscus''.}}
{{term|term= '''[[Physics:Condensed matter physics|Condensed matter physics]]'''}}{{defn|defn=Is the field of physics that deals with the macroscopic and microscopic physical properties of matter. In particular it is concerned with the "condensed" phases that appear whenever the number of constituents in a system is extremely large and the interactions between the constituents are strong.}}
{{term|term= '''[[Confidence interval]]'''}}{{defn|defn=In statistics, a '''confidence interval''' or '''compatibility interval''' ('''CI''') is a type of interval estimate, computed from the statistics of the observed data, that might contain the true value of an unknown population parameter. The interval has an associated '''confidence level''' that, loosely speaking, quantifies the level of confidence that the parameter lies in the interval. More strictly speaking, the '''confidence level''' represents the frequency (i.e. the proportion) of possible confidence intervals that contain the true value of the unknown population parameter. In other words, if confidence intervals are constructed using a given confidence level from an infinite number of independent sample statistics, the proportion of those intervals that contain the true value of the parameter will be equal to the confidence level.<ref name=CH>Cox D.R., Hinkley D.V. (1974) ''Theoretical Statistics'', Chapman & Hall, p49, p209</ref><ref name=KS>Kendall, M.G. and Stuart, D.G. (1973) ''The Advanced Theory of Statistics''. Vol 2: Inference and Relationship, Griffin, London. Section 20.4</ref><ref name=Neyman>{{cite journal | last1 = Neyman | first1 = J. |  year = 1937 | title = Outline of a Theory of Statistical Estimation Based on the Classical Theory of Probability | jstor = 91337 | journal = Philosophical Transactions of the Royal Society A | volume = 236 | issue = 767| pages = 333–380 | doi=10.1098/rsta.1937.0005| bibcode = 1937RSPTA.236..333N | doi-access = free }}</ref>}}
{{term|term= '''[[Chemistry:Conjugate acid|Conjugate acid]]'''}}{{defn|defn=A '''conjugate acid''', within the [[Chemistry:Brønsted–Lowry acid–base theory|Brønsted–Lowry acid–base theory]], is a [[Chemistry:Chemical species|species]] formed by the [[Chemistry:Protonation|reception of a proton]] ([[Chemistry:Hydron|H<sup>+</sup>]]) by a [[Chemistry:Base|base]]—in other words, it is a base with a [[Chemistry:Hydrogen|hydrogen]] ion added to it. On the other hand, a '''conjugate base''' is what is left over after an acid has donated a proton during a chemical reaction. Hence, a conjugate base is a species formed by the [[Chemistry:Deprotonation|removal of a proton]] from an acid.<ref name="Zumdahl, Stephen S. 2007" /> Because some acids are capable of releasing multiple protons, the conjugate base of an acid may itself be acidic.}}
{{term|term= '''Conjugate base'''}}{{defn|defn=A '''conjugate acid''', within the [[Chemistry:Brønsted–Lowry acid–base theory|Brønsted–Lowry acid–base theory]], is a [[Chemistry:Chemical species|species]] formed by the [[Chemistry:Protonation|reception of a proton]] ([[Chemistry:Hydron|H<sup>+</sup>]]) by a [[Chemistry:Base|base]]—in other words, it is a base with a [[Chemistry:Hydrogen|hydrogen]] ion added to it. On the other hand, a '''conjugate base''' is what is left over after an acid has donated a proton during a chemical reaction. Hence, a conjugate base is a species formed by the [[Chemistry:Deprotonation|removal of a proton]] from an acid.<ref name="Zumdahl, Stephen S. 2007">Zumdahl, Stephen S., & Zumdahl, Susan A. ''Chemistry''. Houghton Mifflin, 2007, {{ISBN|0618713700}}</ref> Because some acids are capable of releasing multiple protons, the conjugate base of an acid may itself be acidic.}}
{{term|term= '''[[Physics:Conservation of energy|Conservation of energy]]'''}}{{defn|defn=In physics and chemistry, the '''law of conservation of energy''' states that the total [[Physics:Energy|energy]] of an [[Physics:Isolated system|isolated system]] remains constant; it is said to be [[Conservation law|''conserved'']] over time.<ref name=Feynman2Ch1S2>{{cite book |author=Richard Feynman |title=The Feynman Lectures on Physics Vol I |publisher=Addison Wesley |year=1970 |isbn=978-0-201-02115-8 |url=http://www.feynmanlectures.caltech.edu/I_04.html}}</ref> This law means that energy can neither be created nor destroyed; rather, it can only be transformed or transferred from one form to another.}}
{{term|term= '''[[Physics:Conservation of mass|Conservation of mass]]'''}}{{defn|defn=The '''law of conservation of mass''' or '''principle of mass conservation''' states that for any [[Closed system|system closed]] to all transfers of [[Physics:Matter|matter]] and [[Physics:Energy|energy]], the [[Physics:Mass|mass]] of the system must remain constant over time, as system's mass cannot change, so quantity cannot be added nor removed. Hence, the quantity of mass is conserved over time.}}
{{term|term= '''[[Continuity equation]]'''}}{{defn|defn=A '''continuity equation''' in physics is an [[Equation|equation]] that describes the transport of some quantity. It is particularly simple and powerful when applied to a [[Conserved quantity|conserved quantity]], but it can be generalized to apply to any [[Physics:Intensive and extensive properties|extensive quantity]]. Since [[Physics:Mass|mass]], [[Physics:Energy|energy]], [[Physics:Momentum|momentum]], [[Physics:Electric charge|electric charge]] and other natural&nbsp;quantities are conserved under their respective appropriate conditions, a variety of physical phenomena may be described using continuity equations.}}
{{term|term= '''[[Physics:Continuum mechanics|Continuum mechanics]]'''}}{{defn|defn= Is a branch of [[Physics:Mechanics|mechanics]] that deals with the mechanical behavior of materials modeled as a continuous mass rather than as discrete particles. The French mathematician [[Biography:Augustin-Louis Cauchy|Augustin-Louis Cauchy]] was the first to formulate such models in the 19th century.}}
{{term|term= '''Control engineering'''}}{{defn|defn='''Control engineering''' or '''control systems engineering'''  is an [[Engineering:Engineering|engineering]] discipline that applies automatic control theory to design systems with desired behaviors in [[Control theory|control]] environments.<ref name="Case Western Reserve University">{{cite web|title=Systems & Control Engineering FAQ {{!}} Electrical Engineering and Computer Science|url=https://engineering.case.edu/eecs/node/213|website=engineering.case.edu|publisher=Case Western Reserve University|access-date=27 June 2017|language=en|date=20 November 2015}}</ref> The discipline of controls overlaps and is usually taught along with [[Electrical engineering|electrical engineering]] at many institutions around the world.<ref name="Case Western Reserve University"/>
.}}
{{term|term= '''Convex lens'''}}{{defn|defn=Lenses are classified by the curvature of the two optical surfaces. A lens is ''biconvex'' (or ''double convex'', or just ''convex'') if both surfaces are convex. If both surfaces have the same radius of curvature, the lens is ''equiconvex''. A lens with two concave surfaces is ''biconcave'' (or just ''concave''). If one of the surfaces is flat, the lens is ''plano-convex'' or ''plano-concave'' depending on the curvature of the other surface. A lens with one convex and one concave side is ''convex-concave'' or ''meniscus''.}}
{{term|term= '''[[Chemistry:Corrosion|Corrosion]]'''}}{{defn|defn=Is a [[Earth:Erosion|natural process]], which converts a refined metal to a more chemically-stable form, such as its [[Chemistry:Oxide|oxide]], [[Chemistry:Hydroxide|hydroxide]], or [[Chemistry:Sulfide|sulfide]]. It is the gradual destruction of materials (usually [[Chemistry:Metal|metal]]s) by chemical and/or electrochemical reaction with their environment. [[Chemistry:Corrosion engineering|Corrosion engineering]] is the field dedicated to controlling and stopping corrosion.}}
{{term|term= '''Cosmic rays'''}}{{defn|defn='''Cosmic rays''' are [[Physics:Ionizing radiation|high-energy radiation]], mainly originating outside the [[Astronomy:Solar System|Solar System]].<ref>{{cite book
 | last=Sharma
 | title=Atomic And Nuclear Physics
 | date=2008
 | publisher=Pearson Education India
 | isbn=978-81-317-1924-4
 | page=478
}}</ref>}}
{{term|term= '''[[Coulomb]]'''}}{{defn|defn=The '''coulomb''' (symbol: C) is the [[International System of Units]] (SI) unit of [[Physics:Electric charge|electric charge]]. It is the charge (symbol: ''Q'' or ''q'') transported by a constant current of one [[Ampere|ampere]] in one [[Second|second]]:
:<math>1 ~ \text{C} = 1 ~ \text{A} \cdot 1 ~ \text{s}</math>

Thus, it is also the amount of excess charge on a [[Engineering:Capacitor|capacitor]] of one [[Farad|farad]] charged to a potential difference of one [[Volt|volt]]:
:<math>1 ~ \text{C} = 1 ~ \text{F} \cdot 1 ~ \text{V}</math>

The coulomb is equivalent to the charge of approximately {{val|6.242|e=18}} ({{val|1.036|e=-5}} [[Mole (unit)|mol]]) [[Physics:Proton|proton]]s, and −1&nbsp;C is equivalent to the charge of approximately {{val|6.242|e=18}} [[Physics:Electron|electron]]s.

A new definition, in terms of the [[Physics:Elementary charge|elementary charge]], will take effect on 20 May 2019.<ref name=draft-resolution-A>
{{citation
 |title=Draft Resolution A "On the revision of the International System of units (SI)" to be submitted to the CGPM at its 26th meeting in November of 2018.
 |url=https://www.bipm.org/utils/en/pdf/CGPM/Draft-Resolution-A-EN.pdf
}}</ref> The new definition, defines the [[Physics:Elementary charge|elementary charge]] (the charge of the proton) as exactly {{val|1.602176634|e=-19}} coulombs. This would implicitly define the coulomb as {{frac|{{val|0.1602176634}}}}{{e|18}} elementary charges.}} 
{{term|term= '''[[Physics:Coulomb's law|Coulomb's law]]'''}}{{defn|defn='''Coulomb's law''', or '''Coulomb's inverse-square law''', is a [[Physical law|law]] of [[Physics:Physics|physics]] for quantifying Coulomb's force, or electrostatic force. Electrostatic force is the amount of force with which stationary, [[Physics:Electric charge|electrically charged]] particles either repel, or attract each other. This force and the law for quantifying it, represent one of the most basic forms of force used in the physical sciences, and were an essential basis to the study and development of the theory and field of [[Physics:Classical electromagnetism|classical electromagnetism]]. The law was first published in 1785 by French physicist [[Biography:Charles-Augustin de Coulomb|Charles-Augustin de Coulomb]].<ref>{{cite web| url=https://www.reference.com/science/electrostatic-force-explained-e59fd6cfe9ce6a6 | title=How is electrostatic force explained? | website=Reference* | year=2019 | publisher=IAC Publishing, LLC | access-date=January 5, 2019}}</ref>

In its [[Physics:Scalar|scalar]] form, the law is:

:<math>F=k_e\frac{q_1 q_2}{r^2}</math>,

where ''k''{{sub|''e''}} is [[Physics:Coulomb's constant|Coulomb's constant]] (''k''{{sub|''e''}} ≈ {{val|9e9|u=N m{{sup|2}} C{{sup|−2}}}}), ''q''{{sub|1}} and ''q''{{sub|2}} are the signed magnitudes of the charges, and the scalar ''r'' is the distance between the charges. The force of the interaction between the charges is attractive if the charges have opposite signs (i.e., ''F'' is negative) and repulsive if like-signed (i.e., ''F'' is positive).

Being an [[Inverse-square law|inverse-square law]], the law is analogous to [[Biography:Isaac Newton|Isaac Newton]]'s inverse-square [[Physics:Newton's law of universal gravitation|law of universal gravitation]]. Coulomb's law can be used to derive [[Physics:Gauss's law|Gauss's law]], and vice versa.}} 
{{term|term= '''[[Chemistry:Covalent bond|Covalent bond]]'''}}{{defn|defn=A '''covalent bond''', also called a '''molecular bond''', is a [[Chemistry:Chemical bond|chemical bond]] that involves the sharing of [[Physics:Electron pair|electron pair]]s between [[Physics:Atom|atom]]s.}}
{{term|term= '''[[Physics:Crookes tube|Crookes tube]]'''}}{{defn|defn=A type of vacuum tube that demonstrates cathode rays.}}
{{term|term= '''[[Physics:Cryogenics|Cryogenics]]'''}}{{defn|defn=The science of low temperatures.}}
{{term|term= '''[[Physics:Crystallization|Crystallization]]'''}}{{defn|defn='''Crystallization''' is the (natural or artificial) process by which a solid forms, where the atoms or molecules are highly organized into a structure known as a [[Earth:Crystal|crystal]]. Some of the ways by which crystals form are  [[Chemistry:Precipitation|precipitating]] from a [[Chemistry:Solution|solution]], [[Physics:Freezing|freezing]], or more rarely deposition directly from a [[Physics:Gas|gas]]. Attributes of the resulting crystal depend largely on factors such as temperature, air pressure, and in the case of liquid crystals, time of fluid evaporation.}} 
{{term|term= '''[[Physics:Crystallography|Crystallography]]'''}}{{defn|defn=The study of crystals.}} 
{{term|term= '''[[Physics:Curvilinear motion|Curvilinear motion]]'''}}{{defn|defn=Describes the motion of a moving particle that conforms to a known or fixed curve. The study of such motion involves the use of two co-ordinate systems, the first being planar motion and the latter being cylindrical motion.}} 
{{term|term= '''[[Physics:Cyclotron|Cyclotron]]'''}}{{defn|defn=A '''cyclotron''' is a type of [[Physics:Particle accelerator|particle accelerator]] invented by Ernest O. Lawrence in 1929-1930 at the [[Organization:University of California, Berkeley|University of California, Berkeley]],<ref>{{Cite web|url=http://www2.lbl.gov/Science-Articles/Archive/early-years.html|title=Ernest Lawrence's Cyclotron|website=www2.lbl.gov|access-date=2018-04-06}}</ref><ref>{{Cite web|url=https://www.nobelprize.org/nobel_prizes/physics/laureates/1939/lawrence-bio.html|title=Ernest Lawrence - Biographical|website=nobelprize.org|access-date=2018-04-06}}</ref> and patented in 1932.<ref name="Patent1948384">{{US patent|1948384}} Lawrence, Ernest O. ''Method and apparatus for the acceleration of ions'', filed: January 26, 1932, granted: February 20, 1934</ref><ref name="Lawrence">{{cite journal
 |last1 = Lawrence
 |first1 = Earnest O.
 |last2 = Livingston
 |first2 = M. Stanley
 |title = The Production of High Speed Light Ions Without the Use of High Voltages
 |journal = Physical Review
 |volume = 40
 |issue = 1
 |pages = 19–35
 |publisher = American Physical Society
 |date = April 1, 1932
 |doi = 10.1103/PhysRev.40.19
 | bibcode = 1932PhRv...40...19L
 |doi-access = free
 }}</ref> A cyclotron accelerates [[Physics:Charged particle|charged particle]]s outwards from the center along a spiral path.<ref name="Nave">{{cite web
 |last = Nave
 |first = C. R.
 |title = Cyclotron
 |publisher = Dept. of Physics and Astronomy, Georgia State University
 |date = 2012
 |url = http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/cyclot.html
 |access-date = October 26, 2014}}</ref><ref name=" Close">{{cite book
 |last1 = Close
 |first1 = F. E.
 |last2 = Close
 |first2 = Frank
 |last3 = Marten
 |first3 = Michael
 |title = The Particle Odyssey: A Journey to the Heart of Matter
 |publisher = Oxford University Press
 |date = 2004
 |pages = 84–87
 |url = https://books.google.com/books?id=PX87qqj5B2UC&pg=PA86
 |isbn = 978-0-19-860943-8
 |display-authors=0}}</ref> The particles are held to a spiral trajectory by a static magnetic field and accelerated by a rapidly varying ([[Engineering:Radio frequency|radio frequency]]) electric field. Lawrence was awarded the 1939 Nobel prize in physics for this invention.<ref name=" Close"/><ref>{{Cite web|url=https://www.nobelprize.org/nobel_prizes/physics/laureates/1939/lawrence-facts.html|title=Ernest Lawrence - Facts|website=nobelprize.org|access-date=2018-04-06}}</ref>}}
{{glossary end}}

==D==
{{glossary}}
{{term|term= '''[[Physics:Dalton's law|Dalton's law]]'''}}{{defn|defn=In [[Chemistry:Chemistry|chemistry]] and [[Physics:Physics|physics]], '''Dalton's law''' (also called '''Dalton's law of partial pressures''') states that in a mixture of non-reacting gases, the total  [[Physics:Pressure|pressure]] exerted is equal to the sum of the [[Physics:Partial pressure|partial pressure]]s of the individual gases.<ref name="Silberberg">{{cite book |last=Silberberg |first=Martin S. |date=2009 |title=Chemistry: the molecular nature of matter and change |url=https://archive.org/details/chemistrymolecul00silb_143 |url-access=limited |edition=5th |publisher=McGraw-Hill |location=Boston |isbn=9780073048598 |page=[https://archive.org/details/chemistrymolecul00silb_143/page/n234 206] |ref=1}}</ref>}}
{{term|term= '''Damped vibration'''}}{{defn|defn=Any vibration with a force acting against it to lessen the vibration over time.}} 
{{term|term= '''[[Darcy–Weisbach equation]]'''}}{{defn|defn= An equation used in fluid mechanics to find the pressure change cause by friction within a pipe or conduit.}}
{{term|term= '''[[Engineering:DC motor|DC motor]]'''}}{{defn|defn=An electrical motor driven by direct current.}}
{{term|term= '''[[Physics:Decibel|Decibel]]'''}}{{defn|defn=A logarithmic unit of ratios.}} 
{{term|term= '''Definite integral'''}}{{defn|defn=The integral of a [[Function (mathematics)|function]] between an upper and lower [[Limit (mathematics)|limit]].<ref>[https://en.wiktionary.org/wiki/definite_integral Wiktionary]</ref>}}
{{term|term= '''[[Engineering:Deflection (engineering)|Deflection]]'''}}{{defn|defn=Is the degree to which a structural element is displaced under a [[Physics:Force|load]]. It may refer to an angle or a distance.}}
{{term|term= '''[[Engineering:Deformation (engineering)|Deformation (engineering)]]'''}}{{defn|defn=In [[Physics:Materials science|materials science]], '''deformation''' refers to any changes in the shape or size of an object due to 
* an applied [[Physics:Force|force]] (the deformation energy in this case is transferred through work) or  
* a change in temperature (the deformation energy in this case is transferred through heat). 
The first case can be a result of [[Physics:Tensile strength|tensile]] (pulling) forces, [[Engineering:Compressive strength|compressive]] (pushing) forces, [[Physics:Simple shear|shear]], [[Physics:Bending|bending]] or [[Physics:Torsion (mechanics)|torsion]] (twisting).

In the second case, the most significant factor, which is determined by the temperature, is the mobility of the structural defects such as grain boundaries, point vacancies, line and screw dislocations, stacking faults and twins in both crystalline and non-crystalline solids. The movement or displacement of such mobile defects is thermally activated, and thus limited by the rate of atomic diffusion.<ref name="Dav">Davidge, R.W. (1979) ''Mechanical Behavior of Ceramics'', Cambridge Solid State Science Series, Eds. Clarke, D.R., et al.</ref><ref name="Zar">Zarzycki, J. (1991) ''Glasses and the Vitreous State'', Cambridge Solid State Science Series, Eds. Clarke, D.R., et al.</ref>}}
{{term|term= '''[[Physics:Deformation (mechanics)|Deformation (mechanics)]]'''}}{{defn|defn='''Deformation''' in [[Physics:Continuum mechanics|continuum mechanics]] is the transformation of a body from a ''reference'' configuration to a ''current'' configuration.<ref>{{cite book|last1=Truesdell |first1=C. |last2=Noll |first2=W. |year=2004 |title=The non-linear field theories of mechanics |url=https://archive.org/details/nonlinearfieldth00true_338 |url-access=limited |edition=3rd |publisher=Springer |page=[https://archive.org/details/nonlinearfieldth00true_338/page/n47 48]}}</ref> A configuration is a set containing the positions of all particles of the body.

A  deformation may be caused by [[Structural load|external loads]],<ref name=wu>{{cite book|first=H.-C. |last=Wu |title=Continuum Mechanics and Plasticity |publisher=CRC Press |date=2005 |isbn=978-1-58488-363-0}}</ref> [[Physics:Body force|body force]]s (such as [[Physics:Gravity|gravity]] or [[Physics:Electromagnetic force|electromagnetic force]]s), or changes in temperature, moisture content, or chemical reactions, etc.}}
{{term|term= '''[[Physics:Degrees of freedom (mechanics)|Degrees of freedom]]'''}}{{defn|defn=The number of parameters required to define the motion of a dynamical system.}} 
{{term|term= '''[[Delta robot]]'''}}{{defn|defn=A tripod linkage, used to construct fast-acting manipulators with a wide range of movement.}} 
{{term|term= '''[[Engineering:Delta-wye transformer|Delta-wye transformer]]'''}}{{defn|defn=A type of transformer used in three-phase power systems.}}
{{term|term= '''[[De Moivre–Laplace theorem]]'''}}{{defn|defn=In [[Probability theory|probability theory]], the '''de Moivre–Laplace theorem''', which is a special case of the [[Central limit theorem|central limit theorem]], states that the [[Normal distribution|normal distribution]] may be used as an approximation to the [[Binomial distribution|binomial distribution]] under certain conditions. In particular, the theorem shows that the [[Probability mass function|probability mass function]] of the random number of "successes" observed in a series of <math>n</math> independent [[Bernoulli trial]]s, each having probability <math>p</math> of success (a binomial distribution with <math>n</math> trials), converges to the [[Physics:Probability density function|probability density function]] of the normal distribution with mean <math>np</math> and standard deviation<math>\sqrt{np(1-p)}</math>, as <math>n</math> grows large, assuming <math>p</math> is not <math>0</math> or <math>1</math>.}} 
{{term|term= '''[[Physics:Density|Density]]'''}}{{defn|defn=
The '''density''', or more precisely, the '''volumetric mass density''', of a substance is its [[Physics:Mass|mass]] per unit [[Physics:Volume|volume]]. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' can also be used. Mathematically, density is defined as mass divided by volume:<ref>{{cite web | url =http://www.grc.nasa.gov/WWW/BGH/fluden.html | title =Gas Density Glenn research Center | author =''The National Aeronautic and Atmospheric Administration's'' ''[[Organization:Glenn Research Center|Glenn Research Center]]'' | publisher =grc.nasa.gov | url-status =dead | archive-url =https://web.archive.org/web/20130414132531/http://www.grc.nasa.gov/WWW/BGH/fluden.html | archive-date =April 14, 2013 | df =mdy-all | access-date =March 31, 2019 }}</ref>

:<math> \rho = \frac{m}{V}</math>

where ''ρ'' is the density, ''m'' is the mass, and ''V'' is the volume. In some cases (for instance, in the United States oil and gas industry), density is loosely defined as its [[Physics:Weight|weight]] per unit [[Physics:Volume|volume]],<ref>{{cite web|url=http://oilgasglossary.com/density.html |title=Density definition in Oil Gas Glossary |publisher=Oilgasglossary.com |access-date=September 14, 2010 |url-status=dead |archive-url=https://web.archive.org/web/20100805010226/http://oilgasglossary.com/density.html |archive-date=August 5, 2010 }}</ref> although this is scientifically inaccurate – this quantity is more specifically called [[Physics:Specific weight|specific weight]].}} 
{{term|term= '''[[Derivative]]'''}}{{defn|defn=The '''derivative''' of a [[Function of a real variable|function of a real variable]] measures the sensitivity to change of the function value (output value) with respect to a change in its argument (input value). Derivatives are a fundamental tool of [[Calculus|calculus]]. For example, the derivative of the position of a moving object with respect to [[Time|time]] is the object's [[Physics:Velocity|velocity]]: this measures how quickly the position of the object changes when time advances.}}
{{term|term= '''Design engineering'''}}{{defn|defn=.}}
{{term|term= '''[[Physics:Dew point|Dew point]]'''}}{{defn|defn= The pressure and temperature at which air is holding the maximum possible humidity.}}
{{term|term= '''[[Physics:Diamagnetism|Diamagnetism]]'''}}{{defn|defn='''Diamagnetic''' materials are repelled by a [[Physics:Magnetic field|magnetic field]]; an applied magnetic field creates an induced magnetic field in them in the opposite direction, causing a repulsive force. In contrast, [[Physics:Paramagnetic|paramagnetic]] and [[Physics:Ferromagnetic|ferromagnetic]] materials are attracted by a magnetic field. '''Diamagnetism''' is a [[Physics:Quantum mechanical|quantum mechanical]] effect that occurs in all materials; when it is the only contribution to the magnetism, the material is called diamagnetic. In paramagnetic and ferromagnetic substances the weak diamagnetic force is overcome by the attractive force of [[Physics:Magnetic dipole|magnetic dipole]]s in the material. The [[Physics:Permeability (electromagnetism)|magnetic permeability]] of diamagnetic materials is less than μ<sub>0</sub>, the permeability of vacuum. In most materials diamagnetism is a weak effect which can only be detected by sensitive laboratory instruments, but a [[Physics:Superconductivity|superconductor]] acts as a strong diamagnet because it repels a magnetic field entirely from its interior.}}
{{term|term= '''[[Physics:Dielectric|Dielectric]]'''}}{{defn|defn=An insulator, a material that does not permit free flow of electricity.}}
{{term|term= '''[[Physics:Pressure measurement#Absolute, gauge and differential pressures — zero reference|Differential pressure]]'''}}{{defn|defn=.}}
{{term|term= '''[[Physics:Differential pulley|Differential pulley]]'''}}{{defn|defn=A '''differential pulley''', also called '''Weston differential pulley''',  or colloquially '''chain fall''', is used to manually lift very heavy objects like [[Earth:Internal combustion engine|car engines]]. It is operated by pulling upon the slack section of a continuous chain that wraps around pulleys. The relative size of two connected pulleys determines the maximum weight that can be lifted by hand. The load will remain in place (and not lower under the force of [[Physics:Gravity|gravity]]) until the chain is pulled.<ref>{{cite book |last1=Macauley |first1=David |last2=Ardley |first2=Neil |title=The New Way Things Work |page=[https://archive.org/details/newwaythingswork00maca/page/56 56] |publisher=Houghton Mifflin Company |location=Boston, USA |year=1998 |isbn=978-0-395-93847-8 |url=https://archive.org/details/newwaythingswork00maca/page/56 }}</ref>}}
{{term|term= '''[[Engineering:Differential signaling|Differential signaling]]'''}}{{defn|defn=Is a method for electrically transmitting [[Information|information]] using two complementary signals.}}
{{term|term= '''[[Physics:Diffusion|Diffusion]]'''}}{{defn|defn=Is the net movement of molecules or atoms from a region of higher concentration (or high chemical potential) to a region of lower concentration (or low chemical potential).}}
{{term|term= '''[[Dimensional analysis]]'''}}{{defn|defn=is the analysis of the relationships between different physical quantities by identifying their [[Physics:Base quantity|base quantities]] (such as [[Physics:Length|length]], [[Physics:Mass|mass]], [[Time|time]], and [[Physics:Electric charge|electric charge]]) and units of measure (such as miles vs. kilometers, or pounds vs. kilograms) and tracking these dimensions as calculations or comparisons are performed. The [[Conversion of units|conversion of units]] from one dimensional unit to another is often somewhat complex. Dimensional analysis, or more specifically the '''factor-label method''', also known as the '''unit-factor method''', is a widely used technique for such conversions using the rules of [[Algebra|algebra]].<ref>{{cite book|first=David |last=Goldberg|title=Fundamentals of Chemistry|edition=5th |publisher=McGraw-Hill|year=2006|isbn=978-0-07-322104-5}}</ref><ref>{{cite book|first=James |last=Ogden|title=The Handbook of Chemical Engineering|publisher=Research & Education Association|year=1999|isbn=978-0-87891-982-6}}</ref><ref>{{cite web |url=http://www.kentchemistry.com/links/Measurements/dimensionalanalysis.htm |title=Dimensional Analysis or the Factor Label Method |website=Mr Kent's Chemistry Page}}</ref>}}
{{term|term= '''[[Direct integration of a beam]]'''}}{{defn|defn='''Direct integration''' is a [[Structural analysis|structural analysis]] method for measuring internal shear, internal moment, rotation, and deflection of a beam.

For a beam with an applied weight <math>w(x) </math>, taking downward to be positive, the internal [[Physics:Shear force|shear force]] is given by taking the negative integral of the weight:
: <math>V(x) = -\int w(x)\, dx</math>
The internal moment M(x) is the integral of the internal shear:
: <math>M(x) = \int V(x)\, dx</math> = <math> -\int [\int w(x)\ \, dx] dx </math>

The [[Angle of rotation|angle of rotation]] from the horizontal, <math> \theta</math>, is the integral of the internal moment divided by the product of the [[Physics:Young's modulus|Young's modulus]] and the [[Second moment of area|area moment of inertia]]:
: <math>\theta (x) = \frac{1}{EI} \int M(x)\, dx </math>

Integrating the angle of rotation obtains the vertical displacement <math> \nu </math>:
: <math>\nu (x) = \int \theta (x) dx </math>.}}
{{term|term= '''[[Physics:Dispersion (optics)|Dispersion]]'''}}{{defn|defn=In [[Physics:Optics|optics]], '''dispersion''' is the phenomenon in which the [[Physics:Phase velocity|phase velocity]] of a wave depends on its frequency.<ref>{{cite book
|last1= Born
|first1= Max
|last2= Wolf
|first2= Emil
|title= [[Physics:Principles of Optics|Principles of Optics]]
|publisher= {{wipe|Cambridge University Press}}
|date= October 1999
|location= Cambridge
|pages= [https://archive.org/details/principlesoptics00born_100/page/n37 14]–24
|isbn= 978-0-521-64222-4}}</ref>
Media having this common property may be termed ''dispersive media''. Sometimes the term '''''chromatic'' dispersion''' is used for specificity.
Although the term is used in the field of optics to describe [[Physics:Light|light]] and other electromagnetic waves, dispersion in the same sense can apply to any sort of wave motion such as [[Physics:Acoustic dispersion|acoustic dispersion]] in the case of sound and seismic waves, in [[Gravity wave|gravity wave]]s (ocean waves), and for telecommunication signals along [[Engineering:Transmission line|transmission line]]s (such as [[Engineering:Coaxial cable|coaxial cable]]) or [[Engineering:Optical fiber|optical fiber]].}}
{{term|term= '''[[Physics:Displacement (fluid)|Displacement (fluid)]]'''}}{{defn|defn=In [[Physics:Fluid mechanics|fluid mechanics]], '''displacement''' occurs when an object is immersed in a [[Physics:Fluid|fluid]], pushing it out of the way and taking its place. The volume of the fluid displaced can then be measured, and from this, the volume of the immersed object can be deduced (the volume of the immersed object will be exactly equal to the volume of the displaced fluid).}}
{{term|term= '''[[Displacement (vector)]]'''}}{{defn|defn=Is a [[Euclidean vector|vector]] whose length is the shortest [[Distance|distance]] from the initial to the final [[Position (vector)|position]] of a point P.<ref>{{cite web|url=http://www.physicsclassroom.com/Class/1DKin/U1L1c.cfm|title=Describing Motion with Words|author=Tom Henderson|work=The Physics Classroom|access-date=2 January 2012}}</ref> It quantifies both the distance and direction of an imaginary motion along a straight line from the initial position to the final position of the point. A displacement may be identified with the [[Translation (geometry)|translation]] that maps the initial position to the final position.}}
{{term|term= '''[[Distance]]'''}}{{defn|defn=is a numerical [[Measurement|measurement]] of how far apart objects are.}}
{{term|term= '''[[Physics:Doppler effect|Doppler effect]]'''}}{{defn|defn=The '''Doppler effect''' (or the '''Doppler shift''') is the change in [[Physics:Frequency|frequency]] or [[Wavelength|wavelength]] of a [[Wave|wave]] in relation to an [[Physics:Observer|observer]] who is moving relative to the wave source.<ref name="Giordano">{{cite book
 | last1 = Giordano
 | first1 = Nicholas
 | title = College Physics: Reasoning and Relationships
 | publisher = Cengage Learning
 | date = 2009
 | pages = 421–424
 | url = https://books.google.com/books?id=BwistUlpZ7cC&pg=PA424
 | isbn = 978-0534424718
 }}</ref> It is named after the Austrian physicist [[Biography:Christian Doppler|Christian Doppler]], who described the phenomenon in 1842.}}
{{term|term= '''[[Chemistry:Dose–response relationship|Dose–response relationship]]'''}}{{defn|defn=The dose–response relationship, or exposure–response relationship, describes the magnitude of the [[Philosophy:Stimulus–response model|response]] of an organism, as a [[Function (mathematics)|function]] of exposure (or [[Chemistry:Dose (biochemistry)|doses]]) to a [[Biology:Stimulus (physiology)|stimulus]] or [[Biology:Stressor|stressor]] (usually a chemical) after a certain exposure time.<ref>{{cite journal |last1=Crump |first1=K. S. |last2=Hoel |first2=D. G. |last3=Langley |first3=C. H. |last4=Peto |first4=R. |title=Fundamental Carcinogenic Processes and Their Implications for Low Dose Risk Assessment |journal=Cancer Research |date=1 September 1976 |volume=36 |issue=9 Part 1 |pages=2973–2979 |pmid=975067 |url=http://cancerres.aacrjournals.org/content/36/9_Part_1/2973.long }}</ref> Dose–response relationships can be described by dose–response curves. A stimulus response function or stimulus response curve is defined more broadly as the response from any type of stimulus, not limited to chemicals. }}
{{term|term= '''[[Physics:Drag|Drag]]'''}}{{defn|defn=In [[Physics:Fluid dynamics|fluid dynamics]], '''drag''' (sometimes called '''air resistance''', a type of [[Physics:Friction|friction]], or '''fluid resistance''', another type of friction or fluid friction) is a [[Physics:Force|force]] acting opposite to the relative motion of any object moving with respect to a surrounding fluid.<ref>{{cite web|url=http://www.merriam-webster.com/dictionary/drag|title=Definition of DRAG|website=www.merriam-webster.com}}</ref> This can exist between two fluid layers (or surfaces) or a fluid and a [[Physics:Solid|solid]] surface. Unlike other resistive forces, such as dry [[Physics:Friction|friction]], which are nearly independent of velocity, drag forces depend on velocity.<ref>French (1970), p. 211, Eq. 7-20</ref><ref name=NASAdrag>{{cite web|title=What is Drag?|url=http://www.grc.nasa.gov/WWW/k-12/airplane/drag1.html|access-date=2019-02-23|archive-url=https://web.archive.org/web/20100524003905/http://www.grc.nasa.gov/WWW/K-12/airplane/drag1.html|archive-date=2010-05-24|url-status=dead}}</ref>
Drag force is proportional to the velocity for a [[Physics:Laminar flow|laminar flow]] and the squared velocity for a turbulent flow. Even though the ultimate cause of a drag is viscous friction, the turbulent drag is independent of [[Physics:Viscosity|viscosity]].<ref>{{cite book | author=G. Falkovich| year=2011 | title=Fluid Mechanics (A short course for physicists)|url=http://www.cambridge.org/gb/knowledge/isbn/item6173728/?site_locale=en_GB | publisher=Cambridge University Press | isbn=978-1-107-00575-4 }}</ref> Drag forces always decrease fluid velocity relative to the solid object in the fluid's path.}}
{{term|term= '''[[Physics:Drift current|Drift current]]'''}}{{defn|defn=In [[Physics:Condensed matter physics|condensed matter physics]] and [[Chemistry:Electrochemistry|electrochemistry]], '''drift current''' is the [[Physics:Electric current|electric current]], or movement of [[Physics:Charge carrier|charge carrier]]s, which is due to the applied [[Physics:Electric field|electric field]], often stated as the [[Physics:Electromotive force|electromotive force]] over a given distance. When an electric field is applied across a semiconductor material, a current is produced due to the flow of charge carriers.}}
{{term|term= '''[[Physics:Ductility|Ductility]]'''}}{{defn|defn=Is a measure of a material's ability to undergo significant plastic deformation before rupture, which may be expressed as percent elongation or percent area reduction from a tensile test.}}
{{term|term= '''[[Physics:Dynamics (mechanics)|Dynamics]]'''}}{{defn|defn=Is the branch of [[Physics:Classical mechanics|classical mechanics]] concerned with the study of [[Physics:Force|force]]s and their effects on [[Physics:Motion|motion]]. [[Biography:Isaac Newton|Isaac Newton]] defined the fundamental [[Physical law|physical law]]s which govern dynamics in physics, especially his second law of motion.}}
{{term|term= '''[[Physics:Dyne|Dyne]]'''}}{{defn|defn=Is a derived unit of [[Physics:Force|force]] specified in the centimetre–gram–second (CGS) system of units, a predecessor of the modern [[International System of Units|SI]]. }}
{{glossary end}}

==E==
{{glossary}}
{{term|term= '''[[Finance:Economics|Economics]]'''}}{{defn|defn=The scientific study of the production, distribution and consumption of goods.}}
{{term|term= '''[[Physics:Effusion|Effusion]]'''}}{{defn|defn=In physics and chemistry, effusion is the process in which a gas escapes from a container through a hole of diameter considerably smaller than the [[Physics:Mean free path|mean free path]] of the molecules.<ref>K.J. Laidler and J.H. Meiser, Physical Chemistry, Benjamin/Cummings 1982, p.18. {{ISBN|0-8053-5682-7}}</ref>}}
{{term|term= '''[[Physics:Elastic modulus|Elastic modulus]]'''}}{{defn|defn= The amount a material will deform per unit force.}} 
{{term|term= '''[[Physics:Elasticity|Elasticity]]'''}}{{defn|defn=In [[Physics:Physics|physics]], elasticity is the ability of a body to resist a distorting influence and to return to its original size and shape when that influence or force is removed. Solid objects will [[Engineering:Deformation (engineering)|deform]] when adequate [[Structural load|forces]] are applied to them. If the material is elastic, the object will return to its initial shape and size when these forces are removed.}} 
{{term|term= '''[[Physics:Electric charge|Electric charge]]'''}}{{defn|defn=is the [[Physics:Physical property|physical property]] of [[Physics:Matter|matter]] that causes it to experience a [[Physics:Force|force]] when placed in an [[Physics:Electromagnetic field|electromagnetic field]]. There are two types of electric charges; ''positive'' and ''negative'' (commonly carried by [[Physics:Proton|proton]]s and [[Physics:Electron|electron]]s respectively). Like charges repel and unlike attract. An object with an absence of net charge is referred to as ''{{Visible anchor|neutral|neutral}}''. Early knowledge of how charged substances interact is now called [[Physics:Classical electrodynamics|classical electrodynamics]], and is still accurate for problems that do not require consideration of [[Physics:Quantum mechanics|quantum effects]].}} 
{{term|term= '''Electric circuit'''}}{{defn|defn=Is an electrical network consisting of a closed loop, giving a return path for the current.}}
{{term|term= '''[[Physics:Electric current|Electric current]]'''}}{{defn|defn= Is a flow of [[Physics:Electric charge|electric charge]].<ref name="horowitz">{{cite book|title=The art of electronics|last1=Horowitz|first1=Paul|last2=Hill|first2=Winfield|author-link2=Winfield Hill|date=2015|publisher={{wipe|Cambridge University Press}}|isbn=978-0-521-80926-9|edition=3rd}}</ref>{{rp|2}} In electric circuits this charge is often carried by moving [[Physics:Electron|electron]]s in a [[Engineering:Wire|wire]]. It can also be carried by [[Physics:Ion|ion]]s in an [[Physics:Electrolyte#Electrochemistry|electrolyte]], or by both ions and electrons such as in an ionised gas ([[Physics:Plasma|plasma]]).<ref>{{cite book
 | title = The electronics companion
 | author = Anthony C. Fischer-Cripps
 | publisher = CRC Press
 | year = 2004
 | isbn = 978-0-7503-1012-3
 | page = 13
 | url = https://books.google.com/books?id=3SsYctmvZkoC&pg=PA13
 }}</ref>

The [[International System of Units|SI]] unit for measuring an electric current is the [[Ampere|ampere]], which is the flow of electric charge across a surface at the rate of one [[Coulomb|coulomb]] per second. Electric current is measured using a device called an [[Engineering:Ammeter|ammeter]].<ref name="learn-physics-today">{{cite web
 |url = http://library.thinkquest.org/10796/ch13/ch13.htm
 |title = Learn Physics Today!
 |access-date = 2009-03-10
 |author1 = Lakatos, John
 |author2 = Oenoki, Keiji
 |author3 = Judez, Hector
 |author4 = Oenoki, Kazushi
 |author5 = Hyun Kyu Cho
 |date = March 1998
 |publisher = Colegio Dr. Franklin D. Roosevelt
 |location = Lima, Peru
 |url-status = dead
 |archive-url = https://web.archive.org/web/20090227065653/http://library.thinkquest.org/10796/ch13/ch13.htm
 |archive-date = 2009-02-27
}}</ref>}}
{{term|term= '''[[Physics:Electric displacement field|Electric displacement field]]'''}}{{defn|defn=In [[Physics:Physics|physics]], the '''electric displacement field''', denoted by '''D''', is a [[Vector field|vector field]] that appears in [[Physics:Maxwell's equations|Maxwell's equations]]. It accounts for the effects of [[Physics:Charge density#Free, bound and total charge|free and bound charge]] within materials. "'''D'''" stands for "displacement", as in the related concept of [[Physics:Displacement current|displacement current]] in [[Physics:Dielectric|dielectric]]s. In [[Physics:Free space|free space]], the electric displacement field is equivalent to [[Physics:Flux#Electric flux|flux density]], a concept that lends understanding to [[Physics:Gauss's law|Gauss's law]]. In the [[International System of Units]] (SI), it is expressed in units of coulomb per meter squared (C&sdot;m<sup>−2</sup>).}}
{{term|term= '''[[Engineering:Electric generator|Electric generator]]'''}}{{defn|defn=In [[Engineering:Electricity generation|electricity generation]], a '''generator''',also called '''electric generator''', '''electrical generator''', and '''electromagnetic generator'''. is a device that converts motive power ([[Physics:Mechanical energy|mechanical energy]]) into electrical power for use in an external [[Physics:Electrical circuit|circuit]]. Sources of mechanical energy include [[Engineering:Steam turbine|steam turbine]]s, [[Engineering:Gas turbine|gas turbine]]s, water turbines, [[Earth:Internal combustion engine|internal combustion engine]]s and even hand [[Engineering:Crank (mechanism)|crank]]s. }}
{{term|term= '''[[Physics:Electric field|Electric field]]'''}}{{defn|defn=Surrounds an [[Physics:Electric charge|electric charge]], and exerts force on other charges in the field, attracting or repelling them.<ref>{{cite book | last1 = Purcell | first1=Edward M. |last2= Morin | first2=David J.| title=Electricity and Magnetism | edition= 3rd | publisher= Cambridge University Press |  location = New York| year = 2013 | pages=14–20| isbn= 978-1-107-01402-2}}</ref><ref>Browne, p 225: "... around every charge there is an aura that fills all space. This aura is the electric field due to the charge. The electric field is a vector field... and has a magnitude and direction."</ref> Electric field is sometimes abbreviated as '''E-field'''.}}
{{term|term= '''[[Physics:Electric field gradient|Electric field gradient]]'''}}{{defn|defn=In [[Physics:Atomic physics|atomic]], [[Physics:Molecular physics|molecular]], and [[Physics:Solid-state physics|solid-state physics]], the '''electric field gradient''' ('''EFG''') measures the rate of change of the [[Physics:Electric field|electric field]] at an [[Physics:Atomic nucleus|atomic nucleus]] generated by the [[Physics:Electron|electron]]ic charge distribution and the other nuclei.}}
{{term|term= '''[[Physics:Electric motor|Electric motor]]'''}}{{defn|defn=Is an [[Engineering:Electric machine|electrical machine]] that converts [[Physics:Electrical energy|electrical energy]] into [[Physics:Mechanical energy|mechanical energy]]. Most electric motors operate through the interaction between the motor's [[Physics:Magnetic field|magnetic field]] and [[Physics:Electrical conductor|winding currents]] to generate force in the form of [[Physics:Rotation|rotation]]. Electric motors can be powered by [[Physics:Direct current|direct current]] (DC) sources, such as from batteries, motor vehicles or rectifiers, or by [[Physics:Alternating current|alternating current]] (AC) sources, such as a power grid, inverters or electrical generators. An [[Engineering:Electric generator|electric generator]] is mechanically identical to an electric motor, but operates in the reverse direction, accepting mechanical energy (such as from flowing water) and converting this mechanical energy into electrical energy.}}
{{term|term= '''[[Physics:Electric potential|Electric potential]]'''}}{{defn|defn=(Also called the ''electric field potential'', potential drop or the '''electrostatic potential''') is the amount of [[Physics:Work|work]] needed to move a unit  of [[Physics:Electric charge|positive charge]] from a reference point to a specific point inside the field without producing an acceleration. Typically, the reference point is the Earth or a point at [[Infinity|infinity]], although any point beyond the influence of the electric field charge can be used.}}
{{term|term= '''Electrical potential energy'''}}{{defn|defn=Electric potential energy, or electrostatic potential energy, is a [[Physics:Potential energy|potential energy]] (measured in [[Joule|joule]]s) that results from [[Physics:Conservative force|conservative]] [[Physics:Coulomb force|Coulomb force]]s and is associated with the configuration of a particular set of point [[Physics:Electric charge|charges]] within a defined [[Physics:Physical system|system]]. An ''object'' may have electric potential energy by virtue of two key elements: its own electric charge and its relative position to other electrically charged ''objects''. The term "electric potential energy" is used to describe the potential energy in systems with [[Time-variant system|time-variant]] [[Physics:Electric field|electric field]]s, while the term "electrostatic potential energy" is used to describe the potential energy in systems with [[Time-invariant system|time-invariant]] electric fields.}}
{{term|term= '''[[Physics:Electric power|Electric power]]'''}}{{defn|defn=Is the rate, per unit time, at which [[Physics:Electrical energy|electrical energy]] is transferred by an electric circuit. The SI unit of [[Physics:Power|power]] is the [[Watt|watt]], one [[Joule|joule]] per [[Second|second]].}}
{{term|term= '''[[Electrical engineering]]'''}}{{defn|defn=Is a technical discipline concerned with the study, design and application of equipment, devices and systems which use [[Physics:Electricity|electricity]], [[Engineering:Electronics|electronics]], and [[Physics:Electromagnetism|electromagnetism]]. It emerged as an identified activity in the latter half of the 19th century after [[Finance:Commercialization|commercialization]] of the electric telegraph, the [[Engineering:Telephone|telephone]], and electrical power generation, distribution and use. .}}
{{term|term= '''[[Physics:Electrical resistance and conductance|Electrical conductance]]'''}}{{defn|defn=The electrical resistance of an object is a measure of its opposition to the flow of electric current. The inverse quantity is {{vanchor|electrical conductance|CONDUCTANCE}}, and is the ease with which an electric current passes. Electrical resistance shares some conceptual parallels with the notion of mechanical [[Physics:Friction|friction]]. The [[International System of Units|SI]] unit of electrical resistance is the [[Ohm|ohm]] (Ω), while electrical conductance is measured in [[Siemens (unit)|siemens]] (S).}}
{{term|term= '''[[Physics:Electrical conductor|Electrical conductor]]'''}}{{defn|defn=Is an object or type of material that allows the flow of charge (electrical current) in one or more directions. Materials made of metal are common electrical conductors. Electrical current is generated by the flow of negatively charged electrons, positively charged holes, and positive or negative ions in some cases.}}
{{term|term= '''[[Physics:Electrical impedance|Electrical impedance]]'''}}{{defn|defn=Is the measure of the opposition that a [[Physics:Electrical circuit|circuit]] presents to a [[Physics:Electric current|current]] when a [[Physics:Voltage|voltage]] is applied. The term ''complex impedance'' may be used interchangeably.}}
{{term|term= '''Electrical insulator'''}}{{defn|defn=Is a material whose internal [[Physics:Electric charge|electric charge]]s do not flow freely; very little [[Physics:Electric current|electric current]] will flow through it under the influence of an [[Physics:Electric field|electric field]]. This contrasts with other materials, [[Physics:Semiconductor|semiconductor]]s and [[Physics:Electrical conductor|conductors]], which conduct electric current more easily. The property that distinguishes an insulator is its resistivity; insulators have higher resistivity than semiconductors or conductors.}}
{{term|term= '''[[Physics:Electrical network|Electrical network]]'''}}{{defn|defn=Is an interconnection of [[Engineering:Electronic component|electrical component]]s (e.g., [[Physics:Battery (electricity)|batteries]], [[Engineering:Resistor|resistor]]s, [[Engineering:Inductor|inductor]]s, [[Engineering:Capacitor|capacitor]]s, [[Engineering:Switch|switch]]es, [[Engineering:Transistor|transistor]]s) or a model of such an interconnection, consisting of [[Engineering:Electrical element|electrical element]]s (e.g., [[Engineering:Voltage source|voltage source]]s, [[Physics:Current source|current source]]s, [[Physics:Electrical resistance and conductance|resistance]]s, [[Physics:Inductance|inductance]]s, [[Physics:Capacitance|capacitance]]s). An electrical circuit is a network consisting of a closed loop, giving a return path for the current. [[Engineering:Linear circuit|Linear]] electrical networks, a special type consisting only of sources (voltage or current), linear lumped elements (resistors, capacitors, inductors), and linear distributed elements (transmission lines), have the property that signals are [[Superposition principle|linearly superimposable]]. They are thus more easily analyzed, using powerful [[Frequency domain|frequency domain]] methods such as [[Laplace transform]]s, to determine [[Physics:Direct current|DC response]], [[Physics:Alternating current|AC response]], and [[Transient response|transient response]].}}
{{term|term= '''[[Physics:Electrical resistance and conductance|Electrical resistance]]'''}}{{defn|defn=The electrical resistance of an object is a measure of its opposition to the flow of electric current. The inverse quantity is {{vanchor|electrical conductance|CONDUCTANCE}}, and is the ease with which an electric current passes. Electrical resistance shares some conceptual parallels with the notion of mechanical [[Physics:Friction|friction]]. The [[International System of Units|SI]] unit of electrical resistance is the [[Ohm|ohm]] (Ω), while electrical conductance is measured in [[Siemens (unit)|siemens]] (S).}}
{{term|term= '''[[Physics:Electricity|Electricity]]'''}}{{defn|defn=Is the set of [[Physics:Physics|physical]] [[Philosophy:Phenomenon|phenomena]] associated with the presence and [[Physics:Motion|motion]] of [[Physics:Matter|matter]] that has a property of [[Physics:Electric charge|electric charge]]. Electricity is related to [[Physics:Magnetism|magnetism]], both being part of the phenomenon of [[Physics:Electromagnetism|electromagnetism]], as described by [[Physics:Maxwell's equations|Maxwell's equations]]. Various common phenomena are related to electricity, including [[Astronomy:Lightning|lightning]], [[Physics:Static electricity|static electricity]], electric heating, [[Physics:Electric discharge|electric discharge]]s and many others.}}
{{term|term= '''[[Physics:Electrodynamics|Electrodynamics]]'''}}{{defn|defn=In physics, the phenomena associated with moving [[Physics:Electric charge|electric charge]]s, and their [[Interaction|interaction]] with electric and [[Physics:Magnetic|magnetic]] fields; the study of these phenomena.<ref>[https://en.wiktionary.org/wiki/electrodynamics Wiktionary]</ref>}}
{{term|term= '''[[Physics:Electromagnet|Electromagnet]]'''}}{{defn|defn=Is a type of [[Physics:Magnet|magnet]] in which the [[Physics:Magnetic field|magnetic field]] is produced by an [[Physics:Electric current|electric current]]. Electromagnets usually consist of wire wound into a [[Engineering:Electromagnetic coil|coil]]. A current through the wire creates a magnetic field which is concentrated in the hole, denoting the centre of the coil. The magnetic field disappears when the current is turned off. The wire turns are often wound around a [[Physics:Magnetic core|magnetic core]] made from a [[Physics:Ferromagnetic|ferromagnetic]] or ferrimagnetic material such as [[Chemistry:Iron|iron]]; the magnetic core concentrates the [[Physics:Magnetic flux|magnetic flux]] and makes a more powerful magnet.}}
{{term|term= '''[[Physics:Electromagnetic field|Electromagnetic field]]'''}}{{defn|defn=An electromagnetic field (also ''EM field'') is a classical (i.e. non-quantum) [[Physics:Field|field]] produced by accelerating [[Physics:Electric charge|electric charge]]s.<ref>{{cite book |author=Richard Feynman |title=The Feynman Lectures on Physics Vol II |publisher=Addison Wesley Longman |year=1970 |isbn=978-0-201-02115-8 |url=http://www.feynmanlectures.caltech.edu/II_01.html#Ch1-S2 |quote=A “field” is any physical quantity which takes on different values at different points in space.}}</ref> It is the field described by [[Physics:Classical electrodynamics|classical electrodynamics]] and is the classical counterpart to the [[Physics:Electromagnetic field tensor|quantized electromagnetic field tensor]] in [[Physics:Quantum electrodynamics|quantum electrodynamics]]. The electromagnetic field propagates at the speed of light (in fact, this field can be identified ''as'' light) and interacts with charges and currents. Its [[Physics:Electromagnetic field tensor|quantum counterpart]] is one of the four fundamental forces of nature (the others are gravitation, [[Physics:Weak interaction|weak interaction]] and [[Physics:Strong interaction|strong interaction]].)}}
{{term|term= '''[[Physics:Electromagnetic radiation|Electromagnetic radiation]]'''}}{{defn|defn=In [[Physics:Physics|physics]], electromagnetic radiation (''EM radiation'' or ''EMR'') refers to the waves (or their [[Physics:Quantum|quanta]], [[Physics:Photon|photon]]s) of the [[Physics:Electromagnetic field|electromagnetic field]], propagating (radiating) through space, carrying electromagnetic [[Physics:Radiant energy|radiant energy]].<ref>*{{cite book | author=Purcell and Morin, Harvard University. | title=Electricity and Magnetism, 820p| edition= 3rd | publisher= Cambridge University Press, New York| year = 2013 | isbn= 978-1-107-01402-2}} p 430: "These waves... require no medium to support their propagation. Traveling electromagnetic waves carry energy, and... the ''Poynting'' vector describes the energy flow...;" p 440: ... the electromagnetic wave must have the following properties: 1) The field pattern travels with speed c (speed of light); 2) At every point within the wave... the electric field strength E equals "c" times the magnetic field strength B; 3) The electric field and the magnetic field are perpendicular to one another and to the direction of travel, or propagation."</ref> It includes [[Radio wave|radio wave]]s, [[Physics:Microwave|microwave]]s, [[Physics:Infrared|infrared]], [[Physics:Light|(visible) light]], [[Physics:Ultraviolet|ultraviolet]], [[Physics:X-ray|X-ray]]s, and [[Physics:Gamma ray|gamma ray]]s.<ref>* {{cite book | author=Browne, Michael | title=Physics for Engineering and Science, p427| edition= 2nd | publisher= McGraw Hill/Schaum, New York.| year = 2013 | isbn= 978-0-07-161399-6}}; p319: "For historical reasons, different portions of the EM spectrum are given different names, although they are all the same kind of thing. Visible light constitutes a narrow range of the spectrum, from wavelengths of about 400-800 nm.... ;p 320 "An electromagnetic wave carries forward momentum... If the radiation is absorbed by a surface, the momentum drops to zero and a force is exerted on the surface... Thus the radiation pressure of an electromagnetic wave is (formula)."</ref>}}
{{term|term= '''[[Physics:Electromechanics|Electromechanics]]'''}}{{defn|defn=Electromechanics<ref>[https://books.google.com/books?id=fbdAAAAAYAAJ Course in Electro-mechanics], for Students in Electrical Engineering, 1st Term of 3d Year, Columbia University, Adapted from Prof. F.E. Nipher's "Electricity and Magnetism". By Fitzhugh Townsend. 1901.</ref><ref>{{cite journal | author1=Szolc T. |author2=Konowrocki R. |author3=Michajłow M. |author4=Pregowska A. |title=An investigation of the dynamic electromechanical coupling effects in machine drive systems driven by asynchronous motors |journal=Mechanical Systems and Signal Processing |volume=49 |issue=1–2 |pages=118–134 | publisher= Mechanical Systems and Signal Processing|date=2014 |doi=10.1016/j.ymssp.2014.04.004|bibcode=2014MSSP...49..118S }}</ref><ref>[https://archive.org/details/elementsofelectr00robi The Elements of Electricity], "Part V. [https://books.google.com/books?id=w47OAAAAMAAJ/page/433 Electro-Mechanics]." By Wirt Robinson. John Wiley & sons, Incorporated, 1922.</ref><ref>{{cite journal | author1=Konowrocki R. |author2=Szolc T. |author3=Pochanke A. |author4=Pregowska A. |title=An influence of the stepping motor control and friction models on precise positioning of the complex mechanical system| publisher= Mechanical Systems and Signal Processing, Vol.70-71, pp.397-413 |issn=0888-3270 |date=2016 |doi=10.1016/j.ymssp.2015.09.030 |volume=70-71 |journal=Mechanical Systems and Signal Processing |pages=397–413|bibcode=2016MSSP...70..397K }}</ref> combines processes and procedures drawn from [[Electrical engineering|electrical engineering]] and [[Engineering:Mechanical engineering|mechanical engineering]]. Electromechanics focuses on the interaction of electrical and mechanical systems as a whole and how the two systems interact with each other. This process is especially prominent in systems such as those of DC or AC rotating electrical machines which can be designed and operated to generate power from a mechanical process ([[Engineering:Electric generator|generator]]) or used to power a mechanical effect ([[Physics:Electric motor|motor]]). Electrical engineering in this context also encompasses [[Electronic engineering|electronics engineering]].}}
{{term|term= '''[[Physics:Electron|Electron]]'''}}{{defn|defn=Is a [[Physics:Subatomic particle|subatomic particle]], symbol {{SubatomicParticle|Electron}} or {{SubatomicParticle|beta-}}, whose [[Physics:Electric charge|electric charge]] is negative one [[Physics:Elementary charge|elementary charge]].<ref>{{cite web |last=Coff |first=Jerry |title=What Is An Electron |url=http://www.universetoday.com/73323/what-is-an-electron/ |access-date=10 September 2010 |date=2010-09-10 |df=dmy-all}}</ref> Electrons belong to the first [[Physics:Generation (particle physics)|generation]] of the [[Physics:Lepton|lepton]] particle family,<ref name="curtis74">
{{cite book
 | last = Curtis | first = L.J.
 | year = 2003
 | title = Atomic Structure and Lifetimes: A Conceptual Approach
 | url = https://books.google.com/books?id=KmwCsuvxClAC&pg=PA74
 | page = 74
 | publisher = Cambridge University Press
 | isbn = 978-0-521-53635-6
}}</ref> and are generally thought to be [[Physics:Elementary particle|elementary particle]]s because they have no known components or substructure.<ref>{{cite journal | last=Eichten | first=Estia J. | last2=Lane | first2=Kenneth D. | last3=Peskin | first3=Michael E. | title=New Tests for Quark and Lepton Substructure | journal=Physical Review Letters | publisher=American Physical Society (APS) | volume=50 | issue=11 | date=1983-03-14 | issn=0031-9007 | doi=10.1103/physrevlett.50.811 | pages=811–814|bibcode=1983PhRvL..50..811E}} OSTI 1446807.</ref> The electron has a [[Physics:Invariant mass|mass]] that is approximately [[Proton-to-electron mass ratio|1/1836]] that of the [[Physics:Proton|proton]].<ref>[https://physics.nist.gov/cgi-bin/cuu/Value?mpsme "CODATA value: proton-electron mass ratio". 2006 CODATA recommended values. National Institute of Standards and Technology. Retrieved 18 July 2009.]</ref> [[Physics:Quantum mechanics|Quantum mechanical]] properties of the electron include an intrinsic [[Physics:Angular momentum|angular momentum]] ([[Physics:Spin|spin]]) of a half-integer value, expressed in units of the [[Physics:Reduced Planck constant|reduced Planck constant]], ''ħ''. Being [[Physics:Fermion|fermion]]s, no two electrons can occupy the same [[Physics:Quantum state|quantum state]], in accordance with the [[Physics:Pauli exclusion principle|Pauli exclusion principle]].<ref name="curtis74"/> Like all elementary particles, electrons exhibit properties of both particles and waves: they can collide with other particles and can be [[Physics:Electron diffraction|diffracted]] like light. The wave properties of electrons are easier to observe with experiments than those of other particles like [[Physics:Neutron|neutron]]s and protons because electrons have a lower mass and hence a longer de Broglie wavelength for a given energy.}}
{{term|term= '''[[Physics:Electronvolt|Electronvolt]]'''}}{{defn|defn=In [[Physics:Physics|physics]], an electronvolt (symbol eV, also written ''electron-volt'' and ''electron volt'') is the amount of [[Physics:Kinetic energy|kinetic energy]] gained by a single [[Physics:Electron|electron]] accelerating from rest through an [[Physics:Voltage|electric potential difference]] of one [[Volt|volt]] in vacuum. When used as a [[Units of energy|unit of energy]], the numerical value of 1 eV in [[Joule|joule]]s (symbol J) is equivalent to the numerical value of the charge of an electron in [[Coulomb|coulomb]]s (symbol C). Under the [[2019 redefinition of the SI base units|2019 redefinition of the SI base units]], this sets 1 eV equal to the exact value {{val|1.602176634|e=-19}} J.<ref>"CODATA Value: Planck constant in eV s".https://physics.nist.gov/cgi-bin/cuu/Value?hev Archived https://web.archive.org/web/20150122120538/http://physics.nist.gov/cgi-bin/cuu/Value?hev from the original on 22 January 2015. Retrieved 30 March 2015.</ref> }}
{{term|term= '''[[Physics:Electron pair|Electron pair]]'''}}{{defn|defn=In [[Chemistry:Chemistry|chemistry]], an electron pair, or ''Lewis pair'', consists of two [[Physics:Electron|electron]]s that occupy the same [[Chemistry:Molecular orbital|molecular orbital]] but have opposite [[Physics:Spin|spins]]. [[Biography:Gilbert N. Lewis|Gilbert N. Lewis]] introduced the concepts of both the electron pair and the covalent bond in a landmark paper he published in 1916.<ref>{{cite book|author=Jean Maruani|title=Molecules in Physics, Chemistry and Biology: v. 3: Electronic Structure and Chemical Reactivity|url=https://books.google.com/books?id=euM5z6aN6_0C&pg=PA73|access-date=14 March 2013|year=1989|publisher=Springer|isbn=978-90-277-2598-1|page=73}}</ref>
}}
{{term|term= '''[[Chemistry:Electronegativity|Electronegativity]]'''}}{{defn|defn=Symbolized as <span class="nounderlines">''χ''</span>, is the measurement of the tendency of an [[Physics:Atom|atom]] to attract a shared pair of [[Physics:Electron|electron]]s (or [[Physics:Electron density|electron density]]).<ref name="definition">{{GoldBookRef|file=E01990|title=Electronegativity}}</ref> An atom's electronegativity is affected by both its [[Physics:Atomic number|atomic number]] and the distance at which its valence electrons reside from the charged nucleus. The higher the associated electronegativity, the more an atom or a substituent group attracts electrons.}}
{{term|term= '''[[Engineering:Electronics|Electronics]]'''}}{{defn|defn=Comprises the physics, engineering, technology and applications that deal with the emission, flow and control of [[Physics:Electron|electron]]s in [[Physics:Vacuum|vacuum]] and [[Physics:Matter|matter]].<ref>{{Cite encyclopedia|url=https://www.britannica.com/technology/electronics|title=electronics {{!}} Devices, Facts, & History|encyclopedia=Encyclopedia Britannica|access-date=2018-09-19}}</ref> It uses active devices to control electron flow by [[Engineering:Amplifier|amplification]] and [[Engineering:Rectifier|rectification]], which distinguishes it from  classical [[Electrical engineering|electrical engineering]] which uses passive effects such as [[Physics:Electrical resistance and conductance|resistance]], [[Physics:Capacitance|capacitance]] and [[Physics:Inductance|inductance]] to control [[Physics:Electric current|current]] flow.}}
{{term|term= '''[[Physics:Endothermic process|Endothermic process]]'''}}{{defn|defn=Is any process with an increase in the [[Physics:Enthalpy|enthalpy]] ''H'' (or [[Physics:Internal energy|internal energy]] ''U'') of the system.<ref name="Oxtoby8th">Oxtoby, D. W; Gillis, H.P., Butler, L. J. (2015).''Principles of Modern Chemistry'', Brooks Cole. p. 617. {{ISBN|978-1305079113}}</ref> In such a process, a closed system usually absorbs [[Physics:Thermal energy|thermal energy]] from its surroundings, which is [[Physics:Heat|heat]] transfer into the system. It may be a chemical process, such as dissolving ammonium nitrate in water, or a physical process, such as the melting of ice cubes.}}
{{term|term= '''[[Physics:Energy|Energy]]'''}}{{defn|defn=In [[Physics:Physics|physics]], energy is the [[Physics:Physical quantity|quantitative]] [[Physics:Physical property|property]] that must be transferred to an [[Philosophy:Physical body|object]] in order to perform [[Physics:Work (thermodynamics)|work]] on, or to [[Physics:Heat|heat]], the object.<ref group=note>The [[Physics:Second law of thermodynamics|second law of thermodynamics]] imposes limitations on the capacity of a system to transfer energy by performing work, since some of the system's energy might necessarily be {{em|[[Astronomy:Waste heat|consumed]]}} in the form of [[Physics:Heat|heat]] instead. See e.g. {{cite journal |last1=Lehrman |first1=Robert L. |title=Energy Is Not The Ability To Do Work |journal=The Physics Teacher |volume=11 |issue=1 |year=1973 |pages=15–18 |issn=0031-921X |doi=10.1119/1.2349846|bibcode=1973PhTea..11...15L }}</ref> Energy is a [[Conservation law|conserved quantity]]; the law of [[Physics:Conservation of energy|conservation of energy]] states that energy can be [[Physics:Energy transformation|converted]] in form, but not created or destroyed. The [[International System of Units|SI unit]] of energy is the [[Joule|joule]], which is the energy transferred to an object by the [[Physics:Work|work]] of moving it a distance of 1 [[Metre|metre]] against a [[Physics:Force|force]] of 1 [[Newton (unit)|newton]].}}
{{term|term= '''[[Engineering:Engine|Engine]]'''}}{{defn|defn=An engine or ''motor'' is a machine designed to convert one form of [[Physics:Energy|energy]] into [[Physics:Motion|mechanical energy]].<ref>{{cite web|url=http://dictionary.reference.com/browse/motor |title=Motor |quote=a person or thing that imparts motion, esp. a contrivance, as a steam engine, that receives and modifies energy from some source in order to utilize it in driving machinery. |publisher=Dictionary.reference.com |access-date=2011-05-09}}</ref><ref>[http://dictionary.reference.com/browse/motor Dictionary.com: (World heritage)] "3. any device that converts another form of energy into mechanical energy so as to produce motion"</ref> [[Physics:Heat engine|Heat engine]]s convert [[Physics:Heat|heat]] into work via various thermodynamic processes. The [[Earth:Internal combustion engine|internal combustion engine]] is perhaps the most common example of a heat engine, in which heat from the [[Physics:Combustion|combustion]] of a fuel causes rapid pressurisation of the gaseous combustion products in the combustion chamber, causing them to expand and drive a [[Engineering:Piston|piston]], which turns a [[Engineering:Crankshaft|crankshaft]]. [[Physics:Electric motor|Electric motor]]s convert electrical energy into mechanical motion, [[Physics:Pneumatic motor|pneumatic motor]]s use [[Physics:Compressed air|compressed air]], and clockwork motors in wind-up toys use [[Physics:Elastic energy|elastic energy]]. In biological systems, [[Physics:Molecular motor|molecular motor]]s, like [[Biology:Myosin|myosin]]s in [[Biology:Muscle|muscle]]s, use [[Chemistry:Chemical energy|chemical energy]] to create forces and ultimately motion.}}
{{term|term= '''[[Engineering:Engineering|Engineering]]'''}}{{defn|defn=Is the use of [[Scientific method|scientific principles]] to design and build machines, structures, and other items, including bridges, tunnels, roads, vehicles, and buildings.<ref>definition of "engineering" from the
https://dictionary.cambridge.org/dictionary/english/
 Cambridge Academic Content Dictionary © Cambridge University</ref> The discipline of engineering encompasses a broad range of more specialized [[Engineering:List of engineering branches|fields of engineering]], each with a more specific emphasis on particular areas of [[Applied mathematics|applied mathematics]], [[Applied science|applied science]], and types of application. The term ''engineering'' is derived from the [[Social:Latin|Latin]] ''ingenium'', meaning "cleverness" and  ''ingeniare'', meaning "to contrive, devise".<ref>{{cite web|title=About IAENG|url=http://www.iaeng.org/about_IAENG.html|website=iaeng.org|publisher=International Association of Engineers|access-date=December 17, 2016}}</ref>}}
{{term|term= '''[[Finance:Engineering economics|Engineering economics]]'''}}{{defn|defn=Engineering economics, previously known as ''engineering economy'', is a subset of [[Finance:Economics|economics]] concerned with the use and "...application of economic principles"<ref name="Dharmaraj2009">Dharmaraj, E.. Engineering Economics. Mumbai, IN: Himalaya Publishing House, 2009. ProQuest ebrary. Web. 9 November 2016.</ref> in the analysis of engineering decisions.<ref name="Morris1960">Morris, W. Thomas. (1960). Engineering economy: the analysis of management decisions. Homewood, Ill.: R. D. Irwin.</ref> As a discipline, it is focused on the branch of economics known as [[Finance:Microeconomics|microeconomics]] in that it studies the behavior of individuals and firms in making decisions regarding the allocation of limited resources. Thus, it focuses on the decision making process, its context and environment.<ref name="Dharmaraj2009" /> It is pragmatic by nature, integrating economic theory with engineering practice.<ref name="Dharmaraj2009" /> But, it is also a simplified application of microeconomic theory in that it assumes elements such as price determination, competition and demand/supply to be fixed inputs from other sources.<ref name="Dharmaraj2009" /> As a discipline though, it is closely related to others such as [[Statistics|statistics]], [[Mathematics|mathematics]] and [[Social:Cost accounting|cost accounting]].<ref name="Dharmaraj2009" /> It draws upon the logical framework of economics but adds to that the analytical power of mathematics and statistics.<ref name="Dharmaraj2009" />}}
{{term|term= '''Engineering ethics'''}}{{defn|defn=Is the field of system of moral principles that apply to the practice of [[Engineering:Engineering|engineering]]. The field examines and sets the obligations by [[Engineering:Engineer|engineer]]s to [[Organization:Society|society]], to their clients, and to the profession. As a scholarly discipline, it is closely related to subjects such as the [[Philosophy:Philosophy of science|philosophy of science]], the philosophy of engineering, and the ethics of technology.}}
{{term|term= '''[[Earth:Environmental engineering|Environmental engineering]]'''}}{{defn|defn=Is a job type that is a professional engineering [[Philosophy:Discipline|discipline]] and takes from broad [[Science|scientific]] topics like [[Chemistry:Chemistry|chemistry]], [[Biology:Biology|biology]], [[Earth:Ecology|ecology]], [[Earth:Geology|geology]], [[Physics:Hydraulics|hydraulics]], [[Earth:Hydrology|hydrology]], [[Biology:Microbiology|microbiology]], and mathematics to create solutions that will protect and also improve the health of living organisms and improve the quality of the environment.<ref>{{Cite web|url=http://www.aaees.org/careers/|title=Careers in Environmental Engineering and Environmental Science|website=American Academy of Environmental Engineers & Scientists|access-date=2019-03-23}}</ref><ref>"Bureau of Labor Statistics, U.S. Department of Labor.U.S. Department of Labor, Occupational Outlook Handbook, 2010-11 Edition"</ref> Environmental engineering is a sub-discipline of [[Engineering:Civil engineering|civil engineering]] and [[Chemistry:Chemical engineering|chemical engineering]].}}
{{term|term= '''[[Engineering:Engineering physics|Engineering physics]]'''}}{{defn|defn=Or ''engineering science'', refers to the study of the combined disciplines of [[Physics:Physics|physics]], [[Mathematics|mathematics]], [[Chemistry:Chemistry|chemistry]], [[Biology:Biology|biology]], and [[Engineering:Engineering|engineering]], particularly computer, nuclear, electrical, electronic, aerospace, materials or mechanical engineering. By focusing on the [[Scientific method|scientific method]] as a rigorous basis, it seeks ways to apply, design, and develop new solutions in engineering.<ref>"Major: Engineering Physics". The Princeton Review. 2017. p. 01. Retrieved June 4, 2017.</ref><ref>[https://engineeringphysics.princeton.edu/ "Introduction"] (online). Princeton University. Retrieved June 26, 2011.</ref><ref>Khare, P.; A. Swarup (2009-01-26). Engineering Physics: Fundamentals & Modern Applications (13th ed.). Jones & Bartlett Learning. pp. xiii–Preface. ISBN 978-0-7637-7374-8.</ref><ref>[https://www.google.com/search?tbo=p&tbm=bks&q=Engineering+PhysicsEngineering Physics] (online). Retrieved June 26, 2011.</ref>}}
{{term|term= '''[[Biology:Enzyme|Enzyme]]'''}}{{defn|defn=Enzymes are [[Biology:Protein|protein]]s that act as biological [[Chemistry:Catalyst|catalyst]]s (biocatalysts). Catalysts accelerate chemical reactions. The molecules upon which enzymes may act are called [[Chemistry:Substrate|substrates]], and the enzyme converts the substrates into different molecules known as [[Chemistry:Product|products]]. Almost all [[Biology:Metabolism|metabolic processes]] in the [[Biology:Cell|cell]] need [[Biology:Enzyme catalysis|enzyme catalysis]] in order to occur at rates fast enough to sustain life.<ref name = "Stryer_2002">{{cite book |vauthors=Stryer L, Berg JM, Tymoczko JL | title = Biochemistry | publisher = W.H. Freeman | location = San Francisco | year = 2002 | edition = 5th | isbn = 0-7167-4955-6 | url = https://www.ncbi.nlm.nih.gov/books/NBK21154/}}{{Open access}}</ref>{{rp|8.1}}}}
{{term|term= '''[[Astronomy:Escape velocity|Escape velocity]]'''}}{{defn|defn=The minimum velocity at which an object can escape a gravitation field.}} 
{{term|term= '''[[Estimator]]'''}}{{defn|defn=In [[Statistics|statistics]], an estimator is a rule for calculating an estimate of a given quantity based on [[Sample (statistics)|observed data]]: thus the rule (the estimator), the quantity of interest (the [[Estimand|estimand]]) and its result (the estimate) are distinguished.<ref>{{cite book |last1=Mosteller |first1=F. |last2=Tukey |first2=J. W. |orig-year=1968 |chapter=Data Analysis, including Statistics |title=The Collected Works of John W. Tukey: Philosophy and Principles of Data Analysis 1965–1986 |volume=4 |publisher=CRC Press |year=1987 |isbn=0-534-05101-4 |pages=601–720 [p. 633] |chapter-url=https://books.google.com/books?id=C1guHWTlVVoC&pg=PA633 |via=[[Google Books]] }}</ref> For example, the [[Sample mean|sample mean]] is a commonly used estimator of the population mean. There are point and interval estimators. The point estimators yield single-valued results, although this includes the possibility of single vector-valued results and results that can be expressed as a single function. This is in contrast to an interval estimator, where the result would be a range of plausible values (or vectors or functions).}}
{{term|term= '''[[Physics:Euler–Bernoulli beam theory|Euler–Bernoulli beam theory]]'''}}{{defn|defn=Euler–Bernoulli beam theory (also known as engineer's beam theory or classical beam theory)<ref name=Timoshenko>Timoshenko, S., (1953), ''History of strength of materials'', McGraw-Hill New York</ref> is a simplification of the [[Physics:Linear elasticity|linear theory of elasticity]] which provides a means of calculating the load-carrying and [[Engineering:Deflection (engineering)|deflection]] characteristics of [[Physics:Beam (structure)|beams]]. It covers the case for small deflections of a [[Physics:Beam (structure)|beam]] that are subjected to lateral loads only. It is thus a special case of [[Timoshenko beam theory]]. It was first enunciated circa 1750,<ref name=Truesdell>Truesdell, C., (1960), ''The rational mechanics of flexible or elastic bodies 1638–1788'', Venditioni Exponunt Orell Fussli Turici.</ref> but was not applied on a large scale until the development of the Eiffel Tower and the [[Engineering:Ferris wheel|Ferris wheel]] in the late 19th century. Following these successful demonstrations, it quickly became a cornerstone of engineering and an enabler of the [[Physics:Second Industrial Revolution|Second Industrial Revolution]]. Additional mathematical models have been developed such as [[Physics:Plate theory|plate theory]], but the simplicity of beam theory makes it an important tool in the sciences, especially [[Engineering:Structural engineering|structural]] and [[Engineering:Mechanical engineering|mechanical engineering]].}}
{{term|term= '''[[Physics:Exothermic process|Exothermic process]]'''}}{{defn|defn=In [[Physics:Thermodynamics|thermodynamics]], the term exothermic process (exo- : "outside") describes a process or reaction that releases [[Physics:Energy|energy]] from the system to its surroundings, usually in the form of [[Physics:Heat|heat]], but also in a form of [[Physics:Light|light]] (e.g. a spark, flame, or flash), [[Physics:Electricity|electricity]] (e.g. a battery), or [[Physics:Sound|sound]] (e.g. explosion heard when burning hydrogen). Its etymology stems from the Greek prefix ''έξω'' (exō, which means "outwards") and the Greek word ''θερμικός'' (thermikόs, which means "thermal").<ref>[http://www.greek-language.gr/greekLang/modern_greek/tools/lexica/search.html?lq=%CE%B8%CE%B5%CF%81%CE%BC%CE%B9%CE%BA%CF%8C%CF%82&dq= "Gate for the Greek language" on-line dictionary] {{webarchive|url=https://web.archive.org/web/20171205235500/http://www.greek-language.gr/greekLang/modern_greek/tools/lexica/search.html?lq=%CE%B8%CE%B5%CF%81%CE%BC%CE%B9%CE%BA%CF%8C%CF%82&dq= |date=2017-12-05 }}. greek-language.gr</ref>}}
{{glossary end}}

==F==
{{glossary}}
{{term|term= '''[[Physics:Factor of safety|Factor of safety]]'''}}{{defn|defn=('''FoS'''), also known as (and used interchangeably with) '''safety factor''' ('''SF'''), expresses how much stronger a system is than it needs to be for an intended load.}}
{{term|term= '''Falling bodies'''}}{{defn|defn=.}}
{{term|term= '''[[Farad]]'''}}{{defn|defn=<ref>[https://www.bipm.org/en/publications/si-brochure/ The International System of Units (SI)] (8th ed.). Bureau International des Poids et Mesures (International Committee for Weights and Measures). 2006. p. 144.</ref> The farad (symbol: F) is the [[SI derived unit]] of electrical [[Physics:Capacitance|capacitance]], the ability of a body to store an electrical charge. It is named after the English physicist [[Biography:Michael Faraday|Michael Faraday]].}} 
{{term|term= '''[[Physics:Faraday constant|Faraday constant]]'''}}{{defn|defn=Denoted by the symbol {{math|''F''}} and sometimes stylized as ℱ, is named after [[Biography:Michael Faraday|Michael Faraday]]. In [[Physics:Physics|physics]] and [[Chemistry:Chemistry|chemistry]], this constant represents the magnitude of [[Physics:Electric charge|electric charge]] per [[Mole (unit)|mole]] of [[Physics:Electron|electron]]s.<ref>The term "magnitude" is used in the sense of "[[Absolute value|absolute value]]": The charge of an electron is negative, but ''F'' is always defined to be positive.</ref> It has the value 
:{{physconst|F|unit=no|after=&nbsp;C mol<sup>−1</sup>.}} <!--template produces incorrect unit "mol", hence override-->

This constant has a simple relation to two other physical constants:
:<math>F\,=\,eN_{A}</math>
where
:{{physconst|e|symbol=yes|after=;}}
:{{physconst|NA|symbol=yes|after=.}}
Both of these values have exact defined values, and hence ''F'' has a known exact value. ''N''<sub>A</sub> is the [[Physics:Avogadro constant|Avogadro constant]] (the ratio of the number of particles, ''N'', which is unitless, to the amount of substance, ''n'', in units of moles), and ''e'' is the [[Physics:Elementary charge|elementary charge]] or the magnitude of the charge of an electron. This relation holds because the amount of charge of a mole of electrons is equal to the amount of charge in ''one'' electron multiplied by the number of electrons in a mole.}}
{{term|term= '''[[Fermat's principle]]'''}}{{defn|defn=In [[Physics:Optics|optics]], Fermat's principle, or the ''principle of least time'', named after French mathematician [[Biography:Pierre de Fermat|Pierre de Fermat]], is the principle that the path taken between two points by a ray of light is the path that can be traversed in the least time. This principle is sometimes taken as the definition of a ray of light.<ref>Arthur Schuster, ''An Introduction to the Theory of Optics'', London: Edward Arnold, 1904 [https://archive.org/details/anintroductiont02schugoog/page/n62 <!-- pg=41 quote=fermat's-principle. --> online].</ref> However, this version of the principle is not general; a more modern statement of the principle is that rays of light traverse the path of stationary optical length with respect to variations of the path.<ref>{{Citation
|last = Ghatak
|first = Ajoy
|year = 2009
|title = Optics
|edition = 4th
|isbn = 978-0-07-338048-3
}}
</ref> In other words, a ray of light prefers the path such that there are other paths, arbitrarily nearby on either side, along which the ray would take almost exactly the same time to traverse.}}
{{term|term= '''[[Physics:Fick's laws of diffusion|Fick's laws of diffusion]]'''}}{{defn|defn= Describe [[Physics:Diffusion|diffusion]] and were derived by Adolf Fick in 1855. They can be used to solve for the [[Physics:Mass diffusivity|diffusion coefficient]], {{mvar|D}}. Fick's first law can be used to derive his second law which in turn is identical to the [[Diffusion equation|diffusion equation]].}}
{{term|term= '''[[Finite element method]]'''}}{{defn|defn=(FEM), is the most widely used method for solving problems of engineering and mathematical models. Typical problem areas of interest include the traditional fields of [[Structural analysis|structural analysis]], [[Physics:Heat transfer|heat transfer]], [[Physics:Fluid flow|fluid flow]], mass transport, and electromagnetic potential. 
The FEM is a particular [[Numerical analysis|numerical method]] for solving partial differential equations in two or three space variables (i.e., some [[Boundary value problem|boundary value problem]]s). To solve a problem, the FEM subdivides a large system into smaller, simpler parts that are called finite elements. This is achieved by a particular space [[Discretization|discretization]] in the space dimensions, which is implemented by the construction of a [[Types of mesh|mesh]] of the object: the numerical domain for the solution, which has a finite number of points. 
The finite element method formulation of a boundary value problem finally results in a system of [[Algebraic equation|algebraic equation]]s. The method approximates the unknown function over the domain.<ref>{{cite book
 | title = A first course in the finite element method
 | author = Daryl L. Logan
 | publisher = Cengage Learning
 | year = 2011
 | isbn = 978-0495668251
}}</ref>
The simple equations that model these finite elements are then assembled into a larger system of equations that models the entire problem. The FEM then uses variational methods from the [[Calculus of variations|calculus of variations]] to approximate a solution by minimizing an associated error function.}}
{{term|term= '''FIRST'''}}{{defn|defn=For Inspiration and Recognition of Science and Technology – is an organization founded by inventor Dean Kamen in 1989 to develop ways to inspire students in engineering and technology fields.}} 
{{term|term= '''[[Physics:Nuclear fission|Fission]]'''}}{{defn|defn=In [[Physics:Nuclear physics|nuclear physics]] and [[Chemistry:Nuclear chemistry|nuclear chemistry]], nuclear fission is a [[Physics:Nuclear reaction|nuclear reaction]] or a [[Physics:Radioactive decay|radioactive decay]] process in which the [[Physics:Atomic nucleus|nucleus]] of an [[Physics:Atom|atom]] splits into two or more smaller, lighter [[Physics:Atomic nucleus|nuclei]]. The fission process often produces  [[Physics:Gamma ray|gamma]] [[Physics:Photon|photon]]s, and releases a very large amount of [[Physics:Energy|energy]] even by the energetic standards of [[Physics:Radioactive decay|radioactive decay]].}} 
{{term|term= '''[[Flow velocity]]'''}}{{defn|defn=In [[Physics:Continuum mechanics|continuum mechanics]] the flow velocity in [[Physics:Fluid dynamics|fluid dynamics]], also macroscopic velocity<ref>{{cite book |author1=Duderstadt, James J. |author2=Martin, William R. | title= Transport theory | editor=Wiley-Interscience Publications | location= New York| year= 1979 | isbn=978-0471044925|chapter=Chapter 4:The derivation of continuum description from transport equations|page=218}}</ref><ref>{{cite book | author=Freidberg, Jeffrey P.|title=Plasma Physics and Fusion Energy|edition=1|editor=Cambridge University Press|location=Cambridge|year=2008| isbn=978-0521733175|chapter=Chapter 10:A self-consistent two-fluid model|page=225}}</ref> in [[Physics:Statistical mechanics|statistical mechanics]], or drift velocity in [[Physics:Electromagnetism|electromagnetism]], is a [[Vector field|vector field]] used to mathematically describe the motion of a continuum. The length of the flow velocity vector is the flow speed and is a scalar.
It is also called velocity field; when evaluated along a [[Line (geometry)|line]], it is called a velocity profile (as in, e.g., [[Physics:Law of the wall|law of the wall]]).}}
{{term|term= '''[[Physics:Fluid|Fluid]]'''}}{{defn|defn=In [[Physics:Physics|physics]], a fluid is a substance that continually [[Physics:Deformation (mechanics)|deforms]] (flows) under an applied [[Physics:Shear stress|shear stress]], or external force. Fluids are a [[Physics:Phase (matter)|phase]] of [[Physics:Matter|matter]] and include [[Physics:Liquid|liquid]]s, [[Physics:Gas|gas]]es and [[Physics:Plasma|plasmas]]<!--, and to some extent, [[Physics:Plasticity|plastic solids]]  <<  To some extent? To what extent? Solids should be the opposite of fluids in any regard.-->. They are [[Physics:Matter|substances]] with zero [[Physics:Shear modulus|shear modulus]], or, in simpler terms, substances which cannot resist any [[Physics:Shear force|shear force]] applied to them.}} 
{{term|term= '''[[Physics:Fluid dynamics|Fluid dynamics]]'''}}{{defn|defn=In [[Physics:Physics|physics]] and [[Engineering:Engineering|engineering]], fluid dynamics  is a subdiscipline of [[Physics:Fluid mechanics|fluid mechanics]] that describes the flow of [[Physics:Fluid|fluid]]s—[[Physics:Liquid|liquid]]s and [[Physics:Gas|gas]]es. It has several subdisciplines, including [[Physics:Aerodynamics|aerodynamics]] (the study of air and other gases in motion) and hydrodynamics (the study of liquids in motion).}} 
{{term|term= '''[[Physics:Fluid mechanics|Fluid mechanics]]'''}}{{defn|defn=Is the branch of [[Physics:Physics|physics]] concerned with the mechanics of [[Physics:Fluid|fluid]]s ([[Physics:Liquid|liquid]]s, [[Physics:Gas|gas]]es, and [[Physics:Plasma|plasma]]s) and the [[Physics:Force|force]]s on them.<ref>White, Frank M. (2011). Fluid Mechanics (7th ed.). McGraw-Hill. {{ISBN|978-0-07-352934-9}}.</ref>
It has applications in a wide range of disciplines, including [[Engineering:Mechanical engineering|mechanical]], [[Engineering:Civil engineering|civil]], [[Chemistry:Chemical engineering|chemical]] and [[Medicine:Biomedical engineering|biomedical engineering]], [[Physics:Geophysics|geophysics]], [[Physics:Oceanography|oceanography]], [[Physics:Meteorology|meteorology]], [[Physics:Astrophysics|astrophysics]], and [[Biology:Biology|biology]].}}
{{term|term= '''Fluid statics'''}}{{defn|defn=Fluid statics, or ''hydrostatics'', is the branch of [[Physics:Fluid mechanics|fluid mechanics]] that studies "[[Physics:Fluid|fluid]]s at rest and the pressure in a fluid or exerted by a fluid on an immersed body".<ref name="MW dictionary def">{{cite web |title=Hydrostatics |url=https://www.merriam-webster.com/dictionary/hydrostatics |website=Merriam-Webster |access-date=11 September 2018}}</ref>}}
{{term|term= '''Flywheel'''}}{{defn|defn=Is a mechanical device specifically designed to use the conservation of [[Physics:Angular momentum|angular momentum]] so as to efficiently store [[Rotational energy|rotational energy]]; a form of kinetic energy proportional to the product of its [[Physics:Moment of inertia|moment of inertia]] and the square of its [[Physics:Rotational speed|rotational speed]]. In particular, if we assume the flywheel's moment of inertia to be constant (i.e., a flywheel with fixed mass and [[Second moment of area|second moment of area]] revolving about some fixed axis) then the stored (rotational) energy is directly associated with the square of its rotational speed.}}
{{term|term= '''[[Physics:Focus (optics)|Focus]]'''}}{{defn|defn=In [[Physics:Geometrical optics|geometrical optics]], a focus, also called an ''image point'', is the point where [[Physics:Ray (optics)|light rays]] originating from a point on the object [[Physics:Vergence (optics)|converge]].<ref>{{cite web |title=Standard Microscopy Terminology |work=University of Minnesota Characterization Facility website |url=http://www.charfac.umn.edu/glossary/f.html |archive-url=https://web.archive.org/web/20080302163401/http://www.charfac.umn.edu/glossary/f.html |archive-date=2008-03-02 |access-date=2006-04-21}}</ref> Although the focus is conceptually a point, physically the focus has a spatial extent, called the [[Physics:Circle of confusion|blur circle]]. This non-ideal focusing may be caused by [[Physics:Optical aberration|aberrations]] of the imaging optics. In the absence of significant aberrations, the smallest possible blur circle is the Airy disc, which is caused by [[Physics:Diffraction|diffraction]] from the optical system's [[Astronomy:Aperture|aperture]]. Aberrations tend worsen as the aperture diameter increases, while the Airy circle is smallest for large apertures.}}
{{term|term= '''Foot-pound'''}}{{defn|defn=The foot-pound force (symbol: ft⋅lbf,<ref>IEEE Std 260.1™-2004, IEEE Standard Letter Symbols for Units of Measurement (SI Units, Customary Inch-Pound Units, and Certain Other Units)</ref> ft⋅lb<sub>f</sub>,<ref name="isbn_978-0135018583">{{Citation |last1=Fletcher |first1=Leroy S. |last2=Shoup |first2=Terry E. |year=1978 |title=Introduction to Engineering |publisher=Prentice-Hall |url=https://books.google.com/books?id=tyohAQAAIAAJ |isbn=978-0135018583 |lccn=77024142 |postscript=.}}{{rp|257}}</ref> or ft⋅lb <ref>{{Cite book |last1 = Budynas |first1 = Richard G. |last2 = Nisbett |first2 = J. Keith |date = 2014-01-27|title = Mechanical Engineering Design|url = http://www.mheducation.com/highered/product/shigley-s-mechanical-engineering-design-budynas-nisbett/M0073398209.html|publisher = McGraw Hill Education|isbn = 978-0073529288|language = en|url-access=subscription }}</ref>) is a unit of work or [[Physics:Energy|energy]] in the [[Engineering:English Engineering Units|engineering]] and [[Foot–pound–second system#force|gravitational]] systems in United States customary and [[Imperial units|imperial]] units of measure. It is the energy transferred upon applying a [[Physics:Force|force]] of one pound-force (lbf) through a linear [[Displacement (vector)|displacement]] of one [[Foot (unit)|foot]]. The corresponding SI unit is the [[Joule|joule]].}}
{{term|term= '''[[Engineering:Fracture toughness|Fracture toughness]]'''}}{{defn|defn=In [[Physics:Materials science|materials science]], fracture toughness is the critical [[Engineering:Stress intensity factor|stress intensity factor]] of a sharp crack where propagation of the crack suddenly becomes rapid and unlimited. A component's thickness affects the constraint conditions at the tip of a crack with thin components having [[Engineering:Plane stress|plane stress]] conditions and thick components having plane strain conditions. Plane strain conditions give the lowest fracture toughness value which is a material property. The critical value of stress intensity factor in [[Fracture mechanics|mode I]] loading measured under plane strain conditions is known as the ''plane strain fracture toughness'', denoted <math>K_\text{Ic}</math>.<ref name="suresh04">{{cite book |last1=Suresh |first1=S. |year=2004 |title=Fatigue of Materials |publisher=Cambridge University Press |isbn=978-0-521-57046-6}}</ref> When a test fails to meet the thickness and other test requirements that are in place to ensure plane strain conditions, the fracture toughness value produced is given the designation <math>K_\text{c}</math>. Fracture toughness is a quantitative way of expressing a material's resistance to crack propagation and standard values for a given material are generally available.}}
{{term|term= '''[[Physics:Fraunhofer lines|Fraunhofer lines]]'''}}{{defn|defn=In [[Physics:Physics|physics]] and [[Physics:Optics|optics]], the Fraunhofer lines are a set of [[Physics:Spectral line|spectral absorption lines]] named after the German physicist [[Biography:Joseph von Fraunhofer|Joseph von Fraunhofer]] (1787–1826). The lines were originally observed as dark features (absorption lines) in the optical spectrum of the [[Astronomy:Sun|Sun]].}}
{{term|term= '''[[Physics:Free fall|Free fall]]'''}}{{defn|defn=In [[Physics:Classical mechanics|Newtonian physics]], free fall is any motion of a [[Philosophy:Physical body|body]] where [[Physics:Gravity|gravity]] is the only [[Physics:Force|force]] acting upon it. In the context of [[Physics:General relativity|general relativity]], where gravitation is reduced to a space-time curvature, a body in free fall has no force acting on it.}}
{{term|term= '''[[Physics:Frequency modulation|Frequency modulation]]'''}}{{defn|defn=Frequency modulation (FM) is the encoding of [[Information|information]] in a [[Carrier wave|carrier wave]] by varying the instantaneous frequency of the wave. The technology is used in telecommunications, [[Engineering:Radio broadcasting|radio broadcasting]], [[Signal processing|signal processing]], and [[Run-length limited#FM: .280.2C1.29 RLL|computing]].}}
{{term|term= '''[[Physics:Freezing point|Freezing point]]'''}}{{defn|defn=The ''melting point'' (or, rarely, ''liquefaction point'') of a substance is the [[Physics:Temperature|temperature]] at which it changes [[Physics:State of matter|state]] from [[Physics:Solid|solid]] to [[Physics:Liquid|liquid]]. At the melting point the solid and liquid phase exist in [[Physics:Thermodynamic equilibrium|equilibrium]]. The melting point of a substance depends on [[Physics:Pressure|pressure]] and is usually specified at a [[Standard conditions for temperature and pressure|standard pressure]] such as 1 [[Physics:Atmosphere (unit)|atmosphere]] or 100 [[Pascal (unit)|kPa]].

When considered as the temperature of the reverse change from liquid to solid, it is referred to as the ''freezing point'' or ''crystallization point''. Because of the ability of substances to [[Physics:Supercooling|supercool]], the freezing point can easily appear to be below its actual value. When the "characteristic freezing point" of a substance is determined, in fact the actual methodology is almost always "the principle of observing the disappearance rather than the formation of ice, that is, the melting point.<ref>{{cite journal |last1=Ramsay |first1=J. A. |title=A New Method of Freezing-Point Determination for Small Quantities |journal=Journal of Experimental Biology |date=1 May 1949 |volume=26 |issue=1 |pages=57–64 |doi=10.1242/jeb.26.1.57 |pmid=15406812 |url=http://jeb.biologists.org/cgi/pmidlookup?view=long&pmid=15406812 }}</ref>}}
{{term|term= '''[[Physics:Friction|Friction]]'''}}{{defn|defn=Is the [[Physics:Force|force]] resisting the relative motion of solid surfaces, fluid layers, and material elements [[Physics:Sliding (motion)|sliding]] against each other.<ref>{{MerriamWebsterDictionary|friction}}</ref> There are several types of friction:
*''Dry friction'' is a force that opposes the relative lateral motion of two solid surfaces in contact. Dry friction is subdivided into ''static friction'' ("[[Physics:Stiction|stiction]]") between non-moving surfaces, and ''kinetic friction'' between moving surfaces. With the exception of atomic or molecular friction, dry friction generally arises from the interaction of surface features, known as [[Asperity (materials science)|asperities]] (see Figure 1). 
*''Fluid friction'' describes the friction between layers of a viscous fluid that are moving relative to each other.<ref name="Beer">{{cite book
| last2=Johnston |first2=E. Russel, Jr.
| year = 1996
| title = Vector Mechanics for Engineers
| edition = Sixth
| publisher = McGraw-Hill
| isbn = 978-0-07-297688-5
| page = 397
}}</ref><ref name="Meriam">{{cite book
| last1 = Meriam
| first1 = J. L.
| last2 = Kraige
| first2 = L. G.
| year = 2002
| title = Engineering Mechanics
| edition = fifth
| publisher = John Wiley & Sons
| isbn = 978-0-471-60293-4
| page = [https://archive.org/details/engineeringmech100meri/page/328 328]
| url-access = registration
| url = https://archive.org/details/engineeringmech100meri
}}</ref>

*''Lubricated friction'' is a case of fluid friction where a [[Physics:Lubricant|lubricant]] fluid separates two solid surfaces.<ref name="Ruina">{{cite book
| last1 = Ruina | first1 = Andy
| last2 = Pratap |first2=Rudra 
| year = 2002
| title = Introduction to Statics and Dynamics
| publisher = Oxford University Press
| page = 713
| url = http://ruina.tam.cornell.edu/Book/RuinaPratapNoProblems.pdf }}</ref><ref name="Hibbeler">{{cite book
| last = Hibbeler | first = R. C.
| year = 2007
| title = Engineering Mechanics
| url = https://archive.org/details/studypack00rcsc | url-access = registration | edition = Eleventh
| publisher = Pearson, Prentice Hall
| isbn = 978-0-13-127146-3
| page = 393}}</ref><ref name="Soutas-Little">{{cite book
| last1 = Soutas-Little
| first1 = Robert W.
| last2=Inman |first2=Balint
| year = 2008
| title = Engineering Mechanics
| publisher = Thomson
| isbn = 978-0-495-29610-2
| page = 329}}</ref>

*''Skin friction'' is a component of [[Physics:Drag|drag]], the force resisting the motion of a fluid across the surface of a body.
*''Internal friction'' is the force resisting motion between the elements making up a solid material while it undergoes [[Physics:Deformation (mechanics)|deformation]].<ref name="Meriam"/>}}
{{term|term= '''[[Function (mathematics)|Function]]'''}}{{defn|defn=In mathematics, a function<ref group=note>The words '''map''', '''mapping''', '''transformation''', '''correspondence''', and '''operator''' are often used synonymously. {{harvnb|Halmos|1970|p=30}}.</ref> is a [[Binary relation|binary relation]] between two [[Set (mathematics)|sets]] that associates every element of the first set to exactly one element of the second set. Typical examples are functions from [[Integer|integer]]s to integers, or from the [[Real number|real number]]s to real numbers.}}
{{term|term= '''[[Physics:Fundamental frequency|Fundamental frequency]]'''}}{{defn|defn=The fundamental frequency, often referred to simply as the ''fundamental'', is defined as the lowest [[Physics:Frequency|frequency]] of a periodic [[Waveform|waveform]]. In music, the fundamental is the musical [[Physics:Pitch (music)|pitch]] of a note that is perceived as the lowest partial present. In terms of a superposition of [[Physics:Sine wave|sinusoid]]s, the fundamental frequency is the lowest frequency sinusoidal in the sum of harmonically related frequencies, or the frequency of the difference between adjacent frequencies. In some contexts, the fundamental is usually abbreviated as '''{{var|f}}<sub>0</sub>''', indicating the lowest frequency [[Zero-based numbering|counting from zero]].<ref>{{cite web |url= http://www.phon.ucl.ac.uk/home/johnm/sid/sidf.htm |title=sidfn |publisher=Phon.UCL.ac.uk |access-date=2012-11-27 |archive-url= https://web.archive.org/web/20130106050848/http://www.phon.ucl.ac.uk/home/johnm/sid/sidf.htm |archive-date=2013-01-06 |url-status=dead}}</ref><ref>{{cite web|url= http://www.acoustics.hut.fi/publications/files/theses/lemmetty_mst/chap3.html |last=Lemmetty |first=Sami |title=Phonetics and Theory of Speech Production |publisher=Acoustics.hut.fi |date=1999 |access-date=2012-11-27}}</ref><ref>{{cite web |url= http://fourier.eng.hmc.edu/e101/lectures/Fundamental_Frequency.pdf |title=Fundamental Frequency of Continuous Signals |date=2011 |publisher=Fourier.eng.hmc.edu |access-date=2012-11-27}}</ref> In other contexts, it is more common to abbreviate it as '''{{var|f}}<sub>1</sub>''', the first [[Physics:Harmonic|harmonic]].<ref>{{cite web |url=https://nchsdduncanapphysics.wikispaces.com/file/view/Standing+Waves+in+a+Tube+II.pdf |title=Standing Wave in a Tube II – Finding the Fundamental Frequency |publisher=Nchsdduncanapphysics.wikispaces.com |access-date=2012-11-27 |archive-date=2014-03-13 |archive-url=https://web.archive.org/web/20140313133719/https://nchsdduncanapphysics.wikispaces.com/file/view/Standing+Waves+in+a+Tube+II.pdf |url-status=dead }}</ref><ref>{{cite web |url=http://physics.kennesaw.edu/P11_standwaves3.pdf |title=Physics: Standing Waves |publisher=Physics.Kennesaw.edu |access-date=2012-11-27 |archive-date=2019-12-15 |archive-url=https://web.archive.org/web/20191215062640/https://csm.kennesaw.edu/physics/ |url-status=dead }}</ref><ref>{{cite web |url= http://www.colorado.edu/physics/phys1240/phys1240_fa05/notes/lect24_Tu11_22_4up.pdf |title=Phys 1240: Sound and Music |last=Pollock |first=Steven |publisher=Colorado.edu |date=2005 |access-date=2012-11-27 |archive-url=https://web.archive.org/web/20140515180200/http://www.colorado.edu/physics/phys1240/phys1240_fa05/notes/lect24_Tu11_22_4up.pdf |archive-date=2014-05-15 |url-status=dead}}</ref><ref>{{cite web |url= http://hyperphysics.phy-astr.gsu.edu/hbase/waves/string.html |title=Standing Waves on a String |publisher=Hyperphysics.phy-astr.gsu.edu |access-date=2012-11-27}}</ref><ref>{{cite web |url= http://openlearn.open.ac.uk/mod/oucontent/view.php?id=397877&section=5.13.2 |title=Creating musical sounds |work=OpenLearn |publisher=Open University |access-date=2014-06-04}}</ref> (The second harmonic is then {{var|f}}<sub>2</sub> = 2⋅{{var|f}}<sub>1</sub>, etc. In this context, the zeroth harmonic would be 0&nbsp;[[Hertz|Hz]].)}}
{{term|term= '''[[Physics:Fundamental interaction|Fundamental interaction]]'''}}{{defn|defn=In [[Physics:Physics|physics]], the fundamental interactions, also known as ''fundamental forces'', are the interactions that do not appear to be reducible to more basic interactions. There are four fundamental interactions known to exist:  the [[Physics:Gravity|gravitational]] and [[Physics:Electromagnetism|electromagnetic]] interactions, which produce significant long-range forces whose effects can be seen directly in everyday life, and the [[Physics:Strong interaction|strong]] and [[Physics:Weak interaction|weak interaction]]s, which produce forces at [[Physics:Subatomic scale|minuscule, subatomic distances]] and govern nuclear interactions. Some scientists hypothesize that a [[Physics:Fifth force|fifth force]] might exist, but these hypotheses remain speculative.<ref name="Fackler">{{cite book
 | last1 = Fackler
 | first1 = Orrin 
 | last2 = Tran
 | first2 = J. Thanh Van
 | title = 5th Force Neutrino Physics
 | publisher = Atlantica Séguier Frontières
 | date = 1988
 | url = https://books.google.com/books?id=Ke32COxghksC&q=%22fifth+force%22f&pg=PR7
 | isbn = 978-2863320549
 }}</ref><ref name="Weisstein">{{cite web
 | last = Weisstein
 | first = Eric W. 
 | title = Fifth Force
 | work = World of Science
 | publisher = Wolfram Research
 | date = 2007
 | url = http://scienceworld.wolfram.com/physics/FifthForce.html
 | access-date = September 14, 2017}}</ref><ref name="Franklin">{{cite book
 | last1 = Franklin
 | first1 = Allan
 | last2 = Fischbach
 | first2 = Ephraim
 | title = The Rise and Fall of the Fifth Force: Discovery, Pursuit, and Justification in Modern Physics, 2nd Ed.
 | publisher = Springer
 | date = 2016
 | url = https://books.google.com/books?id=7giyCwAAQBAJ&q=%22fifth+force%22&pg=PA146
 | isbn = 978-3319284125
 }}</ref>}}
{{term|term= '''[[Fundamental theorem of calculus]]'''}}{{defn|defn=Is a [[Theorem|theorem]] that links the concept of [[Derivative|differentiating]] a [[Function (mathematics)|function]] with the concept of [[Integral|integrating]] a function.}}
{{term|term= '''Fundamentals of Engineering Examination (US)'''}}{{defn|defn=The Fundamentals of Engineering (FE) exam, also referred to as the ''Engineer in Training'' (''EIT'') ''exam'', and formerly in some states as the ''Engineering Intern'' (''EI'') ''exam'', is the first of two examinations that [[Engineering:Engineer|engineer]]s must pass in order to be licensed as a Professional Engineer in the {{wipe|United States}}. The second examination is Principles and Practice of Engineering Examination. The FE [[Social:Exam|exam]] is open to anyone with a [[Social:Academic degree|degree]] in engineering or a related field, or currently enrolled in the last year of an ABET-accredited engineering degree program. Some state licensure boards permit students to take it prior to their final year, and numerous states allow those who have never attended an approved program to take the exam if they have a state-determined number of years of work experience in engineering. Some states allow those with ABET-accredited "Engineering Technology" or "ETAC" degrees to take the examination. The state of Michigan has no admission pre-requisites for the FE.<ref>{{cite web|url= http://www.michigan.gov/lara/0,4601,7-154-35299_61343_35414_60647_35472-114639--,00.html|title= Professional Engineers Examination}}</ref> The exam is administered by the National Council of Examiners for Engineering and Surveying (NCEES).}}
{{glossary end}}

==G==
{{glossary}}

{{term|term= '''[[Chemistry:Galvanic cell|Galvanic cell]]'''}}{{defn|defn=A galvanic cell or voltaic cell, named after [[Biography:Luigi Galvani|Luigi Galvani]] or [[Biography:Alessandro Volta|Alessandro Volta]], respectively, is an [[Chemistry:Electrochemical cell|electrochemical cell]] that derives electrical energy from spontaneous [[Chemistry:Redox|redox]] reactions taking place within the cell. It generally consists of two different metals immersed in electrolytes, or of individual half-cells with different metals and their ions in solution connected by a [[Chemistry:Salt bridge|salt bridge]] or separated by a porous membrane. Volta was the inventor of the voltaic pile, the first [[Physics:Battery (electricity)|electrical battery]]. In common usage, the word "battery" has come to include a single galvanic cell, but a battery properly consists of multiple cells.<ref>[http://www.merriam-webster.com/dictionary/battery "battery" (def. 4b)], ''Merriam-Webster Online Dictionary'' (2008). Retrieved 6 August 2008.</ref>}}
{{term|term= '''Gamma rays'''}}{{defn|defn=A gamma ray, or gamma radiation (symbol γ or <math>\gamma</math>), is a penetrating form of [[Physics:Electromagnetic radiation|electromagnetic radiation]] arising from the [[Physics:Radioactive decay|radioactive decay]] of [[Physics:Atomic nucleus|atomic nuclei]]. It consists of the shortest wavelength electromagnetic waves and so imparts the highest [[Physics:Photon energy|photon energy]].}}
{{term|term= '''[[Physics:Gas|Gas]]'''}}{{defn|defn=Is one of the [[Physics:State of matter|four fundamental states of matter]] (the others being [[Physics:Solid|solid]], [[Physics:Liquid|liquid]], and [[Physics:Plasma|plasma]]). A pure gas may be made up of individual atoms (e.g. a [[Chemistry:Noble gas|noble gas]] like [[Chemistry:Neon|neon]]), [[Chemistry:Chemical element|elemental]] molecules made from one type of atom (e.g. [[Chemistry:Oxygen|oxygen]]), or [[Chemistry:Chemical compound|compound]] molecules made from a variety of atoms (e.g. [[Chemistry:Carbon dioxide|carbon dioxide]]). A gas [[Physics:Mixture|mixture]], such as air, contains a variety of pure gases. What distinguishes a gas from liquids and solids is the vast separation of the individual gas particles.}}
{{term|term= '''[[Physics:Pressure measurement#Absolute, gauge and differential pressures — zero reference|Gauge pressure]]'''}}{{defn|defn=Is zero-referenced against ambient air pressure, so it is equal to absolute pressure minus atmospheric pressure.}}
{{term|term= '''[[Organization:Geiger counter|Geiger counter]]'''}}{{defn|defn=Is an instrument used for detecting and measuring [[Physics:Ionizing radiation|ionizing radiation]]. Also known as a ''Geiger–Muller counter'' (or ''Geiger–Müller counter''), it is widely used in applications such as radiation [[Physics:Dosimetry|dosimetry]], radiological protection, [[Physics:Experimental physics|experimental physics]], and the nuclear industry.}} 
{{term|term= '''[[Physics:General relativity|General relativity]]'''}}{{defn|defn=General relativity, also known as the ''general theory of relativity'', is the [[Differential geometry|geometric]] [[Scientific theory|theory]] of gravitation published by [[Biography:Albert Einstein|Albert Einstein]] in 1915 and is the current description of gravitation in [[Physics:Modern physics|modern physics]]. General [[Physics:Theory of relativity|relativity]] generalizes [[Physics:Special relativity|special relativity]] and refines [[Physics:Newton's law of universal gravitation|Newton's law of universal gravitation]], providing a unified description of gravity as a geometric property of [[Space|space]] and [[Physics:Time in physics|time]] or four-dimensional [[Physics:Spacetime|spacetime]]. In particular, the ''{{vanchor|[[Curvature|curvature]] of spacetime|Spacetime curvature|curvature of spacetime}}'' is directly related to the [[Physics:Energy|energy]] and [[Physics:Momentum|momentum]] of whatever [[Physics:Matter|matter]] and [[Physics:Radiation|radiation]] are present. The relation is specified by the [[Physics:Einstein field equations|Einstein field equations]], a system of [[Partial differential equation|partial differential equation]]s.}}
{{term|term= '''[[Geometric mean]]'''}}{{defn|defn=In mathematics, the geometric mean is a [[Mean|mean]] or [[Average|average]], which indicates the [[Central tendency|central tendency]] or typical value of a set of numbers by using the product of their values (as opposed to the [[Arithmetic mean|arithmetic mean]] which uses their sum). The geometric mean is defined as the [[Nth root|{{math|''n''}}th root]] of the [[Product (mathematics)|product]] of {{mvar|n}} numbers, i.e., for a set of numbers {{math|''x''<sub>1</sub>, ''x''<sub>2</sub>, ..., ''x<sub>n</sub>''}}, the geometric mean is defined as

:<math>\left(\prod_{i=1}^n x_i\right)^\frac{1}{n} = \sqrt[n]{x_1 x_2 \cdots x_n}</math>}}
{{term|term= '''[[Geometry]]'''}}{{defn|defn=Is, with [[Arithmetic|arithmetic]], one of the oldest branches of [[Mathematics|mathematics]]. It is concerned with properties of space that are related with distance, shape, size, and relative position of figures.<!--Please, do not link this everyday word--><ref name="Risi2015">{{cite book|author=Vincenzo De Risi|title=Mathematizing Space: The Objects of Geometry from Antiquity to the Early Modern Age|url=https://books.google.com/books?id=1m11BgAAQBAJ&pg=PA1|date=31 January 2015|publisher=Birkhäuser|isbn=978-3-319-12102-4|pages=1–}}</ref> A mathematician who works in the field of geometry is called a [[Biography:List of geometers|geometer]].}}
{{term|term= '''[[Physics:Geophysics|Geophysics]]'''}}{{defn|defn=Is a subject of [[Natural science|natural science]] concerned with the physical processes and [[Physics:Physical property|physical properties]] of the [[Astronomy:Earth|Earth]] and its surrounding space environment, and the use of quantitative methods for their analysis. The term ''geophysics'' sometimes refers only to geological applications: Earth's [[Earth:Figure of the Earth|shape]]; its gravitational and [[Earth:Earth's magnetic field|magnetic fields]]; its [[Earth:Structure of the Earth|internal structure]] and [[Astronomy:Earth#Composition|composition]]; its [[Earth:Geodynamics|dynamics]] and their surface expression in [[Earth:Plate tectonics|plate tectonics]], the generation of [[Biology:Magma|magma]]s, volcanism and rock formation.<ref name=Sheriff1991>{{harvnb|Sheriff|1991}}</ref> However, modern geophysics organizations and pure scientists use a broader definition that includes the [[Physics:Water cycle|water cycle]] including snow and ice; [[Physics:Geophysical fluid dynamics|fluid dynamics]] of the oceans and the [[Astronomy:Atmosphere|atmosphere]]; [[Physics:Atmospheric electricity|electricity]] and [[Physics:Magnetism|magnetism]] in the [[Astronomy:Ionosphere|ionosphere]] and [[Astronomy:Magnetosphere|magnetosphere]] and solar-terrestrial relations; and analogous problems associated with the [[Astronomy:Moon|Moon]] and other planets.<ref name=Sheriff1991/><ref name=IUGG>{{harvnb|IUGG|2011}}</ref><ref name=AGUscience>{{harvnb|AGU|2011}}</ref><ref name="Gutenberg (1929)">Gutenberg, B., 1929, Lehrbuch der Geophysik. Leipzig. Berlin (Gebruder Borntraeger).</ref><ref name="Runcorn">Runcorn, S.K, (editor-in-chief), 1967, International dictionary of geophysics:. Pergamon, Oxford, 2 volumes, 1,728 pp., 730 fig</ref>}}
{{term|term= '''[[Engineering:Geotechnical engineering|Geotechnical engineering]]'''}}{{defn|defn=Also known as ''geotechnics'', is the branch of [[Engineering:Civil engineering|civil engineering]] concerned with the engineering behavior of [[Earth:Earth materials|earth materials]]. It uses the principles and methods of soil mechanics and [[Earth:Rock mechanics|rock mechanics]] for the solution of [[Engineering:Engineering|engineering]] problems and the design of engineering works. It also relies on knowledge of [[Earth:Geology|geology]], [[Earth:Hydrology|hydrology]], [[Physics:Geophysics|geophysics]], and other related sciences.}}
{{term|term= '''[[Physics:Gluon|Gluon]]'''}}{{defn|defn=Is an [[Physics:Elementary particle|elementary particle]] that acts as the exchange particle (or [[Physics:Gauge boson|gauge boson]]) for the [[Physics:Strong interaction|strong force]] between [[Physics:Quark|quark]]s. It is analogous to the exchange of [[Physics:Photon|photon]]s in the [[Physics:Electromagnetic force|electromagnetic force]] between two [[Physics:Charged particle|charged particle]]s.<ref name=HyperPhysics>{{cite web
 |author=C.R. Nave
 |title=The Color Force
 |url=http://hyperphysics.phy-astr.gsu.edu/hbase/forces/color.html
 |work=HyperPhysics
 |publisher=[[Organization:Georgia State University|Georgia State University]], Department of Physics
 |access-date=2012-04-02
}}</ref> In layman's terms, they "glue" quarks together, forming [[Physics:Hadron|hadron]]s such as [[Physics:Proton|proton]]s and [[Physics:Neutron|neutron]]s.

In technical terms, gluons are [[Physics:Vector boson|vector]] [[Physics:Gauge boson|gauge boson]]s that mediate [[Physics:Strong interaction|strong interaction]]s of [[Physics:Quark|quark]]s in [[Physics:Quantum chromodynamics|quantum chromodynamics]] (QCD). Gluons themselves carry the [[Physics:Color charge|color charge]] of the strong interaction. This is unlike the [[Physics:Photon|photon]], which mediates the [[Physics:Electromagnetic force|electromagnetic interaction]] but lacks an electric charge. Gluons therefore participate in the strong interaction in addition to mediating it, making QCD significantly harder to analyze than [[Physics:Quantum electrodynamics|quantum electrodynamics]] (QED).}}
{{term|term= '''[[Physics:Graham's law|Graham's law]]'''}}{{defn|defn=''Graham's law of effusion'' (also called ''Graham's law of [[Physics:Diffusion|diffusion]]'') was formulated by Scottish physical chemist Thomas Graham in 1848.<ref name="LM">Keith J. Laidler and John M. Meiser, ''Physical Chemistry'' (Benjamin/Cummings 1982), pp.&nbsp;18–19</ref> Graham found experimentally that the rate of [[Physics:Effusion|effusion]] of a gas is inversely proportional to the square root of the mass of its particles.<ref name="LM"/> This formula can be written as:
:<math>{\mbox{Rate}_1 \over \mbox{Rate}_2}=\sqrt{M_2 \over M_1}</math>,
where:
:Rate<sub>1</sub> is the rate of effusion for the first gas. (volume or number of moles per unit time).
:Rate<sub>2</sub> is the rate of effusion for the second gas.

:''M<sub>1</sub>'' is the [[Physics:Molar mass|molar mass]] of gas 1
:''M<sub>2</sub>'' is the molar mass of gas 2.}}
{{term|term= '''[[Physics:Gravitational constant|Gravitational constant]]'''}}{{defn|defn=The gravitational constant (also known as the ''universal gravitational constant'', the ''Newtonian constant of gravitation'', or the ''Cavendish gravitational constant''),{{efn|"Newtonian constant of gravitation" is the name introduced for ''G'' by Boys (1894). Use of the term by  T.E. Stern (1928) was misquoted as "Newton's constant of gravitation" in ''Pure Science Reviewed for Profound and Unsophisticated Students'' (1930), in what is apparently the first use of that term. Use of "Newton's constant" (without specifying "gravitation" or "gravity") is more recent, as "Newton's constant" was also
used for the [[Physics:Heat transfer coefficient|heat transfer coefficient]] in [[Physics:Newton's law of cooling|Newton's law of cooling]], but has by now become quite common, e.g.
Calmet et al, ''Quantum Black Holes'' (2013), p. 93;  P. de Aquino, ''Beyond Standard Model Phenomenology at the LHC'' (2013), p. 3.

The name "Cavendish gravitational constant", sometimes "Newton–Cavendish gravitational constant", appears to have been common in the 1970s to 1980s, especially in (translations from) Soviet-era Russian literature, e.g. Sagitov (1970 [1969]), ''Soviet Physics: Uspekhi'' 30 (1987), Issues 1–6, p. 342 [etc.].
"Cavendish constant" and "Cavendish gravitational constant" is also used in Charles W. Misner, Kip S. Thorne, John Archibald Wheeler, "Gravitation",  (1973), 1126f.

Colloquial use of "Big G", as opposed to "little g" for gravitational acceleration dates to the 1960s (R.W. Fairbridge, ''The encyclopedia of atmospheric sciences and astrogeology'', 1967, p. 436; note use of "Big G's" vs. "little g's" as early as the 1940s of the [[Physics:Einstein tensor|Einstein tensor]] ''G''<sub>''μν''</sub> vs. the [[Physics:Metric tensor|metric tensor]] ''g''<sub>''μν''</sub>, ''Scientific, medical, and technical books published in the United States of America: a selected list of titles in print with annotations: supplement of books published 1945–1948'', Committee on American Scientific and Technical Bibliography National Research Council, 1950, p. 26).|name=|group=}} denoted by the letter {{math|''G''}}, is an empirical [[Physics:Physical constant|physical constant]] involved in the calculation of gravitational effects in Sir Isaac Newton's [[Physics:Newton's law of universal gravitation|law of universal gravitation]] and in [[Biography:Albert Einstein|Albert Einstein]]'s [[Physics:General relativity|general theory of relativity]].}}
{{term|term= '''[[Physics:Gravitational energy|Gravitational energy]]'''}}{{defn|defn=Gravitational energy or ''gravitational potential energy'' is the [[Physics:Potential energy|potential energy]] a [[Physics:Mass|mass]]ive object has in relation to another massive object due to [[Physics:Gravity|gravity]]. It is the potential energy associated with the [[Physics:Gravitational field|gravitational field]], which is released (converted into [[Physics:Kinetic energy|kinetic energy]]) when the objects [[Physics:Free fall|fall]] towards each other. Gravitational potential energy increases when two objects are brought further apart.

For two pairwise interacting point particles, the gravitational potential energy <math>U</math> is given by 
:<math>U = -\frac{GMm}{R},</math>
where <math>M</math> and <math>m</math> are the masses of the two particles, <math>R</math> is the distance between them, and <math>G</math> is the [[Physics:Gravitational constant|gravitational constant]].<ref name=gpe>{{cite web|title=Gravitational Potential Energy|url=http://hyperphysics.phy-astr.gsu.edu/hbase/gpot.html|website=hyperphysics.phy-astr.gsu.edu|access-date=10 January 2017}}</ref>

Close to the Earth's surface, the gravitational field is approximately constant, and the gravitational potential energy of an object reduces to

:<math>U = mgh</math>

where <math>m</math> is the object's mass, <math>g = GM_E/R_E^2</math> is the [[Physics:Gravity of Earth|gravity of Earth]], and <math>h</math> is the height of the object's [[Physics:Center of mass|center of mass]] above a chosen reference level.<ref name=gpe/>}}
{{term|term= '''[[Physics:Gravitational field|Gravitational field]]'''}}{{defn|defn=In [[Physics:Physics|physics]], a gravitational field is a model used to explain the influences that a massive body extends into the space around itself, producing a force on another massive body.<ref>{{cite book |first=Richard |last=Feynman |title=The Feynman Lectures on Physics |volume= I |publisher=Addison Wesley Longman |year=1970 |isbn=978-0-201-02115-8 |url=http://www.feynmanlectures.caltech.edu/I_07.html}}</ref> Thus, a gravitational [[Physics:Field|field]] is used to explain [[Physics:Gravity|gravitational]] phenomena, and is measured in [[Newton (unit)|newtons]] per [[Kilogram|kilogram]] (N/kg). In its original concept, [[Physics:Gravity|gravity]] was a [[Physics:Force|force]] between point [[Physics:Mass|mass]]es. Following [[Biography:Isaac Newton|Isaac Newton]], [[Biography:Pierre-Simon Laplace|Pierre-Simon Laplace]] attempted to model gravity as some kind of [[Physics:Radiation|radiation]] field or [[Physics:Fluid|fluid]], and since the 19th century, explanations for gravity have usually been taught in terms of a field model, rather than a point attraction.

In a field model, rather than two particles attracting each other, the particles distort [[Physics:Spacetime|spacetime]] via their mass, and this distortion is what is perceived and measured as a "force".{{citation needed|date=August 2020}}    In such a model one states that matter moves in certain ways in response to the curvature of spacetime,<ref>{{cite book
|title=General Relativity from A to B
|first1=Robert
|last1=Geroch
|publisher=[[Organization:University of Chicago Press|University of Chicago Press]]
|date=1981
|isbn=978-0-226-28864-2
|page=181
|url=https://books.google.com/books?id=UkxPpqHs0RkC&pg=PA181}}
</ref> and that there is either ''no gravitational force'',<ref>{{cite book
|title=Einstein's General Theory of Relativity: with Modern Applications in Cosmology
|first1=Øyvind
|last1=Grøn
|first2=Sigbjørn
|last2=Hervik
|publisher=Springer Japan
|date=2007
|isbn=978-0-387-69199-2
|page=256
|url=https://books.google.com/books?id=IyJhCHAryuUC&pg=PA256}}
</ref> or that gravity is a [[Physics:Fictitious force|fictitious force]].<ref>{{cite book
|title=A Short Course in General Relativity
|edition=3
|first1=J.
|last1=Foster
|first2=J. D.
|last2=Nightingale
|publisher=Springer Science & Business
|date=2006
|isbn=978-0-387-26078-5
|page=55
|url=https://books.google.com/books?id=wtoKZODmoVsC&pg=PA55}}
</ref>

Gravity is distinguished from other forces by its obedience to the [[Astronomy:Equivalence principle|equivalence principle]].}}
{{term|term= '''[[Physics:Gravitational potential|Gravitational potential]]'''}}{{defn|defn=In [[Physics:Classical mechanics|classical mechanics]], the gravitational potential at a location is equal to the [[Physics:Work|work]] ([[Physics:Energy|energy]] transferred) per unit mass that would be needed to move an object to that location from a fixed reference location. It is analogous to the [[Physics:Electric potential|electric potential]] with [[Physics:Mass|mass]] playing the role of [[Physics:Charge|charge]]. The reference location, where the potential is zero, is by convention infinitely far away from any mass, resulting in a negative potential at any finite distance.

In mathematics, the gravitational potential is also known as the [[Newtonian potential]] and is fundamental in the study of [[Potential theory|potential theory]]. It may also be used for solving the electrostatic and magnetostatic fields generated by uniformly charged or polarized ellipsoidal bodies.<ref>{{cite book|title=Electrostatics and magnetostatics of polarized ellipsoidal bodies: the depolarization tensor method|first1=C.E.|last1=Solivérez|edition=1st English|year=2016|publisher=Free Scientific Information|isbn=978-987-28304-0-3}}</ref>}}
{{term|term= '''[[Astronomy:Gravitational wave|Gravitational wave]]'''}}{{defn|defn=Gravitational waves are disturbances in the curvature of [[Physics:Spacetime|spacetime]], generated by accelerated masses, that [[Physics:Wave propagation|propagate as waves]] outward from their source at the [[Physics:Speed of light|speed of light]]. They were proposed by [[Biography:Henri Poincaré|Henri Poincaré]] in 1905<ref>http://www.academie-sciences.fr/pdf/dossiers/Poincare/Poincare_pdf/Poincare_CR1905.pdf</ref> and subsequently predicted in 1916<ref>{{cite journal |author=Einstein, A |title=Näherungsweise Integration der Feldgleichungen der Gravitation |date=June 1916 |url=http://einstein-annalen.mpiwg-berlin.mpg.de/related_texts/sitzungsberichte |journal=Sitzungsberichte der Königlich Preussischen Akademie der Wissenschaften Berlin |volume=part 1 |pages=688–696 |bibcode=1916SPAW.......688E |access-date=2014-11-15 |archive-url=https://web.archive.org/web/20160115224321/http://einstein-annalen.mpiwg-berlin.mpg.de/related_texts/sitzungsberichte |archive-date=2016-01-15 |url-status=dead }}</ref><ref name="Gravitationswellen">{{cite journal |author=Einstein, A |title=Über Gravitationswellen |date=1918 |url=http://einstein-annalen.mpiwg-berlin.mpg.de/related_texts/sitzungsberichte |journal=Sitzungsberichte der Königlich Preussischen Akademie der Wissenschaften Berlin |volume=part 1 |pages=154–167 |bibcode=1918SPAW.......154E |access-date=2014-11-15 |archive-url=https://web.archive.org/web/20160115224321/http://einstein-annalen.mpiwg-berlin.mpg.de/related_texts/sitzungsberichte |archive-date=2016-01-15 |url-status=dead }}</ref> by [[Biography:Albert Einstein|Albert Einstein]] on the basis of his [[Physics:General relativity|general theory of relativity]].<ref>{{cite web |last=Finley |first=Dave |title=Einstein's gravity theory passes toughest test yet: Bizarre binary star system pushes study of relativity to new limits |url=http://phys.org/news/2013-04-einstein-gravity-theory-toughest-bizarre.html |publisher=Phys.Org}}</ref><ref>[http://www.dpf99.library.ucla.edu/session14/barish1412.pdf The Detection of Gravitational Waves using LIGO, B. Barish] {{webarchive|url=https://web.archive.org/web/20160303205650/http://www.dpf99.library.ucla.edu/session14/barish1412.pdf |date=2016-03-03 }}</ref> Gravitational waves transport energy as ''gravitational radiation'', a form of [[Physics:Radiant energy|radiant energy]] similar to [[Physics:Electromagnetic radiation|electromagnetic radiation]].<ref>{{cite journal |title=On gravitational waves |journal=Journal of the Franklin Institute |date=January 1937 |last1=Einstein |first1=Albert |last2=Rosen |first2=Nathan |volume=223 |issue=1 |pages=43–54 |doi=10.1016/S0016-0032(37)90583-0 |bibcode=1937FrInJ.223...43E }}</ref> [[Physics:Newton's law of universal gravitation|Newton's law of universal gravitation]], part of [[Physics:Classical mechanics|classical mechanics]], does not provide for their existence, since that law is predicated on the assumption that physical interactions propagate instantaneously (at infinite speed){{snd}}showing one of the ways the methods of classical physics are unable to explain phenomena associated with relativity.}}
{{term|term= '''[[Physics:Gravity|Gravity]]'''}}{{defn|defn= Or ''gravitation'', is a [[Earth:List of natural phenomena|natural phenomenon]] by which all things with [[Physics:Mass|mass]] or [[Physics:Energy|energy]]—including [[Astronomy:Planet|planet]]s, [[Astronomy:Star|star]]s, [[Astronomy:Galaxy|galaxies]], and even [[Physics:Light|light]]<ref name="Comins">{{cite book
 | last1 = Comins
 | first1 = Neil F.
 | last2 = Kaufmann
 | first2 = William J.
 | title = Discovering the Universe: From the Stars to the Planets
 | publisher = MacMillan
 | date = 2008
 | page = 347
 | url = https://books.google.com/books?id=J1d9HJHlISkC&pg=PA347
 | isbn = 978-1429230421
 | bibcode = 2009dufs.book.....C
 }}</ref>—are brought toward (or ''gravitate'' toward) one another. On [[Astronomy:Earth|Earth]], gravity gives [[Physics:Weight|weight]] to [[Philosophy:Physical body|physical objects]], and the [[Astronomy:Moon|Moon]]'s [[Physics:Gravitation of the Moon|gravity]] causes the ocean [[Astronomy:Tide|tide]]s. The gravitational attraction of the original gaseous matter present in the [[Astronomy:Universe|Universe]] caused it to begin [[Physics:Coalescence|coalescing]] and [[Astronomy:Star formation|forming stars]] and caused the stars to group together into galaxies, so gravity is responsible for many of the large-scale structures in the Universe. Gravity has an infinite range, although its effects become increasingly weaker as objects get further away.}}
{{term|term= '''[[Physics:Ground state|Ground state]]'''}}{{defn|defn=The ground state of a [[Physics:Quantum mechanics|quantum-mechanical]] system is its lowest-[[Physics:Energy|energy]] [[Physics:Stationary state|state]]; the energy of the ground state is known as the [[Physics:Zero-point energy|zero-point energy]] of the system. An [[Physics:Excited state|excited state]] is any state with energy greater than the ground state. In [[Physics:Quantum field theory|quantum field theory]], the ground state is usually called the [[Physics:Vacuum state|vacuum state]] or the [[Physics:Vacuum#The quantum-mechanical vacuum|vacuum]].}}

{{glossary end}}

==H==
{{glossary}}

{{term|term= '''[[Physics:Half-life|Half-life]]'''}}{{defn|defn=The period at which one-half of a quantity of an unstable isotope has decayed into other elements; the time at which half of a substance has diffused out of or otherwise reacted in a system.}}
{{term|term= '''[[Engineering:Haptic technology|Haptic]]'''}}{{defn|defn=Tactile feedback technology using the operator's sense of touch. Also sometimes applied to robot manipulators with their own touch sensitivity.}} 
{{term|term= '''[[Physics:Hardness|Hardness]]'''}}{{defn|defn=Is a measure of the resistance to localized plastic deformation induced by either mechanical [[Physics:Indentation hardness|indentation]] or [[Physics:Abrasion (mechanical)|abrasion]]. Some materials (e.g. [[Chemistry:Metal|metal]]s) are harder than others (e.g. [[Chemistry:Plastic|plastic]]s, [[Biology:Wood|wood]]). Macroscopic hardness is generally characterized by strong intermolecular bonds, but the behavior of solid materials under force is complex; therefore, there are different measurements of hardness: ''scratch hardness'', ''indentation hardness'', and ''rebound hardness''. Hardness is dependent on [[Physics:Ductility|ductility]], [[Physics:Elasticity|elastic]] [[Physics:Stiffness|stiffness]], [[Physics:Plasticity|plasticity]], [[Physics:Deformation (mechanics)|strain]], [[Physics:Strength of materials|strength]], [[Physics:Toughness|toughness]], [[Physics:Viscoelasticity|viscoelasticity]], and [[Physics:Viscosity|viscosity]].}}
{{term|term= '''[[Harmonic mean]]'''}}{{defn|defn=In [[Mathematics|mathematics]], the harmonic mean (sometimes called the subcontrary mean) is one of several kinds of [[Average|average]], and in particular, one of the [[Pythagorean means]]. Typically, it is appropriate for situations when the average of [[Rate (mathematics)|rate]]s is desired.

The harmonic mean can be expressed as the [[Multiplicative inverse|reciprocal]] of the [[Arithmetic mean|arithmetic mean]] of the reciprocals of the given set of observations. As a simple example, the harmonic mean of 1, 4, and 4 is
: <math>\left(\frac{1^{-1} + 4^{-1} + 4^{-1}}{3}\right)^{-1} = \frac{3}{\frac{1}{1} + \frac{1}{4} + \frac{1}{4}} = \frac{3}{1.5} = 2\,.</math>}}
{{term|term= '''[[Physics:Heat|Heat]]'''}}{{defn|defn=In [[Physics:Thermodynamics|thermodynamics]], heat is [[Physics:Energy|energy]] in transfer to or from a thermodynamic system, by mechanisms other than [[Physics:Work (thermodynamics)|thermodynamic work]] or [[Physics:Mass transfer|transfer of matter]].<ref>
Reif (1965):
"[in the special case of purely thermal interaction between two system:] The mean energy transferred from one system to the other as a result of purely thermal interaction is called 'heat'" (p. 67).
the quantity {{mvar|Q}} [...] is simply a measure of the mean energy change ''not'' due to the change of external parameters. [...] splits the total mean energy change into a part W due to mechanical interaction and a part {{mvar|Q}} due to thermal interaction  [...] by virtue of [the definition {{math|1=Δ''U'' = ''Q'' − ''W''}}, present notation, physics sign convention], both heat and work have the dimensions of energy" (p. 73). C.f.: "heat is thermal energy in transfer" Stephen J. Blundell, Katherine M. Blundell, ''Concepts in Thermal Physics'' (2009),  [https://books.google.ch/books?id=YE9uBAAAQBAJ&pg=PA13  p. 13] {{Webarchive|url=https://web.archive.org/web/20180624150432/https://books.google.ch/books?id=YE9uBAAAQBAJ&pg=PA13 |date=24 June 2018 }}.
</ref><ref>''Thermodynamics and an Introduction to Thermostatics, 2nd Edition,'' by Herbert B. Callen, 1985, http://cvika.grimoar.cz/callen/ {{Webarchive|url=https://web.archive.org/web/20181017152028/http://cvika.grimoar.cz/callen/ |date=17 October 2018 }} or http://keszei.chem.elte.hu/1alapFizkem/H.B.Callen-Thermodynamics.pdf {{Webarchive|url=https://web.archive.org/web/20161230040339/http://keszei.chem.elte.hu/1alapFizkem/H.B.Callen-Thermodynamics.pdf |date=30 December 2016 }} , p. 8: Energy may be transferred via ... work. "But it is equally possible to transfer energy via the hidden atomic modes of motion as well as via those that happen to be macroscopically observable. An energy transfer via the hidden atomic modes is called ''heat''."</ref><ref>[[Biography:Max Born|Born, M.]] (1949), p. 31.</ref><ref>Pippard, A.B. (1957/1966), p. 16.</ref><ref>[[Biography:Lev Landau|Landau, L.]], [[Biography:Evgeny Lifshitz|Lifshitz, E.M.]] (1958/1969), p. 43</ref><ref>[[Biography:Herbert Callen|Callen, H.B.]] (1960/1985), pp. 18–19.</ref><ref>Bailyn, M. (1994), p. 82.</ref>}}
{{term|term= '''[[Physics:Heat transfer|Heat transfer]]'''}}{{defn|defn=Is a discipline of [[Chemistry:Thermal engineering|thermal engineering]] that concerns the generation, use, conversion, and exchange of [[Physics:Thermal energy|thermal energy]] ([[Physics:Heat|heat]]) between physical systems. Heat transfer is classified into various mechanisms, such as [[Physics:Thermal conduction|thermal conduction]], [[Physics:Convection (heat transfer)|thermal convection]], [[Physics:Thermal radiation|thermal radiation]], and transfer of energy by phase changes. Engineers also consider the transfer of mass of differing chemical species, either cold or hot, to achieve heat transfer. While these mechanisms have distinct characteristics, they often occur simultaneously in the same system.}}
{{term|term= '''[[Physics:Helmholtz free energy|Helmholtz free energy]]'''}}{{defn|defn=In [[Physics:Thermodynamics|thermodynamics]], the Helmholtz free energy (or Helmholtz energy) is a [[Thermodynamic potential|thermodynamic potential]] that measures the useful [[Physics:Work (thermodynamics)|work]] obtainable from a [[Closed system|closed]] [[Physics:Thermodynamic system|thermodynamic system]] at a constant [[Physics:Temperature|temperature]] and [[Physics:Volume|volume]] ([[Physics:Isothermal process|isothermal]], [[Physics:Isochoric process|isochoric]]). The negative of the change in the Helmholtz energy during a process is equal to the maximum amount of work that the system can perform in a thermodynamic process in which volume is held constant. If the volume were not held constant, part of this work would be performed as boundary work. This makes the Helmholtz energy useful for systems held at constant volume. Furthermore, at constant temperature, the Helmholtz free energy is minimized at equilibrium.}}
{{term|term= '''[[Henderson–Hasselbalch equation]]'''}}{{defn|defn=In [[Chemistry:Chemistry|chemistry]] and [[Biology:Biochemistry|biochemistry]], the Henderson–Hasselbalch equation 
:<math chem>\ce{pH} = \ce{p}K_\ce{a} + \log_{10}  \left( \frac{[\ce{Base}]}{[\ce{Acid}]} \right)</math>
can be used to estimate the [[Chemistry:PH|pH]] of a [[Chemistry:Buffer solution|buffer solution]]. The numerical value of the [[Chemistry:Acid dissociation constant|acid dissociation constant]], ''K''<sub>a</sub>, of the acid is known or assumed. The pH is calculated for given values of the concentrations of the acid, HA and of a salt, MA, of its conjugate base, A<sup>−</sup>; for example, the solution may contain [[Chemistry:Acetic acid|acetic acid]] and [[Chemistry:Sodium acetate|sodium acetate]].}}
{{term|term= '''[[Physics:Henry's law|Henry's law]]'''}}{{defn|defn=In physical [[Chemistry:Chemistry|chemistry]], Henry's law is a [[Physics:Gas laws|gas law]] that states that the amount of dissolved gas in a liquid is proportional to its [[Physics:Partial pressure|partial pressure]] above the liquid. The proportionality factor is called Henry's law constant. It was formulated by the English chemist William Henry, who studied the topic in the early 19th century.}}
{{term|term= '''[[Hertz]] '''}}{{defn|defn=The SI unit of frequency, one cycle per second.}}
{{term|term= '''[[Stewart platform|Hexapod]]'''}}{{defn|defn=(platform) – a movable platform using six linear actuators. Often used in [[Flight simulator|flight simulator]]s they also have applications as a robotic manipulator.}} 
{{term|term= '''[[Hexapod (robotics)|Hexapod]]'''}}{{defn|defn=(walker) – a six-legged walking robot, using a simple [[Biology:Hexapoda|insect-like]] locomotion.}} 
{{term|term= '''[[Engineering:Hoist (device)|Hoist]]'''}}{{defn|defn=Is a device used for lifting or lowering a load by means of a drum or lift-wheel around which rope or chain wraps. It may be manually operated, electrically or pneumatically driven and may use chain, fiber or wire [[Engineering:Rope|rope]] as its lifting medium. The most familiar form is an [[Engineering:Elevator|elevator]], the car of which is raised and lowered by a hoist mechanism. Most hoists couple to their loads using a [[Engineering:Lifting hook|lifting hook]]. Today, there are a few governing bodies for the North American overhead hoist industry which include the Hoist Manufactures Institute ([https://mhi.org/hmi HMI]), ASME, and the Occupational Safety and Health Administration ([https://osha.gov OSHA]). HMI is a product counsel of the Material Handling Industry of America consisting of hoist manufacturers promoting safe use of their products.}}
{{term|term= '''[[Horsepower]]'''}}{{defn|defn=In measurement systems that use feet, the unit of power.}}
{{term|term= '''[[Engineering:Hot working|Hot working]]'''}}{{defn|defn=Or ''hot forming'', any metal-working procedure (such as forging, rolling, extruding, etc.) carried out above the metal's recrystallization temperature.}}
{{term|term= '''[[Physics:Huygens–Fresnel principle|Huygens–Fresnel principle]]'''}}{{defn|defn=The Huygens–Fresnel principle (named after Dutch [[Physicist|physicist]] [[Biography:Christiaan Huygens|Christiaan Huygens]] and {{wipe|France}} physicist [[Biography:Augustin-Jean Fresnel|Augustin-Jean Fresnel]]) is a method of analysis applied to problems of [[Physics:Wave propagation|wave propagation]] both in the far-field limit and in near-field [[Physics:Diffraction|diffraction]] and also [[Physics:Reflection|reflection]]. It states that every point on a [[Wavefront|wavefront]] is itself the source of spherical wavelets, and the secondary wavelets emanating from different points mutually interfere.<ref name="MathPages">{{cite web | title=Huygens' Principle | website=MathPages | url=https://www.mathpages.com/home/kmath242/kmath242.htm | access-date=2017-10-03}}</ref> The sum of these spherical wavelets forms the wavefront.}}
{{term|term= '''[[Physics:Hydraulics|Hydraulics]]'''}}{{defn|defn=The study of fluid flow, or the generation of mechanical force and movement by liquid under pressure.}} 
{{term|term= '''[[Chemistry:Hydrocarbon|Hydrocarbon]]'''}}{{defn|defn=A compound containing hydrogen and carbon atoms only; petroleum is made of hydrocarbons.}}

{{glossary end}}

==I==
{{glossary}}

{{term|term= '''Ice point'''}}{{defn|defn=The [[Physics:Freezing point|freezing point]] of pure [[Chemistry:Water|water]] at one [[Astronomy:Atmosphere|atmosphere]]; 0°C (32°F).<ref>[https://en.wiktionary.org/wiki/ice_point Wiktionary]</ref>}}
{{term|term= '''[[Physics:Ideal gas|Ideal gas]]'''}}{{defn|defn=A model for gases that ignores inter-molecular forces. Most gases are approximately ideal at some high temperature and low pressure. }} 
{{term|term= '''[[Physics:Ideal gas constant|Ideal gas constant]]'''}}{{defn|defn=The constant in the gas law that relates pressure, volume and temperature.}} 
{{term|term= '''[[Physics:Ideal gas law|Ideal gas law]]'''}}{{defn|defn=Also called the general gas equation, is the [[Physics:Equation of state|equation of state]] of a hypothetical [[Physics:Ideal gas|ideal gas]]. It is a good approximation of the behavior of many [[Physics:Gas|gas]]es under many conditions, although it has several limitations. It was first stated by [[Biography:Benoît Paul Émile Clapeyron|Benoît Paul Émile Clapeyron]] in 1834 as a combination of the empirical [[Boyle's law]], [[Physics:Charles's law|Charles's law]], [[Physics:Avogadro's law|Avogadro's law]], and [[Physics:Gay-Lussac's law|Gay-Lussac's law]].<ref>
{{Cite journal
 | year = 1834
 | title = Mémoire sur la puissance motrice de la chaleur
 | journal = Journal de l'École Polytechnique
 | volume = XIV | pages = 153–90
|language=fr}} [http://gallica.bnf.fr/ark:/12148/bpt6k4336791/f157.table Facsimile at the Bibliothèque nationale de France (pp.&nbsp;153–90)].</ref> The ideal gas law is often written in an empirical form:

:<math>PV = nRT</math>

where <math>P</math>, <math>V</math> and <math>T</math> are the [[Physics:Pressure|pressure]], [[Physics:Volume|volume]] and [[Physics:Thermodynamic temperature|temperature]]; <math>n</math> is the [[Physics:Amount of substance|amount of substance]]; and <math>R</math> is the [[Physics:Ideal gas constant|ideal gas constant]]. It is the same for all gases.
It can also be derived from the microscopic [[Physics:Kinetic theory of gases|kinetic theory]], as was achieved (apparently independently) by [[Biography:August Krönig|August Krönig]] in 1856<ref>
{{Cite journal
 | year = 1856
 | title = Grundzüge einer Theorie der Gase
 | journal = [[Physics:Annalen der Physik|Annalen der Physik und Chemie]]
 | volume = 99 | pages = 315–22
 | doi = 10.1002/andp.18561751008
|bibcode = 1856AnP...175..315K
 | issue = 10 |language=de| url = https://zenodo.org/record/1423642
 }} [http://gallica.bnf.fr/ark:/12148/bpt6k15184h/f327.table Facsimile at the Bibliothèque nationale de France (pp.&nbsp;315–22)].</ref> and [[Biography:Rudolf Clausius|Rudolf Clausius]] in 1857.<ref>
{{Cite journal
 | year = 1857
 | title = Ueber die Art der Bewegung, welche wir Wärme nennen
 | journal = Annalen der Physik und Chemie
 | volume = 176 | pages = 353–79
 | doi = 10.1002/andp.18571760302
|bibcode = 1857AnP...176..353C
 | issue = 3 |language=de| url = https://zenodo.org/record/1423644
 }} [http://gallica.bnf.fr/ark:/12148/bpt6k15185v/f371.table Facsimile at the Bibliothèque nationale de France (pp.&nbsp;353–79)].</ref>}} 
{{term|term= '''[[Identity (mathematics)|Identity]]'''}}{{defn|defn=In [[Mathematics|mathematics]], an identity is an [[Equality (mathematics)|equality]] relating one mathematical expression ''A''&nbsp;to another mathematical expression&nbsp;''B'', such that ''A'' and ''B'' (which might contain some [[Variable (mathematics)|variables]]) produce the same value for all values of the variables within a certain range of validity.<ref>{{Cite web|url=https://mathvault.ca/math-glossary/#identity|title=The Definitive Glossary of Higher Mathematical Jargon — Identity|date=2019-08-01|website=Math Vault|access-date=2019-12-01}}</ref><ref>{{Cite web|url=https://www.mathwords.com/i/identity.htm|title=Mathwords: Identity|website=www.mathwords.com|access-date=2019-12-01}}</ref> In other words, ''A''&nbsp;=&nbsp;''B'' is an identity if ''A'' and ''B'' define the same [[Function (mathematics)|functions]], and an identity is an equality between functions that are differently defined. For example, <math>(a+b)^2 = a^2 + 2ab + b^2</math> and <math>\cos^2\theta + \sin^2\theta =1</math> are identities.<ref>[https://www.mathwords.com/i/identity.htm "Mathwords: Identity".] www.mathwords.com. Retrieved 2019-12-01.</ref> Identities are sometimes indicated by the [[Triple bar|triple bar]] symbol {{math|≡}} instead of {{math|1==}}, the [[Equals sign|equals sign]].<ref>{{Cite web|url=https://www.mathopenref.com/identity.html|title=Identity - math word definition - Math Open Reference|website=www.mathopenref.com|access-date=2019-12-01}}</ref>}}
{{term|term= '''[[Physics:Electrical impedance|Impedance (electrical)]]'''}}{{defn|defn=In [[Electrical engineering|electrical engineering]], electrical impedance is the measure of the opposition that a [[Physics:Electrical circuit|circuit]] presents to a [[Physics:Electric current|current]] when a [[Physics:Voltage|voltage]] is applied.}}
{{term|term= '''[[Engineering:Inclined plane|Inclined plane]]'''}}{{defn|defn=Also known as a ''ramp'', is a flat supporting surface tilted at an  angle, with one end higher than the other, used as an aid for raising or lowering a load.<ref name="Cole">{{cite book
 | last = Cole
 | first = Matthew
 | title = Explore science, 2nd Ed.
 | publisher = Pearson Education
 | year = 2005
 | page = 178
 | url = https://books.google.com/books?id=RhuciGEQ1G8C&pg=PA178
 | isbn = 978-981-06-2002-8}}</ref><ref>{{cite book
 | title = Merriam-Webster's collegiate dictionary, 11th Ed.
 | publisher = Merriam-Webster
 | year = 2003
 | page = [https://archive.org/details/merriamwebstersc00merr_6/page/629 629]
 | url = https://archive.org/details/merriamwebstersc00merr_6
 | url-access = registration
 | quote = inclined plane definition dictionary.
 | isbn = 978-0-87779-809-5}}</ref><ref name="Edinformatics">{{cite web
 | title = The Inclined Plane
 | work = Math and science activity center
 | publisher = Edinformatics
 | year = 1999
 | url = http://www.edinformatics.com/math_science/simple_machines/inclined_plane.htm
 | access-date = March 11, 2012}}</ref> The inclined plane is one of the six classical [[Engineering:Simple machine|simple machine]]s defined by Renaissance scientists. Inclined planes are widely used to move heavy loads over vertical obstacles; examples vary from a ramp used to load goods into a truck, to a person walking up a pedestrian ramp, to an automobile or railroad train climbing a grade.<ref name="Edinformatics" />}}
{{term|term= '''Indefinite integral'''}}{{defn|defn=A [[Function (mathematics)|function]] whose [[Derivative|derivative]] is a given function; an [[Antiderivative|antiderivative]].<ref>https://en.wiktionary.org/wiki/indefinite_integral Wiktionary</ref>}}{{term|term= '''[[Physics:Inductance|Inductance]]'''}}{{defn|defn=In [[Physics:Electromagnetism|electromagnetism]] and [[Engineering:Electronics|electronics]], inductance is the tendency of an [[Physics:Electrical conductor|electrical conductor]] to oppose a change in the [[Physics:Electric current|electric current]] flowing through it. The flow of electric current creates a [[Physics:Magnetic field|magnetic field]] around the conductor. The field strength depends on the magnitude of the current, and follows any changes in current. From [[Physics:Faraday's law of induction|Faraday's law of induction]], any change in magnetic field through a circuit induces an [[Physics:Electromotive force|electromotive force]] (EMF) ([[Physics:Voltage|voltage]]) in the conductors, a process known as [[Physics:Electromagnetic induction|electromagnetic induction]]. This induced voltage created by the changing current has the effect of opposing the change in current. This is stated by [[Physics:Lenz's law|Lenz's law]], and the voltage is called ''back EMF''. Inductance is defined as the ratio of the induced voltage to the rate of change of current causing it. It is a proportionality factor that depends on the geometry of circuit conductors and the magnetic permeability of nearby materials.<ref>{{cite book |author1=Serway, A. Raymond |author2=Jewett, John W. |author3=Wilson, Jane |author4=Wilson, Anna |author5=Rowlands, Wayne |title=Physics for global scientists and engineers |isbn=9780170355520 |page=901 |edition=2ndition |chapter=32 |date=2016-10-01 |df=dmy-all}}</ref> An [[Engineering:Electronic component|electronic component]] designed to add inductance to a circuit is called an [[Engineering:Inductor|inductor]]. It typically consists of a [[Engineering:Electromagnetic coil|coil]] or helix of wire.}}
{{term|term= '''[[Engineering:Inductor|Inductor]]'''}}{{defn|defn=An inductor, also called a coil, choke, or reactor, is a passive two-terminal [[Engineering:Electronic component|electrical component]] that stores energy in a [[Physics:Magnetic field|magnetic field]] when [[Physics:Electric current|electric current]] flows through it.<ref>{{cite book|last1=Alexander|first1=Charles|last2=Sadiku|first2=Matthew|title=Fundamentals of Electric Circuits|publisher=McGraw-Hill|page=211|edition=3}}</ref> An inductor typically consists of an insulated wire wound into a [[Engineering:Electromagnetic coil|coil]].}}
{{term|term= '''[[Industrial engineering]]'''}}{{defn|defn=Is an engineering profession that is concerned with the optimization of complex [[Engineering:Process (engineering)|processes]], [[Philosophy:System|system]]s, or organizations by developing, improving and implementing integrated systems of people, money, knowledge, information and equipment. Industrial engineers use specialized [[Philosophy:Knowledge|knowledge]] and skills in the mathematical, physical and social sciences, together with the principles and methods of [[Engineering:Engineering analysis|engineering analysis]] and design, to specify, predict, and evaluate the results obtained from systems and processes.<ref>Salvendy, Gabriel. Handbook of Industrial Engineering. John Wiley & Sons, Inc; 3rd edition p. 5</ref> From these results, they are able to create new systems, processes or situations for the useful coordination of [[Social:Wage labour|labour]], materials and machines and also improve the [[Finance:Quality (business)|quality]] and [[Finance:Productivity|productivity]] of systems, physical or social.<ref>{{Cite web|url=http://www.iienet2.org/details.aspx?id=716|title=What IEs Do|website=www.iienet2.org|access-date=September 24, 2015}}</ref>}}
{{term|term= '''[[Physics:Inertia|Inertia]]'''}}{{defn|defn=Is the resistance of any physical [[Philosophy:Physical body|object]] to any change in its [[Physics:Velocity|velocity]]. This includes changes to the object's [[Physics:Speed|speed]], or [[Relative direction|direction]] of motion. 
An aspect of this property is the tendency of objects to keep moving in a straight line at a constant speed, when no [[Physics:Force|force]]s act upon them.}}
{{term|term= '''[[Physics:Infrasound|Infrasound]]'''}}{{defn|defn=Infrasound, sometimes referred to as ''low-frequency sound'', describes sound waves with a frequency below the lower limit of audibility (generally 20&nbsp;Hz). Hearing becomes gradually less sensitive as frequency decreases, so for humans to perceive infrasound, the [[Physics:Sound pressure|sound pressure]] must be sufficiently high. The ear is the primary organ for sensing low sound, but at higher intensities it is possible to feel infrasound vibrations in various parts of the body.}}
{{term|term= '''[[Integral]]'''}}{{defn|defn=In [[Mathematics|mathematics]], an integral assigns numbers to functions in a way that describes displacement, area, volume, and other concepts that arise by combining [[Infinitesimal|infinitesimal]] data. The process of finding integrals is called ''integration''. Along with [[Derivative|differentiation]], integration is a fundamental operation of calculus,<ref group="lower-alpha">Integral calculus is a very well established mathematical discipline for which there are many sources. See {{Harvnb|Apostol|1967}} and {{Harvnb|Anton|Bivens|Davis|2016}}, for example.</ref> and serves as a tool to solve problems in mathematics and [[Physics:Physics|physics]] involving the area of an arbitrary shape, the length of a curve, and the volume of a solid, among others.}}
{{term|term= '''[[Integral transform]]'''}}{{defn|defn=In [[Mathematics|mathematics]], an integral transform maps a [[Function (mathematics)|function]] from its original [[Function space|function space]] into another function space via [[Integral|integration]], where some of the properties of the original function might be more easily characterized and manipulated than in the original function space. The transformed function can generally be mapped back to the original function space using the ''inverse transform''.}}
{{term|term= '''[[International System of Units]]'''}}{{defn|defn=The  International System of Units (SI, abbreviated from the [[Social:French language|French]] ''{{lang|fr|Système international (d'unités)}}'') is the modern form of the [[Metric system|metric system]]. It is the only [[System of measurement|system of measurement]] with an official status in nearly every country in the world. It comprises a [[Coherence (units of measurement)|coherent]] system of units of measurement starting with seven [[SI base unit|base unit]]s, which are the [[Second|second]] (the unit of [[Time|time]] with the symbol s), [[Metre|metre]] ([[Physics:Length|length]], m), [[Kilogram|kilogram]] ([[Physics:Mass|mass]], kg), [[Ampere|ampere]] ([[Physics:Electric current|electric current]], A), [[Kelvin|kelvin]] ([[Physics:Thermodynamic temperature|thermodynamic temperature]], K), [[Mole (unit)|mole]] ([[Physics:Amount of substance|amount of substance]], mol), and [[Candela|candela]] ([[Physics:Luminous intensity|luminous intensity]], cd). The system allows for an unlimited number of additional units, called [[SI derived unit|derived units]], which can always be represented as products of powers of the base units.<ref group="Note">For example, the SI unit of [[Physics:Velocity|velocity]] is the metre per second, m⋅s<sup>−1</sup>; of [[Physics:Acceleration|acceleration]] is the metre per second squared, m⋅s<sup>−2</sup>; etc.</ref> Twenty-two derived units have been provided with special names and symbols.<ref group="Note">For example the [[Newton (unit)|newton]] (N), the unit of [[Physics:Force|force]], equivalent to kg⋅m⋅s<sup>−2</sup>; the [[Joule|joule]] (J), the unit of [[Physics:Energy|energy]], equivalent to kg⋅m<sup>2</sup>⋅s<sup>−2</sup>, etc. The most recently named derived unit, the [[Katal|katal]], was defined in 1999.</ref> The seven base units and the 22 derived units with special names and symbols may be used in combination to express other derived units,<ref group="Note">For example, the recommended unit for the [[Physics:Electric field|electric field strength]] is the volt per metre, V/m, where the [[Volt|volt]] is the derived unit for [[Physics:Voltage|electric potential difference]]. The volt per metre is equal to kg⋅m⋅s<sup>−3</sup>⋅A<sup>−1</sup> when expressed in terms of base units.</ref> which are adopted to facilitate measurement of diverse quantities. The SI system also provides twenty [[Metric prefix|prefix]]es to the unit names and unit symbols that may be used when specifying power-of-ten (i.e. decimal) multiples and sub-multiples of SI units. The SI is intended to be an evolving system; units and prefixes are created and unit definitions are modified through international agreement as the technology of [[Measurement|measurement]] progresses and the precision of measurements improves.}}
{{term|term= '''[[Interval estimation]]'''}}{{defn|defn=In [[Statistics|statistics]], interval estimation is the use of [[Sample (statistics)|sample data]] to calculate an [[Interval (mathematics)|interval]] of possible values of an unknown population parameter; this is in contrast to [[Point estimation|point estimation]], which gives a single value. [[Biography:Jerzy Neyman|Jerzy Neyman]] (1937) identified interval estimation ("estimation by interval") as distinct from [[Point estimation|point estimation]] ("estimation by unique estimate"). In doing so, he recognized that then-recent work quoting results in the form of an [[Estimator|estimate]] plus-or-minus a [[Standard deviation|standard deviation]] indicated that interval estimation was actually the problem statisticians really had in mind.}}
{{term|term= '''[[Chemistry:Inorganic chemistry|Inorganic chemistry]]'''}}{{defn|defn=Deals with [[Chemistry:Chemical synthesis|synthesis]] and behavior of [[Chemistry:Inorganic compound|inorganic]] and [[Chemistry:Organometallic chemistry|organometallic]] compounds. This field covers [[Chemistry:Chemical compound|chemical compound]]s that are not carbon-based, which are the subjects of [[Chemistry:Organic chemistry|organic chemistry]]. The distinction between the two disciplines is far from absolute, as there is much overlap in the subdiscipline of [[Chemistry:Organometallic chemistry|organometallic chemistry]]. It has applications in every aspect of the chemical industry, including [[Chemistry:Catalysis|catalysis]], [[Physics:Materials science|materials science]], pigments, [[Biology:Surfactant|surfactant]]s, [[Physics:Coating|coating]]s, medications, fuels, and [[Earth:Agriculture|agriculture]].<ref>{{cite web | publisher = American Chemical Society | title = Careers in Chemistry: Inorganic Chemistry | url = http://portal.acs.org/portal/acs/corg/content?_nfpb=true&_pageLabel=PP_ARTICLEMAIN&node_id=1188&content_id=CTP_003393&use_sec=true&sec_url_var=region1&__uuid=2fe23bbd-4dcd-4087-b35c-3a886576a618 | url-status=dead | archive-url = https://web.archive.org/web/20121029023510/http://portal.acs.org/portal/acs/corg/content?_nfpb=true | archive-date = 2012-10-29 }}</ref>}}{{term|term= '''[[Physics:Ion|Ion]]'''}}{{defn|defn=Is a [[Physics:Particle|particle]], [[Physics:Atom|atom]] or [[Physics:Molecule|molecule]] with a net [[Physics:Electric charge|electrical charge]]. The charge of the electron is considered negative by convention. The negative charge of an ion is equal and opposite to charged proton(s) considered positive by convention. The net charge of an ion is non-zero due to its total number of [[Physics:Electron|electron]]s being unequal to its total number of [[Physics:Proton|proton]]s.}}
{{term|term= '''[[Chemistry:Ionic bonding|Ionic bonding]]'''}}{{defn|defn=Is a type of [[Chemistry:Chemical bond|chemical bond]]ing that involves the [[Physics:Coulomb's law|electrostatic attraction]] between oppositely charged [[Physics:Ion|ion]]s, or between two atoms with sharply different electronegativities,<ref>{{Cite book|chapter-url=https://doi.org/10.1351/goldbook.IT07058|doi = 10.1351/goldbook.IT07058|chapter = Ionic bond|title = IUPAC Compendium of Chemical Terminology|year = 2009|isbn = 978-0-9678550-9-7}}</ref> and is the primary interaction occurring in [[Physics:Ionic compound|ionic compound]]s. It is one of the main types of bonding along with [[Chemistry:Covalent bond|covalent bond]]ing and [[Chemistry:Metallic bonding|metallic bonding]]. Ions are atoms (or groups of atoms) with an electrostatic charge. Atoms that gain electrons make negatively charged ions (called anions). Atoms that lose electrons make positively charged ions (called [[Physics:Cations|cations]]). This transfer of electrons is known as ''electrovalence'' in contrast to [[Chemistry:Covalent bond|covalence]]. In the simplest case, the cation is a [[Chemistry:Metal|metal]] atom and the anion is a [[Chemistry:Nonmetal|nonmetal]] atom, but these ions can be of a more complex nature, e.g. molecular ions like {{chem|NH|4|+}} or {{chem|SO|4|2−}}. In simpler words, an ionic bond results from the transfer of electrons from a [[Chemistry:Metal|metal]] to a non-metal in order to obtain a full valence shell for both atoms.}}
{{term|term= '''[[Physics:Ionization|Ionization]]'''}}{{defn|defn=Ionization or ''ionisation'' is the process by which an [[Physics:Atom|atom]] or a [[Physics:Molecule|molecule]] acquires a negative or positive [[Physics:Electric charge|charge]] by gaining or losing [[Physics:Electron|electron]]s, often in conjunction with other chemical changes. The resulting electrically charged atom or molecule is called an [[Physics:Ion|ion]]. Ionization can result from the loss of an electron after collisions with [[Physics:Subatomic particle|subatomic particle]]s, collisions with other atoms, molecules and ions, or through the interaction with [[Physics:Electromagnetic radiation|electromagnetic radiation]]. Heterolytic bond cleavage and heterolytic [[Chemistry:Substitution reaction|substitution reaction]]s can result in the formation of ion pairs. Ionization can occur through radioactive decay by the [[Physics:Internal conversion|internal conversion]] process, in which an excited nucleus transfers its energy to one of the inner-shell electrons causing it to be ejected.}}
{{term|term= '''[[Physics:Isotope|Isotope]]'''}}{{defn|defn=Isotopes are variants of a particular [[Chemistry:Chemical element|chemical element]] which differ in [[Physics:Neutron number|neutron number]], and consequently in nucleon number. All isotopes of a given element have the same number of [[Physics:Proton|proton]]s but different numbers of neutrons in each [[Physics:Atom|atom]].<ref>{{cite web | title = Isotope | publisher = Encyclopedia Britannica | url = https://www.britannica.com/science/isotope|first = Gregory F. |last = Herzog|date = 2 June 2020}}</ref>}}

{{glossary end}}

==J==
{{glossary}}

{{term|term= '''J/psi meson'''}}{{defn|defn=The '''{{SubatomicParticle|J/psi}}''' ('''J/psi''') '''meson''' {{IPAc-en|ˈ|dʒ|eɪ|_|ˈ|s|aɪ|_|ˈ|m|iː|z|ɒ|n|}} or '''psion'''<ref><!-- This appears to be a circular reference to this article. -->{{cite book |url=https://books.google.com/books?id=8AD3GDoVaMkC&q=psion+meson+-wikipedia&pg=PA462 |title=[no title cited] |isbn=9780444511102 |via=Google Books |access-date=25 September 2014|last1=Kapusta |first1=J. |last2=Müller |first2=B. |last3=Rafelski |first3=J. |date=9 December 2003 }} </ref> is a [[Physics:Subatomic particle|subatomic particle]], a [[Physics:Flavour (particle physics)|flavor]]-neutral [[Physics:Meson|meson]] consisting of a [[Physics:Charm quark|charm quark]] and a charm [[Physics:Antiparticle|antiquark]]. Mesons formed by a [[Physics:Bound state|bound state]] of a charm quark and a charm anti-quark are generally known as "charmonium". The {{SubatomicParticle|J/Psi}} is the most common form of charmonium, due to its [[Physics:Spin|spin]] of 1 and its low [[Physics:Rest mass|rest mass]]. The {{SubatomicParticle|J/Psi}} has a rest mass of {{val|3.0969|ul=GeV/c2}}, just above that of the {{SubatomicParticle|charmed eta}} ({{val|2.9836|ul=GeV/c2}}), and a mean lifetime of {{val|7.2|e=-21|ul=s}}. This lifetime was about a thousand times longer than expected.<ref>
{{cite press
 |date=18 October 1976 |title=Shared Physics prize for elementary particle
 |url=https://www.nobelprize.org/nobel_prizes/physics/laureates/1976/press.html
 |publisher=The Royal Swedish Academy of Sciences
 |access-date=2012-04-23 |df=dmy-all
}}</ref>}}
{{term|term= '''[[Joule]]'''}}{{defn|defn=The SI unit of energy.The joule, (symbol: J), is a [[SI derived unit|derived unit]] of [[Physics:Energy|energy]] in the [[International System of Units]].<ref>{{SIbrochure8th|page=120}}</ref> It is equal to the energy transferred to (or [[Physics:Work|work]] done on) an object when a [[Physics:Force|force]] of one [[Newton (unit)|newton]] acts on that object in the direction of the force's motion through a distance of one [[Metre|metre]] (1 newton metre or N⋅m). It is also the energy dissipated as heat when an electric [[Physics:Current (electricity)|current]] of one [[Ampere|ampere]] passes through a [[Physics:Electrical resistance and conductance|resistance]] of one [[Ohm|ohm]] for one second. It is named after the English physicist [[Biography:James Prescott Joule|James Prescott Joule]] (1818–1889).<ref>[https://web.archive.org/web/20060413141420/http://education.yahoo.com/reference/dictionary/entry/joule American Heritage Dictionary of the English Language], Online Edition (2009). Houghton Mifflin Co., hosted by [https://web.archive.org/web/20010502171832/http://education.yahoo.com/ Yahoo! Education].</ref><ref>''The American Heritage Dictionary'', Second College Edition (1985). Boston: Houghton Mifflin Co., p. 691.</ref><ref>''McGraw-Hill Dictionary of Physics'', Fifth Edition (1997). McGraw-Hill, Inc., p. 224.</ref> gh a conductor produces [[Physics:Heat|heat]].}}

{{term|term= '''[[Physics:Joule heating|Joule heating]]'''}}{{defn|defn=Also known as resistive, resistance, or Ohmic heating, is the process by which the passage of an [[Physics:Electric current|electric current]] through a conductor produces [[Physics:Heat|heat]].}}
{{glossary end}}

==K==
{{glossary}}
{{term|term= '''[[Kalman filter]]'''}}{{defn|defn=In statistics and control theory, Kalman filtering, also known as linear quadratic estimation (LQE), is an algorithm that uses a series of measurements observed over time, containing statistical noise and other inaccuracies, and produces estimates of unknown variables that tend to be more accurate than those based on a single measurement alone, by estimating a joint probability distribution over the variables for each timeframe. The Kalman filter has numerous applications in technology.}} 
{{term|term= '''[[Kelvin]]'''}}{{defn|defn=Is an [[Absolute scale|absolute]] [[Physics:Thermodynamic temperature|thermodynamic temperature]] [[Physics:Scale of temperature|scale]] using as its null point [[Physics:Absolute zero|absolute zero]], the temperature at which all [[Physics:Kinetic theory of gases|thermal motion]] ceases in the classical description of [[Physics:Thermodynamics|thermodynamics]]. The kelvin (symbol: K) is the [[SI base unit|base unit]] of [[Physics:Temperature|temperature]] in the [[International System of Units]] (SI).}} 
{{term|term= '''[[Physics:Kelvin–Planck statement|Kelvin–Planck statement]]'''}}{{defn|defn=(Or the ''Heat Engine Statement''), of the [[Physics:Second law of thermodynamics|second law of thermodynamics]] states that ''it is impossible to devise a [[Physics:Thermodynamic cycle|cyclically]] operating heat engine, the effect of which is to absorb [[Physics:Energy|energy]] in the form of heat from a single thermal reservoir and to deliver an equivalent amount of [[Physics:Work|work]]''.<ref name="Rao">{{cite book|last=Rao|first=Y. V. C.|title=Chemical Engineering Thermodynamics|publisher=Universities Press|isbn=978-81-7371-048-3|page=158|year=1997}}</ref>
This implies that it is impossible to build a [[Physics:Heat engine|heat engine]] that has 100% [[Physics:Thermal efficiency|thermal efficiency]].<ref name="Young&Freedman">{{cite book|last1=Young|first1=Hugh D.|last2=Freedman|first2=Roger A.|title=University Physics|edition=12|volume=1|year=2008|publisher=Pearson Education|isbn=978-0-321-50125-7}}</ref>}}
{{term|term= '''[[Physics:Kinematics|Kinematics]]'''}}{{defn|defn=Is a branch of [[Physics:Classical mechanics|classical mechanics]] that describes the [[Physics:Motion|motion]] of points, bodies (objects), and systems of bodies (groups of objects) without considering the forces that caused the motion.<ref name="Whittaker">{{cite book |title=A Treatise on the Analytical Dynamics of Particles and Rigid Bodies |author=Edmund Taylor Whittaker |at=Chapter 1 |year=1904 |publisher=Cambridge University Press |isbn=0-521-35883-3}}</ref><ref name=Beggs>{{cite book |title=Kinematics |author=Joseph Stiles Beggs |page=1 |url=https://books.google.com/books?id=y6iJ1NIYSmgC |isbn=0-89116-355-7 |year=1983 |publisher=Taylor & Francis}}</ref><ref name=Wright>{{cite book |title=Elements of Mechanics Including Kinematics, Kinetics and Statics|author=Thomas Wallace Wright |url=https://books.google.com/books?id=-LwLAAAAYAAJ |at=Chapter 1 |year=1896 |publisher=E and FN Spon}}</ref>}}
{{glossary end}}

==L==
{{glossary}}

{{term|term= '''[[Physics:Laminar flow|Laminar flow]]'''}}{{defn|defn=In [[Physics:Fluid dynamics|fluid dynamics]], laminar flow is characterized by fluid particles following smooth paths in layers, with each layer moving smoothly past the adjacent layers with little or no mixing.<ref>Streeter, V.L. (1951-1966) ''Fluid Mechanics'', Section 3.3 (4th edition). McGraw-Hill</ref> At low velocities, the fluid tends to flow without lateral mixing, and adjacent layers slide past one another like playing cards. There are no cross-currents perpendicular to the direction of flow, nor eddies or swirls of fluids.<ref name="Geankoplis, Christie John 2003">{{cite book
 |title = Transport Processes and Separation Process Principles
 |last = Geankoplis
 |first = Christie John
 |year = 2003
 |publisher = Prentice Hall Professional Technical Reference
 |isbn = 978-0-13-101367-4
 |url = http://www.pearsonhighered.com/educator/product/Transport-Processes-and-Separation-Process-Principles-Includes-Unit-Operations/9780131013674.page
 |url-status = live
 |archive-url = https://web.archive.org/web/20150501122109/http://www.pearsonhighered.com/educator/product/Transport-Processes-and-Separation-Process-Principles-Includes-Unit-Operations/9780131013674.page
 |archive-date = 2015-05-01
}}</ref> In laminar flow, the motion of the particles of the fluid is very orderly with particles close to a solid surface moving in straight lines parallel to that surface.<ref>{{cite web
 |url = http://www.efm.leeds.ac.uk/CIVE/CIVE1400/Section4/laminar_turbulent.htm
 |title = Real Fluids
 |last1 = Noakes
 |first1 = Cath
 |last2 = Sleigh
 |first2 = Andrew
 |date = January 2009
 |work = An Introduction to Fluid Mechanics
 |publisher = University of Leeds
 |access-date = 23 November 2010
 |url-status = dead
 |archive-url = https://web.archive.org/web/20101021003853/http://www.efm.leeds.ac.uk/CIVE/CIVE1400/Section4/laminar_turbulent.htm
 |archive-date = 21 October 2010
}}</ref>
Laminar flow is a flow regime characterized by high [[Physics:Momentum diffusion|momentum diffusion]] and low momentum [[Astronomy:Convection|convection]].}}
{{term|term= '''[[Laplace transform]]'''}}{{defn|defn=In [[Mathematics|mathematics]], the Laplace transform, named after its inventor [[Biography:Pierre-Simon Laplace|Pierre-Simon Laplace]] ({{IPAc-en|l|ə|ˈ|p|l|ɑ:|s}}), is an [[Integral transform|integral transform]] that converts a function of a real variable <math>t</math> (often time) to a function of a [[Complex analysis|complex variable]] <math>s</math> (complex frequency). The transform has many applications in science and engineering because it is a tool for solving [[Differential equation|differential equation]]s. In particular, it transforms differential equations into algebraic equations and [[Convolution|convolution]] into multiplication.<ref>{{Cite web|title=Laplace Transform: A First Introduction|url=https://mathvault.ca/laplace-transform/|access-date=2020-08-08|website=Math Vault}}</ref><ref>{{Cite web|title=Differential Equations - Laplace Transforms|url=https://tutorial.math.lamar.edu/classes/de/LaplaceIntro.aspx|access-date=2020-08-08|website=tutorial.math.lamar.edu}}</ref><ref>{{Cite web|last=Weisstein|first=Eric W.|title=Laplace Transform|url=https://mathworld.wolfram.com/LaplaceTransform.html|access-date=2020-08-08|website=mathworld.wolfram.com}}</ref>}}
{{term|term= '''[[Engineering:LC circuit|LC circuit]]'''}}{{defn|defn=A circuit consisting entirely of inductors (L) and capacitors (C).}} 
{{term|term= '''[[Biology:Le Chatelier's principle|Le Chatelier's principle]]'''}}{{defn|defn=Le Chatelier's principle, also called ''Chatelier's principle'', is a principle of [[Chemistry:Chemistry|chemistry]] used to predict the effect of a change in conditions on [[Chemistry:Chemical equilibrium|chemical equilibria]]. The principle is named after French chemist Henry Louis Le Chatelier, and sometimes also credited to [[Biography:Karl Ferdinand Braun|Karl Ferdinand Braun]], who discovered it independently. It can be stated as:

{{quote|When any system at equilibrium for a long period of time is subjected to a change in [[Chemistry:Concentration|concentration]], [[Physics:Temperature|temperature]], [[Physics:Volume|volume]], or [[Physics:Pressure|pressure]], (1) the system changes to a new equilibrium, and (2) this change partly counteracts the applied change.}}

It is common to treat the principle as a more general observation of [[Philosophy:System|system]]s,<ref name="Systemantics">{{cite book| quote = The System always kicks back| first = John| last = Gall| title = The Systems Bible| edition = 3rd| publisher = General Systemantics Press| year = 2002}}</ref> such as

{{quote|When a settled system is disturbed, it will adjust to diminish the change that has been made to it|author=|title=|source=}}

or, "roughly stated",<ref name="Systemantics"/>

{{quote|Any change in [[Philosophy:Status quo|status quo]] prompts an opposing reaction in the responding system.}}}}
{{term|term= '''[[Physics:Lenz's law|Lenz's law]]'''}}{{defn|defn=Lenz's law, named after the physicist [[Biography:Emil Lenz|Emil Lenz]] who formulated it in 1834,<ref>Lenz, E. (1834), "[http://gallica.bnf.fr/ark:/12148/bpt6k151161/f499.image.r=lenz.langEN Ueber<!--[sic]--> die Bestimmung der Richtung der durch elektodynamische Vertheilung erregten galvanischen Ströme]", ''Annalen der Physik und Chemie'', '''107''' (31), pp. 483–494. A partial translation of the paper is available in  Magie, W. M. (1963), ''A Source Book in Physics'', Harvard: Cambridge MA, pp. 511–513.</ref> states that the direction of the [[Physics:Electric current|electric current]] which is [[Physics:Electromagnetic induction|induced]] in a [[Physics:Electrical conductor|conductor]] by a changing [[Physics:Magnetic field|magnetic field]] is such that the magnetic field created by the induced current opposes the initial changing magnetic field.

It is a [[Scientific law|qualitative law]] that specifies the direction of induced current, but states nothing about its magnitude. Lenz's law explains the direction of many effects in [[Physics:Electromagnetism|electromagnetism]], such as the direction of voltage induced in an [[Engineering:Inductor|inductor]] or [[Engineering:Electromagnetic coil|wire loop]] by a changing current, or the drag force of [[Physics:Eddy current|eddy current]]s exerted on moving objects in a magnetic field.

Lenz's law may be seen as analogous to [[Physics:Newton's laws of motion#Newton's third law|Newton's third law]] in [[Physics:Classical mechanics|classical mechanics]].<ref name="Electromagnetics explained:
a handbook for wireless/RF, EMC, and high-speed electronics">Schmitt, Ron. [https://archive.org/details/electromagnetics0000schm/page/75 <!-- quote="lenz's law" "newton's third law". --> ''Electromagnetics explained'']. 2002. Retrieved 16 July 2010.</ref>}} 
{{term|term= '''[[Physics:Lepton|Lepton]]'''}}{{defn|defn=In [[Physics:Particle physics|particle physics]], a lepton is an [[Physics:Elementary particle|elementary particle]] of half-integer spin ([[Physics:Spin|spin]] {{Frac|1|2}}) that does not undergo [[Physics:Strong interaction|strong interaction]]s.<ref>
{{cite encyclopedia
 |title=Lepton (physics)
 |url=http://www.britannica.com/EBchecked/topic/336940/lepton
 |encyclopedia=[[Encyclopædia Britannica]]
 |access-date=2010-09-29
}}</ref> Two main classes of leptons exist: [[Physics:Electric charge|charged]] leptons (also known as the [[Physics:Electron|electron]]-like leptons), and neutral leptons (better known as [[Physics:Neutrino|neutrino]]s). Charged leptons can combine with other particles to form various composite particles such as [[Physics:Atom|atom]]s and [[Physics:Positronium|positronium]], while neutrinos rarely interact with anything, and are consequently rarely observed. The best known of all leptons is the [[Physics:Electron|electron]].}}
{{term|term= '''[[Engineering:Lever|Lever]]'''}}{{defn|defn=Is a [[Engineering:Simple machine|simple machine]] consisting of a [[Physics:Beam (structure)|beam]] or rigid rod pivoted at a fixed [[Engineering:Hinge|hinge]], or ''fulcrum''. A lever is a rigid body capable of rotating on a point on itself. On the basis of the locations of fulcrum, load and effort, the lever is divided into [[Engineering:Lever#Classes of levers|three types]]. Also, leverage is mechanical advantage gained in a system. It is one of the six [[Engineering:Simple machine|simple machine]]s identified by Renaissance scientists. A lever amplifies an input force to provide a greater output force, which is said to provide ''leverage''. The ratio of the output force to the input force is the [[Physics:Mechanical advantage|mechanical advantage]] of the lever. As such, the lever is a [[Physics:Mechanical advantage device|mechanical advantage device]], trading off force against movement.}}
{{term|term= '''[[L'Hôpital's rule]]'''}}{{defn|defn=In [[Mathematics|mathematics]], more specifically [[Calculus|calculus]], L'Hôpital's rule or L'Hospital's rule ({{IPA-fr|lopital|lang}}, 
{{IPAc-en|lang|ˌ|l|oʊ|p|iː|ˈ|t|ɑː|l}}, {{respell|loh-pee|TAHL}}) provides a technique to evaluate [[Limit of a function|limits]] of [[Indeterminate form|indeterminate form]]s. Application (or repeated application) of the rule often converts an indeterminate form to an expression that can be easily evaluated by substitution. The rule is named after the 17th-century {{wipe|France}} [[Biography:Mathematician|mathematician]] [[Biography:Guillaume de l'Hôpital|Guillaume de l'Hôpital]]. Although the rule is often attributed to L'Hôpital, the theorem was first introduced to him in 1694 by the Swiss mathematician [[Biography:Johann Bernoulli|Johann Bernoulli]].

L'Hôpital's rule states that for functions {{mvar|f}} and {{mvar|g}} which are [[Differentiable function|differentiable]] on an open [[Interval (mathematics)|interval]] {{mvar|I}} except possibly at a point {{mvar|c}} contained in {{mvar|I}}, if <math>\lim_{x\to c}f(x)=\lim_{x\to c}g(x)=0 \text{ or } \pm\infty,</math> and <math>g'(x)\ne 0</math> for all {{mvar|x}} in {{mvar|I}} with {{math|1=''x'' ≠ ''c''}}, and <math>\lim_{x\to c}\frac{f'(x)}{g'(x)}</math> exists, then
:<math>\lim_{x\to c}\frac{f(x)}{g(x)} = \lim_{x\to c}\frac{f'(x)}{g'(x)}.</math>

The differentiation of the numerator and denominator often simplifies the quotient or converts it to a limit that can be evaluated directly.}}
{{term|term= '''[[Physics:Light|Light]]'''}}{{defn|defn=Light or ''visible light'' is [[Physics:Electromagnetic radiation|electromagnetic radiation]] within the portion of the [[Physics:Electromagnetic spectrum|electromagnetic spectrum]] that can be [[Philosophy:Visual perception|perceived]] by the [[Biology:Human eye|human eye]].<ref>CIE (1987). [http://www.cie.co.at/publ/abst/17-4-89.html ''International Lighting Vocabulary''] {{Webarchive|url=https://web.archive.org/web/20100227034508/http://www.cie.co.at/publ/abst/17-4-89.html |date=27 February 2010 }}. Number 17.4. CIE, 4th edition. {{ISBN|978-3-900734-07-7}}.<br/>By the ''International Lighting Vocabulary'', the definition of ''light'' is: "Any radiation capable of causing a visual sensation directly."</ref> Visible light is usually defined as having [[Wavelength|wavelength]]s in the range of 400–700 [[Nanometre|nm]], between the [[Physics:Infrared|infrared]] (with longer wavelengths) and the [[Physics:Ultraviolet|ultraviolet]] (with shorter wavelengths).<ref name="Pal2001">{{cite book |last1=Pal |first1=G.K. |last2=Pal |first2=Pravati |title=Textbook of Practical Physiology |chapter-url=https://books.google.com/books?id=CcJvIiesqp8C&pg=PA387 |access-date=11 October 2013 |edition=1st |year=2001 |publisher=Orient Blackswan |location=Chennai |isbn=978-81-250-2021-9 |page=387 |chapter=chapter 52 |quote=The human eye has the ability to respond to all the wavelengths of light from 400–700 nm. This is called the visible part of the spectrum.}}</ref><ref name="BuserImbert1992">{{cite book |last1=Buser |first1=Pierre A. |last2=Imbert |first2=Michel |title=Vision |url=https://archive.org/details/vision0000buse |url-access=registration |access-date=11 October 2013 |year=1992 |publisher=MIT Press |isbn=978-0-262-02336-8 |page=[https://archive.org/details/vision0000buse/page/50 50] |quote=Light is a special class of radiant energy embracing wavelengths between 400 and 700 nm (or mμ), or 4000 to 7000 Å.}}</ref> This wavelength means a [[Physics:Frequency|frequency]] range of roughly 430–750 [[Terahertz (unit)|terahertz]] (THz).}}
{{term|term= '''[[Physics:Linear actuator|Linear actuator]]'''}}{{defn|defn=Is an [[Engineering:Actuator|actuator]] that creates motion in a straight line, in contrast to the circular motion of a conventional [[Physics:Electric motor|electric motor]]. Linear actuators are used in machine tools and industrial machinery, in computer [[Engineering:Peripheral|peripheral]]s such as disk drives and printers, in [[Engineering:Valve|valve]]s and [[Engineering:Damper (flow)|dampers]], and in many other places where linear  motion is required. [[Physics:Hydraulics|Hydraulic]] or [[Engineering:Pneumatics|pneumatic]] cylinders inherently produce linear motion. Many other mechanisms are used to generate linear motion from a rotating motor. }} 
{{term|term= '''[[Linear algebra]]'''}}{{defn|defn=The mathematics of equations where the unknowns are only in the first power. }} 
{{term|term= '''[[Physics:Linear elasticity|Linear elasticity]]'''}}{{defn|defn=Is a mathematical model of how solid objects deform and become internally stressed due to prescribed loading conditions. It is a simplification of the more general [[Physics:Finite strain theory|nonlinear theory of elasticity]] and a branch of [[Physics:Continuum mechanics|continuum mechanics]].}}
{{term|term= '''[[Physics:Liquid|Liquid]]'''}}{{defn|defn=A liquid is a nearly [[Physics:Compressibility|incompressible]] [[Physics:Fluid|fluid]] that conforms to the shape of its container but retains a (nearly) constant volume independent of pressure. As such, it is one of [[Physics:State of matter#Four fundamental states|the four fundamental states of matter]] (the others being [[Physics:Solid|solid]], [[Physics:Gas|gas]], and [[Physics:Plasma|plasma]]), and is the only state with a definite volume but no fixed shape. A liquid is made up of tiny vibrating particles of matter, such as atoms, held together by intermolecular bonds. Like a gas, a liquid is [[Physics:Fluid|able to flow]] and take the shape of a container. Most liquids resist compression, although others can be compressed. Unlike a gas, a liquid does not disperse to fill every space of a container, and maintains a fairly constant density. A distinctive property of the liquid state is [[Physics:Surface tension|surface tension]], leading to [[Physics:Wetting|wetting]] phenomena. [[Chemistry:Water|Water]] is, by far, the most common liquid on Earth.}}
{{term|term= '''[[Logarithm]]'''}}{{defn|defn=In [[Mathematics|mathematics]], the logarithm is the [[Inverse function|inverse function]] to [[Exponentiation|exponentiation]]. That means the logarithm of a given number&nbsp;{{mvar|x}} is the exponent to which another fixed number, the ''[[Base (exponentiation)|base]]''&nbsp;{{mvar|b}}, must be raised, to produce that number&nbsp;{{mvar|x}}. In the simplest case, the logarithm counts the number of occurrences of the same factor in repeated multiplication; e.g., since {{math|1000 {{=}} 10 × 10 × 10 {{=}} 10<sup>3</sup>}}, the "logarithm base {{math|10}}" of {{math|1000}} is {{math|3}}, or {{math|log<sub>10</sub>(1000) {{=}} 3}}. The logarithm of {{mvar|x}} to ''base'' {{mvar|b}} is denoted as {{math|log<sub>''b''</sub>(''x'')}}, or without parentheses, {{math|log<sub>''b''</sub>&thinsp;''x''}}, or even without the explicit base, {{math|log&thinsp;''x''}}, when no confusion is possible, or when the base does not matter such as in [[Big O notation|big O notation]].

More generally, exponentiation allows any positive [[Real number|real number]] as base to be raised to any real power, always producing a positive result, so {{math|log<sub>''b''</sub>(''x'')}} for any two positive real numbers&nbsp;{{mvar|b}} and&nbsp;{{mvar|x}}, where&nbsp;{{mvar|b}} is not equal to&nbsp;{{math|1}}, is always a unique real number&nbsp;{{mvar|y}}. More explicitly, the defining relation between exponentiation and logarithm is:

:<math> \log_b(x) = y \ </math> exactly if <math>\ b^y = x\ </math> and <math>\ x > 0</math> and <math>\ b > 0</math> and <math>\ b \ne 1</math>.

For example, {{math|1=log<sub>2</sub>&thinsp;64 = 6}}, as {{math|1=2<sup>6</sup> = 64}}.

The logarithm base {{math|10}} (that is {{math|1=''b'' = 10}}) is called the decimal or [[Common logarithm|common logarithm]] and is commonly used in science and engineering. The [[Natural logarithm|natural logarithm]] has the [[E (mathematical constant)|number {{mvar|e}}]]&nbsp;(that is {{math|''b'' ≈ 2.718}}) as its base; its use is widespread in mathematics and [[Physics:Physics|physics]], because of its simpler [[Integral|integral]] and [[Derivative|derivative]]. The [[Binary logarithm|binary logarithm]] uses base {{math|2}} (that is {{math|1=''b'' = 2}}) and is frequently used in [[Computer science|computer science]]. Logarithms are examples of [[Concave function|concave function]]s.<ref>{{citation|url=https://mathvault.ca/logarithm-theory/|title=The Ultimate Guide to Logarithm — Theory & Applications|date=8 May 2016|website=Math Vault|access-date=24 July 2019}}</ref>}}
{{term|term= '''[[Identity (mathematics)#Logarithmic identities|Logarithmic identities]]'''}}{{defn|defn=Several important formulas, sometimes called logarithmic identities or ''log laws'', relate logarithms to one another.<ref>All statements in this section can be found in {{harvnb|Shirali|2002|p=|loc=Section 4}}, {{harvnb|Downing|2003|p=275}}, or {{harvnb|Kate|Bhapkar|2009|p=1-1}}, for example.</ref>}}
{{term|term= '''[[Physics:Logarithmic mean temperature difference|Logarithmic mean temperature difference]]'''}}{{defn|defn=(Also known as log mean temperature difference, LMTD) is used to determine the temperature driving force for [[Physics:Heat transfer|heat transfer]] in flow systems, most notably in [[Physics:Heat exchanger|heat exchanger]]s. The LMTD is a logarithmic average of the temperature difference between the hot and cold feeds at each end of the double pipe exchanger. For a given heat exchanger with constant area and heat transfer coefficient, the larger the LMTD, the more heat is transferred. The use of the LMTD arises straightforwardly from the analysis of a heat exchanger with constant flow rate and fluid thermal properties.}}
{{term|term= '''[[Physics:Lumped element model#Thermal systems|Lumped capacitance model]]'''}}{{defn|defn=A lumped-capacitance model, also called ''lumped system analysis'',<ref>{{cite book | last = Incropera |author2=DeWitt |author3=Bergman |author4=Lavine | title = Fundamentals of Heat and Mass Transfer | url = https://archive.org/details/fundamentalsheat00incr_869 | url-access = limited | edition = 6th | year = 2007 | isbn = 978-0-471-45728-2 | publisher = John Wiley & Sons | pages = [https://archive.org/details/fundamentalsheat00incr_869/page/n267 260]–261}}</ref> reduces a thermal system to a number of discrete “lumps” and assumes that the [[Physics:Temperature|temperature]] difference inside each lump is negligible. This approximation is useful to simplify otherwise complex [[Differential equation|differential]] heat equations. It was developed as a mathematical analog of electrical capacitance, although it also includes thermal analogs of [[Physics:Electrical resistance|electrical resistance]] as well.}}
{{term|term= '''[[Physics:Lumped element model|Lumped element model]]'''}}{{defn|defn=The lumped-element model (also called ''lumped-parameter model'', or ''lumped-component model'') simplifies the description of the behaviour of spatially distributed physical systems into a [[Engineering:Topology (electrical circuits)|topology]] consisting of discrete entities that approximate the behaviour of the distributed system under certain assumptions. It is useful in [[Physics:Electrical network|electrical systems]] (including [[Engineering:Electronics|electronics]]), mechanical [[Physics:Multibody system|multibody system]]s, [[Physics:Heat transfer|heat transfer]], [[Physics:Acoustics|acoustics]], etc. Mathematically speaking, the simplification reduces the state space of the system to a finite [[Physics:Dimension|dimension]], and the [[Partial differential equation|partial differential equation]]s (PDEs) of the continuous (infinite-dimensional) time and space model of the physical system into [[Ordinary differential equation|ordinary differential equation]]s (ODEs) with a finite number of parameters.}}
{{glossary end}}

==M==
{{glossary}}
{{term|term= '''[[Macaulay's method]]'''}}{{defn|defn='''(The double integration method)''' is a technique used in [[Structural analysis|structural analysis]] to determine the [[Engineering:Deflection (engineering)|deflection]] of Euler-Bernoulli beams. Use of Macaulay’s technique is very convenient for cases of discontinuous and/or discrete loading. Typically partial uniformly distributed loads (u.d.l.) and uniformly varying loads (u.v.l.) over the span and a number of concentrated loads are conveniently handled using this technique.}}
{{term|term= '''[[Physics:Mach number|Mach number]]'''}}{{defn|defn=The ratio of the speed of an object to the speed of sound.}} 
{{term|term= '''Machine'''}}{{defn|defn=A machine (or mechanical device) is a mechanical structure that uses [[Physics:Power|power]] to apply [[Physics:Force|force]]s and control [[Physics:Motion|movement]] to perform an intended action. Machines can be driven by animals and people, by natural forces such as wind and water, and by [[Chemistry:Chemical energy|chemical]], [[Physics:Thermal energy|thermal]], or [[Physics:Electricity|electrical]] power, and include a system of [[Engineering:Mechanism (engineering)|mechanisms]] that shape the actuator input to achieve a specific application of output forces and movement. They can also include computers and sensors that monitor performance and plan movement, often called [[Engineering:Mechanical system|mechanical system]]s.}}
{{term|term= '''[[Machine code]]'''}}{{defn|defn=In [[Computer programming|computer programming]], machine code, consisting of machine language instructions, is a [[Low-level programming language|low-level programming language]] used to directly control a computer's [[Central processing unit|central processing unit]] (CPU). Each instruction causes the CPU to perform a very specific task, such as a load, a store, a jump, or an [[Arithmetic logic unit|arithmetic logic unit]] (ALU) operation on one or more units of data in the CPU's [[Processor register|register]]s or [[CPU cache|memory]].}}
{{term|term= '''[[Engineering:Machine element|Machine element]]'''}}{{defn|defn=Or ''hardware'', refers to an elementary component of a machine.  These elements consist of three basic types:
# ''[[Structural element|structural components]]'' such as frame members, [[Physics:Bearing (mechanical)|bearings]], [[Engineering:Axle|axles]], [[Engineering:Spline (mechanical)|splines]], [[Engineering:Fastener|fastener]]s, seals, and [[Physics:Lubricant|lubricant]]s, 
# ''[[Engineering:Mechanism (engineering)|mechanisms]]'' that [[Motion control|control movement]] in various ways such as [[Engineering:Gear train|gear train]]s, [[Engineering:Belt (mechanical)|belt]] or [[Physics:Chain drive|chain drive]]s, [[Engineering:Linkage (mechanical)|linkages]], [[Engineering:Cam|cam]] and [[Engineering:Cam follower|follower]] systems, including [[Engineering:Brake|brake]]s and [[Engineering:Clutch|clutch]]es, and 
# ''[[Control system|control components]]'' such as buttons, switches, indicators, sensors, actuators and computer controllers.<ref>Robert L. Norton, '''Machine Design,''' (4th Edition), Prentice-Hall, 2010</ref>  

While generally not considered to be a machine element, the shape, texture and color of covers are an important part of a machine that provide a [[Social:Industrial design|styling and operational interface]] between the mechanical components of a machine and its users.

Machine elements are basic mechanical parts and features used as the building blocks of most machines.<ref>{{Citation | last = Matthews | first = Clifford | last2 = [[Organization:American Society of Mechanical Engineers|American Society of Mechanical Engineers]] | title = ASME engineer's data book | page = 249 | publisher = ASME Press | year = 2005 | edition = 2nd | url = https://books.google.com/books?id=dPS2KU0gj-8C&pg=PA249 | isbn = 978-0-7918-0229-8 | postscript =.}}</ref> Most are [[Technical standard|standardized]] to common sizes, but customs are also common for specialized applications.<ref name="bhandari">{{Citation | last = Bhandari | first = V. B. | title = Design of machine elements | page = 10 | publisher = Tata McGraw-Hill | year = 2007 | edition = 2nd | url = https://books.google.com/books?id=d-eNe-VRc1oC&pg=PA10 | isbn = 978-0-07-061141-2 | postscript =.}}</ref> }}
{{term|term= '''[[Machine learning]]'''}}{{defn|defn=(ML), is the study of computer [[Algorithm|algorithm]]s that improve automatically through experience and by the use of data.<ref>{{Cite book|last=Mitchell|first=Tom|url=http://www.cs.cmu.edu/~tom/mlbook.html|title=Machine Learning|publisher=McGraw Hill|year=1997|isbn=0-07-042807-7|location=New York|oclc=36417892|author-link=Tom M. Mitchell}}</ref> It is seen as a part of [[Artificial intelligence|artificial intelligence]]. Machine learning algorithms build a model based on sample data, known as "training data", in order to make predictions or decisions without being explicitly programmed to do so.{{refn|The definition "without being explicitly programmed" is often attributed to [[Biography:Arthur Samuel|Arthur Samuel]], who coined the term "machine learning" in 1959, but the phrase is not found verbatim in this publication, and may be a paraphrase that appeared later. Confer "Paraphrasing Arthur Samuel (1959), the question is: How can computers learn to solve problems without being explicitly programmed?" in {{Cite conference|title=Automated Design of Both the Topology and Sizing of Analog Electrical Circuits Using Genetic Programming|conference=Artificial Intelligence in Design '96|last1=Koza|first1=John R.|last2=Bennett|first2=Forrest H.|last3=Andre|first3=David|last4=Keane|first4=Martin A.|date=1996|publisher=Springer, Dordrecht|pages=151–170|language=en|doi=10.1007/978-94-009-0279-4_9}}}} Machine learning algorithms are used in a wide variety of applications, such as in medicine, [[Email filtering|email filtering]], [[Speech recognition|speech recognition]], and [[Computer vision|computer vision]], where it is difficult or unfeasible to develop conventional algorithms to perform the needed tasks.<ref name="tvt">Hu, J.; Niu, H.; Carrasco, J.; Lennox, B.; Arvin, F., "[https://ieeexplore.ieee.org/document/9244647 Voronoi-Based Multi-Robot Autonomous Exploration in Unknown Environments via Deep Reinforcement Learning]" IEEE Transactions on Vehicular Technology, 2020.</ref>}}
{{term|term= '''[[Maclaurin series]]'''}}{{defn|defn=In [[Mathematics|mathematics]], the '''Taylor series''' of a [[Function (mathematics)|function]] is an [[Series (mathematics)|infinite sum]] of terms that are expressed in terms of the function's [[Derivative|derivative]]s at a single point. For most common functions, the function and the sum of its Taylor series are equal near this point. Taylor's series are named after [[Biography:Brook Taylor|Brook Taylor]],  who introduced them in 1715.  If zero is the point where the derivatives are considered, a Taylor series is also called a Maclaurin series, after Colin Maclaurin, who made extensive use of this special case of Taylor series in the 18th century.}}
{{term|term= '''[[Physics:Magnetic field|Magnetic field]]'''}}{{defn|defn=A magnetic field is a [[Vector field|vector field]] that describes the magnetic influence on moving [[Physics:Electric charge|electric charge]]s, electric currents,<ref>{{cite book|last1=Feynman|first1=Richard P.|url=https://www.feynmanlectures.caltech.edu/|title=The Feynman Lectures on Physics|last2=Leighton|first2=Robert B.|last3=Sands|first3=Matthew|date=1963|publisher=California Institute of Technology|isbn=9780465040858|volume=2}}</ref>{{Rp|ch1}}<ref>{{cite book |last1 = Young |first1 = Hugh D. |last2 = Freedman |first2 = Roger A. |last3 = Ford |first3 = A. Lewis |title = Sears and Zemansky's university physics : with modern physics |publisher = Pearson Addison-Wesley |volume = 2 |date = 2008 |pages = 918–919 |isbn = 9780321501219}}</ref> and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular to its own velocity and to the magnetic field.<ref name=":0" />{{Rp|ch13}}<ref>Purcell, Edward. p278. Electricity and Magnetism, 3rd edition, Cambridge University Press, 2013. 839pp.</ref>  A permanent magnet's magnetic field pulls on ferromagnetic materials such as [[Chemistry:Iron|iron]], and attracts or repels other magnets.  In addition, a magnetic field that varies with location will exert a force on a range of non-magnetic materials by affecting the motion of their outer atomic electrons. Magnetic fields surround magnetized materials, and are created by electric currents such as those used in [[Physics:Electromagnet|electromagnet]]s, and by [[Physics:Electric field|electric field]]s varying in time.  Since both strength and direction of a magnetic field may vary with location, they are described as a map assigning a vector to each point of space or, more precisely—because of the way the magnetic field transforms under mirror reflection—as a [[Physics:Field|field]] of [[Pseudovector|pseudovector]]s.

In electromagnetics, the term "magnetic field" is used for two distinct but closely related vector fields denoted by the symbols {{math|'''B'''}} and {{math|'''H'''}}. In the [[International System of Units]], {{math|'''H'''}}, magnetic field strength, is measured in the SI base units of [[Ampere|ampere]] per meter (A/m).<ref>{{SIbrochure9th}}, p. 22</ref> {{math|'''B'''}}, [[Physics:Magnetic flux|magnetic flux]] density, is measured in [[Tesla (unit)|tesla]] (in SI base units: kilogram per second<sup>2</sup> per ampere),<ref>{{SIbrochure9th}}, p. 21</ref> which is equivalent to [[Newton (unit)|newton]] per meter per ampere. {{math|'''H'''}} and {{math|'''B'''}} differ in how they account for magnetization. In a [[Physics:Vacuum|vacuum]], the two fields are related through the [[Physics:Vacuum permeability|vacuum permeability]], <math>\mathbf{B}/\mu_0 = \mathbf{H}</math>; but in a magnetized material, the terms differ by the material's [[Physics:Magnetization|magnetization]] at each point.}}
{{term|term= '''[[Physics:Magnetism|Magnetism]]'''}}{{defn|defn=Is a class of physical attributes that are mediated by [[Physics:Magnetic field|magnetic field]]s. [[Physics:Electric current|Electric current]]s and the [[Physics:Magnetic moment|magnetic moment]]s of elementary particles give rise to a magnetic field, which acts on other currents and magnetic moments. Magnetism is one aspect of the combined phenomenon of [[Physics:Electromagnetism|electromagnetism]]. The most familiar effects occur in [[Physics:Ferromagnetic|ferromagnetic]] materials, which are strongly attracted by magnetic fields and can be [[Physics:Magnetization|magnetized]] to become permanent [[Physics:Magnet|magnet]]s, producing magnetic fields themselves.  Demagnetizing a magnet is also possible.  Only a few substances are ferromagnetic; the most common ones are [[Chemistry:Iron|iron]], [[Chemistry:Cobalt|cobalt]] and [[Chemistry:Nickel|nickel]] and their alloys. The rare-earth metals [[Chemistry:Neodymium|neodymium]] and [[Chemistry:Samarium|samarium]] are less common examples. The prefix ''{{linktext|ferro-}}'' refers to [[Chemistry:Iron|iron]], because permanent magnetism was first observed in [[Physics:Lodestone|lodestone]], a form of natural iron ore called [[Chemistry:Magnetite|magnetite]], Fe<sub>3</sub>O<sub>4</sub>.}}
{{term|term= '''[[Engineering:Manufacturing engineering|Manufacturing engineering]]'''}}{{defn|defn=Is a branch of professional [[Engineering:Engineering|engineering]] that shares many common concepts and ideas with other fields of engineering such as mechanical, chemical, electrical, and industrial engineering. 
Manufacturing engineering requires the ability to plan the practices of manufacturing; to research and to develop tools, processes, machines and equipment; and to integrate the facilities and systems for producing quality products with the optimum expenditure of capital.<ref>{{Cite book|doi = 10.1007/978-94-011-7038-3_1|title = Handbook of Electronics Manufacturing Engineering|pages = 1–4|year = 1986|last1 = Matisoff|first1 = Bernard S.|isbn = 978-94-011-7040-6|chapter = Manufacturing Engineering: Definition and Purpose}}</ref>

The manufacturing or production engineer's primary focus is to turn raw material into an updated or new product in the most effective, efficient & economic way possible.}}
{{term|term= '''[[Physics:Mass balance|Mass balance]]'''}}{{defn|defn=A mass balance, also called a ''material balance'', is an application of [[Physics:Conservation of mass|conservation of mass]] to the analysis of physical systems. By accounting for material entering and leaving a system, [[Physics:Mass flow|mass flow]]s can be identified which might have been unknown, or difficult to measure without this technique.  The exact [[Physics:Conservation law|conservation law]] used in the analysis of the system depends on the context of the problem, but all revolve around mass conservation, i.e., that [[Physics:Matter|matter]] cannot disappear or be created spontaneously.<ref name="himmelblau">{{cite book | last = Himmelblau | first = David M. | title = Basic Principles and Calculations in Chemical Engineering | edition = 2nd | date = 1967 | publisher = Prentice Hall | url = http://www.pearsonhighered.com/educator/product/Basic-Principles-and-Calculations-in-Chemical-Engineering/9780132346603.page}}</ref>{{rp|59–62}}}}
{{term|term= '''[[Physics:Mass density|Mass density]]'''}}{{defn|defn=The '''density''' (more precisely, the '''volumetric mass density'''; also known as '''specific mass'''), of a substance is its [[Physics:Mass|mass]] per unit [[Physics:Volume|volume]]. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' can also be used. Mathematically, density is defined as mass divided by volume:<ref>{{cite web | url =http://www.grc.nasa.gov/WWW/BGH/fluden.html | title =Gas Density Glenn research Center | author =''The National Aeronautic and Atmospheric Administration's'' ''[[Organization:Glenn Research Center|Glenn Research Center]]'' | publisher =grc.nasa.gov | url-status =dead | archive-url =https://web.archive.org/web/20130414132531/http://www.grc.nasa.gov/WWW/BGH/fluden.html | archive-date =April 14, 2013 | df =mdy-all | access-date =April 9, 2013 }}</ref> 

:<math> \rho = \frac{m}{V}</math>

where ''ρ'' is the density, ''m'' is the mass, and ''V'' is the volume. In some cases (for instance, in the United States oil and gas industry), density is loosely defined as its [[Physics:Weight|weight]] per unit [[Physics:Volume|volume]],<ref>{{cite web|url=http://oilgasglossary.com/density.html |title=Density definition in Oil Gas Glossary |publisher=Oilgasglossary.com |access-date=September 14, 2010 |url-status=dead |archive-url=https://web.archive.org/web/20100805010226/http://oilgasglossary.com/density.html |archive-date=August 5, 2010 }}</ref> although this is scientifically inaccurate – this quantity is more specifically called [[Physics:Specific weight|specific weight]].}}
{{term|term= '''Mass moment of inertia'''}}{{defn|defn=The '''moment of inertia''', otherwise known as the '''mass moment of inertia''', '''angular mass''', '''second moment of mass''', or most accurately, '''rotational inertia''', of a [[Rigid body|rigid body]] is a quantity that determines the [[Physics:Torque|torque]] needed for a desired [[Physics:Angular acceleration|angular acceleration]] about a rotational axis, akin to how [[Physics:Mass|mass]] determines the [[Physics:Force|force]] needed for a desired [[Physics:Acceleration|acceleration]]. It depends on the body's mass distribution and the axis chosen, with larger moments requiring more torque to change the body's rate of rotation.}}
{{term|term= '''[[Chemistry:Mass number|Mass number]]'''}}{{defn|defn=The mass number (symbol ''A'', from the German word ''Atomgewicht'' [atomic weight]),<ref>Jensen, William B. (2005). The Origins of the Symbols A and Z for Atomic Weight and Number. ''J. Chem. Educ.'' 82: 1764. [http://www.che.uc.edu/jensen/W.%20B.%20Jensen/Reprints/123.%20A%20&%20Z.pdf link].</ref> also called  '''atomic mass number''' or '''nucleon number''', is the total number of [[Physics:Proton|proton]]s and [[Physics:Neutron|neutron]]s (together known as [[Physics:Nucleon|nucleon]]s) in an [[Physics:Atomic nucleus|atomic nucleus]]. It is approximately equal to the [[Physics:Atomic mass|''atomic'' (also known as ''isotopic'') mass]] of the [[Physics:Atom|atom]] expressed in atomic mass units. Since protons and neutrons are both [[Physics:Baryon|baryon]]s, the mass number ''A'' is identical with the [[Physics:Baryon number|baryon number]] ''B'' of the nucleus (and also of the whole atom or [[Physics:Ion|ion]]). The mass number is different for each different [[Physics:Isotope|isotope]] of a [[Chemistry:Chemical element|chemical element]]. Hence, the difference between the mass number and the [[Physics:Atomic number|atomic number]]&nbsp;''Z'' gives the [[Physics:Neutron number|number of neutrons]] (''N'') in a given nucleus: {{nowrap|1=''N'' = ''A'' − ''Z''}}.<ref>{{cite web|url=http://education.jlab.org/qa/pen_number.html|title=How many protons, electrons and neutrons are in an atom of krypton, carbon, oxygen, neon, silver, gold, etc...?|publisher=Thomas Jefferson National Accelerator Facility|access-date=2008-08-27}}</ref>

The mass number is written either after the element name or as a superscript to the left of an element's symbol. For example, the most common isotope of [[Chemistry:Carbon|carbon]] is [[Physics:Carbon-12|carbon-12]], or {{SimpleNuclide2|carbon|12}}, which has 6 protons and 6 neutrons. The full isotope symbol would also have the atomic number (''Z'') as a subscript to the left of the element symbol directly below the mass number: {{nuclide|carbon|12}}.<ref>{{cite web|url=http://www.fordhamprep.org/gcurran/sho/sho/lessons/lesson35.htm|title=Elemental Notation and Isotopes|publisher=Science Help Online|access-date=2008-08-27|url-status=dead|archive-url=https://web.archive.org/web/20080913063710/http://www.fordhamprep.org/gcurran/sho/sho/lessons/lesson35.htm|archive-date=2008-09-13}}</ref>}}
{{term|term= '''[[Physics:Mass spectrometry|Mass spectrometry]]'''}}{{defn|defn=(MS), is an analytical technique that is used to measure the [[Physics:Mass-to-charge ratio|mass-to-charge ratio]] of  [[Physics:Ion|ion]]s. The results are typically presented as a [[Physics:Mass spectrum|mass spectrum]], a plot of intensity as a function of the mass-to-charge ratio. Mass spectrometry is used in many different fields and is applied to pure samples as well as complex mixtures.}}
{{term|term= '''[[Physics:Material failure theory|Material failure theory]]'''}}{{defn|defn=Is an interdisciplinary field of [[Physics:Materials science|materials science]] and [[Physics:Solid mechanics|solid mechanics]] which attempts to [[Engineering:Failure analysis|predict the conditions]] under which solid [[Physics:Material|material]]s fail under the action of [[Structural load|external loads]]. The failure of a material is usually classified into brittle failure ([[Physics:Fracture|fracture]]) or ductile failure ([[Engineering:Yield (engineering)|yield]]). Depending on the conditions (such as [[Physics:Temperature|temperature]], state of [[Physics:Stress (mechanics)|stress]], loading rate) most materials can fail in a brittle or ductile manner or both. However, for most practical situations, a material may be classified as either brittle or ductile. 

In mathematical terms, failure theory is expressed in the form of various failure criteria which are valid for specific materials.  Failure criteria are functions in [[Stress–strain analysis|stress or strain space]] which separate "failed" states from "unfailed" states.  A precise physical definition of a "failed" state is not easily quantified and several working definitions are in use in the engineering community.  Quite often, phenomenological failure criteria of the same form are used to predict brittle failure and ductile yields.}}
{{term|term= '''Material properties'''}}{{defn|defn=A materials property is an intensive property of some [[Chemistry:Chemical change|material]], i.e., a [[Physics:Physical property|physical property]] that does not depend on the amount of the material. These quantitative properties may be used as a [[Metric (mathematics)|metric]] by which the benefits of one material versus another can be compared, thereby aiding in materials selection.}}
{{term|term= '''[[Physics:Materials science|Materials science]]'''}}{{defn|defn=The [[Philosophy:Interdisciplinarity|interdisciplinary]] field of materials science, also commonly termed '''materials science and engineering''', covers the design and discovery of new materials, particularly [[Physics:Solid|solid]]s. The intellectual origins of materials science stem from the [[Philosophy:Age of Enlightenment|Enlightenment]], when researchers began to use analytical thinking from [[Chemistry:Chemistry|chemistry]], [[Physics:Physics|physics]], and [[Engineering:Engineering|engineering]] to understand ancient, [[Philosophy:Empirical relationship|phenomenological]] observations in [[Chemistry:Metallurgy|metallurgy]] and [[Earth:Mineralogy|mineralogy]].<ref>{{cite book|last1= Eddy|first1= Matthew Daniel|title= The Language of Mineralogy: John Walker, Chemistry and the Edinburgh Medical School 1750–1800|date= 2008|publisher= Ashgate|url= https://www.academia.edu/1112014|url-status= live|archive-url= https://web.archive.org/web/20150903230852/http://www.academia.edu/1112014/The_Language_of_Mineralogy_John_Walker_Chemistry_and_the_Edinburgh_Medical_School_1750-1800_2008_|archive-date= 2015-09-03}}</ref><ref name=smith>{{cite book |last= Smith |first= Cyril Stanley |title= A Search for Structure |date= 1981 |publisher= MIT Press |isbn= 978-0262191913}}</ref> Materials science still incorporates elements of physics, chemistry, and engineering. As such, the field was long considered by academic institutions as a sub-field of these related fields. Beginning in the 1940s, materials science began to be more widely recognized as a specific and distinct field of science and engineering, and major technical universities around the world created dedicated schools for its study. 

Materials scientists emphasize understanding, how the history of a material (''processing'') influences its structure, and thus the material's properties and performance. The understanding of processing-structure-properties relationships is called the materials paradigm. This [[Philosophy:Paradigm|paradigm]] is used to advance understanding in a variety of research areas, including [[Engineering:Nanotechnology|nanotechnology]], [[Chemistry:Biomaterial|biomaterial]]s, and [[Chemistry:Metallurgy|metallurgy]]. 

Materials science is also an important part of [[Engineering:Forensic engineering|forensic engineering]] and [[Engineering:Failure analysis|failure analysis]]{{snd}} investigating materials, products, structures or components, which fail or do not function as intended, causing personal injury or damage to property. Such investigations are key to understanding, for example, the causes of various [[Engineering:Aviation accidents and incidents|aviation accidents and incidents]].}}
{{term|term= '''[[Mathematical optimization]]'''}}{{defn|defn=Mathematical optimization (alternatively spelled ''optimisation'') or '''mathematical programming''' is the selection of a best element, with regard to some criterion, from some set of available alternatives.<ref>"[http://glossary.computing.society.informs.org/index.php?page=nature.html The Nature of Mathematical Programming] {{webarchive|url=https://web.archive.org/web/20140305080324/http://glossary.computing.society.informs.org/index.php?page=nature.html |date=2014-03-05 }}," ''Mathematical Programming Glossary'', INFORMS Computing Society.</ref> Optimization problems of sorts arise in all quantitative disciplines from [[Computer science|computer science]] and [[Engineering:Engineering|engineering]] to [[Operations research|operations research]] and [[Finance:Economics|economics]], and the development of solution methods has been of interest in [[Mathematics|mathematics]] for centuries.<ref>{{cite book |last1=Du |first1=D. Z. |last2=Pardalos |first2=P. M. |last3=Wu |first3=W. |year=2008 |chapter=History of Optimization |editor-last=Floudas |editor-first=C. |editor2-last=Pardalos |editor2-first=P. |title=Encyclopedia of Optimization |publisher=Springer |location=Boston |pages=1538–1542 }}</ref>

In the simplest case, an [[Optimization problem|optimization problem]] consists of [[Maxima and minima|maximizing or minimizing]] a [[Function of a real variable|real function]] by systematically choosing [[Argument of a function|input]] values from within an allowed set and computing the [[Value (mathematics)|value]] of the function. The generalization of optimization theory and techniques to other formulations constitutes a large area of [[Applied mathematics|applied mathematics]]. More generally, optimization includes finding "best available" values of some objective function given a defined [[Domain of a function|domain]] (or input), including a variety of different types of objective functions and different types of domains.}}
{{term|term= '''[[Physics:Mathematical physics|Mathematical physics]]'''}}{{defn|defn=Refers to the development of [[Mathematics|mathematical]] methods for application to problems in [[Physics:Physics|physics]]. The ''[[Physics:Journal of Mathematical Physics|Journal of Mathematical Physics]]'' defines the field as "the application of mathematics to problems in physics and the development of mathematical methods suitable for such applications and for the formulation of physical theories".<ref>Definition from the ''Journal of Mathematical Physics''. {{cite web |url=http://jmp.aip.org/jmp/staff.jsp |title=Archived copy |access-date=2006-10-03 |url-status=dead |archive-url=https://web.archive.org/web/20061003233339/http://jmp.aip.org/jmp/staff.jsp |archive-date=2006-10-03 }}</ref>}}
{{term|term= '''[[Mathematics]]'''}}{{defn|defn=Includes the study of such topics as [[Quantity|quantity]] ([[Number theory|number theory]]),<ref name="OED">{{cite web |url=http://oed.com/view/Entry/114974 |title=mathematics, ''n.'' |publisher=Oxford University Press |website=Oxford English Dictionary |year=2012 |access-date=June 16, 2012 |quote=The science of space, number, quantity, and arrangement, whose methods involve logical reasoning and usually the use of symbolic notation, and which includes geometry, arithmetic, algebra, and analysis. |archive-url=https://web.archive.org/web/20191116075558/https://www.oed.com/view/Entry/114974 |archive-date=November 16, 2019 |url-status=live }}</ref> [[Mathematical structure|structure]] ([[Algebra|algebra]]),<ref name="Kneebone">{{cite book |title=Mathematical Logic and the Foundations of Mathematics: An Introductory Survey |publisher=Dover |author=Kneebone, G.T. |year=1963 |page=[https://books.google.com/books?id=tCXxf4vbXCcC&pg=PA4 4] |isbn=978-0-486-41712-7 |quote=Mathematics&nbsp;... is simply the study of abstract structures, or formal patterns of connectedness.}}</ref> [[Space|space]] ([[Geometry|geometry]]),<ref name=OED/> and [[Calculus|change]] ([[Mathematical analysis|analysis]]).<ref name="LaTorre">{{cite book |title=Calculus Concepts: An Informal Approach to the Mathematics of Change |publisher=Cengage Learning |first1=Donald R. |last1=LaTorre |first2=John W. |last2=Kenelly |first3=Sherry S. |last3=Biggers |first4=Laurel R. |last4=Carpenter |first5=Iris B. |last5=Reed |first6=Cynthia R. |last6=Harris |year=2011 |page=[https://books.google.com/books?id=1Ebu2Tij4QsC&pg=PA2 2] |isbn=978-1-4390-4957-0 |quote=Calculus is the study of change—how things change, and how quickly they change.}}</ref><ref name="Ramana">{{cite book |title=Applied Mathematics |publisher=Tata McGraw–Hill Education |author=Ramana |year=2007 |page=[https://books.google.com/books?id=XCRC6BeKhIIC&pg=SA2–PA10 2.10] |isbn=978-0-07-066753-2 |quote=The mathematical study of change, motion, growth or decay is calculus.}}</ref><ref name="Ziegler">{{cite book |title=An Invitation to Mathematics: From Competitions to Research |publisher=Springer |author=Ziegler, Günter M. |year=2011 |page=[https://books.google.com/books?id=9TATfteVeVYC&pg=PR7 vii] |isbn=978-3-642-19532-7 |chapter=What Is Mathematics?}}</ref><!--<<< Please do NOT change the opening sentence without discussion; much time and discussion have been invested in its current form.--> It has no generally accepted [[Philosophy:Definitions of mathematics|definition]].<ref name="Mura">{{cite journal|author=Mura, Roberta|date=Dec 1993|title=Images of Mathematics Held by University Teachers of Mathematical Sciences|journal=Educational Studies in Mathematics|volume=25|issue=4|pages=375–85|doi=10.1007/BF01273907|jstor=3482762|s2cid=122351146}}</ref><ref name="Runge">{{cite book|author1=Tobies, Renate|title=Iris Runge: A Life at the Crossroads of Mathematics, Science, and Industry|title-link=Iris Runge|author2=Helmut Neunzert|publisher=Springer|year=2012|isbn=978-3-0348-0229-1|page=[https://books.google.com/books?id=EDm0eQqFUQ4C&pg=PA9 9]|quote=[I]t is first necessary to ask what is meant by ''mathematics'' in general. Illustrious scholars have debated this matter until they were blue in the face, and yet no consensus has been reached about whether mathematics is a natural science, a branch of the humanities, or an art form.|name-list-style=amp}}</ref>

Mathematicians seek and use [[Philosophy:Pattern|pattern]]s<ref>
 Steen, L.A. (April 29, 1988). The Science of Patterns Science, 240: 611–16. And summarized at Association for Supervision and Curriculum Development [https://web.archive.org/web/20101028101034/http://www.ascd.org/publications/curriculum-handbook/409/chapters/The-Future-of-Mathematics-Education.aspx Archived] October 28, 2010, at the Wayback Machine, www.ascd.org.

</ref><ref>Devlin, Keith, Mathematics: The Science of Patterns: The Search for Order in Life, Mind and the Universe (Scientific American Paperback Library) 1996, ISBN 978-0-7167-5047-5</ref> to formulate new [[Conjecture|conjecture]]s; they resolve the [[Truth|truth]] or falsity of such by [[Mathematical proof|mathematical proof]]. When [[Mathematical structure|mathematical structure]]s are good models of real phenomena, mathematical reasoning can be used to provide insight or predictions about [[Earth:Nature|nature]]. Through the use of [[Abstraction (mathematics)|abstraction]] and [[Logic|logic]], mathematics developed from [[Counting|counting]], [[Calculation|calculation]], [[Measurement|measurement]], and the systematic study of the [[Shape|shape]]s and [[Physics:Motion|motions]] of physical objects. Practical mathematics has been a human activity from as far back as written records exist. The [[Research|research]] required to solve mathematical problems can take years or even centuries of sustained inquiry.}}
{{term|term= '''[[Matrix (mathematics)|Matrix]]'''}}{{defn|defn=In [[Mathematics|mathematics]], a matrix (plural ''matrices'') is a [[Rectangle|rectangular]] array or table of [[Number|number]]s, [[Symbol (formal)|symbol]]s, or [[Expression (mathematics)|expression]]s, arranged in rows and columns, which is used to represent a [[Philosophy:Mathematical object|mathematical object]] or a property of such an object. For example, 
:<math>\begin{bmatrix}1 & 9 & -13 \\20 & 5 & -6 \end{bmatrix}</math>
is a matrix with two rows and three columns; one say often a "two by three matrix", a "{{math|2×3}}-matrix", or a matrix of dimension {{math|2×3}}.

Without further specifications, matrices represent linear maps, and allow explicit computations in [[Linear algebra|linear algebra]]. Therefore, the study of matrices is a large part of linear algebra, and most properties and [[Operation (mathematics)|operations]] of abstract linear algebra can be expressed in terms of matrices. For example, [[Matrix multiplication|matrix multiplication]] represents [[Function composition|composition]] of linear maps.

Not all matrices are related to linear algebra. This is in particular the case, in [[Graph theory|graph theory]], of [[Incidence matrix|incidence matrices]] and [[Adjacency matrix|adjacency matrices]].<ref>However, in the case of adjacency matrices, [[Matrix multiplication|matrix multiplication]] or a variant of it allows the simultaneous computation of the number of paths between any two vertices, and of the shortest length of a path between two vertices.</ref> }}
{{term|term= '''[[Physics:Matter|Matter]]'''}}{{defn|defn=In [[Physics:Classical physics|classical physics]] and general [[Chemistry:Chemistry|chemistry]], matter is any substance that has [[Physics:Mass|mass]] and takes up space by having [[Physics:Volume|volume]].<ref name=Penrose/> All everyday objects that can be touched are ultimately composed of [[Physics:Atom|atom]]s, which are made up of interacting [[Physics:Subatomic particle|subatomic particle]]s, and in everyday as well as scientific usage, "matter" generally includes atoms and anything made up of them, and any particles (or combination of particles) that act as if they have both [[Physics:Rest mass|rest mass]] and volume. However it does not include [[Physics:Massless particle|massless particle]]s such as [[Physics:Photon|photon]]s, or other energy phenomena or waves such as [[Physics:Light|light]].<ref name=Penrose >
{{cite book
 |author= R. Penrose
 |date=1991
 |chapter=The mass of the classical vacuum
 |title=The Philosophy of Vacuum
 |chapter-url=https://books.google.com/books?id=ZU1LL4IbDKcC&pg=PA21
 |pages=21–26
 |publisher=[[Organization:Oxford University Press|Oxford University Press]]
 |isbn=978-0-19-824449-3
}}</ref>{{rp|21}}<ref name=mcgrawhill>
{{cite encyclopedia
 |title=Matter (physics)
 |url=http://www.accessscience.com/abstract.aspx?id=410600&referURL=http%3a%2f%2fwww.accessscience.com%2fcontent.aspx%3fid%3d410600
 |encyclopedia=McGraw-Hill's Access Science: Encyclopedia of Science and Technology Online
 |access-date=2009-05-24
 |url-status=dead
 |archive-url=https://web.archive.org/web/20110617073828/http://www.accessscience.com/abstract.aspx?id=410600&referURL=http%3A%2F%2Fwww.accessscience.com%2Fcontent.aspx%3Fid%3D410600
 |archive-date=17 June 2011 }}</ref> Matter exists in various [[Physics:State of matter|states]] (also known as [[Physics:Phase (matter)|phases]]). These include classical everyday phases such as [[Physics:Solid|solid]], [[Physics:Liquid|liquid]], and [[Physics:Gas|gas]] – for example [[Chemistry:Water|water]] exists as ice, liquid water, and gaseous steam – but other states are possible, including [[Physics:Plasma|plasma]], [[Physics:Bose–Einstein condensate|Bose–Einstein condensate]]s, [[Physics:Fermionic condensate|fermionic condensate]]s, and [[Physics:Quark–gluon plasma|quark–gluon plasma]].<ref name=RHIC>
{{cite press
 |date=18 April 2005
 |url=http://www.bnl.gov/bnlweb/pubaf/pr/pr_display.asp?prid=05-38
 |title=RHIC Scientists Serve Up "Perfect" Liquid
 |publisher=[[Organization:Brookhaven National Laboratory|Brookhaven National Laboratory]]
 |access-date=2009-09-15
}}</ref>}}
{{term|term= '''Maximum-distortion energy theory'''}}{{defn|defn=.}}
{{term|term= '''Maximum-normal-stress theory'''}}{{defn|defn=.}}
{{term|term= '''Maximum shear stress'''}}{{defn|defn=.}}
{{term|term= '''[[Physics:Maxwell's equations|Maxwell's equations]]'''}}{{defn|defn=Are a set of coupled [[Partial differential equation|partial differential equation]]s that, together with the [[Physics:Lorentz force|Lorentz force]] law, form the foundation of [[Physics:Classical electromagnetism|classical electromagnetism]], classical [[Physics:Optics|optics]], and electric circuits. 
The equations provide a mathematical model for electric, optical, and radio technologies, such as power generation, electric motors, [[Engineering:Wireless|wireless]] communication, lenses, radar etc. They describe how [[Physics:Electric field|electric]] and [[Physics:Magnetic field|magnetic field]]s are generated by [[Physics:Electric charge|charges]], [[Physics:Electric current|currents]], and changes of the fields.<ref group="note">''Electric'' and ''magnetic'' fields, according to the [[Physics:Theory of relativity|theory of relativity]], are the components of a single electromagnetic field.</ref> The equations are named after the physicist and mathematician [[Biography:James Clerk Maxwell|James Clerk Maxwell]], who, in 1861 and 1862, published an early form of the equations that included the Lorentz force law. Maxwell first used the equations to propose that light is an electromagnetic phenomenon.

An important consequence of Maxwell's equations is that they demonstrate how fluctuating electric and magnetic fields propagate at a constant speed (''[[Physics:Speed of light|c]]'') in a vacuum. Known as [[Physics:Electromagnetic radiation|electromagnetic radiation]], these waves may occur at various wavelengths to produce a [[Physics:Electromagnetic spectrum|spectrum]] of light from [[Radio wave|radio wave]]s to [[Physics:Gamma ray|gamma ray]]s.}} 
{{term|term= '''[[Mean]]'''}}{{defn|defn=There are several kinds of '''mean''' in [[Mathematics|mathematics]], especially in [[Statistics|statistics]]:

For a [[Data set|data set]], the [[Arithmetic mean|arithmetic mean]], also known as [[Average|average]] or arithmetic average, is a central value of a finite set of numbers: specifically, the sum of the values divided by the number of values. The arithmetic mean of a set of numbers ''x''<sub>1</sub>, ''x''<sub>2</sub>, ..., x''<sub>n</sub>'' is typically denoted by <math>\bar{x}</math>{{refn|Pronounced "''x'' bar".|group="note"}}. If the data set were based on a series of observations obtained by [[Sampling (statistics)|sampling]] from a [[Statistical population|statistical population]], the arithmetic mean is the '''sample mean''' (denoted <math>\bar{x}</math>) to distinguish it from the mean, or [[Expected value|expected value]], of the underlying distribution, the '''population mean''' (denoted '''<math>\mu</math>''' or '''<math>\mu_x</math>'''{{refn|Greek letter μ, for "mean", pronounced /'mjuː/.|group="note"}}).<ref name=":0">{{Cite web|date=2020-04-26|title=List of Probability and Statistics Symbols|url=https://mathvault.ca/hub/higher-math/math-symbols/probability-statistics-symbols/|access-date=2020-08-21|website=Math Vault|language=en-US}}</ref><ref>Underhill, L.G.; Bradfield d. (1998) ''Introstat'', Juta and Company Ltd. {{isbn|0-7021-3838-X}} [https://books.google.com/books?id=f6TlVjrSAsgC&lpg=PP1&pg=PA181#v=onepage&q&f=false p. 181]</ref>

In [[Probability|probability]] and [[Statistics|statistics]], the '''population mean''', or expected value, is a measure of the [[Central tendency|central tendency]] either of a [[Probability distribution|probability distribution]] or of a [[Random variable|random variable]] characterized by that distribution.<ref>{{cite book|last=Feller|first=William|title=Introduction to Probability Theory and its Applications, Vol I|year=1950|publisher=Wiley|isbn=0471257087|pages=221}}</ref> In a discrete probability distribution of a random variable ''X'', the mean is equal to the sum over every possible value weighted by the probability of that value; that is, it is computed by taking the product of each possible value ''x'' of ''X'' and its probability ''p''(''x''), and then adding all these products together, giving <math>\mu = \sum x p(x)....</math>.<ref>Elementary Statistics by Robert R. Johnson and Patricia J. Kuby, [https://books.google.com/books?id=DWCAh7jWO98C&lpg=PP1&pg=PA279#v=onepage&q&f=false p. 279]</ref><ref name=":1">{{Cite web|last=Weisstein|first=Eric W.|title=Population Mean|url=https://mathworld.wolfram.com/PopulationMean.html|access-date=2020-08-21|website=mathworld.wolfram.com|language=en}}</ref> An analogous formula applies to the case of a continuous probability distribution. Not every probability distribution has a defined mean (see the [[Cauchy distribution]] for an example). Moreover, the mean can be infinite for some distributions.

For a finite population, the '''population mean''' of a property is equal to the arithmetic mean of the given property, while considering every member of the population. For example, the population mean height is equal to the sum of the heights of every individual—divided by the total number of individuals. The sample mean may differ from the population mean, especially for small samples. The [[Law of large numbers|law of large numbers]] states that the larger the size of the sample, the more likely it is that the sample mean will be close to the population mean.<ref>Schaum's Outline of Theory and Problems of Probability by Seymour Lipschutz and Marc Lipson, [https://books.google.com/books?id=ZKdqlw2ZnAMC&lpg=PP1&pg=PA141#v=onepage&q&f=false p. 141]</ref>

Outside probability and statistics, a wide range of other notions of mean are often used in [[Geometry|geometry]] and [[Mathematical analysis|mathematical analysis]].}}
{{term|term= '''[[Central tendency|Measure of central tendency]]'''}}{{defn|defn=In [[Statistics|statistics]], a '''central tendency''' (or '''measure of central tendency''') is a central or typical value for a [[Probability distribution|probability distribution]].<ref name=Weisberg>Weisberg H.F (1992) ''Central Tendency and Variability'', Sage University Paper Series on Quantitative Applications in the Social Sciences,  {{ISBN|0-8039-4007-6}} p.2</ref> It may also be called a '''center''' or '''location''' of the distribution. Colloquially, measures of central tendency are often called ''averages.'' The term ''central tendency'' dates from the late 1920s.<ref name=Upton/>

The most common measures of central tendency are the [[Arithmetic mean|arithmetic mean]], the [[Median|median]], and the [[Mode (statistics)|mode]].  A middle tendency can be calculated for either a finite set of values or for a theoretical distribution, such as the [[Normal distribution|normal distribution]]. Occasionally authors use central tendency to denote "the tendency of quantitative [[Data|data]] to cluster around some central value."<ref name=Upton>Upton, G.; Cook, I. (2008) ''Oxford Dictionary of Statistics'', OUP {{ISBN|978-0-19-954145-4}} (entry for "central tendency")</ref><ref name=Dodge1>Dodge, Y. (2003) ''The Oxford Dictionary of Statistical Terms'', OUP for International Statistical Institute. {{ISBN|0-19-920613-9}} (entry for "central tendency")</ref>

The central tendency of a distribution is typically contrasted with its ''[[Statistical dispersion|dispersion]]'' or ''variability''; dispersion and central tendency are the often characterized properties of distributions. Analysis may judge whether data has a strong or a weak central tendency based on its dispersion.}}
{{term|term= '''[[Physics:Mechanical advantage|Mechanical advantage]]'''}}{{defn|defn=Is a measure of the [[Physics:Force|force]] amplification achieved by using a tool, mechanical device or machine system. The device trades off input forces against movement to obtain a desired amplification in the output force.  The model for this is the ''law of the [[Engineering:Lever|lever]].''  Machine components designed to manage forces and movement in this way are called [[Engineering:Mechanism (engineering)|mechanism]]s.<ref name="Uicker">{{cite book | last1=Uicker | first1=John J.| first2=G. R.|last2=Pennock|first3=J. E.|last3=Shigley|title=Theory of machines and mechanisms | publisher=Oxford University Press | publication-place=New York | year=2011 | isbn=978-0-19-537123-9 }}</ref>  
An ideal mechanism transmits power without adding to or subtracting from it.  This means the ideal mechanism does not include a power source, is frictionless, and is constructed from rigid bodies that do not deflect or wear.  The performance of a real system relative to this ideal is expressed in terms of efficiency factors that take into account departures from the ideal.}}
{{term|term= '''[[Engineering:Mechanical engineering|Mechanical engineering]]'''}}{{defn|defn=Is an [[Engineering:Engineering|engineering]] branch that combines [[Engineering:Engineering physics|engineering physics]] and [[Engineering:Engineering mathematics|mathematics]] principles with [[Physics:Materials science|materials science]] to [[Design|design]], analyze, manufacture, and maintain [[Engineering:Mechanical system|mechanical system]]s.<ref>{{cite web |url=https://me.columbia.edu/what-mechanical-engineering |title= What is Mechanical Engineering?}}</ref> It is one of the oldest and broadest of the [[Engineering:List of engineering branches|engineering branches]].}}
{{term|term= '''[[Physics:Mechanical filter|Mechanical filter]]'''}}{{defn|defn=Is a [[Filter (signal processing)|signal processing filter]] usually used in place of an [[Engineering:Electronic filter|electronic filter]] at [[Engineering:Radio frequency|radio frequencies]].  Its purpose is the same as that of a normal electronic filter: to pass a range of signal frequencies, but to block others.  The filter acts on mechanical vibrations which are the analogue of the electrical signal.  At the input and output of the filter, [[Engineering:Transducer|transducer]]s convert the electrical signal into, and then back from, these mechanical vibrations.}}
{{term|term= '''[[Physics:Mechanical wave|Mechanical wave]]'''}}{{defn|defn=Is a [[Wave|wave]] that is an oscillation of [[Physics:Matter|matter]], and therefore transfers energy through a [[Physics:Transmission medium|medium]].<ref>Giancoli, D. C. (2009) Physics for scientists & engineers with modern physics (4th ed.). Upper Saddle River, N.J.: Pearson Prentice Hall.</ref> While waves can move over long distances, the movement of the [[Physics:Transmission medium|medium of transmission]]—the material—is limited. Therefore, the oscillating material does not move far from its initial equilibrium position. Mechanical waves transport energy. This energy propagates in the same direction as the wave. Any kind of wave (mechanical or electromagnetic) has a certain energy. Mechanical waves can be produced only in media which possess [[Physics:Elasticity|elasticity]] and [[Physics:Inertia|inertia]].}}
{{term|term= '''[[Physics:Mechanics|Mechanics]]'''}}{{defn|defn=Is the area of [[Physics:Physics|physics]] concerned with the motions of [[Philosophy:Physical object|physical object]]s, more specifically the relationships among force, matter, and motion.<ref>{{Cite book|last=Young, Hugh D. (Hugh David), 1930-|first=|url=https://www.worldcat.org/oclc/1104689918|title=Sears and Zemansky's university physics : with modern physics|publisher=|others=Freedman, Roger A., Ford, A. Lewis (Albert Lewis), Estrugo, Katarzyna Zulteta|year=|isbn=1-292-31473-7|edition=Fifteenth edition in SI units|location=Harlow|pages=62|oclc=1104689918}}</ref> [[Physics:Force|Force]]s applied to objects result in [[Displacement (vector)|displacements]], or changes of an object's position relative to its environment.
This branch of [[Physics:Physics|physics]] has its origins in {{wipe|Ancient Greece}} with the writings of [[Biography:Aristotle|Aristotle]] and [[Biography:Archimedes|Archimedes]]<ref>Dugas, Rene. A History of Classical Mechanics. New York, NY: Dover Publications Inc, 1988, pg 19.</ref><ref>Rana, N.C., and Joag, P.S. Classical Mechanics. West Petal Nagar, New Delhi. Tata McGraw-Hill, 1991, pg 6.</ref><ref>Renn, J., Damerow, P., and McLaughlin, P. Aristotle, Archimedes, Euclid, and the Origin of Mechanics: The Perspective of Historical Epistemology. Berlin: Max Planck Institute for the History of Science, 2010, pg 1-2.</ref> (see [[Physics:History of classical mechanics|History of classical mechanics]] and [[Timeline of classical mechanics]]). During the [[History:Early modern period|early modern period]], scientists such as Galileo, [[Biography:Johannes Kepler|Kepler]], and [[Biography:Isaac Newton|Newton]] laid the foundation for what is now known as [[Physics:Classical mechanics|classical mechanics]].
It is a branch of [[Physics:Classical physics|classical physics]] that deals with particles that are either at rest or are moving with velocities significantly less than the speed of light. 
It can also be defined as a branch of science which deals with the motion of and forces on bodies not in the quantum realm. The field is today less widely understood in terms of quantum theory.}}
{{term|term= '''[[Engineering:Mechanism (engineering)|Mechanism]]'''}}{{defn|defn=Is a device that transforms input forces and movement into a desired set of output forces and movement. Mechanisms generally consist of moving components which may include:
* [[Physics:Gear|Gear]]s and [[Engineering:Gear train|gear train]]s;
* Belts and [[Physics:Chain drive|chain drive]]s;
* [[Engineering:Cam|Cam]]s and [[Engineering:Cam follower|follower]]s;
* [[Engineering:Linkage (mechanical)|Linkages]];
* Friction devices, such as brakes or [[Engineering:Clutch|clutch]]es;
* Structural components such as a frame, fasteners, bearings, springs, or lubricants;
* Various [[Engineering:Machine element|machine element]]s, such as splines, pins, or keys.}}
{{term|term= '''[[Median]]'''}}{{defn|defn=In [[Statistics|statistics]] and [[Probability theory|probability theory]], the median is the value separating the higher half from the lower half of a [[Sample (statistics)|data sample]], a [[Statistical population|population]], or a [[Probability distribution|probability distribution]]. For a [[Data set|data set]], it may be thought of as "the middle" value. The basic feature of the median in describing data compared to the [[Arithmetic mean|mean]] (often simply described as the "average") is that it is not [[Skewness|skewed]] by a small proportion of extremely large or small values, and therefore provides a better representation of a "typical" value. [[Finance:Median income|Median income]], for example, may be a better way to suggest what a "typical" income is, because income distribution can be very skewed. The median is of central importance in [[Robust statistics|robust statistics]], as it is the most resistant statistic, having a breakdown point of 50%: so long as no more than half the data are contaminated, the median is not an arbitrarily large or small result.}}
{{term|term= '''[[Physics:Melting|Melting]]'''}}{{defn|defn=Melting, or [[Physics:Enthalpy of fusion|fusion]], is a physical process that results in the [[Physics:Phase transition|phase transition]] of a [[Chemistry:Chemical substance|substance]] from a [[Physics:Solid|solid]] to a [[Physics:Liquid|liquid]]. This occurs when the [[Physics:Internal energy|internal energy]] of the solid increases, typically by the application of [[Physics:Heat|heat]] or [[Physics:Pressure|pressure]], which increases the substance's [[Physics:Temperature|temperature]] to the [[Physics:Melting point|melting point]]. At the melting point, the ordering of [[Physics:Ion|ion]]s or [[Physics:Molecule|molecule]]s in the solid breaks down to a less ordered state, and the solid ''melts'' to become a liquid.}}
{{term|term= '''[[Physics:Melting point|Melting point]]'''}}{{defn|defn=The melting point (or, rarely, '''liquefaction point''') of a substance is the [[Physics:Temperature|temperature]] at which it changes [[Physics:State of matter|state]] from [[Physics:Solid|solid]] to [[Physics:Liquid|liquid]]. At the melting point the solid and liquid phase exist in [[Physics:Thermodynamic equilibrium|equilibrium]]. The melting point of a substance depends on [[Physics:Pressure|pressure]] and is usually specified at a [[Standard conditions for temperature and pressure|standard pressure]] such as 1 [[Physics:Atmosphere (unit)|atmosphere]] or 100 [[Pascal (unit)|kPa]].

When considered as the temperature of the reverse change from liquid to solid, it is referred to as the '''freezing point''' or '''crystallization point'''. Because of the ability of substances to [[Physics:Supercooling|supercool]], the freezing point can easily appear to be below its actual value. When the "characteristic freezing point" of a substance is determined, in fact the actual methodology is almost always "the principle of observing the disappearance rather than the formation of ice, that is, the melting point."<ref>{{cite journal |last1=Ramsay |first1=J. A. |title=A New Method of Freezing-Point Determination for Small Quantities |journal=Journal of Experimental Biology |date=1 May 1949 |volume=26 |issue=1 |pages=57–64 |doi=10.1242/jeb.26.1.57 |pmid=15406812 |url=http://jeb.biologists.org/cgi/pmidlookup?view=long&pmid=15406812 }}</ref>}}
{{term|term= '''[[Physics:Meson|Meson]]'''}}{{defn|defn=In [[Physics:Particle physics|particle physics]], mesons are [[Physics:Hadron|hadron]]ic [[Physics:Subatomic particle|subatomic particle]]s composed of an equal number of quarks and antiquarks, usually one of each, bound together by strong interactions. Because mesons are composed of quark subparticles, they have a meaningful physical size, a diameter of roughly one femtometer (1×10{{sup|−15}}&nbsp;m),<ref>D. Griffiths (2008)</ref> which is about 0.6&nbsp;times the size of a [[Physics:Proton|proton]] or [[Physics:Neutron|neutron]]. All mesons are unstable, with the longest-lived lasting for only a few hundredths of a microsecond.  Heavier mesons decay to lighter mesons and ultimately to stable [[Physics:Electron|electron]]s, [[Physics:Neutrino|neutrino]]s and [[Physics:Photon|photon]]s.}}
{{term|term= '''[[Chemistry:Metallic bonding|Metallic bonding]]'''}}{{defn|defn=Is a type of [[Chemistry:Chemical bond|chemical bond]]ing that arises from the electrostatic attractive force between conduction electrons (in the form of an electron cloud of [[Physics:Delocalized electron|delocalized electron]]s) and positively charged [[Chemistry:Metal|metal]] [[Physics:Ion|ion]]s. It may be described as the sharing of ''free'' electrons among a [[Chemistry:Crystal structure|structure]] of positively charged ions (cations). Metallic bonding accounts for many [[Physics:Physical property|physical properties]] of metals, such as [[Physics:Strength of materials|strength]], [[Physics:Ductility|ductility]], [[Physics:Thermal conductivity|thermal]] and [[Physics:Electrical resistivity and conductivity|electrical resistivity and conductivity]], [[Physics:Opacity (optics)|opacity]], and [[Earth:Lustre (mineralogy)|luster]].<ref>[http://www.chemguide.co.uk/atoms/bonding/metallic.html Metallic bonding]. chemguide.co.uk</ref><ref>[http://www.chemguide.co.uk/atoms/structures/metals.html Metal structures]. chemguide.co.uk</ref><ref>[http://hyperphysics.phy-astr.gsu.edu/hbase/chemical/bond.html Chemical Bonds]. chemguide.co.uk</ref><ref>[https://web.archive.org/web/19991018204506/http://www.physics.ohio-state.edu/%7Eaubrecht/physics133.html "Physics 133 Lecture Notes" Spring, 2004. Marion Campus]. physics.ohio-state.edu</ref>

Metallic bonding is not the only type of [[Chemistry:Chemical bond|chemical bond]]ing a metal can exhibit, even as a pure substance. For example, elemental [[Chemistry:Gallium|gallium]] consists of [[Chemistry:Covalent bond|covalently-bound]] pairs of atoms in both liquid and solid-state—these pairs form a [[Chemistry:Crystal structure|crystal structure]] with metallic bonding between them. Another example of a metal–metal covalent bond is the mercurous ion ({{chem|Hg|2|2+}}).}}
{{term|term= '''Middle-out'''}} {{defn|defn= A combination of top-down and bottom-up design.<ref>{{cite web |last1=John |first1=Blyler |title=What is middle-out systems engineering? |url=https://www.designnews.com/electronics-test/what-middle-out-systems-engineering |website=DesignNews |access-date=28 September 2020 |date=27 December 2019}}</ref>}}
{{term|term= '''[[Mid-range]]'''}}{{defn|defn=In [[Statistics|statistics]], the mid-range or ''mid-extreme'' is a measure of [[Central tendency|central tendency]] of a [[Sample (statistics)|sample (statistics)]] defined as the [[Arithmetic mean|arithmetic mean]] of the maximum and minimum values of the [[Data set|data set]]:{{sfn|Dodge|2003}}

:<math>M=\frac{\max x + \min x}{2}.</math>

The mid-range is closely related to the [[Range (statistics)|range]], a measure of [[Statistical dispersion|statistical dispersion]] defined as the difference between maximum and minimum values.
The two measures are complementary in sense that if one knows the mid-range and the range, one can find the sample maximum and minimum values.

The mid-range is rarely used in practical statistical analysis, as it lacks efficiency as an estimator for most distributions of interest,  because it ignores all intermediate points, and lacks robustness, as outliers change it significantly. Indeed, it is one of the least efficient and least robust statistics. However, it finds some use in special cases: it is the maximally efficient estimator for the center of a uniform distribution, trimmed mid-ranges address robustness, and as an [[L-estimator]], it is simple to understand and compute.}}
{{term|term= '''[[Midhinge]]'''}}{{defn|defn=In [[Statistics|statistics]], the midhinge is the average of the first and third [[Quartile|quartile]]s and is thus a measure of [[Location parameter|location]].
Equivalently, it is the 25% [[Trimmed estimator|trimmed]] [[Mid-range|mid-range]] or 25% midsummary; it is an [[L-estimator]].

: <math>\operatorname{MH}(X) = \overline{Q_{1, 3}(X)} = \frac{Q_1(X) + Q_3(X)}{2} = \frac{P_{25}(X) + P_{75}(X)}{2} = M_{25}(X)</math>

The midhinge is related to the [[Interquartile range|interquartile range]] (IQR), the difference of the third and first [[Quartile|quartile]]s (i.e. <math>IQR = Q_3 - Q_1</math>), which is a measure of [[Statistical dispersion|statistical dispersion]]. The two are complementary in sense that if one knows the midhinge and the IQR, one can find the first and third quartiles.

The use of the term "hinge" for the lower or upper quartiles derives from [[Biography:John Tukey|John Tukey]]'s work on [[Exploratory data analysis|exploratory data analysis]] in the late 1970s,<ref>Tukey, J. W. (1977) ''Exploratory Data Analysis'', Addison-Wesley. {{ISBN|0-201-07616-0}}</ref> and "midhinge" is a fairly modern term dating from around that time. The midhinge is slightly simpler to calculate than the [[Trimean|trimean]] (<math>TM</math>), which originated in the same context and equals the average of the [[Median|median]] (<math>\tilde{X} = Q_2 = P_{50}</math>) and the midhinge.

: <math>\operatorname{MH}(X) = 2 \operatorname{TM}(X) - \operatorname{med}(X) = 2 \frac{Q_1 + 2Q_2 + Q3}{4} - Q_2</math>}}
{{term|term= '''[[Engineering:Mining engineering|Mining engineering]]'''}}{{defn|defn=Mining in the engineering discipline is the extraction of minerals from underneath, above or on the ground. '''Mining engineering''' is associated with many other disciplines, such as [[Chemistry:Mineral processing|mineral processing]], exploration, excavation, [[Earth:Geology|geology]], and [[Chemistry:Metallurgy|metallurgy]], [[Engineering:Geotechnical engineering|geotechnical engineering]] and [[Engineering:Surveying|surveying]]. A mining engineer may manage any phase of mining operations, from exploration and discovery of the mineral resources, through [[Feasibility study|feasibility study]], mine design, development of plans, [[Finance:Production (economics)|production]] and operations to mine closure.}}
{{term|term= '''Miller indices'''}}{{defn|defn=Miller indices form a notation system in [[Physics:Crystallography|crystallography]] for planes in [[Bravais lattice|crystal (Bravais) lattices]].

In particular, a family of [[Lattice plane|lattice plane]]s is determined by three [[Integer|integer]]s ''h'', ''k'', and&nbsp;''ℓ'', the ''Miller indices''.  They are written (hkℓ), and denote the family of planes orthogonal to <math>h\mathbf{b_1} + k\mathbf{b_2} + \ell\mathbf{b_3}</math>, where <math>\mathbf{b_i}</math> are the [[Basis (linear algebra)|basis]] of the [[Physics:Reciprocal lattice|reciprocal lattice]] vectors (note that the plane is not always orthogonal to the linear combination of direct lattice vectors <math>h\mathbf{a_1} + k\mathbf{a_2} + \ell\mathbf{a_3}</math> because the  lattice vectors need not be mutually orthogonal). By convention, negative integers are written with a bar, as in {{overline|3}} for&nbsp;−3.  The integers are usually written in lowest terms, i.e. their greatest common divisor should be&nbsp;1. Miller indices are also used to designate reflections in [[Physics:X-ray crystallography|X-ray crystallography]]. In this case the integers are not necessarily in lowest terms, and can be thought of as corresponding to planes spaced such that the reflections from adjacent planes would have a phase difference of exactly one wavelength (2π), regardless of whether there are atoms on all these planes or not.

There are also several related notations:<ref name="Ash">{{Cite book|url=https://archive.org/details/solidstatephysic00ashc|title=Solid state physics|last1=Ashcroft|first1=Neil W.|date=1976|publisher=Holt, Rinehart and Winston|last2=Mermin|first2=N. David|isbn=0030839939|location=New York|oclc=934604|url-access=registration}}</ref>
*the notation {hkℓ} denotes the set of all planes that are equivalent to (hkℓ) by the symmetry of the lattice.
In the context of crystal ''directions'' (not planes), the corresponding notations are:
*[hkℓ], with square instead of round brackets, denotes a direction in the basis of the ''direct'' lattice vectors instead of the reciprocal lattice; and
*similarly, the notation <hkℓ> denotes the set of all directions that are equivalent to [hkℓ] by symmetry.}}
{{term|term= '''[[Engineering:Mobile robot|Mobile robot]]'''}}{{defn|defn=Is a [[Engineering:Robot|robot]] that is capable of moving in the surrounding (locomotion).<ref name="tvt2">Hu, J.; Bhowmick, P.; Lanzon, A., "[https://ieeexplore.ieee.org/document/9468402 Group Coordinated Control of Networked Mobile Robots with Applications to Object Transportation]" IEEE Transactions on Vehicular Technology, 2021.</ref> Mobile robotics is usually considered to be a subfield of robotics and [[Information engineering (field)|information engineering]].<ref>{{Cite web|url=http://www.robots.ox.ac.uk/|title=Information Engineering Main/Home Page|website=www.robots.ox.ac.uk|language=en|access-date=2018-10-03}}</ref>

Mobile robots have the capability to move around in their environment and are not fixed to one physical location.  Mobile robots can be "autonomous" (AMR - autonomous mobile robot) which means they are capable of navigating an uncontrolled environment without the need for physical or electro-mechanical guidance devices.<ref name="tro">Hu, J.; Bhowmick, P.; Jang, I.;  Arvin, F.; Lanzon, A., "[https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=9423979 A Decentralized Cluster Formation Containment Framework for Multirobot Systems]" IEEE Transactions on Robotics, 2021.</ref>  Alternatively, mobile robots can rely on guidance devices that allow them to travel a pre-defined navigation route in relatively controlled space.<ref name="tcas">Hu, J.; Turgut, A.; Lennox, B.; Arvin, F., "[https://ieeexplore.ieee.org/abstract/document/9409965 Robust Formation Coordination of Robot Swarms with Nonlinear Dynamics and Unknown Disturbances: Design and Experiments]" IEEE Transactions on Circuits and Systems II: Express Briefs, 2021.</ref>  By contrast, industrial robots are usually more-or-less stationary, consisting of a jointed arm (multi-linked manipulator) and gripper assembly (or end effector), attached to a fixed surface. The joint-arm are controlled by linear actuator or servo motor or stepper motor.}}
{{term|term= '''[[Mode (statistics)|Mode]]'''}}{{defn|defn=The mode is the value that appears most often in a set of data values.<ref>Damodar N. Gujarati. ''Essentials of Econometrics''. McGraw-Hill Irwin. 3rd edition, 2006: p. 110.</ref> If {{mvar|'''X'''}} is a discrete random variable, the mode is the value {{mvar|x}}  (i.e, {{math|'''''X''''' {{=}} ''x''}}) at which the  [[Probability mass function|probability mass function]] takes its maximum value. In other words, it is the value that is most likely to be sampled.

Like the statistical [[Mean|mean]] and [[Median|median]], the mode is a way of expressing, in a (usually) single number, important information about a [[Random variable|random variable]] or a population. The numerical value of the mode is the same as that of the mean and median in a [[Normal distribution|normal distribution]], and it may be very different in highly skewed distributions.}}
{{term|term= '''Modulus of elasticity'''}}{{defn|defn=An '''elastic modulus''' (also known as '''modulus of elasticity''') is a quantity that measures an object or substance's resistance to being deformed elastically (i.e., non-permanently) when a [[Physics:Stress (mechanics)|stress]] is applied to it. The elastic modulus of an object is defined as the [[Slope|slope]] of its [[Physics:Stress–strain curve|stress–strain curve]] in the elastic deformation region:<ref>{{cite book| last = Askeland| first = Donald R.| last2 = Phulé| first2 = Pradeep P.| title = The science and engineering of materials| year = 2006| publisher = Cengage Learning| page = 198| edition = 5th| url = https://books.google.com/books?id=fRbZslUtpBYC&pg=PA198| isbn = 978-0-534-55396-8}}</ref> A stiffer material will have a higher elastic modulus. An elastic modulus has the form:

:<math>\delta \ \stackrel{\text{def}}{=}\  \frac {\text{stress}} {\text{strain}}</math>

where <var>[[Physics:Stress|stress]]</var> is the force causing the deformation divided by the area to which the force is applied and <var>[[Physics:Strain (materials science)|strain]]</var> is the ratio of the change in some parameter caused by the deformation to the original value of the parameter. Since strain is a dimensionless quantity, the units of <math>\delta</math> will be the same as the units of stress.<ref>{{cite book | last = Beer | first = Ferdinand P. | last2 = Johnston | first2 = E. Russell | last3 = Dewolf | first3 = John | last4 = Mazurek | first4 = David | title = Mechanics of Materials | url = https://archive.org/details/mechanicsmateria00beer_274 | url-access = limited | year = 2009 | publisher = McGraw Hill | page = [https://archive.org/details/mechanicsmateria00beer_274/page/n78 56] | isbn = 978-0-07-015389-9}}</ref>}}
{{term|term= '''[[Physics:Mohr's circle|Mohr's circle]]'''}} {{defn|defn= A graphical method of analyzing the three-dimensional stresses in  a system that has a loading force applied to it.}}
{{term|term= '''[[Chemistry:Molality|Molality]]'''}}{{defn|defn=Is a measure of the number of moles of solute in a solution corresponding to 1&nbsp;kg or 1000 g of solvent. This contrasts with the definition of molarity which is based on a specified [[Physics:Volume|volume]] of solution.

A commonly used unit for molality in [[Chemistry:Chemistry|chemistry]] is [[Mole (unit)|mol]]/[[Kilogram|kg]]. A solution of concentration 1&nbsp;mol/kg is also sometimes denoted as ''1 molal''. The unit ''mol/kg'' requires that molar mass be expressed in ''kg/mol'', instead of the usual ''g/mol'' or ''kg/kmol''.}}

{{term|term= '''[[Chemistry:Molar attenuation coefficient|Molar attenuation coefficient]]'''}}{{defn|defn=Is a measurement of how strongly a [[Chemistry:Chemical species|chemical species]] attenuates light at a given [[Wavelength|wavelength]]. It is an intrinsic property of the species. The [[International System of Units|SI unit]] of molar attenuation coefficient is the square metre per [[Mole (unit)|mole]] ({{nobreak|m<sup>2</sup>/mol}}), but in practice, quantities are usually expressed in terms of [[Physics:Molar concentration#Units|<span title="mol/L">M</span>]]<sup>−1</sup>⋅cm<sup>−1</sup> or L⋅mol<sup>−1</sup>⋅cm<sup>−1</sup> (the latter two units are both equal to {{nobreak|0.1 m<sup>2</sup>/mol}}). In older literature, the cm<sup>2</sup>/mol is sometimes used; 1 M<sup>−1</sup>⋅cm<sup>−1</sup> equals 1000 cm<sup>2</sup>/mol. The molar attenuation coefficient is also known as the '''molar extinction coefficient''' and '''molar absorptivity''', but the use of these alternative terms has been discouraged by the IUPAC.<ref>{{GoldBookRef|title=Extinction|file=E02293|accessdate=2015-03-15}}</ref><ref>{{GoldBookRef|title=Absorptivity|file=A00044|accessdate=2015-03-15}}</ref>}}



{{term|term= '''[[Physics:Molar concentration|Molar concentration]]'''}}{{defn|defn=Molar concentration (also called '''molarity''', '''amount concentration''' or '''substance concentration''') is a measure of the [[Chemistry:Concentration|concentration]] of a [[Chemistry:Chemical species|chemical species]], in particular of a solute in a [[Chemistry:Solution|solution]], in terms of [[Physics:Amount of substance|amount of substance]] per unit [[Physics:Volume|volume]] of solution. In [[Chemistry:Chemistry|chemistry]], the most commonly used unit for molarity is the number of [[Mole (unit)|moles]] per liter, having the unit symbol mol/L or [[Mole (unit)|mol]]⋅[[Decimetre|dm]]<sup>−3</sup> in SI unit. A solution with a concentration of 1&nbsp;mol/L is said to be 1&nbsp;molar, commonly designated as 1&nbsp;M. To avoid confusion with [[SI prefix]] [[Mega-|mega]], which has the same abbreviation, small caps ᴍ or italicized ''M'' are also used in journals and textbooks.<ref>{{cite web |url=https://tex.stackexchange.com/questions/191114/typography-of-unit-symbols-for-molar-and-liter-in-siunitx |title=Typography of unit symbols for Molar and Liter in siunitx |website=TeX - LaTeX Stack Exchange}}</ref>}}
{{term|term= '''[[Physics:Molar mass|Molar mass]]'''}}{{defn|defn=In [[Chemistry:Chemistry|chemistry]], the molar mass of a [[Chemistry:Chemical compound|chemical compound]] is defined as the [[Physics:Mass|mass]] of a sample of that compound divided by the [[Physics:Amount of substance|amount of substance]] in that sample, measured in [[Mole (unit)|moles]].<ref name="GreenBook">{{GreenBookRef|page=41}}</ref> It is the mass of 1&nbsp;mole of the substance or {{val|6.022|e=23}} particles, expressed in grams.  The molar mass is a bulk, not molecular, property of a substance. The molar mass is an ''average'' of many instances of the compound, which often vary in mass due to the presence of [[Physics:Isotope|isotope]]s. Most commonly, the molar mass is computed from the [[Physics:Standard atomic weight|standard atomic weight]]s and is thus a terrestrial average and a function of the relative abundance of the isotopes of the constituent atoms on Earth. The molar mass is appropriate for converting between the mass of a substance and the amount of a substance for bulk quantities.}}
{{term|term= '''[[Engineering:Molding (process)|Molding]]'''}}{{defn|defn=Molding (American English) or '''moulding''' (British and Commonwealth English; see [[Social:American and British English spelling differences|spelling differences]]) is the process of manufacturing by shaping liquid or pliable raw material using a rigid frame called a mold or matrix.<ref>{{cite web|url=http://www.merriam-webster.com/dictionary/molding|title=Molding – Definition of molding by Merriam-Webster|work=merriam-webster.com}}</ref> This itself may have been made using a pattern or model of the final object.}}
{{term|term= '''[[Physics:Molecule|Molecule]]'''}}{{defn|defn=A molecule is an electrically neutral group of two or more [[Physics:Atom|atom]]s held together by [[Chemistry:Chemical bond|chemical bond]]s.<ref name="iupac">{{GoldBookRef| title=Molecule|file=M04002|accessdate=23 February 2016}}</ref><ref>{{cite book| author= Ebbin, Darrell D.| title= General Chemistry |edition=3rd| date= 1990| publisher= Houghton Mifflin Co.| location= Boston| isbn= 978-0-395-43302-7}}</ref><ref>{{cite book| author= Brown, T.L. |author2=Kenneth C. Kemp |author3=Theodore L. Brown |author4=Harold Eugene LeMay |author5=Bruce Edward Bursten |title= Chemistry – the Central Science | url= https://archive.org/details/studentlectureno00theo | url-access= registration |edition=9th| date= 2003| publisher= Prentice Hall| location= New Jersey| isbn= 978-0-13-066997-1}}</ref><ref>{{cite book| last= Chang| first= Raymond| title= Chemistry | url= https://archive.org/details/chemistry00chan_0| url-access= registration|edition=6th| date= 1998| publisher= McGraw Hill| location= New York| isbn= 978-0-07-115221-1}}</ref><ref>{{cite book| author= Zumdahl, Steven S.| title= Chemistry |edition=4th| date= 1997| publisher= Houghton Mifflin| location= Boston| isbn= 978-0-669-41794-4}}</ref> Molecules are distinguished from [[Physics:Ion|ion]]s by their lack of electrical charge.

In quantum physics, [[Chemistry:Organic chemistry|organic chemistry]], and [[Biology:Biochemistry|biochemistry]], the distinction from ions is dropped and ''molecule'' is often used when referring to [[Physics:Polyatomic ion|polyatomic ion]]s.

In the [[Physics:Kinetic theory of gases|kinetic theory of gases]], the term ''molecule'' is often used for any gaseous [[Physics:Particle|particle]] regardless of its composition. This violates the definition that a molecule contain ''two or more'' atoms, since the noble gases are individual atoms.<ref>{{cite book| last= Chandra| first= Sulekh| title= Comprehensive Inorganic Chemistry| date= 2005| publisher= New Age Publishers| isbn= 978-81-224-1512-4}}</ref>

A molecule may be homonuclear, that is, it consists of atoms of one [[Chemistry:Chemical element|chemical element]], as with two atoms in the [[Chemistry:Oxygen|oxygen]] molecule (O<sub>2</sub>); or it may be heteronuclear, a [[Chemistry:Chemical compound|chemical compound]] composed of more than one element, as with [[Chemistry:Water (molecule)|water]] (two hydrogen atoms and one oxygen atom; H<sub>2</sub>O).

Atoms and complexes connected by [[Chemistry:Non-covalent interactions|non-covalent interactions]], such as [[Chemistry:Hydrogen bond|hydrogen bond]]s or ionic bonds, are typically not considered single molecules.<ref>{{cite encyclopedia|title= Molecule|encyclopedia=[[Encyclopædia Britannica]]|date =22 January 2016|url=http://global.britannica.com/science/molecule|access-date=23 February 2016}}</ref>}}
{{term|term= '''[[Physics:Molecular physics|Molecular physics]]'''}}{{defn|defn=Is the study of the physical properties of [[Physics:Molecule|molecule]]s, the [[Chemistry:Chemical bond|chemical bond]]s between [[Physics:Atom|atom]]s as well as the [[Physics:Molecular dynamics|molecular dynamics]].  Its most important experimental techniques are the various types of [[Physics:Spectroscopy|spectroscopy]]; [[Physics:Scattering|scattering]] is also used. The field is closely related to [[Physics:Atomic physics|atomic physics]] and overlaps greatly with [[Chemistry:Theoretical chemistry|theoretical chemistry]], [[Chemistry:Physical chemistry|physical chemistry]] and [[Physics:Chemical physics|chemical physics]].<ref>[https://www.chegg.com/homework-help/definitions/molecular-physics-204 Molecular Physics ]</ref>}}
{{term|term= '''[[Physics:Moment of inertia|Moment of inertia]]'''}}{{defn|defn=The moment of inertia, otherwise known as the '''mass moment of inertia''', '''angular mass''', '''second moment of mass''', or most accurately, '''rotational inertia''', of a [[Rigid body|rigid body]] is a quantity that determines the [[Physics:Torque|torque]] needed for a desired [[Physics:Angular acceleration|angular acceleration]] about a rotational axis, akin to how [[Physics:Mass|mass]] determines the [[Physics:Force|force]] needed for a desired [[Physics:Acceleration|acceleration]]. It depends on the body's mass distribution and the axis chosen, with larger moments requiring more torque to change the body's rate of rotation.}}
{{term|term= '''[[Physics:Multibody system|Multibody system]]'''}}{{defn|defn=Is the study of the dynamic behavior of interconnected rigid or flexible bodies, each of which may undergo large translational and rotational displacements.}}
{{term|term= '''[[Multidisciplinary design optimization]]'''}}{{defn|defn=(MDO), is a field of [[Engineering:Engineering|engineering]] that uses optimization methods to solve [[Design|design]] problems incorporating a number of disciplines. It is also known as multidisciplinary system design optimization (MSDO).

MDO allows designers to incorporate all relevant disciplines simultaneously.  The optimum of the simultaneous problem is superior to the design found by optimizing each discipline sequentially, since it can exploit the interactions between the disciplines.  However, including all disciplines simultaneously significantly increases the [[Computational complexity theory|complexity]] of the problem.}}
{{term|term= '''Mutual inductance'''}}{{defn|defn=Is the ratio between the [[Physics:Electromotive force|electromotive force]] induced in one loop or coil by the rate of change of current in another loop or coil. Mutual inductance is given the symbol M.}}
{{term|term= '''[[Physics:Muon|Muon]]'''}}{{defn|defn=The muon, from the Greek letter mu (μ) used to represent it) is an [[Physics:Elementary particle|elementary particle]] similar to the [[Physics:Electron|electron]], with an [[Physics:Electric charge|electric charge]] of &minus;1&nbsp;''e'' and a [[Physics:Spin-½|spin of]] 1/2, but with a much greater mass. It is classified as a [[Physics:Lepton|lepton]]. As with other leptons, the muon is not known to have any sub-structure – that is, it is not thought to be composed of any simpler particles.

The muon is an unstable [[Physics:Subatomic particle|subatomic particle]] with a mean lifetime of {{val|2.2|ul=µs}}, much longer than many other subatomic particles. As with the decay of the non-elementary [[Physics:Neutron|neutron]] (with a lifetime around 15 minutes), muon decay is slow (by subatomic standards) because the decay is mediated only by the [[Physics:Weak interaction|weak interaction]] (rather than the more powerful [[Physics:Strong interaction|strong interaction]] or [[Physics:Electromagnetic interaction|electromagnetic interaction]]), and because the mass difference between the muon and the set of its decay products is small, providing few kinetic [[Degrees of freedom|degrees of freedom]] for decay. Muon decay almost always produces at least three particles, which must include an [[Physics:Electron|electron]] of the same charge as the muon and two types of [[Physics:Neutrino|neutrino]]s.}}

{{glossary end}}

== N ==
{{glossary}}

{{term|term= '''[[Physics:Nanoengineering|Nanoengineering]]'''}}{{defn|defn=Is the practice of [[Engineering:Engineering|engineering]] on the [[Physics:Nanoscopic scale|nanoscale]]. It derives its name from the [[Nanometre|nanometre]], a unit of measurement equalling one billionth of a meter. Nanoengineering is largely a synonym for [[Engineering:Nanotechnology|nanotechnology]], but emphasizes the engineering rather than the pure science aspects of the field.}} 
{{term|term= '''[[Engineering:Nanotechnology|Nanotechnology]]'''}}{{defn|defn=The technology of systems built with moving parts on the order of a nanometre in size.}} 
{{term|term= '''[[Physics:Navier–Stokes equations|Navier–Stokes equations]]'''}}{{defn|defn=In [[Physics:Physics|physics]], the Navier–Stokes equations are a set of [[Partial differential equation|partial differential equation]]s which describe the motion of viscous fluid substances, named after French engineer and physicist [[Biography:Claude-Louis Navier|Claude-Louis Navier]] and Anglo-Irish physicist and mathematician [[Biography:Sir George Stokes, 1st Baronet|George Gabriel Stokes]].}}
{{term|term= '''[[Physics:Neutrino|Neutrino]]'''}}{{defn|defn=A neutrino (denoted by the Greek letter {{math|ν}}) is a [[Physics:Fermion|fermion]] (an [[Physics:Elementary particle|elementary particle]] with spin of {{sfrac|1|2}}) that interacts only via the [[Physics:Weak interaction|weak subatomic force]] and [[Physics:Gravity|gravity]].<ref>Close, Frank (2010). Neutrinos (softcover ed.). Oxford University Press. {{ISBN|978-0-199-69599-7}}.</ref><ref name="Jayawardhana"/> The neutrino is so named because it is [[Physics:Electric charge|electrically]] neutral and because its [[Physics:Rest mass|rest mass]] is so small (''-ino'') that it was long thought to be zero. The [[Physics:Mass|mass]] of the neutrino is much smaller than that of the other known elementary particles.<ref>Mertens, Susanne (2016). "Direct neutrino mass experiments". Journal of Physics: Conference Series. 718 (2): 022013. arXiv:1605.01579. Bibcode:2016JPhCS.718b2013M. doi:10.1088/1742-6596/718/2/022013. S2CID 56355240.</ref> The weak force has a very short range, the gravitational interaction is extremely weak, and neutrinos do not participate in the [[Physics:Strong interaction|strong interaction]].<ref name="NYT-20200415">{{cite news |last=Overbye |first=Dennis |title=Why The Big Bang Produced Something Rather Than Nothing - How did matter gain the edge over antimatter in the early universe? Maybe, just maybe, neutrinos. |url=https://www.nytimes.com/2020/04/15/science/physics-neutrino-antimatter-ichikawa-t2k.html |date=15 April 2020 |work={{wipe|The New York Times}} |access-date=16 April 2020 }}</ref> Thus, neutrinos typically pass through normal matter unimpeded and undetected.<ref>{{cite book |title=Neutrinos |author=Close, Frank |year=2010 |publisher=[[Organization:Oxford University Press|Oxford University Press]] |edition=softcover |isbn=978-0-199-69599-7}}</ref><ref name="Jayawardhana">{{cite book |title=The Neutrino Hunters: The chase for the ghost particle and the secrets of the universe |author=Jayawardhana, Ray |year=2015 |publisher=Oneworld Publications |edition=softcover |isbn=978-1-780-74647-0}}</ref>}}
{{term|term= '''[[Physics:Newtonian fluid|Newtonian fluid]]'''}}{{defn|defn=Is a [[Physics:Fluid|fluid]] in which the [[Physics:Viscous stress tensor|viscous stresses]] arising from its [[Physics:Fluid dynamics|flow]], at every point, are linearly<ref>{{cite book |first=Ronald L. |last=Panton |title=Incompressible Flow |edition=Fourth |year=2013 |publisher=John Wiley & Sons |location=Hoboken |page=114 |isbn=978-1-118-01343-4 }}</ref> correlated to the local [[Physics:Strain rate|strain rate]]—the rate of change of its [[Physics:Deformation (mechanics)|deformation]] over time.<ref name=Batchelor>{{cite book |first= G. K. |last=Batchelor |title= An Introduction to Fluid Dynamics |publisher= Cambridge Mathematical Library series, Cambridge University Press |year=2000 |orig-year= 1967 |url= https://books.google.com/books?id=Rla7OihRvUgC&q=An%20Introduction%20to%20Fluid%20Dynamics&pg=PP1 |isbn=978-0-521-66396-0}}</ref><ref name=Kundu>{{cite book |last1= Kundu |first1=P. |last2=Cohen |first2=I. |title= Fluid Mechanics |page= (page needed)}}</ref><ref name=Kirby>{{cite book |last= Kirby |first=B. J. |title= Micro- and Nanoscale Fluid Mechanics: Transport in Microfluidic Devices |url= http://www.kirbyresearch.com/textbook | year= 2010| publisher=Cambridge University Press |isbn=978-0-521-11903-0}}</ref> That is equivalent to saying those forces are proportional to the rates of change of the fluid's [[Physics:Velocity|velocity vector]] as one moves away from the point in question in various directions. More precisely, a fluid is Newtonian only if the [[Tensor|tensor]]s that describe the viscous stress and the strain rate are related by a constant [[Physics:Viscosity|viscosity tensor]] that does not depend on the stress state and velocity of the flow. If the fluid is also isotropic (that is, its mechanical properties are the same along any direction), the viscosity tensor reduces to two real coefficients, describing the fluid's resistance to continuous [[Physics:Shearing|shear deformation]] and continuous compression or expansion, respectively.}}
{{term|term= '''[[Engineering:Norton's theorem|Norton's theorem]]'''}}{{defn|defn=In direct-current [[Physics:Circuit theory|circuit theory]], Norton's theorem (aka ''Mayer–Norton theorem'') is a simplification that can be applied to networks made of linear time-invariant resistances, voltage sources, and current sources. At a pair of terminals of the network, it can be replaced by a current source and a single resistor in parallel. For [[Physics:Alternating current|alternating current]] (AC) systems the theorem can be applied to reactive [[Physics:Electrical impedance|impedances]] as well as resistances.}}
{{term|term= '''[[Physics:Nozzle|Nozzle]]'''}}{{defn|defn=Is a device designed to control the direction or characteristics of a [[Physics:Fluid|fluid]] flow (especially to increase velocity) as it exits (or enters) an enclosed chamber or pipe. A nozzle is often a pipe or tube of varying cross sectional area, and it can be used to direct or modify the flow of a fluid ([[Physics:Liquid|liquid]] or [[Physics:Gas|gas]]). Nozzles are frequently used to control the rate of flow, speed, direction, mass, shape, and/or the pressure of the stream that emerges from them. In a nozzle, the velocity of fluid increases at the expense of its pressure energy.}}
{{term|term= '''[[Nth root|''n''th root]]'''}}{{defn|defn=To put a number of function to the exponential power of 1/n.}} 
{{term|term= '''[[Physics:Nuclear binding energy|Nuclear binding energy]]'''}}{{defn|defn=The difference between the total mass energy of a nucleus and the mass energy of the isolated nucleons.}}
{{term|term= '''[[Engineering:Nuclear engineering|Nuclear engineering]]'''}}{{defn|defn=The profession that deals with nuclear power.}}
{{term|term= '''[[Physics:Nuclear fusion|Nuclear fusion]]'''}}{{defn|defn=Is a [[Physics:Nuclear reaction|reaction]] in which two or more atomic nuclei are combined to form one or more different atomic nuclei and subatomic particles (neutrons or protons). The difference in mass between the reactants and products is manifested as either the release or the absorption of [[Physics:Energy|energy]]. This difference in mass arises due to the difference in [[Physics:Nuclear binding energy|atomic binding energy]] between the nuclei before and after the reaction. Fusion is the process that powers active or [[Astronomy:Main sequence|main sequence]] [[Astronomy:Star|star]]s and other [[Astronomy:Absolute magnitude|high-magnitude]] stars, where large amounts of energy are [[Astronomy:Proton–proton chain reaction|released]].}}
{{term|term= '''[[Physics:Nuclear physics|Nuclear physics]]'''}}{{defn|defn=The science that describes the components of atoms.}}
{{term|term= '''Nuclear potential energy'''}}{{defn|defn=The energy that is given up in decay of an unstable nucleus.}}
{{term|term= '''[[Physics:Nuclear power|Nuclear power]]'''}}{{defn|defn=The use of energy derived from nuclear chain reactions for electricity production or ship propulsion.}}
{{glossary end}}

==O==
{{glossary}}

{{term|term= '''[[Ohm]]'''}}{{defn|defn=The SI unit of electrical resistance.}} 
{{term|term= '''[[Physics:Ohm's law|Ohm's law]]'''}}{{defn|defn=A law describing the relationship between resistance, current, and voltage.}} 
{{term|term= '''[[Physics:Optics|Optics]]'''}}{{defn|defn= The study of light.}}
{{term|term= '''[[Chemistry:Organic chemistry|Organic chemistry]]'''}}{{defn|defn= The study of carbon compounds.}}
{{term|term= '''[[Physics:Osmosis|Osmosis]]'''}}{{defn|defn=The spontaneous movement of molecules or ions through a semi-permable membrane, tending to equalize concentration on both sides.}}
{{glossary end}}

==P==
{{glossary}}

{{term|term= '''Parallel circuit'''}}{{defn|defn=A circuit that begins and ends at the same node as another circuit.}} 
{{term|term= '''[[Parity (mathematics)]]'''}}{{defn|defn=In [[Mathematics|mathematics]], parity is the property of an [[Integer|integer]] of whether it is even or odd. An integer's parity is even if it is divisible by two with no remainders left and its parity is odd if its remainder is 1.<ref name="rod">{{citation|title=Figuring Out Mathematics|last1=Vijaya|first1=A.V.|last2=Rodriguez|first2=Dora |publisher=Pearson Education India|isbn=9788131703571|pages=20–21|url=https://books.google.com/books?id=9ZN9LuHb0tQC&pg=PA20}}.</ref> For example, -4, 0, 82, and 178 are even because there is no [[Remainder|remainder]] when dividing it by 2. By contrast, -3, 5, 7, 21 are odd numbers as they leave a remainder of 1 when divided by 2.}}
{{term|term= '''[[Physics:Parity|Parity]]'''}}{{defn|defn=In [[Physics:Quantum mechanics|quantum mechanics]], a parity transformation (also called parity inversion) is the flip in the sign of ''one'' [[Three-dimensional space|spatial]] coordinate. In three dimensions, it can also refer to the simultaneous flip in the sign of all three spatial coordinates (a [[Point reflection|point reflection]]):

:<math>\mathbf{P}: \begin{pmatrix}x\\y\\z\end{pmatrix} \mapsto \begin{pmatrix}-x\\-y\\-z\end{pmatrix}.</math>

It can also be thought of as a test for [[Physics:Chirality|chirality]] of a physical phenomenon, in that a parity inversion transforms a phenomenon into its mirror image. All fundamental interactions of [[Physics:Elementary particle|elementary particle]]s, with the exception of the [[Physics:Weak interaction|weak interaction]], are symmetric under parity. The weak interaction is chiral and thus provides a means for probing chirality in physics. In interactions that are symmetric under parity, such as electromagnetism in atomic and molecular physics, parity serves as a powerful controlling principle underlying quantum transitions.

A matrix representation of '''P''' (in any number of dimensions) has [[Determinant|determinant]] equal to −1, and hence is distinct from a [[Physics:Rotation|rotation]], which has a determinant equal to 1. In a two-dimensional plane, a simultaneous flip of all coordinates in sign is ''not'' a parity transformation; it is the same as a 180°-[[Physics:Rotation|rotation]].

In [[Physics:Quantum mechanics|quantum mechanics]], wave functions that are unchanged by a parity transformation are described as [[Even and odd functions|even]] functions, while those that change sign under a parity transformation are odd functions.fn=A hydrocarbon compound, solid at room temperature.}} 
{{term|term= '''[[Physics:Paramagnetism|Paramagnetism]]'''}}{{defn|defn=Is a form of [[Physics:Magnetism|magnetism]] whereby some materials are weakly attracted by an externally applied [[Physics:Magnetic field|magnetic field]], and form internal, [[Physics:Magnetization|induced magnetic field]]s in the direction of the applied magnetic field. In contrast with this behavior, [[Physics:Diamagnetism|diamagnetic]] materials are repelled by magnetic fields and form induced magnetic fields in the direction opposite to that of the applied magnetic field.<ref>Miessler, G. L. and Tarr, D. A. (2010) ''Inorganic Chemistry'' 3rd ed., Pearson/Prentice Hall publisher, {{ISBN|0-13-035471-6}}.</ref> Paramagnetic materials include most [[Chemistry:Chemical element|chemical element]]s and some compounds;<ref>[https://global.britannica.com/science/paramagnetism britannica.com]</ref> they have a relative magnetic permeability slightly greater than 1 (i.e., a small positive [[Physics:Magnetic susceptibility|magnetic susceptibility]]) and hence are attracted to magnetic fields. The [[Physics:Magnetic moment|magnetic moment]] induced by the applied field is linear in the field strength and rather weak. It typically requires a sensitive analytical balance to detect the effect and modern measurements on paramagnetic materials are often conducted with a [[Physics:SQUID|SQUID]] [[Physics:Magnetometer|magnetometer]].}}
{{term|term= '''[[Physics:Particle accelerator|Particle accelerator]]'''}}{{defn|defn=Is a machine that uses [[Physics:Electromagnetic field|electromagnetic field]]s to propel [[Physics:Electric charge|charged]] [[Physics:Particle|particle]]s to very high speeds and energies, and to contain them in well-defined [[Physics:Particle beam|beams]].<ref>{{Cite book 
 |last2=Blewett |first2=J.
 |year=1969 
 |title=Particle Accelerators
 |publisher=McGraw-Hill
 |location=New York
 |isbn=978-1-114-44384-6
}}</ref>}}
{{term|term= '''[[Physics:Particle displacement|Particle displacement]]'''}}{{defn|defn=Particle displacement or displacement amplitude is a [[Measurement|measurement]] of [[Distance|distance]] of the movement of a [[Physics:Sound particle|sound particle]] from its [[Physics:Mechanical equilibrium|equilibrium]] position in a medium as it transmits a sound wave.<ref>
{{cite book
 | title = Microsensors, MEMS, and Smart Devices John 2 | year = 2001
 | isbn = 978-0-471-86109-6
 | pages = 23–322
 | url = https://books.google.com/books?id=ht69jE9ypSwC&pg=PA321
 | last1 = Gardner
 | first1 = Julian W.
 | last2 = Varadan
 | first2 = Vijay K.
 | last3 = Awadelkarim
 | first3 = Osama O.
 }}</ref> 
The [[International System of Units|SI unit]] of particle displacement is the [[Metre|metre]] (m). In most cases this is a [[Physics:Longitudinal wave|longitudinal wave]] of pressure (such as [[Physics:Sound|sound]]), but it can also be a [[Physics:Transverse wave|transverse wave]], such as the [[Oscillation|vibration]] of a taut string. In the case of a [[Physics:Sound wave|sound wave]] travelling through air, the particle displacement is evident in the [[Oscillation|oscillation]]s of air [[Physics:Molecule|molecule]]s with, and against, the direction in which the sound wave is travelling.<ref>{{cite book
 | author= Arthur Schuster
 | title=An Introduction to the Theory of Optics
 | publisher=London: Edward Arnold
 | year=1904
 | url = https://archive.org/details/bub_gb_Zb4KAAAAIAAJ
 | quote= An Introduction to the Theory of Optics By Arthur Schuster.
 }}</ref>}}
{{term|term= '''[[Physics:Particle physics|Particle physics]]'''}}{{defn|defn=Particle physics (also known as ''high energy physics'') is a branch of [[Physics:Physics|physics]] that studies the nature of the particles that constitute [[Physics:Matter|matter]] and [[Physics:Radiation|radiation]]. Although the word ''[[Physics:Particle|particle]]'' can refer to various types of very small objects (e.g. protons, gas particles, or even household dust), {{em|particle physics}} usually investigates the irreducibly smallest detectable particles and the [[Physics:Fundamental interaction|fundamental interaction]]s necessary to explain their behaviour. In current understanding, these [[Physics:Elementary particle|elementary particle]]s are excitations of the [[Physics:Field#Quantum fields|quantum fields]] that also govern their interactions. The currently dominant theory explaining these fundamental particles and fields, along with their dynamics, is called the [[Physics:Standard Model|Standard Model]]. Thus, modern particle physics generally investigates the Standard Model and its various possible extensions, e.g. to the newest "known" particle, the [[Physics:Higgs boson|Higgs boson]], or even to the oldest known force field, [[Physics:Gravity|gravity]].<ref>{{cite web|url=http://home.web.cern.ch/topics/higgs-boson|title=The Higgs Boson |publisher=CERN}}</ref><ref>{{cite web | url=https://www.nobelprize.org/nobel_prizes/physics/laureates/2013/advanced-physicsprize2013.pdf | title=The BEH-Mechanism, Interactions with Short Range Forces and Scalar Particles | date=8 October 2013}}</ref>}}
{{term|term= '''[[Physics:Pascal's law|Pascal's law]]'''}}{{defn|defn=Pascal's law (also ''Pascal's principle''<ref>{{cite web|url=http://www.britannica.com/EBchecked/topic/445445/Pascals-principle|title=Pascal's principle - Definition, Example, & Facts|website=britannica.com|access-date=9 May 2018|url-status=live|archive-url=https://web.archive.org/web/20150602231705/http://www.britannica.com/EBchecked/topic/445445/Pascals-principle|archive-date=2 June 2015}}</ref><ref>{{cite web|url=https://www.grc.nasa.gov/www/k-12/WindTunnel/Activities/Pascals_principle.html|title=Pascal's Principle and Hydraulics|website=www.grc.nasa.gov|access-date=9 May 2018|url-status=dead|archive-url=https://web.archive.org/web/20180405051915/https://www.grc.nasa.gov/www/k-12/WindTunnel/Activities/Pascals_principle.html|archive-date=5 April 2018}}</ref><ref>{{cite web|url=http://hyperphysics.phy-astr.gsu.edu/hbase/pasc.html|title=Pressure|website=hyperphysics.phy-astr.gsu.edu|access-date=9 May 2018|url-status=live|archive-url=https://web.archive.org/web/20171028014050/http://hyperphysics.phy-astr.gsu.edu/hbase/pasc.html|archive-date=28 October 2017}}</ref> or the ''principle of transmission of fluid-pressure'') is a principle in [[Physics:Fluid mechanics|fluid mechanics]] that states that a pressure change occurring anywhere in a confined incompressible fluid is transmitted throughout the fluid such that the same change occurs everywhere.<ref>{{cite book
 | last = Bloomfield
 | first = Louis
 | title = How Things Work: The Physics of Everyday Life
 | url = https://archive.org/details/howthingsworkphy00bloo_760
 | url-access = limited
 | publisher = {{wipe|John Wiley & Sons}}
 | year = 2006
 | page = [https://archive.org/details/howthingsworkphy00bloo_760/page/n168 153]
 | isbn = 978-0-471-46886-8 | edition = Third
 }}</ref> The law was established by French [[Biography:Mathematician|mathematician]] [[Biography:Blaise Pascal|Blaise Pascal]]<ref name=acottLaw>{{Cite journal |author=Acott, Chris |title=The diving "Law-ers": A brief resume of their lives |journal=South Pacific Underwater Medicine Society Journal |volume=29 |issue=1 |year=1999 |issn=0813-1988 |oclc=16986801 |url=http://archive.rubicon-foundation.org/5990 |access-date=2011-06-14 |url-status=live |archive-url=https://web.archive.org/web/20110402073203/http://archive.rubicon-foundation.org/5990 |archive-date=2011-04-02 }}.</ref> in 1647–48.<ref>{{cite web |last1=O'Connor |first1=J.J. |last2=Robertson |first2=E.F. |author-link2=Edmund F. Robertson |title=Étienne Pascal |url=http://www-history.mcs.st-andrews.ac.uk/Biographies/Pascal_Etienne.html |date=August 2006 |publisher=[[Organization:University of St Andrews|University of St. Andrews, Scotland]] |access-date=5 February 2010 |url-status=live |archive-url=https://web.archive.org/web/20100419181846/http://www-history.mcs.st-andrews.ac.uk/Biographies/Pascal_Etienne.html |archive-date=19 April 2010 }}</ref>}}
{{term|term= '''[[Physics:Pendulum|Pendulum]]'''}}{{defn|defn=Is a weight suspended from a pivot so that it can swing freely.<ref>{{cite encyclopedia
 | title = Pendulum
 | encyclopedia = Miriam Webster's Collegiate Encyclopedia
 | page = 1241
 | publisher = Miriam Webster
 | year = 2000
 | isbn = 978-0-87779-017-4
  }}</ref> When a pendulum is displaced sideways from its resting, [[Physics:Mechanical equilibrium|equilibrium position]], it is subject to a [[Physics:Restoring force|restoring force]] due to [[Physics:Gravity|gravity]] that will accelerate it back toward the equilibrium position. When released, the restoring force acting on the pendulum's mass causes it to oscillate about the equilibrium position, swinging back and forth. The time for one complete cycle, a left swing and a right swing, is called the [[Physics:Frequency|period]]. The period depends on the length of the pendulum and also to a slight degree on the [[Physics:Amplitude|amplitude]], the width of the pendulum's swing.}}
{{term|term= '''[[Engineering:Petroleum engineering|Petroleum engineering]]'''}}{{defn|defn=Is a field of engineering concerned with the activities related to the production of Hydrocarbons, which can be either crude oil or [[Chemistry:Natural gas|natural gas]].<ref name="pet eng 2">{{Cite web|url=https://www.bls.gov/ooh/architecture-and-engineering/petroleum-engineers.htm#tab-2|title=Petroleum Engineers: Occupational Outlook Handbook: U.S. Bureau of Labor Statistics|website=www.bls.gov|access-date=2018-02-06}}</ref> Exploration and production are deemed to fall within the ''upstream'' sector of the oil and gas industry. [[Chemistry:Hydrocarbon exploration|Exploration]], by [[Earth:Earth science|earth scientists]], and petroleum engineering are the oil and gas industry's two main subsurface disciplines, which focus on maximizing economic recovery of hydrocarbons from subsurface reservoirs. [[Earth:Petroleum geology|Petroleum geology]] and [[Physics:Geophysics|geophysics]] focus on provision of a static description of the hydrocarbon reservoir rock, while petroleum engineering focuses on estimation of the recoverable volume of this resource using a detailed understanding of the physical behavior of oil, water and gas within porous rock at very high pressure.}}
{{term|term= '''[[Chemistry:PH|pH]]'''}}{{defn|defn=A logarithmic measure of the concentration of  hydrogen ions in an acid or base solution.}} 
{{term|term= '''[[Physics:Phase (matter)|Phase (matter)]]'''}}{{defn|defn=In the [[Physics:Outline of physical science|physical sciences]], a phase is a region of space (a [[Physics:Thermodynamic system|thermodynamic system]]), throughout which all physical properties of a material are essentially uniform.<ref>{{cite book|last=Modell|first=Michael|author2=Robert C. Reid|title=Thermodynamics and Its Applications|publisher=Prentice-Hall|location=Englewood Cliffs, NJ|date=1974|isbn=978-0-13-914861-3|url-access=registration|url=https://archive.org/details/thermodynamicsit00mode}}</ref><ref name="Fermi2012">{{cite book|author=Enrico Fermi|title=Thermodynamics|date=25 April 2012|publisher=Courier Corporation|isbn=978-0-486-13485-7}}</ref>{{rp|86}}<ref name="Adkins1983">{{cite book|author=Clement John Adkins|title=Equilibrium Thermodynamics|date=14 July 1983|publisher=Cambridge University Press|isbn=978-0-521-27456-2}}</ref>{{rp|3}} Examples of physical properties include [[Physics:Density|density]], [[Physics:Refractive index|index of refraction]], [[Physics:Magnetization|magnetization]] and chemical composition. A simple description is that a phase is a region of material that is chemically uniform, physically distinct, and (often) mechanically separable. In a system consisting of ice and water in a glass jar, the ice cubes are one phase, the water is a second phase, and the humid air is a third phase over the ice and water. The glass of the jar is another separate phase. (See {{section link|state of matter|Glass}})}}
{{term|term= '''[[Physics:Phase (waves)|Phase (waves)]]'''}}{{defn|defn=In [[Physics:Physics|physics]] and [[Mathematics|mathematics]], the phase of a [[Periodic function|periodic function]] <math>F</math> of some [[Real number|real]] variable <math>t</math> (such as time) is an [[Angle|angle]]-like quantity representing the fraction of the cycle covered up to <math>t</math>.  It is denoted <math>\phi(t)</math> and expressed in such a scale that it varies by one full [[Turn (geometry)|turn]] as the variable <math>t</math> goes through each period (and <math>F(t)</math> goes through each complete cycle).  It may be [[Measure (mathematics)|measured]] in any [[Angular unit|angular unit]] such as [[Degree (angle)|degrees]] or radians, thus increasing by 360° or <math>2\pi</math> as the variable <math>t</math> completes a full period.<ref name=Ballou2005>{{cite book |last=Ballou |first=Glen |title=Handbook for sound engineers |url=https://books.google.com/books?id=y0d9VA0lkogC&pg=PA1499 |edition=3 |year=2005 |publisher=Focal Press, Gulf Professional Publishing |isbn=978-0-240-80758-4 |page=1499}}</ref>}}
{{term|term= '''[[Phase diagram]]'''}}{{defn|defn=A phase diagram in [[Chemistry:Physical chemistry|physical chemistry]], [[Engineering:Engineering|engineering]], [[Earth:Mineralogy|mineralogy]], and [[Physics:Materials science|materials science]] is a type of [[Chart|chart]] used to show conditions (pressure, temperature, volume, etc.) at which thermodynamically distinct [[Physics:Phase (matter)|phases]] (such as solid, liquid or gaseous states) occur and coexist at [[Physics:Thermodynamic equilibrium|equilibrium]].}} 
{{term|term= '''[[Physics:Phase rule|Phase rule]]'''}}{{defn|defn=In [[Physics:Thermodynamics|thermodynamics]], the phase rule is a general principle governing "pVT" systems (that is, systems whose [[Physics:Thermodynamic state|states]] are completely described by the variables [[Physics:Pressure|pressure]] ({{mvar|p}}), [[Physics:Volume|volume]] ({{mvar|V}}) and [[Physics:Temperature|temperature]] ({{mvar|T}})) in [[Physics:Thermodynamic equilibrium|thermodynamic equilibrium]]. If {{mvar|F}} is the number of [[Chemistry:Degrees of freedom (physics and chemistry)|degrees of freedom]], {{mvar|C}} is the number of [[Chemistry:Component (thermodynamics)|components]] and {{mvar|P}} is the number of [[Physics:Phase (matter)|phases]], then<ref>{{Cite book|last=Smith|first=Joe Mauk|title=Introduction to chemical engineering thermodynamics|publisher=McGraw-Hill Education|year=2018|isbn=978-1-259-69652-7|location=United States of America|pages=422}}</ref><ref name="Atkins"/> 
:<math>F = C - P + 2.</math>
It was derived by American physicist [[Biography:Josiah Willard Gibbs|Josiah Willard Gibbs]] in his landmark paper titled ''[[Physics:On the Equilibrium of Heterogeneous Substances|On the Equilibrium of Heterogeneous Substances]]'', published in parts between 1875 and 1878.<ref>{{citation|first=J. W.|last=Gibbs|title=Scientific Papers |location=Dover, New York|year=1961}}</ref>
The rule assumes the components do not [[Chemistry:Chemical reaction|react]] with each other.}}
{{term|term= '''[[Physics:Photon|Photon]]'''}}{{defn|defn=Is a type of [[Physics:Elementary particle|elementary particle]]. It is the [[Physics:Quantum|quantum]] of the [[Physics:Electromagnetic field|electromagnetic field]] including [[Physics:Electromagnetic radiation|electromagnetic radiation]] such as [[Physics:Light|light]] and [[Radio wave|radio wave]]s, and the [[Physics:Force carrier|force carrier]] for the [[Physics:Electromagnetic force|electromagnetic force]]. Photons are [[Physics:Massless particle|massless]],{{efn|The photon's [[Physics:Invariant mass|invariant mass]] (also called "rest mass" for massive particles) is believed to be exactly zero.  This is the notion of particle mass generally used by modern physicists.  The photon does have a nonzero [[Physics:Relativistic mass|relativistic mass]], depending on its energy, but this varies according to the [[Astronomy:Frame of reference|frame of reference]].}} so they always move at the [[Physics:Speed of light|speed of light in vacuum]], {{val|299792458|u=m/s}} (or about {{convert|299792458|m/s|mi/s|disp=out|sigfig=6}}). The photon belongs to the class of bosons.}}
{{term|term= '''[[Chemistry:Physical chemistry|Physical chemistry]]'''}}{{defn|defn=Is the study of [[Physics:Macroscopic scale|macroscopic]], and particulate phenomena in [[Chemistry:Chemistry|chemical]] systems in terms of the principles, practices, and concepts of [[Physics:Physics|physics]] such as [[Physics:Motion|motion]], [[Physics:Energy|energy]], [[Physics:Force|force]], [[Time|time]], [[Physics:Thermodynamics|thermodynamics]], [[Chemistry:Quantum chemistry|quantum chemistry]], [[Physics:Statistical mechanics|statistical mechanics]], [[Physics:Analytical dynamics|analytical dynamics]] and [[Chemistry:Chemical equilibrium|chemical equilibrium]].}}
{{term|term= '''[[Physics:Physical quantity|Physical quantity]]'''}}{{defn|defn=A physical quantity is a property of a material or system that can be [[Philosophy:Quantification (science)|quantified]] by [[Measurement|measurement]]. A physical quantity can be expressed as a ''value'', which is the algebraic multiplication of a ''numerical value'' and a [[Unit of measurement|''unit'']]. For example, the physical quantity [[Physics:Mass|mass]] can be quantified as ''n'' [[Kilogram|kg]], where ''n'' is the numerical value and kg is the unit. A physical quantity possesses at least two characteristics in common. One is numerical magnitude and the other is the unit in which it is measured.}}
{{term|term= '''[[Physics:Physics|Physics]]'''}}{{defn|defn=Is the [[Natural science|natural science]] that studies [[Physics:Matter|matter]],{{efn|At the start of ''[[Physics:The Feynman Lectures on Physics|The Feynman Lectures on Physics]]'', [[Biography:Richard Feynman|Richard Feynman]] offers the [[Physics:Atomic theory|atomic hypothesis]] as the single most prolific scientific concept.<ref name="feynmanleightonsands1963-atomic">{{harvnb|Feynman|Leighton|Sands|1963|p=I-2}} "If, in some cataclysm, all [] scientific knowledge were to be destroyed [save] one sentence&nbsp;[...] what statement would contain the most information in the fewest words? I believe it is&nbsp;[...] that ''all things are made up of atoms&nbsp;– little particles that move around in perpetual motion, attracting each other when they are a little distance apart, but repelling upon being squeezed into one another''&nbsp;..."</ref> }} its [[Physics:Motion|motion]] and behavior through [[Physics:Spacetime|space and time]], and the related entities of [[Physics:Energy|energy]] and [[Physics:Force|force]].<ref name="maxwell1878-physicalscience">{{harvnb|Maxwell|1878|p=9}} "Physical science is that department of knowledge which relates to the order of nature, or, in other words, to the regular succession of events."</ref> Physics is one of the most fundamental [[Science|scientific]] disciplines, and its main goal is to understand how the [[Astronomy:Universe|universe]] behaves.{{efn|The term "universe" is defined as everything that physically exists: the entirety of space and time, all forms of matter, energy and momentum, and the physical laws and constants that govern them. However, the term "universe" may also be used in slightly different contextual senses, denoting concepts such as the [[Astronomy:Cosmos|cosmos]] or the philosophical world.}}<ref name="youngfreedman2014p1">{{harvnb |Young|Freedman|2014|p=1}} "Physics is one of the most fundamental of the sciences. Scientists of all disciplines use the ideas of physics, including chemists who study the structure of molecules, paleontologists who try to reconstruct how dinosaurs walked, and climatologists who study how human activities affect the atmosphere and oceans. Physics is also the foundation of all engineering and technology. No engineer could design a flat-screen TV, an interplanetary spacecraft, or even a better mousetrap without first understanding the basic laws of physics. (...) You will come to see physics as a towering achievement of the human intellect in its quest to understand our world and ourselves."</ref><ref name="youngfreedman2014p2">{{harvnb |Young|Freedman|2014|p=2}} "Physics is an experimental science. Physicists observe the phenomena of nature and try to find patterns that relate these phenomena."</ref><ref name="holzner2003-physics">{{harvnb|Holzner|2006|p=7}} "Physics is the study of your world and the world and universe around you."</ref>}}
{{term|term= '''[[Physics:Planck constant|Planck constant]]'''}}{{defn|defn=The Planck constant, or '''Planck's constant''', is a fundamental [[Physics:Physical constant|physical constant]] denoted <math>h</math>, and is of fundamental importance in [[Physics:Quantum mechanics|quantum mechanics]]. A [[Physics:Photon|photon]]'s energy is equal to its frequency multiplied by the Planck constant.  Due to [[Mass–energy equivalence|mass–energy equivalence]], the Planck constant also relates mass to frequency.

In [[Metrology|metrology]] it is used, together with other constants, to define the [[Kilogram|kilogram]], an SI unit.<ref>{{SIbrochure9th|page=131}}</ref> The SI units are defined in such a way that, when the Planck constant is expressed in SI units, it has the exact value {{nowrap|<math>h</math> {{=}} {{physconst|h|after=.}}}}<ref>{{cite web|url=https://www.bipm.org/utils/common/pdf/CGPM-2018/26th-CGPM-Resolutions.pdf|date=2018-11-16|work=BIPM|access-date=2018-11-20|language=en-GB|title=Resolutions of the 26th CGPM|archive-url=https://web.archive.org/web/20181119214326/https://www.bipm.org/utils/common/pdf/CGPM-2018/26th-CGPM-Resolutions.pdf|archive-date=2018-11-19|url-status=dead}}</ref>}}
{{term|term= '''[[Physics:Plasma|Plasma]]'''}}{{defn|defn=Is one of the [[Physics:State of matter#Four fundamental states|four fundamental states of matter]], first systematically studied by [[Biography:Irving Langmuir|Irving Langmuir]] in the 1920s.<ref name=Itpp1995>{{cite book |last1=Goldston |first1=R.J. |last2=Rutherford |first2=P.H. |date=1995 |title=Introduction to Plasma Physics |page=1−2 |publisher=Taylor & Francis |isbn=978-0-7503-0183-1 |url=https://books.google.com/books?id=7kM7yEFUGnAC&q=chen+%22introduction+to+plasma+physics%22}}</ref><ref name=Itpd2012a>{{cite book |last1=Morozov |first1=A.I.|date=2012 |title=Introduction to Plasma Dynamics |page=17 |publisher=CRC Press| isbn=978-1-4398-8132-3 |url=https://books.google.com/books?id=DB0L6P3TwiYC&q=Introduction+to+Plasma+Dynamics+morozov}}</ref> It consists of a gas of [[Physics:Ion|ion]]s – atoms or molecules which have one or more orbital electrons stripped (or, rarely, an extra electron attached), and free [[Physics:Electron|electron]]s.}}
{{term|term= '''[[Physics:Plasticity|Plasticity]]'''}}{{defn|defn=In [[Physics:Physics|physics]] and [[Physics:Materials science|materials science]], plasticity, also known as '''plastic deformation''', is the ability of a [[Physics:Solid|solid]] [[Physics:Material|material]] to undergo permanent [[Engineering:Deformation (engineering)|deformation]], a non-reversible change of shape in response to applied forces.<ref name="Lubliner">{{cite book |first=J. |last=Lubliner |year=2008 |title=Plasticity theory |publisher=Dover |isbn=978-0-486-46290-5 }}</ref><ref>{{cite book |last=Bigoni |first=D. |title=Nonlinear Solid Mechanics: Bifurcation Theory and Material Instability |publisher=Cambridge University Press |year=2012 |isbn=978-1-107-02541-7 }}</ref>  For example, a solid piece of metal being bent or pounded into a new shape displays plasticity as permanent changes occur within the material itself. In engineering, the transition from [[Physics:Elasticity|elastic]] behavior to plastic behavior is known as [[Engineering:Yield (engineering)|yielding]].}}
{{term|term= '''[[Engineering:Pneumatics|Pneumatics]]'''}}{{defn|defn= The control of mechanical force and movement, generated by the application of compressed gas.}}
{{term|term= '''[[Point estimation]]'''}}{{defn|defn=In [[Statistics|statistics]], point estimation involves the use of sample [[Data|data]] to calculate a single value (known as a '''point estimate''' since it identifies a [[Point (geometry)|point]] in some [[Parameter space|parameter space]]) which is to serve as a "best guess" or "best estimate" of an unknown population [[Parameter|parameter]] (for example, the population mean). More formally, it is the application of a point [[Estimator|estimator]] to the data to obtain a point estimate.

Point estimation can be contrasted with [[Interval estimation|interval estimation]]: such interval estimates are typically either [[Confidence interval|confidence interval]]s, in the case of [[Frequentist inference|frequentist inference]], or credible intervals, in the case of [[Bayesian inference]]. More generally, a point estimator can be contrasted with a set estimator. Examples are given by [[Confidence region|confidence sets]] or [[Credible interval|credible sets.]] A point estimator can also be contrasted with a distribution estimator. Examples are given by [[Confidence distribution|confidence distributions]], [[Randomised decision rule|randomized estimators]], and [[Bayesian statistics|Bayesian posteriors]].}} 
{{term|term= '''Polyphase system'''}}{{defn|defn=An electrical system that uses a set of alternating currents at different phases.}} 
{{term|term= '''[[Physics:Electric power|Power (electric)]]'''}}{{defn|defn=Electric power is the rate, per unit time, at which [[Physics:Electrical energy|electrical energy]] is transferred by an electric circuit. The SI unit of [[Physics:Power|power]] is the [[Watt|watt]], one [[Joule|joule]] per [[Second|second]].

Electric power is usually produced by [[Engineering:Electric generator|electric generator]]s, but can also be supplied by sources such as [[Physics:Battery (electricity)|electric batteries]].  It is usually supplied to businesses and homes (as domestic [[Physics:Mains electricity|mains electricity]]) by the [[Physics:Electric power industry|electric power industry]] through an electric power grid. 

Electric power can be delivered over long distances by [[Finance:Electric power transmission|transmission lines]] and used for applications such as [[Physics:Electric motor|motion]], [[Earth:Electric light|light]] or heat with high [[Engineering:Electrical efficiency|efficiency]].<ref name="smith-2001">
{{cite book | last = Smith | first = Clare | title = Environmental Physics | date = 2001 | publisher = [[Company:Routledge|Routledge]] | location = London | isbn = 0-415-20191-8}}</ref>}}
{{term|term= '''[[Physics:Power|Power]]'''}}{{defn|defn=In physics, power is the amount of [[Physics:Energy|energy]] transferred or converted per unit time. In the [[International System of Units]], the unit of power is the [[Watt|watt]], equal to one [[Joule|joule]] per second. In older works, power is sometimes called ''activity''.<ref name="Smithsonian Tables">{{cite book|title=Smithsonian Physical Tables|publisher=Smithsonian Institution|date=1921|editor-first1=Frederick E.|editor-last1=Fowle|edition=7th revised|location=Washington, D.C.|url=https://www.google.com/books/edition/Smithsonian_Physical_Tables/tCoJAQAAIAAJ?hl=en&gbpv=1&bsq=%22Power%20or%20Activity%20is%20the%20time%20rate%20of%20doing%20work%22|oclc=1142734534|archive-url=https://web.archive.org/web/20200423151426/https://www.google.com/books/edition/Smithsonian_Physical_Tables/tCoJAQAAIAAJ?hl=en&gbpv=1&bsq=%22Power%20or%20Activity%20is%20the%20time%20rate%20of%20doing%20work%22|archive-date=23 April 2020|url-status=live|quote='''Power or Activity''' is the time rate of doing work, or if {{math|''W''}} represents work and {{math|''P''}} power, {{math|''P'' {{=}} ''dw/dt''}}. (p. xxviii) ... ACTIVITY. Power or rate of doing work; unit, the watt. (p. 435)}}</ref><ref name="Heron Motors">{{cite journal|last1=Heron|first1=C. A.|date=1906|title=Electrical Calculations for Rallway Motors|url=https://www.google.com/books/edition/The_Purdue_Engineering_Review/b5A4AQAAMAAJ?hl=en&gbpv=1&dq=%22The+activity+of+a+motor+is+the+work+done+per+second%22+%22Where+the+joule+is+employed+as+the+unit+of+work,+the+international+unit+of+activity+is+the+joule-per-second,+or,+as+it+is+commonly+called,+the+watt.%22&pg=PA78&printsec=frontcover|journal=Purdue Eng. Rev.|issue=2|pages=77–93|access-date=23 April 2020|archive-url=https://web.archive.org/web/20200423142933/https://www.google.com/books/edition/The_Purdue_Engineering_Review/b5A4AQAAMAAJ?hl=en&gbpv=1&dq=%22The+activity+of+a+motor+is+the+work+done+per+second%22+%22Where+the+joule+is+employed+as+the+unit+of+work,+the+international+unit+of+activity+is+the+joule-per-second,+or,+as+it+is+commonly+called,+the+watt.%22&pg=PA78&printsec=frontcover|archive-date=23 April 2020|url-status=live|quote=The activity of a motor is the work done per second, ... Where the joule is employed as the unit of work, the international unit of activity is the joule-per-second, or, as it is commonly called, the watt. (p. 78)}}</ref><ref name="Nature 1902">{{cite journal|date=1902|title=Societies and Academies|journal=Nature|volume=66|issue=1700|pages=118–120|doi=10.1038/066118b0|quote=If the watt is assumed as unit of activity...|doi-access=free}}</ref> Power is a [[Physics:Scalar|scalar]] quantity.}} 
{{term|term= '''[[Engineering:Power factor|Power factor]]'''}}{{defn|defn=In [[Electrical engineering|electrical engineering]], the power factor of an [[Physics:AC power|AC power]] system is defined as the [[Ratio|ratio]] of the ''real power'' absorbed by the [[Engineering:Electrical load|load]] to the ''apparent power'' flowing in the circuit, and is a dimensionless number in the closed interval of −1 to 1. A power factor of less than one indicates the voltage and current are not in phase, reducing the average [[Product (mathematics)|product]] of the two. Real power is the instantaneous product of voltage and current and represents the capacity of the electricity for performing work. Apparent power is the product of [[Root mean square|RMS]] current and voltage. Due to energy stored in the load and returned to the source, or due to a non-linear load that distorts the wave shape of the current drawn from the source, the apparent power may be greater than the real power. A negative power factor occurs when the device (which is normally the load) generates power, which then flows back towards the source.}} 
{{term|term= '''[[Physics:Pressure|Pressure]]'''}}{{defn|defn=Pressure (symbol: ''p'' or ''P'') is the [[Physics:Force|force]] applied perpendicular to the surface of an object per unit [[Area|area]] over which that force is distributed.{{rp|445}}<ref>{{cite book |last1=Knight, PhD |first1=Randall D. |title=Physics for Scientists and Engineers: A Strategic Approach |date=2007 |publisher=Pearson Addison Wesley |location=San Francisco |isbn=978-0-321-51671-8 |pages=1183 |edition=2nd |url=https://books.google.com/books?id=32yzygAACAAJ&q=Physics+for+Scientists+and+Engineers:+A+Strategic+Approach |access-date=6 April 2020 |language=en-us |format=google books |chapter=Fluid Mechanics |quote={{small|''Pressure itself is not a Force, even though we sometimes talk "informally" about the "force exerted by the pressure. The correct statement is that the Fluid exerts a force on a surface. In addition, Pressure is a scalar, not a vector.'' }}}}</ref> Gauge pressure (also spelled ''gage'' pressure)<ref group=lower-alpha>The preferred spelling varies by country and even by industry. Further, both spellings are often used ''within'' a particular industry or country. Industries in British English-speaking countries typically use the "gauge" spelling.</ref> is the pressure relative to the ambient pressure.

Various units are used to express pressure. Some of these derive from a unit of force divided by a unit of area; the [[International System of Units|SI]] unit of pressure, the [[Pascal (unit)|pascal]] (Pa), for example, is one [[Newton (unit)|newton]] per [[Square metre|square metre]] (N/m<sup>2</sup>); similarly, the [[Pound (force)|pound-force]] per [[Square inch|square inch]] ([[Pounds per square inch|psi]]) is the traditional unit of pressure in the [[Imperial units|imperial]] and U.S. customary systems. Pressure may also be expressed in terms of standard atmospheric pressure; the [[Physics:Atmosphere (unit)|atmosphere]] (atm) is equal to this pressure, and the [[Torr|torr]] is defined as {{frac|760}} of this. Manometric units such as the [[Physics:Centimetre of water|centimetre of water]], [[Physics:Millimetre of mercury|millimetre of mercury]], and [[Inch of mercury|inch of mercury]] are used to express pressures in terms of the height of [[Physics:Pressure measurement#Liquid column (manometer)|column of a particular fluid]] in a manometer.}} 
{{term|term= '''[[Probability]]'''}}{{defn|defn=Is the branch of [[Mathematics|mathematics]] concerning numerical descriptions of how likely an [[Event (probability theory)|event]] is to occur, or how likely it is that a proposition is true.  The probability of an event is a number between 0 and 1, where, roughly speaking, 0 indicates impossibility of the event and 1 indicates certainty.{{NoteTag|Strictly speaking, a probability of 0 indicates that an event [[Almost surely|''almost'' never]] takes place, whereas a probability of 1 indicates than an event [[Almost surely|''almost'' certainly]] takes place. This is an important distinction when the [[Sample space|sample space]] is infinite. For example, for the [[Continuous uniform distribution|continuous uniform distribution]] on the [[Real number|real]] interval [5, 10], there are an infinite number of possible outcomes, and the probability of any given outcome being observed — for instance, exactly 7 — is 0. This means that when we make an observation, it will ''almost surely not'' be exactly 7. However, it does '''not''' mean that exactly 7 is ''impossible''. Ultimately some specific outcome (with probability 0) will be observed, and one possibility for that specific outcome is exactly 7.}}<ref name="Stuart and Ord 2009">"Kendall's Advanced Theory of Statistics, Volume 1: Distribution Theory", Alan Stuart and Keith Ord, 6th Ed, (2009), {{ISBN|978-0-534-24312-8}}.</ref><ref name="Feller">William Feller, ''An Introduction to Probability Theory and Its Applications'', (Vol 1),  3rd Ed, (1968), Wiley, {{ISBN|0-471-25708-7}}.</ref> The higher the probability of an event, the more likely it is that the event will occur. A simple example is the tossing of a fair (unbiased) coin. Since the coin is fair, the two outcomes ("heads" and "tails") are both equally probable; the probability of "heads" equals the probability of "tails"; and since no other outcomes are possible, the probability of either "heads" or "tails" is 1/2 (which could also be written as 0.5 or 50%).}} 
{{term|term= '''[[Probability distribution]]'''}}{{defn|defn=In [[Probability theory|probability theory]] and [[Statistics|statistics]], a probability distribution is the mathematical [[Function (mathematics)|function]] that gives the probabilities of occurrence of different possible '''outcomes''' for an [[Experiment (probability theory)|experiment]].<ref name=":02">{{Cite book|title=The Cambridge dictionary of statistics|last=Everitt, Brian.|date=2006|publisher=Cambridge University Press|isbn=978-0-511-24688-3 |edition=3rd|location=Cambridge, UK|oclc=161828328}}</ref><ref>{{Cite book|title=Basic probability theory|last=Ash, Robert B.|date=2008|publisher=Dover Publications|isbn=978-0-486-46628-6|edition=Dover|location=Mineola, N.Y. |pages=66–69|oclc=190785258}}</ref> It is a mathematical description of a [[Randomness|random]] phenomenon in terms of its [[Sample space|sample space]] and the [[Probability|probabilities]] of [[Event (probability theory)|events]] (subsets of the sample space).<ref name=":1" />

For instance, if {{mvar|X}} is used to denote the outcome of a coin toss ("the experiment"), then the probability distribution of {{mvar|X}} would take the value 0.5 (1 in 2 or 1/2) for {{math|''X''&nbsp;{{=}} heads}}, and 0.5 for {{math|''X''&nbsp;{{=}} tails}} (assuming that the coin is fair). Examples of random phenomena include the weather condition in a future date, the height of a randomly selected person, the fraction of male students in a school, the results of a [[Engineering:Survey methodology|survey]] to be conducted, etc.<ref name="ross">{{cite book|first=Sheldon M.|last=Ross|title=A first course in probability|publisher=Pearson|year=2010}}</ref>}} 
{{term|term= '''[[Probability theory]]'''}}{{defn|defn=is the branch of [[Mathematics|mathematics]] concerned with [[Probability|probability]]. Although there are several different [[Probability interpretations|probability interpretations]], probability theory treats the concept in a rigorous mathematical manner by expressing it through a set of axioms. Typically these axioms formalise probability in terms of a [[Probability space|probability space]], which assigns a [[Measure (mathematics)|measure]] taking values between 0 and 1, termed the [[Probability measure|probability measure]], to a set of outcomes called the [[Sample space|sample space]]. Any specified subset of these outcomes is called an [[Event (probability theory)|event]].
Central subjects in probability theory include discrete and continuous [[Random variable|random variable]]s, probability distributions, and [[Stochastic process|stochastic process]]es, which provide mathematical abstractions of [[Determinism|non-deterministic]] or uncertain processes or measured [[Quantity|quantities]] that may either be single occurrences or evolve over time in a random fashion.
Although it is not possible to perfectly predict random events, much can be said about their behavior. Two major results in probability theory describing such behaviour are the [[Law of large numbers|law of large numbers]] and the [[Central limit theorem|central limit theorem]]. 

As a mathematical foundation for [[Statistics|statistics]], probability theory is essential to many human activities that involve quantitative analysis of data.<ref>[http://home.ubalt.edu/ntsbarsh/stat-data/Topics.htm Inferring From Data<!-- Bot generated title -->]</ref> Methods of probability theory also apply to descriptions of complex systems given only partial knowledge of their state, as in [[Physics:Statistical mechanics|statistical mechanics]] or [[Sequential estimation|sequential estimation]]. A great discovery of twentieth-century [[Physics:Physics|physics]] was the probabilistic nature of physical phenomena at atomic scales, described in [[Physics:Quantum mechanics|quantum mechanics]].<ref>{{cite web |title=Why is quantum mechanics based on probability theory? |work=StackExchange |date=July 1, 2014|url=https://physics.stackexchange.com/q/69718 }}{{Unreliable source?|date=February 2016}}</ref>}} 
{{term|term= '''[[Engineering:Pulley|Pulley]]'''}}{{defn|defn=Is a wheel on an [[Engineering:Axle|axle]] or [[Physics:Shaft (mechanical engineering)|shaft]] that is designed to support movement and change of direction of a taut cable or belt, or transfer of power between the shaft and cable or belt. In the case of a pulley supported by a frame or shell that does not transfer power to a shaft, but is used to guide the cable or exert a force, the supporting shell is called a block, and the pulley may be called a sheave.

A pulley may have a groove or grooves between [[Engineering:Flange|flange]]s around its [[Circumference|circumference]] to locate the cable or belt. The drive element of a pulley system can be a [[Engineering:Rope|rope]], [[Engineering:Wire rope|cable]], [[Engineering:Belt (mechanical)|belt]], or [[Engineering:Chain|chain]].}}
{{term|term= '''[[Engineering:Pump|Pump]]'''}}{{defn|defn= Is a device that moves fluids ([[Physics:Liquid|liquid]]s or [[Physics:Gas|gas]]es), or sometimes [[Physics:Slurry|slurries]], by mechanical action, typically converted from electrical energy into hydraulic energy. Pumps can be classified into three major groups according to the method they use to move the fluid: ''direct lift'', ''displacement'', and ''gravity'' pumps.<ref>[http://www.fao.org/docrep/010/ah810e/AH810E05.htm#5.3.1 Pump classifications]. Fao.org. Retrieved on 2011-05-25.</ref>

Pumps operate by some mechanism (typically [[Engineering:Reciprocating motion|reciprocating]] or [[Physics:Rotation|rotary]]), and consume [[Physics:Energy|energy]] to perform mechanical work moving the fluid. Pumps operate via many energy sources, including manual operation, [[Physics:Electricity|electricity]], engines, or wind power, and come in many sizes, from microscopic for use in medical applications, to large industrial pumps.}}
{{glossary end}}

==Q==
{{glossary}}

{{term|term= '''[[Physics:Quantum electrodynamics|Quantum electrodynamics]]'''}}{{defn|defn=In particle physics, quantum electrodynamics (QED) is the relativistic [[Physics:Quantum field theory|quantum field theory]] of [[Physics:Electrodynamics|electrodynamics]]. In essence, it describes how [[Physics:Light|light]] and [[Physics:Matter|matter]] interact and is the first theory where full agreement between [[Physics:Quantum mechanics|quantum mechanics]] and [[Physics:Special relativity|special relativity]] is achieved. QED mathematically describes all [[Philosophy:Phenomenon|phenomena]] involving [[Physics:Electric charge|electrically charged]] particles interacting by means of exchange of [[Physics:Photon|photon]]s and represents the [[Physics:Quantum mechanics|quantum]] counterpart of [[Physics:Classical electromagnetism|classical electromagnetism]] giving a complete account of matter and light interaction.}}
{{term|term= '''[[Physics:Quantum field theory|Quantum field theory]]'''}}{{defn|defn=In [[Physics:Theoretical physics|theoretical physics]], quantum field theory (QFT) is a theoretical framework that combines [[Physics:Classical field theory|classical field theory]], [[Physics:Special relativity|special relativity]] and [[Physics:Quantum mechanics|quantum mechanics]],<ref name="peskin">{{cite book |last1=Peskin |first1=M. |author-link=Michael Peskin |last2=Schroeder |first2=D.
 |year=1995
 |title=An Introduction to Quantum Field Theory
 |url=https://books.google.com/books?id=i35LALN0GosC
 |publisher=Westview Press
 |isbn=978-0-201-50397-5 }}</ref>{{rp|xi}} but ''not'' [[Physics:General relativity|general relativity]]'s description of [[Physics:Gravity|gravity]]. QFT is used in [[Physics:Particle physics|particle physics]] to construct [[Physical model|physical model]]s of [[Physics:Subatomic particle|subatomic particle]]s and in [[Physics:Condensed matter physics|condensed matter physics]] to construct models of [[Physics:Quasiparticle|quasiparticle]]s.}}
{{term|term= '''[[Physics:Quantum mechanics|Quantum mechanics]]'''}}{{defn|defn=Is a fundamental theory in [[Physics:Physics|physics]] that provides a description of the physical properties of [[Earth:Nature|nature]] at the scale of [[Physics:Atom|atom]]s and [[Physics:Subatomic particle|subatomic particle]]s.<ref name="Feynman">{{cite book
 | last1 = Feynman
 | first1 = Richard
 | last2 = Leighton
 | first2 = Robert
 | last3 = Sands
 | first3 = Matthew
 | title = The Feynman Lectures on Physics, Vol. 3
 | publisher = California Institute of Technology
 | date = 1964
 | url = https://www.feynmanlectures.caltech.edu/III_01.html
 | isbn = 978-0201500646
 | access-date = 2020-12-19
 }}</ref>{{rp|1.1}} It is the foundation of all quantum physics including [[Chemistry:Quantum chemistry|quantum chemistry]], [[Physics:Quantum field theory|quantum field theory]], [[Engineering:Quantum technology|quantum technology]], and [[Quantum information science|quantum information science]].}}

{{glossary end}}

==R==
{{glossary}}

{{term|term= '''[[Physics:Regelation|Regelation]]'''}}{{defn|defn=The phenomena of melting under pressure, then freezing when the pressure is reduced.}} 
{{term|term= '''[[Physics:Relative density|Relative density]]'''}}{{defn|defn=Relative density, or specific gravity,<ref name=specificgravity1>{{cite book| last = Dana| first = Edward Salisbury
|title = A text-book of mineralogy: with an extended treatise on crystallography...
|publisher = John Wiley and Sons| date = 1922| location = New York, London(Chapman Hall)
|pages = 195–200, 316
|url = https://books.google.com/books?id=rCwaAAAAYAAJ&pg=PA156}}</ref><ref name=specificgravity2>{{cite book
|last = Schetz| first = Joseph A.|author2=Allen E. Fuhs
 |title = Fundamentals of fluid mechanics| publisher =Wiley, John & Sons, Incorporated
|date =1999-02-05|pages = 111, 142, 144, 147, 109, 155, 157, 160, 175
|url =https://books.google.com/books?id=YCSSolzuu9IC&pg=PP1|isbn =0-471-34856-2}}</ref> is the [[Ratio|ratio]] of the [[Physics:Density|density]] (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for liquids is nearly always measured with respect to [[Chemistry:Water (molecule)|water]] at its densest (at {{cvt|4|°C|°F|1|disp=or}}); for gases, the reference is air at [[Physics:Room temperature|room temperature]] ({{cvt|20|°C|°F|disp=or}}). The term "relative density" is often preferred in scientific usage.}} 
{{term|term= '''[[Physics:Relative velocity|Relative velocity]]'''}}{{defn|defn=The ''relative velocity'' <math>\vec{v}_{B\mid A}</math> (also <math>\vec{v}_{BA}</math> or <math>\vec{v}_{B \operatorname{rel} A}</math>) is the velocity of an object or observer '''B''' in the rest frame of another object or observer '''A'''.}}
{{term|term= '''[[Reliability engineering]]'''}}{{defn|defn=Is a sub-discipline of [[Engineering:Systems engineering|systems engineering]] that emphasizes the ability of equipment to function without failure. Reliability describes the ability of a system or component to function under stated conditions for a specified period of time.<ref>Institute of Electrical and Electronics Engineers (1990) IEEE Standard Computer Dictionary: A Compilation of IEEE Standard Computer Glossaries. New York, NY {{ISBN|1-55937-079-3}}</ref> Reliability is closely related to [[Availability|availability]], which is typically described as the ability of a component or system to function at a specified moment or interval of time.}}
{{term|term= '''[[Physics:Electrical resistivity and conductivity|Resistivity]]'''}}{{defn|defn=Electrical resistivity (also called specific electrical resistance or volume resistivity) and its inverse, electrical conductivity, is a fundamental property of  a material that quantifies how strongly it resists or conducts [[Physics:Electric current|electric current]]. A low resistivity indicates a material that readily allows electric current. Resistivity is commonly represented by the Greek letter ''ρ''&nbsp;(rho). The SI unit of electrical resistivity is the [[Ohm|ohm]]-meter (Ω⋅m).<ref>{{cite book | last = Lowrie | first = William |  title = Fundamentals of Geophysics | url = https://books.google.com/books?id=h2-NjUg4RtEC&pg=PA254 | publisher = Cambridge University Press | isbn = 978-05-2185-902-8 | pages = 254–55 | date = 2007 | access-date = March 24, 2019 }}</ref><ref>{{cite book | first = Narinder | last = Kumar | title = Comprehensive Physics for Class XII | url = https://books.google.com/books?id=IryMtwHHngIC&pg=PA282 | date = 2003 | publisher = Laxmi Publications | location = New Delhi | isbn = 978-81-7008-592-8 | pages = 280–84 | access-date = March 24, 2019 }}</ref><ref>{{cite book | first = Eric | last = Bogatin | title = Signal Integrity: Simplified | url = https://books.google.com/books?id=_IiONSphoB4C&q=Signal%20integrity&pg=PA114 | year = 2004 | publisher = Prentice Hall Professional | isbn = 978-0-13-066946-9 | page = 114 | access-date = March 24, 2019 }}</ref> For example, if a {{nowrap|1 m × 1 m × 1 m}} solid cube of material has sheet contacts on two opposite faces, and the resistance between these contacts is 1&nbsp;Ω, then the resistivity of the material is 1&nbsp;Ω⋅m.}}
{{term|term= '''[[Engineering:Resistor|Resistor]]'''}}{{defn|defn=Is a [[Engineering:Passivity (engineering)|passive]] [[Engineering:Terminal (electronics)|two-terminal]] [[Engineering:Electronic component|electrical component]] that implements [[Physics:Electrical resistance|electrical resistance]] as a circuit element. In electronic circuits, resistors are used to reduce current flow, adjust signal levels, to [[Physics:Voltage divider|divide voltages]], [[Engineering:Biasing|bias]] active elements, and terminate [[Engineering:Transmission line|transmission line]]s, among other uses. High-power resistors that can dissipate many [[Watt|watt]]s of electrical power as heat, may be used as part of motor controls, in power distribution systems, or as test loads for [[Engineering:Electric generator|generators]].
Fixed resistors have resistances that only change slightly with temperature, time or operating voltage. Variable resistors can be used to adjust circuit elements (such as a volume control or a lamp dimmer), or as sensing devices for heat, light, humidity, force, or chemical activity.}}
{{term|term= '''[[Reynolds number]]'''}}{{defn|defn=The Reynolds number ({{math|Re}}) helps predict flow patterns in different fluid flow situations. At low Reynolds numbers, flows tend to be dominated by laminar (sheet-like) flow, while at high Reynolds numbers flows tend to be turbulent. The turbulence results from differences in the fluid's speed and direction, which may sometimes intersect or even move counter to the overall direction of the flow ([[Physics:Eddy (fluid dynamics)|eddy currents]]). These eddy currents begin to churn the flow, using up energy in the process, which for liquids increases the chances of [[Physics:Cavitation|cavitation]]. Reynolds numbers are an important [[Physics:Dimensionless quantity|dimensionless quantity]] in [[Physics:Fluid mechanics|fluid mechanics]].}}
{{term|term= '''[[Physics:Rheology|Rheology]]'''}}{{defn|defn=Is the study of the flow of matter, primarily in a liquid or gas state, but also as "soft solids" or solids under conditions in which they respond with plastic flow rather than deforming elastically in response to an applied force. Rheology is a branch of physics, and it is the science that deals with the deformation and flow of materials, both solids and liquids.<ref name=Schowalter>W. R. Schowalter (1978) Mechanics of Non-Newtonian Fluids Pergamon {{ISBN|0-08-021778-8}}</ref>}}
{{term|term= '''[[Rigid body]]'''}}{{defn|defn=In [[Physics:Physics|physics]], a rigid body (also known as a ''rigid object'' <ref>{{cite book|title=Introduction to Statics and Dynamics|author=Andy Ruina and Rudra Pratap|publisher=Oxford University Press|year=2015}} (link: [http://ruina.tam.cornell.edu/Book/])</ref>) is a solid [[Philosophy:Physical body|body]] in which [[Engineering:Deformation (engineering)|deformation]] is zero or so small it can be neglected. The [[Distance|distance]] between any two given [[Point (geometry)|point]]s on a rigid body remains constant in time regardless of external [[Physics:Force|force]]s or [[Physics:Moment|moments]] exerted on it. A rigid body is usually considered as a [[Physics:Continuum mechanics|continuous distribution]] of [[Physics:Mass|mass]]. In the study of [[Physics:Special relativity|special relativity]], a perfectly rigid body does not exist; and objects can only be assumed to be rigid if they are not moving near the [[Physics:Speed of light|speed of light]]. In [[Physics:Quantum mechanics|quantum mechanics]], a rigid body is usually thought of as a collection of [[Physics:Point particle|point masses]]. For instance, molecules (consisting of the point masses: electrons and nuclei) are often seen as rigid bodies (see [[Physics:Rotational spectroscopy#Classification of molecules based on rotational behavior|classification of molecules as rigid rotors]]).}}
{{term|term= '''[[Astronomy:Robonaut|Robonaut]]'''}}{{defn|defn=A development project conducted by NASA to create humanoid robots capable of using space tools and working in similar environments to suited astronauts.}}
{{term|term='''[[Engineering:Robot-assisted surgery|Robot-assisted surgery]]'''}}{{defn|defn='''Robotic surgery''' are types of [[Medicine:Surgery|surgical procedures]] that are done using [[Engineering:Robot|robot]]ic systems. Robotically-assisted surgery was developed to try to overcome the limitations of pre-existing minimally-invasive surgical procedures and to enhance the capabilities of surgeons performing open surgery.

In the case of robotically-assisted minimally-invasive surgery, instead of directly moving the instruments, the surgeon uses one of two methods to administer the instruments. These include using a direct [[Engineering:Remote manipulator|telemanipulator]] or through computer control. A telemanipulator is a remote manipulator that allows the surgeon to perform the normal movements associated with the surgery. The [[Engineering:Robotic arm|robotic arm]]s carry out those movements using end-effectors and [[Engineering:Manipulator (device)|manipulators]] to perform the actual surgery. In computer-controlled systems, the surgeon uses a computer to control the robotic arms and its end-effectors, though these systems can also still use telemanipulators for their input. One advantage of using the computerized method is that the surgeon does not have to be present, leading to the possibility for [[Medicine:Remote surgery|remote surgery]].}}
{{term|term= '''Robotics'''}}{{defn|defn=Is an [[Philosophy:Interdisciplinarity|interdisciplinary]] field that integrates [[Computer science|computer science]] and [[Engineering:Engineering|engineering]].<ref>{{cite web|last=|first=|date=|title=German National Library|url=https://portal.dnb.de/opac.htm?method=simpleSearch&cqlMode=true&query=nid%3D4261462-4|access-date=|website=International classification system of the German National Library (GND)}}</ref> Robotics involves design, construction, operation, and use of [[Engineering:Robot|robot]]s. The goal of robotics is to design machines that can help and assist humans. Robotics integrates fields of [[Engineering:Mechanical engineering|mechanical engineering]], [[Electrical engineering|electrical engineering]], [[Information engineering (field)|information engineering]], [[Mechatronics|mechatronics]], [[Engineering:Electronics|electronics]], bioengineering, [[Computer engineering|computer engineering]], control engineering, [[Software engineering|software engineering]], among others.}}
{{term|term= '''[[Root mean square]]'''}}{{defn|defn=In [[Mathematics|mathematics]] and its applications, the root mean square (RMS or rms) is defined as the [[Square root|square root]] of the [[Mean square|mean square]] (the [[Arithmetic mean|arithmetic mean]] of the [[Square (algebra)|squares]] of a [[Set (mathematics)|set]] of numbers).<ref name=dicphys>{{cite book
|title=A Dictionary of Physics (6 ed.)
|publisher=Oxford University Press
|year=2009
|isbn=9780199233991
|url=https://www.oxfordreference.com/view/10.1093/acref/9780199233991.001.0001/acref-9780199233991-e-2676
}}</ref>
The RMS is also known as the ''quadratic mean''<ref>{{cite book |last1=Thompson |first1=Sylvanus P. |title=Calculus Made Easy |date=1965 |publisher=Macmillan International Higher Education |isbn=9781349004874 |page=185 |url=https://books.google.com/books?id=6VJdDwAAQBAJ&pg=PA185 |access-date=5 July 2020}}</ref><ref>{{cite book |last1=Jones |first1=Alan R. |title=Probability, Statistics and Other Frightening Stuff |date=2018 |publisher=Routledge |isbn=9781351661386 |page=48 |url=https://books.google.com/books?id=OvtsDwAAQBAJ&pg=PA48 |access-date=5 July 2020}}</ref> and is a particular case of the [[Generalized mean#Quadratic|generalized mean]] with exponent&nbsp;2. RMS can also be defined for a continuously varying [[Function (mathematics)|function]] in terms of an [[Integral|integral]] of the squares of the instantaneous values during a cycle. For [[Physics:Alternating current|alternating electric current]], RMS is equal to the value of the constant [[Physics:Direct current|direct current]] that would produce the same power dissipation in a [[Engineering:Resistor|resistive load]].<ref name=dicphys/> In [[Estimation theory|estimation theory]], the [[Root-mean-square deviation|root-mean-square deviation]] of an estimator is a measure of the imperfection of the fit of the estimator to the data.}}
{{term|term= '''[[Physics:Root-mean-square speed|Root-mean-square speed]]'''}}{{defn|defn=In the [[Physics:Physics|physics]] of [[Physics:Gas|gas]] molecules, the root-mean-square speed is defined as the square root of the average squared-speed. The RMS speed of an ideal gas is [[Maxwell–Boltzmann distribution#Distribution for the velocity vector|calculated]] using the following equation:
:<math>v_\text{RMS} = \sqrt{3RT \over M}</math>

where ''R'' represents the [[Physics:Gas constant|gas constant]], 8.314&nbsp;J/(mol·K), ''T'' is the temperature of the gas in [[Kelvin|kelvin]]s, and ''M'' is the [[Physics:Molar mass|molar mass]] of the gas in kilograms per mole. In physics, speed is defined as the scalar magnitude of velocity. For a stationary gas, the average speed of its molecules can be in the order of thousands of km/hr, even though the average velocity of its molecules is zero.}}
{{term|term= '''[[Rotational energy]]'''}}{{defn|defn=Rotational energy or ''angular kinetic energy'' is [[Physics:Kinetic energy|kinetic energy]] due to the [[Rotation around a fixed axis|rotation]] of an object and is part of its [[Physics:Kinetic energy#Rotation in systems|total kinetic energy]]. Looking at rotational energy separately around an object's [[Physics:Axis of rotation|axis of rotation]], the following dependence on the object's [[Physics:Moment of inertia|moment of inertia]] is observed:

:<math>E_\mathrm{rotational} = \frac{1}{2} I \omega^2 </math>
where
: <math> \omega \ </math> is the [[Physics:Angular velocity|angular velocity]]
: <math> I \ </math> is the [[Physics:Moment of inertia|moment of inertia]] around the axis of rotation
: <math> E \ </math> is the [[Physics:Kinetic energy|kinetic energy]]}}
{{term|term= '''[[Physics:Rotational speed|Rotational speed]]'''}}{{defn|defn=Rotational speed (or ''speed of revolution'') of an object rotating around an axis is the number of [[Turn (geometry)|turns]] of the object divided by time, specified as [[Revolutions per minute|revolutions per minute]] (rpm), cycles per second (cps), radians per second (rad/s), etc.<ref>{{Cite book
|last1=Atkins
|first1=Tony
|last2=Escudier
|first2=Marcel
|title=A Dictionary of Mechanical Engineering
|year=2013
|url=http://www.oxfordreference.com/view/10.1093/acref/9780199587438.001.0001/acref-9780199587438-e-5953?rskey=EBYJmx&result=1
|publisher=Oxford University Press
|isbn=9780199587438
}}</ref>

The symbol for rotational speed is <math>\omega_\text{cyc}</math>{{Citation needed|date=February 2015|reason=sub "cyc"?}}(the Greek lowercase letter "omega").

[[Physics:Speed#Tangential speed|Tangential speed]] ''v'', rotational speed <math>\omega_\text{cyc}</math>, and radial distance ''r'', are related by the following equation:<ref>http://hyperphysics.phy-astr.gsu.edu/hbase/rotq.html</ref>

:<math>v = 2\pi r\omega_\text{cyc}</math>

:<math>v = r\omega_\text{rad}</math>

An algebraic rearrangement of this equation allows us to solve for rotational speed:

:<math>\omega_\text{cyc} = v/2\pi r</math>

:<math>\omega_\text{rad} = v/r</math>

Thus, the tangential speed will be directly proportional to ''r'' when all parts of a system simultaneously have the same ω, as for a wheel, disk, or rigid wand. The direct proportionality of ''v'' to ''r'' is not valid for the [[Astronomy:Planet|planet]]s, because the planets have different rotational speeds (ω).

Rotational speed can measure, for example, how fast a motor is running. Rotational speed and angular speed are sometimes used as synonyms, but typically they are measured with a different unit. Angular speed, however, tells the change in [[Angle|angle]] per time unit, which is measured in [[Radian per second|radians per second]] in the SI system. Since there are 2π radians per cycle, or 360 degrees per cycle, we can convert angular speed to rotational speed by

:<math>\omega_\text{cyc} = \omega_\text{rad}/2\pi\,</math>
and
:<math>\omega_\text{cyc} = \omega_\text{deg}/360\,</math>

where
* <math>\omega_\text{cyc}\,</math> is rotational speed in cycles per second
* <math>\omega_\text{rad}\,</math> is angular speed in radians per second
* <math>\omega_\text{deg}\,</math> is angular speed in degrees per second

For example, a [[Engineering:Stepper motor|stepper motor]] might turn exactly one complete revolution each second.
Its angular speed is 360 [[Degree (angle)|degrees]] per second (360°/s), or 2π [[Radian|radian]]s per second (2π rad/s), while the rotational speed is 60 rpm.

Rotational speed is not to be confused with [[Physics:Speed#Tangential speed|tangential speed]], despite some relation between the two concepts. Imagine a rotating merry-go-round. No matter how close or far you stand from the axis of rotation, your rotational speed will remain constant. However, your tangential speed does not remain constant. If you stand two meters from the axis of rotation, your tangential speed will be double the amount if you were standing only one meter from the axis of rotation.}}
{{glossary end}}

==S==
{{glossary}}

{{term|term= '''Safe failure fraction (SFF)'''}}{{defn|defn=A term used in [[Functional safety|functional safety]] for the proportion of failures that are either non-[[Hazard|hazard]]ous or detected automatically. The opposite of SFF is the proportion of undetected, hazardous failures.<ref>{{cite web |title=Safe Failure Fraction |url=https://www.sciencedirect.com/topics/engineering/safe-failure-fraction |website=ScienceDirect |access-date=21 September 2020}}</ref>}}
{{term|term= '''[[Chemistry:Safety data sheet|Safety data sheet]]'''}}{{defn|defn=A safety data sheet (SDS),<ref>{{cite web|url=http://www.unece.org/trans/danger/publi/ghs/ghs_rev04/04files_e.htmlUnited|title=Transport - Transport - UNECE|website=Unece.org|access-date=22 December 2017}}</ref> material safety data sheet (MSDS),  or product safety data sheet (PSDS) are documents that list information relating to [[Social:Occupational safety and health|occupational safety and health]] for the use of various substances and products. SDSs are a widely used system for cataloguing information on chemicals, [[Chemistry:Chemical compound|chemical compound]]s, and chemical [[Physics:Mixture|mixture]]s. SDS information may include instructions for the safe use and potential hazards associated with a particular material or product, along with spill-handling procedures. The older MSDS formats could vary from source to source within a country depending on national requirements; however, the newer SDS format is internationally standardized.}}
{{term|term= '''[[Engineering:Sanitary engineering|Sanitary engineering]]'''}}{{defn|defn=Sanitary engineering, also known as public health engineering or wastewater engineering, is the application of engineering methods to improve [[Engineering:Sanitation|sanitation]] of human communities, primarily by providing the removal and disposal of human waste, and in addition to the supply of safe potable water.}}
{{term|term= '''Saturated compound'''}}{{defn|defn=In [[Chemistry:Chemistry|chemistry]], a saturated compound is a [[Chemistry:Chemical compound|chemical compound]] (or ion) that resists the addition reactions, such as [[Chemistry:Hydrogenation|hydrogenation]], [[Chemistry:Oxidative addition|oxidative addition]], and binding of a Lewis base. The term is used in many contexts and for many classes of chemical compounds. Overall, saturated compounds are less reactive than unsaturated compounds. Saturation is derived from the Latin word ''saturare'', meaning 'to fill')<ref>''Mosby's Medical, Nursing & Allied Health Dictionary'', Fourth Edition, Mosby-Year Book Inc., 1994, p. 1394</ref>}}
{{term|term= '''[[Scalar (mathematics)]]'''}}{{defn|defn=.}}
{{term|term= '''[[Physics:Scalar|Scalar]]'''}}{{defn|defn=.}}
{{term|term= '''[[Scalar multiplication]]'''}}{{defn|defn=In [[Mathematics|mathematics]], scalar multiplication is one of the basic operations defining a [[Vector space|vector space]] in [[Linear algebra|linear algebra]]<ref>{{cite book | last=Lay | first=David C. | title=Linear Algebra and Its Applications | url=https://archive.org/details/studyguidetoline0000layd | url-access=registration | publisher=Addison–Wesley | year=2006 | edition = 3rd | isbn=0-321-28713-4}}</ref><ref>{{cite book | last=Strang | first=Gilbert |  title=Linear Algebra and Its Applications | publisher=Brooks Cole | year=2006 | edition = 4th | isbn=0-03-010567-6}}</ref><ref>{{cite book | last = Axler | first = Sheldon | title = Linear Algebra Done Right | publisher = [[Company:Springer Science+Business Media|Springer]] | year = 2002 | edition = 2nd | isbn = 0-387-98258-2}}</ref> (or more generally, a [[Module (mathematics)|module]] in [[Abstract algebra|abstract algebra]]<ref>{{cite book | last1=Dummit | first1=David S. | last2=Foote | first2=Richard M. | title=Abstract Algebra | publisher={{wipe|John Wiley & Sons}} | year=2004 | edition=3rd | isbn=0-471-43334-9}}</ref><ref>{{cite book | last=Lang | first=Serge | author-link=Serge Lang | title=Algebra | publisher=[[Company:Springer Science+Business Media|Springer]] | series=[[Graduate Texts in Mathematics]] | year=2002 | isbn=0-387-95385-X}}</ref>). In common geometrical contexts, scalar multiplication of a [[Real number|real]] [[Euclidean vector]] by a positive real number multiplies the magnitude of the vector—without changing its direction. The term "[[Scalar (mathematics)|scalar]]" itself derives from this usage: a scalar is that which scales vectors. Scalar multiplication is the multiplication of a vector by a scalar (where the product is a vector), and is to be distinguished from inner product of two vectors (where the product is a scalar).}}
{{term|term= '''[[Engineering:Screw (simple machine)|Screw]]'''}}{{defn|defn=A screw is a mechanism that converts [[Physics:Rotation|rotation]]al motion to [[Physics:Linear motion|linear motion]], and a [[Physics:Torque|torque]] (rotational force) to a linear [[Physics:Force|force]].<ref name="Young" >{{cite web
  | last = Young
  | first = James F.
  | title = Basic Mechanics
  | work = ELEC 201:Introduction to Engineering Design
  | publisher = Electrical and Computer Engineering Dept., Rice Univ.
  | year = 2000
  | url = http://www.clear.rice.edu/elec201/Book/basic_mech.html
  | access-date = 2011-03-29}}</ref> It is one of the six classical [[Engineering:Simple machine|simple machine]]s. The most common form consists of a cylindrical shaft with [[Helix|helical]] grooves or ridges called ''[[Engineering:Screw thread|threads]]'' around the outside.<ref>{{cite book
  | last = Morris
  | first = William, Ed.
  | title = The American Heritage Dictionary, New College Edition
  | publisher = Houghton Mifflin
  | year = 1979
  | location = USA
  | pages = [https://archive.org/details/americanheritag00morr/page/1167 1167]
  | url = https://archive.org/details/americanheritag00morr/page/1167
  | isbn = 0-395-20360-0
  }}</ref><ref>{{cite web
  | title = Screw
  | work = How Stuff Works website
  | publisher = Discovery Communications
  | year = 2011
  | url = http://science.howstuffworks.com/screw-info.htm
  | access-date = 2011-03-29}}</ref> The screw passes through a hole in another object or medium, with threads on the inside of the hole that mesh with the screw's threads. When the shaft of the screw is rotated relative to the stationary threads, the screw moves along its axis relative to the medium surrounding it; for example rotating a [[Engineering:Wood screw|wood screw]] forces it into wood. In screw mechanisms, either the screw shaft can rotate through a threaded hole in a stationary object, or a threaded collar such as a [[Engineering:Nut (hardware)|nut]] can rotate around a stationary screw shaft.<ref name="Collins">{{cite book   
  | last = Collins
  | first = Jack A. 
  |author2=Henry R. Busby |author3=George H. Staab
   | title = Mechanical Design of Machine Elements and Machines, 2nd Ed
  | publisher = John Wiley and Sons
  | year = 2009
  | location = USA
  | pages = 462–463
  | url = https://books.google.com/books?id=909-5C4eyUkC&q=screw+machine+lead+pitch+advantage&pg=PA464
  | isbn = 978-0-470-41303-6}}</ref><ref name="Bhandari">{{cite book   
  | last = Bhandari
  | first = V. B.
  | title = Design of machine elements
  | publisher = Tata McGraw-Hill
  | year = 2007
  | location = New Delhi
  | pages = 202–206
  | url = https://books.google.com/books?id=d-eNe-VRc1oC&q=%22simple+machine%22+scr&pg=PP12
  | isbn = 978-0-07-061141-2}}</ref>  Geometrically, a screw can be viewed as a narrow [[Engineering:Inclined plane|inclined plane]] wrapped around a cylinder.<ref name="Young" />}}
{{term|term= '''Series circuit'''}}{{defn|defn=An electrical circuit in which the same current passes through each component, with only one path.}}
{{term|term= '''Servo'''}}{{defn|defn=A motor that moves to and maintains a set position under command, rather than continuously moving.}} 
{{term|term= '''[[Servomechanism]]'''}}{{defn|defn=An automatic device that uses error-sensing negative feedback to correct the performance of a mechanism.}} 
{{term|term= '''Shadow matter'''}}{{defn|defn=In [[Physics:Physics|physics]], mirror matter, also called shadow matter or Alice matter, is a hypothetical counterpart to ordinary matter.<ref name="urlSigns of dark matter may point to mirror matter candidate">{{cite web |url=https://phys.org/news/2010-04-dark-mirror-candidate.html |title=Signs of dark matter may point to mirror matter candidate }}</ref>}}
{{term|term= '''[[Physics:Shear flow|Shear flow]]'''}}{{defn|defn=The term shear flow is used in [[Physics:Solid mechanics|solid mechanics]] as well as in [[Physics:Fluid dynamics|fluid dynamics]].  The expression ''shear flow'' is used to indicate:
* a [[Physics:Shear stress|shear stress]] over a distance in a thin-walled structure (in solid mechanics);<ref name=HOSW4-9>Higdon, Ohlsen, Stiles and Weese (1960), ''Mechanics of Materials'', article 4-9 (2nd edition), John Wiley & Sons, Inc., New York. Library of Congress CCN 66-25222</ref>
* the flow ''induced'' by a force (in a fluid).}}
{{term|term= '''[[Engineering:Shear strength|Shear strength]]'''}}{{defn|defn=Is the strength of a material or component against the type of [[Engineering:Yield (engineering)|yield]] or structural failure when the material or component fails in [[Physics:Shearing|shear]]. A shear load is a [[Physics:Force|force]] that tends to produce a sliding failure on a material along a plane that is parallel to the direction of the force. When a paper is cut with scissors, the paper fails in shear.

In [[Engineering:Structural engineering|structural]] and  [[Engineering:Mechanical engineering|mechanical engineering]], the shear strength of a component is important for designing the dimensions and materials to be used for the manufacture or construction of the component (e.g. [[Physics:Beam (structure)|beams]], plates, or [[Engineering:Screw|bolts]]). In a [[Physics:Reinforced concrete|reinforced concrete]] beam, the main purpose of reinforcing bar (rebar) stirrups is to increase the shear strength.}}
{{term|term= '''[[Physics:Shear stress|Shear stress]]'''}}{{defn|defn=Shear stress, often denoted by '''{{mvar|τ}}''' (Greek: tau), is the component of [[Physics:Stress|stress]] coplanar with a material cross section. It arises from the [[Physics:Shear force|shear force]], the component of [[Physics:Force|force]] vector [[Parallel (geometry)|parallel]] to the material cross section.  Normal stress, on the other hand, arises from the force vector component [[Perpendicular|perpendicular]] to the material cross section on which it acts.}}
{{term|term= '''[[Shortwave radiation]]'''}}{{defn|defn=Shortwave radiation (SW) is [[Physics:Radiant energy|radiant energy]] with wavelengths in the visible (VIS), near-ultraviolet (UV), and near-infrared (NIR) spectra.

There is no standard cut-off for the near-infrared range; therefore, the shortwave radiation range is also variously defined. It may be broadly defined to include all radiation with a wavelength of 0.1[[Micrometre|μm]] and 5.0μm or narrowly defined so as to include only radiation between 0.2μm and 3.0μm.

There is little radiation flux (in terms of [[Physics:Irradiance|W/m<sup>2</sup>]]) to the Earth's surface below 0.2μm or above 3.0μm, although photon flux remains significant as far as 6.0μm, compared to shorter wavelength fluxes.  UV-C radiation spans from 0.1μm to .28μm, UV-B from 0.28μm to 0.315μm, UV-A from 0.315μm to 0.4μm, the visible spectrum from 0.4μm to 0.7μm, and NIR arguably from 0.7μm to 5.0μm, beyond which the infrared is thermal.<ref>However, the definition of thermal infrared may start at wavelengths as short as 1.1μm (longer than which optical instruments have difficulty measuring) or anywhere between 2.0μm and 4.0μm, depending on the method of measurement and its purpose.</ref>

Shortwave radiation is distinguished from longwave radiation. Downward shortwave radiation is sensitive to [[Astronomy:Solar zenith angle|solar zenith angle]], [[Earth:Cloud cover|cloud cover]].<ref>[https://dx.doi.org/10.1016/j.rse.2012.04.006 L. Chen, G. Yan, T. Wang, H. Ren, J. Calbó, J. Zhao, R. McKenzie (2012), Estimation of surface shortwave radiation components under all sky conditions: Modeling and sensitivity analysis, Remote Sensing of Environment, 123: 457–469.]</ref>}}
{{term|term= '''SI units'''}}{{defn|defn=The  '''International System of Units''' ('''SI''', abbreviated from the [[Social:French language|French]] ''{{lang|fr|Système international (d'unités)}}'') is the modern form of the [[Metric system|metric system]]. It is the only [[System of measurement|system of measurement]] with an official status in nearly every country in the world. It comprises a [[Coherence (units of measurement)|coherent]] system of units of measurement starting with seven [[SI base unit|base unit]]s, which are the [[Second|second]] (the unit of [[Time|time]] with the symbol s), [[Metre|metre]] ([[Physics:Length|length]], m), [[Kilogram|kilogram]] ([[Physics:Mass|mass]], kg), [[Ampere|ampere]] ([[Physics:Electric current|electric current]], A), [[Kelvin|kelvin]] ([[Physics:Thermodynamic temperature|thermodynamic temperature]], K), [[Mole (unit)|mole]] ([[Physics:Amount of substance|amount of substance]], mol), and [[Candela|candela]] ([[Physics:Luminous intensity|luminous intensity]], cd). The system allows for an unlimited number of additional units, called [[SI derived unit|derived units]], which can always be represented as products of powers of the base units.{{efn|For example, the SI unit of [[Physics:Velocity|velocity]] is the metre per second, m⋅s<sup>−1</sup>; of [[Physics:Acceleration|acceleration]] is the metre per second squared, m⋅s<sup>−2</sup>; etc.}} Twenty-two derived units have been provided with special names and symbols.{{efn|For example the [[Newton (unit)|newton]] (N), the unit of [[Physics:Force|force]], equivalent to kg⋅m⋅s<sup>−2</sup>; the [[Joule|joule]] (J), the unit of [[Physics:Energy|energy]], equivalent to kg⋅m<sup>2</sup>⋅s<sup>−2</sup>, etc. The most recently named derived unit, the [[Katal|katal]], was defined in 1999.}} The seven base units and the 22 derived units with special names and symbols may be used in combination to express other derived units,{{efn|For example, the recommended unit for the [[Physics:Electric field|electric field strength]] is the volt per metre, V/m, where the [[Volt|volt]] is the derived unit for [[Physics:Voltage|electric potential difference]]. The volt per metre is equal to kg⋅m⋅s<sup>−3</sup>⋅A<sup>−1</sup> when expressed in terms of base units.}} which are adopted to facilitate measurement of diverse quantities. The SI also provides twenty [[Metric prefix|prefix]]es to the unit names and unit symbols that may be used when specifying power-of-ten (i.e. decimal) multiples and sub-multiples of SI units. The SI is intended to be an evolving system; units and prefixes are created and unit definitions are modified through international agreement as the technology of [[Measurement|measurement]] progresses and the precision of measurements improves.}} 
{{term|term= '''[[Signal processing]]'''}}{{defn|defn=Is an [[Electrical engineering|electrical engineering]] subfield that focuses on analysing, modifying, and synthesizing [[Signal|signal]]s such as [[Audio signal processing|sound]], [[Image processing|images]], and scientific measurements.<ref>{{cite journal|last=Sengupta|first=Nandini|author2=Sahidullah, Md|author3=Saha, Goutam|date=August 2016|title=Lung sound classification using cepstral-based statistical features|journal=Computers in Biology and Medicine|volume=75|issue=1|pages=118–129|doi=10.1016/j.compbiomed.2016.05.013|pmid=27286184}}</ref> Signal processing techniques can be used to improve transmission, storage efficiency and subjective quality and to also emphasize or detect components of interest in a measured signal.<ref>{{cite book|title=Discrete-Time Signal Processing|author=Alan V. Oppenheim and Ronald W. Schafer|publisher=Prentice Hall|year=1989|isbn=0-13-216771-9|page=1}}</ref>}}
{{term|term= '''[[Engineering:Simple machine|Simple machine]]'''}}{{defn|defn=Is a mechanical device that changes the direction or magnitude of a [[Physics:Force|force]].<ref name="Paul-Roy-Mukherjee-2005">{{Citation |last1=Paul |first1=Akshoy |last2=Roy |first2=Pijush |last3=Mukherjee |first3=Sanchayan |title=Mechanical sciences: engineering mechanics and strength of materials |year=2005 |publisher=Prentice Hall of India |isbn=978-81-203-2611-8 |page=215 |postscript=.}}</ref> In general, they can be defined as the simplest mechanisms that use [[Physics:Mechanical advantage|mechanical advantage]] (also called [[Engineering:Lever|lever]]age) to multiply force.<ref name="Asimov1988">{{Citation |last=Asimov |first=Isaac |title=Understanding Physics |year=1988 |publisher=Barnes & Noble |location=New York |isbn=978-0-88029-251-1 |url=https://books.google.com/books?id=pSKvaLV6zkcC&q=Asimov+simple+machine&pg=PA88 |page=88 |postscript=.}}</ref> Usually the term refers to the six classical simple machines that were defined by [[Philosophy:Renaissance|Renaissance]] scientists:<ref name="Anderson">{{cite book
  |last=Anderson
  |first=William Ballantyne
  |title=Physics for Technical Students: Mechanics and Heat
  |year=1914
  |publisher=McGraw Hill
  |location=New York
  |url=https://archive.org/details/bub_gb_Pa0IAAAAIAAJ/page/n131
  |access-date=2008-05-11
  |pages=112}}</ref><ref name="Britannica1773">{{cite encyclopedia
  | title = Mechanics
  | encyclopedia = Encyclopaedia Britannica
  | volume = 3
  | pages = 44
  | publisher = John Donaldson
  | date =1773
  | url = https://books.google.com/books?id=Ow8UAAAAQAAJ&q=%22simple+machine%22+%22mechanical+powers%22+lever+screw+inclined+plane+wedge+wheel+pulley&pg=PA44
  | access-date = 5 April 2020}}</ref><ref name="Morris">{{cite book
 | last1  = Morris
 | first1 = Christopher G. 
 | title  = Academic Press Dictionary of Science and Technology
 | publisher = Gulf Professional Publishing
 | date   = 1992
 | pages  = 1993
 | url    = https://books.google.com/books?id=nauWlPTBcjIC&q=%22simple+machine%22&pg=PA1993
 | isbn   = 9780122004001
 }}</ref>

* [[Engineering:Lever|Lever]]
* [[Engineering:Wheel and axle|Wheel and axle]]
* [[Engineering:Pulley|Pulley]]
* [[Engineering:Inclined plane|Inclined plane]]
* Wedge
* [[Engineering:Screw (simple machine)|Screw]]}}
{{term|term= '''[[Physics:Siphon|Siphon]]'''}}{{defn|defn=A closed tube that conveys liquids between two levels without pumping.}}
{{term|term= '''[[Physics:Solid mechanics|Solid mechanics]]'''}}{{defn|defn=Also known as '''mechanics of solids''', is the branch of [[Physics:Continuum mechanics|continuum mechanics]] that studies the behavior of [[Physics:Solid|solid]] materials, especially their motion and [[Physics:Deformation (mechanics)|deformation]] under the action of [[Physics:Force|force]]s, [[Physics:Temperature|temperature]] changes, phase changes, and other external or internal agents.}}
{{term|term= '''[[Physics:Solid-state physics|Solid-state physics]]'''}}{{defn|defn=Is the study of rigid [[Physics:Matter|matter]], or [[Physics:Solid|solid]]s, through methods such as [[Physics:Quantum mechanics|quantum mechanics]], [[Physics:Crystallography|crystallography]], [[Physics:Electromagnetism|electromagnetism]], and [[Chemistry:Metallurgy|metallurgy]].  It is the largest branch of [[Physics:Condensed matter physics|condensed matter physics]]. Solid-state physics studies how the large-scale properties of solid materials result from their [[Physics:Atom|atom]]ic-scale properties.   Thus,  solid-state physics forms a theoretical basis of [[Physics:Materials science|materials science]].  It also has direct applications, for example in the technology of [[Engineering:Transistor|transistor]]s and [[Physics:Semiconductor|semiconductor]]s.}}
{{term|term= '''[[Engineering:Solid solution strengthening|Solid solution strengthening]]'''}}{{defn|defn=Is a type of [[Chemistry:Alloy|alloy]]ing that can be used to improve the [[Physics:Strength of materials|strength]] of a pure metal.<ref name=":0" /> The technique works by adding atoms of one element (the alloying element) to the crystalline lattice of another element (the base metal), forming a [[Physics:Solid solution|solid solution]]. The local nonuniformity in the lattice due to the alloying element makes plastic deformation more difficult by impeding dislocation motion through stress fields. In contrast, alloying beyond the solubility limit can form a second phase, leading to strengthening via other mechanisms (e.g. the [[Engineering:Precipitation hardening|precipitation]] of [[Chemistry:Intermetallic|intermetallic]] compounds).}}
{{term|term= '''[[Chemistry:Solubility|Solubility]]'''}}{{defn|defn=Is the property of a [[Physics:Solid|solid]], [[Physics:Liquid|liquid]] or [[Physics:Gas|gas]]eous [[Chemistry:Chemical substance|chemical substance]] called ''solute'' to dissolve in a solid, liquid or gaseous [[Physics:Solvent|solvent]]. The solubility of a substance fundamentally depends on the [[Physics:Physical property|physical]] and [[Chemistry:Chemical property|chemical properties]] of the solute and solvent as well as on temperature, pressure and presence of other chemicals (including changes to the [[Chemistry:PH|pH]]) of the solution. The extent of the solubility of a substance in a specific solvent is measured as the saturation [[Chemistry:Concentration|concentration]], where adding more solute does not increase the concentration of the solution and begins to precipitate the excess amount of solute.
}}
{{term|term= '''[[Chemistry:Solubility equilibrium|Solubility equilibrium]]'''}}{{defn|defn=Is a type of [[Physics:Dynamic equilibrium|dynamic equilibrium]] that exists when a [[Chemistry:Chemical compound|chemical compound]] in the solid state is in [[Chemistry:Chemical equilibrium|chemical equilibrium]] with a [[Chemistry:Solution|solution]] of that compound. The solid may dissolve unchanged, with dissociation or with chemical reaction with another constituent of the solution, such as acid or alkali. Each solubility equilibrium is characterized by a temperature-dependent ''solubility product'' which functions like an  [[Chemistry:Equilibrium constant|equilibrium constant]]. Solubility equilibria are important in pharmaceutical, environmental and many other scenarios.}}
{{term|term= '''[[Physics:Sound|Sound]]'''}}{{defn|defn=In [[Physics:Physics|physics]], sound is a [[Vibration|vibration]] that propagates as an [[Physics:Acoustic wave|acoustic wave]], through a [[Physics:Transmission medium|transmission medium]] such as a gas, liquid or solid.}}
{{term|term= '''[[Physics:Special relativity|Special relativity]]'''}}{{defn|defn=In [[Physics:Physics|physics]], the '''special theory of relativity''', or '''special relativity''' for short, is a scientific theory regarding the relationship between [[Physics:Spacetime|space and time]]. In [[Biography:Albert Einstein|Albert Einstein]]'s original treatment, the theory is based on two [[Axiom|postulate]]s:<ref>Albert Einstein (1905) "Zur Elektrodynamik bewegter Körper", Annalen der Physik 17: 891; English translation On the Electrodynamics of Moving Bodies by George Barker Jeffery and Wilfrid Perrett (1923); Another English translation On the Electrodynamics of Moving Bodies by Megh Nad Saha (1920).</ref><ref>{{Cite book | last = Griffiths | first = David J. | title = Introduction to Electrodynamics | title-link = Introduction to Electrodynamics | publisher = Pearson | year = 2013 | isbn = 978-0-321-85656-2 | edition = 4th | at = Chapter 12 | chapter =  Electrodynamics and Relativity | author-link = David J. Griffiths}}</ref><ref>{{Cite book | last = Jackson | first = John D. | title = Classical Electrodynamics | title-link = Classical Electrodynamics (book) | publisher = John Wiley & Sons, Inc. | year = 1999 | isbn = 0-471-30932-X | edition = 3rd | at = Chapter 11 |chapter = Special Theory of Relativity | author-link = John David Jackson (physicist)}}</ref>
# The laws of physics are [[Physics:Invariant|invariant]] (that is, identical) in all [[Physics:Inertial frame of reference|inertial frames of reference]] (that is, frames of reference with no [[Physics:Acceleration|acceleration]]).
# The [[Physics:Speed of light|speed of light]] in [[Physics:Vacuum|vacuum]] is the same for all observers, regardless of the motion of the light source or observer.}}
{{term|term= '''[[Physics:Specific heat|Specific heat]]'''}}{{defn|defn=The amount of energy required to change the temperature of a unit mass of substance by one degree.}}
{{term|term= '''[[Physics:Specific gravity|Specific gravity]]'''}}{{defn|defn=The ratio between the mass density of a substance to that of water.}} 
{{term|term= '''[[Specific volume]]'''}}{{defn|defn=The volume of a unit mass of a substance.}}
{{term|term= '''[[Physics:Specific weight|Specific weight]]'''}}{{defn|defn=The weight of a substance per unit volume.}} 
{{term|term= '''[[Physics:Spontaneous combustion|Spontaneous combustion]]'''}}{{defn|defn=Spontaneous combustion or '''spontaneous ignition''' is a type of [[Physics:Combustion|combustion]] which occurs by self-heating (increase in temperature due to [[Physics:Exothermic reaction|exothermic internal reactions]]), followed by [[Astronomy:Thermal runaway|thermal runaway]] (self heating which rapidly accelerates to high temperatures) and finally, autoignition.<ref>{{cite book|last=Babrauskas|first=Vytenis|title=Ignition Handbook|year=2003|publisher=Society of Fire Protection Engineerslocation=Boston p.369|isbn=978-0-9728111-3-2}}</ref>}}
{{term|term= '''[[Physics:Stagnation pressure|Stagnation pressure]]'''}}{{defn|defn=In [[Physics:Fluid dynamics|fluid dynamics]], stagnation pressure (or '''pitot pressure''') is the [[Physics:Static pressure|static pressure]] at a [[Physics:Stagnation point|stagnation point]] in a fluid flow.<ref name=Clancy3.5>Clancy, L.J., ''Aerodynamics'', Section 3.5</ref> At a stagnation point the fluid velocity is zero. In an incompressible flow, stagnation pressure is equal to the sum of the free-stream [[Physics:Static pressure|static pressure]] and the free-stream [[Physics:Dynamic pressure|dynamic pressure]].<ref>[http://scienceworld.wolfram.com/physics/StagnationPressure.html Stagnation Pressure] at Eric Weisstein's World of Physics (Wolfram Research)</ref>}}
{{term|term= '''[[Chemistry:Standard electrode potential|Standard electrode potential]]'''}}{{defn|defn=.}}
{{term|term= '''[[Physics:State of matter|State of matter]]'''}}{{defn|defn=In [[Physics:Physics|physics]], a state of matter is one of the distinct forms in which [[Physics:Matter|matter]] can exist. Four states of matter are observable in everyday life: [[Physics:Solid|solid]], [[Physics:Liquid|liquid]], [[Physics:Gas|gas]], and [[Physics:Plasma|plasma]]. Many intermediate states are known to exist, such as [[Physics:Liquid crystal|liquid crystal]], and some states only exist under extreme conditions, such as [[Physics:Bose–Einstein condensate|Bose–Einstein condensate]]s, [[Physics:Neutron-degenerate matter|neutron-degenerate matter]], and [[Physics:Quark–gluon plasma|quark–gluon plasma]], which only occur, respectively, in situations of extreme cold, extreme density, and extremely high energy. For a complete list of all exotic states of matter, see the [[Physics:List of states of matter|list of states of matter]].}}
{{term|term= '''[[Physics:Statics|Statics]]'''}}{{defn|defn=The study of forces in a non-moving, rigid body.}} 
{{term|term= '''[[Statistics]]'''}}{{defn|defn=Is the discipline that concerns the collection, organization, analysis, interpretation, and presentation of [[Data|data]].<ref name=ox>{{cite web | title=Oxford Reference|url=https://www.oxfordreference.com/view/10.1093/acref/9780199541454.001.0001/acref-9780199541454-e-1566?rskey=nxhBLl&result=1979}}</ref><ref>{{cite encyclopedia |first=Jan-Willem |last=Romijn |year=2014 |title=Philosophy of statistics |encyclopedia=Stanford Encyclopedia of Philosophy |url=http://plato.stanford.edu/entries/statistics/}}</ref><ref>{{cite web | title=Cambridge Dictionary | url=https://dictionary.cambridge.org/dictionary/english/statistics}}</ref> In applying statistics to a scientific, industrial, or social problem, it is conventional to begin with a [[Statistical population|statistical population]] or a [[Statistical model|statistical model]] to be studied. Populations can be diverse groups of people or objects such as "all people living in a country" or "every atom composing a crystal". Statistics deals with every aspect of data, including the planning of data collection in terms of the design of surveys and experiments.<ref name=Dodge>Dodge, Y. (2006) ''The Oxford Dictionary of Statistical Terms'', Oxford University Press. {{isbn|0-19-920613-9}}</ref>}}
{{term|term= '''Steam table'''}}{{defn|defn=Thermodynamic data table containing steam or water properties .<ref>[https://www.chegg.com/homework-help/definitions/steam-tables-5 Chegg Study chegg.com] Retrieved August 2021</ref>}}
{{term|term= '''[[Physics:Stefan–Boltzmann law|Stefan–Boltzmann law]]'''}}{{defn|defn=The Stefan–Boltzmann law describes the power radiated from a [[Astronomy:Black body|black body]] in terms of its [[Physics:Thermodynamic temperature|temperature]].  Specifically, the Stefan–Boltzmann law states that the total [[Physics:Energy|energy]] radiated per unit [[Area|surface area]] of a [[Astronomy:Black body|black body]] across [[Astronomy:Black-body radiation#Spectrum|all wavelengths]] per unit [[Time|time]] <math> j^{\star}</math> (also known as the black-body ''radiant emittance'') is directly [[Proportionality (mathematics)|proportional]] to the fourth power of the black body's [[Physics:Thermodynamic temperature|thermodynamic temperature]] ''T'':

:<math> j^{\star} = \sigma T^{4}.</math>

The constant of proportionality ''σ'', called the [[Physics:Stefan–Boltzmann constant|Stefan–Boltzmann constant]], is derived from other known [[Physics:Physical constant|physical constant]]s. [[2019 redefinition of the SI base units|Since 2019]], the value of the constant is

:<math>
\sigma=\frac{2\pi^5 k^4}{15c^2h^3} = 5.670374\ldots\times 10^{-8}\, \mathrm{W\, m^{-2}\,K^{-4}},
</math>

where ''k'' is the [[Physics:Boltzmann constant|Boltzmann constant]], ''h'' is Planck's constant, and ''c'' is [[Physics:Speed of light|the speed of light in a vacuum]]. The [[Physics:Radiance|radiance]] from a specified angle of view (watts per square metre per [[Steradian|steradian]]) is given by
:<math> L = \frac{j^{\star}}\pi = \frac\sigma\pi T^{4}.</math>

A body that does not absorb all incident radiation (sometimes known as a grey body) emits less total energy than a black body and is characterized by an [[Physics:Emissivity|emissivity]], <math>\varepsilon < 1</math>:

:<math> j^{\star} = \varepsilon\sigma T^{4}.</math>

The radiant emittance <math> j^{\star}</math> has [[Dimensional analysis#Definition|dimensions]] of [[Physics:Energy flux|energy flux]] (energy per unit time per unit area), and the SI units of measure are [[Joule|joule]]s per second per square metre, or equivalently, [[Watt|watt]]s per square metre. The SI unit for absolute temperature ''T'' is the [[Kelvin|kelvin]].  ''<math>\varepsilon</math>'' is the [[Physics:Emissivity|emissivity]] of the grey body; if it is a perfect blackbody, <math>\varepsilon=1</math>. In the still more general (and realistic) case, the emissivity depends on the wavelength, <math>\varepsilon=\varepsilon(\lambda)</math>.

To find the total [[Physics:Power|power]] radiated from an object, multiply by its surface area, <math>A</math>:

:<math> P= A j^{\star} = A \varepsilon\sigma T^{4}.</math>

Wavelength- and subwavelength-scale particles,<ref name="Bohren">
{{cite book
 |last1=Bohren |first1=Craig F.
 |last2=Huffman |first2=Donald R.
 |year=1998
 |title=Absorption and scattering of light by small particles
 |url=https://books.google.com/books?id=ib3EMXXIRXUC
 |publisher=Wiley
 |isbn=978-0-471-29340-8
 |pages=123–126
}}</ref> [[Physics:Metamaterial|metamaterial]]s,<ref>
{{Cite book
 |last1=Narimanov |first1=Evgenii E.
 |last2=Smolyaninov |first2=Igor I.
 |year=2012
 |chapter=Beyond Stefan–Boltzmann Law: Thermal Hyper-Conductivity
 |title=Conference on Lasers and Electro-Optics 2012
 |series=OSA Technical Digest
 |publisher=Optical Society of America
 |pages=QM2E.1
 |doi=10.1364/QELS.2012.QM2E.1
 |isbn=978-1-55752-943-5
|citeseerx=10.1.1.764.846
 |s2cid=36550833
 }}</ref> and other nanostructures are not subject to ray-optical limits and may be designed to exceed the Stefan–Boltzmann law.}}
{{term|term= '''[[Stewart platform]]'''}}{{defn|defn=Is a type of parallel manipulator that has six [[Physics:Prismatic joint|prismatic actuators]], commonly [[Engineering:Hydraulic jack|hydraulic jack]]s or electric [[Physics:Linear actuator|linear actuator]]s, attached in pairs to three positions on the platform's baseplate, crossing over to three mounting points on a top plate. All 12 connections are made via [[Engineering:Universal joint|universal joint]]s. Devices placed on the top plate can be moved in the [[Physics:Six degrees of freedom|six degrees of freedom]] in which it is possible for a freely-suspended body to move: three linear movements x, y, z (lateral, longitudinal, and vertical), and the three rotations (pitch, roll, and yaw).}} 
{{term|term= '''[[Physics:Stiffness|Stiffness]]'''}}{{defn|defn=Is the extent to which an object resists [[Physics:Deformation (mechanics)|deformation]] in response to an applied [[Physics:Force|force]].<ref>{{cite journal
| title = Stiffness--an unknown world of mechanical science?
| journal = Injury
| author = Baumgart F.
| year = 2000
| volume = 31
| pages = 14–84
| publisher = Elsevier
| quote = “Stiffness” = “Load” divided by “Deformation”
| doi=10.1016/S0020-1383(00)80040-6}}</ref>

The complementary concept is '''flexibility''' or pliability: the more flexible an object is, the less stiff it is.<ref>{{citation |page=126 |chapter=Stiffness and flexibility |title=200 science investigations for young students |author=Martin Wenham |year=2001 |isbn=978-0-7619-6349-3}}</ref>}}
{{term|term= '''[[Chemistry:Stoichiometry|Stoichiometry]]'''}}{{defn|defn=Refers to the relationship between the quantities of reactants and [[Chemistry:Product|products]] before, during, and following [[Chemistry:Chemical reaction|chemical reaction]]s.

Stoichiometry is founded on the law of conservation of mass where the total mass of the reactants equals the total mass of the products, leading to the insight that the relations among quantities of reactants and products typically form a ratio of positive integers.   This means that if the amounts of the separate reactants are known, then the amount of the product can be calculated. Conversely, if one reactant has a known quantity and the quantity of the products can be empirically determined, then the amount of the other reactants can also be calculated.}}
{{term|term= '''[[Physics:Deformation (mechanics)|Strain]]'''}}{{defn|defn=.}}
{{term|term= '''[[Engineering:Work hardening|Strain hardening]]'''}}{{defn|defn='''Work hardening''', also known as strain hardening, is the [[Physics:Strength of materials|strengthening]] of a metal or polymer by plastic deformation. Work hardening may be desirable, undesirable, or inconsequential, depending on the context.

This strengthening occurs because of dislocation movements and dislocation generation within the [[Chemistry:Crystal structure|crystal structure]] of the material.<ref>{{harvnb|Degarmo|Black|Kohser|2003|p=60}}.</ref> Many non-brittle metals with a reasonably high [[Physics:Melting point|melting point]] as well as several polymers can be strengthened in this fashion.<ref>{{Citation|last=Van Melick|first=H. G. H.|last2= Govaert|first2=L. E.|last3=Meijer|first3=H. E. H.|year=2003|title= On the origin of strain hardening in glassy polymers|journal= Polymer|volume=44|number=8|pages= 2493–2502|doi=10.1016/s0032-3861(03)00112-5}}</ref> Alloys not amenable to heat treatment, including low-carbon steel, are often work-hardened. Some materials cannot be work-hardened at low temperatures, such as [[Chemistry:Indium|indium]],<ref>{{Citation|last=Swenson|first= C. A.|year=1955|title=Properties of Indium and Thallium at low temperatures|journal=Physical Review|volume=100|number=6|pages=1607–1614|doi=10.1103/physrev.100.1607}}</ref> however others can be strengthened only via work hardening, such as pure copper and aluminum.<ref>{{harvnb|Smith|Hashemi|2006|p=246}}.</ref>}}
{{term|term= '''[[Physics:Strength of materials|Strength of materials]]'''}}{{defn|defn=The field of strength of materials, also called '''mechanics of materials''', typically refers to various methods of calculating the [[Physics:Stress|stresses]] and strains in structural members, such as beams, columns, and shafts. The methods employed to predict the response of a structure under loading and its susceptibility to various failure modes takes into account the properties of the materials such as its yield strength, ultimate strength, [[Physics:Young's modulus|Young's modulus]], and [[Physics:Poisson's ratio|Poisson's ratio]]. In addition, the mechanical element's macroscopic properties (geometric properties) such as its length, width, thickness, boundary constraints and abrupt changes in geometry such as holes are considered.}}
{{term|term= '''[[Physics:Stress (mechanics)|Stress]]'''}}{{defn|defn=In [[Physics:Continuum mechanics|continuum mechanics]], stress is a [[Physics:Physical quantity|physical quantity]] that expresses the internal [[Physics:Force|force]]s that neighbouring [[Physics:Particle|particle]]s of a continuous material exert on each other, while [[Physics:Deformation (mechanics)#Strain|strain]] is the measure of the deformation of the material. For example, when a [[Physics:Solid|solid]] vertical bar is supporting an overhead [[Physics:Weight|weight]], each particle in the bar pushes on the particles immediately below it. When a [[Physics:Liquid|liquid]] is in a closed container under [[Physics:Pressure|pressure]], each particle gets pushed against by all the surrounding particles.  The container walls and the [[Physics:Pressure|pressure]]-inducing surface (such as a piston) push against them in (Newtonian) reaction. These macroscopic forces are actually the net result of a very large number of [[Physics:Intermolecular force|intermolecular force]]s and [[Physics:Statistical mechanics|collision]]s between the particles in those [[Physics:Molecule|molecule]]s. Stress is frequently represented by a lowercase Greek letter sigma (''σ'').}}
{{term|term= '''[[Stress–strain analysis]]'''}}{{defn|defn=Stress–strain analysis (or '''stress analysis''') is an [[Engineering:Engineering|engineering]] discipline that uses many methods to determine the [[Physics:Stress (mechanics)|stresses]] and [[Physics:Strain (mechanics)|strains]] in materials and structures subjected to [[Physics:Force|force]]s. In [[Physics:Continuum mechanics|continuum mechanics]], stress is a [[Physics:Physical quantity|physical quantity]] that expresses the internal [[Physics:Force|force]]s that neighboring [[Physics:Particle|particle]]s of a [[Physics:Continuum mechanics|continuous material]] exert on each other, while strain is the measure of the deformation of the material.

In simple terms we can define stress as the force of resistance per unit per unit area, offered by a body against deformation. Stress is the ratio of force over area (S =R/A, where S is the stress, R is the internal resisting force and A is the cross-sectional area). Strain is the ratio of change in length to the original length, when a given body is subjected to some external force (Strain= change in length÷the original length).}}
{{term|term= '''[[Physics:Stress–strain curve|Stress–strain curve]]'''}}{{defn|defn=In engineering and [[Physics:Materials science|materials science]], a stress–strain curve for a material gives the relationship between [[Physics:Stress (mechanics)|stress]] and [[Physics:Deformation#Strain|strain]]. It is obtained by gradually applying [[Structural load|load]] to a test coupon and measuring the [[Engineering:Deformation (engineering)|deformation]], from which the stress and strain can be determined (see [[Engineering:Tensile testing|tensile testing]]). These curves reveal many of the [[Chemistry:List of materials properties|properties of a material]], such as the [[Physics:Young's modulus|Young's modulus]], the yield strength and the [[Physics:Ultimate tensile strength|ultimate tensile strength]].}}
{{term|term= '''[[Structural analysis]]'''}}{{defn|defn=Is the determination of the effects of [[Structural load|load]]s on physical [[Structure|structure]]s and their [[Engineering:Structural engineering#Structural elements|components]].
Structures subject to this type of [[Philosophy:Analysis|analysis]] include all that must withstand loads, such as buildings, bridges, aircraft and ships.  Structural analysis employs the fields of [[Physics:Applied mechanics|applied mechanics]], [[Physics:Materials science|materials science]] and [[Applied mathematics|applied mathematics]] to compute a structure's [[Engineering:Deformation (engineering)|deformation]]s, internal [[Physics:Force|force]]s, stresses, support reactions, accelerations, and [[Structural stability|stability]]. The results of the analysis are used to verify a structure's fitness for use, often precluding [[Engineering:Physical test|physical test]]s. Structural analysis is thus a key part of the [[Engineering:Structural engineering|engineering design of structures]].<ref>[https://www.sciencedirect.com/topics/engineering/structural-analysis "Science Direct: Structural Analysis"] {{webarchive|url=https://web.archive.org/web/20210516014830/https://www.sciencedirect.com/topics/engineering/structural-analysis |date=2021-05-16 }}</ref>}} 
{{term|term= '''[[Structural load]]'''}}{{defn|defn=A structural load or '''structural action''' is a [[Physics:Force|force]], [[Engineering:Deformation (engineering)|deformation]], or [[Physics:Acceleration|acceleration]] applied to [[Engineering:Structural engineering#Structural elements|structural elements]].<ref>{{cite book|title=ASCE/SEI 7-05 Minimum Design Loads for Buildings and Other Structures|year=2006|publisher=American Society of Civil Engineers|isbn=0-7844-0809-2|pages=1}}</ref><ref>{{cite book|title=Eurocode 0: Basis of structural design EN 1990 |year=2002|publisher=European Committee for Standardization|location=Bruxelles|chapter=1.5.3.1}}</ref> A load causes [[Physics:Stress|stress]], [[Engineering:Deformation (engineering)|deformation]], and [[Displacement (vector)|displacement]] in a [[Structure|structure]]. [[Structural analysis]], a discipline in [[Engineering:Engineering|engineering]], analyzes the effects loads on structures and structural elements. Excess load may cause structural failure, so this should be considered and controlled during the design of a structure. Particular  mechanical structures—such as [[Engineering:Aircraft|aircraft]], [[Astronomy:Satellite|satellite]]s, [[Engineering:Rocket|rocket]]s, space stations, ships, and [[Engineering:Submarine|submarine]]s—are subject to their own particular structural loads and actions.<ref>{{cite book|title=Mark's Standard Handbook for Mechanical Engineers|publisher=McGraw-Hill|isbn=0-07-004997-1|edition=10th|editor=Avallone, E.A. |editor2= Baumeister, T.|pages=11–42}}</ref> Engineers often evaluate structural loads based upon published [[Finance:Regulation|regulation]]s, [[Finance:Contract|contract]]s, or specifications.  Accepted [[Technical standard|technical standard]]s are used for [[Acceptance testing|acceptance testing]] and inspection.}}
{{term|term= '''[[Sublimation (phase transition)|Sublimation]]'''}}{{defn|defn=Is the transition of a substance directly from the [[Physics:Solid|solid]] to the [[Physics:Gas|gas]] state,<ref>{{cite Merriam-Webster|Sublimate}}</ref> without passing through the liquid state.<ref>{{cite book |last1=Whitten |first1=Kenneth W. |last2=Gailey |first2=Kenneth D. |last3=Davis |first3=Raymond E. |title=General chemistry |url=https://archive.org/details/generalchemistry00whit_0 |url-access=registration |date=1992 |publisher=Saunders College Publishing |isbn=0-03-072373-6 |page=[https://archive.org/details/generalchemistry00whit_0/page/475 475] |edition=4th}}</ref> Sublimation is an [[Physics:Endothermic process|endothermic process]] that occurs at temperatures and pressures below a substance's [[Chemistry:Triple point|triple point]] in its [[Phase diagram|phase diagram]], which corresponds to the lowest pressure at which the substance can exist as a liquid. The reverse process of sublimation is [[Physics:Deposition (phase transition)|deposition]] or desublimation, in which a substance passes directly from a gas to a solid phase.<ref name="DepositionDef">{{cite journal |title=Controlling condensation and frost growth with chemical micropatterns |first=Jonathan B. |last=Boreyko |first2=Ryan R. |last2=Hansen |first3=Kevin R. |last3=Murphy |first4=Saurabh |last4=Nath |first5=Scott T. |last5=Retterer |first6=C. Patrick |last6=Collier |journal=Scientific Reports |year=2016 |volume=6 |pages=19131 |doi=10.1038/srep19131 |pmid=26796663 |pmc=4726256 |bibcode=2016NatSR...619131B}}</ref> Sublimation has also been used as a generic term to describe a solid-to-gas transition (sublimation) followed by a gas-to-solid transition ([[Physics:Deposition (phase transition)|deposition]]).<ref>{{Dictionary.com|Sublime}}</ref> While [[Physics:Vaporization|vaporization]] from liquid to gas occurs as [[Physics:Evaporation|evaporation]] from the surface if it occurs below the boiling point of the liquid, and as [[Physics:Boiling|boiling]] with formation of bubbles in the interior of the liquid if it occurs at the boiling point, there is no such distinction for the solid-to-gas transition which always occurs as sublimation from the surface.}}
{{term|term= '''[[Subsumption architecture]]'''}}{{defn|defn=Is a reactive robotic architecture heavily associated with [[Engineering:Behavior-based robotics|behavior-based robotics]] which was very popular in the 1980s and 90s.  The term was introduced by [[Biography:Rodney Brooks|Rodney Brooks]] and colleagues in 1986.<ref name=Brooks1986a>{{cite journal
 | doi = 10.1109/JRA.1986.1087032
 | author = Brooks, R.
 | year = 1986
 | title = A robust layered control system for a mobile robot
 | journal = IEEE Journal of Robotics and Automation
 | volume = 2
 | issue = 1
 | pages = 14–23
 | hdl = 1721.1/6432
 | hdl-access = free
 }}</ref><ref name=Brooks1986b>{{cite conference
 | author = Brooks, R.
 | year = 1986
 | title = Asynchronous distributed control system for a mobile robot.
 | book-title = SPIE Conference on Mobile Robots
 | pages = 77–84
 | url = http://www.csa.com/partners/viewrecord.php?requester=gs&collection=TRD&recid=1481881CI
}}</ref><ref>Brooks, R. A., "A Robust Programming Scheme for a Mobile Robot", Proceedings of NATO Advanced Research Workshop on Languages for Sensor-Based Control in Robotics, Castelvecchio Pascoli, Italy, September 1986.</ref>  Subsumption has been widely influential in autonomous robotics and elsewhere in [[Real-time computing|real-time]] [[Artificial intelligence|AI]].}} 
{{term|term= '''[[Physics:Surface tension|Surface tension]]'''}}{{defn|defn=Is the tendency of [[Physics:Liquid|liquid]] surfaces at rest to shrink into the minimum [[Surface area|surface area]] possible. Surface tension is what allows objects with a higher density than water to float on a water surface without becoming even partly submerged.}}
{{term|term= '''[[Physics:Superconductivity|Superconductivity]]'''}}{{defn|defn=Is a set of physical properties observed in certain materials where [[Physics:Electrical resistance and conductance|electrical resistance]] vanishes and [[Physics:Magnetic field|magnetic flux fields]] are expelled from the material. Any material exhibiting these properties is a '''superconductor'''. Unlike an ordinary metallic [[Physics:Electrical conductor|conductor]], whose resistance decreases gradually as its temperature is lowered even down to near [[Physics:Absolute zero|absolute zero]], a superconductor has a characteristic [[Physics:Phase transition|critical temperature]] below which the resistance drops abruptly to zero. An [[Physics:Electric current|electric current]] through a loop of [[Physics:Superconducting wire|superconducting wire]] can persist indefinitely with no power source.<ref>{{cite book
  | author =John Bardeen
  | author2 = Leon Cooper
  | author3 = J. R. Schriffer
  | title = Theory of Superconductivity
  | journal = Physical Review
  | volume = 108
  | issue = 5
  | pages = 1175
  | date = December 1, 1957
  | url = https://books.google.com/books?id=_QKPGDG-cuAC&q=%22persist+indefinitely&pg=PA76
  | doi = 10.1103/physrev.108.1175
  | access-date = June 6, 2014|bibcode = 1957PhRv..108.1175B | isbn = 978-0-677-00080-0
  }} reprinted in Nikolaĭ Nikolaevich Bogoliubov (1963) ''The Theory of Superconductivity, Vol. 4'', CRC Press, {{ISBN|0677000804}}, p. 73</ref><ref name="Daintith">{{cite book
 | author = John Daintith
 | title = The Facts on File Dictionary of Physics
 | publisher = Infobase Publishing
 | edition = 4th
 | date = 2009
 | pages = 238
 | url = https://books.google.com/books?id=VdEVdJo3CDgC&pg=PA238
 | isbn = 978-1-4381-0949-7  }}</ref><ref name="Gallop">{{cite book
 |author=John C. Gallop
 |date=1990
 |title=SQUIDS, the Josephson Effects and Superconducting Electronics
 |url=https://books.google.com/books?id=ad8_JsfCdKQC
 |publisher=CRC Press
 |pages=1, 20
 |isbn=978-0-7503-0051-3
}}</ref><ref name="Durrant">{{cite book
 | last1 = Durrant
 | first1 = Alan
 | title = Quantum Physics of Matter
 | publisher = CRC Press
 | date = 2000
 | pages = 102–103
 | url = https://books.google.com/books?id=F0JmHRkJHiUC&q=%22persist+indefinitely&pg=PA103
 | isbn = 978-0-7503-0721-5 }}</ref>}}
{{term|term= '''[[Chemistry:Superhard material|Superhard material]]'''}}{{defn|defn=Is a material with a hardness value exceeding 40 gigapascals (GPa) when measured by the [[Physics:Vickers hardness test|Vickers hardness test]].<ref>{{cite journal|last1=Wentorf|first1=R. H.|last2=Devries|first2=R. C.|last3=Bundy|first3=F. P.|title=Sintered Superhard Materials|journal=Science|volume=208|pages=873–80|date=1980|doi=10.1126/science.208.4446.873|issue=4446|pmid=17772811|s2cid=34588568}}</ref><ref>Fischer-Cripps, Anthony C. (2004) [https://books.google.com/books?id=YArOm3wI9xQC&pg=PA198 Nanoindentation]. Springer. {{ISBN|0-387-22045-3}}. p. 198</ref><ref>Veprek, S.; Zeer, A. and Riedel, R. (2000) in ''Handbook of Ceramic Hard
Materials'', R. Riedel (ed.). Wiley, Weinheim. {{ISBN|3-527-29972-6}}</ref><ref name=d1>{{cite journal|last1=Dubrovinskaia|first1=N.|last2=Dubrovinsky|first2=L.|last3=Solozhenko|first3=V. L.|title=Comment on "Synthesis of Ultra-Incompressible Superhard Rhenium Diboride at Ambient Pressure"|journal=Science|volume=318|pages=1550c|date=2007|doi=10.1126/science.1147650|issue=5856|bibcode = 2007Sci...318.1550D|pmid=18063772|doi-access=free}}</ref> They are virtually incompressible solids with high electron density and high [[Chemistry:Covalent bond|bond covalency]]. As a result of their unique properties, these materials are of great interest in many industrial areas including, but not limited to, [[Engineering:Abrasive|abrasive]]s, polishing and [[Engineering:Cutting tool (machining)|cutting tools]], [[Engineering:Disc brake|disc brake]]s, and [[Physics:Wear|wear]]-resistant and protective coatings.}}
{{term|term= '''[[Physics:Supersaturation|Supersaturation]]'''}}{{defn|defn=Supersaturation occurs with a chemical solution when the concentration of a solute exceeds the concentration specified by the value equilibrium [[Chemistry:Solubility|solubility]]. Most commonly the term is applied to a solution of a solid in a liquid. A supersaturated solution is in a metastable state; it may be brought to equilibrium by forcing the excess of solute to separate from the solution. The term can also  be applied to a mixture of gases.}}
{{glossary end}}

==T==
{{glossary}}
{{term|term= '''[[Physics:Acceleration#Tangential and centripetal acceleration|Tangential acceleration]]'''}}{{defn|defn=The velocity of a particle moving on a curved path as a [[Function (mathematics)|function]] of time can be written as:
:<math>\mathbf{v}(t) = v(t) \frac{\mathbf{v}(t)}{v(t)} = v(t) \mathbf{u}_\mathrm{t}(t) , </math>

with ''v''(''t'') equal to the speed of travel along the path, and

:<math>\mathbf{u}_\mathrm{t} = \frac{\mathbf{v}(t)}{v(t)} \ , </math>

a [[Differential geometry of curves#Tangent vector|unit vector tangent]] to the path pointing in the direction of motion at the chosen moment in time. Taking into account both the changing speed ''v''(''t'') and the changing direction of '''u'''<sub>''t''</sub>, the acceleration of a particle moving on a curved path can be written using the [[Chain rule|chain rule]] of differentiation<ref>{{cite web|last1=Weisstein|first1=Eric W.|title=Chain Rule| url=http://mathworld.wolfram.com/ChainRule.html|website=Wolfram MathWorld| publisher=Wolfram Research| access-date=2 August 2016}}</ref> for the product of two functions of time as:

:<math>\begin{alignat}{3}
\mathbf{a} & = \frac{d \mathbf{v}}{dt} \\
           & =  \frac{dv}{dt} \mathbf{u}_\mathrm{t} +v(t)\frac{d \mathbf{u}_\mathrm{t}}{dt} \\
           & = \frac{dv }{dt} \mathbf{u}_\mathrm{t}+ \frac{v^2}{r}\mathbf{u}_\mathrm{n}\ ,
\end{alignat}</math>

where '''u'''<sub>n</sub> is the  unit (inward) [[Differential geometry of curves#Normal or curvature vector|normal vector]] to the particle's trajectory (also called ''the principal normal''), and '''r''' is its instantaneous [[Curvature#Curvature of plane curves|radius of curvature]] based upon the [[Osculating circle#Mathematical description|osculating circle]] at time ''t''. These components are called the tangential acceleration and the normal or radial acceleration (or centripetal acceleration in circular motion, see also [[Physics:Circular motion|circular motion]] and [[Physics:Centripetal force|centripetal force]]).

Geometrical analysis of three-dimensional space curves, which explains tangent, (principal) normal and binormal, is described by the [[Frenet–Serret formulas]].<ref name = Andrews>{{cite book |title = Mathematical Techniques for Engineers and Scientists |author1=Larry C. Andrews |author2=Ronald L. Phillips |page = 164 |url = https://books.google.com/books?id=MwrDfvrQyWYC&q=particle+%22planar+motion%22&pg=PA164
|isbn = 978-0-8194-4506-3 |publisher = SPIE Press |year = 2003  }}</ref><ref name = Chand>{{cite book |title = Applied Mathematics |page = 337 |author1=Ch V Ramana Murthy |author2=NC Srinivas |isbn = 978-81-219-2082-7|url = https://books.google.com/books?id=Q0Pvv4vWOlQC&pg=PA337|publisher = S. Chand & Co. | year = 2001| location=New Delhi }}</ref>}}
{{term|term= '''[[Technical standard]]'''}}{{defn|defn=A technical standard is an established norm or [[Requirement|requirement]] for a repeatable technical task. It is usually a formal document that establishes uniform engineering or technical criteria, methods, processes, and practices. In contrast, a custom, [[Philosophy:Convention (norm)|convention]], company product, corporate standard, and so forth that becomes generally accepted and dominant is often called a [[Engineering:De facto standard|''de facto'' standard]].}}
{{term|term= '''[[Physics:Temperature|Temperature]]'''}}{{defn|defn=Is a physical quantity that expresses hot and cold. It is the manifestation of [[Physics:Thermal energy|thermal energy]], present in all matter, which is the source of the occurrence of [[Physics:Heat|heat]], a flow of energy, when a body is in contact with another that is colder. Temperature is [[Measurement|measured]] with a [[Physics:Thermometer|thermometer]]. Thermometers are calibrated in various [[Conversion of units of temperature|temperature scales]] that historically have used various reference points and thermometric substances for definition. The most common scales are the [[Celsius|Celsius scale]] (formerly called ''centigrade'', denoted °C), the [[Fahrenheit|Fahrenheit scale]] (denoted °F), and the [[Kelvin|Kelvin scale]] (denoted K), the last of which is predominantly used for scientific purposes by conventions of the [[International System of Units]] (SI). }} 
{{term|term= '''[[Engineering:Tempering (metallurgy)|Tempering (metallurgy)]]'''}}{{defn|defn=Heat treatment to alter the crystal structure of a metal such as steel.}}
{{term|term= '''Tensile force'''}}{{defn|defn=Pulling force, tending to lengthen an object.}}
{{term|term= '''Tensile modulus'''}}{{defn|defn=''Young's modulus'' <math>E</math>, the ''Young modulus'', or the modulus of elasticity in tension, is a mechanical property that measures the tensile [[Physics:Stiffness|stiffness]] of a [[Physics:Solid|solid]] material. It quantifies the relationship between tensile [[Physics:Stress (mechanics)|stress]] <math>\sigma</math> (force per unit area) and axial [[Physics:Strain (mechanics)|strain]] <math>\varepsilon</math> (proportional deformation) in the [[Physics:Linear elasticity|linear elastic]] region of a material and is determined using the formula:<ref>{{cite book |title=Nature and Properties of Engineering Materials |first=D. |last=Jastrzebski |publisher=John Wiley & Sons, Inc |edition=Wiley International |year=1959}}</ref>
<math display="block">E = \frac{\sigma}{\varepsilon}</math>

Young's moduli are typically so large that they are expressed not in [[Pascal (unit)|pascals]] but in gigapascals (GPa).}}
{{term|term= '''[[Physics:Tensile strength|Tensile strength]]'''}}{{defn|defn=Ultimate tensile strength (UTS), often shortened to tensile strength (TS), ultimate strength, or <math>F_\text{tu}</math> within equations,<ref name="stressebook.com">{{cite web|url=http://www.stressebook.com/mmpds-mechanical-properties-table/|title=Generic MMPDS Mechanical Properties Table|date=6 December 2014|website=stressebook.com|access-date=27 April 2018|url-status=live|archive-url=https://web.archive.org/web/20171201200651/http://www.stressebook.com/mmpds-mechanical-properties-table/|archive-date=1 December 2017|df=dmy-all}}</ref><ref name="Degarmo 2003 31">{{harvnb|Degarmo|Black|Kohser|2003|p=31}}</ref><ref name="Smith 2006 223">{{harvnb|Smith|Hashemi|2006|p=223}}</ref> is the maximum [[Physics:Stress (mechanics)|stress]] that a material can withstand while being stretched or pulled before breaking. In brittle materials the ultimate tensile strength is close to the yield point, whereas in ductile materials the ultimate tensile strength can be higher.}}
{{term|term= '''[[Engineering:Tensile testing|Tensile testing]]'''}}{{defn|defn=Tensile testing, also known as tension testing,<ref>{{cite book|last = Czichos|first = Horst|title = Springer Handbook of Materials Measurement Methods|publisher = Springer|location = Berlin|year = 2006|pages = 303–304|url = https://books.google.com/books?id=8lANaR-Pqi4C|isbn = 978-3-540-20785-6}}</ref> is a fundamental [[Physics:Materials science|materials science]] and [[Engineering:Engineering|engineering]] test in which a sample is subjected to a controlled [[Physics:Tension|tension]] until failure. Properties that are directly measured via a tensile test are [[Physics:Ultimate tensile strength|ultimate tensile strength]], breaking strength, maximum elongation and reduction in area.<ref name="davis1">{{cite book|last = Davis|first = Joseph R.|title = Tensile testing|publisher = ASM International|year = 2004|edition = 2nd|url = https://books.google.com/books?id=5uRIb3emLY8C|isbn = 978-0-87170-806-9}}</ref> From these measurements the following properties can also be determined: [[Physics:Young's modulus|Young's modulus]], [[Physics:Poisson's ratio|Poisson's ratio]], yield strength, and strain-hardening characteristics.<ref>{{harvnb|Davis|2004|p=33}}.</ref> ''Uniaxial tensile testing'' is the most commonly used for obtaining the mechanical characteristics of [[Isotropy|isotropic]] materials. Some materials use ''biaxial tensile testing''. The main difference between these testing machines being how load is applied on the materials.}}
{{term|term= '''Tension member'''}}{{defn|defn=Tension members are structural elements that are subjected to axial tensile forces. Examples of tension members are bracing for buildings and [[Engineering:Bridge|bridge]]s, [[Physics:Truss|truss]] members, and [[Engineering:Wire rope|cable]]s in suspended [[Engineering:Roof|roof]] systems.}}
{{term|term= '''[[Physics:Thermal conduction|Thermal conduction]]'''}}{{defn|defn=Is the transfer of [[Physics:Internal energy|internal energy]] by microscopic collisions of particles and movement of electrons within a body. The colliding particles, which include molecules, atoms and electrons, transfer disorganized microscopic kinetic and potential energy, jointly known as internal energy. Conduction takes place in all [[Physics:Phase (matter)|phases]]: solid, liquid, and gas.}}
{{term|term= '''[[Physics:Thermal equilibrium|Thermal equilibrium]]'''}}{{defn|defn=Two [[Physics:Physical system|physical system]]s are in thermal equilibrium if there is no net flow of thermal energy between them when they are connected by a path permeable to heat.  Thermal equilibrium obeys the [[Physics:Zeroth law of thermodynamics|zeroth law of thermodynamics]].  A system is said to be in thermal equilibrium with itself if the temperature within the system is spatially uniform and temporally constant.

Systems in [[Physics:Thermodynamic equilibrium|thermodynamic equilibrium]] are always in thermal equilibrium, but the converse is not always true.  If the connection between the systems allows transfer of energy as 'change in [[Physics:Internal energy|internal energy]]' but does not allow transfer of matter or transfer of energy as [[Physics:Work|work]], the two systems may reach thermal equilibrium without reaching thermodynamic equilibrium.}}
{{term|term= '''[[Physics:Thermal radiation|Thermal radiation]]'''}}{{defn|defn=Is [[Physics:Electromagnetic radiation|electromagnetic radiation]] generated by the thermal motion of particles in [[Physics:Matter|matter]]. All matter with a [[Physics:Temperature|temperature]] greater than [[Physics:Absolute zero|absolute zero]] emits thermal radiation. Particle motion results in [[Physics:Larmor formula|charge-acceleration]] or [[Physics:Dipole|dipole]] oscillation which produces electromagnetic radiation.}}
{{term|term= '''[[Physics:Thermodynamics|Thermodynamics]]'''}}{{defn|defn=Is a branch of [[Physics:Physics|physics]] that deals with [[Physics:Heat|heat]], [[Physics:Work (thermodynamics)|work]], and [[Physics:Temperature|temperature]], and their relation to [[Physics:Energy|energy]], [[Physics:Radiation|radiation]], and physical properties of [[Physics:Matter|matter]]. The behavior of these quantities is governed by the four [[Physics:Laws of thermodynamics|laws of thermodynamics]] which convey a quantitative description using measurable macroscopic [[Physics:Physical quantity|physical quantities]], but may be explained in terms of microscopic constituents by [[Physics:Statistical mechanics|statistical mechanics]]. Thermodynamics applies to a wide variety of topics in [[Science|science]] and [[Engineering:Engineering|engineering]], especially [[Chemistry:Physical chemistry|physical chemistry]], [[Biology:Biochemistry|biochemistry]], [[Chemistry:Chemical engineering|chemical engineering]] and [[Engineering:Mechanical engineering|mechanical engineering]], but also in other complex fields such as [[Physics:Meteorology|meteorology]].}}
{{term|term= '''[[Physics:Theory of relativity|Theory of relativity]]'''}}{{defn|defn=Usually encompasses two interrelated theories by [[Biography:Albert Einstein|Albert Einstein]]: [[Physics:Special relativity|special relativity]] and [[Physics:General relativity|general relativity]], proposed and published in 1905 and 1915, respectively.<ref>{{Citation |author=Einstein A. |date=1916 |type=Translation 1920 |title=Relativity: The Special and General Theory|publisher=H. Holt and Company|location=New York|title-link=s:Relativity: The Special and General Theory }}</ref> Special relativity applies to all physical phenomena in the absence of [[Physics:Gravity|gravity]]. General relativity explains the law of gravitation and its relation to other forces of nature.<ref>Einstein, Albert (November 28, 1919). [[Physics:Theory of relativity#cite note-londontimes-2|"Time, Space, and Gravitation"]] . The Times.</ref> It applies to the cosmological and astrophysical realm, including astronomy.<ref>Will, Clifford M (2010). "Relativity". Grolier Multimedia Encyclopedia. Retrieved 2010-08-01.</ref>}}
{{term|term= '''[[Engineering:Thévenin's theorem|Thévenin's theorem]]'''}}{{defn|defn=.}}
{{term|term= '''[[Physics:Three-phase electric power|Three-phase electric power]]'''}}{{defn|defn=Is a common method of [[Physics:Alternating current|alternating current]] [[Physics:Electric power|electric power]] [[Engineering:Electricity generation|generation]], [[Finance:Electric power transmission|transmission]], and [[Engineering:Electric power distribution|distribution]].<ref>William D. Stevenson, Jr. ''Elements of Power System Analysis Third Edition'', McGraw-Hill, New York (1975). {{ISBN|0-07-061285-4}}, p. 2</ref> It is a type of polyphase system and is the most common method used by [[Engineering:Electrical grid|electrical grid]]s worldwide to transfer power. It is also used to power large [[Physics:Electric motor|motors]] and other heavy loads.}}
{{term|term= '''[[Physics:Torque|Torque]]'''}}{{defn|defn=Twisting force.}}
{{term|term= '''[[Physics:Torsional vibration|Torsional vibration]]'''}}{{defn|defn=.}}
{{term|term= '''[[Physics:Toughness|Toughness]]'''}}{{defn|defn=.}}
{{term|term= '''[[Physics:Trajectory|Trajectory]]'''}}{{defn|defn=.}}
{{term|term= '''[[Engineering:Transducer|Transducer]]'''}}{{defn|defn=.}}
{{term|term= '''[[Engineering:Transformer|Transformer]]'''}}{{defn|defn=.}}
{{term|term= '''[[Trigonometric functions]]'''}}{{defn|defn=.}}
{{term|term= '''[[Trigonometry]]'''}}{{defn|defn=.}}
{{term|term= '''[[Trimean]]'''}}{{defn|defn=The '''trimean''' is a measure of a probability distribution's location defined as a weighted average of the distribution's median and its two quartiles}}
{{term|term= '''[[Chemistry:Triple point|Triple point]]'''}}{{defn|defn=.}}
{{term|term= '''[[Physics:Trouton's rule|Trouton's rule]]'''}}{{defn|defn=.}}
{{term|term= '''[[Truncated mean]]'''}}{{defn|defn=.}}
{{term|term= '''[[Physics:Truss|Truss]]'''}}{{defn|defn=.}}
{{term|term= '''[[Physics:Turbine|Turbine]]'''}}{{defn|defn=.}}
 {{term|term= '''[[Physics:Turbomachinery|Turbomachinery]]'''}}{{defn|defn=.}}
{{term|term= '''[[Physics:Turbulence|Turbulence]]'''}}{{defn|defn=.}}
{{glossary end}}

==U==

{{glossary}}

{{term|term= '''[[Physics:Ultimate tensile strength|Ultimate tensile strength]]'''}}{{defn|defn='''Ultimate tensile strength''' ('''UTS'''), often shortened to '''tensile strength''' ('''TS'''), '''ultimate strength''', or '''Ftu''' within equations,<ref name="stressebook.com" /><ref name="Degarmo 2003 31"/><ref name="Smith 2006 223"/> is the capacity of a material or structure to withstand loads tending to elongate, as opposed to [[Engineering:Compressive strength|compressive strength]], which withstands loads tending to reduce size. In other words, tensile strength resists [[Physics:Tension|tension]] (being pulled apart), whereas compressive strength resists [[Physics:Compression|compression]] (being pushed together). Ultimate tensile strength is measured by the maximum [[Physics:Stress (mechanics)|stress]] that a material can withstand while being stretched or pulled before breaking. In the study of [[Physics:Strength of materials|strength of materials]], tensile strength, compressive strength, and [[Engineering:Shear strength|shear strength]] can be analyzed independently.}}
{{term|term= '''[[Physics:Uncertainty principle|Uncertainty principle]]'''}}{{defn|defn=In [[Physics:Quantum mechanics|quantum mechanics]], the '''uncertainty principle''' (also known as '''Heisenberg's uncertainty principle''') is any of a variety of [[Inequality (mathematics)|mathematical inequalities]]<ref name=Sen2014>{{Cite journal |last1 = Sen | first1 = D. | title = The Uncertainty relations in quantum mechanics | url = http://www.currentscience.ac.in/Volumes/107/02/0203.pdf | journal = Current Science | volume = 107| issue = 2| year = 2014| pages = 203–218 }}</ref> asserting a fundamental limit to the precision with which certain pairs of physical properties of a [[Physics:Particle|particle]], known as [[Physics:Complementarity|complementary variables]], such as [[Position (vector)|position]] ''x'' and [[Physics:Momentum|momentum]] ''p'', can be known.}}
{{term|term= '''[[Unicode]]'''}}{{defn|defn=A standard for the consistent encoding of textual characters.}}
{{term|term= '''[[Unit vector]]'''}}{{defn|defn=In [[Mathematics|mathematics]], a '''unit vector''' in a [[Normed vector space|normed vector space]] is a [[Vector space|vector]] (often a spatial vector) of [[Norm (mathematics)|length]] 1. A unit vector is often denoted by a lowercase letter with a circumflex, or "hat": <math alt= i-hat>{\hat{\imath}}</math> (pronounced "i-hat"). The term direction vector is used to describe a unit vector being used to represent spatial direction, and such quantities are commonly denoted as '''d'''. .}}
{{term|term= '''Unsaturated compound'''}}{{defn|defn=.}}
{{term|term= '''Upthrust'''}}{{defn|defn=Buoyancy, or upthrust, is an upward [[Physics:Force|force]] exerted by a [[Physics:Fluid|fluid]] that opposes the [[Physics:Weight|weight]] of a partially or fully immersed object. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus the pressure at the bottom of a column of fluid is greater than at the top of the column. Similarly, the pressure at the bottom of an object submerged in a fluid is greater than at the top of the object. The pressure difference results in a net upward force on the object. The magnitude of the force is proportional to the pressure difference, and (as explained by [[Physics:Archimedes' principle|Archimedes' principle]]) is equivalent to the weight of the fluid that would otherwise occupy the submerged volume of the object, i.e. the [[Physics:Displacement (fluid)|displaced]] fluid.}}
{{term|term= '''[[Physics:Utility frequency|Utility frequency]]'''}}{{defn|defn=The utility frequency, (power) line frequency (American English) or mains frequency (British English) is the nominal [[Physics:Frequency|frequency]] of the oscillations of [[Physics:Alternating current|alternating current]] (AC) in a wide area synchronous grid transmitted from a [[Chemistry:Power station|power station]] to the end-user. In large parts of the world this is 50&nbsp;[[Hertz|Hz]], although in the [[Earth:Americas|Americas]] and parts of [[Earth:Asia|Asia]] it is typically 60&nbsp;Hz. Current usage by country or region is given in the list of [[Physics:Mains electricity by country|mains electricity by country]].}}
{{glossary end}}

==V==
{{glossary}}
{{term|term= '''[[Biology:Vacuole|Vacuole]]'''}}{{defn|defn= Is a [[Biology:Biological membrane|membrane]]-bound [[Biology:Organelle|organelle]] which is present in [[Biology:Plant cell|plant]] and [[Biology:Fungi|fungal]] [[Biology:Cell|cells]] and some [[Biology:Protist|protist]], [[Biology:Animal|animal]]<ref>{{cite book | last = Venes | first = Donald | name-list-style = vanc | date = 2001 | title = Taber's Cyclopedic Medical Dictionary | url = https://archive.org/details/taberscyclopedic19vene | url-access = registration | edition = Twentieth | publisher = F.A. Davis Company | location = Philadelphia | page = 2287 | isbn = 0-9762548-3-2 }}</ref> and [[Biology:Bacteria|bacteria]]l cells.<ref name=bacteria>{{cite book |volume =1|pages=295–298 |year=2006 | first = Heide N. | last = Schulz-Vogt | name-list-style = vanc |title=Inclusions in Prokaryotes |doi=10.1007/3-540-33774-1_10|series=Microbiology Monographs|isbn=978-3-540-26205-3|chapter=Vacuoles }}</ref> Vacuoles are essentially enclosed compartments which are filled with water containing inorganic and organic molecules including [[Biology:Enzymes|enzymes]] in solution, though in certain cases they may contain solids which have been engulfed. Vacuoles are formed by the fusion of multiple membrane vesicles and are effectively just larger forms of these.<ref>{{cite book | first1 = Robert J | last1 = Brooker | first2 = Eric P | last2 = Widmaier | first3 = Linda E | last3 = Graham | first4 = Peter D | last4 = Stiling | name-list-style = vanc | date = 2007 | title = Biology | edition = First | publisher = McGraw-Hill | location = New York | page = [https://archive.org/details/biology2008broo/page/79 79] | isbn = 978-0-07-326807-1 | url = https://archive.org/details/biology2008broo/page/79 }}</ref> The organelle has no basic shape or size; its structure varies according to the requirements of the cell.}}
{{term|term= '''[[Physics:Vacuum|Vacuum]]'''}}{{defn|defn= An absence of mass in a volume.}}
{{term|term= '''[[Chemistry:Valence|Valence]]'''}}{{defn|defn=In [[Chemistry:Chemistry|chemistry]], the '''valence''' or '''valency''' of an [[Chemistry:Chemical element|element]] is a measure of its combining power with other atoms when it forms [[Chemistry:Chemical compound|chemical compound]]s or [[Physics:Molecule|molecule]]s. The concept of  valence developed in the second half of the 19th century and helped successfully explain the molecular structure of inorganic and organic compounds.<ref name = "Partington">{{cite book |last=Partington |first=James Riddick |year=1921 |title=A text-book of inorganic chemistry for university students |url=https://archive.org/details/textbookofinorga00partuoft |edition=1st |ol=7221486M }}</ref> 
The quest for the underlying causes of valence led to the modern theories of chemical bonding, including the [[Physics:Cubical atom|cubical atom]] (1902), [[Chemistry:Lewis structure|Lewis structure]]s (1916), [[Chemistry:Valence bond theory|valence bond theory]] (1927), [[Chemistry:Molecular orbital|molecular orbital]]s (1928), [[Physics:VSEPR theory|valence shell electron pair repulsion theory]] (1958), and all of the advanced methods of [[Chemistry:Quantum chemistry|quantum chemistry]].}} 
{{term|term= '''Valence band'''}}{{defn|defn=In [[Physics:Solid-state physics|solid-state physics]], the valence band and conduction band are the [[Physics:Electronic band structure|bands]] closest to the [[Physics:Fermi level|Fermi level]] and thus determine the [[Physics:Electrical conductivity|electrical conductivity]] of the solid. In non-metals, the valence band is the highest range of [[Physics:Electron|electron]] [[Physics:Energy|energies]] in which electrons are normally present at [[Physics:Absolute zero|absolute zero]] temperature, while the conduction band is the lowest range of vacant electronic states. On a graph of the [[Physics:Electronic band structure|electronic band structure]] of a material, the valence band is located below the Fermi level, while the conduction band is located above it. The distinction between the valence and conduction bands is meaningless in metals, because conduction occurs in one or more partially filled bands that take on the properties of both the valence and conduction bands.}} 
{{term|term= '''[[Chemistry:Valence bond theory|Valence bond theory]]'''}}{{defn|defn=In [[Chemistry:Chemistry|chemistry]], valence bond (VB) theory is one of the two basic theories, along with [[Chemistry:Molecular orbital theory|molecular orbital (MO) theory]], that were developed to use the methods of [[Physics:Quantum mechanics|quantum mechanics]] to explain [[Chemistry:Chemical bond|chemical bond]]ing. It focuses on how the [[Physics:Atomic orbital|atomic orbital]]s of the dissociated atoms combine to give individual chemical bonds when a molecule is formed. In contrast, molecular orbital theory has orbitals that cover the whole molecule.<ref>{{cite book| last1 = Murrell| first1 = J. N.| last2 = Kettle| first2 = S. F. A.| last3 = Tedder| first3 = J. M.| title = The Chemical Bond| edition = 2nd| publisher = John Wiley & Sons| year = 1985| isbn = 0-471-90759-6| url-access = registration| url = https://archive.org/details/chemicalbond0000murr_e8r6}}</ref>}}
{{term|term= '''[[Physics:Valence electron|Valence electron]]'''}}{{defn|defn=In [[Chemistry:Chemistry|chemistry]] and [[Physics:Physics|physics]], a valence electron is an outer shell [[Physics:Electron|electron]] that is associated with an [[Physics:Atom|atom]], and that can participate in the formation of a [[Chemistry:Chemical bond|chemical bond]] if the outer shell is not closed; in a single [[Chemistry:Covalent bond|covalent bond]], both atoms in the bond contribute one valence electron in order to form a shared pair.}} 
{{term|term= '''Valence shell'''}}{{defn|defn=The valence shell is the set of [[Physics:Atomic orbital|orbital]]s which are energetically accessible for accepting electrons to form [[Chemistry:Chemical bond|chemical bond]]s. For main group elements, the valence shell consists of the ns and np orbitals in the outermost [[Physics:Electron shell|electron shell]]. In the case of [[Chemistry:Transition metal|transition metal]]s (the (n-1)d orbitals), and [[Chemistry:Lanthanide|lanthanide]]s and [[Chemistry:Actinide|actinide]]s (the (n-2)f and (n-1)d orbitals), the orbitals involved can also be in an inner electron shell. Thus, the ''shell'' terminology is a misnomer as there is no correspondence between the valence shell and any particular electron shell in a given element. A scientifically correct term would be ''valence orbital'' to refer to the energetically accessible orbitals of an element.}} 
{{term|term= '''[[Engineering:Valve|Valve]]'''}}{{defn|defn=Is a device or natural object that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways. Valves are technically fittings, but are usually discussed as a separate category. In an open valve, fluid flows in a direction from higher pressure to lower pressure. The word is derived from the Latin ''valva'', the moving part of a door, in turn from ''volvere'', to turn, roll.}}  
{{term|term= '''[[Physics:Van der Waals equation|van der Waals equation]]'''}}{{defn|defn=.}} 
{{term|term= '''[[Physics:Van der Waals force|van der Waals force]]'''}}{{defn|defn=In [[Physics:Molecular physics|molecular physics]], the Van der Waals force, named after Dutch physicist [[Biography:Johannes Diderik van der Waals|Johannes Diderik van der Waals]], is a distance-dependent interaction between atoms or molecules. Unlike ionic or covalent bonds, these attractions do not result from a chemical electronic bond; they are comparatively weak and therefore more susceptible to disturbance. The Van der Waals force quickly vanishes at longer distances between interacting molecules.}} 
{{term|term= '''[[Van 't Hoff equation|van 't Hoff equation]]'''}}{{defn|defn=.}} 
{{term|term= '''[[Van 't Hoff factor|van 't Hoff factor]]'''}}{{defn|defn=.}} 
{{term|term= '''[[Engineering:Variable capacitor|Variable capacitor]]'''}}{{defn|defn=.}} 
{{term|term= '''Variable resistor'''}}{{defn|defn=.}} 
{{term|term= '''[[Vector space]]'''}}{{defn|defn=.}} 
{{term|term= '''[[Physics:Venturi effect|Venturi effect]]'''}}{{defn|defn=.}} 
{{term|term= '''[[Vibration]]'''}}{{defn|defn=.}}
{{term|term= '''Virtual leak'''}}{{defn|defn=Traces of gas trapped in cavities within a vacuum chamber, slowly dissipating out in the main chamber, thus appearing like a leak from the outside.}} 
{{term|term= '''[[Physics:Viscoelasticity|Viscoelasticity]]'''}}{{defn|defn=.}} 
{{term|term= '''[[Physics:Viscosity|Viscosity]]'''}}{{defn|defn=The '''viscosity''' of a [[Physics:Fluid|fluid]] is the measure of its [[Physics:Drag|resistance]] to gradual deformation by [[Physics:Shear stress|shear stress]] or tensile stress.<ref>{{cite web|url=http://www.merriam-webster.com/dictionary/viscosity|title=viscosity|website=Merriam-Webster Dictionary}}</ref> For liquids, it corresponds to the informal concept of "thickness": for example, [[Chemistry:Honey|honey]] has a higher viscosity than [[Chemistry:Water|water]].<ref>{{cite book| last = Symon| first = Keith| title = Mechanics| edition = 3rd| publisher = Addison-Wesley| date = 1971| isbn = 978-0-201-07392-8}}</ref>}} 
{{term|term= '''[[Volt-ampere]]'''}}{{defn|defn=(VA), is the unit used for the apparent power in an [[Physics:Electrical circuit|electrical circuit]]. The apparent power equals the product of root-mean-square (RMS) [[Physics:Voltage|voltage]] and RMS current.<ref>Ciletti, M. D., Irwin, J. D., Kraus, A. D., Balabanian, N., Bickard, T. A., and Chan, S. P. (1993). Linear circuit analysis. In ''Electrical Engineering Handbook,'' edited by R. C. Dorf. Boca Raton: CRC Press. (pp.82–87)</ref> In [[Physics:Direct current|direct current]] (DC) circuits, this product is equal to the real power (active power)<ref>''IEEE 100 : the authoritative dictionary of IEEE standards terms.-7th ed.'' {{ISBN|0-7381-2601-2}}, page 23</ref> in [[Watt|watt]]s. Volt-amperes are useful only in the context of [[Physics:Alternating current|alternating current]] (AC) circuits. The volt-ampere is dimensionally equivalent to the [[Watt|watt]] (in SI units, 1 VA = 1 N m A<sup>−1</sup> s <sup>−1</sup> A = 1 N m s <sup>−1</sup> = 1 J s <sup>−1</sup> = 1 W). VA rating is most useful in rating wires and switches (and other power handling equipment) for inductive loads.}} 
{{term|term= '''[[Volt-ampere reactive]]'''}}{{defn|defn=.}} 
{{term|term= '''[[Chemistry:Volta potential|Volta potential]]'''}}{{defn|defn=The '''Volta potential''' (also called '''Volta potential difference''', '''contact potential difference''', '''outer potential difference''', Δψ, or "delta psi") in [[Chemistry:Electrochemistry|electrochemistry]], is the electrostatic potential difference between two metals (or one metal and one [[Physics:Electrolyte|electrolyte]]) that are in contact and are in thermodynamic equilibrium. Specifically, it is the potential difference between a point close to the surface of the first metal,  and a point close to the surface of the second metal (or [[Physics:Electrolyte|electrolyte]]).<ref>[http://goldbook.iupac.org/C01293.html IUPAC Gold Book, definition of contact (Volta) potential difference.]</ref>}} 
{{term|term= '''[[Physics:Voltage|Voltage]]'''}}{{defn|defn='''Voltage''', '''electric potential difference''', '''electric pressure ''' or '''electric tension''' is the difference in [[Physics:Electric potential|electric potential]] between two points. The difference in electric potential between two points (i.e., voltage) is defined as the [[Physics:Work (electrical)|work]] needed per [[Physics:Test charge|unit of charge]] against a static [[Physics:Electric field|electric field]] to move a [[Physics:Test charge|test charge]] between the two points. In the International System of Units, the [[SI derived unit|derived unit]] for voltage is named ''[[Volt|volt]]''.<ref name="volt">{{SIbrochure8th}}, p. 144</ref> In SI units,  work per unit charge is expressed as joules per coulomb, where 1 volt = 1 [[Joule|joule]] (of work) per 1 [[Coulomb|coulomb]] (of charge). The official SI definition for ''volt'' uses power and current, where 1 volt = 1 [[Watt|watt]] (of power) per 1 [[Ampere|ampere]] (of current).<ref name="volt"/>}} 
{{term|term= '''[[Physics:Volumetric flow rate|Volumetric flow rate]]'''}}{{defn|defn=Also known as '''volume flow rate''', '''rate of fluid flow''' or '''volume velocity''', is the volume of fluid which passes per unit time; usually represented by the symbol {{mvar|Q}} (sometimes {{mvar|V̇}}). The SI unit is m<sup>3</sup>/s ([[Cubic metre per second|cubic metres per second]]).}} 
{{term|term= '''[[Von Mises yield criterion|von Mises yield criterion]]'''}}{{defn|defn=The '''von Mises yield criterion''' (also known as the maximum distortion energy criterion<ref>{{cite news|title=Von Mises Criterion (Maximum Distortion Energy Criterion)|url=https://www.engineersedge.com/material_science/von_mises.htm|access-date=8 February 2018|publisher=Engineer's edge}}</ref>) suggests that [[Engineering:Yield (engineering)|yielding]] of a ductile material begins when the [[Physics:Cauchy stress tensor#Stress deviator tensor|second deviatoric stress invariant]] <math>J_2</math> reaches a critical value.<ref name="von Mises, R. 1913">von Mises, R. (1913). ''Mechanik der festen Körper im plastisch deformablen Zustand.'' Göttin. Nachr. Math. Phys., vol. 1, pp. 582–592.</ref> It is part of plasticity theory that applies best to ductile materials, such as some metals. Prior to yield, material response can be assumed to be of a nonlinear elastic, viscoelastic, or linear elastic behavior.

In [[Physics:Materials science|materials science]] and [[Engineering:Engineering|engineering]] the von Mises yield criterion can also be formulated in terms of the '''von Mises stress''' or '''equivalent tensile stress''', <math>\sigma_v</math>. This is a scalar value of stress that can be computed from the [[Physics:Cauchy stress tensor|Cauchy stress tensor]]. In this case, a material is said to start yielding when the von Mises stress reaches a value known as yield strength, <math>\sigma_y</math>. The von Mises stress is used to predict yielding of materials under complex loading from the results of uniaxial tensile tests. The von Mises stress satisfies the property where two stress states with equal distortion energy have an equal von Mises stress.}} 
{{glossary end}}

==W==
{{glossary}}

{{term|term= '''[[Watt]]'''}}{{defn|defn=The SI unit of power, rate of doing work.}}  
{{term|term= '''[[Wave]]'''}}{{defn|defn=Is a disturbance that transfers [[Physics:Energy|energy]] through [[Physics:Matter|matter]] or space, with little or no associated [[Physics:Mass|mass]] transport. Waves consist of [[Oscillation|oscillation]]s or [[Vibration|vibration]]s of a physical [[Physics:Transmission medium|medium]] or a [[Physics:Field|field]], around relatively fixed locations. From the perspective of mathematics, waves, as functions of time and space, are a class of [[Signal|signal]]s.<ref>Pragnan Chakravorty, "What Is a Signal? [Lecture Notes],"&nbsp;IEEE Signal Processing Magazine, vol. 35, no. 5, pp. 175-177, Sept. 2018.&nbsp;https://doi.org/10.1109/MSP.2018.2832195</ref>}} 
{{term|term= '''[[Wavelength]]'''}}{{defn|defn=Is the '''spatial period''' of a periodic wave—the distance over which the wave's shape repeats.<ref name=hecht>
{{cite book
 |first=Eugene
 |last=Hecht
 |year=1987
 |title=Optics
 |edition=2nd
 |publisher=Addison Wesley
 |isbn=978-0-201-11609-0
 |pages=15–16
 }}</ref><ref name=Flowers>
{{cite book
 |title=An introduction to numerical methods in C++
 |chapter=§21.2 Periodic functions
 |page=473
 |chapter-url=https://books.google.com/books?id=weYj75E_t6MC&pg=RA1-PA473
 |author=Brian Hilton Flowers
 |isbn=978-0-19-850693-5
 |year=2000
 |edition=2nd
 |publisher = Cambridge University Press
 }}</ref> 
It is thus the [[Multiplicative inverse|inverse]] of the [[Spatial frequency|spatial frequency]]. Wavelength is usually determined by considering the distance between consecutive corresponding points of the same [[Physics:Phase (waves)|phase]], such as crests, troughs, or [[Zero crossing|zero crossing]]s and is a characteristic of both traveling waves and [[Physics:Standing wave|standing wave]]s, as well as other spatial wave patterns.<ref name=Seaway>
{{cite book
 |title=Principles of physics
 |author1=Raymond A. Serway |author2=John W. Jewett |pages=404, 440
 |url=https://books.google.com/books?id=1DZz341Pp50C&pg=PA404
 |edition=4th
 |isbn=978-0-534-49143-7
 |publisher=Cengage Learning
 |year=2006 }}</ref><ref>
{{cite book
 | title=The surface physics of liquid crystals
 | author=A. A. Sonin
 | publisher=Taylor & Francis
 | year=1995
 | isbn=978-2-88124-995-2
 | page=17
}}</ref> 
Wavelength is commonly designated by the Greek letter ''lambda'' (λ). 
The term ''wavelength'' is also sometimes applied to [[Engineering:Modulation|modulated]] waves, and to the sinusoidal [[Envelope (mathematics)|envelopes]] of modulated waves or waves formed by interference of several sinusoids.<ref>
{{cite book
 | title = Electromagnetic Theory for Microwaves and Optoelectronics
 |author1=Keqian Zhang |author2=Dejie Li
 |name-list-style=amp | publisher = Springer 
 | year = 2007
 | isbn = 978-3-540-74295-1
 | page = 533
 | url = https://books.google.com/books?id=3Da7MvRZTlAC&q=wavelength+modulated-wave+envelope&pg=PA533
 }}</ref>' .}} 
{{term|term= '''Wedge'''}}{{defn|defn=Is a [[Triangle|triangular]] shaped tool, and is a portable [[Engineering:Inclined plane|inclined plane]], and one of the six classical [[Engineering:Simple machine|simple machine]]s. It can be used to separate two objects or portions of an object, lift up an object, or hold an object in place. It functions by converting a [[Physics:Force|force]] applied to its blunt end into forces perpendicular (normal) to its inclined surfaces. <!-- this link is broken <ref>{{Citation | title = Wedges and screws | url = http://em-ntserver.unl.edu/Negahban/em223/note16/note16.htm | access-date = 2009-07-29}}.</ref> --> The [[Physics:Mechanical advantage|mechanical advantage]] of a wedge is given by the ratio of the length of its slope to its width.<ref name="bowser">{{Citation | last = Bowser | first = Edward Albert | title = An elementary treatise on analytic mechanics: with numerous examples | publisher = D. Van Nostrand Company | pages= 202–203 | year = 1920 | edition = 25th | url = https://books.google.com/books?id=mE4GAQAAIAAJ}}.</ref><ref name="CEST">''McGraw-Hill Concise Encyclopedia of Science & Technology'', Third Ed., Sybil P. Parker, ed., McGraw-Hill, Inc., 1992, p. 2041.</ref> Although a short wedge with a wide angle may do a job faster, it requires more force than a long wedge with a narrow angle.}} 
{{term|term= '''[[Weighted arithmetic mean]]'''}}{{defn|defn=The '''weighted arithmetic mean''' is similar to an ordinary [[Arithmetic mean|arithmetic mean]] (the most common type of [[Average|average]]), except that instead of each of the data points contributing equally to the final average, some data points contribute more than others. The notion of weighted mean plays a role in [[Descriptive statistics|descriptive statistics]] and also occurs in a more general form in several other areas of mathematics. If all the weights are equal, then the weighted mean is the same as the [[Arithmetic mean|arithmetic mean]]. While weighted means generally behave in a similar fashion to arithmetic means, they do have a few counterintuitive properties, as captured for instance in [[Simpson's paradox]].}} 
{{term|term= '''[[Physics:Wet-bulb temperature|Wet-bulb temperature]]'''}}{{defn|defn=The temperature of a wetted thermometer with an air current across it. Used in psychrometry. .}} 
{{term|term= '''[[Engineering:Wheel and axle|Wheel and axle]]'''}}{{defn|defn=Are one of six [[Engineering:Simple machine|simple machine]]s identified by Renaissance scientists drawing from Greek texts on technology.<ref>Wheel and Axle, The World Book Encyclopedia, World Book Inc., 1998, pp. 280-281</ref> The wheel and axle consists of a wheel attached to a smaller [[Engineering:Axle|axle]] so that these two parts rotate together in which a force is transferred from one to the other. A [[Engineering:Hinge|hinge]] or [[Physics:Bearing (mechanical)|bearing]] supports the axle, allowing rotation. It can amplify force; a small force applied to the periphery of the large wheel can move a larger load attached to the axle.}} 
{{term|term= '''[[Winsorized mean]]'''}}{{defn|defn=Is a winsorized statistical measure of central tendency, much like the [[Mean|mean]] and [[Median|median]], and even more similar to the [[Truncated mean|truncated mean]]. It involves the calculation of the mean after replacing given parts of a [[Probability distribution|probability distribution]] or [[Sampling (statistics)|sample]] at the high and low end with the most extreme remaining values,<ref>Dodge, Y (2003) ''The Oxford Dictionary of Statistical Terms'', OUP. {{ISBN|0-19-920613-9}} (entry for "winsorized estimation")</ref> typically doing so for an equal amount of both extremes; often 10 to 25 percent of the ends are replaced. The winsorized mean can equivalently be expressed as a weighted average of the truncated mean and the quantiles at which it is limited, which corresponds to replacing parts with the corresponding quantiles.}} 
{{term|term= '''[[Engineering:Work hardening|Work hardening]]'''}}{{defn|defn=Also known as '''strain hardening''', is the [[Physics:Strength of materials|strengthening]] of a metal or polymer by plastic deformation. This strengthening occurs because of dislocation movements and dislocation generation within the [[Chemistry:Crystal structure|crystal structure]] of the material.<ref>{{harvnb|Degarmo|Black|Kohser|2003|p=60}}.</ref>}} 
{{glossary end}}

==X==
{{glossary}}
{{term|term= '''[[Cartesian coordinate system|X-axis]]'''}}{{defn|defn=In algebraic geometry, the axis on a [[Graph of a function|graph]] that is usually drawn left to right and usually shows the range of values of an independent variable.<ref>[https://en.wiktionary.org/wiki/x-axis Wiktionary]</ref>}}
{{glossary end}}

==Y==
{{glossary}}

{{term|term= '''[[Cartesian coordinate system|Y-axis]]'''}}{{defn|defn=In algebraic geometry, the axis on a [[Graph of a function|graph]] that is usually drawn from bottom to top and usually shows the range of values of [[Variable (mathematics)|variable]] dependent on one other variable, or the second of two independent variables.<ref>[https://en.wiktionary.org/wiki/y-axis Wiktionary]</ref>
}} 
{{term|term= '''[[Engineering:Yield (engineering)|Yield]]'''}}{{defn|defn=The point of maximum elastic deformation of a material; above yield the material is permanently deformed.}} 
{{term|term= '''[[Physics:Young's modulus|Young's modulus]]'''}}{{defn|defn=A measure of the stiffness of a material; the amount of force per unit area require to produce a unit strain.}} 
{{glossary end}}

==Z==
{{glossary}}

{{term|term= '''[[Cartesian coordinate system|Z-axis]]'''}}{{defn|defn=In algebraic geometry, the axis on a [[Graph of a function|graph]] of at least three [[Physics:Dimension|dimension]]s that is usually drawn vertically and usually shows the range of values of a [[Variable (mathematics)|variable]] dependent on two other variables or the third independent variable.<ref>[https://en.wiktionary.org/wiki/z-axis Wiktionary]</ref>}}

{{term|term= '''Zero defects'''}}{{defn|defn=A quality assurance philosophy that aims to reduce the need for inspection of components by improving their quality.}}
{{term|term= '''[[Zero force member]]'''}}{{defn|defn=In the field of [[Engineering:Engineering mechanics|engineering mechanics]], a '''zero force member''' is a member (a single truss segment) in a [[Physics:Truss|truss]] which, given a specific [[Structural load|load]], is at rest: neither in tension, nor in compression. In a truss a zero force member is often found at pins (any connections within the truss) where no external load is applied and three or fewer truss members meet. Recognizing basic zero force members can be accomplished by analyzing the [[Physics:Force|force]]s acting on an individual pin in a physical [[Philosophy:System|system]].

''NOTE: If the pin has an external force or [[Physics:Moment|moment]] applied to it, then all of the members attached to that pin are not zero force members UNLESS the external force acts in a manner that fulfills one of the rules below:''

* If two non-collinear members meet in an unloaded [[Engineering:Joint (building)|joint]], both are zero-force members.
* If three members meet in an unloaded joint of which two are collinear, then the third member is a zero-force member.

'''Reasons for Zero-force members in a truss system'''
*These members contribute to the stability of the structure, by providing buckling prevention for long slender members under compressive forces
*These members can carry loads in the event that variations are introduced in the normal external loading configuration.}}
{{term|term= '''[[Physics:Zeroth law of thermodynamics|Zeroth law of thermodynamics]]'''}}{{defn|defn=The equivalence principle applied to temperature; two systems in thermal equiplbirum with a third are also in thermal equilibrium with each other. }}
{{glossary end}}


== See also ==
{{colbegin}}
*[[Engineering:Engineering|Engineering]]
*National Council of Examiners for Engineering and Surveying
*Fundamentals of Engineering Examination
*Principles and Practice of Engineering Examination
*Graduate Aptitude Test in Engineering
*[[Engineering:Glossary of aerospace engineering|Glossary of aerospace engineering]]
*[[Engineering:Glossary of civil engineering|Glossary of civil engineering]]
*[[Engineering:Glossary of electrical and electronics engineering|Glossary of electrical and electronics engineering]]
*[[Engineering:Glossary of mechanical engineering|Glossary of mechanical engineering]]
*[[Engineering:Glossary of structural engineering|Glossary of structural engineering]]
*[[Engineering:Glossary of architecture|Glossary of architecture]]
*[[Glossary of areas of mathematics]]
*[[Glossary of artificial intelligence]]
*[[Astronomy:Glossary of astronomy|Glossary of astronomy]]
*Glossary of biology
*[[Glossary of calculus]]
*[[Chemistry:Glossary of chemistry terms|Glossary of chemistry]]
*[[Earth:Glossary of ecology|Glossary of ecology]]
*Glossary of economics
*Glossary of physics
*[[Glossary of probability and statistics]]
*{{slink|List of established military terms|Engineering}}
{{colend}}

==Notes==
{{reflist|group=note}}
{{reflist|group=lower-alpha}}
{{notelist}}
{{reflist|group=lower-alpha}}
{{notelist}}
{{reflist|group=Note}}

== References ==
{{Reflist}}
{{reflist|group=p}}

{{Engineering fields}}
{{Glossaries of science and engineering}}

[[Category:Engineering disciplines]]

{{Sourceattribution|Glossary of engineering|1}}