View source for Glossary of engineering: A–L

{{short description|List of definitions of terms and concepts commonly used in the study of engineering}}
{{See also|Glossary of engineering: M–Z}}

This '''glossary of engineering terms''' is a list of definitions about the major concepts of [[engineering]]. Please see the bottom of the page for glossaries of specific fields of engineering.

{{Compact TOC|side=yes|center=yes|nobreak=yes|seealso=yes|refs=yes|num=|extlinks=yes|m=[[#M-Z|M-Z]]|n=|o=|p=|q=|r=|s=|t=|u=|v=|w=|x=|y=|z=}}

{{TopicTOC-Engineering}}

== A ==
{{glossary}}
{{term|term= '''[[Absolute electrode potential]]'''}}{{defn|defn=In [[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 [[electrode potential]] of a [[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]], so it is equal to gauge pressure plus atmospheric pressure.}} 
{{term|term= '''[[Absolute zero]]'''}}{{defn|defn=The lower limit of the [[thermodynamic temperature]] scale, a state at which the [[enthalpy]] and [[entropy]] of a cooled [[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, [[zero-point energy]]-induced particle motion. The theoretical temperature is determined by extrapolating the [[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-date=1967 |access-date=20 June 2017  |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|archive-date=2013-04-01|archive-url=https://web.archive.org/web/20130401180715/http://www.smithsonianmag.com/science-nature/absolute-zero-200801.html}}</ref> The corresponding [[Kelvin]] and [[Rankine scale|Rankine]] temperature scales set their zero points at absolute zero by definition.
}}
{{term|term= '''[[Absorbance]]'''}}{{defn|defn=Absorbance or ''decadic absorbance'' is the ''[[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'' [[Radiant power|spectral radiant power]] through a material.<ref name=GoldBook>{{GoldBookRef|title=Absorbance|file=A00028|accessdate=2015-03-15}}</ref>}} 
{{term|term= '''[[AC power]]'''}}{{defn|defn= Electric power delivered by alternating current; common household power is AC.}}
{{term|term= '''[[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= '''[[Acid]]'''}}{{defn|defn=A [[molecule]] or [[ion]] capable of donating a [[Hydron (chemistry)|hydron]] (proton or hydrogen ion H<sup>+</sup>), or, alternatively, capable of forming a [[covalent bond]] with an [[electron pair]] (a Lewis acid).<ref name="IUPAC_acid">[http://goldbook.iupac.org/A00071.html IUPAC Gold Book – acid]</ref>}} 
{{term|term= '''[[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= '''[[Acid strength]]'''}}{{defn|defn=In strong acids, most of the molecules give up a hydrogen ion and become ionized.}}
{{term|term= '''[[Acoustics]]'''}}{{defn|defn=The scientific study of sound.}} 
{{term|term= '''[[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= '''[[Activated sludge model]]'''}}{{defn|defn=A generic name for a group of mathematical methods to model activated sludge systems.}} 
{{term|term= '''[[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 [[adenosine triphosphate|ATP]], and ''secondary active transport'' that uses an electrochemical gradient. An example of active transport in [[human physiology]] is the uptake of [[glucose]] in the [[gastrointestinal tract|intestines]].}} 
{{term|term= '''[[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= '''[[Adenosine triphosphate]]'''}}{{defn|defn=A complex [[organic compound|organic chemical]] that provides energy to drive many processes in living [[cell (biology)|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 [[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= '''[[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= '''[[Adiabatic process]]'''}}{{defn|defn=A process where no heat energy is lost to outside space.}}  
{{term|term= '''[[Adiabatic wall]]'''}}{{defn|defn= A barrier through which heat energy cannot pass.}} 
{{term|term= '''[[Aerobic digestion]]'''}}{{defn|defn=A process in [[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|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= '''[[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= '''[[Aerospace engineering]]'''}}{{defn|defn=Is the primary field of [[engineering]] concerned with the development of [[aircraft]] and [[spacecraft]].<ref>''Encyclopedia of Aerospace Engineering''. [[John Wiley & Sons]], 2010. {{ISBN|978-0-470-75440-5}}.</ref> It has two major and overlapping branches: Aeronautical engineering and Astronautical Engineering. [[Avionics]] engineering is similar, but deals with the [[electronic engineering|electronics]] side of aerospace engineering.

 }}
{{term|term= '''[[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&dq=afocal&pg=PA379 Daniel Malacara, Zacarias Malacara, Handbook of optical design. Page 379]</ref>}}
{{term|term= '''[[Agricultural engineering]]'''}}{{defn|defn=The profession of designing machinery, processes, and systems for use in agriculture.}}
{{term|term= '''[[Albedo]]'''}}{{defn|defn=A measure of the fraction of light reflected from an astronomical body or other object.}}
{{term|term= '''[[Alkane]]'''}}{{defn|defn=An alkane, or ''paraffin'' (a historical name that also has [[paraffin (disambiguation)|other meanings]]), is an [[open-chain compound|acyclic]] [[Saturated and unsaturated compounds|saturated]] [[hydrocarbon]]. In other words, an alkane consists of [[hydrogen]] and [[carbon]] atoms arranged in a [[tree (graph theory)|tree]] structure in which all the [[carbon–carbon bond]]s are [[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= '''[[Alkene]]'''}}{{defn|defn=An [[unsaturated hydrocarbon]] that contains at least one [[carbon]]–carbon [[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= '''[[Alkyne]]'''}}{{defn|defn=Is an [[Saturated and unsaturated compounds|unsaturated]] [[hydrocarbon]] containing at least one carbon—carbon [[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 [[functional group]]s form a [[homologous series]] with the general chemical formula {{chem2|[[carbon|C]]_{''n''}[[Hydrogen|H]]_{2''n''−2} }}. }}
{{term|term= '''[[Alloy]]'''}}{{defn|defn=is a combination of [[metal]]s or of a metal and another [[Chemical element|element]]. Alloys are defined by a [[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= '''[[Alpha particle]]'''}}{{defn|defn=Alpha particles consist of two [[proton]]s and two [[neutron]]s bound together into a particle identical to a [[helium-4]] [[atomic nucleus|nucleus]]. They are generally produced in the process of [[alpha decay]], but may also be produced in other ways. Alpha particles are named after the first letter in the [[Greek alphabet]], [[Alpha|α]].}} 
{{term|term= '''[[Alternating current]]'''}}{{defn|defn=Electrical current that regularly reverses direction.}} 
{{term|term= '''[[Alternative hypothesis]]'''}}{{defn|defn=In [[statistical hypothesis testing]],
the alternative hypothesis (or ''maintained hypothesis'' or ''research hypothesis'') and the [[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]] and [[predictive power]].}}
{{term|term= '''[[Ammeter]]'''}}{{defn|defn=An instrument that measures current.}}
{{term|term= '''[[Amino acids]]'''}}{{defn|defn=Are [[organic compound]]s containing [[amine]] (–NH<sub>2</sub>) and [[Carboxylic acid|carboxyl]] (–COOH) [[functional group]]s, along with a [[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 [[Chemical element|elements]] of an amino acid are [[carbon]] (C), [[hydrogen]] (H), [[oxygen]] (O), and [[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 [[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= '''[[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 {{gli|coulomb}} per second.}} 
{{term|term= '''[[Amphoterism]]'''}}{{defn|defn=In chemistry, an '''amphoteric''' compound is a molecule or ion that can react both as an [[acid]] as well as a [[base (chemistry)|base]].<ref>{{GoldBookRef | title = amphoteric | file = A00306}}</ref> Many metals (such as [[copper]], [[zinc]], [[tin]], [[lead]], [[aluminium]], and [[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= '''[[Amplifier]]'''}}{{defn|defn=A device that replicates a signal with increased power.}}
{{term|term= '''[[Amplitude]]'''}}{{defn|defn=The amplitude of a [[Periodic function|period]]ic [[Variable (mathematics)|variable]] is a measure of its change over a single [[Period (mathematics)|period]] (such as [[period (physics)|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 [[Phase (waves)|phase]] is sometimes called the amplitude.<ref>{{Cite book | author1=Knopp, Konrad| author2= Bagemihl, Frederick | author-link1=Konrad Knopp | title=Theory of Functions Parts I and II | year=1996 | publisher=Dover Publications | isbn=978-0-486-69219-7 | page=3}}</ref>}}
{{term|term= '''[[Anaerobic digestion]]'''}}{{defn|defn= Is a collection of processes by which [[microorganisms]] break down [[biodegradable]] material in the absence of [[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 [[Waste management|manage waste]] or to produce fuels. Much of the [[Fermentation (biochemistry)|fermentation]] used industrially to produce food and drink products, as well as home fermentation, uses anaerobic digestion.}}
{{term|term= '''[[Angular acceleration]]'''}}{{defn|defn=Is the  rate of change of [[angular velocity]]. In three dimensions, it is a [[pseudovector]]. In [[SI]] units, it is measured in [[radians]] per [[second]] squared (rad/s{{sup|2}}), and is usually denoted by the Greek letter [[alpha (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  }}</ref>}}
{{term|term= '''[[Angular momentum]]'''}}{{defn|defn=In [[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 [[torque]].}}
{{term|term= '''[[Angular velocity]]'''}}{{defn|defn=In [[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 [[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 | author-link =University of Colorado Boulder | access-date =November 4, 2018 | archive-date =May 13, 2021 | archive-url =https://web.archive.org/web/20210513000709/http://ruby.colorado.edu/~smyth/G101-2.html  }}</ref>}}
{{term|term= '''[[Annealing (metallurgy)]]'''}}{{defn|defn=A heat treatment process that relieves internal stresses.}}
{{term|term= '''[[Annihilation]]'''}}{{defn|defn=In [[particle physics]], annihilation is the process that occurs when a [[subatomic particle]] collides with its respective [[antiparticle]] to produce other particles, such as an [[electron]] colliding with a [[positron]] to produce two [[photon]]s.<ref>
{{cite web
 |title=Antimatter
 |url=http://www.lbl.gov/abc/Antimatter.html
 |publisher=[[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 [[energy]] and [[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 [[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 [[conservation of energy]] and [[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=[[Lawrence Berkeley National Laboratory]]
 |access-date=17 October 2011
}}</ref>}}
{{term|term= '''[[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 [[Standardization|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= '''[[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 [[gravity]]. It does not refer to the lack of weight under gravity experienced in [[free fall]] or [[orbit]], or to balancing the force of gravity with some other force, such as electromagnetism or aerodynamic lift.}}
{{term|term= '''[[Applied engineering (field)|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 design]]s, 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]], 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  }}</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=Arc length is the distance between two points along a section of a [[curve]].  Determining the length of an irregular arc segment is also called {{em|rectification}} of a curve. The advent of [[infinitesimal calculus]] led to a general formula that provides [[closed-form expression|closed-form solutions]] in some cases.}}
{{term|term= '''[[Archimedes' principle]]'''}}{{defn|defn=States that the upward [[buoyancy|buoyant force]] that is exerted on a body immersed in a [[fluid]], whether fully or partially submerged, is equal to the [[weight]] of the fluid that the body [[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 [[Archimedes|Archimedes of Syracuse]]<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=2009-06-13 |archive-url=https://web.archive.org/web/20110727224657/http://archive.rubicon-foundation.org/5990 |archive-date=2011-07-27 |url-status=usurped }}</ref>}}
{{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]] over the object in question. Its dimension is L (length) to the fourth power. Its [[physical unit|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]] and [[statistics]], the '''arithmetic mean'''  or simply the [[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]], an '''arithmetic progression ''' (AP) or '''arithmetic sequence''' is a [[sequence]] of [[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= '''[[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 [[hydrocarbon]] with [[sigma bond]]s and delocalized [[pi electron]]s between carbon atoms forming a circle. In contrast, [[Aliphatic compound|aliphatic]] hydrocarbons lack this delocalization. The term "aromatic" was assigned before the physical mechanism determining [[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, [[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 [[reaction rate]]s. The equation was proposed by [[Svante Arrhenius]] in 1889, based on the work of Dutch chemist [[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 [[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">[[Keith J. Laidler|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 [[intelligence]] demonstrated by [[machine]]s, unlike the natural intelligence<!--boldface per WP:R#PLA--> [[human intelligence|displayed by humans]] and [[animal cognition|animals]]. Leading AI textbooks define the field as the study of "[[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= '''[[Atomic orbital]]'''}}{{defn|defn=In [[atomic theory]] and [[quantum mechanics]], an atomic orbital is a [[Function (mathematics)|mathematical function]] that describes the wave-like behavior of either one [[electron]] or a pair of electrons in an [[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]] of finding any electron of an atom in any specific region around the [[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= '''[[Atomic packing factor]]'''}}{{defn|defn=The percentage of the volume filled with atomic mass in a crystal formation.}}  
{{term|term= '''[[Audio frequency]]'''}}{{defn|defn=An audio frequency (abbreviation: AF), or '''audible frequency''' is characterized as a [[periodic function|periodic]] [[vibration]] whose [[frequency]] is audible to the average human. The [[International System of Units|SI unit]] of audio frequency is the [[hertz]] (Hz). It is the property of [[sound]] that most determines [[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=978-0-470-16794-6 }}</ref>}} 
{{term|term= '''[[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 [[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...40.1355L |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= '''[[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]]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= '''[[Azimuthal quantum number]]'''}}{{defn|defn=The '''azimuthal quantum number''' is a [[quantum number]] for an [[atomic orbital]] that determines its [[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 [[quantum state]] of an electron (the others being the [[principal quantum number]], following [[spectroscopic notation]], the [[magnetic quantum number]], and the [[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}}

{{Glossary of engineering ToC}}

==B==
{{glossary}}

{{term|term= '''[[Barometer]]'''}}{{defn|defn= A device for measuring pressure.}}
{{term|term= '''[[Battery (electricity)|Battery]]'''}}{{defn|defn=Electrochemical cells that transform chemical energy into electricity.}} 
{{term|term= '''[[Base (chemistry)|Base]]'''}}{{defn|defn=In [[chemistry]],  '''bases''' are substances that, in [[aqueous solution]], release [[hydroxide]] (OH<sup>−</sup>) ions, are slippery to the touch, can taste [[Taste#Bitterness|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=978-1-4292-0989-2|edition=2nd|location=New York |oclc=392223218}}</ref> change the color of indicators (e.g., turn red [[litmus paper]] blue), react with [[acid]]s to form [[salts]], promote certain chemical reactions ([[base catalysis]]), accept [[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= '''[[Beam (structure)|Beam]]'''}}{{defn|defn=A structural element whose length is significantly greater than its width or height.}}
{{term|term= '''[[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 [[Absorption (electromagnetic radiation)|attenuation]] of [[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 [[physical optics]], for [[photons]], [[neutrons]] or rarefied gases. In [[mathematical physics]], this law arises as a solution of the [[Bhatnagar–Gross–Krook|BGK equation]].}}
{{term|term= '''[[Belt (mechanical)|Belt]]'''}}{{defn|defn=A closed loop of flexible material used to transmit mechanical power from one pulley to another.}}
{{term|term= '''[[Belt friction]]'''}}{{defn|defn=Is a term describing the friction forces between a [[Belt (mechanical)|belt]] and a surface, such as a belt wrapped around a [[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 [[tension (physics)|tension]] in the belt can be different at both ends of the belt. Belt friction can be modeled by the [[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= '''[[Bending]]'''}}{{defn|defn=In [[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= '''[[Bending moment]]'''}}{{defn|defn=In [[solid mechanics]], a bending moment is the [[Reaction (physics)|reaction]] induced in a [[structural element]] when an external [[force]] or [[Moment of force|moment]] is applied to the element, causing the element to [[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=0-534-93429-3|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 [[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]], an [[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 [[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 [[fluid dynamics]], '''Bernoulli's principle''' states that an increase in the speed of a fluid occurs simultaneously with a decrease in [[pressure]] or a decrease in the [[fluid]]'s [[potential energy]].<ref name="Clancy1975">{{cite book|last=Clancy|first=L. J. |author-link=Laurence Joseph Clancy|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 [[Daniel Bernoulli]] who published it in his book ''[[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 [[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=978-1-4398-4957-6|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 flow]]s: when the effects of [[irreversible process]]es (like [[turbulence]]) and non-[[adiabatic process]]es (e.g. [[heat radiation]]) are small and can be neglected.}}
{{term|term= '''[[Beta particle]]'''}}{{defn|defn=also called '''beta ray''' or '''beta radiation''' (symbol '''β'''), is a high-energy, high-speed [[electron]] or [[positron]] emitted by the [[radioactive decay]] of an [[atomic nucleus]] during the process of [[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
|archive-date=24 March 2020
|archive-url=https://web.archive.org/web/20200324112546/https://www2.lbl.gov/abc/wallchart/chapters/03/2.html

}}</ref>}}
{{term|term= '''[[Binomial distribution]]'''}}{{defn|defn=In [[probability theory]] and [[statistics]], the '''binomial distribution''' with parameters ''n'' and ''p'' is the [[discrete probability distribution]] of the number of successes in a sequence of ''n'' [[statistical independence|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]] containing a single [[bit]] of information: [[wikt:success|success]]/[[yes and no|yes]]/[[truth|true]]/[[one]] (with [[probability]] ''p'') or [[failure]]/no/[[false (logic)|false]]/[[zero]] (with [[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]] of [[statistical significance]].}}
{{term|term= '''[[Biocatalysis]]'''}}{{defn|defn='''Biocatalysis''' refers to the use of [[life|living]] (biological) systems or their parts to speed up ([[catalysis|catalyze]]) chemical reactions. In biocatalytic processes, natural catalysts, such as [[enzyme]]s, perform chemical transformations on [[organic compounds]]. Both enzymes that have been more or less [[list of purification methods in chemistry|isolated]] and enzymes still residing inside living [[cell (biology)|cells]] are employed for this task.<ref>{{cite book|last=Anthonsen|first=Thorlief|title=Applied Biocatalysis|year=2000|publisher=Taylor & Francis|isbn=978-90-5823-024-9|pages=18–59|edition=2nd|editor1=Adlercreutz, Patrick|editor2=Straathof, Adrie J. J.|access-date=9 February 2013|chapter=Reactions Catalyzed by Enzymes|chapter-url=https://books.google.com/books?id=EkLlnS_h01IC&pg=PA18}}</ref><ref>{{cite book|last=Faber|first=Kurt|title=Biotransformations in Organic Chemistry|year=2011|publisher=Springer|isbn=978-3-642-17393-6|edition=6th}}{{page needed|date=February 2013}}</ref><ref>{{cite journal | last=Jayasinghe|first=Leonard Y.|author2=Smallridge, Andrew J. |author3=Trewhella, Maurie A. | title = The yeast mediated reduction of ethyl acetoacetate in petroleum ether | journal = Tetrahedron Letters| year = 1993 | volume = 34 | issue = 24 | pages=3949–3950 | doi = 10.1016/S0040-4039(00)79272-0}}</ref> The modern usage of biotechnologically produced and possibly modified enzymes for [[organic synthesis]] is termed '''chemoenzymatic synthesis'''; the reactions performed are '''chemoenzymatic reactions'''.}}
{{term|term= '''[[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]] and [[medicine]], combining the design and problem solving skills of engineering with medical biological sciences to advance health care treatment, including [[Medical diagnosis|diagnosis]], [[Medical monitor|monitoring]], and [[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 [[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=etal}}</ref>}}
{{term|term= '''[[Bionics]]'''}}{{defn|defn= The application of biological methods to engineering systems.}}
{{term|term= '''[[Biophysics]]'''}}{{defn|defn= Is an interdisciplinary science that applies approaches and methods traditionally used in [[physics]] to study [[Biology|biological]] phenomena.<ref>{{Cite encyclopedia|url=https://www.britannica.com/science/biophysics|title=Biophysics {{!}} science|encyclopedia=Encyclopædia 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 | doi-access = free }}</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 [[Molecule|molecular]] to [[organism]]ic and [[Population (biology)|populations]]. Biophysical research shares significant overlap with [[biochemistry]], [[molecular biology]], [[physical chemistry]], [[physiology]], [[nanotechnology]], [[bioengineering]], [[computational biology]], [[biomechanics]] and [[systems biology]].}}
{{term|term= '''[[Biot number]]'''}}{{defn|defn=The '''Biot number''' ('''Bi''') is a [[dimensionless quantity]] used in heat transfer calculations. It is named after the eighteenth century French physicist [[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= '''[[Block and tackle]]'''}}{{defn|defn=A  system of pulleys and a rope threaded between them, used to lift or pull heavy loads.}}
{{term|term= '''[[Body force]]'''}}{{defn|defn=Is a force that acts throughout the volume of a body. Forces due to [[gravity]], [[electrostatics|electric fields]] and [[magnetic fields]] are examples of body forces. Body forces contrast with [[contact force]]s or [[surface force]]s which are exerted to the surface of an object.}}
{{term|term= '''[[Boiler]]'''}}{{defn|defn=Is a closed [[pressure vessel|vessel]] in which [[fluid]] (generally water) is heated. The fluid does not necessarily [[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 [[Boiler (water heating)|water heating]], [[central heating]], [[boiler (power generation)|boiler-based power generation]], [[cooking]], and [[sanitation]]. }} 
{{term|term= '''[[Boiling point]]'''}}{{defn|defn=The boiling point of a substance is the temperature at which the [[vapor pressure]] of a [[liquid]] equals the [[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= '''[[Boiling-point elevation]]'''}}{{defn|defn='''Boiling-point elevation''' describes the phenomenon that the [[boiling point]] of a [[liquid]] (a [[solvent]]) will be higher when another compound is added, meaning that a [[Solution (chemistry)|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 [[ebullioscope]].}}
{{term|term= '''[[Boltzmann constant]]'''}}{{defn|defn=The '''Boltzmann constant''' ({{math|''k''<sub>B</sub>}} or {{mvar|k}}) is a [[physical constant]] relating the average [[kinetic energy]] of [[particle]]s in a [[ideal gas|gas]] with the [[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=https://feynmanlectures.caltech.edu/I_39.html}}</ref> and occurs in [[Planck's law]] of [[black-body radiation]] and in [[Boltzmann's entropy formula]]. It was introduced by [[Max Planck]], but named after [[Ludwig Boltzmann]].

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

:<math> k = \frac{R}{N_\text{A}} .</math>.}}
{{term|term= '''[[Boson]]'''}}{{defn|defn=In [[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=978-0-582-05383-0 }} 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 [[Bose–Einstein statistics]]. Bosons make up one of the two classes of [[elementary particle|particles]], the other being [[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=978-1-59803-350-2 |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 [[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=978-0-465-01992-2|page=331}}</ref> to commemorate the contribution of Indian physicist and professor of physics at [[University of Calcutta]] and at [[University of Dhaka]], [[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=[[The New York Times]] blog |access-date=21 September 2012}}</ref> in developing, with [[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 [[gas laws|gas law]] that describes how the [[pressure]] of a [[gas]] tends to increase as the [[volume]] of the container decreases. A modern statement of Boyle's law is: 
The absolute pressure exerted by a given mass of an [[ideal gas]] is inversely proportional to the volume it occupies if the [[temperature]] and [[amount of substance|amount of gas]] remain unchanged within a [[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]] and [[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|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 [[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= '''[[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= '''[[Break-even (economics)|Break-even]]'''}}{{defn|defn=The '''break-even point''' (BEP) in [[economics]], [[business]]—and specifically [[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 [[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 | author-link = David K. Levine |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 [[angle of incidence (optics)|angle of incidence]] at which [[light]] with a particular [[Polarization (waves)|polarization]] is perfectly transmitted through a transparent [[dielectric]] surface, with ''no [[Reflection (physics)|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 [[David Brewster|Sir David Brewster]] (1781–1868).<ref>David Brewster (1815) [https://books.google.com/books?id=U-U_AAAAYAAJ&pg=PA125 "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= '''[[Brittleness]]'''}}{{defn|defn=A material is '''brittle''' if, when subjected to [[stress (physics)|stress]], it breaks without significant [[Plastic Deformation|plastic deformation]]. Brittle materials absorb relatively little [[energy]] prior to fracture, even those of high [[Strength of materials|strength]]. Breaking is often accompanied by a snapping sound. Brittle materials include most [[ceramic materials|ceramics]] and [[glass]]es (which do not deform plastically) and some [[polymer]]s, such as [[Polymethyl methacrylate|PMMA]] and [[polystyrene]]. Many [[steel]]s become brittle at low temperatures (see [[Ductility#Ductile–brittle transition temperature|ductile–brittle transition temperature]]), depending on their composition and processing.}}
{{term|term= '''[[Bromide]]'''}}{{defn|defn=Any chemical substance made up of Bromine, along with other elements.}}
{{term|term= '''[[Brønsted–Lowry acid–base theory]]'''}}{{defn|defn=Is an [[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 [[conjugate acid|conjugate base]], and the base forms its conjugate acid by exchange of a [[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 [[particle]]s suspended in a [[fluid]] (a [[liquid]] or a [[gas]]) resulting from their collision with the fast-moving [[molecule]]s in the fluid.<ref name=Feynman-41>
{{cite book
 |last=Feynman |first=R.
 |year=1964
 |chapter=The Brownian Movement
 |chapter-url=https://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 Π groups, or dimensionless descriptors of physical phenomena.}}
{{term|term= '''[[Buffer solution]]'''}}{{defn|defn=A '''buffer solution''' (more precisely, [[pH]] buffer or [[hydrogen ion]] buffer) is an [[aqueous solution]] consisting of a [[mixture]] of a [[weak acid]] and its [[conjugate base]], or vice versa. Its pH changes very little when a small amount of [[strong acid]] or [[Base (chemistry)#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= '''[[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]] [[pressure]] increase to the resulting ''relative'' decrease of the [[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 ([[Strain (materials science)|strain]]) to other kinds of [[Stress (physics)|stress]]: the [[shear modulus]] describes the response to shear, and [[Young's modulus]] describes the response to linear stress. For a [[fluid]], only the bulk modulus is meaningful. For a complex [[anisotropic]] solid such as [[wood]] or [[paper]], these three moduli do not contain enough information to describe its behaviour, and one must use the full generalized [[Hooke's law]].}}
{{term|term= '''[[Buoyancy]]'''}}{{defn|defn=A force caused by displacement in a fluid by an object of different density than the fluid.}} 
{{Glossary of engineering ToC}}
{{glossary end}}

==C==
{{glossary}}
{{term|term= '''[[Calculus]]'''}}{{defn|defn=The mathematics of change.}}
{{term|term= '''[[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= '''[[Capacitor]]'''}}{{defn|defn=An electrical component that stores energy in an electric field.}}
{{term|term= '''[[Capillary action]]'''}}{{defn|defn='''Capillary action''' (sometimes '''capillarity''', '''capillary motion''', '''capillary effect''', or '''wicking''') is the ability of a [[liquid]] to flow in narrow spaces without the assistance of, or even in opposition to, external forces like [[Gravitation|gravity]]. The effect can be seen in the drawing up of liquids between the hairs of a paintbrush, 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 [[intermolecular force]]s between the liquid and surrounding solid surfaces. If the diameter of the tube is sufficiently small, then the combination of [[surface tension]] (which is caused by [[Cohesion (chemistry)|cohesion]] within the liquid) and [[Adhesion|adhesive forces]] between the liquid and container wall act to propel the liquid.}}
{{term|term= '''[[Carbonate]]'''}}{{defn|defn=Any mineral with bound carbon dioxide.}}
{{term|term= '''[[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 [[Linear elasticity|linear-elastic]] system based on the [[partial derivative]]s  of the [[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= '''[[Cathode]]'''}}{{defn|defn=The terminal of a device by which current exits.}}
{{term|term= '''[[Cathode ray]]'''}}{{defn|defn=The stream of electrons emitted from a heated negative electrode and attracted to a positive electrode.}}
{{term|term= '''[[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 [[biological membrane]] that separates the [[cytoplasm|interior]] of all [[Cell (biology)|cells]] from the [[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 [[lipid bilayer]] with embedded [[protein]]s.}}
{{term|term= '''[[Cell nucleus]]'''}}{{defn|defn=In [[cell biology]], the  '''nucleus''' (pl. '''''nuclei'''''; from [[Latin]] {{lang|la|nucleus}} or {{lang|la|nuculeus}}, meaning ''kernel'' or ''seed'') is a [[biological membrane|membrane]]-enclosed [[organelle]] found in [[eukaryote|eukaryotic]] [[cell (biology)|cells]]. Eukaryotes usually have a single nucleus, but a few cell types, such as mammalian red blood cells, have [[#Anucleated_cells|no nuclei]], and a few others including [[osteoclast]]s have [[Multinucleate|many]].}}
{{term|term= '''[[Cell theory]]'''}}{{defn|defn=In [[biology]], '''cell theory''' is the historic [[scientific theory]], now universally accepted, that living organisms are made up of [[Cell (biology)|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= '''[[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 [[pressure]] field acts on a body, causing a [[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]], the '''central limit theorem''' ('''CLT''') establishes that, in some situations, when [[Statistical independence|independent random variables]] are added, their properly normalized sum tends toward a [[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 [[electronic circuit]]ry within a [[computer]] that carries out the [[Instruction (computing)|instructions]] of a [[computer program]] by performing the basic [[arithmetic]], logic, controlling and [[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]] (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= 978-0-471-02716-4|page= 12}}</ref>}}
{{term|term= '''[[Acceleration#Tangential and centripetal acceleration|Centripetal acceleration]]'''}}{{defn|defn=.}}
{{term|term= '''[[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= '''[[Centrosome]]'''}}{{defn|defn=In [[cell biology]], the '''centrosome''' is an [[organelle]] that serves as the main [[microtubule organizing center]] (MTOC) of the animal [[cell (biology)|cell]] as well as a regulator of [[cell-cycle]] progression. The centrosome is thought to have evolved only in the [[metazoa]]n lineage of [[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
 |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.
 |date = 2007
 |chapter-url = https://archive.org/details/eukaryoticmembra00gasp
 |url = https://archive.org/details/eukaryoticmembra00gasp/page/119
}}</ref> [[Fungus|Fungi]] and [[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 = 978-0-12-364624-8 
| 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= '''[[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]] leads to a self-amplifying [[chain of events]].}}
{{term|term= '''[[Change of base rule]]'''}}{{defn|defn=.}}
{{term|term= '''[[Charles's law]]'''}}{{defn|defn='''Charles's law''' (also known as the '''law of volumes''') is an experimental [[gas laws|gas law]] that describes how [[gas]]es [[Thermal expansion|tend to expand when heated]]. A modern statement of Charles's law is:
 When the [[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= '''[[Chemical bond]]'''}}{{defn|defn=Is a lasting attraction between [[atom]]s, [[ions]] or [[molecules]] that enables the formation of [[chemical compound]]s. The bond may result from the [[electrostatic force]] of attraction between oppositely charged ions as in ionic bonds or through the sharing of electrons as in [[covalent bond]]s. The strength of chemical bonds varies considerably; there are "strong bonds" or "primary bonds" such as covalent, [[ionic bond|ionic]] and [[Metallic bonding|metallic]] bonds, and "weak bonds" or "secondary bonds" such as [[dipole–dipole interaction]]s, the [[London dispersion force]] and [[hydrogen bond]]ing.}} 
{{term|term= '''[[Chemical compound]]'''}}{{defn|defn=Is a [[chemical substance]] composed of many identical [[molecule]]s (or [[molecular entity|molecular entities]]) composed of [[atom]]s from more than one [[chemical element|element]] held together by [[chemical bond]]s. A [[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= '''[[Chemical equilibrium]]'''}}{{defn|defn=In a [[chemical reaction]], '''chemical equilibrium''' is the state in which both reactants and products are present in [[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 [[Reversible reaction|reverse reaction]]. The [[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 [[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 |publisher=W.H. Freeman }}</ref><ref>{{GoldBookRef|title=chemical equilibrium|file=C01023}}</ref>}}
{{term|term= '''[[Chemical kinetics]]'''}}{{defn|defn='''Chemical kinetics''', also known as '''reaction kinetics''', is the study of [[reaction rate|rates]] of [[chemical process]]es. Chemical kinetics includes investigations of how different experimental conditions can influence the speed of a [[chemical reaction]] and yield information about the [[reaction mechanism|reaction's mechanism]] and [[transition state]]s, as well as the construction of [[mathematical model]]s that can describe the characteristics of a chemical reaction.}}
{{term|term= '''[[Chemical reaction]]'''}}{{defn|defn=A '''chemical reaction''' is a process that leads to the [[IUPAC nomenclature for organic transformations|chemical transformation]] of one set of [[chemical substance]]s to another.<ref>{{GoldBookRef|title=chemical reaction|file=C01033}}</ref> Classically, chemical reactions encompass changes that only involve the positions of [[electron]]s in the forming and breaking of [[chemical bond]]s between [[atom]]s, with no change to the nuclei (no change to the elements present), and can often be described by a [[chemical equation]]. [[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]]'''}}{{defn|defn=Is the [[scientific discipline]] involved with [[Chemical element|elements]] and [[chemical compound|compounds]] composed of [[atom]]s, [[molecule]]s and [[ion]]s: their composition, structure, properties, behavior and the changes they undergo during a [[Chemical reaction|reaction]] with other [[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 |archive-date=3 October 2018 |archive-url=https://web.archive.org/web/20181003061822/http://chemweb.ucc.ie/what_is_chemistry.htm  }}</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=[[American Chemical Society]]}}</ref>}}
{{term|term= '''[[Chloride]]'''}}{{defn|defn=Any chemical compound containing the element chlorine.}} 
{{term|term= '''[[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 [[oxyanion]]s of [[chromium]] in the 6+ [[oxidation state]] . They are moderately strong [[oxidizing agent]]s. In an [[aqueous]] [[Solution (chemistry)|solution]], chromate and dichromate ions can be interconvertible.}}
{{term|term= '''[[Circular motion]]'''}}{{defn|defn=In [[physics]], circular motion is a movement of an object along the [[circumference]] of a [[circle]] or [[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]] of a three-dimensional body involves circular motion of its parts. The equations of motion describe the movement of the [[center of mass]] of a body.}}
{{term|term= '''[[Civil engineering]]'''}}{{defn|defn=The profession that deals with the design and construction of structures, or other fixed works.}}
{{term|term= '''[[Clausius–Clapeyron relation]]'''}}{{defn|defn=The '''Clausius–Clapeyron relation''', named after [[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 [[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 [[phase transition]] between two [[phases of matter]] of a single constituent. On a [[pressure]]–[[temperature]] (P–T) diagram, the line separating the two phases is known as the coexistence curve. The Clausius–Clapeyron relation gives the [[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 [[latent heat]], <math>T</math> is the [[temperature]], <math>\Delta v </math> is the [[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= '''[[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 [[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 [[Wolfram Research]]</ref> The reversible case is used to introduce the [[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= '''[[Coefficient of performance]]'''}}{{defn|defn=The '''coefficient of performance''' or '''COP''' (sometimes '''CP''' or '''CoP''') of a [[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  |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  |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]] and [[statistics]], the '''coefficient of variation''' ('''CV'''), also known as '''relative standard deviation''' ('''RSD'''), is a [[Standardized (statistics)|standardized]] measure of [[statistical dispersion|dispersion]] of a [[probability distribution]] or [[frequency distribution]]. It is often expressed as a percentage, and is defined as the ratio of the [[standard deviation]]  <math>\ \sigma </math> to the [[mean]]  <math>\ \mu </math> (or its [[absolute value]], <math>| \mu |</math>).}}
{{term|term= '''[[Coherence (physics)|Coherence]]'''}}{{defn|defn=In [[physics]], two wave sources are perfectly coherent if they have a constant [[phase difference]] and the same [[frequency]], and the same [[waveform]]. Coherence is an ideal property of [[wave]]s that enables stationary (i.e. temporally and spatially constant) [[Interference (wave propagation)|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= '''[[Cohesion (chemistry)|Cohesion]]'''}}{{defn|defn=Or '''cohesive attraction''' or '''cohesive force''' is the action or [[chemical property|property]] of like [[molecule]]s sticking together, being mutually [[intermolecular attraction|attractive]]. It is an intrinsic property of a [[Chemical substance|substance]] that is caused by the shape and structure of its molecules, which makes the distribution of orbiting [[electron]]s irregular when molecules get close to one another, creating [[Coulomb force|electrical attraction]] that can maintain a microscopic structure such as a [[drop (liquid)|water drop]]. In other words, cohesion allows for [[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= '''[[Combustion]]'''}}{{defn|defn=Or '''burning''',<ref>colloquial meaning of burning is combustion accompanied by flames</ref> is a high-temperature [[exothermic]] [[redox]] [[chemical reaction]] between a [[fuel]] (the reductant) and an [[oxidant]], usually atmospheric [[oxygen]], that produces oxidized, often gaseous products, in a mixture termed as [[smoke]].}}
{{term|term= '''Compensation'''}}{{defn|defn=Is planning for side effects or other unintended issues in a [[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]] can itself also be to compensate for some other existing issue or [[Action (philosophy)|exception]].}}
{{term|term= '''[[Compiler]]'''}}{{defn|defn=A computer program that translates a high-level language into machine language.}} 
{{term|term= '''[[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 [[Ultimate tensile strength|tensile strength]], which withstands loads tending to elongate. In other words, compressive strength resists [[Compression (physics)|compression]] (being pushed together), whereas tensile strength resists [[Tension (physics)|tension]] (being pulled apart). In the study of [[strength of materials]], tensile strength, compressive strength, and [[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]] or [[Boolean algebra|logical]] operations automatically via [[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= '''[[Computer-aided design]]'''}}{{defn|defn='''Computer-aided design''' ('''CAD''') is the use of [[computer system]]s (or {{vanchor|[[workstation]]s|WORKSTATION}}) to aid in the creation, modification, analysis, or optimization of a [[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=978-81-203-3342-0}}</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=978-81-203-3342-0}}</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=978-0-9629165-9-5 |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]] analysis tasks. It includes {{nowrap|[[finite element analysis]] (FEA)}}, {{nowrap|[[computational fluid dynamics]] (CFD)}}, {{nowrap|[[multibody dynamics]] (MBD)}}, [[durability]] and [[optimization]].}}
{{term|term= '''[[Computer-aided manufacturing]]'''}}{{defn|defn='''Computer-aided manufacturing''' ('''CAM''') is the use of  software to control [[machine tool]]s and related ones in the [[manufacturing]] of workpieces.<ref name="ota">{{cite book | last = [[U.S. Congress]], [[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 | author-link= Frank Kreith | 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]] and [[electronics engineering]] required to develop computer hardware and [[computer software|software]].<ref>{{Cite book
 |last         = IEEE Computer Society
 |author-link  = IEEE Computer Society
 |author2      = ACM
 |author-link2 = Association for Computing Machinery
 |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).
 |archive-date = June 12, 2019
 |archive-url  = https://web.archive.org/web/20190612130313/https://www.acm.org/education/education/curric_vols/CE-Final-Report.pdf
 
}}</ref>}}
{{term|term= '''[[Computer science]]'''}}{{defn|defn=Is the theory, experimentation, and engineering that form the basis for the design and use of [[computer]]s. It involves the study of [[algorithm]]s that process, store, and communicate [[digital data|digital]] [[information]]. A [[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 [[wikt:convex|convex]]. If both surfaces have the same radius of curvature, the lens is ''equiconvex''. A lens with two [[wikt:concave|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= '''[[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 [[frequentist statistics|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. | author-link = Jerzy Neyman | 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= '''[[Conjugate acid]]'''}}{{defn|defn=A '''conjugate acid''', within the [[Brønsted–Lowry acid–base theory]], is a [[Chemical species|species]] formed by the [[protonation|reception of a proton]] ([[Hydron (chemistry)|H<sup>+</sup>]]) by a [[base (chemistry)|base]]—in other words, it is a base with a [[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 [[deprotonation|removal of a proton]] from an acid.<ref name="Zumdahl, Stephen S. 2007" /> Because [[Polyprotic acid|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 [[Brønsted–Lowry acid–base theory]], is a [[Chemical species|species]] formed by the [[protonation|reception of a proton]] ([[Hydron (chemistry)|H<sup>+</sup>]]) by a [[base (chemistry)|base]]—in other words, it is a base with a [[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 [[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|0-618-71370-0}}</ref> Because [[Polyprotic acid|some acids]] are capable of releasing multiple protons, the conjugate base of an acid may itself be acidic.}}
{{term|term= '''[[Conservation of energy]]'''}}{{defn|defn=In physics and chemistry, the '''law of conservation of energy''' states that the total [[energy]] of an [[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=https://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= '''[[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 [[matter]] and [[energy]], the [[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]] that describes the transport of some quantity. It is particularly simple and powerful when applied to a [[conserved quantity]], but it can be generalized to apply to any [[Intensive and extensive properties|extensive quantity]]. Since [[mass]], [[energy]], [[momentum]], [[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= '''[[Continuum mechanics]]'''}}{{defn|defn= Is a branch of [[mechanics]] that deals with the mechanical behavior of materials modeled as a continuous mass rather than as discrete particles. The French mathematician [[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]] 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]] 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 [[wikt:convex|convex]]. If both surfaces have the same radius of curvature, the lens is ''equiconvex''. A lens with two [[wikt:concave|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= '''[[Corrosion]]'''}}{{defn|defn=Is a [[Erosion|natural process]], which converts a refined metal to a more chemically-stable form, such as its [[oxide]], [[hydroxide]], or [[sulfide]]. It is the gradual destruction of materials (usually [[metal]]s) by chemical and/or electrochemical reaction with their environment. [[Corrosion engineering]] is the field dedicated to controlling and stopping corrosion.}}
{{term|term= '''[[Cosmic rays]]'''}}{{defn|defn='''Cosmic rays''' are [[ionizing radiation|high-energy radiation]], mainly originating outside the [[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 [[electric charge]]. It is the charge (symbol: ''Q'' or ''q'') transported by a constant current of one [[ampere]] in one [[second]]:
:<math>1 ~ \text{C} = 1 ~ \text{A} \cdot 1 ~ \text{s}</math>

Thus, it is also the amount of excess charge on a [[capacitor]] of one [[farad]] charged to a potential difference of one [[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]]) [[proton]]s, and −1&nbsp;C is equivalent to the charge of approximately {{val|6.242|e=18}} [[electron]]s.

A [[2019 redefinition of SI base units|new definition]], in terms of the [[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 2018.
 |url=https://www.bipm.org/utils/en/pdf/CGPM/Draft-Resolution-A-EN.pdf
 |access-date=2019-01-05
 |archive-date=2018-04-29
 |archive-url=https://web.archive.org/web/20180429025229/https://www.bipm.org/utils/en/pdf/CGPM/Draft-Resolution-A-EN.pdf
 
 }}</ref> The new definition, defines the [[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= '''[[Coulomb's law]]'''}}{{defn|defn='''Coulomb's law''', or '''Coulomb's inverse-square law''', is a [[physical law|law]] of [[physics]] for quantifying Coulomb's force, or electrostatic force. Electrostatic force is the amount of force with which stationary, [[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 [[classical electromagnetism]]. The law was first published in 1785 by French physicist [[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 [[scalar (physics)|scalar]] form, the law is:

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

where ''k''{{sub|''e''}} is the [[Coulomb 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]], the law is analogous to [[Isaac Newton]]'s inverse-square [[Newton's law of universal gravitation|law of universal gravitation]]. Coulomb's law can be used to derive [[Gauss's law]], and vice versa.}} 
{{term|term= '''[[Covalent bond]]'''}}{{defn|defn=A '''covalent bond''', also called a '''molecular bond''', is a [[chemical bond]] that involves the sharing of [[electron pair]]s between [[atom]]s.}}
{{term|term= '''[[Crookes tube]]'''}}{{defn|defn=A type of vacuum tube that demonstrates cathode rays.}}
{{term|term= '''[[Cryogenics]]'''}}{{defn|defn=The science of low temperatures.}}
{{term|term= '''[[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 [[crystal]]. Some of the ways by which crystals form are  [[Precipitation (chemistry)|precipitating]] from a [[Solution (chemistry)|solution]], [[freezing]], or more rarely [[deposition (physics)|deposition]] directly from a [[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= '''[[Crystallography]]'''}}{{defn|defn=The study of crystals.}} 
{{term|term= '''[[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= '''[[Cyclotron]]'''}}{{defn|defn=A '''cyclotron''' is a type of [[particle accelerator]] invented by [[Ernest O. Lawrence]] in 1929–1930 at the [[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 [[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=etal}}</ref> The particles are held to a spiral trajectory by a static magnetic field and accelerated by a rapidly varying ([[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}}
{{Glossary of engineering ToC}}

==D==
{{glossary}}
{{term|term= '''[[Dalton's law]]'''}}{{defn|defn=In [[chemistry]] and [[physics]], '''Dalton's law''' (also called '''Dalton's law of partial pressures''') states that in a mixture of non-reacting gases, the total  [[pressure]] exerted is equal to the sum of the [[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=978-0-07-304859-8 |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= '''[[DC motor]]'''}}{{defn|defn=An electrical motor driven by direct current.}}
{{term|term= '''[[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= '''[[Deflection (engineering)|Deflection]]'''}}{{defn|defn=Is the degree to which a structural element is displaced under a [[force|load]]. It may refer to an angle or a distance.}}
{{term|term= '''[[Deformation (engineering)]]'''}}{{defn|defn=In [[materials science]], '''deformation''' refers to any changes in the shape or size of an object due to 
* an applied [[force (physics)|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 [[tensile strength|tensile]] (pulling) forces, [[compressive strength|compressive]] (pushing) forces, [[Simple shear|shear]], [[bending]] or [[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= '''[[Deformation (mechanics)]]'''}}{{defn|defn='''Deformation''' in [[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> [[body force]]s (such as [[gravity]] or [[electromagnetic force]]s), or changes in temperature, moisture content, or chemical reactions, etc.}}
{{term|term= '''[[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= '''[[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]], the '''de Moivre–Laplace theorem''', which is a special case of the [[central limit theorem]], states that the [[normal distribution]] may be used as an approximation to the [[binomial distribution]] under certain conditions. In particular, the theorem shows that the [[probability mass function]] of the random number of "successes" observed in a series of <math>n</math> [[statistical independence|independent]] [[Bernoulli trial]]s, each having probability <math>p</math> of success (a binomial distribution with <math>n</math> trials), [[Convergence in distribution|converges]] to the [[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= '''[[Density]]'''}}{{defn|defn=
The '''density''', or more precisely, the '''volumetric mass density''', of a substance is its [[mass]] per unit [[volume]]. The symbol most often used for density is ''ρ'' (the lower case Greek letter [[Rho (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 =''[[National Aeronautic and Space Administration|The National Aeronautic and Atmospheric Administration's]]'' ''[[Glenn Research Center]]'' | publisher =grc.nasa.gov  | archive-url =https://web.archive.org/web/20130414132531/http://www.grc.nasa.gov/WWW/BGH/fluden.html | archive-date =April 14, 2013 | 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 [[weight]] per unit [[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  |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 [[specific weight]].}} 
{{term|term= '''[[Derivative]]'''}}{{defn|defn=The '''derivative''' of a [[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]]. For example, the derivative of the position of a moving object with respect to [[time]] is the object's [[velocity]]: this measures how quickly the position of the object changes when time advances.}}
{{term|term= '''[[Design engineering]]'''}}{{defn|defn=.}}
{{term|term= '''[[Dew point]]'''}}{{defn|defn= The pressure and temperature at which air is holding the maximum possible humidity.}}
{{term|term= '''[[Diamagnetism]]'''}}{{defn|defn='''Diamagnetic''' materials are repelled by a [[magnetic field]]; an applied magnetic field creates an [[induced magnetic field]] in them in the opposite direction, causing a repulsive force. In contrast, [[paramagnetic]] and [[ferromagnetic]] materials are attracted by a magnetic field. '''Diamagnetism''' is a [[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 [[magnetic dipole]]s in the material. The [[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 [[superconductivity|superconductor]] acts as a strong diamagnet because it repels a magnetic field entirely from its interior.}}
{{term|term= '''[[Dielectric]]'''}}{{defn|defn=An insulator, a material that does not permit free flow of electricity.}}
{{term|term= '''[[Pressure measurement#Absolute, gauge and differential pressures — zero reference|Differential pressure]]'''}}{{defn|defn=.}}
{{term|term= '''[[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 [[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 [[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= '''[[Differential signaling]]'''}}{{defn|defn=Is a method for electrically transmitting [[information]] using two complementary [[Signal (electrical engineering)|signals]].}}
{{term|term= '''[[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 [[base quantity|base quantities]] (such as [[length]], [[mass]], [[time]], and [[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]] 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]].<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]] 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 [[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]] from the horizontal, <math> \theta</math>, is the integral of the internal moment divided by the product of the [[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= '''[[Dispersion (optics)|Dispersion]]'''}}{{defn|defn=In [[optics]], '''dispersion''' is the phenomenon in which the [[phase velocity]] of a wave depends on its frequency.<ref>{{cite book
|last1= Born
|first1= Max
|author-link= Max Born
|last2= Wolf
|first2= Emil
|title= [[Principles of Optics]]
|publisher= [[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 [[light]] and other [[electromagnetic wave]]s, dispersion in the same sense can apply to any sort of wave motion such as [[acoustic dispersion]] in the case of sound and seismic waves, in [[gravity wave]]s (ocean waves), and for telecommunication signals along [[transmission line]]s (such as [[coaxial cable]]) or [[optical fiber]].}}
{{term|term= '''[[Displacement (fluid)]]'''}}{{defn|defn=In [[fluid mechanics]], '''displacement''' occurs when an object is immersed in a [[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]] 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]] of how far apart objects are.}}
{{term|term= '''[[Doppler effect]]'''}}{{defn|defn=The '''Doppler effect''' (or the '''Doppler shift''') is the change in [[frequency]] or [[wavelength]] of a [[wave]] in relation to an [[observer (physics)|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 = 978-0-534-42471-8
 }}</ref> It is named after the [[Austria]]n physicist [[Christian Doppler]], who described the phenomenon in 1842.}}
{{term|term= '''[[Dose–response relationship]]'''}}{{defn|defn=The dose–response relationship, or exposure–response relationship, describes the magnitude of the [[Stimulus–response model|response]] of an [[organism]], as a [[Function (mathematics)|function]] of exposure (or [[Dose (biochemistry)|doses]]) to a [[Stimulus (physiology)|stimulus]] or [[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= '''[[Drag (physics)|Drag]]'''}}{{defn|defn=In [[fluid dynamics]], '''drag''' (sometimes called '''air resistance''', a type of [[friction]], or '''fluid resistance''', another type of friction or fluid friction) is a [[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 [[solid]] surface. Unlike other resistive forces, such as dry [[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}}</ref>
Drag force is proportional to the velocity for a [[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 [[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 [[Pathline|path]].}}
{{term|term= '''[[Drift current]]'''}}{{defn|defn=In [[condensed matter physics]] and [[electrochemistry]], '''drift current''' is the [[electric current]], or movement of [[charge carrier]]s, which is due to the applied [[electric field]], often stated as the [[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= '''[[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= '''[[Dynamics (mechanics)|Dynamics]]'''}}{{defn|defn=Is the [[Branch (academia)#Physics|branch]] of [[classical mechanics]] concerned with the study of [[force (physics)|force]]s and their effects on [[Motion (physics)|motion]]. [[Isaac Newton]] defined the fundamental [[physical law]]s which govern dynamics in physics, especially his [[second law of motion]].}}
{{term|term= '''[[Dyne]]'''}}{{defn|defn=Is a derived [[Units of measurement|unit]] of [[Force (physics)|force]] specified in the [[CGS|centimetre–gram–second (CGS) system of units]], a predecessor of the modern [[International System of Units|SI]]. }}
{{glossary end}}
{{Glossary of engineering ToC}}

==E==
{{glossary}}
{{term|term= '''[[Economics]]'''}}{{defn|defn=The scientific study of the production, distribution and consumption of goods.}}
{{term|term= '''[[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 [[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= '''[[Elastic modulus]]'''}}{{defn|defn= The amount a material will deform per unit force.}} 
{{term|term= '''[[Elasticity (physics)|Elasticity]]'''}}{{defn|defn=In [[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 [[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= '''[[Electric charge]]'''}}{{defn|defn=is the [[physical property]] of [[matter]] that causes it to experience a [[force]] when placed in an [[electromagnetic field]]. There are two types of electric charges; ''positive'' and ''negative'' (commonly carried by [[proton]]s and [[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 [[classical electrodynamics]], and is still accurate for problems that do not require consideration of [[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= '''[[Electric current]]'''}}{{defn|defn= Is a flow of [[electric charge]].<ref name="horowitz">{{cite book|title=The art of electronics|last1=Horowitz|first1=Paul|last2=Hill|first2=Winfield|author-link1=Paul Horowitz (scientist)|author-link2=Winfield Hill|date=2015|publisher=[[Cambridge University Press]]|isbn=978-0-521-80926-9|edition=3rd}}</ref>{{rp|2}} In [[electric circuit]]s this charge is often carried by moving [[electron]]s in a [[wire]]. It can also be carried by [[ion]]s in an [[Electrolyte#Electrochemistry|electrolyte]], or by both ions and electrons such as in an ionised gas ([[Plasma (physics)|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]], which is the flow of electric charge across a surface at the rate of one [[coulomb]] per second. Electric current is measured using a device called an [[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
 
 |archive-url = https://web.archive.org/web/20090227065653/http://library.thinkquest.org/10796/ch13/ch13.htm
 |archive-date = 2009-02-27
}}</ref>}}
{{term|term= '''[[Electric displacement field]]'''}}{{defn|defn=In [[physics]], the '''electric displacement field''', denoted by '''D''', is a [[vector field]] that appears in [[Maxwell's equations]]. It accounts for the effects of [[Charge density#Free, bound and total charge|free and bound charge]] within materials. "'''D'''" stands for "displacement", as in the related concept of [[displacement current]] in [[dielectric]]s. In [[free space]], the electric displacement field is equivalent to [[flux#Electric flux|flux density]], a concept that lends understanding to [[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= '''[[Electric generator]]'''}}{{defn|defn=In [[electricity generation]], a '''generator''',also called '''electric generator''', '''electrical generator''', and '''electromagnetic generator'''. is a device that converts motive power ([[mechanical energy]]) into [[electrical power]] for use in an external [[electrical circuit|circuit]]. Sources of mechanical energy include [[steam turbine]]s, [[gas turbine]]s, [[water turbine]]s, [[internal combustion engine]]s and even hand [[crank (mechanism)|crank]]s. }}
{{term|term= '''[[Electric field]]'''}}{{defn|defn=Surrounds an [[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= '''[[Electric field gradient]]'''}}{{defn|defn=In [[atomic physics|atomic]], [[molecular physics|molecular]], and [[solid-state physics]], the '''electric field gradient''' ('''EFG''') measures the rate of change of the [[electric field]] at an [[atomic nucleus]] generated by the [[electron]]ic [[charge distribution]] and the other nuclei.}}
{{term|term= '''[[Electric motor]]'''}}{{defn|defn=Is an [[electric machine|electrical machine]] that converts [[electrical energy]] into [[mechanical energy]]. Most electric motors operate through the interaction between the motor's [[magnetic field]] and [[electrical conductor|winding currents]] to generate force in the form of [[rotation]]. Electric motors can be powered by [[direct current]] (DC) sources, such as from batteries, motor vehicles or rectifiers, or by [[alternating current]] (AC) sources, such as a power grid, [[Inverter (electrical)|inverters]] or electrical generators. An [[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= '''[[Electric potential]]'''}}{{defn|defn=(Also called the ''electric field potential'', potential drop or the '''electrostatic potential''') is the amount of [[work (physics)|work]] needed to move a unit  of [[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 (electricity)|Earth]] or a point at [[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 [[potential energy]] (measured in [[joule]]s) that results from [[conservative force|conservative]] [[Coulomb force]]s and is associated with the configuration of a particular set of point [[electric charge|charges]] within a defined [[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]] [[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= '''[[Electric power]]'''}}{{defn|defn=Is the rate, per unit time, at which [[electrical energy]] is transferred by an [[electric circuit]]. The [[SI]] unit of [[power (physics)|power]] is the [[watt]], one [[joule]] per [[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 [[electricity]], [[electronics]], and [[electromagnetism]]. It emerged as an identified activity in the latter half of the 19th century after [[commercialization]] of the [[electric telegraph]], the [[telephone]], and [[electrical power]] generation, distribution and use. .}}
{{term|term= '''[[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 [[friction]]. The [[International System of Units|SI]] unit of electrical resistance is the [[ohm]] ([[Omega|Ω]]), while electrical conductance is measured in [[siemens (unit)|siemens]] (S).}}
{{term|term= '''[[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= '''[[Electrical impedance]]'''}}{{defn|defn=Is the measure of the opposition that a [[electrical circuit|circuit]] presents to a [[electric current|current]] when a [[voltage]] is applied. The term ''complex impedance'' may be used interchangeably.}}
{{term|term= '''[[Electrical insulator]]'''}}{{defn|defn=Is a material whose internal [[electric charge]]s do not flow freely; very little [[electric current]] will flow through it under the influence of an [[electric field]]. This contrasts with other materials, [[semiconductor]]s and [[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= '''[[Electrical network]]'''}}{{defn|defn=Is an interconnection of [[electronic component|electrical component]]s (e.g., [[battery (electricity)|batteries]], [[resistor]]s, [[inductor]]s, [[capacitor]]s, [[switch]]es, [[transistor]]s) or a model of such an interconnection, consisting of [[electrical element]]s (e.g., [[voltage source]]s, [[current source]]s, [[Electrical resistance and conductance|resistance]]s, [[inductance]]s, [[capacitance]]s). An electrical circuit is a network consisting of a closed loop, giving a return path for the current. [[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]] methods such as [[Laplace transform]]s, to determine [[direct current|DC response]], [[alternating current|AC response]], and [[transient response]].}}
{{term|term= '''[[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 [[friction]]. The [[International System of Units|SI]] unit of electrical resistance is the [[ohm]] ([[Omega|Ω]]), while electrical conductance is measured in [[siemens (unit)|siemens]] (S).}}
{{term|term= '''[[Electricity]]'''}}{{defn|defn=Is the set of [[physics|physical]] [[Phenomenon|phenomena]] associated with the presence and [[motion]] of [[matter]] that has a property of [[electric charge]]. Electricity is related to [[magnetism]], both being part of the phenomenon of [[electromagnetism]], as described by [[Maxwell's equations]]. Various common phenomena are related to electricity, including [[lightning]], [[static electricity]], [[electric heating]], [[electric discharge]]s and many others.}}
{{term|term= '''[[Electrodynamics]]'''}}{{defn|defn=In physics, the phenomena associated with moving [[electric charge]]s, and their [[Electromagnetism|interaction]] with [[electric]] and [[magnetic]] fields; the study of these phenomena.<ref>[https://en.wiktionary.org/wiki/electrodynamics Wiktionary]</ref>}}
{{term|term= '''[[Electromagnet]]'''}}{{defn|defn=Is a type of [[magnet]] in which the [[magnetic field]] is produced by an [[electric current]]. Electromagnets usually consist of wire wound into a [[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 [[magnetic core]] made from a [[ferromagnetic]] or [[ferrimagnetic]] material such as [[iron]]; the magnetic core concentrates the [[magnetic flux]] and makes a more powerful magnet.}}
{{term|term= '''[[Electromagnetic field]]'''}}{{defn|defn=An electromagnetic field (also ''EM field'') is a classical (i.e. non-quantum) [[field (physics)|field]] produced by accelerating [[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=https://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 [[classical electrodynamics]] and is the classical counterpart to the [[electromagnetic field tensor|quantized electromagnetic field tensor]] in [[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 [[electromagnetic field tensor|quantum counterpart]] is one of the four [[fundamental force]]s of nature (the others are [[gravitation]], [[weak interaction]] and [[strong interaction]].)}}
{{term|term= '''[[Electromagnetic radiation]]'''}}{{defn|defn=In [[physics]], electromagnetic radiation (''EM radiation'' or ''EMR'') refers to the waves (or their [[Quantum|quanta]], [[photon]]s) of the [[electromagnetic field]], propagating (radiating) through space, carrying electromagnetic [[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]]s, [[microwave]]s, [[infrared]], [[Light|(visible) light]], [[ultraviolet]], [[X-ray]]s, and [[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= '''[[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 (Scientist)|Fitzhugh Townsend]]. 1901.</ref><ref>{{cite journal | author1=Szolc T. |author2-link=Robert Konowrocki (Scientist) |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 |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 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|author1-link=Robert Konowrocki (Scientist) |bibcode=2016MSSP...70..397K }}</ref> combines processes and procedures drawn from [[electrical engineering]] and [[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 ([[Electric generator|generator]]) or used to power a mechanical effect ([[Electric motor|motor]]). Electrical engineering in this context also encompasses [[electronic engineering|electronics engineering]].}}
{{term|term= '''[[Electron]]'''}}{{defn|defn=Is a [[subatomic particle]], symbol {{SubatomicParticle|Electron}} or {{SubatomicParticle|beta-}}, whose [[electric charge]] is negative one [[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 [[generation (particle physics)|generation]] of the [[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 [[elementary particle]]s because they have no known components or substructure.<ref>{{cite journal | last1=Eichten | first1=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 | s2cid=119918703 }} OSTI 1446807.</ref> The electron has a [[Invariant mass|mass]] that is approximately [[Proton-to-electron mass ratio|1/1836]] that of the [[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> [[Quantum mechanics|Quantum mechanical]] properties of the electron include an intrinsic [[angular momentum]] ([[Spin (physics)|spin]]) of a half-integer value, expressed in units of the [[reduced Planck constant]], ''ħ''. Being [[fermion]]s, no two electrons can occupy the same [[quantum state]], in accordance with the [[Pauli exclusion principle]].<ref name="curtis74"/> Like all elementary particles, electrons exhibit properties of [[wave-particle duality|both particles and waves]]: they can collide with other particles and can be [[electron diffraction|diffracted]] like light. The [[#Quantum properties|wave properties of electrons]] are easier to observe with experiments than those of other particles like [[neutron]]s and protons because electrons have a lower mass and hence a longer [[de Broglie wavelength]] for a given energy.}}
{{term|term= '''[[Electronvolt]]'''}}{{defn|defn=In [[physics]], an electronvolt (symbol eV, also written ''electron-volt'' and ''electron volt'') is the amount of [[kinetic energy]] gained by a single [[electron]] accelerating from rest through an [[Voltage|electric potential difference]] of one [[volt]] in vacuum. When used as a [[Units of energy|unit of energy]], the numerical value of 1 eV in [[joule]]s (symbol J) is equivalent to the numerical value of the charge of an electron in [[coulomb]]s (symbol C). Under the [[2019 redefinition of the SI base units]], this sets 1 eV equal to the exact value {{physconst|eV|after=.}}}}
{{term|term= '''[[Electron pair]]'''}}{{defn|defn=In [[chemistry]], an electron pair, or ''Lewis pair'', consists of two [[electron]]s that occupy the same [[molecular orbital]] but have opposite [[Spin (physics)|spins]]. [[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= '''[[Electronegativity]]'''}}{{defn|defn=Symbolized as <span class="nounderlines">''[[Chi (letter)|χ]]''</span>, is the measurement of the tendency of an [[atom]] to attract a shared pair of [[electron]]s (or [[electron density]]).<ref name="definition">{{GoldBookRef|file=E01990|title=Electronegativity}}</ref> An atom's electronegativity is affected by both its [[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= '''[[Electronics]]'''}}{{defn|defn=Comprises the physics, engineering, technology and applications that deal with the emission, flow and control of [[electron]]s in [[vacuum]] and [[matter]].<ref>{{Cite encyclopedia|url=https://www.britannica.com/technology/electronics|title=electronics {{!}} Devices, Facts, & History|encyclopedia=Encyclopædia Britannica|access-date=2018-09-19}}</ref> It uses active devices to control electron flow by [[amplifier|amplification]] and [[rectifier|rectification]], which distinguishes it from  classical [[electrical engineering]] which uses passive effects such as [[Electrical resistance and conductance|resistance]], [[capacitance]] and [[inductance]] to control [[Electric current|current]] flow.}}
{{term|term= '''[[Elemental analysis]]'''}}{{defn|defn=Is a process where a sample of some material (e.g., soil, waste or drinking water, bodily fluids, [[minerals]], [[chemical compound]]s) is analyzed for its [[chemical element|elemental]] and sometimes [[isotope|isotopic]] composition.{{citation needed|date=February 2019}} Elemental analysis can be qualitative (determining what elements are present), and it can be quantitative (determining how much of each are present). Elemental analysis falls within the ambit of [[analytical chemistry]], the set of instruments involved in deciphering the chemical nature of our world.}} 
{{term|term= '''[[Endothermic process]]'''}}{{defn|defn=Is any process with an increase in the [[enthalpy]] ''H'' (or [[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|978-1-305-07911-3}}</ref> In such a process, a closed system usually absorbs [[thermal energy]] from its surroundings, which is [[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= '''[[Energy]]'''}}{{defn|defn=In [[physics]], energy is the [[physical quantity|quantitative]] [[physical property|property]] that must be [[#Energy transfer|transferred]] to an [[Physical body|object]] in order to perform [[Work (thermodynamics)|work]] on, or to [[heat]], the object.<ref group=note>The [[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|[[waste heat|consumed]]}} in the form of [[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 [[conservation of energy]] states that energy can be [[Energy transformation|converted]] in form, but not created or destroyed. The [[International System of Units|SI unit]] of energy is the [[joule]], which is the energy transferred to an object by the [[work (physics)|work]] of moving it a distance of 1 [[metre]] against a [[force]] of 1 [[newton (unit)|newton]].}}
{{term|term= '''[[Engine]]'''}}{{defn|defn=An engine or ''motor'' is a [[machine]] designed to convert one form of [[energy]] into [[Motion (physics)|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> [[Heat engine]]s convert [[heat]] into work via various thermodynamic processes. The [[internal combustion engine]] is perhaps the most common example of a heat engine, in which heat from the [[combustion]] of a [[fuel]] causes rapid pressurisation of the gaseous combustion products in the combustion chamber, causing them to expand and drive a [[piston]], which turns a [[crankshaft]]. [[Electric motor]]s convert electrical energy into [[machine (mechanical)|mechanical]] motion, [[pneumatic motor]]s use [[compressed air]], and [[clockwork motor]]s in [[wind-up toy]]s use [[elastic energy]]. In biological systems, [[molecular motor]]s, like [[myosin]]s in [[muscle]]s, use [[chemical energy]] to create forces and ultimately motion.}}
{{term|term= '''[[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>{{cite web |title=definition of "engineering" |url=https://dictionary.cambridge.org/dictionary/english/ |work=Cambridge Academic Content Dictionary |publisher=Cambridge University}}</ref> The discipline of engineering encompasses a broad range of more specialized [[List of engineering branches|fields of engineering]], each with a more specific emphasis on particular areas of [[applied mathematics]], [[applied science]], and types of application. The term ''engineering'' is derived from the [[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= '''[[Engineering economics]]'''}}{{defn|defn=Engineering economics, previously known as ''engineering economy'', is a subset of [[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 [[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]], [[mathematics]] and [[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]]. The field examines and sets the obligations by [[engineer]]s to [[society]], to their clients, and to the profession. As a scholarly discipline, it is closely related to subjects such as the [[philosophy of science]], the [[philosophy of engineering]], and the [[ethics of technology]].}}
{{term|term= '''[[Environmental engineering]]'''}}{{defn|defn=Is a job type that is a professional engineering [[discipline]] and takes from broad [[Science|scientific]] topics like [[chemistry]], [[biology]], [[ecology]], [[geology]], [[hydraulics]], [[hydrology]], [[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|archive-date=2021-02-24|archive-url=https://web.archive.org/web/20210224142618/https://www.aaees.org/careers/}}</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 [[civil engineering]] and [[chemical engineering]].}}
{{term|term= '''[[Engineering physics]]'''}}{{defn|defn=Or ''engineering science'', refers to the study of the combined disciplines of [[physics]], [[mathematics]], [[chemistry]], [[biology]], and [[engineering]], particularly computer, nuclear, electrical, electronic, aerospace, materials or mechanical engineering. By focusing on the [[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= '''[[Enzyme]]'''}}{{defn|defn=Enzymes are [[protein]]s that act as [[biological]] [[catalyst]]s (biocatalysts). Catalysts accelerate [[chemical reactions]]. The molecules upon which enzymes may act are called [[substrate (chemistry)|substrates]], and the enzyme converts the substrates into different molecules known as [[product (chemistry)|products]]. Almost all [[metabolism|metabolic processes]] in the [[cell (biology)|cell]] need [[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= '''[[Escape velocity]]'''}}{{defn|defn=The minimum velocity at which an object can escape a gravitation field.}} 
{{term|term= '''[[Estimator]]'''}}{{defn|defn=In [[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]]) and its result (the estimate) are distinguished.<ref>{{cite book |last1=Mosteller |first1=F. |last2=Tukey |first2=J. W. |orig-date=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]] is a commonly used estimator of the [[population mean]]. There are [[point estimator|point]] and [[interval estimator]]s. The [[point estimator]]s 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= '''[[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 [[linear elasticity|linear theory of elasticity]] which provides a means of calculating the load-carrying and [[Deflection (engineering)|deflection]] characteristics of [[Beam (structure)|beams]]. It covers the case for small deflections of a [[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 [[Ferris wheel]] in the late 19th century. Following these successful demonstrations, it quickly became a cornerstone of engineering and an enabler of the [[Second Industrial Revolution]]. Additional [[mathematical models]] have been developed such as [[plate theory]], but the simplicity of beam theory makes it an important tool in the sciences, especially [[structural engineering|structural]] and [[mechanical engineering]].}}
{{term|term= '''[[Exothermic process]]'''}}{{defn|defn=In [[thermodynamics]], the term exothermic process (exo- : "outside") describes a process or reaction that releases [[energy]] from the system to its surroundings, usually in the form of [[heat]], but also in a form of [[light]] (e.g. a spark, flame, or flash), [[electricity]] (e.g. a battery), or [[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}}
{{Glossary of engineering ToC}}

==F==
{{glossary}}
{{term|term= '''[[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 [[capacitance]], the ability of a body to store an electrical charge. It is named after the English physicist [[Michael Faraday]].}} 
{{term|term= '''[[Faraday constant]]'''}}{{defn|defn=Denoted by the symbol {{math|''F''}} and sometimes stylized as ℱ, is named after [[Michael Faraday]]. In [[physics]] and [[chemistry]], this constant represents the magnitude of [[electric charge]] per [[mole (unit)|mole]] of [[electron]]s.<ref>The term "magnitude" is used in the sense of "[[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 [[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 [[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 [[optics]], Fermat's principle, or the ''principle of least time'', named after French mathematician [[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
|publisher = McGraw-Hill Education
|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= '''[[Fick's laws of diffusion]]'''}}{{defn|defn= Describe [[diffusion]] and were derived by [[Adolf Fick]] in 1855. They can be used to solve for the [[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]].}}
{{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]], [[heat transfer]], [[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]]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]] 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]]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 = 978-0-495-66825-1
}}</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]] to approximate a solution by minimizing an associated error function.}}
{{term|term= '''[[For Inspiration and Recognition of Science and Technology|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= '''[[Nuclear fission|Fission]]'''}}{{defn|defn=In [[nuclear physics]] and [[nuclear chemistry]], nuclear fission is a [[nuclear reaction]] or a [[radioactive decay]] process in which the [[atomic nucleus|nucleus]] of an [[atom]] splits into two or more smaller, lighter [[atomic nucleus|nuclei]]. The fission process often produces  [[gamma ray|gamma]] [[photon]]s, and releases a very large amount of [[energy]] even by the energetic standards of [[radioactive decay]].}} 
{{term|term= '''[[Flow velocity]]'''}}{{defn|defn=In [[continuum mechanics]] the flow velocity in [[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=978-0-471-04492-5|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=978-0-521-73317-5|chapter=Chapter 10:A self-consistent two-fluid model|page=225}}</ref> in [[statistical mechanics]], or drift velocity in [[electromagnetism]], is a [[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., [[law of the wall]]).}}
{{term|term= '''[[Fluid]]'''}}{{defn|defn=In [[physics]], a fluid is a substance that continually [[Deformation (mechanics)|deforms]] (flows) under an applied [[shear stress]], or external force. Fluids are a [[Phase (matter)|phase]] of [[matter]] and include [[liquid]]s, [[gas]]es and [[Plasma (physics)|plasmas]]<!--, and to some extent, [[plasticity (physics)|plastic solids]]  <<  To some extent? To what extent? Solids should be the opposite of fluids in any regard.-->. They are [[Matter|substances]] with zero [[shear modulus]], or, in simpler terms, substances which cannot resist any [[shear force]] applied to them.}} 
{{term|term= '''[[Fluid dynamics]]'''}}{{defn|defn=In [[physics]] and [[engineering]], fluid dynamics  is a subdiscipline of [[fluid mechanics]] that describes the flow of [[fluid]]s—[[liquid]]s and [[gas]]es. It has several subdisciplines, including [[aerodynamics]] (the study of air and other gases in motion) and hydrodynamics (the study of liquids in motion).}} 
{{term|term= '''[[Fluid mechanics]]'''}}{{defn|defn=Is the branch of [[physics]] concerned with the mechanics of [[fluid]]s ([[liquid]]s, [[gas]]es, and [[plasma (physics)|plasma]]s) and the [[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 [[mechanical engineering|mechanical]], [[civil engineering|civil]], [[chemical engineering|chemical]] and [[biomedical engineering]], [[geophysics]], [[oceanography]], [[meteorology]], [[astrophysics]], and [[biology]].}}
{{term|term= '''[[Fluid statics]]'''}}{{defn|defn=Fluid statics, or ''hydrostatics'', is the branch of [[fluid mechanics]] that studies "[[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 [[angular momentum]] so as to efficiently store [[rotational energy]]; a form of kinetic energy proportional to the product of its [[moment of inertia]] and the square of its [[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]] revolving about some fixed axis) then the stored (rotational) energy is directly associated with the square of its rotational speed.}}
{{term|term= '''[[Focus (optics)|Focus]]'''}}{{defn|defn=In [[geometrical optics]], a focus, also called an ''image point'', is the point where [[ray (optics)|light rays]] originating from a point on the object [[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 [[circle of confusion|blur circle]]. This non-ideal focusing may be caused by [[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 [[diffraction]] from the optical system's [[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=978-0-13-501858-3 |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 = 978-0-07-352928-8|language = en|url-access = subscription|access-date = 2021-01-04|archive-date = 2018-08-27|archive-url = https://web.archive.org/web/20180827142501/https://www.mheducation.com/highered/product/shigley-s-mechanical-engineering-design-budynas-nisbett/M0073398209.html}}</ref>) is a unit of [[Mechanical work|work]] or [[energy]] in the [[English Engineering Units|engineering]] and [[Foot–pound–second system#force|gravitational]] systems in [[United States customary units|United States customary]] and [[Imperial units|imperial]] units of measure. It is the energy transferred upon applying a [[force]] of one [[pound-force]] (lbf) through a linear [[displacement (vector)|displacement]] of one [[foot (unit)|foot]]. The corresponding [[SI]] unit is the [[joule]].}}
{{term|term= '''[[Fracture toughness]]'''}}{{defn|defn=In [[materials science]], fracture toughness is the critical [[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 [[plane stress]] conditions and thick components having [[plane strain]] conditions. Plane strain conditions give the lowest fracture toughness value which is a [[material properties|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= '''[[Fraunhofer lines]]'''}}{{defn|defn=In [[physics]] and [[optics]], the Fraunhofer lines are a set of [[spectral line|spectral absorption lines]] named after the German physicist [[Joseph von Fraunhofer]] (1787–1826). The lines were originally observed as dark features ([[absorption line]]s) in the [[optical spectrum]] of the [[Sun]].}}
{{term|term= '''[[Free fall]]'''}}{{defn|defn=In [[Classical mechanics|Newtonian physics]], free fall is any motion of a [[physical body|body]] where [[gravity]] is the only [[force]] acting upon it. In the context of [[general relativity]], where gravitation is reduced to a [[space-time curvature]], a body in free fall has no force acting on it.}}
{{term|term= '''[[Frequency modulation]]'''}}{{defn|defn=Frequency modulation (FM) is the encoding of [[information]] in a [[carrier wave]] by varying the [[instantaneous frequency]] of the wave. The technology is used in [[telecommunications]], [[radio broadcasting]], [[signal processing]], and [[Run-length limited#FM: .280.2C1.29 RLL|computing]].}}
{{term|term= '''[[Freezing point]]'''}}{{defn|defn=The ''melting point'' (or, rarely, ''liquefaction point'') of a substance is the [[temperature]] at which it changes [[state of matter|state]] from [[solid]] to [[liquid]]. At the melting point the solid and liquid phase exist in [[Thermodynamic equilibrium|equilibrium]]. The melting point of a substance depends on [[pressure]] and is usually specified at a [[Standard conditions for temperature and pressure|standard pressure]] such as 1 [[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 [[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 measurements|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= '''[[Friction]]'''}}{{defn|defn=Is the [[force]] resisting the relative motion of solid surfaces, fluid layers, and material elements [[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'' ("[[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
| last1 = Beer | first1 = Ferdinand P. | author-link1 = Ferdinand Beer
| 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 [[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 [[Drag (physics)|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 [[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]] 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]]s to integers, or from the [[real number]]s to real numbers.}}
{{term|term= '''[[Fundamental frequency]]'''}}{{defn|defn=The fundamental frequency, often referred to simply as the ''fundamental'', is defined as the lowest [[frequency]] of a [[Periodic signal|periodic]] [[waveform]]. In music, the fundamental is the musical [[pitch (music)|pitch]] of a note that is perceived as the lowest [[Harmonic series (music)#Partial|partial]] present. In terms of a superposition of [[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 }}</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 |archive-date=2018-08-26 |archive-url=https://web.archive.org/web/20180826153236/http://fourier.eng.hmc.edu/e101/lectures/Fundamental_Frequency.pdf  }}</ref> In other contexts, it is more common to abbreviate it as '''{{var|f}}<sub>1</sub>''', the first [[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  }}</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/  }}</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 }}</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 |archive-date=2020-04-09 |archive-url=https://web.archive.org/web/20200409044223/https://www.open.edu/openlearn/science-maths-technology/engineering-and-technology/technology/creating-musical-sounds/content-section-0  }}</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= '''[[Fundamental interaction]]'''}}{{defn|defn=In [[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 [[gravity|gravitational]] and [[electromagnetism|electromagnetic]] interactions, which produce significant long-range forces whose effects can be seen directly in everyday life, and the [[strong interaction|strong]] and [[weak interaction]]s, which produce forces at [[subatomic scale|minuscule, subatomic distances]] and govern nuclear interactions. Some scientists hypothesize that a [[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 = 978-2-86332-054-9
 }}</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 = 978-3-319-28412-5
 }}</ref>}}
{{term|term= '''[[Fundamental theorem of calculus]]'''}}{{defn|defn=Is a [[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|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 [[engineer]]s must pass in order to be licensed as a [[Professional Engineer]] in the [[United States]]. The second examination is [[Principles and Practice of Engineering Examination]]. The FE [[exam]] is open to anyone with a [[Academic degree|degree]] in engineering or a related field, or currently enrolled in the last year of an [[Accreditation Board for Engineering and Technology|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}}
{{Glossary of engineering ToC}}

==G==
{{glossary}}

{{term|term= '''[[Galvanic cell]]'''}}{{defn|defn=A galvanic cell or voltaic cell, named after [[Luigi Galvani]] or [[Alessandro Volta]], respectively, is an [[electrochemical cell]] that derives electrical energy from spontaneous [[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 [[salt bridge]] or separated by a porous membrane. Volta was the inventor of the [[voltaic pile]], the first [[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 [[electromagnetic radiation]] arising from the [[radioactive decay]] of [[atomic nucleus|atomic nuclei]]. It consists of the shortest wavelength electromagnetic waves and so imparts the highest [[photon energy]].}}
{{term|term= '''[[Gas]]'''}}{{defn|defn=Is one of the [[State of matter|four fundamental states of matter]] (the others being [[solid]], [[liquid]], and [[Plasma (physics)|plasma]]). A pure gas may be made up of individual [[atoms]] (e.g. a [[noble gas]] like [[neon]]), [[chemical element|elemental]] molecules made from one type of atom (e.g. [[oxygen]]), or [[chemical compound|compound]] molecules made from a variety of atoms (e.g. [[carbon dioxide]]). A gas [[mixture]], such as [[Earth's atmosphere|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= '''[[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= '''[[Geiger counter]]'''}}{{defn|defn=Is an instrument used for detecting and measuring [[ionizing radiation]]. Also known as a ''Geiger–Muller counter'' (or ''Geiger–Müller counter''), it is widely used in applications such as radiation [[dosimetry]], [[radiological protection]], [[experimental physics]], and the [[nuclear industry]].}} 
{{term|term= '''[[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 [[Albert Einstein]] in 1915 and is the current description of gravitation in [[modern physics]]. General [[theory of relativity|relativity]] generalizes [[special relativity]] and refines [[Newton's law of universal gravitation]], providing a unified description of gravity as a geometric property of [[space]] and [[time in physics|time]] or [[four-dimensional]] [[spacetime]]. In particular, the ''{{vanchor|[[curvature]] of spacetime|Spacetime curvature|curvature of spacetime}}'' is directly related to the [[energy]] and [[momentum]] of whatever [[matter]] and [[radiation]] are present. The relation is specified by the [[Einstein field equations]], a system of [[partial differential equation]]s.}}
{{term|term= '''[[Geometric mean]]'''}}{{defn|defn=In mathematics, the geometric mean is a [[mean]] or [[average]], which indicates the [[central tendency]] or typical value of a set of numbers by using the product of their values (as opposed to the [[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]], one of the oldest branches of [[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 [[List of geometers|geometer]].}}
{{term|term= '''[[Geophysics]]'''}}{{defn|defn=Is a subject of [[natural science]] concerned with the physical processes and [[Physical property|physical properties]] of the [[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 [[figure of the Earth|shape]]; its [[gravitational]] and [[Earth's magnetic field|magnetic fields]]; its [[structure of the Earth|internal structure]] and [[Earth#Chemical composition|composition]]; its [[geodynamics|dynamics]] and their surface expression in [[plate tectonics]], the generation of [[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 [[water cycle]] including snow and ice; [[geophysical fluid dynamics|fluid dynamics]] of the oceans and the [[atmosphere]]; [[atmospheric electricity|electricity]] and [[magnetism]] in the [[ionosphere]] and [[magnetosphere]] and solar–terrestrial relations; and analogous problems associated with the [[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= '''[[Geotechnical engineering]]'''}}{{defn|defn=Also known as ''geotechnics'', is the branch of [[civil engineering]] concerned with the engineering behavior of [[earth materials]]. It uses the principles and methods of [[soil mechanics]] and [[rock mechanics]] for the solution of [[engineering]] problems and the design of engineering works. It also relies on knowledge of [[geology]], [[hydrology]], [[geophysics]], and other related sciences.}}
{{term|term= '''[[Gluon]]'''}}{{defn|defn=Is an [[elementary particle]] that acts as the exchange particle (or [[gauge boson]]) for the [[strong interaction|strong force]] between [[quark]]s. It is analogous to the exchange of [[photon]]s in the [[electromagnetic force]] between two [[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=[[Georgia State University]], Department of Physics
 |access-date=2012-04-02
}}</ref> In layman's terms, they "glue" quarks together, forming [[hadron]]s such as [[proton]]s and [[neutron]]s.

In technical terms, gluons are [[Vector boson|vector]] [[gauge boson]]s that mediate [[strong interaction]]s of [[quark]]s in [[quantum chromodynamics]] (QCD). Gluons themselves carry the [[color charge]] of the strong interaction. This is unlike the [[photon]], which mediates the [[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 [[quantum electrodynamics]] (QED).}}
{{term|term= '''[[Graham's law]]'''}}{{defn|defn=''Graham's law of effusion'' (also called ''Graham's law of [[diffusion]]'') was formulated by Scottish physical chemist [[Thomas Graham (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 [[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 [[molar mass]] of gas 1
:''M<sub>2</sub>'' is the molar mass of gas 2.}}
{{term|term= '''[[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 [[heat transfer coefficient]] in [[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 [[Einstein tensor]] ''G''<sub>''μν''</sub> vs. the [[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]] [[physical constant]] involved in the calculation of [[gravitational]] effects in [[Sir Isaac Newton]]'s [[Newton's law of universal gravitation|law of universal gravitation]] and in [[Albert Einstein]]'s [[general relativity|general theory of relativity]].}}
{{term|term= '''[[Gravitational energy]]'''}}{{defn|defn=Gravitational energy or ''gravitational potential energy'' is the [[potential energy]] a [[mass]]ive object has in relation to another massive object due to [[gravity]]. It is the potential energy associated with the [[gravitational field]], which is released (converted into [[kinetic energy]]) when the objects [[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 [[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 [[gravity of Earth]], and <math>h</math> is the height of the object's [[center of mass]] above a chosen reference level.<ref name=gpe/>}}
{{term|term= '''[[Gravitational field]]'''}}{{defn|defn=In [[physics]], a gravitational field is a [[scientific model|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 |author-link=Richard Feynman |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=https://feynmanlectures.caltech.edu/I_07.html}}</ref> Thus, a gravitational [[Field (physics)|field]] is used to explain [[Gravity|gravitational]] phenomena, and is measured in [[newton (unit)|newtons]] per [[kilogram]] (N/kg). In its original concept, [[gravity]] was a [[force]] between point [[mass]]es. Following [[Isaac Newton]], [[Pierre-Simon Laplace]] attempted to model gravity as some kind of [[radiation]] field or [[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 [[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=[[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 [[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 [[equivalence principle]].}}
{{term|term= '''[[Gravitational potential]]'''}}{{defn|defn=In [[classical mechanics]], the gravitational potential at a location is equal to the [[Work (physics)|work]] ([[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 [[electric potential]] with [[mass]] playing the role of [[charge (physics)|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 [[wikt:finite|finite]] distance.

In mathematics, the gravitational potential is also known as the [[Newtonian potential]] and is fundamental in the study of [[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= '''[[Gravitational wave]]'''}}{{defn|defn=Gravitational waves are disturbances in the curvature of [[spacetime]], generated by accelerated masses, that [[Wave propagation|propagate as waves]] outward from their source at the [[speed of light]]. They were proposed by [[Henri Poincaré]] in 1905<ref>{{Cite web |title=Sur la dynamique de l'électron - Note de Henri Poincaré publiée dans les Comptes rendus de l'Académie des sciences de la séance du 5 juin 1905 - Membres de l'Académie des sciences depuis sa création |trans-title=On the dynamics of the electron - Note by Henri Poincaré published in the Reports of the Academy of Sciences of the session of June 5, 1905 - Members of the Academy of Sciences since its creation |url=https://www.academie-sciences.fr/pdf/dossiers/Poincare/Poincare_pdf/Poincare_CR1905.pdf |access-date=3 November 2023 |website=www.academie-sciences.fr |language=fr}}</ref> and subsequently [[#History|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=[[Prussian Academy of Sciences|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  }}</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  }}</ref> by [[Albert Einstein]] on the basis of his [[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 [[radiant energy]] similar to [[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 |author2-link=Nathan Rosen |volume=223 |issue=1 |pages=43–54 |doi=10.1016/S0016-0032(37)90583-0 |bibcode=1937FrInJ.223...43E }}</ref> [[Newton's law of universal gravitation]], part of [[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= '''[[Gravity]]'''}}{{defn|defn= Or ''gravitation'', is a [[list of natural phenomena|natural phenomenon]] by which all things with [[mass]] or [[energy]]—including [[planet]]s, [[star]]s, [[galaxy|galaxies]], and even [[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 = 978-1-4292-3042-1
 | bibcode = 2009dufs.book.....C
 }}</ref>—are brought toward (or ''gravitate'' toward) one another. On [[Earth]], gravity gives [[weight]] to [[physical body|physical objects]], and the [[Moon]]'s [[gravitation of the Moon|gravity]] causes the ocean [[tide]]s. The gravitational attraction of the original gaseous matter present in the [[Universe]] caused it to begin [[coalescence (physics)|coalescing]] and [[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= '''[[Ground state]]'''}}{{defn|defn=The ground state of a [[quantum mechanics|quantum-mechanical]] system is its lowest-[[energy]] [[stationary state|state]]; the energy of the ground state is known as the [[zero-point energy]] of the system. An [[excited state]] is any state with energy greater than the ground state. In [[quantum field theory]], the ground state is usually called the [[vacuum state]] or the [[vacuum#The quantum-mechanical vacuum|vacuum]].}}

{{Glossary of engineering ToC}}
{{glossary end}}

==H==
{{glossary}}

{{term|term= '''[[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= '''[[Haptic technology|Haptic]]'''}}{{defn|defn=Tactile feedback technology using the operator's sense of touch. Also sometimes applied to robot [[#Manipulator|manipulator]]s with their own touch sensitivity.}} 
{{term|term= '''[[Hardness]]'''}}{{defn|defn=Is a measure of the resistance to localized [[plastic deformation]] induced by either mechanical [[indentation hardness|indentation]] or [[abrasion (mechanical)|abrasion]]. Some materials (e.g. [[metal]]s) are harder than others (e.g. [[plastic]]s, [[wood]]). Macroscopic hardness is generally characterized by strong [[intermolecular bond]]s, 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 [[ductility]], [[Elasticity (physics)|elastic]] [[stiffness]], [[plasticity (physics)|plasticity]], [[deformation (mechanics)|strain]], [[Strength of materials|strength]], [[toughness]], [[viscoelasticity]], and [[viscosity]].}}
{{term|term= '''[[Harmonic mean]]'''}}{{defn|defn=In [[mathematics]], the harmonic mean (sometimes called the subcontrary mean) is one of several kinds of [[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]] 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= '''[[Heat]]'''}}{{defn|defn=In [[thermodynamics]], heat is [[energy]] in transfer to or from a thermodynamic system, by mechanisms other than [[Work (thermodynamics)|thermodynamic work]] or [[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.com/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>[[Max Born|Born, M.]] (1949), p. 31.</ref><ref>[[Brian Pippard|Pippard, A.B.]] (1957/1966), p. 16.</ref><ref>[[Lev Landau|Landau, L.]], [[Evgeny Lifshitz|Lifshitz, E.M.]] (1958/1969), p. 43</ref><ref>[[Herbert Callen|Callen, H.B.]] (1960/1985), pp. 18–19.</ref><ref>Bailyn, M. (1994), p. 82.</ref>}}
{{term|term= '''[[Heat transfer]]'''}}{{defn|defn=Is a discipline of [[thermal engineering]] that concerns the generation, use, conversion, and exchange of [[thermal energy]] ([[heat]]) between physical systems. Heat transfer is classified into various mechanisms, such as [[thermal conduction]], [[Convection (heat transfer)|thermal convection]], [[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= '''[[Helmholtz free energy]]'''}}{{defn|defn=In [[thermodynamics]], the Helmholtz free energy (or Helmholtz energy) is a [[thermodynamic potential]] that measures the useful [[work (thermodynamics)|work]] obtainable from a [[closed system|closed]] [[thermodynamic system]] at a constant [[temperature]] and [[volume]] ([[Isothermal process|isothermal]], [[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]] and [[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 [[pH]] of a [[buffer solution]]. The numerical value of the [[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 [[acetic acid]] and [[sodium acetate]].}}
{{term|term= '''[[Henry's law]]'''}}{{defn|defn=In physical [[chemistry]], Henry's law is a [[Gas laws|gas law]] that states that the amount of dissolved gas in a liquid is proportional to its [[partial pressure]] above the liquid. The proportionality factor is called Henry's law constant. It was formulated by the English chemist [[William Henry (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 actuator|linear actuator]]s. Often used in [[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 [[Hexapoda|insect-like]] locomotion.}} 
{{term|term= '''[[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 [[rope]] as its lifting medium. The most familiar form is an [[elevator]], the car of which is raised and lowered by a hoist mechanism. Most hoists couple to their loads using a [[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= '''[[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= '''[[Huygens–Fresnel principle]]'''}}{{defn|defn=The Huygens–Fresnel principle (named after [[Netherlands|Dutch]] [[physicist]] [[Christiaan Huygens]] and [[France|French]] physicist [[Augustin-Jean Fresnel]]) is a method of analysis applied to problems of [[wave propagation]] both in the [[Far-field diffraction pattern|far-field limit]] and in near-field [[diffraction]] and also [[Reflection (physics)|reflection]]. It states that every point on a [[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= '''[[Hydraulics]]'''}}{{defn|defn=The study of fluid flow, or the generation of mechanical force and movement by liquid under pressure.}} 
{{term|term= '''[[Hydrocarbon]]'''}}{{defn|defn=A compound containing hydrogen and carbon atoms only; petroleum is made of hydrocarbons.}}

{{Glossary of engineering ToC}}
{{glossary end}}

==I==
{{glossary}}

{{term|term= '''[[Ice point]]'''}}{{defn|defn=The [[freezing point]] of pure [[water]] at one [[atmosphere]]; 0°C (32°F).<ref>[https://en.wiktionary.org/wiki/ice_point Wiktionary]</ref>}}
{{term|term= '''[[Ideal gas]]'''}}{{defn|defn=A model for gases that ignores intermolecular forces. Most gases are approximately ideal at some high temperature and low pressure. }} 
{{term|term= '''[[Ideal gas constant]]'''}}{{defn|defn=The constant in the gas law that relates pressure, volume and temperature.}} 
{{term|term= '''[[Ideal gas law]]'''}}{{defn|defn=Also called the general gas equation, is the [[equation of state]] of a hypothetical [[ideal gas]]. It is a good approximation of the behavior of many [[gas]]es under many conditions, although it has several limitations. It was first stated by [[Benoît Paul Émile Clapeyron]] in 1834 as a combination of the empirical [[Boyle's law]], [[Charles's law]], [[Avogadro's law]], and [[Gay-Lussac's law]].<ref>
{{Cite journal
 | author = Clapeyron, E. | author-link = Benoît Paul Émile Clapeyron
 | 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 [[pressure]], [[volume]] and [[Thermodynamic temperature|temperature]]; <math>n</math> is the [[amount of substance]]; and <math>R</math> is the [[ideal gas constant]]. It is the same for all gases.
It can also be derived from the microscopic [[kinetic theory of gases|kinetic theory]], as was achieved (apparently independently) by [[August Krönig]] in 1856<ref>
{{Cite journal
 | author = Krönig, A. | author-link = August Krönig
 | year = 1856
 | title = Grundzüge einer Theorie der Gase
 | journal = [[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 [[Rudolf Clausius]] in 1857.<ref>
{{Cite journal
 | author = Clausius, R. | author-link = Rudolf Clausius
 | 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]], 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 name=":2">{{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 name=":2"/> Identities are sometimes indicated by the [[triple bar]] symbol {{math|≡}} instead of {{math|1==}}, the [[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= '''[[Electrical impedance|Impedance (electrical)]]'''}}{{defn|defn=In [[electrical engineering]], electrical impedance is the measure of the opposition that a [[electrical circuit|circuit]] presents to a [[electric current|current]] when a [[voltage]] is applied.}}
{{term|term= '''[[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 [[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]] is a given function; an [[antiderivative]].<ref>https://en.wiktionary.org/wiki/indefinite_integral Wiktionary</ref>}}{{term|term= '''[[Inductance]]'''}}{{defn|defn=In [[electromagnetism]] and [[electronics]], inductance is the tendency of an [[electrical conductor]] to oppose a change in the [[electric current]] flowing through it. The flow of electric current creates a [[magnetic field]] around the conductor. The field strength depends on the magnitude of the current, and follows any changes in current. From [[Faraday's law of induction]], any change in magnetic field through a circuit induces an [[electromotive force]] (EMF) ([[voltage]]) in the conductors, a process known as [[electromagnetic induction]]. This induced voltage created by the changing current has the effect of opposing the change in current. This is stated by [[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=978-0-17-035552-0 |page=901 |edition=2ndition |chapter=32 |date=2016-10-01 |publisher=Cengage AU |df=dmy-all}}</ref> An [[electronic component]] designed to add inductance to a circuit is called an [[inductor]]. It typically consists of a [[electromagnetic coil|coil]] or helix of wire.}}
{{term|term= '''[[Inductor]]'''}}{{defn|defn=An inductor, also called a coil, choke, or reactor, is a [[incremental passivity|passive]] two-terminal [[electronic component|electrical component]] that stores energy in a [[magnetic field]] when [[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 [[Electromagnetic coil|coil]].}}
{{term|term= '''[[Industrial engineering]]'''}}{{defn|defn=Is an engineering profession that is concerned with the optimization of complex [[process (engineering)|processes]], [[system]]s, or [[organizations]] by developing, improving and implementing integrated systems of people, money, knowledge, information and equipment. Industrial engineers use specialized [[knowledge]] and [[skills]] in the mathematical, physical and [[social sciences]], together with the [[principles]] and methods of [[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 [[Wage labour|labour]], [[materials]] and [[machines]] and also improve the [[quality (business)|quality]] and [[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= '''[[Inertia]]'''}}{{defn|defn=Is the resistance of any physical [[physical body|object]] to any change in its [[velocity]]. This includes changes to the object's [[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 [[force]]s act upon them.}}
{{term|term= '''[[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 [[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]], an integral assigns numbers to functions in a way that describes displacement, area, volume, and other concepts that arise by combining [[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]] 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]], an integral transform maps a [[function (mathematics)|function]] from its original [[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 [[French language|French]] ''{{lang|fr|Système international (d'unités)}}'') is the modern form of the [[metric system]]. It is the only [[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]] (the unit of [[time]] with the symbol s), [[metre]] ([[length]], m), [[kilogram]] ([[mass]], kg), [[ampere]] ([[electric current]], A), [[kelvin]] ([[thermodynamic temperature]], K), [[Mole (unit)|mole]] ([[amount of substance]], mol), and [[candela]] ([[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 [[velocity]] is the metre per second, m⋅s<sup>−1</sup>; of [[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 [[force]], equivalent to kg⋅m⋅s<sup>−2</sup>; the [[joule]] (J), the unit of [[energy]], equivalent to kg⋅m<sup>2</sup>⋅s<sup>−2</sup>, etc. The most recently named derived unit, the [[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 [[Electric field|electric field strength]] is the volt per metre, V/m, where the [[volt]] is the derived unit for [[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]] progresses and the precision of measurements improves.}}
{{term|term= '''[[Interval estimation]]'''}}{{defn|defn=In [[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]], which gives a single value. [[Jerzy Neyman]] (1937) identified interval estimation ("estimation by interval") as distinct from [[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]] indicated that interval estimation was actually the problem [[statisticians]] really had in mind.}}
{{term|term= '''[[Inorganic chemistry]]'''}}{{defn|defn=Deals with [[chemical synthesis|synthesis]] and behavior of [[inorganic compound|inorganic]] and [[organometallic chemistry|organometallic]] compounds. This field covers [[chemical compound]]s that are not carbon-based, which are the subjects of [[organic chemistry]]. The distinction between the two disciplines is far from absolute, as there is much overlap in the subdiscipline of [[organometallic chemistry]]. It has applications in every aspect of the chemical industry, including [[catalysis]], [[materials science]], [[pigment]]s, [[surfactant]]s, [[coating]]s, [[pharmaceutical drug|medications]], [[fuel]]s, and [[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  | 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= '''[[Ion]]'''}}{{defn|defn=Is a [[particle]], [[atom]] or [[molecule]] with a net [[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 [[electron]]s being unequal to its total number of [[proton]]s.}}
{{term|term= '''[[Ionic bonding]]'''}}{{defn|defn=Is a type of [[chemical bond]]ing that involves the [[Coulomb's law|electrostatic attraction]] between oppositely charged [[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 [[ionic compound]]s. It is one of the main types of bonding along with [[covalent bond]]ing and [[metallic bonding]]. Ions are atoms (or groups of atoms) with an electrostatic charge. Atoms that gain electrons make negatively charged ions (called [[anion]]s). Atoms that lose electrons make positively charged ions (called [[cations]]). This transfer of electrons is known as ''electrovalence'' in contrast to [[covalent bond|covalence]]. In the simplest case, the cation is a [[metal]] atom and the anion is a [[Nonmetal (chemistry)|nonmetal]] atom, but these ions can be of a more complex nature, e.g. [[polyatomic ions|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 [[metal]] to a [[non-metal]] in order to obtain a full valence shell for both atoms.}}
{{term|term= '''[[Ionization]]'''}}{{defn|defn=Ionization or ''ionisation'' is the process by which an [[atom]] or a [[molecule]] acquires a negative or positive [[Electric charge|charge]] by gaining or losing [[electron]]s, often in conjunction with other chemical changes. The resulting electrically charged atom or molecule is called an [[ion]]. Ionization can result from the loss of an electron after collisions with [[subatomic particle]]s, collisions with other atoms, molecules and ions, or through the interaction with [[electromagnetic radiation]]. [[Heterolytic bond cleavage]] and heterolytic [[substitution reaction]]s can result in the formation of ion pairs. Ionization can occur through radioactive decay by the [[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= '''[[Isotope]]'''}}{{defn|defn=Isotopes are variants of a particular [[chemical element]] which differ in [[neutron number]], and consequently in [[nucleon number]]. All isotopes of a given element have the same number of [[proton]]s but different numbers of [[neutrons]] in each [[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 of engineering ToC}}
{{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=978-0-444-51110-2 |via=Google Books |access-date=25 September 2014|last1=Kapusta |first1=J. |last2=Müller |first2=B. |last3=Rafelski |first3=J. |date=9 December 2003 |publisher=Gulf Professional }}{{full citation needed|date=May 2020}}{{dead link|date=May 2020}}</ref> is a [[subatomic particle]], a [[flavour (particle physics)|flavor]]-neutral [[meson]] consisting of a [[charm quark]] and a charm [[antiparticle|antiquark]].  Mesons formed by a [[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 [[Spin (physics)|spin]] of 1 and its low [[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 release
 |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 [[energy]] in the [[International System of Units]].<ref>{{SIbrochure8th|page=120}}</ref> It is equal to the energy transferred to (or [[work (physics)|work]] done on) an object when a [[force]] of one [[Newton (unit)|newton]] acts on that object in the direction of the object's motion through a distance of one [[metre]] (1 newton-metre or N⋅m). It is also the energy dissipated as heat when an electric [[current (electricity)|current]] of one [[ampere]] passes through a [[Electrical resistance and conductance|resistance]] of one [[ohm]] for one second. It is named after the English physicist [[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>}}

{{term|term= '''[[Joule heating]]'''}}{{defn|defn=Also known as resistive, resistance, or Ohmic heating, is the process by which the passage of an [[electric current]] through a [[conductor (material)|conductor]] produces [[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]] [[thermodynamic temperature]] [[Scale of temperature|scale]] using as its null point [[absolute zero]], the temperature at which all [[Kinetic theory of gases|thermal motion]] ceases in the classical description of [[thermodynamics]]. The kelvin (symbol: K) is the [[SI base unit|base unit]] of [[temperature]] in the [[International System of Units]] (SI).}} 
{{term|term= '''[[Kelvin–Planck statement]]'''}}{{defn|defn=(Or the ''Heat Engine Statement''), of the [[second law of thermodynamics]] states that ''it is impossible to devise a [[thermodynamic cycle|cyclically]] operating heat engine, the effect of which is to absorb [[energy]] in the form of heat from a single [[heat reservoir|thermal reservoir]] and to deliver an equivalent amount of [[Work (physics)|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 [[heat engine]] that has 100% [[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= '''[[Kinematics]]'''}}{{defn|defn=Is a branch of [[classical mechanics]] that describes the [[Motion (physics)|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 |author-link=E. T. 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= '''[[Laminar flow]]'''}}{{defn|defn=In [[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 card]]s. 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
 
 |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 [[momentum diffusion]] and low momentum [[convection]].}}
{{term|term= '''[[Laplace transform]]'''}}{{defn|defn=In [[mathematics]], the Laplace transform, named after its inventor [[Pierre-Simon Laplace]] ({{IPAc-en|l|ə|ˈ|p|l|ɑ:|s}}), is an [[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]]s. In particular, it transforms differential equations into algebraic equations and [[convolution]] into multiplication.<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= '''[[LC circuit]]'''}}{{defn|defn=A circuit consisting entirely of inductors (L) and capacitors (C).}} 
{{term|term= '''[[Le Chatelier's principle]]'''}}{{defn|defn=Le Chatelier's principle, also called ''Chatelier's principle'', is a principle of [[chemistry]] used to predict the effect of a change in conditions on [[chemical equilibrium|chemical equilibria]]. The principle is named after French chemist [[Henry Louis Le Chatelier]], and sometimes also credited to [[Karl Ferdinand Braun]], who discovered it independently. It can be stated as:

{{blockquote|When any system at equilibrium for a long period of time is subjected to a change in [[concentration]], [[temperature]], [[volume]], or [[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 [[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

{{blockquote|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"/>

{{blockquote|Any change in [[status quo]] prompts an opposing reaction in the responding system.}}}}
{{term|term= '''[[Lenz's law]]'''}}{{defn|defn=Lenz's law, named after the physicist [[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 [[electric current]] which is [[Electromagnetic induction|induced]] in a [[Electrical conductor|conductor]] by a changing [[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 [[electromagnetism]], such as the direction of voltage induced in an [[inductor]] or [[Electromagnetic coil|wire loop]] by a changing current, or the drag force of [[eddy current]]s exerted on moving objects in a magnetic field.

Lenz's law may be seen as analogous to [[Newton's laws of motion#Newton's third law|Newton's third law]] in [[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= '''[[Lepton]]'''}}{{defn|defn=In [[particle physics]], a lepton is an [[elementary particle]] of [[half-integer spin]] ([[Spin (physics)|spin]] {{Frac|1|2}}) that does not undergo [[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: [[electric charge|charged]] leptons (also known as the [[electron]]-like leptons), and neutral leptons (better known as [[neutrino]]s). Charged leptons can combine with other particles to form various [[composite particle]]s such as [[atom]]s and [[positronium]], while neutrinos rarely interact with anything, and are consequently rarely observed. The best known of all leptons is the [[electron]].}}
{{term|term= '''[[Lever]]'''}}{{defn|defn=Is a [[simple machine]] consisting of a [[beam (structure)|beam]] or rigid rod pivoted at a fixed [[hinge]], or ''[[:wikt:fulcrum|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 [[Lever#Classes of levers|three types]]. Also, [[Leverage (mechanics)|leverage]] is mechanical advantage gained in a system. It is one of the six [[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 [[mechanical advantage]] of the lever. As such, the lever is a [[mechanical advantage device]], trading off force against movement.}}
{{term|term= '''[[L'Hôpital's rule]]'''}}{{defn|defn=In [[mathematics]], more specifically [[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]]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 [[France|French]] [[mathematician]] [[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 [[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= '''[[Light]]'''}}{{defn|defn=Light or ''visible light'' is [[electromagnetic radiation]] within the portion of the [[electromagnetic spectrum]] that can be [[visual perception|perceived]] by the [[human eye]].<ref>[[International Commission on Illumination|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]]s in the range of 400–700 [[Nanometre|nm]], between the [[infrared]] (with longer wavelengths) and the [[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 [[frequency]] range of roughly 430–750 [[Terahertz (unit)|terahertz]] (THz).}}
{{term|term= '''[[Linear actuator]]'''}}{{defn|defn=Is an [[actuator]] that creates motion in a straight line, in contrast to the circular motion of a conventional [[electric motor]]. Linear actuators are used in machine tools and industrial machinery, in computer [[peripheral]]s such as disk drives and printers, in [[valve]]s and [[Damper (flow)|dampers]], and in many other places where linear  motion is required. [[Hydraulics|Hydraulic]] or [[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= '''[[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 [[Finite strain theory|nonlinear theory of elasticity]] and a branch of [[continuum mechanics]].}}
{{term|term= '''[[Liquid]]'''}}{{defn|defn=A liquid is a nearly [[Compressibility|incompressible]] [[fluid]] that conforms to the shape of its container but retains a (nearly) constant volume independent of pressure. As such, it is one of [[State of matter#Four fundamental states|the four fundamental states of matter]] (the others being [[solid]], [[gas]], and [[Plasma (physics)|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 [[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 [[surface tension]], leading to [[wetting]] phenomena. [[Water]] is, by far, the most common liquid on Earth.}}
{{term|term= '''[[Logarithm]]'''}}{{defn|defn=In [[mathematics]], the logarithm is the [[inverse function]] to [[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> ''x''}}, or even without the explicit base, {{math|log ''x''}}, when no confusion is possible, or when the base does not matter such as in [[big O notation]].

More generally, exponentiation allows any positive [[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> 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]] and is commonly used in science and engineering. The [[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]], because of its simpler [[integral]] and [[derivative]]. The [[binary logarithm]] uses base {{math|2}} (that is {{math|1=''b'' = 2}}) and is frequently used in [[computer science]]. Logarithms are examples of [[concave function]]s.}}
{{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= '''[[Logarithmic mean temperature difference]]'''}}{{defn|defn=(Also known as log mean temperature difference, LMTD) is used to determine the temperature driving force for [[heat transfer]] in flow systems, most notably in [[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= '''[[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 [[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 [[electrical resistance]] as well.}}
{{term|term= '''[[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 [[Topology (electrical circuits)|topology]] consisting of discrete entities that approximate the behaviour of the distributed system under certain assumptions. It is useful in [[electrical network|electrical systems]] (including [[electronics]]), mechanical [[multibody system]]s, [[heat transfer]], [[acoustics]], etc. Mathematically speaking, the simplification reduces the [[State space (controls)|state space]] of the system to a [[counting number|finite]] [[dimension]], and the [[partial differential equation]]s (PDEs) of the continuous (infinite-dimensional) time and space model of the physical system into [[ordinary differential equation]]s (ODEs) with a finite number of parameters.}}
{{glossary end}}
{{Glossary of engineering ToC}}

==M–Z==
{{Further|Glossary of engineering: M–Z}}

== See also ==
{{colbegin}}
*[[Engineering]]
*[[National Council of Examiners for Engineering and Surveying]]
*[[Fundamentals of Engineering Examination]]
*[[Principles and Practice of Engineering Examination]]
*[[Graduate Aptitude Test in Engineering]]
*[[Glossary of aerospace engineering]]
*[[Glossary of civil engineering]]
*[[Glossary of electrical and electronics engineering]]
*[[Glossary of mechanical engineering]]
*[[Glossary of structural engineering]]
*[[Glossary of architecture]]
*[[Glossary of areas of mathematics]]
*[[Glossary of artificial intelligence]]
*[[Glossary of astronomy]]
*[[Glossary of biology]]
*[[Glossary of calculus]]
*[[Glossary of chemistry terms|Glossary of chemistry]]
*[[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}}

===Works cited===
* {{Citation|last1=Anton|first1=Howard|last2=Bivens|first2=Irl C.|last3=Davis|first3=Stephen|title=Calculus: Early Transcendentals|year=2016|edition=11th|publisher=John Wiley & Sons|isbn=978-1-118-88382-2}} 
* {{Citation|last=Apostol|first=Tom M.|title=Calculus, Vol.&nbsp;1: One-Variable Calculus with an Introduction to Linear Algebra|url=https://archive.org/details/calculus01apos|year=1967|edition=2nd|publisher=Wiley|isbn=978-0-471-00005-1|author-link=Tom M. Apostol}}
*{{cite web
|author=American Geophysical Union
|url=http://about.agu.org/our-science/
|title=Our Science
|work=About AGU
|year=2011
|access-date=30 September 2011
|ref={{harvid|AGU|2011}}
|author-link=American Geophysical Union
}}
*{{cite book|last=Downing|first=Douglas|title=Algebra the Easy Way|url=https://books.google.com/books?id=RiX-TJLiQv0C|year=2003|publisher=Barrons Educational Series|isbn=978-0-7641-1972-9}}
* {{cite book |last=Halmos |first=Paul R. |author-link=Paul Halmos |year=1970 |title=Naive Set Theory |publisher=Springer-Verlag |isbn=978-0-387-90092-6 |url=https://books.google.com/books?id=x6cZBQ9qtgoC}}
*{{cite web
|title=About IUGG
|url=http://www.iugg.org/about/
|year=2011
|access-date=30 September 2011
|ref={{harvid|IUGG|2011}}
}}
*{{cite book|last1=Kate|first1=S.K.|last2=Bhapkar|first2=H.R.|title=Basics Of Mathematics|url=https://books.google.com/books?id=v4R0GSJtEQ4C|year=2009|publisher=Technical Publications|isbn=978-81-8431-755-8}}{{Dead link|date=September 2023 |bot=InternetArchiveBot |fix-attempted=yes }}
* {{cite arXiv
| last1=Legg |first1=Shane |last2=Hutter |first2=Marcus |date=15 June 2007
| title=A Collection of Definitions of Intelligence
|class=cs.AI |eprint=0706.3639
}}
* {{cite book|last=Nilsson|first=Nils|author-link=Nils Nilsson (researcher)|year=1998|title=Artificial Intelligence: A New Synthesis|url=https://archive.org/details/artificialintell0000nils|url-access=registration|publisher=Morgan Kaufmann|isbn=978-1-55860-467-4|access-date=18 November 2019|archive-date=26 July 2020|archive-url=https://web.archive.org/web/20200726131654/https://archive.org/details/artificialintell0000nils|url-status=live}}
* {{cite book|first1=David|last1=Poole|author-link=David Poole (researcher)|first2=Alan|last2=Mackworth|author2-link=Alan Mackworth|first3=Randy|last3=Goebel|author3-link=Randy Goebel|year=1998|title=Computational Intelligence: A Logical Approach|publisher=Oxford University Press|location=New York|isbn=978-0-19-510270-3|url=https://archive.org/details/computationalint00pool|access-date=22 August 2020|archive-date=26 July 2020|archive-url=https://web.archive.org/web/20200726131436/https://archive.org/details/computationalint00pool|url-status=live}}
* {{Russell Norvig 2003}}
* {{Cite book|first1=Stuart J.|last1=Russell|first2=Peter|last2=Norvig|title=[[Artificial Intelligence: A Modern Approach]] <!-- | url = http://aima.cs.berkeley.edu/ -->|year=2009|edition=3rd|publisher=Prentice Hall|location=Upper Saddle River, New Jersey|isbn=978-0-13-604259-4|author-link=Stuart J. Russell|author2-link=Peter Norvig}}.
*{{cite encyclopedia
|last1=Sheriff
|first1=Robert E.
|title=Geophysics
|encyclopedia=Encyclopedic Dictionary of Exploration Geophysics
|edition=3rd
|year=1991
|publisher=Society of Exploration
|isbn=978-1-56080-018-7
|url-access=registration
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}}
*{{cite book|last=Shirali|first=S. |title=Adventures in Problem Solving|url=https://books.google.com/books?id=TPE0fXGnYtMC&pg=PP1|date= 2002|publisher=Universities Press|isbn=978-81-7371-413-9}}

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

{{DEFAULTSORT:Glossary of engineering: A-L}}
[[Category:Engineering]]
[[Category:Engineering disciplines]]
[[Category:Glossaries of science|engineering]]
[[Category:Safety]]
[[Category:Glossaries of technology|Engineering]]
[[Category:Wikipedia glossaries using description lists]]