1. McGraw-HillDictionary ofEngineering Second EditionMcGraw-HillNew York Chicago San Francisco Lisbon London MadridMexico City Milan New Delhi San Juan Seoul Singapore Sydney Toronto

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ContentsPreface ...................................................................................................................vStaff ........................................................................................................................viHow to Use the Dictionary .............................................................................viiFields and Their Scope ....................................................................................ixPronunciation Key .............................................................................................xiA-Z Terms ...................................................................................................... 1-626Appendix .................................................................................................... 627-643Equivalents of commonly used units for the U.S. Customary System and the metric system ......................................629Conversion factors for the U.S. Customary System,metric system, and International System .......................................630Special constants ....................................................................................634Electrical and magnetic units ................................................................635Dimensional formulas of common quantities .....................................635Internal energy and generalized work ...................................................636General rules of integration ...................................................................637Schematic electronic symbols ...............................................................639 4. This page intentionally left blank. 5. PrefaceThe McGraw-Hill Dictionary of Engineering provides a compendium of more than18,000 terms that are central to the various branches of engineering and relatedfields of science. The coverage in this Second Edition is focused on buildingconstruction, chemical engineering, civil engineering, control systems, designengineering, electricity and electronics, engineering acoustics, industrial engi-neering, mechanics and mechanical engineering, systems engineering, andthermodynamics. Many new entries have been added since the previous editionwith others revised as necessary. Many of the terms used in engineering areoften found in specialized dictionaries and glossaries; this Dictionary, however,aims to provide the user with the convenience of a single, comprehensivereference.All of the definitions are drawn from the McGraw-Hill Dictionary of Scientific andTechnical Terms, Sixth Edition (2003). Each definition is classified according tothe field with which it is primarily associated; if it is used in more than onearea, it is idenfified by the general label [ENGINEERING]. The pronunciation ofeach term is provided along with synonyms, acronyms, and abbreviationswhere appropriate. A guide to the use of the Dictionary appears on pages viiand viii, explaining the alphabetical organization of terms, the format of thebook, cross referencing, and how synonyms, variant spellings, abbreviations,and similar information are handled. The Pronunciation Key is given on pagexi. The Appendix provides conversion tables for commonly used scientificunits as well as listings of useful mathematical, engineering, and scientific data.It is the editors hope that the Second Edition of the McGraw-Hill Dictionary ofEngineering will serve the needs of scientists, engineers, students, teachers,librarians, and writers for high-quality information, and that it will contributeto scientific literacy and communication. Mark D. LickerPublisher vCopyright 2003 by The McGraw-Hill Companies, Inc. Click Here for Terms of Use. 6. StaffMark D. Licker, PublisherScienceElizabeth Geller, Managing EditorJonathan Weil, Senior Staff EditorDavid Blumel, Staff EditorAlyssa Rappaport, Staff EditorCharles Wagner, Digital Content ManagerRenee Taylor, Editorial AssistantRoger Kasunic, Vice PresidentEditing, Design, and ProductionJoe Faulk, Editing ManagerFrank Kotowski, Jr., Senior Editing SupervisorRon Lane, Art DirectorThomas G. Kowalczyk, Production ManagerPamela A. Pelton, Senior Production SupervisorHenry F. Beechhold, Pronunciation EditorProfessor Emeritus of EnglishFormer Chairman, Linguistics ProgramThe College of New JerseyTrenton, New JerseyviCopyright 2003 by The McGraw-Hill Companies, Inc. Click Here for Terms of Use. 7. How to Use the DictionaryALPHABETIZATION. The terms in the McGraw-Hill Dictionary of Engineering,Second Edition, are alphabetized on a letter-by-letter basis; word spacing,hyphen, comma, solidus, and apostrophe in a term are ignored in the sequenc-ing. For example, an ordering of terms would be:abat-ventADPA blockair bandAbney levelairblastingFORMAT. The basic format for a defining entry provides the term in boldface,the field is small capitals, and the single definition in lightface:term [FIELD] Definition.A field may be followed by multiple definitions, each introduced by a bold-face number:term [FIELD] 1. Definition. 2. Definition. 3. Definition.A term may have definitions in two or more fields:term [CIV ENG] Definition. [ENG ACOUS] Definition.A simple cross-reference entry appears as:term See another term.A cross reference may also appear in combination with definitions:term [CIV ENG] Definition. [ENG ACOUS] Definition.CROSS REFERENCING. A cross-reference entry directs the user to thedefining entry. For example, the user looking up access flooring finds:access flooring See raised flooring.The user then turns to the R terms for the definition. Cross references arealso made from variant spellings, acronyms, abbreviations, and symbols.ARL See acceptable reliability level.arriswise See arrisways.at See technical atmosphere.ALSO KNOWN AS . . . , etc. A definition may conclude with a mention of asynonym of the term, a variant spelling, an abbreviation for the term, or otherviiCopyright 2003 by The McGraw-Hill Companies, Inc. Click Here for Terms of Use. 8. such information, introduced by Also known as . . . , Also spelled . . . ,Abbreviated . . . , Symbolized . . . , Derived from . . . . When a term hasmore than one definition, the positioning of any of these phrases conveys theextent of applicability. For example:term [CIV ENG] 1. Definition. Also known as synonym. 2. Definition. Symbolized T.In the above arrangement, Also known as . . . applies only to the first defini-tion; Symbolized . . . applies only to the second definition.term [CIV ENG] 1. Definition. 2. Definition. [ENG ACOUS] Definition.Also known as synonym.In the above arrangement, Also known as . . . applies only to the second field.term [CIV ENG] Also known as synonym. 1. Definition. 2. Definition. [ENG ACOUS] Definition.In the above arrangement, Also known as . . . applies to both definitions inthe first field.term Also known as synonym. [CIV ENG] 1. Definition. 2. Definition. [ENG ACOUS] Definition.In the above arrangement, Also known as . . . applies to all definitions inboth fields.viii 9. Fields and Their Scopebuilding constructionThe technology of assembling materials into a struc-ture, especially one designated for occupancy.chemical engineeringA branch of engineering which involves the designand operation of chemical plants.civil engineeringThe planning, design, construction, and maintenance offixed structures and ground facilities for industry, for transportation, for useand control of water, for occupancy, and for harbor facilities.control systemsThe study of those systems in which one or more outputsare forced to change in a desired manner as time progresses.design engineeringThe branch of engineering concerned with the designof a product or facility according to generally accepted uniform standards andprocedures, such as the specification of a linear dimension, or a manufacturingpractice, such as the consistent use of a particular size of screw to fasten covers.electricityThe science of physical phenomena involving electric charges andtheir effects when at rest and when in motion.electronicsThe technological area involving the manipulation of voltagesand electric currents through the use of various devices for the purpose ofperforming some useful action with the currents and voltages; this field isgenerally divided into analog electronics, in which the signals to be manipu-lated take the form of continuous currents or voltages, and digital electronics,in which signals are represented by a finite set of states.engineeringThe science by which the properties of matter and the sourcesof power in nature are made useful to humans in structures, machines, andproducts.engineering acousticsThe field of acoustics that deals with the production,detection, and control of sound by electrical devices, including the study,design, and construction of such things as microphones, loudspeakers, soundrecorders and reproducers, and public address sytems.industrial engineeringA branch of engineering dealing with the design,development, and implementation of integrated systems of humans, machines,and information resources to provide products and services.ixCopyright 2003 by The McGraw-Hill Companies, Inc. Click Here for Terms of Use. 10. mechanical engineeringThe branch of engineering concerned with energyconversion, mechanics, and mechanisms and devices for diverse applications,ranging from automotive parts through nanomachines.mechanicsThe branch of physics which seeks to formulate general rules forpredicting the behavior of a physical system under the influence of any typeof interaction with its environment.systems engineeringThe branch of engineering dealing with the design ofa complex interconnection of many elements (a system) to maximize an agreed-upon measure of system performance.thermodynamicsThe branch of physics which seeks to derive, from a fewbasic postulates, relations between properties of substances, especially thosewhich are affected by changes in temperature, and a description of the conver-sion of energy from one form to another.x 11. Pronunciation KeyVowels Consonantsa as inbat, that b as in bib, dribblea as inbait, crate ch as in charge, stretcha as inbother, fatherd as in dog, bade as inbet, netfas in fix, safee as inbeet, treat g as in good, signalias in bit, skit h as in hand, behindas in bite, light jas in joint, digito as in boat, notekas in cast, bricko as in bought, tautkas in Bach (used rarely)u as inbook, pulllas in loud, bellu as inboot, poolm as in mild, summer as inbut, sofa n as in new, dentau as in crowd, powern indicates nasalization of preced-oi as inboil, spoiling vowely as in formula, spectacular as in ring, single yu as in fuel, mulep as in pier, slip ras in red, scarSemivowels/Semiconsonantssas in sign, postw as in wind, twin sh as in sugar, shoeyas in yet, oniontas in timid, cat th as in thin, breathStress (Accent)th as in then, breatheprecedes syllable with primary vas in veil, weavestress zas in zoo, cruise zh as in beige, treasureprecedes syllable with secondarystress Syllabication Indicates syllable boundary precedes syllable with variable when following syllable isor indeterminate primary/ unstressedsecondary stressxiCopyright 2003 by The McGraw-Hill Companies, Inc. Click Here for Terms of Use. 12. Aa See ampere. reposition it if it drifts out of the acceptableA See ampere; angstrom. range. { bort branch } A See angstrom. Abrams law [CIV ENG] In concrete materials,a axis [MECH ENG] The angle that specifies thefor a mixture of workable consistency therotation of a machine tool about the x axis.strength of concrete is determined by the ratio{ a ak sis } of water to cement. { abrmz lo } abandon [ENG] To stop drilling and remove the abrasion [ENG] 1. The removal of surface mate-drill rig from the site of a borehole before therial from any solid through the frictional actionintended depth or target is reached. { ban of another solid, a liquid, or a gas or combinationdn } thereof. 2. A surface discontinuity broughtabate [ENG] 1. To remove material, for example, about by roughening or scratching. { brain carving stone. 2. In metalwork, to excise or zhn }beat down the surface in order to create a patternabrasion test [MECH ENG] The measurement ofor figure in low relief. { bat } abrasion resistance, usually by the weighing ofabatement [ENG] 1. The waste produced in cut- a material sample before and after subjecting itting a timber, stone, or metal piece to a desired to a known abrasive stress throughout a knownsize and shape. 2. A decrease in the amount time period, or by reflectance or surface finishof a substance or other quantity, such as atmos-comparisons, or by dimensional comparisons.pheric pollution. { batmnt } { brazhn test } abat-jour [BUILD] A device that is used to de-abrasive belt [MECH ENG] A cloth, leather, orflect daylight downward as it streams through a paper band impregnated with grit and rotatedwindow. { aba zhur } as an endless loop to abrade materials throughabattoir [IND ENG] A building in which cattle orcontinuous friction. { brasv belt } other animals are slaughtered. { ab twar } abrasive blasting [MECH ENG] The cleaning orabat-vent [BUILD] A series of sloping boards or finishing of surfaces by the use of an abrasivemetal strips, or some similar contrivance, to entrained in a blast of air. { brasv blasti } break the force of wind without being an obstruc- abrasive cloth [MECH ENG] Tough cloth totion to the passage of air or sound, as in a louver whose surface an abrasive such as sand or emeryor chimney cowl. { a ba van } has been bonded for use in grinding or polishing.ablatograph [ENG] An instrument that records{ brasv kloth } ablation by measuring the distance a snow orabrasive cone [MECH ENG] An abrasive sint-ice surface falls during the observation period.ered or shaped into a solid cone to be rotated{ blad graf } by an arbor for abrasive machining. { brasA block [CIV ENG] A hollow concrete masonry v kon }block with one end closed and the other openabrasive disk [MECH ENG] An abrasive sinteredand with a web between, so that when the blockor shaped into a disk to be rotated by an arboris laid in a wall two cells are produced. { a for abrasive machining. { brasv disk } blak } abrasive jet cleaning [ENG] The removal of dirtAbney level See clinometer. { abne levl } from a solid by a gas or liquid jet carrying abra-abnormal reading See abnormal time. { ab nor sives to ablate the surface. { brasv jetml redi } kleni } abnormal time [IND ENG] During a time study,abrasive machining [MECH ENG] Grinding, dril-an elapsed time for any element which is exces- ling, shaping, or polishing by abrasion.sively longer or shorter than the median of the { brasv m sheni } elapsed times. Also known as abnormal read- abreast milling [MECH ENG] A milling methoding. { ab norml tm } in which parts are placed in a row parallel to theabort branch [CONT SYS] A branching instruc-axis of the cutting tool and are milled simultane-tion in the program controlling a robot thatously. { brest mili }causes a test to be performed on whether theabreuvoir [CIV ENG] A space between stones intool-center point is properly positioned, and tomasonry to be filled with mortar. { abru vwar } Copyright 2003 by The McGraw-Hill Companies, Inc. Click Here for Terms of Use. 13. ABSABS See antilock braking system. and not proceed until there is a change in theabsolute altimeter [ENG] An instrument which signal. Also known as stop and stay. { abemploys radio, sonic, or capacitive technology s lut stap } to produce on its indicator the measurement of absolute temperature [THERMO] 1. The tem-distance from the aircraft to the terrain below. perature measurable in theory on the thermody-Also known as terrain-clearance indicator. namic temperature scale. 2. The temperature{ abs lut al timdr } in Celsius degrees relative to the absolute zeroabsolute altitude [ENG] Altitude above the ac- at 273.16C (the Kelvin scale) or in Fahrenheittual surface, either land or water, of a planet or degrees relative to the absolute zero at natural satellite. { abs lut alttud } 459.69F (the Rankine scale). { abs lutabsolute blocking [CIV ENG] A control arrange- temprchur }ment for rail traffic in which a track is dividedabsolute temperature scale [THERMO] A scaleinto sections or blocks upon which a train may with which temperatures are measured relativenot enter until the preceding train has left.to absolute zero. Also known as absolute scale.{ abs lut blaki } { abs lut temprchur skal } absolute block system [CIV ENG] A block sys- absolute volume [ENG] The total volume of thetem in which only a single railroad train is per-particles in a granular material, including bothmitted within a block section during a given pe- permeable and impermeable voids but excludingriod of time. { abs lut blak sistm } spaces between particles. { abs lut valabsolute efficiency [ENG ACOUS] The ratio of yum }the power output of an electroacoustic trans-absolute weighing [ENG] Determination of theducer, under specified conditions, to the powermass of a sample and expressing its value inoutput of an ideal electroacoustic transducer. units, fractions, and multiples of the mass of the{ abs lut fishnse } prototype of the international kilogram. { ababsolute expansion [THERMO] The true expan-s lut wai } sion of a liquid with temperature, as calculated absolute zero [THERMO] The temperature ofwhen the expansion of the container in which 273.16C, or 459.69F, or 0 K, thought to bethe volume of the liquid is measured is taken into the temperature at which molecular motion van-account; in contrast with apparent expansion.ishes and a body would have no heat energy.{ abs lut ik spanshn } { abs lut ziro }absolute instrument [ENG] An instrumentabsorber [CHEM ENG] Equipment in which awhich measures a quantity (such as pressuregas is absorbed by contact with a liquid.or temperature) in absolute units by means of[ELECTR] A material or device that takes up andsimple physical measurements on the instru-dissipates radiated energy; may be used to shieldment. { abs lut instrmnt } an object from the energy, prevent reflection ofabsolute magnetometer [ENG] An instrumentthe energy, determine the nature of the radiation,used to measure the intensity of a magnetic fieldor selectively transmit one or more componentswithout reference to other magnetic instru-of the radiation. [ENG] The surface on a solarments. { abs lut magn tamdr }collector that absorbs the solar radiation.absolute manometer [ENG] 1. A gas manome-[MECH ENG] 1. A device which holds liquid forter whose calibration, which is the same for all the absorption of refrigerant vapor or otherideal gases, can be calculated from the measur-vapors. 2. That part of the low-pressure side ofable physical constants of the instrument. an absorption system used for absorbing refrig-2. A manometer that measures absolute pres-erant vapor. { b sorbr }sure. { abs lut m namdr }absorber capacity [CHEM ENG] During naturalabsolute pressure gage [ENG] A device that gas processing, the maximum volume of the gasmeasures the pressure exerted by a fluid relativethat can be processed through an absorber with-to a perfect vacuum; used to measure pressures out alteration of specified operating conditions.very close to a perfect vacuum. { abs lut { b sorbr k pasde } preshr gaj } absorber plate [ENG] A part of a flat-plate solarabsolute pressure transducer [ENG] A devicecollector that provides a surface for absorbingthat responds to absolute pressure as the inputincident solar radiation. { b sorbr plat } and provides a measurable output of a nature absorbing boom [CIV ENG] A device that floatsdifferent than but proportional to absolute pres-on the water and is used to stop the spread ofsure. { abs lut preshr tranz dusr } an oil spill and aid in its removal. { b sorbabsolute scale See absolute temperature scale. i bum }{ abs lut skal }absorbing well [CIV ENG] A shaft that permitsabsolute specific gravity [MECH] The ratio ofwater to drain through an impermeable stratumthe weight of a given volume of a substance in to a permeable stratum. { b sorbi wel }a vacuum at a given temperature to the weightabsorption bed [CIV ENG] A sizable pit con-of an equal volume of water in a vacuum at a taining coarse aggregate about a distribution given temperature. { abs lut sp sifk gravpipe system; absorbs the effluent of a septic tank.de }{ b sorpshn bed } absolute stop [CIV ENG] A railway signal which absorption column See absorption tower.indicates that the train must make a full stop { b sorpshn kalm } 2 14. acceleration of free fallabsorption cycle [MECH ENG] In refrigeration,the form of falling droplets. Also known as ab-the process whereby a circulating refrigerant, for sorption column. { b sorpshn taur } example, ammonia, is evaporated by heat from absorption trench [CIV ENG] A trench con-an aqueous solution at elevated pressure and taining coarse aggregate about a distribution tilesubsequently reabsorbed at low pressure, dis-pipe through which septic-tank effluent mayplacing the need for a compressor. { b sorp move beneath earth. { b sorpshn trench } shn skl } absorptivity [THERMO] The ratio of the radia-absorption dynamometer [ENG] A device fortion absorbed by a surface to the total radiationmeasuring mechanical forces or power in whichincident on the surface. { b sorp tivde }the mechanical energy input is absorbed by fric- Abt track [CIV ENG] One of the cogged railstion or electrical resistance. { b sorpshn used for railroad tracking in mountains and sodn mamdr } arranged that the cogs are not opposite one an-absorption-emission pyrometer [ENG] A ther-other on any pair of rails. { apt trak }mometer for determining gas temperature from abutment [CIV ENG] A surface or mass providedmeasurement of the radiation emitted by a cali-to withstand thrust; for example, end supportsbrated reference source before and after this ra-of an arch or a bridge. { btmnt }diation has passed through and been partiallyabutting joint [DES ENG] A joint which connectsabsorbed by the gas. { b sorpshn mishntwo pieces of wood in such a way that the direc-p ramdr } tion of the grain in one piece is angled (usuallyabsorption field [CIV ENG] Trenches containing at 90) with respect to the grain in the other.coarse aggregate about distribution pipes per- { bti joint } mitting septic-tank effluent to seep into sur- abutting tenons [DES ENG] Two tenons insertedrounding soil. Also known as disposal field. into a common mortise from opposite sides so{ b sorpshn feld } that they contact. { bti tennz }absorption hygrometer Also known as chemical ac See alternating current.hygrometer. [ENG] An instrument with which accelerated aging [ENG] Hastening the deteri-the water vapor content of the atmosphere is oration of a product by a laboratory proceduremeasured by means of the absorption of vapor in order to determine long-range storage andby a hygroscopic chemical. { b sorpshn use characteristics. { ak sel radd aji } h gramdr } accelerated life test [ENG] Operation of a de-absorption loss [CIV ENG] The quantity of waterthat is lost during the initial filling of a reservoir vice, circuit, or system above maximum ratingsbecause of absorption by soil and rocks. to produce premature failure; used to estimate{ b sorpshn los } normal operating life. { ak selr add lf absorption meter [ENG] An instrument de-test }signed to measure the amount of light transmit-accelerated weathering [ENG] A laboratory testted through a transparent substance, using a used to determine, in a short period of time,photocell or other light detector. { b sorp the resistance of a paint film or other exposedshn medr }surface to weathering. { ak selr add wethabsorption number [ENG] A dimensionlessri }group used in the field of gas absorption in a accelerating incentive See differential piece-ratewetted-wall column; represents the liquid side system. { ak selr adi in sentiv }mass-transfercoefficient. { b sorpshn accelerating potential [ELECTR] The energy po- nmbr } tential in electron-beam equipment that impartsabsorption plant [CHEM ENG] A facility to re-additional speed and energy to the electrons.cover the condensable portion of natural or refin- { ak selr adi p tenshl } ery gas. { b sorpshn plant } acceleration [MECH] The rate of change ofabsorption process [CHEM ENG] A method invelocity with respect to time. { ak sel ra which light oil is introduced into an absorption shn }tower so that it absorbs the gasoline in the risingacceleration analysis [MECH ENG] A mathe-wet gas; the light oil is then distilled to separate matical technique, often done graphically, bythe gasoline. { b sorpshn prass } which accelerations of parts of a mechanism areabsorption refrigeration [MECH ENG] Refriger-determined. { ak sel rashn nalss }ation in which cooling is effected by the expan- acceleration-error constant [CONT SYS] The ra-sion of liquid ammonia into gas and absorption tio of the acceleration of a controlled variableof the gas by water; the ammonia is reused after of a servomechanism to the actuating error whenthe water evaporates. { b sorpshn r frij the actuating error is constant. { ak sel ra rashn }shn err kanstnt } absorption system [MECH ENG] A refrigeration acceleration measurement [MECH] The tech-system in which the refrigerant gas in the evapo-nique of determining the magnitude and direc-rator is taken up by an absorber and is then, with tion of acceleration, including translational andthe application of heat, released in a generator.angular acceleration. { ak sel rashn mezh{ b sorpshn sistm } rmnt }absorption tower [ENG] A vertical tube in whichacceleration of free fall See acceleration of gravity.a rising gas is partially absorbed by a liquid in{ ak sel rashn v fre fol } 3 15. acceleration of gravityacceleration of gravity [MECH] The accelera-acceptable quality level[IND ENG] The maxi-tion imparted to bodies by the attractive force mum percentage of defects that has been deter-of the earth; has an international standard value mined tolerable as a process average for a sam-of 980.665 cm/s2 but varies with latitude and pling plan during inspection or test of a productelevation. Also known as acceleration of free with respect to economic and functional require-fall; apparent gravity. { ak sel rashn v ments of the item. Abbreviated AQL. { ak gravde } septbl kwalde levl }acceleration signature [IND ENG] A printed re-acceptable reliability level [IND ENG] The re-cord that shows the pattern of acceleration and quired level of reliability for a part, system,device, and so forth; may be expressed in a vari-deceleration of an anatomical reference pointety of terms, for example, number of failuresin the performance of a task. { ak sel rashn allowable in 1000 hours of operating life. Ab- signchr }breviated ARL. { akseptbl r l bilde acceleration tolerance [ENG] The degree to levl }which personnel or equipment withstands accel-acceptance criteria [IND ENG] Standards oferation. { ak sel rashn talrns } judging the acceptability of manufactured items.acceleration voltage [ELECTR] The voltage be- { ak septns kr tere } tween a cathode and accelerating electrode of acceptance number [IND ENG] The maximuman electron tube. { ak sel rashn voltj } allowable number of defective pieces in a sampleaccelerator [MECH ENG] A device for varying of specified size. { ak septns nmbr }the speed of an automotive vehicle by varying acceptance sampling [IND ENG] Taking a sam-the supply of fuel. { ak sel radr } ple from a batch of material to inspect for de-accelerator jet [MECH ENG] The jet throughtermining whether the entire lot will be acceptedwhich the fuel is injected into the incoming airor rejected. { ak septns sampli }in the carburetor of an automotive vehicle with acceptance test [IND ENG] A test used to deter-rapid demand for increased power output. { ak mine conformance of a product to design specifi- sel radr jet } cations, as a basis for its acceptance. { ak sepaccelerator linkage [MECH ENG] The linkagetns test }connecting the accelerator pedal of an automo-acceptor [CHEM ENG] A calcined carbonatetive vehicle to the carburetor throttle valve orused to absorb the carbon dioxide evolved dur-fuel injection control. { ak sel radr likij } ing a coal gasification process. { ak septr }access [CIV ENG] Freedom, ability, or the legalaccelerator pedal [MECH ENG] A pedal that op-right to pass without obstruction from a givenerates the carburetor throttle valve or fuel injec-point on earth to some other objective, such astion control of an automotive vehicle. { ak selthe sea or a public highway. { ak ses } radr pedl } access door [BUILD] A provision for access toaccelerator pump [MECH ENG] A small cylinderconcealed plumbing or other equipment withoutand piston controlled by the throttle of an auto- disturbing the wall or fixtures. { ak ses dor } motive vehicle so as to provide an enriched air-access eye [CIV ENG] A threaded plug fittedfuel mixture during acceleration. { ak sel radinto bends and junctions of drain, waste, or soilr pmp } pipes to provide access when a blockage occurs.accelerogram [ENG] A record made by an ac-See cleanout. { ak ses }celerograph. { ak selr gram } access flooring See raised flooring. { ak sesaccelerograph [ENG] An accelerometer havingflori }provisions for recording the acceleration of aaccess hole See manhole. { ak ses hol } point on the earth during an earthquake or foraccessory [MECH ENG] A part, subassembly, orrecording any other type of acceleration. { akassembly that contributes to the effectiveness selr graf }of a piece of equipment without changing itsaccelerometer [ENG] An instrument which basic function; may be used for testing, ad-measures acceleration or gravitational force ca-justing, calibrating, recording, or other purposes.pable of imparting acceleration. { ak sel ram { ak sesre } dr } access road [CIV ENG] A route, usually paved,accelerometry [IND ENG] The quantitative de-that enables vehicles to reach a designated facil-ity expeditiously. { akses rod } termination of acceleration and deceleration inaccess tunnel [CIV ENG] A tunnel provided forthe entire human body or a part of the body inan access road. { akses tnl }the performance of a task. { ak sel ram accident-cause code [IND ENG] Sponsored bydre } the American Standards Association, the codeaccent lighting [CIV ENG] Directional lightingthat classifies accidents under eight defectivewhich highlights an object or attracts attentionworking conditions and nine improper workingto a particular area. { aksent ldi } practices. { aks dent koz kod } acceptability [ENG] State or condition of meet- accident frequency rate [IND ENG] The numbering minimum standards for use, as applied toof all disabling injuries per million worker-hoursmethods, equipment, or consumable products. of exposure. { aks dent frekwnse rat } { ak sept bilde } accident severity rate [IND ENG] The number of4 16. acme screw threadworker-days lost as a result of disabling injuries acfm See actual cubic feet per minute.per thousand worker-hours of exposure. { ak acid blowcase See blowcase. { asd blokas } s dent s verde rat } acid cleaning [ENG] The use of circulating acidaccommodation [CONT SYS] Any alteration in a to remove dirt, scale, or other foreign matterrobots motion in response to the robots envi-from the interior of a pipe. { asd kleni }ronment; it may be active or passive. { kamacid conductor [CHEM ENG] A vessel designed dashn }for refortification of hydrolyzed acid by heatingaccordion door [BUILD] A door that folds and and evaporation of water, or sometimes by dis-unfolds like an accordion when it is opened andtillation of water under partial vacuum. { asclosed. { korden dor } d kn dktr }accordion partition [BUILD] A movable, fabric- acid egg See blowcase. { asd eg }faced partition which is fitted into an overhead acid gases [CHEM ENG] The hydrogen sulfidetrack and folds like an accordion. { korden and carbon dioxide found in natural and refinerypr tishn }gases which, when combined with moisture,accordion roller conveyor [MECH ENG] A con-form corrosive acids; known as sour gases whenveyor with a flexible latticed frame which permits hydrogen sulfide and mercaptans are present.variation in length. { korden rolr kn { asd gasz } var }aciding [ENG] A light etching of a building sur-accretion [CIV ENG] Artificial buildup of land face of cast stone. { asdi }due to the construction of a groin, breakwater,acid lining [ENG] In steel production, a silica-dam, or beach fill. { kreshn }brick lining used in furnaces. { asd lni }accumulated discrepancy [ENG] The sum of acid number [ENG] A number derived from athe separate discrepancies which occur in thestandard test indicating the acid or base compo-various steps of making a survey. { kyumy sition of lubricating oils; it in no way indicates ladd d skrepnse } the corrosive attack of the used oil in service.accumulative timing [IND ENG] A time-study Also known as corrosion number. { asdmethod that allows direct reading of the timenmbr }for each element of an operation by the useacid polishing [ENG] The use of acids to polishof two stopwatches which operate alternately.a glass surface. { asd palishi }{ kyumy ladiv tmi } acid process [CHEM ENG] In paper manufac-accumulator [CHEM ENG] An auxiliary ram ex-ture, a pulp digestion process that uses an acidictruder on blow-molding equipment used to store reagent, for example, a bisulfite solution con-melted material between deliveries. [ENG]taining free sulfur dioxide. { asd prass } See air vessel. [MECH ENG] 1. A device, suchacid recovery plant [CHEM ENG] In some refin-as a bag containing pressurized gas, which actseries, a facility for separating sludge acid intoupon hydraulic fluid in a vessel, discharging it acid oil, tar, and weak sulfuric acid, with provi-rapidly to give high hydraulic power, after whichsion for later reconcentration. { asd r kvthe fluid is returned to the vessel with the use re plant } of low hydraulic power. 2. A device connectedacid sludge [CHEM ENG] The residue left afterto a steam boiler to enable a uniform boiler treating petroleum oil with sulfuric acid for theoutput to meet an irregular steam demand. 3. removal of impurities. { asd slj }A chamber for storing low-side liquid refrigerantacid soot [ENG] Carbon particles that havein a refrigeration system. Also known as surge absorbed acid fumes as a by-product of combus-drum; surge header. { kyumy ladr } tion; hydrochloric acid absorbed on carbon par-accustomization [ENG] The process of learningticulates is frequently the cause of metal corro-the techniques of living with a minimum of dis-sion in incineration. { asd sut } comfort in an extreme or new environment.acid treatment [CHEM ENG] A refining process{ kstm zashn }in which unfinished petroleum products, such asacetate process [CHEM ENG] Acetylation ofgasoline, kerosine, and diesel oil, are contactedcellulose (wood pulp or cotton linters) with ace-with sulfuric acid to improve their color, odor,tic acid or acetic anhydride and sulfuric acid cata- and other properties. { asd tretmnt } lyst to make cellulose acetate resin or fiber. acid-water pollution [ENG] Industrial wastewa-{ as tat prass } ters that are acidic; usually appears in effluentacetone-benzol process [CHEM ENG] A dewax- from the manufacture of chemicals, batteries,ing process in petroleum refining, with acetoneartificial and natural fiber, fermentation proc-and benzol used as solvents. { as ton benesses (beer), and mining. { asd wodr zol prass } p lushn }acetylene cutting See oxyacetylene cutting.Ackerman linkage See Ackerman steering gear.{ sedl en kti } { akrmn likij }acetylene generator [ENG] A steel cylinder oracme screw thread [DES ENG] A standardtank that provides for controlled mixing of cal- thread having a profile angle of 29 and a flatcium carbide and water to generate acetylene.crest; used on power screws in such devices as{ sedl en jen radr } automobile jacks, presses, and lead screws onacetylene torch See oxyacetylene torch. { sed lathes. Also known as acme thread. { akme l en torch } skru thred } 5 17. acme threadacme thread See acme screw thread. { akme acoustic generator[ENG ACOUS] A transducerthred }which converts electrical, mechanical, or otheracoubuoy [ENG] An acoustic listening deviceforms of energy into sound. { kustik jen similar to a sonobuoy, used on land to form an radr }electronic fence that will pick up sounds of en- acoustic heat engine [ENG] A device that trans-emy movements and transmit them to orbitingforms heat energy first into sound energy andaircraft or land stations. { ku boi } then into electrical power, without the use ofacoustical ceiling [BUILD] A ceiling covered moving mechanical parts. { kustik het en with or built of material with special acousticaljn }properties. { kustkl seli } acoustic hologram [ENG] The phase interfer-acoustical ceiling system [BUILD] A system for ence pattern, formed by acoustic beams, that isthe structural support of an acoustical ceiling; used in acoustical holography; when light islighting and air diffusers may be included as part made to interact with this pattern, it forms anof the system. { kustkl seli sistm } image of an object placed in one of the beams.acoustical door [BUILD] A solid door with gas- { kustik hal gram } keting along the top and sides, and usually an acoustic horn See horn. { kustik horn }automatic door bottom, designed to reduceacoustic jamming [ENG ACOUS] The deliberatenoise transmission. { kustkl dor } radiation or reradiation of mechanical or electro-acoustical model [CIV ENG] A model used to acoustic signals with the objectives of obliterat-investigate certain acoustical properties of aning or obscuring signals which the enemy isauditorium or room such as sound pressure dis- attempting to receive and of deterring enemytribution, sound-ray paths, and focusing effects.weapons systems. { kustik jami } { kustkl madl } acoustic labyrinth [ENG ACOUS] Special baffleacoustical treatment [CIV ENG] That part of arrangement used with a loudspeaker to preventbuilding planning that is designed to provide a cavity resonance and to reinforce bass response.proper acoustical environment; includes the use { kustik lab rinth } of acoustical material. { kustkl tret acoustic line [ENG ACOUS] The acoustic equiv-mnt } alent of an electrical transmission line, involvingacoustic array [ENG ACOUS] A sound-transmit- baffles, labyrinths, or resonators placed at theting or sound-receiving system whose elementsare arranged to give desired directional charac- rear of a loudspeaker and arranged to help repro-teristics. { kustik ra }duce the very low audio frequencies. { kus acoustic center [ENG ACOUS] The center of thetik ln } spherical sound waves radiating outward from acoustic ocean-current meter [ENG] An instru-an acoustic transducer. { kustik sentr }ment that measures current flow in rivers andacoustic clarifier [ENG ACOUS] System of cones oceans by transmitting acoustic pulses in oppo-loosely attached to the baffle of a loudspeakersite directions parallel to the flow and measuringand designed to vibrate and absorb energy dur- the difference in pulse travel times betweening sudden loud sounds to suppress these transmitter-receiver pairs. { kustik oshn sounds. { kustik klar fr } krnt medr }acoustic coupler [ENG ACOUS] A device used acoustic position reference system [ENG] Anbetween the modem of a computer terminal and acoustic system used in offshore oil drilling toa standard telephone line to permit transmission provide continuous information on ship positionof digital data in either direction without making with respect to an ocean-floor acoustic beacondirect connections. { kustik kplr }transmitting an ultrasonic signal to three hy-acoustic delay [ENG ACOUS] A delay which isdrophones on the bottom of the drilling ship.deliberately introduced in sound reproduction{ kustik p zishn refrns sistm } by having the sound travel a certain distanceacoustic radar [ENG] Use of sound waves withalong a pipe before conversion into electric sig-radar techniques for remote probing of the lowernals. { kustik di la } atmosphere, up to heights of about 5000 feetacoustic detection [ENG] Determination of the(1500 meters), for measuring wind speed andprofile of a geologic formation, an ocean layer, direction, humidity, temperature inversions, andor some object in the ocean by measuring the turbulence. { kustik ra dar } reflection of sound waves off the object.acoustic radiator [ENG ACOUS] A vibrating sur-{ kustik di tekshn } face that produces sound waves, such as a loud-acoustic fatigue [MECH] The tendency of a ma-speaker cone or a headphone diaphragm.terial, such as a metal, to lose strength after{ kustik rade adr } acoustic stress. { kustik f teg } acoustic radiometer [ENG] An instrument foracoustic feedback [ENG ACOUS] The reverbera- measuring sound intensity by determining thetion of sound waves from a loudspeaker to aunidirectional steady-state pressure caused bypreceding part of an audio system, such as tothe reflection or absorption of a sound wave atthe microphone, in such a manner as to rein- a boundary. { kustik rad amdr } force, and distort, the original input. Also acoustic ratio [ENG ACOUS] The ratio of the in-known as acoustic regeneration. { kustik tensity of sound radiated directly from a source fed bak }to the intensity of sound reverberating from the 6 18. active accommodationwalls of an enclosure, at a given point in theelectronics that involves use of acoustic waves atenclosure. { kustik rasho } microwave frequencies (above 500 megahertz),acoustic reflex enclosure [ENG ACOUS] A loud- traveling on or in piezoelectric or other solidspeaker cabinet designed with a port to allow a substrates. Also known as pretersonics.low-frequency contribution from the rear of the { kusto lektraniks } speaker cone to be radiated forward. { kus acquisition [ENG] The process of pointing antik re fleks in klozhr } antenna or a telescope so that it is properlyacoustic regeneration See acoustic feedback.oriented to allow gathering of tracking or teleme-{ kustik re jen rashn } try data from a satellite or space probe. { akacoustic seal [ENG ACOUS] A joint between two w zishn }parts to provide acoustical coupling with low acquisition and tracking radar [ENG] A radarlosses of energy, such as between an earphone set capable of locking onto a received signal andand the human ear. { kustik sel } tracking the object emitting the signal; the radaracoustic signature [ENG] In acoustic detection, may be airborne or on the ground. { akthe profile characteristic of a particular object w zishn n traki ra dar } or class of objects, such as a school of fish oracre [MECH] A unit of area, equal to 43,560a specific ocean-bottom formation. { kustik square feet, or to 4046.8564224 square meters. signchr }{ akr } acoustic spectrograph [ENG] A spectrographacrometer [ENG] An instrument to measure theused with sound waves of various frequenciesdensity of oils. { kramdr }to study the transmission and reflection proper-actinogram [ENG] The record of heat from aties of ocean thermal layers and marine life. source, such as the sun, as detected by a re-{ kustik spektr graf }cording actinometer. { ak tin gram }acoustic spectrometer [ENG ACOUS] An instru-actinograph [ENG] A recording actinometer.ment that measures the intensities of the various{ ak tin graf }frequency components of a complex sound wave.actinometer [ENG] Any instrument used toAlso known as audio spectrometer. { kustikmeasure the intensity of radiant energy, particu-spek tramdr } larly that of the sun. { akt namdr }acoustic strain gage [ENG] An instrument usedaction [MECH] An integral associated with thefor measuring structural strains; consists of alength of fine wire mounted so its tension varies trajectory of a system in configuration space,with strain; the wire is plucked with an electro- equal to the sum of the integrals of the general-magnetic device, and the resulting frequency of ized momenta of the system over their canoni-vibration is measured to determine the amount cally conjugate coordinates. Also known asof strain. { kustik stran gaj } phase integral. { akshn }acoustic theodolite [ENG] An instrument thatactivate [ELEC] To make a cell or battery opera-uses sound waves to provide a continuous verti- tive by addition of a liquid. [ELECTR] To treatcal profile of ocean currents at a specific location. the filament, cathode, or target of a vacuum tube{ kustik the adl t } to increase electron emission. [ENG] To setacoustic transducer [ENG ACOUS] A device that up conditions so that the object will function asconverts acoustic energy to electrical or mechan- designed or required. { akt vat } ical energy, such as a microphone or phonograph activated sludge [CIV ENG] A semiliquid masspickup. { kustik tranz dusr } removed from the liquid flow of sewage and sub-acoustic transformer [ENG ACOUS] A device,jected to aeration and aerobic microbial action;such as a horn or megaphone, for increasing the the end product is dark to golden brown, partiallyefficiency of sound radiation. { kustik tranz decomposed, granular, and flocculent, and has formr } an earthy odor when fresh. { akt vadd acoustic treatment [BUILD] The use of sound- slj }absorbing materials to give a room a desiredactivated-sludge effluent [CIV ENG] The liquiddegree of freedom from echo and reverberation.from the activated-sludge treatment that is fur-{ kustik tretmnt } ther processed by chlorination or by oxidation.acoustic-wave-based sensor [ENG] A device { akt vadd slj ef lunt } that employs a surface acoustic wave, a thick-activated-sludge process [CIV ENG] A sewageness-shear-mode resonance (a resonant oscilla-treatment process in which the sludge in thetion of a thin plate of material), or other type of secondary stage is put into aeration tanks toacoustic wave to measure the physical propertiesfacilitate aerobic decomposition by microorgan-of a thin film or liquid layer or, in combination isms; the sludge and supernatant liquor are sep-with chemically sensitive thin films, to detect arated in a settling tank; the supernatant liquorthe presence and concentration of chemical ana- or effluent is further treated by chlorination orlytes. { kustik wav bast sensr } oxidation. { akt vadd slj pra ss } acoustic well logging [ENG] A ground explora- active accommodation [CONT SYS] The alter-tion method that uses a high-energy sound ation of preprogrammed robotic motions by thesource and a receiver, both underground.integrated effects of sensors, controllers, and the{ kustik wel lagi } robotic motion itself. { aktiv kam da acoustoelectronics [ENG ACOUS] The branch ofshn }7 19. active areaactive area [ELECTR] The area of a metallic rec- activity [SYS ENG] The representation in a PERTtifier that acts as the rectifying junction and con- or critical-path-method network of a task thatducts current in the forward direction. { aktiv takes up both time and resources and whose ere } performance is necessary for the system to moveactive-cord mechanism [MECH ENG] A slender,from one event to the next. { ak tivde } chainlike grouping of joints and links that makesactivity chart [IND ENG] A tabular presentationactive and flexible winding motions under theof a series of operations of a process plottedcontrol of actuators attached along its body.against a time scale. { ak tivde chart } { aktiv kord mek nizm }activity duration [SYS ENG] In critical-path-active detection system [ENG] A guidance sys-method terminology, the estimated amount oftem which emits energy as a means of detection;time required to complete an activity. { ak tivfor example, sonar and radar. { aktiv di tek de d rashn } shn sistm } activity sampling See work sampling. { ak tivdactive earth pressure [CIV ENG] The horizontal e sampli } pressure that an earth mass exerts on a wall. actual cost [IND ENG] Cost determined by an{ aktiv rth preshr }active illumination [ENG] Lighting whose direc-allocation of cost factors recorded during pro-tion, intensity, and pattern are controlled by duction. { akchwl kost } commands or signals. { aktiv lum na actual cubic feet per minute [CHEM ENG] Ashn } measure of the volume of gas at operating tem-active infrared detection system [ENG] An in-perature and pressure, as distinct from volumefrared detection system in which a beam of infra-of gas at standard temperature and pressure.red rays is transmitted toward possible targets, Abbreviated acfm. { akchwl kyubik fet and rays reflected from a target are detected. pr mint }{ aktiv infr red di tekshn sistm }actual horsepower See actual power. { akchactive leaf [BUILD] In a door with two leaves, wl hors paur }the leaf which carries the latching or locking actual power [MECH ENG] The power deliveredmechanism. Also known as active door. { akat the output shaft of a source of power. Alsotiv lef } known as actual horsepower. { akchwlactive material [ELEC] 1. A fluorescent materialpaur } used in screens for cathode-ray tubes. 2. An actual time [IND ENG] Time taken by a workerenergy-storing material, such as lead oxide, usedto perform a given task. { akchwl tm } in the plates of a storage battery. 3. A material, actuate [MECH ENG] To put into motion orsuch as the iron of a core or the copper of amechanical action, as by an actuator. { akwinding, that is involved in energy conversion inchwat } a circuit. 4. In a battery, the chemically reactiveactuated roller switch [MECH ENG] A centrifu-material in either of the electrodes that partici- gal sequence-control switch that is placed inpates in the charge and discharge reactions. contact with a belt conveyor, immediately pre-[ELECTR] The material of the cathode of an elec- ceding the conveyor which it controls. { aktron tube that emits electrons when heated.ch wadd rolr swich } { aktiv m tirel }actuating system [CONT SYS] An electric, hy-active sludge [CIV ENG] A sludge rich in de- draulic, or other system that supplies and trans-structive bacteria used to break down raw sew- mits energy for the operation of other mecha-age. { aktiv slj } nisms or systems. { akch wadi sistm }active solar system [MECH ENG] A solar heat- actuator [CONT SYS] A mechanism to activateing or cooling system that operates by mechani-process control equipment by use of pneumatic,cal means, such as motors, pumps, or valves. hydraulic, or electronic signals; for example, a{ aktiv solr sistm }valve actuator for opening or closing a valve toactive sonar [ENG] A system consisting of one control the rate of fluid flow. [ENG ACOUS] Anor more transducers to send and receive sound, auxiliary external electrode used to apply aequipment for the generation and detection ofthe electrical impulses to and from the trans- known electrostatic force to the diaphragm of aducer, and a display or recorder system for themicrophone for calibration purposes. Alsoobservation of the received signals. { aktivknown as electrostatic actuator. [MECH ENG] so nar } A device that produces mechanical force byactive system [ENG] In radio and radar, a sys- means of pressurized fluid. { akch wadr } tem that requires transmitting equipment, such adamantine drill [MECH ENG] A core drill withas a beacon or transponder. { aktiv sistm } hardened steel shot pellets that revolve underactive vibration suppression [MECH ENG] Thethe rim of the rotating tube; employed in rotaryprevention of undesirable vibration by tech- drilling in very hard ground. { ad man tenniques involving feedback control of the vibra- dril }tory motion, whereby the forces designed to re-Adams catalyst [CHEM ENG] Finely dividedduce the vibration depend on the system dis- plantinum(IV) oxide, made by fusing hexachloro-placements and velocities. { aktiv v brashn platinic(IV) acid with NaNO3. { admz kads preshn }lst } 8 20. adjustable base anchorada mud [ENG] A conditioning material addedharmonically related frequencies. { addivto drilling mud to obtain satisfactory cores andsinthss }samples of formations. { ad md } adhesion[ENG] Intimate sticking together ofadapter [ENG] A device used to make electrical metal surfaces under compressive stresses byor mechanical connections between items notformation of metallic bonds. [MECH] Theoriginally intended for use together. { dap force of static friction between two bodies, ortr }the effects of this force. { ad hezhn } adaptive branch [CONT SYS] A branch instruc- adhesional work [THERMO] The work requiredtion in the computer program controlling a robot to separate a unit area of a surface at which twothat may lead the robot to execute a series of substances are in contact. Also known as workinstructions, depending on external conditions.of adhesion. { ad hezhnl wrk } { daptiv branch } adhesive bond [MECH] The forces such as di-adaptive control [CONT SYS] A control method pole bonds which attract adhesives and basein which one or more parameters are sensed and materials to each other. { ad heziv band } used to vary the feedback control signals in order adhesive bonding [ENG] The fastening to-to satisfy the performance criteria. { daptiv gether of two or more solids by the use of glue,kn trol } cement, or other adhesive. { ad heziv band adaptive-control function [CONT SYS] Thati }level in the functional decomposition of a large-adhesive strength [ENG] The strength of an ad-scale control system which updates parametershesive bond, usually measured as a force re-of the optimizing control function to achieve aquired to separate two objects of standardbest fit to current plant behavior, and updatesbonded area, by either shear or tensile stress.parameters of the direct control function to { ad heziv strekth } adiabatic [THERMO] Referring to any change inachieve good dynamic response of the closed- which there is no gain or loss of heat. { ade loop system. { daptiv kn trol fkshn } badik }adaptive robot [CONT SYS] A robot that can al- adiabatic compression [THERMO] A reductionter its responses according to changes in the in volume of a substance without heat flow, inenvironment. { daptiv ro bat } or out. { adebadik km preshn }adaptive structure [ENG] A structure whose adiabatic cooling [THERMO] A process in whichgeometric and inherent structural characteristicsthe temperature of a system is reduced withoutcan be changed beneficially in response to exter-any heat being exchanged between the systemnal stimulation by either remote commands or and its surroundings. { adebadik kuli } automatic means. { daptiv strkchr }adiabatic curing [ENG] The curing of concreteadaptive system [SYS ENG] A system that canor mortar under conditions in which there is nochange itself in response to changes in its envi-loss or gain of heat. { adebadik kyuri } ronment in such a way that its performance im- adiabatic engine [MECH ENG] A heat engine orproves through a continuing interaction with its thermodynamic system in which there is no gainsurroundings. { daptiv sistm }or loss of heat. { adebadik enjn } adaptometer [ENG] An instrument that meas- adiabatic envelope [THERMO] A surface en-ures the lowest brightness of an extended area closing a thermodynamic system in an equilib-that can barely be detected by the eye.rium which can be disturbed only by long-range{ a dap tamdr } forces or by motion of part of the envelope; intu-addendum [DES ENG] The radial distance be- itively, this means that no heat can flow throughtween two concentric circles on a gear, one beingthe surface. { adebadik env lop } that whose radius extends to the top of a gear adiabatic expansion [THERMO] Increase in vol-tooth (addendum circle) and the other being that ume without heat flow, in or out. { adebadwhich will roll without slipping on a circle on aik ik spanchn }mating gear (pitch line). { dendm }adiabatic extrusion [ENG] Forming plastic ob-addendum circle [DES ENG] The circle on a gear jects by energy produced by driving the plasticpassing through the tops of the teeth. { denmass through an extruder without heat flow.dm srkl }{ adebadik ik struzhn }adder [ELECTR] A circuit in which two or moreadiabatic process [THERMO] Any thermody-signals are combined to give an output-signalnamic procedure which takes place in a systemamplitude that is proportional to the sum of the without the exchange of heat with the surround-input-signal amplitudes. Also known as adder ings. { adebadik prass }circuit. { adr } adiabatic vaporization [THERMO] Vaporizationadding tape [ENG] A surveyors tape that is cali-of a liquid with virtually no heat exchange be-brated from 0 to 100 by full feet (or meters) in one tween it and its surroundings. { adebadik direction, and has 1 additional foot (or meter) vapr zashn } beyond the zero end which is subdivided in adit [CIV ENG] An access tunnel used for excava-tenths or hundredths. { adi tap } tion of the main tunnel. { adt }additive synthesis [ENG ACOUS] A method of adjustable base anchor [BUILD] An item whichsynthesizing complex tones by adding togetherholds a doorframe above a finished floor.an appropriate number of simple sine waves at{ jstbl bas akr } 9 21. adjustable parallelsadjustable parallels [ENG] Wedge-shaped ironblock that is not completely cleared. { d vansbars placed with the thin end of one on the thicksignl }end of the other, so that the top face of the upper advance slope grouting [ENG] A grouting tech-and the bottom face of the lower remain parallel, nique in which the front of the mass of grout isbut the distance between the two faces is adjust- forced to move horizontally through preplacedable; the bars can be locked in position by a aggregate. { d vans slop graudi } screw to prevent shifting. { jstbl paradvance slope method [ENG] A method of con- lelz }crete placement in which the face of the freshadjustable square [ENG] A try square with anconcrete, which is not vertical, moves forwardarm that is at right angles to the ruler; the posi- as the concrete is placed. { d vans slop tion of the arm can be changed to form an L or methd }a T. Also known as double square. { jst adz [DES ENG] A cutting tool with a thin archedbl skwer } blade, sharpened on the concave side, at rightadjustable wrench [ENG] A wrench with one angles on the handle; used for rough dressingjaw which is fixed and another which is adjust- of timber. { adz }able; the size is adjusted by a knurled screw.adz block [MECH ENG] The part of a machine{ jstbl rench }for wood planing that carries the cutters.adjusting [ENG] In measurement technology,{ adz blak } setting or compensating a measuring instrumentaerated flow [ENG] Flowing liquid in which gasor a weight in such a way that the indicated valueis dispersed as fine bubbles throughout the liq-deviates as little as possible from the actualuid. { e radd flo } value. { jsti }aeration [ENG] 1. Exposing to the action of air.adjutage [ENG] A tube attached to a container2. Causing air to bubble through. 3. Introduc-of liquid at an orifice to facilitate or regulateing air into a solution by spraying, stirring, oroutflow. { aj tazh }similar method. 4. Supplying or infusing withadmittance [ELEC] A measure of how readilyair, as in sand or soil. { e rashn }alternating current will flow in a circuit; the recip-aeration tank [ENG] A fluid-holding tank withrocal of impedance, it is expressed in siemens.provisions to aerate its contents by bubbling air{ d mitns }or another gas through the liquid or by sprayingadobe construction [BUILD] Wall constructionwith sun-dried blocks of adobe soil. { dobethe liquid into the air. { e rashn tak } aerator [DES ENG] A tool having a rollerkn strkshn }ADP See automatic data processing.equipped with hollow fins; used to remove coresADR studio [ENG ACOUS] A sound-recordingof soil from turf. [ENG] 1. One who aerates.studio used in motion-picture and television2. Equipment used for aeration. 3. Any deviceproduction to allow an actor who did not intelli- for supplying air or gas under pressure, as forgibly record his or her speech during the originalfumigating, welding, or ventilating. [MECHfilming or video recording to do so by watching ENG] Equipment used to inject compressedhimself or herself on the screen and repeatingair into sewage in the treatment process.the original speech with lip synchronism; it is { e radr } equipped with facilities for recreating the acous-aerial cableway See aerial tramway. { erel tical liveness and background sound of the envi- kabl wa } ronment of the original dialog. Derived fromaerial photogrammetry [ENG] Use of aerialautomatic dialog replacement studio. Also photographs to make accurate measurements inknown as postsynchronizing studio. { ade ar surveying and mapmaking. { erel fot studeo } gramtre }adsorption system [MECH ENG] A device thataerial photographic reconnaissance See aerialdehumidifies air by bringing it into contact with photoreconnaissance. { erel fodgrafik a solid adsorbing substance. { ad sorpshnri kansns } sistm }aerial photography [ENG] The making of photo-advance [CIV ENG] In railway engineering, a graphs of the ground surface from an aircraft,length of track that extends beyond the signalspacecraft, or rocket. Also known as aeropho-that controls it. [MECH ENG] To effect the ear- tography. { erel f tagrfe } lier occurrence of an event, for example, spark aerial photoreconnaissance [ENG] The ob-advance or injection advance. { d vans } taining of information by air photography;advanced programmatic risk analysis[IND the three types are strategic, tactical, and sur-ENG] A method for managing engineering pro- vey-cartographic photoreconnaissance. Alsograms with multiple projects and strict resourceknown as aerial photographic reconnaissance.constraints which balances both technical and { erel fodo ri kansns } management risks. { dvanst progrmadik aerial reconnaissance [ENG] The collection of risk nalss }information by visual, electronic, or photo-advanced sewage treatment See tertiary sewage graphic means while aloft. { erel ri kan treatment. { dvanst suij tretmnt } sns }advance signal [CIV ENG] A signal in a blockaerial ropeway See aerial tramway. { erelsystem up to which a train may proceed within arop wa } 10 22. afterfilteraerial spud [MECH ENG] A cable for moving andaerograph[ENG] Any self-recording instrumentanchoring a dredge. { erel spd } carried aloft by any means to obtain meteoro-aerial survey [ENG] A survey utilizing photo-logical data. { ero graf } graphic, electronic, or other data obtained from aerometeorograph [ENG] A self-recording in-an airborne station. Also known as aerosurvey; strument used on aircraft for the simultaneousair survey. { erel srva } recording of atmospheric pressure, temperature,aerial tramway [MECH ENG] A system for trans-and humidity. { ero mede or graf } porting bulk materials that consists of one or aerometer [ENG] An instrument to ascertainmore cables supported by steel towers and is the weight or density of air or other gases.capable of carrying a traveling carriage from{ e ramdr }which loaded buckets can be lowered or raised. aerophotography See aerial photography. { eroAlso known as aerial cableway; aerial ropeway. f tagr fe } { erel tram wa } aerosol generator [MECH ENG] A mechanicalaeroballistics [MECH] The study of the interac-means of producing a system of dispersed phasetion of projectiles or high-speed vehicles withand dispersing medium, that is, an aerosol.the atmosphere. { erob listiks } { er sol jen radr } aerobic-anaerobic interface [CIV ENG] That aerospace engineering [ENG] Engineering per-point in bacterial action in the body of a sewagetaining to the design and construction of aircraftsludge or compost heap where both aerobic andand space vehicles and of power units, and toanaerobic microorganisms participate, and thethe special problems of flight in both the earthsdecomposition of the material goes no further. atmosphere and space, as in the flight of air{ e robik an robik intr fas }vehicles and in the launching, guidance, andaerobic-anaerobic lagoon [CIV ENG] A pond in control of missiles, earth satellites, and spacewhich the solids from a sewage plant are placed vehicles and probes. { erospas enj niri } in the lower layer; the solids are partially decom- aerospace industry [ENG] Industry concernedposed by anaerobic bacteria, while air or oxygen with the use of vehicles in both the earths at-is bubbled through the upper layer to create an mosphere and space. { erospas indstre } aerobiccondition. { e robik an robik aerostatic balance [ENG] An instrument for l gun } weighing air. { erostadik balns } aerobic digestion [CHEM ENG] Digestion of aerosurvey See aerial survey. { erosr va } matter suspended or dissolved in waste by aerotrain [ENG] A train that is propelled by amicroorganisms under favorable conditions ofoxygenation. { e robik d jeschn } fan jet engine and floats on a cushion of low-aerobic lagoon [CIV ENG] An aerated pond inpressure air, traveling at speeds up to 267 mileswhich sewage solids are placed, and are decom- (430 kilometers) per hour. { ero tran } posed by aerobic bacteria. Also known as aero- aesthesiometer See esthesiometer. { es thebic pond. { e robik l gun } ze amdr } aerobic pond See aerobic lagoon. { erobik affreightment [IND ENG] The lease of a vessel pand }for the transportation of goods. { fratmnt }aerochlorination [CIV ENG] Treatment of sew- A frame [BUILD] A dwelling whose main framesage with compressed air and chlorine gas to re-are in the shape of the letter A. [ENG] Twomove fatty substances. { ero klor nashn } poles supported in an upright position by bracesaerodrome See airport. { ero drom } or guys and used for lifting equipment. Alsoaerodynamic balance [ENG] A balance used for known as double mast. { a fram } the measurement of the forces exerted on the afterboil [MECH ENG] In an automotive engine,surfaces of instruments exposed to flowing air;coolant boiling after the engine has stopped be-frequently used in tests made on models in windcause of the inability of the engine at rest totunnels. { erod namik balns } dissipate excess heat. { aftr boil }aerodynamic trajectory [MECH] A trajectory orafterburning [MECH ENG] Combustion in an in-part of a trajectory in which the missile or vehicle ternal combustion engine following the maxi-encounters sufficient air resistance to stabilizemum pressure of explosion. { aftr brni }its flight or to modify its course significantly.aftercondenser [MECH ENG] A condenser in{ erod namik tr jektre } the second stage of a two-stage ejector; used inaeroelasticity [MECH]The deformation ofsteam power plants, refrigeration systems, andstructurally elastic bodies in response to aerody- air conditioning systems. { aftrkn densnamic loads. { eroi las tisde } r }aerofall mill [MECH ENG] A grinding mill ofaftercooler [MECH ENG] A heat exchangerlarge diameter with either lumps of ore, pebbles,which cools air that has been compressed; usedor steel balls as crushing bodies; the dry load is on turbocharged engines. { aftr kulr }airswept to remove mesh material. { ero fol aftercooling [MECH ENG] The cooling of a gas mil } after its compression. { aftr kuli }aerofilter [CIV ENG] A filter bed for sewage treat-afterfilter [MECH ENG] In an air-conditioningment consisting of coarse material and operatedsystem, a high-efficiency filter located near a ter-at high speed, often with recirculation. { eminal unit. Also known as final filter. { afro filtr }tr filtr }11 23. afterrunningafterrunning [MECH ENG] In an automotive en- agricultural pipe drain [CIV ENG] A system ofgine, continued operation of the engine after theporous or perforated pipes laid in a trench filledignition switch is turned off. Also known as with gravel or the like; used for draining subsoil.dieseling; run-on. { aftr rni } { agrklchrl pp dran } after top dead center [MECH ENG] The positionagricultural robot [CONT SYS] A robot used toof the piston after reaching the top of its stroke pick and harvest farm products and fruits. { agin an automotive engine. { aftr tap ded rklchrl ro bat } sentr } AGV See automated guided vehicle.agger [CIV ENG] A material used for road fillaided tracking [ENG] A system of radar-trackingover low ground. { ajr } a target signal in bearing, elevation, or range, oraggregate bin [ENG] A structure designed for any combination of these variables, in which thestoring and dispensing dry granular construction rate of motion of the tracking equipment is ma-materials such as sand, crushed stone, and chine-controlled in collaboration with an opera-gravel; usually has a hopperlike bottom that fun-tor so as to minimize tracking error. { addnels the material to a gate under the structure.traki }{ agrgt bin }aided-tracking mechanism [ENG] A device con-aggregate interlock [ENG] The projection of ag-sisting of a motor and variable-speed drive whichgregate particles or portions thereof from one provides a means of setting a desired trackingside of a joint or crack in concrete into recesses rate into a director or other fire-control instru-in the other side so as to effect load transfer in ment, so that the process of tracking is carriedcompression and shear, and to maintain mutualout automatically at the set rate until it isalignment. { agrgt intr lak }changed manually. { add traki mekaggregate production scheduling [IND ENG] A nizm }type of planning at a broad level without consid- aided-tracking ratio [ENG] The ratio betweeneration of individual products and activities in the constant velocity of the aided-tracking mech-order to develop a program of output that will anism and the velocity of the moving target.meet future demand under given constraints. { add traki rasho } { agrigt prdkshn skejli } aiguille [ENG] A slender form of drill used foraggressive carbon dioxide [CHEM ENG] The boring or drilling a blasthole in rock. { a gwel } carbon dioxide dissolved in water in excess of aiming circle [ENG] An instrument for measur-the amount required to precipitate a specifiedconcentration of calcium ions as calcium carbon- ing angles in azimuth and elevation in connec-ate; used as a measure of the corrosivity andtion with artillery firing and general topographicscaling properties of water. { gresiv kar work; equipped with fine and coarse azimuthbn d ak sd } micrometers and a magnetic needle. { ami agile manufacturing [IND ENG] Operations that srkl }can be rapidly reconfigured to satisfy changingaiming screws [MECH ENG] On an automotivemarket demands. { ajl manyu fakchri }vehicle, spring-loaded screws designed to secureaging [ELEC] Allowing a permanent magnet,headlights to a support frame and permit aimingcapacitor, meter, or other device to remain in of the headlights in horizontal and verticalstorage for a period of time, sometimes with a planes. { aimi skruz }voltage applied, until the characteristics of theAIR See air-injection reactor. { er }device become essentially constant. [ENG]air-actuated [ENG] Powered by compressed air.1. The changing of the characteristics of a device { er akch wadd }due to its use. 2. Operation of a product before air-arc furnace [ENG] An arc furnace designedshipment to stabilize characteristics or detectto power wind tunnels, the air being superheatedearly failures. { aji }to 20,000 K and expanded to emerge at super-agitating speed [MECH ENG] The rate of rota- sonic speeds. { er ark frns } tion of the drum or blades of a truck mixer or air aspirator valve [MECH ENG] On certain au-other device used for agitation of mixed con-tomotive engines, a one-way valve installed oncrete. { aj tadi sped } the exhaust manifold to allow air to enter theagitating truck [MECH ENG] A vehicle carryingexhaust system; provides extra oxygen to converta drum or agitator body, in which freshly mixedcarbon monoxide to carbon dioxide. Alsoconcrete can be conveyed from the point of mix-known as gulp valve. { er asp radr valv } ing to that of placing, the drum being rotated air-assist forming [ENG] A plastics thermo-continuously to agitate the contents. { ajforming method in which air pressure is used to tadi trk }partially preform a sheet before it enters theagitator [MECH ENG] A device for keeping liq-mold. { er sist formi } uids and solids in liquids in motion by mixing,air-atomizing oil burner [ENG] An oil burner instirring, or shaking. { aj tadr } which a stream of fuel oil is broken into very fineagitator body [MECH ENG] A truck-mounted droplets through the action of compressed air.drum for transporting freshly mixed concrete;{ er at mzi oil brnr } rotation of internal paddles or of the drum pre- air bag [MECH ENG] An automotive vehicle pas-vents the setting of the mixture prior to delivery.senger safety device consisting of a passive re-{ aj tadr bade } straint in the form of a bag which is automatically12 24. air conditionerinflated with gas to provide cushioned protec- air cap [MECH ENG] A device used in thermaltion against the impact of a collision. { er spraying which directs the air pattern for pur- bag } poses of atomization. { er kap }air belt [MECH ENG] The chamber which equal- air casing [ENG] A metal casing surrounding aizes the pressure that is blasted into the cupolapipe or reservoir and having a space between toat the tuyeres. { er belt }prevent heat transmission. { er kasi }air bind [ENG] The presence of air in a conduitair cell [ELECTR] A cell in which depolarizationor pump which impedes passage of the liquid. at the positive electrode is accomplished chemi-{ er bnd }cally by reduction of the oxygen in the air.airblasting [ENG] A blasting technique in which[MECH ENG] A small auxiliary combustionair at very high pressure is piped to a steel shellchamber used to promote turbulence and im-in a shot hole and discharged. Also known as prove combustion in certain types of diesel en-air breaking. { er blasti }gines. { er sel }air bleeder [MECH ENG] A device, such as a nee-air chamber [MECH ENG] A pressure vessel,dle valve, for removing air from a hydraulic sys-partially filled with air, for converting pulsatingtem. { er bledr }flow to steady flow of water in a pipeline, as withairborne collision warning system [ENG] A sys- a reciprocating pump. { er chambr } tem such as a radar set or radio receiver carriedair change [ENG] A measure of the movementby an aircraft to warn of the danger of possible of a given volume of air in or out of a buildingcollision. { er born k lizhn worni sis or room in a specified time period; usually ex-tm }pressed in cubic feet per minute. { er chanj }airborne detector [ENG] A device, transportedair check [ENG ACOUS] A recording made of aby an aircraft, whose function is to locate or live radio broadcast for filing purposes at theidentify an air or surface object. { er born di broadcasting facility. { er chek } tektr } air classifier [MECH ENG] A device to separateairborne electronic survey control [ENG] The particles by size through the action of a streamairborne portion of very accurate positioning sys- of air. Also known as air elutriator. { er klastems used in controlling surveys from aircraft. fr }{ er born i lek tranik srva kn trol } air cleaner [ENG] Any of various devices de-airborne intercept radar [ENG] Airborne radar signed to remove particles and aerosols of spe-used to track and lock on to another aircraft cific sizes from air; examples are screens, settlingto be intercepted or followed. { er born inchambers, filters, wet collectors, and electro-tr sept ra dar } static precipitators. { er klenr }airborne magnetometer [ENG] An airborne in- Airco-Hoover sweetening [CHEM ENG] Remo-strument used to measure the magnetic field of val of mercaptans from gasoline by caustic andthe earth. { er born magn tamdr } water washes, then heating the dried gasolineairborne profile recorder [ENG] An electronic and passing it with some oxygen through a reac-instrument that emits a pulsed-type radar signalfrom an aircraft to measure vertical distances tor containing a slurry of diatomaceous earthbetween the aircraft and the earths surface.impregnated with copper chloride; the oxygenAbbreviated APR. Also known as terrain profile regenerates the catalyst. { er ko huvrrecorder (TPR). { er born pro fl ri kordr } swetni }airborne radar [ENG] Radar equipment carried air compressor [MECH ENG] A machine that in-by aircraft to assist in navigation by pilotage, tocreases the pressure of air by increasing its den-determine drift, and to locate weather distur- sity and delivering the fluid against the con-bances; a very important use is locating other nected system resistance on the discharge side.aircraft either for avoidance or attack. { er{ er km presr } born ra dar } air-compressor unloader [MECH ENG] A deviceairborne waste [ENG] Vapors, gases, or particu-for control of air volume flowing through an airlates introduced into the atmosphere by evapo- compressor. { er km presr n lodr } ration, chemical, or combustion processes; a fre-air-compressor valve [MECH ENG] A device forquent cause of smog and an irritant to eyes andcontrolling the flow into or out of the cylinderbreathing passages. { er born wast } of a compressor. { er km presr valv }air-bound [ENG] Of a pipe or apparatus, con- air condenser [MECH ENG] 1. A steam con-taining a pocket of air that prevents or reduces denser in which the heat exchange occursthe desired liquid flow. { er baund } through metal walls separating the steam fromair brake [MECH ENG] An energy-conversioncooling air. Also known as air-cooled con-mechanism activated by air pressure and used denser. 2. A device that removes vapors, suchto retard, stop, or hold a vehicle or, generally,as of oil or water, from the airstream in a com-any moving element. { er brak } pressed-air line. { er kn densr }air breaking See airblasting. { er braki }air conditioner [MECH ENG] A mechanism pri-air-breathing [MECH ENG] Of an engine or aero- marily for comfort cooling that lowers the tem-dynamic vehicle, required to take in air for the perature and reduces the humidity of air in build-purpose of combustion. { er brethi } ings. { er kn dishnr }13 25. air conditioningair conditioning[MECH ENG] The maintenancedeflecting vanes discharging supply air in variousof certain aspects of the environment within adirections and planes, and arranged to promotedefined space to facilitate the function of thatmixing of the supplied air with the air alreadyspace; aspects controlled include air tempera- in the room. { er di fyuzr }ture and motion, radiant heat level, moisture,air-distributing acoustical ceiling [BUILD] Aand concentration of pollutants such as dust, suspended acoustical ceiling in which the boardmicroorganisms, and gases. Also known as cli- or tile is provided with small, evenly distributedmate control. { er kn dishni } mechanical perforations; designed to provide aair conveyor See pneumatic conveyor. { er desired flow of air from a pressurized plenumkn var } above. { er di stribydi kustikl seli } air-cooled engine [MECH ENG] An engineair diving [ENG] A type of diving in which thecooled directly by a stream of air without thedivers breathing medium is a normal atmos-interposition of a liquid medium. { er kuldpheric mixture of oxygen and nitrogen; limited enjn } to depths of 190 feet (58 meters). { er dvi }air-cooled heat exchanger [MECH ENG] Aair drain [CIV ENG] An empty space left aroundfinned-tube (extended-surface) heat exchanger the external foundation wall of a building towith hot fluids inside the tubes, and cooling prevent the earth from lying against it and caus-air that is fan-blown (forced draft) or fan-pulleding dampness. { er dran } (induced draft) across the tube bank. { er kuldairdraulic [MECH ENG] Combining pneumatic het iks chanjr } and hydraulic action for operation. { er drolair cooling [MECH ENG] Lowering of air temper-ik }ature for comfort, process control, or food preser- air drill [MECH ENG] A drill powered by com-vation. { er kuli } pressed air. { er dril }air course See airway. { er kors } air drying [ENG] Removing moisture from a ma-aircraft detection [ENG] The sensing and dis- terial by exposure to air to the extent that nocovery of the presence of aircraft; major tech- further moisture is released on contact with air;niques include radar, acoustical, and optical important in lumber manufacture. { er dri } methods. { er kraft di tekshn } air duct See airflow duct. { er dkt }aircraft impactor [ENG] An instrument carried air ejector [MECH ENG] A device that uses aby an aircraft for the purpose of obtaining sam-fluid jet to remove air or other gases, as from aples of airborne particles. { er kraft im paksteam condenser. { er i jektr }tr } air eliminator [MECH ENG] In a piping system,air-cure [CHEM ENG] To vulcanize at ordinarya device used to remove air from water, steam,room temperatures, or without the aid of heat.or refrigerant. { er i lim nadr }{ er kyur }air elutriator See air classifier. { er e lutre adr } air curtain [MECH ENG] A stream of high-veloc-air engine [MECH ENG] An engine in whichity temperature-controlled air which is directedcompressed air is the actuating fluid. { erdownward across an opening; it excludes insects, enjn }exterior drafts, and so forth, prevents the transferair entrainment [ENG] The inclusion of minuteof heat across it, and permits air-conditioning bubbles of air in cement or concrete through theof a space with an open entrance. { er krtn }addition of some material during grinding orair cushion [MECH ENG] A mechanical devicemixing to reduce the surface tension of the water,using trapped air to arrest motion without shock. giving improved properties for the end product.{ er kushn } { er in tranmnt } air-cushion vehicle [MECH ENG] A transporta-air escape [DES ENG] A device that is fitted totion device supported by low-pressure, low- a pipe carrying a liquid for releasing excess air;velocity air capable of traveling equally well over it contains a valve that controls air release whilewater, ice, marsh, or relatively level land. Also preventing loss of liquid. { er skap }known as ground-effect machine (GEM); hover-air-exhaust ventilator [MECH ENG] Any air-craft. { er kushn vekl }exhaust unit used to carry away dirt particles,air-cut [ENG] Referring to the inadvertent me-odors, or fumes. { er ig zost vent ladr } chanical incorporation of air into a liquid system. airfield [CIV ENG] The area of an airport for the{ er kt }takeoff and landing of airplanes. { er feld } air cycle [MECH ENG] A refrigeration cycle char-air filter [ENG] A device that reduces the con-acterized by the working fluid, air, remaining as centration of solid particles in an airstream to aa gas throughout the cycle rather than beinglevel that can be tolerated in a process or spacecondensed to a liquid; used primarily in airplane occupancy; a component of most systems inair conditioning. { er skl } which air is used for industrial processes, ventila-air cylinder [MECH ENG] A cylinder in which air tion, or comfort air conditioning. { er filtr }is compressed by a piston, compressed air isair flotation See dissolved air flotation. { erstored, or air drives a piston. { er silndr } flo tashn } air density [MECH] The mass per unit volume airflow duct [ENG] A pipe, tube, or channelof air. { er densde } through which air moves into or out of an en-air diffuser [BUILD] An air distribution outlet,closed space. Also known as air duct. { erusually located in the ceiling and consisting of flo dkt } 14 26. air lockairflow orifice [ENG] An opening through whichair hp See air horsepower.air moves out of an enclosed space. { er flo air-injection reactor [MECH ENG] A unit in- orfs } stalled in an automotive engine which mixesairflow pipe [ENG] A tube through which air isfresh air with hot exhaust gases in the exhaustconveyed from one location to another. { er manifold to react with any gasoline that has flo pp } escaped unburned from the cylinders. Abbrevi-air-fuel mixture [MECH ENG] In a carbureted ated AIR. { er injekshn re aktr }gasoline engine, the charge of air and fuel thatair-injection system [MECH ENG] A device thatis mixed in the appropriate ratio in the carbure- uses compressed air to inject the fuel into thetor and subsequently fed into the combustioncylinder of an internal combustion engine.chamber. { er fyul mikschr }Also known as thermactor. { er injekshnair gage [ENG] 1. A device that measures air sistm }pressure. 2. A device that compares the shape air inlet [MECH ENG] In an air-conditioning sys-of a machined surface to that of a reference sur- tem, a device through which air is exhaustedface by measuring the rate of passage of air be-from a room or building. { er in let }tween the surfaces. { er gaj } air-inlet valve [MECH ENG] In a heating/air-con-air gap [ELECTR] 1. A gap or an equivalent filler ditioning system of a motor vehicle, a valve inof nonmagnetic material across the core of athe plenum blower assembly that permits selec-choke, transformer, or other magnetic device. tion of either inside or outside air. { er in let2. A spark gap consisting of two electrodes sepa-valv }rated by air. 3. The space between the stator air knife [ENG] A device that uses a thin, flat jetand rotor in a motor or generator. [ENG]of air to remove the excess coating from freshly1. The distance between two components or coated paper. { er nf }parts. 2. In plastic extrusion coating, the dis-air-knife coating [ENG] An even film of coatingtance from the opening of the extrusion die toleft on paper after treatment with an air knife.the nip formed by the pressure and chill rolls. { er nf kodi } 3. The unobstructed vertical distance between air-lance [ENG] To direct a pressurized-airthe lowest opening of a faucet (or the like) whichstream to remove unwanted accumulations, assupplies a plumbing fixture (such as a tank orin boiler-wall cleaning. { er lans }washbowl) and the level at which the fixture will air leakage [MECH ENG] 1. In ductwork, airoverflow. { er gap }which escapes from a joint, coupling, and such.air grating [BUILD] A fixed metal grille on the 2. The undesired leakage or uncontrolled pas-exterior of a building through which air is sage of air from a ventilation system. { erbrought into or discharged from the building for lekj } purposes of ventilation. { er gradi } airless spraying [ENG] The spraying of paint byair hammer See pneumatic hammer. { er hammeans of high fluid pressure and special equip-r }ment. Also known as hydraulic spraying.air-handling sys