Engineering Dictionary for All Engineering Disciplines

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<ul><li><p>8/10/2019 Engineering Dictionary for All Engineering Disciplines</p><p> 1/53</p><p>Engineering DictionaryFor all Engineering Disciplines</p><p> A ABMA</p><p>- American Boiler Manufacturers Associ ation. ABRASION</p><p>- The w earing aw ay of a surface by rubbing, as w ith sandpaper on w ood.</p><p> ABRASION RESISTANCE- The ability of a material to resis t surface w ear.</p><p> ABRASIV E EROSI ON- Erosiv e w ear caused by the relativ e motion of solid particles w hich are entrained in a fluid, mov ing nearly parallel to a solid surface.</p><p> ABSOL UTE HUMIDITY- Amount of moisture in the air, indic ated in kg/kg of dry air.</p><p> ABSOL UTE PRESSURE- Total pressure measured from an absolute v acuum. It equals the sum of the gauge pressure and the atmospheric press ure corresponding to the</p><p>barometer.</p><p> ABSOL UTE PRESSURE- Air at standard conditions (70F air at sea l ev el w ith a barometric press ure of 29.92 in Hg) exerts a pres sure of 14.696 psi. This i s the press ure in a</p><p>system w hen the pressure gauge reads zero. So the absolute pressure of a system is the gauge pressure in pounds per s quare inch added to theatmospheric pressure of 14.696 psi (use 14.7 psi in env ironmental system work) and the symbol is " psia" .</p><p> ABSOLUTE TEMPERATURE SCALE</p><p>- A scale of temperature measurement in whi ch zero degrees is absolute zero.</p><p> ABSOL UTE VELOCITY -</p><p> ABSOL UTE ZERO- A hypothetical temperature at w hich there is total absence of heat. Since heat is a result of energy caused by molecular motion, there is no motion of</p><p>molecules w ith respect to each other at absolute zero. It is theoretically the coldest possible temperature.</p><p> ABSOLUTE ZERO TEMPE RATURE- Temperature measur ed from absol ute zero (-459.67F, or -273.16C).</p><p> ABSORBENT- A material w hich, due to an affinity for certain substances, extracts one or more such s ubstances from a liquid or gaseous medium w ith w hich it</p><p>contacts and whic h changes physically or chemically, or both, during the process. Calcium chloride is an example of a solid absorbent, whil e solutionsof lithium chloride, li thium bromide, and ethylene glycols are liquid absorbents.</p><p> ABSORBER- That part of the low side of an absorption system, used for absorbing v apor refrigerant.</p><p> ABSORPTION- A process w hereby a material extracts one or more s ubstances present in an atmosphere or mixture of gases or li quids accompanied by the material's</p><p>physical and/or chemical changes.</p><p> ABSORPTION REFRIGERATION SYSTEM- One in whic h the refrigerant, as it is abs orbed in another liquid, maintains the pressure difference needed for succes sful operation of the system.</p><p> ABSORPTION REFRIGERATOR- Refrigerator that creates low temperatures by using the c ooling effect formed when a refrigerant is absorbed by chemical s ubstance.</p><p> ABSORPTION SYS TEM</p><p>- A refrigeration system in w hich the refrigerant gas ev olv ed in the evaporator is taken up in an absorber and released in a generator upon the</p><p>application of heat.</p><p> ABSORPTION TOWER- A tow er or column, w hich effects contact between a ris ing gas and a falling liquid, so that part of the gas may be taken up by the liquid.</p><p> ACCELERATION- The rate of change of v elocity, as a function of time. Expressed in m/s.</p><p>4/19/2011 Engineering Dictionary For all Engine</p><p>orcad.com/engineering-dictionary.html 1/53</p></li><li><p>8/10/2019 Engineering Dictionary for All Engineering Disciplines</p><p> 2/53</p><p> - The rate of increase in v elocity of a body falling freely in a v acuum. Its v alue v aries w ith latitude and elevation. The International Standard is 32.174 ft.</p><p>per second per second.</p><p> ACCELERATION PERIOD- In cavi tation and liquid impingement erosion, the stage following the incubation period, during w hich the erosion r ate increases from near zero to a</p><p>maximum value.</p><p> ACCELERATION- The time rate of change of v elocity; i.e., the deriv ative of v elocity; with res pect to time.</p><p> ACCEPTABLE WELD- A weld that meets all of the requirements and the acceptance criteria presc ribed by the welding specific ations.</p><p> ACCESSIBLE HERM ETIC- An assembly of motor and compressor, insi de a si ngle bolted housing unit.</p><p> ACCUMULATOR- Storage tank w hich receiv es liquid refrigerant from evaporator and prev ents it from flowing into suction line before vaporizing.</p><p> ACETONE- A filler added to acetylene cylinders, capable of absorbing 25 times its ow n v olume of acetylene.</p><p> ACID- Literally hitter, but chemical ly the state of a w ater solution containing a high concentration of hydrogen ions.</p><p> ACID ATTACK- Caused by an incomplete flushing after an acid c leaning process of boilers or simil ar equipment.</p><p> ACID CLEANING- The process of cleaning the interior surfaces of steam generating units by filling the unit with dil ute acid acc ompanied by an inhibitor to prevent</p><p>corrosion and by subsequently draining, w ashing, and neutralizing the acid by a further was h of alkaline w ater.</p><p> ACID CONDITION IN SYSTEM- Condition in w hich refrigerant or oil in a system, is mixed w ith v apor and fluids that are acidic in nature.</p><p> ACID EMB RITTLEM ENT- A form of hydrogen embrittlement that may be induced in some metals by an acid.</p><p> ACID GAS- A gas that forms an acid w hen mixed w ith w ater. In petroleum processing, the most common acid gases are hydrogen sulfide and carbon dioxide.</p><p> ACID RAIN- Atmospheric prec ipitation with an pH below 5.6 to 5.7.</p><p> ACID SOAK- A method of acid c leaning, in w hich the acid is pumped into the boiler and rests there for a period of time.</p><p> ACIDIC- The reaction of a substance w ith w ater resulting in an inc rease in c oncentration of hydrogen ions in solution (see acid).</p><p> ACIDIFIED- The addition of an acid (usually nitric or sulfuric ) to a sample to low er the pH below 2.0. The purpose of the acidification is to "fix " a sample so it w ill</p><p>not change until it i s analyzed.</p><p> ACIDITY- Represents the amount of free carbon dioxi de, mineral acids, and salts (especially sulfates of iron and aluminum) which hydrolyze to give hydrogen</p><p>ions in the water. The acidity is reported as Millie equiv alents per liter of aci d, or ppm acidity as c alcium carbonate, or pH, the measure of hydrogen ionconcentration.</p><p> ACOUSTIC</p><p>- A term pertaining to sound, or the science of sound.</p><p> ACROSS THE LINE- A method of motor starting, whic h connects the motor directly to the supply line on s tarting or running.</p><p> ACTION- Refers to the action of a controller. It defines what is done to regulate the final control element to effect control.</p><p> ACTIVATED ALUMINA- Chemical w hich is a form of aluminum oxide. It is used as a drier or desicc ant.</p><p> ACTIVATED CARBON- Is a specially process ed carbon, used as a filter drier. Commonly used to clean air.</p><p> ACTIVATED SLUDGE- An aerobic biological process for conv ersion of soluble organic matter to solid biomass , remov able by grav ity or filtration.</p><p> ACTIVE STORAGE PILE- A method of stockpiling c oal, sometimes called li v e storage. The pile is located outside the plant but adjacent to it, and usually contains four or five</p><p>days of operating supply. The pile is not compacted, as it is not stored long enough to be exposed to the hazard of spontaneous combustion.</p><p> ACTUATOR- The portion of a regulating v alv e, whic h conv erts mechanical, fluid, thermal, or electrical energy; into mechanical motion to open or close the v alv e</p><p>seats or other such devices.</p><p>4/19/2011 Engineering Dictionary For all Engine</p><p>orcad.com/engineering-dictionary.html 2/53</p></li><li><p>8/10/2019 Engineering Dictionary for All Engineering Disciplines</p><p> 3/53</p><p> ADIABATIC- Occurring w ith no addition or loss of heat from the system under consi deration.</p><p> ADIABATIC CHANGE- A change in the v olume, pressure, or temperature of a gas, occurring w ithout a gain of heat or loss of heat.</p><p> ADIABATIC COMPRESSION- Compressing a gas w ithout removing or adding heat.</p><p> ADIABATIC COOLING- A method in w hich paramagnetic s alts are pre-cooled, and then demagnetized, thereby producing further cooling.</p><p> ADIABATIC EFFICIENCY-The ratio of actual w ork output of a heat engine to the ideal output.</p><p> ADIABATIC EXPA NSION- The expansion of a gas, v apor, or liquid stream from a higher pressure to a low er pressure, w ith no change in enthalpy.</p><p> ADIABATIC PROCESS- A thermo-dynamic proces s in w hich no heat is extracted from or added to the system of the process.</p><p> ADIABATIC SATURATION PROCESS- A process to determine absolute or relativ e humidity.</p><p> ADJUSTABLE DIFFERENTIAL- A means of changing the difference between the control cut-in and cutout points.</p><p> ADJUSTABLE RESISTOR</p><p>- A resistor w hose v alue can be mechanically changed, usually by the use of a sliding c ontact.</p><p> ADSORBENT- A material w hich has the ability to cause molecules of gases, liquids or s olids to adhere to its internal surfaces w ithout changing the adsorbent</p><p>physically or chemic ally. In water treatment, a synthetic resin possess ing the ability to attract and to hold charged particles .</p><p> ADSORPTION- The adhesion of the molecules of gases , dissolv ed substances, or liquids in more or less concentrated form, to the surface of solids or liquids w ith</p><p>w hich they are in contact. Commercial adsorbent materials hav e enormous internal surfaces.</p><p> ADSORPTION INHIBITORS- They are materials w hich c aused them to be adsorbed on to the metal surface due to their polar properties.</p><p> ADVECTION- The transfer of heat by horizontal mov ement of air.</p><p> AERATION - Exp os ing to the ac tio n o f ai r, li ke blow ing ai r through w ater befo re di sc har ging to a ri v er .</p><p> AERATION CELL- (see oxygen cell)</p><p> AEROBIC- A condition in which " free" or dissolv ed oxygen is present in water.</p><p> AERODYNAMIC NOISE- Also called generated noise, self-generated noise; is noise of aerodynamic origin in a mov ing fluid arising from flow instabilities. In duct systems,</p><p>aerodynamic noise is caused by airflow through elbows, dampers, branch w yes, pressure reduction devices , silencers and other duct components.</p><p> AGGLOMERATE- The clustering together of a few or many particles into a larger solid mas s.</p><p> AGITATOR- A dev ice used to cause motion in confined fluids.</p><p> AIR- A substance c ontaining by volume approximately 78 - 79% nitrogen; 20.95% oxygen, .94% argon, traces of c arbon dioxide, helium, etc.</p><p> AIR BLAST TRANSFORMER- A transformer cooled by forcing a circulation of air around its w indings.</p><p> AIR CAPACITOR- Is a capacitor, w hich uses air as the dielectric between the plates.</p><p> AIR CHANGES- A method of expressing the amount of air leakage into or out of a building or room in terms of the number of building v olumes or room v olumes</p><p>exchanged.</p><p> AIR CLEANER- A devi se used to remove air borne impurities.</p><p> AIR COIL- Coil on s ome types of heat pumps used ei ther as an ev aporator or a condenser.</p><p> AIR CONDITIONER- They are basically refrigeration devi ces c ooling air and rooms rather then food compartments.</p><p>4/19/2011 Engineering Dictionary For all Engine</p><p>orcad.com/engineering-dictionary.html 3/53</p></li><li><p>8/10/2019 Engineering Dictionary for All Engineering Disciplines</p><p> 4/53</p><p> AIR CONDITIONER, UNITARY- An evaporator, compressor, and c ondenser combination; designed in one or more ass emblies, the separate parts designed to be assembled together.</p><p> AIR CONDITIONING-The process of treating air to si multaneously control its temperature, humidity, cleanliness , and distribution to meet the requirements of the c onditioned</p><p>space.</p><p> AIR CONDITIONING UNIT- An assembly of equipment for the treatment of air so as to control, simultaneously, its temperature, humidity, cleanliness and distribution to meet the</p><p>requirements of a conditioned space.</p><p> AIR CONDITIONING, COMFORT- The process of treating air so as to c ontrol simultaneously its temperature, humidity, cleanliness and distribution to meet the comfort requirements of</p><p>the occupants of the conditioned space.</p><p> AIR COOLER- A factory-encased ass embly of elements whereby the temperature of air pass ing through the devic e is reduced.</p><p> AIR DIFFUSER- A circular, s quare, or rectangular air distribution outlet, generally located in the ceil ing and compris ed of deflecting members disc harging supply air in</p><p>v arious directions and planes, and arranged to promote mixing of primary air w ith secondary room air.</p><p> AIR DIFFUSION AERATORS- They are aerators into which air is pumped into the water through perforated pipes, plates, or any other method.</p><p> AIR DUCT- A tube or conduit for conv eying air from one place to another.</p><p> AIR FLOTATION- A process of acc elerating sedimentation, by introducing air into the w ater, this low ers the density of the water, and increases the differences i n the</p><p>densities of the w ater and the suspended particles. (DAF), Dissolv ed Air Flotation.</p><p> AIR GAP-The space between magnetic poles , or betw een the rotating and stationary assemblies i n a motor or generator.</p><p> AIR HANDLER- The fan blower, heat transfer coil, filter, and housing parts, of a system.</p><p> AIR INFILTRATION The l eak age of a ir in to a room throug h c rack s in doo rs , w indow s, and other ope nings .</p><p> AIR PURGE- The remov al of undesired matter by replacement with air .</p><p> AIR SATURATED</p><p>- Moist air in w hich the partial pressure of the water v apor is equal to the v apor pressure of w ater at the existing temperature. This occ urs w hen dry airand saturated water v apor coexis t at the same dry-bulb temperature.</p><p> AIR SENSING THERMOSTAT- A thermostat unit, in w hich the sensi ng element is loc ated in the refrigerated space.</p><p> AIR STANDARD- Air hav ing a temperature of (20C), a relativ e humidi ty of 36 percent, and under a pres sure of 14.70 PSIA. The gas indus try usually con sider s (16C) as</p><p>the temperature of standard air.</p><p> AIR VENT- Valv e, either manual or automatic, to remove air from the highest point of a coil or piping as sembly.</p><p> AIR WASHER- A water spray system or dev ice for c leaning, humidifying, or dehumidifying the air.</p><p> AIR, AM BIENT- Generally the air s urrounding the objec t.</p><p> AIR, DRY- Air w ithout contained water v apor.</p><p> AIR, OUTDOOR- Air taken from outdoors and, therefore, not previousl y circ ulated through the system.</p><p> AIR, RECIRCULATED- Return air pass ed through the conditioner before being again supplied to the c onditioned space.</p><p> AIR, REHEATING- In an air conditioning system, the final step in treatment, in the ev ent the temperature is too low .</p><p> AIR, RETURN- Air returned from conditioned or refrigerated space.</p><p> AIRBORNE SOUND- Sound w hich reaches the point of interest by radiation through the air.</p><p> AIR-COOLED CONDENSER- Hea t o f c om r es si on i s tr ans fer red fr om c onden si n c oi ls to s ur rou nd in ai r. Th is m a b e d on e e i ther b c onv e cti on or b a fan o r bl ow e r.</p><p>4/19/2011 Engineering Dictionary For all Engine</p><p>orcad.com/engineering-dictionary.html 4/53</p></li><li><p>8/10/2019 Engineering Dictionary for All Engineering Disciplines</p><p> 5/53</p></li><li><p>8/10/2019 Engineering Dictionary for All Engineering Disciplines</p><p> 6/53</p><p> AMPACITY - A w ir e's abi li ty to ca rr y cur ren t s afe ly, w ith out und ue h eati ng. The t erm fo rm er ly u se d to des cr ib e th is ch arac ter is ti c w as cu rr ent ca pac ity of t...</p></li></ul>