M. Ibbotson - Professional english in use engineering (794233), страница 29
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The bottom end may also be immersed, although this is notnecessary. When the flow begins, the liquid in the hose must run at full bore- that is, thebore of the hose (its inside diameter) must be completely filled with water, with no air in it.Siphonic action is often used to drain rainwater from the roofs of large buildings. Unlikenormal rainwater pipes, the pipes of siphonic drainage systems are designed to run at fullbore, which allows them to flow much faster.
This means smaller-diameter pipes can be used.These take up less space in the building.higher-level tankA siphonI I2Professional English in Use Engineeringlower-level tankManaging rotary motionThe following mechanisms are often used in machines that have rotating shafts and wheels.MechanismNotesa bearing•••allows a shaft, such as a driveshaft or an axle (a shaft to which avehicle's wheels are fixed) to revolve inside a hole•allows drive to be transmitted progressively (by friction), from aconstantly revolving driveshaft, to wheels that are not yet revolving••••may be operated manually, or may be an automatically operatedcentrifugal clutcha universal jointa clutchbrakesmay require a lubricant- oil or grease- to help reduce frictionused to connect the ends of two shafts that are at an angle to eachother, allowing drive to be transmitted, through the angle, between thetwo shaftsused to slow down and stop rotary motion, usually by frictionin disc brakes, a pair of brake pads is pressed against the sides of ametal brake disc which is fixed to the shaftin drum brakes, brake pads are pressed against the inside of a hollowcylinder, called a drumA universal jointProfessional English in Use Engineering113EIJ Electrical and electronic componentsCommon components and their functions114ComponentFunctionamplifieramplifies an electric current- that is, increases the amplitude (waveheight) of the currentantennareceives or transmits (sends) radio signalsbatteryseveral cells connected togethercapacitorconsists of two conductors which are separated by a dielectric(insulating) material- allows a certain amount of electrical charge tobe storedcellan electrical storage device, containing chemicals, which supplies adirect currentcircuit-breakera safety device which automatically switches off a circuitdiodea device with two terminals which allows current to flow in onedirection onlyfusea thin conductor which burns and breaks at a certain amperage, toprotect a circuitinductora coil which is used to produce electromagnetic inductioninverterconverts direct current to alternating currentlampproduces light - often an incandescent lamp, which consists of afilament inside a glass bulbpotentiometera variable resistor with three connectionsrectifierconverts alternating current to direct currentrelaya switch which is operated electrically (not mechanically)resistorproduces a precise amount of resistancerheostata variable resistor with two terminalsspeaker I loudspeakerconverts electrical energy to sound energyswitchallows electric current to flow when closed (switched on), and stopscurrent flowing when opened (switched off)transformera step-up transformer increases voltage and reduces amperage, and astep-down transformer reduces voltage and increases amperagetransistora device with three terminals which can be used as an amplifier orswitchProfessional English in Use EngineeringComponents and symbolsComponentSymbolammeter-®-ComponentSchottky diodeSymbol+amplifier--{>--tunnel diode~antennarZener diode~"')battery-111tcapacitorsIfuseinductorsfixed capacitor--)~air-core inductorfeed-through capacitor-il~bifilar inductorpolarized capacitor-JF-iron-core inductorvariable capacitorcellcircuit-breaker*---i~(\--TdiodesGunn diodelight-emitting diode (LED)PIN diodephotodiode~I ""~II~~---~~variable inductor~--6-lampmicrophonemotor~~~tapped inductor~delay lineIohmmeteroscilloscopepiezoelectric crystalD=--®---®--e--l0f-~(¥Professional English in Use EngineeringI I5ComponentSymbolresistorsComponentrotary switch-AM-fixed resistor~=Q]variable resistor (rheostat)speaker I loudspeakerair-core transformeriron-core transformersingle pole, single throw(SPST) switch~o--bipolar NPN (negative,positive, negative) transistorsingle pole, double throw(SPDT) switch~bipolar PNP (positive,negative, positive) transistordouble pole, single throw(DPST) switch~o--field-effect N-channel(negative channel) transistordouble pole, double throw(DPDT) switch~field-effect P-channel(positive channel) transistoro--~o-~momentary contact switch,normally open (NO) Ipush-to-make switch--omomentary contact switch,normally closed (NC) Ipush-to-break switch--o__l__o--ID--MOS (metal oxidesemiconductor) field-effectN-channel transistorMOS field-effect P-channeltransistorvoltmeterwattmeterI I6Professional English in Use Engineeringo0 o0 0.00 0 0transformerstransistorsswitchesSymbol][Jll[-©-©~~-e-@-@-®-®-Logic gatesLogic gates are electronic devices generally made from transistors and diodes.
All types oflogic gate, except NOT gates (see below), have two input terminals. The input terminalsreceive signals in the form of voltages, and are designed to simply detect whether there is avoltage (considered to be the signal '1 ' ), or not (considered to be the signal '0') .All logic gates have one output terminal, which can send the signal 1 (a voltage) or the signal0 (no voltage). Whether the logic gate sends a 1 or a 0 depends on the combination of signalsreceived by the input terminals, and on the type of logic gate being used.
The different typesof logic gate are shown below.AND gate==t=)--NOT gate, or inverterInput 1 Input 2 Output000010100111Input 1 Input 2The outputsignal is 1only if bothinput signalsare 1.ORgate~Input 1 Input 2 Output000011101111NAND gate==C)--Input 1 Input 2Output~1001XOR gateThe outputsignal is 1 if(a) either oneof the inputsignals is 1,or if (b) bothinput signalsare 1.NOR gateThe gate only hasone input point. Theoutput signal is theopposite of the inputsignal.=}D--Input 1 Input 2000011101110=C>-Input 1 Input 2OutputThe outputsignal is 1 ifeither of theinput signalsis 1, but is 0if both inputsignals are 1.OutputXNOR gate=}D-Input 1 Input 2 Output001001001011010010101100100110110111A NAND gate is the oppositeof an AND gate, functioning asan AND gate + a NOT gate.A NOR gate is the oppositeof an OR gate, functioningas an OR gate+ a NOT gate.An XNOR gate is theopposite of an XOR gate,functioning as an XOR gate+a NOT gate.Professional English in Use EngineeringI I7EmJ Sensing, measuring and regulating devicesDeviceFunctionvoltmeterdetects and measures voltageammeterdetects and measures electric currentohmmeterdetects and measures electrical resistancethermostatregulates temperature- switches a heating or cooling system on or offat a set temperaturethermocouplemeasures or controls temperature - produces a voltage which variesproportionally as the temperature difference between two points variesthermistormeasures or controls temperature- produces a resistance which variesproportionally as temperature varies (thermistor is short for 'thermalresistor')photosensora general term for devices that detect and measure lightproximity sensormeasures the distance between itself and nearby objectspiezoelectric sensormeasures movement and strain- produces an electric current whenstressed mechanicallyflowmetermeasures the rate of flow of a fluidbarometermeasures atmospheric pressurehygrometermeasures the amount of moisture (water vapour) in the airaltimetermeasures altitude, usually as a height above sea levelsmoke detectordetects smoke, usually to provide a fire warningaccelerometermeasures acceleration and deceleration forcesmotion detectordetects movement- usually of people- that are a certain distance awaymicrophonedetects soundA smoke detectorA digital multi meter can measureamperage and voltage.118Professional English in Use EngineeringAnswer key1.
1actual size2 scale1.21f, 2b, 3a, 4e, 5d, 6c1.31 general arrangement2 computer-aided design1.4section2 GA2.1design brief2 sketch2.23 general arrangement4 schematics5 set6 CAD3 drawing4 three-dimensional5 cross-section3 plan4 elevationamend, redesign, refine, revise1 draft2 current2.4issued2 revision3.13 notes4 amendments5 draft6 superseded1 determined1 allow for4.1overall2 span4.27 current8 work3 function, designed, feature4 existing, proposedconstraint, budget, exceed2 factor of safety3 approve, sign off4 supersede5 working4 overdesigned5 belt and braces6 Sizing2 worst-case scenarios3 factored in3.37 scale8 detail6 schematic3 work4 comment2 cost-effective3.25 3D3 preliminary drawing4 concept2 circulate, issue2.36 one to fifty3 overdesigning4 quantify5 worst-case scenarios6 cost-effective3 height4 width5 thicknessfalse - The height of the towers is measured vertically.false- The overall span is measured along the length of the bridge.truetruefalse -The thickness of each tower decreases towards the top, so the faces of the towersare out of plumb.6 false -The greatest thickness of each tower is its external thickness at its base.23454.32 plumb3 inclined4 out of plumb5 length6 height4.4 The towers are plumb, but because they area long distance a part, the curvature of theearth (the curve of the earth's surface) has anoticeable effect, which is increased by theheight of the towers.
The diagram belowshows the effect in exaggerated form.Professional English in Use Engineering1195.15 locate1 at 175 mm centres2 centreline4 at a right-angle I at right-angles5.2gridline2 set out3 parallel4 intersect5.31b, 2a, 3d, 4c6.1circular2 radius3 diameter4 circumference5 constant7 deformed8 curved6 arc9 chord6.2the crown2 the invert3 the outside diameter4 the inside diameter I the bore6.31 The distance travelled by the vehicle each time its wheels turn completely is equal to thecircumference of one of its tyres.2 The radius of the tyre is measured from the centre of the wheel to the outside edge of thetyre.3 The radius of the curve in the motorway is constant, so the edges of the road follow arcsof a circle.4 The curve in the motorway has a constant radius, so the inside and outside edges of theroad are arcs of two concentric circles that have the same centre.5 The crown is on the circumference of the external face of the pipe, and therefore cannot bein contact with the liquid flowing inside the pipe.6 The thickness of the wall at the bottom of the pipe, plus the distance between the invertand the crown of the pipe, is equal to the outside diameter of the pipe.7.1permissible2 accurate I precise3 vary I deviate4 precision I accuracy5 imprecise I inaccurate7.21 b, 2f, 3e, 4c, 5a, 6d7.3variation2 prectse8.18.28.33 offset6 variation I range7 within tolerance8 outside tolerance9 tight tolerance I close tolerance10 loose tolerance3 tolerances5 minus4 plus6 within9 fit10 clearances4 zero, nought1 fraction2 rounded up, decimal places3 rounded down, decimal place3 multiplied4 divided8.4sum2 square, multiplied by I times3 multiplied by I times, divided by9.11 density2 cross-sectional area1207 permissible8 range3 a/one thousandth of aone point seven nine three2 a/one hundredth of a1 plus2 times5 perpendicular6 square off4 whole5 negligible6 rounding error5 sum6 square3 volume4 massProfessional English in Use Engineering7 subtract8 square root9 squared10 less I minus4 square root5 equal5 surface area9.29.310.110.210.311.1metres2 millimetres3 square millimetres4 square metres5 cubic metres6 kilograms7 kilograms per cubic metrecubic2 mass3 gravity5 lightweight4 weigh6 weightlessconsumption2 consume3 average4 duration5 constant7 cumulative6 rate8 capacity11,72 43 77 square4 95 2output, supply, efficient2 surplus, peak3 gamnon-metal3 metal5 non-metallic6 metallic2 non-ferrous4 ferrous11.2true2 false - Alloys are mixtures, not compounds.3 true4 false- An alloying metal describes a metal added in a relatively small quantity.5 false - Steel is not a single element.
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