M. Ibbotson - Professional english in use engineering (794233), страница 7
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The first one has been done for you.1 m2 mm4 m25m3metres3m~9.37 kglm 36~Complete the extract from an article about satellite design using the words in the box. Lookat A and B opposite to help you.cubicgravitylightweightmasssquareweighweightlessSatellites need to be designed to cope with two very differentphases: deployment (the journey into space by rocket) and operation(working in space).For the first phase, engineers are faced with the problem that every(1) ................................ metre of volume taken up within the rocket will addmillions of dollars to its ticket into space.
And each extra gram of(2) ................................ added to the craft will increase the fuel needed topropel it upwards against the pull of (3) ................................. That extra fuel,in turn, will (4) ................................ a little more, further adding to the totalweight of the craft.
With the cost of kilograms so high, the satellite musttherefore be as (5) ................................ as possible.In the second phase, with the orbiting satellite now (6) ................................ ,its mass is practically irrelevant. As for the amount of space occupied,the situation is completely reversed. The satellite's solar panels, whichtransform sunlight into battery power, must unfold to cover as wide anarea as possible- opening out to cover an area of several(7) ................................ metres- in order to maximize their exposure to the sun.ov~r .f-o tjotc ~Talk about different materials that are suitable for specific engineering uses due to theirdensity - because they are either very dense, or very lightweight.Professional English in Use Engineering25Measurable parametersSupply, demand and capacityThe article below is fro m the technology section of a business magazine.Calculating the capacity of an electricity grid -the amount of energy it needs to supply to users-might seem simple.
Just add up the power supplied over a given period of t ime to give the totalamount consumed by users. Then, divide the cumulative amount of power used during the wholeperiod by the number of hours in the period.The result is an average level of consumption per hour.But there's one problem w it h this method -and it's a major one.The rate of power consumpt ion -the amount that's being consumed at a particular moment- isnot constant. In other words, consumption does not stay at the same level all the t ime. So electricitysupply requireme nts ca nnot simply be averaged out over t ime. People use more power at certaintimes of day, and less at other times, which means that demand for power fluctuates sign ificant ly.Generally, it rises to a maximum in the evening (peak demand is at evening mea ltimes), and fa lls toits lowest levels during the night.
These fluctuations are so big that at peak times consumptioncan be twice as high as it is during off-peak times. Clearly, the grid needs to have sufficient capacityto meet demand when consumption peaks. But since each peak is brief, the grid w ill only run tocapacity - at or close to its maximum capability- for a few moments each day. This means, most ofthe time, it has sign ificant spare capacity.-Input, output and efficiencyPower lines and transformers are relatively inefficient, wasting energy - ma inly by giving off heat.As a res ult, there is a difference between input - the amount of energy put into the grid by powerstations, and output - the amount used by consumers.
On a typical grid, the difference betweeninput and output is about 7%- th ere is a 7% energy loss. Bu t if electricity is generated at the placewhere it's consumed, and not transmitted through long-distance power lines, this loss can beavoided. Consequently, locally produced electricity is more efficient than grid-supplied power, asthere is a gain in efficiency of around 7%.One way to produce power loca lly is with photovoltaics(PVs) - often called solar panels. However, many PVinstallations are stil l con nected to the electricity grid.This means that when there is surplus power - whenelectricity is being produced by t he solar panels fasterthan it is needed in the home - it is fed into the grid.If consumption exceeds production - if electricity isbeing used in the home faster than the solar panels canproduce it - then power is taken from t he grid.
Homeswith low consumption may therefore become netprod ucers of power, producing more electricity t hanthey consume.26Professional English in Use Engineering10.1An engineer is talking to a colleague about the design of a fuel tank for a water pump.Complete the explanation using the words in the box. Look at A opposite to help you.averagecapacityconstantconsumeconsumptioncumulativedurationratef-uel (I) ................................
fo( -this e.ngine. is abou-t \.? \i-t(e.s pe( hou(. OfCCXJ(.5e.,some.-time.st-t'\1 (2) ................................ a bi-t mQ(e., some.-time.s a bi-t le.ss, de.pendlng on -the. wo(\:.load . !J<.tt\.? is an ('~) ................................ figu(e.
. And le.-t 's sa'j -the. (4) ................................ of a WO(\:. shifTIs 5 hou(s. lhe. pump Will have. -to be.. s-topped oc.c.asionall'j, -to cle.an -the. in-tak.e. fil-te.(,so i-t won '-t be.. 5 hou(s of (')) ................................ (<Jnning. !J<.ttwe. '11sa'j 5 hours, -to be.. on-the. safe. side.. So 5 hours of (Unning a-t a (lo) ................................ of \.? li-t(e.s pe( hou( give.s12 lrt(e.s of (7) ................................
consump-tion over a shifT.So if we. wan-t -the. pump -to have.sufficie.n-t fuel a<.ttonom'j fO( an 5-hou( shifT, -the. (e) ................................ of -the. fuel -tank.ne.e.ds -to be.. 12 1!-t(e.s, minimum.10.2The graph below shows water consumption in a washing process at a manufacturing plant.Write figures to complete the comments. Look at A opposite to help you.Water consumption fluctuated between ................ and ................
litres per second.2 Averaged out over the period shown, consumption was roughly ................ litres per second.3 Consumption peaked at a rate of ................ litres per second.4 If the process ran to capacity, it could use water at a rate of ................ litres per second.5 When consumption peaked, the process had spare capacity of ................
litres per second.1098.................................. Maximum supply capabi lity7 -------- --------654-321o +-----.-----.------.-----.-------r------, Cumulative time - seconds010.3102030405060Choose the correct words from the brackets to complete the explanations from a guided tourof a manufacturing plant.
Look at A and B opposite to help you.A lot of heat is generated in this part of the process. And all of that (input I output) isrecycled- it provides a (demand I supply) of heat for the next stage of the process. So it'squite an (efficient I inefficient) system.2 Sometimes, there's (insufficient I surplus) heat, and it can't all be recycled. At other timesthere isn't quite enough recycled heat to keep up with (peak I off-peak) demand for heatenergy further along the process.3 Some material is lost in the washing process, but the mass of water absorbed is greaterthan the mass of material lost. So there's a net (loss I gain) in total mass.ov~r .f-o t:fotc ~Think of an energy-consuming appliance you're familiar with.
Imagine you are starting aproject to redesign it, in order to improve its efficiency. Answer the following questions:•How much energy does the appliance consume? Is consumption constant or fluctuating?Describe any fluctuations, in terms of average and peak consumption.•How efficient is the appliance? What are the main reasons for inefficiencies? What areyour first thoughts on how efficiency could be improved?Professional English in Use Engineering27Material types-Metals and non-metalsEngineering materials can be divided into:•metals- examples of metallic materials are iron (Fe) and copper (Cu)•non-metals- examples of non-metallic materials are carbon (C) and silicon (Si).As iron is such a widely used material, metals can be divided into:-•ferrous metals- those that contain iron•non-ferrous metals- those that do not contain iron.Elements, compounds and mixturesWith regard to the chemical composition of materials -the chemicals they contain, and howthose chemicals are combined- three main categories can be used:•Elements are pure materials in their most basic form.
They cannot be broken down intodifferent constituents ('ingredients'). Examples of elements widely used in engineeringmaterials are iron, carbon and aluminium (AI) .•Compounds consist of two or more elements that are chemically bound - that is,combined by a chemical reaction. An everyday example is water, which is a compound ofhydrogen (H) and oxygen (0).•Mixtures consist of two or more elements or compounds which are mixed together, butwhich are not chemically bound. In engineering, common examples are alloys -that is,metals which have other metals and/or non-metals mixed with them.
A common exampleis steel, which is an iron-carbon alloy, and can include other alloying metals- metalswhich are added to alloys, in small quantities relative to the main metal. Examples ofwidely used alloying metals are chromium (Cr), manganese (Mn) and tungsten (W).IBrE: aluminium /,rel.jo'mm.i.~m/; ArnE: aluminum /~'lu: . mr.n~m/1Note: For a list of chemical elements and their symbols, see Appendix IV on page 104.-Composite materialsThe article below is from an engineering journal.Materials under the microscope: compositeshen you think of examples of hi-tech materials,composite materials come to mind- such ascarbon-fibre, used in aerospace and Formula 1 cars.But although we think of composites as hi-tech andhighly expensive, that's not always true.
The earliestexamples of composite materials were bricks madefrom mud and straw. Or, to use the correct compositeterms, from straw reinforcement- the structuralnetwork that reinforces the material inside, and a mudmatrix- the material surrounding the reinforcement.These terms explain what a composite material is: amatrix with a reinforcing material inside it. A modern,everyday example is fibreglass- correctly called glassreinforced plastic (GRP) -which has a plastic matrixreinforced with glass fibres.W28Professional English in Use Engineering11.1Complete the sentences using the words in the box. Look at A opposite and Appendix IV onpage 104 to help you.metalnon-metalmetallicnon-metallicferrousnon-ferrous1 Carbon (C) is a ................................ .2 Copper (Cu) is a ................................
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