給排水專業(yè)外語(yǔ)PPT

1、Environmental English Noise Control1 The control of noise is possible at three levels:reducing the sound produced;interrupting the path of the sound;protecting the recipient; When we consider noise control in industry,in the community,or in our home,we should keep in mind that all problems have thes

2、e three possible solutions.2 Industrial Noise Control Industrial noise control generally involves the replacement of noise-producing machinery or equipment with quiet alternatives.For example,the noise from an air fan may be reduced by increasing the number of blades and decreasing the rotational sp

3、eed.工業(yè)噪聲控制工業(yè)噪聲控制通常包括用安靜的設(shè)備替換產(chǎn)生噪聲的機(jī)器和設(shè)備。例如，由風(fēng)扇產(chǎn)生的噪音可以通過(guò)增加葉片的數(shù)量和降低轉(zhuǎn)速的方法來(lái)減小。3 The second method of decreasing industrial noise is to interrupt the path,for example,by covering a noisy motor with insulating material. The third method of noise control,often used in industry,is to protect the recipient by

4、 distributing earmuffs to the employees.But the problem is thus not really solved,and often the workers refuse to wear earmuffs,considering them sissy.Such wrong concept will only end in deafness.第二個(gè)減小工業(yè)噪聲的方法是中斷噪聲傳播路線，例如，通過(guò)用絕緣材料覆蓋產(chǎn)生噪聲的發(fā)動(dòng)機(jī)。第三個(gè)通常被用于減小工業(yè)噪聲的方法是通過(guò)給雇傭者發(fā)放耳套來(lái)保護(hù)噪聲接受者。但是噪聲問(wèn)題沒(méi)有被真正解決，工人認(rèn)為耳套女子氣而

5、拒絕帶它們。這個(gè)錯(cuò)誤的觀念將最終導(dǎo)致耳聾。4Community Noise Control The three major sources of community noise are aircraft, highway traffic and construction. Construction noise must be controlled by local ordinance.Control usually involves the muffling of air compressors,jack hammers, hand compactors,etc.Since mufflers

6、cost money,contractors will not take it upon themselves to control noise,and outside pressures must be exerted.社區(qū)噪聲控制社區(qū)噪聲的三個(gè)主要來(lái)源是航空，高速公路和建筑噪聲。建筑噪聲必須通過(guò)當(dāng)?shù)胤蓷l例來(lái)控制。控制通常包括空氣壓縮機(jī)、氣錘和手動(dòng)壓實(shí)器等的消聲。由于消聲器成本高，承建者不會(huì)運(yùn)用它去控制噪聲，必須通過(guò)外界的壓力來(lái)實(shí)現(xiàn)。5 Aircraft noise in the United States is the province of the Federal Aviation A

7、dministration,which has instituted a two-pronged attack on this problem.First,it has set limits on aircraft engine noise and will not allow aircraft exceeding these limits to use the airports.This has forced manufacturers to design for quiet as well as for thrust. The second efforts has been to dive

8、rt flight paths away from populated areas and whenever necessary to have pilots use less than maximum power when the takeoff carries them over a noise-sensitive area. 在美國(guó)，航空噪聲是聯(lián)邦航空管理局的管轄范圍，聯(lián)邦航空管理局已經(jīng)就這一問(wèn)題制定了兩個(gè)嚴(yán)格的措施。首先，它對(duì)飛機(jī)發(fā)動(dòng)機(jī)噪聲設(shè)定限度并且不允許超過(guò)限度的飛機(jī)使用飛機(jī)場(chǎng)，這一點(diǎn)要求制造商設(shè)計(jì)出安靜且推動(dòng)力大的飛機(jī)。第二個(gè)措施是轉(zhuǎn)移航線使其遠(yuǎn)離人口密集區(qū)并且無(wú)論何時(shí)只要需要就

9、讓飛行員通過(guò)噪聲敏感地區(qū)時(shí)使用少于最大量燃料。6Noise in the Home Private dwellings are getting noisier because of internally produced noise as well as external community noise.Conclusion As long as noise was considered just another annoyance in a polluted world,not much attention was given to it. We now have enough data to show that noise is a definite health hazard and should be n