首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Creating artificial gills Background Taking in oxygen; mammals — lungs; fish — gills Long-held dreams — humans swimming
Creating artificial gills Background Taking in oxygen; mammals — lungs; fish — gills Long-held dreams — humans swimming
admin
2022-03-30
102
问题
Creating artificial gills
Background
Taking in oxygen; mammals — lungs; fish — gills
Long-held dreams — humans swimming underwater without oxygen tanks
Oxygen tanks considered too【L31】________and large
Attempts to extract oxygen directly from water
1960s — prediction that humans would have gills added by【L32】________
Ideas for artificial gills were inspired by research on
fish gills
fish swim bladders
animals without gills — especially bubbles used by【L33】________
Building a simple artificial gill
Make a watertight box of a material which lets【L34】________pass through
Fill with air and submerge in water
Important that the diver and the water keep【L35】________
The gill has to have a large【L36】________
Designers often use a network of small【L37】________on their gill
Main limitation — problems caused by increased【L38】________ in deeper water
Other applications
Supplying oxygen for use on【L39】________
Powering【L40】________cells for driving machinery underwater
【L34】
In my talk today I’ll be exploring the idea of artificial gills. I’ll start by introducing the concept, giving some background and so forth and then I’ll go on to explain the technological applications, including a short, very simple, experiment I conducted.
Starting with the background... As everyone knows, all living creatures need oxygen to live. Mammals take in oxygen from the atmosphere by using their lungs, and fishes take oxygen from water by means of their gills, which of course in most fishes are located either side of their head.
But human beings have always dreamt of being able to swim underwater like the fishes, breathing without the help of oxygen tanks. I don’t know whether any of you have done any scuba diving but it’s a real pain having to use all that equipment. You need special training,
and it’s generally agreed that tanks are too heavy and big
to enable most people to move and work comfortably underwater. So scientists are trying a different tack: rather than humans carrying an oxygen supply as they go underwater, wouldn’t it possible to extract oxygen in situ, that is, directly from the water, whilst swimming?
In the nineteen sixties the famous underwater explorer Jacques Cousteau, for example,
predicted that one day surgery could be used to equip humans with gills.
He believed our lungs could be bypassed and we would learn to live underwater just as naturally as we live on land. But of course, most of us would prefer not to go to such extremes.
I’ve been looking at some fairly simple technologies developed to extract oxygen from water — ways to produce a simple, practical artificial gill enabling humans to live and breathe in water without harm. Now, how scientists and inventors went about this was to look at the way different animals handled this — fairly obviously they looked at the way fishes breathe but also how they move down and float up to the surface using inflatable sacs, called swim bladders.
Scientists also looked at animals without gills, which use bubbles of air underwater, notably beetles.
These insects contrive to stay underwater for long periods by breathing from this bubble which they hold under their wing cases.
By looking at these animal adaptations, inventors began to come up with their own ’artificial gills’. Now making a crude gill is actually rather easy — more straightforward than you would think. You take a watertight box,
which is made of a material which is permeable to gas, that is, it allows it to pass through,
inwards and outwards. You then fill this with air, fix it to the diver’s face and go down underwater.
But a crucial factor is that the diver has to keep the water moving,
so that water high in oxygen is always in contact with the gill, so he can’t really stay still.
And to maximise this contact it’s necessary for your gill to have a big surface area.
Different gill designers have addressed this problem in different ways,
but many choose to use a network or lattice-arrangement of tiny tubes as part of their artificial gills.
Then the diver is able to breathe in and out — oxygen from the water passes through the outer walls of the gill and carbon-dioxide is expelled. In a nut-shell, that’s how the artificial gill works.
So, having read about these simple gill mechanisms, I decided to create my own. I followed the procedure I’ve just described and it worked pretty well when I tried it out in the swimming pool... I lasted underwater for nearly forty minutes! However, I’ve read about other people breathing through their gill for several hours.
So the basic idea works well,
but the real limitation is that these simple gills don’t work as the diver descends to any great depth because the pressure builds
and a whole different set of problems are caused by that. Research is being done into how these problems might be overcome, but that’s another story which has to be the subject of another talk!
Despite this serious limitation, many people have high hopes for the artificial gill and they think it might have applications beyond simply enabling an individual to stay underwater for a length of time. For example,
the same technology might be used to provide oxygen for submarines,
enabling them to stay submerged for months on end without resorting to potentially dangerous technologies such as nuclear power.
Another idea is to use oxygen derived from the water as energy for fuel cells.
These could power machinery underwater, such as robotic devices...
So, in my view, this is an area of technology with great potential. Now, if anyone has any questions, I’d be happy to answer...
选项
答案
gas
解析
你带上防水的箱子,它是用气体能渗透的材质做成的。录音原文中的be permeable to sth.“可渗入某物的”对应题目中的lets sth.passthrough,即是气体能穿过的,故应填入gas。
转载请注明原文地址:https://kaotiyun.com/show/tq8O777K
本试题收录于:
雅思听力题库雅思(IELTS)分类
0
雅思听力
雅思(IELTS)
相关试题推荐
LookattheintroductiontoWestThamesCollegeonthefollowingpageandatthestatements(Questions14~20)below.Inboxes14-
ChoosethemostsuitableheadingsforparagraphsB-Efromthelistofheadingsbelow.Writetheappropriatenumbersi-ixinboxes
Completethetablebelow.ChooseNOMORETHANTHREEWORDSORANUMBERfromReadingPassage1foreachanswer.Writeyouranswers
NewZealandSeaweedCallusnotweeds;weareflowersofthesea.SectionASeaweedisaparticularlynutritiousfood,whichabs
TheStudyofChimpanzeeCultureA.Afterstudyingthesimilaritiesbetweenchimpanzeesandhumansforyears,researchershav
CompletethenotesbelowbywritingNOMORETHANTHREEWORDSinthespacesprovided.TheGovernmentplanstogive【T14】$______to
1.8定位句为“Well,thebusis$1.8incashandthetrainis$10eachway.”。本题中的定位词在听力中原词出现,但注意排除与train相关的干扰信息;另外,需要注意的是在听力前预测答案时,应该观察表格
conversation/tocommunicate本题有关这位男士学日语的特定需求。录音原文中Iwillneedtobeableto…和I’llputdown提示其后为答案。由于题目要求不超过三个词,因此该空填写名词或者动词短语均可。
CDs本题有关这款DVD的产品特征。录音原文中的aswellas是题目中also的同义替换。
Carsblockingpathscouldpreventaccessby__________inanemergency.
随机试题
红细胞大量破坏时主要通过释放下列哪项物质引起DIC
5岁患儿突发寒战、高热,左大腿下端深压痛,患肢不敢动,白细胞总数升高。最有意义的诊断方法是
伤暑,发热头痛,恶寒无汗,口渴面赤,胸闷不舒,舌苔白腻,脉浮数者,治宜选用
手阳明大肠经的原穴是
A、维生素K3B、维生素CC、维生素D2D、维生素B6E、维生素E分子结构为甲萘醌磺酸钠的是()
西方戏剧求逼真,说白动作,完全要逼近真实;而中国戏剧却求与真实隔开一层,达到教人放松、教人解脱的效果。中西方戏剧在世界整个文化体系中,各有各的特点与意义。在五四运动时。一般人提倡西方剧,尤其如易卜生,说他能在每一本戏剧中提出一人生问题来。其实中国
监理大纲评审时应重点评审监理大纲的()。
使用铁路长大货物车(D型)装运货物时,应核收()。
A公司为增值税一般纳税人,不动产、动产适用的增值税税率分别为11%、17%。2017年A公司建造一个生产车间,包括厂房和一条生产线两个单项工程。厂房造价为130万元,生产线安装费用为50万元。A公司采用出包方式出包给甲公司。2017年有关资料如下:资料一
为了鼓励市民积极参与志愿者活动,某市出台一项政策,为优秀志愿者提供报酬和慰问品,有人认为这有违志愿者服务的理念。你怎么看?
最新回复
(
0
)