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 swimm
Creating artificial gills Background Taking in oxygen; mammals — lungs; fish — gills Long-held dreams — humans swimm
admin
2022-09-09
144
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
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 swiinming 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
beetles
解析
科学家观察那些没有腮的动物,它们能在水里利用气泡,特别是甲虫。录音原文中的notably“尤其.特别”是题目中especially的同义替换。
转载请注明原文地址:https://www.kaotiyun.com/show/mBnD777K
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
在考生文件夹下“student.mdb”数据库中有student、选课表和课程表。(1)以student、选课表和课程表为数据源,创建参数查询“按ID查询成绩”,实现输入学生的ID显示学生成绩,参数提示为“请输入学生ID’,结果显示学生姓名、课程名
考生文件夹下存在一个数据库文件“samp2.mdb”,里面已经设计好表对象“tStud”、“tScorc”和“tCourse”,试按以下要求完成设计:(1)创建一个查询,查找党员记录,并显示“姓名”、“性别”和“入校时间”。所建查询命名为“qT1
使用自动创建数据访问页功能创建数据访问页时,Access会在当前文件夹下,自动保存创建的数据访问页,其格式为()。
在考生文件夹中有“student.mdb”数据库。(1)将考生文件夹中的“成绩.xls”导入数据库,选课ID为主键,表的名字为“成绩”。(2)按照下表所示要求修改“成绩”表的设计,成绩字段的有效性规则是>=0And<=100。
PeopleallovertheworldknowWimbledonasthecentreoflawntennis.In1874itwasacountryvillage,butitwasthehome
Youmightbesurprisedtoknowthatbicycleshaveexistedforabouttwohundredyears,butnooneissurewhofirstmadethispo
AndylivedhighintheRockyMountains.Hehunted(打猎)wildanimalsthere.Healsotookothermenhunting.Thatwashiswork.
John:Mary,I’mlookingforsomething【K1】________(interest)toread.Anysuggestions?Mary:Icanrecommend(推荐)AllJoya
PacifictapaclothWhatdoesSandysayaboutthepapermulberrytree?
WhichTWOthingsmakethemuseumunusual?AtheguidesBtheeventsCtheanimalsDthebuildingsEthe
随机试题
给定程序MODI1.C中函数fun的功能是:从n(形参)个学生的成绩中统计出低于平均分的学生人数,此人数由函数值返回,平均分存放在形参aver所指的存储单元中。例如,若输入8名学生的成绩:80.5607290.59851.5
公司在有多余现金时,向股东回购自己的股票,以此来代替现金股利指的是()
下列有关缺铁性贫血治疗的叙述,错误的是
脊髓灰质炎病毒主要侵犯下列哪一个部位
甲型强心苷元的母核结构称为()
下列项目中,属于长期资产的有()。
企业战略是指企业为了适应未来环境的变化,寻求长期生存和稳定发展而制定的()的谋划与方略。
教师职业道德的调节功能仅仅作用于教师本身。()
对于向乡镇企业非法收费、摊派、罚款的,企业有权向什么单位控告、检举?()
直接调控方式是指国家主要运用经济手段,通过市场机制,影响和引导企业的经济行为,以达到宏观管经济调控的目标。()
最新回复
(
0
)