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The concept is to develop vehicles that can run on a virtually limitless element hydrogen which when burned does not produce damaging fumes, but instead a bit of water vapour. The concept can solve two problems at once. First, it is a hedge for that day in the 21st century when hydrocarbon fuels run out, a prospect of no minor concern for the automotive industry.
Beyond that, the increasingly dire warnings by environmental scientists about the "greenhouse effect" in atomosphere caused by carbon dioxide exhausts adds urgency to the quest for a fuel that is less damaging to the environment.
Of course, there is a hitch to hydrogen, both carmakers admit :though the know -how to run vehicles on nature’ slightest element is already available, hydrogen is far from being cost competitive compared to hydrocarbon fuels, and further refinements hydrogen -propulsion technology will be required. But what we are discussing today is the technology of the year 2020.
But after several year's research Daimler and BMW engineers, in collaboration with other companies and research institutes in West Germany, independently have been tackling the technological and cost feasibility problems to be overcome in hydrogen fuel application.
In addition to the two concerns of technology and economic feasibility, the carmakers say, there is the issue of safety. The spectacular explosion of the dirigible. Hindenburg in 1937 immediately comes to mind, and skeptics wonder what the German autobahn would look like in one of the hundred - car pileups that routinely happen every winter if all the cars and tanks loaded with hydrogen.
A BMW engineer, Friedich Fickel, says that hydrogen is seen as less risky than gasoline. When leaked, hydrogen rises quickly up to the atmosphere, reducing the potential of explosion, whereas gasoline fumes linger close to the ground before dispersing. Still, both Daimler and BMW report that a considerable part of their development efforts are aimed at safe, lead - free storage of hydrogen fuel.
The related question is what is the best method of storage. By now ,the tests by both carmakers have all but eliminated using hydrogen in gas form. As a gas it takes up about 14 times the space of liquid hydrogen and as much as 30 percent can be lost by leakege unless the tanks are perfectly sealed.
Two other storage methods hold more promise. One is in liquid form, and the other in the form. of metal hydrides. In the latter, hydrogen if mixed with a metal alloy ,a process whereby the gas molecules are stored within the metal's molecular structure.
Which of the following is the characteristic of hydrogen？
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Tripod is ______.
American’s life has once again been greatly changed by the new age of science and technology since the Second World War. Everything has speeded up to a tremendous rate. Information is immediate, nobody has to wait to hear any news. There is a television set in every house. There is instant printing which has changed the way that offices and the universities run.
But perhaps the biggest change is the telephone. People no longer write letters to one another. They pick up the telephone. Every house has at least two, sometimes three, four and five telephones. Every office bas many telephones. It speeds things up. And its cost is not much.
Perhaps the biggest difference is in the growth of computers. Computers can think, can remember, can calculate faster than any human brain. A computer can hold more than a million facts in its memory. There are computers that are so big they would fill this entire auditorium with machinery. Businesses and banks are now managed by computers. Parts of the government are managed by computers. Students’ grades, their marks are all managed by computers.
However, if a computer makes a mistake about one of you, it is terribly difficult to correct that mistake. And sometimes a computer does make mistake, never learned by another computer and the same mistake will go into other computers. So in many ways people have become the servants of computers who are bigger and cleverer than they are. Of course, computers speed up every operation because computers can immediately record, remember facts and produce new information that it combines with these facts. It makes science possible. Modem science would not be possible without the computers to do the calculations:
Life is complicated. People need to know many technical skills to get money from a bank. You have to know how to work the automatic teller that will give you your money. You have to know how to use the new punch button telephones. Everything is very complicated. Many Americans find it so complicated, that they try to escape by drinking alcohol. Alcoholism is a major disease in America. Some people take drugs and some people belong to strange religion looking for some meaning in their life. I think perhaps you read about the terrible event in Guyana, when people who belong to a strange religion all committed suicide. This sort of thing would not have happened fifty years ago. It is a by-product of an age that has become too complicated for people to live in happily.
There are many contradictions in American society. Because of the complex way of life people are no longer the optimistic, self- reliant free people that they were when they were pioneers, when they were conquering the new land. Now people are becoming more pessimistic. Very often they are lonely. The doctors who have the most work are psychiatrists trying to help people find ways that they can again be happy. Often efficiency replaces good quality.
We still have two classes of people. Too much money is still in the hands of too few people. The rich capitalists no longer wear black hats and stripped trousers. They have faces that nobody knows because now they are called the "multi - national corporations. "They are the great faceless companies like General Motors, General Fords, United States Steel. There are no longer any faces like Mr. Rockefeller or Mr. Ford. They have become faceless forces, which control our government and control the money. The poorest class is still mostly made up of black people, minority people, Spanish speaking Americans. And the poorest people have not benefited from the new age of science and technology. So Americans are no longer the happy care-free people that they once were.
According to the passage, the characteristic of a highly technological society is ______.
In the late 1960s many people in North America turned their attention to environmental problems, and new steel-and-glass skyscrapers were widely criticized: Ecologists pointed out that a cluster of tall buildings in a city often overburdens public transportation and parking lot capacities.
Skyscrapers are also lavish comsumers, and wasters of electric power. In one recent year, the addition of 17 million square feet of skyscraper office space in New York City raised the peak daily demand for electricity by 120,000 kilowattsenough to supply the entire city of Albany, New York, for a day.
Glass-walled skyscraper's can be especially wasteful. The beat loss (or gain)through a wall of half-inch plate glass is more than ten times that through a typical masonry wall filled with insulation board. To lessen the strain on heating and air-conditioning equipment, builders of skyscrapers have begun to use double- glazed panels of glass, and reflective glasses coated with silver or gold mirror films that reduce glare as well as heat gain. However, mirror-walled skyscrapers raise the temperature of the surrounding air and affect neighboring buildings.
Skyscrapers put a severe strain on a city's sanitation facilities, too. (if fully occupied, the two World Trade Center towers in New York City would alone generate 2.25 million gallons of raw sewage each year-- as much as a city the size of Stanford, Connecticut, which has a population of more than 109,000. )
Skyscrapers also interfere with television reception, block bird flyways, and obstruct air traffic. In Boston in the late 1960s, some people even feared that shadows from skyscrapers would kill the grass on Boston Common.
Still, people continue to build skyscrapers for all the reasons that they have always built them--personal ambition, civic pride, and the desire of owners to have the largest possible amount of rentable space.
The main purpose of the passage is to ______.
The University of Washington
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