To be read after Lesson 4

To be read after Lesson 3

Nuclear Power? Well, Yes

Although nuclear reactors have generated electricity commer­cially for more than 40 years and nearly 400 now in operation, two major accidents — in the US in 1979 and Chernobyl in the USSR in 1986 — have put the industry under a radioactive cloud. In the popular imagination, reactors are nuclear bombs; even if they don't explode, they go on accumulating waste that will finally cause a global catastrophe.

As a result, an energy source once considered as the fuel of the future became questionable. But not everywhere. Nuclear power provides nearly a quarter of the electricity generated in the indus­trialized Western world by the 24-member countries of the Organi­zation for Economic Cooperation and Development. In France more than 76 % of electric power is nuclear-generated, in Belgium — 62 %, Sweden — 50 %, Germany, Switzerland, Spain and Fin­land come in at one third, Japan — a little less; Britain, the US and Canada — under 20 %. Some countries have no nuclear power plants at all and don't want any.

Not only the strong emotions of fear have worked against nu­clear power. Energy demand grew more slowly than expected in the past decade. Prices of oil and coal have reduced. However, energy prices can rise. Moreover, supplies of fossil fuel are limited, while

energy needs and tide (прилив) can't meet the increasing require­ments. Besides, nuclear power doesn't add to global warming.

All this causes the people to believe that the world can't live and work without nuclear power.

Telecommunication

A group of people enter a room, the lights go down, the screens come... the videoconference is under way.

Tomorrow's scientific fiction has become today's new technol­ogy -a daily reality for global companies who recognise the impor­tance of regular communication between groups of people in different locations around the world.

Essentially the videoconference room resembles a usual confer­ence room. Delegates sit along one side of a table facing their col­leagues on screen on the other side. They can see, hear and talk to each other simultaneously and can present slides of diagrams, even pieces of equipment. The technology is relatively simple. A device called videocodec takes the picture, digitalizes it for transmission over a special network and reforms the picture at the other end.

The problem today is to manufacture codec to the new interna­tional standard and to improve picture quality through faster trans­mission speeds. Research and development is also focusing on mobile videoconferencing with broadcast quality pictures which enable to have instant communication with colleagues around the world.

There is no doubt about the effectiveness of videoconferencing, as the videoconference eliminates the working time lost through travel.

The First Travelling Post Office

The first travelling post office in the United States was Abra­ham Lincoln's hat. That was a strange place, indeed, for mail; but that is where it was kept. Lincoln was appointed postmaster of New Salem, a small Western town, about the year 1833. The postman visited the place once a week and brought the mail — a dozen let­ters, perhaps, and two or three newspapers — in his saddle (седло) bags. He was always met by Postmaster Lincoln who put the letters into his hat for safekeeping. Lincoln was also the clerk in the coun­try store, so he had a good opportunity to distribute the mail. But if

people did not come for it, he put on his hat and delivered it. So New Salem was the first town in the US to have rural free delivery, even though the postmaster received very small pay for his work. At that time, stamps and envelopes were not used. When the sender of a letter paid the postal charges, the postmaster wrote PAID in the large letters on the face of the letter. But the postal rates were so high that the sender seldom paid them. Thus, the mailing charges were usually collected from the person who received the mail. The postmaster always held his postal receipts until a government rep­resentative came for them.

The Internet

The Internet is a magnificent global network with millions and millions of computers and people connected to one another where each day people worldwide exchange an immeasurable amount of information, electronic mail, news, resources and, more impor­tant, ideas.

It has grown at a surprising rate. Almost everyone has heard about it and an increasing number of people use it regularly. The current estimate is that over 70 million people are connected, in some way, to the Internet — whether they know it or not.

With a few touches at a keyboard a person can get access to ma­terials in almost everywhere. One can have access to full-text news­papers, magazines, journals, reference works, and even books. The Web is one of the best resources for up-to-date information. It is a hypertext-based system by which you can navigate through the Internet. Hypertext is the text that contains links to other docu­ments. A special program known as «browser» can help you find news, pictures, virtual museums, electronic magazines, etc. and print Web pages. You can also click on keywords or buttons that take you to other pages or other Web sites. This is possible because browsers understand hypertext markup language or code, a set of commands to indicate how a Web page is formatted and displayed.

Internet Video conferencing programs enable users to talk to and see each other, exchange textual and graphical information, and collaborate.

Internet TV sets allow you to surf the Web and have e-mail while you are watching TV, or vice versa. Imagine watching a film on TV and simultaneously accessing a Web site where you get in­formation on the actors of the film. The next generation of Internet-enabled televisions will incorporate a smart-card for

home shopping, banking and other interactive services. Internet-enabled TV means a TV set used as an Internet device.

The Internet is a good example of a wide area network (WAN). For long-distance or worldwide communications, computers are usually connected into a wide area network to form a single inte­grated network. Networks can be linked together by telephone lines or fibre-optic cables. Modern telecommunication systems use fi­bre-optic cables because they offer considerable advantages. The cables require little physical space, they are safe as they don't carry electricity, and they avoid electromagnetic interference.

Networks on different continents can also be connected via sat­ellites. Computers are connected by means of a modem to ordinary telephone lines or fibre-optic cables, which are linked to a dish ae­rial. Communication satellites receive and send signals on a trans­continental scale.

Дата добавления: 2014-12-17