1. To make a contribution — внести вклад

2. To win recognition — получить призвание

3. To put into practice — осуществлять

TELECOMMUNICATIONS AND TV CENTRE

Different ways of sending messages over long distances have been known and employed for thousands of years. But most important developments in the field of telecom­munications have been made over the last hundred years.

Most modern methods of telecommunication employ electricity. In 1820 it was discovered that an electric current could deflect a magnetic needle to the left or to the right, according to the direction in which the current was flowing. This discovery made possible the invention of the telegraph.

The telephone, which transmits speech, was a later invention. All sources of sound vibrate the air in differ­ent ways. The vibrations of a voice speaking into the mi­crophone of a telephone cause vibrations in an electric current. This varying current is carried along a wire to a receiver, in which a thin metal plate vibrates in the same way ¹ as the original voice.

Moving pictures ² can be sent by television. Originally only black-and-white pictures could be transmitted, and the distances over which they could be sent were rela­tively short. But colour television has now been developed, and telecommunication satellites have made inter-con­tinental television transmission possible.

In order to coordinate all the TV centres in our country a new USSR TV Centre has been built. It also en­sures contaet with other countries through Intervision and Eurovision.

The 533-metre ferroconcrete TV tower at Ostanklno, in the northern section of Moscow, is one of the world's tallest free-standing structures. It houses the broadcast­ing and TV stations, the apparatus and communication systems, the equipment and instruments of the Central High-Altitude Hydro-meteorological Observatory, as well as a restaurant, observation platforms and a conference hail.

Television now plays an important part in many peo­ple's lives. Television informs people about current events, the latest developments in science and politics, and offers different programmes which are both interesting and in­structive.

Notes

1. In the same way — таким же образом

2. Moving pictures — (движущиеся) изображения

SILENT METALS

(to be read after Lesson 9)

A hundred years ago noise on the main streets of the world's biggest cities did not exceed 61 .decibels.¹ Today it is 100 and more. Industrial noise is at very high level at many factories, and in some it reaches 90 to 110 deci­bels.

Noise is an ever growing inconvenience of modern life, and much of it is generated by vibrations of metals. These vibrations not only cause noise but can also lead to "fatigue" and consequent failure of a structure.

Research into methods which can minimize vibrations in structures is therefore of considerable importance. There are two methods to reduce vibration in an engi­neering design; either we make the structure so stiff and heavy that it cannot vibrate significantly, or we intro­duce "damping" ² into the structure, that is, we have .to introduce some mechanism for the absorption of energy within the system.

To apply damping coating is standard practice today. The damping coatings are usually made of plastics and are applied to sheet-metal shells ³ such as car bodies. This method is often cheap and has the advantage that the coating can be applied precisely where damping is required. But these damping coatings may be efficient for certain sound frequencies and temperatures.

So metallurgists were interested in the possibility of metals that are strong and tough enough to be used in structures. But they must also possess a high inherent damping capacity ⁴ that is independent of frequency and less temperature-dependent than that of plastics.

Scientists want to combine some of the properties, which characterize steel, with high damping capacity of lead and to produce a material that could be used to minimize noise and vibration. This can, in fact, be done with sev­eral materials, the most outstanding of which are alloys of manganese and copper. These alloys can be .stronger than ordinary steel, with similar toughness and hardness, yet S they have a damping capacity nearly 50 times great­er than that of steel.

However, noise and vibration are problems to be faced by engineers. It is seldom sufficient merely to replace * a troublesome component with one of a high-damping alloy. The particular characteristics of these "high-damp­ing" structural alloys should be properly employed. As a result, perhaps, the future will be a little quieter—In some respects at least! ^г

Notes

1. decibel — децибел (db) = 0,1 b; b (бел) >— акустическая еди­ница измерения

2. damping — демпфирование

3. to sheet-metal shells — к наружным частям, сделанным из листового железа

4. a high Inherent damping capacity — способность сильного внутреннего демпфирования

5. yet — sd. но

6. it Is seldom sufficient merely to replace — редко бывает доста­точно лишь заменить

7. at least — по крайней мере

FLAMELESS FIRE

For centuries it was a common practice that in order to get an alloy of two hard substances they must be first melted down. But Soviet scientists replaced high-temper­ature furnaces by a reactor, in which fire has no flame. It is called flameless fire. Substances were found that don't give off gases when they are burning. A mixture of titanium and boron was pressed into a very large tablet and was ignited by a wire spiral which was heated by elec­tric current. A bright wave of light rapidly spread along the tablet from the point of its contact with the spiral. The experimenters paid attention to the fact that the tab­let had neither smelted nor lost its initial form, but had become dense and hard. They got a titanium-boron com­pound—a substance with excellent abrasive properties. Normally to obtain this alloy the process lasted several hours in a special kind of furnace. In the new method it took them only a few seconds to produce the alloy. The scientists had to make lots of experiments and thermody­namic calculations to find out what actually goes on ¹ inside the tablet at the moment when it receives the ther­mal pulse. A vast new section appeared in chemistry— the gasless combustion theory.

The process of getting alloys has become much quicker and much cheaper, energy is saved which was used to keep up high temperature in furnace. The quality of the product has improved, and all the undesirable substances are burnt out. In" other words, self-purification of the alloy takes place.

As we see fire has appeared in a new role: instead of destructive element it has become a fine chemist synthe­sizer, a creator of alloys.

Note