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Made in Space
This label "Made in Space" for industrial materials will probably surprise no one in the not so distant future. They may include superconductors, new kinds of alloys, substances with peculiar magnetic properties, supertransparent laser glass', polymers, plastics, and so on. Numerous experiments carried out at the Russian orbital space stations have paved the way2 to the development of methods and means of industrial production of new materials of better quality on board3 a spacecraft. Experts estimate that within a few coming years industrial production of various materials will be started in space.
Conditions on board a space vehicle drbiting the Earth greatly differ from those on its surface. However all of these conditions can be simulated4 on earth, except for one - - prolonged weightlessness. Weightlessness can be created on Earth, but only for a few seconds. A space flight is another matter: a satellite orbiting the Earth is in a dynamic zero-gravity state, i.e., when gravity is cancelled out5 by inertia.
What can weightlessness be used for? Many well-known processes go on differently due to the absence of weight. The Archimedes principle is no longer valid and, consequently, stable-state6 liquid mixtures can be obtained, the components of which would immediately separate on Earth because of different density. In case of melts' of metals, glasses or semiconductors, they can be cooled down to the solidification point even in space and then brought back to Earth. Such materials will possess quite unusual qualities.
In space there is no gravitational convection , i.e., movements of gases or liquids caused by difference of temperatures. It is well-known that various defects in semiconductors occur because of convection. Biochemists also have to deal with the worst aspects of convection, for example, in the production of superpure biologically active substances. Convection makes it very difficult on Earth.
Following the launch of the first orbital stations the specialists started experiments aimed at proving the advantages of the zero-gravity state for the production of certain materials. In this country all orbital stations from Salyut 5 onwards were used for that purpose, as well as rockets. Since 1976 over 600 technological experiments have been carried out on board manned and unmanned space vehicles.
The experiments proved that many of the properties of the materials obtained under the zero-gravity condition were much better than those produced on Earth. Besides, it has been established that it is necessary to develop a new science - physics of the weightless state - which forms the theoretical basis for space industry and space materials study. This science has basically been developed.The methods of mathematical modelling of the hydromechanical process under the zero-gravity condition have been created with the help of computers.
Special space vehicles will also be needed for industrial production of new-generation materials. Research has shown that the acceleration rate on board these vehicles must be reduced to the minimum. It was found that space platforms in independent flight carrying the equipment were most suitable for producing materials. These vehicles will have to use their own propulsion systems to approach their base orbital station after a certain period of time. The cosmonauts on board the station can replace the specimens. Many new and very interesting projects are planned for orbital stations. Here is one of them. Convection does not allow to grow large protein crystals on Earth. But it is possible to grow such crystals under the zero-gravity condition and to study their structure. The data obtained during the experiments can be useful for the work of laboratories on Earth in using the methods of gene engineering . Thus, it may be possible to make new materials in space and also to obtain valuable scientific data for new highly efficient technologies on Earth.
Preparatory work for industrial production in space at a larger scale is being carried out in Russia, the USA, Western Europe and Japan. It should be said that according to the estimates of American experts production of materials in space is to bring 60-billion dollars by the year 2000.
Прочитайте текст и расскажите о ноиом способе повышения пластичности и износостойкости режущего инструмента из композицио'"!'>й керамики.
Advanced ceramic materials have such interesting properties that mechanical engineers are becoming more and more interested in their use as structural parts (конструкционные детали).
Ceramic cutting tools have been in use for some lime. However, it is only during the last twenty years that there have been rapid development in this field because of the development of new composite ceramics.
Composite materials are materials in which two or more different; substances, such as metals, ceramics, glasses, or polymers are combined without chemical reaction. As a result one can produce a material with properties different from those of any of the individual constituents. The constituents of a composite would retain their individual characteristics.
Recently engineers have developed various kinds of composite ceramics which must combine an increased toughness (пластичность) with the same hardness and strength of usual ceramics. A promising recent development is the addition of a tiny quantity of metal to increase toughness and tool life. Thus, at room and high temperatures ( 100Q°C) the composite ceramics for cutting tools should possess the following properties: high strength, high toughness, high hardness, high thermal shock resistance and high chemical inertness.
Прочитайте текст, выделите интересные для вас факты и расскажите по-английски. Ancient Steel-Making Secret
When two metallurgists at Standford University were trying to produce a "superplastic" metal they became interested in the secret of Damascus steel, the legendary material used by numerous warriors (воины) of the past, including Crusaders (крестоносцы). Its formula had been lost for generations.
Analyses of a new steel revealed properties almost identical to those they found in Damascus steel, although their own plastic steel had been produced by present-day methods.
The remarkable characteristics of Damascus steel became known to Europe when the Crusaders reached the Middle East in the 11th century. They discovered that swords (меч) of the metal could split (рассечь) a feather( перо) in air and at the same time retain their edge sharp through many battles.
The secrets of Damascus steel were known in many parts of the ancient world, especially in Persia, where some of the finest specimens were produced. For eight centuries the Arab sword makers kept the secret about their techniques and methods. And with the invention of firearms (огнестрельное оружие), the secret was lost and it was never fully rediscovered.
The two metallurgists carried out a lot of researches. When they realized that they might be close to the discovery of a new material, a sword fancier (знаток) , at one of their demonstrations, pointed out that Damascus steel, like their own product, was very rich in carbon. This led them to conduct a comparative analysis of their steel and those of the ancient weapons. As a result, it was found that a basic requirement was a high carbon content. The two metallurgists believed it had to be from 1 per cent to 2 per cent, compared to only a part of 1 per cent in ordinary steel. Their research showed how to make steel of even greater hardness than Damascus steel.
Прочитайте текст. Расскажите по-английски, чем примечателен читальный зал Библиотеки Британского музея и какие отделы имеются в Британском музее.
The British Museum
The British Museum consisting of the National Museum of Archeology and Ethnography and the National Library is the largest and richest of its kind in the world. Built in the middle of the last century it is situated in central London which consists of quiet squares and streets.
The British Museum was founded by Act of Parliament in 1753 to bring together the collection of Sir Robert Cotton, some others and future addition to them.
Anthony Panizzi designed the famous circular Reading Room at the British Museum.The first thing that strikes a visitor on entering the Reading Room is its unusual shape. It is a perfect circle. The superintendent (управляющий) and his assistant sit in the centre of the room and they issue (выдавать) and collect books. Long rows of reading desks radiate to the outer walls, like the spokes (спицы) of the wheel.
Many famous people have used the Reading Room at the British Museum. Of the many distinguished people who have used the Reading Room no one was perhaps more regular and more intent (целеустремленный) than the German philosopher and socialist Karl Marx. Soon after he arrived in England in 1849, Marx became a daily visitor of the Reading Room, where he used to remain from nine in the morning till closing time.
The British Museum has a department of ethnography. Ethnograthy is concerned with primitive people and their cultures in various stages of development as revealed by their tools, ritual objects and various crafts (ремесло). This collection is so va^t that only a tiny percentage is on show to the general public. Then there is a department of prints and drawings. There are also departments devoted to maps, coins and medals. Visitors interested in chronology can see a large collection of clocks and watches. Those who are interested in philately can find a magnificent collection of postage stamps.