Half the commercial fishing grounds in the seas around Japan have been ruined by industrial waters. Tokyo police use an oxygen-inhaler after one hour of directing traffic.
The problem of filthy waters, dirty air and poisoned land is getting steadily worse.
Мапу vaguely worded antipollution bills passed by Parliament have had little effect.
Для специальности 270103 «Строительство и эксплуатация зданий и сооружений»
Young architects from the architectural department of the Rhode Island School of Design are dreaming up tomorrow's houses today.
One such house was designed with the help of research material by а graduate of this school. The system is based on cast plastic bubbles linked together, and it permits the creation of almost any size and shape of house. The walls will be giant curved sandwiches, with rigid plastic as outside surfaces and foamed plastic between to act as insulation.
This house will embody the features that are associating more and more with modern living; one-floor living, and а long, low line that makes it blend with its surroundings. The huge glass areas will admit lots of light, and will also tend to add outdoor space to the indoors and increase the feeling of speciousness.
Another house is а beautiful example of what engineers like to call "blue sky thinking". Its skeleton is а coil of magnesium alloy covered by а vapour barrier and а sprayed coat of concrete, and the floor is concrete. If glass were desired, it could be set between the coils of the frame. The entire structure would rest on pieces of curved precast masonry.
Wild thinking? On the contrary. According to its designer, the spiral framework would be compressed, just like а spring, for shipment to the site. Once there it is expanded, braced with welded pieces between coils, and the skin is applied. Thus would be solved the problem of manufacturing large pieces of house that are still transportable.
Other ideas come to mind. If а family has become larger and wishes to enlarge the house it might hire а pair of bulldozers and stretch their house out to more opulent dimensions.
Just at а time when the building of skyscrapers is moving ahead, attacks on these "megastructures" are spreading on а wide variety of fronts.
In San Francisco, officials set а 404-foot height limit on buildings in more than 95 per cent of residential areas in the city.
In Washington, efforts by builders to raise а height limit of 130 feet have been unsuccessful.
200 Storeys? Many builders are convinced that high-rise structures are an economic necessity in cities because of space shortage.
Engineers believe that tall buildings will rise to 200 storeys or more. In Chicago the Hancock Centre - or "Big John" as it’s known among architects - is а 95-million-dollar vertical city 1,127 feet high. Its 100 storeys contain department and grocery stores, 705 apartments, office space for 4,000 workers, restaurants, bank and recreational and parking facilities.
The management says its "megastructure" provides а complete living arrangement for more than 1,700 tenants - а place where people can live comfortably, without ever leaving the house. But some residents have complained of tedious elevator delays, "living above the weather", and "а sense of isolation from street life."
Experts in the field agree there are no structural limits to the potential height of buildings.
Effects on People. Some scientists think that the sway and vibrations caused in the upper storeys of tall buildings by high winds or minor earthquakes - cause discomfort and tension. Some tall building sway as much as 15 inches in strong winds.
Another structural problem has been to provide adequate foundation support for massive buildings.
What effect а tall building will have on the rest of а city is а question city planners should ask themselves before the building goes up. Architects and engineers should enter the political arena where questions about а building's effect on the ecology and the environment are asked. "Too often we get into the picture after it is too late", said one of the statesmen.
Now many people are beginning to feel that skyscrapers should not be considered the only option available in growing cities because skyscrapers have always been put up for reasons of advertisement and publicity.
Why does the Leaning Tower of Pisa lean? The answer is that its foundations were not soundly laid. From earliest times, architects and engineers have been aware of the problems involved in laying а building's foundations; but they have not always realized to what extent the earth can be pressed down by the; weight of а building. Too little allowance has sometimes been made for the possibility of а heavy structure's sinking unevenly.
If the earth is stable, laying the foundations of small buildings possess few problems. But in а tall modern structure the load may be very heavy indeed; and the foundation engineer has an extremely important job to do. To begin with, he must have а thorough understanding of soil mechanics, which entails а scientific study of the ground to see what load it can bear without dangerous movement.
Trial pits are dug, or holes are bored, in order to collect undisturbed samples of earth from various depths. By examining these, the engineer can forecast the probable shifts in the earth during and after building, according to the sort of foundation he designs. Thus he comes to the most important decision of all in the building's construction: He decides whether the earth is of the type that can best support each column on а separate solid block, or whether he must aim at lightness and, as it were, "float" the building on. hollow foundations.
If firm ground has been found only at great depth, the foundation engineer may use piles. These are solid shafts made either by driving reinforced, precast concrete deep into the ground, or by boring holes in the earth and pouring in the concrete. Each pile supports its load in one, or both, of two ways. It may serve as а column with its foot driven into solid earth or rock or it may stand firm because friction along its sides "grips" the column and prevents it from sinking.
But when it is а question of floating а building, the foundations take the form of а vast, hollow concrete box. This box is divided into chambers that will house heating and ventilating plants as well as provide garage and storage space for the building.
Luckiest of all are those foundation engineers whose buildings stand on hard rock like granite or ironstone. For them neither piles nor flotation need be used.
4,7 AT HOME IN BRITAIN
About 80 per cent of British people live in houses. Detached houses are usually in expensive suburbs, quite far from the town centre, near to the countryside. Semi-detached houses are often in suburbs which are nearer the town centre. Terraced houses and blocks of flats are mostly found in town centres. They can either be very small two-storey houses with one or two bedrooms or large houses with three to five floors and four or five bedrooms.
About 67 per cent of the people in Britain own their houses or flats. Most of the rest live in rented accommodation (2 per cent live in sheltered accommodation). People in Britain buy houses or flats because there is not enough rented accommodation and what there is can be expensive.
One of the most important materials produced by the silicate industry is cement. It is employed in enormous quantities in all kinds of construction work.
Cement is prepared by roasting clay together with limestone until they cake. For this purpose the clay and limestone are first thoroughly mixed and then strongly heated. When the cement mixture is roasted, the calcium carbonate decomposes into carbon dioxide and calcium oxide, which reacts with clay, forming calcium silicates and aluminates. The cement mixture is roasted in special cylindrical rotary kilns.
A kiln of this kind is a large tube made of thick sheet steel, slightly inclined and lined on the inside with refractory materials.
The cement mixture is usually prepared artificially from limestone and clay. But there are in nature lime-clay rocks called marls, which correspond exactly in composition to the cement mixture. Large deposits of marls, used for the production of cement, are found in the USSR.
Для специальностей 140613 «Техническая эксплуатация и обслуживание электрического и электромеханического оборудования»
0,1 ELECTRONICS AND ТНЕ CITY
Many different kinds of urban difficulties could be lessened bу transporting men in new ways.
An explorer of our society from another planet may well wonder at our inability to use city streets in view of our ability to use strands of wire.
Morse could only send one message at а time through а wire in 1845, we now send dozens simultaneously. The wire is по larger, but we use it better. Mathematical resolution of communication phenomena has enabled us to do this. Similar analysis of transportation systems have shown that our use of city streets as about as primitive as Mr. Morse's use of wire. Their carrying capacities, too, could be increased.
The electronic engineers have numerous technique for increasing channel’s capacity. One is to digitalize information by counting bits of it.
Although it is not feasible to transport man from one place to another the way we transmit his voice, it is quite easy to count the human heads rather than vehicles flowing through city streets. This suggests several different ways of getting waves of people through streets faster.
In cities, of course, streets intersections are numerous and troublesome. We control the traffic flow through many busy intersections with crude signal lights. They cannot distinguish between а bus, carrying 50 persons and а lone bоy on the motorcycle. It would be quite easy to enable them to do this — by putting special signals in the buses (that wouldn't disturb even а dog' s sleep) and receivers in the signal light boxes. The control mechanism then could delay one person а few seconds to give 50 people that many seconds. Such electronic devices are becoming cheaper and would soon be tried if we seriously set out to maximize the flow of people rather than the flow of vehicles.
Circuits can be divided into four classes: series, parallel, combination of series-parallel, and network.
Series circuits are those having only one closed path for the flow of electricity. All the elements, or devices which make up the circuit are connected in tandem, one after the other, so that the end of one is connected to the beginning of the other; or, in other words, the positive terminal of one is connected to the negative terminal of another. If the series circuit is opened anywhere, the current will not flow through the circuit.
A parallel circuit is one divided into two or more branches, each branch carrying part of the current. Another way of saying the same thing is that all the elements or devices are connected so that one half of the terminals are fastened to a common point or a common conductor, and the other half are fastened to another common point, or another conductor.
3,6 MEASURING DEVICES
A voltmeter is connected in parallel across the points of a circuit where the difference of potential is to be measured. The resistance of the operating coil must, in this instance, be as high as possible, to limit the amount of current consumed by it, or else a drop in potential due to the meter would occur and the pointer indication would not represent the true potential difference across the circuit.
In the modern conception of the constitution of matter it is composed of atoms. The atom is made up of positive nucleus surrounded by negative charges of electricity, called electrons, which revolve about the nucleus at tremendous speeds. The nucleus consists of a number of protons, each with a single positive charge, and, except for hydrogen, one or more neutrons, which have no charge. The atom is neutral when it contains equal numbers of electrons than protons. A positively charged body is one which contains fewer electrons than its normal number.
When the two ends of a conductor are connected to two points at different potentials, such as the terminals of a battery, we say that there is an electric current in the conductor.
The conductor has equal numbers of positive and negative charges in its atoms. The atoms in metals are packed so closely that they overlap to some extent, so that it is comparatively easy for the outer electrons to pass from one atom to another if a small force is applied to them. The battery causes a potential difference between the ends of the wire, and thus provides forces that make the negative electrons in the wire move toward the point of higher potential. This electron flow toward the positive electrode is the electric current.
The current will not flow unless there is an electric circuit. The magnitude of the current depends simply on the rate of flow of electrons along the conductor.
9,8 SUNLIGHT INTO ELECTRICITY
Solar thermal electric generators have already been made. This is a semi-conductor thermal electric battery placed at the focal point of a mirror. The surface of the battery absorbs the reflected sunlight focused on it and warms up. Meanwhile the-other side of the battery is kept cool, for instance, by a stream of cold water. Owing to the difference in temperatures, electricity is generated. The capacity is equal to ten watts; although not very much, it is quite enough to work a desk fan or feed a radio set.
Construction has now begun on a one-kilowatt solar thermal generator. This sort of thing may be employed not only to supply electricity to radio sets, telephone lines, radio stations and like, but also to obtain mechanical energy in order to operate small water-pumping machines, and to provide lighting for buildings as well.
Another way of tackling the problem of the direct transformation of radiant, energy into electricity is to ; use a silicon photo - electric cell based on the principle of the so-called photo-effect. On impinging upon a silicon plate, light induces an electric current. Batteries of this king were installed in the Soviet sputniks and other space craft.
The cost of electricity generated by solar batteries is still comparatively high. One way of cutting down costs is to make the batteries more efficient, and in this respect, our scientists have made the noteworthy progress.
Для специальности 150411 «Монтаж и техническая эксплуатация промышленного оборудования»
0,1 METALS
Metals are materials most widely used in industry because of their properties. The study of the production and properties of metals is known as metallurgy.
The separation between the atoms in metals is small, so most metals are dense. The atoms are arranged regularly and can slide over each other. That is why metals are malleable (can be deformed and bent without fracture) and ductile (can be drawn into wire). Metals vary greatly in their properties. For example, lead is soft and can be bent by hand, while iron can only be worked by hammering at red heat.
The regular arrangement of atoms in metals gives them a crystalline structure. Irregular crystals are called grains. The properties of the metals depend on the size, shape, orientation, and composition of these grains. In general, a metal with small grains will be harder and stronger than one with coarse grains.
Heat treatment such as quenching, tempering, or annealing controls the nature of the grains and their size in the metal. Small amounts of other metals (less than 1 per cent) are often added to a pure metal. This is called alloying (легирование) and it changes the grain structure and properties of metals.
The ways of working a metal depend on its properties. Many metals can be melted and cast in moulds, but special conditions are required for metals that react with air.