Английский / Английский язык.2 курс

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used in maintenance and repair work. The welding unit can be moved on a two wheel cart or transported by truck to any field job where breakdowns occur. Its adaptability makes the oxyacetylene process usually suitable for welding, brazing, cutting and heat treating.

The chief advantage of are welding is the rapidity with which a high quality weld can be made at a relatively low cost. Specific applications of this process are found in the manufacture of structural steel for buildings, bridges, and machinery. Arc welding is considered ideal for making storage and pressure tanks as well as for production line products using standard commercial metals.

Since the development of gas – shielded arc processes, there are indications that they will be used extensively in the future in welding all types of ferrous and nonferrous metals in both gage or plate thickness.

Resistance welding is primarily a production welding process. It is especially designed for the mass production of domestic goods, automobile bodies, electrical equipment, hardware, etc. Probably the outstanding characteristics of this type of welding is its adaptability to raid fusion of seams.

Diesel engines

This text will describe the cylinder head in a diesel engine, and will give instructions on how to remote it.

The cylinder head is cast as one piece. It is the upper sealing surface of the combustion chamber. The valve guides, which guide the valve stem during the opening and closing of the valve, are pressed into the cylinder head. All cylinder heads are made of a special iron alloy casting containing carbon, silicon, and copper. This alloy mixture provides elasticity and good thermal conductivity, and has a low thermal expansion rate. The size of the cylinder head is not determined by the number of cylinders but rather by such factors as the overall cost of the engine, the cylinder block design, the number of main bearings, the expected thermal stress, and the anticipated cooling and sealing difficulties (of the cylinder head).

Removal of cylinder head

Care should be taken when removing the cylinder head bolts or nuts. Caution! Never remove the cylinder head when it is hot because it will become destroyed.

If the cylinder head is very heavy, use a hoist to lift it from the cylinder block. If it is small, screw the lift handles into the cylinder to lift it from the block.

Caution! When removing the cylinder head, take care not to damage it or the cylinder block surface or threads. If studs are used, take care not to bend them. After removal, place the cylinder head in a holding fixture, or if it happens to be square, you may place it on a workbench.

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Four-stroke engines

The engines of most cars operate on a four-stroke cycle. During the four strokes of this cycle, a piston moves down and up inside a cylinder. Valves help control the flow of fuel and air into the engine, and the flow of exhaust out of the engine. The first stroke of the cycle is the induction or intake stroke. In this, the intake valve is open and the exhaust valve closed. The piston moves down the cylinder, drawing in a fuel-air mixture. In the second strokecalled the compression stroke-both valves are closed. The piston moves up the cylinder,

The burning gases push the piston down for the power stroke. In final strokecalled the exhaust stroke-the intake valve is closed and the exhaust valve is open. The piston moves up the cylinder again, pushing the burned gases out.

Combustion engines

Combustion engines may be divided into types according to the duration of cycle on which they operate, in terms of piston strokes. By a cycle is meant the succession of operations in the engine cylinder which constantly repeats itself. The great majority of modern automotive engines operate on the fourstroke cycle, usually referred to as the Otto cycle, which is completed in four strokes of the piston, or during two revolutions of the crankshaft. Engines are also being built to operate on a cycle which is completed in two piston strokes. In this cycle a combustible gaseous mixture is compressed in the cylinder during the outward stroke of the piston, and burned and allowed to expand during the following inward stroke. Evacuation of the products, combustion and admission of a new-charge take place during the latter part of the expansion, and the early part of the compression stroke.

Diesel engines

Diesel Engines. In the diesel engine the latent energy of the fuel is transferred by being injected into a quantity of air compressed in a cylinder between the top of the piston and the underside of the cylinder head. The predetermined quantity of air is sucked into the cylinder through a valve in the cylinder top which then shuts, an upstroke of the piston compresses the air until it becomes as hot as red-hot iron, and this heat is sufficient to evaporate and ignite the charge of fuel which is injected through the spray nozzle (fuel injector) at the point of maximum compression. The resultant combustion drives the piston. Unlike gasoline engines, a diesel engine has no ignition system; it has no spark plug fed by electricity from an ignition distributor, spark coil, contact breaker and battery, or from a magneto. None of this is needed on a diesel engine because the fuel is ignited simply by contact with very hot air which has been

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highly compressed in the cylinder. Besides, a diesel engine draws into its cylinder air alone, and it compresses this air before any fuel enters the cylinder; a gasoline engine, on the other hand, mixes air with fuel in a carburetor outside the cylinder before it enters the engine. Diesel engines use less volatile, heavier liquid fuels than gasoline engines.

Two-stroke engines

Two-stroke engines with scavenging by combustible mixture are used only in small units (outboard engines, for example), and generally only in applications where the operation is quite intermittent. Their chief advantage is low first cost; their disadvantages are low fuel economy and lack of flexibility. A few engines have been built to operate on a six-stroke cycle, which has certain advantages where fuel of low volatility is to be used. Four of the six strokes of this cycle are used for the same operations as in the four-stroke cycle; during the remaining two strokes the combustible mixture is retained in the cylinder without being ignited, to give the fuel a better chance to vaporize and to diffuse uniformly throughout the air charge. Six-cycle engines have never reached a practical stage and of all of the high-speed combustion engines in use today that operate on volatile fuels, more than 99 per cent of the today horse power undoubtedly work on the four-stroke cycle.

Crawler cranes

Crawler Cranes, instead of having wheels, have a pair of treads made of steel plates linked together and driven by sprocket wheels. The weight is carried by a row of rollers on the lower frame. The width of tread plates and length of assembly make the unit bearing pressure so low than the crane can travel on soft, rough, or uneven ground, and it requires no track or mats. Crawler cranes are fitted with digging shovels, dragline buckets, trench hoes, skimmer buckets, etc., and can be converted easily from one to the other.

The Power Shovel is for general excavating, digging from the back, handling blasted rock, and for grading, including shallow cuts below grade. Its particular field is making cuts into and through banks, loading blasted rock on cars or trucks, where the machine stands in the hole or at base of the excavation. It can be used on loose piled materials, but if reach is long or lift high a grab bucket often works better.

The dragline crawler

The Dragline Crawler is for removing overburden, digging under water, cutting wide or deep trenches, and where it is necessary to work above material handled. Dragline excavators work outside the hole, and when fitted with long

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booms can cover a large area, pile material high, and load cars some distance away. The dragline bucket is not so well suited to side cutting as the trench hoe.

The Trench Hoe is used to dig trenches up to 12 ft. wide and 20 ft. deep in types of earth that can be cut and that will not cave in. It is faster than the dragline, can be more accurately controlled, and will cut a greater length of trench in a given time.

The Skimmer Bucket is a form of shovel comprising an open-end box with teeth. It travels back and forth on the underside of the crane boom and is used for grading, leveling, tearing up old pavements.

Разговорные темы

My speciality

I am a second-year student of the Belarusian-Russian University. I am going to become an engineer. Our graduates can work as production engineers or design engineers at industrial enterprises, design offices or research centers.

Design engineers design different machines, their components, special holding fixtures and tools and work out their operation principles.

Production engineers take the ideas of design engineers and make them into practical realities. Metal products may be large or small, simple or complex, and production engineers must decide what operations are to be performed to get the finished product. They specify the sequence of operations and what machine tools are required for each operation.

To cope with these tasks we must know the fundamentals of mathematics, mechanics, hydraulics, strength of material, to say nothing of special subjects.

We know that manufacturing today calls for a very high level of proficiency. We do our best to become really competent engineers.

Belarus

The Republic of Belarus is situated in the centre of Europe. It’s territory is 207.600 sq. km. The population of the country is about 11 million.

The climate of Belarus is continental. There are many rivers and lakes on the territory of the country. The main rivers are the Dnieper, the Pripyats and the Neman.

Belarus is rich in oil and peat resources.

If you look at the art and literature of Belarus you will find them comprehensive and rich.

To get a clear understanding of the life of any people you have to look back at its past.

In the years of World War I and during the Civil War Belarusian industry and agriculture were completely ruined.

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After the liberation in 1944 the restoration work began. Today Belarus is both young and old, beautiful and full of pride, independent and neutral, a country that is situates in the heart of Europe where all roads meet.

Great Britain

The United Kingdom of Great Britain and Northern Ireland occupies the greater part of the British Isles lying off the northwest coast of mainland Europe.

The country comprises England, Scotland, Wales and Northern Iceland. London (7 mln) is the capital of the country. The population of Great Britain is 57 mln people.

Britain has a generally mild, temperate climate. The weather is very changeable due to the influence of the sea.

British countryside is very varied and beautiful, it has mountains, rivers, many lakes.

Britain is one of the world’s major industrialized and trading nations, with an advanced communications and transport network.

Great Britain is a parliamentary democracy with a constitutional monarch. The House of Commons and the House of Lords, with the monarch, comprise the Parliament. There are two main political parties in Great Britain.

Great Britain has a long record of achievement in science and technology. Nobel prizes for science have been won by 70 British citizens.

My university

I am a correspondence student of the Belarusian – Russian University in Mogilev. The University was founded in 1961 as the Mogilev Mechanical Engineering Institute. It was transformed into the Mogilev State University in 2000, and in 2003 it became the Belarusian – Russian University.

Our University has 8 faculties, namely Automotive Engineering, Mechanical Engineering, Construction, Electrical Engineering Faculties, the Faculty of Economics, Pre-University Training and Professional Orientation Faculty, Correspondence Education and Foreign Students Faculties. They embrace 28 chairs and the Specialists Updating and Retraining Institute.

Students are trained in 13 specialties and 25 specializations. The student body is more than 5.000.

The studies are held in 5 buildings. The University has 3 Halls of Residence and a good library. 20 computer laboratories are equipped with up-to-date computers.

At present the BRU is the largest institution of higher technical education in Mogilev.

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Список литература

1 Андрианова, Л. Н. Курс английского языка для вечерних и заочных технических вузов /Л. Н. Андрианова, Н. Ю. Багрова. – М. : Высш.

шк., 2000.

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Приложение А

(рекомендуемое)

Таблица А.1 – Времена группы Indefinite Active

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Таблица А. 3 – Времена группы Perfect Active

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Таблица А.5 – Таблица форм причастий

Таблица А.6 – Синтаксические функции герундия в предложении и способы его перевода на русский язык

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Таблица А.7 – Форм герундия