Найдите в тексте сказуемые в форме Present Perfect и объясните их употребление.

Найдите в тексте сказуемые в пассивном залоге и переведите их.

Задание V

1. Определите, какие из данных утверждений истинны, а какие ложны:

1. Materials science is relatively new scientific field.

2. Solid materials do not include polymers and semiconductors.

3. Ceramics are included in the group of nonmetallic elements.

4. Polymers are organic compounds that have very large molecular structures.

5. The electrical characteristics of semiconductors are extremely sensitive to minute concentrations of impurity atoms.

6. Biomaterials are always produced in laboratories using a variety of chemical approaches.

 

2. Ответьте на вопросы к тексту:

 

1. What activities are materials engineers involved in?

2. How are solid materials classified?

3. Why are metals extensively used in construction?

4. What are the advantages of ceramics?

5. What are the functions of biomaterials?

 

Задание VI

Выполните письменный перевод текста.

Выполните устный пересказ текста, используя необходимые фразы.

 

 

Unit 5

Задание I

1. Подберите русские эквиваленты к следующим словам, содержащим интернациональные корни:

 

Automobile, gas, cylinder, corrosion, nickel, vanadium, chromium, zinc, lithium, cable

2. Прочитайте следующий текст:

METALS

Metals are classified into ferrous metals that contain iron and non-ferrous metals that do not contain this element. Ferrous metals consist of iron combined with carbon, silicon, phosphorus and other elements. Pure metals are comparatively seldom used; in engineering, application is made chiefly of alloys which consist of two or more metals, or of metals and metalloids. Alloys are metallic solids, complex in composition, formed as a result of the freezing of the melt – the liquid solution of two or more metals, or metals and metalloids. Each constituent of an alloy is called a component. Alloys may be binary (two-component), ternary (three-component), etc. The ability of various metals to form alloys differs greatly and, therefore, the structure of various alloys after solidification may also be very diverse.

Carbon is the most important of all elements present in ferrous alloys. Ferrous metals are used in industry in two general forms; cast iron and steel, which differ in the quantity of carbon content. These two ferrous alloys are derived from pig iron which is produced in a blast furnace in the form of pigs. Metals are usually melted and poured into a form which is called a "mould". This process is known as casting. The cast metal is shaped in the mould where it cools and solidifies. Thus one can cast different objects known as castings. The shop where metals are cast is called a "foundry". Castings are used in building engines, automobiles and airplanes, and different types of machinery.

Cast iron is a general term applied to iron carbon alloys containing more than 1.7 per cent of carbon. Cast iron without the addition of alloying elements is weak in tension and shear, strong in compression and has low resistance to impact. It is obtained from the cupola furnace where pig iron is remelted in contact with coke. It is very cheap; in fact, it is the cheapest of all the engineering metals used in machine-building. Grey iron foundries are the most numerous because grey iron can be cast into almost any conceivable shape and size. Grey iron is also adapted to a great variety of castings, such as automobile, gas, steam, and hydraulic engine cylinders, bed plates for machines, car wheels, agricultural machinery parts, furnace and stove parts, water pipes, gears, and general machinery parts. The nature of the metal used for grey iron castings is such that castings can be made so hard that ordinary tool steel will not cut them or, on the other hand, so soft that they can, be readily machined. However, in comparison with other casting metals grey iron is weak and will not stand great shock. Hence, the engineer must allow a large factor of safety when specifying the use of grey iron castings, especially where great strength is required, or specify that the castings must be made from some other metal.

Steel is a ferrous material with a carbon content from 0.1% to 1.0%. Semisteel is a name to a metal made by melting 20 to 40 perсent of steel scrap with cast iron in the cupola. Steel castings are more expensive but stronger and tougher. Wrought iron is quite ductile and can be easily rolled, drawn, forged and welded. It has high resistance to corrosion. The carbon content is generally less than 0.1% and the material must contain not less than 1% slag. Cast steel normally contains about 0.5% of carbon, and is used to replace cast iron when castings of considerable strength are required. Forged steel is steel that has been hammered, drawn, pressed or rolled in the process of manufacturing of a particular part.

There are two general kinds of steels: carbon steel and alloy steel.

Carbon steel is known to contain only iron and carbon; while alloy steel contains some other “alloying elements” such as nickel, chromium, manganese, molybdenum, tungsten, vanadium etc.

Carbon steel seems to be the most common steels used in industry. The properties of these depend only on the percentage of carbon. Carbon steels are subdivided into groups.

Low carbon steels are very soft and are used for rails, bolts and for machine parts that do not need strength.

High carbon steel or “tool steel” may be hardened by heating it to a certain temperature and then quickly cooling in water. The more carbon the steel contains and the quicker cooling is, the harder it becomes. Because of its high strength and hardness this grade of steel is used for manufacturing tools and working parts of machines.

Alloy steels are known to have the following grades:

Special alloy steels, such as nickel steel, chromium steel are utilized for gears, bearings, shafts and wires. Alloying elements make these steels tougher, stronger and harder than carbon steels. Some

alloying elements cause steels to resist corrosion and such steels are called stainless steels.

High-speed steel (HSS) contains tungsten, chromium, vanadium and carbon. Tools made of high speed steel perform operations at much higher speeds than carbon steels.

Non-ferrous metals are more expensive than ferrous metals and are used only when some characteristic not possessed by iron or steel is essential or desirable in application. These characteristics are: high electrical and thermal conductivity, high corrosion resistance, non-magnetic qualities, light weight, etc.

The metals most frequently used to make non-ferrous metal castings are copper, tin, zinc, lead, nickel, gold, and aluminum. Some of the basic non-ferrous metals and their characteristics are described below. Copper is a reddish-brown, tough metal. It has very high electric conductivity and high corrosion resistant qualities. Copper is used for making electrical contacts and wires, pipes, telephone cables, tanks, water heaters, etc.

Zinc is a hard, brittle, bluish-white metal that is employed in the pure form as sheet zinc.

Lead is a very heavy bluish-grey metal which is yet soft. This metal is highly resistant to corrosion, but its strength is so low that it must be supported by a core of some other metal. Lead is used for lining pipes, acid tanks and coating electrical cables.

Aluminum is a soft, silvery white metal. It is light in weight, has high corrosion-resistant qualities and is used for automobile and airplane parts as well as for making different light-weight objects used in everyday life such as frames, cooking utensils, chairs, etc.

Tin is a silvery, corrosion-resistant metal. Tin is hardly used in pure form, but is employed as an alloying element.

Nickel is a hard, tough, silvery metal. It has high corrosion-resistant qualities and is used for plating other metals such as iron and brass.

The large family of non-ferrous metals offers a wider variety of characteristics and mechanical properties. For example, the lightest metal is lithium, 0.53 g/cm³, the heaviest, osmium, weighs 22.5 g/cm³ - nearly twice the weight of lead. Mercury melts at around – 38 ºF, and tungsten, the metal with the highest melting point, liquefies at 6,170 ºF.

Availability, abundance, and the cost of converting the metal into useful forms – all play important parts in selecting a non-ferrous metal. One ton of earth contains about 81,000 g of the most abundant metal of land, aluminum. One ton sea water, on the other hand, contains more magnesium than any other metal (about 1,272g). All sources combined, magnesium is the most abundant metal on the Earth. But because magnesium is difficult to convert to a useful metal, it may cost several times that of the least expensive and most easily produced metal, iron billet.

Although nearly 80% of all called “metals”, only about two dozen of these are used as structural engineering materials. Of the balance, however, many are used as coatings, in electronic devices, as nuclear materials, and as minor constituents in other systems.

3. Запомните необходимый минимум профессиональной лексики:

 

ferrous metal	черный металл
steel	сталь
pig	чушка
cast iron	чугун
casting	литье, отливка
foundry	литейный цех
mould	литейная форма
alloy	сплав
tension	напряжение, натяжение
cupola	вагранка
compression	сжатие
coating	покрытие
tungsten	вольфрам
resistance	сопротивление, устойчивость
strength	прочность, временное сопротивление материала
non-ferrous metal	цветной металл
copper	медь
lead	свинец

 

Задание II

1. Определите по формальным признакам, какой частью речи являются следующие слова, и переведите их:

Numerous, considerable, solidification, percentage, comparatively, abundance, nuclear, constituent

2. Определите значение префиксов и суффиксов в следующих словах и переведите их:

Metalloid, remelt, replace, subdivide, semisteel, stainless, bluish, silvery, useful

Задание III

1. Подберите эквиваленты к глаголам, обозначенным цифрами:

1. melt	a) отвердевать
2. pour	b) содержать
3. solidify	c) сокращать
4. resist	d) обладать
5. reduce	e) охлаждать
6. weld	f) заливать
7. cool	g) плавить
8. possess	h) использовать
9. employ	i) сопротивляться, выдерживать
10. contain	j) сваривать

2. Подберите эквиваленты к словосочетаниям, обозначенным цифрами:

1. доменная печь	a) stainless steel
2. чугун	b) melting point
3. сопротивление ударной нагрузке	c) thermal conductivity
4. жидкий раствор	d) resistance to impact
5. теплопроводность	e) blast furnace
6. нержавеющая сталь	f) cast iron
7. температура плавления	g) liquid solution

3. Составьте антонимичные пары:

1. light	a) heat
2. liquefy	b) tough
3. cool	c) freeze
4. melt	d) cheap
5. expensive	e) heavy
6. brittle	f) solidify

4. Соотнесите термины с их определениями:

1. casting	a) iron with a very little carbon content
2. alloy	b) a silvery, corrosion-resistant metal usually used as an alloying element
3. steel	c) a heavy bluish-grey metal with high resistance to corrosion and low strength
4. copper	d) the metal with the highest melting point
5. lead	e) a reddish-brown, tough metal with high electric conductivity
6. tungsten	f) a metallic solid formed as a result of freezing of the melt of two or more metals
7. tin	g) process of pouring melted metals into a mould

Задание IV