CONTROL WORK № 2, Variant 2 (FIBERS)

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CONTROL WORK № 2, Variant 2 (FIBERS)


CONTROL WORK № 2
Variant 2
READING
Text 1
1. Read the text about some properties of materials. For questions 1–10, decide if they are true (T) or false (F).
PROPERTIES OF MATERIALS
The properties of materials are sometimes referred to as structuresensitive, as compared to structure-insensitive properties. In this case structure-insensitive properties include the traditional physical properties: electrical and thermal conductivity, specific heat, density, and magnetic and optical properties. The structure-sensitive properties include the tensile and yield strength, hardness, and impact, creep, and fatigue resistance. It is recognized that some sources maintain that hardness is not a true mechanical property, because it varies somewhat with the characteristics of the indenter and therefore is a technological test. It is well known that other mechanical properties vary significantly with rate of loading, temperature, geometry of notch in impact testing, and the size and geometry of the test specimen. In that sense all mechanical tests of material properties are technological tests. Furthermore, since reported test values of materials properties are statistical averages, a commercial material frequently has a tolerance band of ±5 percent or more deviation from a given published value.
In the solid state, materials can be classified as metals, polymers, ceramics, and composites. Any particular material can be described by its behavior when subjected to external conditions. Thus, when it is loaded under known conditions of direction, magnitude, rate, and environment, the resulting responses are called mechanical properties. There are many possible complex interrelationships among the internal structure of a material and its service performance. Mechanical properties such as yield strength, impact strength, hardness, creep, and fatigue resistance are strongly structure-sensitive, i.e., they depend upon the arrangement of the atoms in the crystal lattice and on any imperfections in that arrangement, whereas the physical properties are less structure-sensitive. These include electrical, thermal, magnetic, and optical properties and do depend in part upon structure; for example, the resistivity of a metal increases with the amount of cold work.
Physical properties depend primarily upon the relative excess or deficiency of the electrons that establish structural bonds and upon their availability and mobility. Between the conductors with high electron mobility and the insulators with no free electrons, precise control of the atomic architecture has created semiconductors that can have a planned modification of their electron mobility. Similarly, advances in solid-state optics have led to the development of the stimulated emission of electromagnetic energy in the microwave spectrum (masers) and in the visible spectrum (lasers).

STATEMENTS    T/F
1. The structure-sensitive properties include the tensile and yield strength.    
2. The structure-insensitive properties don’t include electrical and thermal conductivity.    
3. Hardness is a true mechanical property.    
4. In the solid state, materials cannot be classified as metals.    
5. There are a lot of possible complex interrelationships among the internal structure of a material and its service performance.    
6. Mechanical properties are strongly structure-sensitive.    
7. Physical properties are less structure-sensitive.    
8. The resistivity of a metal decreases with the amount of cold work.    
9. Physical properties don’t depend on the excess of the electrons.    
10. Semiconductors can have a planned modification of their electron mobility.    

Text 2
2. Read the text about one of the inventors of the world James Watt. For questions 1–6, choose the best answer А, В, C or D.
JAMES WATT
James Watt was born in Greenock, Scotland, and was taught at home. Later he went to Greenock Grammar School. His technical expertise seems to have been obtained from working in his father’s work – shop and from early in life he showed academic promise. His early formal training was as an instrument maker in London and Glasgow. Watt combined the expertise of a scientist with that of practical engineer and later he was not only to improve the heat engine but also to invent new mechanisms. Watt was interested in making experimental models of steam engines and this marks a historical milestone in engineering development, for they were the first experimental apparatus purposely constructed for engineering research. Watt’s early interest in steam arose from experience in repairing a model steam engine in 1764, and in 1765 he invented the separate steam condenser. In 1769 he took out a patent on the condenser in which steam came into direct contact with cold water. That was a milestone by which steam engineering reached its practical and usable form. In 1784 he took out another patent for a reaction turbine at a time when continental engineers were only considering similar approaches. An improved centrifugal governor was to follow in 1788 and a design for a pressure gauge in 1790. In the development of the steam engine James Watt represents the perfecting of a sequence of stages beginning with the Newcomen engine and ending with the parallel motion and sun/planet gearing. The latter is said to have been invented by W. Murdock but patented by Watt. In the scientific field Watt’s finest memorial, apart from steam engines, is his establishment of the unit of power – the rate of doing work. He introduced the term horsepower (hp), one horse being defined as equivalent to 33,000 ft lb/mm. James Watt died in 1819 in Heathfield, after a life of incomparable technical value. Later, a statue to Watt was placed in Westminster Abbey.

1. James Watt was born in ______.
A. Scotland
B. England
C. Wales
D. Northern Ireland
2. When a child he went to ______ school.
A. Comprehensive
B. Grammar
C. Technical
D. Humanitarian
3. James Watt invented the separate steam condenser in ______.
A. 1764
B. 1765
C. 1769
D. 1784
4. In 1784 he took out another patent for a reaction turbine at a time when ______.
A. he combined the expertise of a scientist with that of practical engineer
B. he was repairing a model steam engine
C. he was making experimental models of steam engines
D. continental engineers were considering similar approaches
5. Sun/planet gearing was invented by ______.
A. H. Davy
B. W. Murdock
C. J. Watt
D. I. Newton
6. James Watt died in ______.
A. Heathfield
B. Greenock
C. Westminster
D. Glasgow

VOCABULARY AND GRAMMAR
3. Choose the correct item A, B, C or D.
1. Mechanical behavior under load can be explained ______ impurities.
A. in case of
B. because of
C. in terms of
D. due to
2. The procedures are used to modify the mechanical ______ of particles.
A. behavior
B. tendency
C. direction
D. position
3. Other engineers have to deal ______ microscopic properties.
A. in
B. out
C. with
D. up
4. From early in life Watt showed academic ______.
A. subjects
B. sciences
C. promotions
D. promise
5. Watt was interested in ______ experimental models of steam engines.
A. collecting
B. making
C. doing
D. gathering
6. If we changed the rate of loading, the mechanical properties ______ vary.
A. will
B. would
C. don’t
D. doesn’t
7. The resistivity of a metal ______ unless the amount of cold work is little.
A. increase
B. increased
C. increases
D. have increased
8. If the engineers ______ new approaches, they wouldn’t have taken out another patent for a reaction turbine.
A. won’t consider
B. don’t consider
C. didn’t consider
D. hadn’t considered
9. His interest in steam ______ if he hadn’t repaired a model steam engine.
A. wouldn’t have arisen
B. didn’t arise
C. doesn’t arise
D. won’t arise
10. In 1765 he invented the separate steam condenser, ______?
A. wasn’t he
B. isn’t it
C. didn’t he
D. didn’t it

TRANSLATION
4. Translate the sentences from Russian into English.
1. Механические свойства металлов зависят от их структуры.
2. К основным физическим свойствам вещества относится, например, электрическая и термальная проводимость.
3. В этом смысле все механические испытания являются технологическими испытаниями.
4. Вещества, находящиеся в твердом состоянии, классифицируются как металлы, полимеры, керамика.
5. От чего зависят физические свойства материалов?
6. Джеймс Уатт интересовался созданием экспериментальных моделей паровых двигателей.
7. Он не только усовершенствовал тепловой двигатель, но и также изобрел новые механизмы.
8. Джеймс Уатт получил патент на конденсатор, в котором пар вступал в прямой контакт с холодной водой.
9. Это были первые экспериментальные аппараты, специально созданные для инженерных исследований.
10. Кроме паровых двигателей, он установил единицу мощности.

WRITING
5. Write an abstract to the following text. The length of the abstract is 100–120 words (see Appendix).
FIBERS
Fibers are probably the oldest engineering materials used by man. Jute, flax, and hemp have been used for “engineering” products such as rope, cordage, nets, water hose, and containers since antiquity. Other plant and animal fibers have been used for felts, paper, brushes, and heavy structural cloth. The fiber industry is clearly divided between natural fibers (from plant, animal, or mineral sources) and synthetic fibers. Many synthetic fibers have been developed specifically to replace natural fibers, because synthetics often behave more predictably and are usually more uniform in size. For engineering purposes, glass, metallic and organically derived synthetic fibers are most significant. Nylon, for example, is used for belting, nets, hose, rope, parachutes, webbing, ballistic cloths, and as reinforcement in tyres.
Metal fibers are used in high-strength, high-temperature, lightweight composite materials for aerospace applications. Fibers composites improve the strength-to-weight ratio of base materials such as titanium and aluminum. Metal-fiber composites are used in turbine compressor blades, heavy –duty bearings, pressure vessels and spacecraft reentry shields. Boron, carbon, graphite, and refractory oxide fibers are common materials used in highstrength fiber composites.
Glass fibers are probably the most common of all synthetic engineering fibers. These fibers are the finest of all fibers, typically one to four microns in diameter. Glass fibers are used for heat, sound, and electrical insulation; filters; reinforcements for thermoplastics and thermoset resins and for rubber (such as in tyres); fabrics, and fiber optics.