Vocabulary:

Machine-tools – станки,workpiece –деталь, якуобробляють, facility – пристрій,thread(to) – різьба, нитка, нарізка,screw– винт, навинчувати, discharge– розряд, feed (fed, fed)– подавати, подача, lathe– токарнийстанок, friction– тертя, flexible– гнучкий, to mount– кріпити, прикріпляти, close tolerance – жорсткий допуск

Machine-tools are used to shape metals and other materials. The material to be shaped is called the workpiece. Most machine-tools are now electrically driven. Machine-tools with electrical drive are faster and more accurate than hand tools: they were an important element in the development of mass-production processes, as they allowed individual parts to be made in large numbers so as to be interchangeable.

All machine-tools have facilities for holding both the workpiece and the tool, and for accurately controlling the movement of the cutting tool relatively to the workpiece. Most machining operations generate large amounts of heat, and cooling fluids (usually a mixture of water and oils) must be used for cooling and lubrication.

Machine-tools usually work materials mechanically but other machining methods have been developed lately. They include chemical machining, spark erosion to machine very hard materials to any shape by means of a continuous high-voltage spark (discharge) between an electrode and a workpiece. Other machining methods include drilling using ultrasound, and cutting by means of a laser beam. Numerical control of machine-tools and flexible manufacturing systems have made it possible for complete systems of machine-tools to be used flexibly for the manufacture of a range of products.

Lathe is still the most important machine-tool. It produces parts of circular cross-section by turning the workpiece on its axis and cutting its surface with a sharp stationary tool. The tool may be moved sideways to produce a cylindrical part and moved towards the workpiece to control the depth of cut. Nowadays all lathes are power-driven by electric motors. That allows continuous rotation of the workpiece at a variety of speeds. The modern lathe is driven by means of a headstock supporting a hollow spindle on accurate bearings and carrying either a chuck or a faceplate, to which the workpiece is clamped. The movement of the tool, both along the lathe bed and at right angle to it, can be accurately controlled, so enabling a part to be machined to close tolerances.

Ex. 15. Match the Words:

1. facility	А. гвинт
2. feed	В. зсередини
3. flexible	С. гнучкий
4. friction	D. діапазон
5. inside	Е. допуск
6. outside	F. закріплювати
7. range	G. колесо
8. screw	Н. деталь, що обробляють
9. sharp	I. гострий
10. thread	J. подача
11. to allow	К. дозволяти
12. to lubricate	L. пристрій
13. to mount	М. різьба
14. to remove	N. змащувати
15. to require	О. ззовні
16. tolerance	Р. вимагати
17. wheel	Q. тертя
18. workpiece	R. видаляти

Ex. 16. Answer the questions:

1. What are machine-tools used for?

2. How are most machine-tools driven nowadays?

3. What facilities have all machine-tools?

4. How are the cutting tool and the workpiece cooled during machining?

5. What other machining methods have been developed lately?

6. What systems are used now for the manufacture of a range of products without the use of manual labour?

7. What parts can be made with lathes?

8. How can the cutting tool be moved on a lathe?

9. How is the workpiece clamped in a lathe?

10. Can we change the speeds of workpiece rotation in a lathe?

11. What is numerical control of machine tools used for?

Ex. 17. Find English equivalents in the text:

1. матеріал, що обробляють

2. електропривід

3. більш точний

4. окремі деталі

5. процес масового виробництва

6. пристосування для тримання різця і деталі

7. операції з механічної обробки деталі

8. високовольтний розряд

9. свердління ультразвуком

10. різання за допомогою лазерного променя

11. гнучкі виробничі системи

12. деталі круглі у розрізі

13. повертати деталь навколо її осі

14. рухати в бік, рухати у напрямку до деталі

15. глибина різання

16. безперервне обертання деталі

17. рухрізцявздовжстанини

Ex. 18. TranslateintoEnglish:

1. Токарний верстат дозволяє виробляти деталі круглі у розрізі.

2. Деталь затискається в патроні або на планшайбі токарного верстата.

3. Різець може рухатися як уздовж станини, так і під прямим кутом до неї.

4. Сучасні токарні верстати часто мають цифрове управління.

Unit 15

Text A.: Mercury in the Environment Text B. Milling Machine Grammar: The Subjective Infinitive Construction

Text A

MERCURY IN THE ENVIRONMENT

Notes on the Text

one part per million – одна частина на мільйон

on a substantial scale – у великих масштабах

toamountto – складати; дорівнювати; досягати

Mercury is known to be a rare element. The element is found in trace amounts throughout the lithosphere (rocks and soil), the hydrosphere, the atmosphere and the biosphere (in tissues of plants and animals).

In the rocks and soil mercury is found to be measured in fractions of one part per million. In the hydrosphere (the seas and fresh waters) it occurs only in parts per billion. In the atmosphere mercury is present both as vapour and in the form of particles.

It should be noted, however, that under natural conditions the amount of mercury in the atmosphere is so smallthat extremely sensitive methods are required for detectingand measuring it. The situation is somewhat different in the biosphere. Plants and animals tend to concentrate mercury. For example, it has been found some marine algae to contain a concentration of mercury more than 100 times higher than thatin the seawater in which they live.

Mercury today is used on a substantial scale in chemical industries, it being used in the manufacture of paints and paper as well as in agriculture. The world production of mercury has been found to amount to about 10,000 tons per year. In agriculture, mercury in the form of corrosive sublimate (HgCl₂) can be used for disinfecting seeds. The chlorides of mercury are employed in protecting a number ofvegetable crops.

Due to such large-scale uses a considerable amount of mercury waste is likely to flow into the air, the soil, the streams, rivers, lakes. One might ask whether all these may present a threat to health?

In order to answer this question it is necessary to examine the forms in which mercury occurs. Liquid mercuryitself is not toxic to man, but mercury vapour, however,can be injurious. The soluble inorganic salts of mercury have long been known to be toxic.

So, knowing properties and forms of mercury it is possible to use it.

Mercury being very important, it is useful to continue investigating its properties very closely.

Properties of Mercury.

Mercury is unusual in that it is the only metal, which is stable in the liquid state at about 20°C. It has a bright silvery luster, shows little tendency to tarnish at ordinary temperature, it being a good conductor of both heat and electricity.

Because of its uniform expansion over a wide range of temperature, it is well adapted to use in thermometers, and due to its high density, low coefficient of expansion, and slight vapour pressure at ordinary temperature it is well suited for using in the liquid type barometer.

Despite having high boiling point, mercury does show a small vapour pressure even at ordinary temperatures.

Being raised to a temperature above its boiling point, mercury vapour readily conducts electricity at the same time emitting radiation, it being rich in ultraviolet rays.

Ex. 1. Answer the following questions:

1. Where can mercury be found? 2. What methods are required to detect the presence of mercury in the atmosphere? 3. Where is mercury used? 4. In what form is mercury used in agriculture? 5. What is mercury used for in agriculture? 6. Why is mercury considered to be unusual metal? 7. What properties of mercury do you know? 8. Why can mercury be used in thermometers and barometers? 9. When does mercury conduct electricity?

Ex. 2. Translate the following sentences paying attention to the words in bold type;

1. By close study they could learn that the vapours of this substance are dangerous. 2. The similarity of mercury to zinc and cadmium is not very close, the metal showing a greater similarity to copper and silver. 3. Close the test tube until the solution cools. 4. The elements of Group II-B and IV -B of the Periodic System closely resemble the elements of Group III and IV respectively. 5. One degree is the one hundredth part of the temperature range between the normal freezing and boiling points of water. 6. The ⁶Li content of samples encountered in this laboratory has rangedfrom4 to 98%. 7. The amount of water was not enough to carry out this experiment. 8. It should be noted that the increase in temperature amounted to only 20°C.

Ex.3. Explain the meaning of the verb "to do" in the following sentences:

1. The old methods of carrying out such experiments should be done away with. 2. What do you usually do in the laboratory? 3. He will do his best to finish his work in time. 4. Among the gases with which mercury does react is hydrogen sulphide. 5. Being lower than hydrogen in the activity series mercury does not displace hydrogen from solution but it does react with the oxidizing oxides to form their respective salts. 6. The substance does support combustion. 7. While no exchange takes place between chloride bromate and the corresponding halogen in neutral solutions exchange does occur if the solution is acidified. 8. Gold does not combine with oxygen or with sulphur and does not react with any familiar acids. It does, however, combine with chlorine and bromine. 9. Copper does not displace hydrogen from acids, but does react with acidic oxidizing agents. 10. They did carry out this work in due time. 11. Despite its high boiling point, mercury does show a small vapour fifessure even at ordinary temperature. 12. They did their task very well though it was rather difficult. 13. They always do everything in due time. 14. Do you know that a quite new property of this substance was observed? 15. I'll do my best to study well.

Grammar

The Subjective Infinitive Construction

He

is known

to go to work to Siberia.

Passive Voice to know, to think,to consider, to believe, to suppose, to expect, to imagine, to find, to trust, to assume	He is known to work in the field of nuclear physics. He is believed to have carried out a number of tests. This problem is expected to have been solved. This question is supposed to be solved soon. He is known to be preparing for his exams.
to make	Little Bob was made to put on some warm clothes.
to say, to report , to state	He is said to have gone to work to Poland.
Active Voice to seem, to happen, to prove, to be likely, to be unlikely, to be sure, to be certain, to turn out.	They are unlikely to come in time. He is likely to be in the laboratory. She is unlikely to know him. He proves to work at this problem The work proved to be useful. They proved to have examined this substance. She seemed to have completed her tests. They seemed to have forgotten him. They seemed to be interested in this work. She appeared to deal with this branch ofchemistry. He appeared to have attended the lecture. This turned out to be very simple. He happened to have taken part in the discussion.

Ex.4. Compare the following pairs of sentences, and translate them:

The article appeared in our magazine yesterday. The article appeared to be very interesting.

He proved this phenomenon tentatively. He proved to know this law.

Ex. 5. Paraphrase the following sentences using the Subjective Infinitive Constructions as in the models:

Model I: It is known that he will make his report ^: today.

He is known to make his report today.

1. It is believed that the method involved is good. 2. It is expected that they will take part in this research work. 3. It is known that evaporation goes more rapidly at the higher temperature. 4. It was known even in ancient times that water is denser than air.

Model II: It was found that those rays had been deflected.

Those rays were found to have been defleeted.

1. It was known that the substance had been purified. 2. It was considered that the method had been improved. 3. It was known that the investigations carried out by him had resulted in new discoveries. 4. It is believed that they have examined this substance sufficiently.

Model III: It appears that he has passed all his exams very well.

He appears to have passed all his exams very well.

1. It seems that they have already purified the substance. 2. It appears that the iron rod has been rusted. 3. It happened that the method had been unsuitable. 4. It happened that he had discovered some new and very interesting properties of this element. 5. It seemed that the temperature had been raised. 6. It is likely that they have translated the article.

7. It happened that they had carried on their research simultaneously. 8. It seemed that this solution was more concentrated.

Ex. 6. Combine the sentences using the Subjective Infinitive Construction as in the model:

Model: He has graduated from the Institute. I know it.

He is known to have graduated from the Institute.

1. M. Curie discovered radium. Everybody knows that. 2. He has finished his work. They said to us about it. 3. They work in the laboratory of organic chemistry. We know that. 4. The meeting will take place in our club. We were informed about it. 5. She has passed all her exams well. I know it.

Ex. 7. Compare the following pairs of sentences, translate them:

1. The science of chemistry is known to deal with substances.

We know the science of chemistry to deal with substances.

2. Every crystal has been found to consist of atoms arranged in a three-dimensional pattern. They have found every crystal to consist of atoms arranged in a three-dimensional pattern.

3. Wilhelm Konrad Rontgen is known to have discovered a new kind of rays which he called X-rays.

Everybody knows Wilhelm Konrad Rontgen to have discovered a new kind of rays which he called X-rays.

4.Helium atom was stated to contain two electrons both of which are held tightly.

The scientists stated helium atom to contain two electrons both of which are held tightly.

5.The substance concerned is supposed to have been prepared by the reaction of some metals with water.

The scientists suppose this substance to have been prepared by the reaction of some metals with water.

Ex. 8. State the functions of the Infinitives and translate the following sentences:

1. At least three of the remaining four particles are needed to account for the observed relationships. 2. This substance was purified to investigate its properties carefully. 3. Lead is known to be a bright silvery metal with a pronounced bluish colour. 4. The radiation was first thought to consist of gamma-rays, but the energy relationships were found to disagree with this assumption. 5. They proved soluble lead salts to be poisonous. 6. They have been told to examine all the found precipitates. 7. The laboratory appeared to have been equipped very well. 8. The sediment to be investigated appeared on the bottom of the flask. 9. They are likely to have proved this solvent to be very volatile. 10. They were asked to find out all the constituents of the compound. 11. A series of experiments was conducted to determine the effect of adding this element.

Ex.9. Find the sentences with the Subjective Infinitive Construction. Translate the sentences:

1. The new method appeared to be very tedious and time-consuming. 2. The atoms of unconfined elements proved to be electrically neutral. 3. Elements composed of atoms containing only one or two valence electrons prove to form positive ions by giving up electrons during their reactions. This new element has been discovered to be very useful. They knew this new element to have been discovered and used. 6. The concentration of the solute particles seems to be less than an integral multiple of the molecular concentration. 7. The question known to be very important will be discussed very scon. 8. Many of the substances determined to be soluble will be carefully investigated. 9. Zinc and cadmium are used widely to protect iron and steel from rust. 10. The concentration of chromate ions required to establish this condition may be secured through the use of a weakly acidic solution of potassium chromate. 11. During the burning of coal there appears to be a loss of weight. 12. No single set of properties is sufficient to serve for the definition of matter. 13. The changes reported to take place are shown in this table. 14. These changes were found to follow certain rules. 15. The particles shown to be negatively charged were used in this device. 16. The Beta rays were shown to be negative particles. 17. The element helium is known to have been discovered in the sun. 18. Organic chemistry is known to be defined as the chemistry of compounds containing carbon. 19. The experimenter knew this substance to be absolutely pure.

Ex. 10. Translate the following sentences paying attention to the Subjective infinitive Constructions:

1. The solubility of helium is stated to be much less than that of nitrogen. 2. Argon appears to be widely used for filling electric light bulbs. 3. The spectrum of the gas has been found to be the same as that observed before. 4. The amount of this substance was considered to have been of no practical importance. 5. Natural gas proves to contain a small percentage of argon. 6. This gas is stated to have found wide application in medicine. 7. These analyses turned out to have been of great importance for our research. 8. Our research-workers are reported to have finished their invest1gations in time. 9. Some materials are found to become readily charged and to hold their charges, while others are known to lose their charges very quickly.

Ex. 11. Translate the following sentences, mind the Infinitives:

1. The copper to be used for electrical purposes must be extremely pure. 2. Many food products are known to be imported to Britain. 3. The iron ore in England is found to be low grade. 4. Iron to be protected from rust should be coated by zinc or cadmium. 5. Their task was to find out all the properties of this element. 6. We know the majority of the population of Britain to live in towns. 7. Metals, which corrode easily, are to be protected with a film of copper. 8. We expect them to have visited many cities of our country.

Text B

MILLING MACHINE