TEXT 9. Automobile production

Specialists in automobile industry deal with designing and manufacturing of cars and trucks. In this way they should know that the overall production of an automobile comprises the following phases:

1. Designing (i.e. creating the project which is to be brought to life in full accordance with public and industrial needs and technical and ecological requirements).

2. Working out the technology of manufacturing processes, including strategic planning and plant premises layout.

3. Laboratory tests (at the plant or in specially organized test centers which are cosponsored by different businesses).

4. Road tests (practical field running of ready machine elements and completely assembled units).

5. Mass production (manufacturing) and further marketing of the ready-made production.

It is important to know them, as before the automobile (car or truck) is put into mass production, it should be properly designed and the automobile must meet up-to-date requirements. And what are these requirements? The automobile must have high efficiency, long service life, driving safety, ease of maintenance and pleasant appearance. In order to obtain all these qualities, engineers should develop advanced methods of designing cars, using new types of corrosion resistant light materials. Also, it is important to know computer science and IT, because it is intended to shorten the time between designing and manufacturing. Computers offer quick and optimal solutions of these problems.

But before the car is put into mass production, all its units and mechanisms are subjected to tests, first in the plant laboratory, and then the car undergoes a rigid quality control in road tests. Only then the car is put into mass production. Why are these tests required? What qualities are required of the automobile? The modern automobile must be rapid in acceleration, must have a smooth acting clutch, a silent gearbox, dependable brakes and steering system, as well as pleasant appearance. It also must be comfortable and have all conveniences.

TEXT 10. Electric current

The electric current is a quantity of electrons flowing in a circuit per second of time. The unit of measure for current is ampere. If one coulomb passes a point in a circuit per second then the current strength is 1 ampere. The symbol for current is I. The current which flows along wires consists of moving electrons. The electrons move along the circuit because the e .m. f. drives them. The current is directly proportional to the e. m. f. In addition to traveling through solids, however, the electric current can flow through liquids as well and even through gases. In both cases it produces some most important effects to meet industrial requirements.

Some liquids, such as melted metals for example, conduct current without any change to themselves. Others, called electrolytes, are found to change greatly when the current passes through them. When the electrons flow in one direction only, the current is known to be d. c., that is, direct current. The simplest source of power for the direct current is a battery, for a battery pushes the electrons in the same direction all the time (i.e., from the negatively charged terminal to the positively charged terminal).

The letters a. c. stand for alternating current. The current under consideration flows first in one direction and then in the opposite one. The a. c. used for power and lighting purposes is assumed to go through 50 cycles in one second. One of the great advantages of a. c. is the ease with which power at low voltage can be changed into an almost similar amount of power at high voltage and vice versa. Hence, on the one hand alternating voltage is increased when it is necessary for long-distance transmission and, on the other hand, one can decrease it to meet industrial requirements as well as to operate various devices at home.

Although there are numerous cases when d. c. is required, at least 90 per cent of electrical energy to be generated at present is a. c. In fact, it finds wide application for lighting, heating, industrial, and some other purposes.