9. Translate the following sentences

1. The students are alanyzing this equation now. 2. This equation is being analyzed now. 3. This discovery is much spoken about. 4. This article will be referred to. 5. By the end of this year the students will analyze this problem. 6. This problem has been already solved. 7. Our plant has been producing this equipment since 1975. 8. New equipment has been put into operation. 9. The teacher was explaining this rule when the bell rang. 10. This reaction has been considered during the work in the laboratory. 11. The students had been writing the test for half an hour when the dean entered the room. 12.The test had been already done by all the students when the dean entered the room.

10. Speak about the scientific research work of students of your department

UNIT23. SOLAR POWER

1. Memorize the following words:

to manifest – роботи очевидним, виявляти

solar – сонячний

to mean- означати, мати на увазі

crude – сирий, необроблений

selenium – селен

surface – поверхня

angle – кут, точка зору

absorptivity – абсорбуюча, поглинаюча спроможність

precaution – застереження

transparent – прозорий, ясний, зрозумілий

opaque- непрозорий, темний

2. Translate the following international words without a dictionary

Theory, generate, energy, scientists, electromagnetic, apparatus, thermal, electricity, meter, distance, experiment, engineering, selenium, convection, distillation, existence

3. Read and translate the text:

The sun's energy manifests itself as thermal, photo-electric and photo-chemical effects. Men have tried to use solar energy since earliest times, but no means existed to generate useful power from the sun's heat until steam and hot-air engines were invented.

Crude devices for heating water by solar energy date back many years, and production of salt by solar evaporation of sea water is probably the most ancient of man's sun-activated processes. Photo-electricity has been known for almost a century, and millions of selenium photo-cells have been used as light-meters and in a similar application.

Most fundamental of all thermal solar processes is the simple fact that, when sunlight falls upon a surface of any kind, the surface becomes warmer than the surrounding air. The extent to which the surface temperature rises depends upon many factors, most important of which are the angle between the surface and the sun's rays, the absorptivity of the surface and the precautions taken to prevent the surface from losing the absorbed heat

The angle effect is caused by the fact that the sun's rays travel in straight lines. When a surface is perpendicular to the rays, their intensity is at its maximum; the surface being horizontal, the radiation intensity drops off and reaches its minimum.

The most effective way to minimize the loss of energy from the sun heated surface is to cover it with one or more sheets of a glass-like material which is transparent to the sun's rays but opaque to the longer wave lengths emitted by the warmed surface The air space between the surface and the glass is an effective prevention of heat loss by convection.

A flat plate of blackened metal covered with one or more transparent sheets of glass or plastic is known to be the simplest collector of solar energy. Once collected, heat can be used in a variety of ways. Here are some of the potential and actual applications.

Space heating is probably the most important, since nearly one-third of our energy supply is used for this purpose Water heating can be achieved by portable solar heaters which are able to give as much as 400 litres of boiling water on a sunny day.

The distillation of sea water is another process to be accomplished by variations of the simple flat plate collector. The production of temperatures low enough for air conditioning and domestic refrigeration is a very important potential use of solar energy which is only now beginning to receive the attention it deserves.

Typical arrangements of concentrator-type solar plants with high-pressure boilers must be able to track the sun, so that its rays can be focused upon a collection-element.

Physicists generate electricity directly from radiation, using both nuclear and solar power. Until that time solar units will probably continue to be relatively small and applicable only to special purposes such as irrigation and power production in isolated locations.

We believe solar radiations to be a great source of energy our world possesses. Research is needed now to learn how to use solar energy cheaply and effectively to heat and cool our homes, produce fresh water from sea water, and to generate large blocks of electric power.