II. Translate the passage into Ukrainian and ask all possible questions.

Chemical elements are metals or non-metals. They are widely used in making tools, instruments and devices. Metals and non-metals have different properties.

The combination of metals and non-metals is known as an alloy. For example, steel is an alloy of iron and carbon. The alloy of copper and zinc is known as brass. The properties of alloys are often better than the properties of their constituents. That is why the majority of engineering products are made of various alloys.

Further reading

I . Learn the following words and word-combinations to comprehend the text.

expansion	supply
environment	accelerator
change	torque
urban	gear-type
rural	emission
source	advantage
power	obstacle
inventor	volume
direct current	protect
alternating current	propel

II. Read and translate the text.

FUTURE SYSTEMS

Expansion of the total potential automotive market in the future and concern for the environment may be expected to change cars of the future. Special-purpose vehicles designed for specific urban or rural functions, with appropriate power system for each type of use, may be needed. Possibilities include electric, solar, steam, gasturbine, hybrid combinations, and other power sources.

Modern electric cars and trucks were manufactured in small numbers in Europe, Japan, and United States beginning in the 1980s.

However, electric propulsion is only possible for relatively short-range vehicles, using power from batteries of fuel cells. In a typical system, a group of lead-acid batteries, connected in a series, power electric AC induction motors to propel the vehicle. A solid state rectifier, or power inventor, changes the direct current supplied by the battery pack to an alternating current output that is controlled by the driver using an accelerator pedal to vary the output voltage. Because of the torque characteristics of the electric motors, conventional gear-type transmissions are not needed in most designs.

Compressed gas and blends derived from methanol and ethanol are being studied as fuels for the future because they may be produced from readily available biomass sources and have potential for high efficiency and lower emissions.

Gas turbines have been tested extensively and have good torque characteristics, operate on a wide variety of fuels, have high power-to-weight ratios, meet emission standards, and offer quiet operation. Some studies have shown that the advantages of the system are best realized in heavy-duty vehicles.

Nuclear energy offers the advantage of extremely low fuel weight. The obstacle for automotive use, however, is the great weight and volume of shielding required to protect the occupants from excessive nuclear radiating.

The advent during the 1990s of regulating requiring "zero emissions" from some vehicles in certain areas rekindled world interest in new battery technology. Battery system that offers higher energy density became the subject of joint research by auto industry scientists. Non commercial solar powered electric demonstration vehicles were built by universities and manufactures.

 

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