Plastics

Plastics are a large and varied group of materials consisting of combinations of carbon and oxygen, hydrogen, nitrogen, and other organic and inorganic elements. While solid in its finished state, a plastic is at some stage in its manufacture, liquid and capable of being formed into various shapes. Forming is most usually done through the application, either singly or together, of heat and pressure. There are over 40 different families of plastics in commercial use today, and each may have dozens of subtypes and variations.

A successful design in plastics is always a compromise among highest performance, attractive appearance, efficient production, and lowest cost. Achieving the best compromise requires satisfying the mechanical requirements of the part, utilizing the most economical resin or compound that will perform satisfactorily, and choosing a manufacturing process compatible with the part design and material choice.

Most people have now outgrown the impression that plastics are low-cost substitute materials. Those that still view plastics as cheap and unreliable have not kept up with developments in polymer technology for the past ten years.

Many plastics did indeed evolve as replacements for natural products such as rubber, ivory, silk or wool, which became unavailable or on short supply. But the new materials did not necessarily replace the older ones permanently nor made them obsolete. In many cases, they met an increased demand that could not be met by the natural product alone.

Today’s engineering resins and compounds serve in the most demanding environments. Their toughness, lightness, strength, and corrosion resistance have won many significant applications for these materials in transportation, industrial and consumer products. The engineering plastics are now challenging the domains traditionally held by metals: truly load-bearing, structural parts.

2. Translate the following sentences paying attention to the functions of the Gerund.

1. Casting is a process of forming metal objects. 2. The open-hearth process is one of the most important methods of making steel. 3. Numerous methods have been developed for producing metal castings. 4. The test needed increasing the temperature of the molten metal. 5. There are some ways of obtaining high quality alloys. 6. After pouring, the molten metal is allowed to solidify in a mold. 7. Aluminium has a melting point of 658,7 С.

3. Translate the following word combinations and sentences; observe the prepositions.

a) in building; in melting; on heating; on completing; on melting; by introducing; without employing; without machining

b) In building new metallurgical works, engineers have to solve many different problems. In melting steel, foundrymen use electric furnaces, crucible furnaces and converters. Liquids and gases expand on heating. On completing the construction, the cupola was tested in operation. Casting is a process of forming metal objects by melting metal and pouring it into molds. By introducing new foundry methods the engineers improve the quality of castings and the speed of manufacture. High-grade castings cannot be produced without employing electric furnaces. Most castings cannot be employed as parts of complex mechanisms without machining and finishing.

4. Translate the following paying attention to the Gerundial Constructions.

1. We know of Newton’s having developed principles of mechanics. 2. Mankind is interested in atomic energy being used only for peaceful purposes. 3. We know of Ukrainian metallurgical industry having made a great progress. 4. We speak about cupolas being used for melting cast iron. 5. Great attention is paid to the metal being heated to the proper temperature. 6. That sand molds are the oldest methods for producing metal castings is a well-known fact. 7. Melting may be done in cupolas, air furnaces, electric furnaces, etc. 8. Some metals require treatment before being placed in the melting furnace. 9. Carrying molten metal is usually performed in crane ladles. 10. The most favourable characteristic of a sand casting is its retaining good strength at moderately elevated temperature. 11. Melting is very important in the production of high-quality castings. 12.We know of electric furnaces being used for the production of high-grade castings. 13. A foundry cannot operate without employing proper foundry materials.

5. Translate into Ukrainian paying attention to the “ing-forms”.

1. Heating the gas increases the speed of the molecules. 2. Having made the experiment, the research engineer recorded the data. 3. Translating from one language to another we can use electronic computers. 4. Translating from one language to another has been accomplished by an automatic computer. 5. The failure was due to the operator’s having been careless in using the instrument. 6. The cupola is the most generally used melting process for cast iron, the fuel economy being highest and ease of manipulation greatest. 7. The Bessemer converter is used in steel making. 8. Cupola melting is continuous. 9. All non-ferrous alloys having a lower melting temperature than iron alloys are melted in crucible furnaces, open-flame furnaces and electric furnaces.

6. Find “ing-forms” in the text and insert them into the table.