Ex.2: Translate the words given below, paying attention to different suffixes and prefixes:
conduct, conductor, conductivity; resist, resistant, resistance; pass, passage, passing; apply, application, applicable; advantage, advantageous, disadvantage; rapid, rapidly, rapidity; move, moving, movement; usual, usually, unusual; important, importance; part, partly; wood, woody, wooden; treat, treatment.
Ex.3: State the part of speech of the underlined words and translate the sentences.
1. The ability of a substance to resist the passage of heat and electricity is of great importance.
2. Dry wood is a poor conductor of heat.
3. It should be noted that the transmission of heat depends on the specific conductivity of the material.
4. The conduction of heat through wood is of great importance in the kiln - drying of timber.
5. The movement of heat is more rapid in green timber.
Ex. 4: Answer the following questions.
1. Is the heat conductivity of wood high or low?
2. Why is wood suitable for making handles of cooking utensils?
3. What does the transmission of heat depend on?
4. Why is the conductivity of dry wood lower than of green timber?
5. What wood conducts heat more rapidly: heavy and dense or light and porous one?
6. What process takes less time: drying boards in the open air or in a special kiln?
7. Is the temperature of the boards placed in the kiln measured?
8. What parts of boards being dried in a kiln are heated quicker: interior or exterior ones?
9. Who must take into account the properties of wood under heating?
Species of trees and their application.
In our rapidly changing cosmic age wood continues to serve mankind in different ways. In spite of many artificial materials having been created we still depend on wood and articles made of wood. If wood disappeared suddenly life would change greatly. How would our houses be furnished without lumber and veneer? Where should we get political, cultural and scientific information if there were no books and newspapers.
Raw materials from which lumber is produced are logs of a definite quality and size, belonging to different forest species. The logs are usually divided into three grades, the first two being used for high quality lumber.
An engineer of wood - working industry should know how to use wood in construction as well as for decorative purposes to the best advantage. Usually the valuable species are not used for making the bodies of articles. The article made of valuable species would be too heavy and too expensive. The body of an article is often made of cheap species and all the facing parts are covered with veneer of valuable species.
Different softwoods and hardwoods are used in cabinet making, beginning with the cheapest local species to the valuable expensive and rare ones. Many of them possess such properties as high durability, attractive color and pleasant odor.
Pine, for example, is the most widespread species in cabinet making. It is light in weight, cheap and grows in many localities. Its being knotty, resinous and hard for finishing is considered to be allowable defects. Doors, kitchen tables, banks and stools are usually made of pine.
Walnut is one of the most valuable species distinguished for its attractive grain figure, its density and adaptability to high quality finishing. Walnut is used for decorative purposes chiefly as veneer.
Oak, beech and mahogany are also mostly used for decorative purposes.
Exercises.
Ex.1: Translate the following words and remember them.
size, grade, weight, knot, resin, resinous, density, oak, beech, cheap, chief.
Ex.2: Translate the words given below, paying attention to different suffixes and prefixes: differ, different, difference; appear, disappear; inform, information; divide, division; advantage, advantageous, disadvantage; value, valuable, valueless; local, locality; odor, odorless; durable, durability; dense, density; apply, application; applicable; rapid, rapidity, rapidly; decorate, decorator, decorative; knot, knotty; resin, resinous; allow, allowable.
Ex.3: State the part of speech of the underlined words and translate the sentences.
1. In our rapidly changing cosmic age wood still find wide application.
2. If wood disappeared suddenly life would change greatly.
3. Wood is used in construction as well as for decorative purposes.
4. Many species of trees possess valuable properties such as high durability, strength and attractive colour.
5. Walnut is one of the most valuable species due to its high density and adaptability to high quality finishing.
Ex. 4: Answer the following questions.
1. Does wood serve mankind in different ways?
2. What articles made of wood can be found in every house?
3. Are books and newspapers considered to be a source of political and cultural information of the people?
4. What is paper produced from?
5. Into how many grades are logs usually divided?
6. What species are usually used for making the body of an article?
7. What parts of the article are covered with veneer of valuable species?
8. What species possess such properties as high durability, attractive colour and pleasant odor?
9. Where is pine used?
10. What is walnut distinguished for?
Fireproofing.
To prevent wood from fire some chemicals or paints are usually used. They are effective because they prevent combustion of the charcoal. It should be taken into account that they can't prevent chemical decomposition of the wood but they change the form in which this decomposition takes place. They may be called, therefore, fire - retardant substances. Treated with these substances wood becomes more fire - resistant and durable.
There exist three groups of fireproof substances.
The first group of chemicals melts at a temperature below that at which wood decomposes. These chemicals form a glaze over the surface of the wood, the glaze preventing access of oxygen to the wood. The second group of chemicals decomposes under heat, yielding non -inflammable gases. These gases dilute the inflammable gases of the decomposing wood and form a non - inflammable mixture.
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