Timber. Wood formation. Wood structure. Нeat conductivity of wood, страница 7

Many storage places are necessary if the timber is not to be immediately processed in the sawmill.

Revision grammar exercises.

Ex.1. Find the predicates and analyse them. Translate the sentences into Russian: 1. Wood is dried to the required moisture content in specially constructed kilns. 2. The old traditional methods of producing lumber are still being used in many countries. 3. Special mechanical devices have been designed by the Russian engineers for floating lumber. 4. Wood under water will not decay because the air supply necessary for the life and activity of fungi is lacking. 5. Animal glues can give strong joints in the dry state and their durability has been proved over years. 6. The drying rate of lumber is affected by the way the boards are stacked. 7. Experience of many decades has shown the advantages and disadvantages of animal and casein glues. 8. The most common method of seasoning wood is to place timber in the open air in piles. 9. The new technology of producing lumber has been worked out and introduced in Russia. 10. In Scandinavia, modern progressive kilns are being used extensively for drying softwoods. 11. The synthetic resins have tremendously extended the field in which plywood and other laminated products can be used.

Ex.2. Ing -forms. State the functions and translate the sentences:

1. Being placed in a dry room wood loses water from the cell cavities and from the cell walls and shrinks. 2. Sorting on the base of species increases the efficiency of the drying operation because species differ in their moisture content. 3. Having completed the cycle of its development the cell dies. 4. Cold coatings are liquid at ordinary temperatures and can be applied without being heated. 5. The main task of wood drying is the uniform reduction in the moisture content of lumber being dried. 6. The process of removing moisture from wood by evaporation is called drying. 7. Conditions being suitable for wood - destroying fungi, the service life of timber   is   very   short.                     8. Sorting   by   length and   width   simplifies   piling. 9. High

temperature destroys fungi existing in the wood. 10. Different fungi spoil the appearance of wood without affecting strength properties. 11. Having been kiln - dried, boards are light in weight and resistant to decay.

Ex.3. State the function of the ing -forms and translate the sentences:

1. Lumber being plain - sawn is cheaper and has less waste. 2. There are two basic methods of sawing logs into lumber: plain sawing and quarter sawing. 3. Thorough seasoning is advisable before applying preservatives. 4. Numerous experiments having been made, the scientists came to the conclusion that dry wood is absolutely resistant to an electric current. 5. Being placed in a humid atmosphere wood absorbs water and swells. 6. There are hundreds of species of trees possessing different properties. 7. Dry rot develops in houses because of the timber used being insufficiently seasoned. 8. After cooling the particle boards are cut according to standard sizes. 9. The most effective and economical means of preventing fungi infection is to keep the wood dry. 10. Lumber thickness is directly related to drying rate; the thicker the lumber, the longer is the time of drying.

Ex.4. State the function of the infinitives and translate the   sentences.

1. To dry wood is to increase its strength. 2. Round timber is seasoned to make it stronger, lighter, more resistant to fungus attack. 3. If you want to increase the speed of seasoning wood you will have to place timber in specially constructed kilns. 4. The main aim of wood drying is to increase its strength and prolong its service life. 5. The temperatures reached in kiln drying of lumber are sufficient to kill all types of fungi. 6. Wood to be treated with preservatives must be dried beforehand. 7. In most cases the spread of fungi is found to be dependent only on the presence of moisture in wood. 8. Paints are known to serve two main purposes -protection and decoration. 9. The main advantage of the melamine formaldehyde adhesives is considered to be their high moisture resistance and durability. 10. We know paints to protect wood from moisture, insect and fungus attack. 11. Heat conductivity of wood was found to be relatively low.

Ex.5. State the type of conditional sentences and translate them:

1. Seasoning greatly increases strength and hardness provided the wood is not injured by checking. 2. The trees would be attacked by many insects unless they were protected by bark. 3. Had the conditions been unfavourable for wood - destroying fungi, the wood wouldn't have decayed. 4. If a dry wood is placed in a humid atmosphere it absorbs water and swells. 5. If we fixed a piece of wood so as it could vibrate freely, it would emit a sound when struck. 6. Wood will serve for a long time provided it is kept dry or treated with preservatives. 7. But for the preservatives the appearance of wood would be spoiled by different fungi. 8. If the temperature in the kiln had not been so high, the boards wouldn't have split. 9. If wood were used without preliminary drying, shrinkage would occur. 10. The logs wouldn't have been attacked by fungi and insects if they had been taken from the woods and sawed into lumber at once. 11. If the lumber were dried carefully it wouldn't check and split.

Ex.6. Analyse the sentences with should and would and translate the sentences into Russian: 1. Every engineer should known the principal causes of deterioration of wood in service. 2. It is necessary that the circulating air should be humidified artificially in order to maintain the rate of evaporation at a definite level. 3. Wood in the foundation of the stack should be treated with creosote or other wood preservatives. 4. Without adhesives plywood, particle - boards, furniture and thousands of other wood products would not be possible. 5. It should be remembered that natural wood resources of the world are not inexhaustible. 6. It is important that the air circulation should be uniform over the lumber pile. 7. A kiln should be provided with means of controlling temperature and humidity of the circulating air. 8. It should be noted that acoustic properties of wood are of great importance in musical instruments. 9. The newspaper reported that the sawmill would be reconstructed at the end of this year.