Wood as a Raw Material
Wood has always been and still remains one of the most important natural raw materials necessary to man.
Wood has a wide variety of grain pattern, colours and densities. It is easily worked with tools and machines. Unlike many materials, wood is resistant to mild chemicals and insulates against electricity and heat. Indeed, the air inside its cellular structure makes timber the best thermal insulator of all known building materials. That is why wood is widely used in construction and furniture making,
in making refrigerators and cooking utensils.
On the other hand wood can burn. It can be attacked by insects and fungi. It shrinks and swells with changes in humidity.
There are many ways of avoiding deterioration of wood. It can be impregnated with preservatives to guard against biological attack. Flame retardants can protect wood from fire. Chemicals can also be applied to avoid shrinking and swelling. Mechanical and chemical treatment of wood gives products of much higher strength than the wood itself. Fibreboards and particles boards are good examples of such products.
The amount of waste in woodworking industry is several times less than that in mining and metallurgy. Energy requirement for processing wood are also lower. It takes about 1500 kilowatts hours of electricity to produce a ton of sawn timber while the production of the same weight of aluminium requires energy 45 times as much.
Nowadays wood is still often used as a fuel. When wood is burnt we lose 90 per cent of its value. Therefore much research efforts have been made and are now being made to make this useful material accessible for other purposes. New methods of processing wood are being investigated, new ways of getting valuable products out of it are being introduced.
Read the text attentively and answer the following questions:
1. Does wood still remain one of the important raw materials? Why?
2. Why is wood widely used as a building material?
3. What makes wood the best thermal insulator?
4. What are the disadvantages of wood?
5. How can deterioration of wood be avoided?
6. What can increase the strength properties of wood?
7. What other advantages of wood as a raw material are mentioned in the text?
8. Is wood still used as a fuel?
9. Is it rational to use wood as a fuel? Why?
10. What is done to make this valuable raw material accessible for other purposes?
Exercise 1. Match the English words in A with their Russian equivalents in B.
Exercise 2. Find the English equivalents to the following Russian.
разнообразие; обрабатывать; клеточная структура; мебель; гореть; грибки; насекомые; пропитывать; антисептик; защищать; огнестойкая добавка; отходы; количество; переработка; требовать; терять.
Exercise 3. Choose the words from the text which have the similar meaning.
figure; diversity; weak; heat insulator; cabinet making; durability; to permeate; to use; to prevent; quantity; needs; available.
Exercise 4. Fill in the blanks with the words from the box.
1. The history of ________ goes back to about 8 000 B.C. when people first used an ax as a woodworking ________. 2. Hardwoods have beautiful _______ and can be used to make furniture. 3. Woodworking use a wide variety of ________
to ________ wood and to bring out the beauty of the grain. 4. Wood swells if
placed in _______ atmosphere. 5. Hardwood or softwood can be used to make ________. 6. Plywood consists of an ________ number of thin _______ of wood glued together. 7. Different _________ spoil the appearance of wood without affecting ________ properties. 8. Experience of many decades has shown the ________ and _______ of wood as compared with other ________.
Exercise 1. Choose the right form of the predicate.
1. The heat from the sun ________ for thousands of years to dry timber.
2. The boards ________ before they were shipped.
3. Wooden objects thousands of years old ________ from Egyptian tombs.
4. Wafer board _______ a popular plywood substitute ideal for outdoor uses.
5. A great number of reconstituted wood materials ________ on the market of wood-based materials in the nearest future.
6. All species of wood _________ by their properties.
7. The Finnish plywood industry, famous for its high quality products ________ small diameter logs as a prime raw material resource.
8. New processing techniques for making composite materials ________ now.
9. The band saw _________ during the second half of the 19-th century.
Exercise 2. Put the verb into the required tense form.
1. Wood ________ still _________ as fuel (to use). 2. The air-conditioning system (to install) in our office now. 3. The new technology of producing lumber recently (to work out) in Scandinavian countries. 4. The trees (to shelter) the early people from wind. 5. The piece of wood (to cut and shape) by the machine-tool. 6. The air in the workshop (to purify) by 2 ventilators during the experiment yesterday. 7. Wood natural durability tests (to perform) on different species for a long time all over the world. 8. The volume of mechanically graded lumber (to increase) by nearly 25% over the past 4 years. 9. Paints (to apply) to the wood surface and do not penetrate the wood deeply. 10. Even after wood (to season) down to the desired moisture content its placement into humid atmosphere caused the new increase of moisture content and swelling.
Exercise 3. Translate into English using different tense forms.
1. Старые традиционные методы сушки древесины все еще используются во многих странах. 2. Скорость сушки пиломатериалов зависит от того как уложены (to stack) доски. 3. Различные грибки портят внешний вид древесины. 4. Бревна подверглись (to attack) воздействию грибков и насекомых, т.к. не были вывезены из леса сразу же после валки. 5. Было обнаружено, что теплопроводность древесины очень низкая (heat conductivity). 6. После того как были проведены многочисленные эксперименты, ученые установили зависимость электропроводности древесины от её плотности и вида (породы). 7. При должном управлении древесина никогда не перестанет служить человеку. 8. Древесину используют с древних времен. 9. Разрабатываются новые методы переработки древесины. 10. Большое количество материалов из реконструированной (reconstructed) древесины появилось на
1. Properties of Wood.
2. Shortcomings of wood.
3. Measure to avoid deterioration of wood.
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