Wood and its properties = Древесина и ее свойства. Учебное пособие

UNIT 8

COMBUSTION HEAT

1. Read the following words and state what Russian words help to guess their meaning.

Biomass, material, isolated, characteristics, facts, calculations.

2. Check up if you remember the following verbs.

To heat, to form, to accept, to spend, to burn, to isolate, to steam, to evaporate.

3. Match the following word combinations.

4. Read and translate the text into Russian.

COMBUSTION HEAT OF WOOD BIOMASS

Combustion heat of biomass is the quantity of heat released during when 1 kg of material is being burnt. The high and low combustion heats are distinguished. High combustion heat is the quantity of heat, released when 1 kg of biomass is being burnt, the resulting steam being completely condensed giving up heat the heat efficiency spent for evaporation (socalled the latent heat of evaporation). Low combustion heat is the quantity of heat released when 1 kg of biomass is being burnt without considering heat spent for evaporation, formed during fuel burning.

Combustion heat of stem wood depends only on two characteristics: ash content and humidity. Low combustion heat of stem wood is constant and equal to 18.9 MJ/kg (4510 kcal/kg).

Combustion heat of rotten wood is lower than the one of sound wood. Combustion heat of rot of destructive type is higher than of sound wood.

Only few types of research on combustion heat of different wood

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species have been performed so far, and only tentative data can be given. Low combustion heat of different wood species (kilo/kg): pine - 20 890, fir tree - 19 330, birch - 19 950, aspen - 20 780, larch - 21870. For approximate calculations combustion heat of tree crown is taken to be equal to the combustion heat of stem wood.

[From: Shmulsky R., Jones P. D. Forest Products and wood science / R. Shmulsky, P. D. Jones. – US : Willey-Blackwell, 2011. – P. 215]

5. Read the following statements and define whether they are true or false according to the text.

1.There are lots of researches about combustion heat of different wood species, and these facts are definite.

2.There is the high and low combustion heat.

3.Combustion heat of stem wood depends on many characteristics.

4.Low combustion heat of stem wood is constant and equal to 20.89 MJ/kg.

5.Combustion heat of corrosive rot is higher than that of sound wood.

6.Give the English equivalents for the words and word combinations given below and memorize them.

Горение, испарение, сжигание топлива, примерные факты, количества тепла.

7. Give the Russian equivalents for the words and word combinations given below.

Stem wood, ash content, low combustion heats, corrosive rot, heat efficiency.

8. Translate the following sentences.

1.Теплота сгорания стволовой древесины зависит только от двух характеристик.

2.Есть несколько исследований о теплоте сгорания различных видов древесины.

3.Пар образуется в процессе горения.

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9. Fill in the gaps.

1.High …………….is the quantity of heat, released when 1 kg of biomass is being burnt.

2.Low combustion heat is the quantity of heat released when 1 kg of

……………..burnt.

3.Combustion heat of…………..is lower than the one of sound wood.

4.Only few types of research on combustion heat of different

……………..have been performed so far.

10. Translate the following phrases .

Combustion heat, равный (чему-либо), destructive rot, конденсация пара, tree crown, несколько исследований, stem wood.

11. Check yourself with the following questions.

1. Can you give the definition of the term combustion?

2. Is there any difference between combustion heat of destructive rot and combustion heat of corrosive rot?

3. What does the steam forming process mean?

12. Make a summary of the text.

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UNIT 9

MINERAL SUBSTANCES

1. Read the following words and state what Russian words help to guess their meaning.

Substance, organic, mineral, sodium, calcium, magnesium, component, internal, external, wood, ashes, iron.

2. Check up if you remember the following verbs.

To consist of, to contain, to form, to pass, to burn, to depend on, to enter, to characterize

3. Match the following word combinations.

4. Read and translate the text into Russian.

MINERAL SUBSTANCES IN WOOD

The dry wood consists of approximately 99% organic compounds (low-molecular and high-molecular ones). The rest of it is inorganic mineral compounds: salts of potassium, sodium, calcium, magnesium, iron, etc. Mineral substances are present in wood sap and enter into the composition of extractive substances and components of the cytoderm.

They form ashes at wood burning. The quantity of ashes characterizes the quantity of mineral substances in wood, but it is not equal to it, because many of the inorganic compounds change into oxides or carbonates when burnt with the subsequent ignition.

Emission spectrum analysis and chemical analysis with weight, volume, photo colorimetric and other methods are used in the analysis of

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ash. Methods of ash determination are based on ash burning with subsequent ignition to constant weight. The results of the analysis are uncertain, because the quantity of ash depends on the temperature of ashing for the wood sample.

[From: Shmulsky R., Jones P. D. Forest Products and wood science / R. Shmulsky, P. D. Jones. – US : Willey-Blackwell, 2011. – P. 239]

5. Read the following statements and define whether they are true or false according to the text.

1.Dry wood consists of approximately 89% organic compounds.

2.The result of the analysis has showed the ash quantity certainly depends on the temperature of ash for the same wood sample.

3.Salts of potassium, sodium, calcium, magnesium, and iron - all of them are inorganic minerals.

4.Methods of wood ash determination are based on ash burning with subsequent ignition to constant weight.

6. Give the English equivalents for the words and word combinations given below.

Количество пепла, неорганические соединения, образец древесины, минеральные вещества, другие методы, оксиды или карбонаты.

7. Give the Russian equivalents for the words and word combinations given below.

Constant weight, chemical analysis, extractive substances, subsequent ignition, ash quantity.

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2.The methods of wood ash ………….are based on ash burning.

3.Emission spectrum analysis and chemical analysis with weight, volume,

…………….and other methods.

4.The results of the analysis are……………...

10. Translate the following phrases.

1.Высокомолекулярные соединения.

2.Горение пепла.

3.Минеральные вещества.

4.Последующее возгорание.

11. Check yourself with the following questions.

1.Which methods are used in the analysis of ash?

2.What does the term «organic compounds» mean?

12. Make a summary of the text.

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UNIT 10

SILVICULTURAL PRACTICES

1. Read the following words and state what Russian words help to guess their meaning.

Practice, cultivating, silviculture, activity, reduction, competition, nutrients, fertilizing, product definition.

2. Check up if you remember the following verbs.

To accelerate, to control, to plant, to add, to explain, to influence, to count, to yield, to lead, to measure.

3. Match the following word combinations.

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4. Read and translate the text into Russian.

SILVICULTURAL PRACTICES AND WOOD QUALITY

The practice of caring for and cultivating forest trees is known as silviculture; this activity is one of the responsibilities of the forester, whose objective is usually to accelerate growth. One method of increasing growth rate involves reduction of competition for available sunlight, nutrients, and water, which can be achieved through such practices as control of understory vegetation, thinning, or control of spacing between seedlings at the time of planting. Another approach is to add nutrients and water by fertilizing and irrigating. Growth rate of new forest stands can also be stimulated through genetic selection of seed or planting stock. Tremendous increases over natural growth rates are possible. Before examining how silvicultural practices affect wood quality, it is necessary to explain the concept of quality. Quality can be generally defined as a measure of the characteristics of wood that influence properties of products made from it. Briggs and Smith (1986) put it differently, saying that “wood quality is a measure of the aptness of wood for a given use. ” A more precise definition of quality can be elusive because characteristics important in wood to be used for one product are often different from those for another product. In one case, quality may be measured in terms of density, uniformity of growth rings, and percent of knot - free wood, whereas in another instance, properties such as proportion of latewood, cellulose yield, and the fiber to - vessel ratio may be primary quality indices. Larson (1969) provided insight into the matter of wood quality when he wrote: “ During wood formation, numerous factors both inside and outside the tree lead to variation in the type, number, size, shape, physical structure, and chemical composition of the wood elements. Wood quality is the arbitrary classification of these variations in the wood elements when they are counted, measured, weighed, analyzed, or evaluated for some specific purpose. Wood quality is therefore a concept. ” Although the concept of quality may be difficult to pinpoint, several factors influence the suitability of wood for a variety of purposes. These factors include density, uniformity of growth rings, fi be length, percent of clear bole, straightness of grain, proportion of heartwood, percentage of vessels (in hardwoods), and presence of juvenile and reaction woods.

[From: Shmulsky R., Jones P. D. Forest Products and wood science / R. Shmulsky, P. D. Jones. – US : Willey-Blackwell, 2011. – P. 253]

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5. Read the following statements and define whether they are true or false according to the text.

1.Silviculture is the practice of caring for and cultivating forest trees.

2.Caring for and cultivating forest trees is the responsibility of the government.

3.The main objective of a forester is to diminish the competition between trees.

4.The concept of quality is the primary thing to determine.

5.Nowadays there exists the precise definition of the wood quality.

6.Give the English equivalents for the words and word combinations given below and memorize them.

Обнаружить, рост, конкуренция, способность дерева подходить под, качество, практика ухода, равномерность колец, контроль пространства, развиваться в полную силу, генетический отбор.

7. Give the Russian equivalents for the words and word combinations given below.

Concept, growth rate, to pinpoint, genetic selection, practice of caring, cultivating, to control, nutrients, fertilizing, to yield.

8. Fill in the gaps.

1.One of the responsibilities of the forester is usually to……………….

2.This can be achieved through such practices as control of

………….vegetation, thinning, or control of spacing between seedlings at the time of planting.

3.Growth rate of new forest stands can also be stimulated through

…………….of seed or planting stock.

4.Before examining how ………….practices affect wood quality, it is necessary to explain the concept of quality.

5.Quality can be generally ………..as a measure of the characteristics.

6.Briggs and Smith put it differently, saying that “wood quality is a

…………………of wood for a given use”.

7.Wood quality is therefore a……………..

8.Characteristics which are important in wood to be used for

……………..are often different from those for another product.

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9.During wood formation, numerous factors both inside and outside the tree lead to………….., number, size, shape, physical structure, and chemical composition of the wood elements.

10.A more precise definition of quality can be………...

9. Translate the following sentences from Russian into English.

1.Практика ухода за деревьями хорошо известна.

2.Основной целью является увеличение темпов роста древесины.

3.Один из методов увеличения темпов роста состоит в сокращении конкуренции за основные питательные вещества.

4.Другой подход заключается в добавлении питательных веществ и воды путем ирригации.

5.Ключевым фактором является разъяснение качества древесины.

6.Характеристики одного вида продукта могут значительно отличаться от другого.

7.Плотность и равномерность колец древесины очень важная характеристика с одной стороны.

8.Качество древесины не является основной характеристикой классификации.

9.Концепция качества сложно поддается определению.

10.Translate the following phrases.

Контроль пространства, to pinpoint, подходить под, growth, развиваться в полную силу, practice of caring, генетический отбор, to control, обнаружить, nutrients, равномерность колец.

11. Check yourself with the following questions.

1. Can you give a definition of the “silviculture” term?

2. What is the main responsibility of a forester?

3. How can you explain the concept of quality?

4. What is the author’s opinion about the concept of quality?

5. Why doesn’t the author stand for a more precise definition of quality?

12. Make a summary of the text.

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