- •Часть II
- •Д.Ю. Коновалов, ст. Преп. Каф. Безоп. Технол. Процессов и производств агту, кандидат с.-х. Наук
- •Ббк 81.2 англ – 92
- •Unit 1 Environmental Aspects of Timber
- •Answer the questions:
- •Read the text and try to understand it.
- •Vocabulary
- •Read one more text on the problem and do the tasks.
- •Translate from Russian into English using the vocabulary of the Unit.
- •V. Speak about:
- •Heat Conductivity of Wood
- •Answer the questions:
- •What properties of wood do you know?
- •Read the text and try to understand it.
- •Vocabulary
- •Read one more text on the problem and do the tasks. Heat Conductivity
- •IV. Translate from Russian into English using the vocabulary of the Unit.
- •V. Speak about.
- •Species of Trees and Their Application
- •Answer the questions:
- •Read the text and try to understand it.
- •Vocabulary
- •2. The timber used was insufficiently seasoned.
- •Read one more text on the problem and do the tasks. Classification of Species
- •Translate from Russian into English using the vocabulary of the Unit.
- •V. Speak about:
- •Fireproofing
- •Answer the questions:
- •Read the text and try to understand it.
- •Vocabulary
- •Insert the words from “a” into the sentences given below.
- •Indicate the word combinations that:
- •Read one more text on the problem and do the tasks.
- •Inflammation of Wood
- •Translate from Russian into English using the vocabulary of the Unit.
- •V. Speak about:
- •Infinitive: Forms and Functions
- •Storage of Logs in Sawmill Yards
- •I. Answer the questions:
- •II. Read the text and try to understand it.
- •Vocabulary
- •Read one more text on the problem and do the tasks.
- •Translate from Russian into English using the vocabulary of the Unit.
- •Speak about:
- •Infinitive Constructions: Complex Subject Complex Object
- •Timber Drying Methods
- •Answer the questions:
- •Read the text and try to understand it.
- •Vocabulary
- •Read one more text on the problem and do the tasks. Why Dry Lumber?
- •Translate from Russian into English using the vocabulary of the Unit.
- •V. Speak about:
- •Infinitive. Revision
- •I. Answer the questions:
- •Read the text and try to understand it.
- •Vocabulary
- •Insert the words from list “a” into the sentences given below.
- •Specialists suppose that one hectare of coniferous forests sucks annually 30 tons of dust.
- •Everybody knows that wood is a renewable raw material.
- •Read one more text on the problem and do the tasks. The Requirements to Hardwood Lumber Drying
- •IV. Translate from Russian into English using the vocabulary of the Unit.
- •V. Speak about:
- •Revision
- •Wood-based panels – Plywood
- •I. Answer the questions:
- •II. Read the text and try to understand it.
- •Vocabulary
- •Insert the words from list “a” into the sentences given below.
- •III. Read one more text on the problem and do the tasks. Laminated Veneer Lumber and Other Structural Sections
- •Translate from Russian into English using the vocabulary of the Unit.
- •V. Speak about:
- •Unit 9 Revision
- •Wood-based panels: Fibreboard, Particle board
- •I. Answer the questions.
- •II. Read the text and try to understand it.
- •Vocabulary
- •Insert the words from list “a” into the sentences given below.
- •Read one more text on the problem and do the tasks. Wood-Based Panels. Oriented Strand Board
- •IV. Translate from Russian into English using the vocabulary of the Unit.
- •V. Speak about:
- •Unit 10 Revision
- •Sawmill Process
- •Answer the questions.
- •Vocabulary
- •Insert the words from list “a” into the sentences given below.
- •Read one more text on the problem and do the tasks. Sawing Machinery
- •Translate from Russian into English using the vocabulary of the Unit.
- •V. Speak about:
- •Contents
- •The List of Literature Used
- •Vocabulary
IV. Translate from Russian into English using the vocabulary of the Unit.
Воздушная сушка – один из старейших способов сушки древесины.
Метод штабелевки пиломатериалов зависит от размеров высушиваемых материалов.
Главная цель штабелевки - обеспечить свободный проход воздуха.
Выбор метода сушки зависит от породы древесины и климата.
Фундамент под штабелем должен обеспечивать свободное движение воздуха.
Эффективность сушки на бирже зависит от того насколько хорошо выровнена и дренирована поверхность грунта.
Лиственные породы, будучи очень плотными, требуют более длительных сроков сушки для достижения желаемого влагосодержания.
Сушка повышает ценность древесины.
Должная сушка сводит до минимума качественные потери пиломатериалов.
Если влагосодержание составляет менее 20%, то древесина не будет подвержена поражению грибками и насекомыми.
Вес высушенной древесины значительно снижается.
Потребители требуют исключительного качества высушенных пиломатериалов.
Потребителям известны факторы, влияющие на стоимость пиломатериалов.
Специалисты мебельной промышленности знают, что увеличение выхода на 1% благодаря качественной сушке, может снизить стоимость деталей более чем на 40 долларов на тысячу досковых футов.
V. Speak about:
1. The requirements to air-drying of wood.
Unit 8
Revision
Grammar:
Wood-based panels – Plywood
I. Answer the questions:
1. What wood-based panels do you know?
2. What is plywood?
3. Where is plywood used?
II. Read the text and try to understand it.
Wood in thin layers, known as plies or veneers, has been used since ancient times for example by Egyptians and Romans to finish wooden surfaces. Since the beginning of the 20th century, plywood has been industrially produced. Plywood as a building material consists of an odd number of layers (at least three) which are bonded using various types of adhesives. The suitability of plywood for the aircraft industry initiated intensive research into veneer bonding and the structural properties of plywood. Initially only natural adhesives were available but today plywood as a constructional material is produced using synthetic adhesives. Plies can be manufactured by rotary peeling, slicing or sawing. Plies for the structural plywoods used in building components are produced by the rotary peeling of steamed logs. This procedure resembles the unwinding of the log to obtain a wooden ribbon of about 2 mm to 4 mm thickness. The next step is to cut the ribbon into sheets. After kiln drying and gluing, the veneers are laid up with an angle of 90º between the grain direction of adjacent layers and bonded under pressure. Adjacent veneers provide stability in the panel by reducing the possibility of perpendicular to the grain movements due to swelling and shrinkage. The edge of the panel is protected in all directions since at least one veneer will have the grain running parallel to the panel edge. Plywood is structurally suited for use as a panel material in various components, for example as the web or flange of beams, in diaphragms, as wall panels or as gussets in spaced columns and trusses.
One of the most important physical properties of wood based materials is the density. Depending on the percentage of adhesive and the compression of the bonding, the density of plywood is generally higher than the density of the wood from which it is made. As with solid timber, the elastic properties and strength of plywood are correlated with density.
Like solid wood, the veneers are hygroscopic, and therefore the moisture content of plywood depends on the climatic conditions of the surrounding air. The moisture content of plywood is less than of solid timber due to glue lines. Changes in plywood moisture content cause changes in the geometrical properties of plywood panels. The increase in deformation of plywood with time is due to combined effect of creep and moisture. Plywood panels are slightly more prone to creep than solid timber due to the glue lines.
The natural durability of wood based panels depends less on the species of wood than solid timber. Additional factors which really affect the durability of plywood are:
- thickness of veneers
- composition
- properties and quality of adhesives.
Improved durability can be obtained by using selected wood species for the veneers, special lay-ups or by chemical protection.
Due to the excellent physical and mechanical properties and nice and original texture of wood the plywood is successfully used in the furniture industry, radio-engineering, construction and other branches of industry.
General understanding
Answer the questions:
Who were the first to use wood in thin layers?
When was the industrial production of plywood started?
What is plywood?
What number of piles does plywood usually consist of?
How are piles manufactured?
What use is plywood structurally suited?
What is one of the most important properties of wood?
What does the moisture content of plywood depend on?
Is moisture content less or more than that of solid timber?
What factors affect the durability of plywood?
How can improved durability be achieved?
Where is plywood successfully used?