Автор: Nikolai Bardarov
- ANATOMICAL ANALYSIS OF NATURAL AND THERMALLY MODIFIED WOOD
Thermally modified wood is a unique natural material with special properties, that have been received after heat treatment of natural wood. All these properties are the result of changes in the chemical composition and structure of the wood. The paper aims to identify gaps in the structure of natural and thermally modified wood. The changes in the structure of the wood after its heat treatment were discussed.
We examined the specimens of pine, spruce, summer oak, hornbeam and birch wood. Microscopic preparations were made from the wood specimens before and after heat treatment. The three main sections of wood at different zoom were observed. There have been noticed differences in the construction of anatomical elements.
Ключови думи: thermally modified wood, pine, spruce, oak, birch, hornbeam, microscopic analysis
- VARIATION OF SOME PROPERTIES OF THE STEM RADIUS AT RESONANT WOOD
Many conditions need to be met for producing quality musical instruments. One of them is to have a consistency of structure and properties of wood. It is often difficult, especially for instruments in large dimensions. It is required to be cut large diameter trees.
The article examines variations in the density, compressive strength and flexural strength and modulus of elasticity in the radius of the stem of the spruce. A section for the manufacture of musical instruments is studied in the factory „Kremona AD” – Kazanluk. A section has stayed in dry and heated place more than 12 years. The differences in the properties of the test pieces of juvenile, central and peripheral wood have been established.
Ключови думи: resonant wood, spruce, density, compressive strength, flexural strength, modulus of elasticity
- HARDNESS OF WOOD IN SOME OAK SPECIES
The oaks are one of the most important species for our Dendroflora. This study of hardness complements the knowledge of the properties of their wood. Wood is a non-homogeneous material and its properties differ in different parts of the stem. Hardness is a property that is directly related to the construction of the wood. That is why knowledge of this property will be an important step towards more rational use of oak wood.
The work presents data on the hardness of the wood of pedunculate oak (summer) and sessile oak (winter oak). The influence of the habitat and the radius of the stem is examined. In order to compare the individual samples, the qualitative hardness coefficient was determined.
Ключови думи: wood, oak, hardness, sessile oak, pedunculate oak
- STUDY ON THE DENSITY OF OAK WOOD
The density is assumed to be a complex parameter of quality wood. On the one hand, it depends on the anatomical structure of the wood, the other largely determine all other mechanical properties and influence the processing and use of wood.
Work considered the density of oak wood, sourced from different habitats in the country and its distribution in the radius of the stem. The influence of age, the width of the annual ring, habitat and altitude.
Ключови думи: wood, oak, density, annual ring
- A STUDY OF THE DISTRIBUTION OF THE VESSELS AS A DIAGNOSTIC SIGN
The distribution of the vessels in wood is largely genetically staked for each species. Many of the features available are permanent and unique to each species. The size and density of the vessels depend to a large extent by the site conditions and the location in stem.
The article examines the distribution of the vessels of some tropical tree species. The vessels were examined in cross-section. From the next few cells are formed the figures such as loops. Attitude lap / area (V/S) of these figures is discussed.
Ключови думи: vessels, wood, distribution of the vessels, tropical tree species
- SOME FEATURES OF TIMBER QUALITY OF BETULA PENDULA ROTH. GROWING IN CARPATHIAN AGROFORESTRY
Betula pendula Roth has a wide natural area stretching from the forest to steppe zones in the Ukraine. Understanding the term „wood quality“ was focused on the industrial importance of the end-use of the wood product. Small-sized timbers of Silver birch growing in the Carpathian Agroforestry were mostly used for the chemical industry. In order to produce the valuable birch timbers was proposed a pruning at the stand height exceeding about 8-10 m with the pruning height of 5–6 m using clippers. The basic wood density varied from 419 till 631 kg∙m-3 with the mean value of 463–509 kg∙m-3. The coefficient of variation was almost equal to accepted reference value, because of many wood specimens from this birch stand were characterized by false core. The variables of wood shrinkage were ranged from 7.9 till 9.9% and from 4.6 till 6.6% in the tangential and radial sections respectively. The accuracy values of research results were under accepted reference value of 3.0%. It was discovered that the false core mostly reduced the wood properties of Silver birch. Two groups regards basic wood density less 499 kg∙m-3 with wood defects „false core“ and more 500 kg∙m-3 without any wood discoloration were recommended for the industrial timber scaling and the weight method of timber volume measuring.
Ключови думи: Silver birch, timber quality, wood density, Ukrainian Carpathians