Лесотехнически Университет

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In the present study, an in-depth literature analysis was made regarding the theoretical problems of signs and sign-information systems as means of visual communication, about the essence of graphic design and its possibilities for creating a sign-information system as a means of communication in the "man-machine" system. , of the means of presentation of information and control (SPI) and the control bodies (OU) and the ergonomic requirements (standards) on panels of machines during their design. Based on this analysis, a system of design and evaluation criteria was developed regarding:

- the arrangement (arrangement) of the elements of the sign-information system;

- graphic design – composition and color, graphic shapes and signs;

Тhe following methods were employed during the research: theoretical analysis of the problems related to the sign-information systems for visual communication as well as the ergonomic requirements and the graphic design requirements for composition, colors, use of graphic forms and signs; analysis of the variants of sign-information systems, applied on panels (control and indicating equipment), conducted through a system of criteria in order to establish the advantages and the disadvantages of their design; graphical presentation of the analysis results employing frequency tables and graphical images – bar diagrams and others.

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In the article, a rarely mentioned in publications furniture type is considered: the tripod. The functional and symbolic meaning of this ancient artefact are researched aiming at revealing its role for the emergence of other furniture types in the XVIII^th, XIX^th and XX^th C because of the Antique Vogue and the trend for commodity search. Such objects, as stands, tables, trays, tea-tables, etc., are considered. In the process of this research, the role of this ancient archetype is revealed for the creation of modern products with a folding tripod structure, e.g., portable stools, tables, stands, etc.

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An approach for computing and research of the duration of regimes for autoclave steaming of non-frozen wooden prisms at limited heat power of the steam generator in cases of dispatching interventions into the regimes in order to obtain a duration that is suitable for the subsequent cutting of the veneer from the heated plasticized wood has been suggested. Using own 2D unsteady model implemented in the approach, calculations of the change of the duration of regimes for plasticizing of beech prisms in an autoclave have been carried out. The variables used during the computer simulation were, as follows: initial wood temperature of 0 °C, wood moisture content of 0.6 kg·kg⁻¹, and cross-section dimensions of the prisms 0.4 × 0.4 m; steaming autoclave with a diameter of 2. 4 m, length of 9.0 m, and loading level of 50% for the cases of lowering by the dispatcher the maximal temperature of the basic steaming regime from 130 ^oC to 120, 110, and 100 ^oC in the 3^rd, 5^th, and 7^th hour of this regime.

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The paper presents the differences in the color of native beech wood between the false heardwood and sapwood in the color space CIE L*a*b*. The visual evaluation of the differences in the color of beech wood between the false heardwood and sapwood clearly shows that the color of the false heardwood of beech wood has a reddish-brown color with values on the coordinates L* = 67.5, a* = 12.7, b* = 20.3 compared to sappwood, the color of which is a light white-gray color with a yellowish tinge with values on the coordinates L* = 77.1, a* = 9.5, b* = 18.4. The degree of color difference at the individual coordinates of the CIE L*a*b* beech wood color space between the false heardwood and sapwood indicates the fact that while the brightness of the false heardwood relative to the sapwood is ∆L* = -9.6 smaller, the red values ∆a* = +3.2 and yellow ∆b* = +1.9 in color are higher in the false heardwood in penetration with sapwood beech wood. A comparison of the values of the standard uncertainty of the measurement of the color of the false headrwood with the values of the relative standard uncertainty of the sapwood shows that the variability of the color shades of the brown-red color of the false heardwood is greater than the variability of the sapwood beech wood.

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Production of Medium Density Fibreboards (MDF) is one of the growing woodworking industries. It has been found that a quarter of the produced MDFs have a life cycle of up to five years, and by ten years, this amount has increased to fifty percent. There is no established industrial practice for recycling that type of waste. That, together with the fact that some countries have banned the dumping of these panels in landfills, poses significant challenges.

There are currently two main research directions on MDF recycling, namely with and without pre-treatment. In both cases, with an increase in the content of recycled fibres, a deterioration in the properties of the panels is observed. Still, the share of cut fibres and formaldehyde emissions from the boards are reduced during the preliminary treatment, mainly by hydrolysis.

In the present manuscript, a review and analysis of MDF recycling methods are performed. On that base, conclusions and recommendations are derived.

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Increasing deforestation worldwide, on the one hand, and the increased production of wood-based panels, on the other hand, lead to the need for alternative lignocellulosic raw materials. In this context, it should be said that significant amounts of lignocellulosic biomass remain annually from agricultural production, and unfortunately, that biomass is generally burned. However, individual types of lignocellulosic non-wood raw materials can hardly cover the needs of wood-based panel manufacturers, which necessitates their combination.

For the aim of the study, particleboards with a core layer of vine and hemp particles were produced. The contents of vine and hemp particles varied from 0 to 100% in steps 20%. A control panel composed only of wooden raw material was also fabricated, and the face layers of the panels were from hardwood particles.

As a result of the study, it was found that the variation in the composition of the core layer does not affect the waterproof properties of the panels. In contrast, with the increased content of hemp particles, the mechanical properties of particleboards improved significantly.

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The construction of wood can be represented by both quantitative and qualitative characteristics. Each anatomical element has quantitative indicators. These are the size of the cell gap (lumen), the thickness of the cell wall, the diameter and the length of the cell. The arrangement of these cells relative to each other is very characteristic of each species and varies relatively slightly. It is a qualitative characteristic that can also be represented by quantitative methods. Although the structure of wood varies under the influence of environmental conditions and location in the stem, the most characteristic structures remain relatively constant.

The article considers the possibility of using a formal-analytical description of the wood structure, applying abstract measurement methods. The obtained data are identical and can be processed by different mathematical methods. The proposed abstract methods give different classifications of the wood structure. Thus, a tree species in one method falls into one group with some species, in another – with others.

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Studies on the durability of tungsten carbide (TC) grooving and rebate cutter head and assessment of the quality of its sharpening have been conducted. The linear wear of the blade and the blunting radius when processing of massive coniferous wood and chipboard were studied. Recommendations were made regarding the preliminary preparation of the cutter heads and their effective operation.