Лесотехнически Университет

Summary

Experimental studies related to the influence of some factors on the quality of the resulting lumber were carried out. The venue of the research is the manufacturing conditions in Experimental and Training Forest Ranges in Barziya. As a work station a horizontal bandsaw for logs Arsov 90 Ltd. (Bulgaria) was used. The results were analyzed and compared to some earlier obtained with other machines of this type. They show that it is not advisable feed speed to exceed 16 m.min^-1– due to the risk of unacceptable size deviations. Some recommendations for a more efficient usage of this type machines were proposed.

Summary

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.

Summary

Experimental studies during milling of solid wood were carried out. The current study was performed at the Laboratory of Woodworking Machinery, University of Forestry, Sofia. The measurements were carried out using universal milling machine FD – 3 (ZDM – Plovdiv). The correlations between fundamental factors influencing the milling process and target functions, such as cutting force and power, specific cutting work, specific power consumption have been investigated. On the basis of the analysis of the obtained results, practical recommendations have been proposed.

Summary

The popularity of design thinking in the last few years is part of a wider debate about the role of design in business, and its place in business education. The reason for the surge in interest of the ‘methodology’ of design, is because of design potential for enabling business – and cultural – transformation, through the application of design processes to other areas. Many famous brands are experimenting with ways to embed design thinking in their organizational processes, and in using it as a company-wide innovation tool.

Summary

In this paper are presented the results of an experimental study of the performance of multifunctional forestry tiller FAE 300/S, powered by a self-propelled unit PT-400, for soil preparation for poplar plantations establishment. The machine is tested in different speed regimes while mulching the shrubs, coppice and wood debris from the felling areas. The other observed operation is soil tillage up to 50 cm. The study was conducted in poplar clearings along the Danube River. The purpose is to establish the fuel consumption and the performance of the machine at different milling speed. Based on the results are constructed graphical dependencies, in order to express the relative fuel consumption and operational performance, depending on the operating speed of the machine. At the end is performed an optimization of the process of deep tillage of the soil, using the criteria for minimizing the power consumption. And based on this is defined optimal operating speeds of the examined forestry tiller.

Summary

Wood is a raw material in short supply both in Bulgaria and worldwide. In Bulgaria, vine twigs are widespread lignocellulosic waste from agricultural production.

In this study, the effect of inclusion of vine fibres in the composition of fibreboards on their properties is presented. Vine fibres were obtained by means of defibration with a defibrator laboratory mill. For the purpose of the study, fibreboards were produced under laboratory conditions with inclusion of vine fibres at a content from zero to twenty percent in increments of five percent. The main physical and mechanical properties of the boards were determined. On this basis, analysis was made and respective conclusions were drawn.

Summary

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.

Summary

The expansions of the raw material base for solid wood materials production are particularly important in terms of wood deficit and increased consumption. The aim is to use solid wood materials production like replacement wood, which doesn’t deteriorate the performance of the finished products, as well as technical and economic production parameters. The Douglas fir (Pseudotsuga menziesii) is non popular wood species for Republic of Bulgaria. The studies for our country show that this tree species well adapted in these conditions, particularly in areas with high humidity. This gives reason to believe that this tree species is perspective for the production of solid wood materials.

This report presents the results of studies about the size and quality characteristics of Douglas fir stems.

Summary

This report will present the results achieved by Engineering Design students, Bachelor Degree during semester 6. The developed methodology is implemented in the design discipline ‘Residential Interior and Furniture Design’at the University of Forestry in Sofia, Bulgaria, and it is a part of PhD thesis entitled “IMPLEMENTING THE SYSTEMATIC APPROACH IN CHILDREN ENVIRONMENT DESIGN FOR THE CONTEMPORARY DWELLING”. The methods used in the design class are observation and analysis of results, demonstrated by students.

To make the understanding of design methodology easier and clearer, specific examples are considered. Initially, a simplified (to a certain extent) provisional design scheme is analyzed and gradually progressed to a more complex design assignment.