Tobacco (Nicotiana tabacum L.) belongs to the group of plants that produce agricultural raw material. Besides leaves, which are used to satisfy the passion for smoking, tobacco can be used for producing oil and biodiesel, because it contains 30-40% of vegetable oil. Because of its content of citric acid, tobacco can be used for production of dyes and varnishes. Seed cake contains high percentage of proteins (35-44%) and can be used as livestock feed. Because of the high contents of lignin (40-45%) and cellulose (28-40%), tobacco stems can be used for production of energy briquettes, which makes tobacco obtain a new usability value. The aim of the experimental researches presented in this paper is to define the possibilities for production of briquettes from tobacco stems and wood raw material and to evaluate the impact of this kind of raw material on briquettes properties. For this purpose five models were made: O-control model: 100% wood raw material (BW); model T-I - 25% tobacco stems (TS) : 75% BW; model T-II - 50% TS : 50% BW; model T-III - 75% TS : 25% BW and model T-IV - 100% TS. The results of the research show that density of the briquettes is within the limits of 526.61 kg/m3 for model T-IV, to 782.73 kg/m3 for control model-O. The ash content is a little lower than the standard values and it ranges from 0.32% for O-control model, to 2.17% for model T-IV. The sulphur content is much below permissible content (0.08%), and it ranges from 0.003 to 0.008%. These briquettes, according to the low calorific value are classified in II and I class. In the smoke of the burned briquettes, minimal quantity (0.005%) of nicotine is identified

The aim of the research presented in this paper is to study the plywood tensile strength through a change of the position of layers in the panel structure around the central axis, without changing the number and thickness of veneers. So far, it has been known that the veneer layout in plywood structure has a signifi cant impact on plywood bending properties. Besides these mechanical properties, the tensile strength of plywood is also a property that can defi ne the use of plywood as a structural or non-structural panel. For studying the impact of veneer layout on plywpood tensile strength, experimental models of nine-layer plywood were made. The models were made from peeled beech veneer with the thickness of 1.2, 1.5, 2.2 and 3.2 mm. The modelling was performed on the basis of changing the position of veneer, 3.2 mm thick, around the central axis. Pure water-soluble phenol-formaldehyde resin was used as plywood binder. The tensile strength of plywood panels was tested in fi ve directions: parallel and perpendicular to the face grain, as well as at the angle of 22.5°, 45° and 67.5° to the face grain of the plywood panel. On the basis of the obtained data for tensile strength in different directions of plywood panel, the coeffi cient of equality of tensile strength of plywood models was calculated (K et). The coeffi cient of mass quality (K mq) was calculated, too. The research results showed that different veneer layouts in plywood structure have a signifi cant impact on plyood tensile strength. All tested plywood models meet the defi ned values of tensile strength in accordance with the requirements of the national (МКС) standard for structural plywood for use in construction. Different layouts of veneer sheets in panel structure give opportunities for production of panels with different strength characteristics.

BACKGROUND: The paper analyzes the properties of medium density fiberboards (MDF) intended for furniture production and interior application. Because MDF panels are one of the mostly used wood-based panels in furniture production sector in the Republic of Macedonia it is important to know and understand their basic physical and mechanical properties. AIM: For better understanding of MDF panels and their proper end use by the furniture constructors and designers, physical and mechanical properties of MDF panels present in the market are tested.MATERIALS AND METHODS: Commercially produced MDF panels taken from one company from wood-based panel market were tested. Evaluation of the quality of the panels was made on the basis of the obtained results for the physical and mechanical properties of the panels. Properties of MDF were tested according to the national MKS standards and European norms.RESULTS: Tested MDF panels present on our market are characterized by good physical and mechanical properties that meet the requirements of the standards for MDF for use in dry conditions including furniture production and interior applications.CONCLUSIONS: It is recommended to avoid application of these MDF panels in high humidity conditions for a longer exploitation period. For this kind of applications, such as bathroom areas, the furniture constructors and interior designers should consider use of MDF.H type of panel for application in high humidity conditions, which will provide good dimensional stability of the products during whole exploitation period