Faculty of Design and Technologies of Furniture and Interior
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Item type:Publication, Determination of the fiber saturation point of autochthonous and allochtonous wood species(Faculty of design and technologies of furniture and interior-Skopje, 2019); ; The aim of this research is to determine the fiber saturation point of wood from Fagus moesiaca, Quercus sessilis, Quercus conferta, Robinia pseudoacacia, Pinus nigra, Pinus silvestris, Abies alba, Picea excelsa, Pseudotsuga menziesii, Cupressus arizonica, Sequoiadendron giganteum, Pinus strobus and Larix decidua, as a contribution to the utilization of wood. The material used for investigation was collected from twenty-eight methodologically selected localities. The obtained average values of fiber saturation point are based on wood density and volume shrinkage, in accordance with the standard for wood investigation. The results from investigation of fiber saturation point of wood from autochthonous species are within the limits of the up to now empirical and scientific knowledge. The obtained values for the allochthonous species that are subject of our investigation, can significantly impact on further introduction. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Variations of the hardness of Balkan beech wood (Fagus moesiaca cz.)(Faculty of design and technologies of furniture and interior-Skopje, 2019); ; The aim of this research is to determine the significance of the impact of the origin of wood trees (generative or vegetative), height of the cross-section (1,3 and 5,3 m above ground) and relative age of annual rings (distance from pith in radial direction) in which the measurements are made, on the variation of wood hardness, at near same ecological factors. For determination of wood hardness Brinell method is used, and for statistical processing of the data from the measurements, software package SPSS Statistics 21 is used. On the basis of the obtained values form the tests for normal distribution of the hardness and analysis of the homogeneity of the variance, as well as on the basis of multiple comparison for determination of statistical significant differences between average values of wood hardness from different tree trunks, cross-section and age, it is found that the trees from vegetative origin produce wood with significantly higher hardness compare to the trees form generative origin. Among the two cases, the wood hardness of section 1,3 m is significantly higher than the wood hardness of section 5,3 mm. The increment of the relative age of annual rings in trees from vegetative origin in certain interval is followed by increment in wood hardness, whereupon the wood hardness decreases, while in trees from generative origin, first in certain interval the hardness is decreased, whereupon it is increased. The obtained results of these researches, supplemented with the comparative researches of processing of standard (from generative origin) and nonstandard (from vegetative origin) timber should be taken in consideration when choosing the technological process. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Physical properties of plywood during prolonged water exposure(Faculty of design and technologies of furniture and interior-Skopje, 2019); ; Mihajlova, JulijaТhe aim of this research is to study the physical properties of experimental plywood bonded with alcohol-soluble phenol-formaldehyde resin during prolonged water exposure. On the basis of the obtained data for the changes of the physical properties of plywood after exposure to prolonged water treatment of 192 days, water resistance of experimental plywood is evaluated. Tests for the thickness swelling, volume swelling and water absorption are made after immersion in water for prolonged period in controlled laboratory conditions. The measuring of thickness, length, width and mass of plywood test specimens for determination of these properties is made after immersion in water for the period of 1 day (24 hours) to 192 days (4608 hours). Plywood model in this experiment was made from peeled beech veneers bonded with pure alcohol-soluble phenol-formaldehyde resin. The results from the research showed that the plywood model is characterized by uniform density; it is dimensionally stable during and after prolonged water exposure, without any deformations of the shape of the test specimens. The changes of the values of thickness and volume swelling, as well as the values of water absorption in the analyzed period are proportional to change of the duration of the period of water exposure. According to the obtained data from the tests of these properties the plywood model meets the requirements for load-bearing plywood for use in construction. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Research on the properties of light boards from ligno-cellulose materials and cement(Faculty of design and technologies of furniture and interior-Skopje, 2019); The aim of this research is production in laboratory conditions of light weight boards from different types of ligno-cellulosic materials and Portland cement as inorganic binder. Wood particles from recycled coniferous wood (white pine) and recycled deciduous wood species are used as ligno-cellulosic materials, as well as particles from grape vine rods, flax and hemp. Gel made from aluminum sulphate and sodium silicate solution (water glass) is used for mineralization of the particles. Boards with thickness of 50 mm and dimensions of 400×400 mm are made in laboratory conditions. Test specimens for determination of the most important physical and mechanical properties re made from the boards. Some test specimens are used for determination of the coefficients of sound absorption and thermal conductivity. The results from the research show that light-weight boards from ligno-cellulosic materials and cement with density bellow 0,630 g/cm3 can be classified as structural-insulation materials. Insulation properties and strength properties of investigated boards indicate that the latter meet the requirements for application in construction as a material for components of wall panels, permanent formwork, roof panels, partition walls etc. The obtained light-weight boards made of ligno-cellulosic materials and cement are a good option for sustainable material management, with a view to protecting, preserving and improving the quality of the environment, protecting human health, ensuring prudent, efficient and rational utilization of natural resources. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Screw withdrawal resistance of composite wood-based panels (Part II)(Faculty of design and technologies of furniture and interior-Skopje, 2019); ; Mihajlova, JulijaThe aim of the research presented in the paper is to determine the screw withdrawal resistance of composite wood-based panels intended for use in construction. For this purpose, three experimental wood composite panels were made by combining particleboards and constructive peeled veneers of beech, black pine and poplar with thickness of 1,5 and 3,2 mm. The core layer of the composite panels was made of single-layer particleboard with thickness of 16 mm which was overlaid on both sides with two-ply cross-laminated veneers. Models of composite panels were made by combining a different veneer species for particleboard overlay (beech/black pine, poplar/black pine and poplar/beech). Water-soluble phenol-formaldehyde resin was used for particle bonding and veneering. The results from the research showed that the different combination of veneer species used for particleboard overlay significantly impact the screw withdrawal resistance of composite panels. According to the obtained values of the screw withdrawal resistance, composite panels can be used in construction. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Water impact on change of physical characteristics of single-layer water–resistant particleboards(Ss. Cyril and Methodius University in Skopje, Faculty of Design and Technologies of Furniture and Interior in Skopje, 2013); The paper elaborates water impact on change of physical properties of single-layer water-resistant particleboards. The water impact is analyzed in controlled laboratory conditions through the change of density, volume, thickness swelling and water absorption in the period of 1248 hours (52 days). Experimental panels are made of beech particles. The particles are glued with phenol-formaldehyde resin. The results from the research showed that the panels are characterized by uniform density, stability in volume, without any deformation of the shape and dimensions of the test specimens. The changes of the properties in the analyzed period are proportional to the change of the treating period of the test specimens. The panels have dimensional stability and meet the requirements of the standards for non-structural use in construction. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Impact of Veneer Layouts on Plywood Tensile Strength(Faculty of Forestry, University of Zagreb, 2017); ; The aim of the research presented in this paper is to study the plywood tensile strength through a change of the position of the layers in the structure of the panel around the central axis, without changing the number and the thickness of the veneers. So far it is known that the veneer layouts in plywood structure have significant impact on plywood bending properties. Besides these mechanical properties, the tensile strength of plywood is also a property that can defines the plywood use as structural or non-structural panel. For studying the impact of veneer layouts on plywpood tensile strength, experimental models of nine-layer plywood are made. The models are made from peeled beech veneers with thickness of 1.2, 1.5, 2.2 and 3.2 mm. The modelling is made on the basis of changing the position of veneers with thickness of 3.2 mm around the central axis. Pure water-soluble phenol-formaldehyde resin is used as plywood binder. The tensile strength of the plywood panels was tested in five 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 coefficient of the equality of the tensile strength of the plywood models was calculated (Ket). The coefficient of mass quality (Kmq) was calculated too. The research results showed that the different veneer layouts in plywood structure have significant impact on plywood tensile strength. All tested plywood models meet the defined values of tensile strength in accordance with the requirements of the national (МКС) standard for structural plywood for use in construction. The different layouts of veneer sheets in panel structure gives opportunities for production of panels with different strength characteristics.