Nacevski, Mitko
Preferred name
Nacevski, Mitko
Official Name
Nacevski, Mitko
Main Affiliation
Email
nacevski@fdtme.ukim.edu.mk
3 results
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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, Dimensional stability of multiplex plywood with mainly unidirectional grain orientation(SS. Cyril and Methodius University in Skopje, Faculty of design and technologies of furniture and interior-Skopje, 2021); ; Multilayer plywood made from wood veneers with mainly unidirectional grain orientation known as multiplex panels represent a significant group of modern wood-based panels. Application of these panels in modern construction and in other application areas necessitates achieving higher physical and mechanical characteristics of these materials, their consistency during prolonged water impact, humidity, heat, as well as their dimensional stability. The aim of the research presented in this paper is to study the dimensional stability of experimental multiplex plywood reinforced with cotton based prepreg. The cotton prepreg was made form cotton fabric pre-impregnated with alcohol-soluble phenol-formaldehyde resin. The experimental multiplex plywood was made of eleven layers of peeled beech veneers with thickness of 1,85 mm. Alcohol-soluble phenol-formaldehyde resin was used as plywood binder. The orientation of the veneers in the plywood structure is parallel to the longitudinal axis of the panel, with exception of the subsurface layers whose orientation is transverse to the longitudinal axis of the panel. The cotton prepreg reinforcements were inserted in each adhesive layer of plywood. To define the dimensional stability of the panels, laboratory tests on the most important physical properties were performed, as well as on bonding quality through the shear strength test. Tests of water absorption and thickness swelling were performed during prolonged water treatment. - Some of the metrics are blocked by yourconsent settings
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.