Faculty of Design and Technologies of Furniture and Interior

Permanent URI for this communityhttps://repository.ukim.mk/handle/20.500.12188/7

Browse

Settings

Author: search.filters.author.Mihajlovski NikolaHas files: Yes

Search Results

Now showing 1 - 3 of 3
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Dimensional Stability and Water Absorption of Spruce Wood (Picea Abies Karst.) Impregnated and Coated with Polyurethane and Acrylic Coatings
    (Drvna Industrija, 2018)
    Mihajlovski Nikola
    ;
    Konstantin Bahchevandjiev
    Impregnating materials may affect the stabilization of wood dimensions in two ways: blocking of free water movement paths and chemical connection with hydroxyl groups of wood. The degree of modifi cation depends on the applied material, its penetration and fi xation to the wood. The paper investigates the impact of impregnation and coating with polyurethane and acrylic coatings of spruce wood (Picea abies Karst.) on absorption of water and dimensional stability of wood (anti-shrinking effi ciency) after being immersed in water for a specifi c time. Impreg nated spruce wood absorbs two times less water than untreated wood and it is dimensionally more stable than coated spruce wood. The water absorption of coated spruce wood is low, but it is not dimensionally stable.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Surface retention of polyurethane and acrylic coatings on impregnated spruce wood (Picea abies Karst.) and comparison with some wood preservatives
    (Baltic Forestry, 2022)
    Mihajlovski Nikola
    ;
    Konstantin Bahchevandjiev
    The natural spruce wood has low resistance against biological degradation and weather effects, so further protection is required, up to meeting the durability requirements for wood used in exterior classes. According to the wood preservatives standards, coatings as water repellents belong to the group OS (organic solvent) preservatives. The coatings have a water repellent function, and they are not toxic, so these advantages make them usable like impregnation material. The objective of this work is impregnation of the spruce wood (Picea abies Karst.) using the “Double vacuum process” with coating material based on polyurethane and acrylic isocyanate resins and determinate the coatings quantity in wood. The impregnation efficiency is expressed through the retention. The coatings retention is compared with the minimal standard prescribed retention of the preservatives, most frequently used, namely creosote, copper chrome arsenate (CCA) and waterborne copper-rich systems like copper azole (CBA-A, Thanalite E), to show the efficiency of the applied double vacuum process. The coating retention is not significantly different from the minimum prescribed retention of creosote and amounts 118–149 kg/m3 or 32 to 38 times higher than the recommended retention of CCA or CBA-A for wood protection in the exterior use. The polyurethane and acrylic wood coatings can be successfully applied for wood impregnation purposes.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    A review of some factors affecting the accuracy of measuring the geometric characteristics of mortise and tenon joints
    (Faculty of forest industry – University of forestry – Sofia, 2024-10-07)
    Mihajlovski Nikola
    ;
    Gruevski Gjorgi
    The geometric characteristics of mortise and tenon joints represent their ideal shape as well as the permitted deviations from that shape. Measurement accuracy as part of production metrology is of crucial importance for maintaining tolerances and fits as well as quality control in production. The closeness of the measurement results to the actual true value of the measurand depends on many factors. Some factors that affect the accuracy of a measurement are caused by the measuring equipment, the environment in which the measurement is performed, the operator who performs the measurement, the method and procedure of the measurement and the properties of the material. This review paper presents an investigation of the factors and their affect on the accuracy of measurement of mortise and tenon joints while maintaining manufacturing tolerances. The purpose of this investigation is to consider the possibility of their minimization to obtain a more accurate measurement. According to the theoretical analysis, the group of factors that express the heterogeneity and hygroscopicity of wood as a material have a great effect on the accuracy of the measurement.