Stamenkoska, Ana-marija
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Stamenkoska, Ana-marija
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Stamenkoska, Ana-marija
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Item type:Publication, Determination of the heat energy for hydrothermal treatment of ashwood (Fraxinus excelsior) by log soaking(Faculty of Design and Technologies of Furniture and Interior - Skopje, 2023-09); The treatment of logs by soaking is a complex technological and thermal procedure, in which logs and prisms are used as raw material for the production of peeled and sliced veneers. Such treatment of logs is carried out in pools or pits constructed in the ground. By log soaking two significant changes to the wood are achieved, its coloring and the inevitable plastification of the wood fibers. During this procedure, the time required for air drying is significantly reduced. The soaking medium is fresh water or previously used water at an elevated temperature. This soaking treatment is particularly suitable for logs for the production of peeled and sliced veneer, from which resin must be removed. Soaking is also used when treating wood species that are sensitive to steaming. This paper provides an analysis of the thermal energy required for hydrothermal treatment by log soaking of ashwood (Fraxinus excelsior). The logs were intended for the production of peeled veneer. The log treatment was done in a reinforced concrete pool built in the ground. The total amount of heat for log soaking (Q) consists of effective heat (Qpv) and heat loss (Qzv). The procedure was conducted by the strong treatment mode, with a temperature interval in the range of 70 to 90 °C. The treated logs had a minimum mean diameter of 35,0 cm and a minimum length of 1,8 m. Log soaking was used as a method for defrosting of the logs, due to their low initial temperature, which was– 15 °C. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Comparison of log taper in different wood species(Department of Wood Technology, Faculty of Forestry and Wood Technology, University of Zagreb, Croatia, 2023-12); ; The rational yield of the sawlogs is one of the key factor for the prosperity of the sawmill capacity. One of the factors that significantly influence the maximum quantitative yield of sawlogs is the diameter taper. The diameter taper is an inevitable sawlogs occurrence and it is determined by the geometry of the logs. The diameter taper is defined as the difference between the diameters of the two ends of the log, alongside its length. Great differences between these two diameters adversely affect the percentage of maximum quantitative yield. This parametar plays a fundamental role in the classification of logs into quality classes. The aim of the paper is to compare the diameter taper in different wood species. Wood species of interest are: beech (Fagus sylvatica L.), pine (Pinus sylvestris, Pinus nigra), oak (Quercus sessiliflora), and fir/spruce (Abies alba/Picea excelsa). Log length is of important influence in the value of log taper. Therefore, the analysis for the different wood species will also present different groups of lengths, in order to determine the different values for the log taper. The selection of wood species is for the purpose of comparison of the taper values in deciduous and coniferous wood species. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Technical analysis of a metal chamber for direct steaming of beech lumber (Fagus sylvatica L.)(Faculty of Design and Technologies of Furniture and Interior - Skopje, 2023-12); ; The aim of this paper is the technical analysis of a metal chamber for direct steaming of beech (Fagus sylvatica L.)-edged lumber with a thickness of 50.0 mm. The paper presents the basic parameters of the chamber and calculates the dimensions of the metal chamber and its capacity. The dimensions of the chamber with sawn lumber, the number of chambers, and the volume of the single lumber stack have been analyzed. The steaming of the wood is an important and complex operation during the processing of sawlogs into sawn lumber. Steaming, in addition to being a technological procedure, is also a thermal procedure. The steaming of the sawn lumber is carried out in the presence of water vapor in steaming chambers according to the following two methods: direct steaming of the sawn lumber and indirect steaming of the sawn lumber. In the method of direct steaming of lumber, the steaming medium is saturated water vapor. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Impact of feed rate on roughness of the cut surface, during cutting dry beech and spruce wood with a circular saw(Ss. Cyril and Methodius University, Skopje, North Macedonia, Faculty of Design and Technologies of Furniture and Interior, Skopje, 2025-11); ; ; The precision of wood processing and the quality of the machined surface are critical factors in achieving the desired processing outcomes. These factors are influenced by a variety of parameters, among which the feed rate during mechanical processing plays a significant role in determining the surface roughness of the cut. Surface roughness, often caused by tool marks, affects subsequent hydrothermal treatments and other mechanical processes, ultimately reducing the efficiency of wood usage when it is too high. For this purpose, in this paper, the dependence of the feed rate on the roughness of beech and spruce wood during the cutting of dry wood with a circular saw is investigated, with the intention of determining the optimal cutting conditions for obtaining lower values of the roughness. In this research, three different feed rates were applied (U1 = 12 m·min-1 , U2 = 16 m·min-1 and U3 = 20 m·min-1 ) for a constant cutting height of 15 mm in dry beech and spruce wood with moisture content W = 10 ± 1%. The measurements were made with a circular saw with a diameter of cutting tool D = 250 mm, a number of teeth Z = 40 and a width of the cut b = 3.2 mm. The number of rounds was n = 5500 min-1 . Roughness measurements were taken with a digital comparator, according to the Rmax criterion. The obtained results showed a pronounced significance and a directly proportional dependence of the roughness of the cut surface on the feed rate - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Solar drying of wood(Faculty of Design and Technologies of Furniture and Interior - Skopje, 2023-12); ; Solar energy represents an alternative source of energy supply, which has also found its application in wood processing technology. In particular, solar energy finds great application in the field of wood drying. Solar energy is defined as the emitted light and heat produced by the sun, which is harnessed with the help of developing technologies such as solar collectors, photovoltaic cells, solar and thermal collectors, various types of solar architecture, plantations and reactors that use molten salts, and technologies of artificial photosynthesis. The purpose of this paper is to give a brief overview of solar drying technology. A special review is given to solar drying methods. The method of work does not cause experimental research in practice but represents a collection of used literature and individual research. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Processing sawlogs into parquet blanks(FACULTY OF FOREST INDUSTRY – UNIVERSITY OF FORESTRY – SOFIA, 2024-12); ; ; ; The term parquet refers to a floor covering made of solid wood, consisting of interconnected slats in a horizontal plane. A parquet strip is the principal constructional element of the parquet. This wooden strip is obtained as a result of processing the flooring blank. In the sawmill processing of the sawlogs, the flooring blanks are sawn from the sawlogs, mostly in the radial and tangential direction. For such a purpose, sawlogs from domestic species and foreign species are used. Most dominant in this manner are the hardwood species, although softwood species can be used too. Among the domestic species, the most are beech, oak, acacia, elm, ash, and from the softwood species pine and larch. The paper focuses on the maximum quantitative yield of beech and oak sawlogs intended for processing into parquet blanks. The sawing was conducted on a bandsaw. The blanks were with a thickness of 25,0 mm. The sawlogs belonged to the I, II, and III quality classes. A total of 12 sawlogs were processed, 6 from beech (Fagus sylvatica L.) and 6 from oak (Quercus robur). All sawlogs were with a constant length of 3,0 m. The mean diameter for beech and oak sawlogs was in the range of 34,0 to 36,0 cm. The average value for the quantitative yield for beech sawlogs from I, II, and III quality classes was 37,90%. For the oak sawlogs from I, II, and III quality classes the average value of the quantitative yield was 39,40%. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Analysis of heat and steam consumption during artificial convective drying of oak sawn timber of different thickness(Faculty of Design and Technologies of Furniture and Interior - Skopje, 2023-09); ; ; ; In the paper, the consumption of heat and steam of oak sawn timber with a thickness of 25,0 and 50,0 (mm) are analyzed under conditions of classic convective drying. The drying mode is compiled on the basis of data on the temperature of the drying agent (air), the relative humidity of the air and the speed of air movement in accordance with the current value of moisture in the wood. The heat consumption is analyzed in all stages of the drying cycle such as heating the wood, active drying of the wood, equalization of the average moisture in the wood and conditioning, i.e. equalization of the moisture in the cross-section within ± 2.0 (%). The moisture content of sawn timber at the beginning of drying is about 55,0 (%) and at the end of drying is 10,0 (%). The sawn timber are intended for the production of solid wood panels. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Analysis of heat consumption during convective wood drying of beech sawn timber of different thickness(Faculty of Design and Technologies of Furniture and Interior - Skopje, 2025-09); ; In the paper, the heat consumption of beech sawn timber with a thickness of 50,0 and 70,0 (mm) are analyzed under conditions of classic convective drying. The drying mode is compiled on the basis of data on the temperature of the drying agent (air), the relative humidity of the air and the speed of air movement in accordance with the current value of moisture in the wood. The heat consumption is analyzed in all stages of the drying cycle such as heating the wood, active drying of the wood and conditioning, i.e. equalization of the moisture in the cross-section within ± 2.0 (%). The moisture content of sawn timber at the beginning of drying is about 45,0 (%) and at the end of drying is 8,0 (%). - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Comparative analysis of yield distribution in first and second-class quality fir and spruce sawlogs (Abies alba Mill./Picea abies L.): A case study from North Macedonia(Faculty of Design and Technologies of Furniture and Interior - Skopje, 2024-12)The efficient utilisation of sawlogs represents a crucial determinant for the operational success of sawmill capacities. Sawlogs serve as the primary raw material in sawmill operations, and their rational use is influenced by several production-related factors. Key determinants impacting sawlog utilisation include wood species, log quality classification, technological capacity of sawmills, and workforce proficiency, among others. Of particular importance to sawlog processing methods are wood species and quality classification. A principal indicator of sawmill performance lies in the quantitative yield of raw material, defined by the volume of lumber produced from log processing. The economic viability of sawmills is grounded in this quantitative utilisation, with wood species and quality classification exerting the most substantial influence. This paper presents findings from a comparative analysis conducted at a sawmill facility in Berovo, Republic of North Macedonia. It examines the yield from fir/spruce (Abies alba Mill./Picea abies L.) sawlogs of both first- and second-quality classes. The analysed logs maintain a consistent length of 4.0 meters. The average diameter for first-class logs ranges from 27.0 to 57.0 cm, while for second-class logs, it spans 38.0 to 62.0 cm. The mean yield rate for first-class logs is 68.93%, and for second-class logs, it is 61.55%. A comparative analysis is provided for the coarse and fine waste generated from log processing for both quality classes. Sawing was conducted using a horizontal band saw, and the resulting lumber is designated for construction and structural purposes. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Analysis of the influence of the length of beech sawlogs (Fagus sylvatica L.) on the maximum quantity exploitation(Faculty of Design and Technologies of Furniture and Interior - Skopje, 2021-09); ;