Pub Date : 2023-12-21DOI: 10.31926/but.fwiafe.2023.16.65.3.4
I. Deaconu, M.C. Timar, B. Bedelean, M. Campean
The paper presents the experimental results concerning the amount of extractable substances and the color changes determined by the reaction of the tannins contained in wood with iron. Tests were performed comparatively with sapwood and heartwood samples of two Quercus species, namely Turkey oak (Quercus cerris L.) and sessile oak (Quercus petraea (Matt.) Liebl.). The findings show that Turkey oak sapwood has an unexpectedly high amount of extractable substances, higher than the heartwood of the same species. This result was obtained with three extraction methods (cold water, hot water, and NaOH 1% solution). The FTIR investigation of the extracts impregnated on quantitative filter paper seems to confirm these results. Visual assessment and color measurements after applying FeCl3 highlight that both oak species are prone to staining in contact with iron due to their tannin content. The values of the total color difference between the state and after the reaction with FeCl3, lower fer for Turkey oak compared to sessile oak, correlate with a lower extractive content of this wood species.
{"title":"Comparative Research Regarding the Hydrophilic Extractives Content in Turkey Oak and Sessile Oak Wood and Their Related Staining Susceptibility by Reaction with Iron","authors":"I. Deaconu, M.C. Timar, B. Bedelean, M. Campean","doi":"10.31926/but.fwiafe.2023.16.65.3.4","DOIUrl":"https://doi.org/10.31926/but.fwiafe.2023.16.65.3.4","url":null,"abstract":"The paper presents the experimental results concerning the amount of extractable substances and the color changes determined by the reaction of the tannins contained in wood with iron. Tests were performed comparatively with sapwood and heartwood samples of two Quercus species, namely Turkey oak (Quercus cerris L.) and sessile oak (Quercus petraea (Matt.) Liebl.). The findings show that Turkey oak sapwood has an unexpectedly high amount of extractable substances, higher than the heartwood of the same species. This result was obtained with three extraction methods (cold water, hot water, and NaOH 1% solution). The FTIR investigation of the extracts impregnated on quantitative filter paper seems to confirm these results. Visual assessment and color measurements after applying FeCl3 highlight that both oak species are prone to staining in contact with iron due to their tannin content. The values of the total color difference between the state and after the reaction with FeCl3, lower fer for Turkey oak compared to sessile oak, correlate with a lower extractive content of this wood species.","PeriodicalId":505399,"journal":{"name":"Bulletin of the Transilvania University of Brasov. Series II: Forestry • Wood Industry • Agricultural Food Engineering","volume":"11 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139167860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-21DOI: 10.31926/but.fwiafe.2023.16.65.3.15
Jr. Torcătoru, M.C. Timar
The paper presents an original laboratory method developed to determine and compare the light-induced colour changes of uncoated and coated wood surfaces, while also allowing the highlighting and evaluation of the individual contributions of the substrate and coating film to the global effect. Two types of wood test samples: V1 (uncoated) and V2 (coated) and coating films on 1mm thick clear glass slides were employed. The behaviour of the wood substrate under the coating film was simulated on uncoated substrate covered with a coated glass slide. European maple (Acer pseudoplatanus L.) and two types of transparent water-based varnishes with 2k formulations were used. The samples were exposed for up to 72 hours to artificial UV-VIS light in accelerated tests simulating natural light passing through window glass. Colour changes were measured in the CIELab system, as well as the chemical changes of the wood substrate and the coating films by FTIR analysis. Exposure of uncoated maple wood resulted in a total colour difference (E) of 10.83 units and this was only slightly reduced by coating (9.29-9.81 units). Exposure through the glass slide reduced the colour changes of the uncoated and coated wood surfaces by 37-43%. Colour changes of 5.79-6.85 units were measured on the wood substrate exposed under coated glass slides, whilst the colour changes of the coating films on glass slides were only 0.64-1.0 units, which indicates a maximum contribution of the wood substrate to the light-induced colour changes of the coated surfaces. FTIR investigation confirmed this finding.
{"title":"An Experimental Method to Evaluate the Contribution of Wood Substrate and Coating Film to the Light Induced Colour Changes of Wood Surfaces","authors":"Jr. Torcătoru, M.C. Timar","doi":"10.31926/but.fwiafe.2023.16.65.3.15","DOIUrl":"https://doi.org/10.31926/but.fwiafe.2023.16.65.3.15","url":null,"abstract":"The paper presents an original laboratory method developed to determine and compare the light-induced colour changes of uncoated and coated wood surfaces, while also allowing the highlighting and evaluation of the individual contributions of the substrate and coating film to the global effect. Two types of wood test samples: V1 (uncoated) and V2 (coated) and coating films on 1mm thick clear glass slides were employed. The behaviour of the wood substrate under the coating film was simulated on uncoated substrate covered with a coated glass slide. European maple (Acer pseudoplatanus L.) and two types of transparent water-based varnishes with 2k formulations were used. The samples were exposed for up to 72 hours to artificial UV-VIS light in accelerated tests simulating natural light passing through window glass. Colour changes were measured in the CIELab system, as well as the chemical changes of the wood substrate and the coating films by FTIR analysis. Exposure of uncoated maple wood resulted in a total colour difference (E) of 10.83 units and this was only slightly reduced by coating (9.29-9.81 units). Exposure through the glass slide reduced the colour changes of the uncoated and coated wood surfaces by 37-43%. Colour changes of 5.79-6.85 units were measured on the wood substrate exposed under coated glass slides, whilst the colour changes of the coating films on glass slides were only 0.64-1.0 units, which indicates a maximum contribution of the wood substrate to the light-induced colour changes of the coated surfaces. FTIR investigation confirmed this finding.","PeriodicalId":505399,"journal":{"name":"Bulletin of the Transilvania University of Brasov. Series II: Forestry • Wood Industry • Agricultural Food Engineering","volume":"25 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139167007","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-21DOI: 10.31926/but.fwiafe.2023.16.65.3.9
A. Ibrisevic, M. Obucina, S. Hajdarevic, G. Mihulja, M.K. Kuzman, I. Busuladzic
Computer Numerical Control (CNC) machines are increasingly popular in the production of furniture and wood products, because they combine high processing quality with short production time. The effective use of CNC machines depends on the processing parameters, which also affects the quality of the processed surface. The aim of this study was to determine the effect of feed rate, cutting direction, and grain direction on the surface roughness of various types of wood. Three European wood species (oak, beech, fir) were cut with a spindle speed of 16,000 rpm and two different feed rates (5,000 and 10,000 mm/min) using end mill tools on the CNC machine. The milling was performed in two cutting directions (radial and tangential) and two grain orientations (0° and 90°). An analysis of variance (ANOVA) was performed to evaluate the impact of the cutting parameters. The surface roughness measurements were taken, and two surface roughness parameters (Ra and Rz) were measured to determine the surface quality of the wood. According to the results of this study, the lowest surface roughness values, milling with the same processing parameters, occurred for oak wood, while the highest values occurred for fir.
{"title":"Effects of Cutting Parameters and Grain Direction on Surface Quality of Three Wood Species Obtained by CNC Milling","authors":"A. Ibrisevic, M. Obucina, S. Hajdarevic, G. Mihulja, M.K. Kuzman, I. Busuladzic","doi":"10.31926/but.fwiafe.2023.16.65.3.9","DOIUrl":"https://doi.org/10.31926/but.fwiafe.2023.16.65.3.9","url":null,"abstract":"Computer Numerical Control (CNC) machines are increasingly popular in the production of furniture and wood products, because they combine high processing quality with short production time. The effective use of CNC machines depends on the processing parameters, which also affects the quality of the processed surface. The aim of this study was to determine the effect of feed rate, cutting direction, and grain direction on the surface roughness of various types of wood. Three European wood species (oak, beech, fir) were cut with a spindle speed of 16,000 rpm and two different feed rates (5,000 and 10,000 mm/min) using end mill tools on the CNC machine. The milling was performed in two cutting directions (radial and tangential) and two grain orientations (0° and 90°). An analysis of variance (ANOVA) was performed to evaluate the impact of the cutting parameters. The surface roughness measurements were taken, and two surface roughness parameters (Ra and Rz) were measured to determine the surface quality of the wood. According to the results of this study, the lowest surface roughness values, milling with the same processing parameters, occurred for oak wood, while the highest values occurred for fir.","PeriodicalId":505399,"journal":{"name":"Bulletin of the Transilvania University of Brasov. Series II: Forestry • Wood Industry • Agricultural Food Engineering","volume":"26 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139166998","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-21DOI: 10.31926/but.fwiafe.2023.16.65.3.5
N. Deliiski, L. Dzurenda, P. Niemz, M. Campean, D. Angelski, P. Vitchev
This paper presents an approach for computing the heat balance of boiling pits during the plasticizing of non-frozen logs intended for the production of peeled veneer. With the help of our non-stationary model, the heating times of beech logs with a diameter of 0.4 m, an initial temperature of 10°C, and a moisture content of 0.6 kg∙kg-1 were determined at water temperatures in the pit equal to 70, 80, and 90°C. Using the determined logs’ boiling durations and the mentioned approach, the change in the total energy required to carry out the entire boiling process and that required for each of the individual components of the heat balance was calculated. Computer simulations were conducted for a concrete pit with overall dimensions of 8.0 × 2.6 x 2.5 m, a working volume of 20 m3, and a degree of filling with logs equal to 45, 60, and 75%. It was found that the increase in the water temperature from 70 to 90°C causes an increase in the total specific energy, as well as in the energy for the heating of the logs themselves, the construction, and the water of the pit. At the same time, the energy required to cover the heat losses of the pit decreases and the energy for heating the metal heater/radiator itself does not change. A decrease in the degree of filling of the pit with logs from 75 to 45% causes an increase in both the total energy and all its components except the energy for heating the logs, which remains unchanged.
{"title":"A Simulation Study of the Heat Balance of Concrete Pits During Boiling of Non-Frozen Logs","authors":"N. Deliiski, L. Dzurenda, P. Niemz, M. Campean, D. Angelski, P. Vitchev","doi":"10.31926/but.fwiafe.2023.16.65.3.5","DOIUrl":"https://doi.org/10.31926/but.fwiafe.2023.16.65.3.5","url":null,"abstract":"This paper presents an approach for computing the heat balance of boiling pits during the plasticizing of non-frozen logs intended for the production of peeled veneer. With the help of our non-stationary model, the heating times of beech logs with a diameter of 0.4 m, an initial temperature of 10°C, and a moisture content of 0.6 kg∙kg-1 were determined at water temperatures in the pit equal to 70, 80, and 90°C. Using the determined logs’ boiling durations and the mentioned approach, the change in the total energy required to carry out the entire boiling process and that required for each of the individual components of the heat balance was calculated. Computer simulations were conducted for a concrete pit with overall dimensions of 8.0 × 2.6 x 2.5 m, a working volume of 20 m3, and a degree of filling with logs equal to 45, 60, and 75%. It was found that the increase in the water temperature from 70 to 90°C causes an increase in the total specific energy, as well as in the energy for the heating of the logs themselves, the construction, and the water of the pit. At the same time, the energy required to cover the heat losses of the pit decreases and the energy for heating the metal heater/radiator itself does not change. A decrease in the degree of filling of the pit with logs from 75 to 45% causes an increase in both the total energy and all its components except the energy for heating the logs, which remains unchanged.","PeriodicalId":505399,"journal":{"name":"Bulletin of the Transilvania University of Brasov. Series II: Forestry • Wood Industry • Agricultural Food Engineering","volume":"21 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139167611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-21DOI: 10.31926/but.fwiafe.2023.16.65.3.10
Mark Irle, Flore Lebreton, Marie Kutter
The Horizon Europe funded EcoReFibre project (www.ecorefibre.eu) is concerned with recycling fibreboards and, in particular, Medium Density Fibreboard. This paper covers our research on determining the typical lifespans of products containing fibreboard. Knowing the lifespan of a product is important as it is the main determining factor that influences the age when it becomes waste. This paper proposes that the average age at which a product containing MDF becomes waste is between 10.7 and 12.1 years.
{"title":"The Lifespans of Products Made with MDF","authors":"Mark Irle, Flore Lebreton, Marie Kutter","doi":"10.31926/but.fwiafe.2023.16.65.3.10","DOIUrl":"https://doi.org/10.31926/but.fwiafe.2023.16.65.3.10","url":null,"abstract":"The Horizon Europe funded EcoReFibre project (www.ecorefibre.eu) is concerned with recycling fibreboards and, in particular, Medium Density Fibreboard. This paper covers our research on determining the typical lifespans of products containing fibreboard. Knowing the lifespan of a product is important as it is the main determining factor that influences the age when it becomes waste. This paper proposes that the average age at which a product containing MDF becomes waste is between 10.7 and 12.1 years.","PeriodicalId":505399,"journal":{"name":"Bulletin of the Transilvania University of Brasov. Series II: Forestry • Wood Industry • Agricultural Food Engineering","volume":"9 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139167800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-21DOI: 10.31926/but.fwiafe.2023.16.65.3.12
A. Lungu, L. Gurău, C. Coșereanu, Camelia Coșoreanu
The paper presents an experimental investigation of the quality of CNC routed surfaces with a V-Grooving router bit (90°) on various milling angles as a function of wood grain direction on beech (Fagus sylvatica L.) wood. The quality of the machined surface was first visually assessed for the presence of raised fibre and other processing defects on the routed circles with a diameter of 180 mm using feed speeds of 3 m/min and 6 m/min respectively, and spindle speeds of 12,000, 15,000, and 18,000 rpm. The quality of the processed surfaces on the circle indicated the most unfavourable CNC routing regime accompanied by the conclusions regarding the most unfavourable angles related to the grain. Further research considered the assessment of the surface quality on straight CNC routing with angles of 0, 15, 30, 45, 60, 75, and 90° related to the wood grain direction at feed speeds of 3 and 6 m/min and spindle speed of 15,000 rpm. In this case, the characterisation of the wood surface quality was made by measuring the roughness parameters. The highest values of the roughness parameters, showing the presence of the fibres detached from the surface, were recorded for the cutting angle of 60, followed closely by 75°, then 45°, and 90° at a feed speed of 3 m/min. No significant difference was found between the Rk of the cutting angles from 0° to 45°, but it increased significantly for 60, 75, and 90°, showing frequent deeper anatomical voids on the surface.
{"title":"Evaluation of CNC Routed Surface Quality of Beech (Fagus sylvatica L.) with Different Milling Angles as Function of Grain Orientation","authors":"A. Lungu, L. Gurău, C. Coșereanu, Camelia Coșoreanu","doi":"10.31926/but.fwiafe.2023.16.65.3.12","DOIUrl":"https://doi.org/10.31926/but.fwiafe.2023.16.65.3.12","url":null,"abstract":"The paper presents an experimental investigation of the quality of CNC routed surfaces with a V-Grooving router bit (90°) on various milling angles as a function of wood grain direction on beech (Fagus sylvatica L.) wood. The quality of the machined surface was first visually assessed for the presence of raised fibre and other processing defects on the routed circles with a diameter of 180 mm using feed speeds of 3 m/min and 6 m/min respectively, and spindle speeds of 12,000, 15,000, and 18,000 rpm. The quality of the processed surfaces on the circle indicated the most unfavourable CNC routing regime accompanied by the conclusions regarding the most unfavourable angles related to the grain. Further research considered the assessment of the surface quality on straight CNC routing with angles of 0, 15, 30, 45, 60, 75, and 90° related to the wood grain direction at feed speeds of 3 and 6 m/min and spindle speed of 15,000 rpm. In this case, the characterisation of the wood surface quality was made by measuring the roughness parameters. The highest values of the roughness parameters, showing the presence of the fibres detached from the surface, were recorded for the cutting angle of 60, followed closely by 75°, then 45°, and 90° at a feed speed of 3 m/min. No significant difference was found between the Rk of the cutting angles from 0° to 45°, but it increased significantly for 60, 75, and 90°, showing frequent deeper anatomical voids on the surface.","PeriodicalId":505399,"journal":{"name":"Bulletin of the Transilvania University of Brasov. Series II: Forestry • Wood Industry • Agricultural Food Engineering","volume":"5 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139167882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-21DOI: 10.31926/but.fwiafe.2023.16.65.3.11
K. Kosutova, L.M. Osvaldova
By choosing suitable individual building materials for a sandwich structure, we can ensure an increase in the fire resistance of the entire structure. The influence of the properties of individual building materials on the overall fire resistance in sandwich constructions has not been well researched. It is for this reason that we focus our contribution on the influence of the properties of building materials in wooden sandwich structures on overall fire resistance. In the wooden sandwich constructions we created, we worked with reference constructions composed of thermal insulation with different surface treatments and with constructions that have the same thermal insulation, but we added 40 mm thick mineral wool to them. Subsequently, we tested the structures according to the EN 1365-1 standard [4]. After processing the obtained results, we came to conclusions about the effect of mineral wool and its combination with suitable thermal insulation on overall fire resistance.
通过为夹层结构选择合适的单个建筑材料，我们可以确保提高整个结构的耐火性。关于个别建筑材料的特性对夹层结构整体耐火性的影响，目前还没有很好的研究。因此，我们重点研究了木质夹层结构中建筑材料的特性对整体耐火性的影响。在我们创建的木质夹层结构中，我们使用了由不同表面处理的隔热材料组成的参考结构，以及具有相同隔热材料但添加了 40 毫米厚矿棉的结构。随后，我们根据 EN 1365-1 标准[4]对这些结构进行了测试。在对所得结果进行处理后，我们得出了矿棉及其与适当隔热材料的组合对整体耐火性的影响的结论。
{"title":"Influence of Properties of Building Materials in Wooden Sandwich Constructions on Overall Fire Resistance","authors":"K. Kosutova, L.M. Osvaldova","doi":"10.31926/but.fwiafe.2023.16.65.3.11","DOIUrl":"https://doi.org/10.31926/but.fwiafe.2023.16.65.3.11","url":null,"abstract":"By choosing suitable individual building materials for a sandwich structure, we can ensure an increase in the fire resistance of the entire structure. The influence of the properties of individual building materials on the overall fire resistance in sandwich constructions has not been well researched. It is for this reason that we focus our contribution on the influence of the properties of building materials in wooden sandwich structures on overall fire resistance. In the wooden sandwich constructions we created, we worked with reference constructions composed of thermal insulation with different surface treatments and with constructions that have the same thermal insulation, but we added 40 mm thick mineral wool to them. Subsequently, we tested the structures according to the EN 1365-1 standard [4]. After processing the obtained results, we came to conclusions about the effect of mineral wool and its combination with suitable thermal insulation on overall fire resistance.","PeriodicalId":505399,"journal":{"name":"Bulletin of the Transilvania University of Brasov. Series II: Forestry • Wood Industry • Agricultural Food Engineering","volume":"60 170","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139166714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-21DOI: 10.31926/but.fwiafe.2023.16.65.3.13
M. Petrič, J. Levanic, D. Paul
Over the past 50 years, instrumented indentation, in which an indenter tip probes the specimen surface with a regulated force and displacement to characterize its mechanical properties, has evolved. With the development of atomic force microscopy, instrumented nanoindentation has been extensively applied, and instrumented indentation in the micro range (micro-indentation) has been somewhat overshadowed by nanoindentation. However, micro-indentation remains an extremely useful technique that has the potential to investigate various properties of surface treated wood. In the first, overview-type part of the paper, instrumented micro-indentation is described and some examples of its possible applications in the field of wood science and technology are presented. To illustrate the importance of this experimental technique, some results of micro-indentation experiments carried out in our wood surface treatment laboratory are shown in the second part of the paper. The objects of the tests were untreated Scots pine wood and Scots pine wood with surface deposits of SiO2 or ZnO. The differences between the mechanical properties of early and latewood could be clearly distinguished by the micro indentation technique. On the other hand, the influence of ZnO and SiO2 particles on mechanical properties as a function of indentation depth could not be detected by this technique.
{"title":"Investigations of Surface-Treated Wood by a Micro-Indentation Approach: A Short Review and a Case Study","authors":"M. Petrič, J. Levanic, D. Paul","doi":"10.31926/but.fwiafe.2023.16.65.3.13","DOIUrl":"https://doi.org/10.31926/but.fwiafe.2023.16.65.3.13","url":null,"abstract":"Over the past 50 years, instrumented indentation, in which an indenter tip probes the specimen surface with a regulated force and displacement to characterize its mechanical properties, has evolved. With the development of atomic force microscopy, instrumented nanoindentation has been extensively applied, and instrumented indentation in the micro range (micro-indentation) has been somewhat overshadowed by nanoindentation. However, micro-indentation remains an extremely useful technique that has the potential to investigate various properties of surface treated wood. In the first, overview-type part of the paper, instrumented micro-indentation is described and some examples of its possible applications in the field of wood science and technology are presented. To illustrate the importance of this experimental technique, some results of micro-indentation experiments carried out in our wood surface treatment laboratory are shown in the second part of the paper. The objects of the tests were untreated Scots pine wood and Scots pine wood with surface deposits of SiO2 or ZnO. The differences between the mechanical properties of early and latewood could be clearly distinguished by the micro indentation technique. On the other hand, the influence of ZnO and SiO2 particles on mechanical properties as a function of indentation depth could not be detected by this technique.","PeriodicalId":505399,"journal":{"name":"Bulletin of the Transilvania University of Brasov. Series II: Forestry • Wood Industry • Agricultural Food Engineering","volume":"38 19","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139166763","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-21DOI: 10.31926/but.fwiafe.2023.16.65.3.14
V. Savov, D. Hristodorova
Wood-based panels are one of the leading materials for frame structures of furniture. The worldwide shortage of wood raw materials necessitates searching for alternative sources to produce panels. Hemp shives are a representative of precisely this type of raw material. They are characterised by low bulk density and high fibre strength. For this study, four types of one-layered panels from hemp shives were fabricated in laboratory conditions, with a resin content of 8, 10, 12, and 14%, respectively. Accordingly, their main physical and mechanical properties were determined and compared to those of particleboards from raw wood material. It was found that the obtained panels from hemp shives have very good mechanical properties, and their high edge screw withdrawal resistance is very promising in terms of applicability for furniture constructions. As a direct result of these findings, the resin content is not recommended to be above 10%.
{"title":"Properties of Hemp Shive Panels with Different Resin Content","authors":"V. Savov, D. Hristodorova","doi":"10.31926/but.fwiafe.2023.16.65.3.14","DOIUrl":"https://doi.org/10.31926/but.fwiafe.2023.16.65.3.14","url":null,"abstract":"Wood-based panels are one of the leading materials for frame structures of furniture. The worldwide shortage of wood raw materials necessitates searching for alternative sources to produce panels. Hemp shives are a representative of precisely this type of raw material. They are characterised by low bulk density and high fibre strength. For this study, four types of one-layered panels from hemp shives were fabricated in laboratory conditions, with a resin content of 8, 10, 12, and 14%, respectively. Accordingly, their main physical and mechanical properties were determined and compared to those of particleboards from raw wood material. It was found that the obtained panels from hemp shives have very good mechanical properties, and their high edge screw withdrawal resistance is very promising in terms of applicability for furniture constructions. As a direct result of these findings, the resin content is not recommended to be above 10%.","PeriodicalId":505399,"journal":{"name":"Bulletin of the Transilvania University of Brasov. Series II: Forestry • Wood Industry • Agricultural Food Engineering","volume":"6 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139167370","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-21DOI: 10.31926/but.fwiafe.2023.16.65.3.3
Marlene Cramer
Recent research in Europe is bringing a wider range of wood species to the construction market as structural timber and glue laminated products. This option would also open markets for currently underused UK species, foremost hardwoods, but testing efforts when developing strength grading assignments for any minor UK species are prohibitive, as the resource is small and scattered. Grading approaches that require less material for destructive testing could be employed to open routes to market for structural hardwood products. In addition, the European hardwood research has revealed some gaps and uncertainties in grading standards. In particular, data are lacking to support adjustment equations for size, moisture content, and testing arrangement for hardwoods. This paper outlines a new PhD project that will focus on these problems and aims to develop an easier route for strength grading hardwoods.
{"title":"The Challenge of Strength Grading UK Hardwoods","authors":"Marlene Cramer","doi":"10.31926/but.fwiafe.2023.16.65.3.3","DOIUrl":"https://doi.org/10.31926/but.fwiafe.2023.16.65.3.3","url":null,"abstract":"Recent research in Europe is bringing a wider range of wood species to the construction market as structural timber and glue laminated products. This option would also open markets for currently underused UK species, foremost hardwoods, but testing efforts when developing strength grading assignments for any minor UK species are prohibitive, as the resource is small and scattered. Grading approaches that require less material for destructive testing could be employed to open routes to market for structural hardwood products. In addition, the European hardwood research has revealed some gaps and uncertainties in grading standards. In particular, data are lacking to support adjustment equations for size, moisture content, and testing arrangement for hardwoods. This paper outlines a new PhD project that will focus on these problems and aims to develop an easier route for strength grading hardwoods.","PeriodicalId":505399,"journal":{"name":"Bulletin of the Transilvania University of Brasov. Series II: Forestry • Wood Industry • Agricultural Food Engineering","volume":"31 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139167566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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