Pub Date : 2022-07-15DOI: 10.5552/drvind.2022.0016
J. Miklečić, Andrea Lončarić, Nikolina Veseličić, V. Jirouš-Rajković
In this research, the influence of face milling, sanding and UV irradiation of the hornbeam and ash wood sample on the wetting and adhesion strength of solvent-based and water-borne coating was studied. The adhesion of coatings to substrates is one of the most important parameters for finishing quality and service life of wood coatings, while wetting properties are usually used to assess the quality of surfacing process and could also provide important information on the adhesion ability of coatings. Surface roughness, contact angle of coatings and water as well as adhesion strength of coatings were tested on differently prepared (face milled, sanded and UV irradiated) samples of unmodified and thermally modified ash and hornbeam wood. Surface roughness was measured with stylus-type profilometer over the traverse of 12.5 mm and with a cut-off value of 2.5. Contact angle was measured using the sessile drop method 2 s, 10 s and 30 s after the application of the liquid drop on the sample surface, and adhesion strength was measured according to ASTM D4541. Results showed that sanding of hornbeam and ash wood resulted in the least rough surface compared to the face milled and UV irradiated surface. Contact angles of the water-borne coating were on average three times higher than the contact angles of the solvent-based coating. Sanding the surface of hornbeam and ash samples increased the adhesive strength in relation to the face milled surface, while UV irradiation of the sanded surface decreased the adhesive strength of most samples coated with solvent-based coating.
{"title":"Influence of Wood Surface Preparation on Roughness, Wettability and Coating Adhesion of Unmodified and Thermally Modified Wood","authors":"J. Miklečić, Andrea Lončarić, Nikolina Veseličić, V. Jirouš-Rajković","doi":"10.5552/drvind.2022.0016","DOIUrl":"https://doi.org/10.5552/drvind.2022.0016","url":null,"abstract":"In this research, the influence of face milling, sanding and UV irradiation of the hornbeam and ash wood sample on the wetting and adhesion strength of solvent-based and water-borne coating was studied. The adhesion of coatings to substrates is one of the most important parameters for finishing quality and service life of wood coatings, while wetting properties are usually used to assess the quality of surfacing process and could also provide important information on the adhesion ability of coatings. Surface roughness, contact angle of coatings and water as well as adhesion strength of coatings were tested on differently prepared (face milled, sanded and UV irradiated) samples of unmodified and thermally modified ash and hornbeam wood. Surface roughness was measured with stylus-type profilometer over the traverse of 12.5 mm and with a cut-off value of 2.5. Contact angle was measured using the sessile drop method 2 s, 10 s and 30 s after the application of the liquid drop on the sample surface, and adhesion strength was measured according to ASTM D4541. Results showed that sanding of hornbeam and ash wood resulted in the least rough surface compared to the face milled and UV irradiated surface. Contact angles of the water-borne coating were on average three times higher than the contact angles of the solvent-based coating. Sanding the surface of hornbeam and ash samples increased the adhesive strength in relation to the face milled surface, while UV irradiation of the sanded surface decreased the adhesive strength of most samples coated with solvent-based coating.","PeriodicalId":11427,"journal":{"name":"Drvna Industrija","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2022-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43182075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-15DOI: 10.5552/drvind.2022.0023
D. Jokanović, T. Ćirković-Mitrović, Vesna Nikolić Jokanović, R. Lozjanin, I. Ištok
Anatomical properties of pedunculate oak (Quercus robur L.) wood have not been previously investigated in Serbia, so bearing in mind economic-productive and ecological significance of this species, it was one of the main reasons why this research was conducted. In this paper, fibre length (FL), double cell-wall thickness (DCWT) and fibre lumen diameter (FLD) were measured in pedunculate oak wood from two different sites. The study was conducted at two sites (Donji Srem – MU „Raškovica-Smogvica” and Gornji Srem – MU „Kupinske grede”), situated along the Sava River and characterised by different ecological conditions, including flooding regimes. Measurements were conducted in radial direction, from pith to bark, in order to assess variation of investigated characteristics with cambial age, between two sites and between individual trees within each site. All measured characteristics from both sites increase going from pith to bark apart from FL in the area of Donji Srem – MU „Kupinske grede” that reaches maximum value in the central part of xylem and then decreases. Hydrological site conditions affect the dimensions of pedunculate oak wood fibres and these values are a bit higher in Gornji Srem – MU „Raškovica-Smogvica”, due to a greater quantity of available water.
{"title":"Wood Fibre Characteristics of Pedunculate Oak (Quercus R obur L.) Growing in Different Ecological Conditions","authors":"D. Jokanović, T. Ćirković-Mitrović, Vesna Nikolić Jokanović, R. Lozjanin, I. Ištok","doi":"10.5552/drvind.2022.0023","DOIUrl":"https://doi.org/10.5552/drvind.2022.0023","url":null,"abstract":"Anatomical properties of pedunculate oak (Quercus robur L.) wood have not been previously investigated in Serbia, so bearing in mind economic-productive and ecological significance of this species, it was one of the main reasons why this research was conducted. In this paper, fibre length (FL), double cell-wall thickness (DCWT) and fibre lumen diameter (FLD) were measured in pedunculate oak wood from two different sites. The study was conducted at two sites (Donji Srem – MU „Raškovica-Smogvica” and Gornji Srem – MU „Kupinske grede”), situated along the Sava River and characterised by different ecological conditions, including flooding regimes. Measurements were conducted in radial direction, from pith to bark, in order to assess variation of investigated characteristics with cambial age, between two sites and between individual trees within each site. All measured characteristics from both sites increase going from pith to bark apart from FL in the area of Donji Srem – MU „Kupinske grede” that reaches maximum value in the central part of xylem and then decreases. Hydrological site conditions affect the dimensions of pedunculate oak wood fibres and these values are a bit higher in Gornji Srem – MU „Raškovica-Smogvica”, due to a greater quantity of available water.","PeriodicalId":11427,"journal":{"name":"Drvna Industrija","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2022-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42564678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-15DOI: 10.5552/drvind.2022.0027
Marta Pędzik, Zdzisław Kwidziński, T. Rogoziński
Problems with the availability of particleboards are a challenge for constructors and production companies that use this material in the technology of their products. During the production process of technical door leaves, a significant amount of wood-based panel residues is created, which is a large base of potential raw material on an annual basis. Given the conceptual link between circular economy (CE) activities, resources, and waste management, efforts should be made to process and reuse them to produce new particleboards. The aim of the study was to determine the physical and hygienic properties of particles obtained from the grinding of lignocellulosic composites used in production. It was found that in terms of dimensions, density as well as formaldehyde content, they have the potential to be an alternative source of raw material for the production of particleboards. However, selecting the type of materials should be carried out, and in the future, the hygienic properties of the manufactured particleboards should be controlled.
{"title":"Particles from Residue Wood-Based Materials from Door Production as an Alternative Raw Material for Production of Particleboard","authors":"Marta Pędzik, Zdzisław Kwidziński, T. Rogoziński","doi":"10.5552/drvind.2022.0027","DOIUrl":"https://doi.org/10.5552/drvind.2022.0027","url":null,"abstract":"Problems with the availability of particleboards are a challenge for constructors and production companies that use this material in the technology of their products. During the production process of technical door leaves, a significant amount of wood-based panel residues is created, which is a large base of potential raw material on an annual basis. Given the conceptual link between circular economy (CE) activities, resources, and waste management, efforts should be made to process and reuse them to produce new particleboards. The aim of the study was to determine the physical and hygienic properties of particles obtained from the grinding of lignocellulosic composites used in production. It was found that in terms of dimensions, density as well as formaldehyde content, they have the potential to be an alternative source of raw material for the production of particleboards. However, selecting the type of materials should be carried out, and in the future, the hygienic properties of the manufactured particleboards should be controlled.","PeriodicalId":11427,"journal":{"name":"Drvna Industrija","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2022-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49232948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-15DOI: 10.5552/drvind.2022.0018
L. Javorek, R. Kminiak, M. Vargovská, E. Csanády, S. Németh
The monitoring of cutting force components is one of the possibilities to control machining processes from the point of view of its stability, machine tool spindle or cutting tool loading. This paper presents and compares the results of experimental longitudinal sawing of pine wood with 4 saw discs with different teeth number (16 and 24) and rake angle (10° and 20°) during up (conventional) and down (climb) cutting with different revolutions (4000 min-1, 5000 min-1, 6000 min-1) and feed speed (15 m/min, 20 m/min, 25 m/min). The signal was obtained from Quart 3-components piezoelectric dynamometer.
{"title":"Feed Cutting Force Component in Up and Down Sawing of Pine","authors":"L. Javorek, R. Kminiak, M. Vargovská, E. Csanády, S. Németh","doi":"10.5552/drvind.2022.0018","DOIUrl":"https://doi.org/10.5552/drvind.2022.0018","url":null,"abstract":"The monitoring of cutting force components is one of the possibilities to control machining processes from the point of view of its stability, machine tool spindle or cutting tool loading. This paper presents and compares the results of experimental longitudinal sawing of pine wood with 4 saw discs with different teeth number (16 and 24) and rake angle (10° and 20°) during up (conventional) and down (climb) cutting with different revolutions (4000 min-1, 5000 min-1, 6000 min-1) and feed speed (15 m/min, 20 m/min, 25 m/min). The signal was obtained from Quart 3-components piezoelectric dynamometer.","PeriodicalId":11427,"journal":{"name":"Drvna Industrija","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2022-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42493702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-15DOI: 10.5552/drvind.2022.0024
Michał Słonina, J. Smardzewski
The study aimed to determine the effect of impregnation with modified starch of recycled paper (Testliner) on elasticity constants of slender core cells and the influence on the elasticity constants and strength of honeycomb with facings made of thin particleboards. The experimental tests were carried out on beams subjected to three-point bending. It was shown that slender hexagonal cells significantly differentiate their elastic properties and elastic properties of honeycomb panels in the main directions of orthotropy. Impregnation of the Testliner paper with modified starch reduces the values of the modulus of elasticity of the cells by about 8.8 % and reduces the values of the modulus of elasticity of the honeycomb panels by at least 6.9 %. Analytical solutions that do not take into account the structural form of the core cannot be used to calculate the modulus of elasticity of sandwich panels with hexagonal core cells.
{"title":"Starch Impregnation Effect of Testliner Paper on Stiffness of Honeycomb Panels with Slender Cells","authors":"Michał Słonina, J. Smardzewski","doi":"10.5552/drvind.2022.0024","DOIUrl":"https://doi.org/10.5552/drvind.2022.0024","url":null,"abstract":"The study aimed to determine the effect of impregnation with modified starch of recycled paper (Testliner) on elasticity constants of slender core cells and the influence on the elasticity constants and strength of honeycomb with facings made of thin particleboards. The experimental tests were carried out on beams subjected to three-point bending. It was shown that slender hexagonal cells significantly differentiate their elastic properties and elastic properties of honeycomb panels in the main directions of orthotropy. Impregnation of the Testliner paper with modified starch reduces the values of the modulus of elasticity of the cells by about 8.8 % and reduces the values of the modulus of elasticity of the honeycomb panels by at least 6.9 %. Analytical solutions that do not take into account the structural form of the core cannot be used to calculate the modulus of elasticity of sandwich panels with hexagonal core cells.","PeriodicalId":11427,"journal":{"name":"Drvna Industrija","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2022-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46527090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-15DOI: 10.5552/drvind.2022.0022
K. Orłowski, D. Chuchala, G. Sinn
The determination of energy effects for wood machining processes, such as cutting power and cutting forces, is very useful in designing of manufacture process of wooden products. A more accurate prediction of cutting forces requires a correct determination of the shear angle value, which can be determined using various models. In this article, shear angle values for an orthogonal linear cutting process of pine wood are determined. The pine wood analysed was represented by two groups of samples with different moisture content levels, 12 % and 20 %. Three different models were used to determine the shear angle values: the Merchant model, which is based on the rake angle and the angle of friction, model based on chip compression ratios and Atkins model based on material properties (elements of fracture mechanics). The values obtained have been analysed for comparison. Results showed that the values of the shearing angles determined from the chip compression ratios turned out to be higher than the values from Merchant equation. The shear angles determined from the Atkins model are, as expected, lower than those determined from the Merchant model. Furthermore, the shear angle values for moisture content of 20 % are higher than for moisture content of 12 %.
{"title":"Analyses of Shear Angle in Orthogonal Cutting of Pine Wood","authors":"K. Orłowski, D. Chuchala, G. Sinn","doi":"10.5552/drvind.2022.0022","DOIUrl":"https://doi.org/10.5552/drvind.2022.0022","url":null,"abstract":"The determination of energy effects for wood machining processes, such as cutting power and cutting forces, is very useful in designing of manufacture process of wooden products. A more accurate prediction of cutting forces requires a correct determination of the shear angle value, which can be determined using various models. In this article, shear angle values for an orthogonal linear cutting process of pine wood are determined. The pine wood analysed was represented by two groups of samples with different moisture content levels, 12 % and 20 %. Three different models were used to determine the shear angle values: the Merchant model, which is based on the rake angle and the angle of friction, model based on chip compression ratios and Atkins model based on material properties (elements of fracture mechanics). The values obtained have been analysed for comparison. Results showed that the values of the shearing angles determined from the chip compression ratios turned out to be higher than the values from Merchant equation. The shear angles determined from the Atkins model are, as expected, lower than those determined from the Merchant model. Furthermore, the shear angle values for moisture content of 20 % are higher than for moisture content of 12 %.","PeriodicalId":11427,"journal":{"name":"Drvna Industrija","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2022-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41951753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-15DOI: 10.5552/drvind.2022.0017
E. Skorupińska, K. Wiaderek, M. Sydor
T-nuts are factory installed in the holes of the ready-to-assemble furniture components. There is a risk that the t-nut spontaneously falls out during transport or storage and get lost; the t-nut can also be pushed into inaccessible spaces during assembly. These complications can make furniture assembly impossible. For this reason, sufficient force to hold the t-nut in the hole is essential. The article presents the test results of the forces holding the t-nuts in five furniture materials (softwood, Oriented Strand Board, plywood, and particleboard in two variants). The M6 t-nuts with four prongs were installed in predrilled 8 mm holes. The resistance to withdrawal of the t-nuts was measured with a universal testing machine. The tested materials could be divided into three groups in terms of the risk of the t-nut falling out: softwood and plywood – low risk, F = 1113.2-1158.0 N; OSB and particleboard – moderate risk, F = 592.3-645.5 N, particleboard with a pad – high risk, F = 645.5 N. The results show that the withdrawal resistance is not correlated with the density of the wood material, and that it decreased with the degree of wood material processing – the less processed the material, the greater the resistance to withdrawal of the t-nuts.
{"title":"Withdrawal Resistance of T-Nuts in Various Furniture Materials","authors":"E. Skorupińska, K. Wiaderek, M. Sydor","doi":"10.5552/drvind.2022.0017","DOIUrl":"https://doi.org/10.5552/drvind.2022.0017","url":null,"abstract":"T-nuts are factory installed in the holes of the ready-to-assemble furniture components. There is a risk that the t-nut spontaneously falls out during transport or storage and get lost; the t-nut can also be pushed into inaccessible spaces during assembly. These complications can make furniture assembly impossible. For this reason, sufficient force to hold the t-nut in the hole is essential. The article presents the test results of the forces holding the t-nuts in five furniture materials (softwood, Oriented Strand Board, plywood, and particleboard in two variants). The M6 t-nuts with four prongs were installed in predrilled 8 mm holes. The resistance to withdrawal of the t-nuts was measured with a universal testing machine. The tested materials could be divided into three groups in terms of the risk of the t-nut falling out: softwood and plywood – low risk, F = 1113.2-1158.0 N; OSB and particleboard – moderate risk, F = 592.3-645.5 N, particleboard with a pad – high risk, F = 645.5 N. The results show that the withdrawal resistance is not correlated with the density of the wood material, and that it decreased with the degree of wood material processing – the less processed the material, the greater the resistance to withdrawal of the t-nuts.","PeriodicalId":11427,"journal":{"name":"Drvna Industrija","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2022-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49308748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-15DOI: 10.5552/drvind.2022.0025
M. Wieruszewski, Z. Malinowski, R. Mirski
Changes in the processing directions of round wood require the selection of raw material with appropriate quality and dimensional characteristics. In the case of large-size pine wood, these parameters translate significantly into its value and material indicators. The purpose of the research was to verify the currently applied classification principles with respect to the expectations of the market of wood industry customers. The research was conducted using the direct survey method, taking into account the structure of processing and sorting of production of wood industry representatives. The basic dimensional and quality groups for coniferous wood were separated, with wood defects assigned to them, in accordance with the currently binding principles of the quality and dimensional classification conducted by the State Forests. The respondents pointed out the necessity of changes in the minimum dimensions for wood of higher quality classes and changes in admissibility of selected defects in wood of lower classes.
{"title":"Quality and Dimensional Parameters of Large-Sized Pine Timber in View of Expectations of Polish Sawmill Industry","authors":"M. Wieruszewski, Z. Malinowski, R. Mirski","doi":"10.5552/drvind.2022.0025","DOIUrl":"https://doi.org/10.5552/drvind.2022.0025","url":null,"abstract":"Changes in the processing directions of round wood require the selection of raw material with appropriate quality and dimensional characteristics. In the case of large-size pine wood, these parameters translate significantly into its value and material indicators. The purpose of the research was to verify the currently applied classification principles with respect to the expectations of the market of wood industry customers. The research was conducted using the direct survey method, taking into account the structure of processing and sorting of production of wood industry representatives. The basic dimensional and quality groups for coniferous wood were separated, with wood defects assigned to them, in accordance with the currently binding principles of the quality and dimensional classification conducted by the State Forests. The respondents pointed out the necessity of changes in the minimum dimensions for wood of higher quality classes and changes in admissibility of selected defects in wood of lower classes.","PeriodicalId":11427,"journal":{"name":"Drvna Industrija","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2022-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44919701","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-15DOI: 10.5552/drvind.2022.0021
J. Majka, M. Sydor, Jakub Prentki, M. Zborowska
The research aimed to obtain empirical data for modeling the initial desorption in reaction wood from the cross-section of the green beech (Fagus sylvatica L.) log. Firstly, we analyzed the chemical composition, macro and microscopic structure of tension and opposite wood tissue. Then, the Equilibrium Moisture Content (EMC) was measured by the Dynamic Vapor Sorption method during the initial desorption. The used air parameters were specific for the mild drying schedule of green beech timber (t = 20, 35, and 50 °C, Relative Humidity (RH) ranging from 95 to 0 %). Relationships between the EMC of reaction wood and drying parameters were modeled using the Response Surface Method (RSM). The tests revealed: different hygroscopic properties of tension and opposite wood, the dependence of EMC value on temperature, and differences between EMC values for initial (first) and second desorption. Moreover, it was confirmed that, during initial desorption, the EMCs of reaction wood are significantly higher than reference EMC data. The differences in the EMC value are up to 0.14 kg/kg (for air with RH above 90 %). The presented polynomial model of the initial desorption of reaction beech wood can improve drying schedules for beech sawn timber with a high amount of reaction tissue.
{"title":"Initial Desorption of Reaction Beech Wood","authors":"J. Majka, M. Sydor, Jakub Prentki, M. Zborowska","doi":"10.5552/drvind.2022.0021","DOIUrl":"https://doi.org/10.5552/drvind.2022.0021","url":null,"abstract":"The research aimed to obtain empirical data for modeling the initial desorption in reaction wood from the cross-section of the green beech (Fagus sylvatica L.) log. Firstly, we analyzed the chemical composition, macro and microscopic structure of tension and opposite wood tissue. Then, the Equilibrium Moisture Content (EMC) was measured by the Dynamic Vapor Sorption method during the initial desorption. The used air parameters were specific for the mild drying schedule of green beech timber (t = 20, 35, and 50 °C, Relative Humidity (RH) ranging from 95 to 0 %). Relationships between the EMC of reaction wood and drying parameters were modeled using the Response Surface Method (RSM). The tests revealed: different hygroscopic properties of tension and opposite wood, the dependence of EMC value on temperature, and differences between EMC values for initial (first) and second desorption. Moreover, it was confirmed that, during initial desorption, the EMCs of reaction wood are significantly higher than reference EMC data. The differences in the EMC value are up to 0.14 kg/kg (for air with RH above 90 %). The presented polynomial model of the initial desorption of reaction beech wood can improve drying schedules for beech sawn timber with a high amount of reaction tissue.","PeriodicalId":11427,"journal":{"name":"Drvna Industrija","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2022-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45591905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-15DOI: 10.5552/drvind.2022.0019
L. Dzurenda, Michal Dudiak
Alder wood (Alnus glutinosa L.) was steamed with a saturated steam-air mixture at a temperature of t = 95 °C, or saturated steam at t = 115 °C and t = 135 °C to obtain a pale brown colour, a light red-brown colour and a dark brown-grey colour. Subsequently, samples of unsteamed and steamed alder wood were irradiated with a UV lamp in a Xenotest Q-SUN Xe-3-HS after drying in order to test the colour stability of steamed alder wood. The colour change of the wood surface was evaluated by means of measured values on the coordinates of the colour space CIE L*a*b*. The results show that the surface of unsteamed alder wood as well as steamed alder wood with a steam-air mixture at t = 95 °C and saturated steam at t = 115 °C darkened and browned due to photochemical reactions caused by UV radiation. The opposite tendency was recorded at the surface of alder wood steamed with saturated steam with a temperature of t = 135 °C, where the deep dark-brown-grey colour lightened to a brown-reddish colour shade under the influence of UV radiation. The analysis of the changes in the coordinates of the colour space CIE L*a*b* shows that the greater the darkening and browning of the alder wood by steaming, the smaller the changes in the values of ΔL*, Δa*, Δb* of the steamed alder wood caused by UV radiation. The positive effect of steaming on UV resistance is evidenced by the decrease in the overall colour difference ΔE*. While the value of the total colour difference of unsteamed alder wood caused by UV radiation is ΔE* = 10.9, it decreased to ΔE* = 8.7 for alder wood steamed with steam-air mixture at t = 95 °C, which is a decrease of 20.2 %; for alder wood steamed at t = 115 °C it decreased to ΔE* = 6.5, which is a decrease of 40.3 %; and for alder wood steamed with saturated water steam with the temperature t = 135 °C it decreased to ΔE* = 5.7, which is a decrease of 47.7 %.
{"title":"Colour Change of Steamed Alder Wood Caused by UV Radiation","authors":"L. Dzurenda, Michal Dudiak","doi":"10.5552/drvind.2022.0019","DOIUrl":"https://doi.org/10.5552/drvind.2022.0019","url":null,"abstract":"Alder wood (Alnus glutinosa L.) was steamed with a saturated steam-air mixture at a temperature of t = 95 °C, or saturated steam at t = 115 °C and t = 135 °C to obtain a pale brown colour, a light red-brown colour and a dark brown-grey colour. Subsequently, samples of unsteamed and steamed alder wood were irradiated with a UV lamp in a Xenotest Q-SUN Xe-3-HS after drying in order to test the colour stability of steamed alder wood. The colour change of the wood surface was evaluated by means of measured values on the coordinates of the colour space CIE L*a*b*. The results show that the surface of unsteamed alder wood as well as steamed alder wood with a steam-air mixture at t = 95 °C and saturated steam at t = 115 °C darkened and browned due to photochemical reactions caused by UV radiation. The opposite tendency was recorded at the surface of alder wood steamed with saturated steam with a temperature of t = 135 °C, where the deep dark-brown-grey colour lightened to a brown-reddish colour shade under the influence of UV radiation. The analysis of the changes in the coordinates of the colour space CIE L*a*b* shows that the greater the darkening and browning of the alder wood by steaming, the smaller the changes in the values of ΔL*, Δa*, Δb* of the steamed alder wood caused by UV radiation. The positive effect of steaming on UV resistance is evidenced by the decrease in the overall colour difference ΔE*. While the value of the total colour difference of unsteamed alder wood caused by UV radiation is ΔE* = 10.9, it decreased to ΔE* = 8.7 for alder wood steamed with steam-air mixture at t = 95 °C, which is a decrease of 20.2 %; for alder wood steamed at t = 115 °C it decreased to ΔE* = 6.5, which is a decrease of 40.3 %; and for alder wood steamed with saturated water steam with the temperature t = 135 °C it decreased to ΔE* = 5.7, which is a decrease of 47.7 %.","PeriodicalId":11427,"journal":{"name":"Drvna Industrija","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2022-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43066992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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