Meihua Xie, Ping Zhang, Yangbing Jin, Zhe Wang, C. Jin
Abstract Interfacial solar-driven steam generation is one of the most promising techniques used to produce clean water. However, achieving rapid water evaporation using solar steam generation devices is challenging because of their two-dimensional (2D) planar structures and confined evaporation areas. The three-dimensional (3D) structural design of evaporation devices improves water evaporation rates, thereby enhancing solar-driven steam generation. This study developed a 3D wood-based evaporator through 3D structure shaping and the flexible treatment of wood that involved coating photothermal materials with tannic acid. Because of the ampliative evaporation area and outstanding absorption, the water evaporation rate of the prepared 3D wood-based evaporator was as high as 2.5 kg m−2 h−1, and the efficiency of energy transformation was up to 101 % under simulated 1-sun irradiation; the evaporation rate and efficiency of energy transformation were considerably higher than those of 2D planar wood evaporators. Furthermore, the effective seawater desalination performance and good durability of the 3D wood-based evaporator were demonstrated. This study provides different insights into the fabrication of high-efficiency wood-based solar steam generators with high prospects for application in seawater desalination.
{"title":"3D wood-based evaporator for highly efficient solar steam generation","authors":"Meihua Xie, Ping Zhang, Yangbing Jin, Zhe Wang, C. Jin","doi":"10.1515/hf-2022-0185","DOIUrl":"https://doi.org/10.1515/hf-2022-0185","url":null,"abstract":"Abstract Interfacial solar-driven steam generation is one of the most promising techniques used to produce clean water. However, achieving rapid water evaporation using solar steam generation devices is challenging because of their two-dimensional (2D) planar structures and confined evaporation areas. The three-dimensional (3D) structural design of evaporation devices improves water evaporation rates, thereby enhancing solar-driven steam generation. This study developed a 3D wood-based evaporator through 3D structure shaping and the flexible treatment of wood that involved coating photothermal materials with tannic acid. Because of the ampliative evaporation area and outstanding absorption, the water evaporation rate of the prepared 3D wood-based evaporator was as high as 2.5 kg m−2 h−1, and the efficiency of energy transformation was up to 101 % under simulated 1-sun irradiation; the evaporation rate and efficiency of energy transformation were considerably higher than those of 2D planar wood evaporators. Furthermore, the effective seawater desalination performance and good durability of the 3D wood-based evaporator were demonstrated. This study provides different insights into the fabrication of high-efficiency wood-based solar steam generators with high prospects for application in seawater desalination.","PeriodicalId":13083,"journal":{"name":"Holzforschung","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45513018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Roberta Dagher, Tatjana Stevanovic, Véronic Landry
Wood is a biosourced material with unique aesthetic features due to its anatomy and chemical composition. White oak wood surface color can be modified with the use of iron salts, which react with wood phenolic extractives, present as free molecules in wood porous structure. The impact of modifying wood surface color with iron salts on the final appearance of wood, including its color, grain contrast and surface roughness, was evaluated in this study. Results showed that following the application of iron (III) sulphate aqueous solutions on white oak wood surface, its roughness increased, which is due to grain raising after wetting of wood surface. The color modification of wood surface with iron (III) sulphate aqueous solutions was compared with a non-reactive water based blue stain. The contrast associated to wood grain that was expressed by the standard deviation of luminance values in wood images, also increased after application of the iron (III) sulphate aqueous solution on white oak wood surface. The comparison of contrast changes showed that wood samples stained with iron (III) sulphate on their curved surface had the highest increase in grain contrast compared to iron-stained wood showing the straight grain and to wood surfaces colored by a non-reactive water-based stain for both curved and straight grains.
{"title":"Wood color modification with iron salts aqueous solutions: effect on wood grain contrast and surface roughness.","authors":"Roberta Dagher, Tatjana Stevanovic, Véronic Landry","doi":"10.1515/hf-2022-0189","DOIUrl":"https://doi.org/10.1515/hf-2022-0189","url":null,"abstract":"<p><p>Wood is a biosourced material with unique aesthetic features due to its anatomy and chemical composition. White oak wood surface color can be modified with the use of iron salts, which react with wood phenolic extractives, present as free molecules in wood porous structure. The impact of modifying wood surface color with iron salts on the final appearance of wood, including its color, grain contrast and surface roughness, was evaluated in this study. Results showed that following the application of iron (III) sulphate aqueous solutions on white oak wood surface, its roughness increased, which is due to grain raising after wetting of wood surface. The color modification of wood surface with iron (III) sulphate aqueous solutions was compared with a non-reactive water based blue stain. The contrast associated to wood grain that was expressed by the standard deviation of luminance values in wood images, also increased after application of the iron (III) sulphate aqueous solution on white oak wood surface. The comparison of contrast changes showed that wood samples stained with iron (III) sulphate on their curved surface had the highest increase in grain contrast compared to iron-stained wood showing the straight grain and to wood surfaces colored by a non-reactive water-based stain for both curved and straight grains.</p>","PeriodicalId":13083,"journal":{"name":"Holzforschung","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10214018/pdf/hfsg-77-5-hf-2022-0189.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9545788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jing Li, Haocheng Xu, Ying Zhang, Tuhua Zhong, Katherine Semple, V. Nasir, Hankun Wang, C. Dai
Abstract Variation in anatomical features of the culm wall namely the shape and size distributions of vascular bundles between different genera and species of bamboo is not well understood due to the cumbersome task of manual measurements. Using machine learning methodology, this work presents a universal vascular bundle detection model for rapid, reliable, and automatic characterization of vascular bundles in culm cross sections of 213 species across 23 genera of Chinese bamboos. The number of vascular bundles and the fiber sheath area have positive linear correlations with the outer circumference and the wall thickness, respectively. The distribution density of vascular bundles has a decay exponential correlation with the outer circumference and the wall thickness. The average fiber volume fraction was 35.2 % ± 7 % with relatively small variation between species. Bamboo species could be grouped into three categories based the endodermis to epidermis distribution pattern of radial and tangential length of vascular bundles, two categories of radial-to-tangential ratio and four categories of fiber sheath area distribution pattern. Implications on bamboo classification, structural and pulp/paper applications were discussed. The findings from this study provide groundwork for the establishment of a unified, authoritative and objective bamboo classification system based on the vascular tissue morphology.
{"title":"Radial distribution of vascular bundle morphology in Chinese bamboos: machine learning methodology for rapid sampling and classification","authors":"Jing Li, Haocheng Xu, Ying Zhang, Tuhua Zhong, Katherine Semple, V. Nasir, Hankun Wang, C. Dai","doi":"10.1515/hf-2022-0165","DOIUrl":"https://doi.org/10.1515/hf-2022-0165","url":null,"abstract":"Abstract Variation in anatomical features of the culm wall namely the shape and size distributions of vascular bundles between different genera and species of bamboo is not well understood due to the cumbersome task of manual measurements. Using machine learning methodology, this work presents a universal vascular bundle detection model for rapid, reliable, and automatic characterization of vascular bundles in culm cross sections of 213 species across 23 genera of Chinese bamboos. The number of vascular bundles and the fiber sheath area have positive linear correlations with the outer circumference and the wall thickness, respectively. The distribution density of vascular bundles has a decay exponential correlation with the outer circumference and the wall thickness. The average fiber volume fraction was 35.2 % ± 7 % with relatively small variation between species. Bamboo species could be grouped into three categories based the endodermis to epidermis distribution pattern of radial and tangential length of vascular bundles, two categories of radial-to-tangential ratio and four categories of fiber sheath area distribution pattern. Implications on bamboo classification, structural and pulp/paper applications were discussed. The findings from this study provide groundwork for the establishment of a unified, authoritative and objective bamboo classification system based on the vascular tissue morphology.","PeriodicalId":13083,"journal":{"name":"Holzforschung","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45012137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
N. Terashima, Y. Matsushita, Sachie Yagami, H. Nishimura, Masato Yoshida, K. Fukushima
Abstract The physical, chemical and biological properties of wood depend on the supramolecular assembly of cellulose microfibrils (CMFs), hemicelluloses (HCs) and lignin in the growing cell walls. Based on the 13C-tracer studies of ginkgo xylem formation, a hypothetical scenario for the role of monolignol glucosides (MLGs) in the assembly is proposed as follows: (1) Both moieties, aglycone monolignols and glycone d-glucose (d-Glc), play essential roles in a cooperative manner in delivery of hydrophobic and highly reactive p-hydroxycinnamyl- (H), coniferyl- (G) alcohols to the hydrophilic site of lignin deposition. (2) The d-Glc liberated at lignification site is converted into essential HCs mainly via Golgi apparatus under the influence of diurnally changing turgor pressure, and partly converted in the apoplast. (3) At cell corner middle lamella, a pressure-resistant layer of HG-lignin-HCs-CMFs is formed, and allows expansion of new cells in cambium region by elevation of turgor pressure. The deformable G-lignin-HCs-CMFs layer at secondary wall shrinks by dehydration of the swollen gel of HCs-CMFs during differentiation, and contributes posture control of standing tree. On-demand quick supply of a large amount of monolignols and HCs can be achieved by the large storage and delivery of MLGs in the growing ginkgo xylem.
木材的物理、化学和生物学特性取决于生长细胞壁中纤维素微原纤维(CMFs)、半纤维素(hc)和木质素的超分子组装。基于银杏木质部形成的13c示踪研究，提出了单脂醇糖苷(MLGs)在木质素组装中的作用假设:(1)糖醛基单脂醇和糖醛基d-葡萄糖(d-Glc)这两个部分在将疏水和高活性的对羟基肉桂基- (H)、针叶树基- (G)醇传递到木质素沉积的亲水性位点中发挥重要作用。(2)木质化部位释放的d-Glc在日变化的膨胀压力影响下主要通过高尔基体转化为必需的hc，部分在外质体中转化。(3)在细胞角的中间片层，形成了一层hg -木质素- hc - cmfs耐压层，并通过膨胀压力的升高使形成层区域的新细胞膨胀。次级壁上可变形的g -木质素-HCs-CMFs层在分化过程中因HCs-CMFs肿胀凝胶脱水而收缩，对立木姿态控制起作用。在生长中的银杏木质部中，MLGs的大量储存和输送可以实现大量单素醇和hc的按需快速供应。
{"title":"Role of monolignol glucosides in supramolecular assembly of cell wall components in ginkgo xylem formation","authors":"N. Terashima, Y. Matsushita, Sachie Yagami, H. Nishimura, Masato Yoshida, K. Fukushima","doi":"10.1515/hf-2022-0163","DOIUrl":"https://doi.org/10.1515/hf-2022-0163","url":null,"abstract":"Abstract The physical, chemical and biological properties of wood depend on the supramolecular assembly of cellulose microfibrils (CMFs), hemicelluloses (HCs) and lignin in the growing cell walls. Based on the 13C-tracer studies of ginkgo xylem formation, a hypothetical scenario for the role of monolignol glucosides (MLGs) in the assembly is proposed as follows: (1) Both moieties, aglycone monolignols and glycone d-glucose (d-Glc), play essential roles in a cooperative manner in delivery of hydrophobic and highly reactive p-hydroxycinnamyl- (H), coniferyl- (G) alcohols to the hydrophilic site of lignin deposition. (2) The d-Glc liberated at lignification site is converted into essential HCs mainly via Golgi apparatus under the influence of diurnally changing turgor pressure, and partly converted in the apoplast. (3) At cell corner middle lamella, a pressure-resistant layer of HG-lignin-HCs-CMFs is formed, and allows expansion of new cells in cambium region by elevation of turgor pressure. The deformable G-lignin-HCs-CMFs layer at secondary wall shrinks by dehydration of the swollen gel of HCs-CMFs during differentiation, and contributes posture control of standing tree. On-demand quick supply of a large amount of monolignols and HCs can be achieved by the large storage and delivery of MLGs in the growing ginkgo xylem.","PeriodicalId":13083,"journal":{"name":"Holzforschung","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45963787","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The incorporation of nano-particles into coatings to protect wood against UV light has tremendous potential for improving coating performance. However, the understanding of the mechanisms by which these particles function on wood surfaces remains limited. The distribution and potential chemical interactions between alpha Fe2O3 and wood were studied. The ability of different sizes of Fe2O3 particles to intercept various wavelengths of light was assessed using ultraviolet/visible (UV–vis) spectroscopy using TiO2 and ZnO particles for comparison. All particles intercepted UV light, but α-Fe2O3 also intercepted a portion of the visible spectrum which might help explain its better performance. Scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM-EDS) analysis of α-Fe2O3 nano-particle distribution on different wood orientations of radiata pine (Pinus radiata D. Don) and shining gum (Eucalyptus nitens) showed that iron particles were uniformly distributed on both pine and shining gum, but provided better UV protection to the more permeable radiata pine surfaces. Characterization of chemical interactions between α-Fe2O3 and isolated lignin and cellulose by Fourier Transform Infrared Spectroscopy (FTIR) suggested substantial interactions between these particles and lignin components, but little interaction with cellulose. The results suggest that the role of nano-particles in the UV protection of wood surface is to intercept and disperse the light energy while interacting with the wood.
{"title":"Role of α-Fe2O3 nano-particles in protecting wood from ultraviolet light degradation","authors":"Tengfei Yi, J. Morrell","doi":"10.1515/hf-2023-0001","DOIUrl":"https://doi.org/10.1515/hf-2023-0001","url":null,"abstract":"Abstract The incorporation of nano-particles into coatings to protect wood against UV light has tremendous potential for improving coating performance. However, the understanding of the mechanisms by which these particles function on wood surfaces remains limited. The distribution and potential chemical interactions between alpha Fe2O3 and wood were studied. The ability of different sizes of Fe2O3 particles to intercept various wavelengths of light was assessed using ultraviolet/visible (UV–vis) spectroscopy using TiO2 and ZnO particles for comparison. All particles intercepted UV light, but α-Fe2O3 also intercepted a portion of the visible spectrum which might help explain its better performance. Scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM-EDS) analysis of α-Fe2O3 nano-particle distribution on different wood orientations of radiata pine (Pinus radiata D. Don) and shining gum (Eucalyptus nitens) showed that iron particles were uniformly distributed on both pine and shining gum, but provided better UV protection to the more permeable radiata pine surfaces. Characterization of chemical interactions between α-Fe2O3 and isolated lignin and cellulose by Fourier Transform Infrared Spectroscopy (FTIR) suggested substantial interactions between these particles and lignin components, but little interaction with cellulose. The results suggest that the role of nano-particles in the UV protection of wood surface is to intercept and disperse the light energy while interacting with the wood.","PeriodicalId":13083,"journal":{"name":"Holzforschung","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49133651","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Poor dimensional stability restricts the commercial utilization of fast-growing wood. In this study, fast-growing poplar (Populus cathayana) was treated by removing hemicellulose with hydrothermal treatment and impregnating alkali lignin via full-cell process, synergistically, for enhanced dimensional stability. After modification, hydroxyl groups were reduced in hemicellulose removed wood (DHC), alkali lignin was observed to fill in the cell lumens of vessels and wood fibers in the impregnated wood (AL) and in the wood modified by hemicellulose removal with alkali lignin impregnation (DHCAL). Compared with untreated wood, the volumetric swelling ratio of DHC and AL decreased by 11 % and 21 % under relative humidity (RH) of 89 %, respectively. The volumetric swelling ratio of DHCAL decreased by over 50 %, indicating a positive synergistic effect. The combination of hemicellulose removal and alkali lignin impregnation treatment improved the dimensional stability of wood significantly by reconstructing wood chemical components with various levels of hygroscopicity. This work could meaningfully contribute to the efficient utilization of fast-growing wood and promote the added value of industrial alkali lignin.
{"title":"Synergistic improvement to dimensional stability of Populus cathay ana via hemicellulose removal/alkali lignin impregnation","authors":"Meng Yang, Runhua Zhang, E. Ma","doi":"10.1515/hf-2022-0147","DOIUrl":"https://doi.org/10.1515/hf-2022-0147","url":null,"abstract":"Abstract Poor dimensional stability restricts the commercial utilization of fast-growing wood. In this study, fast-growing poplar (Populus cathayana) was treated by removing hemicellulose with hydrothermal treatment and impregnating alkali lignin via full-cell process, synergistically, for enhanced dimensional stability. After modification, hydroxyl groups were reduced in hemicellulose removed wood (DHC), alkali lignin was observed to fill in the cell lumens of vessels and wood fibers in the impregnated wood (AL) and in the wood modified by hemicellulose removal with alkali lignin impregnation (DHCAL). Compared with untreated wood, the volumetric swelling ratio of DHC and AL decreased by 11 % and 21 % under relative humidity (RH) of 89 %, respectively. The volumetric swelling ratio of DHCAL decreased by over 50 %, indicating a positive synergistic effect. The combination of hemicellulose removal and alkali lignin impregnation treatment improved the dimensional stability of wood significantly by reconstructing wood chemical components with various levels of hygroscopicity. This work could meaningfully contribute to the efficient utilization of fast-growing wood and promote the added value of industrial alkali lignin.","PeriodicalId":13083,"journal":{"name":"Holzforschung","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44626476","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract In this study, representative lignin samples differing in hydroxyl content, molecular weight, linkage composition and lignin units ratio were prepared from eucalyptus wood by different isolation means and modification means: milled wood lignin (MWL), kraft lignin classified at different pH (KL), lignocresol (LC), lignoresorcinol (LR), lignopyrogallol (LP) as well as lignocresol secondary functional switched samples (LC 2ndderiv). The structure of various lignins was characterized in detail by Fourier transform infrared (FT-IR) spectroscopy, gel permeation chromatography (GPC) and nuclear magnetic resonance (NMR). In order to eliminate the interference of other factors, bovine serum albumin (BSA) with relatively simple protein structure and different kinds of lignin and their derivatives were selected as the research objects. The adsorption/desorption behavior and mechanism between lignin samples and BSA were studied by quartz crystal microbalance with dissipation monitoring (QCM-D). The results showed that the content of phenolic hydroxyl was the main factor affecting the interaction of lignin and BSA, but in addition, the molecular size, linkages composition and the types of lignin units also had important effects on its adsorption behavior. The research will provide theoretical guidance and all-round reliable basic data for the interaction of lignin on lignocellulose hydrolysis enzymes in industrial application.
{"title":"Structural comparison of different isolated eucalyptus lignins and analysis of their interaction mechanism with bovine serum albumin solution under QCM-D","authors":"Haonan Zhang, Qi Liu, Yanchen Zhu, Zhang Feng, Hao Ren, H. Zhai","doi":"10.1515/hf-2022-0170","DOIUrl":"https://doi.org/10.1515/hf-2022-0170","url":null,"abstract":"Abstract In this study, representative lignin samples differing in hydroxyl content, molecular weight, linkage composition and lignin units ratio were prepared from eucalyptus wood by different isolation means and modification means: milled wood lignin (MWL), kraft lignin classified at different pH (KL), lignocresol (LC), lignoresorcinol (LR), lignopyrogallol (LP) as well as lignocresol secondary functional switched samples (LC 2ndderiv). The structure of various lignins was characterized in detail by Fourier transform infrared (FT-IR) spectroscopy, gel permeation chromatography (GPC) and nuclear magnetic resonance (NMR). In order to eliminate the interference of other factors, bovine serum albumin (BSA) with relatively simple protein structure and different kinds of lignin and their derivatives were selected as the research objects. The adsorption/desorption behavior and mechanism between lignin samples and BSA were studied by quartz crystal microbalance with dissipation monitoring (QCM-D). The results showed that the content of phenolic hydroxyl was the main factor affecting the interaction of lignin and BSA, but in addition, the molecular size, linkages composition and the types of lignin units also had important effects on its adsorption behavior. The research will provide theoretical guidance and all-round reliable basic data for the interaction of lignin on lignocellulose hydrolysis enzymes in industrial application.","PeriodicalId":13083,"journal":{"name":"Holzforschung","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48669656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Degradation of the mechanical properties of heat-treated wood is a significant problem that needs to be addressed. This study aimed to stabilize the mechanical strength of heat-treated spruce wood by adding gaseous ammonia during the heat treatment. Gaseous ammonia penetrates rapidly into wood and is expected to form ammonium hydroxide when combined with water in the wood. This modification strategy neutralizes the acids produced by the degradation of hemicelluloses and reduces the degradation of the wood polymer composition and cell-wall structure. The preservation of wood polymer composition and cell-wall structure increases the indentation modulus of the wood cell walls. This increases the strength of the wood cell walls, resulting in an improvement in the mechanical properties of the heat-treated wood. The heat-treated wood’s dimensional stability and equilibrium moisture content are only slightly affected by the weak alkalinity modification.
{"title":"Adding gaseous ammonia with heat treatment to improve the mechanical properties of spruce wood","authors":"Yiqin Gao, Li Li, Yao Chen","doi":"10.1515/hf-2022-0179","DOIUrl":"https://doi.org/10.1515/hf-2022-0179","url":null,"abstract":"Abstract Degradation of the mechanical properties of heat-treated wood is a significant problem that needs to be addressed. This study aimed to stabilize the mechanical strength of heat-treated spruce wood by adding gaseous ammonia during the heat treatment. Gaseous ammonia penetrates rapidly into wood and is expected to form ammonium hydroxide when combined with water in the wood. This modification strategy neutralizes the acids produced by the degradation of hemicelluloses and reduces the degradation of the wood polymer composition and cell-wall structure. The preservation of wood polymer composition and cell-wall structure increases the indentation modulus of the wood cell walls. This increases the strength of the wood cell walls, resulting in an improvement in the mechanical properties of the heat-treated wood. The heat-treated wood’s dimensional stability and equilibrium moisture content are only slightly affected by the weak alkalinity modification.","PeriodicalId":13083,"journal":{"name":"Holzforschung","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41912323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lipeng Zhang, Qifang Xie, Yajie Wu, Baozhuang Zhang, Ningfen Su
Abstract Wood is mainly subjected to transverse compression in many critical parts of Chinese traditional timber structures, e.g. the mortise-tenon and Dou-Gong joints. Seismic is one of the dynamic actions faced by these structures and will cause wood to suffer higher loading speeds than quasi-static loads. The investigation of the seismic strain rates (SSRs) effects of wood under perpendicular-to-grain compression (PTGc) is important. One hundred and forty-four radial small clear wood specimens were prepared using Dahurian larch, Mongolian pine and Chinese poplar. Monotonic and cyclic compression tests were conducted under three SSRs (10−3 s−1, 10−2 s−1, and 10−1 s−1) and the quasi-static strain rate (10−4 s−1). Failure modes, stress-strain curves, yield strengths, elastic moduli and the unloading/reloading moduli were analyzed. Results indicated that the PTGc properties were highly sensitive to SSRs under both the monotonic and cyclic compression. Strengths showed higher sensitivity to SSRs than elastic moduli. The SSRs effects of wood under cyclic compression have greater variability than the monotonic counterparts. The unloading/reloading moduli shows little SSR effects statistically. Comparisons were made between the existing PTG and the parallel-to-grain test results and a fitted general expression was obtained. Furthermore, an SSR-dependent stress-strain model was proposed and verified by tests.
{"title":"Effects of seismic strain rates on the perpendicular-to-grain compression behaviour of Dahurian larch, Mongolian pine and Chinese poplar: tests and stress-strain model","authors":"Lipeng Zhang, Qifang Xie, Yajie Wu, Baozhuang Zhang, Ningfen Su","doi":"10.1515/hf-2022-0135","DOIUrl":"https://doi.org/10.1515/hf-2022-0135","url":null,"abstract":"Abstract Wood is mainly subjected to transverse compression in many critical parts of Chinese traditional timber structures, e.g. the mortise-tenon and Dou-Gong joints. Seismic is one of the dynamic actions faced by these structures and will cause wood to suffer higher loading speeds than quasi-static loads. The investigation of the seismic strain rates (SSRs) effects of wood under perpendicular-to-grain compression (PTGc) is important. One hundred and forty-four radial small clear wood specimens were prepared using Dahurian larch, Mongolian pine and Chinese poplar. Monotonic and cyclic compression tests were conducted under three SSRs (10−3 s−1, 10−2 s−1, and 10−1 s−1) and the quasi-static strain rate (10−4 s−1). Failure modes, stress-strain curves, yield strengths, elastic moduli and the unloading/reloading moduli were analyzed. Results indicated that the PTGc properties were highly sensitive to SSRs under both the monotonic and cyclic compression. Strengths showed higher sensitivity to SSRs than elastic moduli. The SSRs effects of wood under cyclic compression have greater variability than the monotonic counterparts. The unloading/reloading moduli shows little SSR effects statistically. Comparisons were made between the existing PTG and the parallel-to-grain test results and a fitted general expression was obtained. Furthermore, an SSR-dependent stress-strain model was proposed and verified by tests.","PeriodicalId":13083,"journal":{"name":"Holzforschung","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47817343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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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