Xi Wu, C. A. Senalik, J. Wacker, Xiping Wang, Guanghui Li
This study describes assessment of the internal conditions of timber bridge structural members along Route 66 in California. These timber bridges were exposed to desert climate conditions for several decades, which can lead to a variety of deterioration. Overtime, the deterioration may cause loss of structural integrity within the bridges and lead to potentially hazardous conditions for the motoring public. Members from dismantled bridges were brought to the Forest Products Laboratory in Madison, WI. Strength-reducing features including decay, splits and cracks insect attack, and corrosion of metal components were initially identified using visual inspection. Further assessment was then performed using several nondestructive testing technologies including ground=penetrating radar (GPR). GPR was used, among other nondestructive techniques, to identify and locate internal features and defects within the timbers. The tomographic output of the GPR known as radargrams, revealed deterioration. Based on the information contained within the radargrams, it was possible to classify some internal features and defects with a high degree of certainty, whereas others remained less clear. In this study, the potential of using GPR for inspection of bridge timbers is discussed and supported through interpretation of the radargrams.
{"title":"Ground-Penetrating Radar Investigation of Salvaged Timber Girders from Bridges Along Route 66 in California","authors":"Xi Wu, C. A. Senalik, J. Wacker, Xiping Wang, Guanghui Li","doi":"10.22382/wfs-2020-007","DOIUrl":"https://doi.org/10.22382/wfs-2020-007","url":null,"abstract":"This study describes assessment of the internal conditions of timber bridge structural members along Route 66 in California. These timber bridges were exposed to desert climate conditions for several decades, which can lead to a variety of deterioration. Overtime, the deterioration may cause loss of structural integrity within the bridges and lead to potentially hazardous conditions for the motoring public. Members from dismantled bridges were brought to the Forest Products Laboratory in Madison, WI. Strength-reducing features including decay, splits and cracks insect attack, and corrosion of metal components were initially identified using visual inspection. Further assessment was then performed using several nondestructive testing technologies including ground=penetrating radar (GPR). GPR was used, among other nondestructive techniques, to identify and locate internal features and defects within the timbers. The tomographic output of the GPR known as radargrams, revealed deterioration. Based on the information contained within the radargrams, it was possible to classify some internal features and defects with a high degree of certainty, whereas others remained less clear. In this study, the potential of using GPR for inspection of bridge timbers is discussed and supported through interpretation of the radargrams.","PeriodicalId":23620,"journal":{"name":"Wood and Fiber Science","volume":"52 1","pages":"73-86"},"PeriodicalIF":1.4,"publicationDate":"2020-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41326623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Evaluating the wood properties of poplar clones to be used in fast-growing and high-yield plantation and select superior clones are critical to increase both quantity and quality of wood production. This study determined the fiber morphology, chemical composition and pulping of nine introduced poplar clones after six growing seasons and assessed their suitability for pulping and papermaking. Results showed that the fiber morphological differences among nine clones were not obvious. Fiber with length less than 1.0 mm accounted for 91.7% of the total fibers which were mainly short. Taro had longer and thinner fibers with the largest length-width ratio, followed by Bellatto , whereas Lambro owned the shortest and thickest fiber with a small length-width ratio. Neva had the Runkel ratio much high as 1.0, which was larger than that of other eight clones. From the point of view of chemical composition, Taro contained low content of ash, cold/hot water-soluble content, benzene ethanol-soluble content, and lignin, but higher content of holocellulose. 1% sodium hydroxide-soluble and pentosan contents were 20.47% and 22.62% respectively, on average; thus Taro can be suggested as good-quality industrial material applied in pulping and papermaking. On the contrary , Bellotto got imperfect overall performance, which was considered comprehensively before selection.
{"title":"Fiber Morphology, chemical composition, and pulping of nine introduced poplar clones grown in Beijing, China","authors":"Jingshan Ren, Jinhua Li, G. Nervo","doi":"10.22382/wfs-2020-011","DOIUrl":"https://doi.org/10.22382/wfs-2020-011","url":null,"abstract":"Evaluating the wood properties of poplar clones to be used in fast-growing and high-yield plantation and select superior clones are critical to increase both quantity and quality of wood production. This study determined the fiber morphology, chemical composition and pulping of nine introduced poplar clones after six growing seasons and assessed their suitability for pulping and papermaking. Results showed that the fiber morphological differences among nine clones were not obvious. Fiber with length less than 1.0 mm accounted for 91.7% of the total fibers which were mainly short. Taro had longer and thinner fibers with the largest length-width ratio, followed by Bellatto , whereas Lambro owned the shortest and thickest fiber with a small length-width ratio. Neva had the Runkel ratio much high as 1.0, which was larger than that of other eight clones. From the point of view of chemical composition, Taro contained low content of ash, cold/hot water-soluble content, benzene ethanol-soluble content, and lignin, but higher content of holocellulose. 1% sodium hydroxide-soluble and pentosan contents were 20.47% and 22.62% respectively, on average; thus Taro can be suggested as good-quality industrial material applied in pulping and papermaking. On the contrary , Bellotto got imperfect overall performance, which was considered comprehensively before selection.","PeriodicalId":23620,"journal":{"name":"Wood and Fiber Science","volume":"52 1","pages":"128-135"},"PeriodicalIF":1.4,"publicationDate":"2020-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48113653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Susanna Källbom, K. Lillqvist, S. Spoljaric, J. Seppälä, K. Segerholm, L. Rautkari, M. Hughes, M. Wålinder
The overall aim of this work was to gain more insight on the potential of modified wood (TMW) components for use in wood–thermoplastic composites (WPCs). Laboratory-scale TMWPCs were produced, and the effects of severe water soaking–drying cycles on the samples were studied. Water sorption behavior and resulting dimensional and micromorphological changes were also studied, and the results were compared with those of unmodified wood–plastic composites (UWPCs) used as control. The TMW was prepared by cutting a spruce board into half and subjecting one-half to an atmosphere of superheated steam at atmospheric pressure with a peak temperature of 210°C, with the other unmodified wood (UW) half as a control. The TMW and UW components were then prepared by a Wiley mill and thereafter sifted into smaller (mesh 0.20-0.40 mm) and larger (mesh 0.40-0.63 mm) size fractions. A portion of the wood components were also subjected to thermal extraction (HE). Composite samples with these different wood components, polypropylene (PP) matrix, and maleated PP (MAPP) as coupling agent (50/48/2 wood/PP/MAPP ratio by weight) were then prepared by using a Brabender mixer followed by hot pressing. The matching micromorphology of the composites before and after the soaking–drying cycles was analyzed using a surface preparation technique based on ultraviolet-laser ablation combined with scanning electron microscopy. The results of the water absorption tests showed, as hypothesized, a significantly reduced water absorption and resulting thickness swelling at the end of a soaking cycle for the TMWPCs compared with the controls (UWPCs). The water absorption was reduced with about 50-70% for TMWPC and 60-75% for HE-TMWPC. The thickness swelling for TMWPCs was reduced with about 40-70% compared with the controls. Similarly, the WPCs with HE-UW components absorbed about 20-45% less moisture and showed a reduced thickness swelling of about 25-40% compared with the controls. These observations also were in agreement with the micromorphology analysis of the composites before and after the moisture cycling which showed a more pronounced wood–plastic interfacial cracking (de-bonding) as well as other microstructure changes in the controls compared with those prepared with TMW and HE-UW components. Based on these observations, it is suggested that these potential bio-based building materials show increased potential durability for applications in harsh outdoor environments, in particular TMWPCs with a well-defined and comparably small size fractions of TMW components.
{"title":"Effects of water soaking-drying cycles on thermally modified spruce wood-plastic composites","authors":"Susanna Källbom, K. Lillqvist, S. Spoljaric, J. Seppälä, K. Segerholm, L. Rautkari, M. Hughes, M. Wålinder","doi":"10.22382/wfs-2020-002","DOIUrl":"https://doi.org/10.22382/wfs-2020-002","url":null,"abstract":"The overall aim of this work was to gain more insight on the potential of modified wood (TMW) components for use in wood–thermoplastic composites (WPCs). Laboratory-scale TMWPCs were produced, and the effects of severe water soaking–drying cycles on the samples were studied. Water sorption behavior and resulting dimensional and micromorphological changes were also studied, and the results were compared with those of unmodified wood–plastic composites (UWPCs) used as control. The TMW was prepared by cutting a spruce board into half and subjecting one-half to an atmosphere of superheated steam at atmospheric pressure with a peak temperature of 210°C, with the other unmodified wood (UW) half as a control. The TMW and UW components were then prepared by a Wiley mill and thereafter sifted into smaller (mesh 0.20-0.40 mm) and larger (mesh 0.40-0.63 mm) size fractions. A portion of the wood components were also subjected to thermal extraction (HE). Composite samples with these different wood components, polypropylene (PP) matrix, and maleated PP (MAPP) as coupling agent (50/48/2 wood/PP/MAPP ratio by weight) were then prepared by using a Brabender mixer followed by hot pressing. The matching micromorphology of the composites before and after the soaking–drying cycles was analyzed using a surface preparation technique based on ultraviolet-laser ablation combined with scanning electron microscopy. The results of the water absorption tests showed, as hypothesized, a significantly reduced water absorption and resulting thickness swelling at the end of a soaking cycle for the TMWPCs compared with the controls (UWPCs). The water absorption was reduced with about 50-70% for TMWPC and 60-75% for HE-TMWPC. The thickness swelling for TMWPCs was reduced with about 40-70% compared with the controls. Similarly, the WPCs with HE-UW components absorbed about 20-45% less moisture and showed a reduced thickness swelling of about 25-40% compared with the controls. These observations also were in agreement with the micromorphology analysis of the composites before and after the moisture cycling which showed a more pronounced wood–plastic interfacial cracking (de-bonding) as well as other microstructure changes in the controls compared with those prepared with TMW and HE-UW components. Based on these observations, it is suggested that these potential bio-based building materials show increased potential durability for applications in harsh outdoor environments, in particular TMWPCs with a well-defined and comparably small size fractions of TMW components.","PeriodicalId":23620,"journal":{"name":"Wood and Fiber Science","volume":"52 1","pages":"2-12"},"PeriodicalIF":1.4,"publicationDate":"2020-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46783576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Embedded waveguide technique is often not considered as a method for introducing ultrasonic wave for nondestructive testing (NDT). Because of the unique surface condition of wooden utility poles, the rough and uneven surface between the medium and the sensor introduces variation and signal attenuation, which impedes the use of a contact-based ultrasonic sensor. Many inspection and utility firms have adopted the use of inserting a small nail into the wooden pole for NDT. The mechanisms of excitation and reception of ultrasonic wave, however, are very different from the traditional contact-based mounting technique. Because very little research has been carried out on this methodology, this study focuses on the understanding of embedded waveguide excitation and reception in the time domain for wooden structure assessment in cylindrical symmetry. The resulted time domain waveform response is analyzed, and the associated findings will help infer important structural condition for NDT assessments. The study consists of numerical and empirical results to validate and understand the waveform characteristics and the associated energy modes that exist (Bodig 1982) in the two-dimensional wave propagation in a boundary medium
{"title":"A 2D Numerical Model of Ultrasonic Wave Propagation in Wooden Utility Poles Using Embedded Waveguide Excitation Technique","authors":"Lee Yishi, M. Mahoor, W. Hall","doi":"10.22382/wfs-2020-008","DOIUrl":"https://doi.org/10.22382/wfs-2020-008","url":null,"abstract":"Embedded waveguide technique is often not considered as a method for introducing ultrasonic wave for nondestructive testing (NDT). Because of the unique surface condition of wooden utility poles, the rough and uneven surface between the medium and the sensor introduces variation and signal attenuation, which impedes the use of a contact-based ultrasonic sensor. Many inspection and utility firms have adopted the use of inserting a small nail into the wooden pole for NDT. The mechanisms of excitation and reception of ultrasonic wave, however, are very different from the traditional contact-based mounting technique. Because very little research has been carried out on this methodology, this study focuses on the understanding of embedded waveguide excitation and reception in the time domain for wooden structure assessment in cylindrical symmetry. The resulted time domain waveform response is analyzed, and the associated findings will help infer important structural condition for NDT assessments. The study consists of numerical and empirical results to validate and understand the waveform characteristics and the associated energy modes that exist (Bodig 1982) in the two-dimensional wave propagation in a boundary medium","PeriodicalId":23620,"journal":{"name":"Wood and Fiber Science","volume":"52 1","pages":"87-101"},"PeriodicalIF":1.4,"publicationDate":"2020-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47757164","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rajendra Soti, Arijit Sinha, Ian Morrell, Byrne T. Miyamoto
The rocking behavior of self-centering mass plywood panel (MPP) walls was investigated with and without the use of supplementary energy dissipation systems. Two energy dissipation systems were tested. The first system used a kinematically expanding hysteretic damper (KE-HD), whereas the second system used slip friction connections (SFCs). The reviewed energy dissipating systems were used in a self-centering system comprising one unbonded posttensioned (PT) hold-down rod on each side of the MPP walls. The cyclic performance of the PT and the hybrid MPP specimens was investigated through a series of full-scale quasi-static cyclic tests. The test results demonstrated the viability of the investigated energy dissipaters in self-centering MPP rocking systems. Results further indicate that hybrid specimens with SFC dissipate more energy and provide higher strength than those with KE-HDs, however, with higher residual drift.
{"title":"Response of Self-Centering Mass Plywood Panel Shear Walls","authors":"Rajendra Soti, Arijit Sinha, Ian Morrell, Byrne T. Miyamoto","doi":"10.22382/wfs-2020-009","DOIUrl":"https://doi.org/10.22382/wfs-2020-009","url":null,"abstract":"The rocking behavior of self-centering mass plywood panel (MPP) walls was investigated with and without the use of supplementary energy dissipation systems. Two energy dissipation systems were tested. The first system used a kinematically expanding hysteretic damper (KE-HD), whereas the second system used slip friction connections (SFCs). The reviewed energy dissipating systems were used in a self-centering system comprising one unbonded posttensioned (PT) hold-down rod on each side of the MPP walls. The cyclic performance of the PT and the hybrid MPP specimens was investigated through a series of full-scale quasi-static cyclic tests. The test results demonstrated the viability of the investigated energy dissipaters in self-centering MPP rocking systems. Results further indicate that hybrid specimens with SFC dissipate more energy and provide higher strength than those with KE-HDs, however, with higher residual drift.","PeriodicalId":23620,"journal":{"name":"Wood and Fiber Science","volume":"52 1","pages":"102-116"},"PeriodicalIF":1.4,"publicationDate":"2020-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47713046","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. Kirker, C. Brischke, Leandro Passarini, S. Zelinka
Salt damage in wood can be recognized by its stringy appearance and is frequently observed in wood used in maritime structures and buildings built near the ocean. Whereas salt-damaged wood is common, little is known about the mechanism by which salt water alters the wood structure. There is no information on the effects of salt damage on the mechanical properties of wood. In this study, a laboratory method for creating salt damage in other porous materials was applied to wood. Wood pillars were placed in a reservoir of 5 M NaCl and exposed to a 40% RH environment. Capillary action pulled the salt water to the upper part of the pillars which were dry. Large deposits of effloresced salts were observed. The changes in mechanical properties caused by the salt were measured by the high-energy multiple impact (HEMI) test. Salt damage caused a reduction in the resistance to impact milling (RIM) of 6.5%, and it was concluded that salt damage causes only minor effects on the strength of wood. The tests were not conclusive as the exact mechanism of salt damage in treated wood. However, diffusion of mineral ions through the cell wall was found to be a key step in the salt damage mechanism.
木材的盐损害可以通过其粘连的外观来识别，并且经常在用于海洋结构和建造在海洋附近的建筑物的木材中观察到。虽然盐损伤木材很常见，但人们对盐水改变木材结构的机制知之甚少。目前还没有关于盐损害对木材机械性能影响的资料。在本研究中，一种在其他多孔材料中产生盐损伤的实验室方法应用于木材。木柱放置在5 M NaCl的储层中，暴露在40% RH的环境中。毛细管作用将盐水拉到干燥的柱子上部。观察到大量风化盐沉积。采用高能多次冲击(HEMI)试验测量了盐对材料力学性能的影响。盐损伤导致木材抗冲击铣削性能降低6.5%，表明盐损伤对木材强度的影响较小。这些试验并不能确定盐对处理过的木材造成损害的确切机制。然而，矿物离子通过细胞壁的扩散被发现是盐损伤机制的关键步骤。
{"title":"Salt Damage in Wood: Controlled Laboratory Exposures and Mechanical Property Measurements","authors":"G. Kirker, C. Brischke, Leandro Passarini, S. Zelinka","doi":"10.22382/wfs-2020-005","DOIUrl":"https://doi.org/10.22382/wfs-2020-005","url":null,"abstract":"Salt damage in wood can be recognized by its stringy appearance and is frequently observed in wood used in maritime structures and buildings built near the ocean. Whereas salt-damaged wood is common, little is known about the mechanism by which salt water alters the wood structure. There is no information on the effects of salt damage on the mechanical properties of wood. In this study, a laboratory method for creating salt damage in other porous materials was applied to wood. Wood pillars were placed in a reservoir of 5 M NaCl and exposed to a 40% RH environment. Capillary action pulled the salt water to the upper part of the pillars which were dry. Large deposits of effloresced salts were observed. The changes in mechanical properties caused by the salt were measured by the high-energy multiple impact (HEMI) test. Salt damage caused a reduction in the resistance to impact milling (RIM) of 6.5%, and it was concluded that salt damage causes only minor effects on the strength of wood. The tests were not conclusive as the exact mechanism of salt damage in treated wood. However, diffusion of mineral ions through the cell wall was found to be a key step in the salt damage mechanism.","PeriodicalId":23620,"journal":{"name":"Wood and Fiber Science","volume":"52 1","pages":"44-52"},"PeriodicalIF":1.4,"publicationDate":"2020-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45406235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Summary of awards presented at 2019 SWST Convention in Yosemite, California","authors":"S. Levan-Green","doi":"10.22382/wfs-2020-012","DOIUrl":"https://doi.org/10.22382/wfs-2020-012","url":null,"abstract":"","PeriodicalId":23620,"journal":{"name":"Wood and Fiber Science","volume":"52 1","pages":"136-137"},"PeriodicalIF":1.4,"publicationDate":"2020-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45229239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
W. Xu, Xiaoyang Fang, Jiatong Han, Zhihui Wu, Jilei Zhang
Effects of polyurethane (PU) coating thicknesses (0.15, 0.30, 0.45, and 0.60 mm) on sound absorption coefficients of four wood species were investigated using the standing wave ratio method with an input sound vibration frequency range set between 125 and 4000 Hz. Wood species of four specific gravity (SG) levels were Korean spruce, European spruce, Sitka spruce, and Picea brachytyla . Experimental results indicated that PU coating can significantly increase sound absorption coefficients of higher SG species such as Sitka spruce and Picea brachytyla in all tested frequency levels, but this significant increase was not observed in lower SG species such as Korean and European spruces when tested in the frequency range from 800 to 2000 Hz. Effects of coating thickness on sound absorption coefficients of four evaluated species were found to interact with wood SG values and input sound vibration frequency ranges. Specifically, coating 0.30-mm-thick PU on Korean and European spruces tends to result in significantly lower sound absorption coefficients among the ones coated with four evaluated thicknesses when tested at the frequency less than 800 Hz, but PU coating thickness resulting in lower sound absorption coefficients on Sitka spruce and Picea brachytyla was 0.15 mm. Sitka spruce and Picea brachytyla coated with 0.30- and 0.6-mm-thick PU had lower sound absorption coefficients when tested at the frequency ranging from 1000 to 2000 Hz. When tested at the frequency greater than 2500 Hz, sound absorption coefficients of four coated species increased as coating thickness increased from 0.30 to 0.60 mm with an increment of 0.15 mm, but these four species coated with three thicker PU had significantly lower sound absorption coefficients than the ones coated with 0.15-mm-thick PU. The uncoated higher SG species tended to have lower sound absorption coefficients than uncoated lower SG ones when tested in the frequency ranging from 500 to 4000 Hz, but the differences were not found when tested under the frequency less than 400 Hz. Coating four species with different thicknesses of PU could alter their SG effects on their sound absorption coefficients.
{"title":"Effect of Coating Thickness on Sound Absorption Property of Four Wood Species Commonly Used for Piano Soundboards","authors":"W. Xu, Xiaoyang Fang, Jiatong Han, Zhihui Wu, Jilei Zhang","doi":"10.22382/wfs-2020-004","DOIUrl":"https://doi.org/10.22382/wfs-2020-004","url":null,"abstract":"Effects of polyurethane (PU) coating thicknesses (0.15, 0.30, 0.45, and 0.60 mm) on sound absorption coefficients of four wood species were investigated using the standing wave ratio method with an input sound vibration frequency range set between 125 and 4000 Hz. Wood species of four specific gravity (SG) levels were Korean spruce, European spruce, Sitka spruce, and Picea brachytyla . Experimental results indicated that PU coating can significantly increase sound absorption coefficients of higher SG species such as Sitka spruce and Picea brachytyla in all tested frequency levels, but this significant increase was not observed in lower SG species such as Korean and European spruces when tested in the frequency range from 800 to 2000 Hz. Effects of coating thickness on sound absorption coefficients of four evaluated species were found to interact with wood SG values and input sound vibration frequency ranges. Specifically, coating 0.30-mm-thick PU on Korean and European spruces tends to result in significantly lower sound absorption coefficients among the ones coated with four evaluated thicknesses when tested at the frequency less than 800 Hz, but PU coating thickness resulting in lower sound absorption coefficients on Sitka spruce and Picea brachytyla was 0.15 mm. Sitka spruce and Picea brachytyla coated with 0.30- and 0.6-mm-thick PU had lower sound absorption coefficients when tested at the frequency ranging from 1000 to 2000 Hz. When tested at the frequency greater than 2500 Hz, sound absorption coefficients of four coated species increased as coating thickness increased from 0.30 to 0.60 mm with an increment of 0.15 mm, but these four species coated with three thicker PU had significantly lower sound absorption coefficients than the ones coated with 0.15-mm-thick PU. The uncoated higher SG species tended to have lower sound absorption coefficients than uncoated lower SG ones when tested in the frequency ranging from 500 to 4000 Hz, but the differences were not found when tested under the frequency less than 400 Hz. Coating four species with different thicknesses of PU could alter their SG effects on their sound absorption coefficients.","PeriodicalId":23620,"journal":{"name":"Wood and Fiber Science","volume":"52 1","pages":"28-43"},"PeriodicalIF":1.4,"publicationDate":"2020-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41406750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study is conducted on a raw material imported from several countries for the purpose of promoting the development of the world’s cotton spinning industry. If the time for selecting the raw material as well as the quality of the cotton spinning is improved, then time and money will be saved and the spinning industry will be improved. For this study, different cotton fibers were selected from different ecological regions. The cotton fibers were processed using the mercerization process, and then they were examined using X-ray diffraction (XRD), Fourier transform IR (FTIR) and scanning electronic microscope (SEM). High-volume instrument study was conducted to evaluate the physical properties of cotton fibers, including short fiber content, tensile strength, elongation at break, Micronaire value, and upper half mean length. In addition a change in fiber strength, the degree of crystallinity, and degree of orientation of cotton fibers before and after mercerization was also examined. SEM results show that the surface of cotton fibers became smooth and shiny after the treatment. FTIR and XRD revealed that the chemical composition did not change, but the degree of crystallinity decreased and the degree of orientation of alkalized cotton fibers increased after mercerization. In the second phase of this study, a correlation analysis was made between the physical properties of cotton fibers and the microstructural properties of alkalized cotton samples. This analysis revealed that the breaking strength of cotton fibers is strongly negatively correlated with the crystallinity of cotton fibers. The higher the tensile strength, the lower the crystallinity of cotton fibers, which leads to better mechanical properties of the end product. The degree of the orientation of cotton fibers is highly correlated with a tensile strength of cotton fibers. Xinjiang-Cn, BG-Au, and BG-Tu samples exhibited relatively better physical properties. BG-Au, BG-Tu, and Pakistan samples have higher values of tensile strength and lower values of yellowness; moreover, the raw material from these samples can be preferred according to correlation analysis. Correlation analysis between physical properties reveals that the tensile strength of cotton fibers is positively correlated with the Micronaire value; however, the correlation is not strong because of the lower value of the correlation coefficient as 0.4809.
{"title":"Influence of Cotton Fiber Properties on the Microstructural Characteristics of Mercerized Fibers by Regression Analysis","authors":"Hua Wang, A. Farooq, H. Memon","doi":"10.22382/wfs-2020-003","DOIUrl":"https://doi.org/10.22382/wfs-2020-003","url":null,"abstract":"This study is conducted on a raw material imported from several countries for the purpose of promoting the development of the world’s cotton spinning industry. If the time for selecting the raw material as well as the quality of the cotton spinning is improved, then time and money will be saved and the spinning industry will be improved. For this study, different cotton fibers were selected from different ecological regions. The cotton fibers were processed using the mercerization process, and then they were examined using X-ray diffraction (XRD), Fourier transform IR (FTIR) and scanning electronic microscope (SEM). High-volume instrument study was conducted to evaluate the physical properties of cotton fibers, including short fiber content, tensile strength, elongation at break, Micronaire value, and upper half mean length. In addition a change in fiber strength, the degree of crystallinity, and degree of orientation of cotton fibers before and after mercerization was also examined. SEM results show that the surface of cotton fibers became smooth and shiny after the treatment. FTIR and XRD revealed that the chemical composition did not change, but the degree of crystallinity decreased and the degree of orientation of alkalized cotton fibers increased after mercerization. In the second phase of this study, a correlation analysis was made between the physical properties of cotton fibers and the microstructural properties of alkalized cotton samples. This analysis revealed that the breaking strength of cotton fibers is strongly negatively correlated with the crystallinity of cotton fibers. The higher the tensile strength, the lower the crystallinity of cotton fibers, which leads to better mechanical properties of the end product. The degree of the orientation of cotton fibers is highly correlated with a tensile strength of cotton fibers. Xinjiang-Cn, BG-Au, and BG-Tu samples exhibited relatively better physical properties. BG-Au, BG-Tu, and Pakistan samples have higher values of tensile strength and lower values of yellowness; moreover, the raw material from these samples can be preferred according to correlation analysis. Correlation analysis between physical properties reveals that the tensile strength of cotton fibers is positively correlated with the Micronaire value; however, the correlation is not strong because of the lower value of the correlation coefficient as 0.4809.","PeriodicalId":23620,"journal":{"name":"Wood and Fiber Science","volume":"52 1","pages":"13-27"},"PeriodicalIF":1.4,"publicationDate":"2020-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41984223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
There are opportunities for improvement within the wood fiber supply chain. A significant amount of these opportunities are related to waste reduction. The body of literature focuses on what are the causes of waste and supply chain inefficiency. Conclusions suggest this is partially due to improper supply chain management and collaboration. There is a gap within the research regarding applications of lean tools in the wood fiber supply chain, especially tools that help suppliers and consumers work together to reduce waste. A value stream map (VSM) tool that focused on identifying lean waste in logistic operations was developed and applied. The VSM for the paper mill case study includes three processes: supplier, transportation to the wood yard, and receiving operations at the wood yard (consumer mill). Once the tool was applied, the following cost reductions were projected: the inbound logistics cost was reduced from $2.8 million to $2.3 million and the inventory carrying cost was reduced from $98,400 to $79,600 annually. The possible annual savings reported totaled $320,000 approximately by the introduction of lean principles that reduce the waste in transportation and carrying cost.
{"title":"A Lean Logistics Framework: A Case Study in the Wood Fiber Supply Chain","authors":"Paula Daniela Fallas, Henry Quesada, B. Bond","doi":"10.22382/wfs-2020-010","DOIUrl":"https://doi.org/10.22382/wfs-2020-010","url":null,"abstract":"There are opportunities for improvement within the wood fiber supply chain. A significant amount of these opportunities are related to waste reduction. The body of literature focuses on what are the causes of waste and supply chain inefficiency. Conclusions suggest this is partially due to improper supply chain management and collaboration. There is a gap within the research regarding applications of lean tools in the wood fiber supply chain, especially tools that help suppliers and consumers work together to reduce waste. A value stream map (VSM) tool that focused on identifying lean waste in logistic operations was developed and applied. The VSM for the paper mill case study includes three processes: supplier, transportation to the wood yard, and receiving operations at the wood yard (consumer mill). Once the tool was applied, the following cost reductions were projected: the inbound logistics cost was reduced from $2.8 million to $2.3 million and the inventory carrying cost was reduced from $98,400 to $79,600 annually. The possible annual savings reported totaled $320,000 approximately by the introduction of lean principles that reduce the waste in transportation and carrying cost.","PeriodicalId":23620,"journal":{"name":"Wood and Fiber Science","volume":"52 1","pages":"117-127"},"PeriodicalIF":1.4,"publicationDate":"2020-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43168565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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