This study aimed at the production of reinforced polymer composites from coconut fibers and plastics. Coir Fiber (CF) sheets with dimensions of 200 x 200 x 12 mm ( + 3mm) were used as the natural fiber, whereas a thermosetting plastic or an elastomer (unsaturated polyester [UPE] or silicon rubber [SIR]) was used as the binder in the matrix. Processing was performed using the vacuum infiltration method, wherein the liquid polymer was made to infiltrate the cellulose of the natural structure of the CFs and disperse within the CF matrix. The effect of production variables on thermal, sound, and flexural properties was evaluated. Material characterization tests revealed that the addition of the UPE and SIR as reinforcing materials enhanced the thermal conductivity of the CFs. UPE improved the modulus of rupture of the CFs. The study further revealed that CF/SIR composites showed high ductility. Analysis of the sound absorption properties of the composites revealed that the noise reduction coefficient (NRC) of the CF/400 wt% SIR composite was the highest. Moreover, the CF/SIR composites showed higher sound absorption efficiency (α) values at high frequencies than those of the CF/UPE composites. However, the polymers had no effect on the NRC of the neat CFs when added in a low concentration (200 wt%). This study shows that coconut husk waste can be used to produce reinforced polymer composites with desirable thermal conductivity and sound absorption characteristics.
本研究旨在用椰子纤维和塑料生产增强聚合物复合材料。尺寸为200 x 200 x 12 mm（+3mm）的Coir纤维（CF）片材被用作天然纤维，而热固性塑料或弹性体（不饱和聚酯[UPE]或硅橡胶[SIR]）被用作基质中的粘合剂。使用真空渗透法进行处理，其中使液体聚合物渗透CF的天然结构的纤维素并分散在CF基质内。评估了生产变量对热性能、声音性能和弯曲性能的影响。材料表征测试表明，UPE和SIR作为增强材料的加入提高了CF的热导率。UPE提高了CF的断裂模量。研究进一步表明，CF/SIR复合材料具有较高的延展性。对复合材料的吸声性能分析表明，CF/400wt%SIR复合材料的降噪系数（NRC）最高。此外，与CF/UPE复合材料相比，CF/SIR复合材料在高频下表现出更高的吸声效率（α）值。然而，当以低浓度（200wt%）添加时，聚合物对纯CF的NRC没有影响。该研究表明，椰子壳废料可用于生产具有理想导热性和吸声特性的增强聚合物复合材料。
{"title":"Properties of Reinforced Polymer Composite Produced from Coconut Fiber","authors":"W. Cheewawuttipong, A. Memon","doi":"10.22382/WFS-2021-15","DOIUrl":"https://doi.org/10.22382/WFS-2021-15","url":null,"abstract":"This study aimed at the production of reinforced polymer composites from coconut fibers and plastics. Coir Fiber (CF) sheets with dimensions of 200 x 200 x 12 mm ( + 3mm) were used as the natural fiber, whereas a thermosetting plastic or an elastomer (unsaturated polyester [UPE] or silicon rubber [SIR]) was used as the binder in the matrix. Processing was performed using the vacuum infiltration method, wherein the liquid polymer was made to infiltrate the cellulose of the natural structure of the CFs and disperse within the CF matrix. The effect of production variables on thermal, sound, and flexural properties was evaluated. Material characterization tests revealed that the addition of the UPE and SIR as reinforcing materials enhanced the thermal conductivity of the CFs. UPE improved the modulus of rupture of the CFs. The study further revealed that CF/SIR composites showed high ductility. Analysis of the sound absorption properties of the composites revealed that the noise reduction coefficient (NRC) of the CF/400 wt% SIR composite was the highest. Moreover, the CF/SIR composites showed higher sound absorption efficiency (α) values at high frequencies than those of the CF/UPE composites. However, the polymers had no effect on the NRC of the neat CFs when added in a low concentration (200 wt%). This study shows that coconut husk waste can be used to produce reinforced polymer composites with desirable thermal conductivity and sound absorption characteristics.","PeriodicalId":23620,"journal":{"name":"Wood and Fiber Science","volume":"53 1","pages":"147-156"},"PeriodicalIF":1.4,"publicationDate":"2021-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41525991","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}
Fenglu Liu, Houjiang Zhang, Xiping Wang, F. Jiang, Wenhua Yu, R. Ross
The objective of this study was to investigate the effects of tree diameter and juvenile wood on acoustic wave propagation in standing trees. Two-layer tree models with various diameters and proportions of juvenile wood were constructed to examine the effects of these two factors on propagation patterns and velocity of acoustic waves. The simulation results and analysis indicated that acoustic wave propagation in trees is dependent on both tree diameter and propagation distance. In the context of time-of-flight (TOF) acoustic measurement on standing trees with a test span of 1.2 m, when tree diameter is 10 cm or less, or slenderness is twelve or greater, wave propagates as quasi-plane waves in tree trunk, and the tree velocity determined using the TOF method is then comparable to the log velocity measured using the acoustic resonance method. When tree diameter is 40 cm or larger, or slenderness is three or less, wave propagates as dilatational waves in the tree trunk; thus, the three-dimensional wave equation should be considered for wood property prediction. When tree diameter falls between 10 and 40 cm or slenderness falls between 3 and 12, wave propagation is in a transitional phase. Mathematical models were developed to convert the tree velocity in the transition mode to the resonance velocity. It was found that juvenile wood content resulted in a 113-m/s reduction in acoustic velocity. In addition, our analysis indicated that wave propagation in standing trees is controlled by the wood properties of entire cross section, not just the outerwood. Therefore, the wave velocity measured on standing trees reflects the global properties of the wood between the two measuring points.
{"title":"Acoustic Wave Propagation in Standing Trees - Part II. Effects of Tree Diamter and Juvenile Wood","authors":"Fenglu Liu, Houjiang Zhang, Xiping Wang, F. Jiang, Wenhua Yu, R. Ross","doi":"10.22382/WFS-2021-12","DOIUrl":"https://doi.org/10.22382/WFS-2021-12","url":null,"abstract":"The objective of this study was to investigate the effects of tree diameter and juvenile wood on acoustic wave propagation in standing trees. Two-layer tree models with various diameters and proportions of juvenile wood were constructed to examine the effects of these two factors on propagation patterns and velocity of acoustic waves. The simulation results and analysis indicated that acoustic wave propagation in trees is dependent on both tree diameter and propagation distance. In the context of time-of-flight (TOF) acoustic measurement on standing trees with a test span of 1.2 m, when tree diameter is 10 cm or less, or slenderness is twelve or greater, wave propagates as quasi-plane waves in tree trunk, and the tree velocity determined using the TOF method is then comparable to the log velocity measured using the acoustic resonance method. When tree diameter is 40 cm or larger, or slenderness is three or less, wave propagates as dilatational waves in the tree trunk; thus, the three-dimensional wave equation should be considered for wood property prediction. When tree diameter falls between 10 and 40 cm or slenderness falls between 3 and 12, wave propagation is in a transitional phase. Mathematical models were developed to convert the tree velocity in the transition mode to the resonance velocity. It was found that juvenile wood content resulted in a 113-m/s reduction in acoustic velocity. In addition, our analysis indicated that wave propagation in standing trees is controlled by the wood properties of entire cross section, not just the outerwood. Therefore, the wave velocity measured on standing trees reflects the global properties of the wood between the two measuring points.","PeriodicalId":23620,"journal":{"name":"Wood and Fiber Science","volume":"53 1","pages":"95-108"},"PeriodicalIF":1.4,"publicationDate":"2021-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48756068","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}
As a powerful tool to investigate the surface properties at a nano-scale resolution, the atomic force microscopy (AFM) encounters challenges in the measurement of plant materials such as wood surface. In particular, for rough and heterogeneous surfaces, a robust and easily performed positioning method is necessary for reproducible measurements. One of the critical issues is the ability to position the AFM tip after the specimens are removed for treatments from a device and repeatedly analyzed. If the tip is not repeatably positioned within the measured area, the natural variability of surface (such as surface roughness) can mask the effects of treatments of interest. In this paper, a positioning method using the bordered pit of the wood radial surface as a natural marker is proposed and a systematic measurement procedure is presented. The idea results from the uniqueness of the anatomical features of a natural material (wood in this case) and low probability of having exactly the same geometry of pit clusters in the vicinity of the area of interest. The results show that the anatomical features can be used as unique markers for precise positioning of the AFM tip. The process is demonstrated using an example of the effect of temperature on adhesion forces on the wood surface. After the heat treatment, the wood surface layers were investigated with Fourier transform infrared spectroscopy and attenuated total reflection (FTIR-ATR).
{"title":"Repeatability of Adhesion Force Measurement on Wood Longitunial Cut Cell Wall Using Atomic Force Microscopy","authors":"Juan Li, Kasal Bohumil","doi":"10.22382/WFS-2021-02","DOIUrl":"https://doi.org/10.22382/WFS-2021-02","url":null,"abstract":"As a powerful tool to investigate the surface properties at a nano-scale resolution, the atomic force microscopy (AFM) encounters challenges in the measurement of plant materials such as wood surface. In particular, for rough and heterogeneous surfaces, a robust and easily performed positioning method is necessary for reproducible measurements. One of the critical issues is the ability to position the AFM tip after the specimens are removed for treatments from a device and repeatedly analyzed. If the tip is not repeatably positioned within the measured area, the natural variability of surface (such as surface roughness) can mask the effects of treatments of interest. In this paper, a positioning method using the bordered pit of the wood radial surface as a natural marker is proposed and a systematic measurement procedure is presented. The idea results from the uniqueness of the anatomical features of a natural material (wood in this case) and low probability of having exactly the same geometry of pit clusters in the vicinity of the area of interest. The results show that the anatomical features can be used as unique markers for precise positioning of the AFM tip. The process is demonstrated using an example of the effect of temperature on adhesion forces on the wood surface. After the heat treatment, the wood surface layers were investigated with Fourier transform infrared spectroscopy and attenuated total reflection (FTIR-ATR).","PeriodicalId":23620,"journal":{"name":"Wood and Fiber Science","volume":"53 1","pages":"3-16"},"PeriodicalIF":1.4,"publicationDate":"2021-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47642679","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}
Guangmei Cao Anderson, F. Owens, S. Verrill, R. Ross, R. Shmulsky
It has been mathematically demonstrated that the distribution of modulus of rupture (MOR) in a graded lumber subpopulation does not have the same theoretical form as the distribution of the mill-run population from which the subpopulation is drawn. However, the distributional form of the graded lumber subpopulation does depend heavily on the distributional form of the full mill-run population, and thus it is important to characterize the distributions of full mill-run lumber populations. Previous studies presented evidence suggesting that commonly-used distributions such as normal, lognormal, and Weibull distributions might not be suitable for modeling mill-run modulus of elasticity (MOE) and MOR; rather, nontraditional distributions such as skew-normal and mixed normal seem to be more appropriate models for the MOE and MOR of mill-run populations across mills and time. Previous studies of this kind have been carried out using only southern pine ( Pinus spp.) lumber. In this study, we extend this work by investigating whether the distributional forms found to adequately fit southern pine mill-run lumber populations also adequately fit other species (or species groups). The objective of this study is to identify statistical models that fit MOE and MOR distributions in mill-run spruce ( Picea spp.) and red pine ( Pinus resinosa ) lumber populations. Mill-run samples of 200 spruce 2 × 4 specimens and 200 red pine 2 × 4 specimens (for a total of 400 test pieces) were collected, and the MOE and MOR for each specimen were assessed. Various distributions were fit to the MOE and MOR mill-run data and evaluated for goodness-of-fit. In addition to further demonstrating that traditional distributions such as normal, lognormal, and Weibull may not be adequate to model mill run MOE and MOR populations, the results suggested that mixed normal and skew normal distributions might perform well across species.
{"title":"Fitting Statistical Distribution Models to MOE and MOR in Mill-Run Spruce and Red Pine Lumber Populations","authors":"Guangmei Cao Anderson, F. Owens, S. Verrill, R. Ross, R. Shmulsky","doi":"10.22382/WFS-2021-03","DOIUrl":"https://doi.org/10.22382/WFS-2021-03","url":null,"abstract":"It has been mathematically demonstrated that the distribution of modulus of rupture (MOR) in a graded lumber subpopulation does not have the same theoretical form as the distribution of the mill-run population from which the subpopulation is drawn. However, the distributional form of the graded lumber subpopulation does depend heavily on the distributional form of the full mill-run population, and thus it is important to characterize the distributions of full mill-run lumber populations. Previous studies presented evidence suggesting that commonly-used distributions such as normal, lognormal, and Weibull distributions might not be suitable for modeling mill-run modulus of elasticity (MOE) and MOR; rather, nontraditional distributions such as skew-normal and mixed normal seem to be more appropriate models for the MOE and MOR of mill-run populations across mills and time. Previous studies of this kind have been carried out using only southern pine ( Pinus spp.) lumber. In this study, we extend this work by investigating whether the distributional forms found to adequately fit southern pine mill-run lumber populations also adequately fit other species (or species groups). The objective of this study is to identify statistical models that fit MOE and MOR distributions in mill-run spruce ( Picea spp.) and red pine ( Pinus resinosa ) lumber populations. Mill-run samples of 200 spruce 2 × 4 specimens and 200 red pine 2 × 4 specimens (for a total of 400 test pieces) were collected, and the MOE and MOR for each specimen were assessed. Various distributions were fit to the MOE and MOR mill-run data and evaluated for goodness-of-fit. In addition to further demonstrating that traditional distributions such as normal, lognormal, and Weibull may not be adequate to model mill run MOE and MOR populations, the results suggested that mixed normal and skew normal distributions might perform well across species.","PeriodicalId":23620,"journal":{"name":"Wood and Fiber Science","volume":"53 1","pages":"17-26"},"PeriodicalIF":1.4,"publicationDate":"2021-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46777447","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}
The empirical test developed as validation for a new beam element model that can account for both mechanical and environmental load action in finite element analysis is presented. The testing protocol allows for the identification and analysis of contributing deflection components in bending under varying MC conditions, including mechano-sorption. The components of deflection in the shear-free span of a four-point bending test and their responses to varying moisture are evaluated with an analytical procedure. The experiment was conducted on clear-straight-grained sapwood and heartwood specimens of Norway spruce ( Picea Abies )(30 x 15 x 640 mm 3) . The program consisted of three phases: (1.) long term (LT) experiments under constant temperature of 60 o C and relative humidity (RH) cycles between 40% and 80%, (2.) a short term static experiment to determine the variation in the sample set and the load-level of the LT experiment on end-matched specimens, and (3) creep tests at 60 o and constant humidity at either 40% or 80% to determine the effect of moisture on the viscoelastic creep. Mass changes and hygro-expansion measured on matched specimens were used in the analytical method. Constitutive models used for describing the material-level response to loads and moisture changes were applied to the shear-free segment of the specimens disregarding actual moisture gradients and fiber orientation inside the test specimens. A successful identification of each deflection component and isolation of mechano-sorption component was accomplished. In the 90 da of testing, the dominant component of the total deflection was the elastic component, followed by the mechano-sorptive component. Creep was found to be nonnegligible and important in the correct description of mechano-sorption. The effect of moisture on the viscoelastic behavior showed most important during loading and first stages of decreasing deflection rate phase.
提出了一种新的梁单元模型的经验试验，该模型可以在有限元分析中同时考虑机械和环境载荷作用。测试方案允许在不同的MC条件下，包括机械吸附条件下，识别和分析弯曲中的贡献偏转成分。用分析程序评估了四点弯曲试验的自由剪切跨度中的挠度分量及其对不同湿度的响应。实验是在挪威云杉（Picea Abies）（30 x 15 x 640 mm 3）的清晰直纹边材和心材标本上进行的。该程序由三个阶段组成：（1.）在60°C的恒温和40%至80%的相对湿度（RH）循环下的长期（LT）实验，和（3）在60°和40%或80%的恒定湿度下的蠕变试验，以确定水分对粘弹性蠕变的影响。在分析方法中使用了在匹配样品上测量的质量变化和湿膨胀。用于描述材料水平对载荷和湿度变化的响应的本构模型应用于试样的无剪切段，而不考虑试样内的实际湿度梯度和纤维取向。成功地识别了每个偏转成分并分离了机械吸附成分。在90 da的测试中，总挠度的主要成分是弹性成分，其次是机械吸收成分。蠕变被发现是不可忽略的，并且在机械吸附的正确描述中很重要。水分对粘弹性行为的影响在加载和降低挠度阶段的第一阶段表现得最为重要。
{"title":"ANALYSIS OF HYGRO-MECHANICAL BEHAVIOR OF WOOD IN BENDING","authors":"S. Florisson, L. Muszynski, J. Vessby","doi":"10.22382/WFS-2021-04","DOIUrl":"https://doi.org/10.22382/WFS-2021-04","url":null,"abstract":"The empirical test developed as validation for a new beam element model that can account for both mechanical and environmental load action in finite element analysis is presented. The testing protocol allows for the identification and analysis of contributing deflection components in bending under varying MC conditions, including mechano-sorption. The components of deflection in the shear-free span of a four-point bending test and their responses to varying moisture are evaluated with an analytical procedure. The experiment was conducted on clear-straight-grained sapwood and heartwood specimens of Norway spruce ( Picea Abies )(30 x 15 x 640 mm 3) . The program consisted of three phases: (1.) long term (LT) experiments under constant temperature of 60 o C and relative humidity (RH) cycles between 40% and 80%, (2.) a short term static experiment to determine the variation in the sample set and the load-level of the LT experiment on end-matched specimens, and (3) creep tests at 60 o and constant humidity at either 40% or 80% to determine the effect of moisture on the viscoelastic creep. Mass changes and hygro-expansion measured on matched specimens were used in the analytical method. Constitutive models used for describing the material-level response to loads and moisture changes were applied to the shear-free segment of the specimens disregarding actual moisture gradients and fiber orientation inside the test specimens. A successful identification of each deflection component and isolation of mechano-sorption component was accomplished. In the 90 da of testing, the dominant component of the total deflection was the elastic component, followed by the mechano-sorptive component. Creep was found to be nonnegligible and important in the correct description of mechano-sorption. The effect of moisture on the viscoelastic behavior showed most important during loading and first stages of decreasing deflection rate phase.","PeriodicalId":23620,"journal":{"name":"Wood and Fiber Science","volume":"53 1","pages":"27-47"},"PeriodicalIF":1.4,"publicationDate":"2021-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43111849","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":"Review of Book, The Baseball Bat: From Trees to the Major Leagues, 19th Century to Today authored by Stephen Bratkovich","authors":"S. Levan-Green","doi":"10.22382/WFS-2021-09","DOIUrl":"https://doi.org/10.22382/WFS-2021-09","url":null,"abstract":"","PeriodicalId":23620,"journal":{"name":"Wood and Fiber Science","volume":"53 1","pages":"78-78"},"PeriodicalIF":1.4,"publicationDate":"2021-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42667627","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}
Hua Wang, Mugaanire tendo Innocent, H. Memon, Xiao-juan Jin, Feichao Zhu
In this study, cellulose films were prepared from Ficus natalensis bark cloth fibers via phase inversion technique using NaOH/urea/water as the solvent. Films were formed at a concentration of 7 wt. % and 8 wt. % of microcrystalline cellulose (MCC) as isolated from Ficus natalensis bark cloth fibers. Their morphology, physiochemical, and mechanical properties were examined with scanning electron microscopy (SEM), Fourier transform IR spectroscopy (FTIR), x-ray diffraction (XRD), thermal gravimetric analysis (TGA) and microcontrolled electronic universal testing machine. The resultant regenerated cellulose (RC) films exhibited rough surfaces morphologically, good tensile strength (19.85 ± 0.13 MPa), exhibited a plastic behavior with considerable strains. However, they are thermally stable at higher temperatures up to 280 °C. Cellulose films from this study could potentially act as biodegradable packaging materials to upgrade the scope of application of Ficus natalensis bark
{"title":"PREPARATION AND CHARACTERIZATION OF CELLULOSE FILMS FROM FICUS NATALENSIS BARK CLOTH FIBERS","authors":"Hua Wang, Mugaanire tendo Innocent, H. Memon, Xiao-juan Jin, Feichao Zhu","doi":"10.22382/WFS-2021-06","DOIUrl":"https://doi.org/10.22382/WFS-2021-06","url":null,"abstract":"In this study, cellulose films were prepared from Ficus natalensis bark cloth fibers via phase inversion technique using NaOH/urea/water as the solvent. Films were formed at a concentration of 7 wt. % and 8 wt. % of microcrystalline cellulose (MCC) as isolated from Ficus natalensis bark cloth fibers. Their morphology, physiochemical, and mechanical properties were examined with scanning electron microscopy (SEM), Fourier transform IR spectroscopy (FTIR), x-ray diffraction (XRD), thermal gravimetric analysis (TGA) and microcontrolled electronic universal testing machine. The resultant regenerated cellulose (RC) films exhibited rough surfaces morphologically, good tensile strength (19.85 ± 0.13 MPa), exhibited a plastic behavior with considerable strains. However, they are thermally stable at higher temperatures up to 280 °C. Cellulose films from this study could potentially act as biodegradable packaging materials to upgrade the scope of application of Ficus natalensis bark","PeriodicalId":23620,"journal":{"name":"Wood and Fiber Science","volume":"53 1","pages":"62-68"},"PeriodicalIF":1.4,"publicationDate":"2021-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44218200","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}
Franacesco Negro, C. Cremonini, M. Fringuellino, F. Meloni, Stefano Prina, R. Zanuttini
This study investigates the possibility of exploiting the porous structure of wood for absorbing sound. With this aim, the following system is proposed: 1 ) the cross section of wood should be exposed to sound waves so that these can activate the vibration of air inside the wood pores; 2) the cross section should be cut to have small thickness to realize a thorough open cell absorber; 3 ) a void cavity should be left on the back to activate the absorption effect. This setup has been conceived to absorb sound by Helmoltz resonance. To preliminary assess the effectiveness of the system, cross sections of poplar wood were cut 1 mm thick and paired with rear void cavities 15, 30 and 50 mm thick. The normal sound absorption coefficient α was determined through the impedance tube method. Multiple absorption peaks and several α values higher than 0.6-0.7 (α max =0.99) were measured in the medium-low frequency range. Building on these results, further studies are envisaged to model the acoustic behavior of the system and to set the technical aspects relevant to its feasibility in practice.
{"title":"Sound Absorbing Systems Made of Wood cross Sections Paired with Void Cavities - A First Investigation","authors":"Franacesco Negro, C. Cremonini, M. Fringuellino, F. Meloni, Stefano Prina, R. Zanuttini","doi":"10.22382/WFS-2021-07","DOIUrl":"https://doi.org/10.22382/WFS-2021-07","url":null,"abstract":"This study investigates the possibility of exploiting the porous structure of wood for absorbing sound. With this aim, the following system is proposed: 1 ) the cross section of wood should be exposed to sound waves so that these can activate the vibration of air inside the wood pores; 2) the cross section should be cut to have small thickness to realize a thorough open cell absorber; 3 ) a void cavity should be left on the back to activate the absorption effect. This setup has been conceived to absorb sound by Helmoltz resonance. To preliminary assess the effectiveness of the system, cross sections of poplar wood were cut 1 mm thick and paired with rear void cavities 15, 30 and 50 mm thick. The normal sound absorption coefficient α was determined through the impedance tube method. Multiple absorption peaks and several α values higher than 0.6-0.7 (α max =0.99) were measured in the medium-low frequency range. Building on these results, further studies are envisaged to model the acoustic behavior of the system and to set the technical aspects relevant to its feasibility in practice.","PeriodicalId":23620,"journal":{"name":"Wood and Fiber Science","volume":"53 1","pages":"69-76"},"PeriodicalIF":1.4,"publicationDate":"2021-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44763822","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}
In this study, the effects of the wood species of dowels and the end distance were examined relative to the moment resistance of L-type corner joints with catch connector (ClamexP14) and three different wood species of dowels were used as specimen (as used in the furniture industry). L-type joint specimens 297 mm long were tested under static diagonal compression loads for determining the bending moment capacity. The results showed that the Orientalis beech dowel had the highest bending moment resistance under compression. Regarding the end distance, the highest bending moment resistance was obtained from an end distance of 60 mm.
{"title":"AN INVESTIGATION ON THE EFFECTS OF WOODEN SPECIES OF DOWELS AND THE END DISTANCE OF CATCH CONNECTORS (CLAMEXP14) ON THE BENDING MOMENT OF L-TYPE CORNER JOINTS FOR RTA (READY TO ASSEMBLE) FURNITURE","authors":"A. Karaman","doi":"10.22382/WFS-2021-05","DOIUrl":"https://doi.org/10.22382/WFS-2021-05","url":null,"abstract":"In this study, the effects of the wood species of dowels and the end distance were examined relative to the moment resistance of L-type corner joints with catch connector (ClamexP14) and three different wood species of dowels were used as specimen (as used in the furniture industry). L-type joint specimens 297 mm long were tested under static diagonal compression loads for determining the bending moment capacity. The results showed that the Orientalis beech dowel had the highest bending moment resistance under compression. Regarding the end distance, the highest bending moment resistance was obtained from an end distance of 60 mm.","PeriodicalId":23620,"journal":{"name":"Wood and Fiber Science","volume":"53 1","pages":"48-61"},"PeriodicalIF":1.4,"publicationDate":"2021-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43640479","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}
Table 4.2-5 Summary of Project Operational Emissions (pounds per day) Source ROG NOx CO SOx PM10 PM2.5 Area Sources 1 >1 >1 >1 >1 >1 Energy Sources >1 >1 >1 >1 >1 >1 Mobile Sources 23 118 368 1 106 29 Total 23 118 369 1 106 29 Screening Threshold 250 250 550 250 100 67 Significant? No No No No No* No NOTE: Totals may vary due to independent rounding. * While daily PM10 emissions associated with the project would exceed the applicable daily screening threshold during the maximum potential events (10,000-seat events), which shall only occur 6 times a year, buildout of the project site (i.e. maximum annual attendance) would result in PM10 emissions of 2.7 tons per year (or an average of 15 pounds of PM10 per day); please see Attachment 1, Maximum 2020 Event and 2030 Project Buildout. Therefore, the project would not result in a direct or cumulative contribution to a regional or local exceedance of air quality standards and PM10 emissions are considered less than significant.
{"title":"Errata Sheet","authors":"S. Levan-Green","doi":"10.22382/wfs-2018-023","DOIUrl":"https://doi.org/10.22382/wfs-2018-023","url":null,"abstract":"Table 4.2-5 Summary of Project Operational Emissions (pounds per day) Source ROG NOx CO SOx PM10 PM2.5 Area Sources 1 >1 >1 >1 >1 >1 Energy Sources >1 >1 >1 >1 >1 >1 Mobile Sources 23 118 368 1 106 29 Total 23 118 369 1 106 29 Screening Threshold 250 250 550 250 100 67 Significant? No No No No No* No NOTE: Totals may vary due to independent rounding. * While daily PM10 emissions associated with the project would exceed the applicable daily screening threshold during the maximum potential events (10,000-seat events), which shall only occur 6 times a year, buildout of the project site (i.e. maximum annual attendance) would result in PM10 emissions of 2.7 tons per year (or an average of 15 pounds of PM10 per day); please see Attachment 1, Maximum 2020 Event and 2030 Project Buildout. Therefore, the project would not result in a direct or cumulative contribution to a regional or local exceedance of air quality standards and PM10 emissions are considered less than significant.","PeriodicalId":23620,"journal":{"name":"Wood and Fiber Science","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2021-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46665996","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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