Pub Date : 2022-05-01DOI: 10.5658/wood.2022.50.3.186
E. Jang
This study examined the utility of pine (Pinus densiflora) pollen cones as an environmentally friendly material with sound-absorbing properties. Pine pollen cone samples with widths of 0.8–1.2 cm and lengths of 3.5–4.5 cm were prepared. After filling impedance tubes to heights of 6, 8, 10, or 12 cm with the pine pollen cones, the sound absorption coefficient of the pine pollen cones was investigated. The peak sound absorption frequency of the samples with a thickness of 6 cm was reached at 1,512 Hz; however, this value shifted to 740 Hz in samples with a thickness of 12 cm. Therefore, the sound-absorbing performance of pine pollen cones at low frequencies improved as the material thickness increased. According to KS F 3503 (Korean Standards Association), the sound absorption grade of pine pollen cones ranges from 0.3 to 0.5 M, depending on the material thickness of the pine pollen cones. In conclusion, the pine pollen cones demonstrated good sound absorption properties. They, thus, may be considered an environmentally friendly sound-absorbing material.
本研究考察了赤松球果作为一种具有吸声性能的环保材料的实用性。制备了宽0.8–1.2厘米、长3.5–4.5厘米的松花粉锥样品。用松花粉锥填充阻抗管至6、8、10或12cm的高度后，研究了松花粉锥的吸声系数。厚度为6cm的样品的峰值吸声频率达到1512Hz；然而，在厚度为12cm的样品中，这一值偏移到了740Hz。因此，随着材料厚度的增加，松花粉锥在低频下的吸声性能有所改善。根据KS F 3503（韩国标准协会），松花粉锥的吸声等级在0.3至0.5M之间，具体取决于松花粉锥材料的厚度。总之，松花粉锥表现出良好的吸声性能。因此，它们可以被认为是一种对环境友好的吸声材料。
{"title":"Use of Pine (Pinus densiflora) Pollen Cones as an Environmentally Friendly Sound-Absorbing Material","authors":"E. Jang","doi":"10.5658/wood.2022.50.3.186","DOIUrl":"https://doi.org/10.5658/wood.2022.50.3.186","url":null,"abstract":"This study examined the utility of pine (Pinus densiflora) pollen cones as an environmentally friendly material with sound-absorbing properties. Pine pollen cone samples with widths of 0.8–1.2 cm and lengths of 3.5–4.5 cm were prepared. After filling impedance tubes to heights of 6, 8, 10, or 12 cm with the pine pollen cones, the sound absorption coefficient of the pine pollen cones was investigated. The peak sound absorption frequency of the samples with a thickness of 6 cm was reached at 1,512 Hz; however, this value shifted to 740 Hz in samples with a thickness of 12 cm. Therefore, the sound-absorbing performance of pine pollen cones at low frequencies improved as the material thickness increased. According to KS F 3503 (Korean Standards Association), the sound absorption grade of pine pollen cones ranges from 0.3 to 0.5 M, depending on the material thickness of the pine pollen cones. In conclusion, the pine pollen cones demonstrated good sound absorption properties. They, thus, may be considered an environmentally friendly sound-absorbing material.","PeriodicalId":17357,"journal":{"name":"Journal of the Korean wood science and technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46576846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-05-01DOI: 10.5658/wood.2022.50.4.272
Jiyoon Yang, Won-sil Choi, Su-Yeon Lee, Minju Kim, M. Park
The essential oil extracted from Citrus × natsudaidai (Yu. Tanaka) Hayata peels is known to have various biological properties. However, the chemical composition of essential oil is influenced by the ripening stages of fruits, which then affects related biological activities. This study investigates the antioxidant activities of essential oils extracted from Citrus × natsudaidai peels at different ripening stages (immature, mature, and overripe). The essential oils were extracted using the hydro-distillation method. As a result of gas chromatography-mass spectrometry (GC-MS) analysis, d-limonene was dominant and was increased as matured. However, γ-terpinene was decreased. The antioxidant properties and their total phenolic content (TPC) were influenced by the ripening stages. The TPC was highest in the immature stage of essential oil (1,011.25 ± 57.15 mg GAE/100 g). 2,2‐Diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging activity was excellent in the immature stage (EC 50 = 15.91 ± 0.38 mg/mL). 2,2’-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity was superior in overripe stage (EC 50 = 20.43 ± 0.37 mg/mL). The antioxidant activity measured using ferric reducing antioxidant power (FRAP) assay showed higher values for the essential oils in immaturity (1,342.37 ± 71.07 mg Fe 2+ /100 g). Comprehensively, the essential oil in the immature stage showed the best antioxidant activity. Finally, knowing the chemical composition and antioxidant activity at different ripening stages will provide data for selecting the right fruit.
{"title":"Antioxidant Activities of Essential Oils from Citrus\u0000 × natsudaidai (Yu. Tanaka) Hayata Peels at Different\u0000 Ripening Stage","authors":"Jiyoon Yang, Won-sil Choi, Su-Yeon Lee, Minju Kim, M. Park","doi":"10.5658/wood.2022.50.4.272","DOIUrl":"https://doi.org/10.5658/wood.2022.50.4.272","url":null,"abstract":"The essential oil extracted from Citrus × natsudaidai (Yu. Tanaka) Hayata peels is known to have various biological properties. However, the chemical composition of essential oil is influenced by the ripening stages of fruits, which then affects related biological activities. This study investigates the antioxidant activities of essential oils extracted from Citrus × natsudaidai peels at different ripening stages (immature, mature, and overripe). The essential oils were extracted using the hydro-distillation method. As a result of gas chromatography-mass spectrometry (GC-MS) analysis, d-limonene was dominant and was increased as matured. However, γ-terpinene was decreased. The antioxidant properties and their total phenolic content (TPC) were influenced by the ripening stages. The TPC was highest in the immature stage of essential oil (1,011.25 ± 57.15 mg GAE/100 g). 2,2‐Diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging activity was excellent in the immature stage (EC 50 = 15.91 ± 0.38 mg/mL). 2,2’-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity was superior in overripe stage (EC 50 = 20.43 ± 0.37 mg/mL). The antioxidant activity measured using ferric reducing antioxidant power (FRAP) assay showed higher values for the essential oils in immaturity (1,342.37 ± 71.07 mg Fe 2+ /100 g). Comprehensively, the essential oil in the immature stage showed the best antioxidant activity. Finally, knowing the chemical composition and antioxidant activity at different ripening stages will provide data for selecting the right fruit.","PeriodicalId":17357,"journal":{"name":"Journal of the Korean wood science and technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44969480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-05-01DOI: 10.5658/wood.2022.50.3.149
Jun-Sun Bang, Jungkyu Kim, Y. Kim, J. Oh, H. Yeo, H. Kwak
To realize the infinite possibilities of materials derived from wood, it is necessary to overcome the weak moisture stability of wood. Thus, the development of an eco-friendly hydrophobic coating agent is essential, and of these, woody biomass-based materials are strongly attractive as coatings. In this study, eco-friendly hydrophobic wood coatings were prepared using carnauba wax purified from palm leaves and sprouts, and kraft lignin. The physicochemical properties of the carnauba wax/lignin blends according to the ratio of carnauba wax and lignin were observed by morphology and functional group change. In addition, the coating performance of carnauba wax/lignin blend coatings was confirmed by measuring the contact angle change. It was found that the addition of lignin could accelerate the atomization of wax particles, and that micro-roughness can be realized when applied to the actual wood surface, to ensure that the coating effect over time lasts longer. In addition, it was confirmed that the addition of lignin increases the hydrogen-bond-based interaction with the wood of the coating, thereby providing better coating stability and increasing the durability of the coating solvent under friction. The carnauba wax/lignin paint developed in this way is eco-friendly because all components are made of wood-based raw materials and have an excellent affinity with wood surfaces. Therefore, it is expected to be applicable to the coating process of wood-plastic composites and timber composites.
{"title":"Preparation and Characterization of Hydrophobic Coatings from Carnauba Wax/Lignin Blends","authors":"Jun-Sun Bang, Jungkyu Kim, Y. Kim, J. Oh, H. Yeo, H. Kwak","doi":"10.5658/wood.2022.50.3.149","DOIUrl":"https://doi.org/10.5658/wood.2022.50.3.149","url":null,"abstract":"To realize the infinite possibilities of materials derived from wood, it is necessary to overcome the weak moisture stability of wood. Thus, the development of an eco-friendly hydrophobic coating agent is essential, and of these, woody biomass-based materials are strongly attractive as coatings. In this study, eco-friendly hydrophobic wood coatings were prepared using carnauba wax purified from palm leaves and sprouts, and kraft lignin. The physicochemical properties of the carnauba wax/lignin blends according to the ratio of carnauba wax and lignin were observed by morphology and functional group change. In addition, the coating performance of carnauba wax/lignin blend coatings was confirmed by measuring the contact angle change. It was found that the addition of lignin could accelerate the atomization of wax particles, and that micro-roughness can be realized when applied to the actual wood surface, to ensure that the coating effect over time lasts longer. In addition, it was confirmed that the addition of lignin increases the hydrogen-bond-based interaction with the wood of the coating, thereby providing better coating stability and increasing the durability of the coating solvent under friction. The carnauba wax/lignin paint developed in this way is eco-friendly because all components are made of wood-based raw materials and have an excellent affinity with wood surfaces. Therefore, it is expected to be applicable to the coating process of wood-plastic composites and timber composites.","PeriodicalId":17357,"journal":{"name":"Journal of the Korean wood science and technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47369203","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-01DOI: 10.5658/wood.2022.50.2.104
Jung-Woo Hwang, Seung-Won Oh
Indoor air quality is a very important environmental factor in modern society. However, air pollutants generated from various interior construction materials significantly affect the human body, including formaldehyde (HCHO) and volatile organic compounds that threaten public health by deteriorating indoor air quality. Effective in removing these harmful substances are porous materials, such as woodceramics. In this study, charcoal, a porous material, was added to rice husk, an agricultural by-product, and sawdust generated during the sawing process to prepare boards and ceramics at different mixing ratios, and the HCHO deodorization performance and far-infrared emission characteristics were measured. As the mixing ratio of charcoal increased, the deodorization rate of the boards and ceramics tended to increase. Overall, the deodorization rate was measured to be 80% to 90%, indicating that the boards and ceramics prepared with charcoal are suitable to be used for the purpose of deodorization. The effect of the material mixing ratio on far-infrared emissivity and emission power was insignificant.
{"title":"Formaldehyde Deodorization Effect and Far-Infrared Emission Characteristics of Ceramics Prepared with Sawdust, Risk Husk, and Charcoal: Effect of Material Mixing Ratio","authors":"Jung-Woo Hwang, Seung-Won Oh","doi":"10.5658/wood.2022.50.2.104","DOIUrl":"https://doi.org/10.5658/wood.2022.50.2.104","url":null,"abstract":"Indoor air quality is a very important environmental factor in modern society. However, air pollutants generated from various interior construction materials significantly affect the human body, including formaldehyde (HCHO) and volatile organic compounds that threaten public health by deteriorating indoor air quality. Effective in removing these harmful substances are porous materials, such as woodceramics. In this study, charcoal, a porous material, was added to rice husk, an agricultural by-product, and sawdust generated during the sawing process to prepare boards and ceramics at different mixing ratios, and the HCHO deodorization performance and far-infrared emission characteristics were measured. As the mixing ratio of charcoal increased, the deodorization rate of the boards and ceramics tended to increase. Overall, the deodorization rate was measured to be 80% to 90%, indicating that the boards and ceramics prepared with charcoal are suitable to be used for the purpose of deodorization. The effect of the material mixing ratio on far-infrared emissivity and emission power was insignificant.","PeriodicalId":17357,"journal":{"name":"Journal of the Korean wood science and technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47806748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-01DOI: 10.5658/wood.2022.50.2.93
T. Setyayunita, R. Widyorini, S. N. Marsoem, D. Irawati
Currently, biofibers are used as a reinforcement in polymer composites for structural elements and construction materials instead of the synthetic fibers which cause environmental problems and are expensive. One of the chemicals with a pH close to neutral that can be potentially used as a modified fiber material is sodium chloride (NaCl). Therefore, this study aims to investigate the characteristics of a composite board made from NaCl-treated kenaf fiber. A completely randomized design method was used with consideration of two factors: the content of NaCl in the treatment solution (1 wt%, 3 wt%, and 5 wt%) and the duration of immersion of fibers in the solution (1 h, 2 h, and 3 h). The NaCl treatment was conducted by soaking the fibers in the solution for different durations. The fibers were then rinsed with water until the pH of the water reached 7 and subsequently dried inside an oven at 80 ℃ for 6 h. Kenaf fiber and epoxy were mixed manually with the total loading of 20 wt% based on the dry weight of the fiber. Physical and mechanical properties of the fibers were then evaluated based on JIS A 5908 particleboard standards. The results showed that increasing NaCl content in the fiber treatment solution can increase the physical and mechanical properties of the composite board. The properties of fibers treated with 5 wt% NaCl for 3 h were superior with a modulus of elasticity of 2.085 GPa, modulus of rupture of 19.77 MPa, internal bonding of 1.8 MPa, thickness swelling of 3%, and water absorption of 10.9%. The contact angle of untreated kenaf fibers was 104°, which increased to 80° and 73° on treatment with 1 wt% and 5 wt% NaCl for 3 h, respectively.
目前，生物纤维被用作结构元件和建筑材料的聚合物复合材料的增强材料，而不是引起环境问题且价格昂贵的合成纤维。氯化钠（NaCl）是一种pH接近中性的化学物质，有可能用作改性纤维材料。因此，本研究旨在研究由NaCl处理的红麻纤维制成的复合板的特性。采用完全随机设计方法，考虑两个因素：处理溶液中NaCl的含量（1wt%、3wt%和5wt%）和纤维在溶液中的浸泡时间（1h、2h和3h）。通过将纤维在溶液中浸泡不同的持续时间来进行NaCl处理。然后用水冲洗纤维，直到水的pH达到7，然后在80℃的烘箱中干燥6小时。手动混合红麻纤维和环氧树脂，总负载量为纤维干重的20wt%。然后根据JIS A 5908刨花板标准对纤维的物理和机械性能进行评估。结果表明，增加纤维处理液中NaCl的含量可以提高复合板的物理力学性能。用5wt%的NaCl处理3h的纤维性能优异，弹性模量为2.085GPa，断裂模量为19.77MPa，内部结合为1.8MPa，厚度溶胀为3%，吸水率为10.9%。未处理红麻纤维的接触角为104°，用1wt%和5wt%的氯化钠处理3h后，接触角分别增加到80°和73°。
{"title":"Effect of Different Conditions of Sodium Chloride Treatment on the Characteristics of Kenaf Fiber-Epoxy Composite Board","authors":"T. Setyayunita, R. Widyorini, S. N. Marsoem, D. Irawati","doi":"10.5658/wood.2022.50.2.93","DOIUrl":"https://doi.org/10.5658/wood.2022.50.2.93","url":null,"abstract":"Currently, biofibers are used as a reinforcement in polymer composites for structural elements and construction materials instead of the synthetic fibers which cause environmental problems and are expensive. One of the chemicals with a pH close to neutral that can be potentially used as a modified fiber material is sodium chloride (NaCl). Therefore, this study aims to investigate the characteristics of a composite board made from NaCl-treated kenaf fiber. A completely randomized design method was used with consideration of two factors: the content of NaCl in the treatment solution (1 wt%, 3 wt%, and 5 wt%) and the duration of immersion of fibers in the solution (1 h, 2 h, and 3 h). The NaCl treatment was conducted by soaking the fibers in the solution for different durations. The fibers were then rinsed with water until the pH of the water reached 7 and subsequently dried inside an oven at 80 ℃ for 6 h. Kenaf fiber and epoxy were mixed manually with the total loading of 20 wt% based on the dry weight of the fiber. Physical and mechanical properties of the fibers were then evaluated based on JIS A 5908 particleboard standards. The results showed that increasing NaCl content in the fiber treatment solution can increase the physical and mechanical properties of the composite board. The properties of fibers treated with 5 wt% NaCl for 3 h were superior with a modulus of elasticity of 2.085 GPa, modulus of rupture of 19.77 MPa, internal bonding of 1.8 MPa, thickness swelling of 3%, and water absorption of 10.9%. The contact angle of untreated kenaf fibers was 104°, which increased to 80° and 73° on treatment with 1 wt% and 5 wt% NaCl for 3 h, respectively.","PeriodicalId":17357,"journal":{"name":"Journal of the Korean wood science and technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44297739","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-01DOI: 10.5658/wood.2022.50.2.134
I. Sumardi, E. M. Alamsyah, Y. Suhaya, R. Dungani, I. M. Sulastiningsih, Syahdilla Risandra Pramestie
The objective of this study is to determine the effect of fiber direction arrangement and layer composition of hybrid bamboo laminate boards on the physical and mechanical properties. The raw material used was tali bamboo ( Gigantochloa apus (J.A. Schultes) Kurs) rope in the form of flat sheets (zephyr) and falcata veneer ( Paraserianthes falcataria (L) Nielsen). Zephyr bamboo was arranged in three layers using water-based isocyanate polymer (WBPI) with a glue spread rate of 300 g/m 2 . There were variations in the substitution of the core layer with falcata veneers (hybrid) as much as two layers and using a glue spread rate of 170 g/m 2 . The laminated bamboo board was cold-pressed at a pressure of 22.2 kgf/cm 2 for 1 h, and the physical and mechanical properties were evaluated. The results showed that the arrangement of the fiber direction significantly affected the dimensional stability, modulus of rupture, modulus of elasticity, shear strength, and screw withdrawal strength. However, the composition of the layers had no significant effect on the physical and mechanical properties. The bonding quality of bamboo laminate boards with WBPI was considered to be quite good, as shown by the absence of delamination in all test samples. The bamboo hybrid laminate board can be an alternative based on the physical and mechanical properties that can meet laminated board standards.
{"title":"Development of Bamboo Zephyr Composite and the Physical and Mechanical Properties","authors":"I. Sumardi, E. M. Alamsyah, Y. Suhaya, R. Dungani, I. M. Sulastiningsih, Syahdilla Risandra Pramestie","doi":"10.5658/wood.2022.50.2.134","DOIUrl":"https://doi.org/10.5658/wood.2022.50.2.134","url":null,"abstract":"The objective of this study is to determine the effect of fiber direction arrangement and layer composition of hybrid bamboo laminate boards on the physical and mechanical properties. The raw material used was tali bamboo ( Gigantochloa apus (J.A. Schultes) Kurs) rope in the form of flat sheets (zephyr) and falcata veneer ( Paraserianthes falcataria (L) Nielsen). Zephyr bamboo was arranged in three layers using water-based isocyanate polymer (WBPI) with a glue spread rate of 300 g/m 2 . There were variations in the substitution of the core layer with falcata veneers (hybrid) as much as two layers and using a glue spread rate of 170 g/m 2 . The laminated bamboo board was cold-pressed at a pressure of 22.2 kgf/cm 2 for 1 h, and the physical and mechanical properties were evaluated. The results showed that the arrangement of the fiber direction significantly affected the dimensional stability, modulus of rupture, modulus of elasticity, shear strength, and screw withdrawal strength. However, the composition of the layers had no significant effect on the physical and mechanical properties. The bonding quality of bamboo laminate boards with WBPI was considered to be quite good, as shown by the absence of delamination in all test samples. The bamboo hybrid laminate board can be an alternative based on the physical and mechanical properties that can meet laminated board standards.","PeriodicalId":17357,"journal":{"name":"Journal of the Korean wood science and technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70827932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-01DOI: 10.5658/wood.2022.50.2.126
E. Jang
In this study, I used wood pellets as an eco-friendly sound-absorbing material. The aim of the research was to analyze the effect of the filling height of wood pellets on sound absorption. This was done using two types of wood pellets of different lengths (A group: 1.5–3 cm, B group: less than 1.5 cm). With increasing filling height of the wood pellets, the optimum sound absorption shifted towards a lower frequency. The group B wood pellets had better sound absorption capacity than the group A ones. The optimum sound absorption coefficient of group A filled to a height of 7 cm was 0.722 at 864 Hz. On the other hand, that of group B filled to a height of 7 cm was 0.764 at 862 Hz, 5.82% higher than that of group A. While wood pellets are used as an eco-friendly fuel, the results of this study suggest the possibility of using wood pellets as an eco-friendly sound-absorbing material.
{"title":"Experimental Investigation of the Sound Absorption Capability of Wood Pellets as an Eco-Friendly Material","authors":"E. Jang","doi":"10.5658/wood.2022.50.2.126","DOIUrl":"https://doi.org/10.5658/wood.2022.50.2.126","url":null,"abstract":"In this study, I used wood pellets as an eco-friendly sound-absorbing material. The aim of the research was to analyze the effect of the filling height of wood pellets on sound absorption. This was done using two types of wood pellets of different lengths (A group: 1.5–3 cm, B group: less than 1.5 cm). With increasing filling height of the wood pellets, the optimum sound absorption shifted towards a lower frequency. The group B wood pellets had better sound absorption capacity than the group A ones. The optimum sound absorption coefficient of group A filled to a height of 7 cm was 0.722 at 864 Hz. On the other hand, that of group B filled to a height of 7 cm was 0.764 at 862 Hz, 5.82% higher than that of group A. While wood pellets are used as an eco-friendly fuel, the results of this study suggest the possibility of using wood pellets as an eco-friendly sound-absorbing material.","PeriodicalId":17357,"journal":{"name":"Journal of the Korean wood science and technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45063876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-01DOI: 10.5658/wood.2022.50.2.113
Ley-Fleury ELLA NKOGO, C. S. A. BOPENGA BOPENGA, Franck-Estime Ngohang, L. Mengome, Sophie Aboughe Angone, P. Edou Engonga
This study aimed to explore the biodiversity of chemical compounds found in the bark of Guibourtia tessmannii from Gabon, commonly called Kévazingo, and evaluate their anti-termite activity to determine their potential values as a source of development of anti-termite products that can be valued in the fields of fine chemicals and wood preservation. Extraction of G. tessmannii bark powders was carried out using the cold maceration method with trichloroethylene, acetone, ethanol, and water. Phytochemical screening made it possible to highlight groups of chemical families present in the extracts. Anti-termite activity was tested on the wild termites “Cubitermes sp” of the genus Isoptera. The yield of the extracts were 17.11% for the buttress and 13.42% for the height at 6 m. Phytochemical tests revealed that alkaloids, polyphenols, sterols, tannins, reducing compounds, flavonoids, saponins, and anthraquinones were present in the extracts. Results of anti-termite activity indicated that anti-termite activity varied with the different parts of the bark studied, extraction solvent, and concentration (50/50) and (25/75) of the extracts used. The extracts at 50/50 concentration showed a slightly better anti-termite activity compared to the 25/75 concentration. In addition, the buttress Kévazingo or buttress showed the strongest anti-termite activity for the aqueous extract with a survival rate of 0% after 2 days.
{"title":"Phytochemical and Anti-Termite Efficiency Study of Guibourtia tessmanii (harms) J. Léonard (Kévazingo) Bark Extracts from Gabon","authors":"Ley-Fleury ELLA NKOGO, C. S. A. BOPENGA BOPENGA, Franck-Estime Ngohang, L. Mengome, Sophie Aboughe Angone, P. Edou Engonga","doi":"10.5658/wood.2022.50.2.113","DOIUrl":"https://doi.org/10.5658/wood.2022.50.2.113","url":null,"abstract":"This study aimed to explore the biodiversity of chemical compounds found in the bark of Guibourtia tessmannii from Gabon, commonly called Kévazingo, and evaluate their anti-termite activity to determine their potential values as a source of development of anti-termite products that can be valued in the fields of fine chemicals and wood preservation. Extraction of G. tessmannii bark powders was carried out using the cold maceration method with trichloroethylene, acetone, ethanol, and water. Phytochemical screening made it possible to highlight groups of chemical families present in the extracts. Anti-termite activity was tested on the wild termites “Cubitermes sp” of the genus Isoptera. The yield of the extracts were 17.11% for the buttress and 13.42% for the height at 6 m. Phytochemical tests revealed that alkaloids, polyphenols, sterols, tannins, reducing compounds, flavonoids, saponins, and anthraquinones were present in the extracts. Results of anti-termite activity indicated that anti-termite activity varied with the different parts of the bark studied, extraction solvent, and concentration (50/50) and (25/75) of the extracts used. The extracts at 50/50 concentration showed a slightly better anti-termite activity compared to the 25/75 concentration. In addition, the buttress Kévazingo or buttress showed the strongest anti-termite activity for the aqueous extract with a survival rate of 0% after 2 days.","PeriodicalId":17357,"journal":{"name":"Journal of the Korean wood science and technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48747859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-01DOI: 10.5658/wood.2022.50.2.81
Kwang-Hee Lee, S. Jo, S. Kim
To analyze the relationship between climatic factors (mean monthly temperature and total precipitation) and tree-ring growths of Pinus densiflora S. et Z. from National Parks (according to region) of the Korea, 20 trees were sampled from 13 National Parks. Only trees that were successfully cross-dated were used for dendrochronological analysis, and at least 11 trees were included. The tree-ring chronology of Mt. Bukhan (covering the shortest period of 1917–2016 [100 years]) was assessed, as well as that of Mt. Seorak (covering the longest period of 1687–2017 [331 years]). After cross-dating, each ring width series was doublestandardized by first fitting a logarithmic curve and then a 50-year cubic spline. The relationships between climate and tree-ring growth were calculated with response function analysis. The results show a significant positive correlation between a given year’s February-March temperature, May precipitation levels, and tree-ring growth. It indicates that a higher temperature in early spring and precipitation before cambium activity are important for radial growths of Pinus densiflora in the Korea.
{"title":"The Relationship between Tree-Ring Growth in Pinus densiflora S. et Z. and the Corresponding Climatic Factors in Korea","authors":"Kwang-Hee Lee, S. Jo, S. Kim","doi":"10.5658/wood.2022.50.2.81","DOIUrl":"https://doi.org/10.5658/wood.2022.50.2.81","url":null,"abstract":"To analyze the relationship between climatic factors (mean monthly temperature and total precipitation) and tree-ring growths of Pinus densiflora S. et Z. from National Parks (according to region) of the Korea, 20 trees were sampled from 13 National Parks. Only trees that were successfully cross-dated were used for dendrochronological analysis, and at least 11 trees were included. The tree-ring chronology of Mt. Bukhan (covering the shortest period of 1917–2016 [100 years]) was assessed, as well as that of Mt. Seorak (covering the longest period of 1687–2017 [331 years]). After cross-dating, each ring width series was doublestandardized by first fitting a logarithmic curve and then a 50-year cubic spline. The relationships between climate and tree-ring growth were calculated with response function analysis. The results show a significant positive correlation between a given year’s February-March temperature, May precipitation levels, and tree-ring growth. It indicates that a higher temperature in early spring and precipitation before cambium activity are important for radial growths of Pinus densiflora in the Korea.","PeriodicalId":17357,"journal":{"name":"Journal of the Korean wood science and technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43037241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.5658/wood.2022.50.1.68
Jian Liu, Y. Ji, Jianshou Lu, Z. Li
Timber boardwalk decks are widely installed in parks and scenic areas to provide pedestrians an elevated footpath as well as harmony with the surrounding natural scene. In order to extend the lifespan of boardwalks in the outdoor environment, industrially treated pine timber, such as Pinus sylvestris, is often adopted. However, accidents of pedestrians injured by damaged boardwalk decks have been constantly reported. Therefore, the mechanical behavior of two different types of treated timber was examined in this study under repeated wetting and drying. An increasing number of radial cracks appeared with increasing length and width as more cycles were performed. A loss of more than 40% of the screw withdrawal capacity was observed in both end grain and face grain for the two types of timber after twelve accelerated wet-dry cycles, which coincides with the observation of damaged timber boardwalks in the field investigation. At the same time, it was found that both the compressive and the flexural strength was not sensitive to the wet-dry cycles especially at large cycle numbers.
{"title":"Mechanical Behavior of Treated Timber Boardwalk Decks under Cyclic Moisture Changes","authors":"Jian Liu, Y. Ji, Jianshou Lu, Z. Li","doi":"10.5658/wood.2022.50.1.68","DOIUrl":"https://doi.org/10.5658/wood.2022.50.1.68","url":null,"abstract":"Timber boardwalk decks are widely installed in parks and scenic areas to provide pedestrians an elevated footpath as well as harmony with the surrounding natural scene. In order to extend the lifespan of boardwalks in the outdoor environment, industrially treated pine timber, such as Pinus sylvestris, is often adopted. However, accidents of pedestrians injured by damaged boardwalk decks have been constantly reported. Therefore, the mechanical behavior of two different types of treated timber was examined in this study under repeated wetting and drying. An increasing number of radial cracks appeared with increasing length and width as more cycles were performed. A loss of more than 40% of the screw withdrawal capacity was observed in both end grain and face grain for the two types of timber after twelve accelerated wet-dry cycles, which coincides with the observation of damaged timber boardwalks in the field investigation. At the same time, it was found that both the compressive and the flexural strength was not sensitive to the wet-dry cycles especially at large cycle numbers.","PeriodicalId":17357,"journal":{"name":"Journal of the Korean wood science and technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42686089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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