Weathering Properties of Paulownia tomentosa and Pinus koraiensis Woods Heat-Treated in Palm Oil and Air

( Intan Fajar Suri ),( Byantara Darsan Purusatama ),( Jong Ho Kim ),( Go Un Yang ),( Denny Prasetia ),( Muhammad Alvin Savero ),( Se Yeong Park ),( Nam Hun Kim ) 한국목재공학회 2022 한국목재공학회 학술발표논문집 Vol.2022 No.1

This study aimed to evaluate the weathering properties of Paulownia tomentosa and Pinus koraiensis woods heat-treated in palm oil (OHT) and air (AHT) at 180℃, 200℃, and 220℃ for 2 hours. The untreated and heat-treated samples were exposed to UV and water for artificial weathering test according to ASTM G53-96. The artificial weathering test of heat-treated and untreated wood samples was performed by exposing to UV lamps in the QUV accelerated weathering tester (QUV/se Accelerated Weathering Tester, Q-LAB, USA) for 168 h and 336 h. The weathering cycle involved a continuous light irradiation of UV exposure for 2 hours and condensation for 2 hours. Color change and dimensional stability of the weathered samples were determined. Color change was measured by the CIEL*a*b* system (Esteves et al. 2008). Macroscopically, there was hardly shown on color difference in the wood samples before and after weathering. After weathering test, heat-treated wood of both species showed lower total color change than the control samples, and the total color change decreased with increasing treatment temperature. The total color change of OHT wood was smaller than that of AHT wood samples. In both species, the heat-treated wood samples showed higher dimensional stability than the control samples. The volumetric shrinkage of heat-treated wood samples decreased as the temperature increased. The OHT wood samples showed smallest volumetric shrinkage than AHT wood samples. In conclusion, after the weathering test, the OHT wood samples displayed better color and dimensional stability than the AHT wood samples.

Color Properties of Paulownia tomentosa and Pinus koraiensis Woods after Oil Heat Treatment and Air Heat Treatment

( Intan Fajar Suri ),( Byantara Darsan Purusatama ),( Jong Ho Kim ),( Go Un Yang ),( Denni Prasetia ),( Nam Hun Kim ) 한국목재공학회 2021 한국목재공학회 학술발표논문집 Vol.2021 No.1

This study aimed to determine and compare the wood discoloration of Paulownia tomentosa and Pinus koraiensis woods after oil heat treatment and air heat treatment to provide valuable information for further utilization of these species. The discoloration of heat treated wood was determined by the CIE-Lab color system. Oil and air heat treatment was carried out at temperatures of 180, 200, and 220℃ for 1, 2, and 3 hours. Lightness (L*) in both heat treatments decreased with increasing temperature and duration. Oil heat treated samples showed a higher reduction in L* value than samples treated with air heat. The great extent of L* change is showed in Paulownia tomentosa. The red/green (a*) chromaticity in both woods increased at 180 and 200℃ and remained nearly the same at 220℃. The yellow/blue chromaticity (b*) in both wood samples treated in hot oil and hot air increased at 180℃, but decreased greatly with increasing duration at 200 and 220℃. Overall color change (ΔE*) in oil heat treatment and air heat treatment increased with increasing temperature, indicating higher values for Paulownia tomentosa compared to Pinus koraiensis. In conclusion, it was revealed that there were several differences in the effect of heat treatment methods on the color change between the two types of wood. Oil heat treatment can reduce processing time and is a more effective method than air heat treatment for improving wood color using low temperatures.

Physical and mechanical properties of oil and air heat-treated Paulownia tomentosa and Pinus koraiensis Woods

Intan Fajar Suri,Byantara Darsan Purusatama,Denni Prasetia,Jong Ho Kim,Wahyu Hidayat,Nam Hun Kim 강원대학교 산림과학연구소 2022 강원대학교 산림과학연구소 학술대회 Vol.2022 No.10

The effects of oil and air heat treatment on the physical and mechanical properties of Paulownia tomentosa and Pinus koraiensis woods were determined and compared. Heat treatments were conducted at 180, 200, and 220 °C for 1, 2, and 3 hours. Changes in properties of heat-treated woods including color, weight, density, volume shrinkage, abrasion, compressive strength, and hardness were investigated. The oil heat-treated specimens showed a darker color than the air heat-treated specimens. In oil heat treatment, the weight and density increased significantly, but in air heat treatment, the weight and density decreased slightly. The volume shrinkage by oil heat treatment exhibited lower compared to that by air heat treatment. The oil heat-treated samples showed lower weight loss in abrasion than air heat-treated samples. Compressive strength increased by oil heat treatment at all temperatures, in contrast, the compression strength of the air heat-treated samples increased at 180 and 200 °C and rapidly decreased at 220 °C. The hardness of oil heat-treated Pinus koraiensis wood increased, but vice versa in Paulownia tomentosa wood. In air heat treatment, both wood species showed a decrease in hardness.

Properties of Heat-Treated Paulownia tomentosa and Pinus koraiensis Woods in Oil and Air

( Intan Fajar Suri ),( Byantara Darsan Purusatama ),( Jong Ho Kim ),( Go Un Yang ),( Denni Prasetia ),( Nam Hun Kim ) 한국목재공학회 2021 한국목재공학회 학술발표논문집 Vol.2021 No.1

The objective of this study was to determine and compare the effects of the heat treatment in oil and air on the physical and mechanical properties of Paulownia tomentosa and Pinus koraiensis woods. The heat treatment in both oil and air was conducted at 180, 200, and 220℃ for 1, 2, and 3 hours. The characteristic change of the heat-treated woods, such as weight, density, volume shrinkage, compression strength, and hardness, was determined. Heat treatment in oil also caused a considerable increase in weight and density, but the weight and density of air heat-treated wood decreased slightly. Oil heat treatment exhibited lower volume shrinkage compared to air heat treatment. Compressive strength increased by oil heat treatment at all temperatures, while in air heat treatment the compression strength increased at 180 and 200℃ and rapidly decreased at 220℃. The hardness of oil heat-treated Pinus koraiensis wood increased, but vice versa in Paulownia tomentosa woods. In air heat treatment, both wood species showed a decrease in hardness. In conclusion, it is revealed that there were some differences in the effect of physical and mechanical properties caused by heat treatment methods between both wood species and that oil heat treatment is more effective method to improve some properties compare to air heat treatment.

Properties of Gmelina arborea and Melia azedarach Woods after Oil-Heat Treatment

( Intan Fajar Suri ),( Byantara Darsan Purusatama ),( Jong Ho Kim ),( Jae Ik Jo ),( Seong Hyun Kim ),( Do Hoon Kim ),( Wahyu Hidayat ),( Fauzi Febrianto ),( Nam-hun Kim ) 한국목재공학회 2020 한국목재공학회 학술발표논문집 Vol.2020 No.1

The objective of the study was to evaluate the effect of oil-heat treatment on the anatomical, physical, and chemical properties of gmelina (Gmelina arborea) and mindi (Melia azedarach) wood. Oil-heat treatment was conducted at 180°C, 200°C, and 220°C. Anatomical characteristics, such as the dimension of vessel and fiber was observed by scanning electron microscopy. The results showed that vessel lumen area and vessel diameter in radial and tangential direction of both gmelina and mindi increased with increasing temperature. The lumen areas of fibers and total are of fibers in both woods were decreased by oil-heat treatment, and the wall area of fiber increased with increasing temperature. Weight change, density, and dimensional swelling were also measured. Both woods tended to gain weight after heat treatment at 180°C and 200°C, and then lose weight after heat treatment at 220°C. The density of mindi increased at 180°C and 200°C and decreased slightly at 220°C. However, the density of gmelina seems did not change after the treatment. Dimensions of the specimens in the tangential direction increased by heat treatment, but the rate decreased with increasing temperature. Consequently, it was revealed that the oil-heat treatment affected to change anatomical and physical properties of gmelina and mindi woods.

Physical and mechanical properties of oil and air heat-treated Paulownia tomentosa and Pinus koraiensis woods

Intan Fajar Suri,Byantara Darsan Purusatama,Jong Ho Kim,Go Un Yang,Denni Prasetia,Wahyu Hidayat,Fauzi Febrianto,Nam Hun Kim 강원대학교 산림과학연구소 2021 강원대학교 산림과학연구소 학술대회 Vol.2021 No.10

The objective of the study was to determine and compare the effects of the different heat treatment media on the physical and mechanical properties of Paulownia tomentosa and Pinus koraiensis woods. Heat treatment was conducted in oil and air at 180, 200, and 220°C for 1, 2, and 3 hours. The properties of the heat-treated woods including color, weight, density, volume shrinkage, compression strength, and hardness, were investigated. Oil heat-treated wood exhibited a darker color than the air heat-treated wood. Weight and density of oil heat-treated wood showed a remarkable increase, but those of air heat-treated wood slightly decreased. Oil heat-treated wood exhibited lower volume shrinkage compared to air heat-treated wood. Axial compressive strength increased by oil heat treatment at all temperatures, while in air heat treatment the axial compressive strength increased at 180 and 200°C and decreased at 220°C. The hardness of oil heat-treated Pinus koraiensis wood increased, in contrast with Paulownia tomentosa wood. In air heat treatment, both wood species showed a decrease in hardness. In conclusion, there were some differences in the effect of the heat treatment media on the physical and mechanical properties between the two wood species and heat treatment in oil is more effective method to improve some wood properties than heat treatment in air.

Physical and Mechanical Properties of Agriboard from Agro-Industrial Wastes Bonded with Formaldehyde-Free Natural Rubber Latex Adhesive

Wahyu Hidayat,Nana Aprilliana,Intan Fajar Suri,Muhammad Adly Rahandi Lubis,Sandi Asmara,Sri Hidayati,Samsul Bakri,Apri Heri Iswanto,Nam Hun Kim 강원대학교 산림과학연구소 2022 강원대학교 산림과학연구소 학술대회 Vol.2022 No.10

Indonesia has abundant renewable resources, including agro-industrial residues and wood wastes. Using this biomass as alternative raw materials in particleboard production can potentially respond to the increased global demand for wood-based products. This research was conducted to investigate the properties of particleboard from agro-industrial residues bonded with natural rubber latex (NRL)-based adhesive. Particleboards with the dimension of 40 ´ 40 ´ 1 cm3 and a target density of 0.7 g/cm3 were made using different compositions of agro-industrial residues (cassava stem, sengon wood waste, and rice husk) and NRL adhesive (10%, 15%, and 20%). The physical and mechanical properties were evaluated following the Japanese Industrial Standard A 5908 (2003) standard for particleboard. The results showed no remarkable differences in the physical properties of the PB panel, such as density, moisture content, water absorption, and thickness swelling, with different agro-industrial residues formulations and NRL adhesive content. By contrast, the mechanical properties of the board significantly increased with the increase in adhesive content. The optimum mechanical properties of the particleboard were obtained using 20% NRL adhesive and a composition of 40% cassava stem, 30% sengon wood waste, and 30% rice husk. The results showed that cassava stem waste, sengon powder, and rice husks have the potential to be used as a substitute for wood-based composite products, especially for non-structural applications.

호두나무 가지 내 해부학적 특성의 변이

김종호 ( Jongho Kim ),비안타라다르산푸루사타마 ( Byantara Darsan Purusatama ),인탄파자르수리 ( Intan Fajar Suri ),양고운 ( Goun Yang ),프라세티아데니 ( Prasetia Denni ),김남훈 ( Namhun Kim ) 한국목재공학회 2021 한국목재공학회 학술발표논문집 Vol.2021 No.1

활엽수 가지부에서 발생하는 지지재(supporting wood)의 생장에 따른 해부학적 특성 변이를 조사하고자 호두나무 가지의 조직특성을 관찰하였다. 강원도 춘천에서 채취한 길이 약 57cm, 직경 약 4cm의 호두나무 가지를 공시재료로 활용했으며, 해부학적 특성의 변이를 조사하고자 공시재료를 길이방향으로 4등분하여 지점별 소원판을 제작한 후, 수(pith)를 기준으로 상, 하, 좌, 우 4방향의 영구슬라이드를 제작하여 수심부와 수피부 도관내강의 접선직경, 단위면적(㎟)당 도관의 수량, 단위거리(㎜)당 방사조직의 수량, 방사조직의 높이 등을 측정하고 경향성을 분석했다. 수의 위치는 가지가 분화하는 1번 위치부터 3번 위치까지 상부방향으로 편심하였으나, 4번 위치에서는 가지부의 중앙부에 도달하였으며, 수를 기준으로 상부에서는 인장이상재의 특징 중 하나인 세포벽 내 젤라틴 층이 빈번히 나타났고, 좌, 우측부에서는 일시적으로 나타났으며, 하부에서는 관찰되지 않았다. 도관의 접선방향 직경은 가지재의 생장방향에 따라 미약하게 감소하였으나, 수를 기준으로 한 방향에 따른 분류에서는 경향성이 매우 미비한 증가경향이 나타났으며, 수심부에서 수피부로 이행할수록 증가하는 경향이 나타났다. 단위면적(㎟)당 도관의 수량과 고립관공의 수는 가지재의 생장방향에 따라 소폭 증가하는 경향이 나타났으나, 복합관공의 수는 변화하지 않고 유지되는 경향이 나타났다. 이로 인해 고립관공의 비율은 생장방향으로 이행할수록 증가하고, 복합관공의 비율은 감소하였다. 단위거리(㎜)당 방사조직의 수는 가지재의 생장방향, 수를 기준으로 한 방향에 대해서는 특정 경향성이 확인되지 않았거나 매우 미비하였으나, 수심부에서 수피부로 이행하며 수량이 감소하는 경향이 나타났다. 반면, 방사조직의 높이는 가지재의 생장방향에 따라 미세한 증가경향이 확인되었으나, 증가폭이 크지 않고 일정한 범위를 유지하는 것으로 확인되었다. 본 연구를 통해 인장응력재의 위치가 역전되는 지지재의 특성이 나타나는 호두나무 가지재에서 해부학적 특성 변이의 기초적인 경향성이 확인되었으며, 수의 위치가 목부의 중앙에 위치하더라도 이상재의 특성이 계속해서 나타나는 것으로 관찰되었다. 추후 보다 다양한 수종의 교차검증을 통해 경향성을 검증해 나갈 예정이다.

대나무재 및 목재의 저온탄화 특성

양고운 ( Goun Yang ),김종호 ( Jongho Kim ),비안타라다르산푸루사타마 ( Byantara Darsan Purusatama ),인탄파자르수리 ( Intan Fajar Suri ),프라세티아데니 ( Denni Prasetia ),김남훈 ( Namhun Kim ) 한국목재공학회 2021 한국목재공학회 학술발표논문집 Vol.2021 No.1

본 연구는 대나무재 및 목재의 저온탄화과정 중 열분해 특성을 구명하기 위하여 수행하였다. 공시재료는 인도네시아산 Giant bamboo(Dendrocalamus giganteus), Kuning bamboo(Bambusa vulgaris), Betung bamboo(Dendrocalamus asper), Tali bamboo(Gigantochloa apus), 국내에서 자생하는 Moso bamboo (Phyllostachys pubescens), 소나무(Pinus densiflora) 및 굴참나무(Quercus variabilis)를 사용하였다. 시료의 크기는 10mm(R)X10mm(T)X20mm(L)로서 고온전기탄화로(Supertherm, HT 16/16, Germany)를 이용하여200℃, 240℃, 280℃, 320℃에서 탄화하였다. 각 탄화시료는 60mesh 목분으로 제작하여 발열량 및 공업분석을 실시하였다. 거시적 구조, 중량감소율, 발열량, pH, 셀룰로오스의 결정특성을 조사하였고 함수율, 회분, 휘발분 및 고정탄소 등 공업분석을 실시하였다. 대나무재는 320℃ 탄화 시 가운데 부분의 팽창현상이 나타났고 굴참나무재에서는 할렬이 관찰되었다. 탄화온도가 증가함에 따라 중량감소율, 발열량, pH, 함수율, 회분, 고정탄소 값은 증가하는 경향을 보였고 휘발분은 감소하는 경향을 보였다. 중량감소율 및 발열량 실험에서 대나무재는 200~240℃구간에서 급증한 반면 목재는 240~280℃ 구간에서 급증한 것을 확인하였다. 특히 320℃에서 탄화된 대나무재의 회분율은 3.75%~11.28%였으나 소나무와 굴참나무는 각각 0.67%, 2.84%로 대나무재와 목재간의 차이를 확인하였다.

Softwood Species identification using Convolutional Neural Network

Jong-Ho Kim,Byantara Darsan Purusatama,Prasetia Denni,Alvin Muhammad Savero,Intan Fajar Suri,Seung-Hwan Lee,Nam-Hun Kim 강원대학교 산림과학연구소 2022 강원대학교 산림과학연구소 학술대회 Vol.2022 No.10

In order to improve the accessibility of wood species identification, the four domestic and six imported softwood species were classified using deep learning method. The cross-section micrographs were used as a dataset; which 1,535 images of 40x micrographs with earlywood and latewood, and 2,000 images of 200x micrographs for earlywood and latewood each. The classification accuracy and loss rate of 10 species were compared using the four convolutional neural network models such as modified CNN, GoogLeNet, VGG16, and ResNet. In verifying the classification accuracy and loss rate by model, the influencing factors, such as epochs, collected part of the dataset, and dataset augmentation, were analyzed. The modified CNN and GoogLeNet models increased classification accuracy in proportion to the number of epochs, achieving more than 95% classification accuracy in the final stage. At the same time, the loss rate decreased with decreasing the number of epochs. VGG16 model showed a low classification accuracy of 20~30% and a high loss rate regardless of the number of epochs during learning under the same conditions as the other models. The ResNet model showed a high classification accuracy of over 90%, with a low loss rate during the training process. However, classification accuracy decreased to 20~30%, with a high loss rate when the test process. As a result of analyzing the general trends in the four models, the classification accuracy increased with increasing the number of epochs in the latewood and total dataset. In contrast, the earlywood dataset didn't show any tendency. The dataset augmentation was not significantly correlated with the classification accuracy and loss rate. Based on these results, modified CNN and GoogLeNet models among the four deep learning models showed excellent wood species classification performance. Further, it is expected that the two models can be applied to identify unknown ten softwood species.