Andi Hermawan
Kyushu University
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Featured researches published by Andi Hermawan.
Drying Technology | 2013
Andi Hermawan; Noboru Fujimoto; Hiroki Sakagami
In this study, we evaluated the effects of drying under atmospheric and vacuum pressure on the drying time, checking, and color change of sugi boxed-heart timber dried at the same dry-bulb temperature and the same wet-bulb depression. The results obtained were as follows: Sugi boxed-heart timber specimens dried at any temperature under vacuum pressure had a shorter drying time than the specimens dried under atmospheric pressure. At moisture content above fiber saturation point and at the same dry-bulb temperature, the specimens dried under vacuum pressure had a drying rate that was almost twice as fast as that of the specimens dried under atmospheric pressure. Sugi boxed-heart timber specimens dried under both atmospheric and vacuum pressure at a higher drying temperature had a shorter drying time than the specimens dried at a lower drying temperature. Apart from the sugi boxed-heart timber specimen dried at a temperature of 100°C under atmospheric pressure, no surface checks were observed for the specimens dried under vacuum pressure or at the other temperatures dried under atmospheric pressure. Slight internal checks were observed in sugi boxed-heart timber specimens dried at a temperature of 100°C under both atmospheric and vacuum pressure. After planer shaving, there was no significant difference between kiln drying under atmospheric pressure and that done under vacuum pressure in terms of the color change (ΔE*) for both sapwood and heartwood of sugi boxed-heart timber specimens.
Drying Technology | 2012
Andi Hermawan; Noboru Fujimoto; Hiroki Sakagami
In this study, the optimal conditions of high-temperature and low-humidity (HT-LH) pretreatment to prevent surface checks of sugi boxed-heart timber with black-colored heartwood were investigated. The focus of this study was on the effects of log diameter, temperature, and pretreatment time on the drying time and checking of the timber dried at a constant temperature and relative humidity. The results obtained were as follows: The drying time of specimens obtained from 22-cm-diameter logs was longer than that obtained from 20-cm-diameter logs. The drying time of specimens obtained from 22-cm-diameter logs was influenced by both pretreatment temperature and time. Higher pretreatment temperature and/or longer pretreatment time resulted in longer drying times. In contrast, in the case of specimens obtained from 20-cm-diameter logs, a longer pretreatment time resulted in a shorter drying time. The average surface check area of specimens tended to decrease and the average total number and length of internal check tended to increase as pretreatment temperature and time increased. Pretreatment at a temperature of 135°C for 10 h or 150°C for 7 h was effective in preventing surface checks of the specimens.
Journal of Wood Science | 2013
Andi Hermawan; Toru Nakahara; Hiroki Sakagami; Noboru Fujimoto; Kiyotaka Uchikura
This study was conducted to evaluate the performance of Sugi lamina impregnated with low-molecular weight phenolic (LMWP) resin using the full cell process followed by curing at high temperature. In this study, penetration of LMWP resin into finger-jointed lamina was examined. Physical and mechanical properties, such as surface hardness, dimensional stability, bending and shear strength of LMWP-resin-treated and untreated lamina were investigated. In addition, the bonding quality and nail-withdrawal resistance of 3-ply assembly specimen made from LMWP-resin-treated and untreated lamina bonded using resorcinol–phenol formaldehyde resin adhesive were also investigated. The main results were as follows: LMWP resin was found to have penetrated sufficiently into finger-jointed lamina. The physical properties of LMWP-resin-treated lamina were found to have improved significantly in comparison with untreated lamina. However, no significant difference was found between LMWP-resin-treated and untreated lamina in terms of their mechanical properties. There was an improvement in bonding quality of the assembly made from LMWP-resin-treated lamina when compared with that made from untreated lamina. In the assembly made from untreated lamina, a significant decrease in nail-withdrawal resistance was observed between dry conditions test and after humidity conditioning test. However, the same tendency was not found in the assembly made from LMWP-resin-treated lamina.
Journal of Wood Science | 2009
Andi Hermawan; Takeshi Ohuchi; Noboru Fujimoto; Yasuhide Murase
The objective of this study was to develop a method for the effective use of both pruned wood and porcelain stone scrap. Thus, we manufactured a wood-porcelain stone composite board, which has excellent waterproof property and incombustibility properties. In addition, we examined the conditions needed to manufacture the wood-porcelain stone composite board as a construction material and evaluated the physical and mechanical properties of this board based on the Japanese Industrial Standard. The main results obtained were as follows: the wood-porcelain stone composite board made from pruned wood and porcelain stone scrap had excellent thickness swelling performance and the board had incombustibility properties that were better than commercial oriented strand board. In both single-layer and three-layer composite boards with weight ratios of porcelain stone particles of 40%, the internal bond strength exceeded the standard value of type 18 particleboard of JIS A 5908. However, the bending properties of the composite board were inferior to the type 18 particleboard standard. Therefore, it will be necessary to improve the bending properties of the board by changing the particle sizes of both the porcelain stone scrap and the pruned wood component.
Resources Conservation and Recycling | 2007
Andi Hermawan; Takeshi Ohuchi; Ryo Tashima; Yasuhide Murase
Journal of The Faculty of Agriculture Kyushu University | 2011
Takeshi Ohuchi; Andi Hermawan; Noboru Fujimoto
Journal of The Faculty of Agriculture Kyushu University | 2010
Andi Hermawan; Takeshi Ohuchi; Noboru Fujimoto
Mokuzai Gakkaishi | 2013
Masakazu Takahashi; Hiroki Sakagami; Noboru Fujimoto; Andi Hermawan
Journal of The Faculty of Agriculture Kyushu University | 2013
Takeshi Ohuchi; Andi Hermawan; Noboru Fujimoto
Materials & Design | 2011
Andi Hermawan; Takeshi Ohuchi; Noboru Fujimoto