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NOBORU FUJIMOTO Last modified date:2021.06.30

Associate Professor / Sustainable Bioresources Science
Department of Agro-environmental Sciences
Faculty of Agriculture


Graduate School
Undergraduate School


Homepage
https://kyushu-u.pure.elsevier.com/en/persons/noboru-fujimoto
 Reseacher Profiling Tool Kyushu University Pure
http://ffpsc.agr.kyushu-u.ac.jp/tech/
Activity of laboratory
Introduction of member in loboratory .
Academic Degree
Doctor of Philosophy (Agriculture)
Country of degree conferring institution (Overseas)
No
Field of Specialization
Wood material technology
Total Priod of education and research career in the foreign country
00years00months
Research
Research Interests
  • Effective drying of unused wood discs .
    keyword : sugi disc drying
    2016.04~2018.03Development of drying method by micro wave heating for sugi logs..
  • Effective utilizations of unused banboo and hardwoods .
    keyword : Banboo Hardwood
    2007.04Development of drying method by micro wave heating for sugi logs..
  • Development of drying method by micro wave heating for sugi logs.
    keyword : Sugi, Drying logs, Microwave heating
    2000.04~2004.12Development of drying method by micro wave heating for sugi logs..
  • Development of drying methods for heavy timber without checks.
    keyword : drying methods , heavy timber , checks
    1995.04Development of drying methods for heavy timber without checks..
Academic Activities
Papers
1. Andi Hermawan, Noboru Fujimoto, Viscoelastic creep behavior of surface- and inner-layers of sugi boxed-heart timber under various temperatures, Journal of Wood Science, 10.1186/s10086-019-1836-y, 65, 1, 2019.12, This study was conducted to investigate the rheological behavior of sugi boxed-heart timber under constant moisture content (MC) using a cantilever creep test. The focus of the study was the effect of temperature on viscoelastic creep behavior of surface- and inner-layer specimens of the timber. The specimens with dimensions of 75 mm in length, 25 mm wide, and 3 mm thick were prepared. A cantilever creep test with an effective span of 40 mm was conducted under a constant temperature of 20, 65, 80, and 95 °C. The equilibrium moisture content (EMC) of the specimens was set to around 12% at each temperature. A load representing 20% of rupture load of the specimens at each temperature was applied to their free-end and strain gauges were bonded at the fourth span (10 mm) on the upper and bottom surfaces of the specimens. Loading and unloading duration were set for 300 and 180 min, respectively, and a four-element Burgers model was used to model the creep behavior of the timber. It was found that temperature had significant effects on the creep properties of the timber. The surface strain and creep compliance of the surface- and inner-layer specimens tended to increase as the temperature increased. Creep compliance of the surface-layer specimen was higher than that of the inner-layer specimen at each temperature. Fitting the experimental data with the Burgers model used in this study shows good agreement and it was found that elastic (instantaneous) and viscoelastic (delayed) creep compliance of all the specimens tended to increase as the temperature increased. On the other hand, the viscosity of the dashpot element of both the Maxwell and the Kelvin unit tended to decrease as the temperature increased. Although different in magnitude, the creep-recovery compliance parameters had the same tendency as the creep compliance parameters..
2. Andi Hermawan, Toru Nakahara, Hiroki Sakagami, Noboru Fujimoto, Kiyotaka Uchikura, Performance of Sugi lamina impregnated with low-molecular weight phenolic resin, Journal of Wood Science, 10.1007/s10086-013-1338-2, 59, 4, 299-306, 2013.08, 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..
3. Andi Hermawan, Noboru Fujimoto, Hiroki Sakagami, A Study of Vacuum-Drying Characteristics of Sugi Boxed-Heart Timber, Drying Technology, 10.1080/07373937.2012.749274, 31, 5, 587-594, 2013.04, 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..
4. Andi Hermawan, Noboru Fujimoto, Hiroki Sakagami, Effects of High-Temperature and Low-Humidity Pretreatment on the Drying Properties of Sugi Boxed-Heart Timber with Black-Colored Heartwood, Drying Technology, 10.1080/07373937.2012.663433, 30, 7, 780-786, 2012.06, 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..
5. Jinji Piao, Noboru Fujimoto, Yasushi Yamamoto, Soji Nagata, Hybrid kiln drying system with radio frequency heating for hinoki boxed-heart timber with round edges, Journal of the Faculty of Agriculture, Kyushu University, 53, 2, 505-509, 2008.10, To avoid the formation of checks during the drying of hinoki (Chamaecyparis obtusa Endl.) boxedheart timber with round edges, a comparative investigation on the kiln drying and the hybrid drying, the high temperature and low humidity (HT/LH) treatment stage combined with radio frequency (RF) heating, was carried out in this study. The results showed that the hybrid drying could effectively prevent the occurrence of both surface checks and internal checks in the hinoki boxed-heart timber with round edges. Moreover, the hybrid drying time was significantly shortened to 15 hours. The combination of RF heating at the stage of HT/LH treatment resulted in at least following beneficial consequences: reduction of the surface temperature decreasing, attenuation of the tensile stress, promotion of the internal drying, relaxation of the moisture gradient, and inhibition on the extreme drying stress. Therefore, a wood drying strategy with high speed, free of both surface and internal checks could be realized through hybrid drying..
6. Y. Katagiri, Noboru Fujimoto, Y. Murase, Effect of the treatment temperature on the surface drying set of sugi boxed-heart square timber, Drying Technology, 10.1080/07373930601184080, 25, 3, 507-510, 2007.03, High-temperature and controlled humidity treatment before drying has proven to be highly effective in preventing surface checks by forming drying sets in the surface layer of boxed-heart square timber in Japan. In this study, we examined the differences of the surface drying sets on sugi timber under different treatment temperatures. As a result, the width of a surface check after drying was much smaller at a treatment temperature of 120°C than at 80°C, and this indicates that the drying set with 120°C treatment would be larger than that with 80°C treatment. Also we observed that treatment temperature had a greater effect on the drying set as the drying advanced..
7. Jinji Piao, Noboru Fujimoto, Yasushi Yamamoto, Soji Nagata, Development of hybrid kiln drying system with radio frequency heating for the sugi boxed heart timber, Journal of the Faculty of Agriculture, Kyushu University, 52, 1, 117-121, 2007.02, In this study, proper applied stage of the radio-frequency (RF) heating during kiln drying based on the quality concerning the surface checks of the boxed heart timbers was examined. At the stage of the RF heating the moisture contents decreased clearly at the internal parts of timbers. The surface stress of the sugi (Cryptomeria japonica D. Don) boxed heart timber changed into the compression stress by the RF heating in any drying stage. The surface checks increased according to the decrease of the moisture content. However, the increase of the area and the width of the surface checks in the Link 3 were comparatively low, and the quality of these boxed heart timbers seemed relatively good. The amount of electric energy of RF heating in the Link 3 was fewer than that in the Link 1, 2..
8. Jinji Piao, Noboru Fujimoto, Kanehiro Oohashi, Mitsuru Tanikawa, Masashi Kitada, Hozumi Sonobe, Yo Ueda, Drying properties of Sugi round timber with microwave heating, Journal of the Faculty of Agriculture, Kyushu University, 51, 2, 345-349, 2006.10, Sugi round timbers injected with preservative are useful for outdoor playing and construction materials. To dry the Sugi round timbers for preservative injection, three drying methods including microwave drying, kiln drying and air drying were compared in this study. Using microwave drying, the timbers were dried within one day, but the other two drying methods required a much longer time. During most of the microwave drying process, the wood temperature appeared to be higher in the inner layer than in the outer layer. As a result, the inner layer moisture contents were significantly reduced by microwave drying, while kiln drying produced almost no decline in the inner layer moisture contents. In addition, although significant surface checks often occurred in timbers dried by kiln drying and air drying, microwave drying caused few surface checks. In contrast, internal checks were only observed in timbers treated by microwave drying. These results suggested that the microwave drying technique can improve the effectiveness of preservative injection in Sugi round timbers..
9. Noboru Fujimoto, Yuusuke Morita, Takeshi Oouchi, Han Chien Lin, Kanehiro Oohashi, Kazuyuki Kondo, Drying of sugi logs with microwave heating, Zairyo/Journal of the Society of Materials Science, Japan, 10.2472/jsms.54.371, 54, 4, 371-376, 2005.04, Sugi logs were dried with the microwave (MW) heating. The temperature and moisture content distributions in the logs were measured during MW heating. And the surface stresses were measured at the same time as released strains on the surfaces. As a result, the temperature in the center layer was higher than that in the outside layer during drying because of rapid temperature decrease for irradiation stop in intermittent heating system of MW. The moisture content in the center layer was relatively low at the end of drying. The surface stress of dried log was compression for the tangential direction related to surface checks. During seasoning after MW drying, the moisture was removed mainly in the surface layer, and the surface stress changed to tensile stress. As a result, the surface checks occurred for all logs after seasoning in about two or three months. Some dried logs had been sawn into the boxed-heart square timbers. Many surface checks appeared on these timbers because of the existence of internal checks of sugi logs, which occurred by the MW drying. These check widths did not change largely for the efficiently dried timbers as the core part of sugi logs after MW drying..
10. Hisato Oda, Yoshifumi Ebihara, Tadayoshi Sakoda, Noboru Fujimoto, Yasuhide Murase, Variation in Moisture Content of Sugi Boxed Heart Timber in Miyazaki Prefecture during Kiln Drying under High Temperature and Low Humidity II ‡. Distribution and change of moisture content, Mokuzai Gakkaishi/Journal of the Japan Wood Research Society, 10.2488/jwrs.51.227, 51, 4, 227-233, 2005.01, Sugi (Cryptomeria japonica D. Don) boxed heart timbers from Miyazaki prefecture were kiln-dried at low humidity under two high-temperature conditions. The distribution of moisture content, changes in moisture content and the generation of internal checks were examined. Our findings are summarized as follows: 1) In the examination with an intermediate period of steaming, a large difference in moisture content was observed depending on green timber weight. Each layer of timbers of 34 to 36 kg had a moisture content of about 6%, and layers of timber of 37 to 39 kg had a final moisture content ranging from about 6 to 40%. 2) In the examination with a surface-drying stage at a dry-bulb temperature of 75°C and a wet-bulb temperature of 68°C, variation of moisture content in the cross section were almost equalized during the steaming process that followed this stage. 3) The amount of moisture content reduction per hour during drying at a dry-bulb temperature of 120°C was about equal at 1.2 to 1.6% for both drying methods. 4) Internal checks seemed to be generated near moisture content of 30 to 40%..
11. Noboru Fujimoto, K. Tachiwana, K. Oouchi, Y. Mataki, Tension creep of surface layer and compression creep of inner layer perpendicular to the grain in sugi boxed-heart square timber, Zairyo/Journal of the Society of Materials Science, Japan, 10.2472/jsms.50.914, 50, 8, 914-919, 2001.01, Some creep tests were conducted to clarify the effect of temperature on the drying check of sugi (Cryptomeria japonica D. Don) boxed-heart square timbers during kiln drying. The tensile creep behaviors of tangential direction at the outside layer parts of sugi boxed-heart square timbers and the compression creep behaviors of radial direction at the inner parts of them were investigated. Creep strain and residual strain were larger at 80°C than at 40°C under constant moisture content. Under drying condition, these mechano-sorptive creep strains at 80°C and 40°C were almost same. The creep strains increased approximately like a straight line as the moisture content reduced in the area of moisture content less than 30%. Its gradient can be considered that there is no effect of the temperature. But initial elastic deformation at 80°C was larger than at 40°C. As a result, the relative creep in the high temperature showed lower than in the low temperature. After all, it was supposed that the temperature dependence factor for the restraint of surface check of boxed-heart square timber of sugi was elastic characteristic and was not creep characteristic. The value of creep compliance in compression for the radial direction at the part far from the pith showed relatively low during drying..
12. Noboru Fujimoto, Kensuke Goto, Yoshihiro Mataki, Fracture toughness of the surface layer of the boxed-heart square timber of sugi associated with drying check, Zairyo/Journal of the Society of Materials Science, Japan, 10.2472/jsms.48.223, 48, 3, 223-228, 1999.03, Fracture toughness tests were performed on the surface layer of boxed-heart square timber of sugi, after and during drying. Experiments were carried out using of notched tensile specimens with single edge. The critical stress intensity factor (KIc) in the TR system was investigated to clarify effects of drying temperature on resistance against drying surface check of the boxed-heart square timber of sugi. Timbers dried with temperatures of 20 °C and 80 °C had higher resistance against drying check than dried with temperature of 40 °C and 60 °C. AE cumulative events increased slowly at the occurrence state for the tension tests of the specimens dried with temperature of 20 °C and 80 °C, whose KIc values were relatively high. On the other hand, AE cumulative events increased relatively fast for the specimens dried with temperature of 40 °C and 60 °C. Cell-wall break type of micro-fracture occupied the most of fracture in the early wood, when the large amplitude of AE were detected in the early state. Therefore, it was found that the characteristics of AE were closely concerned with KIc values and micro-fracture. The KIc values of the fracture toughness decrease with drying until moisture content of 20%, because of drying stresses. After then, the KIc values increase rapidly with drying under moisture content of 20%. In the drying processes the KIc values have a tendency to be higher with lower drying temperature within this experiment conditions..
13. Noboru Fujimoto, Shuuzou Arita, Yoshihiro Mataki, Changes of dimension and stress in surface layer of sugi dried boxed-heart square timbers with a split liner under cyclic environment, Zairyo/Journal of the Society of Materials Science, Japan, 10.2472/jsms.46.390, 46, 4, 390-394, 1997.01, Dried boxed-heart square timbers of sugi with a split liner were tested for the dimensional stability and tangential stress in surface layer during environmental change. The tests were made under several cyclic conditions of temperature and humidity with reference to the actual day and night condition. The results obtained were as follows ; (1) The change in moisture content with environment was less than 1 % by the oven drying method and less than 4 % by the high frequency moisture meter method. At the same time, the shrinkage chandes of width were less than 0.4 % in the opposite directions for the fluted face and for the other three faces. (2) When the difference of equilibrium moisture content (ΔE.M.C.) between daytime and nighttime was over 4 %, tension stress appeared clearly in the surface layer after changing to the daytime condition. (3) The above daily change in stress behavior depended on the moisture condition of the dried timber. For the insufficient dried timber with a large moisture gradient, the tension stress in surface layer during the daytime condition increased enough to develope into check..