Fire-resistant performance of a laminated veneer lumber joint with metal plate connectors protected with graphite phenolic sphere sheeting     

Bambang Subyakto  Toshimitsu Hata  Isamu Ide  Shuichi Kawai 《Journal of Wood Science》2001,47(3):199-207

Creep under fire of laminated veneer lumber (LVL) joined with metal connectors was studied. The fire-resistant performance of LVL butt joints connected with metal plates protected with graphite phenolic sphere (GPS) sheeting was discussed. The GPS sheeting was overlaid on the joint in different sizes and locations. The joint was exposed to a burner with a top flame temperature of 800°C and loaded with a load of 200 N to test for creep under fire. The results showed that the fire-resistant performance of the joint was markedly improved by the sheeting. The size and location of the GPS sheet significantly affected the time to rupture of the specimen, which was six times longer than that without GPS. Temperature measurements at the joint showed that the GPS sheeting distributed the heat along the surface and delayed failure. Thermographic images and analyses clarified the improvement in fire-resistant properties due to GPS.  相似文献   

Effects of high temperature kiln drying on the practical performances of Japanese cedar wood (Cryptomeria japonica) I: changes in hygroscopicity due to heating     

Eiichi Obataya  Sakae Shibutani  Kensuke Hanata  Shuichi Doi 《Journal of Wood Science》2006,52(1):33-38

The effect of heating on the hygroscopicity of Japanese cedar wood was investigated as a simple evaluation of thermal degradation in large-dimension timber being kiln-dried at high temperatures (>100°C). Small wood pieces were heated at 120°C in the absence of moisture (dry heating) and steamed at 60°, 90°, and 120°C with saturated water vapor over 2 weeks, and their equilibrium moisture contents (M) at 20°C and 60% relative humidity (RH) were compared with those of unheated samples. No significant change was induced by steaming at 60°C, while heating above 90°C caused loss in weight (WL) and reduction in M of wood. The effects of steaming were greater than those of dry heating at the same heating temperature. After extraction in water, the steamed wood showed additional WL and slight increase in M because of the loss of water-soluble decomposition residue. The M of heated wood decreased with increasing WL, and such a correlation became clearer after the extraction in water. On the basis of experimental correlation, the WL of local parts in large-dimension kiln-dried timber was evaluated from their M values. The results indicated that the thermal degradation of inner parts was greater than that of outer parts.  相似文献   

Changes of decay and termite durabilities of Japanese larch (Larix leptolepis) wood due to high-temperature kiln drying processes     

Shuichi Doi  Masakazu Aoyama  Shigeru Yamauchi  Yasuji Kurimoto 《Journal of Wood Science》2005,51(5):526-530

We investigated the effects of high-temperature drying schedules (120°–130°C) on decay and termite feeding of Japanese larch timbers. Thermogravimetric analysis was conducted to investigate changes of the wood components. Decay and termite feeding tests showed that specimens dried under high-temperature schedules were susceptible against a decaying fungus Fomitopsis palustris and attacks from termites Coptotermes formosanus and Reticulitermes speratus. These drying schedules changed chemical components, which were suggested by the thermal analytical result compared to the control sample. The results of this study indicated that the acceleration of termite feeding takes place even under temperatures that are comparatively lower than that used in our previous research in which 170°C steaming treatment was applied to Japanese larch wood. Decay durability against a brown rot fungus also decreased, possibly from production of low molecular weight fragments when hemicellulose decreased during the high-temperature drying processes.  相似文献   

Fire protection of a laminated veneer lumber joint by wood carbon phenolic spheres sheeting     

Subyakto  Toshimitsu?Hata  Isamu?Ide  Takeshi?Yamane  Shuichi?KawaiEmail author 《Journal of Wood Science》2004,50(2):157-161

Laminated veneer lumber joints made with metal plate connectors were protected with wood carbon phenolic spheres (CPS) sheeting and tested for creep under fire. The effects of the carbonizing temperature of charcoal, used as raw material for the CPS sheets, the thickness, and the location of the sheet on the joint regarding the fire-resistance performance of the joint were studied. The time to rupture of the joints covered with CPS sheets made from charcoal carbonized at 800°C (CPS800) was slightly prolonged compared with that of uncovered joints. On the other hand, the time to rupture of CPS sheets made from charcoal carbonized at 1600°C (CPS1600) was markedly extended. The changes in the charcoal properties due to increasing the carbonizing temperature might be the main reason the CPS1600 sheets had higher fire-resistance performance. The thickness and location of CPS1600 sheets have significant effects on the fire resistance of the joint. A highly fire-resistant laminated veneer lumber joint was obtained using a CPS1600 sheet. The CPS1600 sheet with a thickness of 3mm covering three sides of the joint prolonged the time to rupture 16-fold compared with that of unprotected joints.Part of this paper was presented at the 4th International Wood Science Symposium, Serpong, Indonesia, September 2002  相似文献   

The critical stress in various stress levels of bending member on fire exposure for mechanical graded lumber     

Anita?Firmanti  Bambang?Subiyanto  Shinjiro?Takino  Shuichi?KawaiEmail author 《Journal of Wood Science》2004,50(5):385-390

This study focused on the relationship between stress level and the fire resistance of structural lumber. The 210 samples were prepared from 15-year-old trees of Acacia mangium from the Forest Estate Plantation, Indonesia. Specimens were 20 ® × 20 (T) × 500mm (L) and were air-dried. Sixty samples were tested under four-point bending stress to obtain the modulus of elasticity (MOE) and the modulus of rupture (MOR) for classifying the stress grades of the remaining 150 samples. The tests were performed using a four-point load bending position at various stress level while the specimens were exposed to fire along the shear-free region. Time to failure was affected by the stress levels in an exponential trend. Despite changes in stress level, charring rate, and time to failure, the critical stress of a member from the same species was similar. The fire performance under applied load could be predicted by using simplified fire-testing methods. The developed testing apparatus is valid for evaluating the small-scale fire resistant behavior of structural lumber in bending.  相似文献   

Bone morphological analyses in Spontaneously Diabetic Torii (SDT) fatty rats     

Takeshi OHTA  Shuichi KIMURA  Masaya HIRATA  Takahisa YAMADA  Toshie SUGIYAMA 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2015,77(10):1327-1330

The Spontaneously Diabetic Torii (SDT) fatty rat, a model for obese type 2 diabetes, shows bone quantitative abnormalities, namely low bone mineral density (BMD). The objective of this study was to evaluate bone morphological changes, in particular identifying the bone qualitative abnormalities, in the SDT fatty rat. Male SDT fatty rats showed increases in total trabecular area and trabecular number and decreases in trabecular thickness in cancellous bones of the proximal tibia, indicating trabecular miniaturization. The SDT fatty rat is useful for investigation of pathophysiological changes in bone quality in diabetic osteoporosis.  相似文献   

Investigation of a new natural adhesive composed of citric acid and sucrose for particleboard II: effects of board density and pressing temperature     

Kenji Umemura  Osamu Sugihara  Shuichi Kawai 《Journal of Wood Science》2015,61(1):40-44

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Development of 18 microsatellite markers in Pieris japonica,a poisonous tree insulated from the browsing pressure of herbivores,using a next-generation sequencer     

Hiroyuki Kurokochi  Engkong Tan  Shuichi Asakawa  Chunlan Lian 《Journal of Forest Research》2015,20(1):244-247

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Stocking effectiveness of hatchery-released kuruma prawns estimated by two-stage sampling of commercial catch in Ariake Sound, Japan     

Tadanori Yamaguchi  Shiro Ito  Katsuyuki Hamasaki  Shuichi Kitada 《Fisheries Science》2006,72(2):233-238

ABSTRACT:    To evaluate the stocking effectiveness of the kuruma prawn Penaeus japonicus , a two-stage sampling survey of Gensiki bottom-drift-netters was carried out in Ariake Sound, Saga Prefecture, Japan. A total of 471 000 hatchery-produced juveniles, marked by cutting off the right uropods, was released. Thirty-three fishing days were randomly drawn from four boats, which were selected from the 80 boats operating in the fishery. All prawns caught on the selected days were examined, and the hatchery-produced individuals were identified by their regenerated uropods. A telephone survey of all boats was also conducted, to determine the number of fishing days. A total of 286 marked prawns were caught on the survey days for the Saga area in Ariake Sound, from the last half of July to the first half of September 2002. The recapture rate and standard error were estimated at 0.76 ± 0.52%. Economic efficiency was estimated at 0.28 ± 0.02. Strategies for sampling schemes and stock recovery are also discussed.  相似文献   

Short Paper     

Chutima Khomvilai  Shuichi Karita  Masaaki Kashiwagi  Motoi Yoshioka 《Fisheries Science》2005,71(5):1188-1190

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