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31.
Effect of element type on the internal bond quality of wood-based panels determined by three methods
Three mechanical tests with different loading modes were conducted to evaluate the effect of element type on the internal bond quality of wood-based panels. In addition to the internal bond test, which is commonly used for mat-formed panels, interlaminar and edgewise shear tests were used to test oriented strandboard (OSB), particleboard, medium-density fiberboard (MDF) of two thicknesses, and plywood. The following results were obtained. Epoxy resin proved to be suitable for determining the interlaminar shear modulus instead of hot-melt glue. There was a linear relation between panel density and interlaminar shear modulus and a linear correlation between the interlaminar shear strength and internal bond (IB) strength for the mat-formed panels tested. OSB had the highest edgewise shear modulus, and MDFs had the highest edgewise shear strength in this study. The modulus/strength ratio also depended on both panel type and loading mode. The relation between the shear moduli determined from the edgewise and interlaminar tests indicated the characteristics of the shear properties of panels made of different elements.Part of this paper was presented at the Fourth International Wood Science Symposium, Serpong, Indonesia, September 2002 相似文献
32.
Terry D Beacham Shunpei Sato Shigehiko Urawa Khai D Le Michael Wetklo 《Fisheries Science》2008,74(5):983-994
Variation at 14 microsatellite loci was surveyed in 26 chum salmon Oncorhynchus keta populations from Japan, one population from West Kamchatka and three populations from North America to determine population
structure. Microsatellites were then applied to estimate stock composition of chum salmon in mixed-stock fisheries. The genetic
differentiation index (F
st) over all populations and loci was 0.031, with individual locus values ranging from 0.010 to 0.081. Seven regional populations
were observed in Japanese chum salmon, with late-run populations from the Pacific Coast of Honshu the most distinct. Japanese
populations displayed greater genetic diversity than did those in North America. Transplantation history in some Japanese
river populations influenced their present genetic characteristics. Analysis of simulated mixtures from fishery sampling suggested
that accurate and precise regional estimates of stock composition should be produced when the microsatellites were used to
estimate stock compositions. Stock compositions for a 2005 sample of maturing, migrating chum salmon off the north-west coast
of Hokkaido near the border of the Sea of Japan and the Sea of Okhotsk indicated that this region may be a migration corridor
for Hokkaido populations from the Sea of Japan coast. Microsatellites have the ability to provide fine-scale resolution of
stock composition in Japanese coastal fisheries. 相似文献
33.
Prediction of Japanese green tea ranking by fourier transform near-infrared reflectance spectroscopy 总被引：1，自引：0，他引：1
Ikeda T Kanaya S Yonetani T Kobayashi A Fukusaki E 《Journal of agricultural and food chemistry》2007,55(24):9908-9912
A rapid and easy determination method of green tea's quality was developed by using Fourier transform near-infrared (FT-NIR) reflectance spectroscopy and metabolomics techniques. The method is applied to an online measurement and an online prediction of green tea's quality. FT-NIR was employed to measure green tea metabolites' alteration affected by green tea varieties and manufacturing processes. A set of ranked green tea samples from a Japanese commercial tea contest was analyzed to create a reliable quality-prediction model. As multivariate analyses, principal component analysis (PCA) and partial least-squares projections to latent structures (PLS) were used. It was indicated that the wavenumber region from 5500 to 5200 cm(-1) had high correlation with the quality of the tea. In this study, a reliable quality-prediction model of green tea has been achieved. 相似文献
34.
35.
Uni S Matsubayashi M Ikeda E Suzuki Y 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2003,65(3):385-388
In a survey of pathologic agents in the wild animals of central Japan, we found a Hepatozoon sp. in the lungs of Japanese black bears in Fukui, Shiga, and Gifu Prefectures, Japan. Histopathologic examination of organs and tissues from the 18 bears inspected showed hepatozoonosis in all. Immature and mature meronts were found in all lobules and between alveoli, with a few found between pleura and in connective tissue. In the lungs, inflammatory cells were not found around meronts, merozoites, or tubercles made of macro-phages including zoites, but inflammatory cells were found around degenerating cells, zoites, and tubercles. A Hepatozoon sp. has not been reported as being detected in bears of any species before. 相似文献
36.
Yoichi Kojima Ayaka Kawabata Hikaru Kobori Shigehiko Suzuki Hirokazu Ito Rie Makise Masaki Okamoto 《Journal of Wood Science》2016,62(6):518-525
Wood-based materials are fabricated with adhesives composed of various materials derived from fossil fuels. It is difficult to identify replacements for these chemical adhesives. This study explored nanofiber technologies as an alternative to these adhesives. In this study, we focused on reinforcement effects of lingo-cellulose nanofiber (LCNF) on fiberboards made from softwood and hardwood fiber. We discuss the density effects of reinforcement with LCNF because the density of medium-density fiberboard (MDF), which is widely used for construction, is standardized at about 0.60–0.80 g/cm3. Fiberboards were manufactured with three densities (0.60, 0.75, and 1.00 g/cm3). For softwood fiberboards, the bending properties for LCNF-mixed boards were higher than those for the control fiberboards at all densities. In this paper, control fiberboard means fiberboard with fiber only. For hardwood fiberboards, the bending properties for LCNF-mixed fiberboard for 1.00 g/cm3-density board were higher than those for the control fiberboard. For internal bond strength (IB), the IB for LCNF-mixed fiberboard was higher than that for the control fiberboard. The thickness swelling (TS) and weight change (WC) with water absorption for fiberboards containing LCNF were lower than those for control fiberboards. As a conclusion, physical and mechanical properties of the resulting fiberboards were significantly improved with the addition of LCNF, especially for softwood fiberboards, due to close binding between LCNF and wood fibers. 相似文献
37.
Effects of strand length and layer structure on some properties of strandboard made from bamboo 总被引：1，自引：0，他引：1
Strandboard panels were experimentally produced from moso bamboo (Phyllostachys pubescens) using various strand lengths and layer structures to evaluate the effects of manufacturing parameters on panel properties.
The strandboard was fabricated in a laboratory using diphenylmethane diisocyanate (MDI) resin and laboratory-made strands
of four lengths and four different structures. Strand alignment distributions and concentration parameter (k) values were greatly affected by strand length. A linear correlation was found between the value of k and the modulus of rupture (MOR), with correlation coefficients of 0.81 and 0.93 for unidirectional boards and three-layer
boards, respectively. This correlation may be used to predict the strength properties of boards. Bending properties were significantly
affected by both the strand length and the layer structure of the bamboo strandboard tested. Elasticity data from unidirectional
boards and random boards can be used to predict the elastic properties of three-layer boards. The linear expansion (LE) of
the random boards increased with decreasing strand length. The difficulty in mat forming and resin distribution for longer
strands could cause deviation in modulus of elasticity (MOE) and LE, especially in strand lengths around 80 mm. 相似文献
38.
Oriented strand boards (OSB) were made using sugi wood strand with different lengths at different free fall distance conditions. Strand alignment and mechanical properties of sugi OSB were evaluated. Results obtained can be summarized as follows. The alignment angle distribution was greatly affected by both free fall distance and strand length. It was found that the standard deviation of the angles can be a measure for predicting the distribution when employing the von Mises distribution function with concentration parameter. The Monte Carlo simulation showed an agreement between the theoretical considerations and the experimental results on the strand alignment. The mechanical properties as affected by both strand length and layer structure were determined. Bending properties could be equal in both directions at 25% face layer ratio. Young's modulus obtained by the in-plane vibration method showed almost linear relation to the face layer ratio. No significant differences or only a slight difference was observed for the internal bond strength, plate-shear modulus, and nail resistance properties. Further studies are necessary. 相似文献
39.
The deterioration of wood-based panels at eight sites in Japan over 7?years of outdoor exposure was investigated. In particular, the modulus of rupture (MOR) retention and internal bond strength (IB) retention after 7?years of exposure were compared among panels and sites. The deterioration of panels was greater in southern Japan than in northern Japan. The strength retentions in northern Japan decrease linearly, while those in southern Japan decreased exponentially. To quantify regional differences, deterioration rates were calculated based on three different weather conditions (precipitation, temperature, and sunlight hours), and the significance of each of these parameters on panel deterioration was determined. We found that the correlation coefficients between both IB and MOR retention and weathering intensity were the same whether we used 10-day, monthly, or daily weathering data. 相似文献
40.
Kohta Miyamoto Shigehiko Suzuki Takayoshi Inagaki Ritsuo Iwata 《Journal of Wood Science》2002,48(4):309-314
Mat consolidation behavior was investigated at various press closing times (PCTs) using hinoki (Japanese cypress) particle mats. The temperature in the core layer of the mat, press pressure, and platen distance were measured. At the plateau stage during hot pressing, the core temperature decreased with increasing PCT. The core temperature did not increase before the platen distance equaled the target board thickness in the PCT range of 4–50 s and rose slightly when the PCT exceeded 100s. There was a linear relation between the logarithm of PCT and the maximum press pressure. The density profile across board thickness was strongly affected by the PCT. As the PCT increased, the position of the peak density (PD) moved toward the core layer as the PD itself decreased. The effect of PCT on the linear expansion (LE) of the board is discussed in relation to the density profile. There was no difference in LE after high relative humidity treatment in the PCT range 4–50s. LE appeared to be related to the low density and the precured region of the board surface. The LE after drying treatment was around –0.1%, and the thickness swelling after high relative humidity and drying treatments increased with increasing PCT.Part of this report was presented at the 51st Annual Meeting of the Japan Wood Research Society, Tokyo, April 1988 相似文献