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21.
The durability of wood-based panels was evaluated by comparing the bending properties of panels subjected to five accelerated
aging treatments with the bending properties of panels that had experienced 5 years of outdoor exposure in Shizuoka City,
Japan. In each accelerated aging treatment, methylene diphenyl diisocyanate-bonded panels showed higher bending retention
than phenol formaldehyde (PF)-bonded panels. The bending retentions after six repeated cycles of the JIS-B, APA D-1, and ASTM
treatments showed a correspondence of nearly one-to-one in the data for the three different treatments. The Shizuoka City
5-year outdoor exposure test data showed that the bending retentions of all panels decreased with time. In particular, the
bending retentions of PF resin-bonded particleboard and oriented strandboard made from aspen were less than 30% and 10% of
the original values, respectively, after the 5-year exposure period. The deterioration of the bending properties after the
5-year outdoor exposure in Shizuoka City was the same as that for six repetitions of the ASTM treatment. 相似文献
22.
Yoichi Kojima Jun Minamino Akiko Isa Shigehiko Suzuki Hirokazu Ito Rie Makise Masaki Okamoto 《Journal of Wood Science》2013,59(5):396-401
Wood-based materials are extensively used for residual construction worldwide, especially in Japan. Most wood-based materials are fabricated using adhesives, some of which are not environmentally friendly. As an alternative to chemical adhesives, we explored this issue using nanofiber technology, especially the use of cellulose nanofibers (CNF), as reinforcement in wood flour (WF) board to replace chemical adhesives. We found that CNF could be easily made by pulverization in a ball mill. The physical and mechanical properties of WF board were improved by the three-dimensional binding effects of the CNF. 相似文献
23.
Yurika Matoba Norio Kondo Seishi Akino Fujio Kodama Shigeo Naito Shigehiko Ebe 《Journal of General Plant Pathology》2008,74(1):81-85
Five Pythium species (Pythium irregulare, P. mamillatum, P. myriotylum, P. spinosum and P. ultimum var. ultimum) were isolated from the hypocotyls and roots of kidney bean plants with damping-off from a commercial field and from experimental
plots that have undergone either continuous cropping with kidney bean or rotational cropping with arable crops. In inoculation
tests, all five Pythium species were pathogenic to kidney bean. This is the first report of damping-off of kidney bean caused by Pythium species; we named this disease damping-off of kidney bean.
The nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under accession numbers AB291811, AB291944
and AB291945. 相似文献
24.
Yoko Yamashita Toru Takeuchi Masataka Okuyama Jun Sasaki Kakumasa Onodera Mikako Sato Chihiro Souma Shigehiko Ebe 《Breeding Science》2014,64(4):404-408
The yellowing strain of Soybean dwarf virus (SbDV-YS) causes yellowing and yield loss in common bean (Phaseolus vulgaris). The most effective control is achieved through breeding for resistance. An indeterminate climbing cultivar with a white seed coat, ‘Oofuku’, is resistant to SbDV-YS in inoculation tests. We crossed ‘Oofuku’ with an elite cultivar, ‘Taisho-Kintoki’, which is SbDV-YS-susceptible, determinate dwarf with a red-purple seed coat, and performed amplified-fragment-length polymorphism analysis of F3 lines. From nucleotide sequences of the resistant-specific fragments and their flanking regions, we developed five DNA markers, of which DV86, DV386, and DV398 were closely linked to Sdvy-1, a resistance gene. Using the markers, we developed ‘Toiku-B79’ and ‘Toiku-B80’, the near-isogenic lines (NILs) incorporating Sdvy-1 in the background of ‘Taisho-Kintoki’. The NILs had similar growth habit, maturity date and seed shape to those of ‘Taisho-Kintoki’. The quality of boiled beans was also similar, except that the NILs had more seed coat cracking than ‘Taisho-Kintoki’. The NILs showed no SbDV-YS infection in inoculation tests. We suggest that Sdvy-1 is a useful source of SbDV-YS resistance in common bean. 相似文献
25.
The durability of wood-based panels is one of the most important properties when they are used in residential construction.
The main objectives of this study were to investigate the quantitative relationship between the Wet-bending A test and the
Wet-bending B test, examine the aging effects of the treatments specified in the wet-bending methods, and discuss the relationship
between wet-bending and outdoor aging tests conducted in Shizuoka, Japan. Wet-bending tests, internal bond tests after humidity
treatment, and outdoor aging tests in Shizuoka were conducted using eight types of commercial wood-based panels. A linear
relationship was found between the load-carrying capacity (LCC) from the Wet-bending A test and the LCC from the Wet-bending
B test. The LCC from Wet-bending B could be obtained from LCC from Wet-bending A by multiplying it by 0.9, which may be applicable
as a quantitative ratio of aging effects between the two. LCC for methylenediphenyl diisocyanate-bonded panels recovered to
almost 100% of the initial strength. A certain relationship was found between the LCC after Wet-bending A and the LCC after
a 1-year outdoor exposure in Shizuoka. Internal bond strength showed a good correlation between the JIS-A treatment and the
1-year outdoor exposure treatment. 相似文献
26.
Particleboards were fabricated in the laboratory with different board densities and resin contents to evaluate linear expansion when exposed to both vapor and liquid water. Density profiles were measured to determine the relation to the elastic constants and to the dimensional properties of the boards. It was found that density profiles were affected by the board density and resin content applied. The high-density layer formed in the thickness direction affected the elastic constant measurements. A model introduced to predict the linear expansion closely matched the data during exposure to water. Under conditions of 40°C and 90% humidity, linear expansion increased with increasing board density. An increase in resin content from 6% to 12% slightly increased the linear expansion and decreased the thickness swelling. A linear relation was found between board density and linear expansion per unit of moisture content change. 相似文献
27.
In this study, the deterioration of wood-based panels at eight sites in Japan was investigated using outdoor exposure tests.
In particular, the modulus of rupture (MOR) retention and internal bond strength (IB) retention after 5-year exposures were
compared among panels and sites. The deterioration of panels located in southern Japan was higher than that of panels in northern
Japan. To quantify the regional differences, the deterioration rates were calculated; the values showed clear regional differences.
The deterioration rate for areas that receive much rain in the summer was higher than the rates for other sites. To eliminate
regional differences, we carried out an analysis in terms of the “weathering intensity,” a factor which combines weather conditions
(precipitation and temperature). Panels for which deterioration progressed extensively during exposure periods showed a strong
correlation between strength retention and the weathering intensity. The significance of these parameters is discussed. 相似文献
28.
Consensus is emerging that the medial frontal lobe of the brain is involved in monitoring performance, but precisely what is monitored remains unclear. A saccade-countermanding task affords an experimental dissociation of neural signals of error, reinforcement, and conflict. Single-unit activity was monitored in the anterior cingulate cortex of monkeys performing this task. Neurons that signaled errors were found, half of which responded to the omission of earned reinforcement. A further diversity of neurons signaled earned or unexpected reinforcement. No neurons signaled the form of conflict engendered by interruption of saccade preparation produced in this task. These results are consistent with the hypothesis that the anterior cingulate cortex monitors the consequences of actions. 相似文献
29.
30.
This study examined the effects of density and layer structure on the mechanical properties and dimensional stability of strandboard
manufactured from moso bamboo (Phyllostachys pubescens). The strandboard was fabricated in a laboratory at five densities and three different structures including a randomly oriented
homogenous board, a unidirectionally oriented homogenous board, and a three-layered board with a cross-oriented core layer
(BOSB). Bamboo strand alignment distribution could be predicted using the von Mises distribution function. Bending properties
increased with increasing density and were affected by layer structure. The modulus of rupture (MOR) of the threelayered board
in the parallel direction increased remarkably compared with the random board MOR; in the perpendicular direction, it exhibited
less strength reduction. Elastic properties of the three-layered board could be predicted using elastic constants of the unidirectional
board. Internal bond strength (IB) was greatly affected by density, but the layer structure effect did not appear in IB. Linear
expansion per unit moisture change ranged from 0.017 to 0.022 for random and three-layered boards; these values are comparable
with or lower than values for commercial board. 相似文献