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11.
Shigeru Yamauchi Yoichi Sakai Yasuo Watanabe Michael Kenya Kubo Hideaki Matsue 《Journal of Wood Science》2007,53(4):324-331
The distributions of boron in Japanese cedar (Cryptomeria japonica D. Don) sapwood blocks treated with aqueous or methanolic boric acid [B(OH)3] solutions were explored through Raman spectroscopy and prompt gamma-ray analysis (PGA). B(OH)3 was the sole boron species observed in Raman spectra of the wood blocks treated with either solution. Plots of weight gain
of the treated wood blocks versus boron concentration in treatment solutions were found to be linear. The results indicated
that the methanolic solution makes it possible to impregnate wood with much larger amounts of boron than the aqueous solution.
PGA confirmed that B(OH)3 was highly enriched near the end grains of the treated wood blocks. Raman measurements suggested that boron content in the
bulk of the wood block is not as large as expected from the weight gain of the treated wood blocks when an ordinary air-drying
method is used. It was concluded that the aqueous solution impregnates the cell walls of wood with boron more easily than
the methanolic solution.
Part of this report was presented at the 55th (Kyoto, March 2005) and 56th (Akita, August 2006) Annual Meetings of the Japan
Wood Research Society. This article follows the previous rapid communication “Analysis of boron in wood treated with boric
acid solutions using Doppler broadening method of prompt gamma-rays.” J Wood Sci (2006) 52:279–281 相似文献
12.
Masaki?HaradaEmail author Kohei?Komatsu Tomoyuki?Hayashi Masahiko?Karube 《Journal of Wood Science》2004,50(5):450-454
A wooden lattice floor with high stiffness and damping capacity has been developed to solve noise problems in wooden apartment houses. The lattice floor consisted of Douglas fir glulam beams with inserted steel plate joints and drift pins. To examine the structural performance of the floor, dynamic excitation and static loading tests were conducted on the full size floor. The first and second order resonance frequencies of the floor were 13.5Hz and 27.0Hz, respectively. These frequencies are similar to the peak frequency of a conventional wooden floor and the combined floor fabricated from glued laminated timber and iron. The maximum static load of the floor was 127kN. The apparent flexural rigidity was less than half the value of several floors studied in the past. However, it is considered that the stiffness is improved by constructing panels and this floor has almost equivalent performance. Relative deflection was not affected by the loading history.Part of this study was presented at the International Wood Engineering Conference, New Orleans, October 1996. 相似文献
13.
Toshihiro Hata Kenji Umemura Hidefumi Yamauchi Akihiro Nakayama Shuichi Kawai Hikaru Sasaki 《Journal of Wood Science》2001,47(2):115-123
A new spiral-winder was developed for continuous manufacturing of cylindrical laminated veneer lumber (LVL), and a suitable resin adhesive for this cylindrical LVL manufacturing system was investigated. This phase was followed by trial manufacturing and evaluation of cylindrical LVL with the optimum resin adhesive identified. The results are summarized as follows. (1) The shortest gelation time was recorded with a mixture of two commercial resorcinol based resins (DF-1000 and D-33) at a weight ratio of 2575. (2) Bath temperature had a remarkable effect on the gelation time of the adhesive mix. (3) High bonding strength was recorded by 2575 DF-1000/D-33 adhesive mix at a high press temperature despite a short pressing duration. Based on the results of items (1) to (3), 2575 DF-1000/ D-33 is recommended for use in the new spiral-winder. (4) The mechanical properties of cylindrical LVL could be improved by using 2575 DF-1000/D-33 with wider veneer width and longer pressing time. (5) The mechanical properties, especially the modulus of rupture, of the cylindrical LVL manufactured require further improvement for practical structural application. 相似文献
14.
On mechanical behavior of traditional timber shear wall in Taiwan I: background and theory derivation 总被引:1,自引:0,他引:1
The objectives of this study were to explore the mechanical behavior of traditional timber shear walls in Taiwan and to propose
a theoretical model to predict their lateral force resistance. An extensive field investigation was conducted, and the dimensions,
tectonic detail, and materials used were recorded. The data collected were used as the reference for theoretical derivation
and experimental design. In the theoretical model, the moment resistance of entire shear walls was derived from the contributions
of the moment-resisting capacity supplied not only by embedment and friction action between board units and beams but also
the dowel action of bamboo nails. Timber shear walls with various geometric conditions and material properties are considered.
The theoretical model demonstrated in this study can be used to predict the mechanical behavior of timber shear walls and
will be verified by experiments in our next article. 相似文献
15.
The bending properties of split bamboo culm were compared with those of spruce and beech wood specimens. The bamboo allowed
large flexural deformation since its outer layer retains the tensile stress while the softer inner layer undergoes large compressive
deformation. The results suggested that the combination of the fiber-rich outer part and the compressible inner part was responsible
for the flexural ductility of split bamboo. To clarify the compressible nature of the inner part of bamboo, the longitudinal
surfaces of the bamboo and wood specimens were microscopically observed before and after a large longitudinal compression.
Although the wood specimens showed serious and localized buckling, the inner part of the bamboo specimens showed no such visible
buckling. In the latter case, the foam-like parenchyma cells absorbed the large compressive deformation by their microscopic
buckling and simultaneously, the alignment of sclerenchyma fibers was maintained by the surrounding parenchyma matrix. The
flexural elasticity of the bamboo was compared to that of the wood in respect of remaining strain during cyclic bending tests.
No clear difference was recognized between their remaining strains. This fact indicated that the bamboo was not so flexible
elastically, although its fiber–foam combination and intelligent fiber distribution improve flexural ductility. 相似文献
16.
The radial compression behaviors of acetylated cedar wood were measured in various liquids. The compressive Young’s modulus
(E) of acetylated wood was reduced by soaking in water, toluene, and acetone, but it was always greater than that of water-swollen
unmodified wood at the same swelling level. The behaviors of acetone-swollen unmodified wood were similar to those of acetylated
wood rather than those of water-swollen unmodified wood. These results indicated that the swelling of hydrophobic wood components
had a lesser influence on the E of wood than the water-swelling of unmodified hydrophilic components. After large compression (ε > 45%), a part of the strain
remained unrecovered because of irreversible mechanical deformation. Since the remaining strain was smaller in the wood specimens
indicating greater stress relaxation, it was assumed that the viscoelastic deformation of amorphous matrix components is important
for lesser irreversible deformation and effective shape recovery of wood. In contrast with water-swollen unmodified wood,
the acetylated wood and acetone-swollen unmodified wood exhibited greater shape recovery despite their relatively higher E. This suggested that the swelling of hydrophobic wood components reduced the viscosity of the matrix rather than its elasticity,
resulting in more effective shape recovery with lesser softening. 相似文献
17.
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
18.
The embedment tests of laminated veneer lumber (LVL) with two moduli of elasticity (MOE; 7.8 GPa and 9.8GPa), parallel strand lumber (PSL), and laminated strand lumber (LSL) were conducted in accordance with ASTM-D 5764. The load-embedment relation for each of these engineered wood products (EWPs) was established. The directional characteristics of bearing strength (e), initial stiffness (k
e), and effective elastic foundation depth were obtained from the tested results. The effective elastic foundation depth (=E/k
e,E = MOE), based on the theory of a beam on elastic foundation, was obtained from thek
e and MOE. An of 90° (perpendicular to the grain) was calculated by dividingE
90 [MOE of 90° from the compression test, but MOE of 0° (E
0), parallel to the grain, obtained from the bending test] byk
e90, the initial stiffness of 90°. This study aimed to obtain the bearing characteristics of each EWP, taking into consideration their anisotropic structures, for estimating the fastening strength of a dowel-type fastener. The relations between the bearing coefficients (
e,k
e,) on the loading direction and dowel diameter were established from the load-embedment curves. Based on the results of the embedment test, tested EWPs showed different tendencies in all directions from wood and glued laminated timber.Part of this study was presented at the 49th Annual Meeting of the Japan Wood Research Society, Tokyo, April 1999 相似文献
19.
Kohei MURAKAMI Tomohiro YONEZAWA Naoaki MATSUKI 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2015,77(12):1715-1717
Idiopathic polyarthritis (IPA) is a very common inflammatory arthropathy in the dog.
Canine IPA is diagnosed mainly by detecting increased number of leukocytes in the synovial
fluid (SF), which is easily influenced by glucocorticoid therapy. We obtained 31 SF
samples from 24 IPA dogs prior to (n=19) and/or after
(n=12) 1 to 10 weeks of glucocorticoid therapy. The SF total protein
concentrations of IPA dogs were significantly higher than those of dogs with non-arthritis
diseases (n=34) and healthy controls (n=10). Our data
revealed that the SF total protein concentrations are not influenced by several weeks of
glucocorticoid therapy. Hence, the SF total protein concentration is applicable as a
diagnostic marker of canine IPA even when the patients are receiving glucocorticoid
therapy. 相似文献
20.
Takafumi SUZUKI Naohito NISHII Satoshi TAKASHIMA Tatsuya MATSUBARA Atsushi IWASAWA Hirofumi TAKEUCHI Kohei TAHARA Tatsuyuki HACHISU Hitoshi KITAGAWA 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2015,77(11):1379-1383
Polyclonal immunoglobulin (Ig) G autoantibodies against insulin have been
identified in sera of healthy cats. We purified and fractionated insulin-binding IgGs from
cat sera by affinity chromatography and analyzed affinity of insulin-binding IgGs for
insulin and their epitopes. Following the passing of fraction A, which did not bind to
insulin, insulin-binding IgGs were eluted into two fractions, B and C, by affinity
chromatography using a column fixed with bovine insulin. Dissociation constant (KD) values
between insulin-binding IgGs and insulin, determined by surface plasmon resonance analysis
(Biacore™system), were 1.64e−4 M for fraction B (low affinity IgGs) and
2e−5 M for fraction C (high affinity IgGs). Epitope analysis was conducted
using 16 peptide fragments synthesized in concord with the amino acid sequence of feline
insulin by an enzyme-linked immunosorbent assay. Fractions B and C showed higher
absorbance (affinity) of the peptide fragment of 10 amino acid residues at the
carboxyl-terminal of the B chain (peptide No. 19), followed by peptide fragments of 6 to
15 amino acid residues of the B chain (peptide No. 8). Fraction C showed a higher
absorbance to 7 to 16 amino acid residues of the B chain (peptide No. 5) compared with the
absorbance of fraction B. Polyclonal insulin-binding IgGs may form a macromolecule complex
with insulin through the multiple affinity sites of IgG molecules. Feline insulin-binding
IgGs are multifocal and may be composed of multiple IgG components and insulin. 相似文献