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Volume 47, Issue 4
Displaying 1-17 of 17 articles from this issue
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Minoru Miwa, Eiki Tsushima, Jun Takayasu1991 Volume 47 Issue 4 Pages 171-177
Published: March 10, 1991
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSEfforts were made to estimate the axial compressive breaking strain of PAN- and pitch-based carbon fibers by bending a rectangular epoxy beam in which a single carbon filament was embedded near the surface. The compressive breaking strain of carbon fibers increases gradually with increasing temperature in a temperature range from room temperature to about 60°C and it decreases with increasing temperature above 60°C. The low compressive breaking strain obtained at room temperature may be attributable to the high mold shrinkage. There is a linear relationship between the compressive breaking strain estimated by considering the mold shrinkage and radial compressing force owing to residual thermal stress in a temperature range from room temperature to 60°C. The true compressive breaking strain of carbonized fibers, determined by extrapolating the straight line to the radial compressive force is zero, is approximately 3 times that of graphitized fibers. The ratio of the compressive breaking strain to the tensile breaking strain is approximately 2-2.5 for carbonized fibers and 1.3 for graphitized fibers. The compressive breaking strain of fibers agrees roughly with that of unidirectional composites reinforced with the fibers.View full abstractDownload PDF (1177K) -
Nobuo Ikuta, Hiroyuki Hamada, Etsuo Nishio, Ikuo Abe, Zen-ichiro Maeka ...1991 Volume 47 Issue 4 Pages 178-183
Published: March 10, 1991
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSSingle filament coupon test was employed for investigating the mechanical properties of the interface between glass fiber and matrix in glass fiber-reinforced plastics. Particularly, interfacial effect on the fracture process accompanied by the tensile stress of the coupon was examined. The glass filament surface was treated with toluene solution containing various amounts of silane coupling agent, γ-anilinopropyltrimethoxysilane, in order to reinforce the glass-matrix interface. The fracture process was observed by applying tensile load to the coupon. The mean fragment length measured for every coupon decreased with increasing tensile stress and finally reached a value related to critical fiber length. The silane treatment apparently gave no effects on the critical value while promoted the progressive fragmentation. The fracture process was also examined by use of the variation coefficient of fracture length and the fracture positions along the filament axis. The fracture was apt to occur near the edge of a broken filament on fracture process in every case of the filaments with interfacial reinforcement. This phenomenon was interpreted in terms of the complicated stress distribution involving the stress concentration which may be generated near the fracture position by the reinforced interface.View full abstractDownload PDF (939K) -
Tatsuo Iwasaki, Kousuke Tomita1991 Volume 47 Issue 4 Pages 184-189
Published: March 10, 1991
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSStyrene was grafted onto nylon 6 fibers by a pre-irradiation technique in air. The effects of experimental conditions, such as the pre-irradiation dose, the irradiation intensity and the polymerization temperature, on the apparent percent graft as well as on the molecular weight and mole number of grafted polystyrene were investigated. The molecular weight of the grafted polystyrene was determined by the intrinsic viscosity measurement after the hydrolysis of the backbone in concentrated hydrochloric acid. An optimum irradiation dose was observed to attain the highest apparent percent graft and the highest molecular weight of grafted polystyrene. The molecular weight of grafted polystyrene decreased with the increase in the number of grafted polystyrene and the rise in the polymerization temperature, when compared at a fixed irradiation dose.View full abstractDownload PDF (409K) -
Katsumasa Tsurugai, Akira Yoshikawa, Junichi Tajima, Yoshiji Ishii1991 Volume 47 Issue 4 Pages 190-197
Published: March 10, 1991
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSFive kinds of chitosan films were prepared in order to study the antibacterial activities against E. coli and St. aureus. Film (1) was prepared by casting of an acetic acid salt of chitosan solution. Films (3) were prepared from film (1) by swelling treatment with aqueous NaOH solutions, and subsequent crosslinking with epichlorohydrin at 85°C for 2 h. Films (4) were prepared from films (3) by treating with a 5% aqueous acetic acid solution. Films (2) and (5) were prepared from film (1) and films (4) by treating with aqueous NaOH solutions, respectively. Film (1) and films (4) indicated antibacterial activities against E. coli and St. aureus. However, films (2), (3) and (5) did not show any antibacterial activities. Film (1) showed a higher antibacterial activity against E. coli and St. aureus than films (4). These results suggest that the antibacterial activities of the films (1) and (4) are dependent on their abilities of the formation of acetic acid salt and also on their structures of acetic acid salt. By the treatment with an aqueous acetic acid solution, the antibacterial activities of films (4) were revealed without a remarkable decrease in the activity after several cyclic treatments with an aqueous NaOH solution and with an aqueous acetic acid solution.View full abstractDownload PDF (584K) -
Isao Ikeda, Issei Sato, Kimihiro Suzuki1991 Volume 47 Issue 4 Pages 198-202
Published: March 10, 1991
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSThe synthesis of lauric esters of mono-and polyhydric alcohols was studied in organic sol. vents using lipase from Candida cylindracea immobilized on poly (vinyl alcohol)-co-poly(ethyleneimine) gels. The conversion to n-hexyl laurate increased with increasing water content in the reaction system and levelled off above 3%. A similar result was obtained with wet-treated immobilized lipase. The synthesis of n-hexyl laurate in isooctane revealed the highest conversion and the highest rate of esterification among the organic solvents used. Fifty units of lipase was necessary to achieve the almost quantitative esterification in 22 h. Lauric esters of polyhydric alcohols, such as glycerol, ethylene glycol and 1, 3-butanediol, were similarly synthesized with a relatively high conversion in isooctane. Esters prepared were characterized by gel permeation chromatography.View full abstractDownload PDF (324K) -
Sadao Hayashi, Yoshiaki Kumamoto, Takashi Suzuki, Toshihiro Hirai, Mor ...1991 Volume 47 Issue 4 Pages 203-213
Published: March 10, 1991
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSThe formation of geometrical Moiré patterns was investigated by superposing two and more figure sheets of the same dot arrangement. In order to obtain compactly well-regulated patterns by this multi-superposing method, it was indispensable to keep the angles between the first rotating sheet (B) and the second rotating sheet (C) at θC=θ'-θB, where θB and θC are the rotating angle of B and C sheets against the fixed sheet, respectively, and θ' is the period of patterns found when superposing two sheets. Consequently, the fundamental unit of patterns was formed as a rhomb which was symmetrical about the X and Y axes. It was further illustrated that a remarkable increase in dot number in unit area by superposing five sheets or more makes instead an outward appearance of patterns worse, except for a number of examples. Many Moiré patterns obtained by this multi-superposing method agreed very closely with frameworks of geometrical printing patterns which were fashionable in old Japan.View full abstractDownload PDF (1029K) -
1991 Volume 47 Issue 4 Pages P228
Published: 1991
Released on J-STAGE: November 28, 2008
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YASUSUKE TAKAHASHI1991 Volume 47 Issue 4 Pages P171-P176
Published: March 10, 1991
Released on J-STAGE: November 28, 2008
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MASARU MATSUOKA1991 Volume 47 Issue 4 Pages P177-P181
Published: March 10, 1991
Released on J-STAGE: November 28, 2008
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AKIRA SAKAMOTO1991 Volume 47 Issue 4 Pages P182-P186
Published: March 10, 1991
Released on J-STAGE: November 28, 2008
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SHINJI AMAYA1991 Volume 47 Issue 4 Pages P187-P192
Published: March 10, 1991
Released on J-STAGE: November 28, 2008
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TOSHIO KANEKO1991 Volume 47 Issue 4 Pages P193-P196
Published: March 10, 1991
Released on J-STAGE: November 28, 2008
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TADAO SETO1991 Volume 47 Issue 4 Pages P197-P201
Published: March 10, 1991
Released on J-STAGE: November 28, 2008
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RYOHEI TAKIGUCHI1991 Volume 47 Issue 4 Pages P202-P206
Published: March 10, 1991
Released on J-STAGE: November 28, 2008
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TAKUYA YOKOKAWA, TOSHIKI TAGUCHI1991 Volume 47 Issue 4 Pages P207-P211
Published: March 10, 1991
Released on J-STAGE: November 28, 2008
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KENJI SAWAKI1991 Volume 47 Issue 4 Pages P212-P214
Published: March 10, 1991
Released on J-STAGE: November 28, 2008
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YOSHITARO KUMAGAI1991 Volume 47 Issue 4 Pages P215-P219
Published: March 10, 1991
Released on J-STAGE: November 28, 2008
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