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Shigehiro Nishijima - One of the best experts on this subject based on the ideXlab platform.
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Thermal Expansion Coefficient of Unidirectional High-Strength Polyethylene Fiber Reinforced Plastics at Low Temperature
Journal of Composite Materials, 2006Co-Authors: Atsuhiko Yamanaka, Toshihiro Kashima, Masayuki Tsutsumi, Kimiko Ema, Yoshinobu Izumi, Shigehiro NishijimaAbstract:High-strength Polyethylene Fiber (Dyneema®, DF) has a negative linear thermal expansion coefficient in the direction of the Fiber. Thermal expansion coefficients of Fiber-reinforced plastics are of...
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Thermal conductivity of high strength Polyethylene Fiber in low temperature
Journal of Polymer Science Part B: Polymer Physics, 2005Co-Authors: Atsuhiko Yamanaka, Toshihiro Kashima, Kimiko Ema, Yoshinobu Izumi, Tooru Kitagawa, Hiroyuki Fujishiro, Manabu Ikebe, Shigehiro NishijimaAbstract:High strength Polyethylene Fiber (Toyobo, Dyneema® Fiber, hereinafter abbreviated to DF) used as reinforcement of Fiber-reinforced plastics for cryogenic use has a high thermal conductivity. To understand the thermal conductivity of DF, the relation between Fiber structure and thermal conductivity of several kinds of Polyethylene Fibers having different modulus from 15 to 134 GPa (hereinafter abbreviated to DFs) was investigated. The mechanical series-parallel model composed of crystal and amorphous was applied to DFs for thermal conductivity. This mechanical model was obtained by crystallinity and crystal orientation angle measured by solid state NMR and X-ray. Thermal conductivity of DF in Fiber direction was dominated by that of the continuous crystal region. The thermal conductivity of the continuous crystal part estimated by the mechanical model increases from 16 to 900 mw/cmK by the increasing temperature from 10 to 150K, and thermal diffusivity of the continuous crystal part was estimated to about 100 mm2/s, which is almost temperature independent. The phonon mean free path of the continuous crystal region of DF obtained by thermal diffusivity is almost temperature independent and its value about 200 A. With the aforementioned, the mechanical series-parallel model composed of crystal and amorphous regions could be applied to DFs for thermal conductivity. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1495–1503, 2005
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Thermal strain of high strength Polyethylene Fiber in low temperature
Journal of Applied Polymer Science, 2004Co-Authors: Atsuhiko Yamanaka, Toshihiro Kashima, Masayuki Tsutsumi, Kimiko Ema, Yoshinobu Izumi, Tooru Kitagawa, Hiroyuki Fujishiro, Shigehiro NishijimaAbstract:High strength Polyethylene Fiber (Toyobo, Dyneema® Fiber: hereinafter abbreviated to DF) has a negative thermal expansion coefficient. Relation between Fiber structure and thermal strain of DF used as reinforcement of DF reinforced plastic (DFRP) for cryogenic use was investigated. The crystallinities and orientation angles of several kinds of Polyethylene Fibers having different modulus from 15 to 134Gpa (herein after abbreviated to DFs) were measured by NMR and X-ray. We obtained the parameters of the mechanical series-parallel model composed of crystal and amorphous by crystallinity and modulus. Thermal expansion coefficients of DFs were estimated by mechanical series-parallel model. All DFs having different modulus showed negative thermal expansion coefficients in the temperature range from 180 to 300K, and absolute values of those markedly increased by increasing tensile modulus of DF. The estimated thermal expansion coefficients showed negative values, and thermal strains showed a similar curve to observed ones mostly. Average thermal expansion coefficients in the temperature range from 180 to 300K estimated by mechanical model agreed with the observed ones. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2918–2925, 2004
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thermal strain of pipes composed with high strength Polyethylene Fiber reinforced plastics at cryogenic temperatures
Advances in cryogenic engineering, 1996Co-Authors: Toshihiro Kashima, Atsuhiko Yamanaka, Shigehiro Nishijima, Toichi OkadaAbstract:High strength Polyethylene Fiber (Dyneema® Fiber; hereinafter abbreviated to DF) has a large negative thermal expansion coefficient. Several kinds of pipes were prepared by means of filament winding or sheet winding method. The thermal strain or residual stress of those pipes were measured at liquid nitrogen temperature. The thermal strain was also calculated and was compared with the measured values. The circumferential thermal strain of the inner surface was found to be much different from that of outer surface. The circumferential strain changed with the ratio of inner diameter to thickness of pipes. The mean thermal strain of inner and outer surface was found to agree well with that of calculated value. It was confirmed that the negative thermal expansion can be realized even in the pipes. The design methodology of the pipes with negative thermal expansion was discussed.
Atsuhiko Yamanaka - One of the best experts on this subject based on the ideXlab platform.
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Development of High Performance Fiber Reinforced Composite with Negative Thermal Expansion Property
Advanced Materials Research, 2008Co-Authors: Hua Yang, Atsuhiko Yamanaka, Qing-qing Ni, Toshiaki NatsukiAbstract:There are exists positive thermal expansion property for almost all materials. However, in many cases, the material property with negative thermal expansion is requested for engineering applications. This work is to develop high performance Fiber-reinforced composites with negative thermal expansion by using high strength Polyethylene Fiber Dyneema®, high strength PBO Fiber ZYLON®, aramid Fiber Technora ® and carbon Fibers.
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Thermal Expansion Coefficient of Unidirectional High-Strength Polyethylene Fiber Reinforced Plastics at Low Temperature
Journal of Composite Materials, 2006Co-Authors: Atsuhiko Yamanaka, Toshihiro Kashima, Masayuki Tsutsumi, Kimiko Ema, Yoshinobu Izumi, Shigehiro NishijimaAbstract:High-strength Polyethylene Fiber (Dyneema®, DF) has a negative linear thermal expansion coefficient in the direction of the Fiber. Thermal expansion coefficients of Fiber-reinforced plastics are of...
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Thermal conductivity of high strength Polyethylene Fiber in low temperature
Journal of Polymer Science Part B: Polymer Physics, 2005Co-Authors: Atsuhiko Yamanaka, Toshihiro Kashima, Kimiko Ema, Yoshinobu Izumi, Tooru Kitagawa, Hiroyuki Fujishiro, Manabu Ikebe, Shigehiro NishijimaAbstract:High strength Polyethylene Fiber (Toyobo, Dyneema® Fiber, hereinafter abbreviated to DF) used as reinforcement of Fiber-reinforced plastics for cryogenic use has a high thermal conductivity. To understand the thermal conductivity of DF, the relation between Fiber structure and thermal conductivity of several kinds of Polyethylene Fibers having different modulus from 15 to 134 GPa (hereinafter abbreviated to DFs) was investigated. The mechanical series-parallel model composed of crystal and amorphous was applied to DFs for thermal conductivity. This mechanical model was obtained by crystallinity and crystal orientation angle measured by solid state NMR and X-ray. Thermal conductivity of DF in Fiber direction was dominated by that of the continuous crystal region. The thermal conductivity of the continuous crystal part estimated by the mechanical model increases from 16 to 900 mw/cmK by the increasing temperature from 10 to 150K, and thermal diffusivity of the continuous crystal part was estimated to about 100 mm2/s, which is almost temperature independent. The phonon mean free path of the continuous crystal region of DF obtained by thermal diffusivity is almost temperature independent and its value about 200 A. With the aforementioned, the mechanical series-parallel model composed of crystal and amorphous regions could be applied to DFs for thermal conductivity. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1495–1503, 2005
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Thermal strain of high strength Polyethylene Fiber in low temperature
Journal of Applied Polymer Science, 2004Co-Authors: Atsuhiko Yamanaka, Toshihiro Kashima, Masayuki Tsutsumi, Kimiko Ema, Yoshinobu Izumi, Tooru Kitagawa, Hiroyuki Fujishiro, Shigehiro NishijimaAbstract:High strength Polyethylene Fiber (Toyobo, Dyneema® Fiber: hereinafter abbreviated to DF) has a negative thermal expansion coefficient. Relation between Fiber structure and thermal strain of DF used as reinforcement of DF reinforced plastic (DFRP) for cryogenic use was investigated. The crystallinities and orientation angles of several kinds of Polyethylene Fibers having different modulus from 15 to 134Gpa (herein after abbreviated to DFs) were measured by NMR and X-ray. We obtained the parameters of the mechanical series-parallel model composed of crystal and amorphous by crystallinity and modulus. Thermal expansion coefficients of DFs were estimated by mechanical series-parallel model. All DFs having different modulus showed negative thermal expansion coefficients in the temperature range from 180 to 300K, and absolute values of those markedly increased by increasing tensile modulus of DF. The estimated thermal expansion coefficients showed negative values, and thermal strains showed a similar curve to observed ones mostly. Average thermal expansion coefficients in the temperature range from 180 to 300K estimated by mechanical model agreed with the observed ones. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2918–2925, 2004
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Sound velocity of high-strength polymer with negative thermal expansion coefficient
Physica B-condensed Matter, 2003Co-Authors: Ryuji Nomura, M. Ueno, Yuichi Okuda, S. Burmistrov, Atsuhiko YamanakaAbstract:Abstract Sound velocities of Fiber reinforced plastics (FRPs) were measured along the Fiber axis at temperatures between 360 and 77 K . We used two kinds of the high-strength crystalline polymer Fibers, Polyethylene (Dyneema) and polybenzobisoxazole (Zylon), which have negative thermal expansion coefficients. They also have high thermal conductivities and high resistances for flash over voltage, and are expected as new materials for coil bobbins or spacers at cryogenic temperatures. They have very large sound velocities of about 9000 (m/s) at 77 K , which are 4.5 times larger than that of the ordinary Polyethylene Fiber.
Toshihiro Kashima - One of the best experts on this subject based on the ideXlab platform.
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Thermal Expansion Coefficient of Unidirectional High-Strength Polyethylene Fiber Reinforced Plastics at Low Temperature
Journal of Composite Materials, 2006Co-Authors: Atsuhiko Yamanaka, Toshihiro Kashima, Masayuki Tsutsumi, Kimiko Ema, Yoshinobu Izumi, Shigehiro NishijimaAbstract:High-strength Polyethylene Fiber (Dyneema®, DF) has a negative linear thermal expansion coefficient in the direction of the Fiber. Thermal expansion coefficients of Fiber-reinforced plastics are of...
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Thermal conductivity of high strength Polyethylene Fiber in low temperature
Journal of Polymer Science Part B: Polymer Physics, 2005Co-Authors: Atsuhiko Yamanaka, Toshihiro Kashima, Kimiko Ema, Yoshinobu Izumi, Tooru Kitagawa, Hiroyuki Fujishiro, Manabu Ikebe, Shigehiro NishijimaAbstract:High strength Polyethylene Fiber (Toyobo, Dyneema® Fiber, hereinafter abbreviated to DF) used as reinforcement of Fiber-reinforced plastics for cryogenic use has a high thermal conductivity. To understand the thermal conductivity of DF, the relation between Fiber structure and thermal conductivity of several kinds of Polyethylene Fibers having different modulus from 15 to 134 GPa (hereinafter abbreviated to DFs) was investigated. The mechanical series-parallel model composed of crystal and amorphous was applied to DFs for thermal conductivity. This mechanical model was obtained by crystallinity and crystal orientation angle measured by solid state NMR and X-ray. Thermal conductivity of DF in Fiber direction was dominated by that of the continuous crystal region. The thermal conductivity of the continuous crystal part estimated by the mechanical model increases from 16 to 900 mw/cmK by the increasing temperature from 10 to 150K, and thermal diffusivity of the continuous crystal part was estimated to about 100 mm2/s, which is almost temperature independent. The phonon mean free path of the continuous crystal region of DF obtained by thermal diffusivity is almost temperature independent and its value about 200 A. With the aforementioned, the mechanical series-parallel model composed of crystal and amorphous regions could be applied to DFs for thermal conductivity. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1495–1503, 2005
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Thermal strain of high strength Polyethylene Fiber in low temperature
Journal of Applied Polymer Science, 2004Co-Authors: Atsuhiko Yamanaka, Toshihiro Kashima, Masayuki Tsutsumi, Kimiko Ema, Yoshinobu Izumi, Tooru Kitagawa, Hiroyuki Fujishiro, Shigehiro NishijimaAbstract:High strength Polyethylene Fiber (Toyobo, Dyneema® Fiber: hereinafter abbreviated to DF) has a negative thermal expansion coefficient. Relation between Fiber structure and thermal strain of DF used as reinforcement of DF reinforced plastic (DFRP) for cryogenic use was investigated. The crystallinities and orientation angles of several kinds of Polyethylene Fibers having different modulus from 15 to 134Gpa (herein after abbreviated to DFs) were measured by NMR and X-ray. We obtained the parameters of the mechanical series-parallel model composed of crystal and amorphous by crystallinity and modulus. Thermal expansion coefficients of DFs were estimated by mechanical series-parallel model. All DFs having different modulus showed negative thermal expansion coefficients in the temperature range from 180 to 300K, and absolute values of those markedly increased by increasing tensile modulus of DF. The estimated thermal expansion coefficients showed negative values, and thermal strains showed a similar curve to observed ones mostly. Average thermal expansion coefficients in the temperature range from 180 to 300K estimated by mechanical model agreed with the observed ones. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2918–2925, 2004
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Coil bobbin composed of high-strength Polyethylene Fiber reinforced plastics for a stable high-field superconducting magnet
IEEE Transactions on Applied Superconductivity, 2001Co-Authors: Atsuhiko Yamanaka, Toshihiro Kashima, Katsuhiro HosoyamaAbstract:High-field superconducting solenoid magnets sometimes quench by wire motion induced by electromagnetic force. Fiber reinforced plastic [Dyneema Fiber reinforced plastic (DFRP)] pipes composed of high-strength Polyethylene Fiber by filament winding method could be constructed so as to expand in the circumferential direction when cooled to low temperature with an appropriate selection of winding angle and shape of the pipes. In the case of a superconducting coil fabricated with a DFRP bobbin, it is expected that wire motions in high field are decreased by expansion of the coil bobbin. In this paper, tap voltage between both ends of the coils fabricated with DFRP bobbin and stainless steel (SUS) bobbin were measured with increasing current. The coil using SUS bobbin showed many sharp peaks in tap voltage induced by quick wire motions. In contrast, those using DFRP bobbin showed only a few small peaks. These results suggest that wire motions were constrained by DFRP bobbin. The training effects were observed in both cases.
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thermal strain of pipes composed with high strength Polyethylene Fiber reinforced plastics at cryogenic temperatures
Advances in cryogenic engineering, 1996Co-Authors: Toshihiro Kashima, Atsuhiko Yamanaka, Shigehiro Nishijima, Toichi OkadaAbstract:High strength Polyethylene Fiber (Dyneema® Fiber; hereinafter abbreviated to DF) has a large negative thermal expansion coefficient. Several kinds of pipes were prepared by means of filament winding or sheet winding method. The thermal strain or residual stress of those pipes were measured at liquid nitrogen temperature. The thermal strain was also calculated and was compared with the measured values. The circumferential thermal strain of the inner surface was found to be much different from that of outer surface. The circumferential strain changed with the ratio of inner diameter to thickness of pipes. The mean thermal strain of inner and outer surface was found to agree well with that of calculated value. It was confirmed that the negative thermal expansion can be realized even in the pipes. The design methodology of the pipes with negative thermal expansion was discussed.
Zahra Jowkar - One of the best experts on this subject based on the ideXlab platform.
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The effect of short Polyethylene Fiber with different weight percentages on diametral tensile strength of conventional and resin modified glass ionomer cements.
Journal of clinical and experimental dentistry, 2017Co-Authors: Farahnaz Sharafeddin, Seyed-ali Ghaboos, Zahra JowkarAbstract:The aim of this study was to investigate the effect of Polyethylene Fiber on diametral tensile strength of conventional and resin modified glass ionomer cements. 60 specimens in 6 groups (n=10) were prepared. In group 1 conventional glass ionomer (Fuji GC) and in group 2 resin modified glass ionomer (Fuji LC) were as control groups. In group 3 and 4 conventional glass ionomers mixed with short Polyethylene Fibers in proportion of 1 wt% and 3 wt%, respectively. In fifth and sixth groups, resin modified glass ionomer and short Polyethylene Fibers were mixed in 1 and 3% wt, respectively. Samples were prepared in a round brass mold (6.5×2.5 mm). After thermo-cycling, the diametral tensile strength of the specimens were tested and data were analyzed with ANOVA and post-hoc tests (p<0.05). Diametral tensile strength of both conventional and resin modified glass ionomer cements increased after mixing with Polyethylene Fiber (p<0.001). Also, reinforcement occurred as the mixing percentage increased from 1% wt to 3% wt in either conventional and resin modified glass ionomer (p<0.001). The Polyethylene Fiber was shown to have a significant positive influence on diametral tensile strength of two types of glass ionomers. Key words:Conventional glass ionomer, diametral tensile strength, Polyethylene Fiber, resin modified glass ionomer.
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The effect of short Polyethylene Fiber with different weight percentages on diametral tensile strength of conventional and resin modified glass ionomer cements.
Journal of Clinical and Experimental Dentistry, 2017Co-Authors: Farahnaz Sharafeddin, Seyed-ali Ghaboos, Zahra JowkarAbstract:BACKGROUND The aim of this study was to investigate the effect of Polyethylene Fiber on diametral tensile strength of conventional and resin modified glass ionomer cements. MATERIAL AND METHODS 60 specimens in 6 groups (n=10) were prepared. In group 1 conventional glass ionomer (Fuji GC) and in group 2 resin modified glass ionomer (Fuji LC) were as control groups. In group 3 and 4 conventional glass ionomers mixed with short Polyethylene Fibers in proportion of 1 wt% and 3 wt%, respectively. In fifth and sixth groups, resin modified glass ionomer and short Polyethylene Fibers were mixed in 1 and 3% wt, respectively. Samples were prepared in a round brass mold (6.5×2.5 mm). After thermo-cycling, the diametral tensile strength of the specimens were tested and data were analyzed with ANOVA and post-hoc tests (p
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The effect of short Polyethylene Fiber with different weight percentages on diametral tensile strength of conventional and resin modified glass ionomer cements
Journal of Clinical and Experimental Dentistry, 2017Co-Authors: F Sharafeddin, Seyed-ali Ghaboos, Zahra JowkarAbstract:The aim of this study was to investigate the effect of Polyethylene Fiber on diametral tensile strength of conventional and resin modified glass ionomer cements. 60 specimens in 6 groups (n=10) were prepared. In group 1 conventional glass ionomer (Fuji GC) and in group 2 resin modified glass ionomer (Fuji LC) were as control groups. In group 3 and 4 conventional glass ionomers mixed with short Polyethylene Fibers in proportion of 1 wt% and 3 wt%, respectively. In fifth and sixth groups, resin modified glass ionomer and short Polyethylene Fibers were mixed in 1 and 3% wt, respectively. Samples were prepared in a round brass mold (6.5×2.5 mm). After thermo-cycling, the diametral tensile strength of the specimens were tested and data were analyzed with ANOVA and post-hoc tests (p
Toichi Okada - One of the best experts on this subject based on the ideXlab platform.
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thermal strain of pipes composed with high strength Polyethylene Fiber reinforced plastics at cryogenic temperatures
Advances in cryogenic engineering, 1996Co-Authors: Toshihiro Kashima, Atsuhiko Yamanaka, Shigehiro Nishijima, Toichi OkadaAbstract:High strength Polyethylene Fiber (Dyneema® Fiber; hereinafter abbreviated to DF) has a large negative thermal expansion coefficient. Several kinds of pipes were prepared by means of filament winding or sheet winding method. The thermal strain or residual stress of those pipes were measured at liquid nitrogen temperature. The thermal strain was also calculated and was compared with the measured values. The circumferential thermal strain of the inner surface was found to be much different from that of outer surface. The circumferential strain changed with the ratio of inner diameter to thickness of pipes. The mean thermal strain of inner and outer surface was found to agree well with that of calculated value. It was confirmed that the negative thermal expansion can be realized even in the pipes. The design methodology of the pipes with negative thermal expansion was discussed.