Masatoshi Shioya; Takashi Kajikawa; Kuniaki Takahashi; Yoshiki Sugimoto
Abstract
Development of carbon fibers from alternative precursory materials through new production processes is a recent topic of active research. In such a research, the maximum available tensile strength, i. e. the tensile strength which will be achieved after elaboration to suppress defect formation during ...
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Development of carbon fibers from alternative precursory materials through new production processes is a recent topic of active research. In such a research, the maximum available tensile strength, i. e. the tensile strength which will be achieved after elaboration to suppress defect formation during production process, is the matter of great concern. We have developed a method for determining this strength through the tensile test on a single fiber after introducing an artificial notch. In the present paper, this method has been refined. By using the refined method, the distribution of the maximum available tensile strength at various radial positions has been measured for a polyacrylonitrile-based carbon fiber. The difference between the maximum available tensile strength and the strength predicted using other methods such as those based on the fracture toughness and the fiber-length dependence of the tensile strength has also been discussed.
K. K. Satapathy;F. Khan
Abstract
The mechanoluminescence (ML) of γ-irradiated Anchor ZnAl2O4: Dy phosphor has been studied. ZnAl2O4 samples having different concentrations of Dy were prepared by solution combustion technique by using hydrazine as a fuel. ML was excited impulsively by dropping a load onto the sample. Two distinct ...
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The mechanoluminescence (ML) of γ-irradiated Anchor ZnAl2O4: Dy phosphor has been studied. ZnAl2O4 samples having different concentrations of Dy were prepared by solution combustion technique by using hydrazine as a fuel. ML was excited impulsively by dropping a load onto the sample. Two distinct peaks have been observed in the ML intensity versus time curve. Maximum intensity is obtained for 0.1 mol% of Dy doped ZnAl2O4 phosphor. ML spectra of the phosphors show two distinct peaks around 482 nm and 585 nm which is characteristic emission of Dy 3+ . It is also observed that the ML intensity of the samples increases almost linearly with increasing mass of the sample and gamma ray doses given to the sample. Experimental results suggest that the ML excitation is related to the movement of dislocation with defect centres and it may be used for dosimeter applications.
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