Journal of the Society of Powder Technology, Japan
Online ISSN : 1883-7239
Print ISSN : 0386-6157
ISSN-L : 0386-6157
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Volume 39, Issue 4
Displaying 1-5 of 5 articles from this issue
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  • Effect of Apparent Volume Fraction of Grinding Media on Characteristics and Catalytic Activity of MoS2 Comminuted Dry in Air
    Kazumi Toda, Nobuyuki Koura, Yasushi Idemoto, Kunio Uchida, Yasunori K ...
    2002 Volume 39 Issue 4 Pages 240-246
    Published: April 10, 2002
    Released on J-STAGE: April 30, 2010
    DOIhttps://doi.org/10.4164/sptj.39.240
    JOURNAL FREE ACCESS
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    Molybdenum sulfide (MoS2) particles comminuted in a planetary ball mill dry in air at various grinding media fractions were characterized by BET surface area, element analysis, XPS, XRD and catalytic activity. Hydrogenation of 1-methylnaphthalene (1-MN) is mainly conducted to examine the catalytic activity of the comminuted MoS2 in a batch type autoclave swung at 30rpm. Relation was investigated between the characteristics of the comminuted MoS2 and apparent volume fraction of grinding media.
    Specific surface area, XRD line broadening, O/Mo measured by XPS and hydrogenation of 1-MN had the maximum and S/Mo by XPS had the minimum at the apparent volume fraction of 0.72. Catalytic activity was not explained soley by the increase in surface area of the comminuted MoS2. The catalytic activity was well correlated with S/Mo and O/Mo measured by XPS, which showed that unsaturated coordination sites of Mo are active sites for hydrogenation of 1-MN. In the experimental conditions the lattice strain of (001) and (100) of the comminuted MoS2 was almost constant, whereas the crystallite size was about 1/5 of as-received MoS2 at the apparent volume fraction of 0.72.
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  • Release Process of Enzymes from Baker's Yeast Accompanied with Inactivation by Disruption in Agitating Bead Mill
    Shoichi Morohashi, Kazuhito Adachi, Sachiko Nomura, Rieko Hase, Hideak ...
    2002 Volume 39 Issue 4 Pages 247-254
    Published: April 10, 2002
    Released on J-STAGE: April 30, 2010
    DOIhttps://doi.org/10.4164/sptj.39.247
    JOURNAL FREE ACCESS
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    Release process of enzymes from baker's yeast accompanied by inactivation was experimentally investigated by using an agitating bead mill. The enzymes examined were Alkaline phosphatase and alcohol dehydrogenase. As a result, the disruption rate of yeast was directly proportional to the product of the concentration of undisrupted yeast and agitating speed of impeller, and the disruption process of yeast was clarified by this analysis. In order to investigate the inactivation process of enzymes, the activity of enzymes within the yeast was measured using a lytic method, the results of which are not influenced by the mechanical force. In the case where there is no inactivation, the release rate of enzymes was directly proportional to the product of the activity of unreleased enzymes and agitating speed of impeller. In the case of inactivation, the release rate of enzymes was directly proportional to the product of the activity of uninactivated enzymes and agitating speed of impeller. The experimentally analyzed models based on the kinetics were found to describe well the release process of enzymes accompanied by the inactivation from baker's yeast, disrupted by the agitating bead mill.
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  • Evaluation of the Inner Structure of Fiber-Powder Composite Prepared by Different Granulation Processes Using a Drilling Tester
    Akinori Hashimoto, Munetake Satoh, Tomohiro Iwasaki, Makoto Kawasaki
    2002 Volume 39 Issue 4 Pages 255-262
    Published: April 10, 2002
    Released on J-STAGE: April 30, 2010
    DOIhttps://doi.org/10.4164/sptj.39.255
    JOURNAL FREE ACCESS
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    The local structure and strength distribution for test pieces of a composite containing fibrous material (aramid fiber) in the powder matrix (calcium carbonate and thermosetting resin) have been evaluated by using an elaborate drilling machine with a load cell and a distance sensor. The drilling resistance curve of the normal load measured under the optimal operating conditions sensitively reflected the variation of the inner structure of the composite, such as the dispersion degree of fiber, the total homogeneity, the void and crack, the packing state, the boundary of the granules, and so forth. Three types of granules prepared by different processes were molded into test pieces under the various conditions. Comparing the drilling characteristic curves with the mechanical properties of the test pieces, it was shown that the fuzzy granular-core-mixture covered with soft powder shell is a suitable raw material for molding. It was also confirmed that leaving adequate through-openings between the boundaries of granules and the internal structure of each granule is preferrable for releasing the gaseous components from the green molded test pieces up to the intermediate stage of thermal molding process.
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  • Techniques for Particle Assembly
    Fabricating Microstructures by Built-up Process
    Hiroshi Fudouzi
    2002 Volume 39 Issue 4 Pages 263-272
    Published: April 10, 2002
    Released on J-STAGE: April 30, 2010
    DOIhttps://doi.org/10.4164/sptj.39.263
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  • [title in Japanese]
    Yasunobu Kaneko
    2002 Volume 39 Issue 4 Pages 288-289
    Published: April 10, 2002
    Released on J-STAGE: April 30, 2010
    DOIhttps://doi.org/10.4164/sptj.39.288
    JOURNAL FREE ACCESS
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