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 27, Issue 10
Displaying 1-7 of 7 articles from this issue
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  • Surface-treatment of the Ceramic Powders through Pulverization in a Reactive Atmosphere by Means of Ball Mill (2)
    Pulverization of Al2O3 in a Reactive Atmosphere by Means of Ball Mill
    Hiroshi UTSUGI, Atsushi ENDO, Noboru SUZUKI, Yutaka GO, Noriyuki BABA
    1990 Volume 27 Issue 10 Pages 664-672
    Published: October 10, 1990
    Released on J-STAGE: April 30, 2010
    DOIhttps://doi.org/10.4164/sptj.27.664
    JOURNAL FREE ACCESS
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    Al2O3 powder pulverized by a ball mill in an n-hexane, n-hexane solution of cetanol and octadecyltriethoxysilane was investigated using its dispersive property in water, its preferable dispersive property in immiscible mixed dispersive medium such as nhexane and water, and using its carbon content, surface area, infrared spectra and pyrolysis. The following were recognized (1) Al2O3 pulverized in an n-hexane solution of cetanol after 8hrs. was found to be more hydrophobic than that of unpulverized Al2O3 or Al2O3 after pulverization in an n-hexane. This is because the former dispersed in water, but dispersed in n-hexane for a mixed dispersive medium, n-hexane and water. Al2O3 pulverized in an n-hexane solution of octadecyltriethoxysilane after 32hrs. or longer was showen to be hydrophobic: (2) From their infrared spectra and pyrolysis curves, the hydrophilic, but partially bydrophobic nature of the former was confirmed to be due to the surface cetoxy group and equi-molar hydroxyl group which was formed instantaneously. Also the surface property of the latter would be caused by the formation of an octadecyldiethoxysilyl group and an ethoxy group: (3) Accordingly, it was found that effective surface-treatment had been performed by pulverization in a reactive atmosphere.
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  • Free Settling of a Cylindrical Particle in Stagnant Water
    Fumio SAITO, Kazuyoshi ARAI, Mitsuo KAMIWANO
    1990 Volume 27 Issue 10 Pages 673-679
    Published: October 10, 1990
    Released on J-STAGE: April 30, 2010
    DOIhttps://doi.org/10.4164/sptj.27.673
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    The free settling behavior of a cylindrical particles with a density ranged from 1.18 to 8.03g/cm3 in stagnant water was observed with the aid of cameras and a stroboscope. The used particles ranged from 0.3 to 1.0cm in diameter, and their size ratios of the diameter to the length were from 1.1 to 9.0. Particles having a size ratio over 1.2 sank with a periodic wobbling motion in the range of 700 to 15000 in Reynolds number. This motion was simply expressed by a harmonic equation which is composed of several parameters. The parameters were expressed as functions of the size ratio, the density ratio between the particle and water and the Reynolds number. In the regular wobbling motion of the particle, the relationship between the drag coefficient and Reynolds number showed a hysteresis loop, of which ranges of variation depend on the size of the particles, the density ratio and the Reynolds number.
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  • Analysis of Friction Properties of Non-Cohesive Mono-sized Granular Materials in Relationship to the Void Fraction
    Shin-ichiro NOMURA, Fumitoshi ITOH, Tatsuo TANAKA
    1990 Volume 27 Issue 10 Pages 680-685
    Published: October 10, 1990
    Released on J-STAGE: April 30, 2010
    DOIhttps://doi.org/10.4164/sptj.27.680
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    The friction properties represented by the angles of repose and internal friction are investigated in relationship to void fraction. A simplified packing model is developed to analyze the shear mechanism of non-cohesive monosized granular materials. Both angles are derived as a function of the void fraction and the coefficient of friction of the particle. The derived theory is confirmed reasonably well with the experiment conducted for the angle of repose for various void fractions and some reported data of the angle of internal friction.
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  • On the Particle Cut Size of Cyclone Dust Collector (Part 1)
    Imaginary Cone Model for Particle Cut Size and the Chracteristics of the Spiral Flow through Cyclones of Tangential Entry Type
    Kikaku IKEMORI
    1990 Volume 27 Issue 10 Pages 686-692
    Published: October 10, 1990
    Released on J-STAGE: April 30, 2010
    DOIhttps://doi.org/10.4164/sptj.27.686
    JOURNAL FREE ACCESS
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    In 1952, the author derived an equation for the cyclone cut size, dc, based on the concept that it can be determined by treating the aerodynamic balance of a dust particle in an “equilibrium orbit” on an imaginary cone surface the apex of which is at the apex of the conical part of a cyclone and the base of which is at the bottom of the gas outlet. The imaginary cone surface was accidentally conformed to the transitional bounday of zero vertical velocity in the cyclone under tested.
    This study was undertaken to develop more reasonable expression for the cut point by the use of a modified expression for the radius, rc, that is the radius for the which tangential velocity, u, is equivalent to the inlet velocity, uo, as well as the expression for the power, n, of r in the tangential velocity distribution equation, urn=uorcn=constant. For this purpose., flow measurements as well as dust collection experiments were conducted with geometrically similar cyclones of a tangential entry type, and the experimental equations for n and rc were obtained as follows:
    n=0.82(Reu/104)0.18 for 6×103<Reu<3×104
    and n=0.16(Reu/104)1.5 for Reu<6×103
    where Reu is the spiral flow Reynolds number expressed as
    Reu=[Do/H][Douoρ/μ],
    furthermore for cut radius
    rc=[9/4√Reu]1/nD1/2
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  • Fractal Dimension and its Application for Powder Technology
    Michitaka SUZUKI
    1990 Volume 27 Issue 10 Pages 693-699
    Published: October 10, 1990
    Released on J-STAGE: April 30, 2010
    DOIhttps://doi.org/10.4164/sptj.27.693
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  • [title in Japanese]
    Ken-ichi SUGIMORI
    1990 Volume 27 Issue 10 Pages 707-708
    Published: October 10, 1990
    Released on J-STAGE: April 30, 2010
    DOIhttps://doi.org/10.4164/sptj.27.707
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  • [title in Japanese]
    Yoshinobu MORIKAWA
    1990 Volume 27 Issue 10 Pages 709-711
    Published: October 10, 1990
    Released on J-STAGE: April 30, 2010
    DOIhttps://doi.org/10.4164/sptj.27.709
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