Journal of the Society of Powder Technology, Japan
Online ISSN : 1883-7239
Print ISSN : 0386-6157
ISSN-L : 0386-6157
Volume 32, Issue 5
Displaying 1-6 of 6 articles from this issue
  • Takamichi YAHIRO
    1995 Volume 32 Issue 5 Pages 300-310
    Published: May 10, 1995
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
    The asymmetric wall pressure on the parallel portion of a silo due to the segregation and the inclination of bulk density caused by throwing bulk from the ends of silo wall is investigated. The remarkable asymmetry of wall pressure is produced on the walls between the throwing bulk and the far sides under dynamic conditions, and the magnitude of the maximum asymmetric pressure comes to about 50% of Janssen's static wall pressure in the parallel portion. The position in height that produced the maximum asymmetric pressure is a relatively high position for a bulk solid the bulk density of which is large or in which the coefficients of the wall and internal frictions are samll. A node of asymmetric pressure does not arise in a bulk solid in which the coefficients of the wall and internal frictions are small but the coefficients of which are large.
    The asymmetry of the wall pressure is produced owing to the existence of a descrepancy in the direction of the major principal stress on the walls between the throwing bulk and the far sides. The wall pressures at a high position on the far side and at a low position on the throwing side increase in bulk solid in which the coefficients of the wall and internal frictions are large. In a bulk solid in which the coefficients of the wall and internal frictions are small, the wall pressure on the far side increases at every position in height.
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  • Sound Absorption Characteristic and Sound Velocity
    Yuzo OKUDAIRA, Hideyuki ANDO, Munetake SATOH, Kei MIYANAMI
    1995 Volume 32 Issue 5 Pages 311-318
    Published: May 10, 1995
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
    The sound absorption coefficients and sound velocity of various powder beds were measured in the frequency range of 200Hz to 2kHz. The powder beds were comprised of classified powders having mean particle diameters from 53 to 300μm. For the powder beds consisting of smaller particles, the sound absorption coefficients showed distinct peaks due to the excitation of normal vibration modes of the powder bed. In the frequency range in which sound absorption peaks appear, the sound velocity has almost on frequency dependency, and sound energy is dissipated mainly by the interaction of vibrated particles. As particles with larger diameters were used, these peaks decreased in amplitude, but the level of sound absorption increased in the high frequency range. In this frequency range, sound velocity increases according to frequency, and sound energy is dissipated mostly by the viscosity of the air in the pores.
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  • The Mechanism of Convective Mixing
    Kunio SHINOHARA, Sachiko SUWA
    1995 Volume 32 Issue 5 Pages 319-325
    Published: May 10, 1995
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
    A mechanism for the continuous convective mixing of dry powders is proposed in order to design a new type of static powder mixer using fluctuating air. Separate layers of a binary mixture are fed into the upper inlet of the mixer and are mixed with horizontal fluctuating air alternatively along the vertical side walls.
    As a result of the simulation of single particle movement, it was found that the degree of mixing depends on the mixer dimensions, such as the width of the powder inlet and the interval of the air inlets, and on the operating conditions, such as the particle-falling velocity, the maximum velocity of fluctuating air and the fluctuation frequency. This suggests that it may be possible to control the degree of mixing by means of the proposed powder mixer with fluctuating air.
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  • Noriyuki YAMADA, Eiichi ABE, Hideharu HIROSUE
    1995 Volume 32 Issue 5 Pages 326-329
    Published: May 10, 1995
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
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  • Yoshihiro TAGUCHI
    1995 Volume 32 Issue 5 Pages 330-336
    Published: May 10, 1995
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
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  • Chikao KANAOKA
    1995 Volume 32 Issue 5 Pages 347-351
    Published: May 10, 1995
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
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