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 16, Issue 4
Displaying 1-11 of 11 articles from this issue
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  • [title in Japanese]
    Masafumi Arakawa
    1979 Volume 16 Issue 4 Pages 172
    Published: April 10, 1979
    Released on J-STAGE: April 30, 2010
    DOIhttps://doi.org/10.4164/sptj.16.172
    JOURNAL FREE ACCESS
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  • Shearing-Failure Process of Powder Bed in a Direct Shear Tester with Constant Vertical Load
    Kei MIYANAMI, Keijiro TERASHITA, Tohru OZAKI, Takeo YANO
    1979 Volume 16 Issue 4 Pages 173-178
    Published: April 10, 1979
    Released on J-STAGE: April 30, 2010
    DOIhttps://doi.org/10.4164/sptj.16.173
    JOURNAL FREE ACCESS
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    Shearing process diagrams (the relations of shearing stress and vertical dilating strain to horizontal shearing strain) for eleven varieties of powders have been obtained to analyze the shearing-failure behaviors of the powder beds by a direct shear tester with constant vertical load. A macroscopic model has been presented to estimate the average critical void fraction and thickness of shearing zone under flowing condition in the circular shearing cell of the tester. It has been shown that the average critical void fraction and thickness are characteristic of the powders tested under identical experimental conditions.
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  • Computer Simulation of the Slow Settling of Spherical Particles in a Cylindrical Container: A Modified Tory's Method
    Keishi GOTOH, Toshifumi CHIBA
    1979 Volume 16 Issue 4 Pages 179-183
    Published: April 10, 1979
    Released on J-STAGE: April 30, 2010
    DOIhttps://doi.org/10.4164/sptj.16.179
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    Tory's Computer simulation of the slow settling of spherical particles into a randomly packed bed is modified: After removing the periodical boundary of the wall and the randomly packed bed at the bottom, a new boundary condition of a cylindrical container is introduced. In order to identify the position of the particles in the container, the coordinate of cubical lattices of side 1.0 sphere diameters is devised and the particle numbers are stored in the corresponding three-dimensional array of the computer memory. This saves considerable amount of the necessary memory and the computer program becomes simple, comparing with Tory's method where small lattices of side 0.5×1.15 sphere diameters are used. The average volume fractions of the particles without the wall effect are 0.582 for uniform feeding of the particles over the cross-section of the container and 0.612 for the particle feeding from the center. In the latter, the bottom floor of the container affects the particle arrangement as far as 13 particle layers into the interior. For the other cases, however, the wall effects are on two particle layers only. Although the packing structures obtained from the computer simulation cannot be actual, experimental results, the data may be able to play important roles in the theoretical analysis.
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  • On the Bottom Pressure Distribution of the Bulk Materials Piled with the Angle of Repose
    Tomosada JOTAKI, Ryuichi MORIYAMA
    1979 Volume 16 Issue 4 Pages 184-191
    Published: April 10, 1979
    Released on J-STAGE: April 30, 2010
    DOIhttps://doi.org/10.4164/sptj.16.184
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    As previously pointed out by several papers, it is seen that the bottom pressure distribution of the bulk materials in a cylindrical vessel with a flat bottom changes greatly according to the size of the particles, the size of the cylindrical vessel, the filling method and the filling speed. But the mechanism which generated the bottom pressure distribution has not been explained in full.
    In this paper, the authors measured on the vertical bottom pressure distribution of the bed piled with the angle of repose on a flat measuring table and in a cylindrical vessel, to ascertain the formation of the arching in the bed, and discussed.
    The results of the considerations are as follows.
    (1) Arching phenomena generate to center part in the bed piled with angle of repose.
    (2) Some weights of the center part dropped according to the arching are supported by the peripheral part in the bed piled.
    (3) The mechanism of the arching is explained by formula of (6) approximately.
    (4) The bottom pressure of the center part dropped is independent of the existence of the cylindrical vessel.
    (5) In the case of the angle of repose with the cylindrical vessel, the vertical weight adding on the wall in the cylindrical vessel is shown by following a formula.
    Ww=W4-(W3-W1)
    where, W4, W3, W1 is shown in Fig. 16.
    (6) The bottom pressures of the leg of arching become higher than calculated values by γh for the bed piled, and a scope of the leg is about two times of arch redius.
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  • Estimation of an Adhesion Force among Particles in Graphite Powders by Electric Resistance and Effect of Relative Humidity on the Force
    Yukio FUJIHARA, Yoshihide YOSHIMURA
    1979 Volume 16 Issue 4 Pages 192-197
    Published: April 10, 1979
    Released on J-STAGE: April 30, 2010
    DOIhttps://doi.org/10.4164/sptj.16.192
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    The measurement of the amount of adsorbed water on graphite powders (mean diameter; 16 micron), W and its electric resistance, Ram has been carried out changing relative humidity step by step.
    The availability of the electric resistance method in estimating adhesion force among particles in the powder bed and the effect of humidity for the estimates has been studied.
    It was found with the relative humidity, RH changed from 30 to 95% that the Ram decreses as W increass.
    The change patterns of these values for the RH are the same, i. e, each Ram vs RH cuve has a break point in spite of its parameters change (Compression and Temperature).
    The availability of this method clarified by comparison with other method.
    It is concluded that the Ram closely related to the W, and the change rate of on adhesion force for the RH is differ with befor and after break point.
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  • The Effect of the Dimensions of Test Cell on the Result of Shear Test of Powder Bed
    Mitsuaki HIROTA, Toshio OSHIMA, Shinya HASHIMOTO
    1979 Volume 16 Issue 4 Pages 198-206
    Published: April 10, 1979
    Released on J-STAGE: April 30, 2010
    DOIhttps://doi.org/10.4164/sptj.16.198
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    A direct shear tester with normal stress of the pressure differences which caused by air stream passed through the powder bed was made on an experimental basis. This tester is characterized that the powder bed are compressed uniformly even in the small size cell and the shear cells of several dimensions can be fitted up. As the results of shear test, it recognized that the dimensions of the shear cell effected on remarkably τcrit. and τmax. and the suitable range about the size of the cell existed. Since this suitable size of the cell are very small, it is difficult to use of the widly used shear tester which compress the powder bed with a piston rod. Packing structure on the shearing face of the powder bed shift with progress of shearing and the value of τmax. contain the variation of packing structure of the shearing faces. Consequently, the results of τmax. are affected slightly by the consolidating conditions and sensibly by the flowability of test powder and the shearing conditions. On the contrary, the results of τcrit. contained sensibly the variation of the consolidating conditions.
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  • The Effect of Lubricant during Compaction of Powders
    Changes of Mechanical Properties
    Jutaro OKADA, Yoshiko HIRAI
    1979 Volume 16 Issue 4 Pages 207-211
    Published: April 10, 1979
    Released on J-STAGE: April 30, 2010
    DOIhttps://doi.org/10.4164/sptj.16.207
    JOURNAL FREE ACCESS
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    The compaction behaviours of the potassium chloride powders were studied with or without 2.0% magnesium stearate. Their mechanical properties, namely the stress-strain in the one-dimensional compression, the yield locus and the wall yield locus, were obtained experimentally. The coefficients of internal friction and that of wall friction decreased by addition of magnesium stearate, especially for the latter it was remarkable. Using these data, pressure-transmission-ratios (PL/PU) were calculated theoretically, and compared with experimental results.
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  • Measuring Method of Stick-Slip Phenomena of Singing Sand
    Masao SAWAJI, Hideaki KITANI, Shigeki MATSUI, Eiji TOBA
    1979 Volume 16 Issue 4 Pages 212-219
    Published: April 10, 1979
    Released on J-STAGE: April 30, 2010
    DOIhttps://doi.org/10.4164/sptj.16.212
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    The Properties of Singing sands such as particle shape, size distribution, material and so forth have been investigated widely in many fields. We believe that the mechanism of sound generation is the same Stick-Slip phenomena as scrooping sound of silk.
    We have devised a particular trial apparatus, the purpose of which is to explain the growth mechanism of sand singing.
    This apparatus continually measues and records Stick-Slip phenomena. We measured a few singing sands and silent sand with this apparatus. S-S characteristics of singing sands under slow press in process are as follows.
    (a) General compressibility was large in comparison with envelope curve.
    (b) But, every subsidence of sands surface with stick stage was rather small.
    (c) Each slip length and slip energy was promoted from position to position.
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  • [title in Japanese]
    [in Japanese]
    1979 Volume 16 Issue 4 Pages 220-225
    Published: April 10, 1979
    Released on J-STAGE: April 30, 2010
    DOIhttps://doi.org/10.4164/sptj.16.220
    JOURNAL FREE ACCESS
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  • [title in Japanese]
    [in Japanese]
    1979 Volume 16 Issue 4 Pages 225-226
    Published: April 10, 1979
    Released on J-STAGE: April 30, 2010
    DOIhttps://doi.org/10.4164/sptj.16.225
    JOURNAL FREE ACCESS
    Download PDF (326K)
  • [title in Japanese]
    [in Japanese]
    1979 Volume 16 Issue 4 Pages 226-227
    Published: April 10, 1979
    Released on J-STAGE: April 30, 2010
    DOIhttps://doi.org/10.4164/sptj.16.226
    JOURNAL FREE ACCESS
    Download PDF (280K)
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