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Volume 20, Issue 9
Displaying 1-10 of 10 articles from this issue
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Masatoshi CHIKAZAWA, Takafumi KANAZAWA1983 Volume 20 Issue 9 Pages 543-547
Published: September 10, 1983
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSThe packing property of CaCO3 under a fixed vapor pressure of water or methanol was studied by the tapping compression method. The compaction behavior was evaluated from the value of the final porosity (ε∞) of a powder bed formed by tapping.
In the region of low water vapor pressure, the ε∞ decreased rapidly with increase in the vapor pressure, and it took a minimum value at about 60%rH. The vapor pressure rose to about 85-90%rH, a maximum was observed, and then the value decreased markedly with an increase in vapor pressure. On the other hand, in the case of CH3OH adsorption the packing behavior resembled that of H2O adsorption, except for slight differences observed between the shapes of their ε∞-P/P0 curves.
Discussion on ε∞ change has clarified that the packing structure of CaCO3 powder varies with the height of tapping. At a low height, a powder bed consists of secondary particles. However, at a great height the secondary particle disaggregates in to primary particles due to a strong external force, and the powder bed is recognized as the packing of the primary particles.View full abstractDownload PDF (894K) -
Keijiro TERASHITA, Kei MIYANAMI, Teruo KIMURA, Masahiro MORI1983 Volume 20 Issue 9 Pages 548-553
Published: September 10, 1983
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSGreen mold sand(silica sand-bentonite-water system) has been mulled with binders by using various kneeders. The tensile process curves have been measured for the mulled mixture, the moisture content of which has been determined.
The results of this work lead to the following conclusion:
The condition of the mulling of the sands can be evaluated in terms of the tensile strength, the tensile-breakup displacement and the compression characteristics of the sands. The mixture mulled by a Simpson mill has a larger tensile strength and tensile-breakup displacement and less moisture content variation than that by a vertical cylindrical mixer (agitator). Simpson mill mulling gives a more preferable mixture. These findings agree with those of green mold sands in a real production process using a Simpson mill.View full abstractDownload PDF (912K) -
Hiroshi TSUNAKAWA1983 Volume 20 Issue 9 Pages 554-557
Published: September 10, 1983
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSIn order to predict the arch formation of coal stored in storage containers with a view to hopper design, the yield locus was measured at the initial failure of the coal tested by means of a fixed volume direct shear tester. The test material was prepared to leave a given consolidating period in the shear cell under a consolidating vertical stress. The flowability of the coal was defined as the ratio of the unconfined yield stress to the corresponding bulk density, and therefore it seemed to be in proportion to the critical span of the arch. The measured valures of flowability increased with the increase in both consolidating vertical stress and the consolidating period.
An exponential relationship was established between the flowability and the consolidating period. The relationship was expressed in terms of three parameters. The two of them, which were directly related to the saturated value of the flowability, were found to be in proportion to the consolidating vertical stress. These facts suggested that the stresses on coal which initially filled the storage container had to be correctly estimated in order to predict the minimum size of hopper outlet for ensuring the flow of coal under gravity.View full abstractDownload PDF (575K) -
Hiroyuki MURATA, Minoru WAKABAYASHI, Tadato EGUSA1983 Volume 20 Issue 9 Pages 558-563
Published: September 10, 1983
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSProblems of how to ensure a smooth flow of coals from huge silos is discussed using the flowability of 3 coals measured by Jenike's shear cell. The unconfined yield strength fc varied with the moisture content and particle size of the coals. The flow-function was not so low as to cause doming during flowing, but it became critical affer consolidation for 55 days. the Kinematic angle of friction φ′ between the coals and the walls was also critical to assure a mass flow.
These results lead to the follownig subjects for further investigation:
1) Analysis of the effect of the moisture and size of coals on fc and of the variation of φ′ with the kind of coals and wall.
2) A method of preventing fc from increasing during storage and of relieving the pressure which increases greatly during filling in huge silos and causes an increase in fc.View full abstractDownload PDF (909K) -
Yutaka TSUJI1983 Volume 20 Issue 9 Pages 564-570
Published: September 10, 1983
Released on J-STAGE: April 30, 2010
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1983 Volume 20 Issue 9 Pages 574a
Published: 1983
Released on J-STAGE: April 30, 2010
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1983 Volume 20 Issue 9 Pages 574b
Published: 1983
Released on J-STAGE: April 30, 2010
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1983 Volume 20 Issue 9 Pages 574c
Published: 1983
Released on J-STAGE: April 30, 2010
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Yoshiko HIRAI1983 Volume 20 Issue 9 Pages 575-577
Published: September 10, 1983
Released on J-STAGE: April 30, 2010
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Hiroyuki KOHAMA1983 Volume 20 Issue 9 Pages 582-585
Published: September 10, 1983
Released on J-STAGE: April 30, 2010
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