粉体工学会誌
Online ISSN : 1883-7239
Print ISSN : 0386-6157
ISSN-L : 0386-6157
23 巻, 12 号
選択された号の論文の17件中1~17を表示しています
  • 大島 敏男
    1986 年 23 巻 12 号 p. 831
    発行日: 1986/12/10
    公開日: 2010/04/30
    ジャーナル フリー
  • 神谷 秀博, 岸 伸展, 椿 淳一郎, 神保 元二
    1986 年 23 巻 12 号 p. 832-838
    発行日: 1986/12/10
    公開日: 2010/04/30
    ジャーナル フリー
    As was reported by the authors, it was recognized that the tensile strength of a powder bed prepared by compressive creep was increasing with time. This phenomenon is important in practical operations such as the storeage of powder.
    In the present work, to more quantitatively analyze this phenomenon, the transitional behavior of the tensile strength and stress-deformation curve are measured. The powder beds are prepared by three kinds of compressive histories, that is, creep, recovery of creep, and relaxation. In order to consider the mechanism of this phenomenon, the bottom stress distribution is measured during compressive histories. Materials used are Kanto loam, fused alumina, lactose and limestone powder.
    As results, it is recognized that the transitional processes of the tensile strength the depend on the preparations. In the case of creep and the recovery of creep and unlikely relaxation, the tensile strength is increasing with time. On the other hand, it is found that the bottom stress distribution tends slightly to become homogeneous for creep and recovery. From these results, the mechanism of increasing tensile strength with time is explained qualitatively by the homogenization of the bottom stress distribution.
  • 大内山 紀男, 田中 達夫
    1986 年 23 巻 12 号 p. 839-844
    発行日: 1986/12/10
    公開日: 2010/04/30
    ジャーナル フリー
    Two existing theories for porosity estimation from particle size distribution were examined by using past experimental data from a binary mixture. In addition, porosity computations by the authors' recent theory were carried out with mixtures of both Gaussian and log-normal size distributions. Several discussions presented in the paper suggest that the authors' theory can be applied widely up to the mixtures of the solid particles the sizes of which are remarkably different.
  • 中川 勝文, 古内 正美, 三輪 和利, 後藤 圭司
    1986 年 23 巻 12 号 p. 845-849
    発行日: 1986/12/10
    公開日: 2010/04/30
    ジャーナル フリー
    The capillary rising phenomenon is controlled by the complicated intersticial structure in the packed bed. In order to investigate the correlation between the capillary rise and the intersticial structure of a packed bed, the capillary rising velocity is measured for a packed bed of equal sphere size.
    The experimental results show that the effective suction head for capillary rise depends on the intersticial structure of the bed. The liquid rises through the remaining air cavities in the packed bed. The relationship between the retained air volume and the particle volume fraction is explained from the pervious theory of the pore size distribution in the packed bed.
  • 長尾 高明, 畑村 洋太郎, 竹内 孝次, 中島 信行
    1986 年 23 巻 12 号 p. 850-856
    発行日: 1986/12/10
    公開日: 2010/04/30
    ジャーナル フリー
    Two-way stress cells which can measure small normal and frictional stresses of granular materials on a wall are newly developed. With these cells, the stress distributions of granular materials (silica sand and millet grain) piled conically on a plate are measured and compared with the results of theoretical analysis. The results are as follows:
    1) The maximum normal stress occurs at a distance of a quarter of the outer radius of the cone of the pile, which is about (0.7-0.8)γH, where γ is the apparent specific gravity and H denotes the height of cone.
    2) The normal stress at the center is rather small, about (0.4-0.6)γH.
    3) The maximum frictional stress also occurs at the same position with maximum normal stress.
    4) Theoretical analysis gives a maximum normal stress of 0.5γKH(√2/K-κ-√κ)2/(1-κK)2 at a radius r=H/√κ(2/K-κ) and a normal stress at the center γH[1-K2(f-κ)(2/K-κ-f)/(1-κK)2], where κ denotes the internal friction coefficient, and K denotes the friction coefficient between granular material and the surface of plate. f is given by the formula (40). This agrees well with the experimental result.
  • 岡本 廣祐
    1986 年 23 巻 12 号 p. 857-864
    発行日: 1986/12/10
    公開日: 2010/07/01
    ジャーナル フリー
    The purpose of this investigation is to obtain a basic knowledge of the characteristics and mechanism associated with the generation of a pressure wave by granular materials during mass flow and deformation. The theoretical estimations are made of the amplitude and the natural frequency of the pressure wave due to local sudden changes in strain produced under large applied stresses. The estimations have been compared with the experimental results and a reasonable agreements were found.
    The following are deduced from them:
    1) The dynamic pressure which radiated from an edge of the sliding plane is estimated by a factor of 1.5 times its initial pressure.
    2) The period of the pressure wave is proportional to the radius of wave origin and is inversely proportional to the velocity of the pressure wave.
    3) The level value of a peak at the frequency domain of spectrum decay f-2 of the pressure wave spectrum is proportional to the flow-rate.
    4) The natural frequency and specturm decayf-r at the spectrum of pressure wave depend on the dissipative mechanism of energy.
  • 加熱混練に伴なう樹脂変質の影響について
    高橋 実, 鈴木 傑
    1986 年 23 巻 12 号 p. 865-870
    発行日: 1986/12/10
    公開日: 2010/04/30
    ジャーナル フリー
    The mixing torque of polypropylene (PP) and polystyrene (PSt) decreased monotonously with the increase in mixing time at 453K, whereas that of polyethylene (PE) decreased up to about 10min and increased afterwards. Fluidity after mixing was improved for PP and PSt, but it deteriorated for PE.
    The behavior of an alumina-resin mixture with a high solid volume content of 60% was similar to PE during the initial stage of mixing. This, however, could be attributed to the agglomeration of alumina powders. Addition of a nonionic surfactant lead to smooth mixing and also improved the flow characteristics of this system. The mixing characteristics in the alumina-resin-surfactant system reflected the properties of resins more clearly than in the alumina-resin system. Thus, an apparent constant torque after a sufficient mixing time could be observed only in a special blending ratio of PE, PP and PSt.
  • 水上 俊一, 前花 忠夫, 村田 博之
    1986 年 23 巻 12 号 p. 871-876
    発行日: 1986/12/10
    公開日: 2010/04/30
    ジャーナル フリー
    A method for increasing the production rate of iron ore sintering is discussed, and its operational results are reported. The volume of air passing through the raw material bed determines the combustion speed of coke breeze. Therefore, the production rate of a sintering machine depends largely upon the gas permeability of the bed. Gas permeability is affected by particle size segregation in the bed that results from raw material feeding to the sintering machine.
    An optimum feeding chute profile for segregation was calculated by assuming that the horizontal velocity of the discharging material is the dominant factor in segregation. The effect of segregation on permeability was also calculated by Ergun's equation. The calculations were experimentally confirmed in a test model with a height equal to that of a fullscale chute but with the width reduced to 1/4.
    Actual field operation with the new design showed an increase in the rate of production from 2.1t/(h·m2) to 2.2t/(h·m2), and a 17% reduction in the amount of quick lime required.
  • 鈴木 和夫, 桑原 好孝
    1986 年 23 巻 12 号 p. 877-881
    発行日: 1986/12/10
    公開日: 2010/04/30
    ジャーナル フリー
    Si3N4 powders, of which particle sizes were in the order of micron meter, were compacted at high pressure, and the porosity and representative pore size were examined. It was found that particle size distribution affected the porosity of the packed body although the effect of aggromeration was important. On the other hand, the representative pore sizes of the packed body were related to the specific surface area of the powder.
  • 湯 晋一, 中村 佐三, 古沢 丈晴
    1986 年 23 巻 12 号 p. 882-888
    発行日: 1986/12/10
    公開日: 2010/04/30
    ジャーナル フリー
    We have measured the shear stress-strain and the vertical normal strees-strain relations by using a shear and compressive load tester.
    As the result, we found that G=dτ/dγ (modulus of elasticity in shear) depends upon the particle or aggregate configuration of the powder, and the value of G is much smaller than the value of the mother material. For the compressive load test, the adhesive powder becomes harder with increase in stress, while the non-adhesive powder yields more easily.
    It is important to consider these characteristics through the process of finding the powder constitutive equation.
  • 丹野 浩一, 八嶋 三郎
    1986 年 23 巻 12 号 p. 889-895
    発行日: 1986/12/10
    公開日: 2010/04/30
    ジャーナル フリー
    The influence of packing fraction on the over pressures has been studied at a rate of charging of about 0.04-47.19Kg/min, using atomized metal powders (Cu and Ni-Cr alloy) at a mean particle diameter range of 44.0.-127.0μm on a cylindrical bin sitting on its flat bottom.
    The value of the packing fraction differed with the charging processes and rate. Especially, in the case of the dispersive charge, it in creased about 8% for powders larger than 89.5μm in mean particle diameter. As the packing fraction increased about 8%, the static wall pressure (Ps) was almost doubled, and the dynamic wall pressure (Pd) was markedly increased. The types of flow-patterns in the bin were determined by mass-flow when the packing fraction was smaller than 63.7% and by transition-flow when it was larger than 66.5%.
    The results indicated that the over pressure increase as the flow-pattern types changed from mass-flow to transitional-flow due to decrease in charging rate.
  • 村田 博之, 若林 稔
    1986 年 23 巻 12 号 p. 896-899
    発行日: 1986/12/10
    公開日: 2010/04/30
    ジャーナル フリー
    Wall pressures were measured during coal discharge from a hopper with a volume of 80m3. Power spectra of pressure fluctuations showed higher amplitudes distributed among frequencies below 10-2Hz. The equation of motion was used to determine a stress-strain relationship of materials in a hopper that explains the cause of pressure fluctuations and their low frequencies.
    A stress-strain relationship was found by analyzing stick-slip motion during the failure of materials, and this was illustrated by a hysteresis loop consisting of two different paths for compression and elongation.
  • 後藤 圭司
    1986 年 23 巻 12 号 p. 900-904
    発行日: 1986/12/10
    公開日: 2010/04/30
    ジャーナル フリー
  • 荒川 正文
    1986 年 23 巻 12 号 p. 905-910
    発行日: 1986/12/10
    公開日: 2010/04/30
    ジャーナル フリー
  • 1986 年 23 巻 12 号 p. 911-914
    発行日: 1986/12/10
    公開日: 2010/04/30
    ジャーナル フリー
  • 粉体の構造と性質
    大島 敏男
    1986 年 23 巻 12 号 p. 915-928
    発行日: 1986/12/10
    公開日: 2010/04/30
    ジャーナル フリー
  • 1986 年 23 巻 12 号 p. 929-930
    発行日: 1986/12/10
    公開日: 2010/04/30
    ジャーナル フリー
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