KAGAKU KOGAKU RONBUNSHU
Online ISSN : 1349-9203
Print ISSN : 0386-216X
ISSN-L : 0386-216X
Volume 19 , Issue 1
Showing 1-22 articles out of 22 articles from the selected issue
  • Masafumi Matsumoto, Toshikiyo Hashimoto, Katsuhide Murata, Shigeo Goto
    1993 Volume 19 Issue 1 Pages 1-6
    Published: January 10, 1993
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The weight of carbon whiskers formed by pyrolysis of benzene was decreased at a temperature higher than 600°C by oxidation under air atmosphere. Oxidation of carbon whiskers with carbon dioxide was a reaction of first order and its activation energy was 145 kJ/mol. Oxidation began in the turbostatic layer on the outside of carbon whiskers, and then a “graphite-like” domain inside the carbon whiskers was exposed. After oxidation treatment functional groups of ether, carbonyl and lactone were added to the surface of the carbon whiskers.
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  • Shinzo Nishikawa
    1993 Volume 19 Issue 1 Pages 7-12
    Published: January 10, 1993
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Partial polymerization in vertical concentric cylinders with the inner one rotating was investigated. An empirical equation correlating conversion with polymerization time for the bulk polymerization of methyl methacrylate was obtained and the rate equation was derived.
    An equation incorporating overall heat transfer coefficient and reaction rate constant was derived to determine annulus design facters and a calculation chart was prepared to select operation conditions. To verify the operation of this system, polymerization reaction was conducted in a test reactor of concentric rotating cylinders. Calculated conversions were in good agreement with observed values, with a mean error of 0.28 %.
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  • Yoshihisa Mizuno, Keijiro Terashita, Kei Miyanami
    1993 Volume 19 Issue 1 Pages 13-20
    Published: January 10, 1993
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    In continuous kneading, for stable -state production the feeder that feeds raw material and the heater that heats objective material must be controlled with consideration of the dynamics of the kneader.
    In this paper, kneader dynamics was studied by examining responses in the realtime region and the frequency region, between variation of feed rate or kneading temperature and variation of kneading torque, which represents the state of flow of objective material. From this analysis, it was found that the response in the low -frequency region is most remarkable. The results showed that kneading can be performed in stable state by avoiding variation of feed rate and heating. Continuous kneading of electrically conductive resin was carried out with control of the feeder that took the dynamics into consideration. It was confirmed that variation of electrical conductivity of the electrically conductive resin could be made small, and that the effectiveness of control was remarkable when the flow state of objective material in the kneader was plug flow.
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  • Yoshihisa Mizuno, Keijiro Terashita, Kei Miyanami
    1993 Volume 19 Issue 1 Pages 21-29
    Published: January 10, 1993
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    To determine the dispersion state of filler quantitatively in an electrically conductive resin, the image of the dispersion state on a cross section of the resin was fed into the personal conputer by image processor and the fractal dimension of dispersion state based on area ratio was calculated. The fractal dimensions was calculated for images of sixteen kinds and were compared each other. The results show that the fractal dimension was effective in quantitative representation of the dispersion state. We also tried to evaluate the electrical conductivity of electrically conductive resin with the fractal dimension. Electrical conductivity of electrically conductive resin could be related to the product of fractal dimension and length of filler. Prediction of the dispersion state was also tried by comparing the fractal dimension and the dimensionless number calculated from the data obtained during kneading.
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  • Shigeyuki Tateno, BohYoh Shibata, Yoshifumi Tsuge, Hisayoshi Matsuyama
    1993 Volume 19 Issue 1 Pages 30-40
    Published: January 10, 1993
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The accuracy of the algorithm for fault diagnosis by use of a signed digraph and a 5-range pattern has been improved, utilizing the fact that the deviation of the state variable from its normal value caused by system failure damps as the distance between the variable and the origin of failure increases. Furthermore, a method of evaluating the accuracy of this algorithm is proposed, utilizing the greatest set of candidates. The algorithm's accuracy is compared with that of other algorithms by fault diagnosis in tank-pipeline systems.
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  • Kyu Murata, Kyoko Yamamoto, Hideo Kameyama
    1993 Volume 19 Issue 1 Pages 41-47
    Published: January 10, 1993
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A thin-layered catalyst supported on a therino-conductive metal plate is one of the ideal types of catalysts which make it possible to design a compact reactor. A reactor equipped with this type of catalyst can serve as a heat exchanger since the catalyst is expected to exhibit high thermal conductivity and low pressure loss. A Pt/Al2O3/Al-plate type catalyst was prepared by anodic oxidation of a commercial aluminum plate (to produce alumina film as a catalyst support), followed by hotwater treatment in chloroplatinic acid solution (to increase BET surface area of the alumina film and simultaneously to impregnate Pt as a catalyst species). The conditions for preparing a catalyst film of any thickness under 30 μm was established. The amount of Pt supported per BET surface area of alumina was 170-180 g/m2, fi which corresponds to 3 wt% of alumina, and the dispersion of Pt was around 0.5, regardless of the thickness of the alumina film. Catalyst with 30 μm of alumina film showed a constant reaction rate per apparent surface area of 3.5 mol/ (h·m2) for cyclohexane dehydrogenation at C6H12/N2 = 1/10, 1 atm and 200 °C for 130 hours.
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  • Yong Chen, Hitoki Matsuda, Masanobu Hasatani, Kiyoshi Kondo, Ichiro Na ...
    1993 Volume 19 Issue 1 Pages 48-54
    Published: January 10, 1993
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The combustibility of finely powdered fly ash A and B, discharged from a combustion furnace operated at 1673 K and a fluidized-bed combustor at 1123 K, respectively, was investigated by applying nonisothermal reaction analysis with a thermo-gravimeter. The combustion experiments were carried out in an atmosphere of air flow under the following conditions : sample size < 37μm, heating rate 1-1000 K/min, and temperature up to 1173K. The results obtained are as follows.
    1) When heating rate is below 2 K/min the combustion becomes reaction-controlled; when it is above 700 K/min the combustion becomes diffusion-controlled.
    2) The combustion reaction parameters and effective diffusivity of oxygen in ash were fly ash A : E 70.1 (kJ/mol), A=0.71 (Us kPa), Dc =1.66× 10-5 (cm2/s)
    fly ash B : E = 82.0 (kJ / mol), A=13.3 (1/s kPa), Dc= 1.94×10-5 (cm2/s)
    3) The combustibility of fly ash A is sampller than that of char A. It was observed that part of the unburned carbon in fly ash A was converted to graphite.
    4) The combustibility of fly ash B is slightly greater than that of char B. This difference was considered to be caused by the difference in specific surface area of unburned carbon between char B and fly ash B.
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  • Yoshiyuki Endo, Yasuo Kousaka, Yasunobu Nishie
    1993 Volume 19 Issue 1 Pages 55-61
    Published: January 10, 1993
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Adhesion force arising from a liquid bridge formed between two spheres has been theoretically analyzed on the basis of the Laplace equation, and it was found that 1) adhesion force could be expressed as a resultant of the capillary force in the bridge and a component of the force of surface tension in the direction of separating two particles, and 2) adhesion force between two identical spheres was theoretically related to liquid bridge profiles obtained from solution of the Laplace equation. In the experiments, results of tensile strength tests of water bridges formed between two identical glass spheres and convex lenses were found to be in good agreement with the theoretical results. In combining the results thus obtained with our previous theory, in which liquid bridge profiles were determined by surrounding humidity and solute concentration in the bridging liquid, it was finally found that the adhesion force arising from a liquid bridge between two spheres could be evaluated as a function of surrounding humidity and soluble impurity content in the liquid.
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  • Tatsuo Kanki, Susumu Harada, Tsuyoshi Asano, Hiromitsu Maki, Wataru Eg ...
    1993 Volume 19 Issue 1 Pages 62-68
    Published: January 10, 1993
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Axial pressure distributions in a screw-grooved molecular pump were analyzed, using the pressure-smoothing theory applying numerical solutions of the BoltzmannKrook equation for flow of a rarefied gas in a rectangular groove faced with a moving plate, and relations among attainable pressure, evacuation speed, and rota rotation speed were made clear. A screw-grooved pump was designed for tests to investigate the evacuation characteristics. Attainable pressures and evacuation speeds at some typical rough pressures were measured against rota rotation speed, and their results were compared with numerical ones from the theory. Dependencies of gas species on evacuation characteristics were also made clear.
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  • Atsushi Ikari
    1993 Volume 19 Issue 1 Pages 69-75
    Published: January 10, 1993
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    To investigate the behavior of impurities in batch rectification of aqueous ethanol solution, a mathematical model was constructed by considering the conventional assumptions in distillation calculation and also in the characteristics of a trace component. The model includes some adjustable parameters that can be used for adaptation.
    A set of equations were derived from the mass balances around a still, a typical plate and a distillate accumulator. It can be solved numerically by a personal computer. The distillation curves of ethanol and trace components can be obtained.
    The results of a test calculation show that the present method is useful in analysing the batch rectification in the production of distilled spirit.
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  • Jun Fukai, Hisayuki Orita, Takayuki Nejime, Kazutaka Saruwatari, Osamu ...
    1993 Volume 19 Issue 1 Pages 76-82
    Published: January 10, 1993
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Temperature dependency of the effective thermal conductivity of isotropic formed green carbon during carbonization is estimated of the basis on that of packed green carbon before forming. The formed green carbon is regarded as a porous material containing micropores. The packed green carbon during carbonization successively changes its structure from that of a packed bed of particles initially to that of a porous body after going through that of a consolidated body. The thermal conductivity of gaseous tar, which is necessary to determine that of gas phase, is obtained from some physical properties of the gas species of which liquid tar is composed. Porosity of the specimen and molar fractions of the gases released by pyrolysis are experimentally determined.
    The effective thermal conductivity is measured by using the hot-wire method while the specimen is heated from room temperature to about 1000 K at a constant heating rate of 1 K /min. Estimated effective thermal conductivity for two kinds of formed green carbons agrees well with the respective measured values over a wide range of temperature.
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  • Fujio Watanabe, Yoshito Watabe, Hitoshi Katsuyama, Jun Kozuka, Masanob ...
    1993 Volume 19 Issue 1 Pages 83-90
    Published: January 10, 1993
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    As a step in the application of water vapour adsorption to the heat pump (AHP), the exo - and endothermic characteristics accompanying adsorption/desorption of water vapour in adsorbent packed beds of the external cooling/heating type were studied both experimentally and theoretically. Two adsorbents, structural active carbon and silica gel, which were shown to be usable as the heat storage material in the AHP by experimental results for adsorption equilibrium and rates, were for packed-bed experiments.
    The trend of experimental results with both adsorbents agrees well with computer simulation under closed -system, one -component, non -isothermal conditions. In addition, the time-changes of amount adsorbed, temperature distributions in the packed bed and periods of adsorption/desorption can be compositely explained by the shape of their isotherms, adsorption/desorption rates and bed density. However, large radial temperature distributions in the direction of the packed bed occur during both the adsorption and desorption processes. This suggests that enhancement of heat transfer in the packed bed is indispensable for this type of AHP.
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  • Tomohide Watanabe, Motohito Hayashi, Hitoki Matsuda, Masanobu Hasatani
    1993 Volume 19 Issue 1 Pages 91-98
    Published: January 10, 1993
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    To achieve high reactivity of CaO particles produced from calcined limestone, the influences of calcination temperature on reactivity of CaO for recarbonation (which is a reverse reaction of calcination) and sulfurization were experimentally studied by use of thermogravimetric analysis. The CaO particle structure was studied by measurement of pore size distribution and SEM photographs. Furthermore, enhancement of CaO reactivity and change of CaO particle structure were achieved by water or steam vapor hydration/dehydration treatment, and the effect of hydration/ dehydration treatment on reactivity was studied.
    It was found that the calcination temperature influenced the reactivity as well as the reaction capacity. By increasing the calcination temperature, both reactivity and capacity were decreased because of the growth of CaO crystal and also of pore plugging. The calcined limestone treated by hydration/dehydration was remarkably enhanced in terms of reactivity by increasing the specific surface area caused by the formation of small crystals and the change of crystal shape. It was therefore suggested that a highly reactive CaO could be produced by hydration/dehydration treatment even though the CaO calcined at high temperature was of low reactivity.
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  • Hiroshi Takahashi, Ken-ichi Kikuchi, Takuo Sugawara
    1993 Volume 19 Issue 1 Pages 99-105
    Published: January 10, 1993
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The ion -exchange equilibrium and transport rate of yttrium and lanthanum were examined for a cation -exchange membrane, SELEMION CMV. Yttrium and lanthanum were selectively sorbed by the membrane in a low -concentration region. Their selectivity coefficients were higher than those of divalent ions, depending on the degree of solution concentration. Experimental results were successfully correlated with separate experimental equations for Y -H and La -H systems over a wide range of solution concentration. In Donnan dialysis experiments with YCl3-HCl and LaCl3-HCl systems under the conditions of membrane diffusion control, the apparent diffusivities of yttrium and lanthanum were considerably affected by solution con-centration. Self -diffusivities of ions in the membrane were estimated from a part of the experimental results with a model using the Nernst -Planck equation by means of the Marquardt optimizing method. Those of H+, Y3+, and La3+ were 1.1×10-10, 1.1×10-12, and 4.4×10-13m2/s respectively. The model with the self-diffusivities explainedthe experimental results well.
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  • Yoshihiko Honda, Hiroshi Aoyama, Kiyotaka Okamoto, Seiji Kurosawa, Hir ...
    1993 Volume 19 Issue 1 Pages 106-113
    Published: January 10, 1993
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Effect of behavior of resin particles on liquid mixing in a horizontal rotary-column reactor, which was developed for hydrolysis of lactose in milk, was studied and the following results were obtained. 1) According to liquid flow rate, rotational speed (centrifugal force) and presence of air in the column, the behavior of resin in liquid was classified into three modes as follows : separation into two phases of pure liquid and particle bed ; formation of particle bed with particle-dispersed phase ; and fully developed dispersion without particle deposition. 2) The liquid mixing was mainly caused by slip velocity between particle and liquid, stream through particle bed and stirring by air. 3) It was found that the Peclet number for liquid mixing is closely related to the ratio of particle bed volume to whole column volume. 4) Critical conditions for a particle to deposit on form bed and for separation into pure liquid and solid phases could be estimated on the basis of the balance of forces acting on the particle.
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  • Yoshio Otani, Hitoshi Emi, Tetsuya Morizane, Jisaku Mori
    1993 Volume 19 Issue 1 Pages 114-119
    Published: January 10, 1993
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Removal of fine particles from wafer surface by air jets was experimentally investigated in order to seek a surface-cleaning method that does not use cleaning liquids. Monodisperse polystyrene latex particles with diameters between 0.25-3.3 μm were deposited on a silicon wafer by gravitational settling and were removed by air jets from a rectangular nozzle. Particles were blown off the moment the air jet struck the wafer surface, and afterwards almost no particle reentrainment occurred. This suggests that sequential pulses of air jet are effective for the removal of fine particles. By exposure of wafer surface to sequential pulse jets, particles with a diameter of 0.25 1μm were almost completely blown off the surface. The experimental results also indicated that the removal efficiency of particles per pulse jet, which is the ratio of number of particles reentratined during exposure to a pulse jet and that before the exposure, is kept constant for each exposure to sequential pulse jets.
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  • Kazuhiro Takeda, BohYoh Shibata, Yoshifumi Tsuge, Hisayoshi Matsuyama
    1993 Volume 19 Issue 1 Pages 120-123
    Published: January 10, 1993
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A method of evaluating the accuracy of fault diagnosis based on a weighted signed directed graph with delay is described. A tank-pipeline system is taken as an example to show the usefulness of this method and the influence of the value of allowance on the accuracy of fault diagnosis.
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  • Kenji Takahashi, Muneyoshi Kaji, Shigeru Mori, Akira Tanimoto
    1993 Volume 19 Issue 1 Pages 123-127
    Published: January 10, 1993
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Effects of vibration on longitudinal mixing of liquid were studied both in a multistage and a single-stage bubble column. Peclet numbers increased with increasing amplitude of fluid vibration at low gas velocities in the single -stage column. When the gas velocities were greater than 3.0 cm/s, however, there was little change in the Peclet number in the single-stage column. In the multistage column, Peclet numbers showed maximum value when the amplitude ratio was 0.04 and when the gas velocities were smaller than 3.0 cm/s. When the gas velocities are greater than 8.0 cm/s, vibrations have no effect on the Peclet number. The effects of fluid vibration on longitudinal mixing were discussed, based on the motion of a bubble in an accelerating fluid.
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  • Kenji Takahashi, Shigeru Kawabata, Shigeru Mori, Akira Tanimoto
    1993 Volume 19 Issue 1 Pages 127-130
    Published: January 10, 1993
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Mass transfer under the combined convection condition in a vibrating flow imposed on a steady fluid flow in a pipe was studied by using an electrochemical method. We found that the mass transfer for pulsating flow can be expressed by the following 3rd- and 4th-power relations in the present experimental range.
    kfv3=kf3+kv3
    130<Ud/ν<1600, 170<d2ω/ν<1600, 500<aωd/ν<1000
    kfv4=kf4+kv4
    330<Ud/ν<1600, 1600<d2ω/ν<2100, 1000<aωd/ν<3000
    where subscript f means steady fluid flow, v vibrating flow and fv pulsating flow.
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  • Keisuke Fukui, Satoshi Syoya, Tatsuo Kanki
    1993 Volume 19 Issue 1 Pages 131-134
    Published: January 10, 1993
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Processes of forming an organized turbulent thermal plume are investigated in unstable stratified and in combined stably and unstably stratified turbulent flows between parallel flat plates by conditional sampling measurement, in which temperature fluctuation near the wall is used as the detecting signal. The turbulent thermal plume is found to form in an unstable region of both combined and unstable stratified flows. The width of turbulent thermal plume increases downstream in developing unstablystratified turbulent flow. In combined stratified flow, however, development of the thermal plume is suppressed because the stably stratified flow existed over the unstable flow.
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  • Kohei Ogawa, Jun-Sug Lee
    1993 Volume 19 Issue 1 Pages 134-137
    Published: January 10, 1993
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Four types of regular arrangement and random arrangement of spheres are used as the objects of study. The local velocity gradient on the surface of the probe sphere is measured by using an electrochemical method. Three types of flow behavior -- mixing, plug and transient flow -- are characterized from the fluctuation intensity and the energy spectrum function. The relationship between flow characteristic and packing arrangement is made clear.
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  • Masami Furuuchi, Hiroshi Haseda, Keishi Gotoh
    1993 Volume 19 Issue 1 Pages 137-140
    Published: January 10, 1993
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Rod-like nonmagnetic particles dispersed in a magnetic fluid were packed by draining the fluid, after causing them to parallel to the applied magnetic field. The influences of the initial particle volume fractionφ0 and the field intensity H on the finalpacking densityφ and the particle orientation were experimentally examined.
    The increase inφ0 and H caused the particles to align more nearly parallel tothe applied field, giving rise to increase inφ. From electrical conductivity measurement it was estimated that, at maximum, 30% of the particles aligned parallel to the applied magnetic field and 70% remained in random arrangements.
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