KAGAKU KOGAKU RONBUNSHU
Online ISSN : 1349-9203
Print ISSN : 0386-216X
ISSN-L : 0386-216X
Volume 21 , Issue 4
Showing 1-34 articles out of 34 articles from the selected issue
  • Tatsuo Go, Munetaka Honda, Kunio Kato
    1995 Volume 21 Issue 4 Pages 641-647
    Published: July 10, 1995
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The production process for spherical particles by flame spraying is a method for exposing solid particles to the combustion flame and to fuse them to make spheres. This process is used for producing ceramic or metal spherical particles. In the development of this process it is very important to analyze the fusing and sphering phenomena of the solid particles quantitatively. A combustion model of the fuel gas flame from the double-pipe nozzle jet was formulated and the flame gas velocity and the axial temperature distribution were calculated by this model. These calculated results were approximately in accordance with the observed flame shapes. It is possible to calculate the heat transfer rate from the flame gas to the solid particles by this model.
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  • Tatsuo Go, Munetaka Honda, Kunio Kato
    1995 Volume 21 Issue 4 Pages 648-656
    Published: July 10, 1995
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The production process for spherical particles by flame spraying is a method for exposing solid particles to the combustion flame and to fuse them to make spheres. It is used for producing ceramic or metal spherical particles. In the development of this process it is very important to analyze the fusing and sphering phenomena of solid particles quantitatively. In this study a model of momentum and heat transfer in the process was formulated to analyze these phenomena. The velocity distribution of the particles, the temperature distributions in the particle, and the melting state were calculated by this model. Spherical particles of alumina and silica were produced in experiments using the flame spray method. These experimental results were approximately in accordance with the calculated ones. From these results, the model was found to be very useful for process analysis of the production of spherical particles from solid powder by the flame spray process.
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  • Mitsuhiro Ito
    1995 Volume 21 Issue 4 Pages 657-665
    Published: July 10, 1995
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    By employing operational data, the applicability of the following comminution kinetics equation to closed-circuit grinding for cement was investigated.
    R (Dp, t) /R (Dp, 0) =exp (-ktDnp)
    It is revealed that k and n vary with the progress of comminution, though these values are formerly regarded as constants. The value of n is affected by the grain size, and the value of k varies with n. And this relation is expressed by the following equation.
    k=5.93×10-4 (22.5×10-6)-n
    When the equation is substituted for the comminution kinetics equation, n is the only parameter for change of the size distribution by grinding. R (Dp, t) /R (Dp, 0) is a constant value at Dp=22.5×10-6m for the same grinding time : there is a fixed point Ps(Dp, R(Dp, t) /R(Dp, 0)) which satisfies for all k and n.
    Moreover, some compensation for k is needed, but it is less than 4 μm.
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  • Mitsuhiro Ito
    1995 Volume 21 Issue 4 Pages 666-673
    Published: July 10, 1995
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Using a comminution kinetics equation containing the parameters k and n, and a classification efficiency equation derived from the operational data of three kinds of representative classifiers, a simulation of closed-circuit grinding was carried out.
    The higher the efficiency of classification, the more the production rate increases. The production rate, however, decreases with excess increase in classification efficiency, when the fineness is expressed by the specific surface area. Also, the powder passing rate, which is indicative of the maximum production rate, through the mill shifts to a higher valve as classification efficiency increases. The parameters, k and n, , have a specific relation under the usual condition of cement grinding. In this condition, the production rate, which is controlled in a constant specific surface area, increases with decrease in the parameter n.
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  • Yoshio Yonei, Masao Kobari, Chiaki Yokoyama, Kunio Arai
    1995 Volume 21 Issue 4 Pages 674-682
    Published: July 10, 1995
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    To determine the optimum operating conditions for extraction of high quality flavor from tobacco leaves with high pressure CO2, we systematized experimentally the relation between the operating conditions and flavor quality by semi-batch extractions with liquid and/or supercritical CO2 solvent. Firstly, a general classification method of flavor components was proposed, in which the flavor components were grouped into three components based on chemical characteristics, that is a water-soluble flavor, an essential oil, and nonvolatile flavor components. Then, this method was applied to the tobacco flavor and three principal flavor compounds were selected from each component; nicotine from the water-soluble flavor component, neophytadiene from the essential oil component, and solanesol from the nonvolatile flavor component. We investigated the relation between the operating mode and condition and the composition of the principal components and/or flavor quality. It was found that the composition of the principal compounds can be varied widely by the operating conditions. Based on this result, an operating map was constructed which represents a relation between the operating condition and the composition of the principal compounds. Furthermore, the composition of the principal components of the high quality tobacco flavor determined by sensory evaluation tests was found exist in a specified area in the triangular diagram of the three principal components. This triangular diagram was a composition map which relates between the composition of the principal compounds and the quality of tobacco flavor. The optimum operating conditions for tobacco flavor having an objective quality can be determined systematically by matching the operating map and the composition map.
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  • Mitsunori Kishi, Satoru Inoue, Hironobu Imakawa, Morio Okazaki
    1995 Volume 21 Issue 4 Pages 683-689
    Published: July 10, 1995
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    In a multi-stage coating and drying process, in which PVA (Polyvinyl alcohol) film was formed by repeating twice a set of operations consisting of coating PVA aqueous solution and convective drying of it, the drying process was numerically simulated using a drying model based on mass transfer within a coated film. The possibility of minimizing drying time was also investigated.
    Total drying time, summed over the first and second stages, required to yield a target mean moisture concentration in the solution film was calculated while changing the final mean moisture concentraion of the first stage. It was found that the minimum drying time appeared for each target concentration and the effect of reduction on the total drying time became significant with increasing target concentration.
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  • Shigeyuki Mori, Sumio Nagata, Ryuichi Ueoka
    1995 Volume 21 Issue 4 Pages 690-695
    Published: July 10, 1995
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The technical art “Bekko” is one of the traditional technologies in Japan and the materials of “Bekko” are shells of hawksbills. In the course of tortoiseshell work, materials of good quality are used preferentially and the waste (so called unused materials) amounts to about 40 %. We have thus tried to utilize effectually the unused materials.
    The noteworthy aspects in this study are as follows : (a) It has been clearly established that the unused materials could be regenerated by molding after reducing to powder. (b) It is also possible to extract the valuable components with amber color from unused materials using organic solvent (DMSO).
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  • Noboru Kamei, Setsuro Hiraoka, Yoshihito Kato, Yutaka Tada, Hiroshi Is ...
    1995 Volume 21 Issue 4 Pages 696-702
    Published: July 10, 1995
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The previously proposed correlations of power consumption in baffled agitated vessels with paddle and turbine impellers showed some contradictions. The difference of impeller level among the given experimental conditions was believed to cause them. In the present work, the change of power number with the impeller level and the impeller dimensions was investigated experimentally. Then, it was confirmed that the contradictions among the power correlations depended strongly on the impeller level, and that the change of power number with the impeller level was closely related to the change of flow pattern in a vessel. A major factor which influenced this change was experimentally confirmed to be the ratio of impeller level to vessel diameter.
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  • Yoshitomo Hanakuma, Kazutoyo Nakaya, Kenji Takeuchi, Takashi Sasaki, E ...
    1995 Volume 21 Issue 4 Pages 703-706
    Published: July 10, 1995
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A method of detecting abnormal process signals in fault diagnosis using recursive maximum likelihood method and baysian statistical inference was developed. It involves the sequential probability ratio test using baysian statistical inference for residual sequence of model estimation error by recursive maximum likelihood method. The method proposed in this study has the advantage of detecting online abnormal signals in industrial use. It was applied to abnormal detection of the catalyst feed flow in a linear low-density polyethylene plant to confirm the design philosophy. The actual result indicates that the proposed method is effective in detecting abnormal process signals.
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  • Hiroshi Yamaguchi, Kei Yokoyama, Yuzo Sanada, Tadatoshi Chiba
    1995 Volume 21 Issue 4 Pages 707-714
    Published: July 10, 1995
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Slurry viscosity in the preheater of the NKK 2.4 ton/day direct coal liquefaction process was estimated from observed results of pressure-drop and temperature distributions through the preheater. The estimation of slurry viscosity was performed by utilizing the modified Lockhart-Martinelli (L-M) method for gas-liquid two-phase flow at normal temperature and pressure. In this method, the relationship between the fluid parameter, X, and the square root of the pressurd drop ratio, φg, for the gas phase was modified for estimated results to fit those observed for a cold hydrogen-gas/creosote oil system and for a hot hydrogen-gas/anthracene oil system. On the basis of the modified relationship, the slurry viscosities were estimated for hydrogen rich gas/Illinois No. 6 coal particles-anthracene oil slurry system under liquefaction conditions. The estimated slurry viscosity was found to increase with the initial volume concentration of coal particles in the slurry. The viscosity also increased monotonouly with temperature for slurries having lower coal concentrations, while exhibiting a maximum for those with higher coal concentrations, implying that the viscosity change was caused by swelling of coal particles. The difference of temperature ranges for viscosity peak appearance in the preheater and in a batch viscometer was recognized and attributed to differences in the slurry heating rates between the two apparatus.
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  • Tadaatsu Ido, Ken Yamaguchi, Hajime Itoh, Shigeo Goto
    1995 Volume 21 Issue 4 Pages 715-722
    Published: July 10, 1995
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    In a phase transfer catalytic system, a third phase (referred to as a middle phase) was developed with dodecane (organic phase), sodium sulfide saturated water (aqueous phase), and ammonium salts or phosphonium salts with molecular weights of 322-507.
    Catalytic activity of the middle phase was tested by the reaction of benzyl chloride (in a organic phase) and sodium sulfide (in a aqueous phase). The catalytic activity was strongly dependent on experimental conditions such as the molecular weight of catalyst, concentration of sodium sulfide and the ratio of organic phase to aqueous phase.
    Four kinds of catalysts with different molecular weights were tested in this study. In the case of hexadecyl tri-n-butylphosphonium bromide catalyst (with the highest molecular weight), the rate of reaction was dependent on the concentration of sodium sulfide and a maximum rate was observed. In the case of tetra-n-butylammonium bromide catalyst (with the lowest m.w.), the activity appeared only when the concentrations of sodium sulfide was near saturation. In the case of tetrahexylammonium bromide catalyst (with medium m.w.), the rate of reaction in creased with concentration of sodium sulfide, and the activity was the highest. The differences in activity for the different molecular weights could be explained by the difference of hydrophilicity and lipophilicity of the middle phase. When toluene was used as an organic phase, the middle phase was not developed and the catalyst could be used as an ordinary phase transfer catalyst. The same reaction was compared for these four catalysts with toluene as an organic phase. The catalytic activities of these catalysts were higher when the middle phase was developed.
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  • Kuniaki Gotoh, Minoru Tagaya, Hiroaki Masuda
    1995 Volume 21 Issue 4 Pages 723-731
    Published: July 10, 1995
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The mechanism of particle removal was studied using a high speed air jet. The experiment was conducted for latex particles of 110 μm diameter adhering to a plane surface of glass under various jet pressures and impinging angles. It was found that the removal force decreased with decreasing the impinging angle below 45°. For an impinging angle above 45°, the removal force did not depend on the angle. From the experimental data, the relation between removal force which remove 50% of deposited particles and particle diameter was elucidated.
    The relation between removal force and particle diameter could not be explained by the conventional model, in which the removal force was assumed to be equal to the bending moment calculated by use of the time-averaged velocity profile. Experiments conducted under various jet duration times revealed that the change of removal efficiency with time was related to the removal force. Thus, it was concluded that the flow controlling the removal force was not only caused by the average flow but also by the fluctuation of the flow.
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  • Mikio Kumita, Fujio Watanabe, Masanobu Hasatani
    1995 Volume 21 Issue 4 Pages 732-739
    Published: July 10, 1995
    Released: November 12, 2009
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    Numerical analysis of CO2 separation from CO2/N2 mixtures by a pressure swing adsorption (PSA) method using a granular molecular sieving carbon (MSC) was carried out employing a mathematical model to evaluate the performance of the CO2-PSA separation. The possibility of obtaining the highly concentrated CO2 by the PSA method was discussed on the basis of both experimental and calculated results.
    Since the calculated results agreed roughly with the experimental results on the CO2-PSA separation, the validity of the numerical analysis was proved. The performance of the CO2-PSA separation could be estimated by using the Langmuir multi-component isotherm and diffusivity for each component of the MSC. By this numerical analysis, the concentration profiles of CO2 and N2 in both gas and solid phases in the adsorbent bed were predicted. Furthermore, it was found that the highly concentrated CO2 can be obtained by conducting multistage PSA operations and/or purge operations in the PSA cycle.
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  • Shinji Shimosaki, Makoto Kuramoto
    1995 Volume 21 Issue 4 Pages 740-745
    Published: July 10, 1995
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The reaction rate of the reduction of TiCl4 with Mg was studied by means of an impulse response method. In the case of gaseous TiCl4 feed, the reaction rate was proportional to the concentration of TiCl4 and the apparent activation energy was obtained as 59 kJ · mol-1 In the case where liquid TiCl4 was fed onto the molten Mg, TiCl4 was vaporized and then reacted with Mg. The reaction was found to be controlled by the vaporization process of TiCl4. Therefore, the production rate of Ti can be increased by improvement of the vaporization process.
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  • Yuji Kiguchi, Takayuki Watanabe, Atsushi Kanzawa
    1995 Volume 21 Issue 4 Pages 746-752
    Published: July 10, 1995
    Released: November 12, 2009
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    The reaction system of tert-butanol/isobutene/water was considered for use in chemical heat transport. In this study, the heat transfer characteristics in an endothermic tert-butanol dehydration reaction which occurred in the heat supply side of this reaction system was investigated. The heat flow was obtained by measuring the reactant composition change and temperature change in the catalyst bed. The heat flow consists of reaction heat, the latent heat of isobutene, and sensible heat in this reaction system. Numerical calculations based on a two-dimensional model were carried out and the results showed good agreement with experimental ones. It was noticed that the heat flow with chemical reaction was much higher than without reaction. These results indicated that the dehydration reaction promoted the heat transfer rate, because of the increase in temperature difference between the heating medium and the wall by making use of chemical reaction for heat transport. The apparent local heat transfer coefficient with chemical reaction was higher than without reaction. The possibility of a high efficiency heat transport which used this reaction system was suggested.
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  • Kazuhiko Kato, Koichi Yamada, Atsushi Inaba, Kosuke Kurokawa, Hiroshi ...
    1995 Volume 21 Issue 4 Pages 753-759
    Published: July 10, 1995
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    For photovoltaic (PV) energy systems, we estimated CO2 emissions per kWh under technology development and expansion of the cell production scale, considering the life cycle of the PV energy system, including as module production ana power plant construction. For polycrystalline silicon cells, CO2 emissions of a 3 kW PV system and a 1000 kW PV system were 17g-C/kWh and 39g-C/kWh, respectively, when the annual cell production scale was 10 MW. On the other hand for amorphous silicon cells, they were 10g-C/kWh and 47 g-C/kWh, respectively. In order to reduce CO2 emissions of PV energy systems, it is necessary to use less raw materials which are needed in proportion to the area of the module, such as alminum frame and cover grass. Improvement in total system efficiency, including the cell efficiency and the lifetime, is also effective in reducing CO2 emissions of PV energy system.
    We also evaluated the relation of CO2 emissions of electric power output between PV energy system and utility to be used for module production for the case of a PV system being widely introduced into the utility grid, because the CO2 emissions of PV power output depend on utility power output.
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  • Mitsuo Kamiwano, Meguru Kaminoyama, Kazumi Yamamoto
    1995 Volume 21 Issue 4 Pages 760-765
    Published: July 10, 1995
    Released: November 12, 2009
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    This study proposed a real-time and multi-point temperature measuring system. This system is capable of measuring temperatures simultaneously from many sensors set in or on an object. Namely, the basic principle of this system is as follows : first, the data measured from the thermocouples are amplified as analog-signals and taken into the sample & hold circuit simultaneously at intervals of a setting time step. Next, while a set of this data has been held in the sample & hold circuits, it is switched in turn over to an A-D converter by an analog multiplexer, then each set of data is transformed to digital by the A-D converter. After that, they are displayed with a personal computer simultaneously. This instrument can grasp in detail a heat transfer phenomenon which is changing unsteadily with time.
    As a practical application, for the purpose of comparing this system with a scanning system, which has been generally used before, a thermal mixing process was measured with both systems, and this system was found to be more useful than the scanning system. For further practical use, the following measurement was also carried out : the measurement of changing temperature distribution in solution polymerization.
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  • Koichi Fuchino, Yasushi Kawabata, Shigeyuki Tateno, Yoshihumi Tsuge, H ...
    1995 Volume 21 Issue 4 Pages 766-775
    Published: July 10, 1995
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    An efficient algorithm is presented for diagnosing faulty sensors by use of x2testing and linear relationships among measurable variables in steady states of continuous processes. A method is also developed for the design of a diagnosis systems utilizing this algorithm. The efficiency of the presented algorithm and the accuracy of the suggested design method are demonstrated by numerical experiments. This method is useful to diagnose baised flow meters by integrated flowrates.
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  • Sang-Joon Cho, Yoshio Otani, Hitoshi Emi
    1995 Volume 21 Issue 4 Pages 776-784
    Published: July 10, 1995
    Released: November 12, 2009
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    Separator-type HEPA filters are composed of elements which have square cross section bounded by two separator walls and partitioned by a filter medium. Therefore, it is possible to characterize pressure drop of a separator type air filter unit by studying the pressure drop of these filter elements.
    In the present work, the similarity law for the flow channels including a porous media was discussed and the dimensionless parameters which determine the pressure drop were derived. The dimensionless pressure drop was presented as a generalized-pressure drop diagram in terms of dimensionless parameters. Furthermore, the results of numerical analysis for the two-dimensional model filter were compared with those of experiments with two-and three-dimensional model filters. The prediction equation for optimum separator height, which is the most important factor for designing the filter unit, was presented as a function of filter media resistance and filter depth.
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  • Takahiro Horiuchi, Yasuo Kousaka, Yoshiyuki Endo
    1995 Volume 21 Issue 4 Pages 785-792
    Published: July 10, 1995
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The mechanism of dispersion of coagulated particles consisting of two equalsized spheres (doublet) in a shear field in water is discussed.
    1) A definition of dispersibility is proposed as DM=Mb/Mt. Here, Mb is the bending moment induced by the drag force on the doublet in a simple shear field, and Mt is the moment required to separate the two adhering spheres. DM is thus a measure of the easiness of particle dispersion. A theoretical model is presented which relates DM to the primary particle diameter, shear rate and adhesion force between particles.
    2) Coagulated particles consisting of monodisperse standard PSL (polystyrene latex) spheres (1.1, 1.9 and 5.2μm in diameter) were dispersed in a concentric rotating cylinder. During the process, there are two phenomena competing against each other : dispersion and shear coagulation. The relative contribution of these mechanisms is controlled by the value of DM Thus, for DM>1, it is found that doublets become dispersed; in contrast, when DM<1, shear coagulation overcomes dispersion and, as a result, new doublets are formed in addition to those originally existing.
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  • Akihiro Kataoka, Takashi Ihara, Hitoki Matsuda, Masanobu Hasatani, Woj ...
    1995 Volume 21 Issue 4 Pages 793-799
    Published: July 10, 1995
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A circulating fluidized bed equipped with a nozzle burner in the bottom part of the riser for low calorific gas combustion was proposed. In this study, the effect of sensible heat of solid particles on the combustion characteristics, NOx emission characteristics and the possibility of NOx control were studied by using simulated coal gasification gas.
    The following conclusions were drawn.
    · Combustion characteristics for low calorific gas were improved by the effect of thesensible heat of particles.
    · The conversion ratio from NH3 in the fuel to NOx decreases with increasing heatvalue of fuel, and increasing NH3 concentration in the fuel.
    · NOx emission was controlled by the effects of staged combustion and heatrecirculation by particles.
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  • Kazunari Ohgaki, Takahiro Hamanaka
    1995 Volume 21 Issue 4 Pages 800-803
    Published: July 10, 1995
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    High-pressure phase-behavior of CO2 hydrate-liquid CO2-H2O mixture was investigated in the temperature range from 283.3 to 288.5 K and over a pressure range of 8 to 82 MPa. The observed phase boundary corresponds to the three-phase coexisting line with a nonvariant point of CO2 hydrate-liquid CO2-gaseous CO2-H2O quadruple point. Phase density-inversion between CO2 hydrate, liquid CO2 and H2O phases was also observed.
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  • Tadaatsu Ido, Ken Yamaguchi, Takanobu Yamamoto, Shigeo Goto
    1995 Volume 21 Issue 4 Pages 804-808
    Published: July 10, 1995
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Repeated use of a phase transfer catalyst was studied. The catalyst (hexadecyl tri-n-butyl phosphonium bromide) was concentrated in a third phase (referred to as a middle phase) which was developed between the organic phase and the aqueous phase. The middle phase was observed only when dodecane was used as an organic phase and the aqueous phase was saturated with pottasium bromide. The middle phase could catalyze the substitution reaction of benzyl chloride with Br-, the former was located in the organic phase and the latter in the aqueous phase. After the reaction was completed, the reaction mixture (organic phase) was removed and a new organic phase was charged. By this operation, the middle phase could be used repeatedly.
    A new operation method was investigated in order to avoid direct contact between the organic phase and the aqueous phase. The three phases were settled without stirring and the transfer of the reactants was promoted by ultrasonic waves through the interface of the phases. The middle phase catalyzed the reaction by this ultrasonic operation.
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  • Yoshiaki Sawada, Yoshiteru Kageyama, Masashi Iwata, Shigehisa Harada, ...
    1995 Volume 21 Issue 4 Pages 808-811
    Published: July 10, 1995
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Primary diameter, length and shape of secondary particles of ultrafine iron particles prepared by pyrolysis of Fe (CO) 5 were controllable by the reaction temperature and concentraion of Fe (CO) 5, and were not affected by reactor size. The reaction temperature and concentration of Fe (CO) 5 in a 2-inch reactor should be reduced to prepare the same particles as obtained in a 1-inch reactor; the production rate in the 2-inch reactor was twice as long as that in the 1-inch reactor. The fractal dimension of typical secondary particles with maximum coercive force was 1.5-1.7, which was close to commercial ones.
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  • Naoki Katayama, Susumu Nii, Katsuroku Takahashi, Masamichi Kamihira, H ...
    1995 Volume 21 Issue 4 Pages 811-815
    Published: July 10, 1995
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    For electrodialysis of lactic and acetic acids, the effect of pH on the permeation behavior was examined. A strong basic or perfluoro anion exchange membrane was used. Even when the organic acids were undissociated, permeation of these acids was observed and the addition of HCl promoted the permeation rate. The permselectivity of lactic acid over acetic acid was large at low pH and decreased as the dissociation of acetic acid proceeded at high pH.
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  • Weiqing Ye, Shinichi Hara, Yuichi Ohira, Eiji Obata, Koji Ando
    1995 Volume 21 Issue 4 Pages 815-817
    Published: July 10, 1995
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Experiments dealing with the effects of TOA concentrations on time courses of chromium molar fractions in the external, organic and internal phases during the separation-concentration process of chromium were carried out using Span 80 and two kinds of polyamine surfactants, Polyamine-E and Polyamine-L. The optimum TOA concentration and the optimum extraction time were determined in order to obtain the maximum chromium molar fraction in the internal phase.
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  • Haruo Yamazaki, Kosuke Takahashi, Masashi Iwata
    1995 Volume 21 Issue 4 Pages 818-820
    Published: July 10, 1995
    Released: November 12, 2009
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    To analyze the frictional resistance of a rotating disk in a dynamic filter chamber without permeation, torque on the disk was measured in the laminar flow region of a Newtonian fluid using an aqueous solution of glycerin. For the region of the merged boundary layers of laminar flow, torque coefficients on both ungrooved and grooved disks depend upon the disk Reynolds number and chamber dimensions. For the region of the separate boundary layers of laminar flow, the dimensions of the groove also affect the torque coefficient. New empirical equations for the torque coefficient successfully correlate our data.
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  • Tohru Niida, Shinichi Ohtsuka
    1995 Volume 21 Issue 4 Pages 821-823
    Published: July 10, 1995
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The dynamic shape factors of two types of polyhedral shaped agglomerates were measured. One type consists of the close packing of 4 to 12 spheres.on a core sphere (close packed agglomerate, dynamic shape factor ks); the other has the same configuration as the above agglomerate except that the central sphere has been removed (hollow agglomerate, kv). The dynamic shape factor kvwas analyzed by using a model agglomerate in which the core void is simulated as a sphere of fluid (kf). Comparison of kv and kf shows that, for hollow agglomerates comprising a number of spheres between 5 and 13, part of the fluid flows through the core void.
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  • Toshitaka Funazukuri, Masahiro Nishio
    1995 Volume 21 Issue 4 Pages 824-828
    Published: July 10, 1995
    Released: November 12, 2009
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    An empirical correlation given by
    D12/T=1.013×10-14η-0.9222
    is proposed for predicting binary/pseudo binary diffusion coefficients of carbon dioxide in water and in aqueous electrolytic solutions, where D12 is diffusion coefficient [m2/s], T is temperature [K], and ηis viscosity [Pa s].The average absolute deviation AAD for this correlation is 5.6% for the literature data on D12 of CO2 in water with number of data points N of 79 and 3.9% (N=103) for those in aqueous electrolytic solutions. The above correlation obtained in this study is more accurate than the various empirical correlations proposed in the literature.
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  • Yasuo Kousaka, Yoshiyuki Endo, Takahiro Horiuchi, Isao Yamakawa
    1995 Volume 21 Issue 4 Pages 828-832
    Published: July 10, 1995
    Released: November 12, 2009
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    A simple method to disperse aggregate particles suspended in liquid is proposed. The method consists of successive freezing and melting of suspensions. Aggregates consisting of submicron particles were found to be almost completely dispersed into primary particles after about 5 freezing-and-melting cycles, provided that the particle surface could be well wetted with the freezing liquid (dispersion medium). As the dispersion mechanism, it is thought that when the liquid phase is frozen, the expansion or shrinkage of the volume of liquid existing between primary particles causes relative displacement between the particles. This displacement increases the interstice between them resulting in the decrease in adhesion force.
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  • Ken-ichi Kikuchi, Hiroshi Takahashi, Tatsuo Saito, Kazuhiko Ishida
    1995 Volume 21 Issue 4 Pages 832-835
    Published: July 10, 1995
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Laser fiber probes made it possible to measure the velocities and sizes of bubbles and slugs in three-phase upflow including glass beads, polystyrene beads, or CaCO3 of up to 30% through a 3.0 cm vertical tube. The bubble and slug velocities almost agreed with those for the gas-liquid two-phase flow under the conditions studied. The bubble diameters and gas slug lengths were often affected by solids of even lower concentrations. The flow pattern maps for the three-phase flow, including glass or polystyrene beads, showed broader bubble-flow regime at low gas velocities than that for the gas-liquid two-phase flow and the three-phase flow including CaCO3.
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  • Ryozo Watanabe, Motokazu Kikuchi, Shigemitsu Ishikawa, Junichi Otsuji, ...
    1995 Volume 21 Issue 4 Pages 835-838
    Published: July 10, 1995
    Released: November 12, 2009
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    Microwave heating has lately attracted attention in the field of food engineering, because it is suitable for pasteurization and sterilization of highly viscous foods or foods containing particulates. In the pasteurizing process, it is important to monitor precisely the temperature-time profile of food products. Under microwave heating, however, it is difficult to measure the correct temperature by conventional thermometer because of heat generation due to the microwaves. This paper is concerned with temperature measurement by a data-storage type thermometer under microwave heating. A technique is developed to eliminate the influence of heat generation due to the microwaves.
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  • Akihiro Kataoka, Manabu Okinaka, Hitoki Matsuda, Masanobu Hasatani, Wo ...
    1995 Volume 21 Issue 4 Pages 839-843
    Published: July 10, 1995
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Measurement of fluctuations in combustor and sound pressure are proposed as a new combustion detection method which can be applied for not only CFB combustion but also industrial furnaces. The proposed methods are supposed to be utilized for both remote controlled and untouched combustion detection systems.
    The following results were obtained. Pressure fluctuations in the combustor and frequency analysis of them were found to be successful and useful in detecting the combustion stability on CFB combustion. In addition to the above methods, sound pressure is also found to be useful in detecting the combustion stability on gas combustion.
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  • Masakatsu Miura, Shigenobu Tanaka, Koji Ando
    1995 Volume 21 Issue 4 Pages 843-846
    Published: July 10, 1995
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The yield of levoglucosan (LG : a kind of anhydrosugar) from wood particles by pyrolysis was studied using an infrared-ray furnace under various heating rates.
    A slight reduction of pressure was found to increase the yield of levoglucosan. The increase of heating rate resulted in an increase in the yield of levoglucosan and a decrease in the yield of solid product, as was the case for the reduction of pressure. However, at an extremely high heating rate, the yield of levoglucosan decreased. As a result of pyrolysis of Karamatsu under 88 kPa, the maximum yield of levoglucosan was obtained at a heating rate of nearly 1.3 K/s.
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