KAGAKU KOGAKU RONBUNSHU
Online ISSN : 1349-9203
Print ISSN : 0386-216X
ISSN-L : 0386-216X
Volume 18 , Issue 4
Showing 1-25 articles out of 25 articles from the selected issue
  • Masafumi Matsumoto, Toshikiyo Hashimoto, Katsuhide Murata, Shigeo Goto
    1992 Volume 18 Issue 4 Pages 389-394
    Published: July 10, 1992
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Carbon whiskers were produced in the gas phase by thermal decomposition of benzene in the presence of a catalyst. The effects of operation conditions such as the concentration of sulfur compound and feed temperature on product yield and the form of whiskers were investigated. Morphology and crystallinity of carbon whiskers and analysis of catalytic particles were characterized by SEM, TEM and X-ray diffraction.
    Sulfur was effective over a range of S/Fe (atomic ratio of sulfur to iron) from 0.17 to 0.52 on the formation of carbon whiskers.
    Thiophene was more effective than hydrogen sulfide on the yield of whiskers.
    The growth of whiskers was promoted over 720°C.
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  • Yoshinori Itaya, Masakatsu Mizuno, Tomoyasu Ito, Masanobu Hasatani
    1992 Volume 18 Issue 4 Pages 395-402
    Published: July 10, 1992
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A solar air heater packed with a salt hydrate was developed to improve the performance of both heat trap and storage. Using calcium chloride hexahydrate as the salt hydrate, a glass tube bundle packed with the salt was set in the collector. The air heater was exposed to radiant heating by infrared lamps. The heat trap and the storage characteristics of the air heater were examined by measuring the transient temperature distribution of salt and air in the collector.
    When the lamps were turned off after attainment of a steady-state heating condition, outlet air of stable temperature around at the melting point was obtained for a time longer than 5 hours, and a much greater effect of latent heat storage was observed in comparison with that of an air heater with glass tube bundle but without the salt. A suspension of fine graphite particles in the salt enhances the heat trap efficiency due to the change in its optical properties. The suspension not only increases the molten part of the salt close to the collector inlet but also improves the crystallization due to its function as a nucleus. The heat storage capacity increased as a result.
    Good performance of this type of solar air heater was also found in an outdoor experiment.
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  • Zhe-Shi Zhao, Hitoki Matsuda, Norio Arai, Masanobu Hasatani
    1992 Volume 18 Issue 4 Pages 403-412
    Published: July 10, 1992
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The gas-phase formation of NO, N2O and N2 through NH3 in a mixture of NH3, CO, O2 and Ar was studied. The results obtained by experiments with a tubular-flow reactor were compared with those obtained by theoretical analysis. In the theoretical analysis the reactant concentrations were calculated on the basis of 65 elementary reactions involving 21 chemical species. The results were compared with those obtained in a NH3/H2/O2/Ar gas system.
    The comparison between the experimental and calculated results was made in the temperature range of 950 K to 1350 K and with a composition of reactant gases at the inlet of NH3=1000 ppm, H2= 3.0 %, CO=3.0 %, and O2=0.0-3.0 %.
    It was found within the range of the present experimental conditions that : 1) the experimental trends were well explained by the calculated results with the reaction model employed and the mechanism of NH3 oxidation in the gas system of coexisting CO was confirmed : 2) the formation N2O was inhibited in the higher concentration range of H, O, OH, while the formation of NO was enhanced in the same concentration rang : and 3) the concentrations of NO and N2O produced were different in the NH3/CO/O2/Ar system from that in the NH3/H2 /O2/Ar gas system. This difference in concentration is due to the difference of contribution of H and OH radicals to the reaction.
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  • Yoshiyuki Bando, Makoto Nishimura, Hiroyuki Sota, Yoshinori Watanabe, ...
    1992 Volume 18 Issue 4 Pages 413-419
    Published: July 10, 1992
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    To develop a sparger with high energy efficiency for an aeration tank, a simultaneous gas-liquid injection sparger was developed. It consists of a nozzle with an orifice plate and a tube having a diameter slightly larger than that of the nozzle. Under various combinations of sparger dimensions the flow pattern was observed, and the entrained gas flow rate and volumetric mass transfer coefficient were measured.
    By placing the tube at the end of the nozzle, the liquid in the aeration tank was sucked into the tube and the entrained gas flow rate increased. The flow rate of sucked liquid was several times that of liquid feed. The nozzle length, orifice diameter, distance between ends of nozzle and tube, and diameter and length of tube had the optimum values for the entrained gas flow rate. In the experiment where the gas flow rate was constant, it was found that the orifice contributed greatly to bubble subdivision as well as to gas entrainment. In a comparison experiment, the entrained gas flow rate and volumetric coefficient in the case of the present sparger were higher than those in the case of a conventional sparger.
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  • Takahiko Kakoi, Kazuo Kondo, Masahiro Goto, Fumiyuki Nakashio
    1992 Volume 18 Issue 4 Pages 420-425
    Published: July 10, 1992
    Released: November 12, 2009
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    The stripping of palladium by thiourea, which was extracted with didodecylmonothiophosphoric acid, was carried out using a stirred transfer cell. The dependency of the stripping rate on the concentration of the chemical species was examined and the stripping mechanism was investigated. Measurements of interfacial adsorption equilibrium of the extractant and the palladium complex were also conducted.
    It was found that the extractant and the palladium complex had an interfacial activity. A model of interfacial reaction accompanying the reaction in an organic phase was proposed, and the experimental results were quantitatively explained by the model.
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  • Hideomi Abe, Takao Orimo, Keiichi Kotani
    1992 Volume 18 Issue 4 Pages 426-432
    Published: July 10, 1992
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The absorption rate of gas through monolayers has been investigated for four compounds (cetyl alcohol, stearyl alcohol, stearyl amine and stearic acid) and four gases (acetonitorile, methanol, acetone and methyl acetate) at room temperature under low vapor pressures. Monolayers were spread on the water substrate at their equilibrium spreading pressures.
    The rate-determining step for this system was the process of passing through the monolayers.
    The calculated permeability coefficients from the rate were analyzed on the basis of the Arrhenius equation.
    It was found that there is a compensation effect between the apparent activation energy and the pre-exponential factor of its rate constants for all monolayers. Namely, the rate constant has the same value for all permeants at a certain temperature. But this temperature is dependent on a polar functional group of monolayer compounds.
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  • Kunihisa Osasa, Hideo Nakakura, Masao Sambuichi
    1992 Volume 18 Issue 4 Pages 433-440
    Published: July 10, 1992
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Batch tests on emulsified oil-water dispersions were conducted by electroflotation using stainless steel mesh electrodes. The separation process occurred in two stages. In the first, oil concentration remained at the initial concentration. The retention time in column was inversely proportional to the initial average size of oil droplets. The zeta potential of oil droplets was decreased from the initial potential (about-60mV) to the critical coagulation potential (about-25 mV), and then oil droplets became unstable and either flocculated or coalesced. The second stage formed the flotation process, and the removal followed first-order kinetics. The rate constant of flotation was about 1.5 kC-1 regardless of the initial size of the oil droplets. Subsequent experiments were conducted to examine the effects of the addition of indifferent electrolytes and surface-active agents on flotation kinetics.
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  • Masatoshi Yoshida, Kohnosuke Matsui, Shigeru Matsumoto
    1992 Volume 18 Issue 4 Pages 441-447
    Published: July 10, 1992
    Released: November 12, 2009
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    A search method of optimal allocation of sensors is proposed for state estimation of a linear distributed parameter system. It was applied to a one-dimensional heat conduction process in order to test the state estimation performance. The results show that this method gives an accurate optimal allocation of sensors. It was also found that optimal-sensor location depends not only on the system dynamics but also on both the initial and steady states of the state variable. It was also suggested that increase in number of sensors would not always lead to improvement of estimator performance.
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  • Yasuyuki Watanabe
    1992 Volume 18 Issue 4 Pages 448-454
    Published: July 10, 1992
    Released: November 12, 2009
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    Characteristics of nucleation of NaCH3COO-3H2O melt with Na2SeO3 added as a nucleation agent were studied by a method of continuous cooling at a constant rate of 1 K/min after superheating for two hours at temperatures from 12 to 40 K higher than the melting point (331K). Na2Se03 crystals precipitated in the melt became active through experience of melt solidification, and then the supercooling temperature of the melt was decreased from higher than 42K to lower than 5K. It was observed in situ by an optical microscope that NaCH3COO·3H2O crystals were generated in the vicinity of the Na2SeO3 crystals and almost simultaneously at various points. The Na2SeO3 crystals kept their activity at a temperature up to 28K for superheating, but began to lose it by heating over that temperature and became completely inactive above a superheating temperature of 36K. After the inactivation, the melt was supercooled more than 79K and reverted almost to the same characteristics of nucleation as before activation.
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  • Kanji Matsumoto, Shigeru Hirata, Haruhiko Ohya
    1992 Volume 18 Issue 4 Pages 455-462
    Published: July 10, 1992
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    It is often observed that microfiltration processes depend on particle concentrations in suspensions. There is, however, no filtration model which is applicable to the wider range of particle concentrations, especially an intermediate one. We propose a new filtration model applicable to the entire range of dilute to dense suspensions when the particle size in the suspension is larger than the membrane pore size. This new model consists of two models. One is called the incomplete pore-blocking model, which is a combination of a complete blocking model and a cake-filtration model, and has the capability of estimating the pore-blocking efficiency from experimental data as a function of particle concentration. The other is a particle capture model which introduces the particle collection efficiency of a unit particle layer in a cake.
    From an investigation of experimental data from constant-pressure batch filtrations of monodispersed latex-particle suspensions, the following observations were made ; (1) incompleteness of pore blocking by the particles became larger at higher particle concentrations, and (2) the probability of particles passing through a unit particle layer in the cake was about 5% and did not depend on the particle concentration.
    This new model allowed us to estimate the final blocking ratio of the membrane pores for the first time.
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  • Hikari Murakami, Ryoichi Haga, Nobuko Nishimura, Harumi Matsuzaki, Sei ...
    1992 Volume 18 Issue 4 Pages 463-470
    Published: July 10, 1992
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Effects of protective polymeric additives on cell damage caused by sparging in a serum-free suspension culture were studied using 100 cm3 spinner flasks and a 1l perfusion culture apparatus with cell filtration membrane.
    Cell damage caused by sparging was reduced by various additives. These effects can be attributed to a decrease in surface tension of serum-free media by the additives to the same extent as the serum-added medium (about 50 mN/m) reduced hydrodynamic stress by sparging. Moreover, the appearance of small particles and dead-cell aggregation were repressed and the lifetime of the cell filtration membrane was prolonged.
    Consequently, a long-term (longer than one month) perfusion culture with serumfree medium was achieved.
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  • Kunio Horiuchi, Toshinori Kojima, Atsushi Inaba
    1992 Volume 18 Issue 4 Pages 471-477
    Published: July 10, 1992
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Most ocean models so far proposed have taken only the inorganic carbon cycle into account. In our previous study, a model in which the carbon fixation by plant biota and the sedimentation of carbonaceous particles were considered was proposee. In the present study, an unsteady-state model is developed by improvement of the previous model incorporating gas exchange between the ocean surface and the atmosphere. The results are compared for the airborne fraction of CO2 from fossil fuel between the conventional two-box model and our model. Despite the expectations in the previous study, it was found that the amount of CO2 absorbed from the atmosphere into the ocean does not increase, as far as atmosphere-surface and surfacedeep sea exchange coefficients are determined from 14C distribution data. However, this model is physically sound as compared with conventional one. Furthermore, this model not only predicts airborne fraction variation but also estimates the validity of various techniques for solving CO2 problem.
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  • Kazuyuki Suzuki, Yasunori Tohya, Masaaki Kakumoto
    1992 Volume 18 Issue 4 Pages 478-486
    Published: July 10, 1992
    Released: November 12, 2009
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    To analyze the performance of a sewage treatment plant with the activated sludge process, a mathematical model must be developed. But we have no good model because of the complexity of an actual process, including large disturbances of inputs and lack of accurate instruments for measuring state variables.
    In this paper a fuzzy modeling method based on fuzzy sets theory, including both statistical analysis and representation by using fuzzy rules, is applied to modeling and analyzing the static performance of activated sludge sewage treatment processes.
    In the fuzzy modeling, process characteristics are represented by IF-THEN rules. Fuzzy variables in the premise (IF) part and a multiple-regression linear model in the consequent (THEN) part constitute a rule. Each rule claims local characteristics in each sub-space. Integrating these sub-models by fuzzy inference, we can predict the process performance more correctly.
    The static performance of many sewage treatment plants in Japan have been evaluated by fuzzy modeling. The results show that the fuzzy model is superior to a conventional multiple-regression linear model in describing process performance. Fuzzy modeling is also expected to be an effective method for other ill-structured processes.
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  • Haruo Yamazaki, Toshiro Murase, Masashi Iwata, Mompei Shirato
    1992 Volume 18 Issue 4 Pages 487-494
    Published: July 10, 1992
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    In a dynamic filter with a rotating disk, the rotor should be such that the induced slurry flow completely sweeps a cake from a filter medium. To analyze the effects of shearing action on filtration flux, measurements of the tangential velocity distribution were carried out for a rotating grooved disk enclosed within a filter chamber without permeation using an non-Newtonian power law fluid (aqueous solution of sodium polyacrylate). The frictional resistance of the rotors was also studied experimentally.
    The tangential velocity profile of the grooved rotor in the axial direction can be divided into three regions : boundary layers on the rotor and the fixed plate and fluid core between them. The flow consists of a laminar or turbulent flow with two separate boundary layers. With increasing number of grooves or their width, the tangential velocity increased fairly as compared with that for an ungrooved disk. The velocity profile could be evaluated in terms of the ratio K of the tangential velocities of the core and the rotating disk. The K-value was empirically determined from calculations based on newly defined operational factors, thus providing a method for estimating the velocity of the liquid in the filter. The torque coefficient Cm of grooved disks could also be correlated with the same factors for the K-value, using the torque coefficient Cm0 of an ungrooved disk.
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  • Kohei Ogawa, Shiro Yoshikawa, Hirohisa Shiode
    1992 Volume 18 Issue 4 Pages 495-501
    Published: July 10, 1992
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The effects of liquid kinematic viscosity and operational conditions on the discharge flow field, which is the most important area in a stirred vessel with aeration, are investigated experimentally. The test liquids are 0.5 wt% polyacrylamide aqueous solution, 40 wt% and 60 wt% glycerol aqueous solution and water. The test gas is air.
    The local liquid velocity in the discharge flow field in a stirred vessel with four baffles and a ring sparger is measured by an electrodereaction velocimeter consisting of four small spherical platinum electrodes. The effects of the liquid kinematic viscosity, the impeller rotational speed and the gas flow rate on significant factors such as velocity distribution which characterize the discharge flow field are discussed quantitatively. The way of estimation of the velocity distribution in the discharge flow field under given conditions is made clear. Additionally, new information is obtained about important factors for the discharge flow field : e.g., the shear rate based on the mean velocity takes larger values than that based on the fluctuating velocity.
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  • Itaru Tamura, Hirokazu Nishitani, Eiichi Kunugita
    1992 Volume 18 Issue 4 Pages 502-509
    Published: July 10, 1992
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The rolling schedule algorithm includes the following operations. An optimal decision is formed by solving a multi-period optimization problem over a finite time horizon and implementing only the first period's decision. One period later, the multiperiod model is updated through measurements and the operation is repeated. The significance of the rolling schedule is accepted widely, but there have been few analytic studies of robustness in operational research because of the difficulty in description of the solution. This paper unveils some general properties of the rolling schedule for a simple case by using the digital control theory.
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  • Fumimaru Ogino, Masahiro Kamata, Keishi Shimokawa
    1992 Volume 18 Issue 4 Pages 510-514
    Published: July 10, 1992
    Released: November 12, 2009
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    Velocity profiles of fluid in a spouted bed were measured by using a laser doppler velocimeter. The fluid used was a liquid, the refractive index of which was adjusted to that of the solid particles. Results indicate that 1) the normalized velocity profiles are independent of Reynolds number, 2) the spouted bed has a recirculating zone similar to that of the flow through a sudden expansion, and 3) the diameter of the spout increases with increasing height.
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  • Fumimaru Ogino, Masahiro Kamata, Keishi Shimokawa, Kaichiro Mishima, S ...
    1992 Volume 18 Issue 4 Pages 515-520
    Published: July 10, 1992
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Motion of solid particles in a spouted bed was visualized by using neutron radiography. Trajectories and velocity profiles of particles in the annular region were obtained by radiography. Results indicate that both the trajectory and radial profile of particle velocity normalized by the mean velocity of fluid through the nozzle are almost independent of height of packing and Reynolds number.
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  • Junji Shibata, Youichi Kurihara
    1992 Volume 18 Issue 4 Pages 521-527
    Published: July 10, 1992
    Released: November 12, 2009
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    Extraction behavior of Ti (IV) and other metal ions, such as Fe (III), Fe (II), Cu, Zn, Co, Mn, Mg and Al from acidic solutions was studied in order to separate Ti (IV) from aqueous solutions. Extractants used were three kinds of tri-alkylphosphine oxide with the trade names Cyanex 921, Cyanex 923 and Cyanex 925.
    The extraction of Ti (IV) from hydrochloric acid solutions increases with an increase in hydrochloric acid concentration. High extraction of Ti (IV), 9099% extraction, is reached at a hydrochloric acid concentration of 8 mol/dm3. Other metal ions are also extracted well at the same acid concentration. In the extraction from sulphuric acid solutions, Ti (IV) is sufficiently extracted in a wide range of sulphuric acid concentration. Extraction of Fe (III) and Fe (II) is very low, the extent being below 20% over a wide concentration range of sulphuric acid. Other metal ions are not extracted at all with any phosphine oxide. The extraction characteristics are suitable for a separation and purification process for high-purity titanium oxide. For example, an counter-current extraction process with 23 stage extractions ane 8-stage strippings can produce high-purity Ti (IV) solution from the process solution in the production of titanium oxide by a conventional sulphuric acid method.
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  • Masato Tanaka, Hideyo Tanaka, Isao Kimura, Natsukaze Saito
    1992 Volume 18 Issue 4 Pages 528-534
    Published: July 10, 1992
    Released: November 12, 2009
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    Suspension polymerization of styrene was performed using calcium tertiary phosphate as the suspension stabilizer. The effect of divided addition of the suspension stabilizer on particle size distribution was mainly investigated.
    Transient mean droplet diameters, final particle size distributions and final mean particle sizes were strongly affected by the conversion at which the suspension stabilizer was added. Divided addition of the suspension stabilizer at conversions of 0.45 and 0.65 was found to produce polymer particles of the most uniform size.
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  • Ikuya Imamura, Yoshinori Kutsuwa, Hisayoshi Matsuyama
    1992 Volume 18 Issue 4 Pages 535-538
    Published: July 10, 1992
    Released: November 12, 2009
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    A method is proposed for judging the existence of a quaternary azeotrope in a quaternary system at constant pressure by use of a topological condition on the vector field composed of residue curves. Given the boiling temperatures of pure materials and the compositions and bubblepoint temperatures of binary and ternary azeotropes in the system, the proposed method enables us to determine the possible region of the quaternary azeotrope. The procedure for reducing that region is demonstrated by applying it to the acetone-methylacetate-methanol-hexane system.
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  • Chikao Arai, Kazunori Hozumi, Yoshiki Sano, Hideomi Matsuda
    1992 Volume 18 Issue 4 Pages 538-541
    Published: July 10, 1992
    Released: November 12, 2009
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    To contribute to the interpretation of liquid-phase adsorption, diffusion coefficients were measured for many kinds of aromatic compounds in water, methanol, ethanol and 1-propanol at 298.2 K by the schlieren cylindrical lens method.
    The data were compared with estimated values from the Wilke-Chang correlation. It is shown that the diffusivities of phenols and aromatic amines are smaller than the estimated values, while those of sulfonic acids are larger. The mean deviation of the estimated values from the observed ones was found to be 11 % in the aqueous solutions and 23 % in the alcohols.
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  • Yoshinori Kutsuwa, Hirokazu Nishitani, Eiichi Kunugita
    1992 Volume 18 Issue 4 Pages 541-545
    Published: July 10, 1992
    Released: November 12, 2009
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    Fuzzy control was applied to a mixed-culture system that is a multivariable process including nonlinear relationships. A set of control loops was determined by the loop-pairing method and a fuzzy controller was designed for each loop. The fuzzy controllers were tuned with reference to the conventional multivariable control system design method for linear processes.
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  • Yasuo Hirose, Hiroshi Tachibana, Yuji Kamata
    1992 Volume 18 Issue 4 Pages 546-549
    Published: July 10, 1992
    Released: November 12, 2009
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    The effects of the dimensions of submatrices on distillation calculations based on the Newton-Raphson method were studied by comparing two algorithms whose submatrix dimensions are (m+2) [algorithm I] and (2m+3) [algorithm II], where m means number of components. It was found that algorithm II is superior to algorithm I from the standpoint of cpu time, convergence and maintenance of the program. A guiding principle of programming is given on the basis of this work and the previous ones.
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  • Haruo Yamashita
    1992 Volume 18 Issue 4 Pages 549-552
    Published: July 10, 1992
    Released: November 12, 2009
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    The new index in which the contribution of symmetry of hydrocarbon groups is especially taken into account on calculating molecular connectivity index is proposed. Correlation between chemical structures and catalytic activities on the reaction of 1-bromooctane with thiophenol catalyzed by quaternary ammonium ions is analyzed by using this index. It is predicted that tetraoctylammonium bromide is more effective in the reaction system. The kinetic study indicates that the prediction proves true.
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