KAGAKU KOGAKU RONBUNSHU
Online ISSN : 1349-9203
Print ISSN : 0386-216X
ISSN-L : 0386-216X
Volume 16 , Issue 2
Showing 1-38 articles out of 38 articles from the selected issue
  • Yutaka Matsumoto, Yoshiyuki Totsuka, Seiichi Yamamoto, Yoshio Kawashim ...
    1990 Volume 16 Issue 2 Pages 197-203
    Published: March 10, 1990
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Thermophilic fermentation suspension of night-soil was filtrated in cross-flow mode using various thermostable membranes. The influence of operating conditions on flux was studied.
    Limiting fluxes were obtained, and higher feed velocity and lower feed concentration resulted in a higher limiting flux. Difference in membrane module structure had a great effect on this limiting flux. The fluxes obtained with a flat membrane module (NTR-C70-F) were three to five times higher than those with a tubular one.
    A gel layer was formed on the membrane surface. This layer had a large permeate resistance, and its specific filtration resistance was about 4.5×1015m·kg-1 at 300 kPa.
    In a long-term pilot test, the permeate flux was stable at about 1.6m3·m-2·d-1 at a feed velocity of 2m·s-1.
    It was also found that the permeate solution contained a great deal of NH4-N and Cl- compared with commercial hydroponic culture solution.
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  • Hiroyuki Ito, Yoshito Umeda, Yasuhisa Nakamura, Tetsuo Watanabe, Takaa ...
    1990 Volume 16 Issue 2 Pages 204-210
    Published: March 10, 1990
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    To establish an accurate design method for industrial furnaces from the viewpoint of heat transfer, we carried out three-dimensional unsteady heat transfer analysis for a practical-size heat treatment furnace equipped with radiant heaters. We applied three packaged programs, STREAM, MORSE and TRUMP, to analyze a combined heat transfer problem of radiation, conduction and convection. We also carried out experiments in heating of a bolts-packed model as an actual work.
    We found that air flow swirled in the furnace. As for the temperature in each part in the furnace, analytical results generally were in good agreement with the experimental ones. This suggests that our analysis method is useful in the fundamental heat transfer design of a practical-size industrial furnace with an actual work, such as a bolts-packed model. For the temperature distribution in the work, analytical results were also in good agreement with experimental ones. Consequently, it was found that the heat transfer in the bolts-packed work could be described with effective thermal conductivity.
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  • Masaki Minemoto, Shigekazu Hatano, Yoshihiro Kita, Naoyuki Kamishima, ...
    1990 Volume 16 Issue 2 Pages 211-218
    Published: March 10, 1990
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Within the closed system of a manned space station or other such environment, it is necessary to establish a life support system that recovers CO2 produced metabolism and produces O2. As a step toward this goal, we performed a basic test and a continuous reduction test, and also conducted simulation calculations with respect to the Bosch reduction reaction which changes CO2, removed from the air and concentrated, into solid carbon and water.
    We then selected the optimum conditions by examining the influence of each parameter on CO2 reduction performance. The results indicated that to improve the Bosch reaction effectively, two-stage reactions (i.e. 1st and 2nd) at different temperatures and gas circulation are both required. In addition, it has become clear that the optimum operating conditions for reduction of that CO2 produced by two persons are set temperatures for the 1st and 2nd reactors of 1, 200K and 850K respectively, a catalyst filling column height of 0.1 m for each, and a circulating gas flow rate of 0.75 m3 (STP) h-1.
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  • Yasuo Hatate, Takahisa Nakaue, Tatsuo Imafuku, Yoshimitsu Uemura
    1990 Volume 16 Issue 2 Pages 219-226
    Published: March 10, 1990
    Released: November 12, 2009
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    Fine polymer particles, having large surface-to-volume ratio, exhibit particular behavior under triboelectricity because they are controlled by the Coulombic force rathe than by qravity. This property is applied in various industrial areas such as electric photography. However, the effects of chemical composition, surface condition, particle size, and particle shape on the triboelectric properties have not beer so clearly investigated.
    In this study, several kinds of polymer microspheres, almost uniform in size, were prepared by suspension polymerization. They were charged by friction with ferrite spheres to study the effect of physical properties of polymer microspheres on their triboelectricty.
    The following results were obtained.
    (1) The electrostatic capacities increased with decreasing particle size. Such tendency is consistent with Schaffer's empirical equation.
    (2) The electrostatic capacities increased with increasing cross-linking sites and molecular weight of polymer microspheres.
    (3) The functional groups of the polymer microsphere strongly affected the electrostatic capacity. Higher electrostatic capacities were obtained for polymer microspheres having stronger polarity.
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  • Yoshitomo Hanakuma, Takashi Sasaki, Eiji Nakanishi
    1990 Volume 16 Issue 2 Pages 227-231
    Published: March 10, 1990
    Released: November 12, 2009
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    In a continuous polymerization reactor, product grade alternation is quite important from the viewpoint of lower production loss, uniform production quality and labor saving. The above alternation step should proceed as quickly and stably as possible for good process economic.
    A model predictive control system is designed for the satisfactory grade alternation step in a continuous polyethylene polymerization reactor. The ARX model was applied to a reactor dynamics approximation using the Recursive Maximum Likelihood method. Actual results showed that the control system so developed is sufficient in practice for product grade alternation in a continuous polyethylent polymerization reactor.
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  • Mitsutaka Kitamura, Kunio Ikemoto, Yuji Kawamura, Tasuku Nakai
    1990 Volume 16 Issue 2 Pages 232-238
    Published: March 10, 1990
    Released: November 12, 2009
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    Surface reaction kinetics in the crystal growth process of ammonium sulphate is investigated by estimating the interfacial concentration on the single crystal. It is clear that both NaN and BCF models can be applied to each surface reaction process of (100), (010) and (001) faces in pure solution with the same accuracy. In the presence of Cr3+, the growth rate remarkably decreases with Cr3+ concentration and finally stops at a concentration of 2ppm for (010) face, 2.5ppm for (001) face and 3ppm for (100) face. Under a constant concentration of Cr3+, crystal begins to grow when the supersaturation becomes larger than a critical value, after which the growth rate increases predominantly with supersaturation and attains the maximum, the value in the pure solution.
    As for the mechanism of the impurity effect, adsorption of Cr3+ on steps of the crystal surface is considered. Bow-shaped macrosteps were confirmed by microscopic observation. Applying the model of Cabrera and Vermilya, the distance between the adsorbed Cr3+ ions was roughly estimated as 14 nm for (100) and (010) faces, and 18 nm for (001) face.
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  • Kazuhiro Yamade, Tetsuya Fukaya, Susumu Fukushima
    1990 Volume 16 Issue 2 Pages 239-244
    Published: March 10, 1990
    Released: November 12, 2009
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    The productivity of secondary metabolite as ubiquinon-10 was increased by using an immobilized tobacco callus, Nicotiana tabacum Cultivar Xanthi Ova., in Ca-Al alginate. It was confirmed that this immobilized callus was useful for a continuous culture because a dispersed callus was obtained, and that the specific growth rate and the affinity of the substrate and callus were increased. The growth model of this callus was approximated by Contois's equation. Values of the callus and glucose concentrations estimated from those at the steady state for each residence time agreed with the observed data for unsteady-state operation.
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  • Atsushi Morihara, Syuntaro Koyama, Syunsuke Nogita
    1990 Volume 16 Issue 2 Pages 245-251
    Published: March 10, 1990
    Released: November 12, 2009
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    The effect of momentum on the residence time of particles with downward swirling was studied in model apparatus of a pilot-scale swirling entrained bed.
    In a single-chamber gasification furnace in which pulverized coal is both gasified and combusted, the efficiency of gasification is dominated by the particle residence time and the region occupied by the particles.
    The length and the residence time increased with decrease of the furnace exit diameter and of the rotational diameter at lower burners, with increase of the velocity at upper burners, and with increase of the flow rate at upper burners.
    The effects on particle residence time were made clear using a momentum parameter α, which was determined as a function of the velocity, the flow rate, and the rotational diameter of lower and upper burners.
    The length of downward swirl can be derived from α, and its relation to the residence time was obtained.
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  • Sotoji Hiragi, Chikao Kanaoka, Kazuhito Yamada
    1990 Volume 16 Issue 2 Pages 252-258
    Published: March 10, 1990
    Released: November 12, 2009
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    To clarify the functional relationship between the morphology of particle accumulation on a fiber and the collection mechanism, the morphology was experimentally investigated when either mechanical or electrostatic effect was prevailing.
    In mechanical collection, particles accumulated on a whole fiber surface in the diffusion-controlling condition and then deposition on the rear side decreased as the convective effect (Pe) increased. When the inertial effect (Stk) was dominating, all particles were captured on the front side of the fiber. Particle size was also found to affect the irregularity of the shape, i.e., the larger the relative particle diameter to the fiber diameter (R), the more irregular was the shape.
    In electrostatic collection, particles formed chain-like deposits irrespective of their charging states for small accumulation, but the electrostatic effect decreased as the accumulation increased when dielectric particles were captured on a polarized fiber. The shapes of the accumulation of noncharged and charged particles were confirmed qualitatively by taking account of the electrostatic forces. The shapes of the former were strongly dependent on gradient and pearl chain forming forces, those of the latter on Coulombic and pearl chain forming forces.
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  • Tetsuji Yasuda, Hiroshi Komiyama
    1990 Volume 16 Issue 2 Pages 259-267
    Published: March 10, 1990
    Released: November 12, 2009
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    A new reaction system for low-temperature deposition of carbon films was proposed and its deposition mechanism was investigated. The carbon films were deposited at a substrate temperature of 343573K by irradiating a CH4-Cl2 mixture with ultraviolet light. The deposition rate was proportional to th sum of concentrations of methyl and choromethyl radicals, which were estimated by modeling the gas-phase process. The sticking probability of these radicals was 6×10-4at a substrate temperature of 343K. The deposition rate (1060nm/h) decreased with increasing substrate temperature, showing a negative activation energy of 1013kJ/mol. This temperature dependence was examined on the basis of a simple scheme in which those radicals were incorporated into the film via weakly adsorbed state.
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  • Hidefumi Toyohara, Yuji Kawamura
    1990 Volume 16 Issue 2 Pages 268-274
    Published: March 10, 1990
    Released: November 12, 2009
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    To investigate the fluidizing characteristics of a tapered bed of binary particle mixtures, the pressure drop, particle movement and segregation behavior were examined. Glass beads of the same density but various diameters were used as binary particle mixtures belonging to Geldart groups B and D.
    It was found that fluidizing behavior in the tapered bed could be classified into that in the core region and that in the side region at fluid velocities between incipient fluidization and perfect mixing condition. Characteristic particle movements were observed in these regions and were found to be dependent on fluid velocity. Especially in the core region, particle separation occurred and jetsam particles tended to concentrate into the bottom of the core to form a jetsam-rich layer. This segregated layer failed to fluidize under a certain bed condition, and then “core-type segregation” was observed.
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  • Katsuo Komori, Terumi Inagaki
    1990 Volume 16 Issue 2 Pages 275-279
    Published: March 10, 1990
    Released: November 12, 2009
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    Experiments were performed to investigate the effect of suction through a slit on the characteristics of heat transfer. A suction slit 160 mm wide and 3 mm long was arranged in a laminar boundary layer formed on a flat plate and across the main stream at a distance 100 mm downstream from the leading edge of the flat plate. Heat transfer coefficients and characteristics of flow were measured for air flow with a Reynolds number from 2.0 x104 to 7.0 x105 and with a suction rate from 0.01 to 0.2.
    Conclusions obtained are as follows. The local heat transfer coefficient increases remarkably near the slit, and after a decrease within the stagnant region of the flow it gradually approaches the value at laminar flow.
    The starting point of transition from laminar to turbulent tends to shift downstream with the increase in suction rate. The turbulent transition in the average heat transfer coefficient starts somewhat earlier than that in the flow. The velocities in the boundary layer are influenced markedly by suction and are accelerated, especially at the immediate rear of the slit. The turbulent transition in flow develops for the inner layer from the outer edge of the shear layer.
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  • Yoshinobu Kawano, Yoshiharu Yoshikawa, Takanao Matsui, Kazuo Kondo, Fu ...
    1990 Volume 16 Issue 2 Pages 280-285
    Published: March 10, 1990
    Released: November 12, 2009
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    Distribution equilibria of succinic acid in aqueous solution into organic solvents and in organic solutions of tri-n-octyl amine were measured for various concentrations at 303K. The.succinic acid dissolved as the monomeric species in organic solvents. The distribution coefficients of the acid varied in the order of hexane < benzene < chloroform < methyl isobutyl ketone. The acid hardly dissolved in carbon tetrachloride. The species formed and the equilibrium constants for the reactions between the acid, A, and the ammine, B, were estimated by graphical analysis. The experimental results were interpreted by the following reaction models.
    (1) The amine in organic solution reacts with the acid to form AB species in the solvents.
    (2) The species AB further reacts with A or AB to form (AB)5 in benzene or A2B in methyl isobutyl ketone.
    The formation constants for the species were estimated by use of the above reaction models.
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  • Hitoki Matsuda, Katsuhisa Kumazawa, Kazutaka Miyoshi, Noriyuki Kobayas ...
    1990 Volume 16 Issue 2 Pages 286-294
    Published: March 10, 1990
    Released: November 12, 2009
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    Cobalt oxide (CoO) fine particles were prepared by spray-pyrolysis from four aqueous solutions of different cobalt salts : CoSO4 -7H2O, Co (NH4)2 (SO4)2·6H2O, Co (CH3COO)2·4H2O and Co (NO3)2.6H2O.
    It was found that CoO fine particles with a diameter smaller than 1.0μm could be made from all of the cobalt salt solutions studied under the present experimental conditions (concentration range : 0.051.0kmol·m-3, decomposition temperature : 1133.2K ; and residence time : 1.53.0s). The CoO particles produced were different in shape and had different particle size distributions. Spherical fine particles with porous structure were prepared from CoSO4·7H2O and Co (NH4)2 (SO4)2·6H2O solutions. Hollow spherical fine particles were obtained from Co (NO3)2·6H2O. The fine particles from Co (CH3 COO)2·4H2O solution were composed of chain-like agglomerates of ultrafine particles below 0.1 μm in diameter. It was concluded that formation mechanisms of CoO fine particles differ according to the feed cobalt salt solution.
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  • Akira Ito, Kiyoshi Shirasuna, Touru Iizuka, Michihiro Fujii
    1990 Volume 16 Issue 2 Pages 295-301
    Published: March 10, 1990
    Released: November 12, 2009
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    A membrane separation process for recovery of organic vapors from the air was studied experimentally, using silicone rubber hollow-fiber membranes. Permeabilities of vapors of pure acetone and Freon 113 were measured and the correlations of these values with pressure were presented. Permeation data for the gas mixtures (nitrogen gas containing 1-2% of these vapors) were compared with models expressed by differential equations for the flow rates of gas and vapor along the membrane module. These results lead to useful information for the design of a membrane separation process for recovery of these organic vapors from the air.
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  • Suk-Ho Yoon, Toshiro Murase, Eiji Iritani, Tetsushi Suzuki, Shinya Nak ...
    1990 Volume 16 Issue 2 Pages 302-309
    Published: March 10, 1990
    Released: November 12, 2009
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    The transient behaviour of precoat filtration, where dilute slurry was clarified through a cake of filter-aid, was studied under constant pressure using several kinds of diatomaceous precoat layer.
    The separation of supended solids, including very fine particles, was viewed in relation to the progressive change in pore structure with clogging. The process consisted of two stages : the initial stage, in which the solids capture occurred primarily through adhesion of diatomite grains and screening in the pore space ; and the second stage, in which screening predominates. The effect of precoat filtration conditions on filter performance was evaluated in terms of a newly defined factor ζ which takes into account the applied pressure and the properties of precoat cake as well as original slurry. The equation correlating the factor with the deposition rate of solids was determined at each stage of separation. The flow rate of finished filtrate was also determined to be a function of the deposition in order to estimate the time-dependency of the turbidity and the flow velocity of filtrate. It was shown that the calculated results, based on the operational factor ζ, are in agreement with those obtained from the filtration experiments with CaCO3 and polystyrene latex slurry.
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  • Yoshihiro Hashimoto, Akihiro Yoneya, Yoshitaka Togari
    1990 Volume 16 Issue 2 Pages 310-316
    Published: March 10, 1990
    Released: November 12, 2009
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    Since a distillation column is a typical nonlinear process, decoupler errors are caused by changes in operating conditions. The authors have examined the effect of the selection of manipulated variables on the interaction between composition control loops and the decoupler sensitivity. In this paper, the effect of the selection of manipulated variables on the system changes in altering the operating condition is discussed. Several useful results for design of distillation control were obtained. Although decoupler sensitivity of material balance control is much lower than that of the convetional control, the system changes of material balance control due to change in operating conditions are identical to those of conventional control. A control scheme that utilizes reflux ratios in the top and the bottom of the column as manipulated variables of composition control is less sensitive than conventional control, material balance control or Ryskamp's control.
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  • Yuji Sano, Hiromoto Usui, Hideo Sakata
    1990 Volume 16 Issue 2 Pages 317-321
    Published: March 10, 1990
    Released: November 12, 2009
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    Characteristic velocities in mixing vessels using paddle impellers with and without baffle plates are obtained from the power numbers by using the friction factors for smoothed pipe and for rough pipe with repeated ribs, under the condition of equaldissipation energy between pipe flow and mixing vessel flow. The characteristic velocity is expressed by a single correlation equation, including various paddle dimensions and baffle conditions. The characteristic velocity presents well the power numbers and the heat transfer coefficients of the mixing vessels.
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  • Mitsuyuki Nakajima, Masatomi Harada, Ryohei Yamazaki, Genji Jimbo
    1990 Volume 16 Issue 2 Pages 322-328
    Published: March 10, 1990
    Released: November 12, 2009
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    In the range of gas velocity from bubbling to turbulent fluidized beds, the radial and axial profiles of bubble fraction were measured together with variations of axial pressure fluctuation through a bed and the pressure gradient at several heights in the bed.
    The bed stucture was examined on the basis of bubble fraction and pressure data, and the following was found.
    In the transition to the turbulent fluidized bed, the increase of bubble phase, which is caused by the increase of gas velocity, is moderated and the emulsion phase expands more than that in the bubbling condition. Gas velocity at which the emulsion phase begins to expand, uc', is estimated by the correlation Rec' =0.663 Ar0.467.
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  • Tomohiko Furuhata, Hideyuki Aoki, Shoji Tanno, Takatoshi Miura, Shozab ...
    1990 Volume 16 Issue 2 Pages 329-334
    Published: March 10, 1990
    Released: November 12, 2009
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    To investigate the change of flow characteristics in a duct caused by introducing two-stage combustion (TSC) air, TSC air (80 Nm3/hr.) was introduced tangentially at an axial position of x/D=0.8 through the circumference of a circular duct (0.5m I.D.×2.0m length) of acrylic resin. Two components (axial and tangential) of the mean velocities at x/D=0.5 and 1.5 were measured using a laser-doppler-anemometer.By combining the k-ε two-equation model with a model developed for TSC air, the flow in the duct was analyzed numerically in cylindrical coordinates to compare the results with the measured turbulent flow quantities. Numerical results agreed well with experimental ones and the model developed for TSC air was thus found to be appropriate. These results did not agree, however, with the results by introducingTSC air through one tube as applied to a practical furnace. Three-dimensional analysis must therefore employed.
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  • Ryoichi Kuboi, Kazunori Hashimoto, Isao Komasawa
    1990 Volume 16 Issue 2 Pages 335-342
    Published: March 10, 1990
    Released: November 12, 2009
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    Reverse micellar bulk liquid membrane was successfully applied to the separation of proteins with high selectivity by utilizing electrostatic interaction and/or steric interaction (size exclusion effect) between micelles and proteins. Highly selective uphill transport of proteins through the liquid membrane from one aqueous phase to another can be achieved by manipulating pH, concentration of KCl in both aqueous phases and initial water content in the membrane phase and also by selecting an anionic or cationic surfactant (AOT or CTAB). This is effected by the differences in the physical properties of the proteins to be separated such as isoelectric point, surface charge and molecular weight.
    Denaturation of proteins, mainly caused by complex formation with AOT molecules at low concentration of KCl in the aqueous phase for recovery, is small compared with that encountered in conventional batch extraction. The liquid-membrane separation system was further extended to the separation method utilizing the difference of transfer rate of proteins concerned. The combined liquid-membrane system with both AOT and CTAB membranes is also effective for the simultaneous separation of proteins.
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  • Kyu Suk Hwang, Shigeyuki Tomita, Eiji O'shima
    1990 Volume 16 Issue 2 Pages 343-353
    Published: March 10, 1990
    Released: November 12, 2009
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    A methodology for developing a system which can synthesize operating procedure including parallel operations and considering time constraints is proposed. A computerbased system based on this methodology was developed and applied to the start-up of a practical chemical plant to evaluate the effectiveness of the methodology. Heuristic knowledge, which is used for testing if current SCOPE is ready to be operated in parallel, is organized in the form of a prolog-like knowledge base. The system looks for all SCOPEs, which can be operated in parallel at each step of generation of operating procedure by checking if the circumstantial states of units and lines around the current SCOPE satisfy the knowledge base.
    On the other hand, a network structure is introduced to represent the parallel operations and some constraints such as time limit. This network structure is used to show the process of activating SCOPEs, which is required for leading the state of the plant to the goal state. By using this network structure, the starting time of operation of each unit, valve and functional utility is decided, taking account of time constraints of SCOPE activation. The operating sequence including parallel operations can be generated by using these starting times as a guideline for synthesizing the operating procedure.
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  • Masayoshi Sadakata, Akira Yamaguchi, Takeshi Sakai, Daiqing Zhao
    1990 Volume 16 Issue 2 Pages 354-360
    Published: March 10, 1990
    Released: November 12, 2009
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    For scale-up of a higher-reaction rate system such as a practical combustion system, the turbulent mixing time becomes an important factor. For these reaction system, Sadakata et al. pointed out that keeping residence time constant is essential for scale-up, to ensure the analogy of mixing time as the scale of the system is changed.
    In the present work, the effects of the Reynolds number on the turbulent characteristics of a free jet issuing from circular tube nozzles were studied experimentally by means of a hot-wire anemometer, and the adequency of the proposed scale-up law was examined.
    The hypotheses assumed before deriving the scaling law were confirmed adequately when Reynolds number was larger than 105. It was found that turbulent characteristics such as relative turbulent intensity and integral scales were not affected by a Reynolds number of free jet over 105. Futhermore, the rate control of turbulent mixing is the rate of turbulent energy transfer from energy containing lower-wave number vortex to higher-wave number eddy.
    As the results, the analogy of both the flow pattern and mixing time were attained simultaneously when the Reynolds number of a free jet was held above 105. Therefore, it is suggested that the lowest limitation to ensure constant mixing time is Re = 105 regarding the scale-up law for a combustion system.
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  • Itaru Ichihara, Kunihiko Takeda, Hatsuki Onitsuka
    1990 Volume 16 Issue 2 Pages 361-367
    Published: March 10, 1990
    Released: November 12, 2009
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    The multistage separation system using adsorption and desorption is difficult to enlarge because the imaginary equivalent height (Hq) is less than a few millimeters. Several experiments with uranium enrichment as a typical multistage separation process showed that separation efficiency was in the range of 3.2 to 4.4 %, even when the contributions of adsorbent and chemical reactions to Hq were taken into account. The diffusional effects of packed beds were evaluated by the pulse response method and were represented by an imaginary equivalent height in the mobile phase (Hm). A modified Gaussian distribution was used for this analysis. It was found that the scattering of separation efficiency is caused by the diffusional effects of packed beds. The values of Hm are in the range of 0.4 to 0.6 mm, or about 30 to 40 % of Hq.
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  • Hidetoshi Sekiguchi, Atsushi Kanzawa, Takuya Honda
    1990 Volume 16 Issue 2 Pages 368-375
    Published: March 10, 1990
    Released: November 12, 2009
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    Numerical calculations were performed to investigate the reaction fields in the thermal plasma synthesis of NO and the thermal plasma decomposition of CO2. Models were based on the solutions of one-and two-dimensional mass, momentum, energy, and species conservation equations. The calculated results for both reaction systems in the two-dimensional model agreed well with experimental results. The results for the one-dimensional model also showed that the one-dimensional model was adequate for CO2 decomposition, but not for NO synthesis. Comparison of these reaction systems suggested that the validity of the solution for the one-dimensional model was affected by the temperature dependency of the decomposition rate of products. The axial conversion profiles obtained determined the most suitable position of the quenching.
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  • Motoyuki Suzuki, Cho-hee Yoon
    1990 Volume 16 Issue 2 Pages 376-383
    Published: March 10, 1990
    Released: November 12, 2009
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    Phosphorus release/uptake in microorganisms under anaerobic/aerobic conditions were studied by using a laboratory sequential batch reactor (SBR) system.
    In particular, the behavior of phosphorus and organic carbon in microorganisms under anaerobic conditions was experimentally investigated in this work.
    The rate of phosphorus release from microorganisms can be described as a firstorder reaction with respect to their phosphorus content. The rate constant of phosphorus release at the anaerobic stage was given by a function of biodegradable organic carbon substrate concentration in the form of a modified Monod-type equation.
    Intracellular phosphorus released at anaerobic stages was found to be mainly soluble phosphorus that can be extracted by hydrochloric acid.
    The initial amount of organic carbon substrate adsorbed onto microorganism flocs can be approximated by the Freundlich equation.
    Biodegradable organic carbon substrate was almost completely taken up by microorganisms at the anaerobic stages and the rate of its uptake can be described as a first-order reaction. Finally, it was found that the difference in phosphorus accumulation in microorganisms was attributable to the ability of accumulation of organic carbon.
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  • Toshiyuki Komori, Shuzo Ohe
    1990 Volume 16 Issue 2 Pages 384-387
    Published: March 10, 1990
    Released: November 12, 2009
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    Vapor-liquid equilibrium data are reported for the cyclohexane-n-heptane system at atmospheric pressure. This system shows slight deviations from an ideal solution. The activity coefficients were calculated from the experimental data, taking the nonideality of the vapor phase into account with Tsonopoulous's equation.
    Materials were distilled to a purity of 99.9% and no significant impurities were detected by gas chromatograph.
    The observed data were well correlated using activity coefficient equations (van Laar, Margules, Wilson) and were found to be thermodynamically consistent by the method of Herington.
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  • Tadaatsu Ido, Yuuki Kitamura, Shigeo Goto
    1990 Volume 16 Issue 2 Pages 388-391
    Published: March 10, 1990
    Released: November 12, 2009
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    The optimum condition for use of polyethylene glycal as a phase transfer catalyst in a continuous process was investigated. A third phase (referred to as middle phase) appeared between toluene containing polyethylene glycol (organic phase) and aqueous solution of potassium hydroxide (aqueous phase) by addition of methanol. However, the aqueous phase disappeared with further addition of methanol.
    The optimum condition was that of the least possible quantity of water, and the concentration of catalyst in the organic phase became just zero by addition of methanol.
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  • Tsuneaki Fujiwara
    1990 Volume 16 Issue 2 Pages 391-393
    Published: March 10, 1990
    Released: November 12, 2009
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    In man-made leather production, DMF is important as a solvent of polyurethane and then is discharged as aqueous solution. DMF is usually recovered by vacuum distillation from the solution, but in this step DMF is decomposed hydrolytically into formic acid and dimethylamine. To suppress DMF decomposition, the distillation temperature must be lowered. Experiments were carried out on DMF decomposition rate to confirm the validity of vacuum distillation, and the results showed the temperature dependence of DMF decomposition.
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  • Toshio Kajiuchi, Naohiro Shiragami
    1990 Volume 16 Issue 2 Pages 394-396
    Published: March 10, 1990
    Released: November 12, 2009
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    Circulation flow in a peristaltic bioreactor was studied experimentally by the flow visualization technique. The circulation flow induced by peristaltic motion was observed from the particle trajectories. The circulation flow was expressed quantitatively as the characteristic dimensions of such flow. From the distributions of these characteristic dimensions in the bioreactor it is found that the flow behavior in the bioreactor was composed of backward flow with a small loop motion in the center region and forward flow with a large loop motion in the neighborhood of the peristaltic wall.
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  • Kunio Atsumi, Toshio Makino, Masahiro Terada, Toshiro Murase, Eiji Iri ...
    1990 Volume 16 Issue 2 Pages 397-400
    Published: March 10, 1990
    Released: November 12, 2009
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    Baffle effects on the Taylor vortex flow and the rotor torque were studied experimetally in the chamber of a cylindrical dynamic filter. The Taylor vortex occured mainly in the annular space between the rotating cylinder and the baffles. Empirical correlations using the critical Reynolds number, the wave length of the vortex, and the frictional coefficient of the rotor were proposed as individual functions of those under nonbaffle conditions and a newly defined clearance ratio. It is suggested that the baffles in the dynamic filter chamber cause a high liquid shear sufficient to sweep filter cake from the inner cylindrical medium.
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  • Kenji Kawasaki, Akira Matsuda, Tetsuo Ide, Toshiro Murase
    1990 Volume 16 Issue 2 Pages 401-403
    Published: March 10, 1990
    Released: November 12, 2009
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    The cell density and dry solids fraction of three kinds of excess activated sludge (unfrozen, fast-frozen and slow-frozen sludges) were evaluated from the equilibrium heights of the sediments under centrifugal settling. These values of the frozen sludges were greater than those of the unfrozen sludge, and therefore it was found quantitatively that the sludge cells were dewatered due to freezing and thawing. Also, the volume fraction of cells in the slow -frozen sludge floc was found to be twice as large as that in unfrozen and fast -frozen sludges.
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  • Yorishige Matsuba, Teruo Takahashi, Yoshiro Kitamura
    1990 Volume 16 Issue 2 Pages 404-407
    Published: March 10, 1990
    Released: November 12, 2009
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    Liquid-liquid equilibria were investigated for a system of acetonitrile (10wt% water), n-heptane and cod oil fatty acids containing highly unsaturated species such as eicosapentaenoic acid. The experimental data were well correlated by the method previously developed for C18 components. In this correlation, the concentration of the specific component in the acetonitrile phase can be estimated from the state of n-heptane phase, i.e. the total concentration of fatty acids and the solventfree mole fraction of the related component. The correlation parameters were evaluated and summarized for the major components contained in the cod oil fatty acids.
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  • Masaaki Teramoto, Masato Nakatsu, Noriaki Ohnishi, Hideto Matsuyama
    1990 Volume 16 Issue 2 Pages 407-410
    Published: March 10, 1990
    Released: November 12, 2009
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    Experiments on the permeation of lead (II) through supported liquid membranes containing di (2-ethylhexyl) phosphoric acid as a carrier dissolved in n-dodecane and experiments on the extraction equilibrium of the present lead -carrier system were performed. The extraction reaction was found to be expressed as follows :
    Pb2+1.75 (HL)2_??_ccomplex+2H+
    where (HL)2 is the dimer of the carrier. Experimentally observed permeation rates of lead were quantitatively explained by a permeation model in which the mass transfer in both the aqueous feed phase and the liquid membrane phase and the extraction equilibrium at the feed-liquid membrane interface are considered.
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  • Yoshinobu Kawano, Kenichiro Hanamura, Tadashi Hano
    1990 Volume 16 Issue 2 Pages 411-414
    Published: March 10, 1990
    Released: November 12, 2009
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    Adsorption equilibrium of polar acid compounds on activated carbons were measured over a wide concentration range. The results in the low concentration range were interpreted by use of the Langumuir adsorption isotherm. However, the B.E.T. equation explained adsorption equilbria studied over the entire concentration range. Monolayer and multiple-layer adsorption constants obtained by the above models were also independent of the type of organic acids adsorbed.
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  • 1990 Volume 16 Issue 2 Pages e1a
    Published: 1990
    Released: November 12, 2009
    JOURNALS FREE ACCESS
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  • 1990 Volume 16 Issue 2 Pages e1b
    Published: 1990
    Released: November 12, 2009
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    Download PDF (87K)
  • 1990 Volume 16 Issue 2 Pages e1c
    Published: 1990
    Released: November 22, 2010
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