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KUNIO KATAOKA
1999 Volume 25 Issue 4 Pages
501-509
Published: July 10, 1999
Released on J-STAGE: November 12, 2009
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Nonlinear phenomena in a flowfield where chemical processes proceed are discussed from achemical engineering viewpoint of how to design and precisely control complex chemical processes and systems. Two kinds of reactors are studied : continuous stirred tank reactor (CSTR) and Taylor vortex flow reactor (TVFR). After discussing the mixing characteristics of the flowfield, two kinds of complex chemical reaction systems are considered : the Belousov-Zhabotinskii (BZ) reaction and emulsion polymerization. The complex bifurcating behavior of chemical oscillations in the BZ reaction is demonstrated in a TVFR as well as in a CSTR. The mechanism for self-sustained oscillations in the continuous emulsion polymerization of vinyl acetate is also discussed. How to control the instability and its bifurcation of transport phenomena with/without chemical reactions should be reconsidered taking into account the effect of hysteretic multiplicity in the states of flow and reaction for the purpose of introducing the methodology of emergent synthesis into a design concept of complex chemical processes and systems.
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TAKASHI NISHIMURA, YOSHIHARU MUKOUYAMA, SHUJI NAKANISHI, HIDEMITSU KON ...
1999 Volume 25 Issue 4 Pages
510-515
Published: July 10, 1999
Released on J-STAGE: November 12, 2009
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Two electrochemical oscillations, named oscillation A and B, are observed in H
2O
2 reduction reaction on Pt electrodes in aqueous acidic solutions. Oscillation A appears in potentials just before H
2 evolution, whereas oscillation B appears in the potential region of H
2 evolution. Both oscillations are caused by alternate occurrence of H
2O
2 reduction and suppression of the H
2O
2 reduction by adsorbed hydrogen (upd-H). It is found that synchronized current oscillations are induced by external potential pulses when they are positive and located in the low-current state of oscillation. This result can be explained to be due to removal of upd-H by the positive potential pulses which lead to positive shifts of the electrode potential. The relation between the duration of the low-current state and the peak current of the high-current state is investigated and the result supports our previously propose oscillation mechanism.
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MASAMI KAWAGUCHI, YOKO MAKINO, TADAYA KATO
1999 Volume 25 Issue 4 Pages
516-519
Published: July 10, 1999
Released on J-STAGE: November 12, 2009
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Characteristics of viscous fingering are investigated by pushing air in a radial Hele-Shaw cell, where hydroxypropyl methyl cellulose (HPMC) solutions are placed, as a function of temperature. High molecular weight HPMC sample was used since its solution leads to a strong shear thinning due to chain entanglements. The resulting patterns show a systematic change from side branching to skewering patterns through the tip-splitting patterns with an increase in the injection pressure, irrespective of temperature. The characteristic quantities of the pattern growth, such as finger velocity and finger width, are evaluated. Darcy's law modified by taking into account the effective viscosity at a shear rate imposed to HPMC solutions is compared with the measured finger velocity, and good agreement is obtained. The finger width shows a broad maximum where the tip-splitting patterns are observed.
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TETSUO AKIYAMA, YASUYO TSURUTA, KEIKO M. AOKI
1999 Volume 25 Issue 4 Pages
520-524
Published: July 10, 1999
Released on J-STAGE: November 12, 2009
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This paper describes the bistability of surface levels in vibrating particle beds. When a tube is vertically immersed in a particle bed, and the vessel containing the particles is subjected to vertical vibrations, the surface of the particle bed in the tube stabilizes at a level different from that outside the tube. The present study uses a two dimensional vessel. The vessel is partitioned into three sections, a central and two side sections, by the use of two vertical plates whose lower ends are set at 25 mm from the vessel base. Five sizes of glass beads (mean diameters in the range 116-1090 μm) were used. It is found that the bed surface sometimes stabilizes at two different levels when a series of experiments is conducted by changing the initial two surface levels, with other experimental conditions fixed. The causes of this bistability are discussed.
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NAOTAKE KATOH, TATSUO ISOI
1999 Volume 25 Issue 4 Pages
525-529
Published: July 10, 1999
Released on J-STAGE: November 12, 2009
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Empirical nucleation kinetics so called magma dependent power law model have been conventionally used for industrial crystallization.
However, this type of nucleation kinetics can not explain instability of industrial crystallizers.
In this paper, we reconsider nucleation kinetics as a function of first and second moments as well as magma density or third moment of population density. Cases of second and third moments show a possibility of multiple steady states.
Furthermore, using Hurwitz stability criterion we examine mechanisms of unstable steady state of crystallizers.
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TAKATOSHI YANO, RYUJI KIKUCHI, ATSUSHI TSUTSUMI, KUNIO YOSHIDA, MIROSL ...
1999 Volume 25 Issue 4 Pages
530-534
Published: July 10, 1999
Released on J-STAGE: November 12, 2009
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In the present study, nonlinear hydrodynamic behavior of bubbles and particles in a gas-liquid-solid three-phase reactor is characterized by deterministic chaos analysis in terms of correlation dimension. The embedding method is used to determine correlation dimension from the series of the time intervals between successive optical signals triggered by bubbles or particles. The axial and radial distributions of correlation dimensions are examined and the effect of superficial gas velocity on correlation dimensions for gas and solid phases is investigated.
In the bubbly flow regime, with increasing axial position the correlation dimensions for the gas phase increase to reach a maximum and slightly drop at the center of the column. On the other hand, in the churn-turbulent flow regime, the correlation dimension of the gas phase has a minimum at the middle of the column. The correlation dimensions of solid phase are 1-2 lower than those of gas phase, and decrease with axial positions. Uniform radial distributions of both gas and solid phases are observed except near the wall.
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SATOSHI NAKATA, KAORI TAKEMURA, TOMOKO HIRATANI, NOZOMI OJIMA
1999 Volume 25 Issue 4 Pages
535-538
Published: July 10, 1999
Released on J-STAGE: November 12, 2009
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Although gas sensors have been developed previously to achieve high selectivity for a particular chemical species, it is difficult to distinguish chemical species based on static information obtained with a single detector, such as the conductance of a semiconductor. This difficulty is due to the fact that gas sensors usually respond to interfering materials which coexist in a gas sample. In addition, a saturation effect at high concentration, competition among chemical species at the sensor surface, and the accumulation of an aging effect or hysteresis brought about by the use of the sensor for a long period. Recently, we described a new gas-sensing method with which we could quantitatively characterize the dynamic nonlinear responses of a semiconductor gas sensor by sinusoidally varying the power supply to the sensor heater and FFT analysis on the output response. In this paper, we report that the characteristic nonlinear responses to gas species, the saturation effect, and the competition between two gases on the sensor surface is quantitatively evaluated in relation to the kinetics of gas molecules at the sensor surface and the temperature-dependent surface barrier potential.
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NORIHIRO WATANABE
1999 Volume 25 Issue 4 Pages
539-542
Published: July 10, 1999
Released on J-STAGE: February 19, 2010
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In a refuse incinerator, relay feedback control is carried out to keep the vapor flow rate in the neighborhood of a constant value. Chaotic phenomena are observed in this control system. In this paper, a time series data of the vapor flow rate in a real plant is analyzed. The analytical results show that the correlation dimension is 1. 7 and the maximum Lyapunov exponent is 0.05. From these results, it is confirmed that oscillation of the vapor flow rate in the refuse combustion control system is chaotic.
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NOBUO MATSUDA, YUTAKA TADA, SETSURO HIRAOKA, YOSIRO MIZUTANI, KOJI KAM ...
1999 Volume 25 Issue 4 Pages
543-548
Published: July 10, 1999
Released on J-STAGE: November 12, 2009
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To clarify very low frequency fluctuations in the torque time series in an agitated vessel, the magnitude and periodicity of the fluctuations were examined from power spectrum analysis and autocorrelation function analysis of the measured torque time series in an agitated vessel with paddle impellers. The fluctuations consisted of quasi-periodic motions with three frequencies, blade passage frequency, rotation frequency, and another frequency (the third frequency), and a nonperiodic and very low frequency motion which was about 290 times long as that of the blade passage frequency. The fluctuation was fractal nature from fractal dimension analysis using the Higuchi method. The correlation dimension of the fluctuation had a non-integer value in the range 3.9-5.2 from correlation dimension analysis using the Grassberger-Procattia method. From these results, it is concluded that the very low frequency fluctuations in the torque time series in an agitated vessel can be described with a deterministic method.
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IZUMI HIRASAWA
1999 Volume 25 Issue 4 Pages
549-553
Published: July 10, 1999
Released on J-STAGE: November 12, 2009
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Crystal growth experiments were performed in a suspension system of sodium borate decahydrate crystals, to observe the surface status of crystals in the process of their growth, and to obtain the correlative equation of the factors (degree of supercooling, linear velocity in the crystallizer and revolution rate of the agitator) affecting secondary nucleation rate. It is also made clear that the average secondary nucleation rate based on the operation time is affected by the surface status of the growing crystals, and its rate osccillates against the operation time. This oscillation phenomena are discussed, based on the qualitative model of two series processes consisted of a diffuison stage and a surface reaction stage.
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JUNJI KAWAI, Q. IRAN CONG-MIYATA
1999 Volume 25 Issue 4 Pages
554-558
Published: July 10, 1999
Released on J-STAGE: November 12, 2009
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Morphology and phase separation kinetics of anthracene-labeled polystyrene/poly (vinyl methyl ether) (PSA/PVME) blends were investigated by means of phase-contrast optical microscopy combined with digital image analysis. A PSA/PVME mixture with an off-critical composition (40/60) was irradiated with ultraviolet light in the one-phase region to induce the photodimerization of anthracene moieties labeled on the PSA chain. It was found that the irradiated blend exhibits co-continuous morphology with multiple characteristic length scales. Furthermore, these modulated structures were frozen at an intermediate stage of phase separation due to the soft modes suppression of the reaction. These experimental results are in good agreement with the prediction by linear stabilty analysis of reaction-diffusion equations proposed for phase separating systems. The discretization of concentration fluctuations induced by photo-cross-linking reaction reveals promising methods using chemical reactions for morphology control of polymer blends.
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NAOTO OHMURA, KUNIO KATAOKA, SOICHI TSUKAMOTO, TATSUYA YANASE
1999 Volume 25 Issue 4 Pages
559-563
Published: July 10, 1999
Released on J-STAGE: November 12, 2009
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The effect of reactor volume on concentration oscillations in the cerium-catalyzed Belousov-Zhabotinsky reaction is observed by varying mean residence time of feed as a bifurcation parameter. Three CSTRs different in volume were used in the experiment with the same stirring conditions. Chemical oscillations are investigated by measuring the redox potential between Ce
3+ and Ce
4+ using a Pt-wire electrode. Owing to the effect of nonlinear coupling between essential chemical oscillations and external forcing oscillations by the peristaltic pump, chaotic oscillations occur in shorter mean residence time. It has been found that this coupling effect affects the greater concentration oscillations in smaller CSTR. At the bifurcation point between single-peak oscillation and chaotic oscillation state, intermittent oscillations are observed. It has been found that stable single-peak oscillations can be observed throughout wide mean-residence-time region with increasing volume of reactor.
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KENTARO OTAWARA, L. T. Fan
1999 Volume 25 Issue 4 Pages
564-568
Published: July 10, 1999
Released on J-STAGE: November 12, 2009
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Spontaneous oscillations in chemical reactions are often deemed inexpedient because of their propensity to cause operational complexities. Nevertheless, it has been demonstrated in our previous work that we can take advantage of such oscillations. For instance, it has been shown that the yield of the desired product from an autocatalytic reaction in a continuous stirred-tank reactor (CSTR) can be quadrupled with a pfoportional feedback mechanism. The results of additional case studies carried out in the current work indicate that for wide ranges of parameter values, the yield of the same reaction can be further increased and in some cases it can be around 50 times larger than the maximum value obtainable in the steady state operation.
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MASAYASU SUZUKI, TAKUJI MICHINAGA
1999 Volume 25 Issue 4 Pages
569-573
Published: July 10, 1999
Released on J-STAGE: November 12, 2009
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The availability of yeast glycolytic oscillator as a novel index of toxicity assay is investigated. Various chemical compounds were added to the glycolytic oscillator and the oscillation changes of NADH concentration were measured photometrically. The characteristic changes of wave patterns were observed by the additions of mercuric ion, fluoride, acetaraldehyde and so on, although respiratory inhibitors did not change the oscillation. Addition of a mixture of two chemicals causes additive or synergistic effects on the glycolytic oscillation. Further, the same oscillation can be observed even after 1 month by freeze-drying the prepared yeast extract. Although the number of chemicals which cause the characteristic oscillation changes is very limited, and the lower detection limit is not satisfactory, the possibility of a novel toxicity assay method can be shown.
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TETSUYA YAMAMOTO
1999 Volume 25 Issue 4 Pages
574-578
Published: July 10, 1999
Released on J-STAGE: November 12, 2009
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A method to differentiate taste compounds based on their electrochemical nonlinearity is proposed. We have quantitatively estimated the electrochemical nonlinearity of surfactant solutions by using the system-identification. Electrochemical nonlinearity is influenced by the addition of various chemical species such as NaCl, HCl, and Quinine-Hydrochloride. Electrochemical nonlinearity shows similar characteristics to the same category of taste and shows a concentration dependency. It is shown that the taste sensing system proposed in the present work is able to distinguish the kind of taste and to estimate quantitatively its concentration.
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RYO BABA, KIYOSHI INOKUMA, ANTONIS KARANTONIS, SEIICHIRO NAKABAYASHI
1999 Volume 25 Issue 4 Pages
579-584
Published: July 10, 1999
Released on J-STAGE: November 12, 2009
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Rayleigh-Bénard (RB) convection was observed in an electrolytic solution between two parallel copper wire electrodes. Electrochemically driven RB convection was achieved when the anode, where the electrodissolution of copper occurred, was placed above the cathode on which the reduction of ions took place. The motion of the solution was well controlled by the bias potential applied between the electrodes and the dissipation structure made by the flow of the fluid was visualized by using a laser interferometry. Under magnetic field normal to the plane of the convection the roll cells were found to travel horizontally along the wire electrode by the Lorentz force. It is shown that the electrochemically driven RB convection is controlled and monitored much simply than thermally induced conventional ones by adjusting electrochemical parameters and that the system has a wide variety in the structural regularity especially under magnetic field.
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TETSUO AKIYAMA, KEIKO M. AOKI, TAKEYUKI OISHI, TETSUO YOSHIKAWA
1999 Volume 25 Issue 4 Pages
585-587
Published: July 10, 1999
Released on J-STAGE: November 12, 2009
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When a vessel containing particles is subjected to vertical vibrations with an acceleration greater than 1 g, a convection mode of particles appears : particles move downward along the vertical side walls and upward in the middle, forming a heap. With the increase in vibrational intensity another convection mode sets in, wherein particles move upward along the vertical side walls and downward in the middle, forming a valley. The latter convection mode is stable enough to yield multiple pairs of convection rolls with a further increase in vibrational acceleration, showing strong nonlinearity of the system.
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TOSHIHIKO YOSHIDA, TAKAYUKI HOSHINA, HIDETO KOIDE, SHIN-ICHI WAKAYAMA
1999 Volume 25 Issue 4 Pages
588-594
Published: July 10, 1999
Released on J-STAGE: November 12, 2009
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A planar solid oxide fuel cell is investigated as an electrochemical tubular reactor with two dimensional reactive surface and a rectangular cross section. Analysis and experiments were carried out in order to clarify the prediction of electrical output, flow pattern and thermal generation.
The predicted resistance of cell materials and the measured polarization show that the electrical output is expected to be 4.5 × 10
3 W/m
2 of output density and 50% of electrical conversion efficiency using a hydrogen feed.
A feed gas is distributed to gas flow tubes through a gas manifold. Numerical analysis shows that each gas flow rate varies in the tubes when cell size in enlarged. The ratio of fuel partial pressure at outlet to that at inlet in a tube clearly decreases when Reynolds number in the tube increases to above 0.1 and fuel utilization to above 50%.
It is clarified that the electrical power generation heated up a planar solid oxide fuel cell and the heat distributed the temperature in the cell plane.
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KAZUO TSUTSUMI
1999 Volume 25 Issue 4 Pages
595-599
Published: July 10, 1999
Released on J-STAGE: November 12, 2009
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When using a fluidized bed for a limestone calciner, calcining reaction rate is decided by the process of CO
2 diffusion in quicklime produced outside of the CaCO
3 unreacted core in the crystal.
The CO
2 effective diffusion coefficient obtained by bench-scale testing has a relation to limestone' s crystal diameter. So CaCO
3 unreacted core model has been developed based upon CO
2 diffusion process. Calculated CO
2 effective diffusion coefficients decrease with increaseing temperature of fluidized bed and do not depend on species of limestone.
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TADAHIRO MURAKATA, YOSHIRO IKEKITA, [in Japanese], KOUKI YANAGI, NORIY ...
1999 Volume 25 Issue 4 Pages
600-607
Published: July 10, 1999
Released on J-STAGE: November 12, 2009
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Coals are degraded oxidatively as alkaline and acid coal-water slurries by indirect electrolysis using mediators. When Taiheiyou and Horonai coals are electrolyzed as alkaline coal-water slurries, about 80 % of the coals are degraded to humic acids which dissolve into the electrolyte. The humic acids in the electrolyte are further degraded to low molecular weight compounds through oxidation both by indirect electrolysis and by direct electrolysis on the anode. On the other hand, for acid coal-water slurries, the maximum conversions are only about 50% even after 50 h of prolonged electrolysis and the humic acids accumulated on the surface of coal particles. In the latter slurries, however, part of the coal is oxidized exhaustively to be converted to gas products such asCO
2. The electrolysis properties are studied further for the influence of coal rank and redox potential of the mediator. Mechanisms of the coal degradation in alkaline and acid slurries are discussed on the basis of the above experimental results
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SUSUMU TAKAHASHI, KOURYOU KOJIMA, SANKICHI TAKAHASHI
1999 Volume 25 Issue 4 Pages
608-612
Published: July 10, 1999
Released on J-STAGE: November 12, 2009
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The azeotrope which an aqueous 1, 4-dioxane solution shows at wide-ranged mixture mole fraction is supposed to result from the co-existence of water and 1, 4-dioxane in the solution. The present study investigates the state of both components of the solution and control of the liquid structure of water by 1, 4-dioxane and uses
17O-NMR chemical shift to perform a quantitative evaluation of the process by which hydrogen bonds are broken. The following conclusions are obtained :
1) The addition of 1, 4-dioxane, which is capable of breaking hydrogen bonds, can be used to effectively control the liquid structure of water.
2) The process by which hydrogen bonds are broken can be evaluated quantitatively using
17ONMR chemical shift.
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HIDEYUKI MATSUMOTO, CHIAKI KURODA, HIDEKAZU IRIE, KOHEI OGAWA
1999 Volume 25 Issue 4 Pages
613-618
Published: July 10, 1999
Released on J-STAGE: February 19, 2010
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In this study, the authors investigate a high performance liquid chromatography (HPLC) fractionation process which consists of many columns as a discrete event system, and apply a Petri net model to the HPLC fractionation process of plasma proteins. A quantitative model is constructed by considering both the order of operations and the separation behavior in the process. For example, in a semicontinuous injection model of the gel filtration chromatography fractionation process, the separation behavior is appropriately simulated using the flow of proteins, the flow of operations and inhibitor arcs which connect these two flows. A model of the ion exchange chromatography fractionation process is constructed considering that the time required for each operation is estimated from the operational conditions, i.e. the concentration of injected samples and the salt in an eluent.
Finally, the total simulation for an albumin monomer fractionation process is carried out using a combined Petri net model, which consists of some Petri nets based on the modes of separation and the styles of process. The results show that the Petri net model is useful for process design in modifying the number of HPLC columns, and the volume of intermediate tanks, because the dynamic behavior of the overall process is easily and clearly understood.
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SHIRO KONDO, KATSUTAKA NAKAMURA
1999 Volume 25 Issue 4 Pages
619-623
Published: July 10, 1999
Released on J-STAGE: May 07, 2010
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A theoretical analysis has been made to study the effect of electrophoresis and electro-osmosis on pressurized dewatering, although most research on pressurized electro-osmotic dewatering (PED) has focused on the effect of electro-osmosis. Through electrophoresis, negatively charged particles are attracted to the anode. The porosity of the cake formed on the filter cloth on the cathode side increases. As a results, filtration speed increases. The analysis includes two drainage methodes, unilateral and bilateral drainage. The theoretical values agree well with the values obtained from the experiment applying sludge generated from a water purification plant to a small horizontal column.
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GUILIN PIAO, SHIGERU AONO, MOTOHIRO KONDOH, MASATAKA YAMAGUCHI, RYOHEI ...
1999 Volume 25 Issue 4 Pages
624-628
Published: July 10, 1999
Released on J-STAGE: November 12, 2009
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Power generation from Refuse Derived Fuel (RDF) is a promising utilization technology for municipal solid waste.
To explain the combustion behaviors of RDF burnt in a fluidized bed incinerator, the commercial sized RDF was fed continuously in to a 0.3 ×0.3 m× 2. 73 m in height bubbling-type fluidized bed combustor and CO, NO
x, SO
x and HCI concentrations in the flue gas from the combustor were detected by a continuos measurement system. It is found that CO concentration in the flue gas is greatly increased by increasing the RDF feed rate, and CO concentration in the flue gas is greatly decreased by increasing the air ratio because the volatile matters rate is extremely great in combustion of RDF. It is also significantly affected by the secondary air injection and the air distribution ratio from the distributor. HCI concentration in the flue gas is effectively controlled by the calcium compound contained in RDF. HCI concentration is-maintained to be less than 60 ppm when the bed temperature is 800°C, and the HCI removal ratio by the calcium component is higher than 70% even though under the higher bed temperature than 900°C. NOx concentration was among 5050 ppm and SO
x concentration is less than 0.5 ppm.
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EIJI NAKAJIMA, TAKESHI YAMANE, MASAMICHI YOSHIDA, HISASHI MIYASHITA
1999 Volume 25 Issue 4 Pages
629-634
Published: July 10, 1999
Released on J-STAGE: November 12, 2009
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Bénard convection in a water layer heated from below is studied numerically for cases with and without density inversion. Calculations were carried out for varying the temperature difference between the top and bottom walls. Moreover, for the case where density inverses, the aspect ratio was also incorporated into parameters. When density inversion occurs, the number of cells takes a maximum value at the commencement of the convection, which equals double the inverse of the aspect ratio, and exhibits a tendency to decrease as the Rayleigh number increases. The Nusselt number for the case with density inversion is smaller than that for no density inversion because a stagnant region forms at the top of the cavity behaves as a thermal resistance. However, the difference in the Nusselt number decreases as the Rayleigh number increases. Further, an approximate model is proposed to predict the heat transfer rate and the critical Rayleigh number for the case with the density-inverting system. The predicted critical Rayleigh number shows good agreement with numerical one.
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ZHONG BING DONG, KENJI HASHIMOTO, ATSUSHI SATO, MASARU OKADA, YOSHIHIK ...
1999 Volume 25 Issue 4 Pages
635-641
Published: July 10, 1999
Released on J-STAGE: November 12, 2009
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Continuous experiments on sulfurization and oxidation of CaO particles were carried out in a thermobalance with a quartz spring. The effects of temperature, O
2 partial pressure, initial CaS content and particle diameter on oxidation reaction of CaS particles are investigated under advanced pressurized fluidized bed combustion conditions. Our experimental results show that the CaS particles with initial CaS content of 30 mol% and diameter below 0.9 mm are completely oxidized in atmospheres with 0
2 partial pressures of 1.01 kPa and 5.07 kPa at temperatures of 1, 203 and 1, 253 K. For 0.2 and 0.5 mm particles with initial CaS content of 80 mol%, the complete conversion is achieved at 1, 253 K in atmospheres with O
2 partial pressures of 1.01 to 21.3 kPa. It is found that CaS particles are first oxidized to form CaO through the reaction (1) : 2 CaS + 3 O
2→2 CaO + 2 SO
2 ; and then the releasing SO
2 gas through CaO layer reacts with the diffusing O
2 to form CaSO
4 product layer through the reaction (2) : 2CaO + 2 SO
2 + O
2→2 CaSO
4. Due to the higher molar volume of CaSO
4 than those of CaS and CaO, the diffusing rates of SO
2 and O
2 gases passing through the CaSO
4 layer become slower, consequently the oxidation reaction declines and finally ceases. A kinetic study on the initial reaction rate shows that reactions (1) and (2) are both the first order with respect to oxygen and have activation energies of 426 kJ/mol and 52 kJ/mol, respectively.
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MASAFUMI KURIYAMA, HIDEKI TOKANAI, HIROTAKA KONNO
1999 Volume 25 Issue 4 Pages
642-647
Published: July 10, 1999
Released on J-STAGE: November 12, 2009
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A population balance equation is solved numerically to obtain the transient size distributions of high-viscosity drops dispersed in agitated vessels. Three parameters included in the equation, such as breakup frequency, daughter drop distribution and the number of daughter drops formed per breakup of a parent drop, are proposed based on the author's previous studies for high-viscosity drops (Kuriyama
et al., 1995 a, 1995 b, 1996) and the previously proposed model for the breakup oflow-viscosity drops (Konno
et al., 1983).
Measurements of transient drop-size distribution were made under various operating conditions. Through comparison of calculated distributions with experimental ones, the drop-breakup model proposed in this work is found to be capable of predicting the transient drop-size distributions over a wide range of drop viscosities.
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YOSHIHIRO MURAKAMI, KEN'ICHI ISHIKURA, HIRONOBU UCHIYAMA, SATOSHI TANI ...
1999 Volume 25 Issue 4 Pages
648-654
Published: July 10, 1999
Released on J-STAGE: November 12, 2009
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For a process with parallel production lines, a scheduling algorithm possessing the function of allocating each job to a desirable production line is proposed. The proposed algorithm is based on the repetitive simulated annealing (SA) method, in which the scheduling is executed several times for a problem, and the best schedule is selected in the final stage of repetition. In the proposed algorithm, the feature of the repetitive SA method described above is successfully incorporated. First, desirable production lines for treating each job are derived from the scheduling results obtained through several rounds of scheduling. Then, scheduling of the remaining rounds is executed under the condition that the probabilities of allocating a job to desirable production lines are higher than those to the other lines. The proposed algorithm is applied to the scheduling problem of a heat treatment process consisting of nine production lines. The effectiveness of the proposed algorithm is demonstrated through a comparison between scheduling results obtained with the proposed method and those obtained with the conventional repetitive SA method.
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Formulation of Numerical Results and Comparison with Experimental Results
OSAMU MIYATAKE, KOTARO TAGAWA, HIDEHIKO NODA
1999 Volume 25 Issue 4 Pages
655-661
Published: July 10, 1999
Released on J-STAGE: February 19, 2010
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Based on the authors' previous numerical results of a reverse osmosis desalinationsystem for seawater or brackish water utilizing the static pressure head of seawater in a deep-sea region or brackish water in a vertical pit, a dimensionless expression is formulated to predict the transmitted fresh water flow rate from the geometry and the submerged depth of the device, the pure water permeability and the solute permeability of membrane, and the physical properties of seawater or brackish water.
The derived expression is compared with experimental results obtained by field experiments carried out in the Sea of Japan and the East China Sea with fair agreement and thus confirmed the applicability and usefulness of the expression.
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TAKANOBU ASAKAWA, KATSUTOSHI INOUE, KAZUHARU YOSHIZUKA, KEISUKE OHTO
1999 Volume 25 Issue 4 Pages
662-664
Published: July 10, 1999
Released on J-STAGE: November 12, 2009
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Solvent extraction of silver using 5, 5-Diphenyl-2, 4-Imidazolidinedione as an extractant is investigated. It is found that the distribution ratio was second order dependent on both of extractant and silver (I) ion concentration as well as inversely dependent on hydrogen ion, suggesting that silver (I) ion is extracted as binuclear complex, Ag
2R
2. The extraction equilibrium constant
K is evaluated as 2.0 × 10
-5 [dm
3/mol]. Stripping of loaded silver is nearly completely accomplished by 0.1 mol/dm
3-nitric acid. Silver was selectively extracted over thallium (I), nickel (II), copper (II), and even over palladium (II).
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ITARU KATO, SHIGETAKA KAI, TOMOYO MITANI, SATORU KATO, KUNIO NAGAHAMA
1999 Volume 25 Issue 4 Pages
665-667
Published: July 10, 1999
Released on J-STAGE: November 12, 2009
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The effects of presence of NO
2 or water vapor on the enhancement of the amount of adsorption of NO are investigated using a fixed bed of hydrogen-type synthetic mordenite at 303 K.
The amount of NO adsorbed increases with increasing concentration of NO
2 in the mixed gas including 400 ppm NO, and it also increases with increasing concentration of NO in the mixed gas including 300 ppm NO
2 : the presence of NO
2 enhances the amount of NO adsorbed on the hydrogenated synthetic mordenite. Meanwhile, the presence of water vapor causes a decrease in the amount of NO adsorbed.
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PHAN DO HUNG, TERUYUKI MASAWAKI, SETSUJI TONE
1999 Volume 25 Issue 4 Pages
668-671
Published: July 10, 1999
Released on J-STAGE: November 12, 2009
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Composite membranes composed of an acrylic acid-acrylonitrile copolymer layer crosslinked by ethylene glycol diglycidyl ether and a porous alumina support were prepared and evaluated for the pervaporation separation of methanol (MeOH) from MeOH/methyl t-butyl ether (MTBE) mixtures. The permeation fluxes of both components decreases and separation factor increases with increasing crosslinking agent content. Moreover, the permeation rate is expressed by the solution-diffusion model, considering the swelling effect of methanol component, and the effect of temperature on the permeation fluxes and the separation factor is estimated by using the apparent activation energy values.
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TAKAYUKI WATANABE, HARUO KAWASAKI
1999 Volume 25 Issue 4 Pages
672-675
Published: July 10, 1999
Released on J-STAGE: November 12, 2009
JOURNAL
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The paraldehyde chemical heat pump generates cold thermal energy with depolymerization of paraldehyde (2, 4, 6-trimethyl-trioxane). This study investigates the by-products in the heat pump system. Crotonaldehyde (2-butenal) and the polymer of crotonaldehyde are main by-products. The proposed heat pump system has the solution cycle for the by-product. The cooling rate and the coefficient of performance of the proposed system decreases with a decrease in the amount of cyclic solution.
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