KAGAKU KOGAKU RONBUNSHU
Online ISSN : 1349-9203
Print ISSN : 0386-216X
ISSN-L : 0386-216X
Volume 24 , Issue 4
Showing 1-35 articles out of 35 articles from the selected issue
  • HITOSHI HABUKA
    1998 Volume 24 Issue 4 Pages 527-537
    Published: July 10, 1998
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Transport phenomena and chemical reactions relating to silicon epitaxial thin film growth at 1073-1398 K in a SiHCl3-H2 system with dopant gas of B2H6 under atmospheric pressure are studied theoretically and experimentally for a cold-wall horizontal single-wafer reactor. The effects of substrate rotation and thermal diffusion on SiHCl3 gas and B2H6 gas are discussed. The nonlinear increase in silicon epitaxial growth rate with SiHCl3 concentration at the inlet of the reactor is discussed by investigating changes in the transport of the chemical species to the substrate surface, and the saturationof chemisorbed species at the surface. Indicators for the rate limiting factor for species transport and reaction are discussed to investigate the saturation of the epitaxial growth rate, and are shown to be effective for quantitatively describing the rate limiting process. Various phenomena to be modeled in epitaxy are also addressed.
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  • KAZUHIRO TAKEDA, KEN-ICHI YUNOKI, YOSHIFUMI TSUGE, HISAYOSHI MATSUYAMA
    1998 Volume 24 Issue 4 Pages 538-545
    Published: July 10, 1998
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Eguipment repair, eguipment failure, inferior goods, and urgent orders are major obstacles for scheduled production, and contribute to low productivity and long lead-time in manufacturing plants with incomplete production technology.
    This paper presents a decentralized scheduling algorithm under the assumption that proper preventive repairs can decrease the occurrence of equipment failure and inferior goods. This algorithm can realize high productivity and short lead-time and be hardly affected by frequent equipment repair. The effectiveness of this algorithm is demonstrated by simulations of a plant model based on real plant manufacturing application specified integrated circuits.
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  • TOMIO MIMURA, SHICHIRO SATUMI
    1998 Volume 24 Issue 4 Pages 546-551
    Published: July 10, 1998
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A process for recovering CO2 from the boiler flue gas of a power plant by a chemical absorption method requires a large amount of steam to regenerate the spent absorbent.
    The recovery heat exhausted from the CO2 recovery process and utilization of the recovered heat as a sourse of power plant feed water heating is studied. The reduction of generated power, required for the CO2 recovery from the flue gas by the chemical absorption method is evaluated.
    The effectiveness of such a heat recovery process is assessed in terms of the power loss. The power loss by heat recovery is decreased to one-third compared with that in the case of no heat recovery.
    The reduction of power generated in a natural gas-fired power plant is evaluated to be about 56 % when new absorbents KS-1 and KS-2 are used in the CO2 recovery process. In the case of a coal-fired power plant, the power loss amounts to about 9%.
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  • HAJIME SUGITA, YOSHIYUKI BANDO, MASAAKI NAKAMURA
    1998 Volume 24 Issue 4 Pages 552-557
    Published: July 10, 1998
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    For the seeding method by using silica gel, the effects of pH and operational conditions on the silica removal performance are experimentally investigated. The silica removal ratio is estimated by the quasi-stable concentration of silica measured under various conditions.
    The initial pH was changed in the range of 5-9. When the initial silica concentration is 0.5 kg-SiO2·m-3, the silica removal ratio increases with increasing initial pH. The silica removal ratio has a maximum and a minimum when the initial silica concentration is 0.7 kg-SiO2·m-3, and has a minimum when the initial silica concentration is 0.9 kg-SiO2·m-3. When the initial pH is the same, the silica removal ratio increases with increasing temperature and with decreasing initial silica concentration. While the silica removal ratio is not affected by the pre-seeding time in the case of lower initial silica concentrations, it increases with decreasing pre-seeding time in the case of higher initial silica concentrations. The seeding method is considered to be applicable to treat the present geothermal brine.
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  • TAKEHIKO KUMAGAI, SHOICHI KONDA, TAKESHI SASAKI, TATSUO ISHIKAWA, TADA ...
    1998 Volume 24 Issue 4 Pages 558-561
    Published: July 10, 1998
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Reaction characteristics were examined for synthesis of K2TiCl6 from KCl particles and TiCl4 gas. The reaction experiments were carried out exposing different sizes of KCl particles to a TiCl4 gas stream at 683 K. The mass gain due to formation of K2TiCl6 was measured as a function of time and morphology of the product was observed by SEM and EPMA. The apparent reaction rate decreases rapidly with the progress of the reaction, and the reaction is virtually terminated before its completion EPMA analysis on the particle cross-section reveals that the products are distributed around an unreacted KCl core within the particle, and the termination of the reaction takes place when the thickness of the outer product layer grows up to about 6 μm. The reaction kinetics are explained well on the basis of an unreacted-core model which assumes that the rate determining step is the intra-particle TiCl4 gas diffusion.
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  • YUICHI OHIRA, EIJI OBATA, YOSHIKAZU KUGA, KOJI ANDO
    1998 Volume 24 Issue 4 Pages 562-567
    Published: July 10, 1998
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Effects of light intensity and irradiation time on respiration rate in the dark period after irradiating are discussed. The specific respiration rate of S. platensis in the dark is a constant value Q1, up to 15-30 minutes, and then rapidly decreases to Q2 after 30 minutes. The specific respiration rate Q1 increases with light intensity. No significant effect of Q1 on irradiation time and Q2 on light intensity is observed. The respiration rate for a long dark time, Q0 (= 1.2 mg-O2·kg-Spirulinct-1·s-1), is almost the same as Q2. The effect of the logarithmic mean light intensity I1m [k1x] on Q1 is described by the following equation.
    Q1-Q0=13I1m/15+I1m
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  • YUKITSUGU SHOJI, KYOZO SATO, D. R. OLIVER
    1998 Volume 24 Issue 4 Pages 568-572
    Published: July 10, 1998
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Experiments were performed to study heat transfer enhancement in a round tube using wire coils as turbulators. The present study investigates the effect of the clearance between the inner wall of the tube and the wire coil (ε/Di = 0.007, 0.05, 0.15, 0.21 and 0.30). The wire coils were made from 1.50 mm diameter copper wire. The test fluid was water. Both heat transfer and pressure drop are measured, and were compared with data for empty tube case.
    As a result, the heat transfer and the pressure drop decrease with the increasing clearance. A heat transfer correlation is given as NuH = {0.231-0.456 (ε/Di)} · ReH0.64· Pr13.
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  • YUKITSUGU SHOJI, KYOZO SATO, D. R. OLIVER
    1998 Volume 24 Issue 4 Pages 573-577
    Published: July 10, 1998
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Experiments were performed to study the heat transfer enhancement in a round tube using wire coils as turbulators. The present study investigates the effects of length and segmentation of the wire coil. Experiments were conducted for three different wire coils (1, 000, 500, and 300 mm) on the effect of length. The wire coils used to measure the effect of segmentation were three different types, and, total lengths of these wire coils were all the same (500 mm × 1, 100 mm × 5, and 50 mm × 10). The wire coils were made from 1.5 mm diameter copper wire. The test fluid was water. Both heat transfer and friction factor were measured, and are compared with each other.
    As a result, the heat transfer and the friction factor decrease with increasing clearance. The heat transfer correlations are given as Eq. (7) in the case of the effect of the length, and Eq. (10) in the case of the segmentation.
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  • YOSHIHIRO MURAKAMI, MIKIYA OKADA, HIRONOBU UCHIYAMA, SHINJI HASEBE, IO ...
    1998 Volume 24 Issue 4 Pages 578-584
    Published: July 10, 1998
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    In chemical batch processes, the feasibility of the production sequence of jobs on successive units depends on the number of storage tanks between the units. When some jobs take different production paths between two batch units, it is more difficult to judge whether the production sequence of jobs is feasible or not. In this paper, for the process which has a complicated flow structure and many storage tanks, the condition that the feasible production sequence must satisfy is derived. Then, using the derived condition, a scheduling algorithm based on the simulated annealing method is improved so that the algorithm searches only the feasible production sequences. The improved algorithm has been applied to a practical large scheduling problem, and it has become clearer that plausible schedules can be generated with a shorter computing time.
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  • TOSHIYUKI NOMURA, YOSHIYUKI YAMADA, HIROAKI MASUDA
    1998 Volume 24 Issue 4 Pages 585-590
    Published: July 10, 1998
    Released: February 19, 2010
    JOURNALS FREE ACCESS
    The tribo-charging characteristics of powder in a rotating vessel are investigated under different humidities to clarify the effect of charge relaxation of powder. The sample powder was prepared through coating of ferrite carrier particles with silicone resin.
    It is found that the absolute value of the maximum charge of powder decreases sharply with increasing relative humidity below 30%, while the change is relatively small above 30%. The contact potential difference against a reference electrode is dependent on the relative humidity both for the powder and the wall material of the vessel, while the contact potential difference between the powder and the wall material is found to be constant, even if the humidity is varied. The maximum charge of powder is predicted well by using the conventional time constant that is obtained as the product of dielectric constant by the resistivity of the powder. However, the tendency of the charging characteristic curve can not be predicted as far as the conventional time constant is used. On the other hand, the charging characteristic curve can be predicted well using the time constant obtained by the null current potential curve in the measurement of contact potential difference.
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  • MASASHI KURAMAE
    1998 Volume 24 Issue 4 Pages 591-596
    Published: July 10, 1998
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The gravity inclination method, which has been utilized for measuring the heat transport capability of a heat pipe, is applied to estimate the reflux force of the Marangoni effect caused by concentration difference in a two-component heat pipe in a gravitational field. It is shown that the Marangoni force become larger for heat pipes containing water-ethanol or water-acetone solution of relatively dilute concentration, as expected by previous microgravity experiments. Experimental results ofheat pipes containing water-acetone mixture, which were different from those of water-ethenol mixture, do not agree well with the results predicted by the method as designated in the previous paper. However, these are explained by considering the difference of NTU (number of transfer unit) of each two-component mixture.
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  • KANAKO TANAKA, CHING-JU WEN, AKIHIRO YAMAZAKI, KOICHI YAMADA
    1998 Volume 24 Issue 4 Pages 597-602
    Published: July 10, 1998
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A solid oxide fuel cell (SOFC), its module and 1 MW system using CH4 fuel are designed. The performance data of the SOFC system is calculated over a wide range of working temperatures and steam to carbon ratios (S/C). For the calculation, over-potential and electrolyte resistance values at a lower temperature than 1000°C are assumed to be as the same as those actually obtained at 1000°C. The SOFC system was evaluated using measures of cost and energy payback times (CPT, EPT), The calculation results using thermodynamic data showed that the generation efficiency of SOFC increased with the decrease of the working temperature. A lower temperature operation of SOFC shortened the CPT and EPT, because it enabled the application of lower cost materials, the size-reduction of equipment and the improvement of unit fuel consumption for the SOFC system. The lowering of S/C was also important to decrease the CPT and EPT. The evaluation results indicated that operating conditions of S/C =1.0 1.5 and the working temperature lower than 800°C were target values to realize the SOFC system.
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  • HAJIME HORI, YOSHINARI TAGUCHI, MASATO TANAKA
    1998 Volume 24 Issue 4 Pages 603-608
    Published: July 10, 1998
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Composite particles composed of waste polymer and waste paper fibers were prepared by a chemical crushing method.
    Newspaper was used as paper fiber. Polystyrene beads, which were prepared by suspension polymerization, were adopted as the waste polymer. In the experiment, in order to adjust the affinity for the polymer solution, paper fibers were pretreated using a few treatment agents.
    It is found that the mechanical strength of the composite particles increases by addition of fibers. Furthermore, it is found that there is an optimum concentration for each treatment agent.
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  • ATSUSHI SHONO, YASUHIKO KIKUCHI, ISAMU KUBOTA, KAZUMI SATO
    1998 Volume 24 Issue 4 Pages 609-614
    Published: July 10, 1998
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Sodium extraction and water uptake from a sodium chloride aqueous solution by a di (2-ethylhexyl) phosphoric acid (D 2 EHPA) /n-heptane system was experimentally studied.
    The behavior of water uptake was classified into three regions based on the pH dependence of the water content, W0. In the region of pH 1-4 (Region 1), the molar ratio of sodium in the organic phase to total D 2 EHPA, ENa, increased when pH was higher. However, W0 was low and did not depend on pH. In the pH region over 6 (Region 3), W0 was high and showed no pH dependence. D 2 EHPA existed as sodium di (2-ethylhexyl) phosphate (SD 2 EHP) and formed reversed micelles in this region.
    In the region of pH 4-6, both ENa and W0 increased with the rise in pH. This region is thought to be a transition state from D 2 EHPA-Na complex to the formation of the reversed micelles.
    The behavior of the water uptake into the organic phase at the Region 1 and 2 was analyzed by the extraction equilibrium theory. It was found that the pH dependence of the water content under the low loading ratio could be explained using the model that water molecules coordinated into D 2 EHPA-Na complexes.
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  • TAKASHI HAMAGUCHI, HIDETO MIURA, AKIHIKO YONEYA, YOSHIHIRO HASHIMOTO, ...
    1998 Volume 24 Issue 4 Pages 615-619
    Published: July 10, 1998
    Released: February 19, 2010
    JOURNALS FREE ACCESS
    In this paper, an algorithm is proposed for on-line real-time diagnosis of faults that cannot be diagnosed by conventional algorithms. Pulse-type failures or failures involving oscillating statevariables, for example, can be diagnosed, and with far less memory than by a multistage algorithm in which the number of stages increases with fault proliferation. Through the use of a cause-effect matrix, possible fault proliferation paths can be rapidly calculated by a Boolean.
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  • TADAO NIWA, MIHO KATAOKA, HIROKAZU NISHITANI
    1998 Volume 24 Issue 4 Pages 620-627
    Published: July 10, 1998
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A pipeless batch plant is a batch processing production system using mobile vessels. The plant performances depend on both hardware of equipment and software of operation. So the plant includes many design factors such as number of vessels, stations and AGVs, layout of stations, vessel moving rules, job scheduling and so on.
    In this paper, the characteristics of pipeless batch plant design are considered to handle the problem by the systems engineering approach. Then, a practical design method known as design-by-analysis is applied to solve such a complex design problem. Based on this concept, a design support system composed of modeling, simulation and evaluation subsystems is developed. This system enables rational decision making through performance evaluation for proposed design of a pipeless batch plant. The usefulness of the system is illustrated by industrial examples.
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  • DAISUKE TANEDA, TAICHIRO MASAGAKI, KUNIO KATO
    1998 Volume 24 Issue 4 Pages 628-632
    Published: July 10, 1998
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The relationship between mean residence time of fine particles and operating conditions in a Powder-Particle Fluidized Bed was studied using silica sand (dp= 550 μm) as coarse particles and, Al(OH)3 (dp=1.4-15 μm) and Al2O3 (dp= 3 μm) as fine particles. Fine particles were fed continuously to the bed and data were obtained under steady state. The mean residence time of fine particles increased with a decrease in gas velocity and fine particle size. When the relative humidity of the fluidization gas was 75 %, the mean residence time of fine particles (Al(OH3), dp = 3 μm) was 3000 times as large as that of thefluidization gas. The effect of relative humidity depended strongly on the characteristics of charge with static electricity and wetting properties of the fine particles. There was a big difference in the mean residence time of each particle size when particle size distribution was wide. When the uniformity of the mean residence time of each particle size is needed, an adjustment of particle size distribution is required.
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  • YOSHINARI TAGUCHI, MASATO TANAKA
    1998 Volume 24 Issue 4 Pages 633-637
    Published: July 10, 1998
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Suspension polymerization was performed using Tricalcium Phosphate (TCP) as a stabilizer. The zeta potential of TCP in the continuous water phase varied with surfactants adsorbed on TCP, and by changing surfactants, the effect on the polymer particle size was investigated.
    At about 0 mV zeta potential of TCP, it coagulated, but the adhesion amount of TCP on the droplet surface increased. Consequently, polymer beads with smaller size and higher uniformity were prepared.
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  • ATSUSHI IKARI, YASUO HATATE, RYOKO AIKO
    1998 Volume 24 Issue 4 Pages 638-641
    Published: July 10, 1998
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Pillow-type packings were prepared by wrapping ion exchange resin with stainless steel wire netting. An experimental apparatus for batch distillation was constructed, in which 60 packings were packed.
    Aqueous ethanol solutions containing a minute amount of ethyl acetate were chaged in the still and distilled. When all the condensed top vapor was returned to the column, the concentration of ethyl acetate in distillate decreased rapidly, and the concentration of acetic acid in the still increased gradually.
    On the contrary, when the aqueous ethanol solution containing a minute amount of acetic acid was distilled, ethyl acetate was produced in the column, and its concentration in distillate increased gradually.
    From these experimental results, the applicability of catalytic distillation for removing a minute amount of ethyl acetate in aqueous ethanol solution is discussed.
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  • TOSHIYUKI NOMURA, YASUO KOUSAKA, KEN TANAKA
    1998 Volume 24 Issue 4 Pages 642-645
    Published: July 10, 1998
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The engineering model, where the number concentration of particles generated by homogeneousnucleation n* is determined so that the generation rate of monomers G* is equal to their vanishing rate at monomer concentration C*, which corresponds to a critical supersaturated state of nucleation, has been proposed by the present authors (Kousaka and Nomura, Kagaku Kogaku Ronbunsyu, 23, 666-672 (1997)). The cell model, which is familiar in particle dispersed systems, is applied and the solution of unsteady diffusion rate of monomers onto a nucleus is used in the analysis. As a result, we obtain the relation among the parameters as G* =4πr* DC* n*, where D is diffusion coefficient of monomer, and r* is radius of nucleus. The effect of monomer diffusion coefficient on particle generation, which is one of the factors included in the engineering model, is studied for systems where silver particles are generated by a reduction method in the liquid phase. The monomer diffusion coefficient is controlled by changing viscosity of the solution by addition of a thickener, and it is found experimentally that the number concentration of particles generated is inversely proportional to the monomer diffusion coefficient resulting in particle size reduction, which quantitatively support the model.
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  • TAMIO NODA, MOTOYUKI SUZUKI
    1998 Volume 24 Issue 4 Pages 646-652
    Published: July 10, 1998
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The adsorption of acetaldehyde by porous ceramics impregnated with hydrazinium aluminum sulfate (HAS) is studied. Silicagel, activated alumina, activated clay, and activated carbon are compared, and it is found that silicagel and activated clay are suitable as a substrate for HAS impregnated adsorbent. The adsorption mechanism of acetaldehyde by the adsorvent is believed to be one in which acetaldehyde reacts with hydrazinium and yields acetaldazine. The adsorption capacity of the adsorvent at low acetaldehyde concentration of 0.1 ppm was as large as 1.36 mol/kg. This adsorption capacity at 0.1 ppm acetaldehyde concentration is remarkably larger than that of conventional activated carbon. Hydrazinium decomposes easily in the air because it is a strong reducing agent and reacts with oxygen or carbon dioxide. But hydrazinium impregnated on porous ceramics with HAS becomes more stable and maintains reactivity with acetaldehyde for longer than six months. An adsorbent made of porous ceramics impregnated with HAS is useful as a deodorant for acetaldehyde.
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  • KAZUO IDEI, YASUO YAMAMOTO, SADAO TAKEHARA
    1998 Volume 24 Issue 4 Pages 653-659
    Published: July 10, 1998
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    In this paper, each deactivation of catalyst for start, middle, and end of run in the hydrodesulfurization (HDS) process is theoretically interpreted as the behavior due to the reduction of active sites and effective diffusivity that is caused by coking and deposition of metal (Ni, V). In the previous report, catalyst deactivation in HDS was viewed as a model of simple simultaneous equations assuming that deactivation was the sum of first -order reduction rate of different active sites.
    In this study, furthermore, based on a long-term test using Arabian heavy atmospheric residue, a deactivation model due to diffusivity within the catalyst pores is made, and an overall deactivation equation interpreting the all behaviors of deactivation through a HDS run is developed by adding the diffusion model to the previous active site model. In this report, the concept of the new kinetic model and method to determine the deactivation parameters that compose the overall deactivation equation are described, and also various catalyst deactivations in HDS of light and heavy oils are analyzed by the new equation.The analytical results agree with all deactivation behaviors. Furthermore, the deactivation parameter obtained by analysis are discussed with the physical properties of the catalysts, and the applicability of the overall deactivation equation is also referred.
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  • MITSUMASA KIMATA, HITOSHI KASHIWAYA, MASAHIRO HASEGAWA
    1998 Volume 24 Issue 4 Pages 660-664
    Published: July 10, 1998
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Monodispersed electroconductive particles were prepared by nitriding composite particles. The composite particles were monodispersed silica particles coated uniformly with a titania layer. The composite was obtained by hydrolysis of titanium isopropoxide in the presence of silica seed particles synthesized by hydrolysis of tetraethyl orthosilicate. The nitriding experiments of composite particles were conducted in a tube furnace at various temperatures and constant flow rate of ammonia gas. X-ray diffraction patterns of the composite particles after nitriding revealed that titanium nitride was produced at temperature higher than 973 K. From scanning electron micrographs, it was found that composite particles after nitriding are maintained as monodispersed forms of seed particles. The electroconductivity of the composite particles after nitriding is high enough for practical usage.
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  • KEN-ICHIRO SOTOWA, KIYOSHI NAITO, MANABU KANO, SHINJI HASEBE, IORI HAS ...
    1998 Volume 24 Issue 4 Pages 665-669
    Published: July 10, 1998
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The method of characteristics is a numerical algorithm which is well suited to the simulation of first-order, partial differential equations. In this study, the method of characteristics is extended to enablethe simulation of crystallization processes even when the crystal growth rate varies with crystal size. A finite difference scheme and the method of characteristics are compared in terms of simulation results of a crystallization process. When the method of characteristics is employed, the numerical result is not affected by the mesh size, whereas the numerical solution obtained by applying a finite difference scheme shows strong mesh dependency. Since the numerical results obtained using the finite difference scheme are significantly different from those obtained using the method of characteristics, it is shown that the finite difference solution is strongly influenced by the numerical dispersion.
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  • KAYOKO MORISHITA, TAKAYUKI TAKARADA
    1998 Volume 24 Issue 4 Pages 670-674
    Published: July 10, 1998
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    In order to efficiently recover carbon nanotubes, the purification method by wet oxidation with orthoperiodic acid and perchloric acid is investigated. The reactivity of the carbonaceous material toward the acids depends on the type of carbon. Carbon nanotubes are selectively recovered under the mild oxidation conditions. The degree of purification depends on the concentration of orthoperiodic acid. It is suggested that wet oxidation is an effective method for purification of carbon nanotubes.
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  • MIKIKO FUKUSHIMA, NAOTAKE KATOH
    1998 Volume 24 Issue 4 Pages 675-677
    Published: July 10, 1998
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Zone melting process usually limited to separation in the solid phase was examined to purify frozen aqueous solution by using a new zone melting technique developed by authors. This new process without movement of either sample tube or heaters enabled us to realize zone melting operation to the frozen aqueous solution.
    Experiments of cobalt concentration in the aqueous phase showed 40% reduction of initial concentration with one zone path number. Therefore, more reduction of impurity concentration can be expected by increasing zone path number.
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  • ATSUSHI IKARI, YASUO HATATE, RYOKO AIKO
    1998 Volume 24 Issue 4 Pages 678-681
    Published: July 10, 1998
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Vapor-liquid equilibria of aqueous ethanol solutions containing a minute amount of acetaldehyde, isobutyraldehyde, ethyl acetate and isoamyl acetate were measured by use of an Othmer-type still at 12.7, 25.3 and 101.3 kPa.
    The equilibrium ratio curves of the minor components (isobutyraldehyde, ethyl acetate and isoamyl acetate) at each pressure are presented by a function of the concentration of ethanol.
    However, the equilibrium ratio curves of the minor component (acetaldehyde) could not be obtained, because the data is slightly scatted.
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  • KENJI UKAI, JUNICHI NAKAYAMA, KEN TOYOKURA
    1998 Volume 24 Issue 4 Pages 682-685
    Published: July 10, 1998
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Precipitation of calcite is studied by reaction between aqueous solutions of calcium chloride and sodium carbonate in a batch crystallizer. Calcium carbonate intermediate generated by the reaction between these solutions is transformed to calcite quickly by addition of sodium chloride crystals, and the shape and the range of crystal size distribution of precipitated calcite is affected by the addition time of sodium chloride crystal. The operational temperature which calcite precipitated dominantly is determined in the range of 293 K to 328 K.
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  • YOSHITOMO HANAKUMA, JUNZOU YAMAMOTO, EIJI NAKANISHI
    1998 Volume 24 Issue 4 Pages 686-688
    Published: July 10, 1998
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Real-time data smoothing of noisy process signals using the moving average method and exponential smoothing filter are useful in process control. However, they have a large time phase delay, and control is very difficult to apply for processes having a large time delay. In this paper, a very simple way using modified moving average method is introduced. This method is applied to practical concentration signals. The proposed method is very easy to design, and an effective way to reduce a large time phase delay
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  • JUNZO YAMAMOTO, TAKASHI SASAKI, YOSHITOMO HANAKUMA, EIJI NAKANISHI
    1998 Volume 24 Issue 4 Pages 689-691
    Published: July 10, 1998
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    An application of the neural networks model is considered to estimate Research Octane Number of gasoline. It is one of the most important qualities of gasoline, and shows the anti-knocking performance of the fuel. Three methods for estimating Research Octane Number are developed in this study ; the empirical method using Research Octane Number of each component of gasoline, the statistical analysis method, and the neural networks model. It is shown that the neural networks model is effective in estimating Research Octane Number.
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  • MASAHIRO KINO-OKA, MASAO MIYA-OKA, MASAHITO TAYA, SETSUJI TONE, KANJI ...
    1998 Volume 24 Issue 4 Pages 692-695
    Published: July 10, 1998
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Batch cultures of photomixotrophic cells of Marchantia paleacea var. diptera were conducted at 25 °C under the initial conditions of glucose concentration of 20 or 40kg/m3, medium osmotic pressure of 520 or 830 kPa and mean incident light intensity of 0, 13 or 28 W/m2. The glucose concentration, osmotic pressure and mean light intensity in medium declined with increasing cell mass concentration, so that they became limiting factors against the cell growth during the cultures. A kinetic expression for the cell growth was presented by considering the effects of three limiting factors, and applied to the data obtained from the batch cultures. The calculation results fitted closely with the experimental data in the cultures.
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  • KEISUKE FUKUI
    1998 Volume 24 Issue 4 Pages 696-698
    Published: July 10, 1998
    Released: November 12, 2009
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    Flow-visualization measurements of the laminar flow in an expanded pipe with diameter-ratio 2 are carried out under the periodical unsteady condition. Flow transition to turbulence of 3 D structure is found to be related to mean Reynolds number, amplitude Reynolds number and frequency. Timevariations of the flow structures are also investigated.
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  • GUI-LIN ZHANG, TAMOTSU HANZAWA, NOBORU SAKAI
    1998 Volume 24 Issue 4 Pages 699-703
    Published: July 10, 1998
    Released: November 12, 2009
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    The effective thermal diffusivities of porous materials are calculated with correlative equations for effective thermal properties. To check these calculated results, the effective thermal diffusivities were measured using the Flash-Method by a finite element method under the same operating conditions for the porous materials. The calculated results agree closely with the data from the Flash-Method by numerical analysis.
    From the results of temperature distribution calculated numerically, the factors which influence the effective thermal diffusivity in the porous materials are mainly void fraction and the thermal conductivity ratio of two phases. It is pointed out that the standard for application of the Flash-Method to effective thermal diffusivities of porous materials is not only a ratio of size between a sample and vacant space, but also affected with the thermal conductivity ratio of two phases and the void fraction.
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  • YUTAKA YAMAZAKI, KATSUHIKO SHINOZAKI, YUSHI HIRATA
    1998 Volume 24 Issue 4 Pages 704-707
    Published: July 10, 1998
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The mechanism of solute incorporation into an ice-layer in freeze concentration with ice-lining was studied by changing the impeller speed N and the difference between the brine temperature and the freezing point of the feed solution ΔT in 10 kg/m3 CCNa solution. The effect of N on the apparent partition coefficient of the solute K, is more serious than that of ΔT. The growth rate of the ice layer is 10-710-6 m/s under the condition of ΔT = 2.87.9°C and N = 20400 min-1. The growth rate had a little effect on solute incorporation into the ice-layer. K values depended on the surface condition of the ice layer, which is effected by the mixing speed of the impeller. The ice layer formed at low mixing speed has a complex rough shape, and has much solute because of adhesion to a large surface area. Therefore, it is recommended that freeze concentration is performed by making an ice layer with smooth surface at high mixing speed.
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  • AKIRA SAJI, TADAAKI TANII
    1998 Volume 24 Issue 4 Pages 708-710
    Published: July 10, 1998
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    This letter shows the supplements in the paper authored by Saji et al. [published in Kogaku Kagaku Ronbunshu, 22, 1273-1280 (1996).] We correct here the momentum and CO2-conservation equations that were incorrect when they were transferred in the literature. In addition, we explain the reason of adoption of assumptions for physical quantities such as the Clathrate density, the CO2 solubility in seawater, and both the initial sizes of liquid-CO2 droplets and Clathrate balls released into the sea.
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