KAGAKU KOGAKU RONBUNSHU
Online ISSN : 1349-9203
Print ISSN : 0386-216X
ISSN-L : 0386-216X
Volume 23, Issue 5
Displaying 1-24 of 24 articles from this issue
  • Eiichiro Makino, Kazunobu Deguchi, Toshio Ohzawa, Satoshi Kawai, Kouji ...
    1997 Volume 23 Issue 5 Pages 611-617
    Published: September 10, 1997
    Released on J-STAGE: November 12, 2009
    JOURNAL FREE ACCESS
    Corrosion resistance and cracking behavior of 36 candidate materials have been investigated in Victorian Brown Coal Liquefaction Pilot Plant and the result is described herein. Test coupons for corrosion and cracking have been installed in each equipment in the 50 t/d pilot plant for Australian brown coal. Effects of environments and alloying elements on corrosion and environmental cracking are clarified and documented as references for material selection. Austenitic stainless steel for reactors and vapor/liquid separators, and titanium and high Ni alloy for the fractionating column are recommended as a result of this investigation. In addition to corrosion problems during operation, influences of shut down on corrosion are also discussed.
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  • Takashi Nakamura, Koji Machiya, Nobutaka Kawai, Kooji Kagara
    1997 Volume 23 Issue 5 Pages 618-623
    Published: September 10, 1997
    Released on J-STAGE: November 12, 2009
    JOURNAL FREE ACCESS
    In the optical resolution of an imidazole compound by formation of salt with L-10-camphorsulfonic acid, an efficient resolution method, namely the preferential dissolution method, was established. After precipitation of both isomers' salts completely from a minimum volume of ethanol aqueous solution, an ethanol aqueous solution is added to the Crystallization Solution stepwise to dissolve preferentially the unwanted isomer. Optical purity and yield do not depend on the addition method, but on the volume of solvent and are estimated with good agreement from their solubilities. In comparison with the conventional cooling method, (+) imidazole compound is steadily obtained with higher yield (50%) and higher optical purity (97%). On the basis of these results, the method is applied to a 1700 l-crystallizer using a power number per volume as a scale up factor and good reproducibility is conformed.
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  • Toshiro Tsuji, Toshiharu Shibata, Osamu Uemaki, Hironori Itoh
    1997 Volume 23 Issue 5 Pages 624-627
    Published: September 10, 1997
    Released on J-STAGE: November 12, 2009
    JOURNAL FREE ACCESS
    A method of measuring particle flow rates in gas-solids flow by piezoelectric probe has been improved. By detecting only the highest vibrating frequency caused by particle collision through a high pass filter, very high collision numbers can be counted. To access the performance of this probe, experiments measuring particle flow rates in a riser tube were carried out. The correlation equation between the counted collision number and the particle flow rate of these experiments is deduced. The estimated flow rates and real flow rates are compared and show good coincidence.
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  • Yoshitaka Sudo, Motoyuki Suzuki
    1997 Volume 23 Issue 5 Pages 628-634
    Published: September 10, 1997
    Released on J-STAGE: November 12, 2009
    JOURNAL FREE ACCESS
    Recently, public waterways have often been contaminated by numerous agricultural chemicals eluted from agricultural areas and golf links. In practice, however, the surface waters are complicated with coexisting agricultural chemicals and humic substances. Activated carbon adsorption is considered one of the solutions for removal of these agricultural chemicals.
    The present work aims to determine adsorption isotherms and rates of adsorption for five agricultural chemicals (CAT, TPN, isoprothiolane, 2, 4-D and diazinon), humic substances, and the coexistence of agricultural chemicals and humic substances on activated carbon.
    The isotherms are correlated with the Freundlich equation in the concentration ranges investigated. Surface diffusion was considered to be dominant, and the diffusion coefficients increased with increasing amount adsorbed. The amount of agricultural chemicals adsorbed and the effective surface diffusion coefficients for the coexistence of agricultural chemicals and humic substances were lower than those for single agricultural chemicals.
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  • Reiji Noda, Tsuyoshi Takano, Ichiro Naruse, Kazutomo Ohtake
    1997 Volume 23 Issue 5 Pages 635-643
    Published: September 10, 1997
    Released on J-STAGE: November 12, 2009
    JOURNAL FREE ACCESS
    In order to obtain fundamental data for alkali metal vaporization, the evaporation rate of alkali chlorides and alkali sulfates (NaCl, KCl, Na2SO4, K2SO4), which are major alkali compounds present in coal, were measured under inert, oxidizing and reducing atmosphere by using a thermobalance. A diffusion model was applied to obtain alkali metal evaporation data and identify an evaporating path and a rate controlling phenomena.
    Alkali chlorides evaporated as monomers and dimers. The evaporation rate is explained by a diffusion model. In the case of alkali sulfates, a dissociation reaction occurred simultaneously with evaporation as monomer. In inert and oxidizing atmospheres, the dissociation reaction was represented as
    M2SO4⇒2M+SO2+O2
    Evaporation rates can be calculated by a diffusion model in oxidizing atmosphere. In an inert atmosphere, however, when dissociation becames remarkable evaporation rate is controlled by the dissociation rate. Under a reducing atmosphere the expected reaction was represented as
    M2SO4+2CO⇒2M+SO2+2CO2
    This reaction does not reach equilibrium, so that the following reactions controll evaporation rate.
    M2SO4⇒2M+COS+5CO2
    COS+2CO2⇒SO2+3CO
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  • Masahiko Ishikawa, Yasuyuki Egashira, Hiroshi Komiyama
    1997 Volume 23 Issue 5 Pages 644-651
    Published: September 10, 1997
    Released on J-STAGE: November 12, 2009
    JOURNAL FREE ACCESS
    The very early stage of amorphous SiO2 thermal CVD from tetraethoxysilane (TEOS) oxidized by ozone were observed by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). Mono crystalline substrates of Al2O3, Si, and CaF2 were used for examining the dependence of growth mechanism on substrate. The thinnest film deposited on Al2O3 substrate was 1.6 nm thick, and was evaluated to already be a continuous film by XPS. Surface unevenness of Ra = 0.48 nm on this was observed by AFM. This unevenness increased untill the SiO2 film grew to be 4.2 nm thick, then decreased to be smooth within the resolution of AFM. The same phenomena were observed on Si and Al2O3 substrates.
    The film thickness at which smoothing stared were different depending on the substrates-4.2 nm for Si and 3.6 nm for CaF2, respectively. A simulation shows that the appearance of unevenness is explained by cone structure resulting from growthrate non-uniformity, and that smoothing is attributed to the effect of surface flow during deposition.
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  • Hiroyuki Kage, Hideaki Kawahara, Hironao Ogura, Yoshizo Matsuno
    1997 Volume 23 Issue 5 Pages 652-658
    Published: September 10, 1997
    Released on J-STAGE: November 12, 2009
    JOURNAL FREE ACCESS
    Microencapsulation of mono-dispersed stable kerosine droplets was carried out by complex coacervation of gelatin and acacia and the effect of operating condition on the membrane thickness of generated capsule is investigated. Mono-dispersed kerosine droplets were prepared using a porous glass membrane with narrow pore distribution. We succeeded in excluding the complicated influence of emulsification of core material on microencapsulation and in investigating the effect of operating conditions of the encapsulation process on capsule morphology separately by the use of mono-dispersed droplets as the core material.
    The drop size distribution and stability of the kerosine emulsion prepared by membrane emulsification were measured. The shape of the capsule is influenced sensitively by surfactant concentration and stirring rate. The number of cores included in a capsule increases, as the amount of kerosine increases.
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  • Hiroyuki Kage, Hideaki Kawahara, Hironao Ogura, Yoshizo Matsuno
    1997 Volume 23 Issue 5 Pages 659-665
    Published: September 10, 1997
    Released on J-STAGE: November 12, 2009
    JOURNAL FREE ACCESS
    Mono-dispersed stable kerosine droplets were prepared by a membrane emulsification method with microporous glass, and their microencapsulation was carried out by complex coacervation of gelatin and acacia. The effects of acetic acid dosage, cooling rate, addition time of core material in the encapsulation process, heating rate, and dosages of sodium hydroxide and formaldehyde in the hardening process on membrane thickness and the number of cores of generated microcapsules are investigated systematically.
    It is clear that the 30 to 20°C range in the cooling process is an important temperature range for microencapsulation of kerosine droplets. Low dosage of acetic acid and low cooling rate reduce the number of core included in the capsule, and the membrane thickness and the number of cores in the capsule are almost independent of the operating conditions in the hardening process. Further, the results obtained in the encapsulation of the liquid drop are compared with the data of solid core microencapsulation.
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  • Yasuo Kousaka, Toshiyuki Nomura
    1997 Volume 23 Issue 5 Pages 666-672
    Published: September 10, 1997
    Released on J-STAGE: November 12, 2009
    JOURNAL FREE ACCESS
    In addition to the classical thermodynamical theories on nucleation, a relationship between number concentration of particles generated by homogeneous nucleation and operating conditions are theoretically and experimentally studied. A model, where the number concentration of particles generated by homogeneous nucleation n* is determined so that the generation rate of monomers (as precursors) G* is equal to their vanishing rate at monomer concentration C*, which corresponds to a critical supersaturated state of nucleation, is proposed. The cell model, which is often used 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 experimental results obtained for silver particles generation by a reduction method are found to qualitatively support the present model.
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  • Yasuo Kousaka, Toshiyuki Nomura, Shinji Hasebe, Ken Tanaka
    1997 Volume 23 Issue 5 Pages 673-678
    Published: September 10, 1997
    Released on J-STAGE: November 12, 2009
    JOURNAL FREE ACCESS
    Homogeneous nucleation in system containing seed particles is analyzed. The model proposed by the present authors (Kousaka and Nomura, 1997) is applied in the analysis taking additional modification into account where spatial distribution of nuclei is assumed not to be uniform, but random. Experiments, where the diameter and number concentration of seed particles and the generation rate of monomer (precursor) were varied, were performed to verify the analysis. It is found that present analysis can predict well the operating conditions where 1) homogeneous nucleation is predominant, 2) particle growth is predominant and 3) homogenous nucleation and paricle growth coexist.
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  • Fumimaru Ogino, Yasushi Saito, Takeshi Yoshida, Kazuaki Masuda, Kei Mi ...
    1997 Volume 23 Issue 5 Pages 679-686
    Published: September 10, 1997
    Released on J-STAGE: November 12, 2009
    JOURNAL FREE ACCESS
    An experimental investigation of heat transfer and fluid flow on a heated rotating disc in a stagnation flow has been carried out. From the measured results of heat transfer coefficients, the conditions of transition from the region in which the stagnation flow is dominant to the region in which the forced convection by the disc rotation is dominant, and the transition from the forced convection dominant to the natural convection dominant region are determined. Empirical equations of Nusselt numbers for the three regions are also given. Flow visualizations by shadowgraphy and laser induced fluorescence techniques show that circumferential vortices due to buoyancy force appear on a rotating disc in the natural convection dominant region. The circumferential vortices are generated in the central region of the disc and move outwards in a radial direction. The radial velocity of the circumferential vortices is calculated from the time correlation of the temperature fluctuation. The calculated results indicate that the circumferential vortices have constant velocity at the outer region of the disc.
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  • Junya Kano, Fumio Saito, Atsuko Shimosaka, Jusuke Hidaka
    1997 Volume 23 Issue 5 Pages 687-693
    Published: September 10, 1997
    Released on J-STAGE: November 12, 2009
    JOURNAL FREE ACCESS
    The vibrating motion of a particle bed and percolation of a tracer particle with relatively small size in the cyclic vibrating field are investigated using two-and three-dimensional simulation techniques based on the particle element method (PEM). The vibration and percolation behavior are influenced by the dimension in the simulation. That is, the particles motion simulated three dimensionally is animated in comparison with that simulated two dimensionally. In addition, the three dimensional simulation enables us to cause a mutual exchange of particles in the bed. On the other hand, the tracer particle is percolated towards the bottom of the bed in the three dimensional simulation, while it remains in the vicinity of the surface layer in the two dimensional one. According to the model analysis of the rearranging distance of particles in the bed in which the tracer is able to percolate into the bed, the distance analyzed three dimensionally is wider than that analyzed two dimensionally. The discrepancy in the vibration and percolation behavior is attributed to the difference in the two and three dimensional porosity and their space structure formed in the vibrating bed.
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  • Koichiro Shiomori, Yoshinobu Kawano, Yoshinari Baba, Hiroaki Mitani, Y ...
    1997 Volume 23 Issue 5 Pages 694-700
    Published: September 10, 1997
    Released on J-STAGE: February 19, 2010
    JOURNAL FREE ACCESS
    Autoxidation of linoleic acid was carried out in the temperature range from 323 K to 343 K using a bubble column reactor. A slow initial increase in hydroperoxide at low concentration range of hydroperoxide (induction period) and a rapid increases in hydroperoxide at high concentration of hydroperoxide after a certain time (acceleration period) were observed during the reaction. The experimental results are analyzed by the radical chain reaction model proposed. The rate equation of hydroperoxide formation with two apparent kinetic constants is developed to explain the autoxidation rate of linoleic acid. Effects of UV irradiation in the presence or absence of TiO2 powder are also studied. Autoxidation of linoleic acid was accelerated by UV irradiation and especially by the photocatalytic effect of TiO2. A remarkable acceleration effect by UV and photocatalysis of TiO2 is observed in the induction period and these effects are enhanced at lower temperature.
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  • Kotaro Tanaka
    1997 Volume 23 Issue 5 Pages 701-706
    Published: September 10, 1997
    Released on J-STAGE: November 12, 2009
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    The alkali metal thermal to electric converter (AMTEC) is a static energy conversion device of thermal to electric energy using a beta “-alumina solid electrolyte. This paper discusses a thermal design for AMTEC cells, which employ a capillary wick for sodium recirculation. The selection of optimum wick pore size, expected capillary force, and flow resistance data are examined. A thermal analysis program is developed, and heat transfer process and conversion efficiency are discussed. The calculated result indicates wick recirculation-type AMTEC cells, which have single and multiple beta” -alumina tubes, can operate over a temperature range up to 1100 K and the expected conversion efficiency is 20-25%.
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  • Kenji Ukai, Ken Toyokura
    1997 Volume 23 Issue 5 Pages 707-712
    Published: September 10, 1997
    Released on J-STAGE: November 12, 2009
    JOURNAL FREE ACCESS
    Precipitation of calcite is studied by reaction between aqueous solutions of calcium chloride and sodium carbonate in a batch crystallizer. The calcium carbonate intermediate generated by reaction between these solutions was rapidly transformed to calcite by addition of sodium chloride crystals under some operational conditions, which are determined in this study, and then calcite gradually grew in the intermediate slurry. The crystal growth rate of calcite is obtained as 1.2 μm/min when enough amount of calcium carbonate intermediate coexists. The crystal growth rate of calcite is kept constant by the fact that the concentration of calcium ion in the reacting solution is saturated by dissolution of the calcium carbonate intermediate.
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  • Fumimaru Ogino, Yasushi Saito, Hajime Matsumoto
    1997 Volume 23 Issue 5 Pages 713-719
    Published: September 10, 1997
    Released on J-STAGE: November 12, 2009
    JOURNAL FREE ACCESS
    An experimental investigation of flow near a rotating disc with stagnation flow has been carried out. Flow visualization indicates that a circulating flow appears on the disc and fluctuates with a frequency of half to one sixth of that of the rotating disc. Measurements of circumferential velocity have been made by a laser Doppler velocimeter. The result shows that the transition to turbulent flow occurs at a local rotational Reynolds number of 1.5 × 105, and the velocity fluctuates with a frequency 28-times as large as that of the rotating disc in the transitional region. The time smoothed circumferential velocity in the laminar region is in good agreement with the theoretical value of the free disc, irrespective of the Reynolds number of the approaching flow.
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  • Katsumi Tochigi, Shimpei Kurita, Masami Ohashi, Kazuo Kojima
    1997 Volume 23 Issue 5 Pages 720-725
    Published: September 10, 1997
    Released on J-STAGE: November 12, 2009
    JOURNAL FREE ACCESS
    Infinite dilution activity coefficients (353.15393.15 K) of six solvents (benzene, toluene, p-xylene, cyclohexane, acetone and methylethylketone) and activity coefficient at finite concentrations (353.15 K, 373.15 K) of these solvents in poly (ethylene oxide) are measured using gas-chromatographic method. The experimental data are then correlated by a polymer-ASOG model.
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  • Chiaki Kuroda, Fumiyoshi Goto, Kohei Ogawa
    1997 Volume 23 Issue 5 Pages 726-729
    Published: September 10, 1997
    Released on J-STAGE: November 12, 2009
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    In a job-shop scheduling method proposed in a previous paper using a three-layered neural network optimized by a genetic algorithm, an improved method where the mutation probability is manipulated in a simulated annealing-like way is introduced to escape from a local optimum solution. Its effect on the variety of networks is investigated from the viewpoint of the structure of gene arrangement, and the efficiency of the present improvement is made clear. As a result, easy escape from a local optimum of 981 hours is realiged. Moreover, some excellent gene blocks (blocks of connection weights) for superior schedules are discovered.
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  • Wei-Ping Zeng, Eiji Iritani, Toshiro Murase
    1997 Volume 23 Issue 5 Pages 730-732
    Published: September 10, 1997
    Released on J-STAGE: November 12, 2009
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    Permeation experiments of ultrapure water were conducted under periodic pressure conditions using a packed bed obtained by dispersing submicron particles of polymethyl methacrylate (PMMA) uniformly into a packed bed of particles of White Alundum. It is clearly demonstrated that washing performance under periodic pressure conditions where the permeation pressure is applied periodically is improved dramatically, compared with that under constant pressure conditions. It is also shown that the effect of periodic pressure operation is especially noticeable in the initial stage of the pressurizing period, and that a pressurizing time smaller than 2 min is very effective under conditions examined in this study.
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  • Phan Do Hung, Teruyuki Masawaki, Setsuji Tone
    1997 Volume 23 Issue 5 Pages 733-737
    Published: September 10, 1997
    Released on J-STAGE: November 12, 2009
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    Using poly (dimethylsiloxane) membranes, the sorption amount of dimethylcarbonate-methanol mixture into the membranes at the equilibrium was measured and pervaporation of dimethylcarbonate-methanol mixture was performed. The equilibrium concentration of the mixture in the membrane increased with increasing dimethylcarbonate concentration in the liquid phase. The membrane was permselective to dimethylcarbonate in the range of dimethylcarbonate weight fraction in the feed up to 0.8 in pervaporation. The permeation fluxes of both components increased and the separation factor remained almost constant as the operating temperature increased.
    The permeation fluxes through the membrane were analyzed by the solution-diffusion model considering the swelling effect of dimethylcarbonate on the membrane, and diffusion coefficients and swelling parameters were evaluated. The calculated values of separation factor based on the model were in good agreement with the experimental ones.
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  • Yasuhiko H Mori
    1997 Volume 23 Issue 5 Pages 738-739
    Published: September 10, 1997
    Released on J-STAGE: November 12, 2009
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    This letter gives some critical comments on the paper in the title authored by Saji et al. [published in Kagaku Kogaku Ronbunshu, 22, 1273-1280 (1996)]. We point out that the momentum and the CO2-conservation equations used to simulate the dissolution of CO2 in the sea may be seriously erroneous. An inconsistency between these equations and some of the results of the simulation is suspected. Questions are raised on the authors' assumptions of physical quantities such as the hydrate density, the CO 2-in-seawater solubility, and the initial size of liquid-CO2 droplets or hydrate balls released into the sea.
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  • 1997 Volume 23 Issue 5 Pages e1a
    Published: 1997
    Released on J-STAGE: November 12, 2009
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  • 1997 Volume 23 Issue 5 Pages e1b
    Published: 1997
    Released on J-STAGE: November 12, 2009
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  • 1997 Volume 23 Issue 5 Pages e1c
    Published: 1997
    Released on J-STAGE: November 12, 2009
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