KAGAKU KOGAKU RONBUNSHU
Online ISSN : 1349-9203
Print ISSN : 0386-216X
ISSN-L : 0386-216X
Volume 41 , Issue 2
Showing 1-18 articles out of 18 articles from the selected issue
Editorial Note
Physical Properties and Physical Chemistry
  • Masaki Ota, Mika Hayashi, Yoshiyuki Sato, Hiroshi Inomata
    Type: Research Paper
    2015 Volume 41 Issue 2 Pages 73-77
    Published: March 20, 2015
    Released: March 20, 2015
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    Organic and inorganic extractions of citrus peels at 25°C and ambient pressure were carried out to fractionate the components and to estimate solubility parameters of each extract. The obtained extraction yield was plotted against solubility parameter of each extraction solvent and the plots were fitted by the Gauss waveform. The peak of the waveform showed an experimentally estimated solubility parameter for each extract. The results were comparable with the calculation methods proposed by Fedors and Hansen within a deviation of 20%, and a method was proposed for estimating the solubility parameters from extraction results.
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Transport Phenomena and Fluid Engineering
  • Takahiro Adachi
    Type: Research Paper
    2015 Volume 41 Issue 2 Pages 78-82
    Published: March 20, 2015
    Released: March 20, 2015
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    The flow characteristics of a liquid film rising along the outer surface of a rotating cone were determined experimentally. Previously, a rising liquid film was found to be atomized into a mist flow. In this study, the mechanism of mist formation was applied as a means to enhance oxygen mass transfer by atomizing the liquid and transporting oxygen from air to water through the atomized water droplets. Use of a rotating cone promotes the dual effects of mixing and mist flow, which leads to an increase in oxygen mass transfer because of the small diameter of mist droplets and the large surface area between liquid and gas. In addition, the flow pattern was found change from steady flow to unsteady flow as the rotation rate increases, and this greatly enhances the oxygen mass transfer.
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  • Yoshiro Inoue
    Type: Research Paper
    2015 Volume 41 Issue 2 Pages 83-90
    Published: March 20, 2015
    Released: March 20, 2015
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    The temporal change in fluid mixing patterns often appears to differ from the motion of fluid matter, especially in the case of unsteady flow. Fluid mixing patterns essentially concern the motion of a body comprising an infinite number of fluid particles. It cannot, therefore, be reduced to the motion of finite number of fluid particles. With the passage of time, the mixing pattern tends to take on a common pattern independent of the initial one. This fact strongly suggests the existence of a latent flow field for the pattern generation intrinsic to the fluid flow. However, traditional fluid dynamics lacks a framework to explain these problems appropriately. In this article, the new concept of velocity vector field is introduced which directly controls the motion of a fluid mixing pattern. With this concept, the phenomena of fluid mixing are grasped from a different point of view, and the essence of these phenomena is proposed more clearly.
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  • Haruki Furukawa, Yoshihito Kato, Ryo Nagumo, Yutaka Tada
    Type: Note
    2015 Volume 41 Issue 2 Pages 91-94
    Published: March 20, 2015
    Released: March 20, 2015
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    Since the power consumption of a concave turbine was thought to be the same as that of the Rushton turbine, it had not previously been studied. In this work, the power consumption of a concave turbine in a flat cylindrical vessel was measured, and the power number of the impellers could be correlated with the modified equations of Kamei et al. (1995, 1996). The power number of the concave turbine with baffle was found to be half that of the Rushton turbine.
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Particle Engineering
  • Shintaro Ishiyama
    Type: Research Paper
    2015 Volume 41 Issue 2 Pages 95-99
    Published: March 20, 2015
    Released: March 20, 2015
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    Chemical interface controlled dispersion and high-speed shearing water washing tests were implemented for the purpose of optimization of processing conditions with highly radioactive contaminated soils of over 570,000 Bq/kg in Fukushima and the following results were obtained.
    (1) Dispersion and miniaturization of the radioactive contaminated soil over 570,000 Bq/kg was enhanced in alkalized washing solution and optimization of pH control is required according to soil characteristic. From these results, it is recommended that pH 10.5, 10.7 and 11 are optimized pH for soil B, C and A, respectively.
    (2) Refinement of contaminated soils was also promoted by collision of contaminated soil particles toward washing machine walls and inter-particle collision during soil washing process and remarkable washing performance was achieved under the combination of dispersion and high-speed shearing washing condition with 50% (maximum) solid density in wash solution and for 1 h operation at least.
    (3) Remarkable well-ordered structural refinement and accumulation of the contaminated soil particle group with strong FP confinement were observed at the particle size under 10 µm after crack/washing process.
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  • Kenichi Arima, Yoshihiko Tsuchiyama, Takeshi Suzuki, Tetsuya Sawatsuba ...
    Type: Research Paper
    2015 Volume 41 Issue 2 Pages 100-106
    Published: March 20, 2015
    Released: March 20, 2015
    JOURNALS FREE ACCESS
    Though the world has abundant resources of brown coal, its moisture content is often high. Thus, a fluidized bed drying system using superheated steam for fluidizing gas has been developed as a high-capacity and low-energy-consumption drying technology. Brown coal contains many small pores and hydrophilic functional groups due to its low coal rank, and the form of water in brown coal is classified to four types: monolayer water, multilayer water, capillary water and free water. Therefore, it is important to understand the drying characteristics of water in brown coal in the design of steam fluidized bed dryers. In this research, experiments were carried out to evaluate the drying characteristics of three kinds of brown coal by using batch-type steam fluidized bed drying test equipment. As a result, a quantitative relationship between moisture content and drying characteristics was obtained. Most water was removed at a constant rate. Critical moisture content was around 35%-dry. The bed temperature for an equilibrium moisture content of 10%-dry was 115°C. A drying model of brown coal in which bed temperature and latent heat were given as functions of moisture content was proposed. The calculated results and the test results agreed well, and the model is expected to be effective in the design of steam fluidized bed dryers for brown coal.
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Separation Engineering
  • Masato Kawahara, Hideaki Mizuno, Makoto Yamada, Eiji Matuoka, Kazuho N ...
    Type: Research Paper
    2015 Volume 41 Issue 2 Pages 107-112
    Published: March 20, 2015
    Released: March 20, 2015
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    The quality standard for the fuel ethanol for gasohol, JIS K2190, was established in 2011 in Japan. In the bioethanol production process the product should be highly purified because the fermentation broth contains a lot of impurities. In this study, the behaviors of the ethanol quality and impurities in the distillation and refining process in a commercial bioethanol plant from waste wood were studied. The product quality was not stable due to the change in the quality of the each fermentation broth and it was shown that acidity and sulfur concentration should be improved. The pH control in reflux solution was attempted to improve the quality. By this pH control, acidity, electrical conductivity, water concentration, and sulfur concentration of product were improved. The behaviors of organic impurities were also studied. The concentration of the organic impurities was 5.0±2.0 g/L and the main components of the impurity were propan-1-ol, 2-butanol, and acetal. It was shown that the fusel oil removal from distillation process was effective to reduce the concentration of organic impurities.
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  • Yasuhito Mukai, Haiyan Pei, Masahiro Inoue, Yasuyuki Sato, Ryoji Fujii ...
    Type: Research Paper
    2015 Volume 41 Issue 2 Pages 113-120
    Published: March 20, 2015
    Released: March 20, 2015
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    To clarify the effect of the liquid environment on the filtration of fine particle suspensions by a sintered metal filter, filtration experiments of bacterial suspensions of Bacillus atrophaeus in water of various pH values or aqueous organic solvents of various concentrations were conducted, and the particle retention performances of the sintered metal filter were evaluated. In the water system, a decrease in pH led to a decrease in the absolute value of zeta potentials of both filter and bacterial particles. In an aqueous organic solvent system, an increase in concentration of organic solvents caused both a decrease in the absolute value of zeta potentials and a decrease in the permittivity of liquid medium. As a result, the particle retention performance tended to be improved by a decrease in the electrostatic repulsion between filter and bacterial particles in liquid. Moreover, the retention of bacterial particles by the sintered metal filter could be explained quantitatively by the interaction between the surfaces of filter and bacterial particles described through an analysis based on DLVO theory.
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Thermal Engineering
  • Shintaro Suzuki, Terumi Inagaki, Yanrong Li, Koshi Harada, Yukitaka Iz ...
    Type: Research Paper
    2015 Volume 41 Issue 2 Pages 121-130
    Published: March 20, 2015
    Released: March 20, 2015
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    Various thermo-physical properties of carbon nano-tube fluid (CNF, 1 wt%, 5 wt%) and their temperature dependency were elucidated the present research. Heat transfer by natural convection was also investigated in a horizontal enclosed rectangular container filled with CNF, which was heated at the lower surface and cooled at the upper surface. It was found that use of CNF decreased the heat transfer coefficient owing to the suppression of buoyancy-induced convection.
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  • Terumi Inagaki, Hiroki Kashiwa, Yanrong Li
    Type: Research Paper
    2015 Volume 41 Issue 2 Pages 131-139
    Published: March 20, 2015
    Released: March 20, 2015
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    Thermo-physical properties of the phase-change latent heat storage material sodium sulfate decahydrate were elucidated in order to examine its temperature dependency. Heat transfer by natural convection was also investigated in a horizontal enclosed rectangular container filled with sodium sulfate decahydrate, which was heated at the lower surface and cooled at the upper surface. It was found that the heat transfer coefficient of the liquid phase coincides well with the conventional heat-transfer correlation of natural convection heat transfer in a horizontal enclosed rectangular container by applying the values of thermophysical properties obtained in the present work.
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  • Kenichi Arima, Norihiro Fukuda, Ryuhei Takashima, Norito Katsuki, Tets ...
    Type: Research Paper
    2015 Volume 41 Issue 2 Pages 140-147
    Published: March 20, 2015
    Released: March 20, 2015
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    The world’s coal resources amount to about 900 billion tons, but about the half of this is sub-bituminous coal and brown coal. Brown coal often contains more than 50% moisture (wet basis) and its pre-drying in large volume with low energy consumption is a key technology for its efficient utilization. A fluidized bed dryer using superheated steam for fluidizing gas is suitable for this purpose. In a steam fluidized bed dryer, heat transfer tubes are installed in fluidized bed and brown coal particles are heated indirectly by saturated steam under pressure of around 0.5 MPa (saturation temperature 150°C) in these tubes. Since brown coal particles have a wide particle size distribution and are cohesive due to their high moisture content, it is important to estimate the heat transfer coefficient outside of heat transfer tubes in the design of steam fluidized bed dryers.
    In this study, basic cold tests using nitrogen as fluidizing gas were carried out with two kinds of brown coal with different moisture content. Influence of gas velocity and density of heat transfer tubes on the heat transfer coefficient was evaluated. In order to increase the heat transfer area, square fins were attached to the heat transfer tubes and their pitch was varied. Experimental results of heat transfer coefficient agreed well with the value estimated by the equation of Andeen and Glicksman by giving particle size and density as functions of the moisture content of brown coal. The heat transfer coefficient decreased with the increase in density of heat transfer tubes for high-moisture sticky particles, whereas it increased for dry particles. The fin effectiveness was smaller than the value calculated assuming the same heat transfer coefficient as bare tubes.
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Chemical Reaction Engineering
  • Satoshi Nishida, Ryo Nodo, Hiroshi Muta, Shizuma Kuribayashi
    Type: Research Paper
    2015 Volume 41 Issue 2 Pages 148-152
    Published: March 20, 2015
    Released: March 20, 2015
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    The effect of background pressure was investigated in silicon deposition by plasma jet CVD, a recently developed CVD method to deposit silicon at a deposition rate over 1 µm/s. The deposition rate, deposition structure, and crystallinity of the deposited silicon were examined at pressures between 133 and 800 Pa, and it was found that the deposition rate increased with pressure increase. Drastic changes in the deposition rate and crystallinity were observed between 267 and 400 Pa. Part of the gas flow was considered to be transitional flow at 267 Pa and below. Knudsen number was calculated to estimate gas flow in the deposition chamber, and the flow was estimated to be transitional at lower background pressure conditions. Mass transfer around substrates was suppressed by decrease of the gas velocity due to the change of flow. Concentration of deposition precursors was estimated by calculation using CHEMKIN-PRO software, and the concentration of SiH2 was found to increase with decrease in the background pressure. Variation of crystallinity was explained by variations in the gas velocity of the main jet and precursor concentrations. Thus, background pressure was an important factor in the use of plasma jet CVD.
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  • Daisuke Kobayashi, Tadaaki Sakamoto, Hideyuki Matsumoto, Tomoki Takaha ...
    Type: Note
    2015 Volume 41 Issue 2 Pages 153-156
    Published: March 20, 2015
    Released: March 20, 2015
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    This study focused on the effects of ultrasound on emulsification and enhancement of the synthesis of monodispersed fine particles of the conducting polymer polypyrrole by chemical oxidative polymerization. Monodispersed polypyrrole particles were synthesized in water by chemical oxidative polymerization with ultrasonic irradiation under conditions of low oxidant concentration and room temperature, and the effects of ultrasonic frequency on the morphology of synthesized polypyrrole particles and polymer yield were investigated. Polymer yield with ultrasound was larger than that without ultrasonic irradiation for the same reaction time, and ultrasound promoted the polymerization. At frequencies of high sonochemical efficiency, the average particle size decreased and the polymer yield increased. On the other hand, at the frequency of low sonochemical efficiency of 20 kHz, the polymerization reaction was enhanced and polymer yield increased.
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Biochemical Food and Medical Engineering
  • Kounosuke Hayashi, Yusuke Tomozoe, Kenji Nagai, Yoshiyuki Hiraishi, No ...
    Type: Research Paper
    2015 Volume 41 Issue 2 Pages 157-161
    Published: March 20, 2015
    Released: March 20, 2015
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    To detect a target protein in biological samples, a fusion protein was designed composed of a peroxidase from Arthromyces ramosus (ARP) and parts of the antibody-binding domains of Staphylococcus aureus protein A and Streptococcus protein G (PG). The ARP-PG fusion protein was successfully expressed by a heterologous protein expression system in Brevibacillus choshinensis. The fusion protein was secreted as an active form in culture media. The production of ARP-PG with higher peroxidase activity was observed by the addition of 5-aminolevulinic acid to the culture media. The performance of purified ARP-PG was validated by dot blotting for the detection of transferrin as a model target protein. A comparable performance in the dot blot analysis was attained using a culture supernatant containing crude but active ARP-PG, indicating the practicality of the Brevibacillus protein secretion system.
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Materials Engineering and Interfacial Phenomena
  • Kouhei Tsuruda, Shohei Kubo, Fumiya Matsuo, Kouichiro Sonae, Yoshihiro ...
    Type: Research Paper
    2015 Volume 41 Issue 2 Pages 162-166
    Published: March 20, 2015
    Released: March 20, 2015
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    We prepared and evaluated the heat characteristics, thermal expansion, water durability, transparency, and sealing strength of glasses comprising 30–80 mol%Li2B4O7, 10–40 mol%BaO, and 10–40 mol%P2O5. Addition of Al2O3 to the Li2B4O7–BaO–P2O5 glasses was found to improve their transparency. In particular, glass comprising 53.0 mol%Li2B4O7, 15.2 mol%BaO, 7.6 mol%P2O5, 24.2 mol%Al2O3 (LiBaP+24.2Al) had high transparency, high water durability, and a low thermal expansion coefficient equal to that of soda lime glass without the addition of a low thermal expansion ceramic filler. Furthermore, the LiBaP+24.2Al glass had high sealing ability (6.64 kgf/cm2) compared to lead glass (1.63 kgf/cm2).
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Energy
  • Tsuyoshi Yamamoto, Yoshiho Iwama, Ryosuke Imazato, Yusuke Asakuma
    Type: Research Paper
    2015 Volume 41 Issue 2 Pages 167-172
    Published: March 20, 2015
    Released: March 20, 2015
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    In this study, the combustion experiments using premixed CH4/air flame with and without the irradiation of a microwave have been carried out to investigate the effect of combustion enhancement by irradiating microwave power under equivalence ratios between 0.7 and 1.1. When the flame is radiated by a continuous wave microwave field of approximately 100 W, the consumption rates of CH4 and O2 increase and the generation rate of CO2 increases at all equivalence ratio conditions. The generation rates of H2 and CO increase at equivalence ratio 1.1. As a result, it is shown that the combustion flame is enhanced by irradiating microwave power. The optical emission intensities of OH radical and CH radical, which play an important role on combustion process, increase at 10 mm from the nozzle and they decrease at 25 mm from the nozzle, when the flame is radiated by a microwave. As a consequence, it is indicated that the combustion reaction is enhanced and the flame length is shortened by irradiating microwave power.
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General Research and Others
  • Masayuki Nakayama, Syuji Chyoki, Yamato Oyamada, Tune Sekiya, Kaoru Mi ...
    Type: Note
    2015 Volume 41 Issue 2 Pages 173-177
    Published: March 20, 2015
    Released: March 20, 2015
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    To popularize and establish renewable energy in a specific region, a micro-hydropower generation system was introduced in the Kuno River in Kuno, Odawara, Japan. With the goal of local supply and consumption of regional energy, suggestions for installation procedures, hardware and methodology that could be implemented by local residents are required. This study’s aim was to verify the specific installation procedures, proposed hardware and methodology. Investigations of energy-use plans, estimation of power generation potential, selection of appropriate technology and introduction of a micro-hydropower generation system were carried out. The procedures adopted exhibit an effective way of introducing a micro-hydropower generation system to the region.
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