KAGAKU KOGAKU RONBUNSHU
Online ISSN : 1349-9203
Print ISSN : 0386-216X
ISSN-L : 0386-216X
Volume 40, Issue 4
Displaying 1-13 of 13 articles from this issue
Editorial Note
  • 2014 Volume 40 Issue 4 Pages edit_4
    Published: July 20, 2014
    Released on J-STAGE: July 20, 2014
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  • Nobuyoshi Nakagawa, Takao Tsukada
    2014 Volume 40 Issue 4 Pages 273-274
    Published: July 20, 2014
    Released on J-STAGE: July 20, 2014
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    Outstanding Paper Award Subcommittee of Kagaku Kogaku Ronbunshu has assessed the 84 papers published in volume 39 into 2013, and the editorial board finally selected the four papers for Kagaku Kogaku Ronbunshu Paper Awards of 2013; those are the papers on “Comprehensive Combination Analysis for Screening of Significant Peptide Epitopes Using a Slide Glass Type-Exclusive Peptide Array from Milk Protein,” “Enhancement of LiBr-Water Absorption Heat Pump Performance by Supersaturated Fine Crystal Slurry,” “A Simple Scheme for Interface Tracking,” and “Development of Simulator for Bio-Propylene Synthesis Process.”
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Transport Phenomena and Fluid Engineering
  • Motoki Irikura, Munenori Maekawa, Shigeo Hosokawa, Akio Tomiyama
    Subject area: Transport Phenomena and Fluid Engineering
    2014 Volume 40 Issue 4 Pages 275-281
    Published: July 20, 2014
    Released on J-STAGE: July 20, 2014
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    Liquid slugs in oil and gas two-phase flow in hilly-terrain pipelines are often generated at V-shaped elbows and induce strong pressure fluctuation. The knowledge on characteristic of slugs such as slug frequency, velocity and length is required when designing the pipelines. In this study, numerical simulation based on a three-dimensional two-fluid model is carried out to predict liquid slugs generated at the elbows. The free surface model for the interfacial area density is employed to describe the interaction between the phases. Comparisons with experimental data show that the two-fluid model is able to well predict the liquid slug behavior in the ascending pipe at the downstream of the V-shaped elbow and the slug characteristics.
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  • Haruki Furukawa, Yoshihito Kato, Ryo Nagumo, Yutaka Tada, Makoto Sato
    Subject area: Transport Phenomena and Fluid Engineering
    2014 Volume 40 Issue 4 Pages 282-285
    Published: July 20, 2014
    Released on J-STAGE: July 20, 2014
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    To improve mixing performance, a cone-type draft tube based on the wind lens used in a wind power plant was proposed. Observation and measurement of the mixing pattern and power consumption with the cone-type draft tube revealed that it provided better mixing with lower power consumption.
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Particle Engineering
  • Toshiyuki Fujimoto, Ryo Kano , Shinya Yamanaka, Yoshikazu Kuga
    Subject area: Particle Engineering
    2014 Volume 40 Issue 4 Pages 286-291
    Published: July 20, 2014
    Released on J-STAGE: July 20, 2014
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    Langevin dynamics (LD) was used to simulate Brownian diffusion of aerosol particles with absorption walls on both sides. The results of LD calculations were compared with analytical solutions of the diffusion equation. Differences between the results obtained by LD calculation and the diffusion equation were organized by the dimensionless number Kn′ which was proposed to be the ratio of the path length of a Brownian particle λp to the distance between two walls L. When Kn′>10-4, results of LD calculation differed significantly from the analytical solution of the diffusion equation. When Kn′>10-2, the concentration of aerosol particles calculated by LD exceeded the analytical solution of the diffusion equation by 5% in relative error.
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  • Akinori Yoshihara, Shogo Nakano, Yasuhiro Konishi, Toshiyuki Nomura
    Subject area: Particle Engineering
    2014 Volume 40 Issue 4 Pages 292-298
    Published: July 20, 2014
    Released on J-STAGE: July 20, 2014
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    In a horizontal mixer, the adhesion of composite particles to the inner wall lowers the productivity of the composite particles. In this study, we thermodynamically evaluated the influence on the production yield of the surface free energy, which is related to the adhesion of processing materials to the inner wall. The surface free energy was calculated from the measured contact angles by taking into account acid-base interactions and surface roughness, and then the change in free energy of interaction ΔG when the processing materials adhere to the inner wall was estimated. A good correlation was found between the weight of silica particles adhering to the treated wall surface and ΔG. By contrast, on addition of a polymer with low softening point, the weight of adhering silica particles was almost constant regardless of ΔG, because the surface of the inner wall was coated with polymer. Furthermore, the yield loss of composite particles varied according to sequence in which the polymer was added. In conclusion, ΔG was shown to be an important factor in suppressing the adhesion of composite particles to the inner wall.
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  • Kenichi Arima, Isao Torii, Ryuhei Takashima, Tetsuya Sawatsubashi, Mas ...
    Subject area: Particle Engineering
    2014 Volume 40 Issue 4 Pages 299-305
    Published: July 20, 2014
    Released on J-STAGE: July 20, 2014
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    The world’s coal resources amount to around 900 billion tons, but half of this is sub-bituminous coal and brown coal. Brown coal often contains more than 50% (wet basis) moisture, which reduces the generating efficiency of brown coal-fired power plants. Therefore, pre-drying in large quantity 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, because this technology can simultaneously attain higher heat transfer coefficient, larger capacity of dryer, higher safety (absence of oxygen in the fluidizing gas) and more effective heat recovery by using evaporated steam as a heat source after compression. However, high-moisture coal is cohesive and it is important to know the influence of moisture content on its fluidization characteristics. In this research, experiments were carried out to evaluate the effect of moisture content on fluidization by visualization using cold fluidized bed test equipment. As a result, a quantitative relationship between moisture content and fluidizing characteristics was obtained by introducing angle of repose as an index of cohesiveness.
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Separation Engineering
  • Norikazu Namiki, Tsuyoshi Takagi, Naoki Kagi, Tatsuo Morita, Shunsuke ...
    Subject area: Separation Engineering
    2014 Volume 40 Issue 4 Pages 306-312
    Published: July 20, 2014
    Released on J-STAGE: July 20, 2014
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    Abatement of volatile organic compounds (VOCs) present in low concentration (less than 100 ppm) in various factory exhaust gases by spraying water containing acrylamide polyampholytes (APAs) conventionally employs two-fluid spray nozzles requiring compressed air to atomize the APA solution. The present study aims to develop a sophisticated compact VOC treatment system using one-fluid spray nozzles without compressed air. The fundamental absorption properties of APA solution for toluene vapor were first examined and found to depend on the inlet toluene concentration and the temperature of fed liquid. Electrospray (ES) and modulated electromagnetic field (MEF) methods were then applied to the one-fluid nozzle, and the results were compared with the removal rate of a two-fluid nozzle. Both ES and MEF methods were found to enhance the specific removal rate for toluene vapor, and the MEF method applied to the one-fluid nozzle displayed similar removal performance to the two-fluid nozzle when the residence time of the fed liquid in the applied electromagnetic field was optimized. PDPA measurements to determine droplet size distribution revealed that both ES and MEF methods had a reverse atomizing effect on droplets generated from the one-fluid spray nozzle.
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Energy
  • Motoyuki Osada, Hideo Kameyama, Makoto Sakurai, Kenji Watanabe
    Subject area: Energy
    2014 Volume 40 Issue 4 Pages 313-319
    Published: 2014
    Released on J-STAGE: July 20, 2014
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    To reduce energy consumption for air conditioning and thereby reduce the greenhouse gas emissions that are a major cause of global warming, a simulation was performed of personal air conditioning for office buildings by means of indirect evaporative cooling using desiccant dehumidification. It was found that a batch method of daily reactivation (desorption) of adsorbent allowed the weight and size of the system to be reduced to give a simplified configuration that could be built into an office partition. It was also found that use of waste heat in the regeneration of desiccant afforded energy saving. Compared with conventional air conditioning, the proposed system operated to give the same personal conditions of temperature and humidity was found to reduce the total heat load by over 12% and the power consumption by 37%.
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  • Yugo Ishizaki, Kosuke Nishida, Shohji Tsushima, Shuichiro Hirai
    Subject area: Energy
    2014 Volume 40 Issue 4 Pages 320-326
    Published: July 20, 2014
    Released on J-STAGE: July 20, 2014
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    Clogging of the cathode channel by water during operation of polymer electrolyte fuel cells (PEFCs) causes oxygen transport limitation and pressure drop. This phenomenon, known as “water plugging,” is a critical issue for high performance operation. To alleviate this problem, it is necessary to design a cathode channel with optimal structure and to control the surface wettability to promote water removal. In this study, the behavior of liquid water within the cathode channel of an operating PEFC was optically visualized using transparent cells with different channel structures and surface wettabilities. At the same time, the differential pressure between the cathode inlet and outlet and the cell voltage were measured, and the effects of channel structure and wettability on liquid water transport in the cathode channel were investigated. In a serpentine flow channel, both hydrophilic and hydrophobic coatings on the channel sidewall were found to effectively suppress water plugging. In the case of a parallel flow field, hydrophilic treatment of channel sidewall did not cause water plugging on the cathode side. However, hydrophobic treatment impeded the drainage of water accumulated in the channel and lowered cell performance.
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Environment
  • Nobusuke Kobayashi, Hisashi Hamabe, Yan-Liang Li, Yoshinori Itaya, Kao ...
    Subject area: Environment
    2014 Volume 40 Issue 4 Pages 327-332
    Published: July 20, 2014
    Released on J-STAGE: July 20, 2014
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    To clarify the effect of added sludge char on the bio-drying rate and bio-drying behaviour of sludge, a composting experiment with a small composting unit and a drying experiment with an air-blow drier were carried out. In the composting experiment, sludge char manufactured from a compost of sludge was mixed with dewatering sludge, and the moisture content, volatile matter of the compost and CO2 production during the fermentation was measured. In the air-blow drying experiment, addition of char to sludge was found to increase the dewatering rate during the fermentation and to promot the decomposition of organic matter in the sludge. When the air-blow drying was applied during the fermentation, dewatering performance improved by adding the char, but, the decomposition of organic matter was inhibited. Char addition also improved the drying rate of sludge, which increased with increase in the amount of char added.
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  • Ryo Shoji, Hikaru Kurokawa
    Subject area: Environment
    2014 Volume 40 Issue 4 Pages 333-341
    Published: July 20, 2014
    Released on J-STAGE: July 20, 2014
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    Humic substances, which account for the majority of dissolved organic matter in aquatic and soil, have the various properties due to the differences of its origin such as water quality, soil property and differences of ecosystem. In addition, humic substances affect the mobility and bioavailability of heavy metals in aquatic and soil ecosystem. In order to estimate the ecotoxicity induced by the copper in aquatic and soil ecosystems, it is important to analyze which characteristics of humic substances have strong influences on the existing form of heavy metals and also it is important to examine if these interactions affect the toxicity of heavy metals. The objective of this study is to analyze the binding of proton and cupric ion to three types of binding sites in the humic acids by NICA (Non-Ideal Competitive Adsorption)-Donnan model and to examine the influences of each humic acid on the algal (P. subcapitata.) growth inhibition by copper ecotoxicity.
    In terms of behavior of proton and cupric ion binding analyzed by NICA-Donnan model, behavior of proton and cupric ion binding differ from source to source of humic acids. It is due to the differences of molecular weight of humic acids, abundance of functional groups that become binding sites of humic acids. And also it is due to the number and density of electron donor groups or electron attractive groups because the electrostatic potential, which changes depending on electron donor groups or electron attractive groups, affect the amount of binding sites. In terms of the influences of humic acid on copper growth inhibition to P. subcapitata, the toxicity reduction levels are almost same among sources like liver, and soil.
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General Research and Others
  • Takahiko Ban, Yosuke Hatada, Kazuki Horie
    Subject area: General Research and Others
    2014 Volume 40 Issue 4 Pages 342-346
    Published: July 20, 2014
    Released on J-STAGE: July 20, 2014
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    The transition in droplet oscillation arising from the Marangoni effect was analyzed by applying the maximum entropy production principle. Entropy production was calculated by taking the volumetric flow of solution as thermodynamic force and the velocity of oscillating droplets as thermodynamic flow. The result of quantitative analysis showed good agreement with the transition point observed experimentally. This result reflects the universality of the maximum entropy production principle for predicting the transition points between different nonequilibrium states.
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