研究者業績

Koji Arafune

  (新船 幸二)

Profile Information

Affiliation
University of Hyogo
Degree
博士(工学)(早稲田大学)

J-GLOBAL ID
201501045982512459
researchmap Member ID
B000244447

External link

Papers

 93
  • Ippei Tsushima, Kohei Kubota, Kento Katogi, Kanami Nakamoto, Kouji Maeda, Koji Arafune, Kazuhiro Itoh, Takuji Yamamoto, Syogo Taguchi, Hideo Miki
    Chemical Engineering and Technology, 46(2) 357-362, Feb, 2023  
    Three different salt crystals (K2SO4, KCl, and Na2SO4·10H2O) were produced via batch cooling and continuous crystallization using a bench-scale crystallization device, in order to elucidate the mechanism of inclusion of the mother liquor as a function of crystal size. The inclusion ratio of the mother liquor was higher at small sizes and decreased with crystal growth. All results were represented by the previously proposed model of core-aggregation and shell-growth processes for the three different salt crystals. Crystals with small Vickers hardness aggregated with each other, and the inclusion ratio of the mother liquor of aggregated grown crystals was high for all three salt crystals tested herein.
  • Yasushi Hotta, Ryoichi Nemoto, Keisuke Muranushi, Yujun Zhang, Hiroki Wadati, Keita Muraoka, Hiroshi Sakanaga, Haruhiko Yoshida, Koji Arafune, Hitoshi Tabata
    Applied Physics Letters, 120(23) 232106-232106, Jun 6, 2022  
    The interface properties of strongly correlated electron system/band semiconductor junctions were investigated in the La1−xSrxVO3/p-Si(100) structure. Spectroscopic observations show that the electronic structure of the interface is typical of insulator/semiconductor junctions for x ≤ 0.2 and Schottky junctions for x ≥ 0.25. For the forward current density–bias voltage (J–V) characteristics, energy barriers that were otherwise unexplainable by spectroscopy were estimated from the thermionic emission model fitting of the J–V characteristics, indicating that the injected carriers from Si to La1−xSrxVO3 can also feel the correlation force of Coulomb repulsion at the interface.
  • Ippei Tsushima, Kouji Maeda, Takuji Yamamoto, Kazuhiro Ito, Koji Arafune, Syogo Taguchi, Hideo Miki
    CHEMICAL ENGINEERING & TECHNOLOGY, 45(5) 985-989, May, 2022  
    Continuous crystallization via indirect cooling of potassium aluminum sulfate dodecahydrate (KAl(SO4)(2)center dot 12H(2)O) was carried out using a draft tube-type crystallizer with a circulation flow path. The crystallizer was equipped with a newly designed system to monitor the degree of supersaturation in the circulation channel. The average degree of supercooling and growth rate were measured. The crystal growth rates calculated by the population balance model and the supersaturation monitor were different but close. The average supersaturation calculated from the supercooling degree and the solubility data in the literature was 0.19 g per 100 g H2O. This system is also expected to be applied to industrial crystallization where impurities are present.
  • Ippei Tsushima, Kouji Maeda, Koji Arafune, Kazuhiro Itoh, Takuji Yamamoto, Shogo Taguchi, Hideo Miki
    JOURNAL OF CHEMICAL ENGINEERING OF JAPAN, 55(4) 188-192, Apr, 2022  
    To understand the inclusion of mother liquor in crystals at different sizes, the continuous crystallization of potassium sulfate was investigated. A bench-scale crystallizer of the draft-tube type was employed for both batch cooling and continuous crystallizations. A standard solution of potassium sulfate was employed as the saturated solution at 323 K. The batch cooling crystallization was first performed at 283 K at a rate of 5 K/h, after which the continuous crystallization was performed at 283 K at two different residence times. The crystal size distribution (CSD) of potassium sulfate crystals and the inclusion ratio of mother liquor in the crystals at different sizes were measured. The average size of the crystals was approximately 400-500 mu m, and the inclusion ratio was less than 1% for all sizes; however, the small and large crystals contained a considerable amount of mother liquor, and the specific crystals that exhibited the lowest inclusion ratios were investigated. Moreover, an impurity distribution model for the suspension crystals was proposed based on coreaggregation and shell-growth processes.
  • Kouji Maeda, Yosuke Naito, Hidetoshi Kuramochi, Koji Arafune, Kenji Iimura, Shogo Taguchi, Takuji Yamamoto
    JOURNAL OF CHEMICAL THERMODYNAMICS, 165, Feb, 2022  
    A new method for determining the liquidus and solidus pressures of mixtures of C18's unsaturated fatty acids at constant temperatures was proposed, and three binary isothermal SLE data under high-pressure were systematically measured in this study. The liquidus and solidus temperatures of oleic acid, linoleic acid and alpha-linolenic acid commonly rise above their normal melting temperatures when pressure is increased. This new high-pressure experimental system can closely track pressure in real time during pressure swinging changes, making it simple to measure liquidus and solidus pressures using this dynamic measurement method due to fast responsiveness of pressure. In this study, the liquidus pressures of pure oleic acid, linoleic acid, alpha-linolenic acid and three binary mixtures consisted of oleic acid, linoleic acid alpha-linolenic acid at constant temperature were determined. The isothermal SLE were first correlated based on a simple thermodynamic model. (C) 2021 Elsevier Ltd.

Misc.

 202

Presentations

 14

Research Projects

 3

Industrial Property Rights

 3