Editor-in-Chief
Takao Tsukada (Tohoku University)

Associate (Editor-in-Cheifs)
Manabu Shimada (Hiroshima University)
Masahiro Shishido (Yamagata University)

Editors
Ryuichi Egashira (Tokyo Institute of Technology)
Jun Fukai (Kyushu University)
Choji Fukuhara (Shizuoka University)
Toshitaka Funazukuri (Chuo University)
Takayuki Hirai (Osaka University)
Jun-ichi Horiuchi (Kitami Institute of Technology)
Eiji Iritani (Nagoya University)
Yoshinori Itaya (Gifu University)
Noriho Kamiya (Kyushu University)
In-Beum Lee (Pohang University of Science and Technology (POSTEC))
Kouji Maeda (University of Hyogo)
Hideyuki Matsumoto (Tokyo Institute of Technology)
Nobuyoshi Nakagawa (Gunma University)
Masaru Noda (Fukuoka University)
Hiroyasu Ogino (Osaka Prefecture University)
Mitsuhiro Ohta (The University of Tokushima)
Eika (W. Qian Tokyo University of Agriculture and Technology)
Yuji Sakai (Kogakuin University)
Noriaki Sano (Kyoto University)
Naomi Shibasaki-Kitakawa (Tohoku University)
Ken-Ichiro Sotowa (The University of Tokushima)
Hiroshi Suzuki (Kobe University)
Nobuhide Takahashi (Shinshu University)
Shigeki Takishima (Hiroshima University)
Yoshifumi Tsuge (Kyushu University)
Tomoya Tsuji (Nihon University)
Da-Ming Wang (National Taiwan University)
Takuji Yamamoto (National Institute of Advanced Industrial Science and Technology (AIST))
Yoshiyuki Yamashita (Tokyo University of Agriculture and Technology)
Miki Yoshimune (National Institute of Advanced Industrial Science and Technology (AIST))

Editorial office:
The Society of Chemical Engineers, Japan
Kyoritsu Building, 4-6-19, Kohinata, Bunkyo-ku
Tokyo 112-0006, Japan
journal@scej.org

AIMS AND SCOPE:

Journal of Chemical Engineering of Japan, an official publication of the Society of Chemical Engineers, Japan, is dedicated to providing timely original research results in the broad field of chemical engineering ranging from fundamental principles to practical applications. Subject areas of this journal are listed below. Research works presented in the journal are considered to have significant and lasting value in chemical engineering.

Physical Properties and Physical Chemistry
Transport Phenomena and Fluid Engineering
Particle Engineering
Separation Engineering
Thermal Engineering
Chemical Reaction Engineering
Process Systems Engineering and Safety
Biochemical Food and Medical Engineering
Micro and Nano Systems
Materials Engineering and Interfacial Phenomena
Energy
Environment
Engineering Education

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Outstanding Paper Award Subcommittee of Journal of Chemical Engineering of Japan has assessed the 144 papers published in volume 45 into 2012, and the editorial board finally selected the five papers for JCEJ Outstanding Paper Award of 2012; those are the papers on “Onion-Like Structure of Viscoelastic Surfactant Solution Flow Induced By 4-Blade Paddle Impeller in a Vessel,” “Marangoni Flows in Polymer Solution Droplets Drying on Heating Surfaces,” “Numerical Simulations of a Bubble Rising through a Shear-thickening Fluid,” “Repeated Cooling Crystallization for Production of Microcrystals with a Narrow Size Distribution,” and “Influence of Polymer Decomposition Temperature on the Formation of Rare-Earth Free Boron Carbon Oxynitride Phosphors.”

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This contribution outlines the coherent and mathematical rigorous derivation of a generalized multi-scale model framework that is based on the Eulerian–Eulerian two-fluid methodology. By conditional volume-averaging (based on the immersed interface concept) and subsequent closure modeling, the two-phase flow features are first divided into an unresolved portion (on average or sub-grid scale) and a resolved portion, and then interpreted on a physical basis leading to constitutive relations for closure. The resulting two-fluid model framework HIRES-TFM (Hybrid Interface-Resolving Two-Fluid Model) exhibits the same basic structure as found for single-phase flow, which results in an inherently stable method and enables us to reuse numerical techniques that have been developed for single-phase problems. Moreover, the conceptual approach is both compatible to the Large Eddy Simulation (LES) framework for turbulence modeling, and is expandable to multi-scale flow scenarios, i.e. dispersed and segregated two-phase flows.

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In this paper, aggregation/dispersion behaviors of particle clusters in a non-uniform shear flow have been numerically analyzed using a thixotropy model for estimating local cluster size distributions. The effects of the viscosity of the dispersion media,the solid volume fraction and the Reynolds number on the cluster size distribution in a two-dimensional flow between parallel plates were investigated in order to find the primary factor determining the cluster size distributions. The viscosity of the dispersed media, the solid fraction and the Reynolds number were changed from 195 to 1950 Pa·s, from 0.10 to 0.25 and from 0.1 to 1.0, respectively. From the results, it is found for each case that large clusters are observed at the central area of the channel, but it becomes smaller near the wall where high shear is added. The cluster size near the wall is dominated by the shear stress. On the other hand, it is found that the cross-sectional averaged cluster size depends on the bulk velocity under the present conditions. As the cluster size near the wall can be correlated rather well with the bulk velocity, it is concluded that the bulk velocity is a convenient and useful factor for the dispersion/aggregation behaviors of fine particles under the present conditions.

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We have developed a technology for the production of non-agglomerated nanoparticles by collisions of agglomerates in supersonic flows. To form non-agglomerated nanoparticles, we conducted the following three experiments: the collision of agglomerated particles in the supersonic flow with a fixed metal plate, the collision of agglomerates in the supersonic flow with a vibrating metal plate, and the counter-collision of two supersonic flows containing agglomerated particles. The probability of the fragmentation of agglomerates by means of the collisions was investigated by counting the number of non-agglomerated particles and agglomerated particles in TEM images. The results of the experiments revealed that the collision of agglomerates with a plate generates the problem of particles remaining on the metal plate even under low-collision velocity, and the counter-collision of two supersonic flows containing agglomerated particles induces the highly efficient fragmentation of agglomerates.

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A mesh-stacked dielectrophoretic separator was used to selectively capture tungsten carbide particles from a mixture with diatomite particles. An AC voltage with a stable frequency (10 V, 100 kHz) applied to generate a dielectrophoretic force was superimposed on a low-voltage scanned frequency (1 V, 10 Hz–100 kHz) to analyze the impedance between the electrodes. Using this power source, the amount of captured particles and the selectivity of tungsten carbide could be estimated in situ, without the interruption of dielectrophoretic operation for any direct measurement. Simple empirical equations were derived to realize this estimation. It was observed that the weight fraction of the tungsten carbide in the captured particles tended to decrease with the amount of captured particles. Thus, the amount of captured particles should be intensively limited to achieve a targeted selectivity of tungsten carbide with a maximized captured amount. The simultaneous monitoring of the captured amount and the extent of the selectivity realized by the proposed method will be useful to determine an appropriate timing to terminate the separation operation.

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The aim of this study is to develop an artificial neural network (ANN) model for the successful control of a butter churning machine in industrial butter manufacturing. To model the manipulation skill of experienced operators, a three-layered ANN model with variable selection by a forward selection method was employed. Using four inputs including cream flow rate, fat content, aging time, and cream temperature, the ANN model properly predicted the churning speed within the prediction error of 7.0%, compared with that of experienced operators.

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This study was designed to evaluate the effect of oxygen transfer from gas phase to liquid phase on pigment production in Monascus ruber NBRC 32318 cultured in a liquid medium composed mainly of rice starch. The cells were cultured in 500-mL baffled Erlenmeyer flasks either by varying the shaking speed from 40 to 200 rpm with a fixed culture volume of 100 mL or by varying the culture volume from 50 to 250 mL with a fixed shaking speed of 120 rpm. Maximum pigment concentration was obtained at a shaking speed of 160 rpm and a culture volume of 100 mL. Cell mass concentration and pigment concentration, evaluated using the volumetric liquid-phase mass transfer coefficient (k_La) of oxygen, confirmed that both parameters increased with increase in k_La, but reached a plateau when k_La was more than 100 h⁻¹.

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Conducting polymers have been investigated widely for use in various applications because of their thermal and environmental stability and good electrical conductivity. As the rate of reaction in chemical oxidative polymerization for the synthesis of conducting polymers is very rapid, it is important to prepare spherical particles of the conducting polymer to maintain the reaction temperature at approximately 278 K. In this study, control of the reaction rate has been investigated, and a new method for the synthesis of polypyrrole particles using a water/oil emulsion is proposed. In this system, the diffusion of the monomer into a water droplet as the dispersed phase is the rate-determining step, and controls the reaction rate at room temperature. Monodispersed spherical polypyrrole particles were synthesized at room temperature using this method. The effects of organic solvent as the continuous phase on the synthesized polypyrrole particle size were also investigated. The diameter of the polypyrrole particle decreased with increasing viscosity of the organic solvent, and an empirical formula connecting the diffusion coefficient and average particle size is proposed.

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This study aims to understand the effect of pyrolysis temperature on the conversion of nitrogen species of pig compost containing a large amount of nitrogen. Various analysis techniques involving thermogravimetry, X-ray photoelectron spectroscopy, nuclear magnetic resonance, gas chromatography, total nitrogen analysis, and ion chromatography were performed to characterize the nitrogen conversion of pig compost. Pyrolysis of the sample was carried out in a fixed bed reactor by varying the temperature from 300 to 900°C. The nitrogen content of the residue was found to decrease with increasing pyrolysis temperature. In contrast, the conversion of organic-nitrogen species into N₂ and NO_x-precursors (HCN and NH₃) increased with increasing temperature. The significant release of NH₃ below 500°C can be related to the high protein content in the pig compost. The nitrogen yield as HCN was lower than 2% during pyrolysis below 500°C, and sharply increased to 4% at 900°C due to thermal cracking of pyrrole and pyridine in the residual char at high temperature. A majority of the nitrogen species in residual char is converted into N₂ during pyrolysis above 700°C.

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CaCO₃–Al(OH)₃ mixtures with different mixing ratios were calcined at different temperatures in the range of 1073–1473 K. To solidify the coal fly ash, it was mixed with the calcination product and water, and allowed to stand under saturated steam at 348 K for 3 d. The compressive strength of the solidified product using the calcination product was measured and compared with those of alumina and Portland cements. The calcination conditions and solidification conditions were examined to optimize the compressive strength of the solidified products. The calcination product reacted with fly ash to form crystalline Ca₃Al₂(SiO₄)(OH)₈, thus contributing to the high compressive strength of the solidified product. The leaching behavior of fly ash artificially contaminated with CrO₄²⁻, B(OH)₄⁻, AsO₄³⁻, and SeO₄²⁻, and solidified with the calcination product was examined. The solidified product formed from the calcination product prevented the leaching of all four oxoanions more effectively than the solidified products formed from other cements. The higher compressive strength of the solidified product facilitated this lower oxoanion leaching concentration from the solid.

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