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 (University of Hyogo)
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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The primary aim of this study is to understand the effect of SiO₂ on the fusibility and flow behavior of high-calcium coal ash and to investigate the mineral materials transformation at high temperatures. The changes of ash fusion temperature and viscosity at different coal–SiO₂ blended ratio were researched. The results show that the ash fusion temperature of Shanxin blending coal reaches the minimum when SiO₂/Al₂O₃ (S/A) weight ratio is 7.36 and acid to basic ratio (A/B) is 1.23. The mineral matters variation of Shanxin coal ash was compared with that of S/A=7.36 Shanxin blending coal ash by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results indicate that the fluidity of slag has been improved by the Si content in minerals. FactSage was used to predict the optimum value of flux and to demonstrate the mineral matters variation and these results agree well with the experimental values.

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Studies on bubble sizes in an aerated vessel have been conducted by several investigators for a Rushton turbine, but have rarely been conducted for large impellers developed recently. In this work, we tried to measure the bubble sizes in an aerated vessel agitated by a large impeller, which is a Maxblend or Hi-F Mixer, adding to a dual Rushton turbine as a standard configuration, using a high speed camera. As a result, it was found that there are not significantly large differences in the average bubble sizes for these three impellers. The average bubble sizes for the three impellers decrease almost proportionally with an increase in rotational speed and increase slightly with an increase in gassing rate, which corresponds to the results reported in the previous work. However, the bubble sizes at different axial positions for the two stage Rushton turbine decrease with an increase in the height. On the other hand, those for the Maxblend and Hi-F Mixer are approximately constant independent of axial position, which may indicate that large impellers can disperse almost uniform size bubbles throughout the vessel.

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Different scales of liquid mixing exist in bubble columns and it is very important to determine the prevailing mixing scale in each flow regime. Two independent parameters were found to exhibit a monotonous decline in the transition flow regime, which could be attributed to the decrease of the mixing length values L. In this work, a new parameter called “maximum number of visits in a region” (N_v^max) and the Kolmogorov entropy (KE) were extracted from the gas holdup time-series (60,000 points). The latter were recorded at a high sampling frequency (2,000 Hz) by a wire-mesh sensor. The measurements were performed in a narrow bubble column (0.15 m in i.d., clear liquid height=2 m) equipped with a perforated plate distributor (14 holes, ⌀4×10⁻³ m). Both parameters were capable of identifying concordantly the two main transition velocities at U_trans=0.022 and 0.112 m/s, which delineate the boundaries of gas maldistribution, transition and churn-turbulent regimes, respectively.

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The effects of additive polyacrylamide (PAM) on combustion characteristics of Al–H₂O-based propellants are investigated in air at atmospheric pressure. The combustion process and flame phenomena are recorded by a high-speed photography technique, and the condensed combustion products are analyzed by scanning electron microscopy (SEM) combined with energy dispersive X-ray (EDS). The results show that PAM is beneficial to improve the combustion performance of Al–H₂O-based propellants. The mixture of nano-sized Al powder and H₂O or H₂O with 1 wt% PAM can be ignited, but the combustion is not a self-sustaining process. The mixture of nano-sized Al powder and H₂O with 3 wt% PAM can be ignited with a self-sustaining combustion. Its burning rate is 4.07 mm/s. The mixture of nano-sized Al powder and H₂O with 3 wt% PAM still retains combustion when 33% nano-sized Al powder is replaced by micron-sized Al powder, while the burning rate is reduced to 0.5 mm/s. This work promotes a better understanding for the combustion processes of Al–H₂O-based propellants.

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The feasibility of a wafer-scale reactor for supercritical fluid deposition (SCFD) has been evaluated in a series of papers for mass production of Cu interconnects in ultra-large-scale integration (ULSI) based on two criteria: reactor throughput and film thickness uniformity on 12-inch wafers. This study experimentally extracts the reaction kinetics and transport properties of the source precursor within SCFD using a lab-scale flow reactor. The dependence of the growth rate (GR) on the source precursor and by-product (ligand of the precursor) concentrations was investigated. The source precursor exhibited Langmuir–Hinshelwood (LH) reaction kinetics, while increased by-product concentrations resulted in decreased GRs. The diffusion coefficient (D) of the source precursor under SCFD conditions was estimated using macrocavity analysis, and D was found to be approximately 10⁻⁷ m²/s. The obtained kinetic information will be used to design a mass production-scale reactor for SCFD of Cu (Cu-SCFD).

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The feasibility of a wafer-scale reactor for supercritical fluid deposition (SCFD) of Cu for interconnects in ultra-large-scale integration (ULSI) was evaluated for mass production based on two criteria: the throughput of the reactor (20 wafers/h) and the film-thickness uniformity on 12-inch wafers (>99%). The optimal configuration and size of a reactor adequate for mass production were determined using finite-element method (FEM) simulations with a reaction-rate equation and kinetic parameters from our previous study. Cu interconnects are conventionally fabricated by two processes: seed layer formation by sputtering, followed by gap filling by electroplating. SCFD can be used for seed-layer formation alone or for both seed-layer formation and gap filling. Here, the same conclusions were reached in both cases. A single-wafer reactor (SWR) was not suitable due to its low throughput, although excellent thickness uniformity could be expected. Stacking multiple wafers in a multi-wafer reactor (MWR) is thus preferable, where the throughput is a function of the number of stacked wafers. A closed MWR is acceptable due to its inherent film-thickness uniformity in addition to its high throughput. A continuous flow MWR imposes design issues on the reactor to achieve a uniform film-thickness distribution on the stacked wafers. A flow-channel MWR, where the precursor flows among the stacked wafers in parallel with the growing surfaces, was deemed suitable for mass production of ULSI Cu interconnects.

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The electro-intercalation behavior of Li⁺ ions has been studied in a solid Mg cathode in LiCl–KCl molten salt. Cyclic voltammetry, chronoamperometry, and chronopotentiometry were employed to investigate the formation behavior of Mg–Li alloys via the electro-intercalation of Li⁺ ions. The electro-intercalation of Li⁺ ions into an Mg electrode occurred through underpotential deposition (UPD) to form Mg–Li alloys. The diffusion coefficient of Li⁺ ions at the Mg cathode was calculated by using Cottrell’s equation. The phase of the Mg–Li alloy was determined from the Li content of the alloy. The growth of the alloy layer by electro-intercalation was very fast compared to conventional solid-phase diffusion. The measured Li content of the Mg–Li alloy is similar to the theoretical value calculated on the basis of supplied charges.

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The oxygen-transfer efficiencies or bubble size distributions of polyurethane membrane diffusers are closely related to the physical properties of the membranes and the operating conditions. The factors affecting the bubble sizes and pressure losses of micro perforated polyurethane membrane diffusers were investigated. The Sauter mean diameter and bubble size distribution of a diffuser depended on the needle diameter and type of polyurethane membrane. The Sauter mean diameter of an H-90 membrane was 1.33 mm which was smaller than those for other types of membrane. The pressures drop across the membrane depended on the immersion period in water and increased with soaking time. Changes in the Young’s modulus after water soaking and the hardness of the membrane are assumed to cause the pressure drop across the membrane.

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