Editors: Ryuichi Egashira (Tokyo Institute of Technology) Jun Fukai (Kyushu University) Choji Fukuhara (Shizuoka University) Takayuki Hirai (Osaka University) Masahiko Hirao (The University of Tokyo) Jun-ichi Horiuchi (Kitami Institute of Technology) Eiji Iritani (Nagoya University) Yoshinori Itaya (Gifu University) Hideo Kameyama (Tokyo University of Agriculture and Technology) Masahiro Kino-oka (Osaka University) Toshinori Kojima (Seikei University) In-Beum Lee (Pohang University of Science and Technology (POSTEC)) Kouji Maeda (University of Hyogo) Shin Mukai (Hokkaido University) Akinori Muto (Osaka Prefecture University) Nobuyoshi Nakagawa (Gunma University) Hiroyasu Ogino (Osaka Prefecture University) Naoto Ohmura (Kobe University) Mitsuhiro Ohta (The University of Tokushima) Yuji Sakai (Kogakuin University) Noriaki Sano (Kyoto University) Masahiro Shishido (Yamagata University) Richard Lee Smith, Jr. (Tohoku University) Hiroshi Suzuki (Kobe University) Shigeki Takishima (Hiroshima University) Yoshifumi Tsuge (Kyushu University) Tomoya Tsuji (Nihon University) Da-Ming Wang (National Taiwan University) 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 email@example.com
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
A cooling experiment using a small-scale tank with conical bottom has been conducted in order to analyze the cooling characteristics of a cream cooling storage tank, and consider an improved impeller. A cream-like liquid having viscosity adjusted with carboxymethylcellulose (CMC) was used as the test liquid. For the stirring impeller, a special anchor impeller was employed, which was equipped with blades which scrape off the tank walls at the upper part, and blades which scrape up from the bottom at the lower part. The effects on cooling rate have been measured for 4 impeller shapes and their rotational directions. The average temperature profile index ITP and the upper/lower temperature difference profile index IDTP are defined and used to evaluate cooling rate and uniformity inside the tank. As a result, it has been found that, with pressing by the upper blades and scraping up by the lower blades, an impeller with a 90° phase difference between the upper and lower blades is superior. When this result is applied to the design of an actual manufacturing tank, and comparative tests are conducted on rotational direction, the results are as expected based on the results with a small-scale experimental tank, and these results can be expected to improve the product quality and production efficiency.
A method for analyzing quantitatively the effects of particle shape and size distribution on the size segregation of particles using Distinct Element Method simulation, which employ spherical particles with an equivalent friction coefficient to efficiently incorporate the effect of particle shape, is proposed. The simulation of container filling is carried out for particles having a continuous particle size distribution, including different particle shapes and geometric standard deviations σg. In order to quantitatively evaluate the particle size segregation into the active layer, two metrics are used: a new segregation index indicating the degree of segregation and the percolation index, which evaluates the percolation segregation. Using spherical grass beads, and irregular-shaped Ise sand and alumina particles, the filling behavior of particles into a container are simulated, and the segregation index of those filling layer are estimated. Although increasing the irregularity of particles reduce the mobility of particles, the segregation index of those filling layer conversely became large. Further when the size distribution is wider, the segregation of fine particles increases considerably, but the segregation indexes of coarse particles do not vary; moreover, the high index values of the fine particles become smallest for a σg of around 1.38.
The adsorption of chicken egg-white lysozyme onto biomass charcoal powder (BCP), which was prepared from plant biomass wastes such as dumped adzuki beans and bamboos by pyrolysis without combustion under a nitrogen atmosphere and grinding with a jet mill, has been examined. The adsorption isotherms were successfully correlated by the Freundlich equation. The amount of lysozyme adsorbed on BCP is dramatically dependent upon the solution pH and temperature. A maximum adsorption is observed near neutral pH, suggesting that the adsorption is mainly attributable to the electrostatic interaction between the positive charge of enzymes and the negative charge on the surface of BCP. Plots of the amount of lysozyme adsorbed versus temperature exhibit an optimum temperature. The BCP is characterized by Raman spectroscopy, SEM, specific surface area, ζ potential, solid-state CP/MAS 13C-NMR spectroscopy, and X-ray photoelectron spectroscopy.
Numerical analysis has been conducted to characterize thermal plasma generated by a novel long direct current (DC) arc discharge system for waste treatment. Effects of arc current, gas flow rate, confinement tube diameter, and electrode gap distance on the temperature distribution of thermal plasma were investigated. From the numerical results, the design variables were expected to control over waste treatment processes effectively in the long DC arc thermal plasma. A broad high temperature distribution with low power consumption was predicted in the case of large diameter of the plasma confinement tube, because the less intrusion of cold gas into the arc column leads to the expanding of current density profile in the radial direction. In the downstream region, the fraction of low temperature area to cross sectional area that hinders the decomposition of wastes was decreased with increasing the electrode gap distance.
Multiple time delays and complex interactions among loops constitute a major problem in the design of controllers for multivariable processes. This paper proposes a new IMC method based on an equivalent model using the Smith delay compensator for multivariable systems with multiple time delays. By decomposing the MIMO systems into a set of equivalent independent single loops including delay compensations, poor performance caused by interactions and time delays is avoided. Using these single loop controllers, PID controllers with a first-order lag filter structure are designed; moreover, they can be potentially employed in various industrial applications. Simulation results demonstrate the flexibility and effectiveness of the proposed method.
In chemical plants, soft sensors are widely used to estimate process variables that are difficult to measure online. The predictive accuracy of soft sensors decreases over time because of changes in the state of chemical plants, and soft sensor models based on time difference (TD) have been constructed to reduce the effects of deterioration with time, such as drift. However, although a TD interval of training data affects the predictive accuracy of TD models and the predictive accuracy depends on a TD interval of new data, the way to determine an optimal TD interval of training data for that of new data remains to be clarified. We, therefore, propose an automatic selection method of an appropriate TD interval of training data based on a new cross-validation method. When training data are divided into data for the model construction and validation data in cross-validation, we change not only TD intervals of model construction data, but also those of validation data, and TD models and their predictive accuracy were saved for each TD interval. In prediction, TD of new data are entered into the TD model with the highest predictive accuracy for the validation data TD interval that is the same as the new data TD interval. We analyzed dynamic simulation data and real industrial data and confirmed that the predictive accuracy of TD models increase using the proposed method.
Positive interactions between Bifidobacterium longum or Bifidobacterium breve and Propionibacterium freudenreichii that enhance cell growth were evaluated using a co-cultivation system. The total dry cell weight of B. longum and P. freudenreichii from co-cultivation was 10.6 g. This value is 1.2-fold higher than the sum (9.1 g) of the maximum dry cell weights obtained from the cultivation of each bacterium. Currently, the total dry cell weight of co-cultivated B. breve and P. freudenreichii was 21.3 g. The total dry cell weight of B. breve and P. freudenreichii is 1.6-fold higher than the sum (13.2 g) of the maximum dry cell weights from two single cultivations of each bacterium. These data are direct evidence for a cooperative interaction between the two microorganisms.
A passive micromixer with wavy channel walls with a sinusoidal variation is proposed, and numerical simulations based on Navier–Stokes equations are carried out for Reynolds numbers (Re) from 0.1≤Re≤30. Ethanol and water are used as the working fluids for mixing. A mixing index is employed to evaluate the performance of the micromixer. A different realization of chaotic mixing based on Dean vortices is observed with a shift in the center of rotation toward the inner sinusoidal wall for lower-wavelength mixers. The mixing index is found to sensitively increase as the wavelength of the sinusoidal channel walls decreases over the entire Re range considered. A parametric study is also carried out with the amplitude, offset-y, and number of cycles as the geometrical parameters. Specifically, Re=1 and 30 are chosen to demarcate the effects of these parameters in terms of the mixing performance for diffusion- (Re≤1) and recirculation- (Re≥10) dominated regimes. The amplitude turns out to be an important parameter that significantly affects the mixing performance. The proposed sinusoidal micromixer shows much better mixing performance than square-wave and zigzag micromixers for the same wavelength. The proposed micromixer can easily be realized and integrated with microfluidic systems such as lab-on-a-chip and micro-total analysis systems (µ-TAS) because of its simple in-plane structure.
Micro-scale liquid droplets responding to depression between parallel plates are investigated analytically and numerically. The functional dependence of the reaction force accrued in such droplets on droplet size, surface tension, depression amount, and contact angle is explored. For both the 2D and 3D case, an analytical model is developed based on first principles. Computational fluid dynamics (CFD) is then utilized to evaluate the validity of these models. The reaction force is highly nonlinear, initially increasing very slowly with increasing depression of the droplet, but eventually moving asymptotically to infinity. Explicit expressions for the reaction force have been determined to estimate the maximum load of the droplet in the MEMS device at given contact angles and depression. The 3D model has been largely supported by the CFD results. It very accurately predicts the reaction force on the upper plate as the droplet is crushed, accounting for the effect of contact angle and depression rate.
The electro-deoxidation of unexfoliated GO has been carried out in aqueous solution. The electro-deoxidation of GO took place from −0.4 V vs. Ag/AgCl in KCl solution and showed the best results at −1.0 V. The pH value of the KCl solution after the electro-deoxidation increased up to 11.35 from the neutral electrolyte (pH=7.20) due to the build-up of OH− in the electrolyte, which originates from the oxygen functional groups removed from GO by the electro-deoxidation. The neutral solution was more effective than the alkali solution for the electro-deoxidation of GO.
With the aim of promoting bio-fuel production technologies, particularly those using bio-oil as a fuel for thermal power generation, we have developed a technique for bio-fuel extraction from Jatropha. The selective extraction of triglycerides from Jatropha seeds (a mixture of moisture, free fatty acids, and phosphorus) is required for developing new less-costly processes that avoid the oil refining treatment typically used in conventional technologies. The solubilities of Jatropha oil in super- and subcritical CO2 were measured, and the potential of CO2 to selectively extract triglycerides from Jatropha seeds by controlling the extraction time was revealed. The Jatropha oil extraction experiments were carried out under both super- and subcritical CO2 conditions using a flow-type apparatus. The amounts of Jatropha oil extracted by supercritical CO2from 35 to 50°C were a little bit larger than the amount by subcritical CO2 (25°C). Judging from the experimental data of the composition of the extract, subcritical CO2 has a potential to extract triglycerides from Jatropha seeds selectively by controlling the extraction time.