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)) Shin Mukai (Hokkaido University) Akinori Muto (Osaka Prefecture University) Nobuyoshi Nakagawa (Gunma University) Hiroyasu Ogino (Osaka Prefecture University) Naoto Ohmura (Kobe University) Mitsuhiro Ohta (Muroran Institute of Technology) Hiroshi Ooshima (Osaka City University) 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) 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))
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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
Outstanding Paper Awards Subcommittee of Journal of Chemical Engineering of Japan has assessed the 147 papers published in volume 43 into 2010, and the editorial board finally selected the four papers for JCEJ Outstanding Paper Awards of 2010; those are the papers on “Application of a Microreactor in the Oxidative Dehydrogenation of Propane to Propylene on Calcium Hydroxyapatite and Magnesium ortho-Vanadate Doped and Undoped with Palladium,” “On-Line Property Prediction for Industrial Slurry High-Density Polyethylene Processes with Various Grade Transition Modes,” “Development of Dimethyl Ether Production Process Based on Biomass Gasification by Using Mixed-Integer Nonlinear Programming,” and “Direct Simulation Model of Concentrated Particulate Flow in Pressure-Driven Dead-End Microfiltration.”
A method for estimating Wilson parameters on the basis of solubility parameters and molar volumes has been adopted to correlate vapor–liquid equilibria of polar mixtures such as binary systems containing ethers, ketones, ethanol, and water. The correlation performances are examined and discussed.
In the present study, La0.7Sr0.3Co0.5Fe0.5O3-δ powders have been prepared by thermal decomposition of amorphous citrate precursors by calcination at high temperature. The material properties are characterized by thermogravimetric-differential thermal analysis, X-ray diffraction, and four probe method. A perovskite structure with rhombohedral symmetry has been certified for the selected La0.7Sr0.3Co0.5Fe0.5O3-δ oxide membranes. The electrical conductivity of sintered La0.7Sr0.3Co0.5Fe0.5O3-δ ceramics increases with temperature through a maximum, then decreases at relatively higher temperatures, due to oxygen vacancy formation. Oxygen permeation was performed between 700 and 950°C under different oxygen partial pressures (0.21, 0.42, and 0.63 atm) and carbon dioxide concentrations (300, 500, and 700 ppm). According to Arrhenius' law, the oxygen permeation flux of the membranes with a thickness of 1.1 mm increases with temperature and oxygen partial pressure. A maximum oxygen flux of ~0.33 mL/min · cm2 and ~0.25 mL/cm2 · min was measured at 950°C at high oxygen pressure (PO2 = 0.63 atm) and under carbon dioxide concentration range from 300 to 700 ppm, respectively.
Microfiltration membranes of poly(L-lactic acid) (PLLA), which is a major biodegradable plastic, were prepared from PLLA–1,4-dioxane–water solutions via the thermally induced phase separation. The resulting membranes are used to retain bacterial cells and permeate protein molecules. Only 20% of the bacterial cells in cell suspensions were retained by the membranes prepared from 10–12.5% polymer solution. Increasing the polymer concentration from 12.5 to 15% markedly elevated the bacterial cell retention to 60%. The retention further increased to 90% by elevating the casting temperature from 40 to 50°C. By drying the polymer solution for 2 min before quenching, the cell retention reached 99%. Casting at temperatures of 60°C or higher and drying for periods of 5 min or longer made the membrane uneven and/or increased the membrane resistance. By drying the polymer solution before quenching, the porous structure near the membrane surface was altered so that the membrane retains the bacterial cells. The membrane retained bacterial cells in the manner of a screen filter. The membranes developed in this research will be useful as a pre-filter in biochemical processes to enhance the life time of the final filters and to reduce industrial wastes due to being made of a compostable polymer.
The fouling potential of a colloidal silica suspension as the feed phase at varied solution chemistry has been investigated using negatively charged polyamide thin-film-composite nanofiltration (NF) membranes. Specifically, the effects of solution chemistry, feed pH and ionic strength, and colloidal particle size on the fouling potential measurement have been investigated. The effect of pH on the measurement of the fouling potential is different for different membranes. An alkaline feed solution pH is preferred because of its minimal tendency to foul the membranes. Colloidal size does not have a remarkable effect on the fouling potential measurement for the size range studied herein (about 10 nm), but larger particles result in less fouling, as observed normally. Ionic strength also plays an important role in the fouling of silica colloid suspensions, with lower ionic strength resulting less fouling.
The objective of this study was to convert heptylbenzene (HPB), the simplest model compound of heavy oils, into low-molecular-weight hydrocarbons by suppressing side reactions that produced high-molecular-weight compounds and char. The dramatic variability in the ion product and the dielectric constant of water under supercritical conditions rendered supercritical water (SCW) an acid or a base catalyst. In this study, water was used without any catalyst. The reaction was carried out in an 8.8-mL batch reactor fabricated from Hastelloy C-276. The ability of SCW to decompose HPB was studied at temperatures ranging from 425 to 475°C and pressures from 30 to 40 MPa. HPB was converted into light hydrocarbons such as ethylbenzene, propylbenzene, and butylbenzene, as well as heavy hydrocarbons and gases under the abovementioned conditions. The major liquids produced were toluene, ethylbenzene, unbranched phenylalkanes, branched phenylalkanes, phenylolefins, benzene, and naphthalene. HPB thermolysis followed first-order kinetics, with the following Arrhenius parameters: activation energy, 26.37±1.21 kcal/mol; log(A, s−1), 10.81±0.50, where A is the pre-exponential factor. HPB pyrolysis in SCW followed almost identical kinetics, and SCW had negligible influence on the reaction path. A low water partial pressure was favorable for reducing the formation of heavier compounds, although the overall HPB conversion was close to 88% at a temperature of 450°C and a reaction time of 60 min. Char formation was drastically reduced in the SCW environment. These results suggested that water acts as a chemical reagent above its critical point (374°C and 22.1 MPa) and aids HPB decomposition.
We propose a quality classification methodology based on optimal textural feature selection. This method employs the wavelet packet transform to decompose the original image into multiple-resolution images. Wavelet texture analysis is applied to extract quality-related features from subimages. Optimal textural feature selection is employed to select the discriminative texture in accordance with class information. The previously used best basis approach is incapable of optimal texture classification when combined with wavelet texture analysis. The proposed texture classification method unifies the best basis approach with wavelet texture analysis. Further, we improve the previous best basis to obtain an optimal basis using a simple rule to select discriminative signatures. The proposed methodology is applied and validated for classifying the surface quality of rolled steel sheets. Experimental results show that features extracted using the proposed method are more discriminative than those obtained using the best basis in terms of classification performance and Fisher's index.
The objective of this study is to develop the process conditions of a w/o emulsification method for the preparation of the smallest agar nanoparticles possible in a low nanometer range with the highest yield, prior to adding an aqueous solution containing an unstable drug such as a protein drug for its encapsulation. The volume ratio between the organic phase and aqueous phase was set as 10 : 1, the lowest ratio among those of previous investigations. Agar solutions of 0.5, 1 and 2%w/v concentration were emulsified in soybean oil. Then, various homogenizer speeds were investigated for the yield of agar nanoparticles and their particle size distribution under those agar concentrations. The visual appearance of the re-dispersed emulsion-converted-to suspension was turbid without any visible aggregates, even though the suggested methodology is more economically efficient in terms of the ratio between the organic phase and aqueous phase, than those of previous investigations. In terms of agar concentration, the yields of agar nanoparticles were optimized at 1%w/v of agar concentration for all the homogenizer speeds of 13000, 15000 and 17000 rpm. Accordingly, the yield of 76.5% was the highest at the preparation conditions of 1%w/v agar concentration and 15000 rpm homogenizer speed.
In recent years, microfluidic devices have been frequently used to handle highly concentrated solutions. In these cases, the influence of the viscosity of the solution on the flow and diffusion in the microfluidic device cannot be neglected. In this study, the hydrodynamic and diffusion behaviors of two liquids having different viscosities in contact in a double-Y-type microfluidic device were investigated. The relationship between the concentration and the flow rate at the outlet of the microfluidic device and the ratio of viscosities of the solution and the solvent was determined. Computational fluid dynamics (CFD) was used to predict the flow in the microfluidic device. The diffusion of a Co2+-DEHPA complex in the microfluidic device was also investigated. When two fluids with different viscosities were pumped into the channel at the same flow rate, the high-viscosity fluid flowed to the low-viscosity side. The cross section of the low-viscosity fluid became narrow, the velocity increased, and the interface between the two fluids moved to the low-viscosity fluid side. When the viscosity ratio was large, the interface shift and velocity difference were large. The numerical simulation performed reproduced the influence of the viscosity ratio on the velocity and concentration distribution. The movement of the interface could be prevented by increasing the relative flow rate the of low-viscosity fluid, and this was also reproduced by the numerical simulation.
Ordered mesoporous carbons (COU-1 and COU-2) were synthesized using a soft-templating method. Then, COU-1 and COU-2 were activated using KOH to improve their porosity. Galvanic charge-discharge cycles were employed to investigate the electric double-layer capacitance of the ordered mesoporous carbons in an aqueous electrolyte. The contributions of the surface areas of the ultramicropores (d < 0.7 nm) and micro- and mesopores (d > 0.7 nm) to the capacitance were evaluated using a simple model. The ultramicropore surface area hardly contributed to the capacitance. On the other hand, the surface area of the larger pores (d > 0.7 nm) strongly contributed to the capacitance, suggesting that pores larger than 0.7 nm are necessary for the fast diffusion of sulfate ions to the pore surface. The capacitance of the ordered mesoporous carbons was higher than that of disordered mesoporous carbon, probably because of the micropores in the uniform thin pore walls and regularly interconnected uniform mesopores in the former case.
Stability and sensitivity of the curtain drawing flow have been investigated by employing the simplified one-dimensional viscocapillary model. A time-dependent model has been derived using the lubrication approximation and integral momentum balance approach of two-dimensional curvilinear Navier–Stokes equations. Process stability and sensitivity have been examined by considering linear stability and frequency response methods for a linearized curtain system, respectively. Among the process conditions affecting the curtain dynamics, the effect of air pressure difference across the curtain has been mainly focused upon. It is shown that the air pressure difference makes the system less stable and more sensitive to disturbances, leading to curtain deflection and a slightly longer trajectory.
Transesterification is affected by the free fatty acid (FFA) content of vegetable oils or animal fats. A two-step H2SO4/CaO-catalyzed methanolysis process has been employed for the efficient conversion of Jatropha curcas crude oil, which has an acid value greater than 30 mg KOH/g, into fatty acid methyl ester (FAME). The effects of H2SO4 catalyst addition, of FFA, and of the water produced as a by-product are investigated. The maximum esterification activity of the initial FFA content are obtained with 0.5–1.2 wt% H2SO4 relative to Jatropha crude oil. The esterification product is used as the substrate for a second, CaO-catalyzed, transesterification. Water usually has an adverse effect on transesterification; however, this study proves that the effect of water is negligible. Using this two-step methanolysis reaction, a FAME level greater than 96% can be obtained in the final product.