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Volume 43, Issue 12
Displaying 1-9 of 9 articles from this issue
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Separation Engineering
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Fitriani, Takao KokuganArticle type: Research Paper
Subject area: Separation Engineering
2010 Volume 43 Issue 12 Pages 983-992
Published: December 20, 2010
Released on J-STAGE: December 20, 2010
Advance online publication: August 17, 2010JOURNAL RESTRICTED ACCESSThe cross-flow filtration characteristics of bacterial cells (S. bovis) obtained from a lactic acid fermentation broth of fresh cassava roots have been investigated in terms of specific cake resistance. The amount of particles accumulated on the membrane surface was evaluated using a cake filtration model. The effects of the operating conditions (transmembrane pressure, cross-flow velocity and cell concentration) on permeate flux, cake resistance and specific cake resistance were studied. The cake properties in cross-flow filtration were then compared to those in dead-end filtration. The specific cake resistance in the cross-flow filtration shows a higher value than in the dead-end filtration for almost the same cake compressibilities of about 1.0. The specific cake resistance increases with increasing cross-flow velocity and decreases with increasing cell concentration until reaching a concentration at which the specific cake resistance hardly changes. The increasing ratio of the specific cake resistance in the cross-flow filtration over the dead-end filtration is found to be independent of the transmembrane pressure and cell concentration.View full abstractDownload PDF (865K) -
Fitriani, Yoshiyuki Yamashita, Takao KokuganArticle type: Short Communication
Subject area: Separation Engineering
2010 Volume 43 Issue 12 Pages 993-997
Published: December 20, 2010
Released on J-STAGE: December 20, 2010
Advance online publication: August 18, 2010JOURNAL RESTRICTED ACCESSAn unsteady-state model for cross-flow microfiltration of lactic acid fermentation broth is presented in this manuscript. Compared with earlier models, the improved model can calculate specific cake resistance and membrane fouling resistance simultaneously. Filtration properties are obtained by solving the model with numerical integration and optimization. The model has been used for the analysis of experimental data and the results show good agreement with the experimental permeate flux. The model predicts smaller specific cake resistance by taking into account the membrane fouling resistance.View full abstractDownload PDF (853K)
Chemical Reaction Engineering
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Jian Chen, Yu Guo, Lu Zhou, Huabo Li, Wen Zhao, Makoto Sakurai, Hideo ...Article type: Research Paper
Subject area: Chemical Reaction Engineering
2010 Volume 43 Issue 12 Pages 998-1007
Published: December 20, 2010
Released on J-STAGE: December 20, 2010
JOURNAL RESTRICTED ACCESSA series of anodic-alumina-supported silver catalysts (Ag/Al2O3) were synthesized to investigate the promotional effect of H2 and electrical heating possibility on the selective catalytic reduction (SCR) of NO by C3H6.
It was observed that the SCR activity of Ag/Al2O3 catalyst was greatly improved at low temperatures in the presence of H2. Moreover, this promotional effect became more significant with increasing H2 concentration. According to the results of the reaction without C3H6, H2 did not significantly improve the activity; this indicates that the H2 acted as a promoter but did not directly participate in NOx reduction. The results of NOx-TPD (Temperature Programmed Desorption) and NOx-H2-TPR (Temperature Programmed Reduction) showed that the NOx adsorbed on the catalyst surface was quickly desorbed in the presence of H2, while NOx desorption became faster by increasing the concentration of H2 added to the flow as well as the Ag loadings. In the case of catalysts with low Ag loadings, nitrate poisoning was considered to be the main reason for low NOx conversion at low temperatures. On the other hand, in the case of the high Ag loadings, the scarcity of Agnδ+ clusters was inferred to result in unfavorable SCR activity.
Additionally, electrical heating tests on the SCR by C3H6 in the presence of Ag/Al2O3 catalysts showed excellent denitration activity and rapid reaction rate. On the basis of the electrical heating pattern, a new strategy for controlling NOx emission from diesel engines was formulated.View full abstractDownload PDF (2161K) -
Yoshiyuki Asakura, Satoshi Fukutomi, Keiji Yasuda, Shinobu KodaArticle type: Research Paper
Subject area: Chemical Reaction Engineering
2010 Volume 43 Issue 12 Pages 1008-1013
Published: December 20, 2010
Released on J-STAGE: December 20, 2010
Advance online publication: September 17, 2010JOURNAL RESTRICTED ACCESSFor any sonochemical process, the maximum effect depends on a range of conditions and process optimization can lead to a considerable savings in electric power. In this paper, the optimization investigation focuses on the acoustic features of the ultrasonic reactor, such as the transducer impedance and the frequency components of sound pressure with respect to the reactor configuration, namely the liquid height and the upper end configuration for a cylindrically shaped sonochemical reactor. Measurements were carried out for the liquid heights varying in the range of 142 to 163 mm with and without an aluminum reflector mounted on the upper end of the liquid column for a ultrasonic frequency of 129 kHz. Our data revealed that the impedance of the transducer and the sonochemical efficiency are strongly dependent on the liquid height and on the upper part configuration of the reactor: free or fixed end. Moreover, the maximum sonochemical efficiency was attained at liquid heights where the transducer impedance showed minimum values, the distance between two consecutive maxima being λ/2 (where λ=11.6 mm in this work). The frequency components of the sound pressure into the liquid were also investigated, and it was discovered that the maximum sonochemical efficiency was reached when the harmonic components were enhanced and subharmonic were reduced. An automatic control system for increasing the sonochemical efficiency by maintaining the impedance at the minimum level with the help of frequency is presented here.View full abstractDownload PDF (1014K) -
Ireneusz GrubeckiArticle type: Short Communication
Subject area: Chemical Reaction Engineering
2010 Volume 43 Issue 12 Pages 1014-1019
Published: December 20, 2010
Released on J-STAGE: December 20, 2010
JOURNAL RESTRICTED ACCESSA process with a power-law model of reaction running in a batch reactor in the presence of catalyst undergoing parallel deactivation has been analyzed. On the basis of the method of variational calculus, a analytical determination aiming at the choice of the optimal temperature condition has been carried out. The advantages resulting from the application to choose the optimal temperature profile with respect to the isothermal conditions in terms of the duration time of the process have been assessed. The effects of the selected kinetic parameter on the magnitude of the above mentioned advantages has also been considered and compared with that obtained for a reaction with deactivation independent of substrate concentration.View full abstractDownload PDF (673K)
Biochemical, Food and Medical Engineering
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Hiroshi Tabata, Ken Tsutsumi, Yoichi Matsushita, Aya Nishiwaki, Sachio ...Article type: Short Communication
Subject area: Biochemical, Food and Medical Engineering
2010 Volume 43 Issue 12 Pages 1020-1022
Published: December 20, 2010
Released on J-STAGE: December 20, 2010
Advance online publication: September 29, 2010JOURNAL RESTRICTED ACCESSEnhancement of enzymatic saccharification of lignified stalks of Kudzu (Pueraria lobata) was examined. The yield of enzymatically hydrolyzed glucose obtained from alkaline pretreated ligneous kudzu stalks with 1.0% NaOH solution at 373 K for 1 h was 48% of cellulose included. The enhancement of amount of obtained glucose from the alkaline pretreated kudzu stalks was examined using silicon under visible light irradiation at room temperature. Hydrogen evolved continuously during irradiation. The quantity of obtained glucose increased up to ca. 1.5 times large value after the treatment with silicon for 2 h, and the yield of glucose was 70% after enzymatic saccharification for 72 h.View full abstractDownload PDF (919K)
Micro and Nano Systems
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Erika Katayama, Shigenori Togashi, Yoshishige EndoArticle type: Research Paper
Subject area: Micro and Nano Systems
2010 Volume 43 Issue 12 Pages 1023-1028
Published: December 20, 2010
Released on J-STAGE: December 20, 2010
Advance online publication: August 20, 2010JOURNAL RESTRICTED ACCESSWe have developed a microreactor system for the continuous producting of nanoparticles, and we have clarified the relationship between the mixing performance of reactors and the particle size. First, we evaluated the mixing performance of reactors by carring out the Villermaux–Dushman reaction and determined the experimental conditions for producing AgCl nanoparticles. Next, we developed the microreactor system by including a pressure sensor and an ultrasonic generator in order to prevent the clogging of nanoparticles. Finally, we produced AgCl nanoparticles and evaluated the mixing performance and the particle size. The operating time of the new system was long. Moreover, we found that as the mixing performance improves the size of produced particles decreases and the particle size distribution becomes sharper. We produced AgCl nanoparticles with a size of 86 nm using the microreactor that had the best mixing performance among the three reactors we tested in this study; the coefficient of variation (Cv) of the size distribution of the produced nanoparticles was 26.1%.View full abstractDownload PDF (5351K)
Energy
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Xiao-Yan Zhao, Jing-Pei Cao, Kazuyoshi Sato, Yukiko Ogawa, Takayuki Ta ...Article type: Research Paper
Subject area: Energy
2010 Volume 43 Issue 12 Pages 1029-1034
Published: December 20, 2010
Released on J-STAGE: December 20, 2010
Advance online publication: September 07, 2010JOURNAL RESTRICTED ACCESSHigh surface area activated carbons (ACs) were prepared by chemical activation of black liquor with potassium hydroxide. The influence of carbonization temperature, activation temperature and impregnation ratio of activating agent to char on the porous characteristics of the ACs was investigated. The results show that the surface area and pore volume of ACs, which were estimated by BET methods, were achieved as high as 3089.2 m2 g−1 and 1.7595 cm3 g−1 under the condition of an carbonization temperature of 600°C, an activation temperature of 900°C, and an impregnation ratio of 2. In addition, the influence of alkali metals (sodium and potassium) existing in black liquor on activation was also examined. It was found that the alkali metals react as an activating agent in the process of activation, thereby economizing the amount of activating agent used in this study to a high degree.View full abstractDownload PDF (855K)
Engineering Education
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Brian G. Higgins, Housam BinousArticle type: Short Communication
Subject area: Engineering Education
2010 Volume 43 Issue 12 Pages 1035-1042
Published: December 20, 2010
Released on J-STAGE: December 20, 2010
Advance online publication: September 17, 2010JOURNAL RESTRICTED ACCESSWe describe a simple method for tracking solutions of nonlinear equations f(u,α) = 0 through turning points (also known as limit or saddle-node bifurcation points). Our implementation makes use of symbolic software such as Mathematica to derive an exact system of nonlinear ODE equations to follow the solution path, using a parameterization closely related to arc length. We illustrate our method with examples taken from the engineering literature, including examples that involve nonlinear boundary value problems that have been discretized by finite difference methods. Since the code requirement to implement the method is modest, we believe the method is ideal for demonstrating continuation methods in the classroom.View full abstractDownload PDF (695K)
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