All issues
Volume 38 (2012)
- Issue 6 Pages 353-
- Issue 5 Pages 289-
- Issue 4 Pages 189-
- Issue 3 Pages 139-
- Issue 2 Pages 69-
- Issue 1 Pages 1-
Predecessor
Volume 38, Issue 6
Displaying 1-13 of 13 articles from this issue
- |<
- <
- 1
- >
- >|
Editorial Note
-
2012 Volume 38 Issue 6 Pages edit_6
Published: November 20, 2012
Released on J-STAGE: November 20, 2012
JOURNAL RESTRICTED ACCESSDownload PDF (185K)
Transport Phenomena and Fluid Engineering
-
Masao Aida, Atsushi ShonoArticle type: Research Papers
Subject area: Transport Phenomena and Fluid Engineering
2012 Volume 38 Issue 6 Pages 353-357
Published: November 20, 2012
Released on J-STAGE: November 20, 2012
JOURNAL RESTRICTED ACCESSBased on the experimental observation that the just-suspension speed is not affected by the baffle insertion depth, we proposed a new correlation method to estimate the Zwietering's geometrical constant S for solid suspensions in solid–liquid stirred vessels. The proposed equation is a function of power number under fully baffled condition NP,fbc, cb/D and d/D (cb, impeller off-bottom clearance; D, vessel diameter; d, impeller diameter). The geometrical constant for solid suspension estimated in this work agrees with the measured data reported in the literature. The just-suspension speed in solid–liquid stirred vessels with various types of impellers can be estimated by the proposed equation.View full abstractDownload PDF (612K)
Particle Engineering
-
Koji Masaoka, Masami HasegawaArticle type: Research Papers
Subject area: Particle Engineering
2012 Volume 38 Issue 6 Pages 358-364
Published: November 20, 2012
Released on J-STAGE: November 20, 2012
JOURNAL RESTRICTED ACCESSTo develop a method to simultaneously estimate the properties of salt (sodium chloride) products, namely, moisture content, mean particle size, and magnesium content, we conducted a basic test and a demonstration test. In the basic test, the relationships between these properties and the diffuse reflectance of salt products were examined on the basis of infrared diffuse reflectance of spectra recorded using a spectrophotometer. At all wavelengths, the diffuse reflectance of salt was found to change with changes in each property; and the degree to which each property contributes to changes in the diffuse reflectance depends upon the wavelength. Equations to predict the value of each property from the diffuse reflectance of multiple wavelengths were created from the relationships between each property and the spectrum data. Next, to create the optimum combination for simultaneous estimation, we selected the seven wavelengths that best average the prediction accuracies. In the demonstration test, the seven selected wavelengths were applied to a commercially available infrared analyzer. The effects of impurity content (other than magnesium) or any deviation in the mean particle size on the absorbance were found to be insignificant within the quality range of the manufactured salt product. Analytical curves that predict each property from the absorbance at the seven wavelengths were also created. These analytical curves showed good prediction accuracies.View full abstractDownload PDF (2947K) -
Kazumi Kozawa, Shunsuke Yamamoto, Takafumi Seto, Yoshio OtaniArticle type: Research Papers
Subject area: Particle Engineering
2012 Volume 38 Issue 6 Pages 365-371
Published: November 20, 2012
Released on J-STAGE: November 20, 2012
JOURNAL RESTRICTED ACCESSThe effect of a liquid dispersion aid on dry dispersion of submicron nickel powder was investigated. Measurements of test powder with and without added diethylene glycol monomethyl ether (DEG) revealed that addition of DEG improved the dispersability of nickel powder by a factor of about three. Observation of the structure of nickel powder indicated that the improvement is due to a change from compact agglomerates to chainlike agglomerates upon admixture of DEG. Since the dispersability of DEG-mixed nickel powder was unchanged after drying, the improvement may result from a reduction in coordination number between particles, rather than a decrease in bridging or adhesion force between particles.View full abstractDownload PDF (7960K)
Separation Engineering
-
Norihisa Mori, Naoyuki Kamishima, Shoji Okamoto, Hiroshi ShiwayaArticle type: Research Papers
Subject area: Separation Engineering
2012 Volume 38 Issue 6 Pages 372-377
Published: November 20, 2012
Released on J-STAGE: November 20, 2012
JOURNAL RESTRICTED ACCESSAir-conditioning systems in PWR nuclear power plants employ activated carbon filters to remove radioactive iodine compounds. Although the removal efficiency of radioactive iodine by activated carbon is very high, the total removal efficiency of iodine decreases if there is a bypass leak from a filter frame, gasket or elsewhere when the filters are attached to the unit. Thus, when the filters have been installed, it is necessary to ensure that the leak rate is below the tolerance level. The leak rate is determined by measuring the bypass leak of tracer gas that does not pass through the activated carbon bed. However, use of the conventional chlorofluorocarbon (R112) as tracer gas has now been abolished because of the accompanying risk of ozone depletion, so it is necessary to find an alternative reagent. Here, we report the results of a series of basic experiments to examine the applicability of alternative reagents.View full abstractDownload PDF (1625K) -
Daqi Cao, Eiji Iritani, Nobuyuki KatagiriArticle type: Notes
Subject area: Separation Engineering
2012 Volume 38 Issue 6 Pages 378-383
Published: November 20, 2012
Released on J-STAGE: November 20, 2012
JOURNAL RESTRICTED ACCESSDownward and upward membrane filtration experiments under constant pressure conditions were conducted for O/W emulsion using a dead-end filter, and filtration behaviors were compared. In downward filtration, the Ruth plot, in which the reciprocal filtration rate was plotted against the filtrate volume per unit membrane area, was obtained as an upward convex curve, while it showed a linear relationship in upward filtration in accordance with the Ruth filtration rate equation. In view of the difference in filtration behavior between the two filtration methods and the density contrast between the oil droplet and continuous phase, it was anticipated that the filter cake exfoliation occurred in downward filtration. The infinite average specific cake resistance was calculated from the experimental results of flux decline behaviors, assuming that the solid mass of filter cake increases in direct proportion to the filtrate volume. The specific resistance in downward filtration became smaller with the progress of filtration due to the exfoliation of filter cake. In contrast, the specific resistance in upward filtration remained virtually constant and was considerably larger than that in downward filtration. The value obtained in upward filtration was considered to be the true value that was uninfluenced by the exfoliation of filter cake. It was therefore concluded that the upward dead-end filtration test is quite effective for evaluation of filtration properties in membrane filtration of O/W emulsion.View full abstractDownload PDF (636K)
Thermal Engineering
-
Hyun-Seok Kim, Yohsuke Matsushita, Sohey Nozawa, Jin Miyawaki, Seong-H ...Article type: Research Papers
Subject area: Thermal Engineering
2012 Volume 38 Issue 6 Pages 384-390
Published: November 20, 2012
Released on J-STAGE: November 20, 2012
JOURNAL RESTRICTED ACCESSIn this study, the analytical solution of the mass transfer rate of oxidant to coal char particle surface with partial oxidation in an O2/N2 system was extended to that in an O2/CO2 system. The difference in the mass transfer mechanism of oxidant in the two systems was investigated by comparing the mass transfer rate of oxidant to char particle surface in these systems. As a result, the mass transfer rate of oxidant to char particle surface was found to be smaller in the O2/CO2 system than the O2/N2 system, corresponding to the diffusion coefficients when mass transfer is considered to occur by diffusion alone. The effect of convection due to the product of partial oxidation in the O2/CO2 system was found to be smaller in O2/N2 with an increase in volume fraction of oxidant. Therefore, the mass transfer rate of oxidant in O2/CO2 is greater than the difference in diffusion coefficient when both diffusion and convection due to the product of partial oxidation are taken into account. The model parameter in the analytical solution for mass transfer rate of oxidant with diffusion and convection due to the product of oxidation cannot be treated as constant in the O2/CO2 system and needs to be calculated according to volume fraction of oxidant, whereas it can be treated as constant in the O2/N2 system. The transition temperature from chemical reaction rate-controlling to mass transfer rate-controlling of oxidant is lower in the O2/CO2 system than the O2/N2 systemView full abstractDownload PDF (743K)
Chemical Reaction Engineering
-
Ikuo Ushiki, Masaki Ota, Yoshiyuki Sato, Hiroshi InomataArticle type: Research Papers
Subject area: Chemical Reaction Engineering
2012 Volume 38 Issue 6 Pages 391-396
Published: November 20, 2012
Released on J-STAGE: November 20, 2012
JOURNAL RESTRICTED ACCESSSurface modification of porous silica in supercritical carbon dioxide was studied using various alcohols as hydrophobizing reagents. The reaction was carried out using methanol, ethanol and 2-propanol at temperatures from 40 to 100°C, pressures from 8 to 20 MPa and reaction time from 0.5 to 6 h. The experimental results indicated that the surface modification occurred under all conditions, and methanol could provide the highest alkyl group density after modification among the three alcohols. Pressure and concentration dependence showed that the maximum density of alkyl group was obtained near the phase boundary condition for the carbon dioxide and methanol system. It was also suggested that hydrophobicity of the surface after modification was determined by density and size effects of alkyl group, which implied the existence of a threshold value of inversion from hydrophilicity to hydrophobicity.View full abstractDownload PDF (1517K) -
Taiki Hiramatsu, Hoda Montazeri Najafabadi, Nobusuke Kobayashi, Yoshin ...Article type: Research Papers
Subject area: Chemical Reaction Engineering
2012 Volume 38 Issue 6 Pages 397-402
Published: November 20, 2012
Released on J-STAGE: November 20, 2012
JOURNAL RESTRICTED ACCESSNon-equilibrium plasma was found to be induced at atmospheric pressure by low-power microwave irradiation of an argon gas stream in a packed bed of activated coke. The effect of microwave power and the presence of N2 on the behavior of this plasma generation were studied. Plasma density was drastically enhanced over a certain microwave power, but the presence of N2 could have an inhibitory effect. When the plasma was applied to decomposition of NO contained in argon, sufficiently high conversion of NOx reduction was obtained in the absence of a catalyst or reducing agent. Conversion of NOx reduction was improved only slightly by injection of NH3 as a reducing agent.View full abstractDownload PDF (1525K) -
Ryoko Nakano, Eiko Obuchi, Katsumi Katoh, Katsuyuki NakanoArticle type: Research Papers
Subject area: Chemical Reaction Engineering
2012 Volume 38 Issue 6 Pages 403-407
Published: November 20, 2012
Released on J-STAGE: November 20, 2012
JOURNAL RESTRICTED ACCESSThe effect of the support on photocatalytic degradation activity was investigated with three kinds of catalyst beads (TiO2/SiO2, TiO2/Al2O3 and TiO2/Zeolite) using phenol as a reactant. The rate constant of phenol degradation and the conversion to inorganic carbon were compared among three kinds of catalysts. The rate constant (k) for TiO2/Al2O3 was the largest (0.0448 min−1) followed by TiO2/SiO2 and TiO2/Zeolite at 0.0246 and 0.0235 min−1, respectively. The conversion to inorganic carbon after 120 min UV irradiation was the lowest for TiO2/Zeolite (22.4%) among three catalysts. Thus, the influence on the reaction mechanism of different supports was discussed from the time courses of concentration in phenol, intermediate products and also the amount of TOC changed to inorganic carbon. Based on the HPLC species analysis, the photocatalytic degradation mechanism was suggested to involve consecutive reactions. In addition, the pH value in the solution depended on the support used, i.e., around 6 for TiO2/SiO2 and TiO2/Al2O3, and around 7 for TiO2/Zeolite. GC/MS analyses showed that negatively charged compounds were produced in the reaction on TiO2/Zeolite Since the ζ-potential on the catalyst surface is considered to depend on the pH of the solution, adsorption of the charged compounds on the catalyst surface would be inhibited by an electrostatic effect. This phenomenon will affect the photocatalytic degradation activity of phenol on each catalyst.View full abstractDownload PDF (1497K)
Process Systems Engineering and Safety
-
Makoto Kato, Masaru Noda, Kazuhiro Takeda, Yasunori Kikuchi, Masahiko ...Article type: Research Papers
Subject area: Process Systems Engineering and Safety
2012 Volume 38 Issue 6 Pages 408-414
Published: November 20, 2012
Released on J-STAGE: November 20, 2012
JOURNAL RESTRICTED ACCESSWe propose a new design method for alarm systems, in which we assume that the pattern and the sequence of alarms generated by the alarm system are invariant for each possible malfunction. Operators can find the root causes of malfunctions not only from the patterns of generated alarms but also from their sequences, which means that the proposed method can identify more malfunctions than the previous one. Theoretical analysis showed that our method is especially effective for isolating the root causes of malfunctions that have corresponding nodes in the connected cause-effect graph. The proposed method was applied to the design of an alarm system for a basic chemical plant. The proposed method enables users to determine the maximum number of identifiable malfunctions, which clearly demonstrates its usefulness in the design of alarm systems.View full abstractDownload PDF (359K)
Engineering Education
-
Norihiro Kose, Tsuguhiko Nakagawa, Koichi ShinoharaArticle type: Research Papers
Subject area: Engineering Education
2012 Volume 38 Issue 6 Pages 415-423
Published: November 20, 2012
Released on J-STAGE: November 20, 2012
JOURNAL RESTRICTED ACCESSIn order to introduce and expand the use of natural energy, research has recently been conducted on smart communities that manage the energy balance in a specific region.
For a system combining photovoltaic power generation (PV) and electric vehicles (EV), we have developed a model to quantitatively evaluate the change in energy use by EV together with other energy in a specific region with multiple EV. Using this model, we have examined a method to optimize PV use in the case of conversion to EV use based on data of actual vehicle movement.
As a result, for designing a combined system PV and EV, we have defined two new indexes: PV rate of electric consumption by EV, and EV usage rate of PV. By using the new indexes, we have shown that it is possible to design the installation site, scale of PV and battery capacity of EV according to the use of EV.View full abstractDownload PDF (1797K)
Environment
-
Junji Shibata, Norihiro Murayama, Toru KosekiArticle type: Research Papers
Subject area: Environment
2012 Volume 38 Issue 6 Pages 424-430
Published: November 20, 2012
Released on J-STAGE: November 20, 2012
JOURNAL RESTRICTED ACCESSWhen V and Ni in crude oil are adsorbed on the surface of a desulfurization catalyst composed of MoS2, Co and Ni supported on Al2O3, the catalyst loses its catalytic activity. To recover Mo and V from the spent catalyst, soda roasting at high temperature and alkali leaching are applied industrially, but Ni and Co cannot be recovered by this process. The present study aimed to develop an environmentally friendly process to separate and recover all of these rare metals from the spent oil desulfurization catalyst at low temperature. Through a process consisting of leaching of the spent catalyst with the dilute sulfuric acid and hydrochloric acid, followed by separation with solvent extraction and crystallization-stripping, the rare metals were recovered as CaMoO4, NH4VO3, NiC2O4 and CoC2O4.View full abstractDownload PDF (1029K)
- |<
- <
- 1
- >
- >|