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Volume 35 (2009)
- Issue 6 Pages 573-
- Issue 5 Pages 417-
- Issue 4 Pages 337-
- Issue 3 Pages 265-
- Issue 2 Pages 195-
- Issue 1 Pages 1-
Predecessor
Volume 35, Issue 3
Displaying 1-11 of 11 articles from this issue
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Transport Phenomena and Fluid Engineering
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Yoshiro Inoue, Dai Takaoka, Buntaro Okada, Kazunari Natami, Shunsuke H ...Article type: Research Paper
Subject area: Transport Phenomena and Fluid Engineering
2009 Volume 35 Issue 3 Pages 265-273
Published: May 20, 2009
Released on J-STAGE: May 27, 2009
JOURNAL RESTRICTED ACCESSThe flow system in an agitated vessel is extremely complex because it is time-dependent, three-dimensional and spatially unsymmetric. Therefore, many questions on the mechanism of fluid mixing remain unsolved. In two-dimensional laminar mixing caused by chaotic flow, stable and unstable manifolds play important roles in the analysis of the fluid mixing. These invariant manifolds make the invariant structure controlling the mechanism of fluid mixing and act as the template of the mixing pattern. However, we do not know whether a similar invariant structure also exists in three-dimensional flow systems. In this study, we analyzed the mechanism of laminar fluid mixing in a three-dimensional agitated vessel with a two-blade paddle impeller, focusing on the particular streakline that grows from the tip of a blade and acts like an unstable manifold. On the basis of a visualizing experiment and numerical simulation with a simple flow model, we showed that this streakline is closely concerned with the formation of mixing pattern, and its strong stretching and folding near the side wall of the agitated vessel give rise to laminar global fluid mixing.View full abstractDownload PDF (5928K)
Particle Engineering
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Mikio Yoshida, Shingo Nakatsukasa, Kuniaki Gotoh, Tatsuya Zushi, Yasuo ...Article type: Research Paper
Subject area: Particle Engineering
2009 Volume 35 Issue 3 Pages 274-278
Published: May 20, 2009
Released on J-STAGE: May 27, 2009
JOURNAL RESTRICTED ACCESSA semi-continuous gas-solid fluidized bed separator was newly developed in order to achieve efficient separation of objects with different true specific gravities. A pilot-scale experimental apparatus with variable feeding height of objects was operated. Sand with minimum fluidization velocity of 3.5 cm/s was employed as bed material. Separation of chlorine-free plastics from a mixture of waste plastics containing chlorine-containing plastics was attempted. As a simulated waste plastics mixture, a mixture of Cl-free plastic pellets and Cl-containing plastic pellets was employed. When the plastic mixture was fed at the middle of the bed, the separation time was shortest and separation efficiency was highest. Also, the effect of initial mixture loading on the separation efficiency was evaluated.View full abstractDownload PDF (5232K) -
Keiji Tsubota, Yuki Masuda, Eisuke Yamaguchi, Hironobu Imakoma, Naoto ...Article type: Research Paper
Subject area: Particle Engineering
2009 Volume 35 Issue 3 Pages 279-281
Published: May 20, 2009
Released on J-STAGE: May 27, 2009
JOURNAL RESTRICTED ACCESSThe effects of microwave irradiation on drying rate and mechanical strength of a particle layer solidified by drying were examined for a packed-bed sample of glass particles wetted with gelatin solution as a model of casting mould manufacture. Overall drying time was remarkably shortened by microwave irradiation in comparison with convective drying alone. Mechanical strength of the dried sample depended only on temperature during drying for samples with mean moisture content of 0.01–0.02 kg-water/kg-dry solid, suggesting that the main effect of microwave irradiation on solidification by drying is brought about by a temperature increase in the material.View full abstractDownload PDF (324K)
Separation Engineering
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Issei FujiyoshiArticle type: Research Paper
Subject area: Separation Engineering
2009 Volume 35 Issue 3 Pages 282-286
Published: May 20, 2009
Released on J-STAGE: May 27, 2009
JOURNAL RESTRICTED ACCESSThe adsorption experiment of divalent transition metals, such as cobalt, nickel, copper and zinc on porous glass from ethylenediamine aqueous solution was carried out at 298 K. The comparison between the experimental values of amount of metal adsorbed and the formation curves of ethylenediamine-metal complex ions suggested that adsorption mechanism was coordination reaction, because adsorption of metal was accelerated with formation of ethylenediamine complex ion in the case of nickel, copper and zinc. The contribution of ion-exchange to adsorbed amount was negligibly small comparing with coordination reaction. It seemed that trivalent cobalt ion was formed by the oxidation in exchanging mother solution, then it was adsorbed by ion exchange for adsorption of cobalt.
The separation experiment of the metals mentioned above was carried out by the porous glass packed column using ethylenediamine as an eluent at 298 K. The retention times of these metals were increased with amount of metal adsorbed in all cases. Cobalt, nickel and copper were eluted by this order and almost completely separated in the range of ethylenediamine concentration less than 0.2 mol/dm3, when the eluent was used at pH 6.0. In this case zinc was not isocratically eluted, because zinc was adsorbed much than three other metals.View full abstractDownload PDF (314K)
Chemical Reaction Engineering
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Yasushi Sugawara, Katsuyasu Sugawara, Takuo SugawaraArticle type: Research Paper
Subject area: Chemical Reaction Engineering
2009 Volume 35 Issue 3 Pages 287-292
Published: May 20, 2009
Released on J-STAGE: May 27, 2009
JOURNAL RESTRICTED ACCESSEffect of light intensity was kinetically investigated on the catalytic inactivation of aerobic bacteria, with a laminated photocatalyst prepared by drying a commercial titanium-dioxide emulsion on the stainless-steel plate, in the solution discharged and filtered with diatomite filter-aids from a soaking process of brown rice germination under the blacklight-lamp irradiation.
The inactivation under 352 nm light irradiation was enhanced with shorter induction periods as the number of lamps increased.
In terms of effective light intensity Ieff and microorganism concentration C which could control the process, the inactivation rate was successfully represented by the following equation with a shorter induction period,
-dC/dt=k·Ieff·C
where Ieff was defined the light intensity effective to the inactivation of microorganism through active species produced on the photocatalyst surface under illuminated light intensity I. The absolute value of Ieff was considered a function of radiant light intensity I0 (r2), solution thickness l, and light absorptivity of solution μ; the reference value was selected to be the illuminated light intensity I calculated with a set of minimum values of r2 and l: r2=2.5×10−3 m, l=1.0×10−3 m under the defined number of lamps.
With increasing the radiant light intensity I0, the absolute value of effective light intensity Ieff got larger and the ratio of effective light intensity to illuminated light intensity Ieff/I was nearly the same.View full abstractDownload PDF (415K) -
Hideo Nagata, Norihito Kita, Haruki MoriArticle type: Research Paper
Subject area: Chemical Reaction Engineering
2009 Volume 35 Issue 3 Pages 293-296
Published: May 20, 2009
Released on J-STAGE: May 27, 2009
JOURNAL RESTRICTED ACCESSThe hydrolysis of dichlorodifluoromethane (CFC-12) was investigated using alumina-zirconia catalysts, which exhibited high performance during the oxidative decomposition of chloropentafluoroethane (CFC-115) in the presence of butane. The CFC-12 conversion increased during the hydrolysis of CFC-12 over alumina-zirconia catalysts. X-ray diffraction patterns and temperature-programmed desorption profiles of ammonia revealed the formation of a new acid site induced by the halogen atoms and water vapor formed during hydrolysis.View full abstractDownload PDF (287K)
Materials Engineering and Interfacial Phenomena
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Takehiro Yamamoto, Eiji Aizawa, Hironobu Imakoma, Yoshiyuki Komoda, Na ...Article type: Research Paper
Subject area: Materials Engineering and Interfacial Phenomena
2009 Volume 35 Issue 3 Pages 297-303
Published: May 20, 2009
Released on J-STAGE: May 27, 2009
JOURNAL RESTRICTED ACCESSA slurry sample was prepared by dispersing spherical micro-particles of poly(methyl methacrylate) (PMMA) in aqueous solution of polyvinyl alcohol (PVA), and a coated film sample was prepared by applying the slurry sample on a polyester sheet. The drying rate of the film sample was measured by a modified temperature change method. The effect on the drying rate of micro-particle concentration, defined as micro-particle volume/dried polymer volume, was examined in the range from 0.25 to 1.0, in which the porosity of the dried film was expected to be zero, and the effect of the micro-particle radius was also examined.
During the period of decreasing drying rate, the drying rate was found to decrease with increasing micro-particle concentration and with decreasing micro-particle radius. Subsequently, the drying rate was almost constant, and the porosity was almost zero. The constant drying rate observed during the latter period was explained by a mass transfer model incorporating drying stress proposed by the authors in this study.
The gloss on the surface of dried film was also measured and found to decrease with increasing micro-particle concentration, but to be little affected by the particle radius.View full abstractDownload PDF (1217K)
Energy
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Hideki Itou, Shigeru Tsurumaki, Takuya Moriga, Akihiko Yamada, Shigeru ...Article type: Research Paper
Subject area: Energy
2009 Volume 35 Issue 3 Pages 304-311
Published: May 20, 2009
Released on J-STAGE: May 27, 2009
JOURNAL RESTRICTED ACCESSWhat a polymer electrolyte fuel cell (PEFC) stack consisting of nine cells was operated under low humidification for 2000 h, polymer membrane breakage was found in three of the nine cells. This breakage was found to be caused by chemical deterioration by an OCV accelerated durability test; and the mechanism of deterioration was estimated to be decomposition of the membrane by hydrogen peroxide and hydroxy radicals as by-products of the fuel cell reaction. As a countermeasure, we examined the setting of a radical scavenger layer between the cathode catalyst and the polymer membrane.
The effects of seven type of radical scavenger were examined by an OCV accelerated durability test. Cells to which cerium carbonate was added as a radical scavenger, were found to be about 10 times more durable than the standard cell without a radical scavenger.
The effectiveness of adding cerium carbonate in an actual-size cell was confined in a daily start and stop (DSS) accelerated durability test base on the most severe practical operating conditions expected.View full abstractDownload PDF (5156K) -
Hirofumi Sumi, Seigo Kurachi, Toru Hiroyama, Yoshito Umeda, Kazunori O ...Article type: Research Paper
Subject area: Energy
2009 Volume 35 Issue 3 Pages 312-317
Published: May 20, 2009
Released on J-STAGE: May 27, 2009
JOURNAL RESTRICTED ACCESSAn integrated adsorption heat pump with zeolite absorbent, which contained an adsorber and evaporator/condenser in the same vessel, was evaluated. At evaporation/condensation temperatures of 293 K, an adsorption temperature of 303 K, a desorption temperature of 363 K and a cycle time of 150 s, an output thermal power of 3.27 kW and a COP of 1.37 were obtained against theoretical power of 4.35 kW and COP of 1.64. The COP decreased with shortening the adsorption/ desorption cycle time, because the rates of generation of adsorpton and latent heat were slow, and the sensible heat of adsorbent and heat exchanger was dominant immediately after switching the cycle. The output thermal power and COP decreased at low ambient temperature due to a reduction of evaporation performance, and at high supplied water temperature due to a decrease of an amount of adsorbed water.View full abstractDownload PDF (2345K)
Environment
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Hiroyuki Okamoto, Yasumitsu Uchihashi, Luong Ngoc Khanh, Teruo Miyahar ...Article type: Research Paper
Subject area: Environment
2009 Volume 35 Issue 3 Pages 318-327
Published: May 20, 2009
Released on J-STAGE: May 27, 2009
JOURNAL RESTRICTED ACCESSThe study was carried out for the pretreatment of brewery wastewater to remove nitrogen efficiently using anammox reaction in the plant of Asahi Breweries, Ltd. Organic compounds were removed in the first aeration tank (effective volume 360 L) fitted with a thread type acrylic fiber biomass carrier, and the subsequent partial nitritation was successfully achieved in the same type of second aeration tank. A two-stage pretreatment system for anammox process was operated continuously for half a year and the results showed that 1.5–2.4 kg-TOC/m3/d TOC removal rate was obtained in the first aeration tank and 1.5–2.5 kg-NH4/m3/d ammonia conversion rate was obtained from second partial nitritation reactor. Except sudden inflow of high concentrated wastewater or suspended solids and miss operation, pretreatment for anammox was achieved for a month in which 80% of organic carbon was removed and nitritation rate was approximately 50%.View full abstractDownload PDF (1011K) -
Hiroyuki Okamoto, Yasumitsu Uchihashi, Luong Ngoc Khanh, Teruo Miyahar ...Article type: Research Paper
Subject area: Environment
2009 Volume 35 Issue 3 Pages 328-335
Published: May 20, 2009
Released on J-STAGE: May 27, 2009
JOURNAL RESTRICTED ACCESSAnammox process was applied to remove nitrogen from pretreated brewery wastewater. Organic carbon removal and partial nitritation treatment were carried out by two stage pretreatment processes using a thread type acrylic fiber biomass carrier as the pretreatment of the sludge reject water of Asahi Breweries, Ltd. Plug-flow type anammox reactor, which is considered to be the smallest reactor volume and least driving power based on the theory of reaction engineering, was applied for the treatment of partially nitrified reject water. Malt Ceramics (MC), produced from carbonized spent grains were filled as a biomass carrier for anammox sludge. Results of this study indicate that the anammox process can operate under extremely HRT with low NH4-N concentrated wastewater. Maximum volumetric loading rate of 4.17 kg-N/m3/d was obtained under HRT of only 42 min. It is demonstrated that our invented anammox reactor can be operated even in high C/N ratio such as 0.196. The study has developed such a technology that would make anammox process very fast in a very small reactor.View full abstractDownload PDF (4240K)
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