KAGAKU KOGAKU RONBUNSHU
Online ISSN : 1349-9203
Print ISSN : 0386-216X
ISSN-L : 0386-216X
Volume 38 , Issue 2
Showing 1-12 articles out of 12 articles from the selected issue
Editorial Note
Physical Properties and Physical Chemistry
Transport Phenomena and Fluid Engineering
  • Kohei Ogawa, Chiaki Kuroda, Shiro Yoshikawa
    Type: Research Papers
    Subject area: Transport Phenomena and Fluid Engineering
    2012 Volume 38 Issue 2 Pages 80-86
    Published: March 20, 2012
    Released: March 20, 2012
    JOURNALS RESTRICTED ACCESS
    In general, an increase impeller speed in a stirred vessel operated in turbulent flow is expected to accelerate mixing, heat or mass transportation and reaction as plus factors. However, it also increases anxiety about the minus factors of higher power consumption of the impeller, damage of the impeller by fluid resistance or cavities behind the impeller blade and breakup of crystals. By considering both plus and minus factors together, namely, by adding a “human touch” that balances the degrees of expectation and anxiety, a method of determining the optimum impeller speed based on information entropy is discussed in the light of previous experimental results for versatile impellers, and a new method of determining optimum impeller speed is presented.
    Download PDF (1225K)
  • Yoshihito Kato, Azusa Nakaoka, Haruki Furukawa, Yutaka Tada, Song-Tae ...
    Type: Notes
    Subject area: Transport Phenomena and Fluid Engineering
    2012 Volume 38 Issue 2 Pages 87-89
    Published: March 20, 2012
    Released: March 20, 2012
    JOURNALS RESTRICTED ACCESS
    The effect of the baffle length on the power consumption of a mixing vessel with propeller impeller was studied experimentally. The power number of the propeller impeller can be correlated by the expression reported (Kato et al., 2009) with modified baffle length, regardless of the discharge flow direction of the propeller impeller.
    Download PDF (428K)
Separation Engineering
  • Nobuo Seki, Kie Kinoshita, Hitoshi Saitoh, Hiroshi Ochi, Keiji Iwatsuk ...
    Type: Research Papers
    Subject area: Separation Engineering
    2012 Volume 38 Issue 2 Pages 90-101
    Published: March 20, 2012
    Released: March 20, 2012
    JOURNALS RESTRICTED ACCESS
    Theoretical approach is tried to predict flux changes in nanofiltration of dairy whey. Solute quantities (A) in whey are considered to classify into two parts namely one part is membrane permeable solute (Ap) and another part is membrane non-permeable solute (Ar).
    Whey solution (0.1 ton of weight and solids concentration 5.34%) to solve the commercial whey powder, was concentrated by means of nanofiltration unit (Element's effective membrane area is 7.4 m2) up to 2.2 folds by weight in batch concentration system. The flux changes were measured during nanofiltration concentration under the operating conditions of 10°C, 1.2 MPa and feed rate of whey solution to nanofiltration element 1 m3/h.
    The analytical results show that total solute in the initial whey solution are 20.92 mol, and 0.391 of molar ratio of total solute is the permeable solute and residual 0.609 of molar ratio is the non-permeable solute. The permeability coefficient of permeable solute was determined 0.737 from it's concentration per water. A permeable solute will show some osmotic pressure difference through membrane, but it is considered that a permeable solute does not show concentration-polarization phenomena, and a non-permeable solute is considered to form concentration-polarization phenomena.
    In this concept, nanofiltration of whey can be analyzed as reverse osmosis concentration of non-permeable solute in whey regarding flux changes.
    To calculate osmotic pressure using freezing-point depression analysis, Morse and Frazer's equation showed better coincidence with data than van't Hoff's equation.
    Download PDF (1241K)
  • Hiroaki Yoshida, Yoshimasa Amano, Motoi Machida
    Type: Research Papers
    Subject area: Separation Engineering
    2012 Volume 38 Issue 2 Pages 102-109
    Published: March 20, 2012
    Released: March 20, 2012
    JOURNALS RESTRICTED ACCESS
    Two types of de-ashed (DA) activated carbon were prepared by oxidation (DAOx) and outgassing (DAOxOG) treatment to introduce and reduce surface acidic functional groups. Adsorption of 11 kinds of aromatic compounds on DAOx and DAOxOG was examined experimentally, and adsorption isotherms were obtained for each adsorbate. The adsorption/desorption kinetics of two adsorbates, nitrobenzene and phenol, were further examined to clarify the adsorption mechanisms. The results showed that DAOxOG adsorbed higher amounts of all 11 aromatic compounds than DAOx over the range of concentration tested. Also, the adsorptive behavior on DAOx and DAOxOG differed for each adsorbate. For nitrobenzene, the amount adsorbed on DAOx increased with the increase in the concentration, and the maximum amount was close to that adsorbed on DAOxOG. These trends were not found in the case of phenol. Nitrobenzene and phenol also showed different adsorption and desorption rates on DAOx. These results suggest that the difference in adsorptive behavior of adsorbates on the two types of activated carbons is due to the different adsorptive form of adsorbates caused by the different polar characteristics of their substituent groups.
    Download PDF (1108K)
Process Systems Engineering and Safety
  • Tsutomu Takai, Masaru Noda, Fumitaka Higuchi
    Type: Research Papers
    Subject area: Process Systems Engineering and Safety
    2012 Volume 38 Issue 2 Pages 110-116
    Published: March 20, 2012
    Released: March 20, 2012
    JOURNALS RESTRICTED ACCESS
    The event correlation analysis is a knowledge extraction method that detects statistical similarities among the discrete events of alarms and operations. The method uses operation data from a plant to quantify the degree of similarity between events separated by a time-lag by evaluating the cross correlation function. If high similarity between two events is not detected, the time window size is doubled, and the log data of two events are reconverted into sequential binary data using the new time window size. The expansion of the time window size and recalculation of the similarity continues until either high similarity is detected or the time window size becomes larger than the maximum pre-determined size. We applied the method to the plant operation data of an ethylene plant. The results showed that it was able to correctly identify similarities between two physically related events, even when the conventional method using a constant time window size failed due to the large variance in time lag. Using the method, we can effectively identify nuisance alarms and routine operations within a large amount of event data.
    Download PDF (1548K)
Materials Engineering and Interfacial Phenomena
  • Hiroshi Sato, Tomo Taira, Katsuyasu Sugawara
    Type: Research Papers
    Subject area: Materials Engineering and Interfacial Phenomena
    2012 Volume 38 Issue 2 Pages 117-122
    Published: March 20, 2012
    Released: March 20, 2012
    JOURNALS FREE ACCESS
    In order to synthesize thin and dense films of metallic copper and nickel for base metal electrode type multilayered ceramic capacitor BME-MLCC at low temperature, changes of chemical forms and morphology were investigated for wet chemically derived precursors from copper acetate monohydrate and nickel acetate tetra-hydrates during heat treatments. Mono and bimetallic films of copper and nickel could be prepared from the precursors by heat treatments at the temperatures from 200 to 300°C in a nitrogen stream. The optimum amount of tetra-ethylene glycol as a solvent in the wet chemical preparation was 3–4 mol per one mol of copper acetate monohydrate or nickel acetate tetra-hydrates. The content of each metal in the copper–nickel alloy film could be easily controlled by changing the mixing ratio of the precursors of copper and nickel. The precursors of mono and bimetallic films were coated to the terminal of multi-layered ceramic capacitor and heated at 500°C in a nitrogen stream. Uniform and thin terminal electrode was obtained successfully with no appreciable diffusion of copper into the inner electrode and cracks in the BaTiO3 layers. The wet chemically derived precursors promise to be desirable terminal electrode of base metal electrode type multilayer ceramic capacitor BME-MLCC at low temperature heat treatment.
    Download PDF (2583K)
Energy
  • Yohsuke Matsushita, Noriko Mitsuhara, Seiichiro Matsuda, Tatsuro Harad ...
    Type: Research Papers
    Subject area: Energy
    2012 Volume 38 Issue 2 Pages 123-128
    Published: March 20, 2012
    Released: March 20, 2012
    JOURNALS RESTRICTED ACCESS
    Fundamental drying behavior of as-mined Loy Yang coal with water content of 56 wt%, a Brown coal from Victoria State, Australia, was investigated. Weight loss due to drying was measured and drying rate was evaluated at a constant temperature of 50–90°C or a constant heating rate of 1–100°C/min. At a constant temperature, the drying rate of Brown coal showed its maximum value in the first period of drying after the heating-up period and decreased gradually. The drying behavior of Brown coal was different from that of wood, one of the best-known materials in drying, which showed two drying periods, the so-called constant-rate and decreasing-rate drying periods. From the measured data obtained at a constant temperature, the drying rate of Brown coal found to be expressed by the equation proportional to (1−X) with drying fraction X and a proportionality constant, in other words, the drying rate constant was proportional to drying temperature. The validity of the proposed drying rate equation was confirmed by comparing the predicted weight loss obtained by the equation with measured one both at a constant temperature condition and at a constant heating rate. The predicted weight loss due to drying was in good agreement with the measured one in the first and middle drying period after the heating-up period, though that in the final drying period was overestimated. Moreover, the times to achieve various drying fractions were estimated from the measured data and the drying rate equation at constant temperature condition. As a result, the time to achieve a given drying fraction increased with a decrease in drying temperature, and the time to achieve a higher drying fraction drastically increased with a decrease in drying temperature.
    Download PDF (961K)
Environment
  • Atsushi Iizuka, Masato Honma, Yasuyuki Hayakawa, Akihiro Yamasaki, Yuk ...
    Type: Research Papers
    Subject area: Environment
    2012 Volume 38 Issue 2 Pages 129-134
    Published: March 20, 2012
    Released: March 20, 2012
    JOURNALS RESTRICTED ACCESS
    A new carbon dioxide sequestration process was proposed. The process consists mainly of a calcium extraction step from concrete sludge by water dilution with stirring and a calcium carbonate precipitation step by the reaction of extraction solution and gaseous carbon dioxide. Experimental data for the proposed process was obtained using real concrete sludge generated from a concrete pole/pile plant. The influences of water dilution ratio (weight ratio: 3–50) and extraction treatment time (5–40 min) on the calcium extraction rate from concrete sludge were investigated. It was confirmed that the calcium concentration in water increased sufficiently for calcium carbonate to be precipitated by the reaction with gas containing carbon dioxide (10%). In the range of experimental conditions studied, the dilution ratio of 20 and the extraction time of 5 min were found to be the optimal treatment conditions for calcium extraction from concrete sludge. The calcium carbonate precipitation step from calcium solution is easily accelerated by the addition of seed crystals. These results indicate that concrete sludge can be used as a cheap calcium resource for carbon dioxide sequestration.
    Download PDF (631K)
  • Yuichi Ohira, Manabu Wakasa, Masamitsu Shimadzu, Eiji Obata
    Type: Notes
    Subject area: Environment
    2012 Volume 38 Issue 2 Pages 135-138
    Published: March 20, 2012
    Released: March 20, 2012
    JOURNALS RESTRICTED ACCESS
    Effect of addition of magnesium nitrate hexahydrate on the reactivity of soft-burned magnesia was experimentally investigated. We found that the reactivity of magnesite which passed 280 mesh was 0.070, and the reactivity of that was increased by calcining. When magnesium nitrate hexahydrate was added to magnesite, the soft-burned magnesia with a high reactivity was produced in heating for a short time.
    Download PDF (547K)
feedback
Top