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Volume 34, Issue 9
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1997 Volume 34 Issue 9 Pages 218
Published: 1997
Released on J-STAGE: April 30, 2010
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Shunsaku KATOH1997 Volume 34 Issue 9 Pages 645
Published: September 10, 1997
Released on J-STAGE: April 30, 2010
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Masayoshi FUJI, Shoichi UENO, Takashi TAKEI, Tohru WATANABE, Masatoshi ...1997 Volume 34 Issue 9 Pages 646-652
Published: September 10, 1997
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSThe molecular dynamics (MD) method and IR spectroscopy have been applied to investigate the conformations of several normal alkoxyl groups grafted on a silica surface. The structures of octhyl (C8), dodecyl (C12) and octadecyl (C18) alkoxyl groups at about a maximum loading value were focused on. The conclusions of the study were as follows: (1) The difference in the maximum loading values between C8 and C18 alkoxyl groups was estimated to be 20% at most, which was smaller than that expected from the balkiness of the groups; (2) The results of the MD simulation are nearly in accordance with those obtained by IR measurements. The fraction of that structure in the total segments of the groups introduced is constant or decrease slightly depending on their lengths; (3) The length effect of the groups on the conformation was assumed by MD simulation. These estimations are not obtained by the experimental method. It is suggested that MD simulation is very useful for surface designing and prediction of its surface properties; (4) The results of MD simulation and IR measurement demonstrate that at a higher degree of modification of a few segments near the modified sites are rigid, and the terminal part of the alkoxyl group is flexible.View full abstractDownload PDF (936K) -
Nobuyuki ANDO, Manabu TAKEUCHI1997 Volume 34 Issue 9 Pages 653-659
Published: September 10, 1997
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSCarbon black powders were grafted with a polymer by using a reactive polymer, and their characteristics were examined. First, a reactive polymer, which easily reacted with the carbon black particles, was prepared. Then, the graft reaction of the carbon black with the polymer was carried out. The polymer-grafted carbon black showed high dispersibility in both the dispersion solutions and the coated layers. The former and latter were suggested from small particle size of the carbon black and high gross value, respectively. The low viscosity of the polymer-grafted carbon black solution suggested its high stability. Spin-coated layers of the polymer-grafted carbon black had a good surface smoothness. The polymer-grafted carbon black dispersed binder layer showed smooth change in electrical resistivities with the carbon black concentration. It can be concluded that grafting carbon black particles with a reactive polymer improves their dispersibility and stability.View full abstractDownload PDF (801K) -
Kunio UCHIDA, Yasunori KURIKI, Yoshiharu TASAKA, Kunio KAMIYA, Akiko K ...1997 Volume 34 Issue 9 Pages 660-665
Published: September 10, 1997
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSUltrafine molybdenum sulfide (MoS2) particles were prepared with a media agitating mill. In the milling, n-decane was used as a grinding solvent in which oleic acid was added. Natural and synthesized Aldrich MoS2 particles were used. The median diameters of both particles became about 40nm after milling for 50 hours. After the milling, both particles held crystalline structures, though the peak profiles measured by XRD broadened.
The catalytic activity of the prepared MoS2 particles was investigated with the hydrogenation reaction of 1-methyl-naphthalene (1-MN). The mechanically milled MoS2 particles had a much higher conversion of 1-MN per weight of catalyst than that of either starting natural or synthesized MoS2 particles. On the other hand, the conversion of 1-MN per surface area of catalyst depended on the kind of MoS2 particles used in the reaction. The conversion of 1-MN per specific surface area by milled synthesized Aldrich MoS2 was higher than that of starting particles, while the conversion by milled natural MoS2 was lower. The reason for the difference might be attributed to the different edge structure of the MoS2.View full abstractDownload PDF (2267K) -
Masako SHIMIZU, Tatsushi MATSUYAMA, Hideo YAMAMOTO, Tomohide TANIMOTO1997 Volume 34 Issue 9 Pages 666-671
Published: September 10, 1997
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSThe Theta-composer is a new type of equipment developed for preparing composites of various particulate materials. In this study, yeast cells were disintegrated by a theta-composer using glass beads 1.0mm in diameter as the disruption medium. The efficiency of disruption was determined by the degree of released soluble protein. In this study, invertase (β-D-fructofuranoside fructohydrolase), ADH (alcohol dehydrogenase) and G-6-PDH (D-glucose-6-phosphate dehydrogenase) were assessed as representatives of the cell wall-bounded enzyme, the enzymes around the cell wall and cytoplasmic enzyme, respectively.
The rotor speed of the theta-composer was the specific factor influencing the degree of disruption. ADH and invertase were released faster than G-6-PDH. These results suggest that the theta-composer is effective in the selective release of the components from yeast cell by controlling the degree of disruption.View full abstractDownload PDF (2248K) -
Yoko TANAKA, Tatsushi MATSUYAMA, Hideo YAMAMOTO1997 Volume 34 Issue 9 Pages 672-678
Published: September 10, 1997
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSIn order to use them as carriers of enzyme immobilization, copolymers of methacrylic acid (MAA) and N-isopropylacrylamide (NIPAM) were synthesized as a thermo-responsive polymer which changes its water solubility in response to the temperature of the solution.
The phase separation temperature of MAA-NIPAM copolymer increased with increase in the MAA contents. The phase separation temperature of the copolymer was also sensitive to pH, while that of NIPAM homopolymer was not.
Invertase immobilized covalently on the thermo-responsive polymer (weight ratio 1:4), was soluble below 40°C, and insoluble above 61°C in 0.1M acetate buffer (pH 5.0). The phase separation temperature also depended on the pH of the solution. The invertase immobilized on the thermo-responsive polymer maintained its activity at pH 3-7, and its stability on pH was improved comparing with free enzymes. The ratio of the activity of the immobilized enzyme to that of the free one was continuous around the phase separation temperature. This result should be regarded as important because it means that it is not necessary to strictly control the temperatures of the reaction and phase separation.View full abstractDownload PDF (767K) -
Hideo WATANABE, Tatsushi MATSUYAMA, Hideo YAMAMOTO1997 Volume 34 Issue 9 Pages 679-683
Published: September 10, 1997
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSIf the size of an immobilized enzyme particle can be reduced using enzyme immobilization by the entrapment method, the effectiveness factor is expected to increase In this work, the atomization of sodium alginate aqueous solution containing enzyme was performed by an electrostatic atomization method to produce a small immobilized enzyme particle of than 1mm in diameter. The effectiveness factor of the immobilized enzyme prepared by this method qualitatively agreed with the theoretical value. However, if the diameter is less than 1mm, the effectiveness factor was smaller than theoretical value. It was experimentally confirmed that there was no denaturation of the enzyme caused by the electrical field. Therefore, it is thought that leakage of the enzyme occurs during the immobilization process for the smaller particle diameter, making enzyme concentration in the particle low.View full abstractDownload PDF (567K) -
Hideto YOSHIDA, Kunihiro FUKUI, Kouji KANAGAWA, Mitsuru OKAMOTO, Chi-M ...1997 Volume 34 Issue 9 Pages 684-689
Published: September 10, 1997
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSExperimental and theoretical studies have been conducted on the separation of fine powders by the use of a revised louver type separator. The louver separator has movable plates, and the cut size can be controlled ranging from 10 to 20μm by changing the angle of the louver plates and the inlet velocity.
The 50% cut size decreases with the number of louver plates because the probability of collision with the louver plate decreases as the number of louver plates decreases. A new type of louver plates based on Joukowski's theory indicates superior classification sharpness compared with the flat-type plate.
The finite-element method employing a variational technique was used to solve the Navier-Stokes equations in a two-dimensional channel. The calculated partial separation efficiency agreed with the experimental results. The effect of increasing the scale of the louver separator was also calculated by use of numerical simulation, and it was found that the 50% cut size increases with the scale-up factor.View full abstractDownload PDF (730K) -
Yuji ISSHIKI, Kunihiro FUKUI, Hideto YOSHIDA, Akira KOBAYASHI1997 Volume 34 Issue 9 Pages 690-696
Published: September 10, 1997
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSThe customary standard hydrocyclone is defective in that the fine particles mixes with the blow down slurry as much as the blow down rate. The methods of overcoming this defect were investigated. By use of an apex cone at the inlet of the dust box and the blow up method, the amount of fine particles in the blow down slurry was decreased, and the separation efficiency was improved. Furthermore the flow field and particle trajectory in the hydrocyclone were numerically simulated by using the LES model. From the simulated results, it was confirmed that an increase in the cut size and a decrease in the fine particles's collection efficiency by the blow up method were achieved by increasing the upward flow velocity along the center axis and decreasing the slurry volume which enters the dust box.View full abstractDownload PDF (1817K) -
Kenichi SODEYAMA, Yoshio SAKKA, Yoshitaka KAMINO, Hiromitsu SEKI, Kenr ...1997 Volume 34 Issue 9 Pages 697-703
Published: September 10, 1997
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSA new method of production of fine Shirasuballoons from glassy volcanic fragments, named Shirasu, was developed. Finer Shirasuballoons were required to replace conventional Shirasuballoons. However, the pulverized Shirasu is easily agglomerated and clogged; therefore, they cannot be supplied continuously to the furnace. It was shown that the flowability and the floodability of the pulverized Shirasu were improved by a dry surface treatment. The fine Shirasuballoons of mean particle sizes under 20μm were successfully prepared in a fluidized bed furnace by rapid heating of the pulverized Shirasu after the surface treatment. The foaming characteristics of the fine Shirasuballoons depended on the preheat treatment of the pulverized Shirasu in the temperature range of 150-300°C; an increase in pre-heat temperature resulted in decrease in the expansion ratio of the fine Shirasuballoons.View full abstractDownload PDF (2449K) -
Akira NAKAMURA, Yoshikazu YAMAGUCHI, Eiichi ONUMA, Yutaka SASAKI, Tamo ...1997 Volume 34 Issue 9 Pages 704-708
Published: September 10, 1997
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSIn the permeability measurement of surface-treated cements in the cement powder grouting method, the humidity of air injected with cement into the sand specimen was found to have a considerable effect on the test results. The allowable range of the relative humidity of air was proposed as 10-20%. Correspondingly, the requirements for the water content condition in the test site using the cement powder grouting method were discussed, and the degree of saturation of the site was concluded to be one of the most appropriate criteria in the applicability of the method.View full abstractDownload PDF (528K) -
Masunori SUGIMOTO, Satoshi TSUZUKU, Kenichi YAMAMOTO, Daisuke TOJIMA1997 Volume 34 Issue 9 Pages 709-717
Published: September 10, 1997
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSIn order to produce small composite granules having binary components of CaCO3 and SiC powders, experiments were carried out by the simultaneous operation of granulation, grinding and separation in a single continuous rotating conical vessel with a grinding media. To characterize these composite granules, SiC agglomerates included in a granule were separated by chemical methods, and the size distributions of granules and these SiC agglomerates were measured by an image analyzer through a microscope.
The structure in a composite granule was characterized by comparing the size of a composite granule with that of SiC agglomerates in the granule.
As a result, it was found that composite structures in each granule could be classified broadly into six kinds of structure models, and that the composite structure depended on the size of the granules and the volume fraction of the SiC component in the granule.View full abstractDownload PDF (2543K) -
Concerning in Environmental Problem and Energy-resoure SubjectKazunari OHGAKI1997 Volume 34 Issue 9 Pages 718-723
Published: September 10, 1997
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSDownload PDF (7098K)
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