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Volume 44, Issue 4
Displaying 1-8 of 8 articles from this issue
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Hiroshi Yoshiba, Yoshiyuki Komoda, Hironobu Imakoma, Hiromoto Usui2007 Volume 44 Issue 4 Pages 234-241
Published: April 10, 2007
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSPET films were coated with slurries consisting of various sizes of particles using spin coating. The clusters of particles were formed in the coated layer. We studied the correlation between the number of primary particles in the clusters predicted by Usui's suspension model and the optical properties. All coated films showed a correlation between the number of primary particles and the opacity or transmittance. Especially for the primary particles with diameters of 13 and 6μm, we found a strong correlation with the coefficient of correlation higher than 0.9. On the other hand, the structure of film coated with 2μm particles changed during the drying process and the area occupied by the particles was decreased. Introducing a correction in the transmittance by the area decreased, we also obtained a strong correlation even for 2μm particle coated film.View full abstractDownload PDF (2732K) -
Masayasu Uemura, Kazuyoshi Sato, Hiroya Abe, Makio Naito, Kiyoshi Nogi ...2007 Volume 44 Issue 4 Pages 242-247
Published: April 10, 2007
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSEffect of Mn-Zn slurry preparation conditions on the properties of its sintered body was examined for a granule compaction process. Poly-vinyl alcohol (PVA) binder or poly-acrylic-acid (PAA) binder was used to prepare the aqueous slurry of Mn-Zn oxides powder. The granules prepared with the acrylic binder resulted in a higher density, fracture strength and saturation magnetic flux density of the sintered body. The granules with PVA had a higher compressive strength, and formed a sintered body with a larger pore and a lower density. A thick segregated binder layer was observed on the surface of granules when PVA was used, which contributed to the higher strength of the green body compared to the granules prepared with PAA binder.View full abstractDownload PDF (5868K) -
Kazuho Nakamura, Makoto Kawasaki, Naoko Sakuda, Kanji Matsumoto2007 Volume 44 Issue 4 Pages 248-258
Published: April 10, 2007
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSAlthough the up-flow filtration system with fibrous filtration media has some advantages in filtration rate and purity of filtrate, the particle trapping mechanism has not been fully understood. The filtration performances of PMMA particles, KANTO loam particles, and Kaolin floc with the up-flow filtration system were investigated using filtration beds with the height of 0.1-0.6m. For the filtration of PMMA particles the effects of flow rate, feed concentration, and particle size were studied with the 0.1m long filtration bed and we found that the filtration performances is well described by the deep filtration model, in which the particle are trapped on the surface of fibers in the initial stage of filtration followed the surface filtration with the layer of collected particles. The filtration performance of 0.4m long filtration bed was predicted from the filtration performance of 0.1m long filtration bed with the model. The filtration performances of KANTO loam particles in the 0.1m long filtration bed could be elucidated by the deep bed filtration model with a constant filtration coefficient but the model could not predict the filtration performance in the 0.6m long filtration bed. The filtration performance of Kaolin floc could be elucidated by the bed filtration model with a limitation of the amount of trapped particles. The particle trapping capacity and the particle trapping efficiency of those particles could be compared using the fitting parameter obtained from the model analysis.View full abstractDownload PDF (6190K) -
Kenji Kofu, Mitsuaki Ochi, Masahiro Takei2007 Volume 44 Issue 4 Pages 259-266
Published: April 10, 2007
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSErgun's equation is modified by introducing the ratio of straight length to particle perimeter and the wall effect of particle bed. It can predict the pressure drop of particle bed of any shapes of coarse particles for various air velocities and pipe diameters, with an error of less than 6%. The wall effect is significant when the ratio of pipe diameter to particle diameter is smaller than 10 and the air velocity is lower than 3m/s. Ergun's equation gives poor prediction for the bed of non-spherical particles because these particles are in contact with a large area which is related to the ratio of straight length on perimeter of particles. A large deviation is found for large ratio of straight length to particle perimeter.View full abstractDownload PDF (3804K) -
Masafumi Arakawa2007 Volume 44 Issue 4 Pages 267-275
Published: April 10, 2007
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSAggregate structure of fine particles and thread forming property of thick slurry was investigated. Slurries could be classified into three states of aggregate structure depending on the dispersant concentration. The rheological behavior of slurries was determined by the aggregate structure of fine particles. The relationship between the dispersion state of particles and the surface tension were measured by a drop weight method. As a result, the thread forming property of thick slurry is reflected on the surface tension and apparent viscosity, and therefore measurement of surface tension and apparent viscosity may give the information on particle dispersion state.View full abstractDownload PDF (3684K) -
Toshihiro Kawaguchi2007 Volume 44 Issue 4 Pages 276-282
Published: April 10, 2007
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSIt is difficult to measure a particle motion inside a dense granular flow or a fluid-particle flow because of the existence of other particles. MRI is one of the non-invasive measurement techniques for such flows. MRI can measure the velocity distribution (tagging method and phase method), which is an outstanding advantage of the MRI measurement. This paper briefly explains the principle of the MRI measurement. Then MRI is applied to some dense granular flows or fluid-particle flows, such as rotating drums, vibrated granular beds, hopper flows and spouted beds.View full abstractDownload PDF (10602K) -
Shuya Nakao2007 Volume 44 Issue 4 Pages 290
Published: April 10, 2007
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSDownload PDF (2279K) -
Makoto Kohga2007 Volume 44 Issue 4 Pages 291-292
Published: April 10, 2007
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSDownload PDF (2390K)
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