Journal of the Society of Powder Technology, Japan
Online ISSN : 1883-7239
Print ISSN : 0386-6157
ISSN-L : 0386-6157
Volume 44, Issue 6
Displaying 1-9 of 9 articles from this issue
  • Takahiro Nishita, Yasuo Yamazaki
    2007 Volume 44 Issue 6 Pages 420-426
    Published: June 10, 2007
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
    Crystallization process is often applied to fine particle production and functional materials. Crystal structure and crystal size determine the particle function. Design of crystallization process is usually very difficult because of the complicated crystallization phenomena, such as nucleation and growth. Design method of a crystallizer provides both operation condition and size of crystallizer. Population balance model and material balance are described by two equations and five characteristic factors of crystallization. The authors developed an add- in software which solves equations on spread sheet software.
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  • Kazunori Kadota, Ikumi Matsumoto, Yoshiyuki Shirakawa, Atuko Shimosaka ...
    2007 Volume 44 Issue 6 Pages 427-433
    Published: June 10, 2007
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
    Liquid-Liquid interfacial crystallization has been carried out in NaCl aqueous solution/1-butanol and/2-butanone systems. The crystallization at the interface between NaCl aqueous solution and organic liquid was proceeded by the supersaturation caused from the mutual diffusion of the aqueous solution and the organic liquid. The NaCl crystalline particles precipitated at the interface showed a bimodal size distribution by using a supersaturated aqueous solution. However, the precipitation in an unsaturated aqueous solution can produce NaCl crystals with unimodal size distribution.
    The precipitated NaCl crystals were asymmetric in shape. The asymmetry was derived from the dynamics of the aqueous solution, the organic liquid and self-weight of the particles. Consequently, the transport of the solution into the organic liquid was confirmed by measuring the electric resistance in the organic liquid phase as a function of the contact time. Furthermore, the precipitation mass and rate of NaCl particles measured for two types of organic liquids showed that the precipitation properties depend on types of organic liquids.
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  • Tomohiro Iwasaki, Kenji Murai, Satoru Watano
    2007 Volume 44 Issue 6 Pages 434-440
    Published: June 10, 2007
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
    This paper deals with the mechanism of crystal growth of layered octosilicate, called ilerite, in the hydrothermal synthesis in the presence of seed crystals. The seed crystals grew efficiently at the initial period of the crystallization process; however, the crystal growth rate decreased with an increase in their size. In addition, the seeding promoted the production of crystal nuclei and their growth, resulting in an increase in the formation of finer particles. The pH value of the solution increased as the progress of the synthesis reaction, resulting in inhibition of the crystal growth. In order to enhance the crystal growth, the hydrothermal synthesis with controlling the pH value was carried out. By decreasing the pH value to the initial one, the yield of ilerite reached over 80%, however, the particle size of products increased slightly because of the production of crystal nuclei and their growth.
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  • Toshiyuki Nomura, Toshihiro Mori, Hiroaki Arima, Yasuhiro Konishi
    2007 Volume 44 Issue 6 Pages 441-446
    Published: June 10, 2007
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
    Shape and size control of barium chromate nanoparticles using water-in-oil microemulsion formed by anionic surfactant AOT was examined experimentally. As a result, nanowire, nanorod, and nanodot could be synthesized by changing the raw ion concentration and the addition of ethanol as a poor solvent, and the nanowire and nanorod were self-assembled. It has been shown that the aspect ratio of the generated particles decreased with increasing chromate ion concentration or adding more ethanol. In contrast, the aspect ratio was almost constant even if the barium ion concentration was changed. The surfactant AOT has selectively adsorbed on the crystal faces along the a axis and suppressed their crystal growth. Furthermore, the generated nanoparticles were self-assembled by hydrophobic interaction between the surface-anchored AOT molecules. In conclusion, it was clarified that the supersaturation ratio and the particle-surfactant interaction were important factors for controlling the shape and size of inorganic nanoparticles using microemulsion method.
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  • Akira Watanabe, Motoharu Fujii, Masayoshi Kawahara, Takehisa Fukui, Ki ...
    2007 Volume 44 Issue 6 Pages 447-452
    Published: June 10, 2007
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
    Although several gas phase synthesis methods for nanoparticles have been developed, only few are adapted for mass-production of varoius types of nanoparticles. In this study, we developed a new method to synthesize oxide nanoparticles by gas phase reaction assisted with DC plasma. We chose ZrO2 and CeO2 as a model powder. TEM observation and specific surface area measurement showed that as-synthesized nanoparticles were in the size range of 5-100nm and they were not hollow but solid particles. From XRD results, as-synthesized nanoparticles had a high crystallinity without sintering. The present experiments suggested that the particle size is controlled by the oxygen gas feed rate of a carrier gas through a two fluid nozzle, i. e., an increase in oxygen feed rate leads to smaller nanopraticles at a constant precursor feed rate.
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  • Hiroyuki Tsujimoto, Yusuke Tsukada, Kaori Hara, Yoshiaki Kawashima
    2007 Volume 44 Issue 6 Pages 453-458
    Published: June 10, 2007
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
    New preparation techniques of PLGA nanospheres as delivery carrier for water-soluble and anionic NFkB Decoy Oligodeoxynucleotide (NDON) were studied. It was found that the cationic Chitosan (CS) coated PLGA nanospheres prepared by standard emulsion solvent diffusion method can support anionic NDON not only inside themselves but also on their outer layers by the electrostatic interaction between CS and NDON, by adding NDON to the CS coated PLGA nanosphere suspension.
    By optimizing concentration of CS and NDON in the method, three types of PLGA nanospheres which are 1) NDON encapsulated type, 2) Encapsulated/surface-supported type and 3) Surface-supported type can be prepared as NDON delivery particles.
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  • Hiroyuki Tsujimoto, Kaori Hara, Yusuke Tsukada, Yoshiaki Kawashima, Sh ...
    2007 Volume 44 Issue 6 Pages 459-464
    Published: June 10, 2007
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
    New granulation technique using a spouted bed type binderless granulator and a jet mill to make PLGA nano-composite granules applicable to DPI was studied. In the method, the PLGA nano-composite granules having a spherical shape with soft granule strength can be binderlessly granulated in the spouted bed using raw materials prepared by milling and blending freeze dried PLGA nanospheres and lactose powder as an excipient with a jet mill. The prepared nano-composite granules showed good handling properties with high respirable fraction (RF) values estimated by cascade impactor in vitro. The new method proposed in the present work proved to be a useful preparation technique of PLGA nano-composite granules for DPI application.
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  • Tsuyoshi Inoue
    2007 Volume 44 Issue 6 Pages 465
    Published: June 10, 2007
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
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  • Takashi Ogi
    2007 Volume 44 Issue 6 Pages 466-467
    Published: June 10, 2007
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
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