Journal of the Society of Powder Technology, Japan

[title in Japanese]

Michitaka Suzuki

2004 Volume 41 Issue 3 Pages 155
Published: March 10, 2004
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.4164/sptj.41.155

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Particle Shape Measurement Using X-ray Micro Computed Tomography

Michitaka Suzuki, Kohei Kawabata, Kenji Iimura, Mitsuaki Hirota

2004 Volume 41 Issue 3 Pages 156-161
Published: March 10, 2004
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.4164/sptj.41.156

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Particle shape is one of the important particle properties, but most particle shape indices are obtained from 2-dimensional projected particle images. Recently, X-ray micro computed tomography was developed and applied to the observation of powder packing structure. We utilized X-ray micro CT Scan for 3-dimensional particle shape measurements including holes, concave surfaces and internal voids. The volume and surface area of a particle can be calculated by integrating the cross sectional area and the perimeter of particle images using X-ray micro CT. Based on our experimental results, the surface area and volume of a particle larger than 60-100μm can be measured with a high degree of accuracy. Wadell's sphericity and circularity are calculated from the surface area and the volume of test particles and compared to each other. As a result, the values of Wadell's sphericity of tablet, hollow particle, cubic and hollow cylinder are not equal to the circularities but they agree for spherical particle. This suggests that 3-dimensional measurements are necessary in the shape analysis for non-spherical particles.

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Adhesion Force between Particle and Substrate in Humid Atmosphere Studied by Atomic Force Microscope

Akio Fukunishi, Yasushige Mori

2004 Volume 41 Issue 3 Pages 162-168
Published: March 10, 2004
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.4164/sptj.41.162

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Using an atomic force microscope (AFM), adhesion forces between glass particles or AFM tips and hydrophilic or hydrophobic substrates were measured as a function of relative humidity (RH). The observed adhesion force between the glass particle and the hydrophilic substrate increased with RH, due to strong capillary condensation. In contrast, the adhesion force between the glass particle and the hydrophobic substrate was found to be almost constant for all RH, due to weak capillary condensation. The adhesion force between an AFM tip and a mica plate had a maximum value at a certain RH. This can be evaluated by calculating with consideration for the tip shape. On the other hand, the adhesion force for a silica plate increased drastically over a certain RH, and could be explained due to the surface roughness of the silica plate. The presence of nanometer scale roughness can play a critical role in the absolute value of the adhesion force between an AFM tip and the substrate in humid atmosphere.

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Evaluation of Pharmaceutical Glidant with Atomic Force Microscope and Mechanism of Flowability Enhancement

Kotoe Machida Ohta, Kenzo Toyoshima, Masayoshi Fuji, Takashi Takei, Ma ...

2004 Volume 41 Issue 3 Pages 169-176
Published: March 10, 2004
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.4164/sptj.41.169

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The effect of geometric surface structure of glidant on flowability of pharmaceutical fillers and the factors that determine the optimum amount of glidant added were investigated with AFM and IR spectroscopy. Several types of silica particles were used as a glidant in preparing the mixture of lactose and microcrystalline cellulose. The flowability of mixed powder was evaluated with Can's index. As a result, it was found that the flowability and the optimum mixing ratio depend on the geometric surface structure of glidant. AFM study showed that the porosity of silica particles plays an important role in determining flowability through the reduction in adhesion force. Furthermore, IR study suggested that the optimum mixing ratio is closely related to the surface coverage of filler with glidant. The optimum mixing ratio of porous silica is smaller than that of nonporous silica since the surface coating with porous silica is completed at a lower mixing ratio.

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Evaluation of Uniformity of Powder Mixture with a Local Analysis Method

Minimum Number of Measurements Required for Sampling

Yuki Nakahara, Akira Tsuge, Tetsuo Uchida, Yoshinori Uwamino, Hisashi ...

2004 Volume 41 Issue 3 Pages 177-182
Published: March 10, 2004
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.4164/sptj.41.177

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A method for evaluating uniformity of a mixed powder is proposed based on a local analysis method. The number of measurements for a given volume or mass at different locations in mixed powder to ensure the uniformity of sampling from the standard deviation, was calculated with a simple statistical model. The calculation result for the measurements with micro FT-IR as a local analysis method suggested that more than 20 measurements are required in order to ensure the uniformity of sampling of mixed powder, which was also confirmed through the experiments.

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Symphony of Materials and Processing in the Printing Industry

Koji Kuroda

2004 Volume 41 Issue 3 Pages 183-189
Published: March 10, 2004
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.4164/sptj.41.183

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Measurement of Size Distribution and Zeta Potential of Particles in Highly Concentrated Slurries

Shin-ichi Takeda

2004 Volume 41 Issue 3 Pages 190-196
Published: March 10, 2004
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.4164/sptj.41.190

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Measuring Techniques and Application Methods of Mechanical Properties of Fine Powders

Mitsuaki Hirota

2004 Volume 41 Issue 3 Pages 197-205
Published: March 10, 2004
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.4164/sptj.41.197

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[title in Japanese]

[in Japanese], [in Japanese]

2004 Volume 41 Issue 3 Pages 206-213
Published: March 10, 2004
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.4164/sptj.41.206

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[title in Japanese]

2004 Volume 41 Issue 3 Pages 214
Published: March 10, 2004
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.4164/sptj.41.214

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[title in Japanese]

2004 Volume 41 Issue 3 Pages 215-217
Published: March 10, 2004
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.4164/sptj.41.215

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[title in Japanese]

Katsuyoshi Tanida

2004 Volume 41 Issue 3 Pages 224-225
Published: March 10, 2004
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.4164/sptj.41.224

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[title in Japanese]

[in Japanese]

2004 Volume 41 Issue 3 Pages 227
Published: March 10, 2004
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.4164/sptj.41.227

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