Particle & Particle Systems Characterization

Cover image for Particle & Particle Systems Characterization

April, 2006

Volume 22, Issue 5

Pages 289–357

    1. Electrostatic Charge Measurement and Charge Neutralization of Fine Aerosol Particles during the Generation Process (pages 293–298)

      Chuen-Jinn Tsai, Jyh-Shyan Lin, C. G. Deshpande and Li-Chun Liu

      Version of Record online: 25 APR 2006 | DOI: 10.1002/ppsc.200500961

      An aerosol charge analyzer has been constructed and was applied to measure the charge distribution of NaCl particles in a size range from 10 nm to 800 nm. It is shown that particle charges are significantly higher than equilibrium charge. Furthermore, it is demonstrated that using a radioactive charge neutralizer the aerosol charge approaches Boltzmann equilibrium.

    2. On Different Approaches to Estimate the Mass Fractal Dimension of Coal Aggregates (pages 299–309)

      Jimmy Y. H. Liao, Cordelia Selomulya, Graeme Bushell, Götz Bickert and Rose Amal

      Version of Record online: 25 APR 2006 | DOI: 10.1002/ppsc.200500978

      Loose and compact coal aggregates were generated through flocculation of ultrafine coal particles. Aggregate structure in terms of mass fractal dimension Df was determined using various methods; namely image analysis, interpretation of intensity patterns from small angle light scattering, changes in aggregation state through light obscuration, and settling behavior. The appropriate utilization of a particular method is discussed in detail an how the choice is determined by system properties and required data quality.

    3. Determination of Particle Size Distribution by Laser Diffraction of Doped-CeO2 Powder Suspensions: Effect of Suspension Stability and Sonication (pages 310–319)

      Marie J. Desroches, Ian A. Castillo and Richard J. Munz

      Version of Record online: 25 APR 2006 | DOI: 10.1002/ppsc.200500996

      In this study the characterization of fine ceramic powders which are subject to strong agglomeration leading to biased results for the size distribution is investigated. The effect of dispersant, pH control and sonication on the resulting size distribution and the zeta potential are discussed in detail and an optimum procedure to obtain primary particle sizes is given. The results can be used in the analysis of ceramic powders in which strong particle agglomeration is present.

    4. Scattering and Transmission by a Monolayer of Spheres: A Study on the Monolayer Structure (pages 320–328)

      Jianqi Shen, Ulrich Riebel and Xiaoai Guo

      Version of Record online: 25 APR 2006 | DOI: 10.1002/ppsc.200500979

      The angular distribution of scattered light and the transmission of radiation through a monolayer of monodisperse spherical particles at variable particle concentration are studied. The scattering of light by a single particle is calculated with the classical Lorentz Mie theory. It is found that the scattering pattern, especially in the forward and backward directions, and the transmission are strongly dependent on the monolayer density.

    5. Organization of Functionalized Gold Nanoparticles by Controlled Protein Interactions (pages 329–335)

      Ananiys Kohut, Andriy Voronov and Wolfgang Peukert

      Version of Record online: 25 APR 2006 | DOI: 10.1002/ppsc.200500986

      This study demonstrates the self-assembly of gold colloidal nanoparticles. This is achieved using specific interactions of avidin with biotin which leads to the controlled cross-linking of particles. The progress of the process was characterized by optical absorption spectroscopy, dynamic light scattering and HRSEM. The degree of flocculation was measured and quantified by a semi-empirical parameter and its dependence on the experimental parameters is given.

    6. Hybrid Comminution with High-Pressure Roller and Stirred Bead Milling (pages 336–344)

      Yanmin Wang, Eric Forssberg and Peng Lin

      Version of Record online: 25 APR 2006 | DOI: 10.1002/ppsc.200500975

      This paper presents the experimental results on wet grinding of a moist calcium carbonate material in a hybrid comminution system, which consists of a high pressure roller mill (HPRM) and a subsequent stirred bead mill. The results show that the pre-treatment can result in considerable energy savings and efficient size reduction. The role of HPRM as pre-treatment is elucidated by a thorough discussion of the formation of micro-cracks in the particles under the compressive loads.

    7. Technical Note: Powder Production by Gas Atomization of Bioglass Melt (pages 345–351)

      Zanjun Huang, Cevin Czisch, Peter Schreckenberg, Frank Büllesfeld and Udo Fritsching

      Version of Record online: 25 APR 2006 | DOI: 10.1002/ppsc.200500966

      Bioglass melts are granulated by hot gas atomization technique where spherical powder and fibre type products respectively are available according to different process parameters. Particle size analysis, Scanning Electron Microscopy and optical observation of the atomized materials are performed. The melt disintegration mechanism and the particle shape and size dependency on process parameters are discussed.