Shape Effect in Size Characterization

The volume equivalent diameter (d) of a sphere calculated from a cylindrical particle is  

There are many different definitions in converting three-dimensional irregular-shaped particles into equivalent spheres. The following definitions are just a few often appearing in the literature  

The volume equivalent sphere is the one used in most sizing technologies involving volumetric measurement and the area equivalent circle is used often 

Although most modem particle characterization methods are developed, validated and presumably used for spherical particles or equivalent spherical particles, real particles are rarely such ideal. In many instances, particle shape affects powder packing, bulk density, and many other macroscopic properties. Shape characterization of particulate systems only scatters in the literature [60], since there are hardly any universal methodologies available. Several methods exist that use shape coefficients, shape factors, Fourier analysis, or fractal analysis to semi-quantitatively describe shape [Ij. 

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