Dispersion Martin diameter

The terms dispersion characteristic and respective or constituent amount need further explanation. The dispersion characteristic, also called particle size, grain size, fineness index, or dispersion parameter, is a physical property which can be measured and defines, in a suitable way, the dispersity or, in a narrower sense, the dimensions of the particles. In the case of spheres, diameter would be the most descriptive dispersion characteristic. If the particles are irregularly shaped, other linear dimensions must be chosen, e.g. the statistical chord lengths according to Martin or Feret (Figure 21), the mesh size of a screen through which the particle just passes, or so-called equivalent diameters. Equivalent diameters are calculated from other dispersion characteristics, which must not necessarily be linear dimensions, using mathematical relationships and/or physical laws. 

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