The characterization of disperse (particulate) systems, referred to as particle measuring technology (PMT), is a specialized interdisciplinary field with a strong physical orientation affiliated to process engineering.
Disperse systems are described in the first instance by their particle size distribution (PSD); however, they can have very complex, multidimensionally distributed properties. In a particle collective, each individual particle can already be classified as a disperse system in its own right (e.g., agglomerate). Properties such as material composition, internal structure, shape, surface, size, volume, color, refractive index, magnetizability, density, porosity, dielectricity and strength but also properties of state such as position (in the sense of local concentration), speed, momentum and temperature are as a rule neither completely independent nor strongly correlated.
The physical effects in regards to measurement and sampling may depend on several, if not all, properties to a greater or lesser degree with the result that in practice for determining the target parameter the primary signal is evaluated only with the aid of assumptions, simplifications and models. If the measurement is based on a collective signal, as a rule a rather complicated inversion problem exists to obtain said distributed parameter.
All the partial aspects of a measurement, for example sampling, sample preparation, measuring effect, sensor, measurement system, evaluation, presentation/visualization, interpretation, use and process connection are collectively known as application.
The need for particle measurement technology results from various situations with very different requirements in some cases, as for example
Dr. M. Schäfer