The <i>Terra Incognita</i> of Sampling: Grouping and Segregation


Dihalu, D.S.

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Delft University Press


It is essential in manufacturing companies, including environmentally oriented organizations, that each individual product or test portion is well-defined for the sake of product wellness, general health and safety, and quality assurance. Therefore it is justified that a significant share of the total company budget is spent on quality management. Ideally, each product that is produced in a company is tested for correctness. But for mass-producing companies in the food and feed industry, as well as pharmaceutical companies, this is not a realistic goal, In order to still get an impression of product quality, a representative sample of the product is tested in a laboratory. The inevitable deviation between the sample and the true product properties is known as the sampling error.Sampling is a multi-disciplinary topic that has been the inspiration for many scientists who tried to construct formulas that predict the fundamental sampling error.

The main topic of this thesis concerns the grouping and segregation of particulate materials in a mixture. The consequence of the physicochemical ordering of particles in terms of the fundamental sampling error has been largely overlooked in the sampling sciences. In this publication, the utmost attention is paid to the influence of grouped or segregated particles on the fundamental sampling error, and it is discussed how grouping and segregation of particles can be measured physically. The techniques and insights proposed here might contribute to the sampling sciences by completing a – yet utopic – universal Theory Of Sampling.