Many of the "fluids" processed in the food industry have strange flow properties that cannot easily be predicted. This is an important question in industry, since engineers need to know how such systems flow through pipes in production plants or how different components mix together. To counter this lack of knowledge, the fluids are generally processed for longer than necessary, which often proves expensive and may affect the quality of the final product.
The University of Birmingham Positron Imaging Centre has developed a powerful technique to study the behaviour of crisps, yoghurt and ice cream - together with many other granular materials and viscous fluids - in a variety of industrial processes. In one case, the group labelled a single crisp using a positron-emitting radioisotope and added it to a rotating drum full of crisps. By tracking the movement of the labelled crisp, they could determine how uniformly the crisps were exposed to the flavouring that was added in the mixing process.
In the January issue of Physics World magazine, David Parker from the School of Physics and Astronomy at the University of Birmingham, UK writes about research at the university's Positron Imaging Centre .