Effective Rheology of Bubbles Moving in a Capillary Tube

We calculate the average volumetric flux versus pressure drop of bubbles moving in a single capillary tube with varying diameter, finding a square-root relation from mapping the flow equations onto that of a driven overdamped pendulum. The calculation is based on a derivation of the equation of motion of a bubble train from considering the capillary forces and the entropy production associated with the viscous flow. We also calculate the configurational probability of the positions of the bubbles.Comment: 4 pages, 1 figur

Decision Aid Tools for the Preservation of Fruits by Modified Atmosphere Packaging

Modified atmosphere packaging (MAP) is commonly used for packing fruits and relies on the natural interplay between the produce physiology (consumption or production of gases and vapours) and the mass transfer properties of the packaging material (gases and vapours permeation values), with possible gas flushing, in order to reach optimal conditions of storage. Then success of MAP depends on the choice of the material, whose mass transfer properties must match produce requirements. Decision aid tool for MAP of fruits would aim at helping decision makers to find the best material for a given fruit, but are not yet well developed and commonly used. If virtual MAP models exist, their objective is to dimension gas permeabilities of the packaging material to the needs of the fruit. They do not take into account multi-criteria design such as cost and mechanical properties. Then, this chapter brings an overview on current researches and developments in the field of biological, material, and computing science that could lead to the development of such a tool in regard to constitution of databases, and reliability of optimization and interrogation procedures