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International audience; A bidisperse medium of large sand particles and small glass beads is mixed in a cylindrical vessel that is put in rotational motion around an eccentric static rod. The subsequent segregation occurring in the system is investigated primarily at the free-surface where the large particles concentration globally increases towards a limit value while oscillating. In order to gain deeper understanding of the intrinsic mechanisms causing the segregation, we also explore the dynamics in the bulk. Average residual bulk displacements fields both vertically and orthoradially could then be measured and show a secondary flow that counteracts the segregation process.

International audience; Wet granulation processes can be driven from low to high water content. In this study, we consider the model situation of the growth of a single wet aggregate rolling in a dry granular flow inside a rotating drum. We measure the time evolution of its diameter for different grains and liquids, as well as various rotation rates of the drum. Using X-ray tomography, we are able to characterize the internal structure of the granular aggregate at different times during the process. We show that the growth rate of the aggregate can be related to the transport of the liquid inside the granule and the capture of grains. We propose a model to rationalize the maximum size of the aggregate and its growth rate.

International audience; A new approach to determine the displacement field between a reference and a deformed image is introduced. The method is based on a spectral decomposition of the displacement field which is determined through a multi-scale approach. The method is tested here on an artificial example by using computer-generated images devoid of boundary effects (i.e., periodic boundary conditions are used in the image texture and displacement field). The performance of the proposed algorithm allows for the determination of the prescribed displacement field up to machine precision, for a strain field whose trace extends from -50% to 40% with a root-mean-square average of 20%, within sub-minute runs on a standard PC.