Research Engineer PhD
- Research Engineer at the Laboratory Reactions and Process Engineering since 1992.
- Supervisor of the team “Product Engineering” of the LRGP since 2016.
- Supervisor of 10 post-doctorates, 12 PhD, 7 pharmacy and dentistry thesis.
- 80 publications – 8 books chapters – 99 conference proceedings.
- 26 invited conferences – 13 oral communications – 12 general public conferences.
- Ph.D. Thesis prize of the Institut National Polytechnique de Lorraine (INPL) in 2004.
- Crystal prize of the National Centre for Scientific Research (CNRS) in 2009.
- Grand Prix of the French Group of Rheology (Maurice Couette prize) in 2016.
- Member of the French Group of Rheology (GFR) since 1994.
• Member or the “Académie Lorraine des Sciences” since 2010.
Powders and granular media are omnipresent in our environment and have for centuries been of considerable socio-economic interest in many industrial areas such as cosmetics, pharmaceuticals, agri-food or building materials. In industrial processes involving powdered media, these undergo many unit operations (separation, agitation, mixing, shaping) and are subjected to resulting mechanical solicitations (flow, deformation, compression). Rheology being the “science of deformation and flow of matter”, it is clear that it can only be beneficial for the control of an industrial process involving granular materials, whether for the dimensioning of chemical engineering plants or the formulation of products. Unfortunately, powders are macroscopic, out of equilibrium and very dissipative media, insensitive to thermal Brownian motion and very sensitive to ambient humidity. As a consequence, even if many characterization techniques are currently available, from a practical point of view, it is still difficult to obtain reproducible measurements and, from a theoretical point of view, it is difficult to interpret the results of these measurements.
In this context, we have designed “powder rheometer” allowing to control humidity and to reproduce the analog of a Brownian motion within samples by subjecting them to vibrations. This results in two major advantages: from an experimental point of view, the sensitivity and reproducibility of the measurements are considerably improved and from a theoretical point of view it becomes possible to apply the methods of statistical physics. This led us to develop a structural model, the “quicksand castle model” allowing to describe and interpret, qualitatively and quantitatively, the rheological behaviour of dry, wet or liquid-saturated granular systems. Consequently, it becomes possible to relate the macroscopic rheological properties of powders of very varied natures to the local structural characteristics of the grains of which they are composed. This methodology can therefore be a valuable characterisation and formulation tool in cosmetics, food, building materials or phosphate industries to name but a few.
Keywords : rheology, powders, modelling, formulation, product engineering