Biomedical subjects

F Restagno

Publications and source records attributed to F Restagno.

2 recordsLinked to original sources

PubMed2002

Adhesion between weakly rough beads.

Cohesion effects are of prime importance in powders and granular media, and they are strongly affected by the roughness of the grain surface. We report measurements of the adhesion force between surfaces of Pyrex having a nanometric roughness, with a surface force apparatus. The two surfaces are immersed in liquid n-dodecane. The adhesion force measured is much smaller than expected in the case of smooth surfaces. We find that the adhesion force depends on the maximal load that has been applied on the surfaces, but does not depend on the time during which they have been in contact. We propose a model of plastic deformation of the small asperities in a macroscopic Hertz contact which is in good agreement with the experimental data.

Journal Article↗

PubMed2000

Metastability and nucleation in capillary condensation

This paper is devoted to thermally activated dynamics of capillary condensation. On the basis of a simple model we identify the critical nucleus involved in the transition mechanism and calculate the nucleation barrier from which we obtain information on the nucleation time. Close to the condensation point, the theory predicts extremely large energy barriers leading to strong metastabilities, long time dependencies, and large hysteresis in agreement with experimental observations in mesoporous media. The validity of the model is assessed using a numerical simulation of a time-dependent Ginzburg-Landau model for the confined system.

Journal Article↗