Résumé : Romain Bey : Line tension measurement in Molecular dynamics using Virial equation
Gibbs introduced the concept of line tension as the 1D equivalent of pressure (in 3D) or surface tension (in 2D). Due to the lack of understanding of the physical behaviour and origin of line tension, it has long been used as a fitting parameter, both in experiments and simulations. Values of 10^-5 to 10^-12 Jm^-1 have been published, being either positive or negative. We aim at assessing the validity of this continuous mean-field description at the molecular scale, and at giving some insight in the physics of the triple line.
We have developed a new approach in molecular dynamics, based on anisotropic Virial equation in periodic systems. Virial equation is a molecular expression of thermodynamic forces applied on simulation box’s dimensions. Comparing these forces to Gibbs modeling of volume, surface and line components enables us to assess the validity of this description at the nanoscale. It is found to hold down to 1nm confinement, and line tension values we measure are of the order of 10^-12 J*m^-1.
Thomas Combriat : Trustworthy or liar : which one survives best ?
In this presentation I will a toy model trying to understand how a global cooperative or non-cooperative behavior can emerge from a population composed of trustworthy and liar individuals.
A population composed of so called "Escherichia-squirrels" roams on a 2D space where feeding spots are available , trying to get as much food as possible… When two individuals meet, they exchange informations about the feeding spots they know about…
But these informations can be false…