L. Ponson | Searcharxiv

arXiv2010

Evidence of deep water penetration in silica during stress corrosion fracture

We measure the thickness of the heavy water layer trapped under the stress corrosion fracture surface of silica using neutron reflectivity experiments. We show that the penetration depth is 65-85 ångströms, suggesting the presence of a damaged zone of $\approx$ 100 ångströms extending ahead of the crack tip during its propagation. This estimate of the size of the damaged zone is compatible with other recent results.

cond-mat.mtrl-sci↗

arXiv2005

Phase transition or Maxwell's demon in Granular gas?

Dynamics of vibro-fluidised granular gas is investigated experimentally using the transfer of grains from a compartment through a horizontal slit at a given height h . It is demonstrated that the transfer rate j varies linearly with the grain number N in the box when N remains small; however j(N) becomes strongly non linear as soon as the number n of layers is larger than 0.3; dj/dN becomes negative for n>0.4.It is found also that the maximum of j(N) increases slightly with the acceleration af_ of the vibration which excites the granular gas. Using dynamical system theory, dynamics equations are written, and a critical bifurcation is found, which explains the existence of a condensation and of a phase transition. This explains how the pseudo " Maxwell's demon" works in granular gases. This experiments contradicts recent modeling . Pacs # : 5.40 ; 45.70 ; 62.20 ; 83.70.Fn

cond-mat.soft↗