We report numerical simulations of strongly vibrated granular materials designed to mimic recent experiments performed in both the presence and the absence of gravity. The coefficient of restitution used here depends on the impact velocity by taking into account both the viscoelastic and plastic deformations of particles, occurring at low and high velocities, respectively. We show that this mod...

We investigate the free cooling of inelastic rough spheres in the presence of Coulomb friction. Depending on the coefficients of normal restitution ǫ and Coulomb friction μ, we find qualitatively different asymptotic states. For nearly complete normal restitution (ǫ close to 1) and large μ, friction does not change the cooling properties qualitatively compared to a constant coefficient of tange...

Most descriptions of collision events introduce coefficients friction and tangential restitution which vary significantly with the impact angle, in contrast independence normal coefficient this parameter. A redefinition based on idea that effects can be treated as being mutually independent, provides a satisfactory description experimental data using ‘constant’ independent angle. This friction-...

We revisit our recent contribution [2] and give two simpler proofs of the socalled Haff’s law for granular gases (with non-necessarily constant restitution coefficient). The first proof is based upon the use of entropy and asserts that Haff’s law holds whenever the initial datum is of finite entropy. The second proof uses only the moments of the solutions and holds in some weakly inelasticity r...

this paper presents an accurate differential global positioning system (dgps) using multi-layered neural networks (nns) based on the back propagation (bp) and imperialistic competition algorithm (ica) in order to predict the dgps corrections for accurate positioning. simulation results allowed us to optimize the nn performance in term of residual mean square error. we compare results obtained b...

Restitution, the characteristic shortening of action potential duration (APD) with increased heart rate, has been studied extensively because of its purported link to the onset of fibrillation. Restitution is often represented in the form of mapping models where APD is a function of previous diastolic intervals (DIs) and/or APDs, A(n+1)=F(D(n),A(n),D(n-1),A(n-1),...), where A(n+1) is the APD fo...

We develop in this paper the first systematic treatment of the homogeneous Boltzmann equation for granular gases with non constant restitution coefficient, generalizing a large number of the results obtained recently for homogeneous granular gases with constant restitution coefficient to a broader class of physical restitution coefficients that depend on the collision impact velocity. Our analy...

Upper bounds on Newton’s, Poisson’s, and energetic coefficients of normal restitution for the frictional impact of rigid pendulum against a fixed surface are derived, demonstrating that the upper bound on Newton’s coefficient is smaller than 1, while the upper bound on Poisson’s coefficient is greater than 1. The upper bound on the energetic coefficient of restitution, which is a geometric mean...

A beat-to-beat alternation in the action potential duration (APD) of myocytes, i.e. alternans, is believed to be a direct precursor of ventricular fibrillation in the whole heart. A common approach for the prediction of alternans is to construct the restitution curve, which is the nonlinear functional relationship between the APD and the preceding diastolic interval (DI). It was proposed that a...

Rapid repair by cell migration, a process called "restitution", is essential for wound healing of mucous epithelia. Here, an established in vitro model for restitution, i.e., migration of the non-transformed intestinal epithelial cell line IEC-18 after scratch wounding, was investigated. This cell line is also known for its retained differentiation potential. The aim of this study was to test b...