arXiv subjects

Daniele Savio

Publications and source records attributed to Daniele Savio.

2 recordsLinked to original sources

arXiv2019

Structural and elastic properties of amorphous carbon from simulated quenching at low rates

We generate representative structural models of amorphous carbon (a-C) from constant-volume quenching from the liquid with subsequent relaxation of internal stresses in molecular dynamics simulations using empirical and machine-learning interatomic potentials. By varying volume and quench rate we generate structures with a range of density and amorphous morphologies. We find that all a-C samples show a universal relationship between hybridization, bulk modulus and density despite having distinct cohesive energies. Differences in cohesive energy are traced back to slight changes in the distribution of bond-angles that will likely affect thermal stability of these structures.

cond-mat.mtrl-sci↗

arXiv2019

A non-empirical free volume viscosity model for alkane lubricants under severe pressures

Viscosities $η$ and diffusion coefficients $D_s$ of linear and branched alkanes at high pressures $P$$<$0.7 GPa and temperatures $T$=500-600 K are calculated by equilibrium molecular dynamics. Combining Stokes-Einstein, free volume and random walk concepts results in an accurate viscosity model $η(D_s(P,T))$ for the considered P and T. All model parameters (hydrodynamic radius, random walk step size and attempt frequency) are defined as microscopic ensemble averages and extracted from EMD simulations rendering $η(D_s(P,T))$ a parameter-free predictor for lubrication simulations.

physics.comp-ph↗