Comparison between hydroxyapatite/soapstone and hydroxyapatite/reduced graphene oxide composite coatings: Synthesis and property improvement.

Economic viability and eco-friendliness are important characteristics that make implants available to the population in a sustainable way. In this work, we evaluate the performance of a low-cost, widely available, and eco-friendly material (talc from soapstone) relative to reduced graphene oxide as reinforcement to brittle hydroxyapatite coatings. We employ a low-cost and straightforward technique, electrodeposition, to deposit the composite coatings on the titanium substrate.

Soliton instability and fold formation in laterally compressed graphene.

We investigate-through simulations and analytical calculations-the consequences of uniaxial lateral compression applied to the upper layer of multilayer graphene. The simulations of compressed graphene show that strains larger than 2.8% induce soliton-like deformations that further develop into large, mobile folds.

Core-softened fluids, water-like anomalies, and the liquid-liquid critical points.

Molecular dynamics simulations are used to examine the relationship between water-like anomalies and the liquid-liquid critical point in a family of model fluids with multi-Gaussian, core-softened pair interactions. The core-softened pair interactions have two length scales, such that the longer length scale associated with a shallow, attractive well is kept constant while the shorter length scale associated with the repulsive shoulder is varied from an inflection point to a minimum of progressively increasing depth. The maximum depth of the shoulder well is chosen so that the resulting potential reproduces the oxygen-oxygen radial distribution function of the ST4 model of water.

Effects of the attractive interactions in the thermodynamic, dynamic, and structural anomalies of a two length scale potential.

Using molecular dynamic simulations, we study a system of particles interacting through a continuous core-softened potentials consisting of a hard core, a shoulder at closest distances, and an attractive well at further distance. We obtain the pressure-temperature phase diagram of this system for various depths of the tunable attractive well. Since this is a two length scale potential, density, diffusion, and structural anomalies are expected.

Entropy, diffusivity and the energy landscape of a waterlike fluid.

Molecular dynamics simulations and instantaneous normal mode (INM) analysis of a fluid with core-softened pair interactions and waterlike liquid-state anomalies are performed to obtain an understanding of the relationship between thermodynamics, transport properties, and the potential energy landscape. Rosenfeld scaling of diffusivities with the thermodynamic excess and pair correlation entropy is demonstrated for this model. The INM spectra are shown to carry information about the dynamical consequences of the interplay between length scales characteristic of anomalous fluids, such as bimodality of the real and imaginary branches of the frequency distribution.

Liquid crystal phase and waterlike anomalies in a core-softened shoulder-dumbbells system.

Using molecular dynamics we investigate the thermodynamics, dynamics, and structure of 250 diatomic molecules interacting by a core-softened potential. This system exhibits thermodynamic, dynamic, and structural anomalies: a maximum in density-temperature plane at constant pressure and maximum and minimum points in the diffusivity and translational order parameter against density at constant temperature. Starting with very dense systems and decreasing density the mobility at low temperatures first increases, reaches a maximum, then decreases, reaches a minimum and finally increases.

Waterlike hierarchy of anomalies in a continuous spherical shouldered potential.

We investigate by molecular dynamics simulations a continuous isotropic core-softened potential with attractive well in three dimensions, introduced by Franzese [J. Mol. Liq.

Structural anomalies for a three dimensional isotropic core-softened potential.

Using molecular dynamics simulations we investigate the structure of a system of particles interacting through a continuous core-softened interparticle potential. We found for the translational order parameter t a local maximum at a density rho(t-max) and a local minimum at rho(t-min)>rho(t-max). Between rho(t-max) and rho(t-min), the t parameter anomalously decreases upon increasing pressure.

Thermodynamic and dynamic anomalies for a three-dimensional isotropic core-softened potential.

Using molecular-dynamics simulations and integral equations (Rogers-Young, Percus-Yevick, and hypernetted chain closures) we investigate the thermodynamics of particles interacting with continuous core-softened intermolecular potential. Dynamic properties are also analyzed by the simulations. We show that, for a chosen shape of the potential, the density, at constant pressure, has a maximum for a certain temperature.