A three-dimensional, transient model is developed for studying heat transfer, fluid flow, and mass transfer the case of a single-pass laser surface alloying process. The coupled momentum, energy, species conservation equations are solved using finite volume procedure. Phase change processes modeled fixed-grid enthalpy-porosity technique, which capable predicting continuously evolving solid-liquid interface. three-dimensional able to predict concentration distribution inside molten pool...

We study melting of a face-centered crystalline solid consisting polydisperse Lennard-Jones spheres with Gaussian polydispersity in size. The phase diagram reproduces the existence nearly temperature invariant terminal (δ(t) =/~ 0.11), no signature reentrant melting. absence can be attributed to influence attractive part potential upon find that at fractional density change approaches zero, which seems arise from vanishingly small compressibility disordered phase. At constant and volume...

In experimental and theoretical studies of glass transition phenomena, one often finds a sharp crossover in dynamical properties at temperature Tcr. A bifurcation relaxation spectrum is also observed TB≈Tcr; both lie significantly above the temperature. order to better understand these we introduce new model glass-forming liquids, binary mixture prolate oblate ellipsoids. This system exhibits thermodynamic dynamic anomalies, such as specific heat jump during heating variation thermal...

An energy landscape view of phase separation and nonideality in binary mixtures is developed by exploring their potential (PEL) as functions temperature composition. We employ molecular dynamics simulations to study a model that promotes structure breaking the solute-solvent parent liquid, at low temperatures. The PEL system captures distribution inherent structures (IS) obtained removing kinetic (including intermolecular vibrations). broader for liquid than making demonstrates larger role...

Aqueous binary mixtures often exhibit dramatic departure from the predicted hydrodynamic behavior when transport properties are plotted against composition. We show by inherent structure (IS) analysis that this sharp composition dependent breakdown of Stokes–Einstein relation can be attributed to non-monotonic variation in average energy these mixtures. Further IS reveals existence a unique ground state, stabilized both formation an optimum number H-bonds and favorable hydrophobic...

Amphiphilic molecules such as dimethyl sulfoxide (DMSO) and its aqueous binary mixtures exhibit pronounced nonideality in composition dependence of several static dynamic properties. We carry out detailed molecular dynamics simulations to calculate various properties including viscosity the mixture combine results with a mode coupling theory analysis show that this can be attributed local structures are stable on short time scale but transient long maintain large homogeneity solution....

A systematic procedure is outlined for scaling analysis of momentum and heat transfer in gas tungsten arc weld pools. With suitable selections non-dimensionalised parameters, the governing equations coupled with appropriate boundary conditions are first scaled, relative significance various terms appearing them analysed accordingly. The then used to predict orders magnitude some important quantities, such as velocity scale at top surface, layer thickness, maximum temperature increase pool,...

We study by computer simulations, and theory, the coupled rotational translational dynamics of three important linear diatomic molecules, namely, carbon monoxide (CO), nitric oxide (NO), cyanide ion (CN-) in water. Translational diffusion these molecules is found to be strongly their own which, turn, are similar motions surrounding In particular, we find that orientational jump play an role all cases. While CO NO show features, CN- exhibits certain differences. Our results agree well with...

We consider a new class of model systems to study systematically the role molecular shape in transport properties dense liquids. Our is liquid binary mixture where both molecules are non-spherical and characterized by collection parameters. Although real world most non-spherical, only limited number theoretical studies exist on effects shapes hardly any have addressed validity hydrodynamic predictions rotational translational diffusion these In this work, we consisting prolate oblate (80:20...

We study microscopic aspects of initial phase separation through atomistic molecular dynamics simulation a structure breaking liquid binary mixture. find that the kinetics in fluid mixture model system can indeed be unusual. It fast, with crossover from pronounced exponential to non-exponential and non-linear dynamics. An important outcome this work is quantification time scales involved at an early stage. The complete within ∼100 ps. involves aggregation small droplets form rapidly after...

A universal dynamical crossover temperature, Tcr, in glassy liquids, associated with the {\alpha}-\b{eta} bifurcation TB, has been observed dielectric spectroscopy and other experiments. Tcr lies significantly above glass transition temperature. Here, we introduce a new class of glass-forming binary mixtures prolate oblate ellipsoids. This model system exhibits sharp thermodynamic dynamic anomalies, such as specific heat jump during heating variation thermal expansion coefficient around...

It is commonly believed that melting occurs when mean square displacement (MSD) of a particle crystalline solid exceeds threshold value. This known as the Lindemann criterion, first introduced in year 1910 by Lindemann. However, Chakravarty et al. demonstrated this common wisdom inadequate because MSD at can be temperature dependent pressure also allowed to vary along coexistence line phase diagram [Chakravarty C, Debenedetti P G and Stillinger F H 2007 J. Chem. Phys.126 204508]. We show...

In order to find a measure of the dynamical features phase separation kinetics during spinodal decomposition liquid binary mixture (like water and cyclohexane , 2,6 lutidiene or methanol cyclohexane), we study both initial fast exponential-like growth (the Cahn-Hilliard regime) subsequent cross-over much slower, non-exponential long time so-called scaling regime), by atomistic molecular dynamics (MD) simulation structure breaking mixture. particular, combine our MD simulations with coarse...

We use polydispersity in size as a control parameter to explore certain aspects of melting and freezing transitions system Lennard-Jones spheres. Both analytical theory computer simulations are employed establish potentially interesting relationship between observed terminal polydisperse spheres prediction the same integral equation based theoretical analysis liquid-solid transition. As we increase polydispersity, solid becomes inherently unstable because strain built up due disparity. This...

We find through computer simulations that the fractional volume change on freezing of polydisperse Lennard-Jones liquid decreases with increasing polydispersity and approaches zero near a terminal 0.11, independent temperature. The transition however remains first order at polydispersity. Average inherent structure (IS) energy crystalline phase increases nearly quadratically indices ({\delta}) marked by crossover to constant IS in amorphous phase.

Binary mixtures are known to phase separate via both nucleation and spinodal decomposition, depending on the initial composition extent of quench. Here we develop an energy landscape view separation non-ideality in binary by exploring their potential (PEL) as functions temperature composition, employing a molecular model that promotes structure breaking abilities solute-solvent parent liquid at low temperatures. PEL provides inherent (IS) system is obtained removing kinetic (including...