A theory for concentration fluctuations in binary polymer blends is developed using field-theoretic techniques. The theory provides a simple, unified framework for addressing a number of important issues. First, consideration of the fluctuation and correlation effects on different length scales leads to a clarification of three different x parameters and their interrelationship. By incorporatin...

We carried out three-dimensional simulations, with about 1.4 × 10 particles, of phase segregation in a low density binary fluid mixture, described mesoscopically by energy and momentum conserving Boltzmann-Vlasov equations. Using a combination of Direct Simulation Monte Carlo(DSMC) for the short range collisions and a version of Particle-In-Cell(PIC) evolution for the smooth long range interact...

Istituto Nazionale di Fisica Nucleare, Sezione di Firenze, Via G. Sansone 1, I-50019, Sesto F.no (Firenze), Italy Abstract We study the isospin dynamics in fragment formation within the framework of an analytical model based on the spinodal decomposition scenario. We calculate the probability to obtain fragments with given charge and neutron number, focussing on the derivation of the width of t...

The phase separation between two immiscible liquids advected by a bidimensional velocity field is investigated numerically by solving the corresponding Cahn-Hilliard equation. We study how the spinodal decomposition process depends on the presence-or absence-of Lagrangian chaos. A fully chaotic flow, in particular, limits the growth of domains, and for unequal volume fractions of the liquids, a...

A recent analysis of the charge (Z) correlations in the ∆Z− < Z > plane for Xe+Sn central collisions at 32 MeV/u has shown an enhancement in the production of equally sized fragments (low ∆Z) which was interpreted as evidence for spinodal decomposition. However the signal was weak. After a critical analysis of its robustness, we propose in this paper a new technique to build the uncorrelated yi...

Inelastic neutron-scattering spectra were measured on stoichiometric Fe0.50Cr0.50 prepared as a bodycentered-cubic bcc solid solution, and after increasing amounts of chemical unmixing on the bcc lattice induced by annealing the solid solution at 773 K. These spectra were reduced by a conventional procedure to a neutron-weighted vibrational density of states. Mössbauer spectrometry was used to ...

Using a modified Cahn-Hilliard-Cook theory for spinodal decomposition in binary mixture that exhibits both diffusion and interconversion dynamics, we derive the time-dependent structure factor concentration fluctuations. We compare obtain qualitative agreement with simulations of temporal evolution order parameter nonequilibrium Ising/lattice-gas hybrid model presence an external source forcefu...

Density fluctuations resulting from spinodal decomposition in a nonequilibrium first-order chiral phase transition are explored. We show that such instabilities generate divergent fluctuations of conserved charges along the isothermal spinodal lines appearing in the coexistence region. Thus, divergent density fluctuations could be a signal not only for the critical end point but also for the fi...

Using a novel electrochemical phase-field model, we question the common belief that LixFePO4 nanoparticles separate into Li-rich and Li-poor phases during battery discharge. For small currents, spinodal decomposition or nucleation leads to moving phase boundaries. Above a critical current density (in the Tafel regime), the spinodal disappears, and particles fill homogeneously, which may explain...

Researchers attributed the orderly arranged nanoscale phases observed in many multi-principal element alloys (MPEAs) to spinodal/spinodal-mediated phase transformation pathways. However, spinodal decomposition is not well understood multicomponent systems. Although theoretical background available, CALPHAD databases were used explore miscibility gap MPEAs. In this work, we develop a framework u...