A Monte-Carlo Study of B2 Ordering and Precipitation on a Bcc Lattice

1995 ◽  
Vol 398 ◽  
Author(s):  
M. Athènes ◽  
P. Bellon ◽  
G. Martin ◽  
F. Haider
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Binary Alloy ◽  
Monte Carlo Study ◽  
Atomic Mobility ◽  
Vacancy Mechanism ◽  
Exchange Frequency ◽  
Early Stages ◽  
Bcc Lattice ◽  
Good Agreement

ABSTRACTAtomistic Monte-Carlo simulations of precipitation and B2 ordering in a binary alloy on a BCC lattice via vacancy mechanism are presented. Evolution of simulated patterns is in good agreement with the experimentally observed morphologies. Moreover, it is observed that the very early stages of ordering are strongly dependent on atomic mobility parameters. Depending on the relative exchange frequency of vacancies with A and B atoms, two extreme regimes oiordering are identified, leading either to localized or delocalized ordering.

scholarly journals Adsorption of H2 on Penta-Octa-Penta Graphene: Grand Canonical Monte Carlo Study

2020 ◽  
Vol 6 (2) ◽  
pp. 20
Author(s):  
Maxim N. Popov ◽  
Thomas Dengg ◽  
Dominik Gehringer ◽  
David Holec
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Hydrogen Adsorption ◽  
Monte Carlo Study ◽  
Adsorption Properties ◽  
Cryogenic Temperatures ◽  
Grand Canonical Monte Carlo ◽  
New Material ◽  
Grand Canonical ◽  
Carbon Based

In this paper, we report the results of hydrogen adsorption properties of a new 2D carbon-based material, consisting of pentagons and octagons (Penta-Octa-Penta-graphene or POP-graphene), based on the Grand-Canonical Monte Carlo simulations. The new material exhibits a moderately higher gravimetric uptake at cryogenic temperatures (77 K), as compared to the regular graphene. We discuss the origin of the enhanced uptake of POP-graphene and offer a consistent explanation.

scholarly journals Universal dependence of the total number albedo of photons on the mean number of photon scatterings

2011 ◽  
Vol 26 (3) ◽  
pp. 249-253 ◽  
Author(s):  
Vladan Ljubenov ◽  
Rodoljub Simovic
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Analytic Functions ◽  
Least Squares Method ◽  
Mcnp Code ◽  
Initial Photon ◽  
Aluminum Iron ◽  
Universal Dependence ◽  
The Mean ◽  
Good Agreement

This paper presents the results of research on photon reflection from plane targets based on Monte Carlo simulations performed by the MCNP code. Five materials (water, concrete, aluminum, iron, and copper) are examined in the area of initial photon energies of up to 200 keV. The values of the total number albedo for photons dependent on the initial photon energy or the mean number of photon scatterings are calculated and graphically presented. We have shown that the values of the total number albedo for different target materials, expressed as a function of the mean number of photon scatterings, are in good agreement with each other and can be approximated by simple, universal analytic functions obtained by the least squares method. The accuracy of these analytic appoximations is confirmed by their comparison with the results of PENELOPE and FOTELP Monte Carlo codes.

scholarly journals Monte Carlo simulations of two-component drop growth by stochastic coalescence

2008 ◽  
Vol 8 (2) ◽  
pp. 7289-7313 ◽  
Author(s):  
L. Alfonso ◽  
G. B. Raga ◽  
D. Baumgardner
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Stochastic Algorithm ◽  
Aerosol Composition ◽  
Particle Charging ◽  
Two Component ◽  
Different Types ◽  
Framework Species ◽  
Stochastic Coalescence ◽  
Good Agreement

Abstract. The evolution of two-dimensional drop distributions is simulated in this study using a Monte Carlo method.~The stochastic algorithm of Gillespie (1976) for chemical reactions in the formulation proposed by Laurenzi et al. (2002) was used to simulate the kinetic behavior of the drop population. Within this framework species are defined as droplets of specific size and aerosol composition. The performance of the algorithm was checked by comparing the numerical with the analytical solutions found by Lushnikov (1975). Very good agreement was observed between the Monte Carlo simulations and the analytical solution. Simulation results are presented for bi-variate constant and hydrodynamic kernels. The algorithm can be easily extended to incorporate various properties of clouds such as including several crystal habits, different types of soluble CCN, particle charging and drop breakup.

Non-Equilibrium Critical Relaxation of Heisenberg Ferromagnets with Long-Range Correlated Defects

2012 ◽  
Vol 190 ◽  
pp. 39-42
Author(s):  
M. Medvedeva ◽  
Pavel V. Prudnikov
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Critical Behavior ◽  
Critical Exponents ◽  
Heisenberg Model ◽  
Three Dimensional ◽  
Initial State ◽  
Short Time ◽  
Theoretic Description ◽  
Good Agreement

The dynamic critical behavior of the three-dimensional Heisenberg model with longrangecorrelated disorder was studied by using short-time Monte Carlo simulations at criticality.The static and dynamic critical exponents are determined. The simulation was performed fromordered initial state. The obtained values of the exponents are in a good agreement with resultsof the field-theoretic description of the critical behavior of this model in the two-loopapproximation.

Topological defects in nematic films between planar degenerate surfaces. A Monte Carlo study

2021 ◽  
pp. 2250016
Author(s):  
Cesare Chiccoli ◽  
Paolo Pasini ◽  
Luiz Roberto Evangelista ◽  
Rodolfo Teixeira de Souza ◽  
Claudio Zannoni
Keyword(s):  
Monte Carlo ◽  
Boundary Conditions ◽  
Monte Carlo Simulations ◽  
Defect Structure ◽  
Topological Defects ◽  
Monte Carlo Study ◽  
Geometric Parameters ◽  
Molecular Organization ◽  
The One

The molecular organization of a nematic film sandwiched between two planar randomly aligned surfaces is studied by means of detailed Monte Carlo simulations. The formation as well as the evolution of topological defects induced by these particular boundary conditions are investigated. The resulting defect structure is compared with the one induced by hybrid aligned surfaces. The observation of such defects and some features of their structures can be associated with geometric parameters of the film and with properties of the confining surfaces.

On the Estimation of the Kurtosis in Directional Sea States for Freak Wave Forecasting

2011 ◽  
Vol 41 (8) ◽  
pp. 1484-1497 ◽  
Author(s):  
Nobuhito Mori ◽  
Miguel Onorato ◽  
Peter A. E. M. Janssen
Keyword(s):  
Monte Carlo ◽  
Energy Distribution ◽  
Monte Carlo Simulations ◽  
Initial Conditions ◽  
Laboratory Data ◽  
Dispersion Effect ◽  
Freak Wave ◽  
Wave Forecasting ◽  
Directional Sea States ◽  
Good Agreement

Abstract Based on Monte Carlo simulations of the nonlinear Schrödinger equation in two horizontal dimensions, the dependence of the kurtosis on the directional energy distribution of the initial conditions is examined. The parametric survey is carried out to obtain the behavior of the kurtosis as function of the Benjamin–Feir index and directional spread in directional sea states. As directional dispersion effect becomes significant, the kurtosis monotonically decreases in comparison with the unidirectional waves. A parameterization of the kurtosis estimated from directional spectra is proposed here; the error of the parameterization is at most 10%. The parameterization is verified against laboratory data, and good agreement is obtained.

scholarly journals Effective Thermal Conductivity of Spherical Particulate Nanocomposites: Comparison with Theoretical Models, Monte Carlo Simulations and Experiments

2014 ◽  
Vol 13 (03) ◽  
pp. 1450022 ◽  
Author(s):  
Hatim Machrafi ◽  
Georgy Lebon
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Theoretical Models ◽  
Irreversible Thermodynamics ◽  
Flux Vector ◽  
Heat Flux Vector ◽  
The Matrix ◽  
The Status ◽  
Independent Variable ◽  
Good Agreement

The purpose of this work is to study heat conduction in systems that are composed out of spherical micro-and nanoparticles dispersed in a bulk matrix. Special emphasis will be put on the dependence of the effective heat conductivity on various selected parameters as dimension and density of particles, interface interaction with the matrix. This is achieved by combining the effective medium approximation and extended irreversible thermodynamics, whose main feature is to elevate the heat flux vector to the status of independent variable. The model is illustrated by three examples: Silicium-Germanium, Silica-epoxy-resin and Copper-Silicium systems. Predictions of our model are in good agreement with other theoretical models, Monte-Carlo simulations and experimental data.

Kinetics of B2, DO3, and B32 ordering: Results from pair approximation calculations and Monte Carlo simulations

1994 ◽  
Vol 9 (2) ◽  
pp. 348-356 ◽  
Author(s):  
L. Anthony ◽  
B. Fultz
Keyword(s):  
Monte Carlo ◽  
Kinetic Theory ◽  
Monte Carlo Simulations ◽  
Nearest Neighbor ◽  
Pair Approximation ◽  
Probability Method ◽  
Critical Temperatures ◽  
Point Pair ◽  
Bcc Lattice ◽  
Kinetics Of

A kinetic theory of ordering based on the path probability method was implemented in the pair (Bethe) approximation and used to study the kinetics of short- and long-range ordering in alloys with equilibrium states of B2, DO3, or B32 order. The theory was developed in a superposition approximation for a vacancy mechanism on a bcc lattice with first- (1nn) and second-nearest neighbor (2nn) pair interactions. Chained 1nn conditional probabilities were used to account for the entropy of 2nn pair configurations. Monte Carlo simulations of ordering were also performed and their results compared to predictions of the pair approximation. Comparisons are also made with predictions from an earlier kinetic theory implemented in the point (Bragg-Williams) approximation. For all three calculations (point, pair, and Monte Carlo), critical temperatures for B2 and DO3 ordering are reported for different 1nn and 2nn interaction strengths. The influence of annealing temperature on the kinetic paths through the space of B2, DO3, and B32 order parameters was found to be strong when the thermodynamic preferences for the ordered states were of similar strengths. Transient states of intermediate order were also studied. A transient formation of B32 order in an AB3 alloy was found when 2nn interactions were strong, even when B32 order was neither a Richards-Allen-Cahn ground state nor a stable equilibrium state at that temperature. The formation of this transient B32 order can be argued consistently from a thermodynamic perspective. However, a second example of transient B2 order in an AB alloy with equilibrium B32 order cannot be explained by the same thermodynamic argument, and we believe that its origin is primarily kinetic.

Monte Carlo simulations of weak polyelectrolyte microgels: pH-dependence of conformation and ionization

Soft Matter ◽  
2018 ◽  
Vol 14 (20) ◽  
pp. 4087-4100 ◽  
Author(s):  
C. Hofzumahaus ◽  
P. Hebbeker ◽  
S. Schneider
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Ph Dependence ◽  
Monte Carlo Study ◽  
Swelling Behavior ◽  
Ph Dependent

A Monte Carlo study of the pH-dependent ionization and swelling behavior of weak polyelectrolyte microgels.

Sign in / Sign up

Export Citation Format

Share Document