scholarly journals Homogeneous cooling and heating states of dilute soft-core gases under nonlinear drag

2021 ◽  
Vol 249 ◽  
pp. 04001
Author(s):  
Satoshi Takada
Keyword(s):  
Molecular Dynamics ◽  
Kinetic Theory ◽  
Velocity Distribution ◽  
Molecular Dynamics Simulations ◽  
Drag Force ◽  
Soft Core ◽  
Temperature Evolution ◽  
Theoretical Predictions ◽  
Dynamics Simulations ◽  
Good Agreement

The temperature evolution of dilute soft inertial gas-solid suspensions is theoretically analyzed when the gas particles are influenced by a nonlinear drag force from a background fluid. The kinetic theory is extended to this system, and the time evolutions of the temperature and the kurtosis of the velocity distribution are derived. Molecular dynamics simulations are also performed to check the validity of the theory, and they show good agreement with the theoretical predictions.

Size-Dependent Elasticity of Silicon Nanowires

2009 ◽  
Vol 60-61 ◽  
pp. 315-319 ◽  
Author(s):  
W.W. Zhang ◽  
Qing An Huang ◽  
H. Yu ◽  
L.B. Lu
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Silicon Nanowires ◽  
First Principles ◽  
Si Nanowires ◽  
Size Dependent ◽  
Reconstructed Surfaces ◽  
Strain Relationship ◽  
Dynamics Simulations ◽  
Good Agreement

Molecular dynamics simulations are carried out to characterize the mechanical properties of [001] and [110] oriented silicon nanowires, with the thickness ranging from 1.05nm to 3.24 nm. The nanowires are taken to have ideal surfaces and (2×1) reconstructed surfaces, respectively. A series of simulations for square cross-section Si nanowires have been performed and Young’s modulus is calculated from energy–strain relationship. The results show that the elasticity of Si nanowires is strongly depended on size and surface reconstruction. Furthermore, the physical origin of above results is analyzed, consistent with the bond loss and saturation concept. The results obtained from the molecular dynamics simulations are in good agreement with the values of first-principles. The molecular dynamics simulations combine the accuracy and efficiency.

Thermal Conductivity of Amorphous and Crystalline SiO2 Nano-Films from Molecular Dynamics Simulations

2012 ◽  
Vol 501 ◽  
pp. 64-69 ◽  
Author(s):  
Yan He ◽  
Yuan Zheng Tang ◽  
Man Ding ◽  
Lian Xiang Ma
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Film Thickness ◽  
Molecular Dynamics Simulations ◽  
Grain Morphology ◽  
Nonequilibrium Molecular Dynamics ◽  
Calculated Temperature ◽  
Dynamics Simulations ◽  
Different Thickness ◽  
Good Agreement

Normal thermal conductivity of amorphous and crystalline SiO2nano-films is calculated by nonequilibrium molecular dynamics (NEMD) simulations in the temperature range from 100 to 700K and thicknesses from 2 to 6nm. The calculated temperature and thickness dependences of thermal conductivity are in good agreement with previous literatures. In the same thickness, higher thermal conductivity is obtained for crystalline SiO2nano-films. And more importantly, for amorphous SiO2nano-films, thickness can be any direction of x, y, z-axis without effect on the normal thermal conductivity, for crystalline SiO2nano-films, the different thickness directions obtain different thermal conductivity results. The different results of amorphous and crystalline SiO2nano-films simply show that film thickness and grain morphology will cause different effects on thermal conductivity.

scholarly journals Correlation Length in Concentrated Electrolytes: Insights from All-Atom Molecular Dynamics Simulations

2019 ◽  
Author(s):  
Samuel Coles ◽  
Chanbum Park ◽  
Rohit Nikam ◽  
Matej Kanduč ◽  
Joachim Dzubiella ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Correlation Length ◽  
Salt Concentration ◽  
Scaling Law ◽  
Solvent Mixture ◽  
Scaling Exponent ◽  
Concentrated Electrolytes ◽  
Theoretical Predictions ◽  
Dynamics Simulations

<div><p>We study the correlations length of the charge-charge pair correlations in concentrated electrolyte solutions by means of all-atom, explicit-solvent molecular dynamics simulations. We investigate LiCl and NaI in water, which constitute highly soluble, prototypical salts for experiments, as well as two more complex, molecular electrolyte systems of lithium bis(trifluoromethane)sulfonimide (LiTFSI), commonly employed in electrochemical storage systems, in water and in an organic solvent mixture of dimethoxyethane (DME) and dioxolane (DOL). Our simulations support the recent experimental observations as well as theoretical predictions of a non-monotonic behavior of the correlation length with increasing salt concentration. We observe a Debye-Hückel like regime at low concentration, followed by a minimum reached when <i>d/λ<sub>D</sub></i> = 1, where <i>λ<sub>D</sub></i> is the Debye correlation length and d the effective ionic diameter, and an increasing correlation length with salt concentration in very concentrated electrolytes. As in the experiments, we find that the screening length in the concentrated regime follows a universal scaling law as a function <i>d/λ<sub>D</sub></i> for all studied salts. However, the scaling exponent is significantly lower than the experimentally measured one, and lies in the range of the theoretical predictions based on much simpler electrolyte models.</p> </div>

Neural network potential for Zr-Rh system by machine learning

2021 ◽  
Author(s):  
Kun Xie ◽  
Chong Qiao ◽  
Hong Shen ◽  
Riyi Yang ◽  
Ming Xu ◽  
...  
Keyword(s):  
Neural Network ◽  
Machine Learning ◽  
Mechanical Property ◽  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Structural Features ◽  
Ab Initio Molecular Dynamics ◽  
The Neural Network ◽  
Dynamics Simulations ◽  
Good Agreement

Abstract Zr-Rh metallic glass has enabled its many applications in vehicle parts, sports equipment and so on due to its outstanding performance in mechanical property, but the knowledge of the microstructure determining the superb mechanical property remains yet insufficient. Here, we develop a deep neural network potential of Zr-Rh system by using machine learning, which breaks the dilemma between the accuracy and efficiency in molecular dynamics simulations, and greatly improves the simulation scale in both space and time. The results show that the structural features obtained from the neural network method are in good agreement with the cases in ab initio molecular dynamics simulations. Furthermore, we build a large model of 5400 atoms to explore the influences of simulated size and cooling rate on the melt-quenching process of Zr77Rh23. Our study lays a foundation for exploring the complex structures in amorphous Zr77Rh23, which is of great significance for the design and practical application.

MOLECULAR DYNAMICS SIMULATIONS OF FURAN RESIN (POLYFURFURYL ALCOHOL): PREDICTING MECHANICAL PROPERTIES

2021 ◽  
Author(s):  
JOSH KEMPPAINEN ◽  
IVAN GALLEGOS ◽  
PRATHAMESH DESHPANDE ◽  
JACOB GISSINGER ◽  
GREGORY ODEGARD
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Acid Corrosion ◽  
Carbon Composites ◽  
Corrosion Resistant ◽  
Polyfurfuryl Alcohol ◽  
Furan Resin ◽  
Dynamics Simulations ◽  
Good Agreement

Furan resins can be used as precursor resin for Carbon-Carbon Composites but has also been used in adhesives, acid/corrosion resistant materials, and as an alternative fuel precursor [15]. This paper contains the most current understanding of the structure of furan resin and a Molecular Dynamics workflow for computationally simulating its polymerization with the 'fix bond/react' command implemented in LAMMPS. The predicted mechanical properties of the polymerized resin are in good agreement with the literature values.

Molecular dynamics simulations of n-butane and n-hexane diffusion in silicalite

1995 ◽  
Vol 448 (1932) ◽  
pp. 143-160 ◽  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Guest Molecule ◽  
Measured Data ◽  
Zeolite Framework ◽  
Adsorbed Molecules ◽  
Molecule Interactions ◽  
Dynamics Simulations ◽  
And Diffusion ◽  
Good Agreement

We report molecular dynamics simulations of n-butane and n-hexane adsorbed in the zeolite silicalite. These systems have been modelled within a rigid framework approximation and a Ryckaert-Bellemans model was adopted to describe the adsorbed molecules. The parametrization due to June, Bell and Theodorou has been used to describe the host-guest molecule interactions. Long simulations (1000 ps) have been performed, modelling these systems at a variety of sorbate loadings and temperatures. These have allowed us to investigate how the presence of the zeolite framework affects the thermodynamic properties, confomational distributions and diffusion related properties of the adsorbed molecules, and their response to changes in the loading and temperature. We have obtained estimates of the diffusion coefficients and activation energies which are in good agreement with experimentally measured data.

On the Linear Temperature Dependence of Phonon Thermal Boundary Conductance in the Classical Limit

2011 ◽  
Vol 133 (7) ◽  
Author(s):  
John C. Duda ◽  
Pamela M. Norris ◽  
Patrick E. Hopkins
Keyword(s):  
Molecular Dynamics ◽  
Temperature Dependence ◽  
Molecular Dynamics Simulations ◽  
Classical Limit ◽  
Phonon Transport ◽  
Linear Temperature Dependence ◽  
Linear Temperature ◽  
Thermal Boundary Conductance ◽  
Dynamics Simulations ◽  
Good Agreement

We present a new model for predicting thermal boundary conductance in the classical limit. This model takes a different form than those of the traditionally used mismatch theories in the fact that the temperature dependence of thermal boundary conductance is driven by the phononic scattering mechanisms of the materials comprising the interface as opposed to the heat capacities of those materials. The model developed in this work assumes that a phonon on one side of an interface may not scatter at the interface itself but instead scatter with phonons in the adjacent material via the scattering processes intrinsic in the adjacent material. We find that this model is in good agreement with classical molecular dynamics simulations of phonon transport across a Si/Ge interface.

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