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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Molecular Dynamics Simulations of Hydrogen and Nitrogen Implantation in Tungsten.
Abstract not provided.
Dynamic population balance in molecular-level simulations of hypersonic flows
This report summarizes the work towards developing stochastic weighted particle methods (SWPM) for future application in hypersonic flows. Extensive changes to Sandia’s direct simulation Monte Carlo (DSMC) solver, SPARTA (Stochastic Particle Real Time Analyzer), were made to enable the necessary particle splitting and reduction capabilities for SWPM. The results from one-dimensional Couette and Fourier flows suggest that SWPM can reproduce the correct transport for a large range of Knudsen numbers with adequate accuracy. The associated velocity and temperature profiles are in good agreement with DSMC. An issue with particle placement during particle number reduction, is identified, to which, a simple but effective solution based on minimizing the center of mass error is proposed. High Mach wheel flows are simulated using the SWPM and DSMC methods. SWPM is capable of providing nearly an order of magnitude increase in efficiency over DSMC while retaining high accuracy.
Exascale Ready Molecular Dynamics Simulations With LAMMPS; Application to Fluid Instabilities at Liquid-Vapor Coexistence
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Using Molecular Dynamics Simulations to Relate Morphology to Water and Ion Dynamics in Hydrated Polymers
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Enabling Molecular Dynamics Simulations of Helium Bubble Formation in Tritium-Containing Austenitic Stainless Steels:An Fe-Ni-Cr-H-He Interatomic Potential
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Molecular-level simulations of turbulence via the direct simulation Monte Carlo method
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Trends in Ionic Liquid Diffusion in Graphite Slit Pores from Molecular Dynamics Simulation and Machine Learning
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Entrapment of Volatile Organic Compounds in Defective UiO-66 Metal-Organic-Framework: Ab Initio Molecular Dynamics Simulations at 300K
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Molecular-level simulations of turbulent Couette flow over rough surfaces
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Entrapment of VOCs in Defective UiO-66 MOF: Ab Initio Molecular Dynamics Simulations at 300K
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Molecular-level simulations of turbulent Couette flow over a thermal-protection-system material
APS DFD 2024 presentation
Using molecular dynamics simulations to validate a new approach for determining the melting curves of materials
The Los Alamos National Laboratory (LANL), located in the state of New Mexico (United States), is one of the most iconic research centers in the world. Founded in 1943 as part of the Manhattan Project, it emerged from a global conflict and an unprecedented scientific emergency. At that time, the United States feared that Nazi Germany might develop an atomic weapon first. Under the direction of physicist J. Robert Oppenheimer, the U.S. government established a secret laboratory in an isolated region of the Los Alamos plateau, bringing together some of the greatest scientific minds of the era. This site, then known as Project Y, became the birthplace of the first atomic bomb.
Molecular Dynamics Simulations Confirm Hydrogen Bond Mediated Stability in the Engineered FAST protein [Poster]
Abstract not provided.
Machine Learning Acceleration of Molecular Dynamics Simulation: Gaussian propagator from machine-learned Hessian
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Resolving Salt-Induced Agglomeration of Laponite Suspensions Using X-ray Photon Correlation Spectroscopy and Molecular Dynamics Simulations
Linking the physics of the relaxation behavior of viscoelastic fluids as they form arrested gel states to the underlying chemical changes is essential for developing predictive controls on the properties of the suspensions. In this study, 3 wt.% laponite suspensions are studied as model systems to probe the influence of salt-induced relaxation behavior arising from the assembly of laponite nanodisks. X-ray Photon Correlation Spectroscopy (XPCS) measurements show that laponite suspensions prepared in the presence of 5 mM concentrations of CaCl2, MgCl2 and CsCl salts accelerate the formation of arrested gel states, with CaCl2 having a significant impact followed by CsCl and MgCl2 salts. The competing effects of ion size and charge on relaxation behavior are noted. For example, the relaxation times of laponite suspensions in the presence of Mg2+ ions are slower compared to Cs+ ions despite the higher charge, suggesting that cation size dominates in this scenario. The faster relaxation behavior of laponite suspensions in the presence of Ca2+ ions compared to Cs+ ions shows that a higher charge dominates the size of the ion. The trends in relaxation behavior are consistent with the cluster formation behavior of laponite suspensions and the electrostatic interactions predicted from MD simulations. Charge balance is achieved by the intercalation of the cations at the negatively charged surfaces of laponite suspensions. These studies show that the arrested gel state of laponite suspensions is accelerated in the presence of salts, with ion sizes and charges having a competing effect on relaxation behavior.