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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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Simulating Quantum Computers and Using Quantum Computers for Simulation.
Abstract not provided.
Using Computer Simulations to Select Simulants for Capture of Chemical Warfare Agents in Nanoporous Materials.
Abstract not provided.
Computer Simulations of Entangled Polymer Melts: From Segmental Dynamics to Viscoelastic Response.
Abstract not provided.
A Framework for End-to-End Computation Simulation Credibility Workflow.
Abstract not provided.
Characterizing Material Emissivity Uncertainty in Fire Environments for Computational Simulation.
Abstract not provided.
The Role of Workflows in Credible High Consequence Computational Simulation.
Abstract not provided.
Atomistic computer simulations of dissolution of inorganic glasses.
Abstract not provided.
Fission Product Diffusion in Silicon Carbide: As Revealed by Computer Simulations and Experimental Measurements
The diffusion and release of fission products through silicon carbide in the tri-structural isotropic (TRISO) fuel particles remain unsolved for decades. The underlying mechanism is quite challenging to be determined. To help unveil the mysterious story, the current work applies molecular dynamics method to show the stability of silver, palladium, ruthenium and iodine as an interstitial and their atomic diffusion along coincident site lattice (CSL) boundary, especially ?3 grain boundary (GB). The major finding presents a much faster diffusion along GB than in bulk for all elements considered. The reasonably close estimate to experiments and simulations where available has confirmed the important role of grain boundary diffusion of Ag and Pd in SiC. However, the discrepancy addressed in Ag with measurements from fuel studies suggest a more complicated mechanism, which might be in correlation with high energy grain boundaries or the presence of crack. The subsequent characterization of Ru and I distribution in SiC-PyC-SiC diffusion couples, which have been ion irradiated at 900?C to 10 dpa and 20 dpa, has performed by secondary ion mass spectrometry (SIMS) analysis. The experiment measurements correlate well with the grain boundary diffusion by simulation, which provide further evidences that the grain boundary diffusion cannot be neglected once the fission products are accessible at the grain boundary.
Computational Simulation of Coupled Poromechanical Processes in Deformable Porous Media.
Abstract not provided.
A Suite of Thermodynamic and Transport Properties for Computational Simulations with Hydrogen Isotopes.
Abstract not provided.
Analyzing Hail Impacts on PV Modules Using Computational Simulation.
Abstract not provided.
Computer Simulations of a Rectangular,Sinusoidally Corrugated, 220 GHz Slow-Wave Structure with Path to its 3D-Printing and "Cold" Electromagnetic Analysis
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Tolerance Analysis Through Computational Imaging Simulations.
Abstract not provided.
Application of recursive manipulator dynamics to hybrid software/hardware simulation
Computer simulations of robotic mechanisms have traditionally solved the dynamic equations of motion for an N degree of freedom manipulator by formulating an N dimensional matrix equation combining the accelerations and torques (forces) for all joints. The use of an alternative formulation that is strictly recursive is described. The dynamic solution proceeds on a joint by joint basis, so it is possible to perform inverse dynamics at arbitrary joints. The dynamic formulation is generalized with respect to both rotational and translational joints, and it is also directly extendable to branched manipulator chains. A hardware substitution test is described in which a servo drive motor was integrated with a simulated manipulator arm. The form of the dynamic equation permits calculation of acceleration given torque or vice versa. Computing torque as a function of acceleration is required for the hybrid software/hardware simulation test described. For this test, a joint servo motor is controlled in conjunction with the simulation, and the dynamic torque on the servo motor is provided by a load motor on a common driveshaft.
Long-Range Dispersion Governs the Behavior of Near-Critical Fluids: Universal Scaling and Implications for Accurate Molecular Simulation
Computer simulations of near-critical and supercritical fluids often deviate from experimental results, a discrepancy commonly attributed to force-field resolutions and inaccuracies. We demonstrate that these errors primarily stem from using finite cutoff schemes for dispersion interactions, which become effectively long-range as the correlation length grows near the critical point. By employing the smooth particle-mesh Ewald method to account for full long-range dispersion, we show that coarse-grained models can also achieve high quantitative accuracy for n-undecane and propylbenzene. This approach enables the precise determination of density fluctuations and correlation lengths, which exhibit universal critical scaling and depend on the molecular size and shape. Our findings resolve a longstanding debate in molecular simulations of near-critical fluids, establishing that capturing long-wavelength fluctuations is essential for bridging the gap between the microscopic behavior and macroscopic critical phenomena.