SEARCH · Engineering Papers
Results for “Simulations”
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.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Simulating Enhanced Methane Deliverable Capacity of Guest Responsive Pores in Intrinsically Flexible MOFs
In this work, a novel computational procedure, based on the principles of flat-histogram Monte Carlo, is developed for facile prediction of the adsorption thermodynamics of intrinsically flexible adsorbents. We then demonstrate how an accurate prediction of methane deliverable capacity in a metal–organic framework (MOF) with significant intrinsic flexibility requires use of such a method. Dynamic side chains in the framework respond to methane adsorbates and reorganize to exhibit a more conducive pore space at high adsorbate densities while simultaneously providing a less conducive pore space at low adsorbate densities. This “responsive pore” MOF achieves ~20% higher deliverable capacity than if the framework were rigid and elucidates a strategy for designing high deliverable capacity MOFs in the future.
Lagrangian-based simulations of hypervelocity impact experiments on Mars regolith proxy
Explore the source record for details and available documents.
Ultrafast, asymmetric charge transfer and slow charge recombination in porphyrin/CNT composites demonstrated by time-domain atomistic simulation
Defect-free porphyrin/CNT hybrids can maintain long-lived charge separation; porphyrins and CNTs can be used to harvest light at different wavelengths.
Comparing sulfidation kinetics of silver nanoparticles in simulated media using direct and indirect measurement methods
Reported reaction kinetics of metal nanoparticles in natural and engineered systems commonly have used proxy measurements to infer chemical transformations, but extension of these methods to complex media has proven difficult.
Coarse-grained molecular dynamics simulations of α-1,3-glucan
In this work we present a coarse-grained model for α-1,3-glucan that captures hydrogen bonding directionality and polysaccharide monomer structure.
A high-pressure induced stable phase of Li 2 MnSiO 4 as an effective poly-anion cathode material from simulations
A novel poly-anion Li 2 MnSiO 4 material is predicted at high pressure using global crystal structure search combined with first-principles calculation, which shows great potentials as a high-performance cathode.
Self-supported branched poly(ethyleneimine) materials for CO 2 adsorption from simulated flue gas
A family of self-supported, cross-linked PEI materials is demonstrated as promising CO 2 adsorbents, displaying (i) good CO 2 capacity (ii) rapid uptake kinetics, and (iii) good stability relative to conventional supported amine adsorbents.
Dealing with High Background Rates in the STAR Heavy Flavor Tracker in Simulation Embedding Simulation into Real Events
Explore the source record for details and available documents.
From plane waves to local Gaussians for the simulation of correlated periodic systems
Here, we present a simple, robust, and black-box approach to the implementation and use of local, periodic, atom-centered Gaussian basis functions within a plane wave code, in a computationally efficient manner. The procedure outlined is based on the representation of the Gaussians within a finite bandwidth by their underlying plane wave coefficients. The core region is handled within the projected augment wave framework, by pseudizing the Gaussian functions within a cutoff radius around each nucleus, smoothing the functions so that they are faithfully represented by a plane wave basis with only moderate kinetic energy cutoff. To mitigate the effects of the basis set superposition error and incompleteness at the mean-field level introduced by the Gaussian basis, we also propose a hybrid approach, whereby the complete occupied space is first converged within a large plane wave basis, and the Gaussian basis used to construct a complementary virtual space for the application of correlated methods. We demonstrate that these pseudized Gaussians yield compact and systematically improvable spaces with an accuracy comparable to their non-pseudized Gaussian counterparts. A key advantage of the described method is its ability to efficiently capture and describe electronic correlation effects of weakly bound and low-dimensional systems, where plane waves are not sufficiently compact or able to be truncated without unphysical artifacts. We investigate the accuracy of the pseudized Gaussians for the water dimer interaction, neon solid, and water adsorption on a LiH surface, at the level of second-order Møller–Plesset perturbation theory.
Effect of polarization forces on carbon deposition on a non-spherical nanoparticle. Monte Carlo simulations [Effect of polarization forces on atom deposition on a non-spherical nanoparticle. Monte Carlo simulations]
Trajectories of a polarizable species (atoms or molecules) in the vicinity of a negatively charged nanoparticle (at a floating potential) are considered. The atoms are pulled into regions of strong electric field by polarization forces. The polarization increases the deposition rate of the atoms and molecules at the nanoparticle. The effect of the non-spherical shape of the nanoparticle is investigated by the Monte Carlo method. The shape of the non-spherical nanoparticle is approximated by an ellipsoid. The total deposition rate and its flux density distribution along the nanoparticle surface are calculated. As a result, it is shown that the flux density is not uniform along the surface. It is maximal at the nanoparticle tips.
Using the Pagosa SURF Model to Simulate Fragment Impact on Energetic Materials for Safety Applications
Explore the source record for details and available documents.
Grouping techniques for large-scale cluster dynamics simulations of reaction diffusion processes
Not provided.
Lattice Boltzmann accelerated direct simulation Monte Carlo for dilute gas flow simulations
Not provided.