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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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1,151 records · Page 64
All sourcesNASA NTRSDOE OSTI
DOE OSTI2012

An Evaluation of Molecular Dynamics Performance on the Hybrid Cray XK6 Supercomputer

For many years, the drive towards computational physics studies that match the size and time-scales of experiment has been fueled by increases in processor and interconnect performance that could be exploited with relatively little modification to existing codes. Engineering and electrical power constraints have disrupted this trend, requiring more drastic changes to both hardware and software solutions. Here, we present details of the Cray XK6 architecture that achieves increased performance with the use of GPU accelerators. We review software development efforts in the LAMMPS molecular dynamics package that have been implemented in order to utilize hybrid high performance computers. We present benchmark results for solid-state, biological, and mesoscopic systems and discuss some challenges for utilizing hybrid systems. We present some early work in improving application performance on the XK6 and performance results for the simulation of liquid copper nanostructures with the embedded atom method.

43 PARTICLE ACCELERATORS↗
DOE OSTI2012

Signatures of the Rayleigh-Plateau Instability Revealed by Imposing Synthetic Perturbations on Nanometer Liquid Metals on Substrates

Fluid jets destabilize into droplets according to the well known Rayleigh Plateau (RP) instability. The applicability of the RP model to a nanoscale liquid metal supported on a substrate (a so called rivulet) was investigated using molecular dynamics (MD) simulations as it has important implications for nanoscale materials assembly. Stochastic fluctuations were found to affect rivulet stability and dynamics when compared with microscopic predictions of rivulet break up; here a broad and delayed distribution of break up times was observed. Yet, hallmark characteristics of the RP theory were observed; (1) a critical wavelength demarcating stability, (2) stable and unstable growth modes and (3) neck formation induced by axial pressure gradients. Notably, MD simulations implementing synthetic perturbations, yielded significantly reduced dispersion in the final nanodroplet spacing and clearly revealed the underlying physics driving rivulet break up.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Evaluation of Installation Time for SMASHmount by SMASHsolar

The Department of Energy SunShot Incubator program provides early-stage assistance to help startup companies cross technological barriers to commercialization while encouraging private sector investment. The SunShot Incubator program aims to shorten the time it takes for a young business or company to develop an innovative product concept and make it commercially available, which includes product prototyping, deployment, and, potentially, manufacturing. SMASHsolar was selected as an Incubator awardee to develop a simple, snap-together, module-integrated photovoltaic (PV) mounting system in attempts to dramatically reduce the time, effort and skill needed to install rooftop solar. In support of this award, the National Renewable Energy Laboratory worked with SMASHsolar to develop a procedure for evaluating the installation time required for the SMASHmount system vs. widely-available rail systems. Amongst several installations, NREL measured the following installation times, subject to the qualifications and conditions described later in this report. NREL found that the SMASHsolar SMASHmount system was installed between 15% and 37% faster than tested competing systems after one or two installations of the system.

14 SOLAR ENERGY↗
DOE OSTI2020

PV Storm Hardening Costs

While solar arrays often survive severe weather events, systems are occasionally compromised and left unable to provide power. For PV systems to act as resilient power providers, they must remain operational. Building a system that is more likely to survive a storm comes at a cost, though. Previous efforts have identified various system measures and practices that can increase the likelihood of a PV system surviving a severe weather event. But what is the cost premium for a storm hardened PV system? This report provides initial estimates for the up-front cost premiums for various methods of storm hardening PV systems.

14 SOLAR ENERGY↗
DOE OSTI2020

PV High Wind User Test Facility

The creation of a PV high wind test facility at the NREL Flatirons Campus that will enable private and public research efforts aimed at storm hardening PV systems. The facility will be instrumented to monitor effects of high wind conditions on modules and other array components. These in-field tests will coordinate with flow models, wind tunnel testing, validation of PV aeroelastic design codes, and post-testing module and system component analysis.

14 SOLAR ENERGY↗
DOE OSTI2020

Helium Ion Microscopy

Nanotechnology research led to the development of various instruments to be used for imaging or fabrication. The helium ion microscope (HIM) became available in 2006 but quickly gained popularity. Its unique gas field ion source enables high-resolution imaging, nanofabrication, direct write, and the recent combination with a secondary ion mass spectrometer offers chemical imaging with ~15 nm resolution. Particularly attractive are the small interaction volume of He and Ne (the two gases offered), small beam spot size, and a moderate sputtering rate. Additionally, the HIM is an excellent imaging tool for insulating samples in soft, polymeric, and biological materials. It can be expected that helium ion microscopy will continue to have a strong influence on broad range of scientific disciplines, including chemistry, materials science, and biology.This chapter aims at providing an overview of the current status of HIM for imaging, analysis, and nanofabrication. It introduces the reader to key components of the instrument, theoretical background, and latest results in the areas of imaging, material fabrication, and chemical analysis capabilities of helium ion microscopy.

Belianinov, Alex↗