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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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At least 361 records · Page 20

Investigating In-Situ Fracture Behaviors of Polymer Pipeline Materials in Hydrogen and Hydrogen-Methane Blended Gas Environments

To reduce carbon emissions, the US natural gas infrastructure is seen as a primary solution for efficiently transporting hydrogen gas. Blending hydrogen gas with natural gas and transporting it across a national infrastructure could save significant infrastructure costs. To properly operate the infrastructure under the new gas system, it is critical to understand material compatibility with hydrogen under various conditions. The Blended Gas CRADA, a Hyblend project, is established to determine the material compatibility of existing natural gas pipes with hydrogen gas. In this study, we investigate the in-plane fracture behaviors of MDPEMarlex and HDPEGDB exposed to hydrogen and hydrogen-methane blended gas. Single-edge notch bending geometry is used. All tests are executed in-situ with the gas environment. The experimental results show a significant effect of the gas environment on HDPEGDB specimens, reducing 5% (H2) to 42% (Blended gas) of specific fracture energy compared to non-aged specimens. For the MDPEMarlex, the effects of the gas environment have increased the specific fracture energy by 10% (H2) to 15% (Blended gas). Fracture surfaces of the tested samples are observed using an electronic microscope. The in-plane fracture surface of HDPEGDB shows a pronounced dimple fracture pattern after exposure to hydrogen and blended gas. The expanded fracture pattern contributes to lower the specific fracture energy. These observations provide critical information for validating polymer pipeline materials when interact with hydrogen and hydrogen-blend gas.

Ko, Seunghyun↗

LLaMP v0.1.0

Reducing hallucination of Large Language Models (LLMs) is imperative for use in the sciences, where reliability and reproducibility are crucial. However, LLMs inherently lack long-term memory, making it a nontrivial, ad hoc, and inevitably biased task to fine-tune them on domain-specific literature and data. LLaMP is a multimodal retrieval-augmented generation (RAG) framework of hierarchical reasoning and acting (ReAct) agents that can dynamically and recursively interact with Materials Project to ground large language models on high-fidelity materials informatics.

Riebesell, Janosh [Lawrence Berkeley National Labo↗

Pressure Simulations for the EIC Interaction Region

Background detector rates in the Electron Ion Collider depend in part on the pressure in the interaction region. Materials choice, synchrotron radiation induced desorption, conditioning time and pumping configuration all affect the pressure in the system. Simulations of the region using Synrad and Molflow+ coupled simulation codes will be presented for various configruations and conditioning times.

Stutzman, M. L.↗

MontePy: a Python library for reading, editing, and writing MCNP input files.

The Monte Carlo N-Particle (MCNP) radiation transport code is a highly capable and accurate code with a long legacy. MCNP uses the Monte Carlo simulation process to simulate the path of particles (e.g., neutrons, photons, charged particles, etc.), and their interaction with materials. It is widely used in nuclear engineering, high-energy physics, and other fields. Its origins in the mid-twentieth century predate many modern software conventions. MCNP users provide an input file to MCNP, which it then uses to create an internal representation of the simulation problem. These input files originally had to be stored as punchcard decks, and the user manual still uses the terminology of cards and decks, despite moving beyond punchcards. MCNP predates nearly all modern human readable markup or data serialization languages, such as the extensible Markup Language (XML), the Standard Generalized Markup Language (SGML), YAML (YAML Ain’t Markup Language), and Javascript Object Notation (JSON). Due to this, MCNP uses an entirely custom defined syntax language for its input, making off-the-shelf libraries for XML, YAML, and JSON impossible to use for scripting various operations on MCNP input files (Kulesza et al., 2022).

97 - MATHEMATICS AND COMPUTING↗

Deciphering the PMI Surface Chemistry of Lithium-Based PFCs and its Effects on High Performance Plasmas in NSTX

The primary aims or objectives of the proposed work here focus on the dynamic measurement (Illinois PI Allain) and atomistic-based multi-scale computational atomistic simulations (UTK PI: Wirth) of: 1) lithium coatings with re-deposited hydrogenated carbon surfaces and high-Z substrates, 2) lithium coatings on boronized ATJ graphite surfaces and high-Z substrates and 3) lithium coatings on ATJ graphite and high-Z substrates with variation in temperature. Three main primary tasks are proposed to address each of the primary objectives listed above: 1) dynamic in-situ irradiation with D+, He+ species of lithium coatings with variation in interface substrate morphology (e.g. smooth vs rough, fuzz vs nanostructured); 2) validation and coupling with multi-scale computational simulations connecting the irradiated surface to the plasma edge; 3) extrapolation to long-pulse conditions (e.g. function of flux vs fluence studies). In primary objective #3, temperature-based effects will be studied to evaluate three primary mechanisms: a) D uptake and recycling, b) erosion, and c) surface melting and evaporation as a function of substrate morphology and chemistry.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

Advanced grazing-emission X-ray fluorescence spectroscopy with small-angle neutron scattering for in-vivo surface composition and defect/morphology surface evolution in tokamak PMI

The dynamic and extreme conditions of thermonuclear fusion tokamak plasmas render material surfaces almost impossible to examine in real-time, surface-sensitive conditions. However, combining particle-probe techniques that are not charge-state dependent open the possibilities of in-vivo diagnosis of the plasma-material interface. The reconstituted surfaces of plasma-facing components ranging from first-wall to divertor-component regions in the device vary depending on the complex plasma transport characteristics of the device. For example, in ITER it is predicted that fluxes of the order 10 22 to 10 24 and incident charged-particle energies of 100’s to 1000’s of eV will reach the surface while in the divertor regions within the private-flux and near the inner and outer-strike points would vary from a few eV to 100’s of eV governed by the complex Chodura magnetic sheath dynamics. This means that the penetration range of most charged-particle fluxes would range between 1-100’s of nm (e.g. for fuel particles of D and T and He).

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

Ex-Situ Surface Characterization Studies and Boundary Plasma Diagnostic Development for DIII-D (Final Report)

This report details the accomplishments for award DE-SC0016318, which sponsored collaborative research activities between the University of Tennessee-Knoxville and the DIII-D experiment at General Atomics, led by the PI (Donovan), which officially began on August 1, 2016 and ended July 31, 2020. Though the official start date for the award was August 1, 2016, the PI had already initiated collaborative activities with DIII-D during 2015 supported by internal UTK start-up funds utilized by the PI. This prior work enabled UTK to have a substantial role in the June 2016 Metal Rings Campaign (MRC). The DOE funds then provided the opportunity to expand the UTK team with funding for students and a postdoc to perform ex-situ analysis on the wide array of samples exposed during the MRC and develop more sophisticated analysis tools and interpretive modeling techniques.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

Cooperative Education

M-3 Focused Experiments is a group at Los Alamos National Lab (LANL) and is under the Dynamic Experiments Division. Their work surrounds the diagnostics and study of explosives and their interaction with materials. The data collected is used to better understand the erratic nature of explosions and high velocity projectiles. Through better comprehension of this science, the overall national security will be improved while innovations are made along the way. Despite the strong drive for research and development, the lab holds safety above all else and constantly updates procedures to protect LANL employees and their environment. At any time, there are multiple projects going on at once within the team and I am tasked with assisting the Firing Site Leaders and various research diagnosticians in any way possible with the setup, testing, and execution of data collection for each experiment. Such data includes velocity, fragmentation characteristics, and the spread of energy across the material to name a few. During my summer employment with the lab, my main goal is to maintain a questioning attitude and learn as much possible about the research and development side of science and engineering. Throughout the duration of the Co-op, many experiments will take place at specially designed firing sites which is where I will be spending most of my time.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗

In-situ Laser Induced Breakdown Spectroscopy Measurements in PISCES-A

The goal of the project was to develop a Laser Induced Breakdown Spectroscopy (LIBS) diagnostic that could be employed during the plasma exposure of targets in the PISCES-A linear plasma device to interrogate the surface as the plasma exposure progressed. The objectives of the measurements were twofold; first, to measure in real-time the composition of elements in the near surface ablated zone to enable a tool that could be used to validate material migration models of eroded material, and second, to measure the plasma fuel contained in the ablated surface to determine the static and dynamic inventory of gas in a target during the plasma exposure. The LIBS diagnostic was successfully deployed on PISCES-A and measured both elemental composition and gas accumulation in the near-surface ablated layer during plasma operations.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

Scrape-off layer stability, turbulence and transport in MAST-U (Final Report)

U.S. Department of Energy (DOE) supported work at Lodestar Research Corporation under grant DE-SC0019270 is summarized in this final report. The research conducted under this grant explored the properties of the edge plasma in spherical torus magnetic fusion devices. Harnessing the energy that is released in fusion reactions would provide a safe and abundant source of power to meet the growing energy needs of the world population. The edge and scrape-off layer (SOL) region of fusion plasmas is the region where the hot core plasma transitions to a cooler surrounding boundary plasma. The properties of this boundary plasma determine how interactions with material surfaces will impact both the overall device performance and the lifetime of crucial components such as the walls of the device chamber and other hardware. The research carried out studied filamentary plasma instabilities and turbulent transport in the edge and SOL of the MAST U spherical torus.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

Recent MCNP® Code Developments and Improvements for Nuclear Energy Applications [Slides]

The MCNP® code is a general-purpose radiation transport code developed at LANL over the past 46+ years. This code is capable of modeling the fundamental physics of particles as they move through and interact with materials. It is used in many LANL and worldwide radiation transport applications (see next slide) for example in the Fundamental nuclear physics and data experiments at LANSCE.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Metals and Quantum Materials with Spin-orbit Interactions by Quantum Monte Carlo methods

The key goals of this project were as follows: 1) Analysis and benchmarks of electron correlation effects recovered in the fixed-node approximation that is inherent to quantum Monte Carlo (QMC) method as applied to metallic states; 2) development of new algorithms for electron spin-degrees of freedom to be treated as explicit quantum variables; 3) designing electronic structure QMC algorithm for efficient evaluation of spin-orbit effects in systems with heavy atoms; 4) adapting the algorithm to complex wave functions and developing corresponding fixed-phase approximation; 5) design and testing of algorithm for valence-only non-local spin-orbit operators; 6) analysis of fixed-node vs fixed-phase errors and their comparisons. The key accomplishments: i) We carried out a systematic study of Li systems by the fixed-node diffusion Monte Carlo method. This involved Li atom, molecule, cluster and solid calculated by the full range of QMC methods including fixed-node QMC.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗