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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 271 records · Page 15
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Unprecedented electrical performance of friction-extruded copper-graphene composites

Copper-graphene composites show remarkable electrical performance surpassing traditional copper conductors albeit at a micron scale; there are several challenges in demonstrating similar performance at the bulk scale. In this study, we used shear extrusion to synthesize macro-scale copper-graphene composites with a simultaneously lower temperature coefficient of resistance (TCR) and improved electrical conductivity over copper-only samples. We showed that the addition of 18 ppm of graphene decreased the TCR of C11000 alloy by nearly 11%. A suite of characterization tools involving scanning and transmission electron microscopy along with atom probe tomography were used to characterize the grain size, crystallographic orientation, structure, and composition of copper grains and graphene additives in the feedstock and processed samples. We posit that the shear extrusion process may have transformed some of the feedstock graphene additives into higher defect-density agglomerates while retaining the structure of others as mono-to-trilete flakes with lower defect density. The combination of these additives with heterogeneous structures may have been responsible for the simultaneous decrease in TCR and enhanced electrical conductivity of the copper-graphene ShAPE composites.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Utah FORGE Friction-Permeability-Seismicity Laboratory Experiments with Non-Linear Acoustics

Laboratory experimental data on saw-cut interface of Westerly Granite and Utah Forge granitoid rocks. Experiments include velocity-stepping and fluid pressure stepping experiments. Mechanical data from 3 ISCO pumps connected to a Temco pressure vessel measure axial, confining and fault: fluid pressure (kPa), fluid flow rate (mL/min) and volume remaining in pump (mL). Non-linear acoustic data acquired via Verasonics systems connected to PZTs inside the pressure vessel give the timeshift, amplitude and RMS amplitude of the passing P-wave.

15 GEOTHERMAL ENERGY↗
DOE OSTI2023

Flow friction in a wide rectangular duct with a beveled inlet: Informal Notes of Fundamental Fluid Physics Studies

Fundamental streamwise pressure distributions were measured at Idaho State University to address a primary objective of obtaining insight into the apparent evolution of air flow regimes at moderate Reynolds numbers in thin, wide rectangular ducts with converging inlets. Ducts of 3.030 and 4.077 mm spacings s (called three and four mm), having non-dimensional lengths of (L/s) ≈ 500.8 and 372.2 and widths (W/s) ≈ 114.6 and 83.2, respectively, were compared. Flow rates ranged from Reynolds numbers based on hydraulic diameter (Re Dh ) of about 980 to 10,000 and corresponding non-dimensional downstream pressure gradient parameters (-K p ) covered the range 0.038 to 0.0061, respectively.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2023

NanoMechanics: Elasticity and Friction in Nano‐Objects

A large scientific and technological effort is underway to investigate the properties of two‐dimensional (2D) materials to become building blocks in integrated nano‐electronic and photonic circuits, composites, coatings, energy harvesting nano‐ systems, nano‐sensors, and nano‐electro‐mechanical systems (NEMS).While several experiments and calculations have revealed exciting novel phenomena in these nanostructures, many scientific and technological questions remain open. In particular, understanding and controlling the structure and mechanical properties of 2D materials at the interface with a solid surface is of key importance to enable the aforementioned nanotechnologies, as well as to fulfill the potential of strain engineering to tailor their properties. The vision of this DoE research program was to investigate novel mechanical properties and phenomena in 1D and 2D materials with the overarching goal of defining a new basic understanding of mechanical behavior in nano and quantum systems. The group of the PI has developed in the last years several studies on the mechanical properties of Carbon nanotubes and oxide nanobelts, more recently the PI has focused her attention on the properties of two‐dimensional materials, such as graphene and MoS 2 , which are a few‐atomic‐layer thick films and hold a great potential for technological and energy applications. The most studied 2D material is graphene, existing as a single layer of graphite or a few‐layer thick epitaxial graphene film. Graphene possesses a large in‐plane Young’s modulus as well as high intrinsic carrier mobility, and high in‐plane thermal conductivity. Besides graphene, also 2D films of graphene oxide (GO), hexagonal Boron Nitride (h‐BN), and transition metal dichalcogenides such as MoS 2 exhibit unique and excellent properties and hold great promise for nanotechnology applications. This research program was aimed at developing a new basic understanding of the mechanical properties of 1D and 2D materials at the interface with solid substrates, with a focus on the role of defects, materials structure, and substrate interaction. Ultimately, we aimed at developing the basic knowledge and experimental tools for manipulating 1D and 2D materials’ structure, stacking, substrate interaction, defects, and number of layers to realize an entirely new class of ultra‐hard, ultra‐thin, and ultra‐light active materials with ad‐ hoc mechanical properties for a variety of applications.

2D Materials↗
DOE OSTI2025

MCPC Friction Stir Welding (FSW) Process Data

Processing parameters and machine log data for the MCPC LDRD Agile investment is collected material samples processed. This dataset captures the selected processing parameters, machine logs captured during material processing, and descriptions of how characterization samples were extracted from processed plates of material. The collect characterization data is captured in other datasets.

316 Stainless Steel↗