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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 289 records · Page 16
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

Flow quality studies of the NASA Lewis Research Center 8- by 6-foot supersonic/9- by 15-foot Low Speed Wind Tunnel

A series of studies were conducted to determine the existing flow quality in the NASA Lewis 8 by 6 Foot Supersonic/9 by 15 Foot Low Speed Wind Tunnel. The information gathered from these studies was used to determine the types and designs of flow manipulators which can be installed to improve overall tunnel flow quality and efficiency. Such manipulators include honeycomb flow straighteners, turbulence reduction screens, corner turning vanes, and acoustic treatments. The types of measurements, instrumentation, and results obtained from experiments conducted at several locations throughout the tunnel loop are described.

Arrington, E. A.↗
DOE OSTI2025

Evaluating grid stress and reliability in future electricity grids across a range of demand, generation mix, and weather trends

The reliability of power grids in the future will depend on how system planners account for the integration of new technologies, extreme weather events, and uncertainties in demand growth from increased electrification and data centers. This study introduces an open-source, multisectoral, multiscale modeling framework that projects grid stress and reliability trends between 2020 and 2055 in the Western Interconnection of the United States. The framework integrates global to national energy-water-land dynamics with power plant siting and hourly grid operations modeling. We analyze future wholesale electricity price shocks and unserved energy events across eight scenarios spanning a range of population growth and economic change, generation mixes, and weather conditions. Our results show future grids with high percentage of non-renewable generation and strong economic growth are characterized by higher reliability and lower wholesale electricity prices than lower growth scenarios because of larger reliance on dispatchable generators and lower fossil fuel extraction costs. Scenarios with high percentage of renewable resources have lower median but more volatile wholesale electricity prices as well as more frequent and severe unserved energy events compared to scenarios relying more on dispatchable generators. These events occur because higher proportion of solar and wind energy causes net demand curves to deepen during midday (duck curves get progressively severe), exacerbating the challenge of meeting demand during summer evening peaks. This study suggests that robust and co-optimized transmission and energy storage planning could help maintain low wholesale electricity prices and high reliability levels in future electricity grids across uncertainties in generation mixes.

Electric grid reliability↗
DOE OSTI2023

Nanoscale Magnetic Domains in Polycrystalline Mn 3 Sn Films Imaged by a Scanning Single-Spin Magnetometer

Noncollinear antiferromagnets with novel magnetic orders, vanishingly small net magnetization, and exotic spin related properties hold enormous promise for developing next-generation, transformative spintronic applications. A major ongoing research focus of this community is to explore, control, and harness unconventional magnetic phases of this emergent material system to deliver state-of-the-art functionalities for modern microelectronics. Here we report direct imaging of magnetic domains of polycrystalline Mn 3 Sn films, a prototypical noncollinear antiferromagnet, using nitrogen-vacancy-based single-spin scanning microscopy. Nanoscale evolution of local stray field patterns of Mn 3 Sn samples are systematically investigated in response to external driving forces, revealing the characteristic “heterogeneous” magnetic switching behaviors in polycrystalline textured Mn 3 Sn films. Furthermore, our results contribute to a comprehensive understanding of inhomogeneous magnetic orders of noncollinear antiferromagnets, highlighting the potential of nitrogen-vacancy centers to study microscopic spin properties of a broad range of emergent condensed matter systems.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2022

UV-induced dissociation of CH 2 BrI probed by intense femtosecond XUV pulses

The ultraviolet (UV)-induced dissociation and photofragmentation of gas-phase CH 2 BrI molecules induced by intense femtosecond extreme ultraviolet (XUV) pulses at three different photon energies are studied by multi-mass ion imaging. Using a UV-pump–XUV-probe scheme, charge transfer between highly charged iodine ions and neutral CH 2 Br radicals produced by C–I bond cleavage is investigated. In earlier charge-transfer studies, the center of mass of the molecules was located along the axis of the bond cleaved by the pump pulse. In the present case of CH 2 BrI, this is not the case, thus inducing a rotation of the fragment. We discuss the influence of the rotation on the charge transfer process using a classical over-the-barrier model. Our modeling suggests that, despite the fact that the dissociation is slower due to the rotational excitation, the critical interatomic distance for charge transfer is reached faster. Furthermore, we suggest that charge transfer during molecular fragmentation may be modulated in a complex way.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2025

Magnetic Ni-N-Ni Centers in N-substituted NiO

Here, to explore how anion substitution modifies the existing magnetism in strongly correlated oxides, we investigate local electronic states and magnetic ordering in nickel oxide (NiO) induced by substituting oxygen (O) with nitrogen (N). Each N introduces an additional N 2p hole and modifies the magnetic moment of a neighboring nickel (Ni) cation site, as the exchange interaction between this hole and the Ni $e_{g}$ electrons exceeds the Ni-O-Ni superexchange interaction. This leads to the formation of Ni-N-Ni centers consisting of five spins, without perturbing the antiferromagnetic NiO lattice. These centers are studied using density functional theory and confirmed through high-resolution spectroscopy on N-substituted NiO thin films grown by molecular beam epitaxy. This type of magnetic design may enable future advances in quantum technologies based on strongly correlated materials, such as quantum sensors and spin-based qubits.

Godin, Simon [Univ. of British Columbia, Vancouver↗
DOE OSTI2024

Optimization of Structurally Enhanced Solder Transient Liquid Phase Bonding

High temperature packaging technologies are a necessity for high temperature capable devices. SAC305 solder has an operational limit of 174°C imposed by creep effects which aligns well with current junction temperature limits of 175°C. Wide band gap semiconductor materials have the potential to reach junction temperatures of up to 800°C that are not currently attainable with significant reliability. Capitalizing on this potential will requires substrates and attachments that can operate well beyond the current 175°C standard. Silver sintering pastes have received widespread interest as a high temperature attachment alternative. However, the process requires high pressure bonding in an inert environment to achieve acceptable bond quality. Transient liquid phase (TLP) sintering is capable of good bond quality without pressure requirements but suffers from low thermal conductivity and only slightly reduced cost compared to silver sintering. SAC305 solder contains the same constituent materials for TLP as available copper-tin TLP sintering paste. By introducing engineered surface structures into the bond, intermetallic formation can be accelerated producing a bond similar to TLP sintering but in an ambient environment and for reduced cost. While this process has been demonstrated, it has not yet been optimized. Currently bonds are formed using a 75 μm stencil on substrate surface structures 24 μm tall, covering 19% of the bonding area. The process takes about 4 hours not including the formation of surface structures. Here, this study will center on the effects of stencil thickness and coating methods. Samples will be analyzed by scanning acoustic microscopy, die shear testing and cross sectional scanning acoustic microscopy.

42 ENGINEERING↗
DOE OSTI2024

Data Center Immersion Cooling: A Case Study and Summary of High-Performance Computing Cooling Technologies

The future of High Performance Computing (HPC) is carved out for all high-performance facilities. As computer processing increases exponentially, especially with the demand for AI training, more speed will equate to more computing density and ultimately more power draw and resource demand. Sandia National Laboratories has not seen or known of anything that would lead us to think this might change in the next 5 to 10 years.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2025

New Mobility Technology Assessment - Benefits, Risks, and Safety

The age of vehicle automation is upon us. The fundamental perception and control technology is maturing as we speak (and write) with robo-taxis proliferating in select US cities. The news cycle is no longer filled with technological skepticism, but rather societal commentary on our collective response and use of the technology. This maturing of the technology is also accompanied by a renaissance in new types of urban movement technology to more effectively link people with goods, services, and employment, particularly in dense development areas where vehicle congestion (even automated vehicles) prevents high quality mobility. The National Renewable Energy Laboratory, through the DOE Clean Energy to Communities (C2C) program has worked with two jurisdictions to assess the benefits, risks, and safety concerns for a new product offering based on suspended cable technology which is fully automated and proposes an aerial network of self-propelled gondolas. The recognized need, independent of the technology, is to fairly assess the benefits of the proposed transportation system, assess its technical maturity, as well as risks and safety concerns. Using this new technology as an example, a technology represented by Swyft Cities, NREL developed a succession of mini-studies that characterized the technical maturity level, assessed the proposed benefits for Greenville, SC, examined the risks involved in moving forward with an emerging mobility technology, and determined the governing safety protocols and standards that are applicable to the space. These mini-case studies, though centered on Swyft Cities aerial automated gondola technology, are highly transferable to any type of new mobility technology and lays out a repeatable process for assessing new technology within an city or community context.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2022

Spectroscopic Studies of Mononuclear Molybdenum Enzyme Centers

A concise review is provided of the contributions that various spectroscopic methods have made to our understanding of the physical and electronic structures of mononuclear molybdenum enzymes. Contributions to our understanding of the structure and function of each of the major families of these enzymes is considered, providing a perspective on how spectroscopy has impacted the field.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1972

Geographic applications of ERTS-A imagery to rural landscape change

There are no author-identified significant results in this report. The study area, centered on Knoxville, Tennessee, encompasses nearly 20,000 square miles. The Knoxville Test Site, an 11 x 21 mile area over the city of Knoxville and the western portion of Knox County, has been chosen for the analysis of landscape change detection associated with urban growth. The second area, the Cumberland Plateau Test Site, exhibits landscape change through forest alterations and landform disturbances associated with strip mining in the area and was so chosen for its sharp contrasts in physical and human phenomena as well as its change dynamics. Accomplishments since reception of ERTS-1 imagery include: (1) basic cataloging and classifying of the data into a filling system; (2) a densitometer analysis; (3) first look analysis; and (4) preparation of results from the project. Examples of all four bands of the MSS have been received and analyses reveal distinctive positive and negative reactions. Band 5 has been found to be best for landscape analysis of contrasts between urban and rural landscapes, and band 7 for topographic features and water surfaces. Preliminary results are summarized.

Rehder, J. B.↗
NASA NTRS1974

Preliminary analysis of an extensive one year survey of trace elements and compounds in the suspended particulate matter in Cleveland, Ohio

Beginning in 1971 a cooperative program has been carried on by the City of Cleveland Division of Air Pollution Control and NASA Lewis Research Center to study the trace element and compound concentrations in the ambient suspended particulate matter in Cleveland Ohio as a function of source, monitoring location and meteorological conditions. The major objectives were to determine the ambient concentration levels at representative urban sites and to develop a technique using trace element and compound data in conjunction with meteorological conditions to identify specific pollution sources which could be developed into a practical system that could be readily utilized by an enforcement agency.

King, R. B.↗
NASA NTRS1975

Infrared, X-ray, and XUV astrophysics

An observational program covering wavelengths from the near infrared to 1 millimeter is reviewed. The program of millimeter observations largely consisted of analyzing previous observations since the summer humidity was too high for new observations. Maps of millimeter emission from W3, Sgr B2, W49 and M42 were made. Five extragalactic sources were detected and are discussed. Energy distributions of several of the discrete sources at the Galactic Center were studied. A 5-year visual/infrared program on Markarian galaxies is discussed which showed the presence of both thermal and nonthermal infrared radiation sources and established correlations between the infrared sources and the emission line regions. The Nova Cygnus 1975, caught during its rise as well as subsequent dimming, is also discussed. Several other continuing programs are described, including studies of dark clouds and CO maser sources.

Source record↗