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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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Unprecedented Shifts in Hydrology Are Emerging Across California's Critical Basins: An Evaluation From 0.5 to 3.5°C

With advances in climate models and downscaling techniques, stakeholders anticipate high-resolution analysis to inform regional to local changes in water management. Here, we produce hydrologic projections from an ensemble of Earth System Models (ESMs) that were selected and downscaled to support California's 5th Climate Assessment. An ensemble of 19 ESMs was downscaled to a 3-km resolution across California using a statistical-dynamical downscaling approach and subsequently run through two calibrated hydrology models. Although California has been extensively studied in the context of climate change, we provide the first evaluation of the warming thresholds at which hydroclimate metrics demonstrate statistically significant shifts. We show that present-day to near-term warming levels in Klamath and Northern Sierra Nevada basins, which serve as a critical source of water for California, show statistically significant decreases in snowfall and peak snowpack and associated decreases in summer snowmelt and runoff. More generally, shifts in these hydroclimate metrics occur for intermediate elevation basins ranging from 1,315 to 1,455 m (4,314.3–4,773.6 ft), while the warming level of emergence is delayed for lower and higher elevation basins. We also find that several basins already demonstrate significant increases in 5- to 100-year runoff intensities, primarily due to the increasing influence of precipitation falling as rain. Hydroclimate metrics with trends that demonstrate near-term warming levels of emergence are reflected in reanalysis-based observations, suggesting California is entering a fundamentally different hydroclimate regime. While this will likely stress California's water management, the research provided can support when to implement adaptation efforts.

Bass, B. [Univ. of California, Los Angeles, CA (Un↗
DOE OSTI2025

New proton emitter 188 At implies an interaction unprecedented in heavy nuclei

We report the discovery of a new atomic nucleus 188 At, which is the heaviest proton-emitting isotope known to date. The new activity was observed through the 107 Ag( 84 Sr, 3n) 188 At fusion-evaporation reaction using the focal-plane spectrometer of the gas-filled recoil separator in the Accelerator Laboratory of the University of Jyväskylä, Finland. To fully interpret the experimental data, we have expanded the non-adiabatic quasiparticle model to treat nuclei in the beyond-lead region. The description reproduced the measured decay rate and pointed towards emission from an extremely prolate-deformed state with a dominant s 1/2 proton component in the wave function. The Thomas-Ehrman shift can be enhanced in low angular momentum states, but such effects have not been observed in heavy nuclei. The single-proton separation energy of 188 At deviates from that extrapolated from the systematics, which can be interpreted as the first evidence of this effect in heavy nuclei.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2026

Linear complexions enable unprecedented ductility retention in neutron irradiated ferritic steel

Herein, the operando formation of Si-enriched linear complexions during neutron irradiation enables Grade 91 ferritic steel to overcome the strength–ductility tradeoff, one of the most critical life-limiting challenges facing nuclear structural alloys. Linear complexions are a distinct yet confined chemical and structural state at a dislocation, which are rarely reported in engineering alloys. Ferritic steels are amongst the most ubiquitous engineering alloys for current and future nuclear components, but they are susceptible to irradiation hardening and embrittlement. Here, exceptional ductility retention exceeding 90% of pre-irradiation levels is obtained in Grade 91 synthesized using powder metallurgy with hot isostatic pressing (PM-HIP). Powder processing artifacts promote a high density of screw dislocation arrays, on which β-FeSi 2 linear complexions form due to Si segregation during irradiation. Screw dislocation dipoles undergo pinning and unpinning on linear complexions, resulting in extended yielding and significant ductility retention post-irradiation. These findings represent a significant advancement toward design of alloys and manufacturing processes that can autonomously self-regulate their microstructural resilience in-operando during irradiation, enabling exceptional ductility rather than embrittlement.

Chatterjee, Arya [University of Illinois, Urbana, ↗
DOE OSTI2021

An unprecedented quinoid–donor–acceptor strategy to boost the carrier mobilities of semiconducting polymers for organic field-effect transistors

Quinoidal–aromatic conjugated polymers hold great application potential in organic field-effect transistors (OFETs). However, the development of high mobility quinoidal–aromatic conjugated polymers still lags behind the more popular donor–acceptor (D–A) conjugated polymers, mainly owing to the lack of a rational design strategy and efficient building block. Herein, a novel quinoid–donor–acceptor (Q–D–A) strategy is demonstrated to modulate the energy-level and boost the charge carrier transport mobility of conjugated polymers as opposed to the D–A system. On the basis of this strategy, a quinoidal–aromatic conjugated polymer, namely PAQM-BT, is designed and synthesized. With the combined use of quinoid, donor and acceptor units in the backbone, the resulting Q–D–A polymer PAQM-BT displays the narrowest bandgap with the deepest-lying lowest unoccupied molecular orbital (LUMO) energy level, highest backbone coplanarity, enhanced thin-film crystallinity and smallest effective hole mass ($m^*_h$) in comparison with the corresponding D–A polymer PT3B1 and quinoid–donor (Q–D) polymer PAQM-3T. Benefitting from the more effective intra- and inter-chain charge transport, as corroborated by experiment and theoretical calculations, OFET devices based on PAQM-BT exhibit a highly boosted hole mobility of up to 5.10 cm 2 V -1 s -1 , which is one and four orders of magnitude higher than that of PAQM-3T and PT3B1, respectively, and is among the highest for quinoidal–aromatic conjugated polymers. Finally, the potent Q–D–A strategy not only allows the energy level to be modulated but also leads to effective charge carrier transport, opening up possibilities to the development of high mobility quinoidal–aromatic conjugated polymers based on a variety of quinoids, donors, and acceptors.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Unprecedented Beaufort Sea ice loss in late summer 2021 and its relationship to an extended period of unusually stormy weather

Previous case studies have linked cyclone-induced atmospheric forcing and/or upper-ocean processes to notable Arctic sea ice loss events in the summers of 2012 and 2016. This study examines a more recent and noteworthy case in late summer 2021 in which substantial sea ice loss followed a period of surface meteorological extremes in the Beaufort Sea region of the Arctic. We focus on the period from mid-August to mid-September 2021 that coincided with the Office of Naval Research THINICE Pilot Field Campaign and investigate stormy and windy conditions with respect to air-sea processes impacting sea ice conditions. We find that during the stormy first half of the campaign, cyclone-induced energy fluxes into the marginal ice zone and surrounding waters preconditioned the ice pack for more rapid melt later in the campaign. The second half of the campaign, in contrast, was marked by non-cyclone wind events that enhanced turbulent (namely sensible) heat fluxes into the ice and upper ocean that increased melt. Moreover, this latter period had enhanced advection of the Beaufort Sea ice pack into above-freezing waters, increasing bottom melt to >1 cm d −1 over the remainder of the campaign. While findings are shown to vary by surface type and at relatively small (i.e. ice-floe) scales, insights are offered on the roles of late summer coupled processes on rapid ice loss events in today’s Arctic environment.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2025

Observation of Unprecedented Fractional Magnetization Plateaus in a New Shastry-Sutherland Ising Compound

Geometrically frustrated magnetic systems, such as those based on the Shastry-Sutherland lattice (SSL), offer a rich playground for exploring unconventional magnetic states. The delicate balance between competing interactions in these systems leads to the emergence of novel phases. We present the characterization of Er 2 ⁢Be 2⁢ GeO 7 , an SSL compound with Er 3+ ions forming orthogonal dimers separated by nonmagnetic layers whose structure is invariant under the 𝑃⁢$\bar{4}21$⁢𝑚 space group. Neutron scattering reveals an antiferromagnetic dimer structure at zero field, typical of Ising spins on that lattice and consistent with the anisotropic magnetization observed. However, magnetization measurements exhibit fractional plateaus at 1/4 and 1/2 of saturation, in contrast to the expected 1/3 plateau of the SSL Ising model. By comparing the energy of candidate states with ground-state lower bounds we show that this behavior requires spatially anisotropic interactions, leading to an anisotropic Shastry-Sutherland Ising model symmetric under the 𝐶⁢𝑚⁢𝑚⁢2 space group. This anisotropy is consistent with the small orthorhombic distortion observed with single-crystal neutron diffraction. The other properties, including thermodynamics, which have been investigated theoretically using tensor networks, point to small residual interactions, potentially due to further couplings and quantum fluctuations. This study highlights Er 2 ⁢Be 2 ⁢GeO 7 as a promising platform for investigating exotic magnetic phenomena.

Yadav, Lalit [Duke University, Durham, NC (United ↗
DOE OSTI2025

Electric Grid Reliability in an Era of Unprecedented Uncertainty: A Review of Advances in Electric Sector Resource Adequacy Assessment and Planning

Recent changes to the principal causes of energy shortage events on the electric grid have necessitated are thinking of paradigms for resource adequacy (RA) assessment and the related topic of procurement of a reliable portfolio. Prior studies have laid out elements of a modern paradigm for these planning activities, but there does not exist a comprehensive overview of the topic spanning academic and gray literature, and the relationship of these suggested paradigms to methods used in industry has also not been surveyed. In this paper we review recent literature establishing best practices for RA assessment and reliable portfolio procurement, and survey current practices used in industry in relation to these best practices. We establish seven key best practices for RA assessment, cover a modern methodology for capacity accreditation, and find that industry practices are not far behind the identified best practices, though some key gaps remain. We also present a suggested agenda for both academic research on the topic and opportunities for advancement in the industry.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2024

Ultra-compact and efficient heat exchanger for solar desalination with unprecedented scaling resistance

The objective is to design, prototype, and test a heat exchanger technology with an efficiency improvement of more than 150% compared to state-of-the-art heat exchanger technology (UA/volume), with significantly improved fouling/scaling resistance at elevated temperatures (>120°C) when compared to existing technology where scaling is a major performance-limiting issue, as well as at lower operating-temperatures (~63-110°C). We now report our overall progress on the project. An ultra-compact, efficient heat exchanger geometry has been developed that can maximize surface-area-to-volume ratio so that proposed target (UA/volume). Advanced manufacturing techniques, such additive manufacturing, have made it possible to create complex structures cost effectively. In addition to traditional manufacturing methods, additive manufacturing has been successfully used for the development of high-performance geometries. These methods allow the ability to create custom surface textures, which are deployed to dramatically control wettability and create energy-gradient surfaces. These techniques allow fouling/scaling nucleation to be spatially controlled, such that as the fouling layer grows it will be broken and removed by flow forces.

42 ENGINEERING↗
DOE OSTI2024

WarpX: Delivering Unprecedented Particle-in-Cell Simulation Capability

Since 1939, more than 30 percent of all Nobel prizes in physics and four of the past 14 prizes in chemistry have been awarded for work with particle accelerators. These tools are now used to treat cancer and produce medical supplies, support research in applied fields such as pharmaceuticals, create microcircuits, and sterilize food—and the applications list continues to grow. However, the size of the facilities needed to house these machines—which are often dozens of kilometers long—has limited their future potential. Thus, researchers are motivated to create novel particle accelerator designs that provide new imaging capability but have a much smaller footprint. The Exascale Computing Project’s WarpX application captures the full complexity of the acceleration processes within plasma-based design, supporting the rapid and cost-efficient development of tens of thousands of new particle accelerators for various applications from improving human health to nuclear fusion reactors.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2024

Achieving Unprecedented CO 2 Utilization InCO 2 Concrete™: System Design, Product Development and Process Demonstration

Anthropogenic sources of carbon dioxide are generated from a number of sources, but the key among these are ordinary Portland cement (OPC) production and combustion of fossil fuels. Cement production is the largest global CO 2 source from the mineral decomposition of carbonates. This is due to the clinkering process whereby limestone (mainly consisting of CaCO 3 ) is decomposed into CaO and CO 2 , and combined with silica rich clays at high temperatures to form clinkers (i.e. the four key minerals that comprise cement). The high temperature range of 1400 – 1550°C required for this process accounts for up to 60% of the generated CO 2 from cement production. Combination of the limestone decomposition and thermal requirements of the clinkering process causes cement production to contribute 8-9% of annual global CO 2 emissions. Combustion of fossil fuels (coal, oil and gas) was shown to contribute a much larger portion of global CO 2 emissions. As of 2018, combustion of fossil fuels accounted for 65% of global CO 2 , where 41% was derived from stationary sources for electricity and heat generation and the other 24% was related to transport. To reduce these contributions, key steps forward in CO 2 utilization technologies are required. Therefore, a CO 2 mineralization technology (CO 2 mineralization concrete) to reduce the OPC content in concrete, while utilizing flue gas emissions from fossil fuel combustion has been developed to address both areas simultaneously. This Reversa™ technology utilizes low-carbon cementation agents produced by in situ CO 2 mineralization (“mineral carbonation reactions”) to offer a promising alternative to OPC. CO 2 mineralization relies upon the reaction of dissolved CO 2 with inorganic alkaline reactants to precipitate mineral carbonates (e.g., CaCO 3 ), which bind proximate particles and achieve cementation. Herein, a concrete green body, which is composed of a mixture of binder, water, and mineral aggregates, is exposed to CO 2 borne in industrial flue gas streams. This manner of CO 2 mineralization allows the production of construction components that feature equivalent engineering attributes as their OPC-based counterparts while featuring a much smaller embodied carbon intensity (eCI). The purpose of this project is to demonstrate the feasibility of the Reversa process evolving from a TRL-3 technology at the bench-scale up to TRL-6 technology at the pilot-scale. The reliability of the Reversa technology was tested to prove the effective production of three standard industrial concrete products selected during the course of the project. The results detailed herein will demonstrate the evolution of this technology to the industrial scale. The culmination of this work resulted in 9 production runs completed at the National Carbon Capture Center (NCCC), Wilsonville, AL, using natural gas (NG) flue gas as the CO 2 source. Over the course of the production runs at NCCC, the CO 2 utilization as a function of time, 24-h CO 2 uptake, electricity usage, and 28-d net area compressive strength recorded for each run. Collection of this data will be used to determine the success of the demonstration goals: (1) achieving in excess of 0.2gCO 2 /g reactant , (2) achieving greater than 50% reduction in global warming potential compared to standard produced units, and (3) ensuring compliance of carbonated concrete with industry standard specifications.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Al-Ce Alloy-Based Compact Heat Exchanger for Refrigerant Charge Reduction and Unprecedented Durability (CRADA NFE-21-08888 Final Report)

Oak Ridge National Laboratory and Eck Industries produced and characterized durable and corrosion resistant Al-Ce-Mg alloy-based heat exchanger. Eck Industries successfully casted Al-Ce-Mg heat exchanger. ORNL characterized reaction bonding between Al-2Ce-6Mg alloy and stainless-steel tube in a heat exchanger header. Metallurgical bonds were achieved between stainless steel tubes and Al-Ce-Mg alloy cast headers. ORNL performed corrosion testing on Al-Ce-Mg alloy/stainless steel tube reactive bond interface. In most cases no significant changes to the reactive bond morphology or compositional distribution were observed in the samples after exposure to acid for 267h acid.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Al-Ce Alloy-Based Compact Heat Exchanger for Refrigerant Charge Reduction and Unprecedented Durability

• Oak Ridge National Laboratory and Eck Industries produced and characterized durable and corrosion resistant Al-Ce-Mg alloy-based heat exchanger. • Eck Industries successfully casted Al-Ce-Mg heat exchanger. • ORNL characterized reaction bonding between Al-2Ce-6Mg alloy and stainless-steel tube in a heat exchanger header. • Metallurgical bonds were achieved between stainless steel tubes and Al-Ce-Mg alloy cast headers. • ORNL performed corrosion testing on Al-Ce-Mg alloy/stainless steel tube reactive bond interface. • In most cases no significant changes to the reactive bond morphology or compositional distribution were observed in the samples after exposure to acid for 267h acid.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Generation and Study of Am(IV) by Temperature-Controlled Electron Pulse Radiolysis

Used nuclear fuel (UNF) separation techniques that strive to separate radiotoxic americium (Am) from trivalent lanthanide fission products through oxidation state control have increased research efforts surrounding Am(V) and Am(VI). However, equivalent knowledge of the tetravalent state, Am(IV), has remained elusive, particularly in conditions more representative of UNF reprocessing, i.e., in concentrated nitric acid (HNO3). With this in mind, we have used electron pulse radiolysis to study the radiation-induced redox reaction of Am(III) with the oxidizing nitrate radical (NO3?) in 6 M HNO3: Am(III) + NO3? ? Am(IV) + NO3? . These experiments enabled us to observe the growth and decay of Am(IV) in a concentrated acidic solution for the first time. The transient Am(IV) species was found to have a lifetime of ~16 µs?sufficiently long-lived to play a critical mechanistic role in UNF reprocessing systems. Additionally, we performed the first-ever temperature-dependent kinetics study of an actinide element, elucidating unprecedented Arrhenius and Eyring activation parameters for the reaction of Am(III) with NO3?. This new knowledge provides much-needed molecular-level insights into the radiation-induced behavior of Am.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗