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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 1,585 records · Page 88
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Quantitative assessment of Ni + and He + ion irradiation damage in a tungsten heavy alloy under the simulated nuclear fusion environment

A 90W-7Ni-3Fe (wt.%) tungsten heavy alloy has been sequentially Ni + and He + ion irradiated at 700 °C to simulate the high temperature irradiation environment of a fusion reactor interior. W/Ni–Fe-W dual-phase alloys have been proposed to serve as plasma facing materials and require detailed investigation of their behavior under fusion relevant conditions to assess their overall applicability. To evaluate material performance under five years of simulated fusion reactor service, microstructural characterization of the nanoscale defect distribution has been performed on both constituent phases, revealing peak swelling in the W phase of approximately 0.03%. The γ-phase (Ni–Fe-W) is found to swell approximately 0.68% under the same irradiation conditions, indicating significant cavity formation and growth. Additionally, a novel multi-projection imaging approach has been applied to determine the extent of damage segregation along the dual-phase W-to-γ interface and exposes that these interfaces act as sink sites for the accumulation of cavities. Interphase boundaries are noted to possess an 11.8% areal coverage of defects along the boundary plane, primarily on the γ-phase side of the boundary. The accumulation of cavities at these interphase boundaries is anticipated to adversely affect overall material toughness, and this work reveals a pressing need for mechanical property testing of irradiated W–Ni-Fe dual-phase alloys.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2026

Strong and recyclable bio-derived poly(ester amide) hot-melt adhesive

Bio-based adhesives offer inherent advantages over conventional petrochemical-derived systems, including renewable sourcing, reduced environmental impact and potential degradability. However, most bio-based adhesives suffer from poor adhesion strength, limited substrate compatibility and a lack of chemical recyclability. Here, in this work, we present a bio-derived multiblock poly(ester amide) adhesive that leverages microphase segregation between different segments to reconcile mechanical robustness with strong interfacial bonding. Notably, this multiblock architecture is accessed through a one-pot, selective acceptorless dehydrogenative polymerization, obviating the need for multistep synthesis. The materials exhibit excellent adhesion across a range of substrates including metals, glass and wet wood surpassing commercial benchmarks, while also demonstrating thermal stability, tunable mechanical properties and closed-loop chemical recyclability even in the presence of other commodity plastics. Furthermore, the adhesive strength of these materials could be tuned for various potential applications through control over the chemical composition of the polymer. By integrating renewable feedstocks, high-performance functionality and efficient chemical circularity within a single platform, this work provides a viable pathway toward more sustainable adhesive technologies and contributes to advancing circular materials manufacturing.

09 BIOMASS FUELS↗
DOE OSTI2023

Multigenic resistance to Xylella fastidiosa in wild grapes ( Vitis sps.) and its implications within a changing climate

Xylella fastidiosa is a bacterium that infects crops like grapevines, coffee, almonds, citrus and olives. There is little understanding of the genes that contribute to plant resistance, the genomic architecture of resistance, and the potential role of climate in shaping resistance, in part because major crops like grapevines (Vitis vinifera) are not resistant to the bacterium. Here we study a wild grapevine species, V. arizonica, that segregates for resistance. Using genome-wide association, we identify candidate resistance genes. Resistance-associated kmers are shared with a sister species of V. arizonica but not with more distant species, suggesting that resistance evolved more than once. Finally, resistance is climate dependent, because individuals from low (< 10 °C) temperature locations in the wettest quarter were typically susceptible to infection, likely reflecting a lack of pathogen pressure in colder climates. In fact, climate is as effective a predictor of resistance phenotypes as some genetic markers. We extend our climate observations to additional crops, predicting that increased pathogen pressure is more likely for grapevines and almonds than some other susceptible crops.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2024

Non-invasive ventral cervical magnetoneurography as a proxy of in vivo lipopolysaccharide-induced inflammation

Maintenance of autonomic homeostasis is continuously calibrated by sensory fibers of the vagus nerve and sympathetic chain that convey compound action potentials (CAPs) to the central nervous system. Lipopolysaccharide (LPS) intravenous challenge reliably elicits a robust inflammatory response that can resemble systemic inflammation and acute endotoxemia. Here, we administered LPS intravenously in nine healthy subjects while recording ventral cervical magnetoneurography (vcMNG)-derived CAPs at the rostral Right Nodose Ganglion (RNG) and the caudal Right Carotid Artery (RCA) with optically pumped magnetometers (OPM). We observed vcMNG RNG and RCA neural firing rates that tracked changes in TNF-α levels in the systemic circulation. Further, endotype subgroups based on high and low IL-6 responders segregate RNG CAP frequency (at 30-120 min) and based on high and low IL-10 response discriminate RCA CAP frequency (at 0-30 min). These vcMNG tools may enhance understanding and management of the neuroimmune axis that can guide personalized treatment based on an individual’s distinct endophenotype.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2021

Emergence of Lanes and Turbulent-like Motion in Active Spinner Fluid

Assemblies of self-rotating particles are gaining interest as a novel realization of active matter with unique collective behaviors such as edge currents and non-trivial dynamic states. Here, we develop a continuum model for a system of fluid-embedded spinners by coarse-graining the equations of motion of the discrete particles. We apply the model to explore mixtures of clockwise and counterclockwise rotating spinners. We find that the dynamics is sensitive to fluid inertia: in the inertialess system, after transient turbulent-like motion the spinners segregate and form steady traffic lanes. At small but finite Reynolds number instead, the turbulent-like motion persists and the system exhibits a chirality breaking transition leading to a single rotation sense state. Our results shed light on the dynamic behavior of non-equilibrium materials exemplified by active spinners.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Identifying chemically similar multiphase nanoprecipitates in compositionally complex non-equilibrium oxides via machine learning

Abstract Characterizing oxide nuclear fuels is difficult due to complex fission products, which result from time-evolving system chemistry and extreme operating environments. Here, we report a machine learning-enhanced approach that accelerates the characterization of spent nuclear fuels and improves the accuracy of identifying nanophase fission products and bubbles. We apply this approach to commercial, high-burnup, irradiated light-water reactor fuels, demonstrating relationships between fission product precipitates and gases. We also gain understanding of the fission versus decay pathways of precipitates across the radius of a fuel pellet. An algorithm is provided for quantifying the chemical segregation of the fission products with respect to the high-burnup structure, which enhances our ability to process large amounts of microscopy data, including approaching the atomistic-scale. This may provide a faster route for achieving physics-based fuel performance modeling.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Self-patterning Gd nano-fibers in Mg-Gd alloys

Manipulating the shape and distribution of strengthening units, e.g. particles, fibers, and precipitates, in a bulk metal, has been a widely applied strategy of tailoring their mechanical properties. Here, we report self-assembled patterns of Gd nano-fibers in Mg-Gd alloys for the purpose of improving their strength and deformability. 1-nm Gd nano-fibers, with a $\langle$c$\rangle$ -rod shape, are formed and hexagonally patterned in association with Gd segregations along dislocations that nucleated during hot extrusion. Such Gd-fiber patterns are able to regulate the relative activities of slips and twinning, as a result, overcome the inherent limitations in strength and ductility of Mg alloys. Finally, this nano-fiber patterning approach could be an effective method to engineer hexagonal metals.

36 MATERIALS SCIENCE↗
DOE OSTI2017

A high-density SNP genetic map consisting of a complete set of homologous groups in autohexaploid sweetpotato (Ipomoea batatas)

Sweetpotato (Ipomoea batatas) is an autohexaploid species with 90 chromosomes (2n = 6x = 90) and a basic chromosome number of 15, and is therefore regarded as one of the most challenging species for high-density genetic map construction. Here, we used single nucleotide polymorphisms (SNPs) identified by double-digest restriction site-associated DNA sequencing based on next-generation sequencing technology to construct a map for sweetpotato. We then aligned the sequence reads onto the reference genome sequence of I. trifida, a likely diploid ancestor of sweetpotato, to detect SNPs. In addition, to simplify analysis of the complex genetic mode of autohexaploidy, we used an S1 mapping population derived from self-pollination of a single parent. As a result, 28,087 double-simplex SNPs showing a Mendelian segregation ratio in the S1 progeny could be mapped onto 96 linkage groups (LGs), covering a total distance of 33,020.4 cM. Based on the positions of the SNPs on the I. trifida genome, the LGs were classified into 15 groups, each with roughly six LGs and six small extra groups. The molecular genetic techniques used in this study are applicable to high-density mapping of other polyploid plant species, including important crops.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2017

Defect interactions and the role of complexes in the CdTe solar cell absorber

While the electrical and optical properties of most crystalline materials are determined by the point defects, the association of these defects into complexes may further alter material properties, introducing new important phenomena. The properties of isolated point defects in CdTe have attracted significant research efforts, yet understanding of the complex defects in this material remains insufficient. This paper investigates the thermodynamic aspects of defect association in chlorinated copper-doped CdTe absorbers from first principles, using a supercell approach with the range-separated hybrid exchange–correlation functional. Based on the complex association energies calculated for 76 defect reactions, we propose the most favorable pair complexes formed in Cl- and Cu-doped CdTe absorbers. Most of the complexes studied in this work appear to be harmful for p-doping and may be responsible for the performance instabilities observed in CdTe devices. We also discuss a plausible passivation mechanism that mitigates TeCd recombination centers during Cl treatment. We also consider the formation of larger defect clusters and segregation of the point defects on extended defects.

14 SOLAR ENERGY↗
DOE OSTI2017

Controlling superstructural ordering in the clathrate-I Ba 8 M 16 P 30 (M = Cu, Zn) through the formation of metal–metal bonds

Order–disorder–order phase transitions in the clathrate-I Ba 8 Cu 16 P 30 were induced and controlled by aliovalent substitutions of Zn into the framework. Unaltered Ba 8 Cu 16 P 30 crystallizes in an ordered orthorhombic ( Pbcn ) clathrate-I superstructure that maintains complete segregation of metal and phosphorus atoms over 23 different crystallographic positions in the clathrate framework. The driving force for the formation of this Pbcn superstructure is the avoidance of Cu–Cu bonds. This superstructure is preserved upon aliovalent substitution of Zn for Cu in Ba 8 Cu 16– x Zn x P 30 with 0 < x < 1.6 (10% Zn/M total ), but vanishes at greater substitution concentrations. Higher Zn concentrations (up to 35% Zn/M total ) resulted in the additional substitution of Zn for P in Ba 8 M 16+ y P 30– y (M = Cu, Zn) with 0 ≤ y ≤ 1. This causes the formation of Cu–Zn bonds in the framework, leading to a collapse of the orthorhombic superstructure into the more common cubic subcell of clathrate-I ( Pm n ). In the resulting cubic phases, each clathrate framework position is jointly occupied by three different elements: Cu, Zn, and P. Detailed structural characterization of the Ba–Cu–Zn–P clathrates-I via single crystal X-ray diffraction, joint synchrotron X-ray and neutron powder diffractions, pair distribution function analysis, electron diffraction and high-resolution electron microscopy, along with elemental analysis, indicates that local ordering is present in the cubic clathrate framework, suggesting the evolution of Cu–Zn bonds. For the compounds with the highest Zn content, a disorder–order transformation is detected due to the formation of another superstructure with trigonal symmetry and Cu–Zn bonds in the clathrate-I framework. It is shown that small changes in the composition, synthesis, and crystal structure have significant impacts on the structural and transport properties of Zn-substituted Ba 8 Cu 16 P 30 .

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Modeling solvent evaporation during thin film formation in phase separating polymer mixtures

Preparation of thin films by dissolving polymers in a common solvent followed by evaporation of the solvent has become a routine processing procedure. However, modeling of thin film formation in an evaporating solvent has been challenging due to a need to simulate processes at multiple length and time scales. In this paper, we present a methodology based on the principles of linear non-equilibrium thermodynamics, which allows systematic study of various effects such as the changes in the solvent properties due to phase transformation from liquid to vapor and polymer thermodynamics resulting from such solvent transformations. The methodology allows for the derivation of evaporative flux and boundary conditions near each surface for simulations of systems close to the equilibrium. We apply it to study thin film microstructural evolution in phase segregating polymer blends dissolved in a common volatile solvent and deposited on a planar substrate. Finally, effects of the evaporation rates, interactions of the polymers with the underlying substrate and concentration dependent mobilities on the kinetics of thin film formation are studied.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Insights into operational stability and processing of halide perovskite active layers

Rapid improvement of the stability of metal halide perovskite materials is required to enable their adoption for energy production at Terawatt scale. To understand the role of the active layer stability in these devices we use operando x-ray diffraction to observe the evolution in structural stability across APbI3 alloys where A is a combination of formamidinium, Cs, and/or methylammonium. During device operation we observe spatial de-alloying and phase segregation into the alloy’s constituent phases. Using complementary first-principles calculations of halide perovskite alloys a hypothesized framework explaining the experimentally observed mixing and demixing of these systems is presented and then validated using in-situ X-ray diffraction and time of flight secondary ion mass spectrometry. Taken together these results indicate that stability is not only a function of device architecture or chemical formulation, but that the processing strategy is critically important in synthesizing the most energetically favorable state and therefore the most stable device systems. This study reconciles disparate reports within the literature and also highlights the limitations of shelf life studies to ascertain stability as well as the importance of testing devices under operational conditions.

14 SOLAR ENERGY↗
DOE OSTI2019

Ion diffusion across a disorder-to-order phase transition in a poly(ethylene oxide)- b -poly(silsesquioxane) block copolymer electrolyte

Nanostructured block copolymer electrolytes composed of organic and inorganic moieties have the potential to enable solid-state batteries. Practical uses of these materials, however, require an understanding of the microscopic and macroscopic ion transport properties across the microphase-separated systems. The self-diffusion of salt ions across a disorder-lamellar phase transition in a nanostructured poly(ethylene oxide)-b-poly(silsesquioxane) copolymer was studied using pulsed-field gradient NMR (PFG-NMR) and changes in the morphology were studied using small-angle X-ray scattering. The diffusion of the salt is isotropic when the polymer electrolyte is disordered and locally anisotropic when the polymer is microphase separated. The difference between the diffusion coefficient parallel to the lamellae, D ∥ , and the diffusion coefficient perpendicular to the lamellae, D ⊥ , measured using PFG-NMR, increases with increasing segregation strength. Finally, the anisotropy of diffusion parallels changes in the morphology measured by small-angle X-ray scattering.

42 ENGINEERING↗
DOE OSTI2019

Charging toward improved lithium-ion polymer electrolytes: exploiting synergistic experimental and computational approaches to facilitate materials design

Ion-conducting polymer electrolytes are attractive materials for all-solid-state lithium-ion batteries (LiBs) as a result of their potential to improve performance, mitigate safety concerns, and facilitate efficient device processing. Understanding how lithium-ionic transport is influenced by the macromolecular features, such as dielectric strength, solvation site connectivity, monomer segment relaxation timescales, segregation strength, and mesophase composition, is crucial for advancing ion-conducting materials. The integration of experimental and computational efforts can provide comprehensive links between chemical and structural characteristics (e.g., ion solvation, chain mobility, morphology) and macroscopic performance properties, accelerating the adoption of next-generation polymer electrolytes. Furthermore, this perspective highlights several synergistic experimental–computational approaches that have provided unique insights into local ion and polymer interactions, chain dynamics, and thermodynamics to promote the rational design of new ion-conducting polymers. Additionally, this work concludes with several suggested areas in which methodologies can be augmented, novel properties can be realized, and polymer electrolytes can be integrated to generate more robust LiB systems.

25 ENERGY STORAGE↗
DOE OSTI2018

Plasmonic circular dichroism of vesicle-like nanostructures by the template-less self-assembly of achiral Janus nanoparticles

Chiral nanostructures have been attracting extensive interest in recent years primarily because of the unique materials properties that can be exploited for diverse applications. In this study, gold Janus nanoparticles, with hexanethiolates and 3-mercapto-1,2-propanediol segregated on the two hemispheres of the metal cores (dia. 2.7 ± 0.4 nm), self-assembled into vesicle-like, hollow nanostructures in both water or organic media, and exhibited apparent plasmonic circular dichroism (PCD) absorption in the visible range. This was in contrast to individual Janus nanoparticles, bulk-exchange nanoparticles where the two ligands were homogeneously mixed on the nanoparticle surface, or nanoparticles capped with only one kind of the ligands. The PCD signals were found to become intensified with increasing coverage of the 3-mercapto-1,2-propanediol ligands on the nanoparticle surface. This was accounted for by the dipolar property of the structurally asymmetrical Janus nanoparticles, and theoretical simulations based on first principles calculations showed that when the nanoparticle dipoles self-assembled onto the surface of a hollow sphere, a vortex was formed which gave rise to the unique chiral characteristics. The resulting chiral nanoparticle vesicles could be exploited for the separation of optical enantiomers, as manifested in the selective identification and separation of D-alanine from the L-isomer

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗