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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 1,243 records · Page 69
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Second spectrum of Chromium (Cr II) Part I: New energy level reanalysis

Using a linked-parametric technique of level-fitting calculations in a multiconfiguration basis, a parametric fine structure (fs) analysis for both even and odd parities of Cr II was achieved. For the first time the fs parameter, magnetic Landé g-factor and the percentage of leading eigenvector values for more than one thousand levels are determined and given for these two sets. This study has led us to confirm in the whole the well founded basis of NIST team works but inevitably also to exchange assignments of some levels classified in earlier lists of energy levels and to shift positions of some quartets like {sup 4}F{sub J} for instance. Furthermore we take this opportunity to add our predicted doublet, quartet and sextet locations for missing experimental levels up to 124,000 cm{sup −1}.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2018

Impact of community engagement on public acceptance towards waste-to-energy incineration projects: Empirical evidence from China

Highlights: • How community engagement affects public acceptance towards WTE projects is studied. • Public acceptance is affected by demographic variables. • Public trust positively affects public acceptance both directly and indirectly. • Community engagement can effectively enhance public trust in WTE authorities. - Abstract: As one of the most popular methods for the treatment of municipal solid waste (MSW), waste-to-energy (WTE) incineration offers effective solutions to deal with the MSW surge and globe energy issues. Nevertheless, the construction of WTE facilities faces considerable and strong opposition from local communities due to the perceived potential risks. The present study aims to understand whether, and how, community engagement improves local residents’ public acceptance towards waste-to-energy (WTE) incineration facilities using a questionnaire survey conducted with nearby residents of two selected WTE incineration plants located in Zhejiang province, China. The results of data analysis using Structural Equation Modeling (SEM) reveal that firstly, a lower level of public acceptance exists among local residents of over the age of 35, of lower education levels, living within 3 km from the WTE Plant and from WTE incineration Plants which are under construction. Secondly, the public trust of local government and other authorities was positively associated with the public acceptance of the WTE incineration project, both directly and indirectly based on perceived risk. Thirdly, community engagement can effectively enhance public trust in local government and other authorities related to the WTE incineration project. The findings contribute to the literature on MSW treatment policy-making and potentially hazardous facility siting, by exploring the determinants of public acceptance towards WTE incineration projects.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2025

La 3 CuTe 5 : A Narrow-Gap Semiconductor with Indirect Gap and Dual-Regime Thermally Activated Transport

Metal-chalcogenide systems remain a long-standing research topic because of their structural diversity and potential to host emergent phenomena. Here, we report a new compound, La 3 CuTe 5 , synthesized from the halide-flux method. Single-crystal X-ray diffraction studies indicate the structure to be unique among reported ones. Here, the compound crystallizes in a novel structure type adopting the orthorhombic space group Pnma and a unit cell of a = 24.3947(14) Å, b = 4.4232(2) Å, and c = 10.2142(5) Å. The tetrahedral [CuTe 4 ] building blocks form chains along [010] by corner sharing and link [LaTe 7 ] and [LaTe 8 ] polyhedra via edge sharing, resulting in a three-dimensional bulk structure. Thermal analysis results indicate that the material remains stable with a temperature up to 950 °C and decomposable at 1400 °C. First-principles calculations reveal an indirect electronic band gap and flat valence bands dominated by Te p and Cu d states. Optical absorption measurements yield a band gap of ∼0.65 eV, consistent with semiconducting behavior observed in transport measurements. Fittings to the temperature-dependent resistivity reveal two thermally activated regimes associated with Arrhenius-type conduction and three-dimensional variable range hopping, respectively.

Chalcogenides↗
DOE OSTI2020

Probing the Local Site Disorder and Distortion in Pyrochlore High-Entropy Oxides

High-entropy oxides (HEOs) have attracted great interest in diverse fields because of their inherent opportunities to tailor and combine materials functionalities. The control of local order/disorder in the class is by extension a grand challenge toward realizing their vast potential. In this paper, we report the first examples of pyrochlore HEOs with five M-site cations, for Nd 2 M 2 O 7 , in which the local structure has been investigated by neutron diffraction and pair distribution function (PDF) analysis. The average structure of the pyrochlores is found to be orthorhombic Imma, in agreement with radius-ratio rules governing the structural archetype. The computed PDFs from density functional theory relaxed special quasirandom structure models are compared with real space PDFs in this work to evaluate M-site order/disorder. Reverse Monte Carlo combined with ab initio molecular dynamics and Metropolis Monte Carlo simulations demonstrates that Nd 2 (Ta 0.2 Sc 0.2 Sn 0.2 Hf 0.2 Zr 0.2 ) 2 O 7 is synthesized with its M-site local to nanoscale order highly randomized/disordered, while Nd 2 (Ti 0.2 Nb 0.2 Sn 0.2 Hf 0.2 Zr 0.2 ) 2 O 7+x exhibits a strong distortion of the TiO 6 octahedron and small degree of Ti chemical short-range order (SRO) on the subnanometer scale. Calculations suggest that this may be intrinsic, energetically favored SRO rather than due to sample processing. These results offer an important demonstration that the engineered variation of participating ions in HEOs, even among those with very similar radii, provides richly diverse opportunities to control local order/disorder motifs—and therefore materials properties for future designs. This work also hints at the exquisite level of detail that may be needed in computational and experimental data analysis to guide structure–property tuning in the emerging HEO materials class.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Characterizing the Potential for Injection-Induced Fault Reactivation Through Subsurface Structural Mapping and Stress Field Analysis, Wellington Field, Sumner County, Kansas: Injection-Induced Fault Slip, Kansas

Kansas, like other parts of the central U.S., has experienced a recent increase in seismicity. Correlation of these events with brine disposal operations suggests pore fluid pressure increases are reactivating preexisting faults, but rigorous evaluation at injection sites is lacking. Here we determine the suitability of CO 2 injection into the Cambrian-Ordovician Arbuckle Group for long-term storage and into a Mississippian reservoir for enhanced oil recovery in Wellington Field, Sumner County, Kansas. To determine the potential for injection-induced earthquakes, we map subsurface faults and estimate in situ stresses, perform slip and dilation tendency analyses to identify well-oriented faults relative to the estimated stress field, and determine the pressure changes required to induce slip at reservoir and basement depths. Three-dimensional seismic reflection data reveal 12 near-vertical faults, mostly striking NNE, consistent with nodal planes from moment tensor solutions from recent earthquakes in the region. Most of the faults cut both reservoirs and several clearly penetrate the Precambrian basement. Drilling-induced fractures (N = 40) identified from image logs and inversion of earthquake moment tensor solutions (N = 65) indicate that the maximum horizontal stress is approximately EW. Slip tendency analysis indicates that faults striking <020° are stable under current reservoir conditions, whereas faults striking 020°–049° may be prone to reactivation with increasing pore fluid pressure. Although the proposed injection volume (40,000 t) is unlikely to reactive faults at reservoir depths, high-rate injection operations could reach pressures beyond the critical threshold for slip within the basement, as demonstrated by the large number of injection-induced earthquakes west of the study area.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

Development of High Energy Density Diaminocyclopropenium‐Phenothiazine Hybrid Catholytes for Non‐Aqueous Redox Flow Batteries

Abstract This report describes the design of diaminocyclopropenium‐phenothiazine hybrid catholytes for non‐aqueous redox flow batteries. The molecules are synthesized in a rapid and modular fashion by appending a diaminocyclopropenium (DAC) substituent to the nitrogen of the phenothiazine. Combining a versatile C‐N coupling protocol (which provides access to diverse derivatives) with computation and structure‐property analysis enabled the identification of a catholyte that displays stable two‐electron cycling at potentials of 0.64 and 1.00 V vs. Fc/Fc + as well as high solubility in all oxidation states (≥0.45 M in TBAPF 6 /MeCN). This catholyte was deployed in a high energy density two‐electron RFB, exhibiting >90 % capacity retention over 266 hours of flow cell cycling at >0.5 M electron concentration.

Yan, Yichao↗
DOE OSTI2021

Development of High Energy Density Diaminocyclopropenium-Phenothiazine Hybrid Catholytes for Non-Aqueous Redox Flow Batteries

Our work describes the design of diaminocyclopropenium-phenothiazine hybrid catholytes for non-aqueous redox flow batteries. The molecules are synthesized in a rapid and modular fashion by appending a diaminocyclopropenium (DAC) substituent to the nitrogen of the phenothiazine. Combining a versatile C-N coupling protocol (which provides access to diverse derivatives) with computation and structure-property analysis enabled the identification of a catholyte that displays stable two-electron cycling at potentials of 0.64 and 1.00 V vs. Fc/Fc + as well as high solubility in all oxidation states (≥0.45 M in TBAPF 6 /MeCN). This catholyte was deployed in a high energy density two-electron RFB, exhibiting >90 % capacity retention over 266 hours of flow cell cycling at >0.5 M electron concentration.

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

Mo 3 S 13 Chalcogel: A High-Capacity Electrode for Conversion-Based Li-Ion Batteries

Despite large theoretical energy densities, metal-sulfide electrodes for energy storage systems face several limitations that impact the practical realization. Here, we present the solution-processable, room temperature (RT) synthesis, local structures, and application of a sulfur-rich Mo 3 S 13 chalcogel as a conversion-based electrode for lithium-sulfide batteries (LiSBs). The structure of the amorphous Mo 3 S 13 chalcogel is derived through operando Raman spectroscopy, synchrotron X-ray pair distribution function (PDF), X-ray absorption near edge structure (XANES), and extended X-ray absorption fine structure (EXAFS) analysis, along with ab initio molecular dynamics (AIMD) simulations. A key feature of the three-dimensional (3D) network is the connection of Mo 3 S 13 units through S–S bonds. Li/Mo 3 S 13 half-cells deliver initial capacity of 1013 mAh g –1 during the first discharge. After the activation cycles, the capacity stabilizes and maintains 312 mAh g –1 at a C/3 rate after 140 cycles, demonstrating sustained performance over subsequent cycling. Such high-capacity and stability are attributed to the high density of (poly)sulfide bonds and the stable Mo–S coordination in Mo 3 S 13 chalcogel. Importantly, these findings showcase the potential of Mo 3 S 13 chalcogels as metal-sulfide electrode materials for LiSBs.

25 ENERGY STORAGE↗
DOE OSTI2019

Biochemical and structural characterization of two variants of uncertain significance in the PMS2 gene

Lynch syndrome (LS) is an autosomal dominant inherited disorder that is associated with an increased predisposition to certain cancers caused by loss-of-function mutations in one of four DNA mismatch repair (MMR) genes (MLH1, MSH2, MSH6, or PMS2). The diagnosis of LS is often challenged by the identification of missense mutations where the functional effects are not known. These are termed variants of uncertain significance (VUSs) and account for 20%–30% of noncoding and missense mutations. VUSs cause ambiguity during clinical diagnosis and hinder implementation of appropriate medical management. In this work, we focus on the functional and biological consequences of two nonsynonymous VUSs in PMS2. These variants, c.620G>A and c.123_131delGTTAGTAGA, result in the alteration of glycine 207 to glutamate (p.Gly207Glu) and the deletion of amino acid residues 42–44 (p.Leu42_Glu44del), respectively. While the PMS2 p.Gly207Glu variant retains in vitro MMR and ATPase activities, PMS2 p.Leu42_Glu44del appears to lack such capabilities. Structural and biophysical characterization using circular dichroism, small-angle X-ray scattering, and X-ray crystallography of the N-terminal domain of the PMS2 variants indicate that the p.Gly207Glu variant is properly folded similar to the wild-type enzyme, whereas p.Leu42_Glu44del is disordered and prone to aggregation.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2019

Crystal Phase Distribution and Ferroelectricity in Ultrathin HfO 2 –ZrO 2 Bilayers

(Hf,Zr)O 2 ultrathin films are used as ferroelectric layers in emerging digital logic and nonvolatile memory devices. The ferroelectric properties of (Hf,Zr)O 2 can be improved by interface engineering, such as the formation of nanolaminates with distinct HfO 2 and ZrO 2 layers. Herein, the ferroelectric performance of HfO 2 –ZrO 2 ultrathin bilayer devices is shown to depend on the stacking order of HfO 2 and ZrO 2 , which affects the quantity of the noncentrosymmetric orthorhombic Pca 2 1 crystal phase. By combining X‐ray diffraction with a novel extended X‐ray absorption fine structure (EXAFS) analysis procedure, the orthorhombic, tetragonal, and monoclinic phase fractions are quantified for bilayers composed of 3 nm HfO 2 and 3 nm ZrO 2 . A significantly larger orthorhombic ZrO 2 phase fraction is found when ZrO 2 has an unconstrained surface during annealing, whereas the presence of a ZrO 2 interface with the substrate results in a substantial tetragonal ZrO 2 phase fraction and a 2.4× smaller remanent polarization. HfO 2 is found to be less susceptible than ZrO 2 to crystal phase templating. The methods presented herein enable mechanistic studies of ferroelectric wake‐up, fatigue, and processing effects in (Hf,Zr)O 2 films, accelerating the development of electronic devices that rely on ferroelectric oxides.

McBriarty, Martin E.↗
DOE OSTI2019

Risk Assessment of Hydrogen Fuel Cell Electric Vehicles in Tunnels

The need to understand the risks and implications of traffic incidents involving hydrogen fuel cell electric vehicles in tunnels is increasing in importance with higher numbers of these vehicles being deployed. A risk analysis was performed to capture potential scenarios that could occur in the event of a crash and provide a quantitative calculation for the probability of each scenario occurring, with a qualitative categorization of possible consequences. The risk analysis was structured using an event sequence diagram with probability distributions on each event in the tree and random sampling was used to estimate resulting probability distributions for each end-state scenario. Here, the most likely consequence of a crash is no additional hazard from the hydrogen fuel (98.1–99.9% probability) beyond the existing hazards in a vehicle crash, although some factors need additional data and study to validate. These scenarios include minor crashes with no release or ignition of hydrogen. When the hydrogen does ignite, it is most likely a jet flame from the pressure relief device release due to a hydrocarbon fire (0.03–1.8% probability). This work represents a detailed assessment of the state-of-knowledge of the likelihood associated with various vehicle crash scenarios. This is used in an event sequence framework with uncertainty propagation to estimate uncertainty around the probability of each scenario occurring.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2018

Electronic and Magnetic Investigations on Fe{sub 2}NiTe Alloy with High Curie Temperature

Full-potential local-orbital minimum-basis and spin-polarized relativistic Korringa-Kohn-Rostoker along with Monte Carlo simulations are applied to study the electronic and magnetic properties of Fe{sub 2}NiTe with Hg{sub 2}CuTi structure. The analysis of orbital population shows the electrons of 4s, 3d, 4d, and 4p from transition metal and 5s, 5d, and 5p from Te atom participating in bonding. It is demonstrated by the density of states of d-d and p-d hybridizations. Calculations show the magnetic moment is carried mainly by Fe atoms. Accordingly, the exchanges of Fe constituents play a leading role in interactions. By using the calculated Heisenberg exchange coupling parameters, the Curie temperature is estimated to be 761.38 K within mean-field approximation. In order to obtain more accurate value of the Curie temperature, Monte Carlo method is adopted to model the normalized magnetization as functions of the temperature, the obtained 507.93 K value is noticeably higher than the room temperature, which is favorable in realistic spintronics application. Finally, the magnetic moments, exchange interactions, and Curie temperatures in the range of 5.4 to 6.5 Å are calculated; the results implies the Curie temperatures are still above room temperature between given lattice intervals.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2026

Evaluating ecosystem water use efficiency under drought stress: a case study of the Helan Mountain region, northwest China

Context Water use efficiency (WUE) is a fundamental ecological indicator links carbon assimilation and water loss in terrestrial ecosystems. Understanding its responses to drought stress is essential for adaptive ecosystem management, particularly in climate-sensitive mountain landscapes. Objectives This study aimed to investigate drought-driven variations in WUE across major vegetation types in the Helan Mountain region of Northwest China. Specifically, we sought to identify dominant ecological drivers of WUE variability and to disentangle their relative importance and causal pathways. Methods We quantified WUE using the Moderate Resolution Imaging Spectroradiometer (MODIS) products and the Drought Severity Index (DSI) data from 2001 to 2020. To examine WUE – drought relationships across contrasting vegetation types, we employed a spatially explicit analytical framework integrating Random Forest (RF) modeling, partial correlation analysis, and structural equation modeling (SEM). Results Regional WUE exhibited relatively stable interannual dynamics, yet pronounced spatial heterogeneity that was strongly modulated by drought conditions. Vegetation properties, particularly Leaf Area Index (LAI) and Normalized Difference Vegetation Index (NDVI), emerged as the dominant determinants of WUE, with NDVI alone explaining over 20% of its spatial variance in forest and grassland during non-drought periods. SEM analyses revealed that climate forcing influenced WUE mainly through indirect pathways mediated by soil moisture availability and vegetation structural dynamics, rather than through direct climatic controls. Among all regulating factors, LAI acted as the central control node governing ecosystem carbon–water coupling. In contrast, short-term climatic stress, especially atmospheric demand and drought duration, exerted weak or negative direct effects on WUE. Ecosystem-specific responses were observed, with croplands mainly regulated by soil water availability, whereas forests and grasslands showed more sensitive to atmospheric drought stress. Together, these results reveal a hierarchical control framework where soil–vegetation interactions mediate climate impacts on WUE, driving strong spatial heterogeneity in drought responses across mountain landscapes. Conclusions Our findings highlight the pivotal role of indirect drought effects mediated by vegetation and soil processes in shaping ecosystem WUE. The identified soil–vegetation–climate regulatory hierarchy provides mechanistic insight into landscape–scale drought sensitivity and supports integrated modeling approaches for evaluating ecosystem resilience and sustainable management in arid mountain regions.

China↗
DOE OSTI2018

Properties of Gallium Oxide Films Obtained by HF-Magnetron Sputtering

The results of an analysis of structure and phase composition of gallium oxide films obtained by HF-magnetron sputtering are presented. It is shown that in the interval 290–350 K, the increase in the film conductivity with increasing temperature is due to the excitation of electrons from a local level Е{sub t} located 0.95 eV below the conduction band bottom.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2023

Separation of K + and Bi 3+ displacements in a Pb-free, monoclinic piezoelectric at the morphotropic phase boundary

The best piezoelectric properties of any perovskite oxide known are found in the solid solution of the relaxor Pb (Mg 1/3 Nb 2/3 )O 3 and ferroelectric PbTiO 3 . Despite its impressive properties, this system has limited analogy. We present the compositional exploration of the Pb-free analogue (1-x)(K 1/2 Bi 1/2 )(Mg 1/3 Nb 2/3 )O 3 -x(K 1/2 Bi 1/2 )TiO 3 (KBMN-KBT). We locate the morphotropic phase boundary between x = 0.86 and 0.88 changing from Cm to Pm symmetry and the optimally performing composition at x = 0.88. We report a piezoelectric figure of merit (d 33 *) of 192 pm V —1 from strain measurements. Diffraction methods reveal disordered displacements of K + and Bi 3+ which persist from the KBMN endmember through multiple changes in symmetry. Rearrangement of the Bi 3+ displacements along the uncommon [011] c direction drives the physical response. Ferroelectric, dielectric, and piezoresponse force microscopy are used to study the progression of physical properties through the MPB and attribute the mechanism to a polarization rotation. Taking account for local, short-range, and average structural features yield a balanced perspective on the structure and properties of this system, isolating the driving force within this system to the Bi 3+ bonding configuration. This work yields a strong analogy to the Pb-based analogue, and provides strategies for further optimization.

36 MATERIALS SCIENCE↗
DOE OSTI2022

What explains the year-to-year variation in growing season timing of boreal black spruce forests?

Amplified climate warming in high latitudes is expected to affect growing season timing of the vast boreal biome. It is unclear whether the presence of permafrost (perennially frozen ground) might have an influence on changes in growing season timing. Here, this study examined how different environmental variables explained, either directly or indirectly, the variation in growing season timing of boreal forest stands with and without permafrost. We expected that environmental variables explaining the variation in growing season timing differed or had different explanatory power depending on permafrost presence or absence. The growing season was delineated from daily gross primary productivity (GPP) time series derived from 40 site-year data of net ecosystem carbon dioxide exchange measured with eddy covariance techniques over five black spruce (Picea mariana [Mill.])-dominated boreal forest stands in North America. In permafrost-free forest stands, a combination of start in canopy ‘green-up’ in spring and the timing of air and soil temperature increasing above freezing explained the start-of-season (SOS GPP ). Results from commonality analysis and structural equation modeling suggest that canopy ‘green-up’ and air temperature directly affected SOS GPP in permafrost-free forest stands. In addition, soil temperature acted as mediator for an indirect effect of air temperature on SOS GPP . In contrast, none of the environmental variables, or their combination, explained the variation in SOS GPP in forest stands with permafrost. The explanatory power of environmental variables was more consistent regarding the end-of-season (EOS GPP ). In both, forest stands with and without permafrost, EOS GPP was directly explained by mean soil water content in the fall and the first day of continuous snowpack formation. A better understanding how environmental variables control SOS GPP and EOS GPP in forest stands with and without permafrost will help to refine parameterizations of the boreal biome in Earth system models.

54 ENVIRONMENTAL SCIENCES↗