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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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Characterization of carbonaceous aerosols during TRACER-CAT

Absorbing aerosols (AA) have an important impact on the global radiation budget and cloud properties. The composition and properties of AA can vary substantially throughout the atmosphere, depending on the particle source and the influence of chemical aging. Uncertainties associated with the radiative effects of AA remain substantial. A key contributor to this uncertainty is understanding the extent to which coatings in general, and water uptake especially, alters absorption by AA particles and how this depends on particle composition. We deployed new and existing experimental tools during the Tracking Aerosol Convection Interactions Experiment (TRACER) campaign in Houston, TX as part of the Carbonaceous Aerosols Thrust (CAT) to provide detailed characterization of aerosol optical, chemical, and physical properties. Our TRACER-CAT measurements complemented and expanded on the planned TRACER instrumentation, allowing for more detailed characterization of aerosol properties of relevance to cloud development (a core focus of TRACER), such as the composition of particles that can act as cloud condensation nuclei, than would otherwise be available. Our measurements have allowed for assessment of the relationship(s) between AA optical properties (with a focus on absorption) and the chemical and physical characteristics (including the mixing state of black carbon (BC) containing particles). These field observations occurred in collaboration with Los Alamos National Laboratory in summer 2022 during the TRACER intensive operating period. The instrumentation we co-deployed provided for measurement of (i) multi-wavelength dry aerosol absorption, scattering, and extinction, (ii) the size-dependent composition and abundance of sub-micron aerosol, differentiating between those particles that do and do not contain BC, (iii) BC-specific concentrations and size distributions, (iv) particle size, and (v) the first field measurements at an ARM site of the influence of RH on multi-wavelength absorption by ambient AA. We have leveraged the natural variability of the atmosphere and of aerosol sources in the Houston region to (i) specifically disentangle contributions to light absorption from BC, absorbing organic carbon (brown carbon), and coatings on BC, (ii) characterize the mixing state of BC and assess the factors that give rise to compositional differences between BC-containing and BC-free aerosol, and (iii) establish how water uptake influences absorption and how any such effect depends on particle composition and BC mixing state. Overall, our study contributed to the mission of the Atmospheric System Research program in multiple ways. Through the deployment of complementary, advanced instrumentation for characterization of a wide range of aerosol properties our work helped to maximize the scientific impact of the TRACER campaign. Our work also allowed for development of new insights into the relationship(s) between aerosol composition, hygroscopicity, and the mixing state of BC with aerosol optical properties. Through this, our work has provided knowledge that can improve understanding and model representation of aerosol processes as they affect the Earth’s radiation budget.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

Evaluation of Deep Learning Model Architectures for Point-of-Care Ultrasound Diagnostics

Point-of-care ultrasound imaging is a critical tool for patient triage during trauma for diagnosing injuries and prioritizing limited medical evacuation resources. Specifically, an eFAST exam evaluates if there are free fluids in the chest or abdomen but this is only possible if ultrasound scans can be accurately interpreted, a challenge in the pre-hospital setting. In this effort, we evaluated the use of artificial intelligent eFAST image interpretation models. Widely used deep learning model architectures were evaluated as well as Bayesian models optimized for six different diagnostic models: pneumothorax (i) B- or (ii) M-mode, hemothorax (iii) B- or (iv) M-mode, (v) pelvic or bladder abdominal hemorrhage and (vi) right upper quadrant abdominal hemorrhage. Models were trained using images captured in 27 swine. Using a leave-one-subject-out training approach, the MobileNetV2 and DarkNet53 models surpassed 85% accuracy for each M-mode scan site. The different B-mode models performed worse with accuracies between 68% and 74% except for the pelvic hemorrhage model, which only reached 62% accuracy for all model architectures. These results highlight which eFAST scan sites can be easily automated with image interpretation models, while other scan sites, such as the bladder hemorrhage model, will require more robust model development or data augmentation to improve performance. With these additional improvements, the skill threshold for ultrasound-based triage can be reduced, thus expanding its utility in the pre-hospital setting.

47 OTHER INSTRUMENTATION↗
DOE OSTI2023

Recognizability of Demographically Altered Computerized Facial Approximations in an Automated Facial Recognition Context for Potential Application in Unidentified Persons Data Repositories

This study examined the recognizability of demographically altered facial approximations for potential utility in unidentified persons tracking systems. Five computer-generated approximations were generated for each of 26 African male participants using the following demographic parameters: (i) African male (true demographics), (ii) African female, (iii) Caucasian male, (iv) Asian male, and (v) Hispanic male. Overall, 62% of the true demographic facial approximations for the 26 African male participants examined were matched to a corresponding life photo within the top 50 images of a candidate list generated from an automated blind search of an optimally standardized gallery of 6159 photographs. When the African male participants were processed as African females, the identification rate was 50%. In contrast, less congruent identification rates were observed when the African male participants were processed as Caucasian (42%), Asian (35%), and Hispanic (27%) males. The observed results suggest that approximations generated using the opposite sex may be operationally informative if sex is unknown. The performance of approximations generated using alternative ancestry assignments, however, was less congruent with the performance of the true demographic approximation (African male) and may not yield as operationally constructive data as sex-altered approximations.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2021

Design Space Exploration of Emerging Memory Technologies for Machine Learning Applications

Memory design space exploration methods study memory systems’ performances and limitations before implementation. The computer memory design space has grown exponentially because of the enormous growth of memory types, memory controllers, and application software. Computer simulators are commonly used for memory design space exploration. However, complex memory simulations take an enormous amount of time. Hence, in this paper, we proposed a machine learning-based design space exploration method for dynamic random-access memory and non-volatile memory systems. We applied our method to the CosmoGAN and LeNet applications to predict the following six memory response parameters: (i) bandwidth, (ii) power, (iii) average latency, (iv) average total latency, (v) memory reads, and (vi) memory writes. Our experimental results show that machine learning models can predict memory response parameter values faster than simulations. We used support vector machine, random forest, and gradient boosting machine learning models. We observed that the support vector machine provides better performance for bandwidth, average latency, and average total latency. The random forest model works better for memory reads and writes. The gradient boosting model provides superior prediction performance for power. We provide a detailed discussion on learning curve characteristics, error analysis, and memory type recommendation.

Hasan, S M Shamimul↗
DOE OSTI2021

Coated semiconductor particles and methods of making the same

The present disclosure relates to an electrode material that includes a solid core particle having an outer surface and including at least one of a Group II element, a Group III element, a Group IV element, a Group V element, and/or a Group VI element, and a layer including a polymer, where the solid core particle has a characteristic length between greater than zero nanometers and 1000 nm, the layer substantially covers all of the outer surface, the layer has a thickness between greater than zero nanometers 100 nm, and the layer is capable of elastically stretching as a result of expansion and contraction by the solid core.

Ban, Chunmei↗
DOE OSTI2020

Hydrolysis of Metal Dioxides Differentiates d-block from f-block Elements: Pa(V) as a 6d Transition Metal; Pr(V) as a 4f “Lanthanyl”

Gas-phase reactions of pentavalent metal dioxide cations M V O 2 + with water were studied experimentally for M = V, Nb, Ta, Pr, Pa, U, Pu, and Am. Addition of two H 2 O can occur by adsorption to yield hydrate (H 2 O) 2 M V O 2 + or by hydrolysis to yield hydroxide M V (OH) 4 + . Displacement of H 2 O by acetone indicates hydrates for Pr V , U V , Pu V , and Am V , whereas nondisplacement indicates hydroxides for Nb V , Ta V , and Pa V . Computed potential energy profiles agree with the experimental results and furthermore indicate that acetone unexpectedly induces dehydrolysis and displaces two H 2 O from (H 2 O)VO(OH) 2 + to yield (acetone) 2 VO 2 + . Structures and energies for several M V , as well as for Th IV and U VI , indicate that hydrolysis is governed by the involvement of valence f versus d orbitals in bonding: linear f-element dioxides are more resistant to hydrolysis than bent d-element dioxides. Accordingly, for early actinides, hydrolysis of Th IV is characteristic of a 6d-block transition metal; hydration of U V and U VI is characteristic of 5f actinyls; and Pa V is intermediate between 6d and 5f. The praseodymium oxide cation Pr V O 2 + is assigned as an actinyl-like lanthanyl with properties governed by 4f bonding.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Testbed and Experiments for Quantum-Conventional Networking

The realization of quantum networks requires the development of devices and methods unprecedented in conventional networks, and yet they critically depend on the latter for implementing foundational blocks and essential operations. We describe a testbed to support the development and testing of their functionality and performance by providing quantum and conventional data planes and devices, together with a secure conventional control plane. It incorporates a variety of entangled photon sources, qubit technologies, detector technologies, photonic components, and supporting conventional switches and workstations. It implements a novel fiber telescoping scheme that provides suites of connections using fiber spools and inground-aerial fiber loops. We briefly summarize a variety of experiments conducted over this testbed including: (i) flex-grid quantum connection experiments, (ii) quantum state and channel tomography, (iii) utilization of quantum key distribution keys to secure conventional encryption and firewall devices, (iv) comparative study of analytical capacity estimates and entanglement throughput, (v) deployed squeezing coexisting with conventional communications, and (iv) measurement of polarization time variation.

Rao, Nageswara [ORNL] (ORCID:0000000234085941)↗
DOE OSTI2021

Eridanus IV: an Ultra-faint Dwarf Galaxy Candidate Discovered in the DECam Local Volume Exploration Survey

We present the discovery of a candidate ultra-faint Milky-Way satellite, Eridanus IV (DELVE J0505−0931), detected in photometric data from the DECam Local Volume Exploration survey (DELVE). Eridanus IV is a faint (M V = − 4.7 ± 0.2), extended (), and elliptical (ϵ = 0.54 ± 0.1) system at a heliocentric distance of , with a stellar population that is well described by an old, metal-poor isochrone (age of τ ∼ 13.0 Gyr and metallicity of [Fe/H] ≲ − 2.1 dex). These properties are consistent with the known population of ultra-faint Milky-Way satellite galaxies. Eridanus IV is also prominently detected using proper-motion measurements from Gaia Early Data Release 3, with a systemic proper motion of mas yr−1 measured from its horizontal branch and red-giant-branch member stars. We find that the spatial distribution of likely member stars hints at the possibility that the system is undergoing tidal disruption.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2024

Reading between the (Spectral) Lines: Magellan/IMACS Spectroscopy of the Ultrafaint Dwarf Galaxies Eridanus IV and Centaurus I

Abstract We present a spectroscopic analysis of Eridanus IV (Eri IV) and Centaurus I (Cen I), two ultrafaint dwarf galaxies of the Milky Way. Using IMACS/Magellan spectroscopy, we identify 28 member stars of Eri IV and 34 member stars of Cen I. For Eri IV, we measure a systemic velocity of v sys = − 31.5 − 1.2 + 1.3 km s − 1 , and velocity dispersion σ v = 6.1 − 0.9 + 1.2 km s − 1 . Additionally, we measure the metallicities of 16 member stars of Eri IV. We find a metallicity of [ Fe / H ] = − 2.87 − 0.07 + 0.08 , and resolve a dispersion of σ [Fe/H] =0.20 ± 0.09. The mean metallicity is marginally lower than all other known ultrafaint dwarf galaxies, making it one of the most metal-poor galaxies discovered thus far. Eri IV also has a somewhat unusual right-skewed metallicity distribution. For Cen I, we find a velocity v sys = 44.9 ± 0.8 km s −1 , and velocity dispersion σ v = 4.2 − 0.5 + 0.6 km s − 1 . We measure the metallicities of 27 member stars of Cen I, and find a mean metallicity [Fe/H] = −2.57 ± 0.08, and metallicity dispersion σ [ Fe / H ] = 0.38 − 0.05 + 0.07 . We calculate the systemic proper motion, orbit, and the astrophysical J-factor for each system, the latter of which indicates that Eri IV is a good target for indirect dark matter detection. We also find no strong evidence for tidal stripping of Cen I or Eri IV. Overall, our measurements confirm that Eri IV and Cen I are dark-matter-dominated galaxies with properties largely consistent with other known ultrafaint dwarf galaxies. The low metallicity, right-skewed metallicity distribution, and high J-factor make Eri IV an especially interesting candidate for further follow-up.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2026

A Solid State Zwitterionic Plastic Crystal With High Static Dielectric Constant

Solid materials with a high dielectric constant have a wide range of applications in the energy storage field. In this research, an imidazolium-based zwitterion is designed, synthesized, and confirmed to have a plastic crystal phase based on the following experimental and computational evidence: (i) the presence of long-range order with weak intermolecular forces and competing attractive-repulsive interactions along different crystallographic directions; (ii) the observation of more than one endotherm on heating including a solid-solid phase transition at T s-s = −26 °C and melting of the plastic crystal at T m = 72°C; (iii) a low entropy of fusion at melting (2.1 JK −1 mol −1 ); (iv) a strongly anisotropic morphology; (v) relatively fast dynamics originating from short-range degrees of freedom. Furthermore, it exhibits a very high dielectric constant in the plastic crystal solid state (147 at −10°C and 103 at 70°C) due to the rotational degrees of freedom of plastic crystals that arise from weak net intermolecular interactions of zwitterions due to only having two carbons between the anion and cation. This material conveniently remains in the plastic crystal phase within 50 K of ambient temperature. This discovery opens new opportunities in the search for solid-state high dielectric constant materials.

dielectric relaxation↗
DOE OSTI2020

The effects of different types of mulch on soil properties and tea production and quality

Abstract BACKGROUND Tea is an important economic crop in China. Mulching, a modern agricultural practice, can modify the soil microenvironment and maintain the crop yield. RESULTS To investigate the effect of different mulching modes on tea plant growth, filed experiments were conducted in a Shizipu tea plantation located in Langxi Country (Xuanchen City, Anhui Province, China). Five treatments were carried out in a randomized complete block arrangement: (i) clean tillage (control); (ii) black plastic film; (iii) weed barrier fabric; (iv) rice straw mulch; and (v) intercropping with Vulpia myuros . The effects of different mulch modes on soil temperature, water moisture, soil compactness, root activity, soil enzyme activity and nutrition status on tea yield, quality and economic benefits were compared at the harvest stage. In the present study, compared with other mulch treatments, intercropping with V. myuros significantly reduced the topsoil temperature (to an optimum temperature) and soil compactness, and increased the water holding capacity in the deep soil layer, which contributed to increased tea root activity and respiration. Furthermore, intercropping with V. myuros significantly increased soil enzymes activity, soil organic matter, and the available nitrogen and phosphorus concentrations in the main root zone. Therefore, the stronger tea root activity accelerated nutrition uptake and increased the tea yield and quality‐related components of the tea, thus resulting in a larger average net income. CONCLUSION Intercropping with V. myuros could serve as a profitable agricultural method for tea production. © 2020 Society of Chemical Industry

Xianchen, Zhang↗
DOE OSTI2026

Single‐Cell Nanodroplet Processing Proteomics Pipeline for Analysis of Human‐Derived Microglia

Single-cell omics tools provide unique insights into heterogeneous cell populations and their responses to stimuli. For example, single-cell RNA sequencing has identified several transcriptionally distinct populations of microglia, which are resident immune cells of the central nervous system (CNS) that are responsive to CNS injury, infection, and neurodegeneration. To date, single-cell studies of microglia have focused on RNA-sequencing or cytometry by time of flight (CyTOF), which provide indirect readouts of protein abundance or quantification of a limited number of targets. Herein, we present a workflow based on FACS-assisted isolation, cryopreservation, and nanodroplet-based processing for single-cell mass spectrometry proteomics analysis of the postmortem human brain cortex-derived microglia. From a single microglial cell, 1039 proteins could be identified on average. As a proof-of-principle, we applied single-cell proteomics for exploring the heterogeneity of brain microglia at the cellular level. This pilot proteomics data partially recapitulates the prior microglia subtypes. Specifically, we determined that mitochondrial proteins, in particular members of NADH dehydrogenase (Complex I), cytochrome b-c1 (Complex III), cytochrome c oxidase (Complex IV), F1-ATPase (Complex V), and Na+/K+-ATPase complex, drive variation across microglia. This pipeline offers the potential for identifying functionally and analytically relevant protein targets for microglia in Alzheimer's disease and other neurological disorders.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

Highly efficient and simple SSPER and rrPCR approaches for the accurate site-directed mutagenesis of large and small plasmids

Advances are needed in the site-directed mutagenesis of large plasmids for protein structure-function studies, as current methods are often inefficient, complicated and time-consuming. Here two new methods are reported that overcome these difficulties, namely the single primer extension reaction (SSPER) strategy that reaches 100% efficiency and the reduce recycle PCR (rrPCR) method that is advantageous in generating single and pairwise combinations of mutations. Both methods are distinguished from current technologies by the addition of a step that easily removes the oligonucleotide primer(s) after the first reaction, thus allowing for the addition of a second reaction in chronological sequence to generate and isolate the appropriate DNA product with the site-directed mutation(s). High efficiency of the methods is demonstrated by generating single and paired combinations of the 11 site-directed mutations targeted on 5 different plasmid DNA templates ranging from 10 to 12 kb and 57–60% GC-content at a rate of 50–100%. Overall, the methods are demonstrated to be (i) highly accurate, allowing for screening of plasmids by DNA sequencing, (ii) streamlined to generate the mutations within a single day, (iii) cost-effective in requiring only two primers and two enzymes (DpnI and a proofreading DNA polymerase), (iv) straightforward in primer design, (v) applicable for both large and small plasmids, and (vi) easily implemented by entry level researchers.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

p-Block Metal Oxide Noninnocence in the Oxygen Evolution Reaction in Acid: The Case of Bismuth Oxide

The Pourbaix diagrams of p-block Pb, Sb, and Bi establish a robust stability for their oxides in acidic solutions. Such oxides have found utility as stable frameworks to support metals that are active for oxygen evolution reaction (OER) catalysis, but they also possess two-electron redox couples, which can potentially engender OER activity. Thus, the use of p-block oxide supports provides an imperative for understanding the OER activity of the unary oxides. Toward this end, we report BiO x films that are able to perform OER catalysis at moderate overpotentials for extended periods of operation (>110 h) in highly acidic solutions (pH 1.0–2.25) with no sign of decreased OER activity during operation at current densities of 1–5 mA cm –2 . X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), and UV-vis spectroelectrochemistry reveal a change in the Bi oxidation state prior to OER catalysis, from predominantly Bi 3+ in the as-deposited films to primarily Bi 5+ in the catalytically active films. Furthermore, this transformation is accompanied by a prominent color change from orange to dark brown. Simulations of the cyclic voltammogram catalytic profiles suggest two OER pathways for BiO x involving Bi IV O x and Bi V O x catalysts with the Bi V O x pathway prevailing after catalyst activation. Together, these results demonstrate the ability of BiO x to facilitate OER in acid with high functional stability and underscore the noninnocent role that p-block metal oxides may play in OER catalysis in acidic media.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Infrared Spectroscopic Observation of Oxo- and Superoxo-Intermediates in the Water Oxidation Cycle of a Molecular Ir Catalyst

Molecular Ir catalysts have emerged as an important class of model catalysts for understanding structure–activity relationships in water oxidation, a reaction that is central to renewable fuel synthesis. Prior efforts have mostly focused on controlling and elucidating the emergence of active species from prepared precursors. However, the development of efficient and stable molecular Ir catalysts also necessitates probing of reaction intermediates. To date, relatively little is known about the key intermediates in the cycles of the molecular Ir catalysts. Herein, we probed the catalytic cycle of a homogeneous Ir catalyst (“blue dimer”) at a Au electrode/aqueous electrolyte interface by combining surface-enhanced infrared absorption spectroscopy (SEIRAS) with phase-sensitive detection (PSD). Cyclic voltammograms (CVs) from 1.4 to 1.7 VRHE (RHE = reversible hydrogen electrode) give rise to a band at ~818 cm –1 , whereas CVs from 1.4 to ≥1.85 VRHE generate an additional band at ~1146 cm –1 . Isotope labeling experiments indicate that the bands at ~818 and ~1146 cm –1 are attributable to oxo (Ir V =O) and superoxo (Ir IV –OO • ) moieties, respectively. Furthermore, this study establishes PSD-SEIRAS as a sensitive tool for probing water oxidation cycles at electrode/electrolyte interfaces and demonstrates that the relative abundance of two key intermediates can be tuned by the thermodynamic driving force of the reaction.

25 ENERGY STORAGE↗
DOE OSTI2025

A Hybrid Dynamic/Steady-State Tool With Protection Simulation for Cascading-Outage Analysis of Extreme Events in Power Systems

The bulk electric power grid is subject to vulnerabilities from component outages, which in certain combinations (extreme events) might lead to cascading outages. Some of these outages can be severe enough to trigger brownouts and blackouts. Much is known about mitigating the first few failures near the beginning of a cascade, but there are few established methods and tools for directly analyzing the risks of cascading component outages over a longer time scale. Current power system tools have limited ability to perform detailed and accurate cascading-outage analysis, which could be computationally intensive. The Dynamic Contingency Analysis Tool (DCAT) enables power system planning engineers to more realistically assess the consequences of extreme contingencies and potential cascading events across their systems and interconnections. DCAT has several unique features: (i) detailed hybrid dynamic and steady-state analysis of power systems to mimic real-world cascading outages, (ii) detailed modeling of protection systems embedded in the dynamic simulation, (iii) simulation of corrective action after transients, (iv) simulation of islanding , and (v) high-performance computing capability to simulate a large number of contingencies in a reasonable time. DCAT outputs will help find technically sound solutions to reduce the risk of cascading outages. This paper provides details of DCAT methodology and shows its capabilities with extreme events on real-world cases.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2023

Utah FORGE: Optimization of a Plug-and-Perf Stimulation (Fervo Energy)

Information around the plug-and-perf treatment design at Utah FORGE by Fervo Energy. Objective and Purpose: - Develop a multistage hydraulic stimulation approach designed specifically to target the top three factors that control the technical and commercial viability of an EGS system: i) Achieving sufficient injectivity to support high cross-well flow rates ii) Distributing flow evenly across the wellbore and reservoir to maximize heat mining efficiency, ensure sustained heat transfer, and mitigate thermal breakthrough iii) Overcoming the effects of stress heterogeneity, stress shadowing, and variations in natural fracture properties during the stimulation treatment, leading to a more predictable stimulated reservoir volume and offset well placement - The following activities will be performed: i) Design, plan, and execute a multistage plug-and-perf stimulation treatment at a Fervo site with data acquisition and well testing activities aimed at addressing key technical aspects of the issues above ii) Perform data processing and interpretation of field results to translate the results form the Fervo site to a site-specific design at the Utah FORGE site iii) Design, plan, and execute a multistage plug-and-perf stimulation treatment design at the Utah FORGE site Methods and Approach: - Design a detailed data acquisition plan to maximize learning around: i) DFIT testing ii) Petrophysical logging, image logging iii) Permanent DAS/DTS fiber optic monitoring iv) Deep borehole microseismic monitoring v) Shallow borehole induced seismicity monitoring vi) Injection/production testing (RTA analysis, tracer testing) vii) Integrated numerical modeling and production forecasting

15 GEOTHERMAL ENERGY↗