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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 973 records · Page 54
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Influence of ambient gas on self-reversal in Li transitions relevant to isotopic analysis

Laser induced breakdown spectroscopy is a promising, rapid analysis method for the detection and quantification of Li and its isotopes needed in geochemical, nuclear, and energy storage applications. However, spectral broadening in laser produced plasmas, presence of fine and hyperfine structures, and self-reversal effects make Li isotopic analysis via laser induced breakdown spectroscopy challenging. The present study explores the influence of Ar, N 2 , and He ambient gases over the pressure range of 0.05 - 100 Torr on line broadening and self-reversal of the Li I transition with the greatest isotopic shift in the VIS spectral region (i.e., ≈670.8 nm, ≈15.8 pm isotopic shift). We perform spatially and temporally resolved optical emission spectroscopy of plasmas produced via laser ablation of LiAlO 2 substrates. Our results show that the self-reversal and linewidth is reduced at lower pressures for all gases, and using optimized plasma conditions with chemometric methods, the 6 Li/ 7 Li isotopic ratios can be predicted.

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

Phylogeny-corrected identification of microbial gene families relevant to human gut colonization

The mechanisms by which different microbes colonize the healthy human gut versus other body sites, the gut in disease states, or other environments remain largely unknown. Identifying microbial genes influencing fitness in the gut could lead to new ways to engineer probiotics or disrupt pathogenesis. We approach this problem by measuring the statistical association between a species having a gene and the probability that the species is present in the gut microbiome. The challenge is that closely related species tend to be jointly present or absent in the microbiome and also share many genes, only a subset of which are involved in gut adaptation. We show that this phylogenetic correlation indeed leads to many false discoveries and propose phylogenetic linear regression as a powerful solution. To apply this method across the bacterial tree of life, where most species have not been experimentally phenotyped, we use metagenomes from hundreds of people to quantify each species’ prevalence in and specificity for the gut microbiome. This analysis reveals thousands of genes potentially involved in adaptation to the gut across species, including many novel candidates as well as processes known to contribute to fitness of gut bacteria, such as acid tolerance in Bacteroidetes and sporulation in Firmicutes. We also find microbial genes associated with a preference for the gut over other body sites, which are significantly enriched for genes linked to fitness in an in vivo competition experiment. Finally, we identify gene families associated with higher prevalence in patients with Crohn’s disease, including Proteobacterial genes involved in conjugation and fimbria regulation, processes previously linked to inflammation. These gene targets may represent new avenues for modulating host colonization and disease. Our strategy of combining metagenomics with phylogenetic modeling is general and can be used to identify genes associated with adaptation to any environment.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2015

Use of 16S rRNA gene for identification of a broad range of clinically relevant bacterial pathogens

According to World Health Organization statistics of 2011, infectious diseases remain in the top five causes of mortality worldwide. However, despite sophisticated research tools for microbial detection, rapid and accurate molecular diagnostics for identification of infection in humans have not been extensively adopted. Time-consuming culture-based methods remain to the forefront of clinical microbial detection. The 16S rRNA gene, a molecular marker for identification of bacterial species, is ubiquitous to members of this domain and, thanks to ever-expanding databases of sequence information, a useful tool for bacterial identification. In this study, we assembled an extensive repository of clinical isolates (n = 617), representing 30 medically important pathogenic species and originally identified using traditional culture-based or non-16S molecular methods. This strain repository was used to systematically evaluate the ability of 16S rRNA for species level identification. To enable the most accurate species level classification based on the paucity of sequence data accumulated in public databases, we built a Naïve Bayes classifier representing a diverse set of high-quality sequences from medically important bacterial organisms. We show that for species identification, a model-based approach is superior to an alignment based method. Overall, between 16S gene based and clinical identities, our study shows a genus-level concordance rate of 96% and a species-level concordance rate of 87.5%. We point to multiple cases of probable clinical misidentification with traditional culture based identification across a wide range of gram-negative rods and gram-positive cocci as well as common gram-negative cocci.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2021

Time-series dissolved oxygen, other bigeochemically-relevant analytes, and pressure gradients associated with the manuscript “Dissolved oxygen sensor in an automated hyporheic sampling system reveals biogeochemical dynamics”

This dataset contains time-series data from a vertical profile within the bed and banks of the Columbia river near Richland, WA. Water was sampled through 3 small tubes embedded in the sediment at 50,100, and 200 cm below the sediment-water interface. The goal of this study was to observe the correlations between hydraulic drivers and biogeochemical responses. The results of this study are published in the manuscript “Dissolved oxygen sensor in an automated hyporheic sampling system reveals biogeochemical dynamics”. The file types included in the data package are all time-series spreadsheet data, including hydraulic head gradients, physical parameters (temperature, pressure, SpC (specific conductivity)), and biogeochemical parameters (dissolved oxygen, pH, NO3 (nitrate) and ORP (oxidation-reduction potential)).

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

3D printing of biomedically relevant polymer materials and biocompatibility

Research on polymer materials for additive manufacturing technology in biomedical applications is as promising as it is numerous, but biocompatibility of printable materials still remains a big challenge. Changes occurring during the 3D-printing processes itself may have adverse effects on the compatibility of the completed print. Furthermore, this prospective will put emphasis on the different additives and processes that can have a direct impact on biocompatibility during and after 3D printing of polymer materials.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Deformation and strength of mantle relevant garnets: Implications for the subduction of basaltic-rich crust

Garnet is an important mineral phase in the upper mantle as it is both a key component in bulk mantle rocks, and a primary phase at high pressure within subducted basalt. In this work, we focus on the strength of garnet and the texture that develops within garnet during accommodation of differential deformational strain. We use X-ray diffraction in a radial geometry to analyze texture development in situ in three garnet compositions under pressure at 300 K: a natural garnet (Prp 60 Alm 37 ) to 30 GPa, and two synthetic majorite-bearing compositions (Prp 59 Maj 41 and Prp 42 Maj 58 ) to 44 GPa. All three garnets develop a modest (100) texture at elevated pressure under axial compression. Elasto-viscoplastic self-consistent (EVPSC) modeling suggests that two slip systems are active in the three garnet compositions at all pressures studied: {110}<$1\bar{1}1$> and {001}<110>. We determine a flow strength of ~5 GPa at pressures between 10 to 15 GPa for all three garnets; these values are higher than previously reported yield strengths measured on natural and majoritic garnets. Strengths calculated using the experimental lattice strain differ from the strength generated from those calculated using EVPSC. Prp 67 Alm 33 , Prp 59 Maj 41 , and Prp 42 Maj 58 are of comparable strength to each other at room temperature, which indicates that majorite substitution does not greatly affect the strength of garnets. Additionally, all three garnets are of similar strength as lower mantle phases such as bridgmanite and ferropericlase, suggesting that garnet may not be notably stronger than the surrounding lower mantle/deep upper mantle phases at the base of the upper mantle.

58 GEOSCIENCES↗
DOE OSTI2011

Identification of Molecular and Cellular Responses of Desulfovibrio vulgaris Biofilms under Culture Conditions Relevant to Field Conditions for Bioreduction of Toxic Metals and Radionuclides

Our findings demonstrated that D. vulgaris surface-adhered populations produce extracellular structures, and that that the cells have altered carbon and energy flux compared to planktonic cells. Biofilms did not have greatly increased carbohydrate accumulation. Interestingly genes present on the native plasmid found in D. vulgaris Hildenborough were necessary for wild type biofilm formation. In addition, extracellular appendages dependent on functions or proteins encoded by flaG or fliA also contributed to biofilm formation. Studies with SRB biofilms have indicated that the reduction and precipitation of metals can occur within the biofilm matrix; however, little work has been done to elucidate the physiological state of surface-adhered cells during metal reduction (Cr6+, U6+) and how this process is affected by nutrient feed levels (i.e., the stimulant).

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2012

Fundamental Studies of Charge Migration and Delocalization Relevant to Solar Energy Conversion

This program aimed to understand the molecular-level principles by which complex chemical systems carry out photochemical charge separation, transport, and storage, and how these insights could impact the design of practical solar energy conversion and storage devices. Towards these goals, this program focused on: (1) carrying out fundamental mechanistic and transient dynamical studies of proton-coupled electron-transfer (PCET) reactions; (2) characterizing and interrogating via electron paramagnetic resonance (EPR) spectroscopic methods novel conjugated materials that feature large charge delocalization lengths; and (3) exploring excitation delocalization and migration, as well as polaron transport properties of meso-scale assemblies that are capable of segregating light-harvesting antennae, nanoscale wire-like conduction elements, and distinct oxidizing and reducing environments.

14 SOLAR ENERGY↗
DOE OSTI2011

Irradiation Planning for Fully-Ceramic Micro-encsapsulated fuel in ATR at LWR-relevant conditions: year-end report on FY-2011

This report presents the estimation of required ATR irradiation levels for the DB-FCM fuel design (fueled with Pu and MAs). The fuel and assembly designs are those considered in a companion report [R. S. Sen et al., FCR&D-2011- 00037 or INL/EXT-11-23269]. These results, pertaining to the DB-FCM fuel, are definitive in as much as the design of said fuel is definitive. In addition to the work performed, as required, for DB-FCM fuel, work has started in a preliminary fashion on single-cell UO2 and UN fuels. These latter activities go beyond the original charter of this project and although the corresponding work is incomplete, significant progress has been achieved. However, in this context, all that has been achieved is only preliminary because the corresponding fuel designs are neither finalized nor optimized. In particular, the UO2 case is unlikely to result in a viable fuel design if limited to enrichment at or under 20 weight % in U-235. The UN fuel allows reasonable length cycles and is likely to make an optimal design possible. Despite being limited to preliminary designs and offering only preliminary conclusions, the irradiation planning tasks for UO2 and UN fuels that are summarized in this report are useful to the overall goal of devising and deploying FCM-LWR fuel since the methods acquired and tested in this project and the overall procedure for planning will be available for planning tests for the finalized fuel design. Indeed, once the fuel design is finalized and the expected burnup level is determined, the methodology that has been assembled will allow the prompt finalization of the neutronic planning of the irradiation experiment and would provide guidance on the expected experimental performance of the fuel. Deviations from the expected behavior will then have to be analyzed and the outcome of the analysis may be corrections or modifications for the assessment models as well as, possibly, fuel design modifications, and perhaps even variation of experimental control for future experimental phases. Besides the prediction of irradiation times, preliminary work was carried out on other aspects of irradiation planning. In particular, a method for evaluating the interplay of depletion, material performance modeling and irradiation is identified by reference to a companion report. Another area that was addressed in a preliminary fashion is the identification and selection of a strategy for the physical and mechanical design of the irradiation experiments. The principal conclusion is that the similarity between the FCM fuel and the fuel compacts of the Next Generation Nuclear Plant prismatic design are strong enough to warrant using irradiation hardware designs and instrumentation adapted from the AGR irradiation tests. Modifications, if found necessary, will probably be few and small, except as pertains to the water environment and its implications on the use of SiC cladding or SiC matrix with no additional cladding.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2011

Review of Recent Literature Relevant to the Environmental Effects of Marine and Hydrokinetic Energy Devices, Task 2.1.3: Effects on Aquatic Organisms – Fiscal Year 2011 Progress Report Environmental Effects of Marine and Hydrokinetic Energy

A literature search was conducted by using the Web of Science® Databases component of the ISI Web of KnowledgeSM to identify recent articles that would be useful to help assess the potential environmental effects of renewable energy development in the ocean, with emphasis on marine mammals, seabirds, and fish. Several relatively recent general review articles that included possible effects of marine renewable energy devices on marine mammals and seabirds were examined to begin the search process (e.g., Boehlert et al. 2008; Thompson et al. 2008; Simas et al. 2009). From these articles, several general topics of potential environmental effects on marine mammals, seabirds, and fish were derived. These topics were used as the primary search factors. Searches were conducted with reference to the potential effects of offshore wind farms and MHK devices on marine mammals, seabirds, and fish. Additional sources were identified by cross-checking the Web of Science databases for articles that cited the review articles. It also became clear that often the potential effects were offered as hypotheses that often were not supported by the presentation of appropriate documentation. Therefore, the search was refined and focused on trying to obtain the necessary information to support or challenge a proposed potential effect to a specific concern. One of the expressed concerns regarding MHK devices is that placing wave parks in coastal waters could compromise the migration patterns of whales. Disruption of the annual migration of the gray whale (Eschrichtius robustus), which swims at least 30,000 km on its round trip from breeding grounds in Baja California to feeding areas in the Bering Sea, is of particular concern. Among the hypothesized effects on the migrating gray whales are increased predation risk by constricting migration corridor to between array and shore or by forcing the whales to swim into deeper waters, increased metabolic energy costs and delays in reaching the destinations, and interrupting feeding by blocking access to benthic areas under arrays. The literature search focused on identifying published studies that could provide information to evaluate these concerns. The results were developed into a case study that evaluated the potential effects of the placement of wave parks in coastal waters along the migration route of the gray whale. Wave parks and other MHK arrays may have additional effects on gray whales and other marine mammals, including entanglement in mooring lines and interference with communications among other effects, that were not included in this case study. The case study results were rewritten into a simpler form that would be suitable for placement on a web blog

Kropp, Roy K.↗
DOE OSTI2012

Detailed Database Survey for DT-Fusion-Neutron-Induced Gamma-Rays relevant to THD-filled Ge-doped Plastic Capsules on the NIF

Based on Monte Carlo calculations with new cross sections and level scheme information from BNL nuclear data center, we made detailed studies about 14 MeV neutrons induced gamma rays in hydrogen, deuterium, tritium, carbon and oxygen isotopes. These results will help us in gamma reaction history diagnostic measurement with gas Cherenkov detector (GCD) for NIF THD capsule experiment.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2012

The Effects of Electrostatic Discharge Phenomena on Detonator Response: A Framework for Evaluating Parameters Relevant to Quantification of Margins and Uncertainties

Los Alamos National Laboratory (LANL), Lawrence Livermore National Laboratory (LLNL), and Pantex are collaborating on a Nuclear Safety Research & Development (NSR&D) project to develop a common Quantification of Margins and Uncertainties (QMU) framework for explosive safety analysis. An analysis of electrostatic discharge (ESD) data serves as an initial test case for methodology development. This analysis examines measurements of electrical characteristics of production environments, tests designed to measure ESD response of detonators, and information on interactions between variables drawn from expert knowledge and physics models.

42 ENGINEERING↗
DOE OSTI2012

Study of Nonlinear Evolution of the Weibel-like Instability of Relativistic Electron Beams Relevant to Fast Ignition and Astrophysics

Relativistic laser matter interaction generates an intense fast electron beam with Mega ampere (MA) to Giga-ampere current. Such beam can propagate into high-density plasmas as background plasma electrons can provide sufficient return current to maintain charge and current neutrality. However, such system is subject to Weibel-like filamentation instabilities that break out the beam into filaments and generate intense magnetic fields. This could result in anomalous stopping and large angular spread of the electron beams, leading to a lower energy coupling to the fuel in the fast ignition (FI) scheme of inertial confinement fusion, therefore, of significant interest to FI. Understanding the nonlinear growth of the Weibel B-fields and its structure is also important to astrophysics as it is generally accepted to be responsible for relativistic collisionless shocks and cosmic rays and “jitter” radiation in gamma ray burst.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2013

Review of Recent Literature Relevant to the Environmental Effects of Marine and Hydrokinetic Energy Devices; Task 2.1.3: Effects on Aquatic Organisms - Fiscal Year 2012 Progress Report

A literature search was conducted by using the Web of Science® databases component of the ISI Web of Knowledge to identify recent articles that would be useful to help assess the potential environmental effects of renewable energy development in the ocean, with emphasis on seabirds and fish. Several relatively recent general review articles that included possible effects on seabirds and fish were examined to begin the search process. From these articles, several general topics of potential environmental effects on seabirds and fish were derived. These topics were used as the primary search factors. Additional sources were identified by cross-checking the Web of Science databases for articles that cited the review articles.

Green Sturgeon↗