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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 1,369 records · Page 76
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Study of the Decay and Production Properties of D s 1 ( 2536 ) and D s 2 * ( 2573 )

The e + e − → D s + D s 1 ( 2536 ) − and e + e − → D s + D s 2 * ( 2573 ) − processes are studied using data samples collected with the BESIII detector at center-of-mass energies from 4.530 to 4.946 GeV. The absolute branching fractions of D s 1 ( 2536 ) − → D ¯ * 0 K − and D s 2 * ( 2573 ) − → D ¯ 0 K − are measured for the first time to be ( 35.9 ± 4.8 ± 3.5 ) % and ( 37.4 ± 3.1 ± 4.6 ) % , respectively. The e + e − → D s + D s 1 ( 2536 ) − and e + e − → D s + D s 2 * ( 2573 ) − cross sections are measured, and a resonant structure at around 4.6 GeV with a width of 50 MeV is observed in both processes with a statistical significance of 7.2 σ and 15 σ , respectively. The state is observed for the first time in e + e − → D s + D s 2 * ( 2573 ) − and could be the Y ( 4626 ) found by the Belle oration in the D s + D s 1 ( 2536 ) − final state, since they have similar masses and widths. There is also evidence for a structure at around 4.75 GeV in both processes. Published by the American Physical Society 2024

Ablikim, M.↗
DOE OSTI2024

Evidence of h b ( 2 P ) → ϒ ( 1 S ) η Decay and Search for h b ( 1 P , 2 P ) → ϒ ( 1 S ) π 0 with the Belle Detector

We report the first evidence for the h b ( 2 P ) → ϒ ( 1 S ) η transition with a significance of 3.5 standard deviations. The decay branching fraction is measured to be B [ h b ( 2 P ) → ϒ ( 1 S ) η ] = ( 7.1 − 3.2 + 3.7 ± 0.8 ) × 10 − 3 , which is noticeably smaller than expected. We also set upper limits on π 0 transitions of B [ h b ( 2 P ) → ϒ ( 1 S ) π 0 ] < 1.8 × 10 − 3 , and B [ h b ( 1 P ) → ϒ ( 1 S ) π 0 ] < 1.8 × 10 − 3 , at the 90% confidence level. These results are obtained with a 131.4 fb − 1 data sample collected near the ϒ ( 5 S ) resonance with the Belle detector at the KEKB asymmetric-energy e + e − collider. Published by the American Physical Society 2024

Kovalenko, E. (ORCID:0000000180841931)↗
DOE OSTI2022

MemGaze: Rapid and Effective Load-Level Memory Trace Analysis

A major challenge of memory analysis tools is combining high-resolution analysis and low overhead measurement. Currently, hardware/software-based analysis of load-level sequences incurs time slowdowns of O(100×). We present MemGaze, a tool for low-overhead, high-resolution memory analysis. MemGaze uses Intel’s Processor Tracing (PT) instruction ptwrite to collect sampled and compressed memory address traces for load-level, sequence-aware analysis of data reuse. We describe multi-resolution analysis for locations vs. operations, accesses vs. spatio-temporal reuse, and reuse (distance, rate, volume) vs. access patterns. Both trace size and resolution are controllable. We use MemGaze to elucidate the memory effects of different data structures and algorithms. For sampled traces that are ˜1% of a full one, analysis metrics have 1-25% MAPE for histograms of varying dynamic sequence lengths. With current suboptimal kernel support (PT runs continuously), MemGaze’s time overhead is typically 10–95%; 7× at worst. However, when PT runs only during samples, overhead is 10–35% on memory intensive regions and correlates with executed ptwrites.

Kilic, Ozgur O.↗
DOE OSTI2019

Microbial communities of the Laurentian Great Lakes reflect connectivity and local biogeochemistry

The Laurentian Great Lakes are a vast, interconnected freshwater system spanning strong physicochemical gradients, thus constituting a powerful natural laboratory for addressing fundamental questions about microbial ecology and evolution. We present a comparative analysis of pelagic microbial communities across all five Laurentian Great Lakes, focusing on Bacterial and Archaeal picoplankton characterized via 16S rRNA amplicon sequencing. We collected samples throughout the water column from the major basins of each lake in spring and summer over 2 years. Two oligotypes, classified as LD12 (Alphaproteobacteria) and acI-B1 (Actinobacteria), were among the most abundant in every sample. At the same time, microbial communities showed distinct patterns with depth during summer stratification. Deep hypolimnion samples were frequently dominated by a Chloroflexi oligotype that reached up to 19% relative abundance. Stratified surface communities differed between the colder, less productive upper lakes (Superior, Michigan, Huron) and warmer, more productive lower lakes (Erie, Ontario), in part due to an Actinobacteria oligotype (acI-C2) that averaged 7.7% of sequences in the lower lakes but <0.2% in the upper lakes. Together, our findings suggest that both hydrologic connectivity and local selective pressures shape microbial communities in the Great Lakes and establish a framework for future investigations.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2025

Identifying Potential Geochemical and Microbial Impacts of Hydrogen Storage in a Deep Saline Aquifer

Hydrogen is valuable commodity and a promising energy carrier for variable energy production. Storage of hydrogen may occur through injection of hydrogen or a hydrogen/methane gas blend in subsurface reservoirs. However, the geochemical and biological reactions that may impact the stored hydrogen are not yet understood. Therefore, we collected samples from a deep storage aquifer located in the St. Peter Formation in southern Illinois. The reservoir material was primarily quartz with sulphur and iron deposits, while the major constituents of the fluid were chloride and sulphate. 16S rRNA gene amplicon sequencing revealed a low biomass microbial community that contained no obvious hydrogen-consuming bacteria. Next, we enriched a field sample to increase the biomass and completed a metagenomic analysis, finding a low number of genes present that are associated with hydrogen consumption. Then, we completed a series of reactor experiments under reservoir conditions with 15% H2/85% CH4 gas simulating a short-term hydrogen storage, high withdrawal scenario. We found minimal changes in the geochemistry or microbiology for the reactor experiments. This work suggests that short-term storage may be highly successful, although significant additional work needs to be completed in order to accurately evaluate the risks associated with long-term hydrogen storage scenarios. It is essential we continue to expand our understanding of the dynamics present in saline aquifers and provide new insights into how hydrogen storage may impact underground geological storage environments.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

Efficient species identification for Pacific salmon genetic monitoring programs

Abstract Genetic monitoring of Pacific salmon in the Columbia River basin provides crucial information to fisheries managers that is otherwise challenging to obtain using traditional methods. Monitoring programs such as genetic stock identification (GSI) and parentage‐based tagging (PBT) involve genotyping tens of thousands of individuals annually. Although rare, these large sample collections inevitably include misidentified species, which exhibit low genotyping success on species‐specific Genotyping‐in‐Thousands by sequencing (GT‐seq) panels. For laboratories involved in large‐scale genotyping efforts, diagnosing non‐target species and reassigning them to the appropriate monitoring program can be costly and time‐consuming. To address this problem, we identified 19 primer pairs that exhibit consistent cross‐species amplification among salmonids and contain 51 species informative variants. These genetic markers reliably discriminate among 11 salmonid species and two subspecies of Cutthroat Trout and have been included in species‐specific GT‐seq panels for Chinook Salmon, Coho Salmon, Sockeye Salmon, and Rainbow Trout commonly used for Pacific salmon genetic monitoring. The majority of species‐informative amplicons (16) were newly identified from the four existing GT‐seq panels, thus demonstrating a low‐cost approach to species identification when using targeted sequencing methods. A species‐calling script was developed that is tailored for routine GT‐seq genotyping pipelines and automates the identification of non‐target species. Following extensive testing with empirical and simulated data, we demonstrated that the genetic markers and accompanying script accurately identified species and are robust to missing genotypic data and low‐frequency, shared polymorphisms among species. Finally, we used these tools to identify Coho Salmon incidentally caught in the Columbia River Chinook Salmon sport fishery and used PBT to determine their hatchery of origin. These molecular and computing resources provide a valuable tool for Pacific salmon conservation in the Columbia River basin and demonstrate a cost‐effective approach to species identification for genetic monitoring programs.

Robinson, Zachary L.↗
DOE OSTI2025

Adaptation and Plasticity of Nannochloropsis sp. in Response to Seasonal and Geographic Climate Variation

Phytoplankton respond to their environment through genetic adaptation and plasticity to maintain fitness. This poses challenges when growing microalgae for industrial applications because, inherently, outdoor mass cultivation may lead to adaptations that alter desirable phenotypic traits and environmental niches. Here, we used common garden experiments to quantify the plasticity and adaptive responses to seasonal and geographic climate variation of Nannochloropsis, a microalga commonly used in biotechnology. An initially monoclonal strain was grown outdoors across four locations in Hawaii, Texas, California, and New Mexico. Following 17 and 22 months of cultivation outdoors, we collected samples during winter and summer, respectively, and we compared strains' growth from the four sites across temperature and light gradients in the laboratory. Despite hundreds of generations of exposure to divergent climates, with ~20°C and three-fold differences in daily light intensity, strains showed only minor differences in performance. Thermal performance varied more among seasons than sites, whereas light performance varied with both season and site. Our study indicates that Nannochloropsis exhibits broad plasticity in response to light and temperature, which may inhibit genetic adaptation in space or time. Highly variable field conditions, with daily and seasonal climate fluctuations, may favor plasticity and prevent the rapid adaptation often seen in laboratory studies of microorganisms in constant environments.

common garden experiment↗
DOE OSTI2018

Pre-Viking Swedish Hillfort Glass: A Prospective Long-Term Alteration Analogue for Vitrified Nuclear Waste

Examining ancient anthropogenic glasses altered in natural environments over hundreds of years can inform and verify models for predicting long-term rates of glass corrosion. Understanding corrosion mechanisms is critical for modeling the performance of nuclear waste glasses that are required to retain radionuclides for >1000 years, and will be disposed in shallow subsurface environments. Two types of ancient Swedish hillfort glasses — one clear, iron-poor glass, and one dark, iron-rich glass — have been characterized to evaluate their use as long-term alteration analogues for vitrified nuclear waste disposed under near-surface conditions. These glasses are of interest to the nuclear waste glass community as they have comparable elemental compositions to glasses under development for disposal of nuclear waste at the Hanford Site, USA. They are also of historical importance to Sweden; thus, an analysis protocol, focusing on non-destructive to semi-destructive analyses, has been developed to maintain the historical integrity of the samples. X-ray computed tomography, micro X-ray diffraction, micro X-ray fluorescence, and electron microscopy data are presented for both vitreous and mineralogical components of the hillfort samples. The internal microstructure and elemental distribution of the glasses, including the presence of crystalline inclusions, are discussed in the context of ancient glassmaking technology.

Weaver, Jamie L.↗
DOE OSTI2011

Microbial community structure of hydrothermal deposits from geochemically different vent fields along the Mid-Atlantic Ridge

To evaluate the effects of local fluid geochemistry on microbial communities associated with active hydrothermal vent deposits, we examined the archaeal and bacterial communities of 12 samples collected from two very different vent fields: the basalt-hosted Lucky Strike (37 17'N, 32 16.3'W, depth 1600-1750 m) and the ultramafic-hosted Rainbow (36 13'N, 33 54.1'W, depth 2270-2330 m) vent fields along the Mid-Atlantic Ridge (MAR). Using multiplexed barcoded pyrosequencing of the variable region 4 (V4) of the 16S rRNA genes, we show statistically significant differences between the archaeal and bacterial communities associated with the different vent fields. Quantitative polymerase chain reaction (qPCR) assays of the functional gene diagnostic for methanogenesis (mcrA), as well as geochemical modelling to predict pore fluid chemistries within the deposits, support the pyrosequencing observations. Collectively, these results show that the less reduced, hydrogen-poor fluids at Lucky Strike limit colonization by strict anaerobes such as methanogens, and allow for hyperthermophilic microaerophiles, like Aeropyrum. In contrast, the hydrogen-rich reducing vent fluids at the ultramafic-influenced Rainbow vent field support the prevalence of methanogens and other hydrogen-oxidizing thermophiles at this site. These results demonstrate that biogeographical patterns of hydrothermal vent microorganisms are shaped in part by large scale geological and geochemical processes.

58 GEOSCIENCES↗
DOE OSTI2011

Hypervelocity Capture of Meteoritic Particles in Nonsilica Aerogels

The Stardust mission captured particles from the comet 81P/Wild 2 in gradient density silica aerogel and returned the collected samples to earth in 2006. The analyses of these particles have revealed several new insights into the formation of our solar system. However, since the aerogel used as the capture material was silica, the elemental analyses of the silica-rich particles were made more complicated in certain ways due to the mixing of the silicon of the particles and that of the aerogel. By using a nonsilica aerogel, future elemental analyses of silica-rich particles captured in aerogel could be made more straightforward. Resorcinol/formaldehyde (RF), alumina, and zirconia aerogels were impact tested with meteoritic fragments and the captured fragments were mapped with synchrotron-based X-ray microprobe (XRM) and the particles were analyzed with X-ray fluorescence (XRF). The resorcinol/formaldehyde aerogel proved to be the best capture material, in that it could be keystoned and XRF could be used to locate and analyze particles that were less than 10 {micro}m.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

Hf‐W chronology of a macrochondrule from the L5/6 chondrite Northwest Africa 8192

Abstract A large, igneous‐textured, and 2 cm‐sized spherical object from the L5/6 chondrite NWA 8192 was investigated for its chemical composition, petrography, O isotopic composition, and Hf‐W chronology. The petrography and chemical data indicate that this object closely resembles commonly found chondrules in ordinary chondrites and is therefore classified as a “macrochondrule.* As a result of metal loss during its formation, the macrochondrule exhibits elevated Hf/W, which makes it possible to date this object using the short‐lived 182 Hf‐ 182 W system. The Hf‐W data provide a two‐stage model age for metal–silicate fractionation of 1.4 ± 0.6 Ma after Ca‐Al‐rich inclusion (CAI) formation, indicating that the macrochondrule formed coevally to normal‐sized chondrules from ordinary chondrites. By contrast, Hf‐W data for metal from the host chondrite yield a younger model age of ~11 Ma after CAIs. This younger age agrees with Hf‐W ages of other type 5–6 ordinary chondrites, and corresponds to the time of cooling below the Hf‐W closure temperature during thermal metamorphism on the parent body. The Hf‐W model age difference between the macrochondrule and the host metal demonstrates that the Hf‐W systematics of the bulk macrochondrule were not disturbed during thermal metamorphism, and therefore, that the formation age of such objects can still be determined even in strongly metamorphosed samples. Collectively, this study illustrates that chondrule formation was not limited to mm‐size objects, implying that the rarity of macrochondrules reflects either that this process was very inefficient, that subsequent nebular size‐sorting decimated large chondrules, or that large precursors were rare.

58 GEOSCIENCES↗
DOE OSTI2020

Community structure – Ecosystem function relationships in the Congo Basin methane cycle depend on the physiological scale of function

Belowground ecosystem processes can be highly variable and difficult to predict using microbial community data. Here, we argue that this stems from at least three issues: (a) complex covariance structure of samples (with environmental conditions or spatial proximity) can make distinguishing biotic drivers a challenge; (b) communities can control ecosystem processes through multiple mechanisms, making the identification of these controls a challenge; and (c) ecosystem function assessments can be broad in physiological scale, encapsulating multiple processes with unique microbially mediated controls. In this work, we test these assertions using methane (CH 4 )-cycling processes in soil samples collected along a wetland-to-upland habitat gradient in the Congo Basin. We perform our measurements of function under controlled laboratory conditions and statistically control for environmental covariates to aid in identifying biotic drivers. We divide measurements of microbial communities into four attributes (abundance, activity, composition, and diversity) that represent different forms of community control. Lastly, our process measurements differ in physiological scale, including broader processes (gross methanogenesis and methanotrophy) that involve more mediating groups, to finer processes (hydrogenotrophic methanogenesis and high-affinity CH 4 oxidation) with fewer mediating groups. We observed that finer scale processes can be more readily predicted from microbial community structure than broader scale processes. In addition, the nature of those relationships differed, with broad processes limited by abundance while fine-scale processes were associated with diversity and composition. These findings demonstrate the importance of carefully defining the physiological scale of ecosystem function and performing community measurements that represent the range of possible controls on ecosystem processes.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2013

Risk reporting in the Chinese news media in response to radiation threat from the Fukushima nuclear reactor crisis

On March 11, 2011, the northeastern coast of Japan was struck by 9.0-magnitude earthquake that triggered a devastating tsunami. Aside from the huge toll in people's lives and severe damages to property, the tremor sent the Fukushima Daiichi Nuclear Power Plant on a tailspin, causing hydrogen explosions in three reactors, and sending radioactive materials into the air and bodies of water. Declared the largest nuclear disaster since Chernobyl, the crisis threatened neighboring countries, including China (International Business Times, 2011). On March 28, low levels of iodine-131, cesium-137 and strontium, believed to have drifted from Japan, were detected in the air over Heilongjiang province in the northeast part of China and in seawater samples collected in the eastern coastal areas (Qianjiang Eve News, 2011). Because these chemicals can enter the food chain and adversely affect human health (Ifeng.com, 2011), people became understandably anxious and the government had to avert panic. This study asks: How did the Chinese media report the risks attendant to this event? A content analysis of 45 straight news reports published by the Chinese press from March 16, 2011 to April 25, 2011 was conducted. The analysis focused on how the media explained the risk, portrayed potential harm, reported on government actions to safeguard public health, and provided suggestions to reduce public fear. The sources of information cited in the reports were also identified. The articles examined were collected from People.com, a comprehensive online archive of news reports, using 'Fukushima' and 'nuclear radiation' as search terms. The results indicated journalistic practices that left much to be desired in terms of risk reporting. First, the articles explained little about the technical aspects of the radiation leaks and failed to give audiences a general indication of levels of risk. Second, the media over-emphasized the government's position that the environment was safe despite the more rampant word-of-mouth reports to the contrary, a slant that may have done nothing to allay public fear. Third, there was a dearth of information about what the government intends to do to alleviate the situation and suggestions about what people can do to protect themselves. The themes of news reports may be attributed to experts from research institutions and government officials who were the most frequently cited sources of facts, analyses, interpretations, and opinions. Scientists and nuclear experts were cited the most in the news reports. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2019

Necrotizing enterocolitis is preceded by increased gut bacterial replication, Klebsiella , and fimbriae-encoding bacteria

Necrotizing enterocolitis (NEC) is a devastating intestinal disease that occurs primarily in premature infants. We performed genome-resolved metagenomic analysis of 1163 fecal samples from premature infants to identify microbial features predictive of NEC. Features considered include genes, bacterial strain types, eukaryotes, bacteriophages, plasmids, and growth rates. A machine learning classifier found that samples collected before NEC diagnosis harbored significantly more Klebsiella , bacteria encoding fimbriae, and bacteria encoding secondary metabolite gene clusters related to quorum sensing and bacteriocin production. Notably, replication rates of all bacteria, especially Enterobacteriaceae, were significantly higher 2 days before NEC diagnosis. The findings uncover biomarkers that could lead to early detection of NEC and targets for microbiome-based therapeutics.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2012

Evaluation of a Genome-Scale In Silico Metabolic Model for Geobacter metallireducens Using Proteomic Data from a Field Biostimulation Experiment

Biomass and shotgun global proteomics data that reflected relative protein abundances from samples collected during the 2008 experiment at the U.S. Department of Energy Integrated Field-Scale Subsurface Research Challenge site in Rifle, Colorado, provided an unprecedented opportunity to validate a genome-scale metabolic model of Geobacter metallireducens and assess its performance with respect to prediction of metal reduction, biomass yield, and growth rate under dynamic field conditions. Reconstructed from annotated genomic sequence, biochemical, and physiological data, the constraint-based in silico model of G. metallireducens relates an annotated genome sequence to the physiological functions with 697 reactions controlled by 747 enzyme-coding genes. Proteomic analysis showed that 180 of the 637 G. metallireducens proteins detected during the 2008 experiment were associated with specific metabolic reactions in the in silico model. When the field-calibrated Fe(III) terminal electron acceptor process reaction in a reactive transport model for the field experiments was replaced with the genome-scale model, the model predicted that the largest metabolic fluxes through the in silico model reactions generally correspond to the highest abundances of proteins that catalyze those reactions. Central metabolism predicted by the model agrees well with protein abundance profiles inferred from proteomic analysis. Model discrepancies with the proteomic data, such as the relatively low fluxes through amino acid transport and metabolism, revealed pathways or flux constraints in the in silico model that could be updated to more accurately predict metabolic processes that occur in the subsurface environment.

Fang, Yilin↗
DOE OSTI2014

Identification and environmental distribution of dcpA encoding the 1,2-dichloropropane-to-propene reductive dehalogenase in organohalide-respiring Chloroflexi

Dehalococcoides mccartyi (Dhc) strains KS and RC grow with 1,2-dichloropropane (1,2-D) as an electron acceptor in enrichment cultures derived from hydrocarbon-contaminated and pristine river sediments, respectively. Transcription, expression, enzymatic and PCR analyses implicated the reductive dehalogenase gene dcpA in 1,2-D dichloroelimination to propene and inorganic chloride. Quantitative real-time PCR (qPCR) analyses demonstrated Dhc cell increase during growth with 1,2-D and suggested that both Dhc strains carried a single dcpA gene copy per genome. Dhc strain RC and strain KS produced 1.8 0.1 x 107 and 1.4 0.5 x 107 cells per mole of propene formed, respectively. The dcpA gene was identified in 1,2-D-to-propene-dechlorinating microcosms established with sediment samples collected from different geographical locations in Europe and North and South America. Clone library analysis revealed two distinct dcpA phylogenetic clusters, both of which the dcpA gene-targeted qPCR assay captured, suggesting the qPCR assay is useful for site assessment and bioremediation monitoring at 1,2-D-contaminated sites.

Padilla-Crespo, Elizabeth↗
DOE OSTI2013

The Draft Genome Sequence of Nocardioides sp. Strain CF8 Reveals the Scope of Its Metabolic Capabilities

Nocardioides sp. strain CF8 was isolated from a soil sample collected at the Hanford Department of Energy site, Richland, WA. The strain was identified in microcosms based on its ability to grow on butane and has been characterized for its potential applications in the biodegradation of halogenated hydrocarbons. Here, the draft genome sequence is reported.

59 BASIC BIOLOGICAL SCIENCES↗