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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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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Aggregated nanoparticles: Sample preparation and analysis by atom probe tomography

Atom probe tomography (APT) allows measurement of the three-dimensional structure and composition of materials, but specific sample preparation procedures are required for challenging materials such as aggregates of nanoparticles. Indeed, the presence of porosity within the specimen affects both the stability of the sample and the accuracy of the data. In this work, aggregates of nanoparticles were transferred onto a micromanipulator tip and embedded via electron-beam-assisted deposition of Pt. Successive FIB-millings and Pt-depositions are needed to create suitable APT tips. The 3D reconstruction reveals the presence of 15–20 nm nanoparticles, and massspectral analysis shows the absence of trace elements within the catalyst, thus serving as quality control for the synthesis of nanoparticles with specific compositions.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2020

Acid Erosion of Carbonate Fractures and Accessibility of Arsenic-Bearing Minerals: In Operando Synchrotron-Based Microfluidic Experiment

Underground flows of acidic fluids through fractured rock can create new porosity and increase accessibility to hazardous trace elements such as arsenic. In this study, we developed a custom microfluidic cell for an in operando synchrotron experiment using X-ray attenuation. The experiment mimics reactive fracture flow by passing an acidic fluid over a surface of mineralogically heterogeneous rock from the Eagle Ford shale. Over 48 h, calcite was preferentially dissolved, forming an altered layer 200–500 μm thick with a porosity of 63–68% and surface area >10$\times$ higher than that in the unreacted shale as shown by xCT analyses. Calcite dissolution rate quantified from the attenuation data was 3 $\times$ 10 –4 mol/m 2 s and decreased to 3 $\times$ 10 –5 mol/m 2 s after 24 h because of increasing diffusion limitations. Erosion of the fracture surface increased access to iron-rich minerals, thereby increasing access to toxic metals such as arsenic. Quantification using XRF and XANES microspectroscopy indicated up to 0.5 wt % of As(-I) in arsenopyrite and 1.2 wt % of As(V) associated with ferrihydrite. This study provides valuable contributions for understanding and predicting fracture alteration and changes to the mobilization potential of hazardous metals and metalloids.

58 GEOSCIENCES↗
DOE OSTI2022

Evaluation of Load Behavior for Select Analytes in Hanford Tank Waste

Crystalline silicotitanate (CST) inorganic ion exchanger is a candidate material for remediation of highly alkaline (pH > 14) aqueous nuclear waste streams containing high sodium concentrations (>5 M). In this work, ion exchange column testing with wastes from Hanford tanks AP-105, AP-107, and AW-102 was carried out to study the uptake of 137 Cs to estimate the decontamination factor (DF) value. Additionally, DF values for uptake of Al, Ca, Pb, Np, Pu, U, and Sr were determined and the ion exchange capacity of CST toward these analytes was estimated. Limited data is available on the load behavior of other minor and trace elements with recent CST production lots and this characterization will help improve understanding of the behavior of CST and assist in identifying potential disposition pathways as well as assessing removal capabilities of CST for other components.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Progress in Uranium Chemistry: Driving Advances in Front-End Nuclear Fuel Cycle Forensics

The front-end of the nuclear fuel cycle encompasses several chemical and physical processes used to acquire and prepare uranium for use in a nuclear reactor. These same processes can also be used for weapons or nefarious purposes, necessitating the need for technical means to help detect, investigate, and prevent the nefarious use of nuclear material and nuclear fuel cycle technology. Over the past decade, a significant research effort has investigated uranium compounds associated with the front-end of the nuclear fuel cycle, including uranium ore concentrates (UOCs), UF 4 , UF 6 , and UO 2 F 2 . These efforts have furthered uranium chemistry with an aim to expand and improve the field of nuclear forensics. Focus has been given to the morphology of various uranium compounds, trace elemental and chemical impurities in process samples of uranium compounds, the degradation of uranium compounds, particularly under environmental conditions, and the development of improved or new techniques for analysis of uranium compounds. Overall, this research effort has identified relevant chemical and physical characteristics of uranium compounds that can be used to help discern the origin, process history, and postproduction history for a sample of uranium material. This effort has also identified analytical techniques that could be brought to bear for nuclear forensics purposes. Continued research into these uranium compounds should yield additional relevant chemical and physical characteristics and analytical approaches to further advance front-end nuclear fuel cycle forensics capabilities.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Intrafibrillar Mineralized Collagen–Hydroxyapatite-Based Scaffolds for Bone Regeneration

As one of the major challenges in the field of tissue engineering, large skeletal defects have attracted wide attention from researchers. Collagen (Col) and hydroxyapatite (HA), the most abundant protein and the main component in natural bone, resp., are usually used as a biomimetic composite material in tissue engineering due to their excellent biocompatibility and biodegradability. In this study, novel intrafibrillar mineralized Col-HA-based scaffolds, constructed in either cellular or lamellar microstructures, were established through a biomimetic method to enhance the new bone-regenerating capability of tissue engineering scaffolds. Moreover, iron (Fe) and manganese (Mn), two of the essential trace elements in the body, were successfully incorporated into the lamellar scaffold to further improve the osteoinductivity of these biomaterials. It was found that the lamellar scaffolds demonstrated better osteogenic abilities compared to both inhouse and com. Col-HA-based cellular scaffolds in vitro and in vivo. Meanwhile, Fe/Mn incorporation further amplified the osteogenic promotion of the lamellar scaffolds. More importantly, a synergistic effect was obsd. in the Fe and Mn dual-element-incorporated lamellar scaffolds for both in vitro osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) and in vivo bone regeneration loaded with fresh bone marrow cells. Furthermore, this study provides a simple but practical strategy for the creation of functional scaffolds for bone regeneration.

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

Revisiting Selenium Interactions with Pyrite: From Adsorption to Coprecipitation

Interactions of selenium (Se), a trace element bio-essential at low concentrations but highly toxic at high concentrations, with the most abundant sulfide mineral in the Earth's crust, namely pyrite, was investigated over a wide range of time scales. At the nanosecond scale, selenate Se(VI)O 4 2– adsorption onto the net pyrite surface is shown by ab-initio computations to proceed via the formation of a chemical bond between an oxyanion oxygen atom and a surface Fe atom, weakening the other Se-O bonds and reducing Se atom oxidation state. At the hour-to-day scale, adsorption and coprecipitation of selenate Se(VI)O 4 2– and selenite, Se(IV)O 3 2– , were investigated through wet chemical batch experiments at various pH values at different sulfide concentrations. Selenium removal from solution is slower and weaker for selenate than for selenite. After 24h, only 10% of selenate, against 60% of selenite (up to 100% in the presence of sulfide), is removed by the pyrite surface. Independently of its original oxidation state, adsorbed Se is completely reduced to elemental trigonal selenium via adsorption, precipitation or coprecipitation, as shown by XANES spectroscopy. Here, our EXAFS results, compared to published data on Se-rich pyrite, show a Se to S substitution within the pyrite structure. The reductive coprecipitation mechanism of selenium with pyrite represents valuable new insights for improving our understanding of modern and ancient biogeochemical cycles involving Se. In addition, several industries can benefit from direct applications of our findings, such as water treatment, green technologies and sustainable mining.

Adsorption↗
DOE OSTI2025

Mine Tailings Valorization by Electrochemically Stimulated Mineralization from Mildly Acidic Conditions

This study presents a high-efficiency electrochemical process for the mineralization of calcium carbonate (CaCO 3 ) from mildly acidic mine tailing supernatant water. Electrochemical pH control was used to promote carbonate speciation and precipitation from CO 2 -saturated solutions, achieving >1 mol CaCO 3 precipitated per mol e - at applied potentials between -1.4 and -1.6 V vs Ag/AgCl. Product morphology and polymorph selectivity were tunable via applied potential, yielding calcite and vaterite phases. Experiments using real mine tailings water confirmed selective calcite precipitation, despite the presence of sulfate and other trace elements. These results highlight a viable route for coupling CO 2 utilization with mine tailings valorization.

36 MATERIALS SCIENCE↗
DOE OSTI2026

A Three-Component Strategy for Synthesizing High-Entropy Alloy Nanoparticles with High-Index Facets

Controlling the shapes and, more importantly, exposed facets (high-index facets (HIFs), especially) of high-entropy alloy (HEA) nanoparticles is not yet possible. Herein, a three-component synthetic strategy for obtaining tetrahexahedral (THH)-shaped HIF-HEA nanoparticles through a combined alloying-dealloying strategy and liquid-metal mediation process is reported. Metal precursors are first alloyed with Ga to form multielemental nanoparticles and then alloyed with a volatile metal. Selectively dealloying the volatile metal from the nanoparticles is used to regulate their surface energies; the Ga stabilizes the HEA phase, and the trace element stabilizes the HIFs, resulting in THH-shaped HEA nanoparticles (seven different types) with {210} HIFs. Finally, nanoparticle megalibraries containing millions of THH-shaped HIF-HEAs on 4 cm 2 chips with size and composition control shows generalizability and scalability for materials discovery purposes.

alloys↗
DOE OSTI2020

Iron Speciation in PM 2.5 From Urban, Agriculture, and Mixed Environments in Colorado, USA

Atmospheric iron solubility varies depending on whether the particles are collected in rural or urban areas, with urban areas showing increased iron solubility. In this study, we investigate if the iron species present in different environments affects its ultimate solubility. Field data are presented from the Platte River Air Pollution and Photochemistry Experiment (PRAPPE), aimed at understanding the interactions between organic carbon and trace elements in atmospheric particulate matter (PM). 24-hr PM 2.5 samples were collected during the summer and winter (2016–2017), at three different sites on the Eastern Colorado plains: an urban, agricultural, and a mixed site. Downtown Denver had an average total and water-soluble iron air concentration of 181.2 and 7.7 ng m -3 , respectively. Platteville, the mixed site, had an average of total iron of 76.1 ng m -3 , with average water-soluble iron concentration of 9.1 ng m -3 . Jackson State Park (rural/agricultural) had the lowest total iron average of 31.5 ng m -3 and the lowest water-soluble iron average, 1.3 ng m -3 . The iron oxidation state and chemical speciation of 97 samples across all sites and seasons was probed by X-ray absorption near edge structure (XANES) spectroscopy. The most common iron phases observed were almandine (Fe 3 Al 2 Si 3 O 12 ) (Denver 21%, Platteville 16%, Jackson 24%), magnetite (Fe 3 O 4 ) (Denver 9%, Platteville 4%, Jackson 5%) and Fe (III)dextran (Denver 5%, Platteville 13%, Jackson 5%), a surrogate for Fe-organic complexes. Additionally, native iron [Fe(0)] was found in significant amounts at all sites. No correlation was observed between iron solubility and iron oxidation state or chemical speciation.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2025

Eocene-Oligocene Metamorphism, Fluid Flow and Deformation in the Ruby Mountains-East Humboldt Range Metamorphic Core Complex

Metamorphic core complexes are ubiquitous in collapsed orogens globally and play a primary role in crustal exhumation. Here, we investigate the metamorphic history of the Ruby Mountains-East Humboldt Range metamorphic core complex, Nevada, using petrochronology to understand how magmatism, metamorphism and deformation interact to modulate crustal rheology, and the timing of exhumation within the Sevier orogenic belt. Field study, microstructural analysis, thermobarometry and laser ablation split-stream monazite, titanite and allanite petrochronology of the mylonitic footwall were integrated to elucidate the pressure-temperature-time (P-T-t) evolution. Major-, trace-element and quartz-in-garnet thermobarometry show peak metamorphism occurred at 5.5–6 kbar and 600–650°C across the study area. Monazite and titanite U-(Th)-Pb petrochronology constrain this episode of metamorphism to 88–81 Ma with the structurally deepest samples yielding dates down to ca. 71 Ma. The preservation of peak metamorphic mineral assemblages indicates these rocks remained at near-peak temperature conditions into the Cenozoic. Cenozoic metamorphism occurred during a punctuated episode contemporaneous with the Great Basin ignimbrite flare up. All samples show a distinct 39–37 Ma population of monazite, titanite and allanite dates that correlate with the emplacement of quartz diorite and gabbro intrusions throughout the footwall. Accessory phases contain zoning textures in backscattered electron images that are consistent with fluid-mediated dissolution-reprecipitation reactions. The U-(Th)-Pb analyses from these zones yield 39–27 Ma dates interpreted as the timing of fluid flow. The results of this study elucidate the integrated importance of magmatism, melting and fluid flow in driving the coupled evolution of Late Cretaceous metamorphism within the Sevier hinterland and the subsequent Cenozoic metamorphic core complex development that exhumed the middle crust.

58 GEOSCIENCES↗
DOE OSTI2021

A new hypothesis for the origin of Amazonian Dark Earths

Amazonian Dark Earths (ADEs) are unusually fertile soils characterised by elevated concentrations of microscopic charcoal particles, which confer their distinctive colouration. Frequent occurrences of pre-Columbian artefacts at ADE sites led to their ubiquitous classification as Anthrosols (soils of anthropic origin). However, it remains unclear how indigenous peoples created areas of high fertility in one of the most nutrient-impoverished environments on Earth. Here, we report new data from a well-studied ADE site in the Brazilian Amazon, which compel us to reconsider its anthropic origin. The amounts of phosphorus and calcium—two of the least abundant macronutrients in the region—are orders of magnitude higher in ADE profiles than in the surrounding soil. The elevated levels of phosphorus and calcium, which are often interpreted as evidence of human activity at other sites, correlate spatially with trace elements that indicate exogenous mineral sources rather than in situ deposition. Stable isotope ratios of neodymium, strontium, and radiocarbon activity of microcharcoal particles also indicate exogenous inputs from alluvial deposition of carbon and mineral elements to ADE profiles, beginning several thousands of years before the earliest evidence of soil management for plant cultivation in the region. Our data suggest that indigenous peoples harnessed natural processes of landscape formation, which led to the unique properties of ADEs, but were not responsible for their genesis. If corroborated elsewhere, this hypothesis would transform our understanding of human influence in Amazonia, opening new frontiers for the sustainable use of tropical landscapes going forward.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2023

River thorium concentrations can record bedrock fracture processes including some triggered by distant seismic events

Fractures are integral to the hydrology and geochemistry of watersheds, but our understanding of fracture dynamics is very limited because of the challenge of monitoring the subsurface. Here we provide evidence that long-term, high-frequency measurements of the river concentration of the ultra-trace element thorium (Th) can provide a signature of bedrock fracture processes spanning neighboring watersheds in Colorado. River Th concentrations show abrupt (subdaily) excursions and biexponential decay with approximately 1-day and 1-week time constants, concentration patterns that are distinct from all other solutes except beryllium and arsenic. The patterns are uncorrelated with daily precipitation records or seasonal trends in atmospheric deposition. Groundwater Th analyses are consistent with bedrock release and dilution upon mixing with river water. Most Th excursions have no seismic signatures that are detectable 50 km from the site, suggesting the Th concentrations can reveal aseismic fracture or fault events. We find, however, a weak statistical correlation between Th and seismic motion caused by distant earthquakes, possibly the first chemical signature of dynamic earthquake triggering, a phenomenon previously identified only through geophysical methods.

58 GEOSCIENCES↗
DOE OSTI2020

Nucleation and growth of voids in shock loaded copper bicrystals

Understanding the evolution of damage and deformation due to spall at grain boundaries can provide a basis for connecting micro- to macroscale failure behavior in metals under extreme conditions. Copper bicrystal samples were shock loaded using flyer-plate impacts in a light gas gun with shock stresses ranging from 3 to 6 GPa. Pulse duration as well as crystal orientation along the shock direction were varied for a fixed boundary misorientation to determine their effects on void nucleation and coalescence. Samples were soft recovered and cross-sectioned to characterize damage using electron backscattering diffraction and scanning electron microscopy to gather information on damage characteristics at and around the GB, with emphasis on growth of boundary and bulk voids. Chemistry and composition analysis were also performed on samples to determine if trace elements present in a sample affected the threshold for void nucleation. Results show that the kinetics of damage growth at the boundary are strongly affected by stress level and impurities. It was found that the boundary selected had a similar or even lower tendency to show damage than the bulk at low pulse durations and amplitudes. As pulse duration and amplitude increased damage localized at the boundary, which was found to consist of many small voids, indicating that the boundary experienced rapid void nucleation and coalescence. Furthermore, the presence of impurities correlated strongly with scatter on damage evolution.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Using cyclotron radiation emission for ultra-high resolution x-ray spectroscopy

Abstract Cyclotron radiation emission spectroscopy (CRES) is an approach to measuring the energy of an electron trapped in an externally applied magnetic field. The bare electron can come from different interactions, including photoelectric absorption, Compton scatters, beta decay, and pair production. CRES relies on measuring the frequency of the electron’s cyclotron motion, and because the measurement times extend over 10 6 –10 7 cycles, the energy resolution is on the order of a single electronvolt. To date, CRES has only been performed on internal beta-emitting radioisotopes, but the technology can be applied to x-ray spectrometery through appropriate selection of a target gas and sufficient intensity of the distinct x-ray source. The applications of this technology range from high-precision measurements of atomic energy levels to calibrations of basic science experiments, to trace element identification. In this work we explore the use of CRES for x-ray spectroscopy within the rubric of measuring the energy levels of argon. Though the energy levels of argon are well established, we adopt this motivation as an example question around which a detector may be designed. The issues we explore include target material, density, electron trapping depth, noise levels, and overall efficiency. We also discuss spectral deconvolution and how the multiple peaks obtained from a single target/source pair can be used to enhance the robustness of the measurement.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2020

Supplemental selenium source on gut health: insights on fecal microbiome and fermentation products of growing puppies

ABSTRACT Selenium is an essential trace element that can modulate the gut microbiome with an impact on host health. The present study aimed to evaluate the effects of organic (selenium-enriched yeast) vs inorganic (sodium selenite) selenium source on fecal end-fermentation products and gut microbiome of puppies from 20 to 52 weeks of age. Alpha and beta diversity of the gut bacterial community were affected by age but not by gender or selenium source. The relative abundance of taxa was differently affected by age, and the DNA concentration of all selected bacterial groups increased with age, although total volatile fatty acids (VFA), acetate, propionate, caproate and lactate concentrations decreased. Organic selenium was associated with a higher concentration of total VFA, propionate and butyrate, a higher number of DNA copies of Lactobacillus, and a trend to lower DNA copies of Escherichia coli. Effects on fecal microbiome during growth differed with selenium source. Females had higher fecal end-fermentation products related to protein degradation, whereas males had higher DNA concentration of Bifidobacterium. Organic selenium might be beneficial over inorganic for dog food supplementation due to the positive modulation of the gut microbiome observed in puppies.

Pereira, Ana Margarida↗
DOE OSTI2022

X-ray fluorescence microscopy methods for biological tissues

Abstract Synchrotron-based X-ray fluorescence microscopy is a flexible tool for identifying the distribution of trace elements in biological specimens across a broad range of sample sizes. The technique is not particularly limited by sample type and can be performed on ancient fossils, fixed or fresh tissue specimens, and in some cases even live tissue and live cells can be studied. The technique can also be expanded to provide chemical specificity to elemental maps, either at individual points of interest in a map or across a large field of view. While virtually any sample type can be characterized with X-ray fluorescence microscopy, common biological sample preparation methods (often borrowed from other fields, such as histology) can lead to unforeseen pitfalls, resulting in altered element distributions and concentrations. A general overview of sample preparation and data-acquisition methods for X-ray fluorescence microscopy is presented, along with outlining the general approach for applying this technique to a new field of investigation for prospective new users. Considerations for improving data acquisition and quality are reviewed as well as the effects of sample preparation, with a particular focus on soft tissues. The effects of common sample pretreatment steps as well as the underlying factors that govern which, and to what extent, specific elements are likely to be altered are reviewed along with common artifacts observed in X-ray fluorescence microscopy data.

Pushie, M. Jake (ORCID:0000000174945427)↗
DOE OSTI2022

ROI-Finder : machine learning to guide region-of-interest scanning for X-ray fluorescence microscopy

The microscopy research at the Bionanoprobe (currently at beamline 9-ID and later 2-ID after APS-U) of Argonne National Laboratory focuses on applying synchrotron X-ray fluorescence (XRF) techniques to obtain trace elemental mappings of cryogenic biological samples to gain insights about their role in critical biological activities. The elemental mappings and the morphological aspects of the biological samples, in this instance, the bacterium Escherichia coli ( E. Coli ), also serve as label-free biological fingerprints to identify E. coli cells that have been treated differently. The key limitations of achieving good identification performance are the extraction of cells from raw XRF measurements via binary conversion, definition of features, noise floor and proportion of cells treated differently in the measurement. Automating cell extraction from raw XRF measurements across different types of chemical treatment and the implementation of machine-learning models to distinguish cells from the background and their differing treatments are described. Principal components are calculated from domain knowledge specific features and clustered to distinguish healthy and poisoned cells from the background without manual annotation. The cells are ranked via fuzzy clustering to recommend regions of interest for automated experimentation. The effects of dwell time and the amount of data required on the usability of the software are also discussed.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2020

The fall, recovery, classification, and initial characterization of the Hamburg, Michigan H4 chondrite

Abstract The Hamburg meteorite fell on January 16, 2018, near Hamburg, Michigan, after a fireball event widely observed in the U.S. Midwest and in Ontario, Canada. Several fragments fell onto frozen surfaces of lakes and, thanks to weather radar data, were recovered days after the fall. The studied rock fragments show no or little signs of terrestrial weathering. Here, we present the initial results from an international consortium study to describe the fall, characterize the meteorite, and probe the collision history of Hamburg. About 1 kg of recovered meteorites was initially reported. Petrology, mineral chemistry, trace element and organic chemistry, and O and Cr isotopic compositions are characteristic of H4 chondrites. Cosmic ray exposure ages based on cosmogenic 3 He, 21 Ne, and 38 Ar are ~12 Ma, and roughly agree with each other. Noble gas data as well as the cosmogenic 10 Be concentration point to a small 40–60 cm diameter meteoroid. An 40 Ar‐ 39 Ar age of 4532 ± 24 Ma indicates no major impact event occurring later in its evolutionary history, consistent with data of other H4 chondrites. Microanalyses of phosphates with LA‐ICPMS give an average Pb‐Pb age of 4549 ± 36 Ma. This is in good agreement with the average SIMS Pb‐Pb phosphate age of 4535.3 ± 9.5 Ma and U‐Pb Concordia age of 4535 ± 10 Ma. The weighted average age of 4541.6 ± 9.5 Ma reflects the metamorphic phosphate crystallization age after parent body formation in the early solar system.

79 ASTRONOMY AND ASTROPHYSICS↗