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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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Coordination environment of Si in calcium silicate hydrates, silicate minerals, and blast furnace slags: A XANES database

Understanding the silicate polymerization of calcium silicate hydrate (C-S-H) gel and its crystalline polymorphs is important in cement science. NMR can determine Si environments, but the measurement can be time-consuming and provides no spatial information. X-ray absorption near-edge structure (XANES) spectroscopy is a fast tool for probing Si coordination, possibly with spatial information. However, there lacks an understanding of Si K-edge XANES spectra of cement-related silicate phases. Here, a Si K-edge XANES spectral database of nanocrystalline C-S-H, C-S-H minerals, blast-furnace slags, and metakaolin is provided. Si K-edge of C-S-H minerals shifts to higher energies with higher polymerized Si and lower CaSi connectivity in the Si second nearest neighbor shell. Si K-edge energy shows weak correlations with Ca/Si ratio, average SiO bond length, and SiO{sub 4} distortion due to the structural complexity of silicates. The substitution of Al for Si shifts the Si K-edge of tobermorite and slags to higher energies.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Si-based materials for lithium-ion batteries XI. 70% surface-modified Si/C/perfluorooctene-carbon black/lithiated polyacrylic acid electrode

X-ray photoelectron spectroscopy was used to analyze a 70% Si/C/perfluorooctene-carbon black/lithiated polyacrylic acid electrode fabricated at the Cell Analysis, Modeling, and Prototyping (CAMP) Facility, Argonne National Laboratory. The spectra were obtained using incident monochromatic Al K α radiation at 1486.6 eV (0.83 401 nm). A survey spectrum together with O 1s, C 1s, and Si 2p are presented. The spectra indicate the principal core level photoelectron and Auger electron signals with only minor sodium, copper, calcium, and lithium signals and show the expected silicon-carbon, carbon-fluorine, and silicon-fluorine species related to the surface modification process in addition to oxidized carbon and silicon due to atmospheric exposure.

25 ENERGY STORAGE↗
DOE OSTI2021

Hydrogenous Content in Residues from Aqueous Chloride Pu and Am Recovery Operations

Byproduct residues generated from Aqueous Chloride Pu and Am recovery operations at Los Alamos National Laboratory have been investigated and determined to contain high weight % chloride salts and minimal hydrogen content. Hydrogen content is the result of limited surface area adsorption of ambient moisture. The assumption used in technical analysis NCS-TECH-19-029 to model potentially hydrogenous items as mixtures of polyethylene is shown to be overly conservative. Our results and literature precedent indicate that water adsorption of 1-3 % by weight is expected for hydroxide cakes and Pu oxides, and a conservative bounding assumption for these materials is 5% water by weight. LOH results for a dissolution heel stored long term showed 6.25% weight loss, which was conservatively assumed to be water. A conservative bounding assumption for dissolution heels is 8 wt.% water content. This equates to 0.55 % hydrogen by weight for hydroxide cakes, and 0.88% hydrogen by weight for dissolution heels. The bulk composition of dissolution heels reflects the composition of the original byproduct feed material, chloride salts of potassium, sodium, magnesium and calcium. The bulk composition of calcined hydroxide precipitation residues is composed of potassium chloride as a result of potassium hydroxide neutralization of hydrochloric acid solutions. Metal hydroxides generated during the hydroxide precipitation process are decomposed under the conditions of calcination to metal oxide forms.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2021

Calcium-Ion Binding Mediates the Reversible Interconversion of Cis and Trans Peroxido Dicopper Cores

Coupled dinuclear copper oxygen cores (Cu 2 O 2 ) featured in type III copper proteins (hemocyanin, tyrosinase, catechol oxidase) are vital for O 2 transport and substrate oxidation in many organisms. μ-1,2-cis peroxido dicopper cores ( C P) have been proposed as key structures in the early stages of O 2 binding in these proteins; their reversible isomerization to other Cu 2 O 2 cores are directly relevant to enzyme function. Furthermore, despite the relevance of such species to type III copper proteins and the broader interest in the properties and reactivity of bimetallic C P cores in biological and synthetic systems, the properties and reactivity of C P Cu 2 O 2 species remain largely unexplored. Herein, we report the reversible interconversion of μ-1,2-trans peroxido ( T P) and C P dicopper cores. Ca II mediates this process by reversible binding at the Cu 2 O 2 core, highlighting the unique capability for metal-ion binding events to stabilize novel reactive fragments and control O 2 activation in biomimetic systems.

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

Electro-assisted regeneration of pH-sensitive ion exchangers for sustainable phosphate removal and recovery

Removal and recovery of phosphate from wastewater can minimize deleterious environmental impacts and supplement fertilizer supply. Hybrid anion exchangers (HAIX, with doped ferric oxide nanoparticles (FeOnp)) can remove phosphate from complex wastewaters and recover concentrated phosphate solutions. Here, we integrate HAIX with a weak acid cation exchanger (WAC) to enrich phosphate and calcium in mild regenerants and precipitate both elements for recovery. We demonstrated an electro-assisted regeneration approach to avoid strong acid and base input. Based on demonstrated pH sensitivities of both materials, electrochemically produced mild electrolytes (pH 3 and pH 11), which are 100–1000 times less concentrated than typical regenerants, preserved 80% WAC and 50% HAIX capacities over five batch adsorption-regeneration cycles. FeOnp in HAIX facilitated regeneration due to pH sensitivity and their likely distribution on the resin particle surface, which reduced intraparticle diffusion path length. In column tests, repeatable phosphate removal (> 95%) from synthetic wastewater (3 mg P/L) was achieved with 20 kWh/kg P specific energy consumption. After removal, a similar 50% HAIX regeneration efficiency as batch experiments was achieved. In spent regenerant, more than 95% phosphorus was recovered as hydroxyapatite. This novel approach enhances ion exchange by minimizing chemical inputs.

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

Calcium‐Ion Binding Mediates the Reversible Interconversion of Cis and Trans Peroxido Dicopper Cores

Abstract Coupled dinuclear copper oxygen cores (Cu 2 O 2 ) featured in type III copper proteins (hemocyanin, tyrosinase, catechol oxidase) are vital for O 2 transport and substrate oxidation in many organisms. μ ‐1,2‐ cis peroxido dicopper cores ( C P ) have been proposed as key structures in the early stages of O 2 binding in these proteins; their reversible isomerization to other Cu 2 O 2 cores are directly relevant to enzyme function. Despite the relevance of such species to type III copper proteins and the broader interest in the properties and reactivity of bimetallic C P cores in biological and synthetic systems, the properties and reactivity of C P Cu 2 O 2 species remain largely unexplored. Herein, we report the reversible interconversion of μ ‐1,2‐ trans peroxido ( T P ) and C P dicopper cores. Ca II mediates this process by reversible binding at the Cu 2 O 2 core, highlighting the unique capability for metal‐ion binding events to stabilize novel reactive fragments and control O 2 activation in biomimetic systems.

Vargo, Natasha P.↗
DOE OSTI2025

Joint Theoretical and Experimental Study of the Electronic, Magnetic, and Lattice Phonon Dynamics Properties of Ca x Fe y O z Compounds Applied to CO 2 Capture

Unleashing energy innovation ensures a resilient and reliable energy supply. There is a critical need for the development of new carbon dioxide (CO 2 ) captors that have improved energy efficiency accompanied by lower capital and operational costs to ensure abundant, affordable, and secure energy. Among solid materials, CaO is a good CO 2 sorbent for capture technology due to its wide availability and low cost. However, CaO also suffers from some disadvantages, such as high calcination temperature, decreasing capability due to sintering, attrition, and reaction with SO x and NO x . In this study, we employed an ab initio thermodynamic approach and experimental measurements to improve its CO 2 capture performance during the cycles. To do so, we explored the electronic, magnetic, and lattice dynamic properties of a series of calcium ferrites (Ca x Fe y O z ) and applied them for CO 2 capture. Our results showed that all of them can thermodynamically react with CO 2 to form CaCO 3 and iron oxides. Compared to pure CaO capturing CO 2 , CaFe 3 O 4 , CaFe 2 O 4 , and Ca 2 Fe 2 O 5 could shift the CO 2 regeneration temperature to a lower range. The experimental measurements showed that CaFeO 2 is a good CO 2 captor with or without the presence of an O 2 presence. The calculated thermodynamic properties of Ca x Fe y O z capturing the CO 2 reactions can be used to find their operational temperature ranges for different CO 2 capture technologies.

CO2 capture↗
DOE OSTI2024

Investigating sol–gel matrix loading capacity toward producing surrogate nuclear explosive debris with realistic composition

Post detonation nuclear forensic materials which resemble the size, color, elemental composition, and radionuclide content of real nuclear debris would be valuable for developing and validating new nuclear forensic techniques. As nuclear fallout types vary significantly, the ability to tailor each of these parameters accurately is desired to produce materials capable of testing analytical methods under a wide array of forensic scenarios. Sol–gel synthesis techniques can provide tunability of size, shape and composition for producing a wide variety of solid nuclear forensics benchmarking materials. Further, the sol–gel process consists of forming a metal oxide material, often silica, through polymerization of a metal-alkoxy precursor. In this work, we characterize the ability to load sol–gel particles with secondary elemental components such as iron, aluminum, and calcium toward producing benchmarking materials approximating the elemental composition of historic nuclear debris from the Nevada National Security Site. We also demonstrate quantitative radionuclide encapsulation toward producing benchmarking materials with controllable radionuclide content. Finally, we employ these techniques to produce nuclear debris benchmarking materials with controllable elemental matrix composition and radionuclide content and compare these samples with the composition of a historic fallout sample previously reported from the Nevada National Security Site.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Investigation of Ca Insertion into α-MoO 3 Nanoparticles for High Capacity Ca-Ion Cathodes

Calcium-ion batteries (CIBs) are a promising alternative to lithium-ion batteries (LIBs) due to the low redox potential of calcium metal and high abundance of calcium compounds. Due to its layered structure, α-MoO 3 is regarded as a promising cathode host lattice. While studies have reported that α-MoO 3 can reversibly intercalate Ca ions, limited electrochemical activity has been noted, and its reaction mechanism remains unclear. Here, we re-examine Ca insertion into α-MoO 3 nanoparticles with a goal to improve reaction kinetics and clarify the storage mechanism. The α-MoO 3 electrodes demonstrated a specific capacity of 165 mA h g –1 centered near 2.7 V vs Ca 2+ /Ca, stable long-term cycling, and good rate performance at room temperature. Furthermore, this work demonstrates that, under the correct conditions, layered oxides can be a promising host material for CIBs and renews prospects for CIBs.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Susceptibility of pESI positive Salmonella to treatment with biocide chemicals approved for use in poultry meat processing as compared to Salmonella without the pESI plasmid

Abstract Salmonella is a common cause of human foodborne illness, which is frequently associated with consumption of contaminated or undercooked poultry meat. Serotype Infantis is among the most common serotypes isolated from poultry meat products globally. Isolates of serotype Infantis carrying the pESI plasmid, the most dominant strain of Infantis, have been shown to exhibit oxidizer tolerance. Therefore, 16 strains of Salmonella with and without pESI carriage were investigated for susceptibility to biocide chemical processing aids approved for use in US poultry meat processing: peracetic acid (PAA), cetylpyridinium chloride (CPC), calcium hypochlorite, and sodium hypochlorite. Strains were exposed for 15 s to simulate spray application and 90 min to simulate application in an immersion chiller. All strains tested were susceptible to all concentrations of PAA, CPC, and sodium hypochlorite when applied for 90 min. When CPC, calcium hypochlorite, and sodium hypochlorite were applied for 15 s to simulate spray time, strains responded similarly to each other. However, strains responded variably to exposure to PAA. The variation was not statistically significant and appears unrelated to pESI carriage. Results highlight the necessity of testing biocide susceptibility in the presence of organic material and in relevant in situ applications.

Biotechnology & Applied Microbiology↗
DOE OSTI2022

Stable Element Doping of Sol-gel Toward Simulating Environmental Matrix in Surrogate Explosive Nuclear Debris

Training nuclear forensic analysis personnel in post-detonation scenarios is of critical importance to nuclear threat response capabilities. Thus, realistic nuclear debris simulants which resemble the size, color, elemental composition, and radionuclide content of actual nuclear fallout from a recent detonation would be valuable for training nuclear first responders in realistic scenarios. As nuclear fallout types vary significantly in each of these parameters based on detonation environment (rural, urban, maritime etc.) and collection location, the ability to tailor each of these parameters accurately in simulated debris would be of immense benefit to the post-detonation analysis community for training both in-field collections and triage and the validation of laboratory level nuclear forensic techniques. Sol-gel synthesis techniques can provide the tunability of size, shape and composition required for producing surrogate nuclear debris of a wide variety. The sol-gel process consists of forming a metal oxide material, often silica, through polymerization of a metal-alkoxy precursor. In this work, we characterize the ability to load the sol-gel particles with secondary elemental components such as iron, aluminum, and calcium toward approximating the elemental composition of debris from various detonation environments and demonstrate the ability to produce particles with controllable size, shape, and color. We also demonstrate quantitative radionuclide encapsulation toward reproducing the radionuclide content of actual fallout from a recent detonation. Finally, we then employ these techniques in producing simulated aerodynamic debris samples with realistic elemental matrix composition and radionuclide content simulating a recent uranium-fueled detonation taking place in a rural desert environment and compare it to historic fallout from the Nevada Nuclear Security Site.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Stable Element Doping of Sol-gel Toward Simulating Environmental Matrix in Surrogate Explosive Nuclear Debris

Training nuclear forensic analysis personnel in post-detonation scenarios is of critical importance to nuclear threat response capabilities. Thus, realistic nuclear debris simulants which resemble the size, color, elemental composition, and radionuclide content of actual nuclear fallout from a recent detonation would be valuable for training nuclear first responders in realistic scenarios. As nuclear fallout types vary significantly in each of these parameters based on detonation environment (rural, urban, maritime etc.) and collection location, the ability to tailor each of these parameters accurately in simulated debris would be of immense benefit to the post-detonation analysis community for training both in-field collections and triage and the validation of laboratory level nuclear forensic techniques. Sol-gel synthesis techniques can provide the tunability of size, shape and composition required for producing surrogate nuclear debris of a wide variety. The sol-gel process consists of forming a metal oxide material, often silica, through polymerization of a metal-alkoxy precursor. In this work, we characterize the ability to load the sol-gel particles with secondary elemental components such as iron, aluminum, and calcium toward approximating the elemental composition of debris from various detonation environments and demonstrate the ability to produce particles with controllable size, shape, and color. We also demonstrate quantitative radionuclide encapsulation toward reproducing the radionuclide content of actual fallout from a recent detonation. Finally, we then employ these techniques in producing simulated aerodynamic debris samples with realistic elemental matrix composition and radionuclide content simulating a recent uranium-fueled detonation taking place in a rural desert environment and compare it to historic fallout from the Nevada Nuclear Security Site.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Nanostructured mixed metal oxides as catalysts and method of making thereof

A method of forming a metal oxide material having a rod shape or polyhedral nanostructure includes preparing a first reverse micro-emulsion system comprising an aqueous precipitating agent dispersion and a second reverse micro-emulsion system containing an aqueous metal salt dispersion; combining the micro-emulsions together to initiate a reaction; allowing the reaction to continue to form a product mixture comprising a metal oxide gel and aqueous media; separating the metal oxide gel from the aqueous media; collecting the metal oxide gel; and calcining the metal oxide gel to form the metal oxide material. The metal oxide material corresponds to the chemical formula of La2MxNi1-xO4, Pr2-yAyNiO4, or La2-zDzNiO4, wherein M is copper, cobalt, iron, manganese, chromium, aluminum, or platinum; A is lanthanum or neodymium; D is calcium, barium or strontium; x ranges from 0 to 1; y ranges from 0 to 2; and z ranges from 0 to 0.25.

Nikolla, Eranda↗
DOE OSTI2021

Immobilization of active ammonia-oxidizing archaea in hydrogel beads

Abstract Ammonia-oxidizing archaea (AOA) are major players in the nitrogen cycle but their cultivation represents a major challenge due to their slow growth rate and limited tendency to form biofilms. In this study, AOA was embedded in small (~2.5 mm) and large (~4.7 mm) poly(vinyl alcohol) (PVA)—sodium alginate (SA) hydrogel beads cross-linked with four agents (calcium, barium, light, or sulfate) to compare the differences in activity, the diffusivity of nitrogen species (NH 4 + , NO 2 − , and NO 3 − ), and polymer leakage in batch systems over time. Sulfate-bound PVA-SA beads were the most stable, releasing the lowest amount of polymer without shrinking. Diffusion coefficients were found to be 2 to 3 times higher in hydrogels than in granules, with ammonium diffusivity being ca . 35% greater than nitrite and nitrate. Despite a longer lag phase in small beads, embedded AOA sustained a high per volume rate of ammonia oxidation compatible with applications in research and wastewater treatment.

42 ENGINEERING↗
DOE OSTI2021

DPC Cement Filler Development (Progress Report)

The fillers research and development (R&D) program, mostly experimental, is part of a broader R&D program that includes new process modeling and performance assessment of criticality effects and the overall importance of criticality to repository performance (consequence screening). A literature research and consultation effort with experts by Hardin and Brady (2018) identified several potentially effective and workable filler materials including cements (primarily phosphate based), moltenmetal alloys, and low-temperature glasses. Filler attributes were defined, and the preliminary lists were compared qualitatively. Further comparative analysis will be done (e.g., cost estimates) after experimental screening has narrowed the list of alternatives. The following cement filler compositions were selected for experimental development work and accelerated testing in FY20: Aluminum phosphate cements (APCs); more specifically aluminum oxide / aluminum phosphate (Al 2 O 3 / AlPO 4 ) cements in which Al 2 O 3 serves as the filler material bound by an AlPO 4 binder formed by the reaction of Al 2 O 3 with H 3 PO 4 ; Calcium phosphate cements (CPCs); more specifically composed of pure or nearly pure hydroxyapatite or HAP (Ca 5 (PO 4 ) 3 (OH)); Wollastonite phosphate cements (WPC), specifically wollastonite and aluminum or calcium aluminum phosphates in which CaSiO 3 serves as the filler material and the phosphate serves as the binder. The FY20 effort focused on the optimization of compositions and subsequent processing of these three materials to achieve dense and well-consolidated monolithic samples with 30 to 40% porosity and permeabilities of 1 millidarcy. At the close of this progress report the aluminum phosphate cements (APCs) and the wollastonite phosphate cements (WPCs) appear to show the most promise for continued development. Less progress has been made with the calcium phosphate cements (CPCs); their slurry viscosities are high (and difficult to measure) and they exhibit relatively short cure times of 2 to 3 hours with concomitant and excessive volatile (e.g. CO 2 ) generation.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Upcycling of Waste Plastics into Carboxylic Acids for Biodegradable Surfactants

This work outlines a process for producing high‐purity (>95%) carboxylate surfactants from post‐consumer recycled high‐density polyethylene (PCR‐HDPE). The approach involves the thermal depolymerization of PCR‐HDPE via pyrolysis, followed by fractional distillation to isolate C9–C14 olefins. These olefins undergo hydroformylation using cobalt carbonyl catalysts to generate aldehydes, which are subsequently oxidized to carboxylic acids using Pinnick oxidation under mild aqueous‐phase conditions. Neutralization of the resulting carboxylic acids with sodium hydroxide produces plastic‐derived carboxylate surfactants (PDCs) in the form of sodium carboxylates. Subsequent purification steps ensure surfactant‐grade purity and enable accurate assessment of physicochemical properties. The resulting PDCs are evaluated for critical micelle concentration (CMC), foamability, surface tension reduction, and calcium ion tolerance, demonstrating competitive behavior with conventional anionic carboxylate surfactants. This route provides a sustainable alternative for surfactant production, reducing reliance on fossil‐derived feedstocks and valorizing plastic waste streams through chemical upcycling.

Biodegradable surfactants↗
DOE OSTI2025

Probing substrate water access through the O1 channel of Photosystem II by single site mutations and membrane inlet mass spectrometry

Abstract Light-driven water oxidation by photosystem II sustains life on Earth by providing the electrons and protons for the reduction of CO 2 to carbohydrates and the molecular oxygen we breathe. The inorganic core of the oxygen evolving complex is made of the earth-abundant elements manganese, calcium and oxygen (Mn 4 CaO 5 cluster), and is situated in a binding pocket that is connected to the aqueous surrounding via water-filled channels that allow water intake and proton egress. Recent serial crystallography and infrared spectroscopy studies performed with PSII isolated fromThermosynechococcus vestitus(T. vestitus) support that one of these channels, the O1 channel, facilitates water access to the Mn 4 CaO 5 cluster during its S 2 →S 3 and S 3 →S 4 →S 0 state transitions, while a subsequent CryoEM study concluded that this channel is blocked in the cyanobacteriumSynechocystis sp.PCC 6803, questioning the role of the O1 channel in water delivery. Employing site-directed mutagenesis we modified the two O1 channel bottleneck residues D1-E329 and CP43-V410 (T. vestitusnumbering) and probed water access and substrate exchange via time resolved membrane inlet mass spectrometry. Our data demonstrates that water reaches the Mn 4 CaO 5 cluster via the O1 channel in both wildtype and mutant PSII. In addition, the detailed analysis provides functional insight into the intricate protein-water-cofactor network near the Mn 4 CaO 5 cluster that includes the pentameric, near planar ‘water wheel’ of the O1 channel.

Plant Sciences↗
DOE OSTI2021

High resolution measurements reveal abiotic and biotic mechanisms of elevated nitric oxide emission after wetting dry soil

Wetting dry soil triggers emission of nitric oxide (NO), which can harm air quality and influence ecosystem N balance. NO released after wetting may be derived from two primary mechanisms: (1) abiotic decomposition of nitrite (NO 2 -) present in the dry soil and (2) biologically-mediated production of NO. The relative contributions of these mechanisms to NO emission are challenging to partition. To differentiate the two mechanisms, we made continuous observations of NO emission from a range of soils that varied in texture, pH, and exchangeable cations. Additionally, we coupled NO gas exchange measurements with automated, non-destructive high-resolution sampling of inorganic N species via microdialysis. We identified two distinct phases of NO production (1) an initial phase that reached its maximum less than 30 min after rewetting; and (2) a second phase lasting up to 36 h. The magnitude of the initial phase of NO production was correlated with the initial nitrous acid concentration (calculated from NO 2 - concentrations and soil pH) and soil exchangeable calcium. The second phase of NO emission coincided with a peak in NO 2 - that preceded NO 3 - accumulation. Together, these results suggest that NO emissions following wetting are defined by an initial pulse of abiotic NO formation mediated by soil acidity at mineral surfaces, followed by a prolonged pulse of NO emission driven by a lag between the biological processes of ammonia oxidation and nitrite oxidation. These results can inform mechanistic models of NO emissions from soils to improve predictions of the terrestrial N cycle and atmospheric chemistry.

54 ENVIRONMENTAL SCIENCES↗