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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

BETO 2021 Peer Review - Separations in Support of Arresting Anaerobic Digestion

In support of the Bioenergy Technologies Office in converting waste feedstocks to fuels and chemicals, this project develops and demonstrates an advanced system for the production of platform carboxylic acids by Arresting Anaerobic Digestion (AAD) of wet waste feedstocks. The project addresses three technology barriers in developing the bioeconomy; (1) Feedstock availability and cost (2) Selective separation of organic acid species, and (3) First-of-a-kind technology development. This project has developed an advanced AAD system with separations that can operate in high solids environments (> 10 wt.%) and is net positive in energy consumption compared to the energy content of the carboxylic acids. Operating an in situ product recovery (ISPR) system in high solids is required for fermentation produced intermediates beyond ethanol that have volatilities less than water (e.g. carboxylic acids). Carboxylic acids form a versatile platform for the production of renewable diesel fuel, aviation fuel, monomers, and chemicals. A high solids ISPR system expands the feedstocks for AAD, which have been restricted to thin stillage, to solid food waste. Additionally, current AAD technology employs separations that consume >200x the energy content of the produced acids. This project has developed and demonstrated the first AAD technology with ISPR that is net negative in energy value and operates in solids contents >10 wt.% to produce a mixed carboxylic acid product that is carbon negative.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2025

Nitrogen limitation causes a seismic shift in redox state and phosphorylation of proteins implicated in carbon flux and lipidome remodeling in Rhodotorula toruloides

Background: Oleaginous yeast are prodigious producers of oleochemicals, offering alternative and secure sources for applications in foodstuff, skincare, biofuels, and bioplastics. Nitrogen starvation is the primary strategy used to induce oil accumulation in oleaginous yeast as part of a global stress response. While research has demonstrated that post-translational modifications (PTMs), including phosphorylation and protein cysteine thiol oxidation (redox PTMs), are involved in signaling pathways that regulate stress responses in metazoa and algae, their role in oleaginous yeast remain understudied and unexplored. Results: Towards linking the yeast oleaginous phenotype to protein function, we integrated lipidomics, redox proteomics, and phosphoproteomics to investigate Rhodotorula toruloides under nitrogen-rich and starved conditions over time. Our lipidomics results unearthed interactions involving sphingolipids and cardiolipins with ER stress and mitophagy. Our redox and phosphoproteomics data highlighted the roles of the AMPK, TOR, and calcium signaling pathways in regulation of lipogenesis, autophagy, and oxidative stress response. As a first, we also demonstrated that lipogenic enzymes including fatty acid synthase are modified as a consequence of shifts in cellular redox states due to nutrient availability. Conclusions: We conclude that lipid accumulation is largely a consequence of carbon rerouting and autophagy governed by changes to PTMs, and not increases in the abundance of enzymes involved in central carbon metabolism and fatty acid biosynthesis. Our systems-level approach sets the stage for acquiring multidimensional data sets for protein structural modeling and predicting the functional relevance of PTMs using Artificial Intelligence/Machine Learning (AI/ML). Coupled to those bioinformatics approaches, the putative PTM switches that we delineate will enable advanced metabolic engineering strategies to decouple lipid accumulation from nitrogen limitation.

Lipid Signalling↗
DOE OSTI2020

Transmittal of the Sandia National Laboratories/New Mexico Five-Day Report for the Accidental Slug Discharge at the Albuquerque Bernalillo County Water Utility Authority (ABCWUA) Industrial Wastewater Permit No. 2069 Outfall [Letter and Enclosure]

This letter represents the five-day written notification for elevated fluoride levels at the Building 858N, Acid Waste Neutralization (AWN) System in accordance with the ABCWUA Sewer Use and Wastewater Ordinance § 3-6-5(B), Reports of Potential Problems. This AWN System is covered under the ABCWUA Industrial Wastewater Permit No. 2069G. The immediate notification to the ABCWUA occurred at 21:42 on August 1, 2019.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2023

CRISPR-Cas based system for targeting single-stranded sequences

The present invention relates to a CRISPR-Cas based system for targeting nucleic acid sequences. In part, the invention relates to synthetic guiding components for targeting single-stranded sequences, as well as design principles for constructing such components. Also described herein are methods of employing such components, e.g., to repress or activate a desired target within the subject.

Negrete, Oscar↗
DOE OSTI2020

Role of Silica Support in Phosphoric Acid Catalyzed Production of p -Xylene from 2,5-Dimethylfuran and Ethylene

p-Xylene is a commodity chemical of industrial importance for terephthalic acid production, for which renewable sourcing from naturally abundant lignocellulosic biomass is highly desired. Previous work demonstrated that phosphoric acid stabilized on siliceous zeolite supports (e.g., P-BEA, P-SPP) exhibits high selectivity toward p-xylene (>97%) from 2,5-dimethylfuran (DMF) and ethylene. However, the effect of the support and the contribution of heterogeneous versus homogeneous phosphoric acid on the observed catalytic behavior in the solvated reaction system have not been addressed. Here, we determine the phosphoric acid catalytic activity for DMF conversion and its selectivity to p-xylene when it is supported on a silica support as well as in the absence of a support. Specifically, phosphoric acid catalysis was studied in three different scenarios: (1) phosphoric acid was added in the liquid reaction mixture in the absence of any solid support, (2) phosphoric acid was added in the liquid reaction mixture along with inert silica support including siliceous zeolite (i.e., allowing for phosphoric acid–support assembly to proceed in the reaction mixture), and (3) phosphoric acid was first impregnated on the siliceous zeolite support and then the preassembled supported phosphoric acid catalyst was added in the liquid reaction mixture. We found that the reaction rate and selectivity to p-xylene are different in the above scenarios reflecting the effect of the solid support on the catalytic performance of phosphoric acid. In scenario 1, a low concentration of phosphoric acid (1.7 mM) in the absence of any solid support exhibited high selectivity to p-xylene (80% selectivity to p-xylene at 60% conversion of DMF), which decreased with increasing acid concentration. The selectivity to p-xylene and activity of phosphoric acid significantly increased by adding a silica support into the reaction system (scenario 2). Furthermore, this improvement was attributed to phosphoric acid partial association with the surface of the silica support under the reaction conditions (in situ catalyst assembly). Phosphoric acid predeposited on siliceous zeolite supports (e.g., P-BEA, P-SPP) synthesized via impregnation prior to the reaction (scenario 3) catalyzed the reaction heterogeneously without noticeable leaching and exhibited the highest activity and selectivity to p-xylene, suggesting an important role of the silica support and the need to ensure that phosphoric acid acts as a heterogeneous catalyst in order to accomplish selective conversion of DMF to p-xylene.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Ascorbic Acid Stability and pH Testing to Support RWM-018 Pilot Scale Wellhead Treatment System Feasibility Determination

A multitude of groundwater remediation techniques for chlorinated volatile organic compounds (cVOCs) have been conducted at the A/M-Areas of the Savannah River Site (SRS). Historical in-situ chemical oxidation (ISCO) injections of potassium permanganate and sodium persulfate conducted in 2018 and 2020, have left residual oxidant concentrations in the A/M-Area groundwater system. ISCO events targeted dense non-aqueous phase liquids (DNAPLs) through the injection of strong oxidants within plume zones upgradient of current groundwater recovery wells RWM-008 and RWM-018. These residual oxidants could significantly impede the operation of the mercury removal system needed to meet National Pollutant Discharge Elimination System (NPDES) permit requirements for the ongoing pump-and-treat system that hydraulically controls potions of the A/M-Area plume. Effluent treated groundwater from this system is discharged to surface water at the receiving outfall of the M-1 Air Stripper. To prevent interference of the M-1 Air Stripper system by residual oxidants, groundwater recovery has been ceased at well RWM-018. Modeling of oxidant transport in A/M-Area from ISCO estimated that the potential oxidant load contributed by RWM-018 could be as high as 120 mg/L. It is also possible that oxidants may be contributed via pumping at well RWM-008 in the near future as residual oxidants within the aquifer migrate toward its zone of influence. Savannah River National Laboratory (SRNL) has conducted research to investigate potential pre-treatment chemicals to neutralize these residual oxidants, before reaching the M-1 Air Stripper, to allow for resumed groundwater recovery at RWM-018 and continued pumping at RWM-008. Deployment of ascorbic acid for neutralization of residual oxidants at RWM-018 (and possibly RWM-008) is recommended based on results from previous reductant testing (SRNL, 2021). For a maximum estimated oxidant load at RWM-0018, a well-head treatment system would need to dose about 400 gallons of ascorbic acid each month to ensure complete neutralization. A second system with additional reagent should also be considered for deployment at RWM-008.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2025

Cross-Scale Catalyst Modeling Applied to H 2 Storage and Release via Formic Acid

Here, we propose the Systems-to-Atoms (S2A) modeling framework that integrates the kinetics of reaction chemistry and structural configurations across various length scales with the aim of establishing a versatile template for multiscale modeling of reactive flow problems and to predict the operando activity of catalyst materials. The approach encompasses a microkinetic model to analyze surface reactions on individual facets of catalyst nanoparticles coupled with the computation of average surface reaction rates for catalyst nanoparticles of specific size distributions. Macro-homogeneous surface reaction kinetics are derived as a function of catalyst loading and used as input parameters for the continuum-scale reactor model. The cross-scale framework enables the optimization of catalyst utilization through reactor design and operating strategy. To demonstrate the framework, we studied the storage and release of hydrogen from formic acid, a promising liquid organic hydrogen carrier (LOHC), over Pd, Pt, and Cu catalysts. The framework predicts observed trends in formic acid dehydrogenation activity for catalysts with comparable weight loadings and metal particle diameters, demonstrating satisfactory quantitative alignment. Finally, the seamless transmission of parameter uncertainties between scales is also discussed.

08 HYDROGEN↗
DOE OSTI2023

Induced phase transformation in ionizable colloidal nanoparticles

Abstract Acid–base equilibria directly influence the functionality and behavior of particles in a system. Due to the ionizing effects of acid–base functional groups, particles will undergo charge exchange. The degree of ionization and their intermolecular and electrostatic interactions are controlled by varying the pH and salt concentration of the solution in a system. Although the pH can be tuned in experiments, it is hard to model this effect using simulations or theoretical approaches. This is due to the difficulty in treating charge regulation and capturing the cooperative effects in a colloidal suspension with Coulombic interaction. In this work, we analyze a suspension of ionizable colloidal particles via molecular dynamics (MD) simulations, along with Monte Carlo simulations for charge regulation (MC-CR) and derive a phase diagram of the system as a function of pH. It is observed that as pH increases, particles functionalized with acid groups change their arrangement from face-centered cubic (FCC) packing to a disordered state. We attribute these transitions to an increase in the degree of charge polydispersity arising from an increase in pH. Our work shows that charge regulation leads to amorphous solids in colloids when the mean nanoparticle charge is sufficiently high. Graphical abstract

36 MATERIALS SCIENCE↗
DOE OSTI2022

Solvents and slurries comprising a poly(carboxylic acid) binder for silicon electrode manufacture

A binder solution for manufacturing silicon-based anodes useful for lithium-ion electrochemical cells is described herein. The binder solution comprises a poly(carboxylic acid) binder dissolved in a mixed solvent system comprising an amide solvent of Formula I, as described herein, and a second solvent which can be water and/or an organic solvent. The binder preferably comprises poly(acrylic acid). The mixed solvent system comprises about 10 to about 99 vol % of the amide solvent of Formula I. The binder solution is utilized as a solvent for a slurry of silicon-containing particles for preparing a silicon-containing electrode. The slurries made with the mixed solvent systems have higher viscosity and are more stable than slurries containing the same concentrations of silicon particle, carbon particles, and binder in water as the sole solvent.

Zhang, Lu↗
DOE OSTI2024

Solvents and slurries comprising a poly(carboxylic acid) binder for silicon electrode manufacture

An silicon-containing electrode is formed by coating a silicon-containing slurry onto a conductive current collector. The slurry comprises a binder solution comprising a poly(carboxylic acid) binder dissolved in a mixed solvent system comprising an amide solvent of Formula I, as described herein, and a second solvent which can be water and/or an organic solvent. The binder preferably comprises poly(acrylic acid). The mixed solvent system comprises about 10 to about 99 vol % of the amide solvent of Formula I. The binder solution is utilized as a solvent for a slurry of silicon-containing particles for preparing the silicon-containing electrode. The slurries comprising the mixed solvent system have higher viscosity and are more stable than slurries containing the same concentrations of silicon particles, carbon particles, and binder in water as the sole solvent.

Zhang, Lu↗
DOE OSTI2020

Method and apparatus for purifying nucleic acids and performing polymerase chain reaction assays using an immiscible fluid

Embodiments of the present invention are directed toward devices, systems, and methods for purifying nucleic acids to conduct polymerase chain reaction (PCR) assays. In one example, a method includes generating complexes of silica beads and nucleic acids in a lysis buffer, transporting the complexes through an immiscible fluid to remove interfering compounds from the complexes, further transporting the complexes into a density medium containing components required for PCR where the nucleic acids disassociate from the silica beads, and thermocycling the contents of the density medium to achieve PCR. Signal may be detected from labeling agents in the components required for PCR.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Mitigating cerium migration for perfluorosulfonic acid membranes using organic ligands

Improving the electrochemical stability of proton exchange membranes is a pressing priority for heavy-duty fuel cell vehicles. The lifetime of the most widely used perfluorosulfonic acid membranes is limited by reactive free radicals generated inside the system. Cerium has been found to reduce the chemical degradation of the membranes. However, cerium migration during fuel cell operation limits the chemical durability enhancement effect expected from the radical scavenging activity of cerium. Here we investigate a wide range of organic immobilizers for cerium, measuring their suitability concerning cerium retention, radical scavenging activity, and fuel cell performance. We report that partially fluorinated phosphonic acids enhance cerium retention up to 45 times and reduce fluoride emission rate by 38% compared to the commercial Nafion™ XL membrane pre-impregnated with cerium. The energetics of cerium-phosphonic acid complex systems by density functional theory calculations rationalizes effective cerium immobilization.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2022

Mitigating cerium migration for perfluorosulfonic acid membranes using organic ligands

Improving the electrochemical stability of proton exchange membranes is a pressing priority for heavy-duty fuel cell vehicles. The lifetime of the most widely used perfluorosulfonic acid membranes is limited by reactive free radicals generated inside the system. Cerium has been found to reduce the chemical degradation of the membranes. However, cerium migration during fuel cell operation limits the chemical durability enhancement effect expected from the radical scavenging activity of cerium. Here we investigate a wide range of organic immobilizers for cerium, measuring their suitability concerning cerium retention, radical scavenging activity, and fuel cell performance. Further, we report that partially fluorinated phosphonic acids enhance cerium retention up to 45 times and reduce fluoride emission rate by 38% compared to the commercial Nafion™ XL membrane pre-impregnated with cerium. The energetics of cerium-phosphonic acid complex systems by density functional theory calculations rationalizes effective cerium immobilization.

25 ENERGY STORAGE↗
DOE OSTI2020

Metabolic Signaling Cascades Prompted by Glutaminolysis in Cancer

Aberrant glutamatergic signaling has been implicated in altered metabolic activity and the demand to synthesize biomass in several types of cancer including melanoma. In the last decade, there has been a significant contribution to our understanding of metabolic pathways. An increasing number of studies are now emphasizing the importance of glutamate functioning as a signaling molecule and a building block for cancer progression. To that end, our group has previously illustrated the role of glutamatergic signaling mediated by metabotropic glutamate receptor 1 (GRM1) in neoplastic transformation of melanocytes in vitro and spontaneous development of metastatic melanoma in vivo. Glutamate, the natural ligand of GRM1, is one of the most abundant amino acids in humans and the predominant excitatory neurotransmitter in the central nervous system. Elevated levels of glutaminolytic mitochondrial tricarboxylic acid (TCA) cycle intermediates, especially glutamate, have been reported in numerous cancer cells. Herein, we highlight and critically review metabolic bottlenecks that are prevalent during tumor evolution along with therapeutic implications of limiting glutamate bioavailability in tumors.

Shah, Raj (ORCID:0000000204400189)↗
DOE OSTI2026

Ir–Ru Particles Enable Low-Loading Acidic Oxygen Evolution for Integrated Solar Devices

Integrated photoelectrochemical (PEC) devices for water splitting represent a compelling pathway for sustainable hydrogen production, directly converting solar energy into chemical fuels. While alkaline systems have achieved state-of-the-art solar-to-hydrogen (STH) efficiencies above 20% using earth-abundant catalysts, acidic PEC architectures provide unique advantages for compact device integration, fast proton transport, and stable operation under highly dynamic solar conditions. Proton-exchange membrane (PEM)-based configurations enable high current densities, low gas crossover, and rapid ionic response, making them especially well-suited for intermittent, bias-free PEC operation, despite alkaline electrolysis being more technologically mature. A critical limitation of acidic PEC systems remains, the oxygen evolution reaction (OER), which currently relies on scarce and costly iridium catalysts, restricting scalability. Here, in this study, we report a series of low-iridium mixed-metal oxide catalysts synthesized via a surfactant-assisted borohydride reduction method. An optimized Ir 0.5 Ru 0.5 O x catalyst exhibits exceptional intrinsic activity (>400 A g –1 Ir at 1.55 V vs RHE) in 0.1 M HClO 4 and maintains stable operation for over 10 days in an integrated PEC flow-cell. Sustained hydrogen production is achieved at 1.65 V with a total iridium loading of only 0.1 mg cm –2 , substantially below commercial PEM benchmarks. These results demonstrate a viable pathway toward scalable, high-performance acidic PEC hydrogen technologies.

Acidic electrolysis↗
DOE OSTI2025

Environmental photosensitizers can exhibit enhanced actinic absorption in microhydrated clusters compared to solution

Brown carbon chromophores at environmental air-water interfaces often act as photosensitizers that absorb sunlight and subsequently transfer energy to nearby molecules, initiating a wide variety of chemical reactions. Despite their importance to understanding daytime chemistry at these airwater interfaces, little is known about the role of the solvation environment on the photophysical properties of these photosensitizers. In this work, we present a joint experimental-theoretical study of the vibrational and photophysical properties of microhydrated protonated and deprotonated 4-benzoylbenzoic acid (4-BBA), a key model system for environmental photosensitizers. We find that for protonated 4-BBAH + ∙(H 2 O) 0-1 , representing photosensitizers in very acidic conditions, a single bright state dominates the UV-Vis spectrum between 280 and 400 nm. Comparing the experimental UV-Vis spectra and quantum chemistry-predicted spectra of 4-BBA + ∙(H 2 O) 0-2 , we find that the degree of microhydration has little effect on the UV-Vis spectra or the orbitals of the dominant feature. For deprotonated 4-BBA ‒ , representing photosensitizers in basic conditions, quantum chemistry calculations predict that the UV-Vis spectra are ~3x weaker in intensity than the brightest 4-BBAH + ∙(H 2 O) 0-1 features and were not observed experimentally. Quantum chemistry calculations predict one dominant UV-Vis feature is present in the spectra of 4-BBA ‒ ∙(H 2 O) 0-2 , which exhibit minor shifts with degree of microhydration. While 4-BBA in bulk solution over a range of pH values has relatively weak absorption within the solar actinic region, we show that microhydrated 4-BBA has bright transitions within the actinic region. This indicates that the complex structure of environmental air-water interfaces can shift the absorption maximum of photosensitizers into the actinic region for enhanced absorption of sunlight and subsequent enhancement of photosensitizer-driven reactions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Dynamic, hollow nanotubular networks with superadjustable pH-responsive and temperature resistant rheological characteristics

Recently, the interest in stimuli-responsive and adaptable materials has continuously grown in various fields and applications. For such responsive systems, different triggers, including pH, light, pressure, temperature, and electric field, have been utilized to control dynamics and assembly. Among these, pH is one of the most convenient, energy-efficient, and economic modalities. Besides, plenty of traditional materials have poor thermal and salt stability, limiting their applications. Herein, we report a new design of a pH-responsive viscoelastic supramolecular complex (VSC) based on commplexation of a new long-chain amino-amide and maleic acid. In this study, the system demonstrated a sol–gel-sol transition from pH 2 to 10, with the largest static viscosity occurring at pH 6 (~1000 Pa·s) and the smallest viscosity at pH 4 (~3.3 Pa·s), indicating ~ 300-fold control over the viscosity. For a given concentration, the static viscosity of VSC was about 15 times larger than that of CTAB/NaSal, a well-established dynamic viscoelastic system, and no pH-responsiveness was observed for the traditional system. In addition, the VSC demonstrated a superior temperature tolerance and lower temperature dependence. The potential of these intriguing dynamics viscoelastic systems was evaluated for hydraulic fracturing and enhanced oil recovery applications. Proppant settling velocity of DMAA/MA was 500 ~ 1000 times lower than that of CTAB/NaSal and common traditional polymers. Likewise, the oil recovery percentage could be significantly improved with the utilization of DMAA/MA compared to the CTAB/NaSal (86 % vs 52 %). Aside from applications in hydraulic fracturing and enhanced oil recovery, we anticipate that the intriguing rheological properties of this viscoelastic system can be beneficial for other chemical engineering applications including personal care products, cosmetics, lubricants, and biomedical gels.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗