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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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17 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

A learned closure method applied to phase mixing in a turbulent gradient-driven gyrokinetic system in simple geometry

We present a new method for formulating closures that learn from kinetic simulation data. We apply this method to phase mixing in a simple gyrokinetic turbulent system – temperature-gradient-driven turbulence in an unsheared slab. The closure, called the learned multi-mode (LMM) closure, is constructed by, first, extracting an optimal basis from a nonlinear kinetic simulation using singular value decomposition. Subsequent nonlinear fluid simulations are projected onto this basis and the results are used to formulate the closure. We compare the closure with other closures schemes over a broad range of the relevant two-dimensional parameter space (collisionality and gradient drive). We find that the turbulent kinetic system produces phase-mixing rates much lower than the linear expectations, which the LMM closure is capable of capturing. We also compare radial heat fluxes. A Hammett–Perkins closure, generalized to include collisional effects, is quite successful throughout the parameter space, producing ${\sim }14\,\%$ root-mean-square (r.m.s.) error. The LMM closure is also very effective: when trained at three (two) points (in a 35 point parameter grid), the LMM closure produces $8\,\%$ ( $12\,\%$ ) r.m.s. errors. The LMM procedure can be readily generalized to other closure problems.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2024

Revisiting leptonic nonunitarity

In the presence of extra neutrino states at high scales, the low-energy effective 3 × 3 leptonic mixing matrix (LMM) is in general nonunitary. We revisit the question of what is our current knowledge of individual LMM matrix elements without assuming unitarity. We first demonstrate that a minimal set of experimental constraints suffices in bounding LMM nonunitarity parameters to the level of O ( 10 − 3 ) , without the use of neutrino oscillation data. We then revisit oscillation results as a complementary cross-check, using different physics and different experimental techniques to probe a similar parameter space. We correct some common misconceptions in the neutrino nonunitarity literature resulting from an incautious treatment of input parameters. We find that neutrino oscillation experiments can constrain LMM nonclosure, but, contrary to claims in the literature, are completely insensitive to the overall normalization of the LMM. Thus, we conclude that oscillation experiments, including the future DUNE experiment, have no power in excluding nonunitarity altogether. Published by the American Physical Society 2024

Astronomy & Astrophysics↗
DOE OSTI2022

High Performance Flow Battery with Inexpensive Inorganic Reactants: DAYS Program (Final Technical Report)

RTRC’s DAYS projects focused on new flow battery (FB) chemistries for long duration energy storage: one that pairs aqueous polysulfide and manganese active materials in strongly alkaline electrolytes (S/Mn); another explores ligand-modified metal (LMM) chemistries in moderate pH electrolyte conditions. The S/Mn chemistry met durability targets by running for over 500 cycles and 1000 hours. Combined with this durability, power densities of up to 60 mW/cm2 at 80% round-trip efficiency, and exceptionally low-cost S and Mn active materials, the S/Mn FB offers a pathway to meeting the <5¢/kW-hr levelized cost of storage (LCOS) target first proposed by the DAYS Program and accepted by the DOE Energy Storage Grand Challenge. The LMM chemistry made impressive progress as well, including durability tests that retained performance over 600 hours of cycling. Cell optimization allowed this chemistry to operate as high as 500 mW/cm2 at 80% round-trip efficiency, nearly 10x the power density of S/Mn and comparable to the power density achieved in RTRC’s flow battery stacks using acidic vanadium battery solutions. This enabled the LMM chemistry to also offer a pathway to the <5¢/kW-hr LCOS DAYS and DOE targets. The promising results from the LMM chemistry have led to a recent DOE AMO award to advance the technology to a 5 kW, 20 kW-hr prototype.

25 ENERGY STORAGE↗
DOE OSTI2020

Identification of Novel Genomic Associations and Gene Candidates for Grain Starch Content in Sorghum

Starch accumulated in the endosperm of cereal grains as reserve energy for germination serves as a staple in human and animal nutrition. Unraveling genetic control for starch metabolism is important for breeding grains with high starch content. In this study, we used a sorghum association panel with 389 individuals and 141,557 single nucleotide polymorphisms (SNPs) to fit linear mixed models (LMM) for identifying genomic regions and potential candidate genes associated with starch content. Three associated genomic regions, one in chromosome (chr) 1 and two novel associations in chr-8, were identified using combination of LMM and Bayesian sparse LMM. All significant SNPs were located within protein coding genes, with SNPs ∼ 52 Mb of chr-8 encoding a Casperian strip membrane protein (CASP)-like protein (Sobic.008G111500) and a heat shock protein (HSP) 90 (Sobic.008G111600) that were highly expressed in reproductive tissues including within the embryo and endosperm. The HSP90 is a potential hub gene with gene network of 75 high-confidence first interactors that is enriched for five biochemical pathways including protein processing. The first interactors of HSP90 also showed high transcript abundance in reproductive tissues. The candidates of this study are likely involved in intricate metabolic pathways and represent candidate gene targets for source-sink activities and drought and heat stress tolerance during grain filling.

genomics↗
DOE OSTI2019

Real-world outcomes in patients with unresected stage III non-small cell lung cancer

This study examined real-world clinical outcomes such as progression-free survival (PFS), time to metastasis (TTM), overall survival (OS), and health-related quality of life (HRQOL) in patients with unresected stage III non-small cell lung cancer (NSCLC) treated in the community setting. A retrospective review of medical records extracted from 10 US community oncology practices was conducted. Eligible patients were adults diagnosed with stage III NSCLC from 1/1/2011 to 3/1/2016 without evidence of surgical resection within 6 months after stage III NSCLC diagnosis (index date). PFS, OS, and TTM were assessed from the index date, and were analyzed using Kaplan–Meier and Cox regression analyses. HRQOL was assessed for a subset of patients using a patient-reported measure, the 86-item Patient Care Monitor (PCM). Linear mixed models (LMM) were used to assess the impact of patient characteristics and change in PCM scores associated with progression. Among the sample of 478 patients, median PFS (95% confidence interval) was 10 months (9–11), median OS was 20 months (17–22), and median TTM was 30 months (23–45). Most patients (58.2%) experienced disease progression, which the LMM showed to be associated with significant worsening of physical symptoms and psychological states (p < 0.001). This study documented PFS and OS consistent with published literature. The majority of patients experienced disease progression, which was associated with worsening of HRQOL. These findings highlighted the need for better therapeutic options in patients with unresected stage III NSCLC with potential to improve patient outcomes and HRQOL.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2019

Structure and Mechanism of LcpA, a Phosphotransferase That Mediates Glycosylation of a Gram-Positive Bacterial Cell Wall-Anchored Protein

ABSTRACT The widely conserved LytR-CpsA-Psr (LCP) family of enzymes in Gram-positive bacteria is known to attach glycopolymers, including wall teichoic acid, to the cell envelope. However, it is undetermined if these enzymes are capable of catalyzing glycan attachment to surface proteins. In the actinobacterium Actinomyces oris , an LCP homolog here named LcpA is genetically linked to GspA, a glycoprotein that is covalently attached to the bacterial peptidoglycan by the housekeeping sortase SrtA. Here we show by X-ray crystallography that LcpA adopts an α-β-α structural fold, akin to the conserved LCP domain, which harbors characteristic catalytic arginine residues. Consistently, alanine substitution for these residues, R149 and R266, abrogates GspA glycosylation, leading to accumulation of an intermediate form termed GspA LMM , which is also observed in the lcpA mutant. Unlike other LCP proteins characterized to date, LcpA contains a stabilizing disulfide bond, mutations of which severely affect LcpA stability. In line with the established role of disulfide bond formation in oxidative protein folding in A. oris , deletion of vkor , coding for the thiol-disulfide oxidoreductase VKOR, also significantly reduces LcpA stability. Biochemical studies demonstrated that the recombinant LcpA enzyme possesses pyrophosphatase activity, enabling hydrolysis of diphosphate bonds. Furthermore, this recombinant enzyme, which weakly interacts with GspA in solution, catalyzes phosphotransfer to GspA LMM . Altogether, the findings support that A. oris LcpA is an archetypal LCP enzyme that glycosylates a cell wall-anchored protein, a process that may be conserved in Actinobacteria , given the conservation of LcpA and GspA in these high-GC-content organisms. IMPORTANCE In Gram-positive bacteria, the conserved LCP family enzymes studied to date are known to attach glycopolymers, including wall teichoic acid, to the cell envelope. It is unknown if these enzymes catalyze glycosylation of surface proteins. We show here in the actinobacterium Actinomyces oris by X-ray crystallography and biochemical analyses that A. oris LcpA is an LCP homolog, possessing pyrophosphatase and phosphotransferase activities known to belong to LCP enzymes that require conserved catalytic Arg residues, while harboring a unique disulfide bond critical for protein stability. Importantly, LcpA mediates glycosylation of the surface protein GspA via phosphotransferase activity. Our studies provide the first experimental evidence of an archetypal LCP enzyme that promotes glycosylation of a cell wall-anchored protein in Gram-positive bacteria.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

In Situ Monitoring of H 2 -Induced Nonstoichiometry in Cu 2 O

Nonstoichiometry plays a pivotal role in the functioning of oxide materials, but it is challenging to measure the non-stoichiometric formation and the resulting charge redistribution around the point defects. Using ambient-pressure X-ray photoelectron spectroscopy and Auger electron spectroscopy to monitor the reduction of Cu 2 O in H 2 , we identify the formation of an intermediate, oxygen-deficient Cu 2 O phase and its progressive inward growth into the deeper region of the oxide. Complemented by DFT modeling, we show that the oxygen-deficient Cu 2 O formation occurs via molecular H 2 adsorption at the Cu 2 O surface, which results in the loss of lattice O from the formation of H 2 O molecules that desorb spontaneously from the oxide surface. The resulting oxy-gen-deficient Cu 2 O is a stable intermediate that persists before the Cu 2 O is fully reduced to metallic Cu. The O vacancy induced charge redistribution of the coordinating Cu atoms results in a satellite feature in Cu LMM, which can be used a fingerprint to identify the nonstoichiometry and local charge transfer in non-stoichiometric oxides.

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

Optimal Control of the Energy-Saving Hybrid Hydraulic-Electric Architecture (HHEA) for Off-Highway Mobile Machines

Most off-highway constructions and agriculture equipment use hydraulics, which has unmatched power density, for power transmission and throttling as a means for control. A novel hybrid hydraulic-electric architecture (HHEA) has recently been proposed to improve efficiency for high-power machines that would have been cost-prohibitive to electrify directly. HHEA uses a set of common pressure rails (CPRs) to transmit the majority of power hydraulically and small electric motor drives to modulate that power and to achieve precise control. This article proposes a computationally efficient Lagrange multiplier method (LMM) for computing the optimal sequence of pressure rail selections to minimize energy use. This is needed to evaluate HHEA's energy-saving potential and for iterative architecture design and sizing. An interesting complication is that the cost function is not fully defined until the candidate control sequence is fully specified. This issue is dealt with by decomposing the original problem into a set of sub-problems with additional constraints that can be solved efficiently. Computational effort can be further reduced if actuators are optimized individually instead of together. However, additional steps are required to prevent the constraint functions from becoming discontinuous with respect to the Lagrange multipliers, which is necessary for meeting the constraints. Lastly, a case study of a construction machine demonstrates the efficacy of the method and shows that the HHEA reduces energy consumption by 68%-73% compared to the baseline load-sensing architecture.

Lagrange multiplier↗
DOE OSTI2019

Lithium-based transition-metal oxides for battery electrodes analyzed by x-ray photoelectron spectroscopy. I. LiNi 0.8 Co 0.15 0.05 O 2

X-ray photoelectron spectroscopy (XPS) was used to analyze fresh LiNi 0.8 Co 0.1 5Al 0.05 O 2 powder obtained from TODA America. XP spectra were obtained using incident monochromatic Al Kα radiation at 0.834 01 nm. A survey spectrum together with Ni 2p, Co 2p, Ni LMM, O 1s, C 1s, Al 2s, Ni 3s, Co 3s, Al 2p, Ni 3p, Co 3p, and Li 1s are presented. The spectra indicate the principal core level photoelectron and Auger electron signals and show carbon with only minor sulfur contamination. Making use of the O 1s, Al 2s, Ni 3p, Co 3p, Li 1s lines and neglecting the components related to surface contaminants, XPS quantitative analysis reveals an altered stoichiometry of the air-exposed powder surface of LiNi 0.2 Co 0.03 Al 0.1 O 0.7 .

25 ENERGY STORAGE↗
DOE OSTI2019

Lithium-based transition-metal oxides for battery electrodes analyzed by x-ray photoelectron spectroscopy. II. LiNi 0.8 Co 0.1 Mn 0.1 O 2

X-ray photoelectron spectroscopy (XPS) was used to analyze fresh LiNi 0.8 Co 0.1 Mn 0.1 O 2 powder obtained from Targray Technology International, Inc.. XP spectra were obtained using incident monochromatic Al Kα radiation at 0.834 01 nm. A survey spectrum together with Ni 2p, Co 2p, Mn 2p, Ni LMM, O 1s, C 1s, Al 2s, Ni 3s, Co 3s, Mn 3s, Ni 3p, Co 3p, Li 1s, and Mn 3p are presented. The spectra indicate the principal core level photoelectron and Auger electron signals and show only minor sulfur contamination. Making use of the O 1s, Ni 3p, Co 3p, Mn 3p, Li 1s lines and neglecting the components related to surface contaminants, XPS quantitative analysis reveals an altered stoichiometry of the air-exposed powder surface of LiNi 0.4 Co 0.02 Mn 0.1 O 0.8 .

25 ENERGY STORAGE↗
DOE OSTI2019

Lithium-based transition-metal oxides for battery electrodes analyzed by x-ray photoelectron spectroscopy. III. LiNi 0.6 Co 0.2 Mn 0.2 O 2

X-ray photoelectron spectroscopy (XPS) was used to analyze fresh LiNi 0.6 Co 0.2 Mn 0.2 O 2 powder obtained from Ecopro Company, Ltd.. XP spectra were obtained using incident monochromatic Al Kα radiation at 0.834 01 nm. A survey spectrum together with Ni 2p, Co 2p, Mn 2p, Ni LMM, O 1s, C 1s, Al 2s, Ni 3s, Co 3s, Mn 3s, Ni 3p, Co 3p, Li 1s, and Mn 3p are presented. The spectra indicate the principal core level photoelectron and Auger electron. Making use of the O 1s, Ni 3p, Co 3p, Mn 3p, Li 1s lines and neglecting the components related to surface contaminants, XPS quantitative analysis reveals an altered stoichiometry of the air-exposed powder surface of LiNi 0.2 Co 0.05 Mn 0.1 O 0.7 .

25 ENERGY STORAGE↗
DOE OSTI2019

Lithium-based transition-metal oxides for battery electrodes analyzed by x-ray photoelectron spectroscopy. IV. LiNi 0.5 Co 0.2 Mn 0.3 O 2

X-ray photoelectron spectroscopy (XPS) was used to analyze two lots of fresh LiNi 0.5 Co 0.2 Mn 0.3 O 2 powder and one of the two lot of LiNi0.5Co0.2Mn0.3O2 powder recalcined in air at 750 °C obtained from TODA America. XP spectra were obtained using incident monochromatic Al Kα radiation at 0.83401 nm. A survey spectrum together with Ni 2p, Co 2p, Mn 2p, Ni LMM, O 1s, C 1s, Al 2s, Ni 3s, Co 3s, Mn 3s, Ni 3p, Co 3p, Li 1s, and Mn 3p are presented. The spectra indicate the principal core level photoelectron and Auger electron signals and show only minor sulfur contamination. Making use of the O 1s, Ni 3p, Co 3p, Mn 3p, Li 1s lines and neglecting the components related to surface contaminants, XPS quantitative analysis reveals an altered stoichiometry of the air-exposed powder surfaces for the first lot, the first lot recalcined, and the second lot of LiNi0.3Co0.1Mn0.2O1.2, LiNi 0.4 Co 0.1 Mn 0.3 O 1.5 , and LiNi 0.4 Co 0.1 Mn 0.2 O 1.3 , respectively

25 ENERGY STORAGE↗
DOE OSTI2019

Lithium-based transition-metal oxides for battery electrodes analyzed by x-ray photoelectron spectroscopy. V. LiNi 0.4 Co 0.3 0.3 O 2

X-ray photoelectron spectroscopy (XPS) and x-ray-induced Auger electron spectroscopy were used to analyze untreated LiNi 0.4 Co 0.3 Mn 0.3 O 2 powder obtained from TODA America. X-ray photoelectron and x-ray-induced Auger electron spectra were obtained using incident monochromatic Al Kα radiation at 0.834 01 nm. A survey spectrum together with Ni 2p, Co 2p, Mn 2p, Ni LMM, O 1s, C 1s, Ni 3s, Co 3s, Mn 3s, Ni 3p, Co 3p, Li 1s, and Mn 3p are presented. The spectra indicate the principal core level photoelectron and Auger electron signals. Making use of the O 1s, Ni 3p, Co 3p, Mn 3p, and Li 1s lines and neglecting the components related to surface contaminants, XPS quantitative analysis reveals an altered stoichiometry of the air-exposed powder surface of LiN i0.4 Co 0.2 Mn 0.3 O 1.6 .

25 ENERGY STORAGE↗
DOE OSTI2019

Lithium-based transition-metal oxides for battery electrodes analyzed by x-ray photoelectron spectroscopy. VI. LiNi 0.4 Co 0.2 Mn 0.4 O 2

X-ray photoelectron spectroscopy (XPS) was used to analyze fresh LiNi 0.4 Co 0.2 Mn 0.4 O 2 powder obtained from TODA America. XP spectra were obtained using incident monochromatic Al Kα radiation at 0.834 01 nm. A survey spectrum together with Ni 2p, Co 2p, Mn 2p, Ni LMM, O 1s, C 1s, Al 2s, Ni 3s, Co 3s, Mn 3s, Ni 3p, Co 3p, Li 1s, and Mn 3p are presented. The spectra indicate the principal core level photoelectron and Auger electron. Making use of the O 1s, Ni 3p, Co 3p, Mn 3p, Li 1s lines and neglecting the components related to surface contaminants, XPS quantitative analysis reveals an altered stoichiometry of the air-exposed powder surface of LiNi 0.5 Co 0.2 Mn 0.5 O 1.9 .

25 ENERGY STORAGE↗
DOE OSTI2019

Lithium-based transition-metal oxides for battery electrodes analyzed by x-ray photoelectron spectroscopy. VII. LiNi 0.33 Co 0.33 Mn 0.33 O 2

X-ray photoelectron spectroscopy (XPS) was used to analyze fresh LiNi 0.33 Co 0.33 Mn 0.33 O 2 powder obtained from TODA America. XP spectra were obtained using incident monochromatic Al Kα radiation at 0.834 01 nm. A survey spectrum together with Ni 2p, Co 2p, Mn 2p, Ni LMM, O 1s, C 1s, Al 2s, Ni 3s, Co 3s, Mn 3s, Ni 3p, Co 3p, Li 1s, and Mn 3p are presented. The spectra indicate the principal core level photoelectron and Auger electron signals. Making use of the O 1s, Ni 3p, Co 3p, Mn 3p, Li 1s lines and neglecting the components related to surface contaminants, XPS quantitative analysis reveals an altered stoichiometry of the air-exposed powder surface of LiNi 0.4 Co 0.1 Mn 0.7 O 2.0 .

25 ENERGY STORAGE↗
DOE OSTI2019

Lithium-based transition-metal oxides for battery electrodes analyzed by x-ray photoelectron spectroscopy. VIII. Li 1.2 Ni 0.15 Co 0.1 Mn 0.55 O 2

X-ray photoelectron spectroscopy (XPS) and x-ray-induced Auger electron spectroscopy were used to analyze untreated Li 1.2 Ni 0.15 Co 0.1 Mn 0.55 O 2 powder obtained from TODA America. X-ray photoelectron and x-ray-induced Auger electron spectra were obtained using incident monochromatic Al Kα radiation at 0.83 01 nm. A survey spectrum together with Ni 2p, Co 2p, Mn 2p, Ni LMM, O 1s, C 1s, Ni 3s, Co 3s, Mn 3s, Ni 3p, Co 3p, Li 1s, and Mn 3p are presented. The spectra indicate the principal core level photoelectron and Auger electron signals. Making use of the O 1s, Ni 3p, Co 3p, Mn 3p, and Li 1s lines and neglecting the components related to surface contaminants, XPS quantitative analysis reveals an altered stoichiometry of the air-exposed powder surface of Li 1.2 Ni 0.4 Co 0.2 Mn 0.9 O 2.8 .

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2021

Molybdenum and silver photoemission survey spectra from hard x-rays

Electron emission from thick polished samples of polycrystalline molybdenum (Mo) and single crystalline $\langle$111$\rangle$ silver (Ag) was measured with hard x-ray photoemission spectroscopy. Six different excitation x-ray energies were used, nominally 8.0, 11.0, 13.0, 15.0, 18.0, and 21.5 keV. Survey spectra were recorded with each excitation to a kinetic energy of at most 15 keV, often capturing the entire emission range. The Mo 1s core peak was measured. Detailed LMM Auger spectra of Mo show marked increases in intensity and altered shape when x-ray energy exceeds the Mo 1s binding energy. The Mo and Ag L-shell photoelectron peaks are measured at four x-ray energies up to 18 keV showing the transition from 2p3/2 to 2s photoionization dominance.

47 OTHER INSTRUMENTATION↗