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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 757 records · Page 42
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Hexagonal boron nitride (h-BN) irradiated with 140 MeV protons

Here, hexagonal boron nitride was irradiated with 140 MeV protons to a fluence of ~6 10 20 p/cm 2 at T irr ~200 °C. Isotropic graphite was also irradiated alongside h-BN under similar conditions and fluence to enable direct comparison of the two similar structures. The effects of proton irradiation on dimensional stability and microstructure were studied using precision dilatometry and energy dispersive Xray diffraction techniques revealing by direct comparison to graphite that h-BN can better resist radiation damage from bombardment when irradiated with protons impinging normal to the crystallographic planes or along the crystallographic c-axis. X-ray diffraction experiments also revealed a preferred orientation of the crystallites in bulk samples near the sample surface, an orientation influenced by irradiation. Thermal studies using differential scanning calorimetry and thermogravimetric analysis to 740 °C, augmented by precision dilatometry, provided evidence of subtle phase transitions attributed to residual w-BN in the matrix. Irradiation appears to induce shifting of such transitions.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Overcoming Barriers in Electrochemical Toluene Hydrogenation for Efficient Hydrogen Storage by Pt 3 Au Alloy Catalysts

Hydrogen storage and transportation are essential for the hydrogen economy, and liquid organic hydrogen carriers (LOHCs), such as a toluene/methylcyclohexane (TOL/MCH) system, offer significant advantages in terms of safety and efficiency. However, the electrochemical reduction of TOL to MCH (TER) faces challenges from competing with the hydrogen evolution reaction (HER) and catalyst instability. Here, in this study, Pt 3 Au is introduced as a highly effective catalyst for TER. Through density functional theory screening, we identified distinctive properties of Pt 3 Au, including enhanced binding to the TER intermediates and effective HER suppression. Experimental validation confirmed these computational predictions, with Pt 3 Au achieving the highest reported Faradaic efficiency (98%) in proton exchange membrane systems. Moreover, long-term testing demonstrated that Pt 3 Au maintained Faradaic efficiencies of >90% over 9 h, highlighting its robustness and operational stability. By integrating computational modeling and experimental evaluation, this work addresses key limitations in LOHC catalysis. Pt 3 Au establishes a benchmark for selective and stable TER performance, paving the way for advanced hydrogen storage technologies. These findings emphasize the critical role of rational catalyst design in overcoming the challenges associated with scalable and efficient hydrogen storage solutions.

LOHC↗
DOE OSTI2025

Aspen Open Jets: unlocking LHC data for foundation models in particle physics

Foundation models are deep learning models pre-trained on large amounts of data which are capable of generalizing to multiple datasets and/or downstream tasks. This work demonstrates how data collected by the CMS experiment at the Large Hadron Collider can be useful in pre-training foundation models for HEP. Specifically, we introduce the AspenOpenJets (AOJs) dataset, consisting of approximately 178 M high p T jets derived from CMS 2016 Open Data. We show how pre-training the OmniJet-α foundation model on AOJs improves performance on generative tasks with significant domain shift: generating boosted top and QCD jets from the simulated JetClass dataset. In addition to demonstrating the power of pre-training of a jet-based foundation model on actual proton–proton collision data, we provide the ML-ready derived AOJs dataset for further public use.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2021

Developing a Fundamental Knowledge Base for the Interaction of Ruthenium with Natural and Engineered Iron-Bearing Materials

The intent of this project is to build a fundamental knowledge base concerning the redox coupling between Ru and Fe in heterogeneous systems with predictive applications towards the fate, speciation, and transport of Ru in the environment and its capture using available technologies. RuNOCl 3 and Fe 3+ are redox active over a broad range of pH. Initial assessment of effect of redox coupling between Ru and Fe indicates that Fe(III) in ferrihydrite can oxidize Ru 2+ in RuNOCl3 to Ru(IV) during coprecipitation at ambient conditions and alkaline pH. Further, evidence suggests that Ru(IV) is incorporated in the structure of fh. Likewise, Fe 3+ (aq) also reduces Ru 2+ in RuNOCl 3 in the homogenous system at acidic pH although the kinetics of reaction appear to be slow. Rufh annealed to 500 0C transforms to Ru(III) doped hematite. AIMD informed EXAFS indicates that Ru substitutes for Fe(III) in regular octahedral sites of hematite but requires three distinct configurations involving edge-sharing protonated Fe vacancies and straight substitution with no local defects. Fe 2+ (aq) appears to oxidize at the surface of RuO 2 , but the amount is too low to reasonably expect detectable reduced Ru. Future experiments at higher pH are warranted to make Fe 2+ (aq) less stable (i.e., make more redox active). We also demonstrated that we can functionalize Si aerogels with Fe(II) and Fe(III) but likely need to go to higher T to make Feo nanoparticles.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Radiation damage of a two-dimensional carbon fiber composite (CFC)

Carbon fiber composites (CFC) are, among other applications, already in use as low-impedance collimating elements for intercepting TeV-level protons machines, like the CERN Large Hadron Collider. Towards a comprehensive understanding of these materials’ properties and behavior, a series of radiation damage campaigns have been undertaken in order to quantitively investigate the response of AC-150 K CFC to high proton fluences. The CFCs dimensional changes, stability, micro-structural evolution, and structural integrity below and above 5 × 10 20 p/cm 2 fluence threshold were studied. The irradiating particles were protons of kinetic energies in the range of 130–200 MeV. The effects of the irradiation temperature (~90–180°C and 280–500°C) combined with the proton fluence on the dimensional stability and the microstructural evolution of this anisotropic two-dimensional composite structure were studied using precision dilatometry and X-ray diffraction. Our results shed light on the fluence-based limitations for these composite materials. Furthermore, we compare these results with reference unirradiated graphite, and we discuss the similarities and differences in the dimensional changes and post-irradiation annealing properties.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Structural characterization of ligand binding and pH-specific enzymatic activity of mouse Acidic Mammalian Chitinase

Chitin is an abundant biopolymer and pathogen-associated molecular pattern that stimulates a host innate immune response. Mammals express chitin-binding and chitin-degrading proteins to remove chitin from the body. One of these proteins, Acidic Mammalian Chitinase (AMCase), is an enzyme known for its ability to function under acidic conditions in the stomach but is also active in tissues with more neutral pHs, such as the lung. Here, we used a combination of biochemical, structural, and computational modeling approaches to examine how the mouse homolog (mAMCase) can act in both acidic and neutral environments. We measured kinetic properties of mAMCase activity across a broad pH range, quantifying its unusual dual activity optima at pH 2 and 7. We also solved high-resolution crystal structures of mAMCase in complex with oligomeric GlcNAcn, the building block of chitin, where we identified extensive conformational ligand heterogeneity. Leveraging these data, we conducted molecular dynamics simulations that suggest how a key catalytic residue could be protonated via distinct mechanisms in each of the two environmental pH ranges. These results integrate structural, biochemical, and computational approaches to deliver a more complete understanding of the catalytic mechanism governing mAMCase activity at different pH. Engineering proteins with tunable pH optima may provide new opportunities to develop improved enzyme variants, including AMCase, for therapeutic purposes in chitin degradation.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2021

A measurement of proton-carbon forward scattering in a proof-of-principle test of the EMPHATIC spectrometer

The next generation of long-baseline neutrino experiments will be capable of precision measurements of neutrino oscillation parameters, precision neutrino-nucleus scattering, and unprecedented sensitivity to physics beyond the Standard Model. Reduced uncertainties in neutrino fluxes are necessary to achieve high precision and sensitivity in these future precise neutrino measurements. New measurements of hadron-nucleus interaction cross sections are needed to reduce uncertainties of neutrino fluxes. We report measurements of the differential cross-section as a function of scattering angle for proton-carbon interactions with a single charged particle in the final state at beam momenta of 20, 30, and 120 GeV/c. These measurements are the result of a beam test for EMPHATIC, a hadron-scattering and hadron-production experiment. The total, elastic and inelastic cross-sections are also extracted from the data and compared to previous measurements. These results can be used in current and future long-baseline neutrino experiments, and demonstrate the feasibility of future measurements by an upgraded EMPHATIC spectrometer.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2025

Charged-particle multiplicity distributions over a wide pseudorapidity range in p–Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV

This paper presents the primary charged-particle multiplicity distributions in proton–lead collisions at a centre-of-mass energy per nucleon–nucleon collision of $\sqrt{s_{NN}}$ = 5.02 TeV. The distributions are reported for non-single diffractive collisions in different pseudorapidity ranges. The measurements are performed using the combined information from the Silicon Pixel Detector and the Forward Multiplicity Detector of ALICE. The multiplicity distributions are parametrised with a double negative binomial distribution function which provides satisfactory descriptions of the distributions for all the studied pseudorapidity intervals. The data are compared to models and analyzed quantitatively, evaluating the first four moments (mean, standard deviation, skewness, and kurtosis). The shape evolution of the measured multiplicity distributions is studied in terms of KNO variables and it is found that none of the considered models reproduces the measurements. This paper also reports on the average charged-particle multiplicity, normalised by the average number of participating nucleon pairs, as a function of the collision energy. The multiplicity results are then compared to measurements made in proton–proton and nucleus–nucleus collisions across a wide range of collision energies.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2020

Structure of the respiratory MBS complex reveals iron-sulfur cluster catalyzed sulfane sulfur reduction in ancient life

Abstract Modern day aerobic respiration in mitochondria involving complex I converts redox energy into chemical energy and likely evolved from a simple anaerobic system now represented by hydrogen gas-evolving hydrogenase (MBH) where protons are the terminal electron acceptor. Here we present the cryo-EM structure of an early ancestor in the evolution of complex I, the elemental sulfur (S 0 )-reducing reductase MBS. Three highly conserved protein loops linking cytoplasmic and membrane domains enable scalable energy conversion in all three complexes. MBS contains two proton pumps compared to one in MBH and likely conserves twice the energy. The structure also reveals evolutionary adaptations of MBH that enabled S 0 reduction by MBS catalyzed by a site-differentiated iron-sulfur cluster without participation of protons or amino acid residues. This is the simplest mechanism proposed for reduction of inorganic or organic disulfides. It is of fundamental significance in the iron and sulfur-rich volcanic environments of early earth and possibly the origin of life. MBS provides a new perspective on the evolution of modern-day respiratory complexes and of catalysis by biological iron-sulfur clusters.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2025

Valence 1⁢𝑠−0⁢𝑑 proton vacancy of the 32 Si ground state

The 32 Si( 3 He,d) 33 P reaction was studied in inverse kinematics at 6.3 MeV/u. States in 33 P corresponding to the proton 1s-0d single-particle orbitals were identified up to ≈ 4.5 MeV in excitation energy. The ( 3 He,d) spectroscopic factors were determined from distorted-wave Born approximation calculations. When combined with complementary neutron-adding data, the 1s-0d proton vacancies in the 32 Si ground state were extracted. In conjunction with a reanalysis of data from previous single-particle measurements, the trends in proton and neutron vacancy were explored across the 28,30,32,34 Si isotopes. Both proton and neutron vacancy data show gradual changes in their occupancies. The proton 1s 1/2 orbitals in 32 Si and 34 Si are both consistent with being empty. In conclusion, the ground-state nucleon distributions are described by shell-model calculations constrained to the 1s-0d model space.

Watwood, N. [Argonne National Laboratory (ANL), Ar↗
NASA NTRS1991

The interactions of atmospheric cosmogenic radionuclides with spacecraft surfaces

The discovery of the cosmogenic radionuclide Be-7 on the front surface of the Long Duration Exposure Facility (LDEF) has opened new opportunities to study several unexplored regions of space science. The experiments have shown that the Be-7 found was concentrated in a thin surface layer of spacecraft material. The only reasonable source of the isotope is the atmosphere through which the spacecraft passed. It is expected that the uptake of Be in such circumstances will depend on the chemical form of the Be and the chemical nature of the substrate. It was found that the observed concentration of Be-7 does differ between metal surfaces and organic surfaces such as PTFE (Teflon). It is noted however, that (1) organic surfaces are etched by the atomic oxygen found under these orbital conditions, and (2) the relative velocity of the species is 8 km/s relative to the surface and the interaction chemistry and physics may differ from the norm. Be-7 is formed by disintegration of O and N nuclei under cosmic ray proton bombardment. Many other isotopes are produced by cosmic ray reactions, and some of these are suited to measurement by the extremely sensitive methods of accelerator mass spectrometry.

Gregory, John C.↗
DOE OSTI2023

Irradiation-assisted cracking of SA508-304L weldments with 308L groove filler and 309L butter in hot water immersion constant rate extension tests

Low alloy SA508 bainitic steel is often welded to 300 series austenitic stainless steel in nuclear power plants. These dissimilar metal weldments use 309L butter applied to the low alloy steel and 308L groove filler material to join the 309L to austenite. High alloy steels (such as the 308L and 309L material used here) have been identified as having greater susceptibility to irradiation-assisted stress corrosion cracking (IASCC). Evidence is presented here of cracking under tensile loads in 309L weldment butter in LWR hydrothermal conditions that correlates irradiation induced changes at δ ferrite–γ austenite phase boundaries and γ–γ grain boundaries; specifically intergranular Cr 23 C 6 precipitates. Cracking is not observed in irradiated 308L groove filler under the same conditions. Both the 309L butter and 308L filler material have a duplex or mixed δ–γ phase microstructure due to solidification during the welding procedure. We have performed constant extension rate autoclave immersion tests in BWR normal water chemistry hot water (288 °C, 10 MPa, 2000 wt. ppb dissolved oxygen, <100 nS/cm conductivity, neutral pH) of proton irradiated (2 MeV, approximately 3 displacements per atom at a depth of 10 μm) tensile specimens. Proton irradiation to the dpa levels used here induced Cr 23 C 6 carbide precipitation at γ–γ grain boundaries and δ–γ phase boundaries in the 309L butter but not the 308L filler. Cracking was observed in the proton-irradiated volume of 309L at these interfaces in the vicinity of the Cr 23 C 6 precipitates. We hypothesis the SA508 is the source of carbon in the 309L butter. Cr depletion at γ–γ grain boundaries was also observed and may also be a root cause of cracking. Furthermore, the 309L butter is under significant tensile residual stress in the weldment that adds to applied tensile loads and this too may be a contributing factor.

309L weld butter↗
DOE OSTI2022

Efficient electrocatalytic valorization of chlorinated organic water pollutant to ethylene

Electrochemistry can provide an efficient and sustainable way to treat environmental waters polluted by chlorinated organic compounds. However, the electrochemical valorization of 1,2-dichloroethane (DCA) is currently challenged by the lack of a catalyst that can selectively convert DCA in aqueous solutions into ethylene. Here, in this work, we report a catalyst comprising cobalt phthalocyanine molecules assembled on multiwalled carbon nanotubes that can electrochemically decompose aqueous DCA with high current and energy efficiencies. Ethylene is produced at high rates with unprecedented ~100% Faradaic efficiency across wide electrode potential and reactant concentration ranges. Kinetic studies and density functional theory calculations reveal that the rate-determining step is the first C–Cl bond breaking, which does not involve protons—a key mechanistic feature that enables cobalt phthalocyanine/carbon nanotube to efficiently catalyse DCA dechlorination and suppress the hydrogen evolution reaction. The nanotubular structure of the catalyst enables us to shape it into a flow-through electrified membrane, which we have used to demonstrate >95% DCA removal from simulated water samples with environmentally relevant DCA and electrolyte concentrations.

Choi, Chungseok↗
DOE OSTI2022

Supramolecular assemblies of polybenzimidazole and aromatic polycarboxylic acids with superior mechanical and H 2 /CO 2 separation properties

Aromatic polycarboxylic acids complex with imidazoles, forming supramolecular assemblies. Herein, we demonstrate that polybenzimidazole (PBI) can be augmented by aromatic polycarboxylic acids, including phthalic acid (PA), trimesic acid (TMA), and pyromellitic acid (PMA), and the resulting supramolecular assemblies exhibit attractive H 2 /CO 2 separation performance for precombustion carbon capture. The acid doping decreases the free volume and gas permeability but increases H 2 /CO 2 selectivity, which can be correlated with the molar ratio of the protons to PBI repeating units in the assemblies. Increasing the temperature decreases the H 2 /CO 2 selectivity because of weakened interactions. When challenged with model gas mixtures, a supramolecular assembly based on TMA shows H 2 /CO 2 separation properties superior to state-of-the-art materials and above Robeson's upper bound. Furthermore, this study elucidates the fruitful harnessing of dynamic non-covalent bonds to design robust and highly selective membranes for industrial gas separations.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Proton Collective Quantum Tunneling Induces Anomalous Thermal Conductivity of Ice under Pressure

Proton tunneling is believed to be nonlocal in ice, but its range has been shown to be limited to only a few molecules. Here, we measured the thermal conductivity of ice under pressure up to 50 GPa and found it increases with pressure until 20 GPa but decreases at higher pressures. We attribute this nonmonotonic thermal conductivity to the collective tunneling of protons at high pressures, supported by large-scale quantum molecular dynamics simulations. The collective tunneling loops span several picoseconds in time and are as large as nanometers in space, which match the phonon periods and wavelengths, leading to strong phonon scattering at high pressures. Finally, our results show direct evidence of global quantum motion existing in high-pressure ice and provide a new perspective to understanding the coupling between phonon propagation and atomic tunneling.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Progression of herpesvirus infection remodels mitochondrial organization and metabolism

Viruses target mitochondria to promote their replication, and infection-induced stress during the progression of infection leads to the regulation of antiviral defenses and mitochondrial metabolism which are opposed by counteracting viral factors. The precise structural and functional changes that underlie how mitochondria react to the infection remain largely unclear. Here we show extensive transcriptional remodeling of protein-encoding host genes involved in the respiratory chain, apoptosis, and structural organization of mitochondria as herpes simplex virus type 1 lytic infection proceeds from early to late stages of infection. High-resolution microscopy and interaction analyses unveiled infection-induced emergence of rough, thin, and elongated mitochondria relocalized to the perinuclear area, a significant increase in the number and clustering of endoplasmic reticulum-mitochondria contact sites, and thickening and shortening of mitochondrial cristae. Finally, metabolic analyses demonstrated that reactivation of ATP production is accompanied by increased mitochondrial Ca 2+ content and proton leakage as the infection proceeds. Overall, the significant structural and functional changes in the mitochondria triggered by the viral invasion are tightly connected to the progression of the virus infection.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2023

Detectors and diagnostics for multiprobe radiography using high-energy short-pulse lasers

Multiprobe radiography requires the following diagnostic capabilities at minimum: radiographic source diagnostics, spectroscopy, imaging, and tomography diagnostics. Depending on the repetition rate of the radiation sources, the diagnostics may be a single-shot diagnostic, such as photographic (radiochromic and X-ray films for high energy photons) films, or a multiple-shot diagnostic for repetitive source operations, such as a high-speed framing camera. Due to the drastically different detector physics of electrons, photons at different energies (keV to 10s of MeV in the radiography context), heavy ions such as protons, alphas, and neutrons, see, for example, Ref. [1, 2] for an overview, different types or configurations of detectors and constructions may be required for multiprobe radiography applications. Some of the common detector metricsinclude, independent of the particle/photon species, sensitivities or efficiency, energy resolution, spatial or temporal resolutions and others. Some unique detection scenarios arise in a multiprobe radiography setting, for example, crosstalk mitigation and particle identification (ID) when X-ray and higher energy photons, relativistic electrons, neutrons, other hadrons, and heavy particles coexist at the detector location.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2021

Research on Chemically Deuterated Cellulose Macroperformance and Fast Identification

Chemically deuterated cellulose fiber was expected to provide novel applications due to its spectral, biological, and kinetic isotope effect. In this research, the performance of the chemically deuterated cotton fibers, including their mechanical property, enzymatic degradation performance, effect on bacterial treatment, and fast identification (near-infrared modeling) was investigated. The breaking tenacity of the deuterated cotton fibers was slightly lower, which might be attributed to the structural damage during the chemical deuteration. The glucose yield by enzymatic hydrolysis was less than that of the protonic cotton fibers, implying the deuterated fibers are less sensitive to enzymatic degradation. Furthermore, the deuterated fibers could promote the growth of bacteria such as Escherichia. coli, which was associated with the released low-level deuterium content. At last, the near-infrared technique combined with partial least squares regression successfully achieved a fast identification of the protiated and deuterated cotton fibers, which significantly promoted the potential application of deuterated cellulose as anticounterfeiting materials (e.g., special paper).

59 BASIC BIOLOGICAL SCIENCES↗