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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 1,639 records · Page 91

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NASA NTRS2017

Proton Testing of nVidia Jetson TX1

Single-Event Effects (SEE) testing was conducted on the nVidia Jetson TX1 System on Chip (SOC); herein referred to as device under test (DUT). Testing was conducted at Massachusetts General Hospitals (MGH) Francis H. Burr Proton Therapy Center on October 16th, 2016 using 200MeV protons. This testing trip was purposed to provide a baseline assessment of the radiation susceptibility of the DUT as no previous testing had been conducted on this component.

Proton testing↗

NASA NTRS2017

Proton Testing of nVidia GTX 1050 GPU

Proton testing↗

NASA NTRS2017

The Effects of Inhomogeneous Proton-Alpha Drifts on the Heating of the Solar Wind

Previous modeling studies have demonstrated that waves and super-Alfvenic drift can lead to perpendicular preferential heating of the alpha particles with respect to protons. Using a 2.5-D hybrid model of the solar wind alpha-proton plasma, we study the effects of inhomogeneous (across the magnetic field) background streaming focusing on the fast solar wind. We explore the effects of an initial relative, inhomogeneous ion drift on the perpendicular ion heating and cooling and consider the effects of solar wind expansion. We study the spectrum of the magnetic fluctuations in the inhomogeneous background solar wind and demonstrate the generation of oblique waves and their effects on enhanced resonant anisotropic ion heating. The model reproduces the typical ion temperature anisotropy values seen in observations. Using our model, we find that inhomogeneous super-Alfvenic ion drift in the plasma generates significant power of oblique waves in the solar wind plasma, in addition to enhanced heating compared to the non-drifting populations. We demonstrate the effects of various inhomogeneity profiles and regions of the drift on the ion anisotropic heating in super-Alfvenic and near-Alfvenic drifts. We find that the cooling effect due to the solar wind expansion is not significant when super-Alfvenic drifts are considered.

proton↗

NASA NTRS2018

Proton Testing of nVidia GTX 1050 GPU, Part 2

Single-Event Effects (SEE) testing was conducted on the nVidia GTX 1050 Graphics Processor Unit (GPU); herein referred to as device under test (DUT). Testing was conducted at Massachusetts General Hospital's (MGH) Francis H. Burr Proton Therapy Center on April 28th, 2018 using 200-MeV protons. This testing trip was purposed to provide additional radiation susceptibility data from payloads compiled in Q3FY18. While not all radiation-induced errors are critical, the effects on the application need to be considered. More so, failure of the device and an inability to reset itself should be considered detrimental to the application. Radiation effects on electronic components are a significant reliability issue for systems intended for space.

Single-Event Effects (SEE)↗

NASA NTRS2023

Global Ozone Loss Following Extreme Solar Proton Storms Based on the July 2012 Coronal Mass Ejection

Large solar coronal mass ejections pose a threat in the near-Earth space. As a cause of extreme periods of space weather, they can damage satellite-based communications and create geomagnetically induced currents in power and energy grids. Further, the solar wind energetic particles can reduce the protecting layer of atmospheric ozone and pose a threat to life on Earth. The large coronal mass ejection (CME) of July 2012, although directed away from the Earth, is often highlighted as a prime example of a potentially devastating super storm. Here we show, based on proton fluxes recorded by the instruments aboard the STEREO-A satellite, that the atmospheric response to the July 2012 event would have been comparable to those of the largest solar proton events of the satellite era. Significant impact on total ozone outside polar regions would require a much larger event, similar to those recorded in historical proxy data sets. Such an extreme event would cause long-term ozone reduction all the way to the equator and increase the size, duration, and depth of the Antarctic ozone hole. The impact would be comparable to predicted drastic and sudden ozone reduction from major volcanic eruptions, regional nuclear conflicts, or long-term stratospheric geoengineering.

ozone depletion↗

DOE OSTI2025

Multiple Coulomb scattering in acrylic of a 221.3 MeV therapeutic proton beam

Measurements of multiple Coulomb scattering (MCS) distributions for 221.3 MeV therapeutic protons are presented using a novel detector system comprised of a thin scintillator, a pellicle mirror, and a digital camera. The MCS distributions were characterized for three acrylic phantoms of varying lengths and for two biological density-equivalent phantoms simulating bone and muscle. Additionally, beam profiles were measured across an energy range of 80.3–221.3 MeV in 20 MeV increments. The observed energy dependence of the photon yields is consistent with the tabulated stopping power values. Finally, the experimental results are benchmarked against Geant4 simulations, demonstrating consistent agreement and validating the capability of the detector system for radiology measurements.

Digital camera↗

DOE OSTI2025

Coupling Interfacial Redox‐Reactions with In Situ Proton Generation for the Photoelectrochemical Separation of Rare‐Earth Elements

Abstract A dual‐function photoelectrochemical (PEC) separation system is demonstrated for rare‐earth element (REE) recovery. The sustainable release of the captured REEs is promoted through the synergistic integration of a redox‐reaction for electrostatic repulsion, and in situ proton generation for ion‐exchange, all driven by photoelectrochemistry. The platform consists of a redox‐copolymer, poly(ferrocenylpropyl methacrylamide‐ co ‐methacrylic acid) (P(FPMAm‐ co ‐MAA)) (PFM), conjugated with carbon nanotubes (CNTs) and coated onto titanium dioxide nanorods (TNRs). The (PFM‐CNT)/TNR spontaneously adsorbs up to 214.2 mg of Yttrium/g PFM by ion‐exchange, and demonstrates broad applicability for other REEs. The adsorbed REEs are released through the PEC oxidation of ferrocene (Fc) to ferrocenium (Fc + ), and the simultaneous PEC water splitting reactions at the TNRs that protonate the carboxylate binding groups. This dual photoelectrochemically‐driven mechanism for REE release is investigated by in situ pH measurements, as well as vibrational and X‐ray photoelectron spectroscopy. Through PEC approaches, a 68.8% reduction in energy consumption during REE recovery has been achieved compared to purely electrochemical systems, with a regeneration efficiency close to 100%. For NdFeB magnets from waste hard disk drives, Nd and Dy recovery efficiencies of 59.2 and 61.1% are achieved. The dual‐functionality of these copolymer PEC systems offers a sustainable platform for modulating critical element recovery.

Cho, Ki‐Hyun [Department of Chemical and Biomolecu↗

DOE OSTI2020

Protonation of CH 3 N 3 and CF 3 N 3 in Superacids: Isolation and Structural Characterization of Long‐Lived Methyl‐ and Trifluoromethylamino Diazonium Ions

Abstract The methylamino diazonium cations [CH 3 N(H)N 2 ] + and [CF 3 N(H)N 2 ] + were prepared as their low‐temperature stable [AsF 6 ] − salts by protonation of azidomethane and azidotrifluoromethane in superacidic systems. They were characterized by NMR and Raman spectroscopy. Unequivocal proof of the protonation site was obtained by the crystal structures of both salts, confirming the formation of alkylamino diazonium ions. The Lewis adducts CH 3 N 3 ⋅AsF 5 and CF 3 N 3 ⋅AsF 5 were also prepared and characterized by low‐temperature NMR and Raman spectroscopy, and also by X‐ray structure determination for CH 3 N 3 ⋅AsF 5 . Electronic structure calculations were performed to provide additional insights. Attempted electrophilic amination of aromatics such as benzene and toluene with methyl‐ and trifluoromethylamino diazonium ions were unsuccessful.

Saal, Thomas↗

DOE OSTI2022

Activating Nitrogen–doped Graphene Oxygen Reduction Electrocatalysts in Acidic Electrolytes using Hydrophobic Cavities and Proton–conductive Particles

Although pyridinic-nitrogen (pyri-N) doped graphene is highly active for the oxygen reduction reaction (ORR) of fuel cells in alkaline media, the activity critically decreases under acidic conditions. Herein we report on how to prevent the deactivation based on the mechanistic understanding that O 2 + pyri–NH ⁺ + e – → O 2,a + pyri–NH governs the ORR kinetics. First, we considered that the deactivation is due to the hydration of pyri-NH + , leading to a lower shift of the redox potential. Introducing the hydrophobic cavity prevented the hydration of pyri-NH + but inhibited the proton transport. We then increased proton conductivity in the hydrophobic cavity by introducing SiO 2 particles coated with ionic liquid polymer/Nafion® which kept the high onset potentials with an increased current density even in acidic media.

25 ENERGY STORAGE↗

DOE OSTI2025

Constructing Water‐Stable Porous Organic Salts via Suppressed Proton Integration Using Fluorinated Tetrazole Tectons

Porous organic salts (POSs) are an emerging class of materials with ordered ionic architectures, offering excellent proton transfer and water uptake properties. However, conventional POS synthesis via strong acid–base neutralization (e.g., ─SO₃H and ─NH₂) leads to extensive hydrogen bonding with water, compromising stability in aqueous and water-lean environments. Here, we address this challenge by designing POSs with hydrophobic porous channels and minimal hydrogen bonding formation. Our key innovation is the use of fluorinated tetrazole as a weak acid tecton and a tetra-substituted imidazole precursor devoid of active protons as the base. Single-crystal analysis and computational modeling reveal that the structural integrity of the synthesized POSs arises primarily from cation–anion interactions, with water confined as clusters in the pores, independent of hydrogen bonding with the scaffold. Robustness of the POS structure under aqueous and water-lean conditions is confirmed by X-ray and neutron scattering, as well as computational modeling, confirming preserved packing and crystal structures. The stability of POS is further demonstrated in aqueous iodine capture, with imidazolium cations and C–F functionalizations serving as strong adsorption sites. As a result, the approach developed herein further pushes the boundary of POS materials to withstand both aqueous and water-lean conditions.

Fluorinated tecton↗

DOE OSTI2021

Cobalt Carbonyl Clusters Enable Independent Control of Two Proton Transfer Rates in the Mechanism for Hydrogen Evolution

Abstract Metal carbonyl clusters (MCC's) are atomically defined nanomaterials which can be characterized using the precise tools of molecular (electro)chemistry. HER mechanisms involve two proton transfer (PT) steps in the catalytic cycle. For HER catalyzed by [Co 11 C 2 (CO) 23 ] 3− ( 1 3− ), cyclic voltammetry measurements were used to determine the rate for PT1 as k PT1 =3×10 8 M −1 s −1 , whereas the rate for PT2 is k PT2 =3.7×10 3 M −1 s −1 . The fast, diffusion‐limited rate for PT1 is consistent with a previous report describing [Co 13 C 2 (CO) 24 ] 4− ( 2 4− ), with PT=2.9×10 9 M −1 s −1 . In both cases rate enhancement in PT1 is promoted by the many Co−Co bonds on the surface of the MCC that serve as PT sites: a statistical enhancement of rate akin to the effects of proton relays. In contrast, k PT2 varies and is five orders of magnitude slower for 1 2− compared with 2 4− . Thus, MCC's and nanomaterials offer an opportunity to enhance the rate for PT1 while maintaining thermochemical or kinetic control of PT2.

Pattanayak, Santanu↗

DOE OSTI2022

First saturation correction in high energy proton-nucleus collisions. Part III. Ensemble averaging

In high energy proton-nucleus collisions, the gluon saturation effects from the nucleus are fully incorporated into the light-like Wilson lines. The gluon saturation effects from the proton, which are anticipated to be important either in the extreme high energy limit or towards the dense-dense (nucleus-nucleus) collision regimes, have been studied perturbatively within the Color Glass Condensate effective theory in previous papers of this series. A configuration-by-configuration expression for the single inclusive semi-hard gluon production including the first saturation correction was obtained. In this paper, we perform ensemble averaging in the McLerran-Venugopalan model and the Dipole Approximation. We find that, in the saturation correction, the effects of the initial state interactions are negligible while the final state interactions play most important role and give a positive-valued contribution to the semi-hard gluon spectrum. Furthermore, we show that the single gluon spectrum scales approximately 1/$k$$^{4}_{⊥}$ at small k ⊥ , suggesting that a resummation of higher order saturation corrections is required to regulate the infrared region of the gluon spectrum.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2020

Proton decay: flipped vs. unflipped SU(5)

We analyze nucleon decay modes in a no-scale supersymmetric flipped SU(5) GUT model, and contrast them with the predictions for proton decays via dimension-6 operators in a standard unflipped supersymmetric SU(5) GUT model. We find that these GUT models make very different predictions for the ratios Γ(p → π 0 µ + )/Γ(p → π 0 e + ), Γ(p → π + ν - )/Γ(p → π 0 e + ), Γ(p → K 0 e + )/Γ(p → π 0 e + ) and Γ(p → K 0 µ + )/Γ(p → π 0 µ + ), and that predictions for the ratios Γ(p → π 0 µ + )/Γ(p → π 0 e + ) and Γ(p → π + ν - )/Γ(p → π 0 e + ) also differ in variants of the flipped SU(5) model with normal- or inverse-ordered light neutrino masses. Upcoming large neutrino experiments may have interesting opportunities to explore both GUT and flavour physics in proton and neutron decays.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2021

First saturation correction in high energy proton-nucleus collisions. Part II. Single inclusive semi-hard gluon production

Exploiting recently obtained analytic solutions of classical Yang-Mills equations for higher order perturbations in the field of the dilute object (proton), we derive the complete first saturation correction to the single inclusive semi-hard gluon production in high energy proton-nucleus collisions by applying the Lehmann-Symanzik-Zimmermann reduction formula. We thus finalize the program started by Balitsky (see ref. [1]) and independently by Chirilli, Kovchegov and Wertepny (see ref. [2]) albeit using a very different approach to carry out our calculations. We extracted the functional dependence of gluon spectrum on the color charge densities of the colliding objects; thus our results can be used to evaluate complete first saturation correction to the double/multiple inclusive gluon productions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2025

Measurement of correlations among net-charge, net-proton, and net-kaon multiplicity distributions in Pb-Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV

Correlations among conserved quantum numbers, such as the net-electric charge, the net-baryon, and the net-strangeness in heavy-ion collisions, are crucial for exploring the QCD phase diagram. In this paper, these correlations are investigated using net-proton number (as a proxy for the net-baryon), net-kaon number (for the net-strangeness), and net-charged particle number in Pb-Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV with the ALICE detector. The observed correlations deviate from the Poissonian baseline, with a more pronounced deviation at LHC energies than at RHIC. Theoretical calculations of the Thermal-FIST hadron resonance gas model, HIJING, and EPOS LHC event generators are compared with experimental results, where a significant impact of resonance decays is observed. Thermal-FIST calculations under the grand canonical and canonical ensembles highlight significant differences, underscoring the role of local charge conservation in explaining the data. Recent lattice QCD studies have demonstrated that the magnetic field generated by spectator protons in heavy-ion collisions affects susceptibility ratios, in particular those related to the net-electric charge and the net-baryon numbers. The experimental findings are in qualitative agreement with the expectations of lattice QCD.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2020

Proton decay in supersymmetric SU(4) c × SU(2) L × SU(2) R

We discuss proton decay in a recently proposed model of supersymmetric hybrid inflation based on the gauge symmetry SU(4) c × SU(2) L × SU(2) R . A U(1) R symmetry plays an essential role in realizing inflation as well as in eliminating some undesirable baryon number violating operators. Proton decay is primarily mediated by a variety of color triplets from chiral superfields, and it lies in the observable range for a range of intermediate scale masses for the triplets. The decay modes include p → e + (μ + ) + π 0 , p→$\bar{ν}$+π + , p → K 0 + e + (μ + ), and p → K + +$\bar{ν}$, with a lifetime estimate of order 10 34 –10 36 yrs and accessible at Hyper-Kamiokande and future upgrades. The unification at the Grand Unified Theory (GUT) scale M GUT (~ 10 16 GeV) of the Minimal Supersymmetric Standard Model (MSSM) gauge couplings is briefly discussed.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2023

Polarized Proton Structure in the Resonance Region

In view of the precise data available on inclusive polarized electron scattering off polarized proton targets in the nucleon resonance excitation region, we compare these results with the coherent sum of resonant contributions to the polarized structure function g 1 and virtual photon asymmetry A 1 . To this goal, we employ the nucleon resonance electroexcitation amplitudes determined for photon virtualities Q 2 < 5.0 GeV 2 from analyses of the CLAS data on exclusive electroproduction off protons in the resonance region. Most of the well established resonances of four star PDG status in the mass range up to 1.75 GeV are included. We find that the resonance-like structures observed in the inclusive g 1 data are related to the resonant contributions in the entire range of photon virtuality Q 2 where the data on g 1 are available. In the range of invariant mass of the final hadron system W > 1.5 GeV, the data on the asymmetry A 1 are well reproduced even when accounting for resonant contributions only, especially for the larger values of Q 2 and energies analysed. This observation offers an interesting hint to quark-hadron duality seen in polarized inclusive electron scattering observables.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2022

Status on lattice calculations of the proton spin decomposition

Abstract Lattice calculations of the proton spin components is reviewed. The lattice results of the quark spin from the axial-vector current matrix element at ∼ 0.3−0.4 is smaller than those from the constituent quark models. This is largely due to the fact that the vacuum polarization contribution from the disconnected insertion is negative. Its connection with the anomalous Ward identity is clarified and verified numerically. This resolves the contentious issue in the “proton spin crisis.” The glue spin and angular momentum are found to be large and there is notable contribution from the quark orbital angular momentum. Renormalization, mixing, and normalization of the quark and glue angular momenta are discussed. With sufficient precision, they can be compared with more precise experimental measurements when the electron-ion collider facility is available.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗