SEARCH · Engineering Papers
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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Electronics Assurance and Development at SRNL • The Why: –Operational Technology –Electronics Manufacture & Subversion Example –Where Assurance Fits In • The Solution: –NA-121.4: Nuclear Enterprise Assurance (NEA) –NA-IM: Enterprise to OT – Bridging the Gap
Two beam abort system candidates of the Electron-Ion Collier (EIC) Electron Storage Ring (ESR) are devised and discussed. The proposed candidates are based on an existing Lambertson magnet in RHIC inventory, or a brand-new Septum magnet. A comprehensive comparison is provided in this article in support of the Record of Decision.
Isotopic engineering provides a powerful route to control phonon behavior in crystalline solids, enabling fundamental studies of lattice dynamics and heat transport at the atomic scale. Here, we directly visualize isotope-dependent phonon propagation in epitaxial Cr 2 O 3 using aberration-corrected scanning transmission electron microscopy (STEM) combined with monochromated, high-energy-resolution electron energy-loss spectroscopy (EELS). Guided by ab initio phonon calculations, we demonstrate that optical phonon modes above 70 meV are predominantly oxygen-derived and exhibit measurable redshifts upon substitution of natural 16 O by enriched 18 O. Spatially resolved vibrational spectrum imaging reveals isotope-enriched tracer layers within Cr 2 O 3 thin films, correlating isotope concentration with phonon intensity variations and vibrational energy shifts. At the nanometer and atomic scales, vibrational EELS mapping uncovers coherent phonon propagation across isotopic interfaces, consistent with theoretical phonon density of states and dispersion relations. These results establish vibrational EELS as a quantitative probe for isotope-dependent phonon transport in materials, opening new possibilities for studying energy dissipation and lattice dynamics.
Boron-containing materials are increasingly drawing interest for the use in electronics, optics, laser targets, neutron absorbers, and high-temperature and chemically resistant ceramics. In this article, the first investigation into the deposition of boron-based material via electron beam-induced deposition (EBID) is reported. Thin films were deposited using a novel, large-area EBID system that is shown to deposit material at rates comparable to conventional techniques such as laser-induced chemical vapor deposition. The deposition rate and stoichiometry of boron oxide fabricated by EBID using trimethyl borate (TMB) as precursor is found to be critically dependent on the substrate temperature. By comparing the deposition mechanisms of TMB to the conventional, alkoxide-based precursor tetraethyl orthosilicate it is revealed that ligand chemistry does not precisely predict the pathways leading to deposition of material via EBID. Lastly, the results demonstrate the first boron-containing material deposited by the EBID process and the potential for EBID as a scalable fabrication technique that could have a transformative effect on the athermal deposition of materials.
Abstract In magnetar crusts, magnetic fields are sufficiently strong to confine electrons into a small to moderate number of quantized Landau levels. This can have a dramatic effect on the crust's thermodynamic properties, generating field-dependent de Haas–van Alphen oscillations. We previously argued that the large-amplitude oscillations of the magnetic susceptibility could enhance the ohmic dissipation of the magnetic field by continuously generating small-scale, rapidly dissipating field features. This could be important to magnetar field evolution and contribute to their observed higher temperatures. To study this, we performed quasi-3D numerical simulations of electron MHD in a representative volume of neutron star crust matter, for the first time including the magnetization and magnetic susceptibility resulting from Landau quantization. We find that the potential enhancement in the ohmic dissipation rate due to this effect can be a factor ∼3 for temperatures of the order of 10 8 K, and ∼4.5 for temperatures of the order of 5 × 10 7 K, depending on the magnetic field configuration. The nonlinear Hall term is crucial to this amplification: without it, the magnetic field decay is only enhanced by a factor ≲2 even at 5 × 10 7 K. These effects generate a high wavenumber plateau in the magnetic energy spectrum associated with the small-scale de Haas–van Alphen oscillations. Our results suggest that this mechanism could help explain the magnetar heating problem, though due to the effect's temperature-dependence, full magneto-thermal evolution simulations in a realistic stellar model are needed to judge whether it is viable explanation.
Abstract not provided
Experimental determination of electron concentrations and effective frequencies of electron collision with neutral particles in various gases behind reflected shock waves
Elastic scattering of slow electrons by two-electron ions
Thin film technique for determination of electron mean free path and free electron density changes in bulk metals under applied strain
Electron bursts in magnetotail and electron precipitation in auroral zone correlations, discussing balloons and Vela satellites observations
Energy spectra of electrons from pion-muon- electron decays in interstellar gas
Electron density, electron temperature, and earth magnetic field above Fort Churchill from rocket measurements
Electron bremsstrahlung produced in thick targets at incident electron energies of 0.2, 1.0, 2.0, and 2.8 MeV
Recombination rate of electrons in high pressure helium-like plasma with gas temperature fixed at 300 K and electron temperature varied between 300-2000 K
Free electron model for electron work functions and number density distributions and surface potentials in metals
Electric fields and electron work functions, surface potentials and number density distributions in selected metals surfaces determined using free electron model
Electron precipitation patterns and their relation to substorm increases in electrons at synchronous orbit
Electron bremsstrahlung shielding at synchronous altitude by electron trapping in dielectrics using Monte Carlo method