Synthesis and characterization of sintered H–Y zeolite-derived waste forms for dehalogenated electrorefiner salt
Not Available
Gardner, Levi D.↗
SEARCH · Engineering Papers
Results for “H-I”
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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Saturn i launch vehicle sa-8 and launch complex 37b functional systems description. volume viii- h-i engine and hydraulic system functional description, index of finding numbers, and mechanical schematics
Saturn I /SA-8/ launch vehicle and launch complex systems - H- 1 rocket engine, and hydraulic systems
LAUNCH COMPLEX↗
Effect of reduced dehalogenation on the performance of Y zeolite-based sintered waste forms
Not Available
Gardner, Levi (ORCID:0000000273277620)↗
Physical and Thermomechanical Properties of Yttrium Hydride from Large Scale Bulk Metal Hydriding Furnace
Given the superior thermal stability and highly attainable hydrogen density, yttrium hydride is an excellent high-temperature moderator material in advanced thermal neutron spectrum reactors that require small core volumes. Yttrium hydride has been selected as the moderator material for the Transformational Challenge Reactor, which was launched at Oak Ridge National Laboratory (ORNL) in 2019. However, fabrication of large-scale crack-free yttrium hydride is challenging and very limited efforts have been committed to the characterization of bulk yttrium hydride in response to the need to establish a complete database of the thermomechanical properties of YHx. In this report, the challenges associated with fabricating large-scale crack-free yttrium hydride are discussed herein. In response to those challenges, a hydriding system was designed and constructed at ORNL and was used to successfully fabricate crack-free yttrium hydride in complex geometries at large scales. This was accomplished by precisely controlling the hydrogen’s partial pressure and the retort temperature, which was informed by the well-established thermodynamic properties of the binary H-Y system. Hydrogen content in as-fabricated hydride was determined by the weight change method and vacuum hot extraction technique, complemented by the X-ray diffraction (XRD). In addition, significant efforts are being dedicated to establishing a complete database of the thermomechanical properties of as-fabricated yttrium hydride. In FY2020, we investigated the thermophysical properties of yttrium hydrides as a function of temperature (room temperature to 700°C) and hydrogen concentration (H/Y ratio ranges from 1.52 to 1.93). The results indicate that at the temperatures below 300 °C, the hydrogen content did not have a significant influence on the thermal expansion, while the specific heat capacity, the thermal diffusivity, and the calculated thermal conductivity were slightly higher for the higher H/Y ratio. Between 300°C and 700 °C, a reversible second-order endothermic transition in all measured thermal properties was observed. It was also found that the onset temperatures of the observed transition varied, with the composition having inverse dependence on the hydrogen content. An attempt was made to explain the behavior of the thermophysical properties at higher temperatures by considering the order– disorder transition as a result of hydrogen redistribution. In addition, nanoindentation was employed to determine the elastic modulus and hardness and to capture the crystal orientation dependence of these parameters. Vickers hardness was also reported. The final section of the report introduces ongoing neutron irradiation campaign of yttrium hydride.
22 GENERAL STUDIES OF NUCLEAR REACTORS↗
The warp of the Galactic stellar disk detected in IRAS source counts
About 90,000 IRAS point sources have been used as disk tracers in order to explore the possibility of warp in the Galactic stellar disk. The results imply that the Galactic stellar disk is warped at large radii in a way similar to the H-I layer, and that the warp is an important characteristic of the Galaxy as a whole. It is suggested that the warp may be a long-lasting phenomenon, possibly caused by asymmetries of the mass distribution in the outer regions of the Galactic dark halo.
Djorgovski, S.↗
Orbital mechanics and mission design; Proceedings of the AAS/NASA International Symposium, Greenbelt, MD, Apr. 24-27, 1989
The present conference discusses topics in LEO mechanics, the earth-sun-moon orbital regime, space navigation, and lunar and planetary missions. Attention is given to an improved technique for passive eccentricity control, H-I launch vehicle mission planning, glideslope approaches, the control of Space Station-based tethered systems, rendezvous operations in GEO, launch-window expansion and trajectory correction for the First Lunar Swingby, the nature of lunar gravity assists, and the numerical determination of libration-point trajectories with solar exclusion zone-avoiding out-of-plane maneuvers. Also discussed are the interferometric tracking of multiple spacecraft, an improved determination of Martian satellite orbits, the Magellan Venus Mapping Mission, the Mars Rover Sample Return Mission, round-trip trajectories for manned Mars exploration, advanced missions using fusion propulsion, Vesta trajectories and navigation, and Voyager interstellar mission design.
Teles, Jerome↗
HST-COS Observations on Hydrogen, Helium, Carbon, and Nitrogen Emission from the SN 1987A Reverse Shock
We present the most sensitive ultraviolet observations of Supernova 1987 A to date. Imaging spectroscopy from the Hubble Space Telescope-Cosmic Origins Spectrograph shows many narrow (Delta v approximates 300 km/s) emission lines from the circumstellar ring, broad Delta v approximates 10-20 x 10(exp 3) km/s) emission lines from the reverse shock, and ultraviolet continuum emission. The high signal-to-noise ratio (>40 per resolution element) broad Ly-alpha emission is excited by soft X-ray and EUV heating of mostly neutral gas in the circumstellar ring and outer supernova debris. The ultraviolet continuum at lambda > 1350 A can be explained by H-I two-photon (2s(exp 2)S(sub 1/2)-l(exp 2)S(sub 1/2)) emission from the same region. We confirm our earlier, tentative detection of N V lambda 1240 emission from the reverse shock and present the first detections of broad He II lambda1640, C IV lambda 1550, and N IV ] lambda1486 emission lines from the reverse shock. The helium abundance in the high-velocity material is He/H = 0.14 +/- 0.06. The N V /H alpha line ratio requires partial ion-electron equilibration (T(sub e)/T(sub p) approximately equal to 0.14-0.35). We find that the N/C abundance ratio in the gas crossing the reverse shock is significantly higher than that in the circumstellar ring, a result that may be attributed to chemical stratification in the outer envelope of the supernova progenitor. The N/C abundance may have been stratified prior to the ring expUlsion, or this result may indicate continued CNO processing in the progenitor subsequent to the expUlsion of the circumstellar ring.
France, Kevin↗
Emission from hadronic and leptonic processes in galactic jet-driven bubbles
ABSTRACT We investigate the multiwavelength emission from hadronic and leptonic cosmic rays (CRs) in bubbles around galaxies, analogous to the Fermi bubbles of the Milky Way. The bubbles are modelled using 3D magnetohydrodynamical simulations, and are driven by a 0.3 Myr intense explosive outburst from the nucleus of Milky Way-like galaxies. We compute their non-thermal emission properties at different stages throughout their evolution, up to 7 Myr, by post-processing the simulations. We compare the spectral and spatial signatures of bubbles with hadronic, leptonic, and hybrid hadro-leptonic CR compositions. These each show broadly similar emission spectra, comprised of radio synchrotron, inverse Compton, and non-thermal bremsstrahlung components. However, hadronic and hybrid bubbles were found to be brighter than leptonic bubbles in X-rays, and marginally less bright at radio frequencies, and in γ-rays between ∼0.1 and a few 10s of GeV, with a large part of their emission being driven by secondary electrons formed in hadronic interactions. Hadronic systems were also found to be slightly brighter in high-energy γ-rays than their leptonic counterparts, owing to the π0 decay emission that dominates their emission between energies of 100s of GeV and a few TeV.
Owen, Ellis R. (ORCID:0000000310526439)↗
Production efficiencies of sound waves in the intracluster medium driven by AGN jets
Feedback from active galactic nuclei (AGNs) is believed to be the most promising solution to the cooling flow problem in cool-core clusters. Dissipation of sound waves is considered as one of the possible heating mechanisms; however, its relative contribution to heating remains unclear. To estimate the energy budget for heating, we perform 3D hydrodynamic simulations of AGN jet injections in a Perseus-like cluster and quantify the amount of energy stored in the forms of weak shocks and waves. For this work, e find that, for a single jet injection with typical parameters in cool-core clusters, ${\sim}9{{\ \rm per\ cent}}$ of the total jet energy is stored in compressional waves (including both shocks and waves). However, due to the destructive effects among randomly phased waves as well as the dissipation of shock energies, in our simulations including self-regulated AGN feedback, no more than $3{{\ \rm per\ cent}}$ of the total injected energy goes into compressional waves. We further separate the energy contribution from shocks and waves and find that, for a single outburst, the shocks can only contribute to ${\sim}20{-}30{{\ \rm per\ cent}}$ of the total compressional energy in the inner radii and quickly dissipate away. In the self-regulated case where shocks are repeatedly generated, shocks completely dominate over sound waves in the inner region and can still provide ${\sim}40{-}50{{\ \rm per\ cent}}$ of the total compressional energy at outer radii. Our results suggest that the production of sound waves is not as efficient as what was previously found, and thus sound wave dissipation may be a subdominant source of heating in cool-core clusters.
79 ASTRONOMY AND ASTROPHYSICS↗
SN 2022ann: a Type Icn supernova from a dwarf galaxy that reveals helium in its circumstellar environment
Here, we present optical and near-infrared (NIR) observations of the Type Icn supernova (SN Icn) 2022ann, the fifth member of its newly identified class of SNe. Its early optical spectra are dominated by narrow carbon and oxygen P-Cygni features with absorption velocities of ∼800 km s −1 ; slower than other SNe Icn and indicative of interaction with a dense, H/He-poor circumstellar medium (CSM) that is outflowing slower than typical Wolf–Rayet wind velocities of >1000 km s −1 . We identify helium in NIR spectra 2 weeks after maximum and in optical spectra at 3 weeks, demonstrating that the CSM is not fully devoid of helium. Unlike other SNe Icn, the spectra of SN 2022ann never develop broad features from SN ejecta, including in the nebular phase. Compared to other SNe Icn, SN 2022ann has a low luminosity (o-band absolute magnitude of ∼−17.7), and evolves slowly. The bolometric light curve is well-modelled by 4.8 M ⊙ of SN ejecta interacting with 1.3 M ⊙ of CSM. We place an upper limit of 0.04 M ⊙ of 56 Ni synthesized in the explosion. The host galaxy is a dwarf galaxy with a stellar mass of 10 7.34 M ⊙ (implied metallicity of log(Z/Z ⊙ ) ≈ 0.10) and integrated star-formation rate of log (SFR) = −2.20 M ⊙ yr −1 ; both lower than 97 per cent of galaxies observed to produce core-collapse supernovae, although consistent with star-forming galaxies on the galaxy Main Sequence. The low CSM velocity, nickel and ejecta masses, and likely low-metallicity environment disfavour a single Wolf–Rayet progenitor star. Instead, a binary companion is likely required to adequately strip the progenitor and produce a low-velocity outflow.
79 ASTRONOMY AND ASTROPHYSICS↗
Evolution and feedback of AGN jets of different cosmic ray composition
Jet feedback from active galactic nuclei (AGN) is one of the most promising mechanisms for suppressing cooling flows in cool-core clusters. However, the composition of AGN jets and bubbles remains uncertain; they could be thermally dominated, or dominated by cosmic ray proton (CRp), cosmic ray electron (CRe), or magnetic energy. In this work, we investigate the evolution and feedback effects of CRp and CRe dominated jets by conducting 3D magnetohydrodynamic simulations of AGN jet-inflated bubbles in the intracluster medium using the FLASH code. We present the evolution of their energies, dynamics, and heating, and model their expected cavity-power versus radio-luminosity relation (P cav –L R ). We find that bubbles inflated by CRe dominated jets follow a very similar dynamical evolution to CRp dominated bubbles even though CRe within bubbles suffer significantly stronger synchrotron and inverse-Compton cooling. This is because, as CRe lose their energy, the jet-inflated bubbles quickly become thermally dominated within ∼30 Myr. Their total energy stops decreasing with CR energy and evolves similarly to CRp dominated bubbles. The ability of CRe and CRp dominated bubbles to heat the intracluster medium is also comparable; the cold gas formed via local thermal instabilities is well suppressed in both cases. The CRp and CRe bubbles follow different evolutionary trajectories on the P cav –L R plane, but the values are broadly consistent with observed ranges for FR-I sources. We also discuss observational techniques that have potential for constraining the composition of AGN jets and bubbles.
79 ASTRONOMY AND ASTROPHYSICS↗
Materials Data on YH3 by Materials Project
YH3 crystallizes in the trigonal P-3c1 space group. The structure is three-dimensional. Y3+ is bonded in a 11-coordinate geometry to eleven H1- atoms. There are a spread of Y–H bond distances ranging from 2.14–2.50 Å. There are three inequivalent H1- sites. In the first H1- site, H1- is bonded in a trigonal planar geometry to three equivalent Y3+ atoms. In the second H1- site, H1- is bonded to four equivalent Y3+ atoms to form a mixture of distorted face, edge, and corner-sharing HY4 tetrahedra. In the third H1- site, H1- is bonded in a trigonal planar geometry to three equivalent Y3+ atoms.
36 MATERIALS SCIENCE↗
Materials Data on YH3 by Materials Project
YH3 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Y3+ is bonded in a 2-coordinate geometry to fourteen H1- atoms. There are a spread of Y–H bond distances ranging from 2.13–2.59 Å. There are two inequivalent H1- sites. In the first H1- site, H1- is bonded to six equivalent Y3+ atoms to form HY6 octahedra that share corners with twelve equivalent HY6 octahedra, corners with eighteen equivalent HY4 tetrahedra, edges with six equivalent HY6 octahedra, edges with six equivalent HY4 tetrahedra, faces with two equivalent HY6 octahedra, and faces with six equivalent HY4 tetrahedra. The corner-sharing octahedral tilt angles are 48°. In the second H1- site, H1- is bonded to four equivalent Y3+ atoms to form HY4 tetrahedra that share corners with nine equivalent HY6 octahedra, corners with nineteen equivalent HY4 tetrahedra, edges with three equivalent HY6 octahedra, edges with three equivalent HY4 tetrahedra, faces with three equivalent HY6 octahedra, and a faceface with one HY4 tetrahedra. The corner-sharing octahedra tilt angles range from 12–60°.
36 MATERIALS SCIENCE↗
Materials Data on YH2 by Materials Project
YH2 is Fluorite structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Y is bonded in a body-centered cubic geometry to eight equivalent H atoms. All Y–H bond lengths are 2.26 Å. H is bonded to four equivalent Y atoms to form a mixture of edge and corner-sharing HY4 tetrahedra.
36 MATERIALS SCIENCE↗
Materials Data on HI by Materials Project
HI1 is alpha carbon monoxide-like structured and crystallizes in the monoclinic C2/c space group. The structure is zero-dimensional and consists of sixteen hydriodic acid molecules. H1+ is bonded in a single-bond geometry to one I1- atom. The H–I bond length is 1.64 Å. I1- is bonded in a single-bond geometry to one H1+ atom.
36 MATERIALS SCIENCE↗
Materials Data on YH3 by Materials Project
YH3 crystallizes in the hexagonal P6_3cm space group. The structure is three-dimensional. Y3+ is bonded in a 11-coordinate geometry to eleven H1- atoms. There are a spread of Y–H bond distances ranging from 2.14–2.54 Å. There are four inequivalent H1- sites. In the first H1- site, H1- is bonded in a 4-coordinate geometry to four equivalent Y3+ atoms. In the second H1- site, H1- is bonded to four equivalent Y3+ atoms to form distorted corner-sharing HY4 tetrahedra. In the third H1- site, H1- is bonded in a trigonal planar geometry to three equivalent Y3+ atoms. In the fourth H1- site, H1- is bonded in a trigonal planar geometry to three equivalent Y3+ atoms.
36 MATERIALS SCIENCE↗
Proceedings of the Workshop for Applied Nuclear Data Activities WANDA 2022
On February 28 – March 4, 2022, the Nuclear Data Interagency Working Group (NDIAWG) hosted the 5-day virtual Workshop for Applied Nuclear Data (WANDA2022) to facilitate interagency collaboration on nuclear data for applications. This year’s focus was nuclear data for space applications, but also included photon reactions and transport, reactions on unstable nuclei, and data adjustment topics. The annual WANDA workshops are planned by the Nuclear Data Working Group (NDWG) with the goal of assembling users and producers of nuclear data to provide input to identify and prioritize nuclear data needs and to suggest solutions to address those needs. The workshop consisted of talks by agency program managers, six topic focused road mapping sessions and a review of NDIAWG-funded projects. More than 350 attendees represented national laboratories, universities, and federal agencies, as well as international organizations and industry. The proceedings presented herein summarize the workshop’s content, highlight important outcomes, and document attendees’ recommendations.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Lidar technology measurements and technology: Report of panel
Lidar is ready to make an important contribution to tropospheric chemistry research with a variety of spaceborne measurements that complement the measurements from passive instruments. Lidar can now be considered for near-term and far-term space missions dealing with a number of scientifically important issues in tropospheric chemistry. The evolution in the lidar missions from space are addressed and details of these missions are given. The laser availability for space missions based upon the technical data is assessed.
Browell, Edward V.↗