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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 1,171 records · Page 65
All sourcesNASA NTRSDOE OSTI
NASA NTRS2006

On the Observed Changes in Upper Stratospheric and Mesospheric Temperatures from UARS HALOE

Temperature versus pressure or T(p) time series from the Halogen Occultation Experiment (HALOE) on the Upper Atmosphere Research Satellite (UARS) have been extended and re-analyzed for the period of 1991-2005 and for the upper stratosphere and mesosphere in 10-degree wide latitude zones from 60S to 60N. Even though sampling from a solar occultation experiment is somewhat limited, it is shown to be quite adequate for developing both the seasonal and longer-term variations in T(p). Multiple linear regression (MLR) techniques were used in the re-analyses for the seasonal and the significant interannual, solar cycle (SC-like or decadal-scale), and linear trend terms. A simple SC-like term of 11-yr period was fitted to the time series residuals after accounting for the seasonal and interannual terms. Highly significant SC-like responses were found for both the upper mesosphere and the upper stratosphere. The phases of these SC-like terms were checked for their continuity with latitude and pressure-altitude, and in almost all cases they are directly in-phase with that of standard proxies for the solar flux variations. The analyzed, max minus min, responses at low latitudes are of order 1 K, while at middle latitudes they are as large as 3 K in the upper mesosphere. Highly significant, linear cooling trends were found at middle latitudes of the middle to upper mesosphere (about -2 K/decade), at tropical latitudes of the middle mesosphere (about -1 K/decade), and at 2 hPa (or order -1 K/decade).

Remsberg, Ellis E.↗
NASA NTRS2010

Improvement in the Shape Memory Response of Ti50.5Ni24.5Pd25 High-Temperature Shape Memory Alloy with Scandium Microalloying

A Ti(50.5)Ni(24.5)Pd25 high-temperature shape memory alloy (HTSMA) is microalloyed with 0.5 at. pct scandium (Sc) to enhance its shape-memory characteristics, in particular, dimensional stability under repeated thermomechanical cycles. For both Ti(50.5)Ni(24.5)Pd25 and the Sc-alloyed material, differential scanning calorimetry is conducted for multiple cycles to characterize cyclic stability of the transformation temperatures. The microstructure is evaluated using electron microscopy, X-ray diffractometry, and wavelength dispersive spectroscopy. Isobaric thermal cycling experiments are used to determine transformation temperatures, dimensional stability, and work output as a function of stress. The Sc-doped alloy displays more stable shape memory response with smaller irrecoverable strain and narrower thermal hysteresis than the baseline ternary alloy. This improvement in performance is attributed to the solid solution hardening effect of Sc.

Atli, K. C.↗
NASA NTRS2015

Airspace Safety Threshold Study: NAS-Wide Encounter Rate Evaluation Using Historical Radar Data and ACES

Realization of the expected proliferation of Unmanned Aircraft System (UAS) operations in the National Airspace System (NAS) depends on the development and validation of performance standards for UAS Detect and Avoid (DAA) Systems. The RTCA Special Committee 228 (SC-228) is charged with leading the development of draft Minimum Operational Performance Standards (MOPS) for UAS DAA Systems. NASA, as a participating member of RTCA SC-228 is committed to supporting the development and validation of draft requirements as well as the safety substantiation and end-to-end assessment of DAA system performance. With regard to the safety aspect being studied by the SC-228 DAA Safety sub-group, NASA has conducted a study using the ACES (Airspace Concept Evaluation System) simulation capability to determine: 1) the rate at which IFR aircraft encounter other IFR and VFR aircraft, and 2) the rate at which UAS aircraft encounter VFR aircraft as well as the corresponding encounter geometries. Five different separation thresholds were used (two for encounter and one each for well-clear, near mid-air collision, and closest point of approach). The results will be used by the SC-228 DAA Safety sub-group to inform decisions about the safety aspect of UAS DAA systems and future requirements development and validation efforts.

encounter geometry↗
NASA NTRS2021

NASA SpaceCube Edge TPU SmallSat Card for Autonomous Operations and Onboard Science-Data Analysis

Using state-of-the-art artificial intelligence (AI)frameworks onboard spacecraft is challenging because common spacecraft processors cannot provide comparable performance to datacenters with server-grade CPUs and GPUs available for terrestrial applications and advanced deep-learning networks. This limitation makes small, lo w-p o we r AI microchip architectures, such as the Google Coral Edge Tensor Processing Unit (TPU), attractive for space missions where the application-specific design enables both high-performance and power-efficient computing for AI applications. To address these challenging considerations for space deployment, this research introduces the design and capabilities of a CubeSat-sized Edge TPU-based co-processor card, known as the SpaceCube Low-power Ed g e Artificial Intelligence Resilient Node (SC-LEARN). This design conforms to NASA’s CubeSat Card Specification (CS2) for integration into next-generation SmallSat and CubeSat systems. This paper describes the overarching architecture and design of the SC-LEARN, as well as, the supporting test card designed for rapid prototyping and evaluation. The SC-LEARN was developed with three operational modes: (1) a high-performance parallel-processing mode,(2)a fault-tolerant mode for onboard resilience, and (3) a power-saving mode with cold spares. Importantly, this research also elaborates on both training and quantization of Tensor Flow models for the SC-LEARN for use onboard with representative, open-source datasets. Lastly, we describe future research plans, including radiation-beam testing and flight demonstration.

Advanced avionics↗
DOE OSTI2021

THERMAL ANALYSIS OF THE RHIC ARC DIPOLE MAGNET COLD MASS WITH THE EIC BEAM SCREEN

The EIC will make use of the existing RHIC storage rings with their superconducting (SC) magnet arcs. A stain-less-steel beam screen with co-laminated copper and a thin amorphous carbon (aC) film on the inner surface will be installed in the beam pipe of the SC magnets. The copper will reduce the beam-induced resistive-wall (RW) heating from operation with the higher intensity EIC beams, that if not addressed would make the magnets quench. Limiting the RW heating is also important to achieve an adequately low vacuum level. The aC coating will reduce secondary electron yield which could also cause heating and limit in-tensity. Among all the RHIC SC magnets, the arc dipoles present the biggest challenge to the design and installation of beam screens. The arc dipoles, which make up for 78% (2.5 km) length of all SC magnets in RHIC, expect the larg-est RW heating due to their smallest aperture. These mag-nets are also the longest (9.45 m each), thus experiencing the largest temperature rise over their length, and have a large sagitta (48.5 mm) that increases the difficulty to in-stall the beam screen in place. This paper presents a de-tailed thermal analysis of the magnet-screen system.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

Phononic bus for coherent interfaces between a superconducting quantum processor, spin memory, and photonic quantum networks

A hybrid quantum system performs high-fidelity quantum state transduction between a superconducting (SC) microwave qubit and the ground state spin system of a solid-state artificial atom. This transduction is mediated via an acoustic bus connected by piezoelectric transducers to the SC microwave qubit. For SC circuit qubits and diamond silicon vacancy centers in an optimized phononic cavity, the system can achieve quantum state transduction with fidelity exceeding 99% at a MHz-scale bandwidth. By combining the complementary strengths of SC circuit quantum computing and artificial atoms, the hybrid quantum system provides high-fidelity qubit gates with long-lived quantum memory, high-fidelity measurement, large qubit number, reconfigurable qubit connectivity, and high-fidelity state and gate teleportation through optical quantum networks.

Englund, Dirk Robert↗
DOE OSTI2024

Multi-resonant switched capacitor power converter architecture

A switched-capacitor (SC) network in an SC converter is controlled to operate at varying resonant modes to achieve high conversion ratio efficiency, at a low circuit component count. These power converters are suited to numerous application areas including improving energy efficiency of data centers. A family of resonant switched capacitor (SC) converters with multiple operating phases are presented “Multi-Resonant SC Converters”. Described in detail are an 8-to-1 Multi-Resonant-Doubler (MRD) converter and a 6-to-1 Cascaded Series-Parallel (CaSP). The topology of these converters make them amenable to combining like units in parallel toward reaching higher power levels.

Ye, Zichao↗
DOE OSTI2021

Inverse Biot–Savart Optimization for Superconducting Accelerator Magnets

Superconducting (SC) magnets for accelerator concepts are often synthesized by numerically optimizing magnetic field waveforms, a process that requires a subsequent solution of a constrained inverse problem to identify suitable SC magnet windings. When the desired field distribution is intuitive, the inverse process is facilitated by seeding preconceived coil distributions into design optimization methods for refinement. With more complex magnetic field distributions, an initial design may be unknown, and topology optimization tools are required to synthesize current distributions without a priori guidance from a subject matter expert. In this work, we develop a constrained inverse Biot-Savart topology optimization methodology that synthesizes optimal distributions of current density in racetrack-like SC coils. The problem structure is exploited through a computationally efficient quadratic programming formulation, and the method is applied to recently published magnetic field waveforms for a recirculating proton phase shifter, a proton therapy gantry, and dipole magnets with sharp field transitions. The method and results herein identify novel winding configurations that can help magnet designers bring accelerator concepts to fruition.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2020

Materials Data on ScH3(CO2)3 by Materials Project

Sc(OOCH)3 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Sc3+ sites. In the first Sc3+ site, Sc3+ is bonded in an octahedral geometry to six O2- atoms. There are a spread of Sc–O bond distances ranging from 2.09–2.13 Å. In the second Sc3+ site, Sc3+ is bonded in an octahedral geometry to six O2- atoms. There are two shorter (2.10 Å) and four longer (2.12 Å) Sc–O bond lengths. There are three inequivalent C2+ sites. In the first C2+ site, C2+ is bonded in a trigonal planar geometry to one H1+ and two O2- atoms. The C–H bond length is 1.10 Å. Both C–O bond lengths are 1.27 Å. In the second C2+ site, C2+ is bonded in a trigonal planar geometry to one H1+ and two O2- atoms. The C–H bond length is 1.11 Å. There is one shorter (1.26 Å) and one longer (1.27 Å) C–O bond length. In the third C2+ site, C2+ is bonded in a trigonal planar geometry to one H1+ and two O2- atoms. The C–H bond length is 1.11 Å. There is one shorter (1.26 Å) and one longer (1.27 Å) C–O bond length. There are three inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one C2+ atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one C2+ atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one C2+ atom. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Sc3+ and one C2+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Sc3+ and one C2+ atom. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Sc3+ and one C2+ atom. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one Sc3+ and one C2+ atom. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to one Sc3+ and one C2+ atom. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to one Sc3+ and one C2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CeScSi by Materials Project

CeScSi crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ce is bonded in a 5-coordinate geometry to five equivalent Si atoms. There are four shorter (3.13 Å) and one longer (3.15 Å) Ce–Si bond lengths. Sc is bonded in a distorted square co-planar geometry to four equivalent Si atoms. All Sc–Si bond lengths are 2.88 Å. Si is bonded in a 9-coordinate geometry to five equivalent Ce and four equivalent Sc atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ScCo3C by Materials Project

ScCo3C is (Cubic) Perovskite structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Sc is bonded to twelve equivalent Co atoms to form ScCo12 cuboctahedra that share corners with twelve equivalent ScCo12 cuboctahedra, faces with six equivalent ScCo12 cuboctahedra, and faces with eight equivalent CCo6 octahedra. All Sc–Co bond lengths are 2.70 Å. Co is bonded in a distorted linear geometry to four equivalent Sc and two equivalent C atoms. Both Co–C bond lengths are 1.91 Å. C is bonded to six equivalent Co atoms to form CCo6 octahedra that share corners with six equivalent CCo6 octahedra and faces with eight equivalent ScCo12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sc2BC2 by Materials Project

Sc2BC2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Sc+2.50+ is bonded to five equivalent C4- atoms to form a mixture of corner and edge-sharing ScC5 square pyramids. There are one shorter (2.23 Å) and four longer (2.37 Å) Sc–C bond lengths. B3+ is bonded in a linear geometry to two equivalent C4- atoms. Both B–C bond lengths are 1.48 Å. C4- is bonded to five equivalent Sc+2.50+ and one B3+ atom to form a mixture of corner and edge-sharing CSc5B octahedra. The corner-sharing octahedra tilt angles range from 0–7°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sc2AlSi2 by Materials Project

AlSc2Si2 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. Sc+2.50+ is bonded in a distorted hexagonal planar geometry to six equivalent Si4- atoms. There are two shorter (2.73 Å) and four longer (2.84 Å) Sc–Si bond lengths. Al3+ is bonded in a square co-planar geometry to four equivalent Si4- atoms. All Al–Si bond lengths are 2.61 Å. Si4- is bonded in a 9-coordinate geometry to six equivalent Sc+2.50+, two equivalent Al3+, and one Si4- atom. The Si–Si bond length is 2.36 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ScRh3C by Materials Project

ScRh3C is (Cubic) Perovskite structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Sc is bonded to twelve equivalent Rh atoms to form ScRh12 cuboctahedra that share corners with twelve equivalent ScRh12 cuboctahedra, faces with six equivalent ScRh12 cuboctahedra, and faces with eight equivalent CRh6 octahedra. All Sc–Rh bond lengths are 2.90 Å. Rh is bonded to four equivalent Sc and two equivalent C atoms to form a mixture of distorted edge, face, and corner-sharing RhSc4C2 octahedra. The corner-sharing octahedra tilt angles range from 0–60°. Both Rh–C bond lengths are 2.05 Å. C is bonded to six equivalent Rh atoms to form CRh6 octahedra that share corners with six equivalent CRh6 octahedra and faces with eight equivalent ScRh12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ScAlAu2 by Materials Project

ScAu2Al is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Sc is bonded in a body-centered cubic geometry to eight equivalent Au atoms. All Sc–Au bond lengths are 2.86 Å. Au is bonded in a body-centered cubic geometry to four equivalent Sc and four equivalent Al atoms. All Au–Al bond lengths are 2.86 Å. Al is bonded in a body-centered cubic geometry to eight equivalent Au atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ScAlNi2 by Materials Project

AlNi2Sc is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Sc is bonded in a body-centered cubic geometry to eight equivalent Ni atoms. All Sc–Ni bond lengths are 2.62 Å. Ni is bonded in a body-centered cubic geometry to four equivalent Sc and four equivalent Al atoms. All Ni–Al bond lengths are 2.62 Å. Al is bonded in a distorted body-centered cubic geometry to eight equivalent Ni atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ScAg by Materials Project

AgSc is Tetraauricupride structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Sc is bonded in a body-centered cubic geometry to eight equivalent Ag atoms. All Sc–Ag bond lengths are 2.98 Å. Ag is bonded in a body-centered cubic geometry to eight equivalent Sc atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ScAu by Materials Project

AuSc is Tetraauricupride structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Sc is bonded in a body-centered cubic geometry to eight equivalent Au atoms. All Sc–Au bond lengths are 2.96 Å. Au is bonded in a body-centered cubic geometry to eight equivalent Sc atoms.

36 MATERIALS SCIENCE↗