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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 541 records · Page 30
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Designing complex concentrated alloys with quantum machine learning and language modeling

Designing novel complex concentrated alloys (CCAs) is an essential topic in materials science. However, due to the complicated high-dimensional component-property relationship, tuning material properties by researchers’ experience is challenging, even when guided by physical or empirical rules. Here, we adopt quantum computing (QC) technology and machine learning models to provide a proof-of-concept application of QC in physical metallurgy. We propose a quantum support vector machine (QSVM) model to predict single-phase CCAs. We show that fine-tuned quantum kernels with entanglement deliver promising performance, with a maximum accuracy of 89.4%. The QSVM model is then used to identify 1,741 lightweight CCAs jointly with a new text-mining-based method. Meanwhile, we devise a controllable approach to study the effect of noise on model performance and find that the noise level needs to be minimized for high-performance QSVM models. Finally, this study provides a practical and general approach to designing CCAs based on quantum technologies.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Caltech Lab Experiments and the Insights They Provide Into Solar Corona Phenomena

A comprehensive overview of two decades of Caltech experiments relevant to solar corona physics is presented. The extent to which the experiments scale to the solar corona, the basic configurations and operation, and the importance of the magnetic force J × B common to all the experiments is discussed. Summaries are given of the various configurations used, the main observations, and interpretations of these observations, including new models developed to provide these interpretations. Topics include observations and explanations for flux rope self-collimation, axial flows along flux ropes, eruption of arched flux ropes, strapping magnetic fields that inhibit eruption, the torus instability, and effects such as X-ray emission of a kink-driven secondary Rayleigh-Taylor instability.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2016

Connecting radiative neutrino mass, neutron-antineutron oscillation, proton decay, and leptogenesis through dark matter

The scotogenic mechanism for radiative neutrino mass is generalized to include neutron-antineutron oscillation as well as proton decay. Dark matter is stabilized by extending the notion of lepton parity to matter parity. Leptogenesis is also a possible byproduct. In conclusion, this framework unifies the description of all these important topics in physics beyond the standard model of particle interactions.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2016

Theoretical Advanced Study Institute: 2014

The Theoretical Advanced Study Institute (TASI) was held at the University of Colorado, Boulder, during June 2-27, 2014. The topic was "Journeys through the Precision Frontier: Amplitudes for Colliders." The organizers were Professors Lance Dixon (SLAC) and Frank Petriello (Northwestern and Argonne). There were fifty-one students. Nineteen lecturers gave sixty seventy-five minute lectures. A Proceedings was published. This TASI was unique for its large emphasis on methods for calculating amplitudes. This was embedded in a program describing recent theoretical and phenomenological developments in particle physics. Topics included introductions to the Standard Model, to QCD (both in a collider context and on the lattice), effective field theories, Higgs physics, neutrino interactions, an introduction to experimental techniques, and cosmology.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

Sample EP Flow Analysis of Severely Damaged Networks

These are slides for a presentation at the working group meeting of the WESC SREMP Software Product Integration Team on sample EP flow analysis of severely damaged networks. The following topics are covered: ERCOT EP Transmission Model; Zoomed in to Houston and Overlaying StreetAtlas; EMPACT Solve/Dispatch/Shedding Options; QACS BaseCase Power Flow Solution; 3 Substation Contingency; Gen. & Load/100 Optimal Dispatch; Dispatch Results; Shed Load for Low V; Network Damage Summary; Estimated Service Areas (Potential); Estimated Outage Areas (potential).

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2019

ERL Timing and optimized CBETA models

This project develops a method of finding instrument settings that minimize the power load on accelerating radio-frequency (RF) cavities in an energy recovery linac (ERL). A general symmetry theory, which has been developed in detail and was previously tested in simple ERL models, will be used to optimize more detailed models of the Cor nell Brookhaven ERL Test Accelerator (CBETA). CBETA specifications are detailed in Fig. 1. Due to the high overlap with previous work, this report briefly summarizes the relevant outcomes of older ERL symmetry models; however, the reader is encouraged to consult for a more comprehensive coverage of these topics. This report will focus primarily on extensions of symmetry modeling toward more complex systems, including multi particle beams or CBETA-specific cavity tracking.

43 PARTICLE ACCELERATORS↗
DOE OSTI2019

Directly probing spin fluctuations in quantum spin liquids with X-ray Free Electron Lasers

Quantum Spin Liquids (QSLs) represent a class of Quantum Magnets where the ground state is understood to be a non-trivial superposition of many states, connected by local spin fluctuations. This complex entanglement, which is the defining feature of a QSL phase, does not couple directly to experimental probes, making the detection of candidate QSL materials difficult. With this proposal we intended to test the following hypothesis: “Is it possible to directly couple to the quantum spin fluctuations typical of QSLs by combining standard spectroscopic techniques with the high temporal resolution of X-ray Free Electron Lasers (XFELs)?” This argument relied on the simple observation that quantum spin fluctuations belong to the same femtosecond time scale typical of XFEL pulses. At the end of the project, this question remains unanswered. However, our work as helped shed some light on the effect of impurities on the theoretical stability of QSL phases in a special class of materials described by the so-called Transverse Field Ising Model on the pyrochlore lattice. This topic is of great relevance to the community today, given that any experiment must deal with the ever-present deviations of each sample from its ideal atomic composition and crystalline structure.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
NASA NTRS1973

Systems concepts: Lectures on contemporary approaches to systems.

Collection of papers dealing with the application of systems concepts to a wide range of disciplines. The topics include systems definitions and designs, models for systems engineering, the evolution of the JPL, systems concepts in lunar and planetary projects, civil systems projects, and Apollo program evaluation. Individual items are announced in this issue.

Miles, R. F., Jr.↗
NASA NTRS1973

Techniques for shuttle trajectory optimization

The application of recently developed function-space Davidon-type techniques to the shuttle ascent trajectory optimization problem is discussed along with an investigation of the recently developed PRAXIS algorithm for parameter optimization. At the outset of this analysis, the major deficiency of the function-space algorithms was their potential storage problems. Since most previous analyses of the methods were with relatively low-dimension problems, no storage problems were encountered. However, in shuttle trajectory optimization, storage is a problem, and this problem was handled efficiently. Topics discussed include: the shuttle ascent model and the development of the particular optimization equations; the function-space algorithms; the operation of the algorithm and typical simulations; variable final-time problem considerations; and a modification of Powell's algorithm.

Edge, E. R.↗
NASA NTRS1975

Program to Optimize Simulated Trajectories (POST). Volume 1: Formulation manual

A general purpose FORTRAN program for simulating and optimizing point mass trajectories (POST) of aerospace vehicles is described. The equations and the numerical techniques used in the program are documented. Topics discussed include: coordinate systems, planet model, trajectory simulation, auxiliary calculations, and targeting and optimization.

Brauer, G. L.↗
NASA NTRS1978

OSO-8 X-ray spectra of clusters of galaxies. 2: Discussion

X-ray spectral parameters obtained from 2 to 20 keV OSO-8 data on X-ray clusters and optical cluster properties were examined to obtain information for restricting models for hot intracluster gas structures. Topics discussed include the radius of the X-ray core in relation to the galaxy core radius, the viral mass of hotter clusters, and galaxy density and optical central cluster properties. A population of cool, dim X-ray clusters which have not been observed is predicted. The iron abundance determinations recently quoted for intracluster gas are uncertain by 50 to greater than 100 percent from this nonstatistical cause alone.

Smith, B. W.↗
NASA NTRS1977

Dynamical implications of the petrology and distribution of impact melt rocks

Petrographic and structural relations of rocks resulting from melting of target materials during impact indicate constraints that can be applied to theoretical models and experimental production of craters. Topics discussed in this context include the motion of shock melted material, the mixing of melts, the energies required for heating and melting the necessary volumes of target rocks, diameter to depth ratios, and the formation of structural modifications. The motion of shock melted material involves ejection of some of the lowermost parts of the target, incorporation of distant fragmental material, outward flow, settling into cracks after breccia formation, and completion in a short time span. Melts must be completed within tens of seconds to a couple of minutes after impact.

Phinney, W. C.↗
NASA NTRS1979

Earth-Moon system: Dynamics and parameter estimation

The following topics are discussed: (1) the Unified Model of Lunar Translation/Rotation (UMLTR); (2) the effect of figure-figure interactions on lunar physical librations; (3) the effect of translational-rotational coupling on the lunar orbit; and(4) an error analysis for estimating lunar inertias from LURE (Lunar Laser Ranging Experiment) data.

Breedlove, W. J., Jr.↗
NASA NTRS1985

Silicon material and JPL Web Team

Silicon material activities are described. Topics discussed include: fluidized bed technology, model predictions (reaction kinetics and grid design parameters), seed-particle cleaning procedure, runaway nucleation, thermal analysis of dendritic ribbons, and residual stress in dendritic ribbons.

Lutwack, R.↗
NASA NTRS1986

Cellular solidification of transparent monotectics

Understanding how liquid phase particles are engulfed or pushed during freezing of a monotectic is addressed. The additional complication is that the solid-liquid interface is nonplanar due to constitutional undercooling. Some evidence of particle pushing where the particles are the liquid phase of the montectic was already observed. Cellular freezing of the succinonitrile-glycerol system also occurred. Only a few compositions were tested at that time. The starting materials were not especially pure so that cellular interface observed was likely due to the presence of unkown impurities, the major portion of which was water. Topics addressed include: the effort of modeling the particle pushing process using the computer, establishing an apparatus for the determination of phase diagrams, and the measurement of the temperature gradients with a specimen which will solidify on the temperature gradient microscope stage.

Kaulker, W. F.↗
NASA NTRS1990

Reports on block rotations, fault domains and crustal deformation

Studies of block rotations, fault domains and crustal deformation in the western United States, Israel, and China are discussed. Topics include a three-dimensional model of crustal fracture by distributed fault sets, distributed deformation and block rotation in 3D, stress field rotation, and multiple strike slip fault sets.

Nur, Amos↗
NASA NTRS1990

South Pacific convergence zone and global-scale circulations

Current research is focused on four topics. First, the GLA Global Circulation Model (GCM) is used for a series of experiments to examine the relationship between tropical heating and subtropical westerly wind maxima. Second, barotropic and baroclinic energy mechanisms associated with summertime subtropical wind maxima in the Southern Hemisphere is studied. Third, tropical/extratropical interactions in the Southern Hemisphere summer circulation is studied; the focus is on the importance of the 30 to 60 day tropical oscillation as a cause of enhancing the subtropical westerly winds. Finally, a study of precipitation efficiency in the tropics, comparing mean monthly distributions of precipitation over a three-year period to precipitable water and moisture convergency is being conducted.

Vincent, Dayton G.↗