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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 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Search for the e + e − → η b ( 1 S ) ω and e + e − → χ b 0 ( 1 P ) ω processes at s = 10.745 GeV

We search for the e + e − → η b ( 1 S ) ω and e + e − → χ b 0 ( 1 P ) ω processes at a center-of-mass energy of 10.745 GeV, which is close to the peak of the ϒ ( 10753 ) state. We use data collected by the Belle II experiment during a special run, corresponding to an integrated luminosity of 9.8 fb − 1 . We reconstruct ω → π + π − π 0 decays and use the ω meson’s recoil mass to search for the signals. We do not find evidence for either process, and set upper limits on the corresponding Born-level cross sections of 2.5 pb and 7.8 pb, respectively, at the 90% confidence level. The χ b 0 ( 1 P ) ω limit is the result of a combination of this analysis and a previous search using full reconstruction. Published by the American Physical Society 2024

Astronomy & Astrophysics↗
DOE OSTI2024

Mass gaps of a Z 3 gauge theory with three fermion flavors in 1 + 1 dimensions

We consider a Z 3 gauge theory coupled to three degenerate massive flavors of fermions, which we term Quantum Z(3) Dynamics, QZD. The spectrum can be computed in 1 + 1 dimensions using tensor networks. In weak coupling the spectrum is that of the expected mesons and baryons, although the corrections in weak coupling are nontrivial, analogous to those of nonrelativistic QED in 1 + 1 dimensions. In strong coupling, besides the usual baryon, the singlet meson is a baryon-antibaryon state. For two special values of the coupling constant, the lightest baryon is degenerate with the lightest octet meson, and the lightest singlet meson, respectively. Published by the American Physical Society 2024

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2020

SU(1,1) Echoes for Breathers in Quantum Gases

Though the celebrated spin echoes have been widely used to reverse quantum dynamics, they are not applicable to systems whose constituents are beyond the control of the su(2) algebra. In this work, we design echoes to reverse quantum dynamics of breathers in three-dimensional unitary fermions and two-dimensional bosons and fermions with contact interactions, which are governed by an underlying su(1, 1) algebra. Geometrically, SU(1, 1) echoes produce closed trajectories on a single or multiple Poincaré disks and thus could recover any initial states without changing the sign of the Hamiltonian. In particular, the initial shape of a breather determines the superposition of trajectories on multiple Poincaré disks and whether the revival time has period multiplication. Our work provides physicists with a recipe to tailor collective excitations of interacting many-body systems.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2024

R ( 3780 ) Resonance Interpreted as the 1 D 1 3 -Wave Dominant State of Charmonium from Precise Measurements of the Cross Section of e + e − → Hadrons

We report the precise measurements of the cross section of e + e − → hadrons at center-of-mass energies from 3.645 to 3.871 GeV. We thereby perform the most precise study of the cross sections and find a complex system composed of three resonances of R ( 3760 ) , R ( 3780 ) , and R ( 3810 ) . For the first time, we measure the R ( 3810 ) electronic width to be ( 19.4 ± 7.4 ± 12.1 ) eV . For the R ( 3760 ) resonance, we measure the mass to be ( 3751.9 ± 3.8 ± 2.8 ) MeV / c 2 , the total width to be ( 32.8 ± 5.8 ± 8.7 ) MeV , and the electronic width to be ( 184 ± 75 ± 86 ) eV . For the R ( 3780 ) resonance, we measure its mass to be ( 3778.7 ± 0.5 ± 0.3 ) MeV / c 2 , total width to be ( 20.3 ± 0.8 ± 1.7 ) MeV , and electronic width to be ( 265 ± 67 ± 83 ) eV . Forty-seven years ago, the ψ ( 3770 ) resonance was discovered, and was subsequently interpreted as the 1 D 1 3 -wave dominant state of charmonium. However, our analysis of the total-hadron cross sections indicates that the ψ ( 3770 ) is not a single state, but a complex system composed of the R ( 3760 ) , R ( 3780 ) , and R ( 3810 ) resonances. Among these, we interpret the R ( 3780 ) is a resonance dominated by the 1 D 1 3 charmonium state. Published by the American Physical Society 2024

Ablikim, M.↗
DOE OSTI2025

Quantum-enhanced distributed phase sensing with a truncated SU(1,1) interferometer

In recent years, distributed quantum sensing has gained interest for a range of applications requiring networks of sensors, from global-scale clock synchronization to high energy physics. In particular, a network of entangled sensors can improve not only the sensitivity beyond the shot noise limit, but also enable a Heisenberg scaling with the number of sensors. Here, using bright entangled twin beams, we theoretically and experimentally demonstrate the detection of a linear combination of two distributed phases beyond the shot noise limit with a truncated SU(1,1) interferometer. Specifically, we show a quantum noise reduction of 1.7 ± 0.3 dB below what is possible with the corresponding classical configuration. Additionally, we theoretically extend the use of a truncated SU(1,1) interferometer to a multi-phase-distributed sensing scheme that leverages entanglement as a resource to achieve a quantum improvement in the scaling with the number of sensors in the network. Our results pave the way for developing quantum-enhanced sensor networks that can achieve an entanglement-enhanced sensitivity.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2021

Dual-Wavelength Time-Resolved Photoluminescence Study of CdSe x Te 1-x Surface Passivation via Mg y Zn 1-y O and Al 2 O 3

Voltage loss is currently one of the biggest challenges facing cadmium telluride (CdTe) based photovoltaics. Determining the location(s) of major voltage loss within the device stack (e.g., front/back interface, grain boundaries) is therefore of primary interest. Here, we present a custom-built time-resolved photoluminescence system with two excitation wavelengths - 670 (standard) and 405 nm - to probe the device stack at depths of approximately 130 and 35 nm, respectively; their comparison helps differentiate interface and bulk contributions to carrier lifetime. We apply this system to examine the passivation effect of two significant recent advances in CdTe: the incorporation of Se to form graded CdSe x Te 1-x and the replacement of CdS with Mg y Zn 1-y O. It is found that x = 0.2 Se is required to obtain lifetime improvements, primarily in the bulk. Additionally, evidence for trapping at the Mg y Zn 1-y O/CdSe x Te 1-x interface was observed. Furthermore, this indicates further work is required to sufficiently passivate the front interface.

CdSeTe↗
DOE OSTI2020

A New Configuration of Paralleled Modular ANPC Multilevel Converter Controlled by an Improved Modulation Method for 1 MHz, 1 MW EV Charger

In this work, a new configuration of the modular multilevel converter (MLC) based on the parallel connection of three-level active-neutral-point-clamped (3L-ANPC) cells as well as its improved modulation method is proposed for 1 MHz, 1 MW electric vehicle (EV) megacharger. In the proposed paralleled modular ANPC-MLC, only six high-frequency silicon carbide (SiC) power switches operating at 333 kHz are required to generate 1 MHz switching frequency spectrum. Moreover, the operating voltage of all power devices is halved, the magnitude of the first switching frequency harmonic cluster is decreased by the factor of five, and the load current is equally distributed between the 3L-ANPC legs by employing the proposed improved modulation method. Hence, the modularity, efficiency, and power density of the proposed converter are notably increased, whereas the value of passive components and the overall switching loss are remarkably decreased. In addition, an optimized design of the one 3L-ANPC cell of the proposed paralleled modular ANPC-MLC for 1 MHz, 1MW EV megacharger using Ansys SIwave, Icepak, and Q3D finite element method platforms is presented and analyzed in detail. The provided experimental results of the down-scaled setup verify the feasibility and viability of the proposed configuration as well as its improved switching pattern.

42 ENGINEERING↗
DOE OSTI2026

Terrestrial laser scanning data (Levels 0 and 1) for Pasoh, Malaysia, Sep 2024

This data package contains data from terrestrial laser scanning (TLS) at the Pasoh Forest Reserve, Malaysia. The Pasoh Forest Reserve is a facility of the Forest Research Institute Malaysia, and contains evergreen lowland dipterocarp forest. The Next-Generation Ecosystem Experiments Tropics (NGEE-Tropics) study areas at Pasoh were established to study how different species respond to climatic variation and soil water availability. Two study areas were chosen representing different topography and species. The TLS data archived here were collected to provide detailed, three-dimensional information about forest structure. Specifically, data were collected to allow tree-level characterization of woody structure and leaf area for 12 focal trees with FloraPulse and sap flux sensors, facilitating estimation of woody biomass and leaf area to allow upscaling of water content and transpiration data to the tree-level. Scan positions were not selected to provide consistent data for non-focal trees with the study areas. This data package contains the following data: - High-level files document further details of the campaign and data package: 1_CampaignSummary.csv provides details about the campaign and study site, 2_ScanAreasDetail.csv provides details about each separate scan area (groups of scans post-processed into a single point cloud), 3_TerrestrialLidarSensor.csv provides further technical details about the Riegl VZ-400i TLS sensor, TLS_CSV_dd.csv is a CSV Data Dictionary providing information about the fields in CSV files following the ESS-DIVE CSV File Formatting Guidelines Reporting Format, TLS_flmd.csv is a File Level Metadata file providing information about each file in the data package following the ESS-DIVE File Level Metadata Reporting Format, and README.txt is a text file describing the overall project and file structure. - Level 0 data are the raw data (.PROJ folders) as recorded by the Riegl VZ-400i TLS instrument before scan co-registration and post-processing with the Riegl's proprietary RiSCAN PRO software, which requires a license. - Level 1 data contain post-processed, co-registered data from each scan area. The "PointClouds" folder for each scan area contains a .las file with 1 cm resolution point cloud data exported from RiSCAN PRO. These are the main files likely to be of interest to most users and can be further processed with any software capable of manipulating .las files (e.g. Python, R CloudCompare). The "Project Information" folder contains log files from post-processing in RiSCAN PRO that may be of interest to users who want to see detailed records of post-processing, including all PDF reports generated by RiSCAN PRO. The "ScanPositions" folder contains information about the final position of all TLS scans, after post-processing, in multiple formats. The file ScanPositions_*.csv provides final geo-referenced scan positions, and the file SOP_backup_*.csv can be used in RiSCAN PRO to restore the co-registered scan positions if users wish to re-process raw data (Level 0 .PROJ folders) with RiSCAN PRO software (e.g., subsample to a different resolution, exclude a certain scan position, or apply different filters on reflectance or deviation values) without redoing time-consuming co-registration steps.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2026

Terrestrial laser scanning data (Levels 0 and 1) from Urban Biogeochemistry Pilot Project sites, Knoxville, Tennessee, Jul 2024 - Jul 2025

This data package contains data from terrestrial laser scanning (TLS) at five urban park sites in Knoxville, Tennessee, USA. All parks include open-grown and/or closed-canopy trees and mixed nearby land use. These study sites were established as part of the Urban Biogeochemistry Pilot Project, which has an overall goal of better understanding how hydrobiogeochemical cycling is altered within the human environment. These five sites represent a gradient of urbanization, and were instrumented to understand hydrological and biogeochemical cycling (e.g., soil moisture, soil physical properties and biogeochemistry, tree transpiration, species type). The TLS data archived here were collected to provide detailed, three-dimensional information about forest structure. Specifically, data were collected to allow tree- and stand-level characterization of woody structure and leaf area. TLS scans were placed to capture the area around trees with sap flow sensors, and as much of a 50 m radius area around the meteorological station as possible given site property limits. Derived products will allow upscaling of water content and transpiration data. This data package contains the following data: - High-level files document further details of the campaign and data package: 1_CampaignSummary.csv provides details about the campaign and study site, 2_ScanAreasDetail.csv provides details about each separate scan area (groups of scans post-processed into a single point cloud), 3_TerrestrialLidarSensor.csv provides further technical details about the Riegl VZ-400i TLS sensor, TLS_CSV_dd.csv is a CSV Data Dictionary providing information about the fields in CSV files following the ESS-DIVE CSV File Formatting Guidelines Reporting Format, TLS_flmd.csv is a File Level Metadata file providing information about each file in the data package following the ESS-DIVE File Level Metadata Reporting Format, and README.txt is a text file describing the overall project and file structure. - Level 0 data are the raw data (.PROJ folders) as recorded by the Riegl VZ-400i TLS instrument before scan co-registration and post-processing with the Riegl's proprietary RiSCAN PRO software, which requires a license. - Level 1 data contain post-processed, co-registered data from each scan area. The "PointClouds" folder for each scan area contains a .las file with 1 cm resolution point cloud data exported from RiSCAN PRO. These are the main files likely to be of interest to most users and can be further processed with any software capable of manipulating .las files (e.g. Python, R CloudCompare). The "Project Information" folder contains log files from post-processing in RiSCAN PRO that may be of interest to users who want to see detailed records of post-processing, including all PDF reports generated by RiSCAN PRO. The "ScanPositions" folder contains information about the final position of all TLS scans, after post-processing, in multiple formats. The file ScanPositions_*.csv provides final geo-referenced scan positions, and the file SOP_backup_*.csv can be used in RiSCAN PRO to restore the co-registered scan positions if users wish to re-process raw data (Level 0 .PROJ folders) with RiSCAN PRO software (e.g., subsample to a different resolution, exclude a certain scan position, or apply different filters on reflectance or deviation values) without redoing time-consuming co-registration steps.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

Production of 1,3-Butadiene from Renewable Feedstocks Ethanol and 1,3-Butanediol - CRADA 560 (Final Report)

1,3-butadiene is a commodity chemical currently produced from petroleum sources. Producing 1,3-butadiene from renewable resources will contribute to decarbonization, provide new green jobs, and reduce our dependance on oil. Development of multifunctional catalysts that are active, selective, and stable for this reaction has been an area of research and development. This effort reported here builds on our prior work for the 1-step conversion of ethanol to butadiene. The goal of the additional scope performed here was to accelerate the commercial deployment of sustainable butadiene production. We demonstrated that the PNNL Ag-based catalyst is significantly more active than the WWII-era catalyst when operated under the same conditions. A butadiene selectivity of 68% was obtained at 64% conversion for the production of butadiene from ethanol. It was found that ethanol feedstock is preferred over 1,3-butanediol feedstock to produce butadiene due to higher yield resulting in lower butadiene selling price (i.e., $\$$0.4-1.7/ lb). Production of 3.0 Liter of butadiene solution in hexane containing 100 grams of butadiene was achieved and delivered to Bridgestone for producing a butadiene-derived test piece.

09 BIOMASS FUELS↗
DOE OSTI2022

ZnO-Au x Cu 1-x Alloy and ZnO-Au x Al 1-x Alloy Vertically Aligned Nanocomposites for Low-Loss Plasmonic Metamaterials

Hyperbolic metamaterials are a class of materials exhibiting anisotropic dielectric function owing to the morphology of the nanostructures. In these structures, one direction behaves as a metal, and the orthogonal direction behaves as a dielectric material. Applications include subdiffraction imaging and hyperlenses. However, key limiting factors include energy losses of noble metals and challenging fabrication methods. In this work, self-assembled plasmonic metamaterials consisting of anisotropic nanoalloy pillars embedded into the ZnO matrix are developed using a seed-layer approach. Alloys of Au x Al 1-x or Au x Cu 1-x are explored due to their lower losses and higher stability. Optical and microstructural properties were explored. The ZnO-Au x Cu 1-x system demonstrated excellent epitaxial quality and optical properties compared with the ZnO-Au x Al 1-x system. Both nanocomposite systems demonstrate plasmonic resonance, hyperbolic dispersion, low losses, and epsilon-near-zero permittivity, making them promising candidates towards direct photonic integration.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Evolving Outer Heliosphere: Tracking Solar Wind Transients from 1 au to the VLISM with IBEX and Voyager 1

Abstract Interstellar Boundary Explorer (IBEX) observations of energetic neutral atom (ENA) fluxes from the heliosphere have greatly enriched our understanding of the interaction of the solar wind (SW) with the local interstellar medium (LISM). However, there has been recent controversy surrounding the inability of most ENA models to produce as high an intensity of ∼0.5–6 keV ENAs as IBEX observes at 1 au, especially as a function of time. In our previous study (E. J. Zirnstein et al.), we introduced a new model that utilizes a data-driven magnetohydrodynamic simulation of the SW–LISM interaction to propagate pickup ions through the heliosheath (HS) after they are nonadiabatically heated at the heliospheric termination shock. E. J. Zirnstein et al. only simulated and analyzed IBEX observations from the direction of Voyager 2. In this study, we expand our model to include fluxes from the direction of Voyager 1, as well as in the low-latitude part (middle) of the ribbon (10° below the ecliptic plane). We show that the model results at Voyager 1 are consistent with E. J. Zirnstein et al.’s results at Voyager 2 in terms of a secondary ENA source contribution of ≲20% from both directions. Our results in the middle of the ribbon also reproduce the data, when including a time-dependent secondary ENA source. Finally, we demonstrate with our simulation that three large pressure waves likely merged in the VLISM and were observed by Voyager 1 as “pf2,” while at least one of the wave’s effects in the HS was observed by IBEX as a brief enhancement in ENA flux in early 2016.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1974

Quinoxaline polymers and copolymers derived from 1, 4-BIS(1'-napthalenyloxayl) benzene

A route for the synthesis of a new monomer, 1,4-bis(1'-naphthalenyl)-oxayl benzene, was devised, and six polymers and copolymers were prepared from this monomer, 1,4-bis(phenyloaxaly)benzene, 3,3'-diaminobenzidine and 3,3',4,4'-tetraaminobenzophenone. Thermogravimetric analysis showed that decomposition of these quinoxaline polymers and copolymers sets in at about 500 C but does not become significant in an inert atmosphere below 600 C. Oxidation becomes significant at about 550 C and the phenylquinoxaline homopolymer is somewhat more oxidation resistant than is the 1-naphthalenylquinoxaline homopolymer. Stress-relaxation measurements showed that, with two exceptions, the homopolymers and copolymers exhibited two second-order transition temperatures, one at about 204.4 C (400 F) and the other at about 315.6 C (600 F). No gross differences in the high temperature plasticity was observed between the naphthalenyl- and the phenyl-quinoaxaline homopolymers. Work was begun on a method for cross-linking polyquinoxalines. A new monomer, p-(methyloxaly)benzil, was synthesized, and model reaction studies showed that cross-linking of 2-methylquinoxaline polymers by a Michael condensation with dimaleimides will probably occur.

Port, W. S.↗
NASA NTRS1976

Quinoxaline polymers and copolymers derived from 1,4-bis(1'-naphthalenyloxalyl)benzene and their graphite composites

Experimental studies were performed with new polyquinoxalines and their graphite composites. Four polymers were synthesized, and then were characterized with respect to their inherent viscosity, elemental chemical analysis, mechanical, and thermodynamic properties. Structural formulas of the polymers and their precursors are given; methods of synthesis are described; and specifically examined was the preparation of polymers from 3,3' diamino-benzidine from 1,4- and 1,3- bis ((1'-napthalenyl) oxalyl) benzene respectively. Also considered was the preparation of polyquinoxalines from poly (p-benzil), and 1,2- aryldiamines.

Port, W. S.↗
NASA NTRS1982

The /A 1 Sigma +/ - /X 1 Sigma +/ system of the isotopic lithium hydrides - The molecular constants, potential energy curves, and their adiabatic corrections

The molecular constants and their adiabatic corrections have been determined for the (A 1 Sigma +) - (X 1 Sigma +) system of the isotopic lithium hydrides: (Li-6)H, (Li-7)H, (Li-6)D, and (Li-7)D. Using a fully quantum mechanical variational method, the potential energy curves (IPA potentials) are determined. Extending the variational method, we have obtained for the first time adiabatic corrections of potential energy curves from isotopic spectroscopic data. A significant difference between the potential energy curves of the lithium hydrides and the lithium deuterides has been observed. When Li-6 was replaced by Li-7, a significant difference was only observed for the (A 1 Sigma +) state, but not for the (X 1 Sigma +) state.

Vidal, C. R.↗
NASA NTRS1984

A second harmonic geomagnetic field line resonance at the inner edge of the plasma sheet - GEOS 1, ISEE 1, and ISEE 2 observations

A description is provided of observations made by GEOS 1, ISEE 1, and ISEE 2 of a hydromagnetic wave with a period approximately 90 s observed near 0200 LT between L = 9 and L = 6, close to the measured inner boundary of the plasma sheet. The wave magnetic oscillations perpendicular to and along the ambient field had similar amplitudes. Using primarily the transverse magnetic components, it is shown that the wave is a second harmonic resonance of the local geomagnetic field lines. ISEE 1 and 2 observed the opposite sense of polarization for about 30 min, although the spacecraft were separated by only 9 min in their orbit; this remarkable feature cannot be explained by either a stationary spatial boundary or a simple temporal boundary but could result from a rapid movement of the resonant region. It is argued that the most likely energy source is bounce resonance with medium energy (approximately 5 keV) ions. Calculations of the wave Poynting vector at ISEE 1 support this conclusion.

Hughes, W. J.↗
NASA NTRS1984

DE 1 observations of type 1 counterstreaming electrons and field-aligned currents

Dynamics Explorer 1 satellite observations of plasma and magnetic fields during type one counterstreaming electron events are presented. Counterstreaming electrons are observed at high altitudes in the region of field-aligned current. The total current density computed from the plasma data in the 18-10,000 eV energy range is generally about 1-2 micro-A/sq m. For the downward current, low-energy electrons contribute more than 40 percent of the total plasma current density integrated above 18 eV. For the upward current, such electrons contribute less than 50 percent of that current density. Electron beams in the field-aligned direction are occasionally detected. The pitch angle distributions of counterstreaming electrons are generally enhanced at both small and large pitch angles. STARE simultaneous observations for one DE 1 pass indicated that the field-aligned current was closed through Pedersen currents in the ionosphere. The directions of the ionospheric current systems are consistent with the DE 1 observations at high altitudes.

Lin, C. S.↗
NASA NTRS1986

Measurements of electron attachment lineshapes and cross sections at ultralow electron energies for c-C6F10, c-C6F12, C8F16 and 1,1,2-C2Cl3F3

Electron attachment cross sections are reported in the electron energy range 0-160 meV and at energy resolutions of 4.5-7.5 meV (FWHM) for the molecules c-C6F10 (perfluorocyclohexene), c-C6F12 (perfluoro-1,2-dimethylcyclobutane), C8F16 (perfluoro-1,3-dimethylcyclohexane) and 1,1,2-C2Cl3F3 (1,1,2-trichlorotrifluoroethane). Use is made of the Kr photoionization technique, and measured attachment lineshapes are converted to cross sections by normalization through attachment rate constants. Comparisons are made with attachment cross sections derived from swarm-measured rate constants. Similar to previous results in eight other molecules, the present four molecules exhibit resolution-limited onsets at a threshold consistent with an s-wave attachment behavior and with a neutral-negative-ion curve crossing at zero energy.

Alajajian, S. H.↗