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At least 1,603 records · Page 89
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Ac2S3 by Materials Project

Ac2S3 is Corundum structured and crystallizes in the trigonal R-3c space group. The structure is three-dimensional. Ac3+ is bonded to six equivalent S2- atoms to form a mixture of distorted corner, edge, and face-sharing AcS6 octahedra. The corner-sharing octahedra tilt angles range from 48–66°. There are three shorter (2.97 Å) and three longer (3.04 Å) Ac–S bond lengths. S2- is bonded to four equivalent Ac3+ atoms to form a mixture of distorted corner and edge-sharing SAc4 trigonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AcGaO3 by Materials Project

AcGaO3 is (Cubic) Perovskite structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Ac3+ is bonded to twelve equivalent O2- atoms to form AcO12 cuboctahedra that share corners with twelve equivalent AcO12 cuboctahedra, faces with six equivalent AcO12 cuboctahedra, and faces with eight equivalent GaO6 octahedra. All Ac–O bond lengths are 2.81 Å. Ga3+ is bonded to six equivalent O2- atoms to form GaO6 octahedra that share corners with six equivalent GaO6 octahedra and faces with eight equivalent AcO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Ga–O bond lengths are 1.99 Å. O2- is bonded in a distorted linear geometry to four equivalent Ac3+ and two equivalent Ga3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AcBO3 by Materials Project

AcBO3 is (Cubic) Perovskite structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Ac3+ is bonded to twelve equivalent O2- atoms to form AcO12 cuboctahedra that share corners with twelve equivalent AcO12 cuboctahedra, faces with six equivalent AcO12 cuboctahedra, and faces with eight equivalent BO6 octahedra. All Ac–O bond lengths are 2.63 Å. B3+ is bonded to six equivalent O2- atoms to form BO6 octahedra that share corners with six equivalent BO6 octahedra and faces with eight equivalent AcO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All B–O bond lengths are 1.86 Å. O2- is bonded in a distorted linear geometry to four equivalent Ac3+ and two equivalent B3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AcNiO3 by Materials Project

AcNiO3 is (Cubic) Perovskite structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Ac3+ is bonded to twelve equivalent O2- atoms to form AcO12 cuboctahedra that share corners with twelve equivalent AcO12 cuboctahedra, faces with six equivalent AcO12 cuboctahedra, and faces with eight equivalent NiO6 octahedra. All Ac–O bond lengths are 2.78 Å. Ni3+ is bonded to six equivalent O2- atoms to form NiO6 octahedra that share corners with six equivalent NiO6 octahedra and faces with eight equivalent AcO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Ni–O bond lengths are 1.97 Å. O2- is bonded in a distorted linear geometry to four equivalent Ac3+ and two equivalent Ni3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AcSe3 by Materials Project

AcSe3 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ac3+ is bonded to twelve Se1- atoms to form AcSe12 cuboctahedra that share corners with four equivalent AcSe12 cuboctahedra, edges with eight equivalent AcSe12 cuboctahedra, edges with sixteen equivalent SeAc4Se8 cuboctahedra, faces with four equivalent AcSe12 cuboctahedra, and faces with eight equivalent SeAc4Se8 cuboctahedra. There are four shorter (3.08 Å) and eight longer (3.48 Å) Ac–Se bond lengths. There are two inequivalent Se1- sites. In the first Se1- site, Se1- is bonded to four equivalent Ac3+ and eight Se1- atoms to form distorted SeAc4Se8 cuboctahedra that share corners with twelve equivalent SeAc4Se8 cuboctahedra, edges with eight equivalent AcSe12 cuboctahedra, edges with eight equivalent SeAc4Se8 cuboctahedra, faces with four equivalent AcSe12 cuboctahedra, and faces with ten equivalent SeAc4Se8 cuboctahedra. There are four shorter (3.08 Å) and four longer (3.48 Å) Se–Se bond lengths. In the second Se1- site, Se1- is bonded in a square co-planar geometry to four equivalent Ac3+ and eight equivalent Se1- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AcHgTe2 by Materials Project

AcHgTe2 is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Ac3+ is bonded in a body-centered cubic geometry to eight equivalent Te2- atoms. All Ac–Te bond lengths are 3.48 Å. Hg1+ is bonded in a body-centered cubic geometry to eight equivalent Te2- atoms. All Hg–Te bond lengths are 3.48 Å. Te2- is bonded in a distorted body-centered cubic geometry to four equivalent Ac3+ and four equivalent Hg1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AcScO3 by Materials Project

AcScO3 is (Cubic) Perovskite structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Ac3+ is bonded to twelve equivalent O2- atoms to form AcO12 cuboctahedra that share corners with twelve equivalent AcO12 cuboctahedra, faces with six equivalent AcO12 cuboctahedra, and faces with eight equivalent ScO6 octahedra. All Ac–O bond lengths are 2.92 Å. Sc3+ is bonded to six equivalent O2- atoms to form ScO6 octahedra that share corners with six equivalent ScO6 octahedra and faces with eight equivalent AcO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Sc–O bond lengths are 2.06 Å. O2- is bonded in a distorted linear geometry to four equivalent Ac3+ and two equivalent Sc3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AcAlO3 by Materials Project

AcAlO3 is (Cubic) Perovskite structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Ac3+ is bonded to twelve equivalent O2- atoms to form AcO12 cuboctahedra that share corners with twelve equivalent AcO12 cuboctahedra, faces with six equivalent AcO12 cuboctahedra, and faces with eight equivalent AlO6 octahedra. All Ac–O bond lengths are 2.75 Å. Al3+ is bonded to six equivalent O2- atoms to form AlO6 octahedra that share corners with six equivalent AlO6 octahedra and faces with eight equivalent AcO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Al–O bond lengths are 1.94 Å. O2- is bonded in a distorted linear geometry to four equivalent Ac3+ and two equivalent Al3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Fuel Cell Buses in U.S. Transit Fleets: Current Status 2020

This report summarizes the progress of fuel cell electric bus (FCEB) development in the United States and discusses the achievements and challenges of introducing fuel cell propulsion in transit. The report provides a summary of results from evaluations performed by the U.S. Department of Energy's (DOE's) National Renewable Energy Laboratory (NREL). The 2020 summary results primarily focus on the most recent data on these FCEBs, from January 2020 through July 2020. The primary results presented in the report are from 25 FCEBs deployed at three agencies: Alameda-Contra Costa Transit District (AC Transit) in Oakland, California (10 FCEBs); Orange County Transportation Authority (OCTA) in Santa Ana, California (10 FCEBs); SunLine Transit Agency in Thousand Palms, California (5 FCEBs).

08 HYDROGEN↗
DOE OSTI2023

Performance Characterization and Energy Savings Assessment of a Radial Flux Surface Permanent Magnet Motor Technology

This project is part of the National Renewable Energy Laboratory's (NREL's) "Commercialization Assistance Program" to provide technical expertise to help emerging companies overcome technical barriers to commercialization. In this study, NREL has evaluated the efficiency and energy saving potential of a novel motor technology designed by ZEUS Motor Inc. located in Wheat Ridge, Colorado. The motor expands on permanent magnet AC motor (PMAC) design to create a new "radial flux, surface PMAC", or RF-sPMAC motor that is expected to outperform other novel motor technologies on the market. Here, the motor showed considerable energy benefits over typical induction motors. The motor benefits from a tightly-packed magnetic steel and copper stator that allows the motor size to be reduced to a thin disc with an internal cavity 1/30th the size of a traditional induction motor. The housing is also aluminum which is magnetically benign. This eliminates the need for external cooling (up to 25 HP), in addition to reducing power consumption.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2025

Tightest Mixed-Integer Programming Formulations for Quadratic SCUC Optimization

In this project, we developed new, tighter Mixed-Integer Programming (MIP) formulations for the combined Alternating Current (AC) Security-Constrained Unit Commitment (SCUC) and Security-Constrained Optimal Power Flow (SCOPF). The work addresses a critical challenge in power system operations: efficiently determining which generation units to commit and how to optimally dispatch them while maintaining network reliability constraints for both normal and contingency scenarios. Our efforts: 1. Advance the Understanding of SCUC/SCOPF Modeling: By introducing tighter MIP formulations and leveraging cutting-edge optimization tools (Julia/JuMP, PowerModels.jl), this project has pushed forward the state of the art in efficient power systems scheduling. 2. Enhance Technical and Economic Feasibility: The methods developed provide more accurate and potentially faster solutions to large-scale, realistic scheduling and dispatch problems in electric power systems, which can translate into improved reliability and potentially lower costs for grid operations. 3. Benefit to the Public: Greater efficiency in power system operations leads to cost savings for utilities and end-users. Improved reliability and integration of advanced modeling approaches can facilitate the adoption of clean energy resources and better accommodate uncertainties in renewable generation. Because this technology could impact bulk power markets and reliability, these innovations have far-reaching public benefits in terms of cost savings, reliability, and sustainability.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2024

A brief review of spin glass magnetometry techniques

Spin glasses are inherently dynamical. Taken properly, measurements of these materials can capture their dynamics and provide a wealth of insight into the physics of the spin glass state. In this methods review, two magnetometry methods are directly compared–ac and dc. Because these measurements are taken differently, the resulting data of each method will contain different information about spin glass behavior. This review will specifically focus on how the out-of-equilibrium effects of aging, rejuvenation, and memory manifest in each of these techniques, and how to construct protocols to measure these effects. We then describe the physical significance of each type of measurement and how to interpret their results. Finally, we explicitly detail which applications are most appropriate for which method. This will help the reader select the most helpful technique to carry out their own future experiments.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Investigation of experimental signatures of spin glass transition temperature

We present a series of temperature and field-dependent magnetization studies of large single-crystal spin glass samples, focusing on both field-cooled (FC) and zero-field-cooled (ZFC) magnetization studies, as well as ac susceptibility measurements. Using the above experimental techniques we aim to understand the nature of spin glass transition in presence of a field, a key factor in understanding the properties of these systems. Building on previous studies that have explored magnetic signatures indicative of spin glass transitions, our research employs a systematic approach to refine the identification of this transition temperature. Through static and dynamic measurements, we aim to shed light on the open issues regarding the key markers of spin glass transitions, enhancing our understanding of these complex systems.

36 MATERIALS SCIENCE↗
NASA NTRS2019

A Study of the Individual Contributions of Heat Generated by a XRISM/Resolve ADR Stage Magnet and Its Magnetic Shielding

A typical Adiabatic Demagnetization Refrigerator (ADR) has modest cooling power, on the order of a few microwatts. Thus, understanding heat loads going into and generated within the ADR is vital to its efficiency as well as the efficiency of the total cryogenic system of a spacecraft. One of the many sources of heat that effects the total cryogenic system is the parasitic heat due to AC loss in the ADR magnet and hysteretic loss in its magnetic shielding during a ramp. Although the sum of the heat from both of these sources can be measured during the operation of the ADR, the individual contributions are not easily obtainable in situ. Therefore, a study is being conducted to experimentally measure the contributions of the parasitic heat produced during ramping from the magnet only and from the magnet-shield combo. This study will give better inputs to the heat load model of the total cryogenic system being built for the X-Ray Imaging and Spectroscopy Mission (XRISM) slated to launch in 2022.

AC Loss↗
NASA NTRSDate not supplied

Laboratory Astrophysics in the United States

Laboratory astrophysics is a strong and vibrant field in the US with its primary national representation as a full Division of the American Astronomical Society (AAS). Laboratory Astrophysics is also represented in other major scientific societies such as the Astrochemistry subdivision of the American Chemical Society (ACS), the High Energy Density Laboratory Astrophysics (HEDLA) and the Division of Astrophysics (DAP) of the American Physical Society (APS) to cite a few. Laboratory Astrophysics and Astrochemistry is also well represented in federal agencies such as the National Aeronautics and Space Administration (NASA) and the National Science Foundation (NSF) where research programs are fully dedicated to the support of laboratory astrophysics research. Laboratory Astrophysics is also well represented in the Academic arena where Physics, Astronomy and/or Chemistry Departments in many universities host a laboratory Astrophysics or Astrochemistry curriculum. The increasing recognition of the field of laboratory astrophysics has been recently reinforced by its inclusion into the recommendations of the two most recent Decadal Surveys of the National Academy of Sciences (NAS). I will discuss and present the many aspects and representations of Laboratory Astrophysics in the US and summarize the current efforts in the field.

Laboratory Astrophysics↗
DOE OSTI2020

Dual 3D Ceramic Textile Electrodes: Fast Kinetics for Carbon Oxidation Reaction and Oxygen Reduction Reaction in Direct Carbon Fuel Cells at Reduced Temperatures

Abstract Direct carbon fuel cells (DCFCs) are an efficient energy‐conversion technology capable of generating electricity with carbon‐dioxide‐capture chemistry with solid carbon as fuels. The efficiency and performance of DCFCs depend on the kinetics of the carbon oxidation reactions (COR) and the oxygen reduction reactions (ORR), each occurring at anode and cathode, respectively. The limited active sites paired with reduced temperatures greatly decrease the efficiency of the electrochemical reactions. Ultraporous dual‐3D ceramic textiles (dual‐3DCT) are integrated into electrolyte‐supported DCFCs to enhance charge and mass transfer at the electrodes. Improved COR at the anode is achieved by the synergy between the 3DCT NiO–Ce 0.8 Gd 0.2 O 1.95 (GDC) structure and optimal carbon fuel choice. In a comparative study, DCFCs using graphitic carbon (GC) as fuel show the best COR performance when compared to DCFCs utilizing alternative fuels such as carbon black (CB) and activated carbon (AC). The 3DCT Sm 0.5 Sr 0.5 CoO 3‐δ –GDC (SSC–GDC) composite cathode shows electrochemical performance superior to that of the conventional screen‐printed SSC–GDC. A peak power density of 392 mW cm −2 at 600 °C is obtained in a DCFC using the 3DCT‐anode/electrolyte/3DCT‐cathode configuration, an unprecedented value for any reported DCFC as of yet. This points toward promising applications of dual‐3DCT electrodes for reduced‐temperature DCFCs.

Bian, Wenjuan↗
DOE OSTI2021

Anisotropic Properties of Quasi‐1D In 4 Se 3 : Mechanical Exfoliation, Electronic Transport, and Polarization‐Dependent Photoresponse

Abstract Theoretical and experimental investigations of various exfoliated samples taken from layered In 4 Se 3 crystals are performed. In spite of the ionic character of interlayer interactions in In 4 Se 3 and hence much higher calculated cleavage energies compared to graphite, it is possible to produce few‐nanometer‐thick flakes of In 4 Se 3 by mechanical exfoliation of its bulk crystals. The In 4 Se 3 flakes exfoliated on Si/SiO 2 have anisotropic electronic properties and exhibit field‐effect electron mobilities of about 50 cm 2 V −1 s −1 at room temperature, which are comparable with other popular transition metal chalcogenide (TMC) electronic materials, such as MoS 2 and TiS 3 . In 4 Se 3 devices exhibit a visible range photoresponse on a timescale of less than 30 ms. The photoresponse depends on the polarization of the excitation light consistent with symmetry‐dependent band structure calculations for the most expected ac cleavage plane. These results demonstrate that mechanical exfoliation of layered ionic In 4 Se 3 crystals is possible, while the fast anisotropic photoresponse makes In 4 Se 3 a competitive electronic material, in the TMC family, for emerging optoelectronic device applications.

Vorobeva, Nataliia S.↗