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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 1,459 records · Page 81
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Comparative study of crystallization kinetics and phase segregation of triple cation and methylammonium lead iodide perovskites on moisture probing using synchrotron X-ray based radiation

3D mixed perovskites have achieved substantial success in boosting solar cell efficiency, but the complicated perovskite crystal formation pathway remains mysterious. Here we present detailed crystallization kinetics of mixed perovskites FA 0.83 MA 0.17 Pb(I 0.83 Br 0.17 ) 3 , where FA is formamidinium and MA is methylammonium, with the addition of Cs + to form a triple cation perovskite (3-CAT), in a comparison with the perovskite building block MAPbI 3 (MAPI) via static grazing-incidence wide-angle X-ray scattering (GIWAXS) and micro-diffraction measurements. Spin-coated films produced α-perovskite peaks with no PbI 2 or δ-intermediate phases, which was a promising result for the 3-CAT perovskite from micro-diffraction measurements. However, the 3-CAT did not remain stable on probing with varied relative humidity (RH) conditions as segregation back to the δ-intermediate and PbI 2 phase after 10 s of exposure to an RH value of 11% was found to occur from the GIWAXS results. When RH levels were elevated to over 100%, segregation peaks of PbI 2 and δ-intermediate (2H, 4H and 6H) became conspicuous as the α-phase intensity diminished, unlike for MAPI that remains relatively stable. The possible cause of this is hydrophilic bonds that form between the 3-CAT crystals and the small annealing window of the best composition perovskite (5% Cs + ) film.

Shatsala, Miller (ORCID:0009000927230192)↗
DOE OSTI2018

PhaseChange Material Freezing in an Energy Storage Module for a Micro Environmental ControlSystem

This study analyzes phase change material (PCM) freezing process in a novel latent heat storage device (LHSD). Heat is removed from the PCM with an embedded evaporator. A mathematical model of freezing in a finite-thickness PCM slab is presented. An experimentally validated reduced-order model (ROM) based on the mathematical model was developed to analyze the heat transfer between the freezing PCM and an evaporating refrigerant flowing inside a flat, microchannel tube coil embedded in the PCM. A detailed finite element model (FEM) of the same device was also developed and employed to verify the validity of the ROM over a wider range of conditions. The freezing times and total “cooling” stored in the PCM computed by the ROM agree very well with those computed by the detailed FEM. The ROM executes in ~1 min for a full heat exchanger, compared with more than 10 h for the FEM, making the former much more practical for use in parametric analysis and optimization of design alternatives.

Engineering↗
DOE OSTI2018

Formation of Compounds in the Ag{sub 2}O–Sb{sub 2}O{sub 3}–MoO{sub 3} System on Heating

This paper presents a detailed study of phase formation processes in the AgNO{sub 3}–Sb{sub 2}O{sub 3}–MoO{sub 3} system during heating in air. The compositions of the solid-state reaction products have been determined using thermogravimetry and qualitative X-ray diffraction. The results demonstrate that, at a final heat treatment temperature of 1023 K, synthesis yields a range of Ag{sub 2–x}Sb{sub 2–x}Mo{sub x}O{sub 6} compounds with the pyrochlore structure and 0.0 ≤ x ≤ 2.0. The structural parameters of the synthesized phases have been refined by the Rietveld method in space group Fd3̅m and their electrical conductivity has been measured.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Anisotropy of the Complex Permittivity of the Kagome-Staircase Compounds Co{sub 3}V{sub 2}O{sub 8} and Ni{sub 3}V{sub 2}O{sub 8}: Experiment and Ab Initio Calculations

The anisotropy of the components of the complex permittivity of vanadate Co{sub 3}V{sub 2}O{sub 8} and Co{sub 3}V{sub 2}O{sub 8} single crystals in the paramagnetic phase are studied by optical ellipsometry in the spectral region 0.5–5.0 eV. Our experimental results support the weak anisotropy of the optical response detected earlier for axes a and c. The optical properties are also investigated along axis b. The properties of both compounds are compared. The optical spectra of both compounds along axis b are shifted toward low energies as compared to axes a and c. The maximum of the main interband absorption band of Co{sub 3}V{sub 2}O{sub 8} is shifted toward low energies by 0.25–0.3 eV as compared to Co{sub 3}V{sub 2}O{sub 8}. The electronic structure parameters of both compounds are determined. Optical function spectra are analyzed using the results of ab initio band calculations.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2017

Single-phase epitaxial InFeSb layers with a Curie temperature above room temperature

Epitaxial InFeSb/GaAs heterostructures were obtained by laser deposition in vacuum. Investigations by high-resolution transmission electron microscopy and microdiffraction showed that the InFeSb layers are single-crystal and do not contain additional phase inclusions. Study of their magnetotransport properties have revealed that an anomalous Hall effect and a negative magnetoresistance up to room temperature are observed in the structures.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2019

Study of Kinetics of Solid Phase Transition in Tetracosane С{sub 24}Н{sub 50} by High-Resolution Synchrotron X-Ray Powder Diffraction

Using the small-angle synchrotron X-ray diffraction method at the research facility “BELOK” of the Kurchatov synchrotron radiation source at the NRC Kurchatov Institute, it was shown that the first-order solid phase transition in tetracosane C{sub 24}H{sub 50} passes according to a heterogeneous mechanism in a narrow temperature range ΔT ~ 1 K in accordance with the theory of diffuse phase transitions.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Cobalt Modification of Thin Rutile Films Magnetron-Sputtered in Vacuum

Using X-ray phase analysis, atomic force microscopy, and secondary ion mass-spectrometry, the phase formation and component distribution in a Co–TiO{sub 2} film system have been investigated during magnetron sputtering of the metal on the oxide and subsequent vacuum annealing. It has been found that cobalt diffuses deep into titanium oxide to form complex oxides CoTi{sub 2}O{sub 5} and CoTiO{sub 3}. A mechanism behind their formation at grain boundaries throughout the thickness of the TiO{sub 2} film is suggested. It assumes the reactive diffusion of cobalt along grain boundaries in the oxide. A quantitative model of reactive interdiffusion in a bilayer polycrystalline metal–oxide film system with limited solubility of components has been developed. The individual diffusion coefficients of cobalt and titanium have been determined in the temperature interval 923–1073 K.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Phase Portrait of a Scattered Charged-Particle Bunch

The distribution function of a moving charge experiencing multiple Coulomb scattering has been used to derive relationships for the scattered beam parameters through the parameters of a beam incident on a target. The notion of a beam consistent with a target has been introduced, and a formula has been derived that relates the emittances of the incident and scattered beams.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2019

Intermittency at the Boundary of Generalized Synchronization in Mutually Coupled Systems with Complex Attractor Topology

The mechanisms of occurrence and characteristics of intermittency at the boundary of generalized synchronization in mutually coupled systems with complex (two-sheet) chaotic attractor topology are investigated. It has been established that the occurrence of intermittency in this case is due to the imaging point jump from one sheet of the chaotic attractor to another. At the same time, distributions of laminar phase durations and dependences of average laminar phase durations on the supercriticality parameter obey exponential laws.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2018

The Gas-Phase Synthesis of a New Functional Hybrid Material on the Basis of Multiwalled Carbon Nanotubes Decorated with Faceted Aluminum Nanocrystals

The deposition of polyhedral aluminum nanocrystals onto the surface of multiwalled carbon nanotubes (MWCNTs) via metalorganic chemical vapor deposition with the use of triisobutylaluminum as the precursor has been performed for the first time. The new hybrid nanomaterial (Al/MWCNTs) has been characterized by X-ray phase analysis, scanning electron microscopy, and high-resolution transmission electron microscopy. The obtained Al/MWCNTs hybrid materials were tested as the filler for the creation of threedimensional composites on the basis of an AMg2 alloy via powder metallurgy. It has been shown that the use of Al/MWCNTs as the filler increases the hardness of the composites by 18% in comparison with the initial MWCNTs.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2021

Spectra and mean multiplicities of $π^-$ in central 40 Ar+ 45 Sc collisions at 13A, 19A, 30A, 40A, 75A and 150A Ge V / c beam momenta measured by the NA61/SHINE spectrometer at the CERN SPS

The physics goal of the strong interaction program of the NA61/SHINE experiment at the CERN Super Proton Synchrotron (SPS) is to study the phase diagram of hadronic matter by a scan of particle production in collisions of nuclei with various sizes at a set of energies covering the SPS energy range. This paper presents differential inclusive spectra of transverse momentum, transverse mass and rapidity of π - mesons produced in central 40 Ar+ 45 Sc collisions at beam momenta of 13A, 19A, 30A, 40A, 75A and 150A Ge V /c. Energy and system size dependence of parameters of these distributions – mean transverse mass, the inverse slope parameter of transverse mass spectra, width of the rapidity distribution and mean multiplicity – are presented and discussed. Furthermore, the dependence of the ratio of the mean number of produced pions to the mean number of wounded nucleons on the collision energy was derived. The results are compared to predictions of several models.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2020

Role of Oxygen on Chemical Segregation in Uncapped Ge 2 Sb 2 Te 5 Thin Films on Silicon Nitride

Germanium antimony telluride has been the most used and studied phase-change material for electronic memory due to its suitable crystallization temperature, amorphous to crystalline resistance contrast, and stability of the amorphous phase. In this paper, the segregation of Ge in a Ge 2 Sb 2 Te 5 film of 30 nm thickness during heating inside the transmission electron microscope was observed and characterized. Furthermore, Ge 2 Sb 2 Te 5 film was deposited using sputtering on a Protochips Fusion holder and left uncapped in atmosphere for about four months. Oxygen incorporated within the film played a significant role in the chemical segregation observed which resulted in amorphous Ge-O island boundaries and Sb and Te rich crystalline domains. Such composition changes can occur when the phase-change material interfaces insulating oxide layers in an integrated device and can significantly impact its electrical and thermal properties.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Two Marine Heatwave (MHW) Variants under a Basinwide MHW Conditioning Mode in the North Pacific and Their Atlantic Associations

Abstract During 2013–16 and 2018–22, marine heatwaves (MHWs) occurred in the North Pacific, exhibiting similar extensive coverage, lengthy duration, and significant intensity but with different warming centers. The warming center of the 2013–16 event was in the Gulf of Alaska (GOA), while the 2018–22 event had warming centers in both the GOA and the coast of Japan (COJ). Our observational analysis indicates that these two events can be considered as two MHW variants induced by a basinwide MHW conditioning mode in the North Pacific. Both variants were driven thermodynamically by atmospheric wave trains propagating from the tropical Pacific to the North Pacific, within the conditioning mode. The origin and propagating path of these wave trains play a crucial role in determining the specific type of MHW variant. When a stronger wave train originates from the tropical central (western) Pacific, it leads to the GOA (COJ) variant. The cross-basin nature of the wave trains enables the two MHW variants to be accompanied by a tripolar pattern of sea surface temperature anomalies in the North Atlantic but with opposite phases. The association of these two MHW variants with the Atlantic Ocean also manifests in the decadal variations of their occurrence. Both variants tend to occur more frequently during the positive phase of the Atlantic multidecadal oscillation but less so during the negative phase. This study underscores the importance of cross-basin associations between the North Pacific and North Atlantic in shaping the dynamics of North Pacific MHWs.

Meteorology & Atmospheric Sciences↗
DOE OSTI2020

Ground-State In-Plane Light-Holes in GaAs/AlGaAs Structures [Book Chapter]

We have performed low-temperature magnetoluminescence, far-infrared cyclotron resonance, and magneto-transport measurements on narrow (4.5 nm) GaAs/Al 0.25 Ga 0.75 As single quantum-wells. The ground state in-plane valence band was found to be light and very nonparabolic, i.e., at zone center, the valence band mass is m v ≈ 0. 1 and for E f ≈ 10 meV, m v ≈ 0.25.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Discharge Permit-1845 Quarterly Status Report April 2018

Discharge Permit (DP)-1845 was issued by the New Mexico Environment (NMED) Ground Water Quality Bureau (GWQB) for discharges via up to three injection wells in a phased Treatability Study of in-situ bioremediation of groundwater at Sandia National Laboratories, New Mexico, Technical Area-V Groundwater Area of Concern. This report fulfills the quarterly reporting requirements set forth in DP-1845, Section IV.B, Monitoring and Reporting. This reporting period is October 1st through December 31st, 2017. The report is due to NMED GWQB by May 1st, 2018.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2019

Discharge Permit DP-1845 Quarterly Report (July — September 2018)

Discharge Permit (DP)-1845 was issued by the New Mexico Environment (NMED) Ground Water Quality Bureau (GWQB) for discharges via up to three injection wells in a phased Treatability Study of in-situ bioremediation of groundwater at the Sandia National Laboratories, New Mexico, Technical Area-V Groundwater Area of Concern. This report fulfills the quarterly reporting requirements set forth in DP-1845, Section IV.B, Monitoring and Reporting. This reporting period is July 1 through September 30, 2018. The report is due to NMED GWQB by February 1, 2019.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2019

Forward Osmosis-based System for Treatment of Waste Water Generated During Energy Production Using Waste Carbon Dioxide and Waste Heat. Final Report

The installation of COHO at a power plant will reduce the volume of wastewater, reduce the energy costs to treat wastewater, expand the capabilities of water treatment all while reducing the cost of carbon capture from flue gas. In Phase IIB studies, Porifera explored the use of a next-generation COHO system to synergistically capture carbon dioxide from flue gas and treat wastewater at power plants. We found that the next generation system benefits from improved operational efficiency and safety. In addition, we performed a technoeconomic analysis of the system and found it to save significant cost compared to conventional technologies.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2019

Discharge Permit-1845 (Quarterly Report)

Discharge Permit (DP)-1845 was issued by the New Mexico Environment (NMED) Ground Water Quality Bureau (GWQB) for discharges via up to three injection wells in a phased Treatability Study of in-situ bioremediation of groundwater at the Sandia National Laboratories, New Mexico, Technical Area-V Groundwater Area of Concern. This report fulfills the quarterly reporting requirements set forth in DP-1845, Section IV.B, Monitoring and Reporting. This reporting period is October 1 through December 31, 2018. The report is due to NMED GWQB by May 1, 2019.

54 ENVIRONMENTAL SCIENCES↗