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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 433 records · Page 24
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Taming Metal–Solid Electrolyte Interface Instability via Metal Strain Hardening

Abstract Solid-state lithium metal batteries have emerged as a promising technology for electric vehicles due to their high specific energy and safety potential. Obtaining intimate contact between Li and electrolyte during cell fabrication, however, remains challenging. Adequate fabrication pressure is required to promote close contact, but this pressure can cause Li deformation and penetration into the electrolyte, resulting in poor battery performance. Here, a strategy for addressing this problem is presented by incorporating 3 at% Mg into Li. Unlike pure Li which obeys the Voce hardening law and allows unconstrained deformation, Li–Mg alloy follows the Swift hardening law and strengthens with strain under compression stress. Because of the constrained deformation of Li–Mg, intimate contact with solid electrolytes is possible even at high fabrication pressure (50–65 MPa), resulting in high critical current densities. These findings underscore the importance of understanding Li metal deformation properties to improve solid-state battery performance.

25 ENERGY STORAGE↗
DOE OSTI2022

Novel Class of Rhenium Borides Based on Hexagonal Boron Networks Interconnected by Short B 2 Dumbbells

Transition metal borides are known due to their attractive mechanical, electronic, refractive, and other properties. A new class of rhenium borides was identified by synchrotron single-crystal X-ray diffraction experiments in laser-heated diamond anvil cells between 26 and 75 GPa. Recoverable to ambient conditions, compounds rhenium triboride (ReB 3 ) and rhenium tetraboride (ReB 4 ) consist of close-packed single layers of rhenium atoms alternating with boron networks built from puckered hexagonal layers, which link short bonded (~ 1.7 angstrom) axially oriented B 2 dumbbells. The short and incompressible Re-B and B-B bonds oriented along the hexagonal c-axis contribute to low axial compressibility comparable with the linear compressibility of diamond. Sub-millimeter samples of ReB 3 and ReB 4 were synthesized in a large-volume press at pressures as low as 33 GPa and used for material characterization. Crystals of both compounds are metallic and hard (Vickers hardness, H V = 34(3) GPa). Geometrical, crystal-chemical, and theoretical analysis considerations suggest that potential ReB x compounds with x > 4 can be based on the same principle of structural organization as in ReB 3 and ReB 4 and possess similar mechanical and electronic properties.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Refractive index of lithium fluoride at high dynamic stresses

Alkali halides are prototypical ionic solids whose refractive index is a fundamental property related to their lattice structure and ionic polarizability. In particular, lithium fluoride (LiF) has the largest band gap of any known transparent material and maintains transparency at high pressures, making it well suited for use as an optical window in dynamic compression experiments. While empirical fits to the measured density dependence of the refractive index have been provided, a model that is valid over the entire pressure range of experiments and based on a polarization-based theoretical description is lacking. We present a refractive index model for dynamically compressed LiF based on the Lorentz-Lorenz equation, where the molecular polarizability is determined using a single oscillator model with a strain polarizability parameter Λ=0.73. Here, we show that our modeling approach provides an excellent match to the LiF refractive index data for both shock and ramp compression experiments to 900 GPa (density compression greater than threefold). Additionally, updated fits are provided to determine the refractive index correction for LiF windows used in dynamic compression experiments.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2020

Descriptors for Hydrogen Evolution on Single Atom Catalysts in Nitrogen-Doped Graphene

Single-atom catalysts (SACs) are a new research frontier in electrocatalysis such as in the hydrogen evolution reaction (HER). Recent theoretical and experimental studies have demonstrated that certain M–N–C (metal–nitrogen–carbon) based SACs exhibit excellent performance for HER. Here we report a new approach to tune HER activity for SACs by changing the size and dimensionality of the carbon substrate while maintaining the same coordination environment. In this work, we screen the 3d, 4d, and 5d transition metal SACs in N-doped 2D graphene and nanographenes of several sizes for HER using first-principles density functional theory (DFT). Nanographenes containing V, Rh, and Ir are predicted to have significantly enhanced HER activity compared to their 2D graphene counterparts. We turn to machine learning to accurately predict the free energy of hydrogen adsorption (ΔGH) based on various descriptors and compressed sensing to identify key descriptors for activity, which can be used to further screen for additional candidates.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1997

Gravitational evidence for an undifferentiated Callisto

Before the arrival of the Galileo spacecraft at Jupiter, models for the interior structure of the four galilean satellites--Io, Europa, Ganymede and Callisto-ranged from uniform mixtures of rock and ice (that is, undifferentiated objects) or rocky cores surrounded by a mantle of water ice. Now it appears that Io has a large metallic core and that Ganymede is strongly differentiated, most probably into a three-layer structure consisting of a metallic core, a silicate mantle and a deep outer layer of ice. Direct information on the interior structure of Callisto determined from previous spacecraft fly-bys was essentially limited to an estimate of the mean density being intermediate between pure ice and pure rock. Here we report measurements of Callisto's gravitational field which reveal that, in contrast to Io and Ganymede, this galilean satellite is most probably a homogeneous object consisting of a solar mixture of 40% compressed ice and 60% rock (including iron and iron sulphide). Callisto's undifferentiated state is consistent with the apparent lack of an intrinsic magnetic field, and indicates that the outermost galilean satellite has not experienced a heating phase sufficiently high to separate its rock and metal components from the lighter ices.

unmanned↗
DOE OSTI2019

Experimental observations of large changes in electron density distributions in β - Ge

We report the electron density distributions in β-Ge have been experimentally determined at in situ high-pressure conditions using synchrotron diffraction techniques in a diamond anvil cell. Upon decompression, the electron density along the $c$ axis in tetragonal β-Ge displays a sudden drop at 10–11 GPa close to that of the structural α-β transition, while the β-Ge samples remain as single crystals until transforming to metastable Ge phases around 6.7–8.5 GPa. In contrast to the covalently bonded α-Ge that displays only a weak participation of $d$ electrons in the valence band under compression above 7.7 GPa, our experimental results suggest that a large change in $d$-orbital participation can occur in the β-Ge lattice which has mixed covalent and metallic bonding. The β-Ge below 10 GPa may display large fluctuations in electronic properties, which sheds light for exploring novel materials with intriguing electronic and optical properties.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Structural and vibrational behavior of 2 H -NbSe 2 at high pressures

In this work, the high-pressure structural and vibrational properties of a layered transition metal dichalcogenide 2 H -NbSe 2 were investigated using single-crystal x-ray diffraction and Raman spectroscopy, demonstrating its structural stability up to 35 GPa. The lattice compressibility changes character from being highly anisotropic at low pressures to largely isotropic at high pressures. Concomitantly, the interatomic bonds demonstrate highly anisotropic compression behavior with the Se-Se interlayer bonds compressing by >20%, while the intramolecular Se-Se distance shows a nonmonotonic pressure dependence with a maximum at-12 GPa. The nearest-neighbor central force lattice vibrational model yields pressure dependencies of the interatomic forces in qualitative agreement with bond length compression, providing insight into the vibrational properties of 2 H -NbSe 2 at high pressures.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
NASA NTRS1972

Mechanically prestressed windows

A method was developed for mechanically prestressing glass used in spacecraft windows so that surface imperfections of the glass will not propagate under stress. A metal ring, in tension, is placed around the periphery of the glass where the interference fit between the ring and glass fixes the glass in a state of uniform compression. When the glass is subjected to a pressure loading, the compressive prestress prevents tension loading of the outer surface and, therefore, eliminates the tendency for propagation of surface imperfections.

Keathley, W. H.↗
DOE OSTI2021

Concentric Ring Gas Atomization Die Design for Optimized Particle Production

In partnership with Linde plc (formerly Praxair, Inc.), Ames Laboratory will further develop and commercialize its concentric-ring high pressure gas atomization (CR-HPGA) gas-die technology with a goal to improve the precision of metal powder production in a desired size range and quality. The successful commercialization of this technology could reduce production cost of metal powders and improve reliability of this industrial process, increasing specialty alloy powder availability for new applications and adoption into additive manufacturing and multiple materials sectors. The project scope is to [1] utilize AMES compressible gas flow and melt break-up models to explore a wide swath of parameter space available for the CR-HPGA technology, identifying the most promising gas-die designs for fabrication, [2] verify and optimize the new gas-die design, fabricate it and select preferred operating parameters by gas-only flow imaging and aspiration pressure measurements, down-selecting gas compositions and atomization parameters for full scale testing, [3] perform pilot-scale atomization trials with Al and/or Cu alloys of a new CR-HPGA gas-die at selected parameters, [4] evaluate gas-die performance by comparing resulting powder size distribution and powder quality attributes with equivalent powders made by conventional close-coupled HPGA technology, and [5] assess (through Praxair partnership) reduction in operational costs of new CR-HPGA gas-die through the use of an inert gas recovery/recycling system. In partnership with Praxair, Inc., the team, led by Ames Laboratory senior metallurgist Iver Anderson, intend to demonstrate the performance of an optimized CR-HPGA gas-die design in a pilot scale atomizer and better understand the design and operational controls to increase overall benefits for precision metal powder production.

42 ENGINEERING↗
DOE OSTI2023

The effect of annealing on kink band formation in Ag/Fe nanolaminates

Kink banding is a common, though not well understood, failure mechanism in anisotropic materials such as nano metallic laminates (NMLs). In this work, we investigate the effect of annealing on kink band (KB) formation in Ag/Fe NMLs prepared by accumulative roll bonding (ARB) using in situ micropillar compression, scanning/transmission electron microscopy (S/TEM), and transmission Kikuchi diffraction (TKD) analyses. Our results show that annealing increases the KB initiation strain, decreases the probability of KB formation, and decreases the load drop magnitude accompanying kink banding in Ag/Fe NMLs. Post-compression analyses reveal that annealing facilitates more uniform deformation of pillars and affects the formation of geometrically necessary grain boundaries (GNBs) near the kink band boundary (KBB). Compared to its as-rolled counterpart, annealed Ag/Fe has wider KBs with blunter KBBs.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Development of uncertainty-aware equation-of-state models: Application to copper

Sophisticated hydrodynamic codes are commonly used to understand and predict events relevant to natural and applied sciences. The degree to which these simulations reflect reality, however, is dependent on how well we understand the materials and underlying physics involved. These research communities need material models that communicate the uncertainty in the physical properties, which at their basest form comes from the uncertainty in the underlying experimental measurements. Additionally, we have constructed a new framework for using both experimental measurements and the associated experimental uncertainties to build equation-of-state models that reflect not only current best measurements but also the accuracy of those measurements. This method had been used to construct an ensemble of equation-of-state models for copper that communicates the experimental uncertainties in the data through the equation-of-state model, which is available for application in any simulation metric of interest.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2021

RapidClave® Technology Demonstrations – II Hat Stiffener

This project sought to evaluate the cost and performance of both polymeric and metallic tooling for use with the RapidClave® composite process. Teijin’s rapid cure carbon/epoxy prepreg, Q183, was selected to fabricate demonstration components, of aerospace design, which currently are fabricated via compression molding using matched steel tooling. The ability to fabricate components using this prepreg in the RapidClave®, and using low cost single sided tooling, could significantly reduce the cost of part manufacture and shorten production lead times for tooling fabrication. The component demonstration article was a “hat stiffener” geometry typically used to reinforce fuselage or wing skins of an aircraft. A rapid preforming process was demonstrated and rapid process cycle times similar to compression molding were achieved by placing the preform on hot tooling, thus avoiding the time and energy associated with typical thermal cycling. A 90% reduction in tooling cost was achieved through the use of single sided aluminum or polymeric additive tooling when compared to compression molding matched steel tooling. In addition to rapid cycle times, RapidClave® offers the ability to change out tooling in minutes such that multiple part geometries can be fabricated in one shift.

36 MATERIALS SCIENCE↗
NASA NTRS2007

Cosmological Effects of Powerful AGN Outbursts in Galaxy Clusters: Insights from an XMM-Newton Observation of MS 0735+7421

We report on the results of an analysis o f XMM-Newton observations o f MS 0735+7421, the galaxy cluster that hosts the most energetic AGN outburst currently known. .The previous chandra image shows twin giant x-ray cavities (approx.200 kpc diameter) filled with radio emission and surrounded by a weak shock front. XMM data are consistent with these findings. The total energy in cavities and shock (1E62 erg(approx.100 kpc), to heat the gas within 1 Mpc by approx.1/4 kev per particle. The cluster exhibits an upward departure (factor approx.2) from the mean L-T relation. The boost in emissivity produced by the ICM compression in the bright shells due to the cavity expansion may contribute to explain the high luminosity and high central gas mass fraction that we measure. The scaled temperature and metallicity profiles are in general agreement with those observed in re1axed clusters. Also, the quantities we measure are consistent with the observed M-T relation. We conclude that violent outbursts such as the one in MS 0735+7421 do not cause dramatic scaling relations (other than the L-T relation). However, if they are relatively common they may play a role in creating the global cluster properties.

Gitti, M.↗
NASA NTRS2010

NASA Tech Briefs, March 2010

Topics covered include: Software Tool Integrating Data Flow Diagrams and Petri Nets; Adaptive Nulling for Interferometric Detection of Planets; Reducing the Volume of NASA Earth-Science Data; Reception of Multiple Telemetry Signals via One Dish Antenna; Space-Qualified Traveling-Wave Tube; Smart Power Supply for Battery-Powered Systems; Parallel Processing of Broad-Band PPM Signals; Inexpensive Implementation of Many Strain Gauges; Constant-Differential-Pressure Two-Fluid Accumulator; Inflatable Tubular Structures Rigidized with Foams; Power Generator with Thermo-Differential Modules; Mechanical Extraction of Power From Ocean Currents and Tides; Nitrous Oxide/Paraffin Hybrid Rocket Engines; Optimized Li-Ion Electrolytes Containing Fluorinated Ester Co-Solvents; Probabilistic Multi-Factor Interaction Model for Complex Material Behavior; Foldable Instrumented Bits for Ultrasonic/Sonic Penetrators; Compact Rare Earth Emitter Hollow Cathode; High-Precision Shape Control of In-Space Deployable Large Membrane/Thin-Shell Reflectors; Rapid Active Sampling Package; Miniature Lightweight Ion Pump; Cryogenic Transport of High-Pressure-System Recharge Gas; Water-Vapor Raman Lidar System Reaches Higher Altitude; Compact Ku-Band T/R Module for High-Resolution Radar Imaging of Cold Land Processes; Wide-Field-of-View, High-Resolution, Stereoscopic Imager; Electrical Capacitance Volume Tomography with High-Contrast Dielectrics; Wavefront Control and Image Restoration with Less Computing; Polarization Imaging Apparatus; Stereoscopic Machine-Vision System Using Projected Circles; Metal Vapor Arcing Risk Assessment Tool; Performance Bounds on Two Concatenated, Interleaved Codes; Parameterizing Coefficients of a POD-Based Dynamical System; Confidence-Based Feature Acquisition; Algorithm for Lossless Compression of Calibrated Hyperspectral Imagery; Universal Decoder for PPM of any Order; Algorithm for Stabilizing a POD-Based Dynamical System; Mission Reliability Estimation for Repairable Robot Teams; Processing AIRS Scientific Data Through Level 3; Web-Based Requesting and Scheduling Use of Facilities; AutoGen Version 5.0; Time-Tag Generation Script; PPM Receiver Implemented in Software; Tropospheric Emission Spectrometer Product File Readers; Reporting Differences Between Spacecraft Sequence Files; Coordinating "Execute" Data for ISS and Space Shuttle; Database for Safety-Oriented Tracking of Chemicals; Apparatus for Cold, Pressurized Biogeochemical Experiments; Growing B Lymphocytes in a Three-Dimensional Culture System; Tissue-like 3D Assemblies of Human Broncho-Epithelial Cells; Isolation of Resistance-Bearing Microorganisms; Oscillating Cell Culture Bioreactor; and Liquid Cooling/Warming Garment.

Source record↗
NASA NTRS2013

Modeling Commercial Turbofan Engine Icing Risk With Ice Crystal Ingestion

The occurrence of ice accretion within commercial high bypass aircraft turbine engines has been reported under certain atmospheric conditions. Engine anomalies have taken place at high altitudes that have been attributed to ice crystal ingestion, partially melting, and ice accretion on the compression system components. The result was degraded engine performance, and one or more of the following: loss of thrust control (roll back), compressor surge or stall, and flameout of the combustor. As ice crystals are ingested into the fan and low pressure compression system, the increase in air temperature causes a portion of the ice crystals to melt. It is hypothesized that this allows the ice-water mixture to cover the metal surfaces of the compressor stationary components which leads to ice accretion through evaporative cooling. Ice accretion causes a blockage which subsequently results in the deterioration in performance of the compressor and engine. The focus of this research is to apply an engine icing computational tool to simulate the flow through a turbofan engine and assess the risk of ice accretion. The tool is comprised of an engine system thermodynamic cycle code, a compressor flow analysis code, and an ice particle melt code that has the capability of determining the rate of sublimation, melting, and evaporation through the compressor flow path, without modeling the actual ice accretion. A commercial turbofan engine which has previously experienced icing events during operation in a high altitude ice crystal environment has been tested in the Propulsion Systems Laboratory (PSL) altitude test facility at NASA Glenn Research Center. The PSL has the capability to produce a continuous ice cloud which are ingested by the engine during operation over a range of altitude conditions. The PSL test results confirmed that there was ice accretion in the engine due to ice crystal ingestion, at the same simulated altitude operating conditions as experienced previously in flight. The computational tool was utilized to help guide a portion of the PSL testing, and was used to predict ice accretion could also occur at significantly lower altitudes. The predictions were qualitatively verified by subsequent testing of the engine in the PSL. The PSL test has helped to calibrate the engine icing computational tool to assess the risk of ice accretion. The results from the computer simulation identified prevalent trends in wet bulb temperature, ice particle melt ratio, and engine inlet temperature as a function of altitude for predicting engine icing risk due to ice crystal ingestion.

Jorgenson, Philip C. E.↗
NASA NTRS2014

Modeling of Commercial Turbofan Engine With Ice Crystal Ingestion: Follow-On

The occurrence of ice accretion within commercial high bypass aircraft turbine engines has been reported under certain atmospheric conditions. Engine anomalies have taken place at high altitudes that have been attributed to ice crystal ingestion, partially melting, and ice accretion on the compression system components. The result was degraded engine performance, and one or more of the following: loss of thrust control (roll back), compressor surge or stall, and flameout of the combustor. As ice crystals are ingested into the fan and low pressure compression system, the increase in air temperature causes a portion of the ice crystals to melt. It is hypothesized that this allows the ice-water mixture to cover the metal surfaces of the compressor stationary components which leads to ice accretion through evaporative cooling. Ice accretion causes a blockage which subsequently results in the deterioration in performance of the compressor and engine. The focus of this research is to apply an engine icing computational tool to simulate the flow through a turbofan engine and assess the risk of ice accretion. The tool is comprised of an engine system thermodynamic cycle code, a compressor flow analysis code, and an ice particle melt code that has the capability of determining the rate of sublimation, melting, and evaporation through the compressor flow path, without modeling the actual ice accretion. A commercial turbofan engine which has previously experienced icing events during operation in a high altitude ice crystal environment has been tested in the Propulsion Systems Laboratory (PSL) altitude test facility at NASA Glenn Research Center. The PSL has the capability to produce a continuous ice cloud which is ingested by the engine during operation over a range of altitude conditions. The PSL test results confirmed that there was ice accretion in the engine due to ice crystal ingestion, at the same simulated altitude operating conditions as experienced previously in flight. The computational tool was utilized to help guide a portion of the PSL testing, and was used to predict ice accretion could also occur at significantly lower altitudes. The predictions were qualitatively verified by subsequent testing of the engine in the PSL. In a previous study, analysis of select PSL test data points helped to calibrate the engine icing computational tool to assess the risk of ice accretion. This current study is a continuation of that data analysis effort. The study focused on tracking the variations in wet bulb temperature and ice particle melt ratio through the engine core flow path. The results from this study have identified trends, while also identifying gaps in understanding as to how the local wet bulb temperature and melt ratio affects the risk of ice accretion and subsequent engine behavior.

Jorgenson, Philip C. E.↗
NASA NTRS2014

Modeling of Commercial Turbofan Engine with Ice Crystal Ingestion; Follow-On

The occurrence of ice accretion within commercial high bypass aircraft turbine engines has been reported under certain atmospheric conditions. Engine anomalies have taken place at high altitudes that have been attributed to ice crystal ingestion, partially melting, and ice accretion on the compression system components. The result was degraded engine performance, and one or more of the following: loss of thrust control (roll back), compressor surge or stall, and flameout of the combustor. As ice crystals are ingested into the fan and low pressure compression system, the increase in air temperature causes a portion of the ice crystals to melt. It is hypothesized that this allows the ice-water mixture to cover the metal surfaces of the compressor stationary components which leads to ice accretion through evaporative cooling. Ice accretion causes a blockage which subsequently results in the deterioration in performance of the compressor and engine. The focus of this research is to apply an engine icing computational tool to simulate the flow through a turbofan engine and assess the risk of ice accretion. The tool is comprised of an engine system thermodynamic cycle code, a compressor flow analysis code, and an ice particle melt code that has the capability of determining the rate of sublimation, melting, and evaporation through the compressor flow path, without modeling the actual ice accretion. A commercial turbofan engine which has previously experienced icing events during operation in a high altitude ice crystal environment has been tested in the Propulsion Systems Laboratory (PSL) altitude test facility at NASA Glenn Research Center. The PSL has the capability to produce a continuous ice cloud which is ingested by the engine during operation over a range of altitude conditions. The PSL test results confirmed that there was ice accretion in the engine due to ice crystal ingestion, at the same simulated altitude operating conditions as experienced previously in flight. The computational tool was utilized to help guide a portion of the PSL testing, and was used to predict ice accretion could also occur at significantly lower altitudes. The predictions were qualitatively verified by subsequent testing of the engine in the PSL. In a previous study, analysis of select PSL test data points helped to calibrate the engine icing computational tool to assess the risk of ice accretion. This current study is a continuation of that data analysis effort. The study focused on tracking the variations in wet bulb temperature and ice particle melt ratio through the engine core flow path. The results from this study have identified trends, while also identifying gaps in understanding as to how the local wet bulb temperature and melt ratio affects the risk of ice accretion and subsequent engine behavior.

Jorgenson, Philip C. E.↗