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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 847 records · Page 47
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Analyzing the Subjectivity of Hole-Type Image Quality Indicators for Radiography

Hole-type penetrameters used as image quality indicators (IQIs) for radiography have an inherent degree of subjectivity to their interpretation. The 1T (one times the thickness of the penetrameter) hole is so small, it can be difficult to distinguish from noise. It is suspected that an operator’s knowledge of the true location of the 1T hole may subconsciously influence a false positive identification of the 1T hole when in fact it cannot be discerned. In the case of computed radiography (CR), the size of the phosphor particles may lead to a noise pattern with features on the scale of the 1T hole. Per NASA-STD-5009, the 1T hole must be detected in order to achieve adequate sensitivity. This is based on the historical understanding that this sensitivity will enable detection of the minimum detectable flaw sizes listed in the standard. It’s important to understand if 1T sensitivity is being achieved, and the associated risk if not. This study sought to determine the true detectability of 1T-sized holes in aluminum and Inconel by creating and inspecting a set of penetrameters with randomly placed holes. Enough holes and vacant zones were created to enable a full probability of detection study with 90% detectability, 95% confidence. Testing is ongoing, but preliminary results have shown poor detectability. The detection rate is slightly better for Inconel than aluminum, slightly better using a micro-focus vs. mini-focus tube, and definitively better for film than CR. One of the key questions of this study is whether historical requirements for film are applicable for CR, and these initial findings suggest they may not be. There is also a requirement in the NASA standard for the minimum contrast-to-noise ratio of the hole. The results have shown that this numerical threshold does not correlate well with visual detection. This raises questions about the true nature of detection, in an age of image processing vs. human judgement. As the results indicate that the detection of 1T holes is unreliable, the next challenge will be determining what sensitivity is really achieved, and what is needed.

Erin Lanigan↗
NASA NTRSDate not supplied

Development of Radioluminescent Tritium Polymeric Material for High Visibility Applications

The Development of Radioluminescent Tritium Polymeric Material for High Visibility Applications effort investigates the nature and properties of materials consisting of tritium lights combined with various silicone adhesives. Physical, mechanical, and optical properties will be observed/measured, including their durability in the low earth orbit environment. Tritium or hydrogen-three is a radioactive isotope of hydrogen that emits beta particles as it undergoes a process called beta decay. A beta particle is a high-energy, high-speed electron (or positron) emitted from radioactive decay of an atomic nucleus. Because it is a gas, tritium must be bound to a material or encapsulated in a sealed glass container. The gaseous tritium can then be combined with a phosphor source which when struck with beta particles, fluoresces and emits light. Such a light source is referred to as a gaseous tritium light source (GTLS). A self-powered, radioluminescent tritium material capable of surviving multiple space environments has the potential to fulfill visibility requirements levied on space flight hardware and facilitate additional long term internal and external lighting needs such as for imaging, docking, tracking, and xEMU suits for lunar exploration on the moon.

Lauren Fisher↗
NASA NTRS2024

Distributed Sand-Grain Roughness Effects on Blunt Body Hypersonic Transition and Heating

An experimental investigation of distributed sand-grain surface roughness effects on boundary-layer transition and convective heating has been performed. Two representative entry vehicle geometries, a spherical-cap aeroshell and a sphere-cone aeroshell, were considered. Multiple cast ceramic wind tunnel models of each geometry were fabricated with various roughness heights to simulate an ablated thermal protection system. Wind tunnel testing was performed at Mach 6 over a range of Reynolds numbers sufficient to produce laminar, transitional, and turbulent flow. Aeroheating and boundary-layer transition onset data were obtained using global phosphor thermography. The experimental heating data are presented herein, as are comparisons to laminar and turbulent smooth-wall heat transfer distributions from computational flow field simulations.

Brian R. Hollis↗
NASA NTRS2024

Experimental and Computational Study of Convective Heating on the Aeroshell Back Side and Payload of the LOFTID Vehicle

A wind tunnel test program was conducted to obtain experimental convective heating data on models of the Low Earth Orbital Flight Test of an Inflatable Decelerator (LOFTID) vehicle in support of the flight test program. Wind tunnel testing was conducted at Mach 6 and Mach 10 at unit Reynolds numbers from 0.5×106/ft to 4.0×106/ft on 6.0inch diameter aeroshell models. Global heating data were obtained through phosphor thermography measurements on the front and back of the aeroshell and on the payload. For all test conditions, attached, laminar flow was definitively produced on the front of the aeroshell, while in the wake the flow was separated, unsteady and possibly transitional or turbulent. A complementary computational study was performed to assess the accuracy of heating predictions for LOFTID wake flow environments. A new grid topology was developed for the study to allow the use of structured grid solvers for complex, open-backed geometries such as that of LOFTID. Close agreement between measurements and predictions was obtained on the front of the aeroshell. Comparisons were more challenging in the wake because of both the extremely low heating rates and the accompanying high uncertainties and the unsteady nature of the separated wake flow simulations. While the differences between heating predictions and measurements for the wake flow were higher than for the forebody flow, these differences were used to assist in the definition of conservative uncertainty margins for predictions of the flight environments for the successful flight test of the LOFTID vehicle in November 2022.

LOFTID↗
DOE OSTI2020

Proton exchange membrane fuel cells

Disclosed embodiments concern a membrane electrode assembly or a proton exchange membrane fuel cell comprising a phosphoric acid-doped polymeric membrane comprising a cationic functional group, such as an assembly or fuel cell having an ion exchange capacity of 0.8 to 3 mmol/gram and an operating temperature range of from 80° C. to 220° C. The cationic functional group can be any suitable functional group, such as ammonium, imidazolium, guanidinium, phosphazenium, sulfonium, oxonium, and phosphonium, with working embodiments typically using quaternary ammonium cationic functional groups tethered to the polymeric core. The polymeric material may be any suitable polymeric material, such as a material selected from polyaryl polymers, polyarylamides, polyimides, polystyrenes, polysulfones, polyethers, polyether sulfones, polyketones, polyetherketones, polyarylethers, polyolefins, and polynitriles. The membrane electrode assembly or a proton exchange membrane fuel cell can be used in any application now known or hereafter developed, such as a vehicle or a stationary power device.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2020

Readying for a Color-Mixed Future Luminous Efficacy on the Horizon

If history repeats itself, lighting 20 years from now will be substantially different than what it is today. Twenty years ago, LEDs were a novelty, not quite ready for use in architectural lighting systems. A little more than 20 years before that, rare-earth tri-phosphor T8 fluorescent lamps were beginning to replace broadband halophosphate T12 fluorescent lamps, which themselves became the predominant source of lumens in the United States around the middle of the last century. At each step in this evolution, new lighting metrics have been developed to address differences in performance, and they in turn guided technology development. For example, in the 1960s, it was CRI and CCT, and more recently it has been LM-79 and TM-30.

Royer, Michael P.↗
DOE OSTI2020

STRUCTURE AND PROPERTIES STUDY ON ENERGY MATERIALS: THERMOELECTRIC MATERIAL TETRAHEDRITE AND LITHIUM ION CONDUCTOR

Development of efficient energy materials is critical in order to ease the energy demand and reduce our dependence of fossil fuel. Thermoelectric materials are promising due to their capability of generating electrical power by recovering waste heat. The performance of thermoelectric materials is quantified by a dimensionless figure of merit zT, which depends on their properties such as electrical conductivity, Seebeck coefficient and thermal conductivity. Tetrahedrites, a copper antimony sulfosalt mineral, typified by Cu 12-x MxSb 4 S 13 , where M is a transition metal element such as Ni, Zn, Fe or Mn, have great potential for thermoelectric application due to their relatively high zT (close to 1 at 700 K), earth-abundance, environmental friendliness, favorable electrical properties, and most importantly intrinsic low lattice thermal conductivity (less than 1 W m -1 K -1 ) in wide temperature. In addition to energy recovery, reliable energy storage devices are also emerging to relieve the energy demand and improve the efficiency of consuming energy resources. Lithium-ion batteries are known to be reliable and successful electrochemical energy storage devices and appliable in various aspects, including laptops, smartphones and electrical vehicles. Lithium phosphorous oxynitride (LiPON) are widely used as thin-film solid-state electrolytes in Li-ion battery, which is the only demonstrated solid-state electrolyte that is quite stable in direct contact with Li metal at potentials from 0-5 V. However, the structure of LiPON, the effects of N doping, and the origin of its good electrochemical stability remains inconclusive. In this thesis, reliable modeling techniques accompanied with experimental tools, are applied to study the thermoelectric material tetrahedrite and the ionic conductor LiPON, in order to study their structural and dynamical properties. Accurate and efficient density-functional theory (DFT) and density-functional tight-binding (DFTB) methods, combined with molecular dynamics (MD) simulations are utilized in order to investigate the structures and properties of these energy materials. The incoherent and coherent atomic dynamics study of tetrahedrite Cu 10.5 NiZn 0.5 Sb 4 S 13 provides the origin of softening upon cooling by investigate the motion of Cu12e at different temperatures. The dynamic structure factors in the longitudinal and transverse direction will also be discussed. The Cu movement of Cu-rich tetrahedrite Cu 14 Sb 4 S 13 is revealed by Cu self-diffusivity, nuclear density map and “nudged elastic band” (NEB). Moreover, we investigate the effect of simulation cell size and basis sets on the DFT-based MD simulation results using tetrahedrite Cu1 0 Zn 2 Sb 4 S 13 thermoelectric as a model material, showing the advantage of larger cell by accessing smaller Q range. In addition, the low-temperature structural properties of Cu 12 Sb 4 S 13 is measured by neutron diffraction, which indicates that no cubic to tetragonal transition occurs at metal-semiconductor transition (MST) temperature. Thermoelectric properties such as Seebeck coefficient, electrical resistivity and electrical thermal conductivity will also be investigated. DFTB method is implemented to study the structure and transport properties of Li 3 PO 4 and LiPON, while the exploration of N doping effect is included. Lastly, the LiPON/Li interphase will be revealed in order to study the origin of electrochemical stability.

Li, Junchao↗
DOE OSTI2020

STRUCTURE AND PROPERTIES STUDY ON ENERGY MATERIALS: THERMOELECTRIC MATERIAL TETRAHEDRITE AND LITHIUM ION CONDUCTOR LiPON

Development of efficient energy materials is critical in order to ease the energy demand and reduce our dependence of fossil fuel. Thermoelectric materials are promising due to their capability of generating electrical power by recovering waste heat. The performance of thermoelectric materials is quantified by a dimensionless figure of merit zT, which depends on their properties such as electrical conductivity, Seebeck coefficient and thermal conductivity. Tetrahedrites, a copper antimony sulfosalt mineral, typified by Cu12-xMxSb4S13, where M is a transition metal element such as Ni, Zn, Fe or Mn, have great potential for thermoelectric application due to their relatively high zT (close to 1 at 700 K), earth-abundance, environmental friendliness, favorable electrical properties, and most importantly intrinsic low lattice thermal conductivity (less than 1 W m-1 K-1) in wide temperature. In addition to energy recovery, reliable energy storage devices are also emerging to relieve the energy demand and improve the efficiency of consuming energy resources. Lithium-ion batteries are known to be reliable and successful electrochemical energy storage devices and appliable in various aspects, including laptops, smartphones and electrical vehicles. Lithium phosphorous oxynitride (LiPON) are widely used as thin-film solid-state electrolytes in Li-ion battery, which is the only demonstrated solid-state electrolyte that is quite stable in direct contact with Li metal at potentials from 0-5 V. However, the structure of LiPON, the effects of N doping, and the origin of its good electrochemical stability remains inconclusive.In this thesis, reliable modeling techniques accompanied with experimental tools, are applied to study the thermoelectric material tetrahedrite and the ionic conductor LiPON, in order to study their structural and dynamical properties. Accurate and efficient density-functional theory (DFT) and density-functional tight-binding (DFTB) methods, combined with molecular dynamics (MD) simulations are utilized in order to investigate the structures and properties of these energy materials. The incoherent and coherent atomic dynamics study of tetrahedrite Cu10.5NiZn0.5Sb4S13 provides the origin of softening upon cooling by investigate the motion of Cu12e at different temperatures. The dynamic structure factors in the longitudinal and transverse direction will also be discussed. The Cu movement of Cu-rich tetrahedrite Cu14Sb4S13 is revealed by Cu self-diffusivity, nuclear density map and "nudged elastic band" (NEB). Moreover, we investigate the effect of simulation cell size and basis sets on the DFT-based MD simulation results using tetrahedrite Cu10Zn2Sb4S13 thermoelectric as a model material, showing the advantage of larger cell by accessing smaller Q range. In addition, the low-temperature structural properties of Cu12Sb4S13 is measured by neutron diffraction, which indicates that no cubic to tetragonal transition occurs at metal-semiconductor transition (MST) temperature. Thermoelectric properties such as Seebeck coefficient, electrical resistivity and electrical thermal conductivity will also be investigated. DFTB method is implemented to study the structure and transport properties of Li3PO4 and LiPON, while the exploration of N doping effect is included. Lastly, the LiPON/Li interphase will be revealed in order to study the origin of electrochemical stability

25 ENERGY STORAGE↗
DOE OSTI2021

Polyamine phosphorus dendrimer materials for carbon dioxide capture

The present disclosure provides novel solid sorbents synthesized by the reaction of polyamines with polyaldehyde phosphorous dendrimer (P-dendrimer) compounds. The sorbents are highly stable and exhibit rapid reaction kinetics with carbon dioxide, making the sorbents applicable for carbon capture, and can be easily regenerated for further use. The material is stable to aqueous and organic media, as well as strong acid and bases. The sorbent maintains full capacity over extended use. The material can be used for CO2 capture from pure CO2 streams, mixed gas streams, simulated flue gas, and ambient air. Additionally, the material can be adhered to surfaces for reversible CO2 capture applications outside of bulk particle-based processes.

Thompson, III, Samuel John↗
DOE OSTI2021

Polymer compositions and methods

The present invention encompasses polymer compositions comprising aliphatic polycarbonate chains containing functional groups that increase the polymer's ability to wet or adhere to inorganic materials. In certain embodiments, chain ends of the aliphatic polycarbonates are modified to introduce silicon-containing functional groups, boron-containing functional groups, phosphorous-containing functional groups, sulfonic acid groups or carboxylic acid groups.

Allen, Scott D.↗
DOE OSTI2021

High resistivity iron-based, thermally stable magnetic material for on-chip integrated inductors

An on-chip magnetic structure includes a palladium activated seed layer and a substantially amorphous magnetic material disposed onto the palladium activated seed layer. The substantially amorphous magnetic material includes nickel in a range from about 50 to about 80 atomic % (at. %) based on the total number of atoms of the magnetic material, iron in a range from about 10 to about 50 at. % based on the total number of atoms of the magnetic material, and phosphorous in a range from about 0.1 to about 30 at. % based on the total number of atoms of the magnetic material. The magnetic material can include boron in a range from about 0.1 to about 5 at. % based on the total number of atoms of the magnetic material.

Deligianni, Hariklia↗
DOE OSTI2022

Rare-earth doped thermal barrier coating bond coat for thermally grown oxide luminescence sensing

A thermal barrier coated component, such as a turbine blade formed from a superalloy substrate, includes a thermal barrier coating applied onto the substrate. A metallic bond coat layer is on the substrate and includes rare-earth luminescent dopants. A ceramic top coat layer is on the bond coat layer. A temperature sensing thermally grown oxide (TGO) layer is formed at the interface of the bond coat layer and ceramic top coat layer. The temperature sensing TGO layer includes grown rare-earth luminescent ions migrated from the metallic bond coat layer in an amount sufficient to enable luminescence sensing of the TGO layer for real-time phosphor thermometry temperature measurements at the TGO layer.

Fouliard, Quentin↗
DOE OSTI2022

High performance earth-abundant electrocatalysts for hydrogen evolution reaction and other reactions

Electrodes for catalyzing electrochemical reactions (e.g., the hydrogen evolution reaction) are provided. The electrode may comprise a ternary pyrite-phase transition metal phosphochalcogenide (e.g., CoPS) disposed on a substrate, wherein the ternary pyrite-phase transition metal phosphochalcogenide is a solid material of a ternary compound of a transition metal, phosphorous (P), and a chalcogen, the solid material characterized by a substantially single, ternary alloy phase having a pyrite crystal structure. Methods of using and making the electrodes are also provided.

Jin, Song↗
DOE OSTI2023

Method for forming a temperature sensing layer within a thermal barrier coating

A thermal barrier coated component, such as a turbine blade formed from a superalloy substrate, includes a thermal barrier coating applied onto the substrate. A metallic bond coat layer is on the substrate and includes rare-earth luminescent dopants. A ceramic top coat layer is on the bond coat layer. A temperature sensing thermally grown oxide (TGO) layer is formed at the interface of the bond coat layer and ceramic top coat layer. The temperature sensing TGO layer includes grown rare-earth luminescent ions migrated from the metallic bond coat layer in an amount sufficient to enable luminescence sensing of the TGO layer for real-time phosphor thermometry temperature measurements at the TGO layer.

Fouliard, Quentin↗
DOE OSTI2023

Symbiont for enhancement of plant performance

The present disclosure provides an endophyte, Serendipita vermifera ssp. bescii (“S. bescii”), uses thereof and methods incorporating the use thereof for enhancement of plant performance, particularly the use of S. bescii with phosphite as a phosphorous source. The present disclosure also provides methods for detecting the presence of and identifying S. bescii.

Craven, Kelly↗
DOE OSTI2023

Metal complexes and methods of making the same

Disclosed herein are embodiments of metal complexes and methods of making the same. The disclosed method embodiments provide a one-step approach to making metal complexes, such as complexes comprising lanthanide metals, rare earth metals, transition metals, main group metals, and/or actinide metals that can be used various applications, such as in separations technology, catalysis (e.g., catalysts for pharmaceutical synthesis and/or catalysts for biomass conversion), nuclear chemistry, LED phosphors, scintillator materials, magnetic materials, and nuclear fuels.

Kiplinger, Jaqueline↗