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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 1,225 records · Page 68
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Extremely Low Resource Optical Identifier: A License Plate for Your Satellite

Space object identification is vital for operating spacecraft, space traffic control, and space situational awareness, but initial determination, maintenance, and recovery of identity are all difficult, expensive, and error prone, especially for small objects like CubeSats. Attaching a beacon or license plate with a unique identification number to a space object before launch would greatly simplify the task, but radio beacons are power hungry and can cause interference. This work describes a new concept for a satellite license plate: the extremely low resource optical identifier. The extremely low resource optical identifier is a milliwatt-scale self-powered autonomous optical beacon that can be attached to any space object to transmit a persistent identification signal to ground stations. A system appropriate for a low-Earth-orbit CubeSat or other small space object can fit in a package with the area of a postage stamp and a few millimeters thick; and it requires no power, data, or control from the host object. The concept has been validated with ground tests, and the first flight-test unit is scheduled for launch in 2018. The unique identification number of a low-Earth-orbit satellite can be determined unambiguously in a single orbital pass over a low-cost ground station.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1963

Earth Reflected Solar Radiation Incident upon an Arbitrarily Oriented Spinning Flat Plate

A general derivation is given for the earth reflected solar radiation input to a flat plate--a solar cell paddle, for example--which is spinning about an axis coincident with the axis of symmetry of the satellite to which it is affixed. The resulting equations are written for the general case so that arbitrary orientations of the spin axis with respect to the earth-satellite line and arbitrary orientations of the normal to the plate with respect to the spin axis can be treated. No attempt is made to perform the resulting integrations because of the complexity of the equations; nor is there any attempt to delineate the integration limits for the general case. However, the equations governing these limits are given. The appendixes contain: the results, in graphical form, of two representative examples; the general computer program for the calculation is given in Fortran notation; and the results of a calculation of the distribution of albedo energy on the proposed Echo II satellite. The value of the mean solar constant used is 1.395 times 10 (sup 4) ergs per centimeters-squared per second; the mean albedo of the earth is assumed to be 0.34; and the earth is assumed to be a diffuse reflector.

SOLAR RADIATION↗
NASA NTRS1966

Nonlinear oscillations of a fluttering plate.

Two- and three-dimensional plates in high supersonic flow undergoing limit cycle oscillations analyzed, using aerodynamic theory and von Karman large deflection plate theory

PLATE THEORY↗
NASA NTRS1948

Compressive buckling of flat rectangular plates supported by rigid posts

Results of a theoretical investigation of the compressive buckling of flat, rectangular, simply supported plates supported in the interior by equally spaced rows of rigid posts are presented. It is found that the plates buckle as if simply supported along all of the transverse lines or else all of the longitudinal lines passing through the rigid posts, the occurrence of the one buckling mode or the other depending on the number and spacing of the posts.

LOADS AND STRESSES, STRUCTURAL - COMPRESSION↗
NASA NTRS1950

The solution of the laminar-boundary-layer equation for the flat plate for velocity and temperature fields for variable physical properties and for the diffusion field at high concentration

In connection with Pohlhausen's solution for the temperature field on the flat plate, a series of formulas were indicated by means of which the velocity and temperature field for variable physical characteristics can be computed by an integral equation and an iteration method based on it. With it, the following cases were solved: On the assumption that the viscosity simply varies with the temperature while the other fluid properties remain constant, the velocity and temperature field on the heated and cooled plate, respectively, was computed at the Prandtl numbers 12.5 and 100 (viscous fluids). A closer study of these two cases resulted in general relations: The calculations for a gas of Pr number 0.7 (air) were conducted on the assumption that all fluid properties vary with the temperature, and the velocities are low enough for the heat of friction to be discounted. The result was a thickening of the boundary layers, but no appreciable modification in shearing stress or heat-transfer coefficient.

BOUNDARY LAYER, LAMINAR - PLATES, FLAT↗
NASA NTRS2002

NEPTUNE: an under-sea plate scale observatory

The NEPTUNE project will establish a linked array of undersea observatories on the Juan de Fuca tectonic plate. This observatory will provide a new kind of research platform for real-time, long-term, plate-scale studies in the ocean and Earth sciences.

shore station backbone↗
NASA NTRS2016

A Statistical Analysis of the Accuracy of the Digitized Magnitudes of Photometric Plates on the Timescale of Decades with an Application to the Century-Long Light Curve of KIC 8462852

We present a statistical analysis of the accuracy of the digitized magnitudes of photometric plates on the timescale of decades. In our examination of archival Johnson B photometry from the Harvard DASCH archive, we find a median rt mean square scatter of light curves of the order of 0.15 magnitude over the range B approximately equal to 9-17 for all calibrations. Slight underlying systematics (trends or flux discontinuities) are on a level of less than or equal to 0.2 magnitudes per century (1889–1990) for the majority of constant stars. These historic data can be unambiguously used for processes that happen on scales of magnitudes, and need to be carefully examined in cases approaching the noise floor. The characterization of these limits in photometric stability may guide future studies in their use of plate archives. We explain these limitations for the example case of KIC 8462852, which has been claimed to dim by 0.16 magnitudes per century, and show that this trend cannot be considered as significant.

digitized magnitudes of photometric plates↗
NASA NTRS2023

Evaluation of Through-thickness Microtextural Characteristics in 2219-T87 Thick Plate

The objective of this investigation was to establish whether crystallographic texture played a role in variable ST ductility in 2219-T87 thick plate. The EBSD study involved data collection at NASA Glenn Research Center and ODF analysis of the imported data at NASA Langley Research Center. The most significant result was that through-thickness variations in microtextural characteristics were asymmetrical about the mid-plane of the plate. However, the overall texture intensity was low, such that cross-sectional variations were classified as a second order effect on ST ductility.

Aluminum alloy↗
DOE OSTI2025

SPC-70804 Rev 1 Zircar ZAL-45 Alumina Standoff Plates for Use in MARVEL

Idaho National Laboratory (INL) is developing a microreactor to produce electrical power utilizing a small nuclear core and Stirling engines under the Microreactor Application Research Validation and Evaluation (MARVEL) program. This procurement specification defines the requirements for fabrication of the MARVEL ZAL-45 standoff plates manufactured by Zircar. The design requires eight (8) ceramic standoff plates; however, the requested quantity shall be twelve to account for required testing after receipt of materials. Any conflict between this specification and referenced Codes and Standards, or any supplementary specifications in the procurement documents requires written clarification from the Contractor prior to proceeding with any work. Any deviation from the procurement documents requires approval by the Contractor with the change request process.

21 - SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLAN↗
DOE OSTI2015

Evidence for long-lived subduction of an ancient tectonic plate beneath the southern Indian Ocean: Ancient Slab Beneath the Indian Ocean

In this study, ancient subducted tectonic plates have been observed in past seismic images of the mantle beneath North America and Eurasia, and it is likely that other ancient slab structures have remained largely hidden, particularly in the seismic-data-limited regions beneath the vast oceans in the Southern Hemisphere. Here we present a new global tomographic image, which shows a slab-like structure beneath the southern Indian Ocean with coherency from the upper mantle to the core-mantle boundary region—a feature that has never been identified. We postulate that the structure is an ancient tectonic plate that sank into the mantle along an extensive intraoceanic subduction zone that migrated southwestward across the ancient Tethys Ocean in the Mesozoic Era. Slab material still trapped in the transition zone is positioned near the edge of East Gondwana at 140 Ma suggesting that subduction terminated near the margin of the ancient continent prior to breakup and subsequent dispersal of its subcontinents.

58 GEOSCIENCES↗
DOE OSTI2025

Chemo‐Mechanics Interplay Dictates Interface Instability and Asymmetry in Plating and Stripping of Sodium Metal Electrodes

Abstract The development of practical sodium (Na) metal batteries is hindered by key challenges including dendrite growth, dead metal formation, and unstable solid electrolyte interphase (SEI) growth. A fundamental understanding of the chemo‐mechanical interactions at the Na/SEI interface is critical for designing stable Na metal electrodes. In this work, the coupled electrochemical‐mechanical processes governing the morphological evolution and stability of Na metal during plating and stripping are investigated. The heterogeneous nature of transport and morphological interactions at the Na/SEI interface is revealed to result in nonuniform mechanical overpotentials and reaction fronts, eventually leading to Na filaments or pits. The spatio‐temporal evolution of stress heterogeneities during Na plating and stripping is shown to be asymmetric, manifesting in varying morphological nonuniformities and instability modes. The crucial role of external pressure in modulating the electrochemical‐transport interactions, the mechanical response of Na, and the localized reaction currents and stresses at the Na/SEI interface is demonstrated. At different external pressure conditions, the correlation between transport heterogeneities in the SEI and the onset and propagation of interface instability has been delineated. This work highlights the need for synergistic tailoring of external pressure and SEI heterogeneity toward achieving stable electrodeposition and dissolution in Na metal electrodes.

Singla, Aditya [School of Mechanical Engineering P↗
DOE OSTI2021

Interfacial Atomistic Mechanisms of Lithium Metal Stripping and Plating in Solid–State Batteries

All-solid-state batteries based on a Li metal anode represent a promising next-generation energy storage system, but are currently limited by low current density and short cycle life. Further research to improve the Li metal anode is impeded by the lack of understanding in its failure mechanisms at lithium–solid interfaces, in particular, the fundamental atomistic processes responsible for interface failure. Here, using large-scale molecular dynamics simulations, the first atomistic modeling study of lithium stripping and plating on a solid electrolyte is performed by explicitly considering key fundamental atomistic processes and interface atomistic structures. In the simulations, the interface failure initiated with the formation of nano-sized pores, and how interface structures, lithium diffusion, adhesion energy, and applied pressure affect interface failure during Li cycling are observed. By systematically varying the parameters of solid-state lithium cells in the simulations, the parameter space of applied pressures and interfacial adhesion energies that inhibit interface failure during cycling are mapped to guide selection of solid-state cells. Furthermore, this study establishes the atomistic modeling for Li stripping and plating, and predicts optimal solid interfaces and new strategies for the future research and development of solid-state Li-metal batteries.

25 ENERGY STORAGE↗
DOE OSTI2018

Pristine or Highly Defective? Understanding the Role of Graphene Structure for Stable Lithium Metal Plating

The role of graphene host structure/chemistry in plating–stripping in lithium metal anodes employed for lithium metal batteries is first examined in this study. Structural and chemical defects are bad, since highly defective graphene promotes unstable solid electrolyte interphase (SEI) growth. This consumes the fluoroethylene carbonate (FEC) additive in the carbonate electrolyte and is correlated with rapid decay in Coulombic efficiency (CE) and formation of filament-like Li dendrites. A unique flow-aided sonication exfoliation method is employed to synthesize “defect-free” graphene (df-G), allowing for a direct performance comparison with conventional reduced graphene oxide (r-GO). At cycle 1, the r-GO is better electrochemically wetted by Li than df-G, indicating that initially it is more lithiophilic. With cycling, the nucleation overpotential with r-GO becomes higher than with df-G, indicating less facile plating reactions. The df-G yields state-of-the-art electrochemical performance, with the post cycled metal surface being relatively smooth and dendrite-free. Conversely, r-GO templates have CE rapidly degrade from the onset, with extensive dendrites after cycling. Severe SEI growth and associated FEC depletion with r-GO are further confirmed by electrochemical impedance analysis and surface science methods. Finally, a new design rule is provided for Li metal templates: An ideal host must be noncatalytic toward SEI formation.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Transient Chemo‐Mechanical Model of Lithium Plating Impacted by External Pressure

Abstract Lithium anodes show great promise in commercial applications, but are hindered by lithium plating and dendrite growth which cause safety concerns during long‐term cell operation. Stack pressure is experimentally observed to improve cell lifetime; however, the relationship between stress and lithium deposition has remained difficult to elucidate. In this work, a transient, 3D, finite‐element model of the evolution of a lithium anode due to stripping and plating is developed. The evolution of a microscale protrusion on the anode surface is tracked over one charge‐discharge cycle with respect to stack pressure and lithium yield strength. Lithium plastic deformation, nonconformal anode‐separator contact, and separator porosity effects are accounted for. Over the course of several hours of stripping/plating, the anode surface evolves to a similar morphology under pressure regardless of the initial conditions due to lithium plastic deformation and hardening. The rate of this evolution highly depends on the applied pressure and assumed lithium yield strength.

25 ENERGY STORAGE↗
DOE OSTI2018

Microstructure and Properties of 5083 Al/1060 Al/AZ31 Composite Plate Fabricated by Explosive Welding

A 5083 Al/1060 Al/AZ31 composite plate was fabricated by explosive welding. The microstructure and properties of the composite plate were investigated after explosive welding. The results showed that all bonding interfaces were wavy interfaces. With an increasing distance from the detonation point, the wavelength and the amplitude also increased. The EDS results indicated that a 5-μm diffusion layer was observed at the 1060 Al/AZ31 layer, including the Mg{sub 2}Al{sub 3} phase. Adiabatic shear bands and twin structures were observed in AZ31. The shear bond strength of the 5083 Al/1060 Al interface was 60 MPa, and the shear bond strength of the 1060 Al/AZ31 interface was 84 MPa.

36 MATERIALS SCIENCE↗