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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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Ferromagnetic resonance and magnetic studies of cores 60009/60010 and 60003 - Compositional and surface-exposure stratigraphy

Ferromagnetic resonance and static magnetic measurements were made on 131 samples from core 60009/60010 and on 40 samples from section 60003 of the Apollo 16 deep drill core. These studies provided depth profiles for composition, in terms of the concentration of FeO, and relative surface exposure age (or maturity), in terms of the values of the specific FMR intensity normalized to the FeO content. For core 60009/60010, the concentration of FeO ranged from about 1.6 wt.% to 5.8 wt.% with a mean value of 4.6 wt.% and the maturity ranged from immature to mature with most of the soils being submature. A systematic decrease in maturity from the lunar surface to a depth of about 12.5 cm was observed in core section 60010. For core section 60003, the concentration of FeO ranged from about 5.2 wt.% to 7.5 wt.% with a mean value of 6.4 wt.% and the maturity ranged from submature to mature with most of the soils being mature.

Morris, R. V.↗
NASA NTRS1982

Effective photodissociation cross sections for molecular oxygen and nitric oxide in the Schumann-Runge bands

Accurate calculations of the atmospheric opacity and the photodissociation rate of molecular oxygen in the Schumann-Runge bands (175-205) are necessary for modeling chemistry in the terrestrial upper atmosphere. The present investigation is concerned with a single simple parameterization of effective cross sections which can be used to calculate both O2 opacity and dissociation rates. Use is made of a zenith angle dependent factor which accounts for variations shown in detailed calculations. The conducted analysis is based on the results of Frederick and Hudson (1980). Attention is given to molecular oxygen effective cross sections and nitric oxide effective cross sections. It is found that the depth of the atmosphere to which solar radiation in the 175-200 nm spectral region penetrates is a sensitive function of the rotational line widths in the Schumann-Runge bands. The oscillator strength for each band measures the cross section integrated over the band while the line width determine how the absorption is distributed in wavenumber.

Allen, M.↗
NASA NTRS1992

Automation of closed environments in space for human comfort and safety

This report culminates the work accomplished during a three year design project on the automation of an Environmental Control and Life Support System (ECLSS) suitable for space travel and colonization. The system would provide a comfortable living environment in space that is fully functional with limited human supervision. A completely automated ECLSS would increase astronaut productivity while contributing to their safety and comfort. The first section of this report, section 1.0, briefly explains the project, its goals, and the scheduling used by the team in meeting these goals. Section 2.0 presents an in-depth look at each of the component subsystems. Each subsection describes the mathematical modeling and computer simulation used to represent that portion of the system. The individual models have been integrated into a complete computer simulation of the CO2 removal process. In section 3.0, the two simulation control schemes are described. The classical control approach uses traditional methods to control the mechanical equipment. The expert control system uses fuzzy logic and artificial intelligence to control the system. By integrating the two control systems with the mathematical computer simulation, the effectiveness of the two schemes can be compared. The results are then used as proof of concept in considering new control schemes for the entire ECLSS. Section 4.0 covers the results and trends observed when the model was subjected to different test situations. These results provide insight into the operating procedures of the model and the different control schemes. The appendix, section 5.0, contains summaries of lectures presented during the past year, homework assignments, and the completed source code used for the computer simulation and control system.

Source record↗
NASA NTRS1984

Analysis of upper mantle structure using wave field continuation of P waves

Wave field continuation theory, which allows transformation of the seismic record section data directly into velocity-depth space, is tested for upper mantle analysis using a large array-recorded data set obtained at the 200-station Caltech-USGS Southern California Seismic Network that is representative of the structure beneath the gulf of California. The method's resolution capability is illustrated by the comparison of the slant stacks and downward continuation of both synthetic and data record sections. It is stressed that when high-quality, densely sampled digital data are available, the technique is easy to implement, provides an inversion which contains all the data in the global format, and produces an objective estimate of depth resolution as a function of ray parameter.

Walck, M. C.↗
NASA NTRS1985

Proton-air and proton-proton cross sections from air shower data

Data on the fluctuations in depth of maximum development of cosmic ray air showers, corrected for the effects of mixed primary composition and shower development fluctuations, yield values of the inelastic proton-air cross section for laboratory energies in the range 10 to the 8th power to 10 to the 10th power GeV. From these values of proton-air cross section, corresponding values of the proton-proton total cross section are derived by means of Glauber theory and geometrical scaling. The resulting values of proton-proton cross section are inconsistent with a well known 1n(2)s extrapolation of ISR data which is consistent with SPS data; they indicate a less rapid rate of increase in the interval 540 sq root of s 100000 GeV.

Linsley, J.↗
NASA NTRS1986

Production of radionuclides in artificial meteorites irradiated isotropically with 600 MeV protons

The understanding of the production of cosmogenic nuclides in small meteorites (R is less than 40 cm) still is not satisfactory. The existing models for the calculation of depth dependent production rates do not distinguish between the different types of nucleons reacting in a meteorite. They rather use general depth dependent particle fluxes to which cross sections have to be adjusted to fit the measured radionuclide concentrations. Some of these models can not even be extended to zero meteorite sizes without logical contradictions. Therefore, a series of three thick target irradiations was started at the 600 MeV proton beam of the CERN isochronuous cyclotron in order to study the interactions of small stony meteorites with galactic protons. The homogeneous 4 pi irradiation technique used provides a realistic meteorite model which allows a direct comparison of the measured depth profiles with those in real meteorites. Moreover, by the simultaneous measurement of thin target production cross sections one can differentiate between the contributions of primary and secondary nucleons over the entire volume of the artificial meteorite.

Michel, R.↗
DOE OSTI2024

Insight of Synthesis of Single Crystal Ni-Rich LiNi 1-x-y Co x Mn y O 2 Cathodes

Single-crystal Ni-rich LiNi 1-x-y Co x Mn y O 2 (NCM) cathodes have garnered widespread attention in the lithium-ion battery community due to their unique advantages in mechanical performance and their ability to minimize interfacial electrochemical side reactions. The synthesis of single-crystal materials with monodisperse and appropriate size, minimal lattice defects, and highly ordered structures is the key for high-performance batteries. However, achieving this goal poses challenges due to the lack of in-depth understanding regarding specific experimental parameters and the solid reaction mechanism during the synthesis process. Further, in this review, the aim is to provide an in-depth analysis of the critical process parameters involved in the synthesis and their impact on crystal morphology, structure, and electrochemical performance. Consequently, the first section focuses on the effect of the precursor morphology, lithium salt, atmosphere, and sintering procedure. In the second section, the study delves into an in-depth discussion of the solid reaction and crystal growth mechanism. Lastly, it is concluded by highlighting the prospects and challenges associated with the synthesis and application of single-crystal Ni-rich NCM cathodes.

25 ENERGY STORAGE↗
DOE OSTI2025

The Pierre Auger Observatory open data

The Pierre Auger Collaboration has embraced the concept of open access to their research data since its foundation, with the aim of giving access to the widest possible community. A gradual process of release began as early as 2007 when 1% of the cosmic-ray data was made public, along with 100% of the space-weather information. In February 2021, a portal was released containing 10% of cosmic-ray data collected by the Pierre Auger Observatory from 2004 to 2018, during the first phase of operation of the Observatory. The Open Data Portal includes detailed documentation about the detection and reconstruction procedures, analysis codes that can be easily used and modified and, additionally, visualization tools. Since then, the Portal has been updated and extended. In 2023, a catalog of the highest-energy cosmic-ray events examined in depth has been included. A specific section dedicated to educational use has been developed with the expectation that these data will be explored by a wide and diverse community, including professional and citizen scientists, and used for educational and outreach initiatives. This paper describes the context, the spirit, and the technical implementation of the release of data by the largest cosmic-ray detector ever built and anticipates its future developments.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2022

Riverbed Temperature and 4D ERT Monitoring Reveals Heterogenous Horizontal and Vertical Groundwater-Surface Water Exchange Flows Under Dynamic Stage Conditions

Groundwater surface water exchange plays a critical role in physical, biological, and geochemical function of coastal and riverine systems. Observing exchange flow behavior in heterogeneous systems is a primary challenge, particularly when flows are governed by dynamic river stage or tidal variations. In this paper we demonstrate a novel application of time-lapse 3D electrical resistivity tomography and temperature monitoring where an array of thermistors installed beneath a riverbed double as resistivity electrodes. We use the array to monitor stage driven exchange flows over a 6-day period in a dynamic, stage-driven high order stream. We present a method for addressing the otherwise confounding effects of the moving river-surface boundary on the raw resistivity data, thereby enabling successful tomographic imaging. Temperature time-series at each thermistor location and time-lapse 3D images of changes in bulk electrical conductivity together provide a detailed description of exchange dynamics over a 10-meter by 45-meter section of the riverbed, to a depth of approximately 5 m. Results reveal highly variable flux behavior throughout the monitoring domain including both horizontal and vertical exchange flows.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1971

Random excitation of a panel-cavity system

An experimental investigation of the influence of random external sound field on cavity pressure and panel vibration is presented. The panel used was 10 in. x 20 in. x 0.05 in. aluminum alloy plate that was bonded onto a rectangular frame consisting of aluminum channel members welded together at their ends. By bonding the plate to the cavity in this way, a clamped edge boundary condition was approximated. A sealed cavity was constructed beneath the panel in such a way that the cavity depth could be varied in 2 in. increments from 12 in. to 2 in. deep. In order to vary the cavity depth, the cavity was built in sections. Each 2 in. section of the cavity was bolted to the other sections with rubber gaskets between them. The panel was excited acoustically by a Wolverine LS15, 20 watt loudspeaker driven by a B and K random noise generator, Type 1402. The external sound field was measured on the panel surface, using the 6 percent bandwidth of the frequency analyzer.

Gorman, G. F., III↗
NASA NTRS1972

Radioactivities in returned lunar materials.

The difference between the Ar-37 activities from similar locations in the rocks 12002 and 15555 provides direct measures of the Ar-37 activities produced by the 2 November 1969 flare. Differences between the Ar-37 activities in 14321 and 15555 give Ar-37 activities produced by the 24 January 1971 flare. The intensities of the two flares were determined by making use of measured Ar-37 cross sections in simulated lunar material. The depth dependence of tritium in samples and its temperature-release pattern provides information about the sources of the tritium and about the intensity of solar flares integrated over the past 30 years.

Fireman, E. L.↗
NASA NTRS1990

Computing Scattering Matrices For Circular Waveguides

Scattering Matrix Program for Circular Waveguide Junctions computes scattering matrix for series of circular waveguide sections. Sections must have same axis, but radius and length of each section completely arbitrary. Devices analyzed include simple waveguide step discontinuity like that used in a dual-mode horn, stepped matching section, or corrugated waveguide section with constant or varying slot depth. Certain types of corrugated horns also analyzed with program. Mathematical model used in program accurately predicts reflection and transmission characteristics of such devices, taking into account excitation of modes of higher order as well as multiple reflections and energy stored at each discontinuity. Written in FORTRAN 77.

Hoppe, Daniel J.↗
NASA NTRS1992

Surface analyses of composites exposed to the space environment on LDEF

We have conducted a series of surface analyses on carbon fiber/polyarylacetylene matrix composites that were exposed to the space environment on the LDEF satellite. None of the composites were catastrophically damaged by nearly six years of exposure to the space environment. Composites on the leading edge exhibited about 5 mils of surface erosion, but trailing edge panels exhibited no physical appearance changes due to exposure. Scanning electron microscopy (SEM) was used to show that the erosion morphology on the leading edge samples was dominated by crevasses parallel to the fibers with triangular cross sections 10 to 100 microns in depth. The edges of the crevasses were well defined and penetrated through both matrix and fiber. The data suggest that the carbon fibers are playing a significant role in crevasse initiation and/or enlargement, and in the overall erosion rate of the composite. X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDS) results showed the presence of silicone and hydrocarbon contamination from in-flight sources. The role of contamination in crevasse initiation and enlargement is unknown at this time. These LDEF results demonstrate that the prediction of long term atomic oxygen erosion morphology for composite materials from erosion data obtained on short Space Shuttle missions is difficult. A better understanding of other factors such as thermal cycling and UV exposure which may influence erosion is necessary to improve the accuracy of the predictions.

Mallon, Joseph J.↗
NASA NTRS1993

Surface analyses of composites exposed to the space environment on LDEF

A series of surface analyses on carbon fiber/poly(arylacetylene) (PAA) matrix composites that were exposed to the space environment on the Long Duration Exposure Facility (LDEF) satellite were conducted. These composite panels were arranged in pairs on both the leading edge and trailing edge of LDEF. None of the composites were catastrophically damaged by nearly six years of exposure to the space environment. Composites on the leading edge exhibited from 25 to 125 microns of surface erosion, but trailing edge panels exhibited no physical appearance changes due to exposure. Scanning electron microscopy (SEM) was used to show that the erosion morphology on the leading edge samples was dominated by crevasses parallel to the fibers with triangular cross sections 10 to 100 microns in depth. The edges of the crevasses were well defined and penetrated through both matrix and fiber. The data suggest that the carbon fibers are playing an important role in crevasse initiation and/or enlargement, and in the overall erosion rate of the composite. X-ray photoelectron spectroscopy (XPS) and energy dispersive x-ray spectroscopy (EDS) results showed contamination from in-flight sources of silicone.

Mallon, Joseph J.↗
NASA NTRS1993

IRTF observations of the occultation of 28 Sgr by Saturn

NASA's Mauna Kea IR Telescope Facility obtained an IR-imaging time series for the July 3, 1989 occultation of 28 Sgr by Saturn and its rings; the stellar signal is present in these images throughout the ring occultation event. These data are noted to vary systematically with respect to the Voyager data over large radius scales, perhaps due to stellar signal diffraction through the rings. The stellar diameter, which is projected to be about 20 km, placed most bending- and density-wave trains below measurable resolution. Masses and mean optical depths are presented for individual ring sections.

Harrington, Joseph↗
NASA NTRS1994

Cosmogenic C-14 in Antarctic and non-Antarctic meteorites and lunar samples

We were able to develop measurements of C-14 in meteorites as a useful tool for estimates of terrestrial age. Prior to this accomplishment, only a few measurements of C-14 terrestrial ages had been made. The sample sizes were larger, and there had been no systematic study of the various parameters affecting production of C-14, such as depth dependence, and the production cross sections for C-14 from spallation amounted to a few data points. Presently, C-14 ages are an accepted terrestrial age estimate in the meteorite community, whereas before this work the few data available were difficult to interpret. We have obtained terrestrial ages not only on groups of meteorites from different geographic areas but also information on unique meteorites from particularly interesting groups, such as meteorites originating from the Moon, or SNC meteorites, which many researchers believe are derived from Mars.

Jull, A. J. Timothy↗
NASA NTRS1995

Simultaneous Extreme-Ultraviolet Explorer and Optical Observations of Ad Leonis: Evidence for Large Coronal Loops and the Neupert Effect in Stellar Flares

We report on the first simultaneous Extreme-Ultraviolet Explorer (EUVE) and optical observations of flares on the dMe flare star AD Leonis. The data show the following features: (1) Two flares (one large and one of moderate size) of several hours duration were observed in the EUV wavelength range; (2) Flare emission observed in the optical precedes the emission seen with EUVE; and (3) Several diminutions (DIMs) in the optical continuum were observed during the period of optical flare activity. To interpret these data, we develop a technique for deriving the coronal loop length from the observed rise and decay behavior of the EUV flare. The technique is generally applicable to existing and future coronal observations of stellar flares. We also determine the pressure, column depth, emission measure, loop cross-sectional area, and peak thermal energy during the two EUV flares, and the temperature, area coverage, and energy of the optical continuum emission. When the optical and coronal data are combined, we find convincing evidence of a stellar 'Neupert effect' which is a strong signature of chromospheric evaporation models. We then argue that the known spatial correlation of white-light emission with hard X-ray emission in solar flares, and the identification of the hard X-ray emission with nonthermal bremsstrahlung produced by accelerated electrons, provides evidence that flare heating on dMe stars is produced by the same electron precipitation mechanism that is inferred to occur on the Sun. We provide a thorough picture of the physical processes that are operative during the largest EUV flare, compare and contrast this picture with the canonical solar flare model, and conclude that the coronal loop length may be the most important factor in determining the flare rise time and energetics.

Hawley, Suzanne L.↗
NASA NTRS1985

Assessment of metabolic bone diseases by quantitative computed tomography

Advances in the radiologic sciences have permitted the development of numerous noninvasive techniques for measuring the mineral content of bone, with varying degrees of precision, accuracy, and sensitivity. The techniques of standard radiography, radiogrammetry, photodensitometry, Compton scattering, neutron activation analysis, single and dual photon absorptiometry, and quantitative computed tomography (QCT) are described and reviewed in depth. Results from previous cross-sectional and longitudinal QCT investigations are given. They then describe a current investigation in which they studied 269 subjects, including 173 normal women, 34 patients with hyperparathyroidism, 24 patients with steroid-induced osteoporosis, and 38 men with idiopathic osteoporosis. Spinal quantitative computed tomography, radiogrammetry, and single photon absorptiometry were performed, and a spinal fracture index was calculated on all patients. The authors found a disproportionate loss of spinal trabecular mineral compared to appendicular mineral in the men with idiopathic osteoporosis and the patients with steroid-induced osteoporosis. They observed roughly equivalent mineral loss in both the appendicular and axial regions in the hyperparathyroid patients. The appendicular cortical measurements correlated moderately well with each other but less well with spinal trabecular QCT. The spinal fracture index correlated well with QCT and less well with the appendicular measurements. Knowledge of appendicular cortical mineral status is important in its own right but is not a valid predictor of axial trabecular mineral status, which may be disproportionately decreased in certain diseases. Quantitative CT provides a reliable means of assessing the latter region of the skeleton, correlates well with the spinal fracture index (a semiquantitative measurement of end-organ failure), and offers the clinician a sensitive means of following the effects of therapy.

Minerals/analysis↗