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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 703 records · Page 39
All sourcesNASA NTRSDOE OSTI
NASA NTRS1984

Facular Limb-darkening Functions for Irradiance Modeling

The limb darkening function of faculae is an important factor in estimating facular contributions to solar irradiance variations. The existing photometric data is reviewed and a synthetic limb darkening function for faculae was generated which was compared with the limb darkening functions currently in use for irradiance modeling. The excess facular flux ranges from 0.017 to 0.0349 of the solar photospheric flux for the various representations. The present limitation appears to be the lack of comprehensive photometric data. The representations are especially varied near the limb, where photometry is most difficult. Synoptic data on calcium plage areas is used as a substitute for facular areas in modeling. Based upon the existing data, the present best value for the effect of faculae on the solar constant is given by delta s/s = 3.9 x 10(-8) A (sub plage prime) for an active region near disk center, where A (sub plage) is the calcium plage area in millionths of a solar hemisphere.

Hirayama, T.↗
NASA NTRS1976

Biology on the outer planets

A brief review is given of information on the structure and composition of the outer planets and the organic reactions that may be occurring on them. The possibility of life arising or surviving in the atmospheres of these planets is considered, and the problem of contamination during future unmanned missions is assessed. Atmospheric models or available atmospheric data are reviewed for Jupiter, Saturn, Uranus, Neptune, Pluto, the Galilean satellites, and Titan. The presence of biologically interesting gases on Jupiter and Saturn is discussed, requirements for life on Jupiter are summarized, and possible sources of biological energy are examined. Proposals are made for protecting these planets and satellites from biological contamination by spacecraftborne terrestrial organisms.

Young, R. S.↗
NASA NTRS1990

Emission characteristics of three intense solar flares observed in cycle 21

The available observational data is reviewed, for three solar flares, that occurred on June 21, 1980, June 3, 1982, and April 24, 1984. Inperpretations given prior to the time of this workshop and some interpretations presented at the workshop are considered. A possible common model describing the three flares is also discussed. It is clear that more refined analysis of all available data for these three events is very desirable and could lead to improved understanding of the flare process.

Chupp, Edward L.↗
NASA NTRS1984

Estimation of electric fields and current from ground-based magnetometer data

Recent advances in numerical algorithms for estimating ionospheric electric fields and currents from groundbased magnetometer data are reviewed and evaluated. Tests of the adequacy of one such algorithm in reproducing large-scale patterns of electrodynamic parameters in the high-latitude ionosphere have yielded generally positive results, at least for some simple cases. Some encouraging advances in producing realistic conductivity models, which are a critical input, are pointed out. When the algorithms are applied to extensive data sets, such as the ones from meridian chain magnetometer networks during the IMS, together with refined conductivity models, unique information on instantaneous electric field and current patterns can be obtained. Examples of electric potentials, ionospheric currents, field-aligned currents, and Joule heating distributions derived from ground magnetic data are presented. Possible directions for future improvements are also pointed out.

Kamide, Y.↗
NASA NTRS1992

Two-equation turbulence modeling for 3-D hypersonic flows

An investigation to verify, incorporate and develop two-equation turbulence models for three-dimensional high speed flows is presented. The current design effort of hypersonic vehicles has led to an intensive study of turbulence models for compressible hypersonic flows. This research complements an extensive review of experimental data and the current development of 2D turbulence models. The review of experimental data on 2D and 3D flows includes complex hypersonic flows with pressure profiles, skin friction, wall heat transfer, and turbulence statistics data. In a parallel effort, turbulence models for high speed flows have been tested against flat plate boundary layers, and are being tested against the 2D database. In the present paper, we present the results of 3D Navier-Stokes numerical simulations with an improved k-omega two-equation turbulence model against experimental data and empirical correlations of an adiabatic flat plate boundary layer, a cold wall flat plate boundary layer, and a 3D database flow, the interaction of an oblique shock wave and a thick turbulent boundary layer with a free stream Mach number = 8.18 and Reynolds number = 5 x 10 to the 6th.

Bardina, J. E.↗
NASA NTRS2015

Analysis of Aviation Safety Reporting System Incident Data Associated with the Technical Challenges of the System-Wide Safety and Assurance Technologies Project

The Aviation Safety Program (AvSP) System-Wide Safety and Assurance Technologies (SSAT) Project asked the AvSP Systems and Portfolio Analysis Team to identify SSAT-related trends. SSAT had four technical challenges: advance safety assurance to enable deployment of NextGen systems; automated discovery of precursors to aviation safety incidents; increasing safety of human-automation interaction by incorporating human performance, and prognostic algorithm design for safety assurance. This report reviews incident data from the NASA Aviation Safety Reporting System (ASRS) for system-component-failure- or-malfunction- (SCFM-) related and human-factor-related incidents for commercial or cargo air carriers (Part 121), commuter airlines (Part 135), and general aviation (Part 91). The data was analyzed by Federal Aviation Regulations (FAR) part, phase of flight, SCFM category, human factor category, and a variety of anomalies and results. There were 38 894 SCFM-related incidents and 83 478 human-factorrelated incidents analyzed between January 1993 and April 2011.

Withrow, Colleen A.↗
NASA NTRS1987

The applicability of satellite altimetry data to tidal models

The characteristics of satellite altimetry data are reviewed, and techniques for incorporating them into numerical tide models are discussed. The relationship between the geocentric tides observed by satellites and the ocean tides measured by gages or predicted by models is explored, and particular attention is given to the differences between deep-water, shelf, and estuarine tidal regimes. It is concluded that a separate tidal solution should always be performed before assimilating satellite data, including calculation of the tides along a single repeated ground track in the case of shelf and estuarine regions. The potential value of the altimetry to be provided by Topex/Poseidon (scheduled launch in 1991) is indicated.

Parke, Michael E.↗
NASA NTRS1975

Machine processing of S-192 and supporting aircraft data: Studies of atmospheric effects, agricultural classifications, and land resource mapping

Two tasks of machine processing of S-192 multispectral scanner data are reviewed. In the first task, the effects of changing atmospheric and base altitude on the ability to machine-classify agricultural crops were investigated. A classifier and atmospheric effects simulation model was devised and its accuracy verified by comparison of its predicted results with S-192 processed results. In the second task, land resource maps of a mountainous area near Cripple Creek, Colorado were prepared from S-192 data collected on 4 August 1973.

Thomson, F.↗
NASA NTRS1998

The Role of Viscous Deformation in the Morphology of the Martian North Polar Cap

The first detailed topographic measurements of Mars' north polar cap have recently been collected by the Mars Orbiter Laser Altimeter (MOLA), an instrument on Mars Global Surveyor (MGS). These new data provide the opportunity to address in a quantitative way the processes responsible for the origin and evolution of the martian polar caps. On the basis of imaging and spectral observations from the Mariner 9 and Viking orbiters, it was recognized that a number of physical mechanisms. including radiative transfer, wind erosion, and viscous flow, represent possible or probable contributors to the morphology of the polar cap. Here we review rheological data for H2O and CO2 at conditions relevant to the martian polar regions. We then use MOLA topographic profiles to perform a preliminary assessment of the role of power law flow in contributing to the regional-scale planform of the north polar cap.

Zuber, M. T.↗
NASA NTRS2010

Analysis of Wind Tunnel Polar Replicates Using the Modern Design of Experiments

The role of variance in a Modern Design of Experiments analysis of wind tunnel data is reviewed, with distinctions made between explained and unexplained variance. The partitioning of unexplained variance into systematic and random components is illustrated, with examples of the elusive systematic component provided for various types of real-world tests. The importance of detecting and defending against systematic unexplained variance in wind tunnel testing is discussed, and the random and systematic components of unexplained variance are examined for a representative wind tunnel data set acquired in a test in which a missile is used as a test article. The adverse impact of correlated (non-independent) experimental errors is described, and recommendations are offered for replication strategies that facilitate the quantification of random and systematic unexplained variance.

Deloach, Richard↗
NASA NTRS1972

Noise from interaction of flow with rigid surfaces: A review of current status of prediction techniques

A brief review of some fundamental aspects of sound arising from turbulent boundary layers, noise due to flow past a single discontinuity (trailing edge), noise from airfoils operating in turbulent flow, and noise due to rigid flow discontinuities (spoilers) immersed in rigid ducts is presented. Emphasis is on dipole-like sound fields associated with turbulent flow past a trailing edge, rigid bodies in turbulence and in-duct spoilers. Representative available data are reviewed and evaluated in terms of theoretical considerations and, where possible, empirical prediction techniques are given in terms of convenient aerodynamic and geometric parameters. Limitations on current knowledge are discussed.

Hayden, R. E.↗
NASA NTRS2004

Heavy particle irradiation, neurochemistry and behavior: thresholds, dose-response curves and recovery of function

Exposure to heavy particles can affect the functioning of the central nervous system (CNS), particularly the dopaminergic system. In turn, the radiation-induced disruption of dopaminergic function affects a variety of behaviors that are dependent upon the integrity of this system, including motor behavior (upper body strength), amphetamine (dopamine)-mediated taste aversion learning, and operant conditioning (fixed-ratio bar pressing). Although the relationships between heavy particle irradiation and the effects of exposure depend, to some extent, upon the specific behavioral or neurochemical endpoint under consideration, a review of the available research leads to the hypothesis that the endpoints mediated by the CNS have certain characteristics in common. These include: (1) a threshold, below which there is no apparent effect; (2) the lack of a dose-response relationship, or an extremely steep dose-response curve, depending on the particular endpoint; and (3) the absence of recovery of function, such that the heavy particle-induced behavioral and neural changes are present when tested up to one year following exposure. The current report reviews the data relevant to the degree to which these characteristics are common to neurochemical and behavioral endpoints that are mediated by the effects of exposure to heavy particles on CNS activity. c2004 COSPAR. Published by Elsevier Ltd. All rights reserved.

Review↗
DOE OSTI2026

Human Factors Considerations for Hydrogen Rail Refueling and Maintenance

The Federal Railroad Administration (FRA) contracted Sandia National Laboratories to review the risks introduced specifically through human interactions within hydrogen rail refueling and maintenance activities and present recommendations for future system development and implementation. Due to the lack of domestic hydrogen-powered trains at the time of review, observational data was collected on analogous existing systems to consider various ways hydrogen might be implemented within future designs. The team developed 50 human factors design guidelines through analysis of human risk factors. Because hydrogen rail systems are still in the early design stage, the resulting human factors guidelines represent general best practices and do not include specific design features. The research team recommends design and regulatory agencies include a Human Factors Engineer in the design and review process to ensure the guidelines are appropriately implemented and verified.

08 HYDROGEN↗
NASA NTRS1981

Analytical techniques for the analysis of stall/spin flight test data

Analytical techniques for the analysis of stall/spin flight test data are reviewed by discussing (1) certain special flight instrumentation issues, (2) the mathematical modeling techniques, and (3) the analysis of post stall and spinning flight of general aviation airplanes. The angles of attack, sideslip, roll, pitch, and yaw are derived from measurements of angular velocity and linear acceleration. The key to the success of this approach is to simultaneously estimate both the biases in the instrumentation and the initial conditions. Techniques for determining stability derivatives from flight data are applied to angles of attack too high for stabilized flight. This practice greatly expands the range over which aerodynamic characteristics can be determined from flight test. Nonlinear terms in certain aerodynamic functions are shown to be valid by comparing them with the trends of results at different angles of attack. A very old technique of studying spins is extended and applied to some modern light airplanes. Airplanes for which the wing provides the dominant moments during spins, offer the possibility of linking spin characteristics to longitudinal data.

Taylor, L. W., Jr.↗
NASA NTRS2016

Simulation and Flight Test Data Collection to Support Phase 1 Detect-and-Avoid MOPS

The UAS Integration into the NAS (UASNAS) project is studying the minimum operational performance standards for unmanned aerial system (UAS) detect-and-avoid (DAA) systems in order to operate in the National Airspace System (NAS). The project is executing a series of fast-time simulation, human-in-the-loop experiments, and flight tests in support of this effort. Armstrong Flight Research Center is hosting a VIP Day in conjunction with the UAS-NAS Project's Flight Test 4 activity, and the Ames Project Engineer (or designate) will be presenting a briefing. This briefing will review the data collection and analysis activities for Flight Test 4 within the Separation assurance-Sense-and-avoid Interoperability (SSI) team.

data analysis↗
NASA NTRS2003

On the Utilization of In-flight Radiation-induced Performance Data and Anomaly Resolution of Commercial Off the Shelf (COTS) Electronics

This viewgraph presentation presents an overview of the use of in-flight science data to review the radiation effects on commercial off the shelf (COTS) electronics used in recent spacecraft missions. The authors review the hazards that the space radiation environment pose for spacecraft electronics. They specifically discuss long term effects such as total ionizing dose (TID) and short term effects like single particle events (SEE). The advantages of using COTS electronics despite not being radiation hardened are mentioned. The reasons cite for tracking in-flight performance of COTS electronics include: anomaly resolution, validate ground tests and environmental predictions and provide lessons for future designers. Sample radiation impacts of science data from the following missions are analyzed: SOHO/LASCO 3 Coronograph, Microwave Anisotrophy Probe, Hubble Space Telescope and Chandra X-Ray Observatory.

Kenneth A. LeBel↗
DOE OSTI2022

Kronecker-structured covariance models for multiway data

Many applications produce multiway data of exceedingly high dimension. Modeling such multi-way data is important in multichannel signal and video processing where sensors produce multi-indexed data, e.g. over spatial, frequency, and temporal dimensions. We will address the challenges of covariance representation of multiway data and review some of the progress in statistical modeling of multiway covariance over the past two decades, focusing on tensor-valued covariance models and their inference. We will illustrate through a space weather application: predicting the evolution of solar active regions over time.

97 MATHEMATICS AND COMPUTING↗
NASA NTRS1987

Cross-modal interference and task integration - Resources or preemption switching?

Data are reviewed from experiments that have contrasted intra-modal (visual-visual) information presentation with cross-modal (visual-auditory) presentation. Five different processing mechanisms that are operating in dual stimulus tasks are described, and it is concluded that in studies where visual scanning is not required, cross-modal effects are of two classes. When the visual task is continuous (tracking), a discrete auditory stimulus will preempt tracking performance relative to a discrete visual stimulus, leading to an effective shift in allocation bias. When both tasks are discrete, the data regarding the relative advantages of cross- vs. intra-modal interference are ambivalent.

Wickens, Christopher D.↗