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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 343 records · Page 19

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NASA NTRS1988

Nature and interpretation of fluid inclusions in granulites

Many granulites contain CO2 rich high density fluid inclusions (carbonic fluids). This observation has led to the concept of carbonic metamorphism, the dry character of granulites being less explained by the absence of water (vapor absent metamorphism) than by the presence of a CO2-rich fluid phase which dilutes the water and lowers considerably its partial pressure. Recent observations have indicated that the situation is much more complicated than initially assumed and that any interpretation must be carefully evaluated and discussed against other, independent evidence. The nature of fluid inclusions and the interpretation of fluid inclusion densities are discussed.

Touret, Jacques L. R.↗

NASA NTRS1988

Dynamical interpretation of conditional patterns

While great progress is being made in characterizing the 3-D structure of organized turbulent motions using conditional averaging analysis, there is a lack of theoretical guidance regarding the interpretation and utilization of such information. Questions concerning the significance of the structures, their contributions to various transport properties, and their dynamics cannot be answered without recourse to appropriate dynamical governing equations. One approach which addresses some of these questions uses the conditional fields as initial conditions and calculates their evolution from the Navier-Stokes equations, yielding valuable information about stability, growth, and longevity of the mean structure. To interpret statistical aspects of the structures, a different type of theory which deals with the structures in the context of their contributions to the statistics of the flow is needed. As a first step toward this end, an effort was made to integrate the structural information from the study of organized structures with a suitable statistical theory. This is done by stochastically estimating the two-point conditional averages that appear in the equation for the one-point probability density function, and relating the structures to the conditional stresses. Salient features of the estimates are identified, and the structure of the one-point estimates in channel flow is defined.

Adrian, R. J.↗

NASA NTRS1988

On the interpretation of integrated water vapor patterns in midlatitude cyclones derived from the Nimbus 7 scanning multichannel microwave radiometer

The present exploration of methods for the interpretation of the Nimbus 7 satellite's Scanning Multichannel Microwave Radiometer (SMMR) vapor patterns and the ways in which they relate to the dynamical structure of individual midlatitude storms employs gridded meteorological data from the First GARP Global Experiment special observing period in order to calculate diagnostic quantities. SMMR patterns for a storm at a weak stage determined from the diagnostic quantities are compared with SMMR patterns for the storm at a stronger stage. A more complete interpretation of the SMMR patterns emerges from these considerations.

Mcmurdie, Lynn A.↗

NASA NTRS1989

Linear force-free magnetic fields for solar extrapolation and interpretation

This paper discusses the interconnection of the various linear force-free magnetic field formulations, the specific phenomenological and topological parameters of these formulations, and their usefulness. Particularly, the limitations and usefulness of linear force-free fields are discussed. Specific field configurations are related to magnetographic interpretation. The relationship of the integral and Fourier procedures is shown explicitly. The physical interpretation of linear force-free fields is shown by analytic models and from the Marshall Space Flight Center solar vector magnetograms.

Gary, G. Allen↗

NASA NTRS1989

Selective simulation and selective sensor interpretation in monitoring

An approach to selective processing in monitoring is described. The approach is designed to provide informative feedback on whether a system is performing nominally in the current operating context without exceeding available resources for prediction and interpretation. At the center of the approach to selective sensor interpretation and simulation is a causal model of the system being monitored. The architecture of the monitoring system, called PREMON, is described as well as how causal models of physical systems are represented and simulated.

Doyle, Richard J.↗

NASA NTRS1990

Intercomparison and interpretation of climate feedback processes in 19 atmospheric general circulation models

The present study provides an intercomparison and interpretation of climate feedback processes in 19 atmospheric general circulation models. This intercomparison uses sea surface temperature change as a surrogate for climate change. The interpretation of cloud-climate interactions is given special attention. A roughly threefold variation in one measure of global climate sensitivity is found among the 19 models. The important conclusion is that most of this variation is attributable to differences in the models' depiction of cloud feedback, a result that emphasizes the need for improvements in the treatment of clouds in these models if they are ultimately to be used as reliable climate predictors. It is further emphazied that cloud feedback is the consequence of all interacting physical and dynamical processes in a general circulation model. The result of these processes is to produce changes in temperature, moisture distribution, and clouds which are integrated into the radiative response termed cloud feedback.

Cess, R. D.↗

NASA NTRS1990

Generic interpreters and microprocessor verification

The following topics are covered in viewgraph form: (1) generic interpreters; (2) Viper microprocessors; (3) microprocessor verification; (4) determining correctness; (5) hierarchical decomposition; (6) interpreter theory; (7) AVM-1; (8) phase-level specification; and future work.

Windley, Phillip J.↗

NASA NTRS1991

Crustal structure interpreted from magnetic anomalies

This review, discusses publications during the last quadrennium (1987-1990) that used aeromagnetic data, marine magnetic data, satellite magnetic data, and rock magnetic and petrologic data to provide information on the sources of magnetic anomalies. The publications reviewed reflect increased integration of rock magnetic property and petrologic studies with magnetic anomaly interpretation studies, particularly in deep crustal magnetization, exploration for hydrocarbons, and inversion of marine magnetic anomalies. Interpretations of aeromagnetic data featuring image display techniques and using the horizontal gradient method for locating magnetization boundaries became standard.

Phillips, Jeffrey D.↗

NASA NTRS1992

Improved interpretation of satellite altimeter data using genetic algorithms

Genetic algorithms (GA) are optimization techniques that are based on the mechanics of evolution and natural selection. They take advantage of the power of cumulative selection, in which successive incremental improvements in a solution structure become the basis for continued development. A GA is an iterative procedure that maintains a 'population' of 'organisms' (candidate solutions). Through successive 'generations' (iterations) the population as a whole improves in simulation of Darwin's 'survival of the fittest'. GA's have been shown to be successful where noise significantly reduces the ability of other search techniques to work effectively. Satellite altimetry provides useful information about oceanographic phenomena. It provides rapid global coverage of the oceans and is not as severely hampered by cloud cover as infrared imagery. Despite these and other benefits, several factors lead to significant difficulty in interpretation. The GA approach to the improved interpretation of satellite data involves the representation of the ocean surface model as a string of parameters or coefficients from the model. The GA searches in parallel, a population of such representations (organisms) to obtain the individual that is best suited to 'survive', that is, the fittest as measured with respect to some 'fitness' function. The fittest organism is the one that best represents the ocean surface model with respect to the altimeter data.

Messa, Kenneth↗

NASA NTRS1992

Physical interpretation of thermal and reflected data on Martian surface units

None of the available Viking Orbiter Infrared Thermal Mapper's thermal datasets can be uniquely interpreted in isolation from other data in terms of variations of a single, simple physical parameter of the martian surface. Other thermal datasets of a target area, thermal observations of adjacent materials, and visible and near-infrared observations of the same region can often sufficiently constrain interpretations to obtain one that is nearly unique. The major datasets, their derived information, and their ambiguities are given.

Strickland, Edwin L., III↗

NASA NTRS1993

Interpreted Cooper-Harper for broader use

The current aircraft assessment process typically makes extensive use of operational personnel during simulations and operational evaluations, with increased emphasis on evaluating the many pilot and/or operator/aircraft control loops. The need for a crew assessment in this broader arena has produced a variety of rating scales. The Cooper-Harper Rating Scale is frequently misused and routinely overlooked in the process, for these applications often extend the scale's use beyond its originally intended application. This paper agrees with the broader application of the Cooper-Harper Rating Scale and presents a concept for the development of a 'use unique' Interpreted Cooper-Harper Scale to help achieve this objective. This interpreted scale concept was conceived during efforts to support an FAA evaluation of a night vision enhancement system. It includes descriptive extensions, which are faithful to the intent of the current Cooper-Harper Scale and should provide the kind of detail that has historically been provided by trained test pilots in their explanatory comments.

Green, David L.↗

NASA NTRS1994

Control of Wind Tunnel Operations Using Neural Net Interpretation of Flow Visualization Records

Neural net control of operations in a small subsonic/transonic/supersonic wind tunnel at Lewis Research Center is discussed. The tunnel and the layout for neural net control or control by other parallel processing techniques are described. The tunnel is an affordable, multiuser platform for testing instrumentation and components, as well as parallel processing and control strategies. Neural nets have already been tested on archival schlieren and holographic visualizations from this tunnel as well as recent supersonic and transonic shadowgraph. This paper discusses the performance of neural nets for interpreting shadowgraph images in connection with a recent exercise for tuning the tunnel in a subsonic/transonic cascade mode of operation. That mode was operated for performing wake surveys in connection with NASA's Advanced Subsonic Technology (AST) noise reduction program. The shadowgraph was presented to the neural nets as 60 by 60 pixel arrays. The outputs were tunnel parameters such as valve settings or tunnel state identifiers for selected tunnel operating points, conditions, or states. The neural nets were very sensitive, perhaps too sensitive, to shadowgraph pattern detail. However, the nets exhibited good immunity to variations in brightness, to noise, and to changes in contrast. The nets are fast enough so that ten or more can be combined per control operation to interpret flow visualization data, point sensor data, and model calculations. The pattern sensitivity of the nets will be utilized and tested to control wind tunnel operations at Mach 2.0 based on shock wave patterns.

Buggele, Alvin E.↗

NASA NTRS1995

Interpretation of IEEE-854 floating-point standard and definition in the HOL system

The ANSI/IEEE Standard 854-1987 for floating-point arithmetic is interpreted by converting the lexical descriptions in the standard into mathematical conditional descriptions organized in tables. The standard is represented in higher-order logic within the framework of the HOL (Higher Order Logic) system. The paper is divided in two parts with the first part the interpretation and the second part the description in HOL.

MULTIPLICATION SUBTRACTION↗

NASA NTRS1996

Compendium of Information for Interpreting the Microgravity Environment of the Orbiter Spacecraft

Science experiments are routinely conducted on the NASA shuttle orbiter vehicles. Primarily, these experiments are operated on such missions to take advantage of the microgravity (low-level acceleration) environment conditions during on-orbit operations. Supporting accelerometer instruments are operated with the experiments to measure the microgravity acceleration environment in which the science experiments were operated. Tne Principal Investigator Microgravity Services (PIMS) Project at NASA Lewis Research Center interprets these microgravity acceleration data and prepares mission summary reports to aid the principal investigators of the scientific experiments in understanding the microgravity environment. Much of the information about the orbiter vehicle and the microgravity environment remains the same for each mission. Rather than repeat that information in each mission summary report, reference information is presented in this report to assist users in understanding the microgravity-acceleration data. The characteristics of the microgravity acceleration environment are first presented. The methods of measurement and common instruments used on orbiter missions are described. The coordinate systems utilized in the orbiter and accelerometers are described. Some of the orbiter attitudes utilized in microgravity related missions are illustrated. Methods of data processing are described and illustrated. The interpretation of the microgravity acceleration data is included with an explanation of common disturbance sources. Instructions to access some of the acceleration data and a description of the orbiter thrusters are explained in the appendixes. A microgravity environment bibliography is also included.

DeLombard, Richard↗

NASA NTRS1994

Model for the Interpretation of Hyperspectral Remote-Sensing Reflectance

Remote-sensing reflectance is easier to interpret for the open ocean than for coastal regions because the optical signals are highly coupled to the phytoplankton (e.g., chlorophyll) concentrations. For estuarine or coastal waters, variable terrigenous colored dissolved organic matter (CDOM), suspended sediments, and bottom reflectance, all factors that do not covary with the pigment concentration, confound data interpretation. In this research, remote-sensing reflectance models are suggested for coastal waters, to which contributions that are due to bottom reflectance, CDOM fluorescence, and water Raman scattering are included. Through the use of two parameters to model the combination of the backscattering coefficient and the Q factor, excellent agreement was achieved between the measured and modeled remote-sensing reflectance for waters from the West Florida Shelf to the Mississippi River plume. These waters cover a range of chlorophyll of 0.2-40 mg/cu m and gelbstoff absorption at 440 nm from 0.02-0.4/m. Data with a spectral resolution of 10 nm or better, which is consistent with that provided by the airborne visible and infrared imaging spectrometer (AVIRIS) and spacecraft spectrometers, were used in the model evaluation.

Lee, Zhongping↗

NASA NTRS1999

Interpretation of Solar Wind Composition Measurements from Ulysses

Ion charge states measured in situ in interplanetary space carry information on the properties of the solar wind plasma in the inner corona. This information is, however, not easy to extract from the in situ observations. The goal of the proposal was to determine solar wind models and coronal observations that are necessary tools for the interpretation of charge state observations. It has been shown that the interpretation of the in situ ion fractions are heavily dependent on the assumptions about conditions in the inner corona.

Esser, Ruth↗

NASA NTRS1998

Absorption of Solar Radiation by the Cloudy Atmosphere: Further Interpretations of Collocated Aircraft Measurements

We have extended the interpretations made in two prior studies of the aircraft shortwave radiation measurements that were obtained as part of the Atmospheric Radiation Measurements (ARM) Enhanced Shortwave Experiments (ARESE). These extended interpretations use the 500 nm (10 nm bandwidth) measurements to minimize sampling errors in the broadband measurements. It is indicated that the clouds present during this experiment absorb more shortwave radiation than predicted by clear skies and thus by theoretical models, that at least some (less than or equal to 20%) of this enhanced cloud absorption occurs at wavelengths less than 680 nm, and that the observed cloud absorption does not appear to be an artifact of sampling errors nor of instrument calibration errors.

Cess, R. D.↗

NASA NTRS1999

Relativistic Electrons Observed at UARS and the Interpretation of their Storm-Associated Intensity Variations

The High Energy Particle Spectrometer (HEPS) instrument on the Upper Atmosphere Research Satellite (UARS) provides a database of electron intensities well resolved in energy and pitch-angle. Because of its 57 deg. orbital inclination, UARS encounters with magnetic shells L greater than 2 occur quite far off-equator (B/B (sub 0) greater than 9), corresponding to equatorial pitch angle alpha (sub 0) greater than 20 deg. Data acquired by HEPS (October 1991 through September 1994) span the declining phase of Solar Cycle 22. To reveal the storm-associated time dependence of relativistic electron intensities over the wide range of energies (50 keV to 5 MeV) covered by HEPS, we divide the daily average of the measured spectrum at a given L value (bin width = 0.25) by the corresponding 500-day average and plot the results with a color scale that spans only 2.5 decades. The data show that our off-equatorial electron intensities typically increase with time after the end of recovery phase (not during main phase or recovery phase) of each geomagnetic storm. The delay in off-equatorial energetic electron response and the subsequent lifetime of the corresponding electron flux enhancement seem to increase with particle energy above 300 keV. The trend below 300 keV seems to be opposite, such that the delay varies inversely with electron energy. Our working hypothesis for interpretation is that stormtime radial transport tends to increase the phase-space densities of trapped relativistic electrons but typically leads to a flux increases at specified energies only as the current (as indicated by Dst) decays. Flux enhancements in early recovery phase are greatest for equatorially mirroring electrons, and to pitch-angle anisotropies are initially large. Subsequent pitch-angle diffusion broadens the flux enhancement to particles that mirror off equator, thus gradually increasing low-altitude electron intensities (as detected by HEPS/UARS) on time scales equal to about 20% of corresponding lifetimes against diffusion into the loss cone. Alternative interpretations will also be examined.

Pesnell, W. D.↗