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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 667 records · Page 37
All sourcesNASA NTRSDOE OSTI
NASA NTRS1987

Land cover change detection using a GIS-guided, feature-based classification of Landsat thematic mapper data

Landsat TM data were combined with land cover and planimetric data layers contained in the State of Michigan's geographic information system (GIS) to identify changes in forestlands, specifically new oil/gas wells. A GIS-guided feature-based classification method was developed. The regions extracted by the best image band/operator combination were studied using a set of rules based on the characteristics of the GIS oil/gas pads.

Enslin, William R.↗
NASA NTRS1988

Correlation mass method for analysis of neutrinos from supernova 1987A

Application of a time-energy correlation method to the Kamiokande II (KII) observations of neutrinos apparently emitted from supernova 1987A has yielded a neutrino rest mass of 3.6 eV. A Monte Carlo analysis shows a reconfirming probabilty distribution for the neutrino rest mass peaked at 2.8, and dropping to 50 percent of the peak at 1.4 and 4.8 eV. Although the KII data indicate a very short time scale of emission, over an extended period on the order of 10 sec, both data from the Irvine-Michigan-Brookhaven experiment and the KII data show a tendency for the more energetic neutrinos to be emitted earlier at the source, suggesting the possibility of cooling.

Chiu, Hong-Yee↗
NASA NTRS1987

Use of remote sensing for land use policy formulation

The overall objectives and strategies of the Center for Remote Sensing remain to provide a center for excellence for multidisciplinary scientific expertise to address land-related global habitability and earth observing systems scientific issues. Specific research projects that were underway during the final contract period include: digital classification of coniferous forest types in Michigan's northern lower peninsula; a physiographic ecosystem approach to remote classification and mapping; land surface change detection and inventory; analysis of radiant temperature data; and development of methodologies to assess possible impacts of man's changes of land surface on meteorological parameters. Significant progress in each of the five project areas has occurred. Summaries on each of the projects are provided.

Source record↗
NASA NTRS1988

Axions and SN1987A

The effect of free-streaming axion emission on numerical models for the cooling of the newly born neutron star associated with SN1987A is considered. It is found that for an axion mass of greater than approximately 10 to the -3 eV, axion emission shortens the duration of the expected neutrino burst so significantly that it would be inconsistent with the neutrino observations made by the Kamiokande II and Irvine-Michigan-Brookhaven detectors. However, the possibility has not been investigated that axion trapping (which should occur for masses greater than or equal to 0.02 eV) sufficiently reduces axion emission so that axion masses greater than approximately 2 eV would be consistent with the neutrino observations.

Burrows, Adam↗
NASA NTRS1988

CAMELOT 2

The design parameters of a space vehicle resulting from studies conducted at the University of Michigan are presented. The vehicle is identified as a Circulating Autonomous Mars-Earth Luxury Orbital Transport (CAMELOT). This report documents the results of the current study based on several key changes in the spacecraft systems and layout. Subjects discussed are propulsion, docking, power systems, habitat design, and orbital assembly.

Source record↗
NASA NTRS1989

Classification of earth terrain using polarimetric synthetic aperture radar images

Supervised and unsupervised classification techniques are developed and used to classify the earth terrain components from SAR polarimetric images of San Francisco Bay and Traverse City, Michigan. The supervised techniques include the Bayes classifiers, normalized polarimetric classification, and simple feature classification using discriminates such as the absolute and normalized magnitude response of individual receiver channel returns and the phase difference between receiver channels. An algorithm is developed as an unsupervised technique which classifies terrain elements based on the relationship between the orientation angle and the handedness of the transmitting and receiving polariation states. It is found that supervised classification produces the best results when accurate classifier training data are used, while unsupervised classification may be applied when training data are not available.

Lim, H. H.↗
NASA NTRS1989

US Activity with the OLYMPUS satellite

Future communication systems will move toward the 20 to 30 GHz frequency range for wider bandwidth and reduced interference, and will use small earth terminals. The ESA satellite OLYMPUS is scheduled for launch this June and will be ready for use in October. OLYMPUS has 12, 20, and 30 GHz beacons. Virginia Tech and Michigan Tech are working with NASA/JPL on an OLYMPUS experiment and hardware development program. OLYMPUS beacons provide coverage of the east coast of the US sufficient for attenuation measurements. The planned hardware for the OLYMPUS experiments is illustrated. The components of the experiment are summarized. A block diagram level overview of a typical channel is given and one of the four RF front ends is shown.

Stutzman, Warren L.↗
NASA NTRS1990

Axions and SN 1987A: Axion trapping

If an axion of mass between about 10(exp -3) eV and 1 eV exists, axion emission would have significantly affected the cooling of the nascent neutron star associated with SN 1987A. For an axion of mass less than about 10(exp -2) eV, axions produced deep inside the neutron star simply stream out; in a previous paper this case has been addressed. Remarkably, for an axion of mass greater than about 10(exp -2) eV axions would, like neutrinos, have a mean-free path that is smaller than the size of a neutron star, and thus would become 'trapped' and radiated from an axion sphere. In this paper the trapping regime is treated by using numerical models of the initial cooling of a hot neutron star that incorporate a leakage approximation scheme for axion-energy transport. The axion opacity is computed due to inverse nucleon-nucleon, axion bremsstrahlung, and numerical models are used to calculate the integrated axion luminosity, the temperature of the axion sphere, and the effect of axion emission on the neutrino bursts detected by the Kamiokande 2 (K2) and Irvine-Michigan-Brookhaven (IMB) water-Cherenkov detectors. The larger the axion mass, the stronger the trapping and the smaller the axion luminosity. The earlier estimate is confirmed and refined of the axion mass above which trapping is so strong that axion emission does not significantly affect the neutrino burst. Based upon the neutrino-burst duration--the most sensitive barometer of axion cooling--it is concluded that for an axion mass of greater than about 0.3 eV, axion emission would not have had a significant effect on the neutrino bursts detected by K2 and IMB. The present work, together with the previous work, strongly suggests that an axion with mass in the interval 10(exp -3) eV to 0.3 eV is excluded by SN 1987A.

Burrows, Adam↗
NASA NTRS1989

Conceptual design study for Infrared Limb Experiment (IRLE)

The phase A engineering design study for the Infrared Limb Experiment (IRLE) instrument, the infrared portion of the Mesosphere-Lower Thermosphere Explorer (MELTER) satellite payload is given. The IRLE instrument is a satellite instrument, based on the heritage of the Limb Infrared Monitor of the Stratosphere (LIMS) program, that will make global measurements of O3, CO2, NO, NO2, H2O, and OH from earth limb emissions. These measurements will be used to provide improved understanding of the photochemistry, radiation, dynamics, energetics, and transport phenomena in the lower thermosphere, mesosphere, and stratosphere. The IRLE instrument is the infrared portion of the MELTER satellite payload. MELTER is being proposed to NASA Goddard by a consortium consisting of the University of Michigan, University of Colorado and NASA Langley. It is proposed that the Space Dynamics Laboratory at Utah State University (SDL/USU) build the IRLE instrument for NASA Langley. MELTER is scheduled for launch in November 1994 into a sun-synchronous, 650-km circular orbit with an inclination angle of 97.8 deg and an ascending node at 3:00 p.m. local time.

Baker, Doran J.↗
NASA NTRS1990

A comparative study of infrared radiance measurements by an ER-2 based radiometer and the LANDSAT 5 Thematic Mapper (TM-6)

Infrared radiance measurements were acquired from a radiometer on the NASA ER-2 during a coincident LANDSAT 5 overpass on 28 Oct. 1986 as part of the FIRE Cirrus IFO in the vicinity of Lake Michigan. A comparative study is made to infer microphysical properties of the cirrus cloud field. Radiances are derived from the image by convolving the ER-2 radiometer's effective field of view along the flight path. A multistream radiative transfer model is used to account for the differences in spectral bandwidths, 10.40 to 12.50 microns for the LANDSAT band and 9.90 to 10.87 microns for the radiometer.

Hammer, Philip D.↗
NASA NTRS1990

Assessment of vegetation change in a fire-altered forest landscape

This research focused on determining the degree to which differences in burn severity relate to postfire vegetative cover within a Michigan pine forest. Landsat MSS data from June 1973 and TM data from October 1982 were classified using an unsupervised approach to create prefire and postfire cover maps of the study area. Using a raster-based geographic information system (GIS), the maps were compared, and a map of vegetation change was created. An IR/red band ratio from a June 1980 Landsat scene was classified to create a map of three degres of burn severity, which was then compared with the vegetation change map using a GIS. Classification comparisons of pine and deciduous forest classes (1973 to 1982) revealed that the most change in vegetation occurred in areas subjected to the most intense burn. Two classes of regenerating forest comprised the majority of the change, while the remaining change was associated with shrub vegetation or another forest class.

Jakubauskas, Mark E.↗
NASA NTRS1990

Olympus receiver evaluation and phase noise measurements

A set of measurements performed by the Michigan Tech Sensing and Signal Processing Group on the analog receiver built by the Virginia Polytechnic Institute (VPI) and the Jet Propulsion Laboratory (JPL) for propagation measurements using the Olympus Satellite is described. Measurements of local oscillator (LO) phase noise were performed for all of the LOs supplied by JPL. In order to obtain the most useful set of measurements, LO phase noise measurements were made using the complete VPI receiver front end. This set of measurements demonstrates the performance of the receiver from the Radio Frequency (RF) input through the high Intermediate Frequency (IF) output. Three different measurements were made: LO phase noise with DC on the voltage controlled crystal oscillator (VCXO) port; LO phase noise with the 11.381 GHz LO locked to the reference signal generator; and a reference measurement with the JPL LOs out of the system.

Campbell, Richard L.↗
NASA NTRS1990

Axions and SN 1987A: Axion trapping

If an axion of mass between about 10(exp -3) and 10 eV exists, axion emission would have significantly affected the cooling of the nascent neutron star associated with SN 1987A. For an axion of mass greater than about 10(exp -2) eV axions would, like neutrinos, have a mean-free path that is smaller than the size of a neutron star, and thus would become trapped and radiated from an axion sphere. The trapping regime is treated by using numerical models of the initial cooling of a hot neutron star that incorporate a diffusion approximation for axion-energy transport. The axion opacity due to inverse nucleon-nucleon, axion bremsstrahlung is computed; and then the numerical models are used to calculate the integrated axion luminosity, the temperature of the axion sphere, and the effect of axion emission on the neutrino bursts detected by the Kamiokande II (KII) and Irvine-Michigan-Brookhaven (IMB) water-Cherenkov detectors. The larger the axion mass, the stronger the trapping and the smaller the axion luminosity. The estimate of the axion mass is confirmed above which trapping is so strong that axion emission does not significantly affect the neutrino burst. Based upon the neutrino-burst duration - the most sensitive barometer of axion cooling - it is concluded that for an axion mass greater than about 3 eV axion emission would not have had a significant effect on the neutrino bursts detected by KII and IMB. It is strongly suggested that an axion with mass in the interval 10(exp -3) to 3 eV is excluded by the observation of neutrinos from SN 1987A.

Burrows, Adam↗
NASA NTRS1990

Multiband radar characterization of forest biomes

The utility of airborne and orbital SAR in classification, assessment, and monitoring of forest biomes is investigated through analysis of orbital synthetic aperature radar (SAR) and multifrequency and multipolarized airborne SAR imagery relying on image tone and texture. Preliminary airborne SAR experiments and truck-mounted scatterometer observations demonstrated that the three dimensional structural complexity of a forest, and the various scales of temporal dynamics in the microwave dielectric properties of both trees and the underlying substrate would severely limit empirical or semi-empirical approaches. As a consequence, it became necessary to develop a more profound understanding of the electromagnetic properties of a forest scene and their temporal dynamics through controlled experimentation coupled with theoretical development and verification. The concatenation of various models into a physically-based composite model treating the entire forest scene became the major objective of the study as this is the key to development of a series of robust retrieval algorithms for forest biophysical properties. In order to verify the performance of the component elements of the composite model, a series of controlled laboratory and field experiments were undertaken to: (1) develop techniques to measure the microwave dielectric properties of vegetation; (2) relate the microwave dielectric properties of vegetation to more readily measured characteristics such as density and moisture content; (3) calculate the radar cross-section of leaves, and cylinders; (4) improve backscatter models for rough surfaces; and (5) relate attenuation and phase delays during propagation through canopies to canopy properties. These modeling efforts, as validated by the measurements, were incorporated within a larger model known as the Michigan Microwave Canopy Scattering (MIMICS) Model.

Dobson, M. Craig↗
NASA NTRS1991

Utilization of lunar ilmenite: Basalt or regolith?

A critical discussion of whether lunar basalt or regolith should be used as a resource for mineral processing schemes on the lunar surface, with pros and cons for each argument is presented. A literature review has shown that the majority of authors feel that mining the lunar basalt, crushing it, and then processing to remove the desired minerals, would be the route to take. The argument that this method would not be a sound mineral processing practice is presented. Mining and crushing are difficult propositions even on Earth; to attempt such processes in the hostile lunar environment would be a phenomenal task. It would be better to start with a simpler scheme, such as processing the regolith, which can be adapted to the multitude of unknowns facing the first lunar production plant. If, however, the lunar mining trend is followed, it must be kept in mind that mining and processing technology which is radically different from what is currently available and used on Earth will have to be developed. Podnieks and Roepke (1987) and Lindroth and Podnieks (1987) have summarized the new technology that may be applicable, but this technology is very similar to the current, 99 percent inefficient technology used on Earth. One such possible technique is sodium vapor fragmentation of basalt. Initial testwork was conducted at Michigan Technological University on terrestrial basalt with extremely promising results, though much time and effort will be needed to fully develop this process.

Kawatra, S. K.↗
NASA NTRS1991

PG0027 + 260 - An example of a class of cataclysmic binaries with mysterious, but consistent, behavior

This paper reports extensive optical observations on the PG0027 + 260 binary, carried out on August 1984 with the 1.3 McGraw-Hill telescope and Mark II spectrometer at Michigan-Dartmouth-MIT Observatory on Kitt Peak. It is shown that this object is an eclipsing novalike variable with an orbital period of 3.51 hr. The PG0027 + 260 displays several unexplained phenomena which are remarkably similar to those of the SW Sex, DW UMa, and V1315 Aql, which are eclipsing novalike stars with periods between 3 and 4 hrs. The eclipse of the PG0027 + 260 is modeled, and it is shown that, while the mean eclipse light curve is easy to match, there is no simple explanation for the variable depth.

Thorstensen, John R.↗
NASA NTRS1991

The 27-28 October 1986 FIRE Cirrus case study - Retrieval of cloud particle sizes and optical depths from comparative analyses of aircraft and satellite-based infrared measurements

Infrared radiance measurements were acquired from a narrow-field nadir-viewing radiometer based on the NASA ER-2 aircraft during a coincident Landsat 5 overpass on October 28, 1986 as part of the FIRE Cirrus IFO in the vicinity of Lake Michigan. The spectral bandpasses are 9.90-10.87 microns for the ER-2-based radiometer and 10.40-12.50 microns for the Landsat thematic mapper band. After adjusting for spatial and temporal differences, a comparative study using data from these two instruments is undertaken in order to retrieve cirrus cloud ice-crystal sizes and optical depths. Retrieval is achieved by analysis of measurement correlations between the two spectral bands and comparison to multistream radiative transfer model calculations. The results indicate that the equivalent sphere radii of the cirrus ice crystals were typically less than 30 microns. Such particles were too small to be measured by the available in situ instrumentation. Cloud optical depths at a reference wavelength of 11.4 microns ranged from 0.3 to 2.0 for this case study. Supplemental results in support of this study are described using radiation measurements from the King Air aircraft, which was also in near coincidence with the Landsat overpass.

Hammer, Philip D.↗
NASA NTRS1990

Studies in general aviation aerodynamics

The Department of Aerospace Engineering at the University of Maryland has completed a research study for NASA Langley on the application of drooped leading edges to high aspect wings. The experimental study conducted for this grant was a natural extension of work previously conducted at NASA Ames, the University of Michigan, NASA Langley and the University of Maryland. Previous research had shown that wing planform modifications (commonly referred to as drooped leading edge mods) could have a significant effect on reducing or eliminating the stall/spin characteristics of General Aviation (GA) aircraft. All aircraft studied in the earlier work had relatively low aspect ratio wings (AR = 6). Since future GA aircraft will feature higher aspect ratio wings, the obvious question was: how well will the dropped leading edge work on higher aspect ratio wings? The focus of the current study was to examine the effectiveness of the drooped leading edge modifications to higher aspect ratio wings with AR = 9 to 12.

Winkelmann, Allen E.↗