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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 685 records · Page 38

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NASA NTRS1979

Blocky craters - Implications about the lunar megaregolith

Radar, IR, and photogeologic properties of some 1310 lunar craters that have been catalogued as radar or IR anomalies, or both, are studied to determine whether a systematic difference in blocky craters exists between the lunar maria and terrae and whether this difference might be caused by a deep magaregolith of pulverized material forming the terra surface. Examination of Apollo orbital photography confirms that the radar and IR anomalies are correlated with blocky rubble around the craters, and analysis of the radar and IR data indicates systematic terra-mare differences. The data are interpreted by postulating that the maria are rock layers where craters eject boulder fields, that the terrae are covered by a relatively pulverized megaregolith at least 2 km deep, and that the terra craters eject less rocky rubble. It is concluded that blocky rubble, in the form of either actual rocks or partly consolidated blocks, contributes to the radar and IR signatures of the craters.

Thompson, T. W.↗

NASA NTRS1980

Red and nebulous objects in dark clouds - A survey

A search on the NGS-PO Sky Survey photographs has revealed 150 interesting nebulous and/or red objects, mostly lying in dark clouds and not previously catalogued. Spectral classifications are presented for 55 objects. These indicate a small number of new members of the class of Herbig-Haro objects, a significant number of new T Tauri stars, and a few emission-line hot stars. It is argued that hot, high-mass stars form preferentially in the dense cores of dark clouds. The possible symbiosis of high and low mass stars is considered. A new morphology class is defined for cometary nebulae, in which a star lies on the periphery of a nebulous ring.

Cohen, M.↗

NASA NTRS1980

Non-Io decametric radiation from Jupiter at frequencies above 30 MHz

Jovian Non-Io decametric radio events extending to frequencies of 30 MHz and above have been found in the Meudon-Nancay observations during 1978 and 1979, in the Voyager 1 PRA observations during February and March, 1979 and in the University of Colorado Radio Astronomy Observatory catalogue for 1960 to 1975. These events, which appear to be mostly associated with the Jovian A-source, query the existence of a cut-off, a little below 30 MHz, for the Non-Io emission and suggest the possibility of a single mechanism for both the Io and the Non-Io radiation.

Barrow, C. H.↗

NASA NTRS1981

Documentation for the machine-readable version of the thirteen color photometry of 1380 bright stars

The magnetic tape version of the catalogue of thirteen-color photometry of 1380 bright stars, containing data on the 13 color medium narrow band photometric system is described. Observations of essentially all stars brighter than fifth visual magnitude north of delta = -20 deg and brighter than fourth visual magnitude south of delta = -20 deg are included. It is intended to enable users to read and process the tape without the common difficulties and uncertainties.

Warren, W. H., Jr.↗

NASA NTRS1980

X-ray properties of quasars

The X-ray properties of 111 catalogued quasars have been examined with the imaging proportional counter on board the Einstein Observatory. Thirty-five of the objects, of redshift between 0.064 and 3.53, were detected as X-ray sources. The 0.5-4.5-keV X-ray properties of these quasars are correlated with their optical and radio continuum properties and with their redshifts and variability characteristics. The X-ray luminosity of quasars tends to be highest for those objects which are bright in the optical and radio regimes and which exhibit optically violent variability. These observations suggest that quasars should be divided into two classes on the basis of radio luminosities, spectra, evolution and underlying morphology and that quasars can make up a significant portion of the diffuse soft X-ray background only if the slope of the optical quasar log N-log S relation is steeper than 2 to m sub b of about 21.5.

Ku, W. H.-M.↗

NASA NTRS1981

The Sun among stars. IV - Albedos of Uranus and Neptune and the solar color

Geometric albedos in 48 adjacent 50 A bands from 3250 to 5600 A have been derived from observations of Uranus and Neptune. The solar analog found in earlier papers (Hardorp 1978, 1980) was chosen for these reductions, so these albedos are more reliable systematically than earlier ones and allow a choice among the scattering models of Savage et al. (1980). Green methane bands are stronger on Neptune. Strong solar absorption lines are found to be partially filled in by Raman-scattering. Neglect of this effect caused Croft et al. (1972) to find a solar color that is too blue. It probably also affected the classification of G-type stars in the Michigan Spectral Catalogue as well as Garrison's (1979) interpretation of IUE observations.

Hardorp, J.↗

NASA NTRS1981

Training site statistics from Landsat and Seasat satellite imagery registered to a common map base

Landsat and Seasat satellite imagery and training site boundary coordinates were registered to a common Universal Transverse Mercator map base in the Newport Beach area of Orange County, California. The purpose was to establish a spatially-registered, multi-sensor data base which would test the use of Seasat synthetic aperture radar imagery to improve spectral separability of channels used for land use classification of an urban area. Digital image processing techniques originally developed for the digital mosaics of the California Desert and the State of Arizona were adapted to spatially register multispectral and radar data. Techniques included control point selection from imagery and USGS topographic quadrangle maps, control point cataloguing with the Image Based Information System, and spatial and spectral rectifications of the imagery. The radar imagery was pre-processed to reduce its tendency toward uniform data distributions, so that training site statistics for selected Landsat and pre-processed Seasat imagery indicated good spectral separation between channels.

Clark, J.↗

NASA NTRS1981

Existing cometary data and future needs

To assist scientists studying comets and their interaction with the interplanetary medium, compilations of existing cometary observations and data plans for additional publication are reported. The works cited include updates and/or supplements to: (1) the Catalogue of Cometary Orbits, (2) Physical Characteristics of Comets, (3) the Atlas of Representative Cometary Spectra, (4) the Atlas Cometas-Viento Solar, (5) the Isophotometrischer Atlas der Kometen, and (6) the Atlas of Cometary Forms. An Atlas of Cometary Spectra and an Atlas of Comet Halley 1910 (II) photographs and spectra are in preparation.

Rahe, J.↗

NASA NTRS1981

Office of Space Terrestrial Applications (OSTA)/Applications Data Service (ADS) data systems standards

Standards needed to interconnect applications data service pilots for data sharing were identified. Current pilot methodologies are assessed. Recommendations for future work are made. A preliminary set of requirements for guidelines and standards for catalogues, directories, and dictionaries was identified. The user was considered to be a scientist at a terminal. Existing and emerging national and international telecommunication standards were adopted where possible in view of new and unproven standards.

Walton, B. A.↗

NASA NTRS1979

Spectral transformation in the SOFI complex for processing photographic images on the ES computer, part 1

A description is given of three programs catalogued in the form of object modules in the library of a system for processing photographic images computer. PFT is the subprogram of the multi-dimensional BPF of real-valued information, in the operative computer memory. INRECO is a subprogram-interface between the real and complex formats for representing two-dimensional spectra and images. FFT2 is a subprogram for calculating the correlation functions of the image using the previous subprograms.

Debabov, A. S.↗

NASA NTRS1982

Bibliographical index of objects observed by IUE

Six astronomical journals were searched and 343 papers describing studies using data obtained with the International Ultraviolet Explorer satellite were identified. From a review of these papers, the names of the astronomical objects discussed were recorded and compiled into a list of 2460 entries, along with each reference, and sorted by object name or catalogue number. This index enables a user to tell immediately where to find published papers describing IUE observation of the objects of interest to him.

Mead, J. M.↗

NASA NTRS1981

Preliminary results of the Air Force infrared sky survey

The paper presents a review of the Air Force Infrared Sky Survey with a discussion of the current status of the survey and an account of efforts to verify results contained in the AFCRL and AFGL catalogs. An overview of the AFGL catalog and subsets is given; 71% of the sources listed in the AFGL catalog are identified with sources in the Two Micron Sky Survey. Combining the data in the AFGL and TMSS catalogs yields information on the energy distributions of the brighter IR sources over four octaves. Attention is then given to studies of particular classes of objects found in the AFGL catalog, concentrating on objects not identified with stars in the TMSS or the Catalogue of Bright Stars. Finally, a summary is given of the relative populations of various classes of infrared sources found in the AFGL catalog, including a discussion of its extragalactic content.

Kleinmann, S. G.↗

NASA NTRS1983

A summary and integration of research concerning single pilot IFR operational problems

A review of seven research studies pertaining to Single Pilot IFR (SPIFR) operations was performed. Two studies were based on questionnaire surveys; two based on National Transportation Safety Board (NTSB) reports; two were based on Aviation Safety Reporting System (ASRS) incident reports, and one report used event analysis and statistics to forecast problems. The results obtained in each study were extracted and integrated. Results were synthesized and key issues pertaining to SPIFR operations problems were identified. The research that was recommended by the studies and that addressed the key issues is catalogued for each key issue.

Chapman, G. C.↗

NASA NTRS1981

Infrared astronomy - Scientific/military thrusts and instrumentation; Proceedings of the Meeting, Washington, DC, April 21, 22, 1981

A series of papers on infrared astronomy is presented. Among the topics discussed are those concerning programs, such as NASA's planning, the Cosmic Background Explorer and a cryogenic infrared radiance instrument for the Space Shuttle. Articles on infrared astronomy technology include those on an infrared camera for 10-micron astronomy, bulk and integrated acousto-optic spectrometers for molecular astronomy with heterodyne spectrometers, and airborne measurements of infrared atmospheric radiance and sky noise. Several papers on infrared astronomy spectroscopy are included, such as infrared heterodyne spectroscopy and infrared lines from shocked galactic gases. Among the articles on infrared astronomy catalogues and operations are discussions of groundbased infrared measurements using the AMOS/MOTIF facility and the prediction of infrared celestial source counts.

Boggess, N. W.↗

NASA NTRS1983

Alha 81005 meteorite - Chemical evidence for lunar highland origin

During the 1981-82 expedition to Antarctica a one-ounce meteorite was found on the slopes of the Allan Hills Mountain. This meteorite, which was catalogued as ALHA 81005, had unusual characteristics and resembled the lunar highland rocks. In a preliminary study, it was found that the chemical composition of the bulk sample of the meteorite matched closely with the Apollo 15 15418 highland rock which Laul and Schmitt (1973) analyzed by instrumental neutron activation analysis (INAA). The chemical data obtained for the clast, matrix, and bulk material of the ALHA 81005 meteorite are listed in a table together with corresponding data for the Apollo 15 15418 highland rock and the Luna 16 21013 highland rock. The close agreement of the data for the meteorite and the two lunar rocks suggests strongly that the ALHA 81005 is of lunar highland origin.

Laul, J. C.↗

NASA NTRS1984

5-GHz observations of cores in extended radio galaxies

Results are presented from a search for radio cores at 5 GHz with the VLA in 18 moderately luminous radio galaxies from the second Bologna catalogue. Maps of several of the ten detected cores indicate structure on arcsecond scales in addition to the unresolved central source. Higher-resolution, multifrequency observations are very desirable in future studies of such cores. A statistical study of these and previously observed samples of radio galaxies was then performed. It was found that the radio core luminosity is much stronger in galaxies that are optically bright than faint, and that strong cores tend to occur only in galaxies with luminous extended sources while weak cores can occur in all ranges of extended source luminosity.

Ulrich, M.-H.↗

NASA NTRS1984

Operating systems

A counter operating system creates a hierarchy of levels of abstraction, so that at a given level all details concerning lower levels can be ignored. This hierarchical structure separates functions according to their complexity, characteristic time scale, and level of abstraction. The lowest levels include the system's hardware; concepts associated explicitly with the coordination of multiple tasks appear at intermediate levels, which conduct 'primitive processes'. Software semaphore is the mechanism controlling primitive processes that must be synchronized. At higher levels lie, in rising order, the access to the secondary storage devices of a particular machine, a 'virtual memory' scheme for managing the main and secondary memories, communication between processes by way of a mechanism called a 'pipe', access to external input and output devices, and a hierarchy of directories cataloguing the hardware and software objects to which access must be controlled.

Denning, P. J.↗

NASA NTRS1984

Investigation of Toughened Neat Resins and Their Relations to Advanced Composite Mechanical Properties

Four epoxies (Hercules 3502, Hercules 2220-1 and 2220-3, and Ciba-Geigy Fibredux 914 epoxy) were evaluated to judge their merits within the ACEE program and also to provide material property input for a micromechanics finite element program. A casting procedure was developed for the four matrix systems mentioned and mechanical properties were studied at three test temperatures and two moisture contents. A scanning electron microscope study was performed to catalogue fracture surfaces for the unreinforced (neat) epoxies. In addition, tension testing, shear testing, a limited amount of fracture toughness testing, and thermal expansion coefficient and moisture expansion coefficient testing were carried out. Mechanical material properties were generated for input into a micromechanics program and to characterize these four matrix systems.

R. S. Zimmerman↗