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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 451 records · Page 25
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Image processing of galaxy photographs

New computer techniques for analyzing and processing photographic images of galaxies are presented, with interesting scientific findings gleaned from the processed photographic data. Discovery and enhancement of very faint and low-contrast nebulous features, improved resolution of near-limit detail in nebulous and stellar images, and relative colors of a group of nebulosities in the field are attained by the methods. Digital algorithms, nonlinear pattern-recognition filters, linear convolution filters, plate averaging and contrast enhancement techniques, and an atmospheric deconvolution technique are described. New detail is revealed in images of NGC 7331, Stephan's Quintet, Seyfert's Sextet, and the jet in M87, via processes of addition of plates, star removal, contrast enhancement, standard deviation filtering, and computer ratioing to bring out qualitative color differences.

Arp, H.↗
NASA NTRS1978

Meteorological limits on the growth and development of screwworm populations

A program to evaluate the use of remotely sensed data as an additional tool in existing and projected efforts to eradicate the screwworm began in 1973. Estimating weather conditions by use of remotely sensed data was part of the study. Next, the effect of weather on screwworm populations was modeled. A significant portion of the variation in screwworm population growth and development has been traced to weather-related parameters. This report deals with the salient points of the weather and the screwworm population interaction.

Phinney, D. E.↗
NASA NTRS1979

The ecological variations in thermal infrared emissivity of vegetation

The author has identified the following significant results. Through a series of contrasts, the statistical significance of differences in emissivity was determined for vegegation in dry and humid deserts, montane and deciduous rain forests, and the temperate region. No significant differences were found between the two types of desert vegetation or among the types of nondesert vegetation. However, the rain forest vegetation was significantly different from that of the temperate region. On a community-wide level, there is some physiological adaptation in plants to their radiational environment.

Arp, G. K.↗
NASA NTRS1979

Some properties of the knots in the M87 jet

Photographs taken in 1956 by Baade show the knots in the jet of M87 to be polarized. In 1978, these plates were repeated under conditions as identical as possible. A careful comparison indicates that the polarization and intensity of the knots have changed in the 22 year interval. Emission lines in the nucleus of M87 not previously seen have been revealed by extensive 5 m SIT spectroscopy. The same spectroscopy with galaxy subtracted, however, has failed to reveal any features in the jet. The known optical and radio properties of the jet are reviewed. A coincidence is found in almost all of the defining properties of BL Lacertae objects with the properties of the knots in the jet. Statistical studies of the distribution of BL Lacertae objects near bright galaxies reveals a marginally significant excess of such associations.

Sulentic, J. W.↗
NASA NTRS1982

The dryout region in frictionally heated sliding contacts

Some conditions under which boiling and two-phase flow can occur in or near a wet sliding contact are determined and illustrated. The experimental apparatus consisted of a tool pressed against an instrumented slider plate and motion picture sequences at 4000 frames/sec. The temperature and photographic data demonstrated surface conditions of boiling, drying, trapped gas evolution (solutions), and volatility of fluid mixture components. The theoretical modeling and analysis are in reasonable agreement with experimental data.

Hendricks, R. C.↗
NASA NTRS1982

The dryout region in frictionally heated sliding contacts

Some conditions under which boiling and two-phase flow can occur in or near a wet sliding contact are determined and illustrated. The experimental apparatus consisted of a tool pressed against an instrumented slider plate and motion picture sequences at 4000 frames/sec. The temperature and photographic data demonstated surface conditions of boiling, dry, trapped gas evolution (solutions), and volatility of fluid mixture components. The theoretical modeling and analysi are in reasonable agreement with experimental data. Previously announced in STAR as N82-28574

Hendricks, R. C.↗
NASA NTRS1983

Six quasars near the jets of NGC 1097

Six quasars have been discovered in a 0.43 sq deg field surrounding NGC 1097. The quasars are grouped in a small area of the field: five of the quasars lie within the area defined by the jets emanating from the galaxy. Four of the quasars are clearly detected in a deep X-ray map of the field. The probability of finding such an unusual configuration is discussed.

Wolstencroft, R. D.↗
NASA NTRS1983

The importance of geobotany in geological remote sensing applications

A description of the different effects of variations in ground cover vegetation on remote sensing data in geological and prospecting applications is presented. The different variations are divided into three categories: structural; taxonomic and spectral. Structural variations include changes in the physical appearance of ground cover which may be detectable by a remote sensing instrument. Taxonomic variations occur in those plant communities which are associated with specific geological regions. Spectral variations are due to specific geochemical stresses which may be useful in characterizing geological features at a site. The need for a general scheme for the interpretation of geobotanical remote sensing data is discussed: Geosat data for the field reflectance spectra of different tree species in West Virginia are presented as examples.

Mouat, D. A.↗
NASA NTRS1985

Transient Heat Transfer in Zero Gravity Environment

The objective is to provide computer codes and/or correlations for application in the design of transient heat transfer systems. The mathematical models in the computer codes are being tested by experimental data obtained in the laboratory using optical techniques. The elimination of natural convection (buoyancy) in the experimental data obtained in zero-g (KC-135) facilitates the study of thermal expansion effects which is of interest in the development and testing of the mathematical models of the transient heat transfer. Initial flight in the KC 135 (June 1983) suggested some modifications to the experimental apparatus and the data acquisition technique (high speed video will replace high speed movies for recording optical records generated during the experiments). A series of KC-135 flights with this experiment on board are scheduled for summer/fall 1984. The acquisition of the aforementioned data using interferometry and beam deflection optical techniques is anticipated. The measurements provide time dependent temperature fields above a horizontal heater surface submerged in a static fluid (Freon 13). The heater surface is electrically heated for a time interval approximately 0.100 sec. during which the data are optically recorded.

Giarratano, P. G.↗
NASA NTRS1985

The response of numerical weather prediction analysis systems to FGGE 2b data

An intercomparison of analyses of the main PGGE Level IIb data set is presented with three advanced analysis systems. The aims of the work are to estimate the extent and magnitude of the differences between the analyses, to identify the reasons for the differences, and finally to estimate the significance of the differences. Extratropical analyses only are considered. Objective evaluations of analysis quality, such as fit to observations, statistics of analysis differences, and mean fields are discussed. In addition, substantial emphasis is placed on subjective evaluation of a series of case studies that were selected to illustrate the importance of different aspects of the analysis procedures, such as quality control, data selection, resolution, dynamical balance, and the role of the assimilating forecast model. In some cases, the forecast models are used as selective amplifiers of analysis differences to assist in deciding which analysis was more nearly correct in the treatment of particular data.

Hollingsworth, A.↗
NASA NTRS1986

Volume-energy parameters for heat transfer to supercritical fluids

Reduced Nusselt numbers of supercritical fluids from different sources were grouped by several volume-energy parameters. A modified bulk expansion parameter was introduced based on a comparative analysis of data scatter. Heat transfer experiments on liquefied methane were conducted under near-critical conditions in order to confirm the usefulness of the parameters. It was experimentally revealed that heat transfer characteristics of near-critical methane are similar to those of hydrogen. It was shown that the modified bulk expansion parameter and the Gibbs-energy parameter grouped the heat transfer data of hydrogen, oxygen and methane including the present data on near-critical methane. It was also indicated that the effects of surface roughness on heat transfer were very important in grouping the data of high Reynolds numbers.

A. Kumakawa↗
NASA NTRS1987

Accuracy of atmospheric angular momentum estimates from operational analyses

An attempt is made to assess the accuracy of global atmospheric angular momentum determinations by comparing time series of this quantity derived from both the NMC and ECMWF zonal wind analyses for 1981-85. Over this period, the rms difference betwen the two atmospheric series is comparable to the difference between an atmospheric momentum series and the series that is consistent with observed (nontidal) changes in earth rotation. Most of the difference between the NMC and ECMWF global momentum values comes from the region between 33 deg S and 16 deg N. Differences between NMC and ECMWF regional momentum values become vanishingly small in the high latitudes of the Northern Hemisphere, but they remain large throughout the entire Southern Hemisphere. An annual signal of up to 0.5 m/s exists in the difference between the NMC and ECMWF tropospheric zonal wind fields. Although seemingly small, this signal is vertically coherent and leads to a marked annual component in the NMC-ECMWF difference momentum values in the tropics and also for the Northern Hemisphere as a whole.

Rosen, Richard D.↗
NASA NTRS1987

Transient heat transfer and thermophysical properties measurements in low gravity

Theoretical computer models and correlations which describe phenomena important in the design of transient heat transfer systems are verified and extended. Attention is given to heat transfer to a fluid near the thermodynamic critical point, i.e., a highly compressible fluid. The validity of the computer model is tested by conducting heat-transfer experiments in a low gravity environment where gravity-driven motion is essentially eliminated. It is noted that the NASA KC135 aircraft provides a useful low-g platform for experimental work and provides valuable experience and background for experiments ultimately designed to fly on the Space Shuttle.

Giarratano, P. J.↗
NASA NTRS1989

Concrete lunar base investigation

This paper presents results of structural analyses and a preliminary design of a precast, prestressed concrete lunar based subjected to one atmosphere internal pressure. The proposed infrastructure measures 120 ft in diameter and 72 ft in height, providing 33,000 sq ft of work area for scientific and industrial operations. Three loading conditions were considered in the design: (1) during construction; (2) under pressurization; and (3) during an air-leak scenario. A floating foundation, capable of rigid body rotation and translation as the lunar soil beneath it yields, was developed to support the infrastructure and to ensure the air-tightness of the system. Results reveal that it is feasible to use precast, prestressed concrete for construction of large lunar bases on the moon.

Lin, T. D.↗
NASA NTRS1989

Thermophysical properties of Helium-4 from 0.8 to 1500 K with pressures to 2000 MPa

Tabular summary data of the thermophysical properties of fluid helium are given for temperatures from 0.8 to 1500 K, with pressures to 2000 MPa between 75 and 300 K, or to 100 MPa outside of this temperature band. Properties include density, specific heats, enthalpy, entropy, internal energy, sound velocity, expansivity, compressibility, thermal conductivity, and viscosity. The data are calculated from a computer program which is available from the National Institute of Standards and Technology. The computer program is based on carefully fitted state equations for both normal and superfluid helium.

Arp, Vincent D.↗
NASA NTRS1990

The peculiar hydrogen cloud in the Virgo Cluster and 3C 273

It is shown that the nearest bright extragalactic object to the peculiar hydrogen cloud recently discovered in the Virgo Cluster by Giovanelli and Haynes is the bright QSO 3C 273. Further, it is pointed out that the jet in 3C 273 points in almost the same direction as the major axis of the cloud. Despite the redshift difference, possible physical connections between the cloud and 3C 273 are explored.

Arp, H. C.↗
NASA NTRS1990

The extragalactic universe - An alternative view

It is argued that the currently popular cosmological model is subject to many doubts based on observational data which suggest that there never was a Big Bang. It is further argued that the observational evidence concerning nonthermal objects with large redshifts leads to the conclusion that these redshifts are largely intrinsic in origin. These objects do not lie at large cosmological distances, but rather much closer with z(c) less than about 0.1. This in turn means that there is no evidence for evolution in the discrete objects, and that what is seen in them are creation events involving the ejection of new matter from the nuclei of galaxies.

Arp, H. C.↗