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At least 235 records · Page 13

Hydrogen fueled subsonic aircraft - A prospective

The performance characteristics of hydrogen-fueled subsonic transport aircraft are compared with those of aircraft using conventional aviation kerosene. Results of the Cryogenically Fueled Aircraft Technology Program sponsored by NASA indicate that liquid hydrogen may be particularly efficient for subsonic transport craft when ranges of 4000 km or more are involved; however, development of advanced cryogenic tanks for liquid hydrogen fuel is required. The NASA-sponsored program also found no major technical obstacles for international airports converting the liquid hydrogen fueling systems. Resource utilization efficiency and fuel production costs for hydrogen produced by coal gasification or for liquid methane or synthetic aviation kerosene are also assessed.

Witcofski, R. D.↗

Asteroid surface compositions from infrared spectroscopic observations - Results and prospects

Advances in IR detector technology, the increased availability of large aperture telescopes, and the techniques of Fourier transform spectroscopy now permit IR (with wavelengths greater than 1 micron) spectroscopic observations of asteroid surfaces. Asteroids already observed include Ceres, Vesta, and Eros. These initial results demonstrate that such studies can contribute new data concerning asteroid compositions. Some of the most diagnostic features of mineral spectra are in the IR spectral region, and for featureless spectra characterized only by slopes the extension of the spectral reflectivity curve into the IR provides tighter constraints on possible mineralogies. A systematic study of additional asteroids should exploit even further this new observational link to problems of meteorite origin and solar system evolution.

Larson, H. P.↗

Prospects for detection of gravitational radiation by simultaneous Doppler tracking of several spacecraft

This paper reports a calculation of the effect of gravitational radiation on the observed Doppler shift of a sinusoidal electromagnetic signal transmitted to, and coherently transponded from, distant spacecraft. It is found that the effect of plane gravitational waves on such observations is not intuitively immediate, and in fact depends sensitively on the spacecraft direction, which suggests the possibility of detecting such plane waves by simultaneous Doppler tracking of several spacecraft. The need for broad band gravitational wave observations, the required stabilities of time keeping standards, and astrophysical sources expected in the Very Low Frequency band are briefly discussed.

Estabrook, F. B.↗

Future prospects for spectroscopic and direct work - Optical and UV

A description of the main features and proposed instrumentation of the 2.4 m Space Telescope is given. Highlights of work that can be planned on active nuclei of galaxies, QSOs, and BL Lac objects are briefly outlined, involving spectroscopy over wavelengths from 1200 A to 1 mm, direct imaging with 0.1 sec resolution, and the capability for 0.1 sec resolution along the spectrograph slit. The resolution, the much reduced sky background, and the full wavelength coverage also make possible important observations relevant to cosmology.

Burbidge, E. M.↗

The ionosphere and airglow of Venus - Prospects for Pioneer Venus

The paper presents model calculations for the Cytherean nighttime and daytime ionosphere. It is shown how some of the proposed mechanisms can be tested with the aid of the Pioneer Venus observations scheduled for December 1978. Theoretical calculations of the energetics of the Cytherean ionosphere are performed, and it is concluded that the Project Venus measurements will find elevated ion and electron temperatures, resulting primarily from energy fluxes associated in some manner with the solar wind. According to this model, the energy flux will act directly on the ion gas. Ultraviolet dayglow intensities were calculated, and it is anticipated that hundreds of kR's of CO2-related emission features such as the CO Cameron bands will be observed. Nightside ionosphere calculations were made assuming the precipitation of energetic electrons as an ionization source, and the intensities of some of the resulting emission features are calculated.

Cravens, T. E.↗

Remote sensing applied to prospecting of thermomineral water in the county of Caldas Novas-Goias

LANDSAT imagery of the region were studied allowing the placement of the area of study in the regional geological context. A geological mapping of the 1.60.000 scale was done. A methodology was developed which consisted in a regional temperature mapping using trend surface analysis. Through the correlation of all these data, four different areas were localized with a high potential as thermomineral sources.

Veneziani, P.↗

Prospects of a mathematical theory of human behavior in complex man-machine systems tasks

A hierarchy of human activities is derived by analyzing automobile driving in general terms. A structural description leads to a block diagram and a time-sharing computer analogy. The range of applicability of existing mathematical models is considered with respect to the hierarchy of human activities in actual complex tasks. Other mathematical tools so far not often applied to man machine systems are also discussed. The mathematical descriptions at least briefly considered here include utility, estimation, control, queueing, and fuzzy set theory as well as artificial intelligence techniques. Some thoughts are given as to how these methods might be integrated and how further work might be pursued.

Johannsen, G.↗

Status and prospects of computational fluid dynamics

The use and limitations on using computational aerodynamics in approximating inviscid linear, inviscid nonlinear, vicous time averaged, and viscous time dependent flow past airfoils, wings, and aircraft is reviewed. The current status of two- and three-dimensional time averaged Navier-Stokes equation is discussed and possible applications for the 1980 and 1985 to 1990 period is projected for three-dimensional applications.

Chapman, D. R.↗

Present status and future prospects for NASA's program in geodynamics

An overview of NASA's involvement in developing systems for precise determination of polar motion, earth rotation, and position on the earth's surface is given. The observational methods discussed are laser ranging to the moon and to artificial satellites, and very long baseline microwave interferometry. A plan for a geodynamics program to apply space technology to research in earth dynamics is outlined.

Flinn, E. A.↗

Electric energy demand and supply prospects for California

A recent history of electricity forecasting in California is given. Dealing with forecasts and regulatory uncertainty is discussed. Graphs are presented for: (1) Los Angeles Department of Water and Power and Pacific Gas and Electric present and projected reserve margins; (2) California electricity peak demand forecast; and (3) California electricity production.

Jones, H. G. M.↗

Prospects for coal slurry pipelines in California

The coal slurry pipeline segment of the transport industry is emerging in the United States. If accepted it will play a vital role in meeting America's urgent energy requirements without public subsidy, tax relief, or federal grants. It is proven technology, ideally suited for transport of an abundant energy resource over thousands of miles to energy short industrial centers and at more than competitive costs. Briefly discussed are the following: (1) history of pipelines; (2) California market potential; (3) slurry technology; (4) environmental benefits; (5) market competition; and (6) a proposed pipeline.

Lynch, J. F.↗

Radio observations of asteroids: Results and prospects

Radio observations of the asteroids can provide information on the thermal and dielectric properties of the surface materials and because the radio emission arises somewhat below the surface, the data give some indication of layering. Observational difficulty has limited the investigations to only 6 asteroids: 1 Ceres and 324 Bamberga appear to have a layer of dust covering a more compacted material; the data on 4 Vesta cannot be matched by any current models for the surface; and the results for 18 Melpomene, 31 Euphrosyne and 433 Eros are too incomplete for firm conclusions. Future possibilities include more accurate radiometry of a few selected asteroids of different taxonomic classes and actual resolution of some of the larger objects by aperture synthesis techniques.

Dickel, J. R.↗

Radio observations of asteroids: Results and prospects

Radio observations of the asteroids can provide information on the thermal and dielectric properties of the surface materials and because the radio emission arises somewhat below the surface, the data give some indication of layering. Observational difficulty limited the investigations to only 6 asteroids:1 Ceres and 324 Bamberga appear to have a layer of dust covering a more compacted material; the data on 4 Vesta cannot be matched by any current models for the surface; and the results for 18 Melpomene, 31 Euphrosyne and 433 Eros are too incomplete for firm conclusions. Future possibilities include more accurate radiometry of a few selected asteroids of different tuxonomic classes and actual resolution of some of the larger objects by aperture synthesis techniques.

Dickel, J. R.↗

The LANDSAT program: The present and prospects

The LANDSAT program is described and the benefits derived from it are pointed out. The successive LANDSAT launchings and its respective equipment are discussed. The earth's surface covering, the techniques of relaying the information to the ground, a description of the LANDSAT D system, a comparison between the multispectral scanner on LANDSAT C and the MSS on LANDSAT D, and information about the regions of the electromagnetic spectrum covered by LANDSAT C and LANDSAT D are discussed.

Whitman, R. I.↗

Alternate aircraft fuels prospects and operational implications

The paper discusses NASA studies of the potentials of coal-derived aviation fuels, specifically synthetic aviation kerosene, liquid methane, and liquid hydrogen. Topics include areas of fuel production, air terminal requirements for aircraft fueling (for liquid hydrogen only), and the performance characteristics of aircraft designed to utilize alternate fuels. Energy requirements associated with the production of each of the three selected fuels are determined, and fuel prices are estimated. Subsonic commercial air transports using liquid hydrogen fuel have been analyzed, and their performance and the performance of aircraft which use commercial aviation kerosene are compared. Environmental and safety issues are considered.

Witcofski, R. D.↗

Global atmospheric sampling program - Prospects for establishing a tropospheric ozone budget from commercial aircraft data

A preliminary analysis of zonally averaged, ozone concentration data obtained from commercial (GASP) aircraft between the equator and 60 deg North indicates that ozone in the upper troposphere exhibits a primary maximum during the spring, and, in middle latitudes, a secondary maximum in the summer of both 1975 and 1976. A late-fall/early-winter minimum also appears and seems consistent with previous upper air measurements. The April ozone maximum has been well documented and appears at the time when the stratospheric ozone content is greatest and cyclogenetic activity is most vigorous. However, the secondary maximum in June has not been widely observed or quoted as a unique feature. It is hypothesized that the rapid ascent of the tropopause between midspring and summer could account for the incorporation of ozone-rich, stratospheric air into the upper troposphere with a subsequent dilution during the following months. This may explain certain aspects of the annual ozone cycle in the lower troposphere which occasionally exhibit a bimodal distribution during the warm season.

Falconer, P. D.↗