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The 50 horsepower solar powered irrigation facility near Gila Bend, Arizona which includes a Rankine cycle demonstrates the technical feasibility of solar powered pumping. The design of a facility specifically for the irrigation farmer using the technology that has been developed over the last four years is proposed.
There are no author-identified significant results in this report.
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Simultaneous observations by Helios 1 and Helios 2 over four solar rotations, between January 20 and May 23, 1976, were used to determine the latitudinal dependence of the polarity of the interplanetary magnetic field within plus or minus 7.23 deg of the solar equator and within 1 AU. The longitudinal and latitudinal positions of the sector boundary crossing are consistent with a warped sector boundary which extended from the sun to 1 AU and was inclined approximately 10 deg with respect to the heliographic equator. This is consistent with simultaneous Pioneer 11 observations, which showed unipolar fields at approximately 16 deg latitude at heliocentric distances greater than 3.5 AU. Two sectors were observed at southern latitudes; however, four sectors were observed at northern latitudes on two rotations, indicating a distortion from planarity of the sector boundary surface.
In Doppler positioning systems, the basic method of point positioning involves a stable transmitted satellite signal received by a ground based antenna and receiver. This received frequency is mixed with a locally generated reference frequency, resulting in a beat frequency. A Doppler equation has been developed which includes all known contributions to this Doppler count. Upon measuring this count at the receiver and by using the precise orbital position of the transmitting satellite, the position of a receiver antenna can be calculated. However, for geodetic accuracy, it is assumed that the receiver antenna is stationary and has a predictable constant phase reference point. Thus, if a phase variation does exist, it may be misinterpreted as an added Doppler shift due to range change.
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The role of local particle injections and accelerations in determining energetic particle spectra used as an indication of the radial diffusion of trapped magnetospheric particles is assessed. An idealized one-dimensional steady-state model of magnetospheric radial transport in which diffusion is balanced against particle sources and sinks is used to illustrate the effects of particle injection at a point and over a band of radii in which the observation point is immersed in particle spectra. For an injection spectrum uniformly distributed in space and a step function in energy, it is shown that the energy dependence of the measured spectrum is determined not only by adiabatic energization of the input spectrum but by the spatial structure of the injection and the radial dependence of the diffusion coefficient as well. The relevance of the results for observations of particle spectra in the terrestrial and Jovian magnetospheres is also considered
Shock associated noise from unheated supersonic jets is investigated through acoustic measurements in both the near and far fields. The peak Helmholtz number of broadband shock noise is found to be independent of nozzle pressure ratio when based on the length of the shock cells and the ambient speed of sound. This indicates that the acoustic wavelengths generated in the shock noise process are limited in size by the shock cell spacing. Excellent agreement between power spectral densities measured at various far-field angles is obtained at and above the peak shock noise frequency when source convection effects are included. Results show a directivity of broadband shock noise pointed in the upstream direction, with omnidirectionality being approached only at high pressure ratios. The relative importance of shock noise with respect to jet mixing noise is found to be maximum near the pressure ratio at which a Mach disc begins to form in the jet. Near-field measurements point to the downstream shock cells as the region where the dominant shock noise eminates from the jet.
An experimental investigation was conducted to determine the effect of wing vertical position and horizontal-tail vertical and axial position on the static aerodynamic characteristics of a wing-body-horizontal-tail configuration. The configurations investigated included the wing in a high, mid, or low position on the body with the horizontal tail in each of these vertical positions as well as in three axial positions. The closest position of the horizontal tail to the wing essentially provided an all-wing configuration. In addition, tests were made for the three wing positions with the horizontal tail removed. The tests were made in three different wind tunnels to provide data for a Mach number range from 0.25 to 4.63. The purpose of the investigation was to illustrate the strong effects of interference flow fields as a function of geometry and flight attitude and to provide a systematic data base that might be useful for correlation with various analytical techniques. The results indicate some arrangements that might lead to aerodynamic problems and others in which the interference flow fields might be favorably exploited. The results suggest that a coplanar concept with a translating horizontal tail could potentially minimize the aerodynamic changes with Mach number and provide more optimum performance over the Mach number range.
Imaging radar was evaluated as an adjunct to conventional petroleum exploration techniques, especially linear mapping. Linear features were mapped from several remote sensor data sources including stereo photography, enhanced LANDSAT imagery, SLAR radar imagery, enhanced SAR radar imagery, and SAR radar/LANDSAT combinations. Linear feature maps were compared with surface joint data, subsurface and geophysical data, and gas production in the Arkansas part of the Arkoma basin. The best LANDSAT enhanced product for linear detection was found to be a winter scene, band 7, uniform distribution stretch. Of the individual SAR data products, the VH (cross polarized) SAR radar mosaic provides for detection of most linears; however, none of the SAR enhancements is significantly better than the others. Radar/LANDSAT merges may provide better linear detection than a single sensor mapping mode, but because of operator variability, the results are inconclusive. Radar/LANDSAT combinations appear promising as an optimum linear mapping technique, if the advantages and disadvantages of each remote sensor are considered.
Although no significant results were achieved during the report period, research continues. A sample of imagery showing thermal inertia and temperature differences over the northeastern United States and Europe was received. The project coordinator attended a TELLUS Project meeting in Ispra, Italy at which general guidelines for the future were established and the quality of the data received was discussed.
The requirements of symmetry and convexity in the application of algorithms for the minimization or maximization of a function are discussed. It is argued that if a function of a single variable is convex and symmetric in a neighborhood of an extremum, the extremum may be approximated to the precision that increases by at least a power of two per functional evaluation. The procedure may be used to drive a complex optimization procedure in the multivariate area estimation problem encountered in remote sensing.
Solar wind plasma and magnetic field data and ionospheric data obtained from the Pioneer Venus orbiter are discussed. The variation in the magnetic field pressure within the magnetic barrier is shown to be similar to that expected for the solar wind pressure variations along an obstacle's boundary when a more realistic approximation of the shape of the ionosphere is included. Simultaneous solar wind pressure, ionospheric pressure, and magnetic barrier pressure data reveal that the ionospheric pressure below the ionopause is approximately equal to the solar wind pressure. The magnetic barrier pressure is found to be equal to approximately 2/3 to 3/4 of both the solar wind pressure and the ionospheric pressure. Estimates of the hot plasma pressure contribution to the total pressure in the magnetic barrier vary from 1/4 to 1/3. Just below the ionopause the ionospheric pressure deviations from the mean ionospheric pressure are significant, especially below approximately 400 km; they appear to be indicative of the adjustment of the ionospheric structure to changeing solar wind conditions. A first-order model of the ionopause pressure variations as a function of height and solar-zenith angle is proposed. Venera 9 and Venera 10 bow shock crossings are then analyzed for solar zenith angles in the range from approximately 25 deg to approximately 153 deg. A comparison of Venera 9 and Venera 10 bow shock crossings with those observed by the Pioneer Venus orbiter suggests that both the secular variation and the latitudinal asymmetry may be responsible for the closer shock crossings of the Venera 9 and Venera 10 spacecraft.
A gamma-ray burst was recorded on 1979 April 6 at 1140 UT by instruments on the Pioneer Venus Orbiter (PVO), Venera 11 (V11), Venera 12 (V12), Prognoz 7 (P7), and International Sun-Earth Explorer-3 (ISEE-3) spacecraft. The event consisted of a single spike of 0.2 s duration and had a spectral feature near 400 keV, thus resembling the 1979 March 5 event in two respects. However, important differences in rise time and spectral hardness make it impossible to conclude positively that the two events shared the same mechanism or had comparable energetics. Constraints placed by these findings on the energetics and types of objects that could be responsible for the April 6 and possibly the March 5 bursts are discussed.
Jupiter's reflectivity was measured as a function of wavelength between 3000 and 10,500 Angstrom for two nights during the 1979 apparition. The spectra obtained were used to calibrate the wavelength response of Voyager images and to establish differences from previous apparitions. The observations were taken in the prominent belts and zones and both polar caps along the central meridian using a slit of dimensions 2.33 x 2.5 sq arcsec. The equivalent widths of the 6190 and 7270 Angstrom CH4 bands were measured; compared to the 1976 apparition, there was significantly less CH4 absorption in the north tropical zone. Such equivalent-width decreases are said to result from either a reduction in particle albedo or a decrease in the scattering mean free path owing to a greater concentration of aerosol particles in the NTrZ.
While observational and theoretical investigations have clearly indicated that the shape of the magnetosphere is very nearly symmetric about the plane determined by the aberrated solar wind flow direction and the earth's magnetic dipole, many processes such as magnetic pulsations and geomagnetic activity which should be shape dependent do not exhibit symmetry about this plane. The present paper proposes a solution to this apparent paradox in terms of the shifting of the stagnation point in the magnetosheath flow. It is shown that the interplanetary magnetic field can act to shift the stagnation point on the order of 15 deg from the nose towards dawn during periods of low Alfven Mach number without an appreciable aberration of the magnetopause, accounting for the observations of pulsation demarcation and magnetic reconnection.
The filter produces the maximum likelihood estimates for average values of the spacecraft position and attitude errors during a single scene. The quality of the filter performance is characterized by the maximal cross and along track residual errors for which probability distributions can be calculated analytically for a given pattern of control points. The filter with an automatic selection of the best set of estimates provides geodetic correction at 90% of pixels with residual errors less than 40 m for four or more control points and the mean squared measurement errors of the order of 20-25 m. The same accuracy can be preserved for eight or more control points and measurement errors of 30-35 m.
Data obtained by HCMM satellite over a complex area in eastern Spain were evaluated and found to be most useful in studying macrostructures in geology and in analyzing marine currents, layers, and areas (although other satellites provide more data). The upper scale to work with HCMM data appears to be 1:2.000.000. Techniques used in preprocessing, processing, and analyzing imagery are discussed as well as methods for pattern recognition. Surface temperatures obtained for soils, farmlands, forests, geological structures, and coastal waters are discussed. Suggestions are included for improvements needed to achieve better results in geographic areas similar to the study area.