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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 343 records · Page 19
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NASA NTRS1981

Beat frequency interference pattern characteristics study

The frequency spectra and corresponding beat frequencies created by the relative motions between multiple Solar Power Satellites due to solar wind, lunar gravity, etc. were analyzed. The results were derived mathematically and verified through computer simulation. Frequency spectra plots were computer generated. Detailed computations were made for the seven following locations in the continental US: Houston, Tx.; Seattle, Wa.; Miami, Fl.; Chicago, Il.; New York, NY; Los Angeles, Ca.; and Barberton, Oh.

Ott, J. H.↗
NASA NTRS1981

Vacuum ultraviolet light production by nuclear irradiation of liquid and gaseous xenon

Recent Los Alamos investigations suggest that a liquefied noble element may be the long-sought medium for a nuclear-excited laser or flashlamp. Research is needed to confirm this finding and to provide a basis for design and application studies. Quantitative and qualitative information are needed on the nature and behavior of the excited species, the effects of impurities and additives in the liquid phase under nuclear excitation, and the existence and magnitudes of nonlinear effects. Questions that need to be addressed and the most appropriate types of facilities for this task are identified.

Baldwin, G. C.↗
NASA NTRS1979

Airborne surveys of USA urban areas at 121.5/243 MHz

In situ, aircraft flight measurements were made in 1976 and 1977 by NASA of the radio-frequency environment over USA urban areas within the emergency distress search and rescue frequency bands at 121.5 and 243.0 MHz. This paper analyzes test results reported previously for USA East Coast and Midwest flight surveys; presented also are test results obtained in May 1977 for the USA West Coast during the NASA, ASSESS-II, Space Shuttle/Spacelab simulation aircraft flights. The USA West Coast flight include data at 121.5/243 MHz during an extensive series of aircraft passes for the Los Angeles urban area. The USA East Coast/Midwest measurements show correlation with population count.

Taylor, R. E.↗
NASA NTRS1981

Further determination of the characteristics of magnetospheric plasma vortices with Isee 1 and 2

Further studies of the vortices in magnetospheric plasma flow with the Los Alamos Scientific Laboratory/Max-Planck-Institut (LASL/MPI) fast plasma experiment on Isee 1 and 2 have revealed that the pattern of vortical flow has a wavelength of approximately 20-40 earth radii and moves tailward through the magnetosphere at speeds of several hundred kilometers per second. The tendency toward vorticity pervades the total breadth of the plasma sheet tailward of the dawn-dusk meridian. The sense of rotation of the plasma flow (as viewed from above the ecliptic plane) is clockwise in the morning side of the plasma sheet and counterclockwise in the evening side. The sense of rotation in the morning and evening boundary layers is reversed from that in the contiguous regions of the plasma sheet. The occurrence of vortical flow is independent of the level of geomagnetic activity but is associated with long-period geomagnetic pulsations.

Hones, E. W., Jr.↗
NASA NTRS1981

Bi-directional streaming of solar wind electrons greater than 80 eV - ISEE evidence for a closed-field structure within the driver gas of an interplanetary shock

In near time coincidence with the arrival of helium enriched plasma driving the shock wave disturbance of November 12-13, 1978, strong bi-directional streaming of solar wind electrons greater than about 80 eV was observed with Los Alamos instrumentation on ISEE 3. The streaming persisted for many hours simultaneously parallel and anti-parallel to the interplanetary magnetic field which was directed roughly perpendicular to the sun-satellite line. This example of bidirectional streaming cannot be explained by field line connection to the earth's bow shock or the outward propagating interplanetary shock which passed ISEE 3 approximately 16 hours earlier. The event is explained if the local interplanetary field was a part of a magnetic bottle rooted at the sun or a disconnected loop propagating outward.

Bame, S. J.↗
NASA NTRS1981

Satellite estimation of the surface energy balance, moisture availability and thermal inertia

A method for inferring the distribution of surface heat and evaporative fluxes and the ground moisture availability and thermal inertia (ground conductive capacity) is used to analyze two urbanized areas, Los Angeles and St. Louis. The technique employs infrared satellite temperature measurements in conjunction with a one-dimensional boundary-layer model. Results show that there is a marked reduction of evaporation and moisture availability and a corresponding elevation of sensible heat flux over urbanized areas and over cropped areas with low vegetative cover. Conversely, low heat flux and high evaporation characterize vegetated and, especially, forested areas. Warm urban centers appear directly related to a reduction in vegetation, which normally allows for a greater fraction of available radiant energy to be converted into latent heat flux. The distribution of thermal inertia was surprisingly ill-defined and its variation between urban and rural areas was quite small. Thus, the increased heat storage within the urban fabric, which has been proposed as the underlying cause of the nocturnal heat island, may be caused mainly by enhanced daytime surface heating which occurs because of surface dryness, rather than by large spatial variations in the conductivity of the surface.

Carlson, T. N.↗
NASA NTRS1981

Substorm-related plasma sheet motions as determined from differential timing of plasma changes at the ISEE satellites

From an ISEE survey of substorm dropouts and recoveries during the period February 5 to May 25, 1978, 66 timing events observed by the Los Alamos Scientific Laboratory/Max-Planck-Institut Fast Plasma Experiments were studied in detail. Near substorm onset, both the average timing velocity and the bulk flow velocity at the edge of the plasma sheet are inward, toward the center. Measured normal to the surface of the plasma sheet, the timing velocity is 23 + or - 18 km/s and the proton flow velocity is 20 + or - 8 km/s. During substorm recovery, the plasma sheet reappears moving outward with an average timing velocity of 133 + or - 31 km/s; however, the corresponding proton flow velocity is only 3 + or - 7 km/s in the same direction. It is suggested that the difference between the average timing velocity for the expansion of the plasma sheet and the plasma bulk flow perpendicular to the surface of the sheet during substorm recovery is most likely the result of surface waves moving past the position of the satellites.

Forbes, T. G.↗
NASA NTRS1981

Solar wind helium and hydrogen structure near the heliospheric current sheet - A signal of coronal streamers at 1 AU

Solar wind flow properties associated with very low helium to hydrogen abundance ratios have been observed with Los Alamos instruments on IMP 6, 7, and 8 during 1971-1978. A characteristic pattern has been discovered consisting of correlated interplanetary field reversals, high plasma density, low and nearly identical H(+) and He(2+) bulk velocities, low H(+) and He(2+) kinetic temperatures, and minima in their ratios. Because coronal streamers straddle the current sheet close to the sun, the pattern discovered is the 'signal' of a coronal streamer at 1 AU. A superposed epoch analysis of 74 well-defined sector boundary crossings provides verification of the above correlation featuring a pronounced minimum in the helium to hydrogen abundance ratio at the sector boundary passage.

Borrini, G.↗
NASA NTRS1981

Coronal streamers in the solar wind at 1 AU

Virtually all solar wind observing groups have reported substantial variations in the solar wind helium-hydrogen abundance ratio (A(He)). A study of Los Alamos Imp solar wind data has revealed an association between low A(He) and high proton density that occurs at low flow speeds and that is correlated with polarity reversals of the interplanetary magnetic field. The current investigation has the objective to present further examples of the low A(He), high proton density, low speed, magnetic field polarity association, and to document the common occurrence of multiple events lasting approximately 3-7 days. The results are presented of attempts to relate these events directly to maps or isophotes of solar coronal brightness at 1.5 solar radii. The results of the investigation suggest that a substantial fraction of the low-speed solar wind originates in coronal streamers, particularly near solar minimum.

Gosling, J. T.↗
NASA NTRS1981

Texture measurements from Seasat - SAR images for urban land use interpretation

Different grey tones in Seasat Synthetic Aperture Radar (SAR) images for the same type of urban land cover considerably impair the possibilities of establishing automatic classification procedures for these types of data. Since the orientation of the main features like street patterns and buildings with respect to the azimuth angle of the radar antenna is the crucial factor for the observed differences in grey tone, prior information on these elements and special processing of the data would be required to eliminate this effect. Another approach suggested in this paper is to make use of the textural information in the image rather than of its grey tone. For different study sites within the Los Angeles urbanized area texture measures could be derived which result in characteristic values for specific types of land cover and are largely independent of the azimuth angle effect. At the same time the results for the study area indicate an improvement of the overall separability for the different land cover types included in the analysis.

Fasler, F.↗
NASA NTRS1981

Cloud water chemistry and the production of sulfates in clouds

Measurements are presented of the pH and ionic content of water collected in clouds over western Washington and the Los Angeles Basin. Evidence for sulfate production in some of the clouds is presented. Not all of the sulfur in the cloud water was in the form of sulfate. However, the measurements indicate that the production of sulfate in clouds is of considerable significance in the atmosphere. Comparison of field measurements with model results show reasonable agreement and suggest that the production of sulfate in cloud water is a consequence of more than one conversion mechanism.

Hegg, D. A.↗
NASA NTRS1981

RR Lyrae stars - A theoretical study of Bailey types a and b

The full-amplitude behaviour of theoretical models of RR Lyr stars pulsating in the fundamental mode has been explored with the use of Carson's radiative opacities. A detailed comparison of the models with metal-poor RR Lyr stars of Bailey types a and b suggests that these stars have properties that lie somewhere in the following ranges: mass/solar mass = 0.55-0.65, Y = 0.2 0.3, and log (luminosity/solar luminosity) = 1.6-1.7. In obtaining these results, the only data that are used are velocity curves and light curves. Independent information, however, seems to corroborate the values found here. The use of Los Alamos opacities gives somewhat similar results, although the derived masses are smaller by about 20%.

Stothers, R.↗
NASA NTRS1982

Helium, hydrogen, and oxygen velocities observed on ISEE-3

The velocities of hydrogen, helium, and oxygen ions over a full range of solar wind conditions were recorded by the ion composition instrument and Los Alamos National Laboratory plasma instrument aboard the International Sun Earth Explorer. Interspecie velocity differences were observed frequently. For solar wind velocities between 300 and 400 km s(-1) the helium velocity exceeded the hydrogen velocity by 5 km s(-1) the average difference was 14 km s(-1), however no evidence was found for a nonzero average velocity difference between helium and oxygen ions even at the higher velocities. Velocity differences were examined in a number of streams and across a number of interplanetary shocks. Generally helium hydrogen velocity differences are bounded by the Alfven speed. Velocity differences show abrupt changes across interplanetary discontinuities, presumably tangential. The electrostatic potential change across a shock produces differences between the velocities of ions having different charges.

Ogilvie, K. W.↗
NASA NTRS1982

Community noise

Airport and community land use planning as they relate to airport noise reduction are discussed. Legislation, community relations, and the physiological effect of airport noise are considered. Noise at the Logan, Los Angeles, and Minneapolis/St. Paul airports is discussed.

Bragdon, C. R.↗
NASA NTRS1982

Plasma electron signature of magnetic connection to the earth's bow shock - ISEE 3

New observations of bowshock modified electron velocity distribution for upstreams are investigated using the Los Alamos ISEE 3 electron analyzer. Examples of two-dimensional electron distributions observed when ISEE 3 magnetically connected to the bowshock are presented, and the velocity moments are determined. The origin of the enhanced backstreaming electron fluxes and their likely effects on the upstream microturbulence spectrum are interpreted. A nearly isotropic component of back-streaming shock-heated electrons is found with energies at least as high as 1 keV. Phase-space density of the low energy parts of distributions measures well within the boundaries of accessibility and is observed to be depressed. Such distributions are likely to result from the direct sampling of electrons originating within the forward edge of the earth's bowshock, and may be unstable to whistler waves.

Feldman, W. C.↗
NASA NTRS1982

PV large systems project

Near term photovoltaic central-station markets are analyzed. Cost effectiveness of photovoltaic plants is determined in terms of reduction of oil consumption. The breakeven photovoltaic system cost vs oil-steam power generation is given. The value of photovoltaic power plants in Southern California and in Los Angelos is given in terms of fuel savings and capacity value. The potential value of third party financing, facilitated by Federal and state tax incentives is analyzed.

Leonard, S. L.↗
NASA NTRS1982

Solar wind iron abundance variations at solar wind speeds up to 600 km s sup -1, 1972 to 1976

The Fe/H ratios in the peaks of high speed streams (HSS) were analyzed during the decline of Solar Cycle 20 and the following minimum (October 1972 to December 1976). The response of the 50 to 200 keV ion channel of the APL/JHU energetic particle experiment (EPE) on IMP-7 and 8 was utilized to solar wind iron ions at high solar wind speeds (V or = 600 km/sec). Fe measurements with solar wind H and He parameters were compared from the Los Alamos National Laboratory (LANL) instruments on the same spacecraft. In general, the Fe distribution parameters (bulk velocity, flow direction, temperature) are found to be similar to the LANL He parameters. Although the average Fe/H ration in many steady HSS peaks agrees within observational uncertainties with the nominal coronal ratio of 4.7 x 0.00001, abundance variations of a factor of up to 6 are obtained across a given coronal-hole associated HSS.

Mitchell, D. G.↗
NASA NTRS1981

Potentials for change detection using Seasat synthetic aperture radar data

Synthetic aperture radars (SAR) image from a non-nadir position. Thus the orientation of the target and sensor to one another is of paramount importance. This has posed problems for data interpretation and with the potentials of radar data for change detection studies. It is possible to use Seasat radar data for change detection even though the look directions are fixed for each location. Especially in areas with repeated coverage on descending or ascending orbits or where the terrain is flat and the targets nonoriented, coverage may be sufficient to provide data for change detection. Examples of Los Angeles and the Everglades of Florida help develop and support the argument.

Bryan, M. L.↗