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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 181 records · Page 10

Using Landsat digital data to detect moisture stress

A technique utilizing transformed Landsat digital data for detection of agricultural drought was empirically defined during the 1976 South Dakota drought. During 1977, the procedure was expanded to the Great Plains for evaluation as a technique for detecting and monitoring vegetative water stress over large areas. The technique, Green Index Number (GIN), uses Landsat digital data from 5 by 6 nautical mile sampling frames (segments) to indicate when the vegetation within the segment is undergoing drought. At known growth stages for wheat, segments were classified as drought or non-drought areas. The remote-sensing-based information was compared to a weekly ground-based index (Crop Moisture Index) provided by the United States Department of Commerce. This comparison demonstrated a high degree of agreement between the 18-day remote sensing technique and the ground-based weekly data. Maps based on GIN of parts of the USSR and Australia were produced with a two-week lag and later compared with other crop assessments of crop conditions in these areas. These maps were judged to be in general agreement with the other data sources.

Thompson, D. R.↗

The search and rescue satellite mission - A basis for international cooperation

The use of geostationary and polar-orbiting satellites to monitor and locate signals of the Emergency Locator Transmitter (ELT) and Emergency Position Indicating Radio Beacon (EPIB) of general aviation aircraft and inspected marine vessels respectively is described. The joint U.S. Canada/France SARSAT demonstration program will require a minimum of four minutes of mutual visibility of distress transmitter, local user terminal and satellite to obtain a location by Doppler tracking. The program consisting of placing instrumentation on-board three of the Tiros-N series of NOAA operational satellites is attracting interest also from other countries including the USSR, Norway, Australia, and Japan.

Redisch, W. N.↗

The Large Area Crop Inventory Experiment /LACIE/ - A summary of three years' experience

Aims, history and schedule of the Large Area Crop Inventory Experiment (LACIE) conducted by NASA, USDA and NOAA from 1974-1977 are described. The LACIE experiment designed to research, develop, apply and evaluate a technology to monitor wheat production in important regions throughout the world (U.S., Canada, USSR, Brasil) utilized quantitative multispectral data collected by Landsat in concert with current weather data and historical information. The experiment successfully exploited computer data and mathematical models to extract timely corp information. A follow-on activities for the early 1980's is planned focusing especially on the early warning of changes affecting production and quality of renewable resources and commodity production forecast.

Erb, R. B.↗

The magnetic fields of Mercury, Mars, and moon

Mariner observations have shown a significant global magnetic field at Mercury with a dipole moment at a tilt of 14 + or - 5 deg relative to the normal of the orbit plane. A presently active dynamo is the most likely origin for the planet's magnetic field. Limited evidence for an intrinsic magnetic field on Mars was obtained by USSR spacecraft in 1971 and 1974. The Martian magnetic field, if it exists, may result from either remanent magnetism or an active dynamo. On the moon, local magnetic fields have been detected by the Apollo and Lunokhod missions, but no global correlation of the steady state values has been noted.

Ness, N. F.↗

Historical development of worldwide supersonic aircraft

Aerodynamic problems in the development of supersonic aircraft, their solutions, and innovative design features are presented. Studies of compressibility, introduction of jets, supersonic phenomena, transonic drag and lift, longitudinal and directional stability, dynamic pressure fields, and advent of the supersonic fighter are discussed. The flight research aircraft such as the Bell X-1 and the Douglas-558, the century series models, reconnaissance aircraft, the multimission tactical fighter, and the current generation fighters such as F-16 and F-18 are described. The SCAT program is considered, along with supersonic developments in Great Britain, France, and USSR. It is concluded that the sonic boom still appears to be an inherent problem of supersonic flight that particularly affects overland commercial flight, and efforts continue for increased efficiency for economic and performance gains and increased safety for military and civilian aircraft.

Spearman, M. L.↗

Is lunar ranging a viable component in a next-generation earth rotation service

The present actuality of the application of lunar laser ranging to the problem of the experimental determination of earth's rotation is discussed. The current status of the 'Earth Rotation from Lunar Distances' (EROLD) program is briefly summarized. Some results obtained up to 1978 for UT0 determinations are noted, and the situation regarding stations in Australia, France, West Germany, Japan, the United States, and the USSR is reviewed.

Mulholland, J. D.↗

Density models for the upper atmosphere

Three contemporary atmospheric density models which are candidates for meeting the current orbit computation requirements are compared. The models considered are the analytic Jacchia-Roberts model, the modified Harris-Priester model, and the USSR Cosmos satellite derived density model. All of these models can be said to be quasi-dynamic representations of the atmospheric density. The time dependent variations in the model density profiles are determined by both the evaluation of explicit continuous functions of time and by the input of time varying parameters to algorithms. The computation characteristics of each of the models are compared and a modification to the modified Harris-Priester model is proposed which improves its ability to represent the diurnal variation in the atmospheric density.

Dowd, D. L.↗

Does ELF chorus show evidence of power line stimulation

A study to determine the effect of power line radiation on the stimulation of the ELF chorus detected on OGO-5 is presented. Chorus shows a maxima over the Eastern USSR, Greenland, and Central Siberia and minima over central and Eastern Canada, a distribution different than the OGO-3. This discrepancy is explained as due to data oversampling in the previous study; the OGO-5 data were reanalyzed with the oversampling removed, showing that none of the longitudinal maxima or minima are statistically significant. It is concluded that there is no significant correlation between longitude and chorus occurrence which implies that there is little or no evidence of power line harmonic radiation effects on chorus triggering.

Tsurutani, B. T.↗

JOB BUILDER remote batch processing subsystem

The functions of the JOB BUILDER remote batch processing subsystem are described. Instructions are given for using it as a component of a display system developed by personnel of the System Programming Laboratory, Institute of Space Research, USSR Academy of Sciences.

Orlov, I. G.↗

Linking of the BENSON graph-plotter with the Elektronika-1001 computer

A device, developed by the Institute of Space Research of the Academy of Sciences of the USSR, for linking the Elektronika-100I computer with the BENSON graph-plotter is described. Programs are compiled which provide display of graphic and alphanumeric information. Instructions for their utilization are given.

Valtts, I. Y.↗

Impact of improved information on the structure of world grain trade

The benefits to be derived by the United States from improvements in global grain crop forecasting capability are discussed. The improvements in forecasting accuracy, which are a result of the use of satellite technology in conjunction with existing ground based estimating procedures are described. The degree of forecasting accuracy to be obtained from satellite technology is also examined. Specific emphasis is placed on wheat production in seven countries/regions: the United States; Canada; Argentina; Australia; Western Europe; the USSR; and all other countries in a group.

Source record↗

High-resolution observations of the QSO 3C 345 at 1.3 centimeters

High-resolution VLBI observations made at a frequency of 22.235 GHz of the quasar 3C 345 are discussed. Antennas located at the Crimean Astrophysical Observatory, USSR; Onsala, Sweden; Effelsberg, West Germany; and the Haystack Observatory, Massachusetts were employed at 4-min integration times to provide baselines ranging up to 5.5 x 10 to the 8th wavelengths. About 40% of the total flux density of 7.85 Jy, observed in November 1977, and 8.05 Jy, observed in October 1978, is found to originate in an unresolved component of the quasar core in a region less than 0.1 milliarcsec in diameter. The elongated jet-like component of the quasar is observed to contain several peaks of emission extending up to 6 milliarsec from the core which decreased in extent between the two observations.

Baath, L. B.↗

Sample selection in foreign similarity regions for multicrop experiments

The selection of sample segments in the U.S. foreign similarity regions for development of proportion estimation procedures and error modeling for Argentina, Australia, Brazil, and USSR in AgRISTARS is described. Each sample was chosen to be similar in crop mix to the corresponding indicator region sample. Data sets, methods of selection, and resulting samples are discussed.

Malin, J. T.↗

An intercomparison of ground-based total ozone instruments

Five ground-based total ozone spectrophotometers were intercompared at Wallops Island, VA between October 1979 and January 1981. The tests were conducted to evaluate the stability and accuracy of each instrument over an extended time period. Acceptable performance regarding these two characteristics is essential if an instrument is to be useful in field measurements and network monitoring of the atmospheric total ozone content. The Dobson spectrophotometer was used as the standard of comparison for the Brewer grating spectrophotometer, the USSR M-83 ozonometer, the Canterbury filter photometer, and the SenTran filter photometer. The grating instrument was found to be potentially the equal of the Dobson but was subject to unreliable performance by its rather sophisticated electronic components. The filter photometers performed acceptably for short periods but filter aging and eventual degradation rendered both units unusable before the end of the intercomparison. Finally, the M-83 results were found to be in acceptable agreement with the Dobson throughout the period when certain qualifications are invoked. The accuracy of a single M-83 ozone measurement may be low. Averages tend to improve its agreement with the Dobson.

Parsons, C. L.↗

Preliminary results of an intercomparison of total ozone spectrophotometers

Preliminary results from an intercomparison of five total ozone spectrophotometers are presented. These are the Dobson spectrophotometer, the USSR M-83 ozonometer, the Canterbury filter photometer, the SenTran Company filter photometer, and the Brewer grating spectrophotometer. The pertinent characteristics of each are described, and conclusions are drawn about the agreement of each instrument's measurements with the Dobson's values over a time period of nearly one year. A discussion of the importance of calibration and long-term stability and reliability is included.

Parsons, C. L.↗

The water factor in harvest-sprouting of hard red spring wheat

Sprouting in unthreshed, ripe, hard red spring wheat (Triticum aestivum L.) is induced by rain, but sprouting does not necessarily occur because the crop is wetted. The spike and grain water conditions conducive to sprouting were determined in a series of laboratory experiments. Sprouting did not occur in field growing wheat wetted to 110% water concentration until the spike water concentration was reduced to 12% and maintained at this concentration for 2 days before wetting. When cut at growth stage 11.3, Feekes scale, Saratovskaya 20 (USSR) sprouted after 4 days drying, Olaf and Alex between 7 and 15 days drying and Columbus, recognized for its resistance to harvest time sprouting, after more than 15 days drying. Sprouting potential was enhanced after 4 wetting drying cycles in which any wetted interval was too brief to permit sufficient water imbibition to initiate sprouting. At harvest ripeness, grain water concentration exceeded spike water concentration by 0.7 percentage units. Following 6 months storage, 20% of the kernels in 300 spike bundles (simulating windrows) sprouted within 28 hrs after initiation of wetting to saturation (150% water concentration). Ninety percent sprouting occurred within 8 days in bundles maintained at 75% water concentration and higher, but less sprouting occurred in bundles dried to 50% water concentration before resaturation.

Bauer, A.↗

Radiation exposures during space flight and their measurement

The paper reviews radiation exposures recorded during space flights of the U.S. and USSR. Most of the data are from manned missions and include discussion of absorbed dose and dose rates as a function of parameters such as altitude, inclination, spacecraft type and shielding. Preliminary data exist on the neutron and HZE-particle component, as well as the LET spectra. For low earth-orbit missions, the dose encountered is strongly altitude-dependent, with a weaker dependence upon inclination. The doses range from about 6 millirad per day for the Space Transportation System No. 3 flight to about 90 mrad per day for Skylab. The effective quality factor (QF) for the near-earth orbits and free space has been estimated to be about 1.5 and about 5.5 respectively. Complete shielding from the galactic cosmic rays does not appear practical because of spacecraft weight limitations.

Benton, E. V.↗