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At least 577 records · Page 32
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Use of ERTS imagery in air pollution and marine biology studies, tasks 1 through 3

There are no author-identified significant results in this report. The general suitability of ERTS imagery in detecting ground originated air pollution has proved to be excellent. The quality and resolution exceeded expectations and has permitted in some instances location of point sources to within a thousand feet. Suitable techniques have not yet been developed for determining or measuring area and line sources of air pollution. A major problem has been cloud cover that has persisted over the area of primary interest, the Chesapeake Bay. Work has been completed on mounting the shipboard transmissometer which will be used for investigations to relate the chlorophyll and suspended sediment content in the waters of the Lower Chesapeake Bay to ERTS-1 imagery. Water sampling, plankton analysis, and preparations for sea collection of water truth along the eastern continental shelf of the U.S. have been completed for use in comparisons with ERTS-1 data.

Copeland, G. E.↗
NASA NTRS1972

A Multi-ring Ionospheric Plasma Probe

An ionospheric plasma probe was constructed which consists of a long cylinder with the end facing the flow closed by an end plate made up of multiple annular rings and a center disk. A theoretical argument is given which yields the plasma potential and electron temperature in terms of known plasma parameters and the currents to the various rings of the end plate. This probe was successfully operated in an ionospheric flow simulation facility and the resulting plasma potential is in excellent agreement with the traditional Langmuir analysis (1.22 volts).

Sheldon, J. W.↗
NASA NTRS1973

Facilitating the exploitation of ERTS imagery using snow enhancement techniques

The author has identified the following significant results. EarthSat has established an effective mail-based method for obtaining timely ground truth (snow depth) information over an extensive area. The method is both efficient and inexpensive compared with the cost of a similarly scaled direct field checking effort. Additional geological information has been acquired which is not shown in geological maps in the area. Excellent quality snow-free ERTS-1 transparencies of the test areas have been received and are being analyzed.

Wobber, F. J.↗
NASA NTRS1972

To develop a land use peak runoff classification system for highway engineering purposes

The author has identified the following significant results. Bands 6 and 7 are excellent for the detection of surficial water and swampy sites having the water table at or near the ground surface. Water bodies less than five acres in extent have been identified. Color composites should provide considerably more data for visual analysis than the black and white products currently available to this investigation.

Stoeckeler, E. G.↗
NASA NTRS1972

The accuracy of geopotential solutions from resonant satellite data

Tracking data from a significant number of strongly resonant satellites have not yet been incorporated into recent comprehensive geopotential solutions. This data furnishes excellent comparative and absolute tests of these solutions for resonant coefficients of order (m) 2, 3, 4, 9 and 14. Tracking arcs of from 1 month to 6 years are examined on seven satellites of 1 rev/day, three of 2 revs/day, and one each of 9 and 14 revs/day. Current values for these fully normalized resonant coefficients as judged by this independent and sensitive data, range in accuracy from 2 x 10 to the minus 8th power to 5 x 10 to the minus 8th power. This represents an increase in accuracy by a factor from 3 to 5 over solutions current in the mid 1960's.

Wagner, C. A.↗
NASA NTRS1973

Labyrinth seal testing for lift fan engines

An abradable buffered labyrinth seal for the control of turbine gas path leakage in a tip-turbine driven lift fan was designed, tested, and analyzed. The seal configuration was not designed to operate in any specific location but was sized to be evaluated in an existing test rig. The final sealing diameter selected was 28 inches. Results of testing indicate that the flow equations predicted seal air flows consistent with measured values. Excellent sealing characteristics of the abradable coating on the stator land were demonstrated when a substantial seal penetration of .030 inch into the land surface was encountered without appreciable wear on the labyrinth knife edges.

Dobek, L. J.↗
NASA NTRS1970

An Exercise Prescription Intervention Program with Periodic Ergometric Grading

A long term exercise prescription type of physical conditioning program has been available to executive personnel of the NASA Manned Spacecraft Center for the past two years. Periodic ergometric testing with a heart rate controlled, automatically programmed, bicycle ergometer is used to follow the individual's progress and appropriately alter his exercise prescription from time to time. Such a program appears feasible, and acceptance is excellent, dropout rates small and periodic testing participation good. Subjects training diligently can maintain satisfactory levels of conditioning.

Owen, C. A.↗
NASA NTRS1972

A theoretical study of mixing downstream of transverse injection into a supersonic boundary layer

A theoretical and analytical study was made of mixing downstream of transverse hydrogen injection, from single and multiple orifices, into a Mach 4 air boundary layer over a flat plate. Numerical solutions to the governing three-dimensional, elliptic boundary layer equations were obtained using a general purpose computer program. Founded upon a finite element solution algorithm. A prototype three-dimensional turbulent transport model was developed using mixing length theory in the wall region and the mass defect concept in the outer region. Excellent agreement between the computed flow field and experimental data for a jet/freestream dynamic pressure ratio of unity was obtained in the centerplane region of the single-jet configuration. Poorer agreement off centerplane suggests an inadequacy of the extrapolated two-dimensional turbulence model. Considerable improvement in off-centerplane computational agreement occured for a multi-jet configuration, using the same turbulent transport model.

Baker, A. J.↗
NASA NTRS1973

Geology of Utah and Nevada by ERTS imagery

The author has identified the following significant results. Two ancient watercourses have been observed on ERTS-1 imagery. These lie in the Waterpocket Fold area, north of the Marble Canyon section of the Colorado River, in Arizona and Utah. A third old watercourse of interest is an ancient canyon of the Colorado and is located on image no. 1156-17260. Image no. 1051-17414 contains some very useful information concerning the hydrology, sedimentology, and biology of Great Salt Lake and Bear Lake in Utah. In Great Salt Lake, there is a sharp line between the portion of the lake north of the railroad causeway and that south of the causeway. There is a marked difference in salinity across the causeway, and this is reflected in different algal species. On the same image, sediment plumes in Bear Lake clearly delineate the circulation pattern, and provide excellent indications of bottom contours over much of the area. Image no. 1051-17420 contains part of Great Salt Lake and all of Utah Lake. The latter displays a very interesting surface pattern which is probably due to an algal bloom which has been swirled into a spiral by the circulation of the lake.

Jensen, M. L.↗
NASA NTRS1973

Determine the utility of ERTS-1 imagery in the preparation of hydrologic atlases of arid land watersheds

The author has identified the following significant results. The 9x9-inch transparencies from the ERTS-1 system seem to have better contrast in vegetation and drainage features than the 70-mm transparencies. This imagery can be magnified about eight times before it becomes excessively grainy. Imagery in band 7 appears to be the best single band product for viewing landform-water complexes. Band 5 best defines vegetation patterns. Multispectral color-additive viewing would appear to improve the separation of vegetation types where the vegetation exhibits moderate to strong infrared reflectance. Multispectral viewing did not appear to improve relief of drainage channel detail. False-color aerial infrared photographs at a scale of 1:120,000 for the Utah test site are excellent quality and can be magnified as much as 15 times without serious loss of contrast or excessive fuzziness. In desert areas with sparse to moderate shrub cover, the contrast between the soil background and the plant cover is so low that texture cannot be seen, even under high magnification. In areas of higher rainfall during the summer it is possible to discriminate coniferous and deciduous trees, grass, and shrub communities and to identify different rangeland treatment practices.

Shown, L. M.↗
NASA NTRS1973

Sketch on the structural geology and vulcanism in the Central High Plateau of the Bolivian Andes

The author has identified the following significant results. The Earth Resources Technology Satellite Program has as an objective the development of tectonic maps for Bolivia. Maps were prepared using the images of ERTS-1 in a preliminary study of alignments observed and rapidly interpreted in images 1010-14033-3-4-5-6-7 on a scale of 1:1,000,000, and later verified on the ground with corresponding fault zones. This information was not shown on existing geologial maps. The ERTS-1 imagery was used in volcanology research for drawing the regional limits of volcanic formations as soon as the alignment and the extent of the volcanoes could be determined. The extensive coverage of ERTS-1 images provides an excellent opportunity for developing studies of regional structures.

Brockmann, C. E.↗
NASA NTRS1973

Mapping southern Atlantic coastal marshland, South Carolina-Georgia, using ERTS-1 imagery

The author has identified the following significant results. Southeastern coastal marshes are among the most extensive and productive in the United States. A relatively low cost, moderately accurate method is needed to map these areas for management and protection. Ground based and low altitude aircraft methods for mapping are time consuming and quite expensive. The launch of NASA's ERTS-1 has provided an opportunity to test the feasibility of mapping wetlands using small scale imagery. The test site selected was an area from the South Carolina border to Saint Catherine's Island, Georgia. Results of the investigation indicate that the following may be ascertained from ERTS-1 imagery: (1) upper wetland boundary; (2) drainage pattern in the wetland; (3) plant communities such as Spartina alterniflora, Spartina patens, Juncus roemerianus; (4) ditching activities associated with agriculture; (5) lagooning for water-side home development. Conclusions are that ERTS-1 will be an excellent tool for many types of coastal wetland mapping.

Anderson, R. R.↗
NASA NTRS1973

Gyrator employing field effect transistors

A gyrator circuit of the conventional configuration of two amplifiers in a circular loop, one producing zero phase shift and the other producing 180 deg phase reversal is examined. All active elements are MOS field effect transistors. Each amplifier comprises a differential amplifier configuration with current limiting transistor, followed by an output transistor in cascode configuration, and two load transistors of opposite conductivity type from the other transistors. A voltage divider control circuit comprises a series string of transistors with a central voltage input to provide control, with locations on the amplifiers receiving reference voltages by connection to appropriate points on the divider. The circuit produces excellent response and is well suited for fabrication by integrated circuits.

Hochmair, E. S.↗
NASA NTRS1973

Utilization of ERTS-1 data to monitor and classify eutrophication of inland lakes

The author has identified the following significant results. Bands 6 and 7 have fine structure as obtained by proper selection of digital levels in processing the CCT's. This is contrary to the imagery density received. This means that the small lakes can be classified in IR for different types of water masses. At least four distinct water masses have been determined for test lakes. They are shoreline, shallow water, and two deep waters. One deep water is patchy and presents difficulty in training set selection. The excellent weather and a completely successful field test form a significant happening. It required 12 orbits over the test area before perfect weather occurred.

Chase, P. E.↗
NASA NTRS1973

Addition of three-dimensional isoparametric elements to NASA structural analysis program (NASTRAN)

Implementation is made of the three-dimensional family of linear, quadratic and cubic isoparametric solid elements into the NASA Structural Analysis program, NASTRAN. This work included program development, installation, testing, and documentation. The addition of these elements to NASTRAN provides a significant increase in modeling capability particularly for structures requiring specification of temperatures, material properties, displacements, and stresses which vary throughout each individual element. Complete program documentation is presented in the form of new sections and updates for direct insertion to the three NASTRAN manuals. The results of demonstration test problems are summarized. Excellent results are obtained with the isoparametric elements for static, normal mode, and buckling analyses.

Field, E. I.↗
NASA NTRS1973

NASA hydrogen maser accuracy and stability in relation to world standards

Frequency comparisons were made among five NASA hydrogen masers in 1969 and again in 1972 to a precision of one part in 10 to the 13th power. Frequency comparisons were also made between these masers and the cesium-beam ensembles of several international standards laboratories. The hydrogen maser frequency stabilities as related to IAT were comparable to the frequency stabilities of individual time scales with respect to IAT. The relative frequency variations among the NASA masers, measured after the three-year interval, were 2 + or - 2 parts in 10 to the 13th power. Thus time scales based on hydrogen masers would have excellent long-term stability and uniformity.

Peters, H. E.↗
NASA NTRS1973

A mechanical property and stress corrosion evaluation of 431 stainless steel alloy

The mechanical properties of type 431 stainless steel in two conditions: annealed bar and hardened and tempered bar are presented. Test specimens, manufactured from approximately 1.0 inch (2.54 cm) diameter bar stock, were tested at temperatures of 80 F (+26.7 C), 0 F (-17.8 C), -100 F (-73 C), and -200 F (-129 C). The test data indicated excellent tensile strength, notched/unnotched tensile ratio, ductility, shear, and impact properties at all testing temperatures. Results of the alternate immersion stress corrosion tests on stressed and unstressed longitudinal tensile specimens 0.1250 inch (0.3175 cm) diameter and transverse C-ring specimens, machined from 1.0 inch (2.54 cm) diameter bar stock, indicated that the material is not susceptible to stress corrosion cracking when tested in a 3.5 percent NaCl solution for 180 days.

Montano, J. W.↗
NASA NTRS1972

Microbial response to space environment, part B

The performance of the microbial response to space environment experiment is considered excellent by all investigators. For most microbial systems, only preliminary survival data are available at this time. None of the available data indicate space flight-mediated changes in cell viability or recovery. One quite important observation has been made at this early date, however. The eggs produced after mice had been infected with N. dubius larvae demonstrated a significant decrease in hatchability when compared to identical ground controls. Except for the fact that the Apollo 16 flight larvae had been on board the command module, treatment of the flown larvae and ground control larvae was the same; neither had been exposed to UV irradiation. The significance and implications of this finding are currently being studied.

Taylor, G. R.↗