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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 1,027 records · Page 57

Design, development, and field demonstration of a remotely deployable water quality monitoring system

A prototype water quality monitoring system is described which offers almost continuous in situ monitoring. The two-man portable system features: (1) a microprocessor controlled central processing unit which allows preprogrammed sampling schedules and reprogramming in situ; (2) a subsurface unit for multiple depth capability and security from vandalism; (3) an acoustic data link for communications between the subsurface unit and the surface control unit; (4) eight water quality parameter sensors; (5) a nonvolatile magnetic bubble memory which prevents data loss in the event of power interruption; (6) a rechargeable power supply sufficient for 2 weeks of unattended operation; (7) a water sampler which can collect samples for laboratory analysis; (8) data output in direct engineering units on printed tape or through a computer compatible link; (9) internal electronic calibration eliminating external sensor adjustment; and (10) acoustic location and recovery systems. Data obtained in Saginaw Bay, Lake Huron are tabulated.

Wallace, J. W.↗

Voyager 2 to make closest encounter with Saturn in August

The planned Voyager 2 Saturn mission is described. Information about Saturn obtained from the Voyager 1 encounter is summarized. Data on the satellites and rings of Saturn are tabulated. The video programming schedule for the Voyager 2 Saturn encounter is given. The Voyager science team is listed.

Source record↗

Effect of sweep and aspect ratio on the longitudinal aerodynamics of a spanloader wing in and out of ground effect

A wind tunnel investigation was conducted in the Langley 4 by 7 meter tunnel to determine the effects of leading edge sweep, aspect ratio, flap deflection, and elevon deflection on the longitudinal aerodynamic characteristics of a span distributed load advanced cargo aircraft (spanloader). Model configurations consisted of leading edge sweeps of 0, 15, 30 and 45 deg and aspect ratios of approximately 2, 4, 6, and 8. Data were obtained for angles of attack of -8 to 18 deg out of ground effect and at angles of attack of -2, 0, and 2 deg in ground effect at Mach number equal 0.14. Flap and elevon deflections ranged from -20 to 20 deg. The data are represented in tabulated form.

Kjelgaard, S. O.↗

Launch summary for 1980

Sounding rockets, artificial Earth satellites, and space probes launched betweeen January 1 and December 31, 1980 are listed. Data tabulated for the rocket launchings show launching site, instruments carried, date of launch, agency rocket identification, sponsoring country, experiment discipline, peak altitude, and the experimenter or institution responsible. Tables for satellites and space probes show COSPAR designation, spacecraft name, country, launch date, epoch date, orbit type, apoapsis, periapsis and inclination period. The functions and responsibilities of the World Data Center and the areas of scientific interest at the seven subcenters are defined. An alphabetical listing of experimenters using the sounding rockets is also provided.

Vostreys, R. W.↗

Masses, radii, temperatures, luminosities and surface compositions of white dwarfs

The masses, radii, temperature, luminosities and compositions of white dwarf stars are discussed, with particular emphasis on those areas in which considerable work remains to be done. It is pointed out that radii for stars of known parallax are available, together with masses and their variance. Consideration is then given to the difficulties involved in the determination of the temperatures of the hottest stars and helium stars by means of Stromgren or multichannel photometry, and it is noted that the frequency of binaries among the hottest degenerates seems too high to be due to chance. Results of IUE observations of the UV spectra of three DA and one DO star are discussed, with attention given to the similarities between UV-derived and ground-based determinations of temperatures and surface gravities. The metal abundances of hydrogen and helium degenerate stars are finally considered, and spectral classes and abundances of the helium atmosphere degenerates are tabulated.

Greenstein, J. L.↗

Ozone contamination in aircraft cabins - Results from GASP data and analyses

The paper reviews results from the NASA Global Atmospheric Sampling Program (GASP) pertaining to the problem of ozone contamination in commercial aircraft cabins. Specifically, analyses of GASP data have (1) confirmed the high ozone levels in aircraft cabins and documented the ratio of ozone inside and outside the cabins of two B747 airliners, including the effects of air conditioning modifications on that ratio; (2) defined ambient ozone climatology at commercial aircraft cruise altitudes, including tabulation of encounter frequency data; and (3) outlined procedures for estimating the frequency of flights encountering high cabin ozone levels using climatological ambient ozone data and verified these procedures against cabin measurements.

Holdeman, J. D.↗

Development of an information data base for watershed monitoring

Landsat multispectral scanner data, Defense Mapping Agency digital terrain data, conventional maps, and ground data were integrated to create a comprehensive information data base (the Image Based Information System), to monitor the water quality of the Lake Tahoe Basin. Landsat imagery was used as the planimetric base to which all other data were registered. A georeference image plane, which provided an interface between all data planes for the Lake Tahoe Basin data base, was created from the drainage basin map. The data base was used to extract each drainage basin for separate display. The Defense Mapping Agency-created elevation image was processed with VICAR software to produce a component representing slope magnitude, which was cross-tabulated with the drainage basin georeference table. Future applications of the data base include the development of precipitation modeling, surface runoff models, and classification of drainage basin cover types.

Smith, A. Y.↗

Heat transfer in a periodic boundary layer near an axisymmetric stagnation point on a circular cylinder

An analysis is presented to investigate the time-mean characteristics of the laminar boundary layer near an axisymmetric stagnation point when the velocity of the oncoming flow relative to the body oscillates. Different solutions are obtained for the small and high values of the reduced frequency parameter. Numerical solutions for the velocity and temperature functions are presented and the wall values of the velocity gradients are tabulated.

Gorla, R. S. R.↗

The albedo of snow for partially cloudy skies

The albedo of snow is defined as the ratio of reflected to incident solar energy, and it is an important parameter in the earth's radiation budget analysis and in the study of snowpack's thermal conditions. An approximate model for calculating the incident spectral flux for partially cloudy skies is presented. The input parameters for the calculation are atmospheric precipitable water, turbidity, ozone content, surface pressure, the optical thickness of clouds, and the grain size of snow crystals. The spectral snow reflectance model considers both specular surface reflection and volumetric multiple scattering. The surface reflection is calculated by using a crystal-shape-dependent bidirectional reflectance distribution function; the volumetric multiple scattering is calculated by using a crystal-size-dependent approximate solution in the radiative transfer equation. The model yields spectral and integrated solar flux and snow reflectance as a function of solar elevation and fractional cloud-cover. The illustrative insolation and albedo values were obtained from spectral reflectance and incident flux for representative parameters of Antarctic coastal regions. A simple relationship between grain size and the overcast albedo was obtained. For a set of grain size and shape, the albedo as a function of solar elevation and fractional cloud cover was tabulated.

Choudhury, B. J.↗

Radar observations of the icy Galilean satellites

It is shown that when combined with previous observations, 12.6 cm radar observations of Europa, Ganymede and Callisto made at the Arecibo Observatory in November 1977 and February 1979 firmly establish the distinguishing radar properties of the satellites: (1) high geometric albedos, (2) circular polarization ratios which anomalously exceed unity, (3) linear polarization ratios of approximately 0.5, and (4) diffuse scattering, which varies with the cosine of the angle of incidence. The weighted-mean values of these properties are tabulated, and it is found that although significant albedo and/or polarization features are common in the radar spectra, the fractional root mean square fluctuations in disk-integrated properties is only about 10%.

Ostro, S. J.↗

Explorer 34 magnetic field measurements near the tail current sheet and auroral activity

Explorer 34 (Imp 4) 2.56 s magnetic data obtained during 131 traversals of the tail current sheet are presented, along with the simultaneous 2.5 min auroral electrojet indices AE and AL. The normal magnetic field satellite crossing times and positions are tabulated for these 131 crossings. Normal magnetic field is defined in the center of the sheet: it is the vector magnetic field at the time of field minimum during the crossing. It is remarkable that the only normal components too large in magnitude to be classified as fine structure occur near the time of onset of an AE event. Cases are discussed where the normal component, defined near the plasma sheet edges, has the opposite sign compared to the normal component defined at the sheet center. For quiet times, the current sheet may be only about 1000 km thick within a 3 earth-radii plasma sheet, and may carry some 10-15% of the total tail current.

Speiser, T. W.↗

Observationally determined silicon II oscillator strengths

Si II oscillator strengths for eight resonance lines from the ground state have been determined using a curve-of-growth analysis of interstellar data from the Copernicus and International Ultraviolet Explorer satellites. The oscillator strengths for 1526 A and 1808 A increase by factors of 3.0 and 1.5, respectively, from previously tabulated values; those for 989 A and 1020 A decrease by factors of 0.55 and 0.60, respectively. These new values result in better silicon abundances for interstellar clouds and resolve a long-standing puzzle in the interpretation of quasar absorption line data.

Shull, J. M.↗

The X-ray spectrum of a hot interstellar plasma

The soft X-ray spectrum of a hot, low density, optically thin plasma in collisional ionization equilibrium is calculated using current atomic data. Many Fe collision strengths differ from previous calculations. The spectra from individual elements are presented for use in abundance determinations from X-ray observations. Collision strengths and line energies, sorted both according to energy and according to ion, are tabulated.

Shull, J. M.↗

Interplanetary gas. XXVII - A catalog of disconnection events in cometary plasma tails

A catalog of 72 disconnection event (DES) in cometary plasma tails is presented as a basic data source for cometary and solar wind analysis. The events span the period 1892-1976, and are characterized on the basis of photographic observations. From the observed kinematics of rejected tails, methods are derived to calculate an estimated time of tail disconnection for each DE, either from the average law of motion for DEs lacking velocity measurements, or from the observed velocities. The geometric circumstances of each DE at the times of separation and observation are also tabulated, and a brief description of each event is presented.

Niedner, M. B., Jr.↗

Application of 'steady' state finite element and transient finite difference theory to sound propagation in a variable duct - A comparison with experiment

Experimental data are presented for sound propagation in a simulated infinite hard wall duct with a large change in duct cross sectional area. The data are conveniently tabulated for further use. The 'steady' state finite element theory of Astley and Eversman (1981) and the transient finite difference theory of White (1981) are in good agreement with the data for both the axial and transverse pressure profiles and the axial phase angle. Therefore, numerical finite difference and finite element theories appear to be ideally suited for handling duct propagation problems which encounter large axial gradients in acoustic parameters. The measured energy reflection coefficient agrees with the values from the Astley-Eversman modal coupling model.

Baumeister, K. J.↗

Heat Pipe Design Handbook: Volume II

This volume consists of a discussion of Fluid Properties (Chapter 1) and a description of the available Heat Pipe Computer Codes (Chapter 2). Appendix A contains appropriate International Scientific Units (SI) and Conversion Factors. The Users Manual for the Heat Pipe Fluid Properties Program (HPF) which is used to generate the fluid property data is presented in Appendix B. Tabulated fluid property data are listed in Appendix C.

Brennan, Patrick J.↗

Two-Dimensional Grids About Airfoils and Other Shapes

GRAPE computer program generates two-dimensional finite-difference grids about airfoils and other shapes by use of Poisson differential equation. GRAPE can be used with any boundary shape, even one specified by tabulated points and including limited number of sharp corners. Numerically stable and computationally fast, GRAPE provides aerodynamic analyst with efficient and consistant means of grid generation.

Sorenson, R.↗