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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 451 records · Page 25
All sourcesNASA NTRSDOE OSTI
NASA NTRS1983

Transport properties for the nitrogen system - N2, N, N(+) and E

The transport properties of the 'nitrogen system' (N2, N, N(+), and e) are important in a variety of applications, including atmospheric entry of the Shuttle and other re-entry vehicles. The kinetic theory of gases has been used to calculate the conductive transport properties for this system. The best available two-body interaction potentials have been used to calculate the transport collision integrals for each of the ten interactions which can occur in this system. Results are presented for the pure species and for the gas mixture from 600K-14000K.

Biolsi, L.↗
NASA NTRS1983

Solar irradiance variations. II - Analysis of the extreme ultraviolet measurements onboard the Atmosphere Explorer E satellite

Five of the extreme ultraviolet channels (L-alpha, L-beta, He I, He II, Fe XV) measuring irradiance fluctuations on board the AE-E satellite between 1977 and 1980 have been studied in detail. It is shown that the daily variations correspond very closely to the daily variations in solar radio emission (F10.7), but that the UV data are afflicted with serious and to date unrecognized calibration changes during the period of operation of the instruments. In order to correct for these changes, a statistical analysis is carried out, and a set of corrections to the raw data is suggested. The resulting, now uniform, data are then compared with rocket measurements (L-alpha) and data acquired onboard the AE-C satellite (L-beta). Finally the remaining discrepancies are discussed. After concluding that they are below the overall level of uncertainties, a first-order 10-year run of EUV irradiances derived from F10.7 data is proposed. This estimate includes the ratio of irradiance levels between the maxima of solar cycles 20 and 21 and the intervening minimum.

Oster, L.↗
NASA NTRS1984

Investigation of Aeronomic Processes on the Basis of Ionospheric Sporadic E

A method by means of which the characteristics of atmospheric turbulence can be determined is discussed. Turbulent diffusivity deduced from ionospheric sporadic E in different altitudes above the ionospheric stations at Bekescsaba and Juliusrah are given. Seasonal variations in different altitudes above Bekescsaba are shown. An attempt was made to determine the variation of the turbulent diffusivity during and after geomagnetic disturbances by computing the horizontal wind velocity from the thermal wind equation. It is argued that the change of the turbulent diffusivity below the turbopause is opposed to that above the turbopause.

Bencze, P.↗
NASA NTRS1982

The E-ring of Saturn

The origin of the E-ring of Saturn and its relationship to Enceladus is discussed. It is proposed that the ring is formed as a consequence of micrometeoritic and meteoritic bombardment of Enceladus. It is shown that the mass reaching the ring replaces that lost by erosion, drag and other mechanisms. The effect of the presence of amorphous ice and the possible opposition effect is indicated.

Smoluchowski, R.↗
NASA NTRS1985

Measurements of the E region neutral wind field

The neutral E-region wind field was measured at Calgary, Canada (51 N, 114 N) during 75 nights in 1982. Observations of the Doppler shift of the 5577-A emission line of atomic oxygen using a Fabry-Perot interferometer were converted to horizontal wind vectors. From the analysis of the data, four categories of wind characteristics were identified. In order of increasing magnetic activity these categories are: (1) wind field mostly variable in space and time; (2) predominantly equatorward flow throughout the night, (3) predominantly poleward flow throughout the night and (4) north-westward flow before midnight and southward after midnight. The wind magnitude was also variable and on some disturbed days exceeded 200 m/s.

Cogger, L. L.↗
NASA NTRS1985

Inclusion of exact exchange in the noniterative partial-differential-equation method of electron-molecule scattering - Application to e-N2

The noniterative partial-differential-equation (PDE) approach to electron-molecule scattering of Onda and Temkin (1983) is modified to account for the effects of exchange explicitly. The exchange equation is reduced to a set of inhomogeneous equations containing no integral terms and solved noniteratively in a difference form; a method for propagating the solution to large values of r is described; the changes in the polarization potential of the original PDE method required by the inclusion of exact static exchange are indicated; and the results of computations for e-N2 scattering in the fixed-nuclei approximation are presented in tables and graphs and compared with previous calculations and experimental data. Better agreement is obtained using the modified PDE method.

Weatherford, C. A.↗
NASA NTRS1985

The new eclipsing magnetic binary system E 1114 + 182

A comprehensive analysis of E 1114 + 182, the first eclipsing AM Herculis binary system and the shortest-period eclipsing cataclysmic variable known, is presented. The time-resolved X-ray observations which led to the system's recognition as an AM Her system with a roughly 90 minute orbital period are reported. The current optical photometric and polarimetric ephemeris and a description of the system's phase-modulated properties are given. The detailed photometric eclipse profile and the highly variable spectroscopic behavior are addressed. This information is used to determine systemic parameters and derive new information on the line emission regions. The data put severe constraints on current torque models for keeping the binary and white dwarf rotation in phase.

Biermann, P.↗
NASA NTRS1985

The stratospheric aerosol particle measurement by balloon at Syowa Station (69.00 deg S, 39.35 deg E): Outline of special sonde (rubber) campaign JARE 24

During the period of AMA (Antarctic Middle Atmosphere), various style balloons were used to measure atmospheric parameters at Syowa Station (69.00 deg S, 39.35 deg E), Antarctica. The measurements which were made using balloons specially designed to monitor stratospheric aerosol particles are discussed. This type balloon was first used by JARE (Japan Antarctic Research Expedition) 24th Team in 1983. Until that time, the Japan Antarctic Research Expedition Team had been using only a large plastic balloon to monitor various minor constituents in the stratosphere. The plastic balloon was very useful, but it took a long time to arrange a balloon launching. Additionally, launching time strongly depended on weather conditions. A timely launching of the balloon was carried out with this specially designed sonde.

Iwasaka, Y.↗
NASA NTRS1985

Studies of electron-polyatomic-molecule collisions Applications to e-CH4

The first application of the Schwinger multichannel formulation to low-energy electron collisions with a nonlinear polyatomic target is reported. Integral and differential cross sections are obtained for e-CH4 collisions from 3 to 20 eV at the static-plus-exchange interaction level. In these studies, the exchange potential is directly evaluated and not approximated by local models. An interesting feature of the small-angle differential cross section is ascribed to polarization effects and not reproduced at the static-plus-exchange level. These differential cross sections are found to be in reasonable agreement with existing measurements at 7.5 eV and higher energies.

Lima, M. A. P.↗
NASA NTRS1985

Spectrophotometry of peculiar B and A stars. XVIII - The helium rich variable stars HR 1890, Sigma Orionis E, and HD 37776

Optical region spectrophotometry at 3300-7850 A has been obtained for three helium rich stars, HR 1890, Sigma Ori E, and HD 37776, of the Orion OB1 Association. New uvby-beta photometry of HR 1890 and HD 37776 as well as published data are also used to investigate the variability of these stars. A new period of 1.53862 days was determined for HD 37776. For all three stars H-beta varies in antiphase with strong He I lines. The spectrophotometric bandpass containing the strong He I line at 4471 A varies in phase with the R index of Pedersen and Thomsen (1977). Evidence is found for weak absorption features which appear to be an extension of the 5200 A feature seen in cooler CP stars.

Adelman, S. J.↗
NASA NTRS1985

Comparative in situ studies of the unstable day-time equatorial E-region

Three in situ rocket observations of electrostatic fluctuations which characterize the strong, mild, and weak day-time unstable E-region are compared. The fluctuations are analyzed in relation to the ambient electron density gradients, the measured or inferred drift velocities and, where possible, to simultaneous VHF backscatter radar measurements. Based on these parameters, the linear dispersion relation is solved to find the range of altitudes and wavenumbers for which the growth rate indicates that instability will occur. These computations are compared with actual observations of the irregularities. How well the linear growth rate predicts the altitude range of the unstable layer, and to what extent the regime of the unstable wavenumbers is reflected in the spectra of the irregularities, is shown. Overall, the agreement is good.

Pfaff, R. F.↗
NASA NTRS1986

Compressible laminar boundary layer with real gas effects for flight conditions to M(e) = 8 and T(o) = 2500 K

One of the problems for the hypersonic flights is the lack of accurate methods for predicting the boundary layer parameters at high Mach numbers and temperatures. At high Mach numbers and temperatures, the real gas effects should be included in calculations of the compressible laminar and turbulent boundary layers. By introducing the Mangler-Levy-Lees transformation, the compressible laminar boundary layer equations were transformed into two ordinary differential equations. To solve these ordinary differential equations for the flow over a flat plate, the Runge-Kutta method of order 5 and 6 was used with a secant method of solving the simultaneous nonlinear equations for the boundary layer conditions. Instead of using the perfect gas assumptions, the properties of air in the temperature range of 100 to 2500 K at M(e) = 8 were used for the calculations. The calculations were carried out for free flight conditions. The real gas effects were significant for the conditions of high freestream Mach numbers, and the boundary layer parameters from the real gas solutions were quite different from the existing formulas and solutions.

Nagamatsu, H. T.↗
NASA NTRS1986

The dynamical evolution of Saturn's E-ring

The dynamical evoluton of fine dust particles ejected from Encladus and subsequently electrically charged within the Saturnian magnetosphere is studied. it is shown that the gyro-phase drift, which is radially outwards due to the strong radial temperature and density gradients in the magnetospheric plasma, is, by far, the fastest transport mechanism of these grains. Maintenance of the E-ring in a steady state throughout the age of the solar system would need a mass loss from Encladus of about 2 parts in 1000.

Hill, J. R.↗
NASA NTRS1987

(2 + 1) resonant enhanced multiphoton ionization of H2 via the E,F 1Sigma(+)g state

In this paper, the results of ab initio calculations of photoelectron angular distributions and vibrational branching ratios for the (2 + 1) resonant enhanced multiphoton ionization (REMPI) of H2 via the E,F 1Sigma(+)g state are reported, and these are compared with the experimental data of Anderson et al. (1984). These results show that the observed non-Franck-Condon behavior is predominantly due to the R dependence of the transition matrix elements, and to a lesser degree to the energy dependence. This work presents the first molecular REMPI study employing a correlated wave function to describe the Rydberg-valence mixing in the resonant intermediate state.

Rudolph, H.↗
NASA NTRS1987

Two-year moored instrument results along 152 deg E

Results from a 2-year (nominal) deployment of a moored array along 152 deg E from 28 deg N to 41 deg N are presented, with emphasis on similarities and differences between settings (approximately year-to-year). Ten moorings and 38 instruments were involved, from the fall of 1980 to 1982. Current-temperature meters spanned the water column from 500- to 4000-m depths, with occasional instruments in the vicinity of 300 m and near the bottom (about 6000 m). Upper level features located in the center of the array near 35-36 deg N were generally stable relative to the axis of the Kuroshio Extension, varying from deployment to deployment with meanders in this flow regime. Some properties of the abyssal (about 4000 m) currents were comparatively more variable, with these changes not connected to meandering of the Kuroshio Extension in an obvious way. The vertical structure and frequency distributions of eddy kinetic energy were similar in shape and to some extent in amplitude from deployment to deployment, especially relative to meanders of the Kuroshio Extension, but translated in the opposite direction.

Schmitz, William J., Jr.↗
NASA NTRS1988

Transport properties for the oxygen system - O2, O, O(+), and e

The transport properties of the oxygen system, O2, O, O(+), and the electron, e, are calculated and their applications are discussed. The possible two-body interactions in the oxygen system are examined and the exponential repulsive potential is used to determine collision integrals for these interactions. Values are presented for the viscosity of the pure gases, the self-diffusion coefficient of the pure gases at 1 atm pressure, the translational thermal conductivity of the pure gases, and the internal thermal conductivity of O2.

Biolsi, Louis↗
NASA NTRS1988

Low latitude thermospheric meridional winds between 250 and 450 km altitude - AE-E satellite data

In situ measurements from the Atmosphere Explorer-E satellite are used to obtain the daily variations of the meridional wind at + or - 18 deg latitude for summer and winter between 1977 and 1979. Data are presented for altitudes around 270, 350, and 440 km. Two features showing significant seasonal variation are found: a late afternoon maximum of the poleward wind occurring in winter at 1800 LT and a nighttime maximum in the equatorward wind with the summer equatorward wind abating earlier and more rapidly than the winter wind. The characteristics of these seasonal variations are discussed in detail.

Herrero, F. A.↗