ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Other Sources  (1,083)
  • LUNAR AND PLANETARY EXPLORATION  (585)
  • FLUID MECHANICS AND HEAT TRANSFER  (498)
  • Inorganic Chemistry
  • 1985-1989  (1,083)
  • 1980-1984
  • 1988  (1,083)
Collection
Source
Keywords
Years
  • 1985-1989  (1,083)
  • 1980-1984
Year
  • 1
    facet.materialart.
    Unknown
    The Lunar Orbital Prospector (1988)
    In:  CASI
    Details
    Publication Date: 2005-07-19
    Description: The Moon is a body rich in natural resources and full of intriguing scientific questions, and it will most certainly play a central role in the growth of near-Earth and deep space ventures of the twenty-first century. The LOP mission is an example of one way to catalog the Moon's natural resources and to answer lunar science questions in parallel. In a realistic planetary exploration program, this mission must compete with other interesting planetary missions and therefore the LOP must be as low cost and adaptable as possible. This flexibility is reflected in the LOP's heavy design emphasis on modularity. The LOP mission can easily be expanded to include new technologies, and additional orbiters could be launched into lunar orbit to provide a constellation of remote-sensing platforms. This design thus projects a broad range of possibilities for continued lunar exploration in the next century.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: USRA, NASA(USRA University Advanced Design Program Fourth Annual Summer Conference; p 145-151
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 2
    facet.materialart.
    Unknown
    Design of a lunar transportation system (1988)
    In:  CASI
    Details
    Publication Date: 2005-07-19
    Description: The establishment of lunar bases is the next logical step in the exploration of space. Permanent lunar bases will support scientific investigation, the industrialization of space, and the development of self-sufficiency on the Moon. Scientific investigation and research and development would lead to applications utilizing lunar material resources. By utilizing these resources, the industrialization of space can become a reality. The above two factors coupled with the development of key and enabling technologies would lead to achievement of self-sufficiency of the lunar base. Attention was focused on specific design(s) to be pursued during subsequent stages in advanced courses. Some of the objectives in the project included: (1) minimizing the transportation of construction material and fuel from earth, or maximizing the use of the lunar material; (2) use of novel materials and light weight structures; (3) use of new manufacturing methods and technology such as magnetically levitated, or superconducting materials; and (4) innovative concepts of effectively utilizing the exotic lunar conditions, i.e. high thermal gradients, lack of atmosphere, zero wind forces, and lower gravity, etc.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: USRA, NASA(USRA University Advanced Design Program Fourth Annual Summer Conference; p 89-92
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 3
    facet.materialart.
    Unknown
    Measurements of reflectance spectra of ion-bombarded ice and application to surfaces in the outer solar system (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The first results of laboratory measurements of the wavelength dependence of the alternation of the visible reflectance of H2O ice irradiated by keV ions are presented. When the implanted species is chemically neutral, absorption is slightly enhanced below 0.55 micron. For an incident species containing sulfur, a strong absorption feature is produced at 0.4 micron, probably corresponding to S3. This occurs at too large a wavelength to account for the absorption feature observed at Europa by Voyager and therefore casts doubt on the recent interpretation of the reflectance data of Europa.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Nature (ISSN 0028-0836); 333; 240
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 4
    facet.materialart.
    Unknown
    A direct interaction approximation treatment of turbulence in a compressible fluid. I - Formalism (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The direct interaction approximation is used to treat turbulence in a compressible medium with constant mean gradients. The set of coupled nonlinear integrodifferential equations is derived that is satisfied by the transverse and longitudinal energy spectral functions, Q(T) and Q(L) and by the transverse and longitudinal response functions, G(T) and G(L). Finally, expressions for the average of the product of pairs of physically relevant fluctuating quantities (velocity, temperature, density) are derived in terms of Q(T) and Q(L).
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Physics of Fluids (ISSN 0031-9171); 31; 1034-105
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 5
    facet.materialart.
    Unknown
    Surficial textures of the Galilean satellites (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The observations of the Galilean satellites of Jupiter obtained with the IUE have been analyzed as a function of solar phase angle. By fitting the measurements to a shadowing model, comparative descriptions of the microtextures of the optically active portion of the surfaces of the satellites are derived. Important differences among the satellites and between leading and trailing hemispheres of individual satellites result from the different processes of meteoritic bombardment, magnetospheric interaction, and geological resurfacing that operate in the Jovian system. Io and Callisto have the most tenuous upper regoliths, whereas the surface of the leading side of Europa is the most compact.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Nature (ISSN 0028-0836); 333; 148-151
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 6
    facet.materialart.
    Unknown
    Thermal structure of the ionosphere of Mars - Simulations with one- and two-dimensional models (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Heat flux saturation effects are included in the present one- and two-dimensional models of the Martian upper ionosphere's thermal structure. The inclusion of small upper boundary and volume heat sources is found to yield satisfactory simulations of the dayside ion temperature observation results obtained by Viking 1's retarding potential analyzers. It is noted that the plasma flow-transport of heat from the dayside to the nightside makes no contribution to the ion and electron temperatures that have been calculated for the nightside.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus (ISSN 0019-1035); 74; 357-364
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 7
    facet.materialart.
    Unknown
    Deformational models of rifting and folding on Venus (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Features of presumed tectonic origin on Venus are reviewed, and lithospheric strength envelopes are derived based on laboratory measurements of the deformational properties of crustal and subcrustal rocks, extrapolated to conditions appropriate to Venus. Models for rifting and folding are developed that use this lithospheric structure and take into account both brittle and ductile yielding as well as finite elastic strength. For both rifting and folding, structures with characteristic widths and spacings are predicted whose size depends on the thickness of the lithosphere, density contrast, and elastic properties of the layer. Finally, the model predictions are compared with the widths and spacings of observed tectonic features, and it is concluded that they are consistent with a relatively strong mantle layer separated from a thin brittle surface layer by a ductile lower crust. These results allow constraints to be placed on the crustal thickness and thermal gradient on Venus.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research (ISSN 0148-0227); 93; 4759-477
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 8
    facet.materialart.
    Unknown
    Generalized energy and potential enstrophy conserving finite difference schemes for the shallow water equations (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The conditions under which finite difference schemes for the shallow water equations can conserve both total energy and potential enstrophy are considered. A method of deriving such schemes using operator formalism is developed. Several such schemes are derived for the A-, B- and C-grids. The derived schemes include second-order schemes and pseudo-fourth-order schemes. The simplest B-grid pseudo-fourth-order schemes are presented.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Monthly Weather Review (ISSN 0027-0644); 116; 650-662
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 9
    facet.materialart.
    Unknown
    Evolution of a steam atmosphere during earth's accretion (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The evolution of an impact-generated steam atmosphere around an accreting earth is presently modeled under the assumption of Safronov (1978) accretion, in a scheme that encompasses the degassing of planetesimals on impact, thermal blanketing by the steam atmosphere, surface-to-interior water exchange, the shock heating and convective cooling of the earth's interior, and hydrogen escape due both to solar EUV-powered planetary wind and impact erosion. The model yields four distinct classes of impact-generated atmospheres: the first, on which emphasis is placed, has as its salient feature a molten surface that is maintained by the opacity of a massive water vapor atmosphere; the second occurs when the EUV-limited escape exceeds the impact degassing rate, while the third is dominated by impact erosion and the fourth is characterized by an atmosphere more massive than any thus far encountered.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus (ISSN 0019-1035); 74; 62-97
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 10
    facet.materialart.
    Unknown
    On the origin of Venus' atmosphere - Possible contributions from simple component mixtures and fractionated solar wind (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: It is suggested that while an origin of the volatiles of the Venus atmosphere as a single, fractionated component derivable from the solar wind can account for Ar, Kr, and Xe relative abundances, it does so only with an excess of C, and perhaps of N. A similarity is noted in relative abundances between Venus volatiles and fractionated solar wind gases in the lunar regolith which implies that such a lunar-type component is a major contributor to Venus' volatiles. A variety of Venus atmosphere models is considered; these fail to explain the low Ne/Ar ratio on Venus.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus (ISSN 0019-1035); 74; 3-20
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 11
    facet.materialart.
    Unknown
    Source of the Australasian tektite strewn field - A possible off-shore impact site (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Although there is a preponderance of evidence that tektites were formed by asteroid impacts on the earth, no source crater has been found for the largest and youngest of the strewn fields - the Austalasian strewn field. A combined Seasat/Geos 3 altimeter data set of sea surface heights in the northern portion of the Australasian strewn field has been examined for negative gravity anomalies on the continental shelf and slope which might be related to the source crater for these tektites. A large negative anomaly called the Qui Nhon Slope Anomaly is a sea surface depression of approximately 1.5 meters over an area of 100 km diameter. It corresponds to a gravity anomaly of about -50 mgal. It is proposed that this anomaly may be due to the impact structure that produced the Australasian strewn field.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Geophysical Research Letters (ISSN 0094-8276); 15; 357-360
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 12
    facet.materialart.
    Unknown
    The solar wind control of Jupiter's broad-band kilometric radio emission (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Observations of the solar wind close to Jupiter are compared with the broad-band kilometric radio emission (bKOM), using data recorded by Voyager 1 and Voyager 2 during 1979. The lower bKOM frequencies, less than about 300 kHz, are found to correlate with the solar wind density and pressure and with the interplanetary magnetic field (IMF) magnitude during periods when there is a well-defined magnetic sector structure. The results suggest that lower frequency bKOM events are most likely to occur after a sector boundary has passed Jupiter during the period when the solar wind density and the IMF magnitude are increasing towards the sector center. The average bKOM energy per Jovian rotation tends to have lower values soon after the sector center has passed. Higher-frequency/higher-energy bKOM emission may be contaminated by hectometric emission (HOM) and differently correlated with solar activity. The solar wind control may also be obscured by some stronger control. It is suggested that electron density fluctuations in the Io torus, where the source is believed to be located, may be responsible for variations in the beaming and hence variations in the observed emission.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Astronomy and Astrophysics (ISSN 0004-6361); 192; 1-2,; 354-359
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 13
    facet.materialart.
    Unknown
    Renormalization-group theory for the eddy viscosity in subgrid modeling (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Renormalization-group theory is applied to incompressible three-dimensional Navier-Stokes turbulence so as to eliminate unresolvable small scales. The renormalized Navier-Stokes equation now includes a triple nonlinearity with the eddy viscosity exhibiting a mild cusp behavior, in qualitative agreement with the test-field model results of Kraichnan. For the cusp behavior to arise, not only is the triple nonlinearity necessary but the effects of pressure must be incorporated in the triple term. The renormalized eddy viscosity will not exhibit a cusp behavior if it is assumed that a spectral gap exists between the large and small scales.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Physical Review A - General Physics, 3rd Series (ISSN 0556-2791); 37; 2590-259
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 14
    facet.materialart.
    Unknown
    The centring dynamics of a thin liquid shell in capillary oscillations (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The physical mechanism governing the centring of a hollow liquid shell in capillary oscillations, which has been observed in experiments, is investigated theoretically. First, the shell is assumed to be inviscid and to have a thickness that is much less than its spherical radius. A system of one-dimensional nonlinear equations of motion is derived using a thin-sheet model. From a numerical study the nonlinear effects of the wave are found to cause the core to oscillate slowly relative to the shell while the centre of mass of the whole system remains stationary. The effects of small viscosity are then considered in an approximation. Finally the strength of the centring mechanism is compared with that of the decentring effect due to buoyancy. The findings are consistent with the limited experimental information available.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Fluid Mechanics (ISSN 0022-1120); 188; 411-435
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 15
    facet.materialart.
    Unknown
    Developing fluid flow in a curved duct of square cross-section and its fully developed dual solutions (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Developing fluid flow in a curved duct of square cross-section is studied numerically by a factored ADI finite-difference method on a staggered grid. A central-difference scheme with primitive variables is used inside the computational domain to reduce numerical diffusion. Two Reynolds numbers, 574 and 790, based upon a bulk velocity and hydraulic diameter are chosen for curvature ratios of 1/6.45 and 1/2.3, respectively. It is found that the secondary flow is far more complicated than expected, with the appearance of at least two pairs of vortices. Main-flow separation is also observed for the higher curvature ratio. Furthermore, it is observed that the flow develops into two quite different states downstream, depending upon the inlet conditions. Solutions of the fully developed Navier-Stokes equations is shown to be not unique beyond a certain critical Reynolds number. Developing flow seems to evolve into the fully developed state along a particular branch into which the fully developed solution bifurcates.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Fluid Mechanics (ISSN 0022-1120); 188; 337-361
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 16
    facet.materialart.
    Unknown
    Large impact basins and the mega-impact origin for the crustal dichotomy on Mars (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The hypothesis that the crustal dichotomy on Mars is due to a single giant (mega) impact early in Martian history is tested by determining the number of 'missing' basins, the difference between the observed number of large impact basins on Mars and the number expected from a 1/D-squared distribution. If the Borealis Basin was the largest member of a 1/D-squared impact population, a large number of 'missing' basins is expected which is too large to be hidden by the younger surface units. If Chryse is the largest member of a 1/D-squared impact population, the more modest number of 'missing' basins could be confined to areas of Mars that have been resurfaced or reworked by subsequent geologic processes.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Geophysical Research Letters (ISSN 0094-8276); 15; 229-232
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 17
    facet.materialart.
    Unknown
    Multiphase flow in porous media (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: A development history and current status evaluation are presented for the theory of permeability and percolation. The microscale phenomena treated in this field have proven difficult to analyze due both to their tortuous geometry and the influence of capilarity. Capilary effects may be not only important but predominant, and are differentiated into those at the fluid-fluid interface, and those involving the existence of a contact line between the solid substrate and this interface. Percolation theory has been borrowed from physics and adapted to the two-phase engineering context.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 18
    facet.materialart.
    Unknown
    Thermal emission from Saturn's rings at 380 microns (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Two different techniques have been used to derive the Saturn disk's ring brightness temperatures from 380-micron observations: (1) comparisons of these wide-beam observation disk-ring system results with those obtained for an earlier epoch, when the rings were edge-on, then differencing the two measurements to obtain a value for the rings' contribution; and (2) ring contribution resolution during scanning along the disk-ring plane, to yield a B-ring brightness temperature of 39 + or - 8 K at 380 microns. The results obtained indicate a gradual decrease of observed ring brightness temperature from the IR to the radio wavelength range.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus (ISSN 0019-1035); 574-583
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 19
    facet.materialart.
    Unknown
    Condensation heat transfer in a microgravity environment (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Thermophysics and Heat Transfer (ISSN 0887-8722); 2; 82-84
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 20
    facet.materialart.
    Unknown
    Flow-induced morphological instabilities - The rotating disc (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The morphological stability of a rotating and solidifying disk is investigated under the assumption that delta, the thickness of the viscous boundary layer, is much larger than delta(c), the thickness of the solute boundary layer. It is found that axisymmetric disturbances with wavelengths comparable to delta respond to nonparallel flow effects and have stability characteristics quite different from disturbances in a parallel flow. These long waves are unstable because of the nonparallel flow and would decay without it. This analysis thus identifies a new mechanism of morphological change induced by flow.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Crystal Growth (ISSN 0022-0248); 87; 4, Ma; 385-396
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 21
    facet.materialart.
    Unknown
    Superposed ridges of the Hesperia Planum area on Mars (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Mare ridges of the Hesperia Planum area form linear, reticular and circular structures. The main factors effective in mare ridge formation have been: (1) a large areal, or maybe even global, shortening and compression, (2) major crustal tectonics, and (3) the moderation of tectonic movements by the megaregolith discontinuity layer(s) between surface lavas and the bedrock leaving the compressional thrust to dominate over other fault movements in surface tectonics.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Earth, Moon, and Planets (ISSN 0167-9295); 40; 71-99
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 22
    facet.materialart.
    Unknown
    Analysis of Pioneer Venus Orbiter ultraviolet spectrometer Lyman alpha data from near the subsolar region (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Pioneer Venus Orbiter ultraviolet spectrometer data from 20 orbits which span 3 years have been analyzed to determine the atomic hydrogen number density and vertical flux at the exobase as a function of solar zenith angle, F(10.7) index, and spacecraft latitude. From 1979 through 1981, the exobase number density n(c) and flux phi(c) are remarkably constant at n(c) = 6.0 + or - 1.5 x 10 to the 4th/cu cm and phi(e) = 7.5 + or - 1.5 x 10 to the 7th/sq cm per s in the subsolar region. The integrated vertical column density above 110 km is 3.6 + or - 1 x 10 to the 13th/sq cm. An empirical relationship is determined between the line center solar flux at H Lyman alpha, piF(0), and the F(10.7) index.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research (ISSN 0148-0227); 93; 1766-177
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 23
    facet.materialart.
    Unknown
    Voyager at Uranus (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The findings made in the Voyager flyby past Uranus are reviewed. The spacecraft is described, and the preparations for the Uranus encounter are recalled. The encounter characteristics are presented, and the characteristics of the Uranian atmosphere and interior, magnetic field, rings, and satellites are discussed.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: (ISSN 0007-084X); 41; 49-62
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 24
    facet.materialart.
    Unknown
    On the receptivity of free shear layers to two-dimensional external excitation (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: In this paper, the receptivity of a typical free shear layer to pulse-type and periodic excitation is studied. This is done by solving the initial-value problem completely and studing its long-time behavior. This leads to a wave packet for the pulse. By the superposition of many wave packets, a spatial instability mode when the flow is convectively unstable is generated. This establishes a general and simple relationship between the receptivities for pulse-type and sinusoidal excitations. It is found that a shear layer is very receptive to high-frequency disturbances that are generated near the centerline of the layer.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Fluid Mechanics (ISSN 0022-1120); 187; 155-177
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 25
    facet.materialart.
    Unknown
    Direct simulation of a turbulent boundary layer up to R sub theta = 1410 (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The turbulent boundary layer on a flat plate, with zero pressure gradient, is simulated numerically at four stations between R sub theta = 225 and R sub theta = 1410. The three-dimensional time-dependent Navier-Stokes equations are solved using a spectral method with up to about 10 to the 7th grid points. Periodic spanwise and streamwise conditions are applied, and a multiple-scale procedure is applied to approximate the slow streamwise growth of the boundary layer. The flow is studied, primarily, from a statistical point of view. The solutions are compared with experimental results. The scaling of the mean and turbulent quantities with Reynolds number is compared with accepted laws, and the significant deviations are documented. The turbulence at the highest Reynolds number is studied in detail. The spectra are compared with various theoretical models. Reynolds-stress budget data are provided for turbulence-model testing.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Fluid Mechanics (ISSN 0022-1120); 187; 61-98
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 26
    facet.materialart.
    Unknown
    A direct interaction approximation treatment of high Rayleigh number convective turbulence and comparison with experiment (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: A method is proposed for treating steady-state, thermally driven convection using the full direct interaction approximation to treat the nonlinear energy transfer and a prescribed instability function to model the eenrgy input. The instability function used is the growth rate of the mechanism generating the turbulence. This methodology can be easily generalized and applied to other driving mechanisms. The 1/3 power law form of the N vs. R relation for water is duplicated here and the coefficient is computed, using a two-point closure, to be less than about 0.08.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Physics of Fluids (ISSN 0031-9171); 31; 256-262
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 27
    facet.materialart.
    Unknown
    Neptune radio emission - Predictions based on planetary scaling laws (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: In this paper a prediction is advanced concerning Neptune's low-frequency radio emission based on the radiometric Bode's law for radio planets in combination with the magnetostrophic scaling law for magnetized planets. The total emitted radio power is predicted to be about 1.6 x 10 to the 7th W, very nearly the same as that predicted and observed for Uranus. Possible emission spectral shapes, based on Saturn and earth-like models, are shown. Using these models, the radio emission frequency range is predicted to extend from approximately 100 to just over 1000 kHz, with a spectral peak between 350 and 500 kHz. If radiation is beamed approximately in the sunward direction, Neptune should be detectable by the planetary radio astronomy experiment onboard the Voyager spacecraft sometime between 45 and 90 days before closest approach. This detection is likely to represent the first direct evidence of a Neptune magnetic field. Possible implications for Neptune's magnetosphere with regard to the time of first detection are discussed.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Geophysical Research Letters (ISSN 0094-8276); 15; 114-1117
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 28
    facet.materialart.
    Unknown
    High resolution images of Venus from ground-based radar (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The Goldstone Deep Space Station ground-based synthetic aperture radar system has been used to obtain radar images of Venus with resolutions of close to 1.3 km. Observations were made at 12.5 cm wavelength using circular polarization. From 12 days of observations during the 1986 inferior conjunction, three images have been selected for initial processing. The images show remarkable surface features including craters, ridges, and regions of high Fresnel reflectivity in the plains region.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Geophysical Research Letters (ISSN 0094-8276); 15; 577-580
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 29
    facet.materialart.
    Unknown
    Velocity spectra in the irrotational flow outside a turbulent shear layer (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The relationship between the spectra of the three normal stresses near a turbulent shear layer is derived from the constraint of irrotationality. The relationship implies that the common practice of determining time scales of the turbulence from spectra in the near field is not valid. This implication is reinforced by a discussion of the scaling of irrotational spectra that follows from the formulation of Phillips (1975).
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Physics of Fluids (ISSN 0031-9171); 31; 1807
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 30
    facet.materialart.
    Unknown
    Ejection mechanisms in the sublayer of a turbulent channel (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The structure of the vorticity field in the viscous wall layer of a turbulent channel is studied by examining the results of a fully resolved direct numerical simulation. It is shown that this region is dominated by intense three-dimensional shear layers in which the dominant vorticity component is spanwise. The advection and reproduction processes of these structures are examined and shown to be consistent with the classical generation mechanism for two-dimensional Tollmien-Schlichting waves. This process is fundamentally different from the usually accepted mechanism involving hairpin vortices.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Physics of Fluids (ISSN 0031-9171); 31; 1311-131
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 31
    facet.materialart.
    Unknown
    High-temperature shock formation of N2 and organics on primordial Titan (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Theoretical models suggest that the initial form of nitrogen in Titan's atmosphere may have been NH3. The possible importance of strong shocks produced during high-velocity impacts accompanying the late stages of accretion are investigated as a method for converting NH3 to N2, of which Titan's atmosphere is now primarily composed. The focused beam of a high-power laser is used to simulate the effects of an impact in Titan's atmosphere. For mixtures of 10, 50, and 90 percent NH3, yields of 0.25, 1, and 6 x 20 to the 17th molecules of N2 per joule, respectively, were obtained. It is also found that the yield of HCN is comparable to that for N2. Several other hydrocarbons are produced, many with yields in excess of theoretical high-temperature-equilibrium models. The above yields, when combined with models of the satellite's accretion, result in a total N2 production comparable to that present in TItan's atmosphere and putative ocean.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Nature (ISSN 0028-0836); 332; 520-522
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 32
    facet.materialart.
    Unknown
    Charged particle depletion surrounding Saturn's F ring - Evidence for a moonlet belt? (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: An improved model of the Saturn magnetosphere and of the locations of known moons and rings is invoked in the present reconsideration of Pioneer 11 observations of five abrupt depletions in the flux of trapped magnetospheric electrons within a 2000-km-wide band around the F ring. It is inferred that the observed depletions of charged particles are caused by clumps of material with low optical depth; it is further hypothesized that these clumps are composed of regolith ejecta, are generated by collisions occurring within a belt of unseen, moonlet-scale (or smaller) objects occupying the entire radial region between Pandora and Prometheus. Attention is given to a self-consistent scenario in which these debris clouds are created, longitudinally spread, swept up onto belt object surfaces, and then thrown off by a subsequent collision.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus (ISSN 0019-1035); 74; 284-324
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 33
    facet.materialart.
    Unknown
    Planetographic clustering of low-altitude impulsive electric signals in the night ionosphere of Venus (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: This paper presents maps of the locations of electromagnetic signals, presumably caused by lightning, which were observed at 730 Hz during the first three nighttime observing seasons of Pioneer Venus Orbiter when the spacecraft reached altitudes low enough to detect the signals. The maps show that there are specific 'active regions' of enhanced signal occurrence, and that at least some of these active regions appear to remain fixed in planetographic coordinates from year to year.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Nature (ISSN 0028-0836); 331; 591-594
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 34
    facet.materialart.
    Unknown
    'Domestic' origin of opaque assemblages in refractory inclusions in meteorites (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Experimental studies indicate that opaque assemblages rich in refractory siderophile elements were formed within host calcium- and aluminum-rich inclusions (CAIs) by exsolution, oxidation and sulphidization of homogeneous alloys, rather than by aggregation of materials in the solar nebula before the formation of CAIs. These opaque assemblages are thus not the oldest known solid materials, as was once thought, and they do not constrain processes in the early solar nebula before CAI formation. Instead, the assemblages record the changing oxygen fugacity experienced by CAIs during slow cooling in nebular and/or planetary environments.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Nature (ISSN 0028-0836); 331; 405-409
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 35
    facet.materialart.
    Unknown
    A finite element computation of turbulent boundary layer flows with an algebraic stress turbulence model (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: An algebraic stress turbulence model and a computational procedure for turbulent boundary layer flows which is based on the semidiscrete Galerkin FEM are discussed. In the algebraic stress turbulence model, the eddy viscosity expression is obtained from the Reynolds stress turbulence model, and the turbulent kinetic energy dissipation rate equation is improved by including a production range time scale. Good agreement with experimental data is found for the examples of a fully developed channel flow, a fully developed pipe flow, a flat plate boundary layer flow, a plane jet exhausting into a moving stream, a circular jet exhausting into a moving stream, and a wall jet flow.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Computer Methods in Applied Mechanics and Engineering (ISSN 0045-7825); 66; 45-63
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 36
    facet.materialart.
    Unknown
    Free-streamline analysis of deformation and dislodging by wind force of drops on a surface (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Free-streamline theory is used to analyze the deformation and dislodging by wind pressure of drops of liquid adhered by surface tension to a solid surface. The critical Weber number for droplets to be dislodged is determined as a function of advancing and receding contact angle. Graphical results for drop shape are in good agreement with observation.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Physics of Fluids (ISSN 0031-9171); 31; 43-48
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 37
    facet.materialart.
    Unknown
    Are there carbonate deposits in the Valles Marineris, Mars? (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The precipitation of 30 mbar of Martian atmosphere CO2 as carbonates in lakes is suggested to be the source of thick sequences of layered deposits found in the Valles Marineris. Support is adduced for this scenario from processes occurring in the perennially frozen dry valley lakes of Antarctica, where the lake water is supersaturated with atmospheric gases. Atmospheric CO2 would have accumulated in such Martian lakes as temperatures fell, and the presence of an insulating ice cover would have allowed liquid water to exist.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus (ISSN 0019-1035); 73; 142-148
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 38
    facet.materialart.
    Unknown
    Interactions of planetesimals with protoplanetary atmospheres (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The 'core instability' mechanism presently postulated for the interaction of planetesimals with the envelopes of growing giant planets involves core growth through the accretion of solid bodies in the solar nebula; the core thereby becomes more effective in the gravitational attraction of gas from the surrounding nebula into an envelope, until a runaway accretion stage is reached. Two-body trajectory curves of planetesimals through this envelope are computed which demonstrate the depth of penetration and the cross-sections for capture of icy and rocky planetesimals.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus (ISSN 0019-1035); 73; 163-179
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 39
    facet.materialart.
    Unknown
    How climate evolved on the terrestrial planets (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: It is argued that the difference in the climates of Venus, earth, and Mars is due largely to differences in their ability to cycle CO2 between the crust and atmosphere. It is suggested that the earth has always had a moderate climate primarily because its cycling mechanism increases the amount of CO2 in the atmosphere when the surface of the planet cools and reduces the amount when the ground temperature rises. Mars is now frozen because it has lost the ability to cycle the gas back into its atmosphere, and Venus is a hothouse because it has no way of removing CO2 from its atmosphere.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Scientific American (ISSN 0036-8733); 258; 90-97
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 40
    facet.materialart.
    Unknown
    The tectonics of Mercury (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The probable tectonic history of Mercury and the relative sequence of events are discussed on the basis of data collected by the Mariner-10 spacecraft. Results indicate that Mercury's tectonic activity was confined to its early history; its endogenic activity was principally due to a small change in the shape of its lithosphere, caused by tidal despinning, and a small change in area caused by shrinkage due to cooling. Exogenic processes, in particular the impact activity, have produced more abundant tectonic features. Many features associated with the Caloris basin are due to loading of Mercury's thick lithosphere by extrusive lavas or subsidence due to magma withdrawal. It is emphasized that tectonic features observed on Mercury yield insight into the earliest tectonic events on planets like Mars and, perhaps, the earth, where subsequent events obscured or erased the most ancient tectonic records.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 41
    facet.materialart.
    Unknown
    Surface composition of Mercury from reflectance spectrophotometry (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The controversies surrounding the existing spectra of Mercury are discussed together with the various implications for interpretations of Mercury's surface composition. Special attention is given to the basic procedure used for reducing reflectance spectrophotometry data, the factors that must be accounted for in the reduction of these data, and the methodology for defining the portion of the surface contributing the greatest amount of light to an individual spectrum. The application of these methodologies to Mercury's spectra is presented.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 42
    facet.materialart.
    Unknown
    Meteorite regolithic breccias (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: In addition to endogenic processes such as heating and aqueous activity, meteorite parent bodies were subjected also to exogenic processing brought about by the impact of the other solar-system objects. Such impacts can produce a variety of effects, ranging from shock metamorphism of individual mineral grains to production of breccias; i.e., rocks consisting of mixtures of disparate lithic units. The present paper reviews recent studies of such breccias, which have generated significant information about the accretional growth of parent bodies, as well as their evolution, composition, stratigraphy, and geological processing.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 43
    facet.materialart.
    Unknown
    Considerations on the moving contact-line singularity, with application to frictional drag on a slender drop (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: It has previously been shown that the no-slip boundary conditions leads to a singularity at a moving contact line and that this presumes some form of slip. Present considerations on the energetics of slip due to shear stress lead to a yield stress boundary condition. A model for the distortion of the liquid state near solid boundaries gives a physical basis for this boundary condition. The yield stress condition is illustrated by an analysis of a slender drop rolling down an incline. That analysis provides a formula for the frictional drag resisting the drop movement. With the present boundary condition, the length of the slip region becomes a property of the fluid flow.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Fluid Mechanics (ISSN 0022-1120); 197; 157-169
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 44
    facet.materialart.
    Unknown
    Extended sodium exosphere of the moon (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Sodium emission has been observed up to 1200 km above the subsolar limb of the moon at third quarter. The intensity of the emission is far in excess of that predicted from the scale height and surface density derived previously from measurements of sodium emission at low altitudes above the lunar surface. This can be explained by assuming that there are both 'hot' and 'cold' components of the lunar sodium exosphere.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Geophysical Research Letters (ISSN 0094-8276); 15; 1515-151
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 45
    facet.materialart.
    Unknown
    Io - Evidence for silicate volcanism in 1986 (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Infrared observations of Io during the 1986 apparition of Jupiter indicate that a large eruptive event occurred on the leading side of Io on August 7, 1986, UT. Measurements made at 4.8, 8.7, and 20 micrometers suggest that the source of the event was about 15 kilometers in radius with a model temperature of about 900 K. These measurements indicate that high-temperature volcanic activity on the leading side of Io may be more frequent than previously thought. The inferred temperature is significantly above the boiling point of sulfur in a vacuum (715 K) and thus constitutes strong evidence for active silicate volcanism on the surface of Io.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science (ISSN 0036-8075); 242; 1280-128
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 46
    facet.materialart.
    Unknown
    Lower-upper Symmetric-Gauss-Seidel method for the Euler and Navier-Stokes equations (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA Journal (ISSN 0001-1452); 26; 1025
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 47
    facet.materialart.
    Unknown
    Numerical study of the interactions between droplets at intermediate Reynolds numbers (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Propulsion and Power (ISSN 0748-4658); 4; 481-489
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 48
    facet.materialart.
    Unknown
    Stratospheric composition measurements of earth and Titan using high-resolution tunable diode laser spectroscopy (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Field and laboratory measurements of species of atmospheric interest made as part of the JPL diode laser spectroscopy program are presented. Stratospheric measurements of NO2, NO, CO2, and H2O made in November 1985 using the BLISS instrument are reported, together with recent laboratory measurements of spectral line parameters of HNO3 and HO2NO2. In addition, a novel diode laser instrument concept for the in situ sensing of Titan's atmosphere is described for the Saturn Orbiter/Titan Probe (SOTP) Cassini Mission.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Quantitative Spectroscopy and Radiative Transfer (ISSN 0022-4073); 40; 239-248
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 49
    facet.materialart.
    Unknown
    Spectra of van der Waals complexes (dimers) with applications to planetary atmospheres (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Spectral features observed in the atmosphere of Titan by the Voyager IR experiment have been attributed to weakly bound complexes of N2 and H2, dominant and minor constituents, respectively. The abundance of H2-N2 dimers there was computed. Current calculations include quantitative spectral line positions and intensities for N2-Ar and CO2-CO2 relating to Titan and Earth, and to Mars and Venus, respectively. This work suggests applications to spectra of planetary atmospheres obtained in spacecraft missions.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Quantitative Spectroscopy and Radiative Transfer (ISSN 0022-4073); 40; 177-184
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 50
    facet.materialart.
    Unknown
    Unsteady solution of incompressible Navier-Stokes equations (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The numerical scheme used by the present time-accurate FEM numerical method for incompressible Navier-Stokes equations, using primitive variables as the unknowns, is a Crank-Nicholson implicit treatment of all equation terms with central differencing for space derivatives. The introduction of a continuous auxilliary system in pseudo-time, with artificial compressibility, yields the incompressible solution at the advanced time level; time-accurate solutions are thereby obtained for two-dimensional fluid flows in a square cavity, in the cases of both an impulsively starting lid and an oscillating lid.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Computational Physics (ISSN 0021-9991); 79; 113-134
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 51
    facet.materialart.
    Unknown
    Zonally symmetric response to atmospheric tidal forcing in the dusty Martian atmosphere (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The paper presents a steady state, zonally symmetric response of an atmospheric circulation to the combined effects of the very large zonal-mean diabatic heating and thermotidal forcing thought to exist in the dusty Martian atmosphere during one of its episodic global dust storms. The zonal-mean components of the tidal flux-convergences of momentum and heat are computed using an existing classical atmospheric tidal model constrained by the surface pressure observations at the two Viking Lander sites on Mars. A nearly inviscid two-dimensional model is used to compute the zonally symmetric response to the computed tidal flux-convergences and to the zonal-mean heating of the airborne dust. The results are compared with data from the Viking missions.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of the Atmospheric Sciences (ISSN 0022-4928); 45; 2469-248
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 52
    facet.materialart.
    Unknown
    Lightning production of hydrocarbons and HCN on Titan - Laboratory measurements (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Experimental measurements have been obtained for the chemical yields of hydrogen cyanide, acetylene, ethylene, ethane, and propane from simulated lightning discharges, in order to ascertain whether lightning in the troposphere of Titan may be contributing to the hydrocarbon inventory. A comparison of these results with those obtained on the basis of thermodynamic equilibrium considerations shows substantial discrepancies and implies that thermodynamic equilibrium theories are inadequate. The production of ethylene by lightning and its subsequent stratospheric diffusion nevertheless appears to be one reasonable mechanism.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus (ISSN 0019-1035); 76; 125-134
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 53
    facet.materialart.
    Unknown
    Measurements of the free-stream fluctuations above a turbulent boundary layer (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The paper describes an investigation of the velocity fluctuations in the free stream above an incompressible turbulent boundary layer developing at constant pressure. Measurements were performed in a wind tunnel with an rms level of axial velocity fluctuations of about 0.2 percent. The possibility of assessing the contributions to the rms level of the velocity fluctuations without using the high-pass filtering technique is demonstrated.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Physics of Fluids (ISSN 0031-9171); 31; 2834-284
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 54
    facet.materialart.
    Unknown
    Mars - Satellite and ring search from Viking (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Viking Orbiter 1 imaging data were used in a search for possible satellites and rings of Mars in 1980, giving attention to a region within the Phobos orbit and + or - 350 km about the Martian equatorial plane. After picture processing, no images other than stars and Phobos itself were found to be a few brightnesses (or more) above their surrounding, as would be expected in the case of a point-spread, 'smeared' image of either satellites or rings. There is therefore no evidence of any such phenomenon in the 78 pictures studied.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus (ISSN 0019-1035); 76; 160-162
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 55
    facet.materialart.
    Unknown
    Pressure-induced absorption coefficients for radiative transfer calculations in Titan's atmosphere (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The semiempirical theory of Birnbaum and Cohen (1976) is used to calculate the FIR pressure-induced absorption (PIA) spectra of N2, CH4, N2 + Ar, N2 + CH4, and N2 + H2 under conditions like those in the Titan troposphere. The results are presented graphically and compared with published data from laboratory measurements of PIA in the same gases and mixtures (Dagg et al., 1986; Dore et al., 1986). Good agreement is obtained, with only a slight underestimation of PIA at 300-400/cm in the case of CH4. The absorption coefficients are presented in tables, and it is suggested that the present findings are of value for evaluating the effects of tropospheric clouds on the Titan FIR spectrum and studying the greenhouse effect near the Titan surface.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus (ISSN 0019-1035); 75; 245-254
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 56
    facet.materialart.
    Unknown
    Methane rain on Titan (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The atmosphere of Titan is characterized by means of model computations based on Voyager IRIS IR spectra and published data from laboratory determinations of absorption coefficients and cloud refractive indices. The results are presented in tables and graphs, and it is pointed out that the presence of Ar is not required in the model. Particular attention is given to the role of CH4, which is found to form patchy clouds (with particle radii of 50 microns or greater and visible/IR optical depths of 2-5) at altitudes up to about 30 km. The mechanisms by which such rain-sized particles could form are discussed, and it is suggested that the observed 500-600/cm spectrum is affected much less by the CH4 clouds than by H2 or variations in the temperature of the high-altitude haze.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus (ISSN 0019-1035); 75; 255-284
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 57
    facet.materialart.
    Unknown
    Model consistency in large eddy simulation of turbulent channel flows (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Combinations of filters and subgrid scale stress models for large eddy simulation of the Navier-Stokes equations are examined by a priori tests and numerical simulations. The structure of the subgrid scales is found to depend strongly on the type of filter used, and consistency between model and filter is essential to ensure accurate results. The implementation of consistent combinations of filter and model gives more accurate turbulence statistics than those obtained in previous investigations in which the models were chosen independently from the filter. Results and limitations of the a priori test are discussed. The effect of grid refinement is also examined.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Physics of Fluids (ISSN 0031-9171); 31; 1884-189
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 58
    facet.materialart.
    Unknown
    Structure of rough-wall turbulent boundary layers (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Recent experiments have shown that, in rough-wall turbulent boundary layers, drag varies systematically with the spanwise aspect ratio lambda(z) (span/height) of roughness elements. In this paper, the effect of lambda(z) on turbulence structure has been examined. Based on lambda(z), the roughness in a transversely grooved surface with lambda(z) much greater than 1 is the opposite extreme of model plant canopies with lambda(z) much less than 1, studied in wind tunnels, whereas sandgrain is an intermediate type. Second-, third-, and fourth-order turbulence moments have been measured in turbulent boundary layers over transversely grooved and smooth surfaces and compared with available turbulence structure measurements over other types of surfaces. The near-wall turbulence structure is found to vary with lambda(z). The instantaneous motions involved in the flux of shear stress near the wall in smooth and transversely grooved surfaces are opposite in sign to those in three-dimensional roughness. The former is explained in terms of hairpin vortices alone, while the latter group is modeled to have an additional vortex (the so-called necklace vortex which straddles a three-dimensional roughness element near its base).
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Physics of Fluids (ISSN 0031-9171); 31; 1877-188
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 59
    facet.materialart.
    Unknown
    Stability of swirling gas flows (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The stability of inviscid swirling gas flows to small nonaxisymmetric perturbations is considered. For small Brunt-Vaisala frequencies, the problem reduces to the classical Sturm-Liouville form and the oscillation theorem can be applied. The resulting necessary and sufficient stability condition is compared to various criteria in the literature and a limited numerical study of isothermal rigidly rotating Poiseuille flow. For given azimuthal and axial wavenumbers, it is found numerically that the higher inertial modes become unstable for successively lower Rossby numbers and that this sequence of critical values approaches the theoretical value from above.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Physics of Fluids (ISSN 0031-9171); 31; 1872-187
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 60
    facet.materialart.
    Unknown
    Weak solutions of the three-dimensional vorticity equation with vortex singularities (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The extension of the concept of vortex singularities, developed by Saffman and Meiron (1986) for the case of two-dimensional point vortices in an incompressible vortical flow, to the three-dimensional case of vortex sticks (vortons) is investigated analytically. The derivation of the governing equations is explained, and it is demonstrated that the formulation obtained conserves total vorticity and is a weak solution of the vorticity equation, making it an appropriate means for representing three-dimensional vortical flows with limited numbers of vortex singularities.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Physics of Fluids (ISSN 0031-9171); 31; 1838
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 61
    facet.materialart.
    Unknown
    Rain simulation studies for high-intensity acoustic nose cavities (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Unarmed plastic projectiles can be equipped with small axisymmetric cavities for the generation of intense tones that are useful in training maneuvers. Attention is presently given to the simulation of rainfall in an airstream and the effect of rain droplet impingement on the nose of projectiles, and especially to any penetration or accumulation of water at the base of the cavity that might increase the fundamental cavity frequency and/or reduce the intensity of sound production during rain conditions.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Aircraft (ISSN 0021-8669); 25; 281-283
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 62
    facet.materialart.
    Unknown
    Impact-driven supply of sodium and potassium to the atmosphere of Mercury (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The Mercury atmosphere is supplied with sodium atoms from both impacting meteoroids and the impacted regolith; the production of vaporized sodium due to such impact varies with the instantaneous distance of Mercury from the sun, in a way that differs from the distance-dependence of those source-and-sink processes driven by solar radiation. Such impact-driven vaporization will yield the Na/K ratio noted in the Mercury atmosphere only if both the meteoroids and the regolith of the planet are deficient in K relative to other solar system objects sampled, other than comets.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus (ISSN 0019-1035); 75; 156-170
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 63
    facet.materialart.
    Unknown
    Enceladus - Implications of its unusual photometric properties (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Voyager 1 and 2 images are used to ascertain the photometric properties of Enceladus up to a 43-deg phase angle. The lack of correlation noted between spectrophotometric properties and terrain type indicates that optical characteristics result from a recently-deposited, ubiquitous surface layer that may have originated on the E-ring of Saturn. Enceladus' distinctive phase and photometric functions can be accounted for by the high degree of surface multiple scattering; observations to date indicate that the Enceladus regolith's textural characteristics are similar to those of other icy satellites of Saturn.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus (ISSN 0019-1035); 75; 113-126
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 64
    facet.materialart.
    Unknown
    Large-amplitude photometric variations of Nereid (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Photometric UVBRI and astrometric data on Nereid were collected in June, 1987 using the 0.9-m telescope and CCD camera at the Cerro Tololo Inter-American Observatory. Four astrometric positions and UVBRI reflectances spanning eight days were obtained. From these data, an unusual reflectance spectrum for Nereid was determined. Variability of Nereid was observed in all bandpasses, with an amplitude greater than 1.5 mag and a probable period of between 8 and 24 hr.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Nature (ISSN 0028-0836); 333; 436-438
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 65
    facet.materialart.
    Unknown
    Aeolian weathering of Venusian surface materials - Preliminary results from laboratory simulations (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: An attempt is made to duplicate the atmospheric temperature, pressure, and approximate gas composition of all surface elevations on Venus by means of a simulator environment in which particles are impacted against rock targets as a way of studying planetary aeolian processes. While particles are abraded even at the low impact velocities envisioned for Venus, the same particles do not generate basaltic rock abrasion for impact velocities lower than 1 m/sec; comminution debris is instead transferred onto rock surfaces to form an accretion layer. These phenomena are seen as functions of the greater than 660 K temperatures encountered.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus (ISSN 0019-1035); 74; 495-515
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 66
    facet.materialart.
    Unknown
    Runaway and moist greenhouse atmospheres and the evolution of earth and Venus (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: For the case of fully moisture-saturated and cloud-free conditions, the present one-dimensional climate model for the response of an earthlike atmosphere to large solar flux increases notes the critical solar flux at which runaway greenhouse (total evaporation of oceans) occurs to be 1.4 times the present flux at the earth's orbit, almost independently of the CO2 content of the atmophere. The value is, however, sensitive to the H2O absorption coefficient in the 8-12 micron window. Venus oceans may have been lost early on due to rapid water vapor photodissociation, followed by hydrogen escape into space.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus (ISSN 0019-1035); 74; 472-494
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 67
    facet.materialart.
    Unknown
    Vacuum weathering of sulfur - Temperature effects and applications to Io (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The effect of surface temperature on the initial transient and subsequent steady-state behavior of the vacuum-sublimation rate and the UV/visible spectral reflectance of frozen sulfur has been investigated. Surface temperature is found to be the dominant parameter controlling the rate of vacuum weathering of sulfur. The present results suggest that any freshly-frozen sulfur deposits on Io at typical Io hotspot temperatures should display major transient changes in color in a matter of hours to days. It is noted that these rapid changes in spectral reflectivity should be readily detectable by future high-resolution synotopic observations of Io spectrum in the UV/visible.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Geophysical Research Letters (ISSN 0094-8276); 15; 697-700
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 68
    facet.materialart.
    Unknown
    Equilibrium shapes of rotating spheroids and drop shape oscillations (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Recent work on the equilibrium shapes of a rotating spheroid and drop shape oscillations is reviewed. The related theoretical aspects of the equilibrium shapes of a rotating drop, the stability, shape oscillations, gravitational forces, and drop fission are examined. Experimental findings on figures of a rotating drop in an immiscible system, drop oscillations in an immiscible system, oscillations of a rotating drop, compound drop oscillations, and drop dynamics in space are addressed.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 69
    facet.materialart.
    Unknown
    Free and forced modes in the Martian atmosphere (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Computations are conducted for the periods of free modes in the Martian atmosphere with a view to the short atmospheric radiative damping time and the seasonal and interannual variation of globally representative temperatures, both of which differ from their terrestrial counterparts by an order of magnitude. Attention is given to the possibility of atmospheric resonance and the efficient excitation (or even the resonant amplification) of forced modes. A thermally-forced diurnal Kelvin wave is recommended as the most reasonable of several alternative explanations of the short-period transient mode that occurs just before, or during, Mars' great episodic dust storms.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research (ISSN 0148-0227); 93; 9452-946
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 70
    facet.materialart.
    Unknown
    Ti(3+) in meteoritic and synthetic hibonite (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: This paper describes the first direct determination (performed by electron spin resonance spectroscopy) of Ti(3+) in hibonite from inclusion SH-7 of the Murchison C2 chondrite and in synthetic hibonites of four compositions, three of which corresponded to the compositions of blue hibonites and one to that of an orange hibonite. The Ti(3+) concentration in the hibonite from SH-7 was found to range from 0.35 to 0.44 percent, while the Ti(3+) contents in three synthetic blue hibonites ranged from 0.02 to 0.64 percent. Orange hibonite contained no Ti(3+), supporting an earlier conclusion that the orange-to-blue transition is associated with the presence of Ti(3+). At constant temperature and oxygen fugacity, the Ti(3+)/Ti(4+) ratio in synthetic hibonites was found to increase with decreasing V, but was not strongly dependent on bulk Ti. Fe and Cr contents did not have a significant effect on the amount of Ti(3+).
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Geochimica et Cosmochimica Acta (ISSN 0016-7037); 52; 1479-149
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 71
    facet.materialart.
    Unknown
    Oxygen plasma effects on several liquid droplet radiator fluids (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Spacecraft and Rockets (ISSN 0022-4650); 25; 99-101
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 72
    facet.materialart.
    Unknown
    Remanent magnetism at Mars (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: It is shown that a strong case can be made for an intrinsic magnetic field of dynamo origin for Mars earlier in its history. The typical equatorial magnetic field intensity would have been equal to about 0.01-0.1 gauss. The earlier dynamo activity is no longer extant, but a significant remanent magnetic field may exist. A highly non-dipole magnetic field could result from the remanent magnetization of the surface. Remanent magnetization may thus play an important role in the Mars solar wind interactions, in contrast to Venus with its surface temperatures above the Curie point. The anomalous characteristics of Mars'solar wind interaction compared to that of Venus may be explicable on this basis.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Geophysical Research Letters (ISSN 0094-8276); 15; 737-739
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 73
    facet.materialart.
    Unknown
    Solutions of one-dimensional steady nozzle flow revisited (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: A formulation is presented by which any iteration process for obtaining the entropy increase in the flow of a one-dimensional steady nozzle is eliminated, and the simple solution of a quadratic equation is obtained. The proper parameters are then explicitly seen in the equation, and their effects on the solution are easily determined. Since only one root of the equation is physically admissible, entropy production, and therefore the shock wave, are uniquely determined by this set of parameters.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA Journal (ISSN 0001-1452); 26; 625-628
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 74
    facet.materialart.
    Unknown
    Gravity waves in the upper atmosphere of Venus (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The transfer function model of Mayr et al. (1984, 1987) for a dissipative multiconstituent atmosphere on earth was modified to describe gravity waves in the thermosphere of Venus in terms of spherical and Fourier harmonics. This model is used to interpret density perturbations in CO2, O, and He which were observed with the orbital neutral mass spectrometer on Pioneer Venus. Results indicate that, in agreement with observations, for localized sources in the lower atmosphere and thermosphere of the same magnitude day and night, the computed wave amplitudes at satellite altitudes are about a factor of 3 to 5 larger during the night than during the day (due to the large night to day increase in the thermospheric temperature); waves excited in the lower atmosphere propagate more obliquely, and geometric attenuation and dissipation are less important than for the thermosphere. Due to wind-induced diffusion, the computed wave amplitudes for CO2, O, and He are of comparable magnitude (with the magnitude of CO2 being the largest).
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research (ISSN 0148-0227); 93; 11247-11
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 75
    facet.materialart.
    Unknown
    Wavelike perturbations observed in the neutral thermosphere of Venus (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Wavelike perturbations are evident in the neutral thermosphere measurements of He, N, O, N2, and CO2 by the Pioneer Venus orbiter neutral mass spectrometer. In the wavelength range from 100 to 600 km, the amplitudes of the various species are comparable in magnitude, with CO2 having the largest amplitude, and with helium out of phase with respect to the heavier species. On the dayside, the small-scale variations of CO2 and N2 increase with increasing altitude from 170 to 210 km, with CO2 having the largest slope. Simple and complex wave structures are observed, including wave trains and pulselike events. There is more activity during nighttime than during daytime, and larger values of the activity occur in the vicinity of the predawn and postdusk terminator sectors. Below 160 km, the standard deviation of the CO2 density on the nightside is 12 percent, about 3 times the daytime value. The data are consistent with the interpretation that the density perturbation are due to gravity waves propagating upward from the lower thermosphere.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research (ISSN 0148-0227); 93; 11237-11
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 76
    facet.materialart.
    Unknown
    The distribution and significance of evaporitic weathering products on Antarctic meteorites (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: This paper examines the occurrence of white evaporitic deposits on Antarctic meteorites from the U.S. collection, as a function of meteorite compositional group and weathering category. Evaporites occur with unusual frequency on carbonaceous chondrites. Almost two-thirds of all evaporite-bearing meteorites belong to weathering categories A, A/B, and B. Where chemical data were available, surficial evaporite deposits could be associated with elemental anomalies in meteorite interiors.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Meteoritics (ISSN 0026-1114); 23; 151-159
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 77
    facet.materialart.
    Unknown
    Microbeam analysis of four chondritic interplanetary dust particles for major elements, carbon and oxygen (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Chemical compositions determined using electron excited X-rays are reported for four interplanetary dust particles collected in the stratosphere. These analyses include measurements of carbon and oxygen abundances which are important elements in these primitive materials. Spot analyses show very heterogeneous compositions on a micrometer scale although average composition approaches that of C1 carbonaceous chondrites. While the spot analyses show intermediate compositions between cometary dust and carbonaceous chondrites, the heterogeneity more closely resembles that of comet Halley dust particles.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Meteoritics (ISSN 0026-1114); 23; 113-121
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 78
    facet.materialart.
    Unknown
    Karhunen-Loeve expansion of Burgers' model of turbulence (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The properties of the Karhunen-Loeve expansion of a strongly inhomogeneous random process are examined with emphasis on applications to turbulent flow fields. The ability of the KL expansion to represent functions that have both slow and rapid variations in a relatively small number of expansion terms is tested on a one-dimensional model based on the forced Burgers' equation. The rate of the convergence of the expansion is evaluated, and its dependence on the Reynolds number is determined. It is shown that the KL eigenfunctions possess wall boundary layers attached to outer structures that are independent of the Reynolds number (at high Reynolds numbers). It is also shown that the spectrum of eigenvalues is broad at large Reynolds numbers, requiring many terms to represent higher-order derivatives of the function.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Physics of Fluids (ISSN 0031-9171); 31; 2573-258
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 79
    facet.materialart.
    Unknown
    Cloud microphysics of the giant planets (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The characteristic time constants for the atmospheres of the giant planets were compared for the purpose of finding analogs for clouds in the atmospheres of these planets among the several types of cloud systems found on earth. The NH3 clouds on Jupiter and Saturn were found to be weakly precipitating systems, similar to the thicker cirrus clouds on earth, while the H2O clouds were found to be much more massive than the water clouds on earth. The CH4 and H2O clouds on Uranus and Neptune are completely unlike any cloud on earth, being 10 to 100 times more massive than the densest water clouds on earth. It is concluded that, while the microphysical characteristics of the clouds on Jupiter and Saturn are comparable to those of terrestrial stratus and cumulus clouds, the massive clouds on Uranus and Neptune reach conditions unlike anything on earth.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of the Atmospheric Sciences (ISSN 0022-4928); 45; 2066-208
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 80
    facet.materialart.
    Unknown
    Particle properties and the large-scale structure of planetary rings - Rebound characteristics and viscosity (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The present treatment of the apparently paradoxical reversal of momentum transport, or 'negative viscosity', in such swarms of particles on Keplerian orbits as planetary rings, illuminates the importance of particles' physical properties. Even the slightest deviation from the idealized (uniform, highly elastic, perfectly slippery, spherical) particles will affect viscosity, yielding predictions that are inconsistent with the observed ring structure. It is presently suggested that the size of the larger bodies in the rings determines random velocities, viscosity, and a substantial portion of ring structural characteristics.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus (ISSN 0019-1035); 75; 527-539
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 81
    facet.materialart.
    Unknown
    Geologic implications of spectrophotometric measurements of Europa (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Photometric functions and reflectances have been obtained from spectrophotometric measurements of Voyager images of Europa for (1) six mapped geologic terrains, (2) three types of lineaments, and (3) the brown spots. The results thus obtained suggest that Europa's materials fall into two main categories: a comparatively clean ice that constitutes the plains, and a darker and redder, silicate-rich material that makes up the brown spots and the wedge-shaped bands. Reflectance profiles obtained across the wedge-shaped bands and triple bands indicate similar albedo and color changes, implying similar structures for both of these features.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus (ISSN 0019-1035); 75; 437-449
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 82
    facet.materialart.
    Unknown
    Voyager 2 imaging eclipse observations of the Jovian high altitude haze (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: High stratospheric haze layer characteristics are presently explored in view of Voyager 2 wide-angle camera images of the Jupiter northern hemisphere dawn and dusk limbs. It is noted that such phenomena as particle size, refractive index, haze top altitude, and density have major effects on the intensity of scattered light; a unique solution specifying each of these is not possible. Important limits on the altitude of the haze top and haze extinction coefficients in the high stratosphere are nevertheless derived. The images show considerable, unanticipated differences between the dawn and dusk limbs at high latitude, suggesting a dynamically active upper atmosphere.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus (ISSN 0019-1035); 75; 381-398
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 83
    facet.materialart.
    Unknown
    Infrared processes in the Jovian auroral zone (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: In the present theoretical model of the Jovian auroral zone's CH4 and H2 vibrational excitation and deexitation processes, the calculation of the emission intensities of nu3 and nu4 bands of CH3 assume that electrons are the bombarding particles. The most uncertain part of the model calculation involves the energy flux spectrum of incident electrons on the auroral zone. Comparisons with Voyager 1 IRIS observations indicate a domination of the nonthermal, directly or indirectly particle bombardment-derived emission by the thermal emission of the CH4 band.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus (ISSN 0019-1035); 75; 399-408
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 84
    facet.materialart.
    Unknown
    On the nonlinear interaction of Goertler vortices and Tollmien-Schlichting waves in curved channel flows at finite Reynolds numbers (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The flow in a two-dimensional curved channel driven by an azimuthal pressure gradient can become linearly unstable due to axisymmetric perturbations and/or nonaxisymmetric perturbations depending on the curvature of the channel and the Reynolds number. For a particular small value of curvature, the critical neighborhood of this curvature value and critical Reynolds number, nonlinear interactions occur between these perturbations. The Stuart-Watson approach is used to derive two coupled Landau equations for the amplitudes of these perturbations. The stability of the various possible states of these perturbations is shown through bifurcation diagrams. Emphasis is given to those cases which have relevance to external flows.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Fluid Mechanics (ISSN 0022-1120); 193; 569-595
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 85
    facet.materialart.
    Unknown
    Experimental and theoretical effects of nitrogen gas flow rate on liquid-jet atomization (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Propulsion and Power (ISSN 0748-4658); 4; 406-411
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 86
    facet.materialart.
    Unknown
    Solid-state ice volcanism on the satellites of Uranus (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Voyager images of the Uranian satellites Ariel and Miranda show flow features with morphologies indicating that ice has been extruded to the satellites' surfaces in the solid state. These images provide the first observational evidence for solid-state ice volcanism in the solar system. Topographic profiles have been measured across a number of flow features on Ariel. With a simple model of extrusion, spreading, and cooling of a viscous flow, the initial viscosity of the flow material is found to have been no more than about 10 to the 16th poise, far lower than expected for H2O ice at the ambient surface temperatures in the Uranian system. Sharply reduced viscosities may have resulted from incorporation of ices like NH3 or CH4 in the Uranian satellites.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science (ISSN 0036-8075); 241; 1322-132
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 87
    facet.materialart.
    Unknown
    Physical properties of the planet Mercury (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The global physical properties of Mercury are summarized with attention given to its figure and orbital parameters. The combination of properties suggests that Mercury has an extensive iron-rich core, possibly with a still-functioning dynamo, which is 42 percent of the interior by volume. Mercury's three major axes are comparable in size, indicating that the planet is a triaxial ellipsoid rather than an oblate spheroid. In terms of the domination of its surface by an intermediate plains terrane, it is more Venus- or Mars-like; however, due to the presence of a large metallic magnetic core, its interior may be more earth-like.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 88
    facet.materialart.
    Unknown
    Tharsis block tectonics on Mars (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The concept of block tectonics provides a framework for understanding many aspects of Tharsis and adjoining structures. This Tharsis block tectonics on Mars is manifested partly by mantle-related doming and partly by response to loading by subsequent volcanic construction. Although the origin of the volcanism from beneath Tharsis is a subject of controversy explanations have to include inhomogeneities in Martian internal structure, energy distribution, magma accumulation and motion below the lithosphere. Thermal convection can be seen as a necessary consequence for transient initial phase of Martian cooling. This produced part of the elevated topography with tensional stresses and graben systems radial to the main bulge. The linear grabens, radial to the Tharsis center, can be interpreted to indicate rift zones that define the crustal block boundaries. The load-induced stresses may then have contributed on further graben and ridge formation over an extended period of time.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Earth, Moon, and Planets (ISSN 0167-9295); 41; 201-216
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 89
    facet.materialart.
    Unknown
    Experimental study of thermocapillary flows in a thin liquid layer with heat fluxes imposed on the free surface (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: To study thermocapillary flows in a two-dimensional thin liquid layer with heat fluxes imposed on the free surface experimentally, a long tray configuration was employed to simulate the infinite layer. The surface temperature distribution due to thermocapillary convection for different flow regimes was measured and compared with theorectical predictions. A short tray configuration was also employed to study the end wall effects (insulating or conducting). The results show that, for a strong convection flow with an insulating wall as the boundary, the surface temperature distribution became quite uniform. Consequently, the thermocapillary driving force was greatly reduced. On the other hand, a strong fluid motion always existed adjacent to the conducting wall because of the large surface temperature gradient near the wall.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Metallurgical Transactions A - Physical Metallurgy and Materials Science (ISSN 0360-2133); 19A; 1895-189
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 90
    facet.materialart.
    Unknown
    Transfinite element methodology for nonlinear/linear transient thermal modelling/analysis - Progress and recent advances (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The 'transfinite element method' (TFEM) proposed by Tamma and Railkar (1987 and 1988) for the analysis of linear and nonlinear heat-transfer problems is described and demonstrated. The TFEM combines classical Galerkin and transform approaches with state-of-the-art FEMs to obtain a flexible hybrid modeling scheme. The fundamental principles of the TFEM and the derivation of the governing equations are reviewed, and numerical results for sample problems are presented in extensive graphs and briefly characterized. Problems analyzed include a square plate with a hole, a rectangular plate with natural and essential boundary conditions and varying thermal conductivity, the Space Shuttle thermal protection system, a bimaterial plate subjected to step temperature variations, and solidification in a semiinfinite liquid slab.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: International Journal for Numerical Methods in Engineering (ISSN 0029-5981); 25; 475-494
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 91
    facet.materialart.
    Unknown
    Accretional heating of the satellites of Saturn and Uranus (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: A model developed specifically for accretional heating of small icy satellites of massive planets was used to investigate the effects of various parameters on the accretional heating of the Saturn and Uranus satellites. It was shown that accretional heating is completely dominated by cisplanetary impactors, with substantial deposition of heat occurring well below a satellite's surface. Three parameters that have large uncertainties were found to affect accretional temperature profile: the Safronov parameter for cisplanetary impactors, the fraction of impactor energy deposited below the surface, and the exponent in the impactor size-distribution equation. For most satellites, the depth of maximum heating and the maximum temperature reached have smooth positive dependences on satellite size. Accretional heating of these satellites is insufficient to melt H2O ice, but, if NH3 or CH4 are present, accretional heating may produce a warm buoyant mobile zone tens of kilometers below the surface.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research (ISSN 0148-0227); 93; 8779-879
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 92
    facet.materialart.
    Unknown
    Geological observation of impact craters on Mars and the earth using remote-sensing methods (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: It has been suggested that future multispectral and radar remote sensing of Martian craters can be developed on the basis of studies of multispectral and radar signatures of earth craters which are reasonable analogues of the Martian varieties. The present paper is a contribution toward establishing a methodology for detecting the record of very fresh craters on Mars.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Astronomicheskii Vestnik (ISSN 0320-930X); 22; 213-228
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 93
    facet.materialart.
    Unknown
    Determination of convective diffusion heat/mass transfer rates to burner rig test targets comparable in size to cross-stream jet diameter (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: ASME, Transactions, Journal of Heat Transfer (ISSN 0022-1481); 110; 449-455
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 94
    facet.materialart.
    Unknown
    Measured line positions and strengths of methane between 5500 and 6180/cm (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Calculations for the positions and strengths of over 2000 methane absorption lines stronger than 0.0001/sq cm per atm have been obtained in the 5500-6180/cm spectral region. Spectra were obtained at room temperature using the Fourier transform spectrometer at the Kitt Peak National Observatory solar telescope. The 2nu3 band strength of C-12H4 was shown to be 1.641/sq cm per atm. A Herman-Wallis-type correction of 1 + 0.0298 m + 0.000536 sq m was also found.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Applied Optics (ISSN 0003-6935); 27; 4038-405
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 95
    facet.materialart.
    Unknown
    Reynolds-stress and dissipation-rate budgets in a turbulent channel flow (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The budgets for the Reynolds stresses and for the dissipation rate of the turbulence kinetic energy are computed using direct simulation data of a turbulent channel flow. The budget data reveal that all the terms in the budget become important close to the wall. For inhomogeneous pressure boundary conditions, the pressure-strain term is split into a return term, a rapid term, and a Stokes term. The Stokes term is important close to the wall. The rapid and return terms play different roles depending on the component of the term. A split of the velocity pressure-gradient term into a redistributive term and a diffusion term is proposed, which should be simpler to model. The budget data is used to test existing closure models for the pressure-strain term, the dissipation rate, and the transport rate. In general, further work is needed to improve the models.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Fluid Mechanics (ISSN 0022-1120); 194; 15-44
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 96
    facet.materialart.
    Unknown
    Discovery of sodium and potassium vapor in the atmosphere of the moon (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: A ground-based telescopic study of the lunar surface with high resolution spectroscopy has led to the discovery of sodium and potassium vapor 'atmospheres'. The scale height for the sodium atmosphere is 120 + or - 42 km, and for potassium 90 + or - 20 km; these values imply that the effective temperature of the two elements closely approximates that of the lunar surface. The sodium density at the south polar region is similar to that at the subsolar point, indicating widespread distribution of the vapor. The ratio of sodium to potassium densities, at 6 (+ or - 3):1, is close to the lunar surface ratio and suggests that the atmosphere originated in the vaporization of surface minerals.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science (ISSN 0036-8075); 241; 675-680
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 97
    facet.materialart.
    Unknown
    High temperatures in the early solar nebula (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: One fundamental controversy about terrestrial planet and asteroid formation is the discrepancy between meteoritical evidence for high temperatures (1500 to 2000 K) in the inner solar nebula, and much lower theoretical temperature predictions on the basis of models of viscous accretion disks that neglect compressional heating of infalling gas. It is shown here that rigorous numerical calculations of the collapse of a rotating, three-dimensional presolar nebula are capable of producing temperatures on the order of 1500 K in the asteroid region (2.5 astronomical units), in either nearly axisymmetric or strongly nonaxisymmetric nebula models. The latter models may permit significant thermal cycling of solid components in the early inner solar nebula.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science (ISSN 0036-8075); 241; 565-567
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 98
    facet.materialart.
    Unknown
    Transient radiative cooling of an absorbing and scattering cylinder - A separable solution (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: A cylindrical region filled with absorbing-emitting material is cooled by radiation to surroundings at a much lower temperature. A solution is found showing that, for each set of parameters, the transient radial temperature distribution reaches a fixed shape, although the temperatures are decreasing with time. This 'fully developed' transient region is characterized by having a constant emittance based on instantaneous values of the cylinder heat loss and mean temperature. This emittance depends only on the optical radius of the cylinder and the scattering albedo. The emittance is lower than that for a cylinder at uniform temperature. This arises from the larger local cooling and, hence, reduced temperatures of the outer layers of the cylinder. An examination of this transient emittance provides the ranges of parameters within which the simplification can be made that the cylinder has uniform radial temperature distribution throughout the cooling process.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Thermophysics and Heat Transfer (ISSN 0887-8722); 2; 110-117
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 99
    facet.materialart.
    Unknown
    Implications of the GSFC Q3 model for trapped particle motion (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The Uranus magnetic field model of Connerney et al. (1987), designated GSFC Q3, is used to compute field geometric invariant parameters that determine the adiabatic motion of energetic charged particles trapped in the Uranian magnetosphere, performing computations only for points located along the Voyager 2 flyby trajectory. The L-shell values computed along the Voyager-2 trajectory were compared with L shell values corresponding to the orbital positions for the Uranian satellites Ariel, Umbriel, Miranda, and Titania for a time period centered on the time of the Voyager 2 closest approach to the planet. Bimodal distributions of L minima asociated with the orbital motion of the moons are obtained, thus complicating the model predictions and correlations with charged particle data. The location of charged particle absorption signatures associated with the sweeping effects of the Uranian satellites is reasonably predicted, but significant discrepancies remain which cannot be explained by Q3 model uncertainties.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research (ISSN 0148-0227); 93; 5505-551
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 100
    facet.materialart.
    Unknown
    Nonlinear vortex trail dynamics (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The nonlinear evolution of periodic disturbances on vortex trails is considered. In addition to following small initial perturbations, large amplitude initial disturbances of the vortex trails are also studied. It is shown that the equations support a rich variety of essentially nonlinear solutions including unbounded and quasisteady ones. These solutions are found to correspond to various modes of vortex clustering in the physical plane. At the close of the paper, comparisons of these results with recent numerical and experimental findings on the wakes behind stationary cylinders, and also transversely oscillating bluff objects, are made.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Physics of Fluids (ISSN 0031-9171); 31; 991-998
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...