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  • Inorganic Chemistry  (668)
  • LUNAR AND PLANETARY EXPLORATION  (549)
  • FLUID MECHANICS AND HEAT TRANSFER  (435)
  • 2015-2019
  • 1985-1989  (1,652)
  • 1965-1969
  • 1986  (1,652)
Collection
Keywords
Publisher
Years
  • 2015-2019
  • 1985-1989  (1,652)
  • 1965-1969
Year
  • 1
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    The Capillary Pumped Loop (CPL) GAS experiment G-471 (1986)
    In:  CASI
    Details
    Publication Date: 2009-11-16
    Description: The Capillary Pumped Loop (CPL) experiment, G-471 is a thermal control system with high density heat acquisition and transport capability. The CPL consists of two capillary pumped evaporators with integral heaters, a fluid loop charged with ammonia (NH3), a condenser plate (heat sink), and various control electronics. The purpose of the experiment is to demonstrate the capability of a capillary pumped system under zero gravity conditions for use in the thermal control of large scientific instruments, advanced orbiting spacecraft, and space station components.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: The 1985 Get Away Special Experimenter's Symposium; p 237-253
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  • 2
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    Thermocapillary flow and gaseous convection in microgravity: Results from GAS payload G-0518 (1986)
    In:  CASI
    Details
    Publication Date: 2006-06-12
    Description: Thermocapillary flow and gaseous convection in microgravity were investigated in GAS payload G-0518 during Space Shuttle Mission 41-D. A cylinder of paraffin was supported and heated differentially from its ends to induce a melt from solid to liquid and drive thermocapillary flow in the resulting liquid phase. Laminar thermocapillary flow was observed in the liquid paraffin and found to show a transition to time-dependent oscillatory motion at a Marangoni number of about Ma = 34000 with a period of approximately T = 8 seconds. In addition, free convection in a gas in microgravity was observed for the first time. The gaseous convection was caused by the thermal and/or velocity boundary layers present at the heater-liquid interface. Oscillation occurred in the gaseous convection simultaneously with those in the liquid, implying the two are strongly coupled. The gaseous convection may be driven by coupled thermocapillary flow/thermal expansion convection or microgravity bouyancy convection.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Goddard Space Flight Center The 1985 Get Away Special Experimenter's Symposium; p 293-301
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  • 3
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    GAS payload no. G-025: Study of liquid sloshing behaviour in microgravity (1986)
    In:  CASI
    Details
    Publication Date: 2006-06-12
    Description: The Get Away Special (GAS) G-025, which flew on shuttle Mission 51-G, examined the behavior of a liquid in a tank under microgravity conditions. The experiment is representative of phenomena occurring in satellite tanks with liquid propellants. A reference fluid in a hemispherical model tank will be subjected to linear acceleration inputs of known levels and frequencies, and the dynamic response of the tank liquid system was recorded. Preliminary analysis of the flight data indicates that the experiment functioned perfectly. The results will validate and refine mathematical models describing the dynamic characteristics of tank-fluid systems. This will in turn support the development of future spacecraft tanks, in particular the design of propellant management devices for surface tension tanks.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Goddard Space Flight Center The 1985 Get Away Special Experimenter's Symposium; p 165-176
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  • 4
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    Water ball collision (1986)
    In:  CASI
    Details
    Publication Date: 2006-06-12
    Description: What happens if a stainless steel ball hits a water ball in the weightless space ot the Universe? In other words, it was the objective of our experiments in the Space to observe the surface tension of liquid by means of making a solid collide with a liquid. Place a small volume of water between 2 glass sheets to make a thin water membrane: the 2 glass sheets cannot be separated unless an enormous force is applied. It is obvious from this phenomenom that the surface tension of water is far greater than presumed. On Earth, however, it is impossible in most cases to observe only the surface tension of liquid, because gravity always acts on the surface tension. Water and stainless steel balls were chosen the liquid and solids for the experiments. Because water is the liquid most familiar to us, its properties are well known. And it is also of great interest to compare its properties on the Earth with those in the weightless space.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Goddard Space Flight Center The 1985 Get Away Special Experimenter's Symposium; p 81-84
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  • 5
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    Planetary spectroscopy (1986)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Spectroscopic and spectrophotometric data on the atmospheres of comets, the outer planets, and Titan at ultraviolet to near-infrared wavelengths were acquired. These data support an effort aimed at characterizing the physical properties and distribution of aerosol particles in the atmospheres of these bodies. New spectrophotometry was acquired of Uranus at 0.2 lambda 0.3 micrometer with IUE; archival IUE spectrophotometry of Uranus and Neptune in this wavelength range was acquired and recalibrated. New estimates of radiometric Bond albedos and global energy budges of Uranus, Neptune and Titan were published.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA, Washington Reports of Planetary Astronomy, 1985; p 19
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  • 6
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    Infrared observations of outer planet satellites (1986)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Infrared observations were made of the outer planet satellites. These data provide vital information about the thermophysical properties of satellite surfaces, including internal heat sources for Io. Observations include both broad and narrow band measurements in the 2 to 20 micrometer spectral range. Types of observation and target priority were determined to make maximum use of existing data from Voyager and other missions, on-going and planned missions such as Galileo, were supported and techniques and data for planning new missions and instrumentation were developed.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA, Washington Reports of Planetary Astronomy, 1985; p 38
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  • 7
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    Shuttle Continuous Open Wind Tunnel (SCOWT) (1986)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The aerodynamic and heat transfer coefficients are studied within the range of thermo-fluid-dynamic conditions experienced by a satellite during Tethered Satellite System (TSS) atmospheric flights. The gasdynamic processes occuring downstream of the bow wave standing in front of the satellite are also studied. The knowledge of the chemistry and physics of the upper atmosphere related to satellite aerothermodynamics is furthered. The existence of an overshooting of the air drag coefficient of the sphere in the transition regime is validated. A complete set of measurements is performed in order to provide the data base to develop and validate theoretical models of free molecule transition flow fields.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA, Washington Applications of Tethers in Space. Workshop Proceedings, Vol. 2; p 225-249
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  • 8
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    Fluid behavior in microgravity (1986)
    In:  CASI
    Details
    Publication Date: 2006-06-11
    Description: An experiment designed to study some fundamental aspects of microgravity fluid dynamics has been built and is scheduled for flight. The purpose of the experiment is to investigate differences in behavior of wetting and nonwetting fluid systems at low Bond numbers. Methods were developed to determine liquid quantity, estimate vapor contact area and measure liquid layer thickness. Both the responses of the fluid systems to external perturbations and the transfer of liquid through a connection between two containers can be studied.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Goddard Space Flight Center The 1985 Get Away Special Experimenter's Symposium; p 33-40
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  • 9
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    Studies of extended planetary atmospheres (1986)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Telescopic observations were made of gases and plasmas in the Jupiter system, and related phenomena such as the recently-discovered sodium atmosphere of Mercury. Sodium absorption in Io's atmosphere was observed to distances as large as 5 Io radii during the mutual-eclipse season of the Jovian satellites. Analysis of Jovian disk spectra has proceeded, as planned, from an emphasis on the H2 ortho-para ratio to analysis of methane absorptions and determination of cloud structure. Several 2-channel photometers were constructed in 1978 for the Uranus event at which the rings were discovered and a smaller, single-channel unit was built more recently. Although the photometers themselves are still fully usable, the data-acquisition systems have major deficiencies.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA, Washington Reports of Planetary Astronomy, 1985; p 34-35
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  • 10
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    Search for volatiles in the surface of icy satellites (1986)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: It is proposed to measure the reflectance spectra of the icy satellites of Jupiter, Saturn and Uranus in the spectral region 1.8 to 2.4 micrometers. These observations use the new Cooled Grating Array Spectrometer using a 32-element InSb photodiode array detector and produce spectra of higher resolution and precision than any data yet obtained; the ultimate scientific objective is to search for the signatures of methane clathrate, ammonium hydroxide or carbon monoxide clathrate (compounds predicted to exist on icy surfaces in the outer solar system by several theories of formation of these bodies) in the region of the spectrum where water ice has a relative maximum in reflectance. At the very least, these data will allow upper limits to be placed on the amount of these chemical species that can be present. The specific targets is Europa, Ganymede, Enceladus, Ariel and Titania, bodies that have the highest probability of having some or all of these volatiles on their surface according to current formation models.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA, Washington Reports of Planetary Astronomy, 1985; p 20
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  • 11
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    An analysis of ullage heat transfer in the orbital refueling system (1986)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The Orbital Refueling System was an experiment flown on Shuttle Mission STS 41-G in October, 1984. Liquid hydrazine fuel was transferred back and forth from one spherical bladder tank to another using pressurized nitrogen as the driving force. Compressive heating of the ullage gas in the receiving tank could lead to a hazardous situation if any hydrazine leaked through to the ullage side of the bladder and was heated above about 175 F, where it can undergo spontaneous exothermic decomposition. Early analysis of the flight data indicated that the ullage compression process was much closer to an isothermal than an adiabatic one. In this study, a thorough review of the pertinent literature was used to make an a priori best-estimate for the ullage gas heat transfer coefficient (defining the Nusselt Number as a function of Reynolds and Rayleigh Numbers). Experimental data from the flight were analyzed in detail. It is evident that there is considerably more heat transfer than can be accounted for by conduction alone, but the observed increases do not correlate well with Reynolds Number, Rayleigh Number or vehicle acceleration. There are large gaps in the present understanding of convective heat transfer in closed containers with internal heat generation, especially in the presence of vibrations or other random disturbances. A program of experiments to fill in these gaps is suggested, covering both ground and orbital environments.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Johnson Space Center NASA/American Society for Engineering Educati; NASA. Johnson Space
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  • 12
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    New techniques for the detection and capture of micrometeoroids (1986)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: In order to understand the origin and distribution of the biogenic elements and their compounds in the solar system, it will be necessary to study material from many classes of objects. Chemical, elemental, and isotopic measurements of returned samples of comets, asteroids, and possibly extra-solar system dust clouds would provide information on a particularly important class: the primitive objects. Extraterrestrial micron-sized particles in the vicinity of earth are one source of such materials that might otherwise be inaccessible. The Space Station appears to be an eminently suitable platform from which to collect and detect these various particles. The primary challenge, however, is to collect intact, uncontaminated particles which will be encounted at tens of kilometers per seconds. A concept for a micrometeoroid detector that could be deployed at a Space Station has been developed which uses a large area detector plate implanted with acoustic transducers. When an impact event occurs, the resulting signal is subjected to spectral analysis providing positive detection, momentum information, and angle of incidence. The primary advantage of this detector is the large area which increases the probability of measuring events.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA, Washington Second Symposium on Chemical Evolution and the Origin and Evolution of Life; p 59
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  • 13
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    Experimental basis for a Titan probe organic analysis (1986)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The recent Voyager flyby of Titan produced evidence for at least nine organic compounds in that atmosphere that are heavier than methane. Several models of Titan's atmosphere, as well as laboratory simulations, suggest the presence of organics considerably more complex that those observed. To ensure that the in situ measurements are definitive with respect to Titan's atmosphere, experiment concepts, and the related instrumentation, must be carefully developed specifically for such a mission. To this end, the possible composition of the environment to be analyzed must be bracketed and model samples must be provided for instrumentation development studies. Laboratory studies to define the optimum flight experiment and sampling strategy for a Titan entry probe are currently being conducted. Titan mixtures are being subjected to a variety of energy sources including high voltage electron from a DC discharge, high current electric shock, and laser detonation. Gaseous and solid products are produced which are then analyzed. Samples from these experiements are also provided to candidate flight experiments as models for instrument development studies. Preliminary results show that existing theoretical models for chemistry in Titan's atmosphere cannot adequetely explain the presence and abundance of all trace gases observed in these experiments.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA, Washington Second Symposium on Chemical Evolution and the Origin and Evolution of Life; p 52
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  • 14
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    Visible phase curves of Uranus and Neptune and scattering in their atmospheres (1986)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The Voyager 1 and Voyager 2 narrow angle cameras have been imaging Uranus and Neptune (through several filters) from distances of several AU for the past four years. The justification for this is to determine the way in which the albedoes of the two planets vary with angle from the sun. The Voyager 1 spacecraft has already reached a phase angle of approx. 40 deg. for Neptune and approx. 70 deg. for Uranus. The albedo of a gaseous planet depends on the phase angle (angle from the sun through the planet to the observer), the color being observed, and the vertical distribution and nature of aerosols and clouds in the atmosphere of the planet. Since the colors are known and the phase angles, and phase curves will be used to constrain models of the aerosol and cloud structrures of Uranus and Neptune. A knowledge of the way albedo varies with phase angle allows one to compute the total amount of sunlight being absorbed by a planet. With knowledge of the solar flux incident on the planet and knowledge of how much infrared is being emitted by the planet (at least in the direction of the Earth and sun) one can determine a rough extimate of the internal heat source of the planet. Although Jupiter and Saturn have measured internal heat sources of magnitude comparable to their absorbed energy from the sun, preliminary results indicate that Uranus may not have an internal heat and that Neptune if it has one that heat source is small.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA, Washington Reports of Planetary Astronomy, 1985; p 64
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  • 15
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    Planetary research at Lowell Observatory (1986)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Narrowband CCD profiles of C2 and grains in several comets (including P/Halley and P/Giacobini-Zinner) were performed. Rotational light curves were made of Comet P/Arend-Rigaux (visible and infrared) yielding the size, shape, albedo, and rotation period of the nucleus. Production rates were measured as a function of heliocentric distance for OH, CN, and C2 in P/Giacobini-Zinner and for OH, NH, CN, C3, and C2 in P/Halley. Detection and measurement was made of forbidden (O I) lines near 6300 and 5577 A in P/Halley, permitting the production rate of oxygen from CO to be distinguished from that from H2O. Identification of C-12C-13 lines in cometary spectra indicating a possible enrichment of C-13 over the telluric value was made. An assessment of techniques for detecting (determining the existence of) a trans-Neptunian comet belt is included.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA, Washington Reports of Planetary Astronomy, 1985; p 68-70
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  • 16
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    Modeling and investigative studies of Jovian low frequency emissions (1986)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The Voyager data in a newly produced noise-reduced and recalibrated format has been received. New color spectrograms were developed on high resolution color terminals which display this data. The production of these new spectrograms utilizing the new format data is quite important, because it eliminates a serious problem of noise contamination and miscalibration in the old data set. In addition, a new Jovian plasma model was introduced, which includes the Io torus and accounts for 7 ionic species. The new plasma model is important in the ray tracing of hectometric (HOM) and kilometric (KOM) radiation which may be influenced by the Io torus.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA, Washington Reports of Planetary Astronomy, 1985; p 44-45
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  • 17
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    Long-term changes in reflectivity and larger scale motions in the atmospheres of Jupiter and Saturn (1986)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: A multi-color, broad-band photographic program for monitoring atmospheric variability of Jupiter and Saturn with the 61-cm, f/75 telescope was continued. The archivial product consists of approximately 20 sequential images on 3 1/4 x 4 1/4 glass plates with a plate scale of 4.53 arc sec/mm. An eleven-step sensitometric wedge, recorded times of acquisition, and fiducial marks which determine the orientation of the plate, are recorded on each individual plate. This allows accurate positional measurements, as well as detailed relative surface brightness determinations. Detailed measurements of the Red Spot are being utilized in a study of zonal velocity variation and the ability to predict the longitude of the Red Spot during the Galileo mission. An ongoing 5-color series of Saturn has been maintained to map the seasonal changes in the belt-zone reflectivity. Digitization of a series of blue images containing the Red Spot and a series of red and blue images excluding the Red Spot are being processed and reduced to normalized surface brightness maps. This data is being utilized to map time-dependent brightness variations of selected features, belts, and ones.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA, Washington Reports of Planetary Astronomy, 1985; p 17-18
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  • 18
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    Interiors of the giant planets (1986)
    In:  CASI
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    Publication Date: 2006-02-14
    Description: The interior structure of the Jovian planets was studied by means of observational data obtained by ground-based astronomy. Recent work was oriented toward a determination of oblateness from occultation measurements of the shape of planetary atmospheres. This provides a determination of the degree of central condensation of the planet, which is then compared with interior models and theoretical equations of state. As a serendipitous result of the attempts to measure the oblateness of Neptune, a partial Neptune ring (or arc) was discovered following an occultation observation on July 22, 1984. During 1985, older observations were reexamined to determine whether Neptune arcs had been detected (but not identified) during previous occultations. It appears that Neptunian arcs may locally imitate Uranian rings, with an 1981 event resembling Uranus' epsilon ring, while an 1984 event was more similar to the thinner Uranian rings such as the alpha ring.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA, Washington Reports of Planetary Astronomy, 1985; p 32-33
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  • 19
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    Theoretical and observational planetary physics (1986)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: This program supports NASA's deep space exploration missions, particularly those to the outer Solar System, and also NASA's Earth-orbital astronomy missions, using ground-based observations, primarily with the NASA IRTF at Mauna Kea, Hawaii, and also with such instruments as the Kitt Peak 4 meter Mayall telescope and the NRAO VLA facility in Socorro, New Mexico. An important component of the program is the physical interpretation of the observations. There were two major scientific discoveries resulting from 8 micrometer observations of Jupiter. The first is that at that wavelength there are two spots, one near each magnetic pole, which are typically the brightest and therefore warmest places on the planet. The effect is clearly due to precipitating high energy magnetospheric particles. A second ground-based discovery is that in 1985, Jupiter exhibited low latitude (+ or - 18 deg.) stratospheric wave structure.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA, Washington Reports of Planetary Astronomy, 1985; p 21-22
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  • 20
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    Radiative transfer in planetary atmospheres (1986)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The research effort was concentrated toward comet P/Halley, although observations of other comets including Giacobini-Zinner, Hartley-Good and Thiele were made as opportunities arise. In preparing for the apparition of P/Halley, detailed predictions for the emission in the 18 cm OH transitions were made in order to assist observers and to indicate what type of data would be particularly valuable. Likewise, since occultations by the comet of background radio sources can provide unique types of information, the tracks of P/Halley and P/Giacobini-Zinner were surveyed with the NRAO Very Large Array, background sources were mapped, and a catalogue of occulted sources published. Beginning in September, 1985, regular observations of the 18 cm OH lines have been made for P/Halley using the 43 m antenna of the NRAO in Greenbank, West Virginia. These data promise to provide the most accurate time sequence for the OH emission for any comet ever obtained at radio wavelengths. From the linewidth and shape, information is obtained on the kinetics of the gas in the cometary coma. An extensive series of observations have been undertaken with 14 m antenna to study emission from the HCN molecule in P/Halley. These data provide the first definitive detection of this component of the cometary ices. Interesting variations in the production of HCN were observed with time scales less than a day. Likewise, there appeared to be variations in the ratio of the hyperfine components of the J = 1-0 transition.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA, Washington Reports of Planetary Astronomy, 1985; p 96-97
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  • 21
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    Materials considerations in the design of a metal-hydride heat pump for an advanced extravehicular mobility unit (1986)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: A metal-hydride heat pump (HHP) has been proposed to provide an advanced regenerable nonventing thermal sink for the liquid-cooled garment worn during an extravehicular activity (EVA). The conceptual design indicates that there is a potential for significant advantages over the one presently being used by shuttle crew personnel as well as those that have been proposed for future use with the space station. Compared to other heat pump designs, a HHP offers the potential for extended use with no electrical power requirements during the EVA. In addition, a reliable, compact design is possible due to the absence of moving parts other than high-reliability check valves. Because there are many subtleties in the properties of metal hydrides for heat pump applications, it is essential that a prototype hydride heat pump be constructed with the selected materials before a committment is made for the final design. Particular care must be given to the evaporator heat exchanger worn by the astronaut since the performance of hydride heat pumps is generally heat transfer limited.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Johnson Space Center NASA/American Society for Engineering Educati; NASA. Johnson Space
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  • 22
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    Chronology and isotopic geochemistry of apollo 14 basalts and Skaergard Gabbro, Eastern Greenland (1986)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Work completed on Apollo 14 basalts has been published. The two dates obtained from these rocks comprised the oldest and two of the three oldest ages (4.1 and 4.3 billion years) known for lunar maria basalts; thus their ages are important in understanding the moon's earliest history. Owing to the antiquity of these rocks, two more fragments have been dated as part of a second ASEE/NASA SFF program. The new ages are 3.95 and 4.12 billion years, thus further establishing and amplifying the earlier results. This work, although perhaps more interesting for its chronologic information, was begun as a test of chemical and petrographic models. Fragments of Apollo basalt were placed into five categories, based on petrologic and chemical, especially rare-earth element, composition. Isotopic studies were begun in an attempt to determine if the five groups of basalts were related by age or initial isotopic composition (isotopic composition of lava at time of extrusion). Although a few of the representatives of the five groups have the same age and/or initial strontium-isotopic composition, within the analtytical uncertainties, most apparently are unrelated. Petrologic implications of these data will be published in an appropriate journal.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA. Johnson Space Center NASA/American Society for Engineering Educatio; NASA. Johnson Space
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  • 23
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    Condensation heat transfer under a microgravity environment (1986)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: A description of the condensation heat transfer process in microgravity is given. A review of the literature is also reported. The most essential element of condensation heat transfer in microgravity is the condensate removal mechanism. Two mechanisms for condensate removal are analyzed by looking into two problems. The first problem is concerned with film condensation on a flat porous plate with the condensate being removed by suction at the wall. The second problem is an analytical prediction of the heat transfer coefficient for condensing annular flows with the condensate film driven by the vapor shear. It is concluded that both suction and vapor shear can effectively drain the condensate to ensure continuous operation of the condensers operated under a microgravity environment. It is recommended that zero-g flight experiments be carried out to verify the prediction made in the present report. The results contained in this report should also aid in the design of future space condensers.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Johnson Space Center NASA/American Society for Engineering Educati; NASA. Johnson Space
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  • 24
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    Measurements of physical properties of model Titan atmospheres (1986)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: One aspect of the study of Titan's atmosphere is the elucidation of the chemical and physical nature of the aerosols. In order to facilitate this, a program to produce laboratory synthesized model materials for Titan's aerosol and to study their chemical and physical properties is now in progress. Various processes, including electric discharge, photolysis by ultraviolet light, and irradiation by energetic particles, will be used to produce the materials. A first set of experiments where a nominal Titan mixture (97%N2, 3% CH4, 0.2% H2) was subjected to pulsed high temperature shocks yielded a reddish brown waxy solid. This material was subjected to pyrolysis/gas chromatography, a technique that has been proposed as a method for analysis of the Titan aerosols. Preliminary results show the material to consist of simple hydrocarbons but little else, at least up to temperatures of 600 C. Since the material was colored, compounds other than those mentioned above must be present.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA, Washington Second Symposium on Chemical Evolution and the Origin and Evolution of Life; p 50
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  • 25
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    Flow regimes in a shallow rotating cylindrical annulus with temperature gradients imposed on the horizontal boundaries (1986)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Experimental flow regime diagrams are determined for a new rotating cylindrical annulus configuration which permits a measure of control over the internal vertical temperature gradient. The new annulus has radial temperature gradients imposed on plane horizontal thermally conducting endwalls (with the cylindrical sidewalls as insulators) and is considered to be more relevant to atmospheric dynamics studies than the classical cylindrical annulus. Observations have revealed that, in addition to the axisymmetric flow and nonaxisymmetric baroclinic wave flow which occur in the classical annulus, two additional nonaxisymmetric flow types occur in the new annulus: boundary-layer thermal convection and deep thermal convection. Flow regime diagrams for three different values of the imposed vertical temperature difference are presented, and explanations for the flow transitions are offered. The new annulus provides scientific backup for the proposed Atmospheric General Circulation Experiment for Spacelab. The apparatus diagram is included.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Fluid Mechanics (ISSN 0022-1120); 172; 401-418
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  • 26
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    Mass spectrometric study of the mercury isotopes in the Allende meteorite (1986)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Isotopic abundance ratios for mercury were determined by mass spectrometry in six samples of bulk material and in one sample of chondrules from the Allende meteorite. A primary purpose of the work was to attempt to verify the anomalous ratios reported for Hg-196/Hg-202 by neutron activation. Measurements were made on the mercury released at temperatures of 250, 450, 600 C, and in some cases, higher temperatures. The precision of the measurements was such that if an anomaly of the magnitude reported exists, it should have been seen. The isotopic abundance ratios for the other mercury isotopes were also measured. Within the errors of measurement these agreed with normal terrestrial values.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research (ISSN 0148-0227); 91; E124-E12
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  • 27
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    Linear volcanic features at Alba Patera, Mars - Probable spatter ridges (1986)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A number of extensive linear constructional features occur on the north and east flanks of Alba Patera. They are found in a 150-km-wide zone and comprise aligned ridge elements that are locally associated with short volcanic flows. They are among the youngest volcanic features in the region and are believed to be Martian analogs of terrestrial spatter ridges. On the basis of measurements made on Viking images, it appears that active volcanic fissures on Mars were larger than their terrestrial counterparts.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research (ISSN 0148-0227); 91; E159-E16
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  • 28
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    Shock-implanted noble gases - An experimental study with implications for the origin of Martian gases in shergottite meteorites (1986)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The shock-implantation of gases is studied by artificially shocking whole rock and power samples of terrestrial basalt to pressures of 2-40 GPa. Ar, Kr, Xe, and Ne were implanted into the silicate. It is observed that the amount of implanted gas is linearly proportional to its partial pressure over a pressure range of 0.0001 to 0.1 atmosphere. The fractionation effect in the implanted gas and the gas diffusion properties are examined. The amounts of gas that would have been implanted with 100 percent efficiency are calculated from the measured porosities of the power samples and are compared to observed abundances. It is determined that the implantation efficiencies are approximately 0.5 percent at 2 GPa, 7 percent at 5 GPa, and greater than 50 percent at both 20 and 35 GPa. The experimental data correlate with the shock implantation of Martian gases without mass fractionation into the shock-melted phase of meteorite EETA 79001.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research (ISSN 0148-0227); 91; E99-E114
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  • 29
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    Composition of the Cayley Formation at Apollo 16 as inferred from impact melt splashes (1986)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Abundances of major and trace elements and magnetic properties of 50 impact melt splashes (IMSs) from the Apollo 16 landing site are analzyed to determine the composition of their meteoritic component. MgO-Sc and Ca-Sc variation diagrams and least-squares mixing models are utilized to analyze the IMS, soil, and rock data. Consideration is given to progenitor lithologies of the IMS, the number of impact events represented by the IMS, and the heterogeneity of impact melts from single events. It is observed that the IMSs are composed of either a mixture of anorthosite and low-Sc impact melt rocks or anorthositic norite. It is determined that the surface Cayley layer is composed of TiO2, MgO, Sc, and La concentrations of 0.69, and 7.1 wt pct and 10.5 and 21.2 microg/g, respectively and 0.38 and 5.9 wt pct and 6.1 and 11.8 microg/g, respectively, for the subsurface Cayley layer. The Descartes Formation composition is estimated as TiO2, MgO, Sc, and La concentrations of 0.25, and 3.5 wt pct and 7.7 and 2.2 microg/g, respectively.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research (ISSN 0148-0227); 91; E21-E42
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  • 30
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    Apollo 16 impact-melt splashes - Petrography and major-element composition (1986)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Petrographic and major-element analyses are applied to 50 Apollo 16 impact-melt splash (IMS) samples in order to determine their origin and assess the nature of the subregolith source. The macroscopic analyses reveal that the IMSs exhibit a glassy appearance, but the textures range from holohyaline to hyalopilitic. Schlieren-rich glasses dominate the holohyaline areas, and the crystalline areas are mainly spherulitic. It is observed that most IMSs contain feldspathic monomineralic and lithic clasts and no regolithic materials. It is detected that the chemistry of most IMSs is not like the local regolith and appears to represent varied mixtures of VHA impact-melt breccias and anorthosite; the host rocks are mainly dimict breccias. It is concluded that the Cayley Formation is a polymict deposit composed of VHA impact-melt breccias and anorthosites. Tables revealing the macroscopic characteristics of the IMSs and the major-element composition of IMSs and various host rock are presented.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research (ISSN 0148-0227); 91; E3-E20
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  • 31
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    Lunar and Venusian radar bright rings (1986)
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    Publication Date: 2011-08-19
    Description: Twenty-one lunar craters have radar bright ring appearances which are analogous to eleven complete ring features in the earth-based 12.5 cm observations of Venus. Radar ring diameters and widths for the lunar and Venusian features overlap for sizes from 45 to 100 km. Radar bright areas for the lunar craters are associated with the slopes of the inner and outer rim walls, while level crater floors and level ejecta fields beyond the raised portion of the rim have average radar backscatter. It is proposed that the radar bright areas of the Venusian rings are also associated with the slopes on the rims of craters. The lunar craters have evolved to radar bright rings via mass wasting of crater rim walls and via post-impact flooding of crater floors. Aeolian deposits of fine-grained material on Venusian crater floors may produce radar scattering effects similar to lunar crater floor flooding. These Venusian aeolian deposits may preferentially cover blocky crater floors producing a radar bright ring appearance. It is proposed that the Venusian features with complete bright ring appearances and sizes less than 100 km are impact craters. They have the same sizes as lunar craters and could have evolved to radar bright rings via analogous surface processes.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Earth, Moon, and Planets (ISSN 0167-9295); 36; 167-185
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  • 32
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    Clay-mineraloid weathering products in Antarctic meteorites (1986)
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    Publication Date: 2011-08-19
    Description: The production of clay mineraloids (CMs) in the weathering of stony meteorites recovered in the Allan Hills and Elephant Moraine areas of Antarctica is investigated, applying electron microbeam analysis, pyrolysis/mass spectroscopy, X-ray diffractometry, and differential scanning calorimetry to whole-rock chips from two eucrites, two diogenites, and an H5 chondrite. The data are presented in tables, graphs, and photomicrographs and characterized in detail. Massive to incipient-vermicular CM formations with smectitelike or micalike compositions and indications of poor crystallization are observed and attributed to hydrocryogenic diagenesis (with little or no liquid water) on time scales of 10-1000 kyr. The need to take the compositional effects of weathering into account before attempting to reconstruct the preterrestrial histories of meteorites is stressed.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Geochimica et Cosmochimica Acta (ISSN 0016-7037); 50; 2215-222
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  • 33
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    The special relativistic shock tube (1986)
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    Publication Date: 2011-08-19
    Description: The shock-tube problem has served as a popular test for numerical hydrodynamics codes. The development of relativistic hydrodynamics codes has created a need for a similar test problem in relativistic hydrodynamics. The analytical solution to the special relativistic shock-tube problem is presented here. The relativistic shock-jump conditions and rarefaction solution which make up the shock tube are derived. The Newtonian limit of the calculations is given throughout.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Fluid Mechanics (ISSN 0022-1120); 171; 365-375
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  • 34
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    Measurement and prediction of model-rotor flowfields (1986)
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    Publication Date: 2011-08-19
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Aircraft (ISSN 0021-8669); 23; 843-851
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  • 35
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    Venus - Dead or alive? (1986)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: In situ nightside electric field observations from the Pioneer Venus Orbiter have been interpreted as evidence of extensive lightning in the lower atmosphere of Venus. The scenario, including proposed evidence of clustering of lightning over surface highland regions, has encouraged the acceptance of currently active volcanic output as part of several investigations of the dynamics and chemistry of the atmosphere and the geology of the planet. However, the correlation between the 100-hertz electric field events attributed to lightning and nightside ionization troughs resulting from the interaction of the solar wind with the ionosphere indicates that the noise results from locally generated plasma instabilities and not from any behavior of the lower atmosphere. Furthemore, analysis of the spatial distribution of the noise shows that it is not clustered over highland topography, but rather occurs at random throughout the latitude and longitude regions sampled by the orbiter during the first 5 years of operation, from 1978 to 1984. Thus the electric field observations do not identify lightning and do not provide a basis for inferring the presence of currently active volcanic output. In the absence of known evidence to the contrary, it appears that Venus is no longer active.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science (ISSN 0036-8075); 234; 1087-109
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  • 36
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    Scaling relations for heating during gliding entry at parabolic speed (1986)
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    Publication Date: 2011-08-19
    Description: The scaling relations presently derived illustrate the influence of ballistic coefficient and L/D primary vehicle parameters on the peak heating rate and total heating/unit area for gliding entry of the earth atmosphere at parabolic speed. Comparisons with stagnation-point and windward centerline laminar and turbulent heating during three Space Shuttle flights are presented. It is found that total heat input/unit area is reduced by decreasing both of the primary vehicle parameters.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA Journal (ISSN 0001-1452); 24; 2047-204
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  • 37
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    Small satellites (1986)
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    Publication Date: 2011-08-19
    Description: Satellites smaller than Mimas (r = 195 km) are distinguished by irregular overall shapes and by rough limb topography. Material properties and impact cratering dominate the shaping of these objects. Long fragmentation histories can produce a variety of internal structures, but so far there is no direct evidence that any small satellite is an equilibrium ellipsoid made up of noncohesive gravitationally bound rubble. One many bodies that orbit close to their primary the tidal and rotational components of surface gravity strongly affect the directions of local g and thereby affect the redistribution of regolith by mass wasting. Downslope movement of regolith is extensive on Deimos, and is probably effective on many other small satellites. It is shown that in some cases observed patterns of downslope mass wasting cold produce useful constraints on the satellite's mean density. The diversity of features seen in the few high-resolution images of small satellites currently available suggests that these objects have undergone complex histories of cratering, fragmentation, and regolith evolution.
    Keywords: LUNAR AND PLANETARY EXPLORATION
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  • 38
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    Satellites of Uranus and Neptune, and the Pluto-Charon system (1986)
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    Publication Date: 2011-08-19
    Description: The orbital properties, surface compositions, opposition surges, masses, radii, and densities of the satellites of Uranus are presented. It is noted that the Uranian satellites are comparable in size to the largest of Saturn's icy satellites while density measurements suggest that the bulk compositions of Ariel and Umbriel might be different from those of Titania and Oberon. Consideration is given to the two satellites of Neptune and the question of a third satellite is addressed. The elements of Charon, determined from astrometric observations by photographic and speckle interferometric techniques, and then from eclipse observations, are given. The diurnal period of Pluto and its photometric lightcurve are discussed. The similarities and differences existing between the satellites of Uranus and Neptune and the Pluto-Charon pair are mentioned briefly.
    Keywords: LUNAR AND PLANETARY EXPLORATION
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  • 39
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    Interactions of planetary magnetospheres with icy satellite surfaces (1986)
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    Publication Date: 2011-08-19
    Description: When natural satellites and ring particles are embedded within magnetospheric plasmas, the charged particles interact with the surfaces of these solid bodies. These interactions have important implications for the surface, the atmosphere of the parent body, and the magnetosphere as a whole. Significant erosion of the surface by sputtering, as well as redeposition of sputter ejecta, can occur over geologic time. The surface can also be chemically modified. Sputter ejecta can make important contributions to the atmosphere; sputtering provides a lower limit to the atmospheric column density even for arbitrarily cold satellite surfaces. Sputter ejecta escaping from the parent body can form extensive neutral clouds within the magnetosphere. Ionization and dissociation within these neutral clouds can be dominant sources of low-energy plasma. The importance of these processes is discussed for the satellites and magnetospheres of Jupiter, Saturn and Uranus.
    Keywords: LUNAR AND PLANETARY EXPLORATION
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  • 40
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    Some background about satellites (1986)
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    Publication Date: 2011-08-19
    Description: Four tables of planetary and satellite data are presented which list satellite discoveries, planetary parameters, satellite orbits, and satellite physical properties respectively. A scheme for classifying the satellites is provided and it is noted that most known moons fall into three general classes: regular satellites, collisional shards, and irregular satellites. Satellite processes are outlined with attention given to origins, dynamical and thermal evolution, surface processes, and composition and cratering. Background material is provided for each family of satellites.
    Keywords: LUNAR AND PLANETARY EXPLORATION
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  • 41
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    Thermal histories, compositions and internal structures of the moons of the solar system (1986)
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    Publication Date: 2011-08-19
    Description: Thermal evolution models of satellites are discussed with emphasis placed on the fundamental physical processes common to all planetary bodies. A comparison is made between the different evolutionary tracks followed by individual satellites. Consideration is given to the compositions and structures of satellites, heat sources, relevant thermal and mechanical properties of the materials in satellite interiors, and heat transfer mechanisms. Thermal history scenarios are presented for the majority of the satellites of the solar system and these are related to the constraints imposed by surface geology.
    Keywords: LUNAR AND PLANETARY EXPLORATION
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  • 42
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    Origins of satellites (1986)
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    Publication Date: 2011-08-19
    Description: Solar system origin and planetary formation are discussed with emphasis placed on accretion disk dynamics, disk instabilities, giant gaseous protoplanets, condensation, sedimentation, coagulation, planetesimal swarm evolution, giant planet formation, and implications for satellites. Disk formation and the dynamics of a protosatellite disk are considered as well as satellite accretion, impact disruption and ablation, and satellite capture. Possible explanations for each of the satellite systems are offered. It is concluded that satellite formation involves a variety of processes.
    Keywords: LUNAR AND PLANETARY EXPLORATION
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  • 43
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    Early thermal profiles and lithospheric strength of Ganymede from extensional tectonic features (1986)
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    Publication Date: 2011-08-19
    Description: The early thermal profiles and the lithospheric stability and strength of Ganymede are quantitatively determined on the basis of brittle lithosphere thickness estimates derived from the width and spacing of extensional tectonic features, together with lithospheric strength envelopes for ice. Plots of the brittle and ductile yield stress vs. depth for the icy lithosphere of Ganymede exhibit a linear increase in brittle strength with depth to a maximum at the brittle-ductile transition that is followed by an exponential decrease in ductile yield stress with depth. The results obtained imply that the thermal gradient and lithospheric strength have varied laterally by factor as great as 5, and that Ganymede underwent cooling in a highly inhomogeneous fashion with lateral thermal anomalies. The present analysis furnishes reasons for the stability of large cratered terrain remnants.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus (ISSN 0019-1035); 68; 252-265
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  • 44
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    Profiling Saturn's rings by radio occultation (1986)
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    Publication Date: 2011-08-19
    Description: The development of reconstruction algorithms that correct for diffraction effects in radio occultation measurements is described. The reciprocal Fresnel transform relationship between the complex amplitude of the observed coherent signal and the complex microwave transmittance of the rings is derived using the Huygens-Fresnel formulation of the diffraction problem. The effects of the finite data segment width, the uncertainties in the Fresnel scale, systematic phase errors in the kernel of the inverse transform, reference oscillator instabilities, and random noise measurements on the resolution of the reconstructed transmittance are analyzed. Examples of reconstructed opacity profiles for some regions of Saturn's rings derived by applying the reconstruction theory to Voyager 1 at Saturn data are presented.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus (ISSN 0019-1035); 68; 120-166
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  • 45
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    Interannual variability of global dust storms on Mars (1986)
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    Publication Date: 2011-08-19
    Description: Under the assumption that the cross-equatorial Hadley circulation plays a key role in the onset of Martian global dust storms, numerical simulations indicate that a northern hemisphere dust haze weakens its intensity and, thereby, its contribution to the surface stress in the southern hemisphere. Since this in turn reduces the possibility of global dust storm development, the interannual variability observed is the result of either a competition between circulations in opposite hemispheres, in which case the variability has a random component, or it is the result of dust cycling between hemispheres, so that the variability is related to the characteristics of the global dust storms themselves.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science (ISSN 0036-8075); 234; 459-461
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  • 46
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    Affordable solar system exploration (1986)
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    Publication Date: 2011-08-19
    Description: The design features of the Comet Rendezvous Asteroid Flyby (CRAF) version of the Mariner Mark II spacecraft are described, together with the instruments to be carried aboard and the goals of the mission. To minimize the cost, computer-aided design, engineering, and manufacturing will be used, and, where possible, established technologies and off-the- shelf products will be incorporated. Planned for a launch in 1992, the CRAF will rendezvous with the Tempel 2 comet in 1996 and will stick with it through 1999, making studies of plasma in the comet's coma and the comet's dust, gas, and nucleus by means of its penetrator rocket which will pierce the nucleus.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Aerospace America (ISSN 0740-722X); 24; 28-31
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  • 47
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    Magnetic configurations of planetary obstacles (1986)
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    Publication Date: 2011-08-19
    Description: The interaction of the solar wind with planetlike obstacles is examined. The four different types of interactions, and the properties of the planets relative to their roles as obstacles to solar wind flow are discussed. The characteristic features of the magnetosphere of Mercury, Jupiter, Saturn, and the earth are described; particular attention is given to the configuration of the magnetosphere and the factors which control the position and shape of the magnetopause. The role of the magnetic field as it becomes modified in the solar wind interaction with nonmagnetic objects possessing an ionosphere is studied and examples of ionospheric interaction, such as Venusian and Titan interactions, are presented.
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  • 48
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    Solar wind control of Jupiter's decametric radio emission (1986)
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    Publication Date: 2011-08-19
    Description: Observations of the solar wind close to Jupiter are compared with the decametric radio emission (DAM), using data recorded by Voyager 1 and Voyager 2 during 1979. The Non-Io DAM, recorded by both spacecraft and combined using the superposed epoch technique, is found to correlate with the solar wind density and velocity, as well as with the interplanetary magnetic field (IMF) magnitude. In agreement with earlier work using ground-based observations, there are indications that the Non-Io DAM is somehow associated with magnetic sector structure although the precise details of the relationship are still not known and it is not clear if this is a fundamental effect or some secondary effect of intercorrelation.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Astronomy and Astrophysics (ISSN 0004-6361); 165; 1-2,
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  • 49
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    Quadratic resonance in the three-dimensional oscillations of inviscid drops with surface tension (1986)
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    Publication Date: 2011-08-19
    Description: The moderate-amplitude, three-dimensional oscillations of an inviscid drop are described in terms of spherical harmonics. Specific oscillation modes are resonantly coupled by quadratic nonlinearities caused by inertia, capillarity, and drop deformation. The equations describing the interactions of these modes are derived from the variational principle for the appropriate Lagrangian by expressing the modal amplitudes to be functions of a slow time scale and by preaveraging the Lagrangian over the time scale of the primary oscillations. Stochastic motions are predicted for nonaxisymmetric deformations starting from most initial conditions, even those arbitrarily close to the axisymmetric shapes. The stochasticity is characterized by a redistribution of the energy contained in the initial deformation over all the degrees of freedom of the interacting modes.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Physics of Fluids (ISSN 0031-9171); 29; 2788-279
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  • 50
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    Dynamic crystallization of chondrule melts of porphyritic and radial pyroxene composition (1986)
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    Publication Date: 2011-08-19
    Description: Dynamic crystallization experiments in which heterogeneous nucleation is an important variable have been completed on four melts of chondrule composition. Compositions were chosen to best represent chondrules with porphyritic pyroxene and radial pyroxene textures. Experimental results show that heterogeneous nucleation is essential for the formation of porphyritic textures. Without preexisting nuclei, too much supercooling is established before crystallization is initiated and the textures are more likely to be dendritic or radial. In the near total absence of nuclei, radial textures can form at cooling rates as slow as 5 C/hr in this study. By varying the heterogeneous nucleation conditions and having a melt in which the appropriate phases are stable or metastable, analogs to most of the recognized chondrule textures can be produced in a single melt composition.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Geochimica et Cosmochimica Acta (ISSN 0016-7037); 50; 1715-172
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  • 51
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    Evidence for the existence of additional small satellites of Saturn (1986)
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    Publication Date: 2011-08-19
    Description: Voyager-1 and 2 long exposure images were studied in a search for previously undiscovered satellites in the Saturn system. The technique used was to overlap the images with common view areas, thereby including increasingly higher-resolution images of nearby exposures with those taken at greater distances during approach. No definite identifications were made of new satellites. However, five objects were apparently detected by the survey and the orbits associated with each of the recorded photographic 'streaks' were calculated. Techniques are discussed for applying the Space Telescope to confirm or disprove the satellite status of the observed objects.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus (ISSN 0019-1035); 67; 189-204
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    Numerical experiments of axisymmetric flow in a nonuniform gravitational field (1986)
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    Publication Date: 2011-08-19
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA Journal (ISSN 0001-1452); 24; 1483-148
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    Is Navier-Stokes turbulence chaotic? (1986)
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    Publication Date: 2011-08-19
    Description: Whether turbulent solutions of the Navier-Stokes equations are chaotic is considered. Initially neighboring solutions for a low-Reynolds-number fully developed turbulence are compared. The turbulence is sustained by a nonrandom time-independent external force. The solutions separate exponentially with time, having a positive Liapunov characteristic exponent. Thus the turbulence is characterized as chaotic.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Physics of Fluids (ISSN 0031-9171); 29; 1453-145
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    A theoretical model for the annular jet instability (1986)
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    Publication Date: 2011-08-19
    Description: The instability of an annular gas-core liquid jet is modeled theoretically by treating the liquid layer as a membrane moving under the influences of its own inertia, surface tension, and the gaseous hydrostatic pressure difference between its two sides. Essential physical mechanisms are reconstructed without making any attempt to fit experimental data with model constants. The results compare favorably with those of experiment.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Physics of Fluids (ISSN 0031-9171); 29; 2076-208
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    Experiments on annular liquid jet instability and on the formation of liquid shells (1986)
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    Publication Date: 2011-08-19
    Description: An annular jet flow of liquid surrounding a flow of gas at its core is extremely unstable. Experiments are described in which such a flow is generated by an annular nozzle operated at fairly specific conditions. It is shown that periodic, axisymmetric oscillations arise spontaneously within the cylindrical sheet emerging from the nozzle and grow with such rapidity along the axial dimension that a sealing-off and encapsulation of the core gas occurs within a few jet diameters. This is closely followed by a pinchoff of the liquid between adjacent bubbles. The liquid shells set free thereby assume spherically symmetric form under capillary forces, and each contains a precisely uniform measure of gas and of liquid on account of the extremely high frequency-stability of the process. Description is given of the fluid dynamic processes by which the shells are formed, and mention is made of exploiting the instability for the production of rigid shells for technological applications.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Physics of Fluids (ISSN 0031-9171); 29; 2086-209
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    The rotation period of Uranus (1986)
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    Publication Date: 2011-08-19
    Description: On 24 January 1986 the spacecraft Voyager 2 transversed the innermost magnetosphere of the planet Uranus, coming as close as 4.2 Uranus radii to the planet. It is pointed out that the magnetic field data provide a direct measure of the rotation period of the planet's interior, where the field is generated. Two period determinations are reported. A combination of the obtained values provides a weighted mean value of P = 17.24 + or - 0.01 h. It is concluded that the 17.24-h rotation period has important consequences for studies of atmospheric dynamics and the internal structure and composition of Uranus. Thus, inferences regarding the internal structure can be drawn from the relationship between the observed planetary oblateness, rotation period, and gravitational moment.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Nature (ISSN 0028-0836); 322; 42
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    Martian volatiles in shergottite EETA 79001 - New evidence from oxidized sulfur and sulfur-rich aluminosilicates (1986)
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    Publication Date: 2011-08-19
    Description: Two equivalent chips of lithology A (lith-A) and lithology C (lith-C) taken from the same interior portion of EETA 79001 shergottite have been analyzed for volatile species produced by high-vacuum pyrolysis. The lith-C was found to contain an oxidized sulfur component that does not occur in lith-A. The preterrestrial origin of this component in lith-C is supported by the occurrence in lith-C of sulfur- and chlorine-rich aluminosilicates that are not the same as Antarctic weathering products found in the control samples. The oxidation state and distribution of sulfur found in lith-C are consistent with the interpretation of EETA 79001 as a rock from Mars.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Geochimica et Cosmochimica Acta (ISSN 0016-7037); 50; 1049-105
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    Nuclear tracks, Sm isotopes and neutron capture effects in the Elephant Morraine shergottite (1986)
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    Publication Date: 2011-08-19
    Description: Nuclear track studies, uranium concentration measurements and Sm-isotope studies have been performed on both lithologies A and B of the Elephant Morraine shergottite, EETA 79001. Track studies show that EETA 79001 was a rather small object in space with a preatmospheric radius of 12 + or - 2 cm, corresponding to a preatmospheric mass of 28 + or - 13 kg. Phosphates have U concentrations ranging from 0.3 to 1.3 ppm. There are occasional phosphates with excess fission tracks, possibly produced from neutron-induced fission of U and Th, during the regolith exposure in the shergottite parent body (SPB). Sm-isotope studies, while not showing any clear-cut excess in Sm-150, make it possible to derive meaningful upper limits to thermal neutron fluences of 2 to 3 x 10 to the 15th n/sq cm, during a possible regolith irradiation. These limits are consistent with the track data and also make it possible to derive an upper limit to the neutron exposure age of EETA 79001 of 55 Myr in the SPB regolith.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Geochimica et Cosmochimica Acta (ISSN 0016-7037); 50; 1039-104
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    Clinopyroxene REE distribution coefficients for shergottites The REE content of the Shergotty melt (1986)
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    Publication Date: 2011-08-19
    Description: Rare-earth element (REE) distribution coefficients were measured between synthetic pyroxenes and melts similar in composition to the Shergotty intercumulus fluid. REE-doped synthetic glass samples were analyzed by means of an automated microbeam electron microprobe. The coefficients were found to exhibit a strong positive correlation with pyroxene wollastonite content. Using distribution coefficients measured for the natural phase compositions, REE abundances for the Shergotty intercumulus melt were computed.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Geochimica et Cosmochimica Acta (ISSN 0016-7037); 50; 927-937
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    X-ray investigations related to the shock history of the Shergotty achondrite (1986)
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    Publication Date: 2011-08-19
    Description: The shock stress suffered by naturally shocked materials from the Shergotty achondrite was studied using X-ray diffraction techniques and experimentally shocked augite and enstatite as standards. The Shergotty pyroxenes revealed the formation of continuous diffraction rings, line broadening, preferred orientation of small scale diffraction domains, and other evidence of substantial lattice disorders. As disclosed by the application of Debye-Scherrer techniques, they are hybrids between single crystals and fine-grained random powders. The pyroxene lattice is very resistant to shock damage on smaller scales. While measurable lattice disaggregation and progressive fragmentation occur below 25 GPa, little additional damage is suffered from application of pressures between 30 to 60 GPa, making pressure calibration of naturally shocked pyroxenes via X-ray methods difficult. Powder diffractometer scans on pure maskelynite fractions of Shergotty revealed small amounts of still coherently diffracting plagioclase, which may contribute to the high refractive indices of the diaplectic feldspar glasses of Shergotty.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Geochimica et Cosmochimica Acta (ISSN 0016-7037); 50; 905-908
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    Turbulent Reynolds analogy factors of stacked large-eddy breakup devices (1986)
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    Publication Date: 2011-08-19
    Description: Direct measurements are made of turbulent Reynolds analogy factors, referenced to a flat plate, for turbulent boundary layer flows altered by stacked arrays of large eddy breakup devices (LEBUs). These are of interest as drag reducers when inserted into a boundary layer transverse to the flow. The data thus obtained furnish evidence that heat transfer, skin friction drag, and LEBU performance factors in low Reynolds number flows are sensitive to flow history. Attention is given to the apparatus and measurement procedures used.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Spacecraft and Rockets (ISSN 0022-4650); 23; 348-350
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    Coupling conditions for integrating boundary layer and rotational inviscid flow (1986)
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    Publication Date: 2011-08-19
    Description: The matching of a boundary layer and a rotational inviscid flow is reexamined by extending the Johnson and Sockol (1979) coupling conditions to include the case where the boundary layer solution includes the second-order effects of the freestream vorticity and the total temperature gradient. It is pointed out that two of the three conditions are not independent. If the boundary layer solution satisfies the appropriate momentum and energy integral equations, it follows that the imposition of the normal mass flux condition insures that the conditions on a normal flux of streamwise momentum and total enthalpy will also be satisfied.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA Journal (ISSN 0001-1452); 24; 1033-103
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    A new approach for solving the three-dimensional steady Euler equations. I - General theory (1986)
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    Publication Date: 2011-08-19
    Description: The present iterative procedure combines the Clebsch potentials and the Munk-Prim (1947) substitution principle with an extension of a semidirect Cauchy-Riemann solver to three dimensions, in order to solve steady, inviscid three-dimensional rotational flow problems in either subsonic or incompressible flow regimes. This solution procedure can be used, upon discretization, to obtain inviscid subsonic flow solutions in a 180-deg turning channel. In addition to accurately predicting the behavior of weak secondary flows, the algorithm can generate solutions for strong secondary flows and will yield acceptable flow solutions after only 10-20 outer loop iterations.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Computational Physics (ISSN 0021-9991); 60; 23-61
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    Catching the whispers from Uranus (1986)
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    Publication Date: 2011-08-19
    Description: Sophisticated telecommunications techniques are described that were used to acquire images of Uranus, its 14 moons and ten narrow rings darker than coal. The images, equal in quality to those transmitted from Saturn several years earlier despite the signal being weaker by 6 dB due to the increased distance, were received from Voyager 2 during its January 24, 1986 flyby of Uranus. Solutions to the problem of the weakening signal were found in modifications to Voyager's image processing system and NASA's ground tracking network. In April 1985, Voyager's prime flight data computer was reconfigured to accept only nonimaging science data, and its backup, only imaging data; the latter was reprogrammed to determine only arithmetic differences between adjacent pixel intensities rather than absolute intensities. By image compression, equivalent imaging information could be sent at lower bit rates. Instead of Golay coding, Reed-Solomon onboard encoding was used. These techniques gained the equivalent of 4-dB in imaging yield. Additional improvements were gained by using earth station antennas in pairs (the Parkes radio telescope and the Canberra ground station antenna). Moves under way to prepare for the Voyager encounter with Neptune in 1989 are described (using additional antennas and arrays, scaling up the Deep Space Network antennas from 64 m to 70 m, etc.) to assure almost Saturn-equivalent pictures despite a further 3.5-dB drop in signal strength.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Aerospace America (ISSN 0740-722X); 24; 44-46
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    Numerical analysis of confined recirculating gas-solid turbulent flows (1986)
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    Publication Date: 2011-08-19
    Description: Particle dispersion in confined recirculating turbulent flows has been investigated numerically. The present computational scheme utilizes Eulerian forms of the governing equations and allows two-way coupling between gas and solid phases. A recently developed two-phase closure model based on the multiple-scale turbulence model was used for the estimation of turbulent viscosities and diffusivities. For the particle size and loading considered in this study, the effect of particulate phase on the conveying gas is small, the nonequilibrium between the two phases is significant. Effects of recirculation, expanded chamber size and secondary annular jet momentum on the particle mixing rate are also investigated. In general, the present numerical results are in reasonably good agreement with the available experimental data.
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    Motions in the interiors and atmospheres of Jupiter and Saturn. II - Barotropic instabilities and normal modes of an adiabatic planet (1986)
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    Publication Date: 2011-08-19
    Description: A rotating and adiabatic inviscid fluid planet possesses low frequency motions that are barotropic, quasi-geostrophic and quasi-columnar. The limiting curvature at which flow becomes unstable upon projection onto the planetary surface is negative, with an amplitude that is 3-4 times that for thin atmospheres, in planets in which density linearly decreases to zero at the surface. This result is shown to hold for all quasi-columnar perturbations. Both the phase speed of the normal mode oscillations and the barotropic stability criterion have features in common with Saturn and Jupiter oscillations.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus (ISSN 0019-1035); 65; 370-382
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    The climate of Mars (1986)
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    Publication Date: 2011-08-19
    Description: The composition of the primitive Martian atmosphere and its development into the present environment are described. The primitive atmosphere consisted of water vapor, carbon dioxide, and nitrogen released from rocks; the greenhouse effect which maintained the surface temperature above the frost point of water is examined. Volcanic activity reduced the greenhouse effect and along with CO2 removal from the atmosphere caused a lowering of the planet temperature. The global circulation patterns on earth and Mars are compared; the similarities in the circulation patterns and Mars' seasonal variations are studied. The carbon dioxide and water cycles on Mars are analyzed; the carbon dioxide cycle determines seasonal variations in surface pressure and the behavior of the water cycle. The behavior of the atmospheric dust and the relationship between the seasonal dust cycle and Hadley circulation are investigated. The periodic variations in the three orbital parameters of Mars, which affect the climate by changing the seasonal and latitudinal distribution of incoming solar energy are discussed
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Scientific American (ISSN 0036-8733); 254; 54-62
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    Implications of the VEGA balloon results for Venus atmospheric dynamics (1986)
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    Publication Date: 2011-08-19
    Description: Both VEGA balloons encountered vertical winds with typical velocities of 1 to 2 meters per second. These values are consistent with those estimated from mixing length theory of thermal convection. However, small-scale temperature fluctuations for each balloon were sometimes larger than predicted. The approximate 6.5-kelvin difference in temperature consistently seen between VEGA-1 and VEGA-2 is probably due to synoptic or planetary-scale nonaxisymmetric disturbances that propagate westward with respect to the planet. There is also evidence from Doppler data for the existence of solar-fixed nonaxisymmetric motions that may be thermal tides. Surface topography may influence atmospheric motions experienced by the VEGA-2 balloon.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science (ISSN 0036-8075); 231; 1422-142
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    Overview of VEGA Venus balloon in situ meteorological measurements (1986)
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    Publication Date: 2011-08-19
    Description: The VEGA balloons made in situ measurements of pressure, temperature, vertical wind velocity, ambient light, frequency of lightning, and cloud particle backscatter. Both balloons encountered highly variable atmospheric conditions, with periods of intense vertical winds occurring sporadically throughout their flights. Downward winds as large as 3.5 meters per second occasionally forced the balloons to descend as much as 2.5 kilometers below their equilibrium float altitudes. Large variations in pressure, temperature, ambient light level, and cloud particle backscatter (VEGA-1 only) correlated well during these excursions, indicating that these properties were strong functions of altitude in those parts of the middle cloud layer sampled by the balloons.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science (ISSN 0036-8075); 231; 1411-141
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    Atmospheres and ionospheres of the outer planets and their satellites (1986)
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    Publication Date: 2011-08-19
    Description: Essential aspects of physical and chemical processes in the atmospheres and ionospheres of the outer planets are examined in an introductory overview of current knowledge, intended both for graduate students of planetary science and for practicing scientists. Chapters are devoted to bulk atmospheric compositions, thermal structures, cloud structures, vertical mixing, photochemistry, the ionospheres, and the satellites. Measurement data are compiled in tables, and extensive graphs and diagrams are provided.
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    Two-phase flows and heat transfer within systems with ambient pressure above the thermodynamic critical pressure (1986)
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    Publication Date: 2011-08-19
    Description: In systems where the design inlet and outlet pressure P sub amb are maintained above the thermodynamic critical pressure P sub c, it is often assumed that heat and mass transfer are governed by single-phase relations and that two-phase flows cannot occur. This simple rule of thumb is adequate in many low-power designs but is inadequate for high-performance turbomachines, boilers, and other systems where two-phase regions can exist even though P sub amb P sub c. Heat and mass transfer and rotordynamic-fluid-mechanic restoring forces depend on momentum differences, and those for a two-phase zone can differ significantly from those for a single-phase zone. By using a laminar, variable-property bearing code and a rotating boiler code, pressure and temperature surfaces were determined that illustrate nesting of a two-phase region within a supercritical pressure region. The method of corresponding states is applied to bearings with reasonable rapport.
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    Forced convection heat transfer to air/water vapor mixtures (1986)
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    Publication Date: 2011-08-19
    Description: Heat transfer coefficients were measured using both dry air and air/water vapor mixtures in the same forced convection cooling test rig (jet array impingement configurations) with mass ratios of water vapor to air up to 0.23. The primary objective was to verify by direct experiment that selected existing methods for evaluation of viscosity and thermal conductivity of air/water vapor mixtures could be used with confidence to predict heat transfer coefficients for such mixtures using as a basis heat transfer data for dry air only. The property evaluation methods deemed most appropriate require as a basis a measured property value at one mixture composition in addition to the property values for the pure components.
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    Implicit solution methods in computational fluid dynamics (1986)
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    Publication Date: 2011-08-19
    Description: A class of implicit finite difference schemes of the Beam and Warming approximate factorization type will be addressed. The development and analysis of various aspects of this class of schemes will be given along with the motivations behind many of the choices. Various acceleration and efficiency modifications such as matrix reduction, diagonalization and flux split schemes will be presented. The methods are demonstrated in fully vectorized codes for a CRAY type architecture. The emphasis will be on the Euler equations in generalized coordinates.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Applied Numerical Mathematics (ISSN 0168-9274); 2; 441-474
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    Distribution of resistive body-force in curved free-surface flow (1986)
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    Publication Date: 2011-08-19
    Description: The customary procedure for including resistive effects in turbulent hydraulic and stratified atmospheric flows is to integrate the empirically-known boundary shears over the entire wetted boundary of a thin fluid slab. A resistive body-force is then assumed to exist everywhere in each slab to replace the boundary shearing force. For the classical Saint-Venant (1871) model, this body-force can be shown to have a constant distribution in the vertical direction, and therefore can be evaluated for use in the momentum differential equation. In the newer Dressler theory (1978), however, for unsteady flow over curved beds, it is proved here that a constant body-force distribution is not possible. Its variable distribution is determined as well as its magnitude for use in the curved-flow equations. This variable distribution acts to produce an equal resultant in every thin layer of fluid parallel to the bed in an angular wedge over the curved channel bed. The new curved-flow equations are therefore extended to include resistive effects.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Mathematical Methods in the Applied Sciences (ISSN 0170-4214); 8; 4, 19; 492-501
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    Mass fractionation during transonic escape and implications for loss of water from Mars and Venus (1986)
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    Publication Date: 2011-08-19
    Description: Hydrodynamic escape of hydrogen from a planetary atmosphere can remove heavier gases as well as hydrogen, provided that the escape rate is sufficiently large. Analytic approximations for the degree of mass fractionation of a trace species during hydrodynamic escape are compared with accurate numerical solutions for the case of transonic outflow. The analytic approximations are most accurate when the ratio of molecular weights of the heavier and lighter constituents is large so that nonlinear terms in the momentum equation for the heavy constituent become small. The simplest analytic formula is readily generalized to the case where a heavy constituent is also a major species. Application of the generalized formula to hypothetical episodes of hydrodynamic escape from Venus and Mars suggests that both hydrogen and oxygen could have escaped; thus, substantial quantities of water may have been lost without the need to oxidize large amounts of the crust.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus (ISSN 0019-1035); 68; 462-480
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    Numerical study of sink-flow boundary layers (1986)
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    Publication Date: 2011-08-19
    Description: Direct numerical simulations of sink-flow boundary layers, with acceleration parameters K between 1.5 x 10 to the -6th and 3.0 x 10 to the -6th, are presented. The three-dimensional, time-dependent Navier-Stokes equations are solved numerically, using a spectral method, with about one million degrees of freedom. The flow is assumed to be statistically steady, and self-similar. A multiple-scale approximation and periodic conditions are applied to the fluctuations. The turbulence is studied using instantaneous and statistical results. Good agreement with the experiments of Jones and Launder (1972) is observed. The two effects of the favorable pressure gradient are to extend the logarithmic layer, and to alter the energy balance of the turbulence near the edge of the boundary layer. At low Reynolds number the logarithmic layer is shortened and slightly displaced, but wall-layer streaks are present even at the lowest values of R(theta) for which turbulence can be sustained. Large quiescent patches appear in the flow. Relaminarization occurs at K = 3.0 x 10 to the -6th, corresponding to a Reynolds number R(theta) of about 330.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Fluid Mechanics (ISSN 0022-1120); 172; 307-328
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    Europa (1986)
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    Publication Date: 2011-08-19
    Description: Europa, the second major satellite outward from Jupiter, is a lunar-sized object in synchronous rotation about that planet. Its high albedo and spectral characteristics indicate the presence of surface water ice and/or frost. Its density suggests a substantial silicate component of at least 85 percent by volume. A limited variety of landforms is seen in Voyager images, most likely because of poor spatial resolution of these data. The absence of numerous impact craters is interpreted as indicating a youthful surface and /or surface regenerating processes. A planet-wide lineament system has been interpreted to result from tectonic stresses induced by evolution of Europa's orbit and interior. Present data do not permit unambiguous tests of such interpretations. Greater insight may come from analytical or numerical models and future spacecraft observations.
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    Cratering of planetary satellites (1986)
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    Publication Date: 2011-08-19
    Description: Recent findings concerning craters and cratering populations on the satellites of Jupiter and Saturn are discussed. Current understanding of cratering mechanics is reviewed with emphasis placed on scaling and ejecta and the differences between cratering in rock and ice. Evidence from crater statistics regarding cratering histories on various planetary satellites is discussed and connections are made with what is known about the cratering record on the terrestrial bodies. Consideration is given to the source populations and an attempt is made to summarize and critique the various scenarios that have been proposed for linking the cratering records on the various planets and satellites. It is noted that early Voyager Uranus results seem compatible with the present summary.
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    The Jovian magnetotail (1986)
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    Publication Date: 2011-08-19
    Description: The current understanding of the plasma, magnetic field, and plasma wave characteristics of the near and distant Jovian magnetotail is discussed. The properties of these two regions are compared, with particular emphasis given to the data on the distant tail obtained by Voyager 2. The Jovian tail has many unusual properties, such as the large scale sausage-string shape of its outer boundary, but some of its properties resemble those of the earth's magnetotail, such as its central current sheet and a surrounding region resembling a plasma sheet consisting of hot ions. Data are presented that support the view that plasma in the Jovian tail plasma sheet comes from Jupiter.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Advances in Space Research (ISSN 0273-1177); 6; 1, 19
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    On the possibility of diffusionally driven oscillations in two component gas bubbles in fluids (1986)
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    Publication Date: 2011-08-19
    Description: The problem of an isolated, stationary, two-component gas bubble in a fluid is analyzed. The appropriate governing equations, and an approximate version of these equations, for this model system are reviewed. The qualitative differences in bubble dissolution behavior between single- and two-component gas bubbles are elucidated. In particular, it is demonstrated that in the latter case the gas bubble radius may exhibit extrema as a function of time for certain values of the controlling parameters. The conditions under which these extrema may occur, and the maximum number of extrema which are permitted are elucidated.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Chemical Engineering Science (ISSN 0009-2509); 41; 9, 19; 2333-234
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  • 81
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    Oscillations of a viscous compound drop (1986)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The effect of viscosity on normal mode oscillations of a compound drop is determined for a range of values of the viscosity, and the effect of a host medium is considered. The general form of the dispersion relation is derived, and numerical values are obtained for the case of an annular liquid region composed of silicon oil and with the core and host regions taken to be air. Results indicate that the sloshing mode of the compound drop is more damped than the bubble mode.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Physics of Fluids (ISSN 0031-9171); 29; 3481-348
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  • 82
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    Radar glory from buried craters on icy moons (1986)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Three ice-covered moons of Jupiter, in comparison with rocky planets and earth's moon, produce radar echoes of astounding strengths and bizarre polarizations. Scattering from buried craters can explain these and other anomalous properties of the echoes. The role of such craters is analogous to that of the water droplets that create the apparition known as 'the glory', the optically bright region surrounding an observer's shadow on a cloud. Both situations involve the electromagnetic phenomenon of total internal reflection at a dielectric interface, operating in a geometry that strongly favors exact backscattering. Dim surface craters are transformed into bright glory holes by being buried under somewhat denser material, thereby increasing the intensity of their echoes by factors of hundreds. The dielectric interface thus formed at the crater walls nicely accounts for the unusual polarizations of the echoes.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science (ISSN 0036-8075); 234; 587-590
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  • 83
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    The binary fission origin of the moon (1986)
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    Publication Date: 2011-08-19
    Description: The major arguments for and against the binary fission model of lunar origin are reviewed. Unresolved problems include: (1) how the protoearth acquired sufficient angular velocity to fission, and (2) how the earth-moon system lost its excess angular momentum after fission. Despite these uncertainties, the compositional similarities between the earth's mantle and the bulk moon suggest that the fission model is worth considering. The proposed sequence of events in the formation of the moon by binary fission is given.
    Keywords: LUNAR AND PLANETARY EXPLORATION
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  • 84
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    The centrifugal flute instability and the generation of Saturnian kilometric radiation (1986)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: It is shown that the source region for Saturnian kilometric radiation which originates in the high latitude near-noon dayside ionosphere can be mapped via the Saturn magnetic field to the outer edge of the dayside equatorial plasma sheet. It is shown how the MHD waves observed at the outer boundary of the plasma sheet may be causally related to the field-aligned acceleration of electrons to keV energies. It is suggested that the strong emission peak at a fixed Saturnian longitude is a consequence of locally reduced electron plasma frequency to electron gyrofrequency ratio.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research (ISSN 0148-0227); 91; 10989-10
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  • 85
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    Magnetostrophic balance in planetary dynamos - Predictions for Neptune's magnetosphere (1986)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: With the purpose of estimating Neptune's magnetic field and its implications for nonthermal Neptune radio emissions, a new scaling law for planetary magnetic fields was developed in terms of externally observable parameters (the planet's mean density, radius, mass, rotation rate, and internal heat source luminosity). From a comparison of theory and observations by Voyager it was concluded that planetary dynamos are two-state systems with either zero intrinsic magnetic field (for planets with low internal heat source) or (for planets with the internal heat source sufficiently strong to drive convection) a magnetic field near the upper bound determined from magnetostrophic balance. It is noted that mass loading of the Neptune magnetosphere by Triton may play an important role in the generation of nonthermal radio emissions.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research (ISSN 0148-0227); 91; 11003-11
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  • 86
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    Implications of preliminary Vega balloon results for the Venus atmosphere dynamics (1986)
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    Publication Date: 2011-08-19
    Description: The typical 1-2 m/sec vertical winds encountered by the Vega balloons probably result from thermal convection. The consistent 6.5-kelvin differential between the Vega 1 and Vega 2 temperatures is attributable to disturbances of synoptic or planetary scale. According to the Doppler tracking the winds were stronger than on earlier missions, perhaps because of solar thermal tides. The motions of Vega 2 may have been affected by waves from mountainous terrain.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Soviet Astronomy Letters (ISSN 0360-0327); 12; 22-25
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  • 87
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    Mean zonal winds on Venus from Doppler tracking of the Vega balloons (1986)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Doppler measurements of the two Vega balloons yield the following provisional estimates for the mean zonal wind velocity at the 53-54 km level in the Venus atmosphere: 69 + or - 1 m/sec for Vega 1 and 66 + or - 1 m/sec for Vega 2, with westward flow. The wind data show a perturbation which might be an evidence of solar tides.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Soviet Astronomy Letters (ISSN 0360-0327); 12; 17-19
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  • 88
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    Small-scale turbulence in the Venus middle cloud layer (1986)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Measurements of the Doppler-velocity fluctuations indicated by the radio signals from the Vega balloons testify to strong turbulence in the nightside as well as the dayside Venus cloud layer. Wind speeds vary by up to 2 m/sec on time scales of 30-100 sec.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Soviet Astronomy Letters (ISSN 0360-0327); 12; 20-22
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  • 89
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    Thermal structure in the Venus middle cloud layer (1986)
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    Publication Date: 2011-08-19
    Description: Thermal structure measurements obtained by the two Vega balloons show the Venus atmosphere in the middle cloud layer to be near-adiabatic, on the whole; but discrete air masses are present that differ slightly from one another in potential temperature and entropy. The Vega 1 temperatures are 6.5 K warmer than measured by Vega 2 at given pressures. Measurements taken by the Vega 2 lander on descent through these levels agree with the Vega 2 balloon data.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Soviet Astronomy Letters (ISSN 0360-0327); 12; 15-17
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  • 90
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    The Vega balloon experiment - Initial results from the global radio tracking (1986)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A unique global array of 20 radio telescopes provided 24-h telemetry acquisition of meteorological data from the Vega balloons and differential VLBI measurements of their trajectories. Initial Doppler-tracking analysis indicates mean zonal wind velocities of 69 + or - 1 and 66 + or - 1 m/sec at the Vega 1 and Vega 2 float heights, and discloses an anomaly in the Vega 2 trajectory above the mountains in Aphrodite Terra.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Soviet Astronomy Letters (ISSN 0360-0327); 12; 10-12
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  • 91
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    Meteorological data along the Vega 1, 2 float paths (1986)
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    Publication Date: 2011-08-19
    Description: The Vega balloons transmitted in situ measurements of pressure, temperature, vertical wind velocity relative to the balloon craft, cloud-particle backscatter coefficient, and ambient light level in the Venus middle cloud layer. Doppler tracking has yielded estimates for the velocities of atmospheric motion.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Soviet Astronomy Letters (ISSN 0360-0327); 12; 12-15
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  • 92
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    The Vega balloon experiments (1986)
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    Publication Date: 2011-08-19
    Description: The goals of the Vega-1 and -2 experiments were to trace the large- and small-scale motions, measure the turbulent heat and momentum flow in the cloud layer, and determine the physical parameters of the Venus atmosphere. The arrangement of the balloon-probe payload, the balloon-deployment sequence, and the balloon flight paths are described. The balloons drifted latitudinally in the Venus atmosphere about one-third the way around the planet at a height of 53-54 km and speeds close to 67 m/sec. The balloon-probe signals, recorded on earth by radio telescopes of ten countries, are being processed.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Soviet Astronomy Letters (ISSN 0360-0327); 12; 3-5
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  • 93
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    Planetesimal dissolution in the envelopes of the forming, giant planets (1986)
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    Publication Date: 2011-08-19
    Description: An evaluation is made of the capacity of planetesimals to penetrate the envelopes of giant planets during their growth phase, by means of a core instability mechanism in which the growing core becomes gradually more adept in the gravitational concentration of gas from its solar nebula environment, until a runaway gas accretion occurs. If most of the accreted mass is contained in planetesimals larger that about 1 km, the critical core mass for runaway accretion will not significantly change when planetesimal dissolution is taken into account; it is accordingly suggested that giant planet envelopes should contain above-solar proportions of virtually all elements, relative to hydrogen.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus (ISSN 0019-1035); 67; 409-443
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  • 94
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    Multiple-scale turbulence model in confined swirling jet predictions (1986)
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    Publication Date: 2011-08-19
    Description: A recently developed multiple-scale turbulence model which attempts to circumvent the deficiencies of earlier models by taking nonequilibrium spectral energy transfer into account is presented. The model's validity is tested by predicting the confined swirling coaxial jet flow in a sudden expansion. It is noted that, in order to account for anisotropic turbulence, a full Reynolds stress model is required.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA Journal (ISSN 0001-1452); 24; 1717-171
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  • 95
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    Modeling of transition and surface roughness effects in boundary-layer flows (1986)
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    Publication Date: 2011-08-19
    Description: Experiments were carried out to examine the influence of three-dimensional, stochastic roughness on the growth of incompressible turbulent boundary layers, as well as the effect of streamwise pressure gradients and freestream turbulence intensity on smooth-wall boundary-layer transition. The modeling of these effects in a two-dimensional boundary-layer computation program was examined with the help of the experiments. A model for surface roughness was developed that relates directly measurable statistical parameters quantifying the roughness geometry to the aerodynamic effects. This model should be valid for a limited class of surfaces found on turbomachinery blading and in other engineering applications. Commonly used criteria for the transition onset performed poorly and presumably need to be modified to account for other factors influencing the process.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA Journal (ISSN 0001-1452); 24; 1642-164
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  • 96
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    Planetary surface weathering (1986)
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    Publication Date: 2011-08-19
    Description: The weathering of planetary surfaces is treated. Both physical and chemical weathering (reactions between minerals or mineraloids and planetary volatiles through oxidation, hydration, carbonation, or solution processes) are discussed. Venus, earth, and Mars all possess permanent atmospheres such that weathering should be expected to significantly affect their respective surfaces. In contrast, Mercury and the moon lack permanent atmospheres but conceivably could experience surface weathering in response to transient atmospheres generated by volcanic or impact cratering events. Weathering processes can be postulated for other rocky objects including Io, Titan, asteroids, and comets.
    Keywords: LUNAR AND PLANETARY EXPLORATION
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  • 97
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    Large volume water sprays for dispersing warm fogs (1986)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A new method for dispersing of warm fogs which impede visibility and alter schedules is described. The method uses large volume recycled water sprays to create curtains of falling drops through which the fog is processed by the ambient wind and spray-induced air flow; the fog droplets are removed by coalescence/rainout. The efficiency of this fog droplet removal process depends on the size spectra of the spray drops and optimum spray drop size is calculated as between 0.3-1.0 mm in diameter. Water spray tests were conducted in order to determine the drop size spectra and temperature response of sprays produced by commercially available fire-fighting nozzles, and nozzle array tests were utilized to study air flow patterns and the thermal properties of the overall system. The initial test data reveal that the fog-dispersal procedure is effective.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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  • 98
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    Liquid fuel spray processes in high-pressure gas flow (1986)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Atomization of single liquid jets injected downstream in high pressure and high velocity airflow was investigated to determine the effect of airstream pressure on mean drop size as measured with a scanning radiometer. For aerodynamic - wave breakup of liquid jets, the ratio of orifice diameter D sub o to measured mean drop diameter D sub m which is assumed equal to D sub 32 or Sauter mean diameter, was correlated with the product of the Weber and Reynolds numbers WeRe and the dimensionless group G1/square root of c, where G is the gravitational acceleration, 1 the mean free molecular path, and square root of C the root mean square velocity, as follows; D sub o/D sub 32 = 1.2 (WeRe) to the 0.4 (G1/square root of c) to the 0.15 for values of WeRe 1 million and an airstream pressure range of 0.10 to 2.10 MPa.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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  • 99
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    Magnetic connection for Saturn's rings and atmosphere (1986)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Latitudinal variations in images of Saturn's disk, upper atmospheric temperatures, and ionospheric electron densities are found in magnetic conjugacy with features in Saturn's ring plane. It is proposed that these latitudinal variations are the result of a variable influx of water transported along magnetic field lines from sources in Saturn's ring plane. These features are thus the surface expression of an electromagnetic erosion mechanism which transports water (in the form of high charge-to-mass ratio particles) from the rings to the atmosphere.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Geophysical Research Letters (ISSN 0094-8276); 13; 773-776
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  • 100
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    Application of the method of lines for solution of the Navier-Stokes equations using nonuniform grid distributions (1986)
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    Publication Date: 2011-08-19
    Description: The method of lines is investigated for the numerical solution of the stream function and velocity form of the Navier-Stokes equations on nonuniform grids. Stiffness characteristics of a linear one-dimensional model equation are examined to establish the feasibility of applying the method to the volicity equation in two dimensions. It is observed that the transformed governing equations in computational domain become stiffer with increasing the number of grid points and the differencing technique affects the stiffness characteristics. The results demonstrate that the method of lines under certain circumstances is highly suitable for the numerical solution of physical problems on domains covered with variable grids.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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