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  • ASTROPHYSICS  (1,141)
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  • ENERGY PRODUCTION AND CONVERSION  (735)
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  • 1
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    In:  CASI
    Publication Date: 2006-06-18
    Description: A discussion is presented on nickel cadmium battery life tests using reconditioning and some comparative tests not using reconditioning. The discussion is aimed at the program application part of the testing. The goals of the program were to get an increased utilization out of the battery system in geosynchronous orbit. An attempt was made to push the depth of discharge operation up around 80 to 85 percent and the intent with the reconditioning program was to extend this type of utilization out towards a 10-year life and attune the voltage regulation.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 259-270
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  • 2
    Publication Date: 2006-06-15
    Description: The mode of operation that is of interest in this discussion is a solar array battery load-sharing mode. The battery is loaded for a fraction of a second and then charged, so the cycle is a 100 millisecond load, followed by a 500 millisecond charge. The purpose of the experiment was to evaluate the charge efficiency and the state of charge. Charge/discharge ratio graphs are presented.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 213-218
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  • 3
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    In:  CASI
    Publication Date: 2006-06-15
    Description: The use of statistical analysis (regression analysis) to determine the data correlation between eight voltage parameters is discussed. The eight parameters correlated include: temperature, depth of discharge; charge rate; discharge rate; percent recharge; concentration of KOH; amount of KOH; and precharge. Graphs are presented which show: (1) starpoint/centerpoint cycles to failure vs. parameters; (2) cycles to failure vs. temperature; and (3) positive and negative plate thickness and weight vs. cycles. An empirical equation derived from cycles to failure vs. temperature graph for cells cycled at 1C charge, 2C discharge, and 14 percent recharge is also presented.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 155-172
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  • 4
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    In:  CASI
    Publication Date: 2006-06-14
    Description: As part of the NASA lightweight battery program, the Lewis Research Center has a number of programs that are being reviewed. A brief and general discussion of these programs is presented.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 133-136
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  • 5
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    In:  CASI
    Publication Date: 2006-06-18
    Description: After using all the instrumentation that is available on a nickel hydrogen battery it will be subjected to the same low earth orbit cycles experienced by the sixty amphere hour nickel cadmium batteries now being flown on some low earth orbit missions. The objective of the test is to demonstrate real differences between the two batteries. In order to simulate flight conditions, the thermal environment and criteria for charge control will vary. The depth of discharge will be increased and testing will continue until some failures or some degradation or spread between cell performances are revealed. Different charge control modes are being considered in order to demonstrate a reasonable life for the nickel hydrogen battery.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 517
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  • 6
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    In:  CASI
    Publication Date: 2006-06-18
    Description: An experiment to obtain some flight experience with a nickel-hydrogen battery in low earth orbit is described. The battery was built to be as compatible with the satellite bus as possible because the satellite bus is used for recharge power. The battery is mounted on an experimental pallet on the satellite. It has its own charge control system, a modification of an existing system that is used for nickel-cadmium, which primarily uses temperature compensated voltage as its criteria. Also, on the pallet is a load bank, a resistive load band, which allows switch to various load regimes. There is some other equipment on the satellite such as the nickel-hydrogen battery to power it. Monitors attached to the 21-cell battery are described.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 499-516
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  • 7
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    In:  CASI
    Publication Date: 2006-06-18
    Description: Features of the first operational nickel hydrogen battery are described as well as experiences encountered during its testing and installation. Battery performance since launching of the NTS-2 satellite is discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 489-498
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  • 8
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    In:  CASI
    Publication Date: 2006-06-18
    Description: Test data developed primarily on low earth, but also some accelerated synchronous orbit data are presented for first 40 hour ampere hour boiler plate cells. Graphic data show the following characteristics: charge/discharge voltage; charge/discharge temperature; voltage; pressure; temperature; and discharge voltage.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 481-487
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  • 9
    Publication Date: 2006-06-18
    Description: The effects of overcharge and total cycling rate on one electrochemically impregnated and four chemically impregnated nickel electrodes are examined. Topics discussed include porosity distribution, electrode corrosion, electrolyte absorption and positive electrode involvement in the decrease in the amount of electrolyte in the separator. The electrochemically impregnated electrode is shown to be superior to all types of conventionally impregnated electrodes regardless of the loading level.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center. The 1977 Goddard Space Flight Center Battery Workshop; p 361-376
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  • 10
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    In:  CASI
    Publication Date: 2006-06-18
    Description: A nylon separator was placed in a flooded condition in K0H solution and heated at various high temperatures ranging from 60 C to 110 C. The weight decrease was measured and the molecular weight and decomposition product were analyzed to determine: (1) the effect of K0H concentration on the hydrolysis rate; (2) the effect of K0H concentration on nylon degradation; (3) the activation energy at different K0H concentrations; and (4) the effect of oxygen on nylon degradation. The nylon hydrolysis rate is shown to increase as K0H concentration is decreased 34%, giving a maximum rate at about 16%. Separator hydrolysis is confirmed by molecular weight decrease in age of the batteries, and the reaction of nylon with molecular oxygen is probably negligible, compared to hydrolysis. The extrapolated rate value from the high temperature experiment correlates well with experimental values at 35 degrees.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 389-398
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  • 11
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    In:  CASI
    Publication Date: 2006-06-18
    Description: Nylon separator degradation was examined as a function of temperature. Electrochemically active uncharged excess negative (overcharge protection)was measured by charging a cell venting it until it became fully charged, and continuing to overcharge the vent gas. The gas was analyzed as a function of time. The amount of hydrogen evolved was examined, and the cell voltage was observed as the oxygen and/or hydrogen evolved from the cell.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 345-354
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  • 12
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    In:  CASI
    Publication Date: 2006-06-18
    Description: The modular power system, which is the first intended use for the NASA standard battery, is basically a four foot by four foot by eighteen inch box which can handle a complement of three 20 ampere hour batteries or later on the intended use is for three 50 ampere hour batteries to be the full complement. The system is designed to be used as a plug on component on a multi mission modular spacecraft. It has as a design point a basically 1250 watt orbital average load. The way it breaks up in a near earth orbit it would be somewhere around 1,000 watts for everything except 10 minutes, and during any 10 minute period it may go up to a peak of 3,000 watt load. Features of the battery reviewed include criteria to store electrical energy, the battery package, the covers and cases, and electrolytes. The capacities expected are 90 percent, the average cell capacity for 24 C, 90 percent of the actual battery capacity of 19 C, and 85 percent of the actual 25 degree battery capacity at zero discharge voltage for 50 percent DOD new battery is in the vicinity expected or predicted of 26.4 volts.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 437-450
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  • 13
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    In:  CASI
    Publication Date: 2006-06-13
    Description: A brief description of the ITOS power systems is presented. The descriptions are from viewgraphs shown to the participants of the Workshop. A block diagram of ITOS power supply subsystem is presented along with graphs representing: ITOS voltage limit versus temperature; and battery charge-discharge current profiles over an orbit period.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: The 1977 Goddard Space Flight Center Battery Workshop; p 7-13
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  • 14
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    In:  CASI
    Publication Date: 2006-08-09
    Description: Observations of cosmic and gamma radiation by SAS-2 satellite are summarized and analyzed to determine processes responsible for producing observed galactic radiation. In addition to the production of gamma rays in discrete galactic objects such as pulsars, there are three main mechanisms by which high-energy (greater than 100 MeV) radiation is produced by high-energy interactions involving cosmic rays in interstellar space. These processes, which produce what may be called diffuse galactic gamma-rays, are: (1) the decay of pi mesons produced by interactions of cosmic ray nucleons with interstellar gas nuclei; (2) the bremsstrahlung radiation produced by cosmic ray electrons interacting in the Coulomb fields of nuclei of interstellar gas atoms; and (3) Compton interactions between cosmic ray electrons and low-energy photons in interstellar space.
    Keywords: ASTROPHYSICS
    Type: The Struct. and Content of the Galaxy and Galactic Gamma Rays; p 315-346
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  • 15
    Publication Date: 2006-08-09
    Description: Gamma ray astronomy is now beginning to provide a new look at the galactic structure and the distribution of cosmic rays, both electrons and nucleons, within the galaxy. The observations are consistent with a galactic spiral-arm model in which the cosmic rays are linearly coupled to the interstellar gas on the scale of the spiral arms. The agreement between the predictions of the model and the observations for regions of the plane where both 21-cm and 2.6-mm CO surveys exist emphasizes the need to extend these observations to include the entire plane. Future gamma-ray observations with more sensitivity and better angular resolutions, combined with these radio surveys, should shed new light on the distribution of cosmic rays, the nature of the galaxy, and the location and intensity of the spiral arms.
    Keywords: ASTROPHYSICS
    Type: The Struct. and Content of the Galaxy and Galactic Gamma Rays; p 301-314
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  • 16
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    In:  CASI
    Publication Date: 2006-08-09
    Description: The density distributions of pulsars in luminosity, period, Z-distance, and galactocentric distance were derived, using a uniform sample of pulsars detected during a 408-MHz pulsar survey at Jodrell Bank. There are indications of a fine-scale structure in the spatial distributions and evidence that there is a general correlation with other galactic populations and the overall spiral structure. The electron layer in our galaxy is shown to be wider than the pulsar layer and uniform on a large scale. The number of pulsars in the galaxy has been estimated and used to derive the pulsar birthrate.
    Keywords: ASTROPHYSICS
    Type: NASA. Goddard Space Flight Center The Struct. and Content of the Galaxy and Galactic Gamma Rays; p 265-282
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  • 17
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    In:  CASI
    Publication Date: 2006-08-09
    Description: The cosmic rays are an active gaseous component of the disk of the galaxy, and their propagation and containment is a part of the general dynamics of the disk. The sources of cosmic rays are a matter of speculation. The disk is inflated by the cosmic-ray gas pressure, P, comparable to the magnetic pressure B super 2/ 8 pi, but the rate of inflation is unknown. The time spent by the individual cosmic-ray particles in the disk is inversely proportional to the cosmic-ray production rate and may be anything from 100,000 to more than 10 million years. It is evident from the decay of Be(10) that the cosmic rays circulate through a volume of space perhaps ten times the thickness of the gaseous disk, suggesting a magnetic halo extending out approximately 1 kpc from either face of the disk. The cosmic rays may be responsible for the halo by inflating the magnetic fields of the disk. Extension of the fields to 1 kpc would imply a high production rate and short life of cosmic rays in the dense gaseous disk of the galaxy.
    Keywords: SPACE RADIATION
    Type: NASA. Goddard Space Flight Center The Struct. and Content of the Galaxy and Galactic Gamma Rays; p 283-299
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  • 18
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    In:  CASI
    Publication Date: 2006-08-09
    Description: Thermal radiation associated with the explosion of supernovae is investigated. High temperature is required to produce copious gamma radiation of this sort. It appears that type 11 supernovae do not release much of their energy as gamma ray continuum radiation.
    Keywords: ASTROPHYSICS
    Type: NASA. Goddard Space Flight Center The Struct. and Content of the Galaxy and Galactic Gamma Rays; p 257-264
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  • 19
    Publication Date: 2006-08-09
    Description: In order to draw implications from nearby gamma-ray emission, the different ways that can be used to obtain an estimate of the amount of matter on each line of sight are investigated. It is shown that, within present uncertainties, the cosmic ray intensity inside molecular clouds within 1 kpc from the sun is the same as the cosmic ray intensity measured at the sun. In the last part, what can be learned from a comparison of far infrared and gamma-ray data is discussed.
    Keywords: SPACE RADIATION
    Type: NASA. Goddard Space Flight Center The Struct. and Content of the Galaxy and Galactic Gamma Rays; p 229-236
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  • 20
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    In:  CASI
    Publication Date: 2006-08-09
    Description: Observations of the distribution of brightness at intermediate latitudes in the galaxy and of the edge-on spiral galaxy, NGC 891, indicate that the emissivity extends to heights of several kpc perpendicular to the plane. In several galaxies, the angular distributions of neutral hydrogen and nonthermal emission are roughly coextensive and show similar features such as spiral structure. If radio galaxies and normal galaxies with strong nuclear radio sources are excluded, there appears to be a proportionality between their total H(I) content and their nonthermal radio luminosity.
    Keywords: SPACE RADIATION
    Type: NASA. Goddard Space Flight Center The Struct. and Content of the Galaxy and Galactic Gamma Rays; p 189-202
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  • 21
    Publication Date: 2006-08-09
    Description: The degree of saturation characterizing low altitude emission observations of H(I) and the optical depth corrections to the derived column and volume densities are discussed. The amount of fine-scale velocity and spatial structure diluted by the instrumental limitations of the presently available surveys are described. The general problem of detailed mapping of H(I) in the galaxy is explored. Comparison is made between the distribution of H(I) and that of CO and several other galactic tracers. Atomic hydrogen is unique in its distribution, instead of being typical of many Population I constituents. As defined by atomic hydrogen, the galactic disk has a diameter fully twice as large as that defined by the ionized and molecular states of hydrogen, as well as by other molecules, supernova remnants, pulsars, gamma-radiation, synchroton radiation, and the youngest stars. It is also less confined to the galactic equator than most of the other constituents. The degree of small scale structure apparent in the molecular observations is much greater than that in the H(I) observations.
    Keywords: ASTROPHYSICS
    Type: NASA. Goddard Space Flight Center The Struct. and Content of the Galaxy and Galactic Gamma Rays; p 163-188
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  • 22
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    In:  CASI
    Publication Date: 2006-08-09
    Description: Data from the SAS-2 high-energy gamma-ray experiment reveal the existence of four pulsars emitting photons above 35 MeV. An attempt is made to explain the gamma-ray emission from these pulsars in terms of an electron-photon cascade that develops in the magnetosphere of the pulsar. Although there is very little material above the surface of the pulsar, the very intense magnetic fields (10 to the 12th power gauss) correspond to many radiation lengths which cause electrons to emit photons by magnetic bremsstrahlung and which cause these photons to pair-produce. The cascade develops until the mean photon energy drops below the pair-production threshold which is in the gamma-ray range; at this stage, the photons break out from the source.
    Keywords: ASTROPHYSICS
    Type: NASA. Goddard Space Flight Center The Struct. and Content of the Galaxy and Galactic Gamma Rays; p 109-118
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  • 23
    Publication Date: 2006-08-09
    Description: Considerations made in developing a model of pulsars are explored. Observational data seems to support the argument that pulsar magnetospheres may contain large masses of plasma. The cascade process resulting from pair creation enables one to interpret the X-ray emission from the Crab and Vela pulsars as synchrotron radiation. On the other hand, the optical radiation from the Crab pulsar is best understood as coherent curvature radiation. Radio emission is interpreted as curvature radiation produced by charge bunches moving along magnetic-field lines. Certain tests of this model are proposed.
    Keywords: ASTROPHYSICS
    Type: NASA. Goddard Space Flight Center The Struct. and Content of the Galaxy and Galactic Gamma Rays; p 99-108
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  • 24
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    In:  CASI
    Publication Date: 2006-08-09
    Description: Recent results in ground-based very high-energy (less than 10 to the eleventh power eV) gamma-ray astronomy are reviewed. The various modes of the atmospheric Cerenkov technique are described, and the importance of cosmic ray rejection methods is stressed. The positive detections (at approximately less than 10 to the 12th power eV) of the Crab pulsar that suggest a very flat spectrum and time-variable pulse phase are discussed. Observations of other pulsars (particularly Vela) suggest that these features may be general. The steady flux upper limits for the Crab Nebula are thus reconsidered, and a new value of the implied (Compton-synchrotron) magnetic field in the Nebula is reported. Evidence that a 4.8-hour modulated effect was detected at E sub gamma is less than 10 to the 12th power eV from Cyg X-3 is strengthened in that the exact period originally proposed agrees well with a recent determination of the X-ray period. The southern sky observations are reviewed, and the significance of the detection of an active galaxy (NGC 5128) is considered for source models and future observations.
    Keywords: SPACE RADIATION
    Type: NASA. Goddard Space Flight Center The Struct. and Content of the Galaxy and Galactic Gamma Rays; p 81-98
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  • 25
    Publication Date: 2006-08-09
    Description: High resolution data on the pulsed gamma-ray emission from the Crab and Vela pulsars are presented. The light curves of these two pulsars at gamma-ray energies show striking similarities. The measured pulsed intensity from Vela at energies greater than 50 MeV was found to be .000013 sq cm/sec. The energy spectrum is not consistent with a power law.
    Keywords: SPACE RADIATION
    Type: The Struct. and Content of the Galaxy and Galactic Gamma Rays; p 53-64
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  • 26
    Publication Date: 2006-08-09
    Description: Observation of 0.2 to 100 MeV-diffuse gamma-radiation emitted from a galaxy provides information on the intensities of 5 to 50 MeV/nucleon cosmic-rays and approximately less than 50-MeV electrons in interstellar space. Recent measurements of gamma-rays emitted from the galactic center region provide evidence for a diffuse continuum between 10 and 100 MeV, which is dominant over the pi-decay emission generated in high-energy nuclear collisions. The intensities of the recently reported nuclear line gamma-rays, also observed in the direction of the galactic center, require the presence of intense fluxes of low energy cosmic rays in the inner galaxy if the gamma-ray are produced on a galactic scale. Current detection techniques for 0.1 to 100 MeV gamma-ray measurements are summarized, and their capabilities for measuring the diffuse galactic emission are evaluated.
    Keywords: SPACE RADIATION
    Type: NASA. Goddard Space Flight Center The Struct. and Content of the Galaxy and Galactic Gamma Rays; p 65-80
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  • 27
    Publication Date: 2006-08-09
    Description: The COS-B experiment has observed approximately one-fourth of the galactic disk, including the galactic-center region, the galactic anticenter, and the Vela region. A completely automatic analysis of the events recorded during these observations reveals a galactic gamma ray emission from the three regions. In the galactic center and Vela regions, the disk emission distribution was measured. From these data, the existence of a local (less than 1 kpc) and a distant (greater than 3 kpc) emitting region is apparent in the general direction of the inner galaxy.
    Keywords: SPACE RADIATION
    Type: The Struct. and Content of the Galaxy and Galactic Gamma Rays; p 41-44
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  • 28
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    Publication Date: 2006-08-09
    Description: The COS-B satellite carries a single experiment, capable of detecting gamma rays with energies greater than 30 MeV to study the spatial, energy, and time characteristics of high-energy radiation of galactic and extragalactic origin. The capability to search for gamma ray pulsations is enhanced by the inclusion in the payload of a proportional counter sensitive of X-rays of 2 to 12 keV. The experiment was calibrated using particle accelerators. The results of these measurements are presented, and the performance of the system in orbit is discussed.
    Keywords: SPACE RADIATION
    Type: The Struct. and Content of the Galaxy and Galactic Gamma Rays; p 29-40
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  • 29
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    In:  CASI
    Publication Date: 2006-08-09
    Description: In October 1975, the high-energy gamma-ray flux from the Vela pulsar measured by COS-B was found to be 1.6 to 2.1 times higher than the flux measured by SAS-2 in 1973. This factor is too large to be accounted for by error in the COS-B calibration or analysis. This is supported by a comparison of the COS-B measurement of the narrow-line component from the galactic center region with the flux derived from the measurements of SAS-2; the COS-B flux comes out about 15 percent lower than the SAS-2 figure. It is interesting to note that a glitch in the pulsar period took place about 1 month prior to the COS-B observation; the previous glitch occurred about 1.5 years before the SAS-2 observation. The increased rotational energy loss after the glitch cannot simply explain the increased gamma-ray luminosity. If the two phenomena are related, the gamma-ray emission, absorption, or beaming process must be extremely sensitive to changes in rotational parameters. The existence is confirmed of a second region of enhanced radiation in the galactic anticenter in addition to that from the Crab pulsar.
    Keywords: SPACE RADIATION
    Type: The Struct. and Content of the Galaxy and Galactic Gamma Rays; p 45-52
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  • 30
    Publication Date: 2006-08-09
    Description: Gamma ray emission was detected from the radio pulsars PSR 1818-04 and PSR 1747-46, in addition to the previously reported gamma ray emission from the Crab and Vela pulsars. Because the Crab pulsar is the only one observed in the optical and X-ray bands, these gamma ray observations suggest a uniquely gamma ray phenomenon occurring in a fraction of the radio pulsars. PSR 1818-04 has a gamma ray luminosity comparable to that of the Crab pulsar, whereas the luminosities of PSR 1747-46 and the Vela pulsar are approximately an order of magnitude lower. SAS-2 data for pulsar correlations yielded upper limits to gamma ray luminosity for 71 other radio pulsars. For five of the closest pulsars, upper limits for gamma ray luminosity are found to be at least three orders of magnitude lower than that of the Crab pulsar. Gamma ray enhancement near the Milky Way satellite galaxy and the galactic plane in the Cygnus region is also discussed.
    Keywords: SPACE RADIATION
    Type: The Struct. and Content of the Galaxy and Galactic Gamma Rays; p 15-26
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  • 31
    Publication Date: 2006-08-09
    Description: Continuing analysis of the data from the SAS-2 high energy gamma ray experiment has produced an improved picture of the sky at photon energies above 35 MeV. On a large scale, the diffuse emission from the galactic plane is the dominant feature observed by SAS-2. This galactic plane emission is most intense between galactic longitudes 310 deg and 45 deg, corresponding to a region within 7 kpc of the galactic center. Within the high-intensity region, SAS-2 observes peaks around galactic longitudes 315, 330, 345, 0, and 35 deg. These peaks appear to be correlated with galactic features and components such as molecular hydrogen, atomic hydrogen, magnetic fields, cosmic-ray concentrations, and photon fields.
    Keywords: SPACE RADIATION
    Type: The Struct. and Content of the Galaxy and Galactic Gamma Rays; p 3-14
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  • 32
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    In:  CASI
    Publication Date: 2006-06-15
    Description: The results of an experiment to test storage effects on electric cells of a battery are presented and discussed. The type of cells were the 20 amp-hour OAO type. The various modes that were tested were the integration type mode, the trickle charge, the discharge shorted and the discharged OCV (open current voltage). Every six months the cells were reconditioned and approximately two weeks of tests were performed. The tests included three capacity checks, two zero-degree overcharge tests and an internal short test (the cells are shunted for 16 hours, the shunt removed and allowed to stand on local circuit recovery for 24 hours). The integration pack was discontinued after three years and the trickle charge shorted packs after five years.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 223-242
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  • 33
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    Publication Date: 2006-06-15
    Description: Some possible parameters which could be used to predict failures within packs of electrochemical cells based on measurements that are taken while the cells are cycling are discussed. Discharge and charge curves are presented and fitted to measure the efficiency of the cells in terms of voltage vs. time.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 181-195
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  • 34
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    Publication Date: 2006-06-15
    Description: A discussion is presented on the use of statistical analysis to develop a technique that will reliably predict the life of a battery.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 141-153
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  • 35
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    Publication Date: 2006-06-15
    Description: Prediction techniques are discussed for the cycle life of nickel cadmium space cells. Equations and graphs which incorporate such parameters as temperature and recharge are presented.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 173-179
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  • 36
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    In:  CASI
    Publication Date: 2006-06-15
    Description: A brief discussion on the accelerated testing of batteries is given. The statistical analysis and the various aspects of the modeling that was done and the results attained from the model are also briefly discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: The 1977 Goddard Space Flight Center Battery Workshop; p 137-140
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  • 37
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    In:  CASI
    Publication Date: 2006-06-14
    Description: The orbit data for the Intelsat 4 spacecraft is described. The performance and characteristics of the battery used for this spacecraft are discussed. Graphs are presented which relate battery voltage to various eclipse seasons.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 89-107
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  • 38
    Publication Date: 2006-06-14
    Description: The OSO-1 represents a recent vintage satellite, or more recent design satellite. A summary of the battery design used on OSO-1 is presented. The temperature effects on voltage and charging-discharging of the battery system are discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: The 1977 Goddard Space Flight Center Battery Workshop; p 43-54
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  • 39
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    In:  CASI
    Publication Date: 2006-06-14
    Description: Atmospheric Explorer (AE) is a 1971 power system design, using the heritage of the ITOS system. The system design and its operation are discussed. Problems of charging and discharging the batteries and the effects of temperature on these operations are discussed. A block diagram of the power supply electronics and some graphs related to voltage and temperature for the AE battery design are presented.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: The 1977 Goddard Space Flight Center Battery Workshop; p 15-23
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  • 40
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    In:  CASI
    Publication Date: 2006-06-14
    Description: A discussion is presented which gives an overview of the research and technological areas on nickel cadmium batteries at the Jet Propulsion Laboratory. Some of the topics covered include: goals; failure modes and mechanisms; factors of degradation and some possible solutions; energy density; and accomplishments for FY 77 and FY 78.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 119-132
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  • 41
    Publication Date: 2006-06-14
    Description: The battery was a three ampere hour nickel cadmium prismatic cell. The battery consists of 20 cells connected in series and there were two batteries per spacecraft. The battery operations (voltage and temperature) that the spacecraft sees during a normal operational day are discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: The 1977 Goddard Space Flight Center Battery Workshop; p 69-79
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  • 42
    Publication Date: 2006-06-14
    Description: The battery design of OAO-C (OAO-3) is given and consists of three-20 ampere hour 22 series connected cells in the battery. There are three batteries per spacecraft. The packaging configuration is described. The charging-discharging operations and the voltage potential of the battery system are discussed. Graphs are presented for the voltage limits (battery voltage versus temperature) and end of dark voltages (battery voltage versus ampere-hours discharged) of the battery system used on OAO-3. Data tables are also presented which give a summary of the battery performance and a comparison of OAO-3 with OAO A-2.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: The 1977 Goddard Space Flight Center Battery Workshop; p 55-79
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  • 43
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    In:  CASI
    Publication Date: 2006-06-18
    Description: Progress of four contractors in producing standard 20 AH nickel-cadmium cells meeting a capacity requirement of 24 + or - 2 AH and an envelope requirement listed in NASA/GSFC specification S-711-17 is reported. Among the requirements were 10 burn in cycles 24 C, 0 C, and 35 C capacity tests, charge efficiency tests and precharge verification tests.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: The 1977 Goddard Space Flight Center Battery Workshop; p 431-435
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  • 44
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    In:  CASI
    Publication Date: 2006-06-18
    Description: Solar array power systems for the space construction base are discussed. Nickel cadmium and nickel hydrogen batteries are equally attractive relative to regenerative fuel cell systems at 5 years life. Further evaluation of energy storage system life (low orbit conditions) is required. Shuttle and solid polymer electrolyte fuel cell technology appears adequate; large units (approximately four times shuttle) are most appropriate and should be studied for a 100 KWe SCB system. A conservative NiH2 battery DOD (18.6%) was elected due to lack of test data and offers considerable improvement potential. Multiorbit load averaging and reserve capacity requirements limit nominal DOD to 30% to 50% maximum, independent of life considerations.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 451-461
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  • 45
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    In:  CASI
    Publication Date: 2006-06-18
    Description: The graphite epoxy cell case and header developed as a means of weight reduction are discussed. Aspects considered include gas permeability, KOH compatibility, pressure and structural dynamic integrity, fiber orientation, fabrication process, cover-to-case sealing, terminal installation and sealing, reproducibility, exposure to the extractable materials that might influence the electrochemical portion of the cell, and electrical conductivity between the terminals.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 419-427
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  • 46
    Publication Date: 2006-06-14
    Description: A summary of the ATS battery design which is onboard the Applications Technology Satellite (ATS) is provided. The 15 ampere hour nickel cadmium cells were manufactured by Gulton, 19 series connected cells per battery, and there are two batteries in each spacecraft. The operating design life was two years in a synchronous orbit, and a maximum depth of discharge of 50 percent. The design temperature for the batteries in the spacecraft was 0 to 25 C, and the charge control consisted of 1 volt versus temperature on a constant percentage voltage. Also, C/10 current limit, and a commandable trickle charge rate, using C/20 or C/60. The undervoltage was sent across a 9 cell and a 10 cell group, and it was set at one volt average per group on either group.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: The 1977 Goddard Space Flight Center Battery Workshop; p 81-87
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  • 47
    facet.materialart.
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    In:  CASI
    Publication Date: 2006-06-14
    Description: The operation and systems design of a nickel cadmium battery system used on the Nimbus and LANDSAT satellites are discussed. Emphasis is placed on the charging-discharging operation of the battery system.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: The 1977 Goddard Space Flight Center Battery Workshop; p 25-42
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  • 48
    facet.materialart.
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    In:  CASI
    Publication Date: 2006-06-18
    Description: Three 18 AH Li-CF batteries with a polypropylene separator and using dimethyl sulfite in Li as F6 for the electrolyte will be placed in each shuttle solid rocket booster for range safety and frustrum location aid. Mechanical vibration, acceleration, random and design vibration, and discharge evaluation tests are discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 581-589
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  • 49
    facet.materialart.
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    In:  CASI
    Publication Date: 2006-06-18
    Description: Three lithium SO2 cells, two lithium CF cells, and a vinyl chloride cell, all with crimped seals, and all strictly experimental, were independently discharged on resistors. Three temperatures were used and several different storage temperatures. Discharge rate generally on the nominal discharges were 0.1 amp, 0.5 amp, and 1 amp. Tests results show that the crimp seals are inadequate, especially for the SO2 cells. Normal discharges present no hazards. All cells discharge to zero. The problem of lithium cell explosions, such as occurred during off-limits testing, is discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 557-567
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  • 50
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    In:  CASI
    Publication Date: 2006-06-18
    Description: The long duration exposure facility mission places temperature requirements of from -30 F to +150 F on the batteries to be used. A hermetically sealed lithium sulfur dioxide cell was tested to predict what the temperature of the battery would be over a given spectrum of temperatures of operation. Near the end of cell discharge, as the voltage started collapsing, a very high heat output rise due to chemical reaction took place. However, if the cells were thermally insulated, they vented, ignited, and burned if an attempt was made to discharge them all the way. The cells do not go into reversal. It was determined that the root of the problem was probably the chemical reaction between the lithium and the acetonitrite solvent. A redesigned cell is discussed as well as some alternates.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 565-580
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  • 51
    facet.materialart.
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    In:  CASI
    Publication Date: 2006-06-18
    Description: Experiences with batteries for the Apollo Soyuz Test Project are related and the need for safety criteria for space shuttle orbiter and payload battery handling and design is assessed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 545-556
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  • 52
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    In:  CASI
    Publication Date: 2006-06-18
    Description: Because of the disintegration of LaNi5 as the lattice expands on absorbing hydrogen, a nickel hydrogen cell similar to a nickel cadmium cell was designed. The positive electrode is wrapped in a microporous separator and the leads are insulated. A negative conducting grid is inserted and welded to the top of the can into an open ended container which is then turned upside down and filled so that LiNa5 powder occupies all the space not used by the rest of the components. The bottom of the can is then welded on. A fill tube is located either on the bottom or on the top of the can. When welded shut, the cell is put into a pressure bomb and the lanthanum nickel is activated at about 1,000 pounds of hydrogen. Electrolytes are added to the cell as well as whatever amount of hydrogen precharge desired, and the cell is sealed. Advantages and disadvantages of the cell are discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 533-543
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  • 53
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    In:  CASI
    Publication Date: 2006-06-18
    Description: Values for the capacity loss with time, naturally on open circuit stand, and information regarding the minimum amount of circuit charge needed to keep the cell charged can be determined from the self-discharge behavior of nickel hydrogen cells. Furthermore, the rate of reaction between hydrogen and a charged nickel electrode is also open for nickel cadmium batteries. In a nickel hydrogen cell, the hydrogen is stored as pressurized gas and the cell stack with the charge that is oxidized nickel-hydroxide electrode is in direct contact with the hydrogen. Therefore, the rate of reaction can be measured easily and precisely by monitoring the charge, the change in hydrogen pressure with time. Measures made on twelve 15 ampere hour nickel hydrogen cells of different stack configurations built for COMSAT are discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 525-531
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  • 54
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    In:  CASI
    Publication Date: 2006-06-18
    Description: Design criteria are discussed for a hermetic seal capable of withstanding the 450 C operating temperature of a lithium-metal sulfide battery system. A mechanical seal consisting of two high strength alloy metal sleeves welded or brazed to a conductor assembly and pressed onto a ceramic is described. The conductor center passes through the ceramic but is not sealed to it. The seal is effected on the outside of the taper where the tubular part is pressed down over and makes contact.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 355-360
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  • 55
    Publication Date: 2006-05-22
    Description: The spectral thermal optimization of solar cell configurations for various solar panel applications is considered. The method of optimization depends upon varying the solar cell configuration's optical characteristics to minimize panel temperatures, maximize power output and decrease the power delta from beginning of life to end of life. Four areas of primary investigation are: (1) testing and evaluation of ultraviolet resistant coverslide adhesives, primarily FEP as an adhesive; (2) examination of solar cell absolute spectral response and corresponding cell manufacturing processes that affect it; (3) experimental work with solar cell manufacturing processes that vary cell reflectance (solar absorptance); and (4) experimental and theoretical studies with various coverslide filter designs, mainly a red rejection filter. The Hughes' solar array prediction program has been modified to aid in evaluating the effect of each of the above four areas on the output of a solar panel in orbit.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Efficiency and Radiation Damage; p 127-132
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  • 56
    Publication Date: 2006-05-22
    Description: Normal isotopic silicon contains 3.05% of Si-30 which transmutes to P-31 after thermal neutron absorption, with a half-life of 2.6 hours. This reaction is used to introduce extremely uniform concentrations of phosphorus into silicon, thus eliminating the areal and spatial inhomogeneities characteristic of chemical doping. Annealing of the lattice damage in the irradiated silicon does not alter the uniformity of dopant distribution. Transmutation doping also makes it possible to introduce phosphorus into polycrystalline silicon without segregation of the dopant at the grain boundaries. The use of neutron transmutation doped (NTD) silicon in solar cell research and development is discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Efficiency and Radiation Damage; p 109-116
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  • 57
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    Publication Date: 2006-05-22
    Description: A novel cover slide is reported which increases solar cell output by reducing the reflection of light from the cover slide surface and by redirecting incident light so that none falls on the collection grids of the cell. The new cover slide is fabricated with a sawtooth surface having a periodicity equal to that of the solar cell grids. This configuration refracts the light so that it is directed onto the semiconductor surface between the grid lines. Conventional grid patterns obstruct 7-10 percent of the light incident on the cell; at least half of this loss has been recovered by using the sawtooth cover slide. In addition, surface reflection from the conventional coated cover slide is suppressed by presenting a second surface to any light reflected at the first plane of contact. This double reflection results in a greater reduction of the reflection loss from the cover slide than does an antireflection coating on a flat surface.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Efficiency and Radiation Damage; p 95-98
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  • 58
    Publication Date: 2006-05-22
    Description: Increased solar cell efficiencies are attained by reduction of surface recombination and variation of impurity concentration profiles at the n(+) surface of silicon solar cells. Diagnostic techniques are employed to evaluate the effects of specific materials preparation methodologies on surface and near surface concentrations. It is demonstrated that the MOS C-V method, when combined with a bulk measurement technique, yields more complete concentration data than are obtainable by either method alone. Specifically, new solar cell MOS C-V measurements are combined with bulk concentrations obtained by a successive layer removal technique utilizing measurements of sheet resistivity and Hall coefficient.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Efficiency and Radiation Damage; p 69-79
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  • 59
    Publication Date: 2006-05-22
    Description: Quantitative analysis of the electron beam-induced current and the dependence of the effective diffusion length of the minority carriers on the penetration depth of the electron beam were employed for the analysis of the carrier recombination characteristics in heavily doped silicon layers. The analysis is based on the concept of the effective excitation strength of the carriers which takes into consideration all possible recombination sources. Two dimensional mapping of the surface recombination velocity of P-diffused Si layers will be presented together with a three dimensional mapping of minority carrier lifetime in ion implanted Si. Layers heavily doped with As exhibit improved recombination characteristics as compared to those of the layers doped with P.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Efficiency and Radiation Damage; p 59-68
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  • 60
    Publication Date: 2006-05-22
    Description: Silicon and gallium arsenide solar cell developments are reviewed. The rationale for these efforts are cited showing the reasons for placing emphasis on survivability as well as high conversion efficiency.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Efficiency and Radiation Damage; p 25-31
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  • 61
    Publication Date: 2006-05-22
    Description: One potential means of improving the efficiency of solar cells especially after space irradiation is to incorporate built-in fields into the device through the use of impurity doping gradients. A detailed numerical calculation of solar cell performance has been used to study various types of doping gradients. In general, the predicted improvements in performance have been less than previously reported due to various device effects such as, high injection and the dependence of lifetime on doping density.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Efficiency and Radiation Damage; p 33-50
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  • 62
    Publication Date: 2006-05-22
    Description: Low cost solar cells and arrays with high end-of-life efficiency are evaluated through two approaches: one, to obtain increased device efficiency at no increase in cost and two, to reduce the manufacturing costs of space solar cells and arrays. Technology efforts encompass high efficiency epitaxial cells, high efficiency wraparound contact solar cells, economical diffusion sources, automated cell fabrication and development of easily applied, durable cover glasses. The examination of ion-implanted profile tailored junctions and additional development of screen printed contact technology to cell development are also considered.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Solar Cell High Efficiency and Radiation Damage; p 3-6
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  • 63
    Publication Date: 2006-05-22
    Description: Laboratory tests and flight experiments showed that solar cells can be produced in quantity, that they are suitable for space flight applications, and that the power produced ranged from 20 to 35% more than that of conventional cells. In a benign flight environment, the cells degraded at approximately the same rate as conventional cells. In synchronous orbit, the rate exceeded that of conventional cells, but high efficiency cells still showed significant power advantage after two years. Irradiation test results showed the voltage-temperature coefficients to be comparable to conventional cells. However, current-temperature coefficients were not only higher initially, but also increased significantly with irradiation. Although thin cells with good performance characteristics were made, significant problem areas pertinent to production were disclosed, particularly for cells with thickness of 0.100 mm or less. The overall program led to the use of advanced high efficiency cells on the International Sun-Earth Explorer solar panels.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Solar Cell High Efficiency and Radiation Damage; p 7-23
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  • 64
    Publication Date: 2006-05-24
    Description: Ultraviolet damage to the new violet and non-reflective type solar cell assemblies, was studied, and potential advantages of using coverslides with no filters or filters with cut-off wavelengths below 0.35 micron were determined. The experiments consisted of three types of tests on fused silica coverslides with 0.35- and 0.30-micron cut-off filters and no cut-off filters, as well as on ceria-doped microsheet coverslides. Ultraviolet irradiation for over 1500 hours at one sun conditions (AMO) was carried out under vacuum of about 1 million torr. Nearly identical results for non-reflective type cells with 0.35-micro cut-off filters or ceria-doped coverslides were obtained. The 0.30-um filtered cell shows greater than average degradation. The unfiltered cell shows an abrupt drop in the first 20 UVSH and very little subsequent degradation.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Efficiency and Radiation Damage; p 227-229
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  • 65
    Publication Date: 2006-05-24
    Description: Close examination of the interaction of the energetic knock-on atoms with the local lattice environment reveals a damage mechanism which does satisfy the experimental data on proton irradiation of silicon. A proton-atom interaction with high energy transfer is considered where the proton path is delineated by a trail of ionization, and the silicon ion path is characterized by much heavier ionization terminating in a dense displacement cluster. At collision, many of the silicon electrons are stripped off, and the resulting energetic ion subsequently loses energy rapidly by Coulomb interaction with bound electrons. The rate of energy loss depends on the charge state and velocity of the knock-on ion. For ion energies in excess of 1 MeV, the intensity of ionization is sufficient to permit lattice atoms, stripped of their binding electrons, to reorient randomly before having an opportunity to recombine with electrons and re-establish the lattice. The path of a knock-on ion thus becomes a thin cylinder of amorphous material within the crystal. Amorphous silicon has a Fermi level closer to mid-band than does single crystal silicon, and a strong field therefore, results around this damaged region. The field produces a large depletion region, representing a very large capture cross section for minority carriers.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Efficiency and Radiation Damage; p 221-223
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  • 66
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    Publication Date: 2006-05-24
    Description: The motivation for developing GaAs solar cells is based on their superior efficiency when compared to silicon cells, their lower degradation with increasing temperature, and the expectation for better resistance to space radiation damage. The AMO efficiency of GaAs solar cells was calculated. A key consideration in the HRL technology is the production of GaAs cells of large area (greater than 4 sg cm) at a reasonable cost without sacrificing efficiency. An essential requirement for the successful fabrication of such cells is the ability to grow epitaxially a uniform layer of high quality GaAs (buffer layer) on state-of-the-art GaAs substrates, and to grow on this buffer layer the required than layer of (AlGa)As. A modified infinite melt liquid phase epitaxy (LPE) growth technique is detailed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Efficiency and Radiation Damage; p 149-157
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  • 67
    Publication Date: 2006-05-24
    Description: A new double graded band-gap (DGBG) Al sub x Ga sub l-x As-Al sub z Ga sub l-z As solar cell has potential for providing high efficiency performance throughout the entire life of a solar cell in a space environment. A preliminary theoretical analysis indicates that short circuit current available from an optimized DGBG cell is slightly larger than that of a previously reported single graded band-gap cell. However, the DGBG cell potentially offers a substantial improvement in radiation resistance of the base region.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Solar Cell High Efficiency and Radiation Damage; p 139-147
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  • 68
    Publication Date: 2006-05-24
    Description: The present status of the GaAlAs/GaAs heteroface solar cell program is reported. Studies have been concentrated on GaAlAs/GaAs heteroface solar cells; however, some research has been conducted on thin junction, diffused GaAs solar cells. Emphasis has been on obtaining high efficiency (18% to 20%) GaAs solar cells. Two problems that have limited the efficiency of GaAs solar cells are the high recombination velocity of carriers near the surface and the low minority carrier diffusion length in n-GaAs.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Solar Cell High Efficiency and Radiation Damage; p 133-138
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  • 69
    Publication Date: 2006-01-12
    Description: Problems encountered on Skylab prompted the development of a reconditioning circuit which involves a DC to DC converter, a circuit sensing device, and the capability of switching several size reconditioners onto a circuit. Across each cell there is a full bridge rectifier. During battery discharge, if there is low cell voltage, the reconditioning systems holds that voltage up and permits discharge to continue on the system. When the cell is good, the voltage is up about one volt, the diodes are back, or reversed biased, and the current drawn out of the system is very low. The system has a standby power thrown at about one volt. As the voltage drops on a cell, the circuit strts picking up the load and helps hold the overall battery voltage up.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 305-313
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  • 70
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    In:  CASI
    Publication Date: 2006-01-12
    Description: Various steps followed in analyzing the electrolyte, separator, and electrodes are reviewed. Specific emphasis is given to scanning electron microscopic and metallographic analysis of the plates. Cadmium migration is defined, its effects and causes are examined, and methods for its reduction in cells are suggested.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 377-388
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  • 71
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    In:  CASI
    Publication Date: 2006-06-18
    Description: A discussion on cell reversal during flight is presented. Data tables and graphs are also presented to clarify the discussion.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 285-292
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  • 72
    Publication Date: 2006-06-18
    Description: A mechanism which allows a cell voltage reversal in a nickel cadmium battery are discussed. The effects of reconditioning and the characteristics of Ni-Cd cells during voltage reversal at low overdischarge rates are outlined. Graphs are presented for: (1) hydrogen pressure decay-effect of state of charge (open circuit stand); (2) hydrogen pressure increase during overdischarge; (3) hydrogen pressure decay-effect of temperature (cells terminals connected through resistors); (4) cell, positive and negative electrode voltage during reversal when reconditioning a 13 cell-24-Ah battery pack through a 40 Omega resistor; (5) pressure discharge current and recombination current during voltage reversal when reconditioning a 13 cell-24-Ah battery pack through a 40 Omega resistor; (6) theoretical hydrogen gas pressure if there were no recombination; and (7) effect of hydrogen pressure on recombination rate during overcharge.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 271-283
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  • 73
    Publication Date: 2006-06-15
    Description: Some real life data on the flight performance and reconditioning on the Communications Technology Satellite are presented. There are two 24-cell nominal 5 amp-hour nickel cadmium batteries on board. The two batteries are operated in parallel with isolating diodes in between and permanently connected to the housekeeping buses. The recharge can be at C over 10 or C over 20 to a 1.4 charge/discharge ratio; and recharge is terminated either when a computed 1.4 charge/discharge ratio is reached, or a charge voltage peak is reached.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 245-257
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  • 74
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    In:  CASI
    Publication Date: 2006-06-15
    Description: The long-term effects of storing batteries over a period of years prior to their use in a synchronous orbit application are discussed. A previous experiment is discussed where life testing was performed on cells after having stored the battery for a period of three years with the cell shorted and at a temperature on the order of 5-10 C. The test consisted of performing a sequence of 10 simulated eclipse seasons (equivalent in cycling of five years in synchronous orbit). Results of this test indicated very little degradation and change in the physical and chemical conditions of the cell. The program was extended for an additional year (battery was stored for four years) under the same conditions and testing. The results of the four year storage (one exception) indicate that no further change occurred that is significant from the three year test.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 219-222
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  • 75
    Publication Date: 2006-06-15
    Description: An engineering evaluation of the Multimission Modular Spacecraft power supply is presented. The spacecraft has one charger with eight commandable voltage versus temperature levels. Graphs are presented which represent: (1) cell voltage limits vs. temperature; (2) charge ratio vs. temperature; (3) effect of 0.0 percent impedance unbalance at 10 C; (4) shorted cell at 10 C; and (5) discharge voltage profile at 10 C.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: The 1977 Goddard Space Flight Center Battery Workshop; p 197-211
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  • 76
    facet.materialart.
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    In:  CASI
    Publication Date: 2006-06-18
    Description: A typical 625 Inconel pressure vessel, equipped with four thermocouples, has voltage taps not only for the cell, but for each of the several packs inside the container. In a two-stack design, a weld ring is used to separate the packs which, joined together, form one solid group. In the four-stack design, stacks are separated mechanically with about half inch Plexiglas and are connected through the center. Electrolytes are forced out by vacuum. The two stack design is intended for 500 psi and was pressure tested up to 1,000. The problem of electrolyte shorts is discussed and possible solutions for its correction are given.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 519-524
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  • 77
    facet.materialart.
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    In:  CASI
    Publication Date: 2006-06-18
    Description: A brief history of the SATCOM satellites is given. Cell design and battery operating characteristics are outlined and discussed. Graphs are presented comparing reconditioning parameters such as voltage, temperature, time and discharge.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 293-304
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  • 78
    facet.materialart.
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    In:  CASI
    Publication Date: 2006-06-18
    Description: Periodic capacity checks are assessed as well as the effects of periodic discharges on the cycle life and the performance of cells during the cycle life. Topics discussed include the effect of the amount of electrolyte on cell capacity at 35 C; battery design for spacecraft; electrolyte starvation theory; battery separator degradation; negative electrode stability; voltage regulation; operating temperatures; and integration of reconditioning systems using microprocessors.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: The 1977 Goddard Space Flight Center Battery Workshop; p 315-343
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  • 79
    facet.materialart.
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    In:  CASI
    Publication Date: 2006-06-18
    Description: Results of cyclic tests on seven 3-cell 100 A-H nickel cadmium batteries on 1.5 hr cycles are presented. The failure of the nylon and polypropylene separators was not analyzed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 475-478
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  • 80
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2006-06-18
    Description: The capabilities of photovoltaic, nuclear reactor, and solar thermal systems are assessed for the space construction base. Topics covered include Brayton conversion, thermionic conversion, and thermo-electric conversion. The effectiveness of nickel cadmium and nickel hydrogen batteries are discussed as well as that of regenerative fuel cells. The verification of long cycle life for nickel hydrogen systems is recommended.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 463-474
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  • 81
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2006-06-18
    Description: Batteries designed for the defense satellite communications system were modified to meet increased power requirements. A stainless steel case for the cell, approximately 4 inches wide, 4 1/2 inches high and 1 inch thick, with a weld down a narrow edge, has 12 mil 304-L stainless steel side walls and a 19 mil 304-L stainless bottom. A dip-brazed 60-61 aluminum retainer is electrically separated from the steel case by 15 mils of potting compound. The thickness of the compound varies from 10 to 20 mils, except at the bottom, where it is 20 to 30 mils thick. Pressure test results are discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 409-417
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  • 82
    facet.materialart.
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    In:  CASI
    Publication Date: 2006-06-18
    Description: The thickness, moisture content, exchange capacity, tensile strength, diffusion characteristics, stability, and electrical properties are discussed for the 2291 radiation-grafted separator used in military vented nickel cadmium aircraft batteries. A regression analysis of separator resistance as a function of temperature and KOH concentration is included.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 399-408
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  • 83
    facet.materialart.
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    In:  Other Sources
    Publication Date: 2011-08-19
    Description: Attention is given to spatial dependences exhibited by spacecraft measurements obtained between 1 and 30 AU, together with temporal variations occurring between solar activity cycle maxima and minima. At 1-3 AU radial distances, shocks develop in association with the corotating solar wind streams characterizing solar minimum and accelerate solar wind evolution with distance while heating the solar wind and generating waves and turbulence. At solar maximum, shocks are observed more frequently at 1 AU but still in association with transient solar events; acceleration leading to energetic storm particles is observed both within and beyond 1 AU. The superimposed effect of large numbers of intense shocks may be responsible for the solar cycle modulation of galactic cosmic rays.
    Keywords: ASTROPHYSICS
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  • 84
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    In:  Other Sources
    Publication Date: 2011-08-19
    Description: Early results from, and research initiatives warranted by, the earth-based observations of Halley's near-nucleus and related phenomena are reviewed. Where appropriate, this information is combined with spacecraft data obtained by the various flight projects. The basic objective is to gain a greater insight into the nature of the comet's nucleus and its environment.
    Keywords: ASTROPHYSICS
    Type: Advances in Space Research (ISSN 0273-1177); 5; 12, 1; 307-316
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  • 85
    Publication Date: 2011-08-19
    Description: Doppler and ranging measurements using the radio signal of the Giotto spacecraft were taken before, during, and after the encounter with Comet Halley on Mar. 13, 14, 1986. The spacecraft velocity was found to decrease by a total of 23.3 cm/s due to impacting gas and (primarily) dust in the cometary atmosphere. A preliminary dust production rate of 1000 kg/s is found to be consistent with this deceleration. Power spectra of the carrier phase fluctuations reveal an increase in level and a flattening of the spectrum just prior to encounter, presumably associated with the enhanced dust impact rate. Finally, simulated Doppler time profiles are computed using the radial dependence of plasma density observed by the Giotto in situ investigations. It is shown that the cometary electron content profile would have been clearly seen if a dual-frequency downlink radio configuration had been available at encounter.
    Keywords: ASTROPHYSICS
    Type: Advances in Space Research (ISSN 0273-1177); 5; 12, 1
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  • 86
    facet.materialart.
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    In:  Other Sources
    Publication Date: 2011-08-19
    Description: Highlights of infrared observations of the dust are discussed and compared with first results from the space probes. An emission feature was detected at 3.4 microns; the 10 and 20 micron silicate features were well-observed; and far-infrared data out to 160 micron were obtained. Organic material seems to be abundant in grains and may explain the 3.4 micron emission. Calculations are presented for one example of organic material. A component of the grains may volatize at temperatures around 300 K.
    Keywords: ASTROPHYSICS
    Type: Advances in Space Research (ISSN 0273-1177); 5; 12, 1; 325-334
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  • 87
    Publication Date: 2011-08-19
    Description: Bow-shock movements at Comet Halley are inferred from the discrete spectra of the cometary kilometric radiation (30-195 kHz); the observed emissions can be interpreted as being generated and propagating from the moving shock. The shock motion is possibly associated with the time variation of the solar wind and cometary outgassing. It is concluded that these plasma wave phenomena are manifestations of ion pick-up processes, which occur even in a remote region 7 million to 10 million km from the cometary nucleus.
    Keywords: ASTROPHYSICS
    Type: Advances in Space Research (ISSN 0273-1177); 5; 12, 1; 83-88
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  • 88
    facet.materialart.
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    In:  Other Sources
    Publication Date: 2011-08-19
    Description: Observational data on CNO abundance ratios in red giants and the interstellar medium (ISM) are analyzed for the implications for the production and distribution of CNO nuclides. The data included isotope abundance measurements for the atmospheres and recent ejecta of cool giants, e.g., carbon stars, S-type stars, red supergiants and oxygen-rich giants beginning an ascent of the giant branch. The contribution of intermediate-mass stars to galactic nuclear evolution is discussed after comparing red giant abundances with ISM abundances, particularly the isotopes O-16, -17 and -18. The O-12/O-18 ratios of red giants are distinctly different from those in interstellar molecular clouds. The CNO values also vary widely from the values found in the solar system.
    Keywords: ASTROPHYSICS
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  • 89
    facet.materialart.
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    In:  Other Sources
    Publication Date: 2011-08-19
    Description: Isotope production, particularly CNO, which are enhanced in novae events and the interstellar medium (ISM) by novae are discussed in terms of emission-line data taken a few weeks after novae events. The emission-line abundances emerge only after the fading of absorption spectrum, and are also detectable in thin shells which sometimes, though rarely, form after novae. CNO abundances in these shells are equivalent to those observed in fading novae, with CNO/H ratios being 100 times solar values. Possible heavy element production pathways in the events and their shrinking are discussed, along with observation techniques for detecting CNO isotopes through absorption data on atomic transitions in novae ejecta and the ISM.
    Keywords: ASTROPHYSICS
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  • 90
    Publication Date: 2011-08-19
    Description: Measurements of longitudinal variations in the brightness and in the latitude of the solar system dust bands recently discovered by IRAS will determine the orbital elements of the particles involved and may discriminate between cometary and asteroidal models of the origin of these bands. The expected variations for bands of dust particles with common orbital elements and small eccentricity and inclination are calculated as functions of semimajor axis.
    Keywords: ASTROPHYSICS
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  • 91
    Publication Date: 2011-08-19
    Description: The consequences which arise from the mutual collisions occurring between interplanetary meteoroids, the Poynting-Robertson (PR) effect and the radiation pressure ejection of small meteoroids are examined. The size distribution and flux of micrometeoroids at 1 AU are derived and the dependence of spatial density on distance from the sun is established. The following conclusions are made: (1) the lifetimes of meteoroids with masses approximately greater than 0.00001 g are dominated by catastrophic collisions; (2) after bering crushed by collisions, 70 to 85 percent of this mass will be in the form of zodiacal light particles (with masses in the range of 10 to the -10th g to 10 to the -5th g) which will in part be transported by the PR effect towards the sun where they will evaporate; (3) the 15 to 30 percent of the collisional fragments which have masses approximately less than 10 to the -10th g will, for the most part, be injected into hyperbolic orbits by radiation pressure.
    Keywords: ASTROPHYSICS
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  • 92
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    In:  Other Sources
    Publication Date: 2011-08-19
    Description: Everhart's (1967) formulation is used to determine the correlation between the probability of discovering a comet and the size of its nuclear radius. The analysis is concentrated on comets that are not more than two or three hundred meters in diameter; hence, heliocentric variations in cometary brightness can be neglected. The effect of cometary physical decay is also considered, and a strong observational bias against the detection of small active comets is found. The following three factors are involved: (1) small comets must pass closer to the earth than large comets in order to be detected, (2) the resulting higher angular velocity for nearby comets leads to a decrease in the time available to discover a small comet, and (3) small comets physically decay and vanish faster than do large comets.
    Keywords: ASTROPHYSICS
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  • 93
    Publication Date: 2011-08-19
    Description: The Infrared Astronomical Satellite (IRAS) has completed a sensitive, highly redundant survey of the full sky in four broad photometric bands at 12, 25, 60, and 100 micrometers wavelength. The survey measured interplanetary dust emission over elongation angle ranging from 60 to 120 degrees. Bright emission from the main cloud is consistent with optically thin blackbody emission. The grains are evidently quite black, with an 'apparent albedo' of about 0.07. The data show clear evidence for deviation of the dust symmetry surface from the ecliptic plane. Surprising bands of emission were discovered near the ecliptic plane and about ten degrees on either side of it. The heliocentric distance of this material, suggested to be asteroidal in origin, is inferred to be about 2.5 AU from both color temperature and parallax measurements.
    Keywords: ASTROPHYSICS
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  • 94
    Publication Date: 2011-08-19
    Description: The gaseous components studied in H I and OH absorption against the extragalactic radiosources 3C123 and 3C111 are found to be the low-density edges of condensations of a few 100 solar masses. The densest part of one of these condensations has a structure similar to that found in other dark clouds: it is fragmented into several cores of a few solar masses, with an orbital velocity dispersion of about 2 km/s. In turn, the extended low-density layer, optically thick in CO (2-1), is not a common feature. It depends on the ambient UV field, but the dust temperature in the core may control its existence. Even more critically; it is found that the lower is the dust temperature, the less massive is the core and the more extended is the envelope around it, for a given total mass in a given external pressure.
    Keywords: ASTROPHYSICS
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  • 95
    facet.materialart.
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    In:  Other Sources
    Publication Date: 2011-08-19
    Description: The role of Cepheid variables in establishing the inner distance scale to nearby galaxies is discussed. Emphasis is placed on the necessity for broad wavelength coverage in attempting to account for metallicity differences and reddening internal to the parent galaxies. In addition linear detectors are essential in minimizing the effects of any unresolved background contribution to the photometry. Recent infrared observations of Cepheids in Local Group galaxies are surveyed and all published data on extra galactic Cepheids are presented for convenient access.
    Keywords: ASTROPHYSICS
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  • 96
    Publication Date: 2011-08-19
    Keywords: ASTROPHYSICS
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  • 97
    Publication Date: 2011-08-19
    Description: The possibility is examined that in the course of its dynamical evolution, a single mass of interstellar gas would exhibit properties of diffuse clouds, dense clouds and finally also of clouds perturbed by shocks or intense UV or X-ray radiation generated by a star of its own creation. This concept provides a common thread through the bewildering diversity of physical and chemical compositional properties shown by interstellar clouds. From this perspective, instead of being static objects, interstellar clouds are possibly incessantly evolving from initially diffuse to later dense state and then to star formation which ultimately restructures or disperses the remaining cloud material to begin the whole evolutionary process once again. Based on a simplified study of interstellar chemistry from a dynamical perspective, the ideas are presented as an heuristic: to encourage thought on the future direction of molecular astrophysics and the need to consider the chemical behavior of interstellar clouds in conjunction with, rather than in isolation from, their dynamical behavior. A physical basis must be sought for the semiempirical temperature formula which has been given a critical role in the collapse of diffuse clouds. Self-shielding effects in the chemistry of CO were neglected and this drawback should be removed; the ability of the model to explain the fractional abundances of more complex molecules, such as cyanopolyynes, should be examined.
    Keywords: ASTROPHYSICS
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  • 98
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    In:  Other Sources
    Publication Date: 2011-08-19
    Description: The basis of our knowledge about the structure and composition of a comet nucleus is examined. Such knowledge is inferred from observations of the cometary atmosphere (coma). However, photodissociation, photoionization, and chemistry destroy the mother molecules evaporating from the nucleus. To extract the primary information, the chemical kinetics and the physics of the coma are modeled with a computer and the results are compared with coma observations. The physics and chemistry for a dust free coma are described taking into account energy balance, multi-fluid flow for fast atomic and molecular hydrogen and the bulk fluid, and the transition from a collision dominated inner region to the free molecular flow outer region. Special attention is paid to the molecular data requirements for the current modeld and for extended models which will include solar wind interaction and dust. Such models are an important tool in support of the Giotto mission to Halley's comet, in the analysis and interpretation of coma observations, and in the understanding of the earliest history of the solar system.
    Keywords: ASTROPHYSICS
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  • 99
    Publication Date: 2011-08-19
    Description: The engineering costs and performance of a nominal 25,000 scmd (883,000 scfd) photochemical plant to produce dihydrogen from water were studied. Two systems were considered, one based on flat-plate collector/reactors and the other on linear parabolic troughs. Engineering subsystems were specified including the collector/reactor, support hardware, field transport piping, gas compression equipment, and balance-of-plant (BOP) items. Overall plant efficiencies of 10.3 and 11.6 percent are estimated for the flat-plate and trough systems, respectively, based on assumed solar photochemical efficiencies of 12.9 and 14.6 percent. Because of the opposing effects of concentration ratio and operating temperature on efficiency, it was concluded that reactor cooling would be necessary with the trough system. Both active and passive cooling methods were considered. Capital costs and energy costs, for both concentrating and non-concentrating systems, were determined and their sensitivity to efficiency and economic parameters were analyzed. The overall plant efficiency is the single most important factor in determining the cost of the fuel.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: International Journal of Hydrogen Energy (ISSN 0360-3199); 10; 10, 1; 633-643
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  • 100
    Publication Date: 2011-08-19
    Description: Various methods outlined for indirect planetary detection would greatly benefit (in some cases require) the determination of the planetary orbital plane, which is theoretically equivalent to the stellar equatorial plane. Determining the stellar space orientation, therefore, would greatly benefit extrasolar planetary detection. Stellar rotation periods determined from short-term variations in Ca II H and K sunspot emission are utilized together with both stellar radii measurements and Doppler-broadened spectral line profiles to get the stellar inclination to the line of sight. The clocklike on-the-plane-of-the-sky component determination utilizes the concentration of sunspot-associated plage areas at central stellar latitudes when viewed in Ca II H or K emission. One can perform Ca II H and K emission speckle interferometry to measure the clocklike angle of this stellar Ca II H and K emission band, modeling it as an elliptical intensity distribution. Both components should be determinable to within 10 deg for at least the resolvable fifth magnitude stars.
    Keywords: ASTROPHYSICS
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