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  • GEOPHYSICS  (170)
  • Chemical Engineering  (70)
  • 1980-1984  (240)
  • 1983  (240)
  • 1
    Publication Date: 2011-08-18
    Description: A ground-based search for stratospheric 35-ClO was carried out using an infrared heterodyne spectrometer in the solar absorption mode. Lines due to stratospheric HNO3 and tropospheric OCS were detected at about 0.2 percent absorptance levels, but the expected 0.1 percent lines of ClO in this same region were not seen. We find that stratospheric ClO is at least a factor of seven less abundant than is indicated by in situ measurements, and we set an upper limit of 2.3 x 10 to the 13th molecules/sq cm at the 95 percent confidence level for the integrated vertical column density of ClO. Our results imply that the release of chlorofluorocarbons may be significantly less important for the destruction of stratospheric ozone (O3) than is currently thought. Previously announced in STAR as N83-27518
    Keywords: GEOPHYSICS
    Type: Science (ISSN 0036-8075); 221; July 15
    Format: text
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  • 2
    Publication Date: 2019-06-28
    Description: Auroral emission features at high geomagnetic latitudes are identified and characterized using simultaneous optical and particle data from the ISIS-2 satellite. Polar cap arcs are identified from two-dimensional geomagnetic transforms of the optical data along with precipitating electron data for the time at which the satellite is on the field line intersecting the arc. No precipitating protons were detected for any of the arc crossings. The precipitations particle characteristics include: (1) an electron energy spectrum with a peak in the range 350-750 eV superposed on a soft spectrum like that observed in polar rain; (2) a normally isotropic pitch angle dependence, with the exception that field-aligned fluxes are observed in association with an inverted 'v' event; and (3) an energy flux range of approximately 0.8-3 erg/(sq cm s). A possible explanation of the observed precipitating particle characteristics is that parallel electric fields are accelerating polar rain type spectra at an altitude of several thousand km.
    Keywords: GEOPHYSICS
    Type: Planetary and Space Science; 31; Feb. 198
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  • 3
    Publication Date: 2019-06-28
    Description: The spacecraft remained close to or within a previously unexplored part of the distant (60-220 earth radii) geomagnetic tail nearly continuously from January 1 to March 30, 1983. Analysis of the data reveals that all of the plasma regimes identified previously with near-earth measurements (plasma sheet, low-latitude boundary layer, plasma mantle, lobe, and magnetosheath) remain recognizable in the distant tail. These regimes, however, are found to be intermingled in a more chaotic fashion than near the earth. Within the plasma sheet at approximately 200 earth radii, typical flow velocities are about 500 km/s tailward, considerably higher than in the near-earth plasma sheet. Earthward flow within the plasma sheet is observed occasionally, indicating the temporary presence of a neutral line beyond 220 earth radii. Also found are strong bidirectional electron anisotropies throughout much of the distant plasma sheet, boundary layer, and magnetosheath.
    Keywords: GEOPHYSICS
    Type: Geophysical Research Letters (ISSN 0094-8276); 10; Sept
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  • 4
    Publication Date: 2019-06-28
    Description: A ground-based search for stratospheric 35-ClO was carried out using an infrared heterodyne spectrometer in the solar absorption mode. Lines due to stratospheric HNO3 and tropospheric OCS were detected at about 0.2% absorptance levels, but the expected 0.1% lines of ClO in this same region were not seen. We find that stratospheric ClO is at least a factor of seven less abundant than is indicated by in situ measurements, and we set an upper limit of 2.3x10 to the 13th molecules/sq cm at the 95% confidence level for the integrated vertical column density of ClO. Our results imply that the release of chlorofluorocarbons may be significantly less important for the destruction of stratospheric ozone (O3) than is currently thought.
    Keywords: GEOPHYSICS
    Type: NASA-TM-85026 , NAS 1.15:85026
    Format: application/pdf
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  • 5
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 29 (1983), S. 79-86 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The kinetics of reaction between CO2 and lime is investigated in the range of 673 to 998 K with a view to examining the effects of product layer deposition and variations in the limestone calcination atmosphere. The reaction is initially rapid and chemically controlled and goes through a sudden transition to a much slower regime controlled by diffusion in the product CaCO3 layer. The magnitude of the estimated product layer diffusivity is in the range of 10-18 to 10-21 m2/s, the corresponding activation energy is 88.9 ± 3.7 kJ/mol below 688 K and 179.2 ± 7.0 kJ/mol above that temperature, suggestive of solid state diffusion. Plausible mechanisms are discussed.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 29 (1983), S. 625-631 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The mixed oxide system of copper and tin and the active single oxide, Cu2O, were compared for reducibility of the copper ion, relative number and type of active sites, and reaction kinetics. The enhanced selectivity of the mixed oxides may result from the formation of highly selective sites at the expense of less selective sites. The reducibility of the copper ion in the mixture is influenced by the oxidation state of the tin ion. The reactant and product reaction orders are the same for both catalysts but the mixed oxides are more sensitive to inhibition by water. The catalyst composition affects the energetics of the reaction over the copper-tin oxide catalysts.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A new apparatus to measure partition coefficients Ks∞ at infinite dilution up to 200 105 Pa and 423 K is described. Measurements of the systems: (1) methane-ethane-n-decane and methane-propane-n-decane at 294.25 K; and (2) methane-n-butane-n-decane at 344.25 K illustrate the reproducibility and good agreement with literature data. In addition, new data were obtained for the system methane-n-pentane-n-decane at 344.25 K up to 101 105 Pa.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 29 (1983), S. 281-289 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: By considering reaction and diffusion through a product layer and concomitant movement of pore and reaction surfaces, a general rate equation is derived for fluid-solid reactions. Application to the random pore model extends the prior results (Bhatia and Perlmutter, 1980, 1981a) to account for nonlinear concentration gradients in the product layer, by assuming that the product is deposited as overlapping cylindrical annulae. For the Petersen (1957) model, new results are derived which account for product layer diffusion. A comparison of numerical conversion-time predictions from the grain model (Szekely et al., 1976), the Petersen model, and the random pore models suggests that they are more strongly affected by the representation of the reaction surface than by that of the pore surface. The model is applied to the data of Borgwardt (1970) on the SO2-lime reaction, and the results are compared with a previous interpretation using a linear concentration gradient approximation.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 29 (1983), S. 172-173 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 29 (1983), S. 806-812 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The reaction kinetics and physical transport processes governing the thermal dehydration of solid K2CO3·3/2H2O particles were investigated. Isothermal reaction rate data were gathered using a thermogravimetric balance in which narrowly-sized K2CO3·3/2H2O crystals were dehydrated under a water vapor atmosphere at different pressures and temperatures. The magnitudes of the heat and mass transfer resistances external to and within the solid product were estimated from solutions of the relevant pseudosteady-state transport equations. In the temperature range 320 to 358 K, the vacuum dehydration of K2CO3·3/2H2O crystals smaller than 710 μm (-25 +30 mesh) are accurately modeled by the spherical shrinking-core equation for the chemical rate control regime. In the presence of water vapor, external heat transfer to the particles was sufficient to prevent significant self-cooling; heat and mass transfer resistances within the particles were negligible. The activation energy for K2CO3·3/2H2O dehydration is approximately 91 kJ/mol in vacuum; the reaction becomes extremely slow at relative pressures (P/Peq) 〉 0.35.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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