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  • Other Sources  (3)
  • ASTRONOMY  (2)
  • FLUID MECHANICS AND HEAT TRANSFER  (1)
  • Chemistry
  • 1985-1989  (3)
  • 1980-1984
  • 1965-1969
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  • 1
    Publication Date: 2019-06-28
    Description: Developing flows in two out-of-plane double S-bend configurations have been measured by laser-Doppler anemometry. The first duct had a rectangular cross-section 40mmx40mm at the inlet and consisted of a uniform area 22.5 deg. - 22.5 deg. S-duct upstream with a 22.5 deg.- 22.5 deg. S- diffuser downstream. The second duct had a circular cross-section and consisted of a 45 deg. - 45 deg. uniform area S-duct upstream with a 22.5 deg. -22.5 deg. S-diffuser downstream. In both configurations the ratio of the mean radius of curvature to the inlet hydraulic diameter was 7.0, the exit-to-inlet area ratio of the diffusers was 1.5 and the ducts were connected so that the centerline of the S-duct lay in a plane normal to that of the S-diffuser. Streamwise and cross-stream velocity components were measured in laminar flow for the rectangular duct and in turbulent flow for both configurations; measurements of the turbulence levels, cross-correlations and wall static pressures were also made in the turbulent flow cases. Secondary flows of the first kind are present in the first S-duct and they are complemented or counteracted by the secondary flows generated by the area expansion and by the curvature of the S-diffusers downstream. Cross-stream velocities with magnitudes up to 0.19 and 0.11 of the bulk velocity were measured in the laminar and turbulent flows respectively in the rectangular duct and six cross-flow vortices were evident at the exit of the duct in both flow cases. The turbulent flow in the circular duct was qualitatively similar to that in the rectangular configuration, but the cross-stream velocities measured at the exit plane were smaller in the circular geometry. The results are presented in sufficient detail and accuracy for the assessment of numerical calculation methods and are listed in tabular form for this purpose.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA-CR-176981 , NAS 1.26:176981 , FS/86/30
    Format: application/pdf
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  • 2
    Publication Date: 2019-07-12
    Description: This paper presents optical photometry and spectroscopy of SN 1987D, a Type Ia supernova in the nearby galaxy UGC 7370, during the period immediately subsequent to its discovery. The distance modulus of the galaxy, independently determined by the redshift and the Tully-Fisher (1977) relation, is 32.3 + or - 1.0. The maximum brightness of SN 1987D was V about 13.2 and occurred on April 18, 1987, + or - 4 days; the absolute luminosity is about 0.6 mag brighter than the average for SNe Ia. The spectrum of SN 1987D is typical of SNe Ia, but the expansion velocity (9600 km/s) is considerably lower than average.
    Keywords: ASTRONOMY
    Type: Astronomical Society of the Pacific, Publications (ISSN 0004-6280); 99; 1167-117
    Format: text
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  • 3
    Publication Date: 2019-07-12
    Description: Using the Einstein Observatory, X-ray observations of about 80 percent of the quasars in the Bright Quasar Survey located outside the declination range defined by 30 and 60 deg. X-ray emission has been detected above the 3-sigma level for 57 out of 66 quasars observed. This paper describes observations and data reduction and provides a summary of the more detailed analyses and discussion contained in the two accompanying papers (Schmidt and Green 1986, Avni and Tananbaum 1986).
    Keywords: ASTRONOMY
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 305; 57-67
    Format: text
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