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  • 1
    Electronic Resource
    Electronic Resource
    Highlights from the COMPTEL 1 to 30 MeV Sky Survey (1995)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 759 (1995), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1995.tb17533.x
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  • 2
    Electronic Resource
    Electronic Resource
    Distribution of cosmic-ray electrons in the Galaxy (1980)
    [s.l.] : Nature Publishing Group
    Nature 287 (1980), S. 810-812 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Using y-ray data to find the distribution of cosmic rays has long been considered; for example, Dodds et a/.1 have reviewed the distribution of a mixed proton-electron component from analysis of y rays above lOOMeV towards the galactic anticentre. Here, SAS 2 satellite data2"4 is used in the energy ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/287810a0
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  • 3
    Electronic Resource
    Electronic Resource
    Drag coefficients of spherical liquid droplets Part 2: Turbulent gaseous fields (1995)
    Springer
    Experiments in fluids 18 (1995), S. 265-276 
    Details
    ISSN: 1432-1114
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The drag of non-evaporating, spherical, liquid droplets was measured in turbulent flow fields at parametric ranges relevant to spray combustion, characterized by the droplet Reynolds number, and the intensity and spatial scales of turbulence. The experimental apparatus comprised a wind-tunnel and a piezo-electric droplet generator. The procedure was to inject water droplets of uniform size co-currently and continuously with vertical turbulent air flows while droplet velocity was measured at different elevations using laser-Doppler velocimetry. Turbulence was characterized using hot-wire anemometry prior to droplet injection. Drag coefficients were calculated using these main measurements and the law of conservation of mechanical energy. Reynolds numbers were investigated in the range 10–100, in terms of the equivalent spherical diameter of a droplet, and the mean relative speed between the ambient gaseous field and the droplets. Weber numbers were much less than unity so droplets were effectively spherical. Relative intensities of turbulence were investigated in the range 20–65 percent, in terms of the mean relative speed. Spatial scales of turbulence were large in comparison to the droplets; the ratio between the spatial integral scale and the droplet diameter was in the range 11–38, and the Kolmogorov scale was comparable in size or smaller than the droplet diameter. Experimental data showed that the drag in turbulent fields under these conditions is not significantly different than that of solid spheres in a quiescent field at the same Reynolds number.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00195097
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  • 4
    Electronic Resource
    Electronic Resource
    Drag coefficients of spherical liquid droplets Part 1: Quiescent gaseous fields (1995)
    Springer
    Experiments in fluids 18 (1995), S. 258-264 
    Details
    ISSN: 1432-1114
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The drag coefficient of non-evaporating, spherical, liquid droplets in quiescent gaseous fields is measured using a novel experimental methodology at Reynolds numbers from 20 to 120. The experimental uncertainties are typically less than 8 percent, and the results are on average within 6 percent of the drag coefficient of liquid and rigid spheres, based on an accepted relationship. The methodology described in this article is therefore validated so it can be extended with confidence to measurements in turbulent gaseous fields.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00195096
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  • 5
    Electronic Resource
    Electronic Resource
    Maximum Entropy imaging of comptel data (1995)
    Springer
    Experimental astronomy 6 (1995), S. 97-102 
    Details
    ISSN: 1572-9508
    Keywords: gamma-ray astronomy ; image processing ; maximum entropy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The Maximum Entropy method is a practical technique for generating intensity skymaps from Compton-telescope data. The application of the method to COMPTEL data for point sources and large-scale emission is described. New developments in the method are illustrated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00419263
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  • 6
    Electronic Resource
    Electronic Resource
    The use of gamma rays to trace the local interstellar hydrogen (1983)
    Springer
    Space science reviews 36 (1983), S. 267-272 
    Details
    ISSN: 1572-9672
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract COS-B data in the latitude range 11° 〈¦b¦ 〈 19° show the gamma-ray intensity to be closely correlated with the total line-of-sight absorption derived from galaxy counts. It is found that to a good approximation the gamma-ray intensity is proportional to the total gas column density, and on this basis a map of the angular distribution of local molecular hydrogen at intermediate latitudes is presented. Comparing this with a simular map produced from galaxy counts, several structures appear in both maps in regions related to Gould's Belt and elsewhere. Some regions in the Southern celestial hemisphere not accessible in galaxy counts show high molecular hydrogen column densities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00247091
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  • 7
    Electronic Resource
    Electronic Resource
    Diffuse galactic gamma-ray continuum emission (1996)
    Springer
    Space science reviews 76 (1996), S. 205-230 
    Details
    ISSN: 1572-9672
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Some of the most important questions about the diffuse gamma-ray continuum emission from the Galaxy are reviewed, based on Compton Observatory (CGRO) results, especially COMPTEL and EGRET, and also earlier COS-B analyses. The key issues include the rôle of emission from cosmic-ray interactions with molecular hydrogen and its energy dependence, emissivity gradients and their interpretation, the cosmic-ray electron spectrum and the effect of discrete sources. The relative contribution of the various emission processes at low and high latitudes is estimated and a plausible synthesis of the observed spectrum over 5 decades of energy is presented. In the energy range above 30 MeV, models based either on explicit cosmic-ray gradients or cosmic-ray/gas coupling can give acceptable fits to the data, and a clear distinction has yet to be made. The quality of the EGRET data may make this possible in the future. The value of the CO-to-H2 conversion factor from γ-rays is still uncertain and there is considerable evidence for cloud-to-cloud variations. The existence of a small emissivity gradient is well established, but is difficult to explain in a diffusive cosmic-ray propagation picture with sources distributed like SNR or pulsars unless there is a larger halo than suggested by cosmic-ray composition studies. In the energy range 1–30 MeV covered by COMPTEL the spectrum of the diffuse emission has been measured and is consistent with a combination of bremsstrahlung and inverse-Compton emission; spatial analysis shows strong evidence for a component with a wide latitude extent which is plausibly identified with the inverse-Compton component. The molecular hydrogen appears to be only a weak γ-ray emitter at low energies, which can be interpreted in terms of reduced MeV cosmic-ray electron density in molecular clouds. New data on the hard X-ray diffuse galactic emission is becoming available and indicates the need for a low-energy upturn in the electron spectrum or some other additional component. The contribution of unresolved sources to the ‘diffuse’ emission is unknown but-probably lies in the range 10–20%. At high latitudes the galactic emission is intense enough to significantly complicate the identification of the extragalactic component; in particular the inverse-Compton emission from a halo a few kpc in extent can account for much of the high-latitude galactic emission. The detection of the Large Magellanic Cloud and the non-detection of the Small Magellanic Cloud provide constraints on extragalactic cosmic-rays, and provide an interesting comparison with the properties of the galactic system. On account of the large amount of data from CGRO now available, this is a subject in rapid development, and this paper provides a snapshot of the situation around mid-1995.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00197840
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  • 8
    Electronic Resource
    Electronic Resource
    Numerical predictions of flows over backward-facing steps (1984)
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 4 (1984), S. 711-724 
    Details
    ISSN: 0271-2091
    Keywords: Finite-Volume Method ; Numerical Diffusion ; Upstream Weighted Differencing ; Skew Upstream Differencing ; Turbulent Recirculating Flow ; Turbulence Model ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Predictions are reported for two-dimensional, steady, incompressible flows over rearward-facing steps for both laminar and turbulent conditions. The standard k-∊ turbulence model was used for the turbulent flow. Attention was focused on obtaining accurate solutions to the differential equations. It is concluded that some of the serious discrepancies that have occurred between prediction and observation, and attributed in earlier studies to the inadequacy of the turbulence model, may have been due to the inaccuracy of the solution.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/fld.1650040802
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  • 9
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    Drag coefficients of spherical liquid droplets Part 2: Turbulent gaseous fields (1995)
    Springer
    Details
    Publication Date: 1995-02-01
    Print ISSN: 0723-4864
    Electronic ISSN: 1432-1114
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Springer
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  • 10
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    Drag coefficients of spherical liquid droplets Part 1: Quiescent gaseous fields (1995)
    Springer
    Details
    Publication Date: 1995-02-01
    Print ISSN: 0723-4864
    Electronic ISSN: 1432-1114
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Springer
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