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  • 1
    ISSN: 0273-1177
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0273-1177
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0273-1177
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Journal of Chromatography A 247 (1982), S. 205-210 
    ISSN: 0021-9673
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Astrophysics and space science 169 (1990), S. 223-225 
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Limb-darkening coefficients for a grid of LTE, non-grey atmosphere models has been calculated by means of Upsalla Model Atmosphere (UMA) code using a least-squares fitting. Both linear and quadratic laws were adopted in the standard models and in those with irradiation from a companion, star as well, more realistic for the case of close binaries.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Astrophysics and space science 169 (1990), S. 215-217 
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The radius of gyration of Main-Sequence stars is an important parameter in studies of circularization and synchronization of close binaries. We present new values calculated, on the basis of updated models of stellar structure with the latest opacity tables. The importance of evolution in calculating moments of inertia is emphasized. Our results are presented in such a way that they can be directly used to compare theoretical predictions with actual observations.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Astrophysics and space science 193 (1992), S. 185-200 
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract This study compares computational results from stellar models and the evolutive behaviour of the stars, using elements of Jacobi dynamics. A linearized form of the Jacobi equation is used in order to analyze the dependency on the time of the coefficients α(t), β(t) of the inner structure of the stars. With these coefficients and the stellar radiiR(t) one can define all the dynamical parameters: the potential energyE p(t), the momentum of inertiaI(t), the Jacobi function ϕ(t), and the amount of actionA c(t), and the relations among them depending on the geometry of the problem. The computational models used here include pre-Main-Sequence stages and variations in the chemical compositionX, Z. Since this is an introductory study, we only used the examples for 5M ⊙, 1M ⊙, and 0.6⊙. The results obtained are: (a) The Main Sequence represents a state of minimum action and potential energy whereA c(t) andE p(t) are nearly invariant when compared to the variations of any other stellar parameter such as luminosityL(t), radiusR(t), or the density ρ(t) on which depends α(t), β(t). (b) These parameters and the time of permanence of a star in the Main Sequence are, as expected, very sensitive toX, Z. But the parametersA c, Ep remain minimum and nearly invariant in the Main Sequence. The contractive and expansive phases associated with the pre-and post-Main-Sequence stages are also analysed. The scenario is not fundamentally altered if one includes rotational effects, taking the possible upper limits from observed rotations in T Tauri stars. (c) As a test for the theoretical criteria used here (and as a by-product with further applications) one has that the effective dynamical density ρeff=α3ρ (mean stellar density) leads to an effective scale time for the thermal motions in the stellar interiorP eff∝ ρ eff −1/2 which is consistent with oscillation periods of pulsating stars not far from the Main Sequence such as δ Scuti and β Cephei. The possibilities of further studies about stellar evolution using Jacobi dynamics are discussed.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Astrophysics and space science 193 (1992), S. 235-246 
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The stars in the Main Sequence are seen as a hierarchy of objects with different massesM and effective dynamical radiiR eff=R/α given by the stellar radii and the coefficients for the inner structure of the stars. As seen in a previous work (Paper I), during the lifetime in the Main SequenceR eff(t) remains a near invariant when compared to the variation in the time ofR(t) and α(t). With such an effectiveR eff one obtains the amounts of actionA c(M), the effective densities ρeff(M)=ρ(M)α3(M), the densities of action and of energy (or mean presures in the stellar interior)a c(M),e c(M), and the potential energiesE p(M). The amounts of action areA c∝M k withk≈1.87 for the M stars,k≈5/3 for the KGF stars, andk≈1.83 for the A and earlier stars, representing very simples conditions for the other dynamical parameters. For instancek≈5/3 means a near invariant effective density αeff for the KGF stars, while for such stars the mean densities and coefficients α present the strongest variations with masses ρ(M)∝M −1.81, α(M)∝M0.6. The cases for the M stars (e c(M)∝M −1) and for the A and earlier stars (betweena c(M)=constant and αeff(M)∝M −1) and also discussed. These conditions for the earlier stars also represent reasonable mean values for the whole stellar hierarchy in the range of masses 0.2M ⊙≤M≤25M ⊙. With all this, one can build ‘dynamical’ HR diagrams withA c(M), Ep(M), αeff M −p , etc., whose characteristics are analogous to these in the photometrical HR diagram. A comparison is made betweenA c(M) from the models here and the HR diagram with the best known stars of luminosity classes IV, V, and white dwarfs. The comparison of the potential energiesE p(M)∝M −p according to the stellar models used here and the observed frequency function ψ(M∝M −q (number of stars in a given interval of masses) from different authors suggests the possibility that the productE p(M)ψ(M) is a constant, but this must be confirmed with further studies of the function ψ(M) and its fine structure. There are analogies between the formulation used here for the stellar hierarchy and other physical processes, for instance, in modified forms of the Kolmogorov law of turbulence and in the formulation used for the hierarchy of molecular clouds in gravitational equilibrium. Besides, the function of actionA c(M) for the stars has analogous properties to the relations of angular momenta and massesJ(M) for different types of objects. The cosmological implications of all this are discussed.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Experimental astronomy 10 (2000), S. 305-318 
    ISSN: 1572-9508
    Keywords: cosmic ray effects ; glitch removal methods ; ISO spacecraft
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract One of the main limitations to the sensitivity of observations carried out withthe ISOCAM infrared camera comes from the responsivity variations and glitchescaused by impacts of charged particles. After more than 28 months of successfuloperations, the predicted glitch rate has been re-evaluated and compared toin-flight measurements. Glitch properties have been studied in orderto improve the removal algorithms, and thus the ultimate sensitivity of ISOCAM.All informations about the glitch phenomenon are very useful in order toprepare next space experiments.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Experimental astronomy 10 (2000), S. 279-290 
    ISSN: 1572-9508
    Keywords: cosmic ray effects ; delta rays ; ISO spacecraft ; secondary particles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The ISOCAM detector is subjected to transient effects induced bycosmic rays, the so-called glitches. This paper is focused onthe ISOCAM long wave detector. The predicted glitch rates havebeen re-evaluated by taking into account secondary particlesproduction in the materials surrounding the LW detector. We showin this preliminary study that the difference between thepreviously predicted glitch rate and the observed rate may beexplained by secondary particles.
    Type of Medium: Electronic Resource
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