6,149 research outputs found

    ΔI=4\Delta I=4 and ΔI=8\Delta I=8 bifurcations in rotational bands of diatomic molecules

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    It is shown that the recently observed ΔI=4\Delta I=4 bifurcation seen in superdeformed nuclear bands is also occurring in rotational bands of diatomic molecules. In addition, signs of a ΔI=8\Delta I=8 bifurcation, of the same order of magnitude as the ΔI=4\Delta I=4 one, are observed both in superdeformed nuclear bands and rotational bands of diatomic molecules.Comment: LaTex twice, 10 pages and 5 PS figures provided upon demand by the Author

    Star Clusters in the Magellanic Clouds-1: Parameterisation and Classification of 1072 Clusters in the LMC

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    We have introduced a semi-automated quantitative method to estimate the age and reddening of 1072 star clusters in the Large Magellanic Cloud (LMC) using the Optical Gravitational Lensing Experiment (OGLE) III survey data. This study brings out 308 newly parameterised clusters. In a first of its kind, the LMC clusters are classified into groups based on richness/mass as very poor, poor, moderate and rich clusters, similar to the classification scheme of open clusters in the Galaxy. A major cluster formation episode is found to happen at 125 +- 25 Myr in the inner LMC. The bar region of the LMC appears prominently in the age range 60 - 250 Myr and is found to have a relatively higher concentration of poor and moderate clusters. The eastern and the western ends of the bar are found to form clusters initially, which later propagates to the central part. We demonstrate that there is a significant difference in the distribution of clusters as a function of mass, using a movie based on the propagation (in space and time) of cluster formation in various groups. The importance of including the low mass clusters in the cluster formation history is demonstrated. The catalog with parameters, classification, and cleaned and isochrone fitted CMDs of 1072 clusters, which are available as online material, can be further used to understand the hierarchical formation of clusters in selected regions of the LMC.Comment: 19 pages, 19figures, published in MNRAS on August 16, 2016 Supplementary material is available in the MNRAS websit

    Pit Slope Failure Problems in Goan Iron Ore Mines, Goa, India

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    The problem of open pit slope stability is a matter of concern when the mining operations go deeper followed by weak strata conditions. In Goa iron ore mines the problem of slope instability has been faced by several mines, after the on-set of monsoon. A review of case studies available on the subject demonstrates that the ground displacement, stress redistribution, effect of ground water, low strength characteristics of the slope forming materials played significant role for the cause of slope failures. Slope monitoring studies indicated that the mechanism of slope failures could be complex and dependent on failure pathways, where certain units fail first and it is followed by subsequent failures due to redistribution of stresses from the preceding zone. The results of several observations, laboratory testing of slope forming materials and monitoring of the slopes have lead to an awareness of various mechanisms of failure and the conditions under which they occur. In real world situations, the failure mechanisms are much more complex involving many other variables due to complexity within the geological materials. The paper addressed the design of practical pit slope angles in such type of weak strata conditions. The testing techniques for material properties enable weak zones to be identified and their relative strengths are accurately determined. Case study of a large Iron mine discussed in detail to demonstrate how deep mining can be carried out under difficult ground conditions

    Molecular theory of elastic constants of liquid crystals. III. Application to smectic phases with tilted orientational order

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    Using the density functional formalism we derive expression for the distortion free energy for systems with continuous broken symmetry and use it to derive expression for the elastic constants of smectic phases in which director is tilted with respect to the smectic layer normal. As in the previous papers of the series (Phys. Rev. A {\bf 45}, 974 (1992), E {\bf 49}, 501, (1994)) the expressions for the elastic constants are written in terms of order and structural parameters. The structural parameters involve the generalised spherical harmonic coefficients of the direct pair correlation function of an effective isotropic liquid. The density of this effective isotropic liquid depends on the nature and amount of ordering present in the system and is evaluated self- consistently. We estimate the value of elastic constants using reasonable guess for the order and structural- parameters.Comment: 31 pages; 1 Fig. in GIF format, To be appear in Phys. Rev.

    Fluids of hard ellipsoids: Phase diagram including a nematic instability from Percus-Yevick theory

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    An important aspect of molecular fluids is the relation between orientation and translation parts of the two-particle correlations. Especially the detailed knowledge of the influence of orientation correlations is needed to explain and calculate in detail the occurrence of a nematic phase. The simplest model system which shows both orientation and translation correlations is a system of hard ellipsoids. We investigate an isotropic fluid formed of hard ellipsoids with Percus-Yevick theory. Solving the Percus-Yevick equations self-consistently in the high density regime gives a clear criterion for a nematic instability. We calculate in detail the equilibrium phase diagram for a fluid of hard ellipsoids of revolution. Our results compare well with Monte Carlo Simulations and density functional theory.Comment: 7 pages including 4 figure

    Absence of ferromagnetism in Co and Mn substituted polycrystalline ZnO

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    We discuss the properties of semiconducting bulk ZnO when substituted with the magnetic transition metal ions Mn and Co, with substituent fraction ranging from xx = 0.02 to xx = 0.15. The magnetic properties were measured as a function of magnetic field and temperature and we find no evidence for magnetic ordering in these systems down to TT = 2 K. The magnetization can be fit by the sum of a Curie-Weiss term with a Weiss temperature of Θ\Theta\gg100 K and a Curie term. We attribute this behavior to contributions from both \textit{t}M ions with \textit{t}M nearest neighbors and from isolated spins. This particular functional form for the susceptibility is used to explain why no ordering is observed in \textit{t}M substituted ZnO samples despite the large values of the Weiss temperature. We also discuss in detail the methods we used to minimize any impurity contributions to the magnetic signal.Comment: 6 pages, 4 figures (revised
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