Thermal treatment of superconductor thin film of the BSCCO system using domestic microwave oven

In this work, we report the preparation of a superconductor thin film of the BSCCO system using a good quality powder with nominal composition Bi_{1.8}Pb_{0.4}Sr_2CaCu_2O_x which was thermally treated using a domestic microwave oven (2.45 GHz, 800 W). This film was grew on a single crystal of LaAlO_3(100) substrate and exhibited a crystalline structure with the c-axis perpendicular to the plane of the substrate. An onset superconducting transition temperature was measured at 80 K.Comment: 4 pages, 5 figure

Zinc abundances in Galactic bulge field red giants: implications for DLA systems

Zinc in stars is an important reference element because it is a proxy to Fe in studies of damped Lyman-alpha systems, permitting a comparison of chemical evolution histories of bulge stellar populations and DLAs. In terms of nucleosynthesis, it behaves as an alpha element because it is enhanced in metal-poor stars. The aim of this work is to derive the iron-peak element Zn abundances in 56 bulge giants from high resolution spectra. These results are compared with data from other bulge samples, as well as from disk and halo stars, and damped Lyman-alpha systems, in order to better understand the chemical evolution in these environments. High-resolution spectra were obtained using FLAMES+UVES on the Very Large Telescope. We find [Zn/Fe]=+0.24+-0.02 in the range -1.3 < [Fe/H] < -0.5 and [Zn/Fe]=+0.06+-0.02 in the range -0.5 < [Fe/H] -0.1, it shows a spread of -0.60 < [Zn/Fe] < +0.15, with most of these stars having low [Zn/Fe]<0.0. These low zinc abundances at the high metallicity end of the bulge define a decreasing trend in [Zn/Fe] with increasing metallicities. A comparison with Zn abundances in DLA systems is presented, where a dust-depletion correction was applied for both Zn and Fe. Finally, we present a chemical evolution model of Zn enrichment in massive spheroids, representing a typical classical bulge.Comment: Accepted in Astronomy & Astrophysics, in press Date of acceptance: 13/05/2015. 19 pages, 14 Figs in Astronomy & Astrophysics, 201

Constriction size distributions of granular filters: a numerical study

The retention capability of granular filters is controlled by the narrow constrictions connecting the voids within the filter. The theoretical justification for empirical filter rules used in practice includes consideration of an idealised soil fabric in which constrictions form between co-planar combinations of spherical filter particles. This idealised fabric has not been confirmed by experimental or numerical observations of real constrictions. This paper reports the results of direct, particle-scale measurement of the constriction size distribution (CSD) within virtual samples of granular filters created using the discrete-element method (DEM). A previously proposed analytical method that predicts the full CSD using inscribed circles to estimate constriction sizes is found to poorly predict the CSD for widely graded filters due to an over-idealisation of the soil fabric. The DEM data generated are used to explore quantitatively the influence of the coefficient of uniformity, particle size distribution and relative density of the filter on the CSD. For a given relative density CSDs form a narrow band of similarly shaped curves when normalised by characteristic filter diameters. This lends support to the practical use of characteristic diameters to assess filter retention capability

Brave art: Scottish identity and stand-up comedy

Stand-up comedy remains a prevalent form of entertainment in Scotland, with comedians drawing sell-out crowds, and comedy making up the biggest section of the Edinburgh Fringe Festival programme. Moreover, stand-up comedy is recognised by many academics as a form of social commentary that can affirm or subvert cultural norms, or at the very least, provide a social thermometer that tells us what is going on in society. Research on Scottish stand-up comedy can therefore shed a light on how contemporary Scottish identity is constructed and understood. Yet, despite its popularity and potential social significance, few studies have focused on Scottish comedy to date, and none have chosen to analyse Scottish stand-up comedy specifically. The present research addresses this gap and uses discourse analysis to understand how Scottish stand-up comedy articulates representations of contemporary Scottish and British identities. The data for this study includes live comedy performances at the Edinburgh Fringe as well as interviews with stand-up comedians to gain a deeper insight. The findings show that Scotland is largely framed as a postcolonial nation with distinct values (inclusive, left-wing, egalitarian), particularly in comparison to ‘Brexit’ England. Despite this emphasis on civic nationalism, there are intersectional differences in how people experience Scottish identity, particularly for Scots positioned outside traditional white, heterosexual masculinity, who have to work harder to belong. The Edinburgh Fringe brings to the fore questions of belonging and exclusion as Scots make up a relatively small proportion of the comedy offering. Yet, the Fringe is also identified as a carnivalesque space with subversive potential. By disrupting the taken for granted, and highlighting possibilities for change, Scottish stand-up comedians at the Fringe engage in the political work of (de-)constructing the boundaries of identity and belonging