826 research outputs found

    FROM ART TO THE EVERYDAY: ROBIN BOYD AND THE 'WINDOWWALL'

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    Throughout his career, Australian architect and critic Robin Boyd (1919-1971) explored alternatives for the orthodox elements of architecture. Using the laboratory-scale of the detached house, Boyd would rethink wall, roof, floor and window. He was interested in making such elements serve more than one function. He wanted to rationalise the architectural palette with the hope that his invented elements might develop new formal meaning, and hence potential acceptance at a broader professional and popular level. An early target of Boyd's design research was the combination of window and wall, culminating in 1952-53 with the patented Stegbar 'Windowall', a modular structural window framing system that was to have national application across the full breadth of Australian domestic architecture from the 1950s to the 1970s. Neil Clerehan has observed that, “It was with the Windowall that Boyd, more than any other single architect, gave our suburbs a distinctive look. Even Palladio couldn't do that. The Stegbar victory was his greatest triumph. His Windowalls were an intrinsic look of the fifties” (60). This paper follows the development of Boyd's window-wall, from his earliest known projects in the late 1930s to unique custom-designed solutions, and in parallel the industrial application of his ideas that would give direction to his own project house designs, and subsequently influence the appearance of the typical suburban home. It will be shown that this process was one of transformation: in a characteristically modernist displacement, Boyd transformed the window of the artist's studio to become a structural glazed frame for the everyday Australian living room (Colquhoun 51)

    A universal GRB photon energy-peak luminosity relation

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    The energetics and emission mechanism of GRBs are not well understood. Here we demonstrate that the instantaneous peak flux or equivalent isotropic peak luminosity, L_iso ergs s^-1, rather than the integrated fluence or equivalent isotropic energy, E_iso ergs, underpins the known high-energy correlations. Using new spectral/temporal parameters calculated for 101 bursts with redshifts from BATSE, BeppoSAX, HETE-II and Swift we describe a parameter space which characterises the apparently diverse properties of the prompt emission. We show that a source frame characteristic-photon-energy/peak luminosity ratio, K_z, can be constructed which is constant within a factor of 2 for all bursts whatever their duration, spectrum, luminosity and the instrumentation used to detect them. The new parameterization embodies the Amati relation but indicates that some correlation between E_peak and E_iso follows as a direct mathematical inference from the Band function and that a simple transformation of E_iso to L_iso yields a universal high energy correlation for GRBs. The existence of K_z indicates that the mechanism responsible for the prompt emission from all GRBs is probably predominantly thermal.Comment: Submitted to Ap

    Removal of spacecraft-surface particulate contaminants by simulated micrometeoroid impacts

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    A series of hypervelocity impacts has been conducted in an exploding lithium-wire accelerator to examine with a far-field holographic system the removal of particulate contaminants from external spacecraft surfaces subjected to micrometeoroid bombardment. The impacting projectiles used to simulate the micrometeoroids were glass spheres nominally 37 microns in diameter, having velocities between 4 and 17 km/sec. The particulates were glass spheres nominally 25, 50, and 75 microns in diameter which were placed on aluminum targets. For these test, particulates detached had velocities that were log-normally distributed. The significance of the log-normal behavior of the ejected-particulate velocity distribution is that the geometric mean velocity and the geometric standard deviation are the only two parameters needed to model completely the process of particles removed or ejected from a spacecraft surface by a micrometeoroid impact

    New insights into ultraluminous X-ray sources from deep XMM-Newton observations

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    The controversy over whether ultraluminous X-ray sources (ULXs) contain a new intermediate-mass class of black holes (IMBHs) remains unresolved. We present new analyses of the deepest XMM-Newton observations of ULXs that address their underlying nature. We examine both empirical and physical modelling of the X-ray spectra of a sample of thirteen of the highest quality ULX datasets, and find that there are anomalies in modelling ULXs as accreting IMBHs with properties simply scaled-up from Galactic black holes. Most notably, spectral curvature above 2 keV in several sources implies the presence of an optically-thick, cool corona. We also present a new analysis of a 100 ks observation of Holmberg II X-1, in which a rigorous analysis of the temporal data limits the mass of its black hole to no more than 100 solar masses. We argue that a combination of these results points towards many (though not necessarily all) ULXs containing black holes that are at most a few 10s of solar mass in size.Comment: 5 pages, 2 figures, to appear in the proceedings of "The X-ray Universe 2005", San Lorenzo de El Escorial (Spain), 26-30 September 200

    Does Every Quasar Harbor A Blazar?

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    Assuming there is a blazar type continuum in every radio-loud quasar, we find that the free-free heating due to the beamed infrared continuum can greatly enhance collisionally excited lines, and thus explain the stronger CIV λ\lambda1549 line emission observed in radio loud quasars. We further predict that the CIV line should show variability {\it not} associated with observed continuum or Lyα\alpha variability.Comment: 15 pages, 3 figures; to appear in Astrophys. J. Let

    A Guide to the California Immunization Registry and Its Use to Enhance the Delivery of Immunization Services

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    Pharmacists in California are assuming a greater role as independent providers of immunizations for children and adults under Senate Bill 493 (SB 493). One of the requirements for pharmacists as independent providers of immunizations in California is that they must report their administered doses to the California immunization registry system (CAIR). The National Vaccine Advisory Committee Standards for Immunization Practice also supports this practice by recommending that all immunizing providers report vaccinations to their local and state immunization information systems (IIS). This document presents background and specific features of CAIR; best practice recommendations for the use of IIS lookup, forecasting, follow-up, and recall; and documentation features to enhance the delivery of immunization services

    Locally Optimally Emitting Clouds and the Origin of Quasar Emission Lines

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    The similarity of quasar line spectra has been taken as an indication that the emission line clouds have preferred parameters, suggesting that the environment is subject to a fine tuning process. We show here that the observed spectrum is a natural consequence of powerful selection effects. We computed a large grid of photoionization models covering the widest possible range of cloud gas density and distance from the central continuum source. For each line only a narrow range of density and distance from the continuum source results in maximum reprocessing efficiency, corresponding to ``locally optimally-emitting clouds'' (LOC). These parameters depend on the ionization and excitation potentials of the line, and its thermalization density. The mean QSO line spectrum can be reproduced by simply adding together the full family of clouds, with an appropriate covering fraction distribution. The observed quasar spectrum is a natural consequence of the ability of various clouds to reprocess the underlying continuum, and can arise in a chaotic environment with no preferred pressure, gas density, or ionization parameter.Comment: 9 pages including 1 ps figure. LaTeX format using aaspp4.st
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