27 research outputs found

    In Vulcan's Forge

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    Investigations on the correlations between glass and magma involving members of staff from the Glass Department at the University of Sunderland and volcanologists, Dr Fabian Wadsworth and Dr Ed Llewellin from the Natural Sciences Department of Durham University. From a physico-chemical perspective, both magmas and the hot glass manipulated by glass artists are one and the same. The proposed the research question; ‘what lessons can geoscientists learn from knowledge-exchange and experimentation with glass artists?

    The association of levels of physical activity with metabolic syndrome in rural Australian adults

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    Background:&nbsp; Physical activity (PA) reduces risk factors related to metabolic syndrome. Rurality influences the way people incorporate physical activity into daily life. The aim of this study is to determine the association of PA level with metabolic syndrome in a rural Australian population. The influence of adiposity on these associations is also investigated.Methods: Three cross-sectional population health surveys were conducted in south-east Australia during 2004&ndash;2006 using a random population sample (n = 1563, participation rate 49%) aged 25&ndash;74 years. PA was assessed via a self-administered questionnaire, and components of the metabolic syndrome via anthropometric measurements taken by specially trained nurses and laboratory tests.Results: Approximately one-fifth of participants were inactive in leisure-time and over one-third had metabolic syndrome (men 39%, women 33%; p = 0.022). There was an inverse association between level of PA and metabolic syndrome (p &lt; 0.001). Men who were inactive in leisure-time were more than twice as likely and women more than three times as likely to have metabolic syndrome compared with those having high PA. Body mass index (BMI) is a mediating factor in the association between level of PA and metabolic syndrome.Conclusion: Some PA is better than none if adults, particularly women, are to reduce their risk of metabolic syndrome and associated vascular diseases. Specialised interventions that take rurality into consideration are recommended for adults who are inactive.<br /

    Bubble rise in molten glasses and silicate melts during heating and cooling cycles

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    The Hadamard–Rybczynski equation describes the steady-state buoyant rise velocity of an unconfined spherical bubble in a viscous liquid. This solution has been experimentally validated for the case where the liquid viscosity is held constant. Here, we extend this result for non-isothermal conditions, by developing a solution for bubble position in which we account for the time-dependent liquid viscosity, liquid and gas densities, and bubble radius. We validate this solution using experiments in which spherical bubbles are created in a molten silicate liquid by cutting gas cavities into glass sheets, which are stacked, then heated through the glass transition interval. The bubble-bearing liquid, which has a strongly temperature-dependent viscosity, is subjected to various heating and cooling programs such that the bubble rise velocity varies through the experiment. We find that our predictions match the final observed position of the bubble measured in blocks of cooled glass to within the experimental uncertainty, even after the application of a complex temperature–time pathway. We explore applications of this solution for industrial, artistic, and natural volcanological applied problems
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