1,164 research outputs found

    Transient and Quasi-Steady Thermal Behaviour of a Building Envelope due to Retrofitted Cavity Wall and Ceiling Insulation

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    Accurate understanding of the thermal behaviour of building components is essential for predicting heat-ing or cooling needs and facilitates the implementation of more successful energy saving strategies and retrofits. This paper focuses on a specific measure commonly introduced through the residential energy efficiency retrofit programmes in Ireland–insulation. Traditionally, assessments of the performance of building envelopes have been based on assumed thermal resistances of the materials involved, labora-tory tests and computer modelling. The aim of the present work is to investigate the in situ thermal behaviour of a case study building and its components under transient and quasi-steady environmental conditions, comparing data before and after the fixing of cavity wall and ceiling insulation. The paper concludes by proposing that predicted values of heat loss using standardised assumed material prop-erties of the existing structure do not reflect the actual values achieved in situ for this test case. These values greatly overestimated the impact of the retrofitted insulation on heat loss through the ceiling and wall

    The self-screening Hawking atmosphere

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    A model is proposed in which the Hawking particles emitted by a black hole are treated as an envelope of matter that obeys an equation of state, and acts as a source in Einstein's equations. This is a crude but interesting way to accommodate for the back reaction. For large black holes, the solution can be given analytically, if the equation of state is p=κρp=\kappa\rho, with 0<κ<10<\kappa<1. The solution exhibits a singularity at the origin. If we assume NN free particle types, we can use a Hartree-Fock procedure to compute the contribution of one such field to the entropy, and the result scales as expected as 1/N1/N. A slight mismatch is found that could be attributed to quantum corrections to Einstein's equations, but can also be made to disappear when \k is set equal to one. The case κ=1\kappa=1 is further analysed.Comment: 19 pages, plain TeX, 5 figures PostScript. The author was made aware of further references to older work, in view of which modifications were made in order to avoid too much overlap. A discussion is added on the case $\kappa=1

    Io's polar volcanic thermal emission indicative of magma ocean and shallow tidal heating models

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    The distribution of Io's volcanic activity likely reflects the position and magnitude of internal tidal heating. We use new observations of Io's polar regions by the Juno spacecraft Jovian Infrared Auroral Mapper (JIRAM) to complete near-infrared global coverage, revealing the global distribution and magnitude of thermal emission from Io's currently erupting volcanoes. We show that the distribution of volcanic heat flow from 266 active hot spots is consistent with the presence of a global magma ocean, and/or shallow asthenospheric heating. We find that Io's polar volcanoes are less energetic but about the same in number per unit area than at lower latitudes. We also find that volcanic heat flow in the north polar cap is greater than that in the south. The low volcanic advection seen at Io's poles is therefore at odds with measurements of background temperature showing Io's poles are anomalously warm. We suggest that the differences in volcanic thermal emission from Io's poles compared to that at lower latitudes is indicative of lithospheric dichotomies that inhibit volcanic advection towards Io's poles, particularly in the south polar region.Comment: 17 pages, two tables, 7 figure

    Gerry Downey: an authentic spectroscopist

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    This year has seen the retirement of Gerry Downey from active service with the Irish National Agriculture and Food Research Institute, Teagasc1 in Dublin. As one of Europe’s leading innovative spectroscopic chemometricians and a great positive personality to have as a project partner, we thought it appropriate to dedicate a column to Gerry’s career, however embarrassed he may be about the idea

    The causal effects of education on health outcomes in the UK Biobank

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    Educated people are generally healthier, have fewer comorbidities and live longer than people with less education 1-3. Much of the evidence about the effects of education comes from observational studies, which can be affected by residual confounding. Natural experiments, such as laws that increase the minimum school leaving age, are a potentially more robust source of evidence about the causal effects of education. Previous studies have exploited this natural experiment using population-level administrative data to investigate mortality, and surveys to investigate the effect on morbidity 1, 2,4. Here, we add to the evidence using data from a large sample from the UK Biobank 5. We exploit the raising of the minimum school leaving age in the UK in September 1972 as a natural experiment 6. We used a regression discontinuity design to investigate the causal effects of remaining in school. We found consistent evidence that remaining in school causally reduced the risk of diabetes and mortality in all specifications. </p

    Discovery of a luminous white dwarf in a young star cluster in the Large Magellanic Cloud

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    We have identified a candidate 1-2 x 10^5 year old luminous white dwarf in NGC 1818, a young star cluster in the Large Magellanic Cloud. This discovery strongly constrains the boundary mass M_c at which stars stop forming neutron stars and start forming white dwarfs, to M_c > 7.6 Msun.Comment: 4 pages, 2 figures, greyscale image available by ftp from [email protected]. ApJLetters, accepted 17 March 199

    The causal effects of education on adult health, mortality and income: evidence from Mendelian randomization and the raising of the school leaving age

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    BACKGROUND: On average, educated people are healthier, wealthier and have higher life expectancy than those with less education. Numerous studies have attempted to determine whether education causes differences in later health outcomes or whether another factor ultimately causes differences in education and subsequent outcomes. Previous studies have used a range of natural experiments to provide causal evidence. Here we compare two natural experiments: a policy reform, raising the school leaving age in the UK in 1972; and Mendelian randomization. METHODS: We used data from 334 974 participants of the UK Biobank, sampled between 2006 and 2010. We estimated the effect of an additional year of education on 25 outcomes, including mortality, measures of morbidity and health, ageing and income, using multivariable adjustment, the policy reform and Mendelian randomization. We used a range of sensitivity analyses and specification tests to assess the plausibility of each method's assumptions. RESULTS: The three different estimates of the effects of educational attainment were largely consistent in direction for diabetes, stroke and heart attack, mortality, smoking, income, grip strength, height, body mass index (BMI), intelligence, alcohol consumption and sedentary behaviour. However, there was evidence that education reduced rates of moderate exercise and increased alcohol consumption. Our sensitivity analyses suggest that confounding by genotypic or phenotypic confounders or specific forms of pleiotropy are unlikely to explain our results. CONCLUSIONS: Previous studies have suggested that the differences in outcomes associated with education may be due to confounding. However, the two independent sources of exogenous variation we exploit largely imply consistent causal effects of education on outcomes later in life

    Creating the right 'vibe': Exploring the utilisation of space at Hip Hop concerts in Adelaide and Melbourne

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    This chapter examines how space is utilised at Hip Hop concerts to promote certain sensual experiences. It is based on ethnographic fieldwork conducted in the Adelaide and Melbourne Hip Hop scenes. I explore how light, sound, venue layout and spacing are harnessed to foster specific reactions from the crowd and to create what Hip Hop fans colloquially referred to as the 'vibe'. I conclude that the practical realities of particular venue spaces (size, configuration, stage equipment and so on) can significantly influence the experiences of individuals attending Hip Hop concerts and the presence or absence of the 'vibe'.Dianne Rodge
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