1,164 research outputs found
Transient and Quasi-Steady Thermal Behaviour of a Building Envelope due to Retrofitted Cavity Wall and Ceiling Insulation
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
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 , with
. The solution exhibits a singularity at the origin. If we assume
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 . 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 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
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
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
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
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
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
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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