1,047 research outputs found
Low carbon housing: lessons from Elm Tree Mews
This report sets out the findings from a low carbon housing trial at Elm Tree Mews, York, and discusses the technical and policy issues that arise from it. The Government has set an ambitious target for all new housing to be zero carbon by 2016. With the application of good insulation, improved efficiencies and renewable energy, this is theoretically possible. However, there is growing concern that, in practice, even existing carbon standards are not being achieved and that this performance gap has the potential to undermine zero carbon housing policy. The report seeks to address these concerns through the detailed evaluation of a low carbon development at Elm Tree Mews. The report: * evaluates the energy/carbon performance of the dwellings prior to occupation and in use; * analyses the procurement, design and construction processes that give rise to the performance achieved; * explores the resident experience; * draws out lessons for the development of zero carbon housing and the implications for government policy; and * proposes a programme for change, designed to close the performance gap
Airtightness of buildings — towards higher performance: Final Report — Domestic Sector Airtightness
This report constitutes milestone D11 — Final Report — Domestic Sector Airtightness of the Communities and Local Government/ODPM Project reference CI 61/6/16 (BD2429) Airtightness of Buildings — Towards Higher Performance (Borland and Bell, 2003). This report presents the overall conclusions and key messages obtained from the project through design assessments, construction observations, discussions with developers and pressurisation test results. It also summarises discussion on the airtight performance of current UK housing, the implementation and impact of current and future legislation, and identifies potential areas for future work
Influence of crystal structure on charge carrier effective masses in BiFeO
Ferroelectric-based photovoltaics have shown great promise as a source of
renewable energy, thanks to their in-built charge separation capability, yet
their efficiency is often limited by low charge carrier mobilities. In this
work, we compare the photovoltaic prospects of various phases of the
multiferroic material BiFeO by evaluating their charge carrier effective
masses using first-principles simulations. We identify a tetragonal phase with
the promising combination of a large spontaneous polarisation and relatively
light charge carriers. From a systematic study of the octahedral distortions
present in BiFeO, we explain the relationship between structure and
effective masses in terms of the changes to the orbital character and overlap
at the band edges that result from changes in the geometry. The findings in
this study provide some design principles to engineer desired effective masses
in BiFeO and similar materials through manipulation of their crystal
structures in experimentally accessible ways.Comment: 12 pages, 10 figure
Stochastic models in population biology and their deterministic analogs
In this paper we introduce a class of stochastic population models based on
"patch dynamics". The size of the patch may be varied, and this allows one to
quantify the departures of these stochastic models from various mean field
theories, which are generally valid as the patch size becomes very large. These
models may be used to formulate a broad range of biological processes in both
spatial and non-spatial contexts. Here, we concentrate on two-species
competition. We present both a mathematical analysis of the patch model, in
which we derive the precise form of the competition mean field equations (and
their first order corrections in the non-spatial case), and simulation results.
These mean field equations differ, in some important ways, from those which are
normally written down on phenomenological grounds. Our general conclusion is
that mean field theory is more robust for spatial models than for a single
isolated patch. This is due to the dilution of stochastic effects in a spatial
setting resulting from repeated rescue events mediated by inter-patch
diffusion. However, discrete effects due to modest patch sizes lead to striking
deviations from mean field theory even in a spatial setting.Comment: 47 pages, 9 figure
Recommended from our members
Magnetic Resonance Imaging Pilot Study of Intravenous Glyburide in Traumatic Brain Injury.
Pre-clinical studies of traumatic brain injury (TBI) show that glyburide reduces edema and hemorrhagic progression of contusions. We conducted a small Phase II, three-institution, randomized placebo-controlled trial of subjects with TBI to assess the safety and efficacy of intravenous (IV) glyburide. Twenty-eight subjects were randomized and underwent a 72-h infusion of IV glyburide or placebo, beginning within 10 h of trauma. Of the 28 subjects, 25 had Glasgow Coma Scale (GCS) scores of 6-10, and 14 had contusions. There were no differences in adverse events (AEs) or severe adverse events (ASEs) between groups. The magnetic resonance imaging (MRI) percent change at 72-168 h from screening/baseline was compared between the glyburide and placebo groups. Analysis of contusions (7 per group) showed that lesion volumes (hemorrhage plus edema) increased 1036% with placebo versus 136% with glyburide (p = 0.15), and that hemorrhage volumes increased 11.6% with placebo but decreased 29.6% with glyburide (p = 0.62). Three diffusion MRI measures of edema were quantified: mean diffusivity (MD), free water (FW), and tissue MD (MDt), corresponding to overall, extracellular, and intracellular water, respectively. The percent change with time for each measure was compared in lesions (n = 14) versus uninjured white matter (n = 24) in subjects receiving placebo (n = 20) or glyburide (n = 18). For placebo, the percent change in lesions for all three measures was significantly different compared with uninjured white matter (analysis of variance [ANOVA], p < 0.02), consistent with worsening of edema in untreated contusions. In contrast, for glyburide, the percent change in lesions for all three measures was not significantly different compared with uninjured white matter. Further study of IV glyburide in contusion TBI is warranted
P300 asymmetry and positive symptom severity: A study in the early stage of a first episode of psychosis
Facilitating Pupil Thinking About Information Literacy
Whilst information literacy is frequently taught through the imposition on learners of an established framework, this paper suggests a different approach by taking a lead from James Herring’s ideas. Specifically, it provides guidance to school-based information professionals who would like to encourage their pupils to devise their own flexible, information literacy models which are unique to them. Drawing on existing material in information science and wider thought, it proposes areas for coverage and considers how information professionals may support the dynamic process of model construction. It is recommended that those who are intent on facilitating the creation of personal information literacy models help pupils to identify the roles they take on in their lives, to reflect on the information needs that result, to ascertain the information they require in particular situations, to explore their information-seeking activities, to consider means by which information can be captured and to give thought as to how the information they have accessed may be used. This framework is, however, by no means rigid and readers are, of course, free to make their own adjustments
- …