1,032 research outputs found

    The risk of buildings overheating in a low-carbon climate change future

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    An overheating risk tool that is compatible with building performance simulation software has been developed, using principal component analysis to give a statistically rigorous simplification of the UKCP09 probabilistic climate projections. The tool converts a single dynamic simulation output into many hundreds of simulation results at hourly resolution for equally-probable climates from the UKCP09 weather generator. The result is a population of outcomes for the performance of a specific building in a future climate, thus helping the user choose adaptation technologies that might reduce the risk of overheating. The outputs of the LCF tool can be delivered as a risk matrix or a probabilistic overheating curve. The perceptions and requirements of potential users were assessed and, for non-domestic buildings in particular, the need to quantify and assess overheating risk was understood by professionals, with concerns expressed for the ease of incorporation of the UKCP09 projections into this process. The new tool has the potential to meet these concerns

    Pionic charge exchange on the proton from 40 to 250 MeV

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    The total cross sections for pionic charge exchange on hydrogen were measured using a transmission technique on thin CH2 and C targets. Data were taken for pi- lab energies from 39 to 247 MeV with total errors of typically 2% over the Delta-resonance and up to 10% at the lowest energies. Deviations from the predictions of the SAID phase shift analysis in the 60 to 80 MeV region are interpreted as evidence for isospin-symmetry breaking in the s-wave amplitudes. The charge dependence of the Delta-resonance properties appears to be smaller than previously reported

    Validation of the DECAF score to predict hospital mortality in acute exacerbations of COPD

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    Background Hospitalisation due to acute exacerbations of COPD (AECOPD) is common, and subsequent mortality high. The DECAF score was derived for accurate prediction of mortality and risk strati fi cation to inform patient care. We aimed to validate the DECAF score, internally and externally, and to compare its performance to other predictive tools. Methods The study took place in the two hospitals within the derivation study (internal validation) and in four additional hospitals (external validation) between January 2012 and May 2014. Consecutive admissions were identi fi ed by screening admissions and searching coding records. Admission clinical data, including DECAF indices, and mortality were recorded. The prognostic value of DECAF and other scores were assessed by the area under the receiver operator characteristic (AUROC) curve. Results In the internal and external validation cohorts, 880 and 845 patients were recruited. Mean age was 73.1 (SD 10.3) years, 54.3% were female, and mean (SD) FEV 1 45.5 (18.3) per cent predicted. Overall mortality was 7.7%. The DECAF AUROC curve for inhospital mortality was 0.83 (95% CI 0.78 to 0.87) in the internal cohort and 0.82 (95% CI 0.77 to 0.87) in the external cohort, and was superior to other prognostic scores for inhospital or 30-day mortality. Conclusions DECAF is a robust predictor of mortality, using indices routinely available on admission. Its generalisability is supported by consistent strong performance; it can identify low-risk patients (DECAF 0 – 1) potentially suitable for Hospital at Home or early supported discharge services, and high-risk patients (DECAF 3 – 6) for escalation planning or appropriate early palliation. Trial registration number UKCRN ID 14214

    The effect of near-surface plastic deformation on the hot corrosion and high temperature corrosion-fatigue response of a nickel-based superalloy

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    Surface treatments such as shot peening to inhibit fatigue crack initiation are essential processes when designing gas turbine components for aerospace applications. It is therefore crucial to understand the effects of shot peening in representative service environments. Here, the influence of surface treatment on the high temperature corrosion fatigue response of a polycrystalline nickel-based superalloy is considered, an area that has not previously been explored. Two shot peening conditions; 110H 7A 200% and 330H 7A 200%, along with a polished surface were chosen. Specimens were salted and exposed to SO2 gas during fatigue testing at 700 °C. A range of novel techniques including SEM, EBSD and axial chromatism profilometry were used to analyse the near surface cold work and surface condition before and after testing. EBSD local misorientation maps, paired with an increase in corrosion-fatigue life, suggest that a greater depth of cold work produced by the smaller shot size (110H), is providing a significant benefit in terms of hot corrosion and corrosion-fatigue performance. This paper concludes that the presence of a substantial layer of cold work is required to account for any metal loss due to the effects of hot corrosion. It is also evident that cold work hinders fatigue crack initiation and delays the onset of pit to crack transition

    CHIMPS: the 13CO/C18O (J = 3 to 2) Heterodyne Inner Milky Way Plane Survey

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    We present the 13CO/C18O (J = 3 → 2) Heterodyne Inner Milky Way Plane Survey (CHIMPS) which has been carried out using the Heterodyne Array Receiver Program on the 15 m James Clerk Maxwell Telescope (JCMT) in Hawaii. The high-resolution spectral survey currently covers |b| ≤ 0.5° and 28° ≲ l ≲ 46°, with an angular resolution of 15 arcsec in 0.5 km s-1 velocity channels. The spectra have a median rms of ˜0.6 K at this resolution, and for optically thin gas at an excitation temperature of 10 K, this sensitivity corresponds to column densities of NH2 ˜ 3 × 1020 cm-2 and NH2 ˜ 4 × 1021 cm-2 for 13CO and C18O, respectively. The molecular gas that CHIMPS traces is at higher column densities and is also more optically thin than in other publicly available CO surveys due to its rarer isotopologues, and thus more representative of the three-dimensional structure of the clouds. The critical density of the J = 3 → 2 transition of CO is ≳104 cm-3 at temperatures of ≤20 K, and so the higher density gas associated with star formation is well traced. These data complement other existing Galactic plane surveys, especially the JCMT Galactic Plane Survey which has similar spatial resolution and column density sensitivity, and the Herschel infrared Galactic Plane Survey. In this paper, we discuss the observations, data reduction and characteristics of the survey, presenting integrated-emission maps for the region covered. Position-velocity diagrams allow comparison with Galactic structure models of the Milky Way, and while we find good agreement with a particular four-arm model, there are some significant deviations.Peer reviewedFinal Accepted Versio

    Homologous Flares and Magnetic Field Topology in Active Region NOAA 10501 on 20 November 2003

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    We present and interpret observations of two morphologically homologous flares that occurred in active region (AR) NOAA 10501 on 20 November 2003. Both flares displayed four homologous H-alpha ribbons and were both accompanied by coronal mass ejections (CMEs). The central flare ribbons were located at the site of an emerging bipole in the center of the active region. The negative polarity of this bipole fragmented in two main pieces, one rotating around the positive polarity by ~ 110 deg within 32 hours. We model the coronal magnetic field and compute its topology, using as boundary condition the magnetogram closest in time to each flare. In particular, we calculate the location of quasiseparatrix layers (QSLs) in order to understand the connectivity between the flare ribbons. Though several polarities were present in AR 10501, the global magnetic field topology corresponds to a quadrupolar magnetic field distribution without magnetic null points. For both flares, the photospheric traces of QSLs are similar and match well the locations of the four H-alpha ribbons. This globally unchanged topology and the continuous shearing by the rotating bipole are two key factors responsible for the flare homology. However, our analyses also indicate that different magnetic connectivity domains of the quadrupolar configuration become unstable during each flare, so that magnetic reconnection proceeds differently in both events.Comment: 24 pages, 10 figures, Solar Physics (accepted

    Charged pion form factor between Q^2=0.60 and 2.45 GeV^2. II. Determination of, and results for, the pion form factor

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    The charged pion form factor, Fpi(Q^2), is an important quantity which can be used to advance our knowledge of hadronic structure. However, the extraction of Fpi from data requires a model of the 1H(e,e'pi+)n reaction, and thus is inherently model dependent. Therefore, a detailed description of the extraction of the charged pion form factor from electroproduction data obtained recently at Jefferson Lab is presented, with particular focus given to the dominant uncertainties in this procedure. Results for Fpi are presented for Q^2=0.60-2.45 GeV^2. Above Q^2=1.5 GeV^2, the Fpi values are systematically below the monopole parameterization that describes the low Q^2 data used to determine the pion charge radius. The pion form factor can be calculated in a wide variety of theoretical approaches, and the experimental results are compared to a number of calculations. This comparison is helpful in understanding the role of soft versus hard contributions to hadronic structure in the intermediate Q^2 regime.Comment: 18 pages, 11 figure
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