477 research outputs found

    Using CFD to improve the design of a circulating water channel

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    Computational Fluid Dynamics (CFD) has been used as a design tool to investigate means of improving flow uniformity in the working section of a circulating water channel. The CFD model was based on a 1/10th scale wind-tunnel model of the circulating water channel at the Australian Maritime Hydrodynamics Research Centre (AMHRC). The CFD analysis was compared with experimental results obtained from the wind-tunnel model to validate the use of the CFD model. Three changes to the design were investigated; alteration of turning vane angle, increased resistance coefficient of a honeycomb screen and addition of trailing edge extensions to the turning vanes. The turning vane angle changes resulted in little improvement in flow uniformity. Increasing the resistance coefficient of the honeycomb screen resulted in improved uniformity, but at the expense of increased pressure loss. The addition of trailing edge extensions to the turning vanes resulted in the most significant improvements in flow uniformity. These results will be useful in selecting improvements to the circulating water channel

    Domestic heating behaviour and room temperatures: Empirical evidence from Scottish homes

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    In this paper, we describe patterns of residential heating based on data from 255 homes in and around Edinburgh, Scotland, UK, spanning August 2016 to June 2018. We describe: (i) the room temperatures achieved, (ii) the diurnal durations of heating use, and (iii) common diurnal patterns of heating behaviour. We investigate how these factors vary between weekdays and weekends, over the course of the year, by external temperature, and by room type. We compare these empirical findings with the simplifying assumptions about heating patterns found in the UK’s Standard Assessment Procedure (SAP), a widely-used building energy performance model. There are areas of concurrence and others of substantial difference with these model assumptions. Indoor achieved temperatures are substantially lower than SAP assumptions. The duration and timings of heating use vary substantially between homes and along lines of season and outdoor temperature, whereas the SAP model assumes no such variation. Little variation is found along the lines of weekday vs. weekend, whereas the SAP model assumes differences, or between living space and other rooms, consistent with the SAP. The results are relevant for those interested in how SAP assumptions regarding household heating behaviours and achieved indoor temperatures concur with empirical data

    Natural and Induced Mitochondrial Phosphate Carrier Loss: DIFFERENTIAL DEPENDENCE OF MITOCHONDRIAL METABOLISM AND DYNAMICS AND CELL SURVIVAL ON THE EXTENT OF DEPLETION.

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    The relevance of mitochondrial phosphate carrier (PiC), encoded by SLC25A3, in bioenergetics is well accepted. However, little is known about the mechanisms mediating the cellular impairments induced by pathological SLC25A3 variants. To this end, we investigated the pathogenicity of a novel compound heterozygous mutation in SLC25A3 First, each variant was modeled in yeast, revealing that substituting GSSAS for QIP within the fifth matrix loop is incompatible with survival on non-fermentable substrate, whereas the L200W variant is functionally neutral. Next, using skin fibroblasts from an individual expressing these variants and HeLa cells with varying degrees of PiC depletion, PiC loss of ∼60% was still compatible with uncompromised maximal oxidative phosphorylation (oxphos), whereas lower maximal oxphos was evident at ∼85% PiC depletion. Furthermore, intact mutant fibroblasts displayed suppressed mitochondrial bioenergetics consistent with a lower substrate availability rather than phosphate limitation. This was accompanied by slowed proliferation in glucose-replete medium; however, proliferation ceased when only mitochondrial substrate was provided. Both mutant fibroblasts and HeLa cells with 60% PiC loss showed a less interconnected mitochondrial network and a mitochondrial fusion defect that is not explained by altered abundance of OPA1 or MFN1/2 or relative amount of different OPA1 forms. Altogether these results indicate that PiC depletion may need to be profound (\u3e85%) to substantially affect maximal oxphos and that pathogenesis associated with PiC depletion or loss of function may be independent of phosphate limitation when ATP requirements are not high

    The SERL Observatory Dataset: Longitudinal Smart Meter Electricity and Gas Data, Survey, EPC and Climate Data for over 13,000 Households in Great Britain

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    The Smart Energy Research Lab (SERL) Observatory dataset described here comprises half-hourly and daily electricity and gas data, SERL survey data, Energy Performance Certificate (EPC) input data and 24 local hourly climate reanalysis variables from the European Centre for Medium-Range Weather Forecasts (ECMWF) for over 13,000 households in Great Britain (GB). Participants were recruited in September 2019, September 2020 and January 2021 and their smart meter data are collected from up to one year prior to sign up. Data collection will continue until at least August 2022, and longer if funding allows. Survey data relating to the dwelling, appliances, household demographics and attitudes were collected at sign up. Data are linked at the household level and UK-based academic researchers can apply for access within a secure virtual environment for research projects in the public interest. This is a data descriptor paper describing how the data were collected, the variables available and the representativeness of the sample compared to national estimates. It is intended to be a guide for researchers working with or considering using the SERL Observatory dataset, or simply looking to learn more about it

    The over-prediction of energy use by EPCs in Great Britain: A comparison of EPC-modelled and metered primary energy use intensity

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    This analysis compares the difference between the Energy Performance Certificate (EPC)-modelled and smart-meter measured annual energy use on a like-for-like basis in 1,374 gas-heated British households from the Smart Energy Research Lab (SERL) Observatory. EPCs and metered energy use were converted to primary energy use intensity (PEUI) to provide a comparison of the same quantity for the first time. We show that EPCs predict significantly more energy use than metered in homes in Great Britain. EPC bands A and B show no statistically significant difference, but all other bands show a significant gap which increases as EPC rating worsens. The PEUI gap widens from −26 kWh/yr/m2 (−8%) for band C to −276 kWh/y/m2 (−48%) for bands F and G. Unlike previous research, we show that the difference persists in homes matching the EPC-model assumptions regarding occupancy, thermostat set-point and whole-home heating; suggesting that occupant behaviour is unlikely to fully explain the discrepancy. EPCs are a core tool in the residential energy sector, and the gap between EPC-modelled and metered energy use could have a significant impact on policy, research, and industry. Future research should investigate disaggregated components of energy use, the underlying thermal model, and assumptions regarding building characteristics

    New Young Star Candidates in BRC 27 and BRC 34

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    We used archival Spitzer Space Telescope mid-infrared data to search for young stellar objects (YSOs) in the immediate vicinity of two bright-rimmed clouds, BRC 27 (part of CMa R1) and BRC 34 (part of the IC 1396 complex). These regions both appear to be actively forming young stars, perhaps triggered by the proximate OB stars. In BRC 27, we find clear infrared excesses around 22 of the 26 YSOs or YSO candidates identified in the literature, and identify 16 new YSO candidates that appear to have IR excesses. In BRC 34, the one literature-identified YSO has an IR excess, and we suggest 13 new YSO candidates in this region, including a new Class I object. Considering the entire ensemble, both BRCs are likely of comparable ages, within the uncertainties of small number statistics and without spectroscopy to confirm or refute the YSO candidates. Similarly, no clear conclusions can yet be drawn about any possible age gradients that may be present across the BRCs.Comment: 54 pages, 19 figures, accepted by A
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