117 research outputs found

    Simulation and implementation of heat load shifting in a low carbon building

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    A predictive load shifting control system for a heat pump has been developed and installed in a low carbon test house located at the BRE Innovation Park, Motherwell, near Glasgow. The house features an exhaust-air source heat pump supplying an under floor heating system. The controller predicted the day-ahead space heating requirements for the house, based on forecast air temperatures and solar radiation levels and then automatically set the heat pump’s start and stop times for the following day. The heat pump’s operation was restricted where possible to off-peak electricity tariff periods (00:00-07:00). The controller’s operating parameters were pre-set using a calibrated building simulation model. After installation, the controller’s performance was monitored during September 2015 and analysis of test data showed that the predictive control maintained indoor air temperatures between 18-23oC for around 87% of notional occupied hours between 07:00-22:00; this was better than predicted by simulation. However, the energy performance of the heat pump was extremely poor as it did not function well under intermittent load-shifting operation, with the majority of the heat was delivered primarily by an auxiliary immersion coil rather than the heat pump itself. The paper concludes with suggestions for refinements to the controller and further work

    Simulation, implementation and monitoring of heat pump load shifting using a predictive controller

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    A predictive load shifting controller has been developed and deployed in a low-carbon house near Glasgow, UK. The house features an under floor heating system, fed by an air-source heat pump. Based on forecast air temperatures and solar radiation levels, the controller 1) predicts the following day’s heating requirements to achieve thermal comfort 2) runs heat pump during off peak periods to deliver the required heat by pre-charging the under floor heating. Prior to its installation in the building, the controller’s operating characteristics were identified using a calibrated building simulation model. The performance of the controller in the house was monitored over four weeks in 2015. The monitored data indicated that the actual thermal performance of the predictive controller was better than that projected using simulation, with better levels of thermal comfort achieved. Indoor air temperatures were between 18°C to 23°C for around 87% of the time between 07:00-22:00. However, the performance of the heat pump under load shift control was extremely poor, with the heat being delivered primarily by the unit’s auxiliary immersion coil. The paper concludes with a refined version of the controller that should improve the day-ahead energy predictions and offer greater flexibility in heat pump operation for future field trials

    UV-optical from space

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    The following subject areas are covered: (1) the science program (star formation and origins of planetary systems; structure and evolution of the interstellar medium; stellar population; the galactic and extragalactic distance scale; nature of galaxy nuclei, AGNs, and QSOs; formation and evolution of galaxies at high redshifts; and cosmology); (2) implementation of the science program; (3) the observatory-class missions (HST; LST - the 6m successor to HST; and next-generation 16m telescope); (4) moderate and small missions (Delta-class Explorers; imaging astrometric interferometer; small Explorers; optics development and demonstrations; and supporting ground-based capabilities); (5) prerequisites - the current science program (Lyman-FUSE; HTS optimization; the near-term science program; data analysis, modeling, and theory funding; and archives); (6) technologies for the next century; and (7) lunar-based telescopes and instruments

    Developing the accredited postgraduate assessment program for Fellowship of the Australian College of Rural and Remote Medicine

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    Introduction: Accreditation of the Australian College of Rural and Remote Medicine (ACRRM) as a standards and training provider, by the Australian Medical Council (AMC) in 2007, is the first time in the world that a peak professional organisation for rural and remote medical education has been formally recognised. As a consequence, the Australian Government provided rural and remote medicine with formal recognition under Medicare as a generalist discipline. This accreditation was based on the ability of ACRRM to meet the AMC's guidelines for its training and assessment program.\ud \ud Methods: The methodology was a six-step process that included: developing an assessment blueprint and a classification scheme; identifying an assessment model; choosing innovative summative and formative assessment methods that met the needs of rural and remote located medical practitioner candidates; 21 rural doctors and academics developing the assessment items as part of a week-long writing workshop; investigating the feasibility of purchasing assessment items; and 48 rural candidates piloting three of the assessment items to ensure they would meet the guidelines for national accreditation.\ud \ud Results: The project resulted in an innovative formative and summative assessment program that occurs throughout 4 years of vocational training, using innovative, reliable, valid and acceptable methods with educational impact. The piloting process occurred for 3 of the 6 assessment tools. Structured Assessment Using Multiple Patient Scenarios (StAMPS) is a new assessment method developed as part of this project. The StAMPS pilot found that it was reliable, with a generalisability coefficient of >0.76 and was a valid, acceptable and feasible assessment tool with desired educational impact. The multiple choice question (MCQ) examination pilot found that the applied clinical nature of the questions and their wide range of scenarios proved a very acceptable examination to the profession. The web based in-training assessment examination pilot revealed that it would serve well as a formative process until ACRRM can further develop their MCQ database.\ud \ud Conclusions: The ACRRM assessment program breaks new ground for assessing rural and remote doctors in Australia, and provides new evidence regarding how a comprehensive and contemporary assessment system can work within a postgraduate medical setting

    Photon Trapping Enables Super-Eddington Growth of Black-Hole Seeds in Galaxies at High Redshift

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    We identify a physical mechanism that would have resulted in rapid, obscured growth of seed super-massive black-holes in galaxies at z>6. Specifically, we find that the density at the centre of typical high redshift galaxies was at a level where the Bondi accretion rate implies a diffusion speed of photons that was slower than the gravitational infall velocity, resulting in photons being trapped within the accretion flow and advected into the black-hole. We show that there is a range of black-hole masses (M_bh ~ 10^3-10^5 solar masses) where the accretion flow traps radiation, corresponding to black-holes that were massive enough to generate a photon trapping accretion flow, but small enough that their Bondi radii did not exceed the isothermal scale height of self-gravitating gas. Under these conditions we find that the accretion reaches levels far in excess of the Eddington rate. A prediction of this scenario is that X-ray number counts of active galactic nuclei at z>6 would exhibit a cutoff at the low luminosities corresponding to black-hole masses below ~10^5 solar masses. At low redshifts we find photon trapping to be unimportant because it could only occur in rare low spin halos, and would require black-hole masses in excess of expectations from the observed black-hole - halo mass relation. The super-Eddington growth of ~10^5 solar mass seed black-holes at high redshift may have provided a natural acceleration towards the growth of super-massive black-holes at z~6-7, less than a billion years after the Big Bang.Comment: 10 pages, 4 figures. Submitted to MNRA

    Spatio-temporal trends in normal-fault segmentation recorded by low-temperature thermochronology: Livingstone fault scarp, Malawi Rift, East African Rift System

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    The evolution of through-going normal-fault arrays from initial nucleation to growth and subsequent interaction and mechanical linkage is well documented in many extensional provinces. Over time, these processes lead to predictable spatial and temporal variations in the amount and rate of displacement accumulated along strike of individual fault segments, which should be manifested in the patterns of footwall exhumation. Here, we investigate the along-strike and vertical distribution of low-temperature apatite (U–Th)/He (AHe) cooling ages along the bounding fault system, the Livingstone fault, of the Karonga Basin of the northern Malawi Rift. The fault evolution and linkage from rift initiation to the present day has been previously constrained through investigations of the hanging wall basin fill. The new cooling ages from the footwall of the Livingstone fault can be related to the adjacent depocentre evolution and across a relay zone between two palaeo-fault segments. Our data are complimented by published apatite fission-track (AFT) data and reveal significant variation in rock cooling history along-strike: the centre of the footwall yields younger cooling ages than the former tips of earlier fault segments that are now linked. This suggests that low-temperature thermochronology can detect fault interactions along strike. That these former segment boundaries are preserved within exhumed footwall rocks is a function of the relatively recent linkage of the system. Our study highlights that changes in AHe (and potentially AFT) ages associated with the along-strike displacement profile can occur over relatively short horizontal distances (of a few kilometres). This is fundamentally important in the assessment of the vertical cooling history of footwalls in extensional systems: temporal differences in the rate of tectonically driven exhumation at a given location along fault strike may be of greater importance in controlling changes in rates of vertical exhumation than commonly invoked climatic fluctuations

    Outcomes of Cardiac Screening in Adolescent Soccer Players.

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    BACKGROUND: Reports on the incidence and causes of sudden cardiac death among young athletes have relied largely on estimated rates of participation and varied methods of reporting. We sought to investigate the incidence and causes of sudden cardiac death among adolescent soccer players in the United Kingdom. METHODS: From 1996 through 2016, we screened 11,168 adolescent athletes with a mean (±SD) age of 16.4±1.2 years (95% of whom were male) in the English Football Association (FA) cardiac screening program, which consisted of a health questionnaire, physical examination, electrocardiography, and echocardiography. The FA registry was interrogated to identify sudden cardiac deaths, which were confirmed with autopsy reports. RESULTS: During screening, 42 athletes (0.38%) were found to have cardiac disorders that are associated with sudden cardiac death. A further 225 athletes (2%) with congenital or valvular abnormalities were identified. After screening, there were 23 deaths from any cause, of which 8 (35%) were sudden deaths attributed to cardiac disease. Cardiomyopathy accounted for 7 of 8 sudden cardiac deaths (88%). Six athletes (75%) with sudden cardiac death had had normal cardiac screening results. The mean time between screening and sudden cardiac death was 6.8 years. On the basis of a total of 118,351 person-years, the incidence of sudden cardiac death among previously screened adolescent soccer players was 1 per 14,794 person-years (6.8 per 100,000 athletes). CONCLUSIONS: Diseases that are associated with sudden cardiac death were identified in 0.38% of adolescent soccer players in a cohort that underwent cardiovascular screening. The incidence of sudden cardiac death was 1 per 14,794 person-years, or 6.8 per 100,000 athletes; most of these deaths were due to cardiomyopathies that had not been detected on screening. (Funded by the English Football Association and others.)

    Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

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    Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy
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