1,697 research outputs found

    Self-starting capability of a Darrieus turbine

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    Darrieus-type vertical axis wind turbines have a number of potential advantages for small-scale and domestic applications. For such applications, the issues of cost and reliability are paramount and hence simplicity of design of the structure, the generator, and any control system is vital. A particular concern relating to Darrieus turbines is their potential to self-start. If, as has been suggested by several authors, they require external assistance to start then much of their advantage is lost. The purpose of the study described here is, therefore, to investigate their starting performance through the development and validation of computational simulation and to determine the parameters that govern the capability to self-start. A case study is presented based upon the use of the widely used and well documented, symmetrical NACA 0012 turbine blade profile. It is shown that a lightly loaded, three-bladed rotor always has the potential to self start under steady wind conditions, whereas the starting of a two-bladed device is dependent upon its initial starting orientation

    Organic source of nitrogen trials & miscellaneous trials.

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    1. Nitrogen sources Badgingarra 85BA3 Organic Source of Nitrogen 8SBA4 Interaction of Organic and Inorganic Nitrogen sources 85BAS Miscellaneous Organic Nitrogen Sources 85BA39 Times and Levels of Inorganic Nitrogen Application Lancelin 85M02 Organic sources of nitrogen 85M03 Interaction of Organic and Inorganic Nitrogen Sources 85M04 Miscellaneous Organic Nitrogen Sources 85MOS3 Times and Levels of Inorganic Nitrogen Application Meckering 85N01 Organic Sources of Nitrogen 85N03 Miscellaneous Organic Nitrogen Sources 85NOS9 Times and Levels of Inorganic Nitrogen Application 2. Miscellaneous trials 84M6 Rates of Nitrogen on Wheat - CSIRO Megatrial (E. Harvey) 85M4 Nitrogen and Water on Wheat (with M. Mason) 83WH29 Residual Effects of Crop and Pasture Species on Second Wheat Crop 82WH2 Residual Value of Ripping (4th Year

    Modelling of the ICRF induced E x B convection in the scrape-off-layer of ASDEX Upgrade

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    In magnetic controlled fusion devices, plasma heating with radio-frequency (RF) waves in the ion cyclotron (IC) range of frequency relies on the electric field of the fast wave to heat the plasma. However, the slow wave can be generated parasitically. The electric field of the slow wave can induce large biased plasma potential (DC potential) through sheath rectification. The rapid variation of the rectified potential across the equilibrium magnetic field can cause significant convective transport (E x B drifts) in the scrape-off layer (SOL). In order to understand this phenomenon and reproduce the experiments, 3D realistic simulations are carried out with the 3D edge plasma fluid and kinetic neutral code EMC3-Eirene in ASDEX Upgrade. For this, we have added the prescribed drift terms to the EMC3 equations and verified the 3D code results against the analytical ones in cylindrical geometry. The edge plasma potential derived from the experiments is used to calculate the drift velocities, which are then treated as input fields in the code to obtain the final density distributions. Our simulation results are in good agreement with the experiments

    Practical Roadmap and Limits to Nanostructured Photovoltaics

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    The significant research interest in the engineering of photovoltaic (PV) structures at the nanoscale is directed toward enabling reductions in PV module fabrication and installation costs as well as improving cell power conversion efficiency (PCE). With the emergence of a multitude of nanostructured photovoltaic (nano-PV) device architectures, the question has arisen of where both the practical and the fundamental limits of performance reside in these new systems. Here, the former is addressed a posteriori. The specific challenges associated with improving the electrical power conversion efficiency of various nano-PV technologies are discussed and several approaches to reduce their thermal losses beyond the single bandgap limit are reviewed. Critical considerations related to the module lifetime and cost that are unique to nano-PV architectures are also addressed. The analysis suggests that a practical single-junction laboratory power conversion efficiency limit of 17% and a two-cell tandem power conversion efficiency limit of 24% are possible for nano-PVs, which, when combined with operating lifetimes of 10 to 15 years, could position them as a transformational technology for solar energy markets.Eni-MIT Alliance Solar Frontiers Program (Eni S.p.A. (Firm))National Science Foundation (U.S.). Graduate Research Fellowship ProgramLink FoundationHertz Foundation (Fellowship

    Analysis of English general practice level data linking medication levels, service activity and demography to levels of glycaemic control being achieved in type 2 diabetes to improve clinical practice and patient outcomes.

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    OBJECTIVE: Evaluate relative clinical effectiveness of treatment options for type 2 diabetes mellitus (T2DM) using a statistical model of real-world evidence within UK general practitioner practices (GPP), to quantify the opportunities for diabetes care performance improvement. METHOD: From the National Diabetes Audit in 2015-2016 and 2016-2017, GPP target glycaemic control (TGC-%HbA1c ≤58 mmol/mol) and higher glycaemic risk (HGR -%HbA1c results >86 mmol/mol) outcomes were linked using multivariate linear regression to prescribing, demographics and practice service indicators. This was carried out both cross-sectionally (XS) (within year) and longitudinally (Lo) (across years) on 35 indicators. Standardised β coefficients were used to show relative level of impact of each factor. Improvement opportunity was calculated as impact on TGC & HGR numbers. RESULTS: Values from 6525 GPP with 2.7 million T2DM individuals were included. The cross-sectional model accounted for up to 28% TGC variance and 35% HGR variance, and the longitudinal model accounted for up to 9% TGC and 17% HGR variance. Practice service indicators including % achieving routine checks/blood pressure/cholesterol control targets were positively correlated, while demographic indicators including % younger age/social deprivation/white ethnicity were negatively correlated. The β values for selected molecules are shown as (increased TGC; decreased HGR), canagliflozin (XS 0.07;0.145/Lo 0.04;0.07), metformin (XS 0.12;0.04/Lo -;-), sitagliptin (XS 0.06;0.02/Lo 0.10;0.06), empagliflozin (XS-;0.07/Lo 0.09;0.07), dapagliflozin (XS -;0.04/Lo -;0.4), sulphonylurea (XS -0.18;-0.12/Lo-;-) and insulin (XS-0.14;0.02/ Lo-0.09;-). Moving all GPP prescribing and interventions to the equivalent of the top performing decile of GPP could result in total patients in TGC increasing from 1.90 million to 2.14 million, and total HGR falling from 191 000 to 123 000. CONCLUSIONS: GPP using more legacy therapies such as sulphonylurea/insulin demonstrate poorer outcomes, while those applying holistic patient management/use of newer molecules demonstrate improved glycaemic outcomes. If all GPP moved service levels/prescribing to those of the top decile, both TGC/HGR could be substantially improved

    Polypharmacy, benzodiazepines, and antidepressants, but not antipsychotics, are associated with increased falls risk in UK care home residents: a prospective multi-centre study

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    Purpose: Falls and polypharmacy are both common in care home residents. Deprescribing of medications in residents with increased falls risk is encouraged. Psychotropic medications are known to increase falls risk in older adults. These drugs are often used in care home residents for depression, anxiety, and behavioural and psychological symptoms of dementia. However, few studies have explored the link between polypharmacy, psychotropic medications and falls risk in care home residents. Methods: A prospective cohort study of residents from 84 UK care homes. Data were collected from residents’ care records and medication administration records. Age, diagnoses, gender, number of medications and number of psychotropic medications were collected at baseline and residents were monitored over three months for occurrence of falls. Logistic regression models were used to assess the effect of multiple medications and psychotropic medication on falls whilst adjusting for confounders. Results: Of the 1,655 participants, mean age 85 (SD 8.9) years, 67.9% female, 519 (31%) fell in 3 months. Both the total number of regular drugs prescribed and taking ≥1 regular psychotropic medication were independent risk factors for falling (adjusted odds ratio (OR) 1.06 (95%CI 1.03-1.09,

    Encephalitis caused by a Lyssavirus in fruit bats in Australia.

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    This report describes the first pathologic and immunohistochemical recognition in Australia of a rabies-like disease in a native mammal, a fruit bat, the black flying fox (Pteropus alecto). A virus with close serologic and genetic relationships to members of the Lyssavirus genus of the family Rhabdoviridae was isolated in mice from the tissue homogenates of a sick juvenile animal
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