58 research outputs found

    Uniaxial compression of single crystal and polycrystalline tantalum

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    A series of compression experiments characterising the elastic-plastic response of single crystal and polycrystalline tantalum from quasi-static to intermediate strain-rates (10^−3 – 10^3 s−1) over a range of temperatures (233–438 K) are reported in this paper. The single crystal experiments show significant differences in the response of the three principle crystal orientations of tantalum in terms of yield, work hardening and ultimate deformed shapes. Modelling is undertaken using a dislocation mechanics based crystal plasticity finite element model giving insight into the underlying microscopic processes that govern the macroscopic response. The simulations show the importance of the dislocation mobility relations and laws governing the evolution of the mobile dislocation density for capturing the correct behaviours. The inclusion of the twinning/anti-twinning asymmetry is found to influence [100] orientation most strongly, and is shown to be critical for matching the relative yield strengths. In general the simulations are able to adequately match experimental trends although some specific details such as exact strain hardening evolution are not reproduced suggesting a more complex hardening model is required. 3D finite element simulations approximating the tests are also undertaken and are able to predict the final deformed sample shapes well once the twinning/anti-twinning asymmetry is included (particularly for the [100] orientation). The polycrystalline data in both as-received and cold rolled conditions shows the initial yield strength is highest and work hardening rate is lowest for the cold-rolled material due to the increase in mobile dislocation density caused by the prior work. The general behavioural trends with temperature and strain-rate of the polycrystalline materials are reproduced in the single crystal data however the specific form of stress versus strain curves are significantly different. This is discussed in terms of the similar active slip systems in polycrystalline material to high symmetry single crystals but with the significant added effect of grain boundary interactions

    Dimethyl fumarate in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial

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    Dimethyl fumarate (DMF) inhibits inflammasome-mediated inflammation and has been proposed as a treatment for patients hospitalised with COVID-19. This randomised, controlled, open-label platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing multiple treatments in patients hospitalised for COVID-19 (NCT04381936, ISRCTN50189673). In this assessment of DMF performed at 27 UK hospitals, adults were randomly allocated (1:1) to either usual standard of care alone or usual standard of care plus DMF. The primary outcome was clinical status on day 5 measured on a seven-point ordinal scale. Secondary outcomes were time to sustained improvement in clinical status, time to discharge, day 5 peripheral blood oxygenation, day 5 C-reactive protein, and improvement in day 10 clinical status. Between 2 March 2021 and 18 November 2021, 713 patients were enroled in the DMF evaluation, of whom 356 were randomly allocated to receive usual care plus DMF, and 357 to usual care alone. 95% of patients received corticosteroids as part of routine care. There was no evidence of a beneficial effect of DMF on clinical status at day 5 (common odds ratio of unfavourable outcome 1.12; 95% CI 0.86-1.47; p = 0.40). There was no significant effect of DMF on any secondary outcome

    Wind energy assessment under strong mesoscale forcing

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    A comparison between a numerical mesoscale model and the computationally simpler flow model developed as part of the European wind atlas is presented. Despite observed horizontal variations in topographically induced mesoscale forcing which is not incorporated in the simpler model, there is general agreement on an order of magnitude assessment of the wind energy variations. The range of applicability of such simpler wind energy assessment models is shown to be limited to regions where the mesoscale forcing inherent in the base observations has not varied appreciably

    Second opinions in oncology: the experiences of patients attending the Sydney Cancer Centre.

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    Objective: To investigate the frequency, goals and outcomes of second-opinion consultations at the Sydney Cancer Centre. Design, setting and participants: A questionnaire-based study of patients who registered to see a medical oncologist at the Sydney Cancer Centre between January 2006 and January 2008 and who were seeking a second opinion. Main outcome measures: Proportion and demographic characteristics of patients who had previously seen a medical oncologist and who stated they were seeking a second opinion. Results: 123 of 1892 new patients (6.5%) stated that they were seeking a second opinion, of whom 22 declined study participation, were excluded from study participation or had been referred specifically for enrolment in a particular clinical trial. Of the remaining 101 patients, 77 completed a questionnaire; 59 were women and 26 had a university degree. Reasons for seeking second opinions included: to obtain information related to treatment (54 patients), for reassurance about diagnosis or treatment (47), and dissatisfaction with the information given by the first medical oncologist (24). Sixty-four patients reported that they received new information at the second-opinion consultation, with 45 identifying discussion of treatment options and 34 identifying discussion of future or prognosis. Fifty-one patients reported how the second-opinion consultation differed from the first, identifying it as longer (24), and indicating that the oncologist answered concerns (26). Most patients were aware of multidisciplinary teams and treatment guidelines, but fewer had read guidelines. Conclusions: Patients seeking a second opinion from a medical oncologist are typically more educated, younger and female, probably due to preferences for more detailed information. The most common reasons for seeking a second opinion were to obtain additional information or reassurance about recommended management. (aut. ref.

    Izmir subterranean clover (Trifolium subterraneum L. var. subterraneum)

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    Izmir is a hardseeded, early flowering, subterranean clover of var. subterraneum (Katz. et Morley) Zohary and Heller collected from Turkey and developed by the collaborating organisations of the National Annual Pasture Legume Improvement Program. It is a more hardseeded replacement for Nungarin and best suited to well-drained, moderately acidic soils in areas with a growing season of less than 4.5 months. Izmir seed production and regeneration densities in 3-year pasture phases were similar to Nungarin in 21 trials across southern Australia, but markedly greater in years following a crop or no seed set. Over all measurements, Izmir produced 10% more winter herbage and 7% more spring herbage than Nungarin. Its greater hardseededness and good seed production, makes it better suited to cropping rotations than Nungarin. Softening of Izmir hard seeds occurs later in the summer–autumn period than Nungarin, giving it slightly greater protection from seed losses following false breaks to the season. Izmir is recommended for sowing in Western Australia, New South Wales, Victoria, South Australia and Queensland. Izmir has been granted Plant Breeders Rights in Australia
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