134 research outputs found

    INTEGRATED APPROACH TO THE SUPERPLASTIC FORMING OF MAGNESIUM ALLOYS

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    The economical and environmental issues associated with fossil fuels have been urging the automotive industry to cut the fuel consumption and exhaust emission levels, mainly by reducing the weight of vehicles. However, customers increasing demands for safer, more powerful and luxurious vehicles have been adding more weight to the various categories of vehicles, even the smallest ones. Leading car manufacturers have shown that significant weight reduction, yet satisfying the growing demands of customers, would not be feasible without the extensive use of lightweight materials. Magnesium is the lightest constructional metal on earth, offering a great potential for weight-savings. However, magnesium and its alloys exhibit inferior ductility at low temperatures, limiting their practical sheet metal applications. Interestingly, some magnesium alloys exhibit superplastic behaviour at elevated temperatures; mirrored by the extraordinarily large ductility, surpassing that of conventional steels and aluminium alloys. Superplastic forming technique is the process used to form materials of such nature, having the ability to deliver highly-profiled, yet very uniform sheet-metal products, in one single stage. Despite the several attractions, the technique is not widely-used because of a number of issues and obstacles. This study aims at advancing the superplastic forming technique, and offering it as an efficient process for broader utilisation of magnesium alloys for sheet metal applications. The focus is primarily directed to the AZ31 magnesium alloy, since it is commercially available in sheet form, possesses good mechanical properties and high strength/weight ratio. A general multi-axial anisotropic microstructure-based constitutive model that describes the deformation behaviour during superplastic forming is first developed. To calibrate the model for the AZ31 magnesium alloy, systematic uniaxial and biaxial stretching tests are carried out over wide-ranging conditions, using 3 specially-designed fixtures. In a collaborative effort thereafter, the calibrated constitutive model is fed into a FE code in conjunction with a stability criterion, in order to accurately simulate, control and ultimately optimise the superplastic forming process. Special pneumatic bulge forming setup is used to validate some proposed optimisation schemes, by forming sheets into dies of various geometries. Finally, the materials post-superplastic-forming properties are investigated systematically, based on geometrical, mechanical and microstructural measures

    Uniaxially-Driven Controlled Biaxial Testing Fixture

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    A uniaxially-driven controlled biaxial testing fixture includes a base, a first coupler mounted to the base, and a load input drive rack mounted for linear movement with respect to the base. A second coupler and a first specimen grip are both mounted to the load input drive rack. Second, third and fourth specimen grips are also mounted for linear movement with respect to the base. First, second and third drive mechanisms connect the load input drive rack to the second, third and fourth specimen grips. Together the four specimen grips are oriented to provide biaxial application of force to a test specimen

    Pharmaceutical Care in Children: Self-reported knowledge, attitudes and competency of final-year pharmacy students in Jordan

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    Objectives: Pharmacists require a baseline level of knowledge in paediatric pharmaceutical care in order to be able to adequately care for paediatric patients and counsel their families. This study aimed to explore the self-reported knowledge, attitudes and competency of final-year pharmacy students in Jordan regarding paediatric pharmaceutical care. Methods: This study took place in Jordan between November 2016 and May 2017. A 28-item questionnaire was designed and administered to 400 students from all pharmacy programmes in Jordan during their final year of training. Results: A total of 354 students agreed to take part in the study (response rate: 88.5%). Most respondents (95.2%) were aware of the term ‘paediatrics’. However, almost one-third of the respondents (30.5%) reported never having taken paediatric dose calculation courses and more than half (55.6%) were unfamiliar with the term ‘off-label medicines’. Moreover, most respondents (65.1%) had low knowledge scores (≤2 out of 5) when presented with realistic paediatric case scenarios. There were no significant differences in knowledge and attitudes between undergraduate and doctoral students or between those from public or private universities (P >0.05). Conclusion: The findings of this study highlight an alarming deficiency in paediatric pharmaceutical knowledge among final-year pharmacy students in Jordan. As such, paediatric-related content should be emphasised in the pharmacy curricula of Jordanian universities so that pharmacy students receive more formalised education and more extensive training in this area. Keywords: Pharmaceutical Care; Pediatrics; Pharmacy Students; Knowledge; Attitudes; Competency-Based Education; Jordan
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