4,578 research outputs found

    On the determination of flow stress using bulge test and mechanical measurement

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    The standard uniaxial tensile test is a widely accepted method to obtain relevant properties of sheet metal materials. These fundamental parameters can be used in numerical modeling of sheet forming operations to predict and assess formability and failure analysis. However the range of strain obtained from tensile test is limited and therefore if one will need further information on material behavior, extrapolation of tensile data is performed. The bulge test is an alternative to obtain ranges of deformation higher than tensile test, thus being possible to obtain non-extrapolated data for material behavior. Several methods may be used to obtain stress-strain data from bulge test, but a common concept is behind them, which needs the measurement of bulge pressure, curvature of bulge specimen, its thickness at the pole and the application of membrane theory. Concerning such measurements, optical methods are being used recently but classical mechanical methods are still an alternative with its own strengths. This paper presents the use and development of a mechanical measuring system to be incorporated in a hydraulic bulge test for flow curve determination, which permits real-time data acquisition under controlled strain rates up to high levels of plastic deformation. Numerical simulations of bulge test using FEM are performed and a sensitivity analysis is done for some influencing variables used in measurements, thus giving some directions in the design and use of the experimental mechanical system. Also, first experimental results are presented, showing an efficient testing procedure method for real time data acquisition with a stable evaluation of the flow curve.open11617Nsciescopu

    Overcoming the barriers to implementing urban road user charging schemes

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    Urban road user charging offers the potential to achieve significant improvements in urban transport, but is notoriously difficult to implement. Cities need guidance on the range of factors to be considered in planning and implementing such schemes. This paper summarises the results of a 3 year programme which has collated evidence on the issues of most concern to cities. A state of the art report has provided evidence on 14 themes, ranging from objectives and design to implementation and evaluation. A set of 16 case studies has reviewed experience in design and implementation across Europe. The paper summarises their findings, provides references to more detailed information, presents the resulting policy recommendations to European, national and local government, and outlines the areas in which further research is needed

    Systematic Review on the Associations between Objectively Measured Breaks in Sitting Time and Cardiovascular Health in Youth

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    The aim of this systematic review was to summarize the literature on the associations between breaks in sitting time and cardiovascular health, in children and adolescents. The search was conducted using five databases (MEDLINE, SCOPUS, WEB OF SCIENCE, PSYCINFO and CINAHL) through to 01 October 2019. Due to heterogeneity of the data, meta-analyses were not possible. We screened 2577 studies, and 15 studies were included, representing 9116 participants, from six different countries. Five observational studies and four experimental studies showed associations between breaks in sitting time and cardiovascular health, i.e. an increased number of breaks in sitting time was negatively associated with a cardiovascular health outcome. No associations between number of breaks in sitting time and cardiovascular health outcomes were found in the six remaining studies. Studies examining associations between breaks in sitting time and cardiovascular health in children have shown some favorable associations. More epidemiological evidence is required, to inform lifestyle interventions and public health policies, which could translate into long-term implications on population health

    Stem diameter and height of chrysanthemum cv Yoko ono as affected by gibberellic acid

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    The effect of gibberellic acid has been shown mainly to promote cell division and elongation. This study was aimed to evaluate the development of height and diameter of the stems of chrysanthemum cultivar Yoko ono by the applications of gibberellic acid (GA3) in the field. The treatments were composed of four doses (0, 40, 80 and 120 mg L-1) at 15 and 30 days after transplanting. From the findings, It can be concluded that GA3 significantly affected the diameter of stem at higher doses, and was unable to affect the height of stem.Key words: Dendranthema grandiflora, flowers, plant regulator, concentration

    Development and validation of a clinical prediction model for patient-reported pain and function after primary total knee replacement surgery

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    To develop and validate a clinical prediction model of patient-reported pain and function after undergoing total knee replacement (TKR). We used data of 1,649 patients from the Knee Arthroplasty Trial who received primary TKR across 34 centres in the UK. The external validation included 595 patients from Southampton University Hospital, and Nuffield Orthopaedic Centre (Oxford). The outcome was the Oxford Knee Score (OKS) 12-month after TKR. Pre-operative predictors including patient characteristics and clinical factors were considered. Bootstrap backward linear regression analysis was used. Low pre-operative OKS, living in poor areas, high body mass index, and patient-reported anxiety or depression were associated with worse outcome. The clinical factors associated with worse outcome were worse pre-operative physical status, presence of other conditions affecting mobility and previous knee arthroscopy. Presence of fixed flexion deformity and an absent or damaged pre-operative anterior cruciate ligament (compared with intact) were associated with better outcome. Discrimination and calibration statistics were satisfactory. External validation predicted 21.1% of the variance of outcome. This is the first clinical prediction model for predicting self-reported pain and function 12 months after TKR to be externally validated. It will help to inform to patients regarding expectations of the outcome after knee replacement surgery

    Sectoral specialisation in the EU a macroeconomic perspective

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    This paper analyses trends in sectoral specialisation in the EU and concludes the following: 1) The European production structure appears more homogenous than that of the US. 2) While sectoral specialisation has shown a slight increase in some smaller euro area countries towards the end-1990s, it is too early to detect any potential impact of EMU. 3) Despite some changes in sectoral composition, the business cycles of euro area countries became more synchronised over the 1990s, which may be seen as reassuring from the point of view of the single monetary policy. 4) Sectoral re-allocation accounts for as much as 50% of the increase in labour productivity growth in business sector services in the euro area. 5) The slowdown of European labour productivity growth relative to the US since the mid-1990s is explained by a stronger performance in the US wholesale and retail trade, financial intermediation and high-tech manufacturing sectors.

    The course of specialization in public health in Rio de Janeiro, Brazil, from 1926 to 2006: lessons and challenges

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    <p>Abstract</p> <p>Background</p> <p>Public health, as a field of knowledge, depends on its professionals. Their education and training, therefore, is considered to be an important factor for the quality of health services. In Brazil, the Course of Specialization in Public Health of the National School of Public Health is one of the oldest in the country. The course has existed for over 80 years, during which it has had an eventful history, with modifications in its organization, interruptions in its delivery, threats to its survival and changes in the institutions hosting it, reflecting the wider transformation in Brazilian society and public life over that period.</p> <p>Methods</p> <p>In this article we analyse this course via its history, disciplines, organization and characteristics of the student body.</p> <p>Results</p> <p>Insights were gained into the advancement of public health in Brazil and the progress of education for professionals in this field was highlighted. The course has formed nearly 2000 specialists in public health.</p> <p>Conclusions</p> <p>An analysis of the course's history provides valuable lessons for other schools of public health trying to train professionals in developing countries.</p
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