24 research outputs found

    Reporting of health estimates prior to GATHER: a scoping review

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    Background: Generating estimates of health indicators at the global, regional, and country levels is increasingly in demand in order to meet reporting requirements for global and country targets, such as the sustainable development goals (SDGs). However, such estimates are sensitive to availability of input data, underlying analytic assumptions, variability in statistical techniques, and often have important limitations. From a user perspective, there is often a lack of transparency and replicability. In order to define best practices in reporting data and methods used to calculate health estimates, the Guidelines for Accurate and Transparent Health Estimates Reporting (GATHER) working group developed a minimum checklist of 18 items that must be reported within each study publishing health estimates, so that users may make an assessment of the quality of the estimate. Objective: We conducted a scoping review to assess the state of reporting amongst a cross-sectional sample of studies published prior to the publication of GATHER. Methods: We generated a sample of UN reports and journal articles through a combination of a Medline search and hand-searching published health estimates. From these studies we extracted the percentage of studies correctly reporting each item on the checklist, the proportion of items reported per study (the GATHER performance score), and how this score varied depending on study type. Results: The average proportion of items reported per study was 0.47, and the poorest-performing items related to documentation and availability of input data, availability of the statistical code used and the subsequent output data, and a complete detailed description of all the steps of the data analysis. Conclusions: Methods for health estimates are not currently fully reported, and the implementation of the GATHER guidelines will improve the availability of information required to make an assessment of study quality

    Track D Social Science, Human Rights and Political Science

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138414/1/jia218442.pd

    Knowing the limits of a trend : examining the onset of asymptotic stable fracture behaviour in mode II fatigue delamination growth

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    This study is motivated by the possibility that experimental data sets, particularly those obtained at high R-ratios, may unknowingly contain data points within the asymptotic stable fracture region that influence its perceived log-linear behaviour and the fit of various loglinear delamination growth models. Results from the experimental investigation indicate that the asymptotic stable fracture region can extend to GIImax values as low as 0.7GIIc.Peer reviewed: YesNRC publication: Ye

    Beyond the orthogonal: On the influence of build orientation on fatigue crack growth in SLM Ti-6Al-4V

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    A challenge in developing an in-depth understanding of the crack growth resistance of Additively Manufactured materials is the fact that their mechanical properties have been shown to be both process and part-geometry dependent. Up to now, no studies have investigated the influence of off-axis (beyond the three orthogonal build orientations) orientations on the fatigue crack growth behaviour of selective laser melted Ti-6Al-4V. Furthermore, the widespread use of compact tension specimens for investigating the material behaviour generates data more suitable for plane-strain conditions, rather than the plane-stress state which is more applicable to many lightweight aerospace structures. To address this gap in knowledge, a comprehensive study was carried out to investigate the influence of off-axis build direction in thin SLM Ti-6Al-4V plates, with a focus on the influence of columnar grain orientation on the fatigue crack growth behaviour. It was found that although a macroscopic columnar grain structure is visible on the specimens, it had no discernible influence on the crack growth resistance when the specimen had undergone a stress relieving or HIP heat treatment.Structural Integrity & CompositesEducation A

    Teaching Aerospace Structures and Materials to the World: Analysis of the edX MOOC Introduction to Aerospace Structures and Materials

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    Although aerospace traditionally has always had a multidisciplinary approach to engineering and design, the increasing complexity of aircraft and spacecraft and the rapid digitization within the aerospace industry has led to a large number of related engineering and scientific disciplines such as electrical engineers, computer scientist to work much more directly within the aerospace domain than before. Next to that there is a shortage of highly trained engineers worldwide to meet demand. As a result, there is a clear need to provide basic knowledge to non-aerospace engineers working in the field and to motivate and attract more people to engineering and aerospace in particular. This paper details how the creation of a Massive Open Online Course (MOOC) at an introductory level in Aerospace Structures and Materials provides an efficient and fit-for-purpose tool to achieve both aims. The paper will discuss the course design, the course set up, the course evaluation and how the course fits within the online learning philosophy of Delft University of Technology. It will use learning analytics to analyze our learners and their needs.Aerospace Structures & MaterialsStructural Integrity & CompositesAerospace Manufacturing TechnologiesTeaching & Learning Service
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