133 research outputs found

    A Review of the Properties of Nb3Sn and Their Variation with A15 Composition, Morphology and Strain State

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    This article gives an overview of the available literature on simplified, well defined (quasi-)homogeneous laboratory samples. After more than 50 years of research on superconductivity in Nb3Sn, a significant amount of results are available, but these are scattered over a multitude of publications. Two reviews exist on the basic properties of A15 materials in general, but no specific review for Nb3Sn is available. This article is intended to provide such an overview. It starts with a basic description of the Niobium-Tin intermetallic. After this it maps the influence of Sn content on the the electron-phonon interaction strength and on the field-temperature phase boundary. The literature on the influence of Cu, Ti and Ta additions will then be briefly summarized. This is followed by a review on the effects of grain size and strain. The article is concluded with a summary of the main results.Comment: Invited Topical Review for Superconductor, Science and Technology. Provisionally scheduled for July 200

    Consolidating Public Services in Anne Arundel County and the City of Annapolis: Impacts and Expenses

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    Combined final report for ECON454: Public Finance and Public Policy (Fall 2016). University of Maryland, College Park.This report is a collection of papers completed by students in the ECON454, Public Finance and Public Policy, who applied their students to a real world question as part of the PALS program. The class’s goal is understand the field of public finance and the relationship between economic theory and real world government policies. The goal of the PALS program is to use instructor expertise and student energy to advance sustainability in Maryland communities. In this effort, students explored the potential for consolidating public services in Anne Arundel County and the City of Annapolis, including the fiscal impacts and service level.Anne Arundel County & Annapoli

    Nutrition and the ageing brain: moving towards clinical applications

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    The global increases in life expectancy and population have resulted in a growing ageing population and with it a growing number of people living with age-related neurodegenerative conditions and dementia, shifting focus towards methods of prevention, with lifestyle approaches such as nutrition representing a promising avenue for further development. This overview summarises the main themes discussed during the 3 Symposium on "Nutrition for the Ageing Brain: Moving Towards Clinical Applications" held in Madrid in August 2018, enlarged with the current state of knowledge on how nutrition influences healthy ageing and gives recommendations regarding how the critical field of nutrition and neurodegeneration research should move forward into the future. Specific nutrients are discussed as well as the impact of multi-nutrient and whole diet approaches, showing particular promise to combatting the growing burden of age-related cognitive decline. The emergence of new avenues for exploring the role of diet in healthy ageing, such as the impact of the gut microbiome and development of new techniques (imaging measures of brain metabolism, metabolomics, biomarkers) are enabling researchers to approach finding answers to these questions. But the translation of these findings into clinical and public health contexts remains an obstacle due to significant shortcomings in nutrition research or pressure on the scientific community to communicate recommendations to the general public in a convincing and accessible way. Some promising programs exist but further investigation to improve our understanding of the mechanisms by which nutrition can improve brain health across the human lifespan is still required

    Review of gender, socioeconomic status, and ethnic background considerations reported in active school travel intervention studies

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    Introduction: Trends over the last half century have shown that fewer children today are engaging in active modes of travel to and from school than in previous generations. Interventions promoting active school travel (AST) can be effective at reversing these trends and increasing rates of AST among children. This paper aims to explore (1) how studies of AST interventions have considered or framed multiple equity factors, namely those related to gender, socioeconomic status (SES), and ethnic background, in the design and evaluation of AST interventions, and (2) to what extent studies of AST interventions report these equity considerations in their analyses, outcomes, programming, and discussions. Methods: Six databases were used (BIOSIS Previews, GeoBase, PubMed, SCOPUS, SPORTDiscus, and Web of Science) to obtain AST literature published between 2010 and 2019 from around the world. The inclusion criteria applied in this review included a focus on an AST intervention for children (aged 5–19 years), quantitative results, and a primary outcome related to AST. A total of 69 papers were included in the review. Results: Across AST intervention studies, equity considerations were scarcely reported. Among the explicit mentions, gender and socioeconomic status were reported most often compared to ethnic background. Some papers reported differential effects among groups. Gender, SES, and ethnic background were, when reported, generally considered as variables that were controlled for within study samples. Conclusions: Suggestions to address equity within studies of AST interventions include reporting equity considerations made throughout the intervention and its evaluation in the published article. Using and reporting equity frameworks to develop AST interventions and conducting sub-group analyses during evaluation allows for greater assessment of equity effects and improved utility and applicability of the AST intervention. Ensuring the integration of equity into AST literature is needed to support evidence-based and equitable practices

    Navigation and manipulation for autonomous underwater dismantling of offshore structures

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    Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015.Cataloged from PDF version of thesis.Includes bibliographical references (pages 95-99).The dismantling of offshore structures, known as decommissioning, is a complex task in the oil and gas industry, driven by strict environmental standards. As the environments in which decommissioning is necessary become more challenging, autonomy presents itself as a solution to conduct this work as cost-effectively and safely as possible, namely by taking Remotely Operated Vehicles (ROVs) and divers out of the equation. In this thesis, three avenues are researched in support of Autonomous Underwater Vehicles (AUVs) for decommissioning: navigation, attachment, and manipulation. First, the Iterative Closest Point method (ICP) is investigated as a means to correct position drift of an inertial navigation system, by using a previously obtained coarse map. Using real sonar data from a current decommissioning site in the Gulf of Mexico, the algorithm is able to reconcile the internally dead-reckoned pose of the vehicle with that calculated via ICP, to an accuracy of 7cm from a 100k-point sonar scan. Second, to attach lifting points to subsea scrap without bracing onto it, a single mechanism was designed to both drill and affix anchors in a single penetration, from a vehicle in free flight. A prototype was fabricated and its functionality verified. Third, to promote robust and stable robotic interactions using an industry standard non-backdrivable manipulator, a control law was developed to have the vehicle-manipulator system passively interact with its environment, by mimicking an arrangement of masses, springs, and dashpots. This control law was tested and analyzed in a simple experiment that achieved a 90% reduction in settling time.by Christian Livingston Welch.S.M
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