94 resultados para Ends of Spaces


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Existing studies have shown conclusively that the measured fibre reinforced polymer (FRP) rupture strain in FRP wrapped concrete columns is usually significantly smaller than the rupture strain obtained from flat coupon tests. One of the main causes for this phenomenon is the existence of geometrical discontinuities at both ends of the FRP sheets. This study proposes a new strengthening method in which continuous FRP spiral wrapping is used to eliminate strain concentrations due to the geometrical discontinuities and thus increase the FRP rupture strain at column failure. The effect of the spiral angle of FRP on the FRP rupture strain in FRP wrapped specimens was experimentally investigated. The test results indicate that the spiral wrapping with a small angle with respect to the column circumference can significantly increase the strain efficiency of FRP and thus enhance the axial compression capacity of the strengthened cylinders.

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What does material culture tell us about gendered identities and how does gender reveal the meaning of spaces and things?

If we look at the objects that we own, covet and which surround us in our everyday culture, there is a clear connection between ideas about gender and the material world. This book explores the material culture of the past to shed light on historical experiences and identities. Some essays focus on specific objects, such as an eighteenth-century jug or a twentieth-century powder puff, others on broader material environments, such as the sixteenth-century guild or the interior of a twentieth-century pub, while still others focus on the paraphernalia associated with certain actions, such as letter-writing or maintaining eighteenth-century men's hair.

Written by scholars in a range of history-related disciplines, the essays in this book offer exposés of current research methods and interests. These demonstrate to students how a relationship between material culture and gender is being addressed, while also revealing a variety of intellectual approaches and topics.

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Bin/Amphiphysin/Rvs (BAR) domain proteins control the curvature of lipid membranes in endocytosis, trafficking, cell motility, the formation of complex sub-cellular structures, and many other cellular phenomena. They form three-dimensional assemblies, which act as molecular scaffolds to reshape the membrane and alter its mechanical properties. It is unknown, however, how a protein scaffold forms and how BAR domains interact in these assemblies at protein densities relevant for a cell. In this work, we employ various experimental, theoretical and simulation approaches to explore how BAR proteins organize to form a scaffold on a membrane nanotube. By combining quantitative microscopy with analytical modeling, we demonstrate that a highly curving BAR protein endophilin nucleates its scaffolds at the ends of a membrane tube, contrary to a weaker curving protein centaurin, which binds evenly along the tube’s length. Our work implies that the nature of local protein-membrane interactions can affect the specific localization of proteins on membrane-remodeling sites. Furthermore, we show that amphipathic helices are dispensable in forming protein scaffolds. Finally, we explore a possible molecular structure of a BAR-domain scaffold using coarse-grained molecular dynamics simulations. Together with fluorescence microscopy, the simulations show that proteins need only to cover 30–40% of a tube’s surface to form a rigid assembly. Our work provides mechanical and structural insights into the way BAR proteins may sculpt the membrane as a high-order cooperative assembly in important biological processes. 

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