6,594 research outputs found

    Design and development of a deployable self-inflating adaptive membrane

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    Space structures nowadays are often designed to serve just one objective during their mission life, examples include truss structures that are used as support structures, solar sails for propulsion or antennas for communication. Each and every single one of these structures is optimized to serve just their distinct purpose and are more or less useless for the rest of the mission and therefore dead weight. By developing a smart structure that can change its shape and therefore adapt to different mission requirements in a single structure, the flexibility of the spacecraft can be increased by greatly decreasing the mass of the entire system. This paper will introduce such an adaptive structure called the Self-inflating Adaptive Membrane (SAM) concept which is being developed at the Advanced Space Concepts Laboratory of the University of Strathclyde. An idea presented in this paper is to adapt these basic changeable elements from nature’s heliotropism. Heliotropism describes a movement of a plant towards the sun during a day; the movement is initiated by turgor pressure change between adjacent cells. The shape change of the global structure can be significant by adding up these local changes induced by local elements, for example the cell’s length. To imitate the turgor pressure change between the motor cells in plants to space structures, piezoelectric micro pumps are added between two neighboring cells. A passive inflation technique is used for deploying the membrane at its destination in space. The trapped air in the spheres will inflate the spheres when subjected to vacuum, therefore no pump or secondary active deployment methods are needed. The paper will present the idea behind the adaption of nature’s heliotropism principle to space structures. The feasibility of the residual air inflation method is verified by LS-DYNA simulations and prototype bench tests under vacuum conditions. Additionally, manufacturing techniques and folding patterns are presented to optimize the actual bench test structure and to minimize the required storage volume. It is shown that through a bio-inspired concept, a high ratio of adaptability of the membrane can be obtained. The paper concludes with the design of a technology demonstrator for a sounding rocket experiment to be launched in March 2013 from the Swedish launch side Esrange

    Creating domestic building thermal performance ratings using smart meter data

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    Energy performance certificates (EPCs) are ratings of domestic building energy performance mandated across the European Union. Their aim is to provide a reliable assessment of a building’s energy performance whilst accounting for non-building effects such as weather and occupancy. Current rating methods, based on theoretical calculations, can introduce significant error from an inability to estimate real building performance. Other methods using real energy data cannot isolate building performance from other effects due to low data resolution. The installation of smart meters in large proportions of the housing stock in European Union member states presents an opportunity. Harnessing high-resolution energy data can create or inform building energy performance ratings with reduced error and at scale. This critical review explores the challenges and opportunities of using smart meter data in building energy ratings, focusing primarily on quantifying the thermal performance of the building and heating system. The research gaps in this emerging field are identified, including: demonstrating that the rating is truly independent of the behaviour of specific occupants; the additional data inputs that add most value in combination with smart meter data; and reducing uncertainty whilst limiting the complexity of the measurement and calculatio

    Environmental factors influence both abundance and genetic diversity in a widespread bird species.

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    Genetic diversity is one of the key evolutionary variables that correlate with population size, being of critical importance for population viability and the persistence of species. Genetic diversity can also have important ecological consequences within populations, and in turn, ecological factors may drive patterns of genetic diversity. However, the relationship between the genetic diversity of a population and how this interacts with ecological processes has so far only been investigated in a few studies. Here, we investigate the link between ecological factors, local population size, and allelic diversity, using a field study of a common bird species, the house sparrow (Passer domesticus). We studied sparrows outside the breeding season in a confined small valley dominated by dispersed farms and small-scale agriculture in southern France. Population surveys at 36 locations revealed that sparrows were more abundant in locations with high food availability. We then captured and genotyped 891 house sparrows at 10 microsatellite loci from a subset of these locations (N = 12). Population genetic analyses revealed weak genetic structure, where each locality represented a distinct substructure within the study area. We found that food availability was the main factor among others tested to influence the genetic structure between locations. These results suggest that ecological factors can have strong impacts on both population size per se and intrapopulation genetic variation even at a small scale. On a more general level, our data indicate that a patchy environment and low dispersal rate can result in fine-scale patterns of genetic diversity. Given the importance of genetic diversity for population viability, combining ecological and genetic data can help to identify factors limiting population size and determine the conservation potential of populations

    An Analysis of the Parasites of a Mid-winter Population of the Snowshoe Hare, Lepus americanus, on Insular Newfoundland During a Cyclical Peak

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    A mid-winter sample of 78 Snowshoe Hares (Lepus americanus) was collected during their cyclical peak in population from three eco-regions (Western Newfoundland, North Shore and Avalon Forest) on insular Newfoundland and was examined for the presence of enteric parasites. The length of the hares was significantly shorter in the Avalon Forest Region (n = 27) than those of the Western Newfoundland Region (n = 25) and North Shore Region (n = 26) samples (P ≤ 0.001 and P ≤ 0.003 respectively); however, no significant differences occurred for other morphological measurements. Four species of parasites, two cestodes (Mosgovoyia pectinata and Taenia pisiformis) and two nematodes (Obeliscoides cuniculi and Rauschia triangularis), were recovered. Taenia pisiformis was recovered from the North Shore eco-region only. No other significant differences with respect to their prevalence, intensity, mean intensity, relative density and dispersion between eco-regions were found. Within eco-regions, only R. triangularis showed a significantly higher value (P ≤ 0.027) for males and the prevalence of this species was lower than that previously reported. The occurrence of O. cuniculi was significantly different between the higher weight classes of hares and the prevalence of this species was higher than that previously reported. No trends for multiple infections were noted. The expansion of a new animal species, the Coyote, Canis latrans, to Newfoundland appeared to have had no effect on the diversity of parasites found in the hare

    Deep Hole States in Medium Mass Nuclei

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    Supported by the National Science Foundation and Indiana Universit

    Service user suicides and coroner's inquests

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    This is an Accepted Manuscript of an article published by Taylor & Francis in Criminal Justice Matters on 22nd May 2013, available online: DOI:10.1080/09627251.2013.805375The expansion of victimology in the 1980s produced a more nuanced understanding of victims and victimisation. Yet responses of government, criminal justice agencies, media and general public to victims are predictably and predominantly focused on victims of ‘conventional crime’. We challenge this perspective, thus widening the victimological lens. We discuss the impact of self-inflicted deaths and subsequent coronial inquests on practitioners working on behalf of the state

    Degenerate flag varieties: moment graphs and Schr\"oder numbers

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    We study geometric and combinatorial properties of the degenerate flag varieties of type A. These varieties are acted upon by the automorphism group of a certain representation of a type A quiver, containing a maximal torus T. Using the group action, we describe the moment graphs, encoding the zero- and one-dimensional T-orbits. We also study the smooth and singular loci of the degenerate flag varieties. We show that the Euler characteristic of the smooth locus is equal to the large Schr\"oder number and the Poincar\'e polynomial is given by a natural statistics counting the number of diagonal steps in a Schr\"oder path. As an application we obtain a new combinatorial description of the large and small Schr\"oder numbers and their q-analogues.Comment: 25 page
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