525 research outputs found

    NASA technology utilization survey on composite materials

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    NASA and NASA-funded contractor contributions to the field of composite materials are surveyed. Existing and potential non-aerospace applications of the newer composite materials are emphasized. Economic factors for selection of a composite for a particular application are weight savings, performance (high strength, high elastic modulus, low coefficient of expansion, heat resistance, corrosion resistance,), longer service life, and reduced maintenance. Applications for composites in agriculture, chemical and petrochemical industries, construction, consumer goods, machinery, power generation and distribution, transportation, biomedicine, and safety are presented. With the continuing trend toward further cost reductions, composites warrant consideration in a wide range of non-aerospace applications. Composite materials discussed include filamentary reinforced materials, laminates, multiphase alloys, solid multiphase lubricants, and multiphase ceramics. New processes developed to aid in fabrication of composites are given

    Anglo-Saxon England

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    Seasonal Consumptive Demand and Prey Use by Stocked Saugeyes in Ohio Reservoirs

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    Community structure and species composition may be strongly influenced by predator-prey interactions resulting from and leading to episodes of population abundance or scarcity. We quantified diets of stocked saugeyes (female walleye Sander vitreus × male sauger S. canadensis) and estimated biomass of their primary prey, gizzard shad Dorosoma cepedianum, in three Ohio reservoirs at quarterly intervals during July 2002-July 2003 to determine whether saugeye consumptive demand could exceed the supply of available gizzard shad prey, resulting in a shift to alternative prey. We incorporated water temperature and saugeye diet composition, growth, and mortality into walleye bioenergetics models, which allowed us to compare estimated prey-specific consumption rates by saugeyes with gizzard shad standing stocks estimated with acoustics. Spring and summer were critical seasons. During spring, gizzard shad biomass was low, saugeye consumptive demand was low, and saugeyes consumed primarily alternative prey. During summer, when age-0 gizzard shad became available as prey, saugeyes consumed similar proportions of gizzard shad and alternative prey. Saugeye cumulative consumptive demand in summer was high and approached the gizzard shad standing stock. However, during fall and winter, gizzard shad supply was adequate to support high (fall) or declining (winter) saugeye consumptive demand. Across reservoirs and seasons, saugeyes consumed alternative prey to varying degrees, primarily sunfishes Lepomis spp., yellow perch Perca flavescens, logperch Percina caprodes, and minnows Pimephales spp. Seasonal asynchrony between saugeye consumptive demand and gizzard shad biomass during spring and summer indicated that a saugeye population with high survival, growth, and consumptive demand will opportunistically increase use of prey other than gizzard shad. The manner in which saugeye predation quantitatively influences these prey species could not be assessed. However, overexploitation of gizzard shad prey appears to be unlikely at current saugeye population sizes, particularly considering the opportunistic use of alternative prey and the high reproductive potential of gizzard shad.Funding for this research was provided by the Ohio Department of Natural Resources, Division of Wildlife; Federal Aid in Sport Fish Restoration Project F-69-P, Fish Management in Ohio; and the Department of Evolution, Ecology, and Organismal Biology at The Ohio State University

    Comparison of whole house heat loss test methods under controlled conditions in six distinct retrofit scenarios

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    The accurate assessment of buildings to assess their performance across a range of parameters is an essential part of understanding both new and retrofit buildings. The growing understanding of the performance gap in terms of its assessment and characterisation relies on effective methods of analysis. Here, we evaluate an experimental whole house method, known as QUB. As with many whole building approaches the method establishes heat loss through transmission and ventilation losses. This study compares QUB against an alternative, established, whole house test known as coheating. It was applied in a whole house test facility under controlled conditions. The test property, a solid wall pre-1919 UK archetype, was retrofit using a set of commercially available products and then the retrofit was removed in stages. At each of these stages a QUB test, which commonly takes one night, and coheating test, which can take few weeks, were applied. The objective of the study was to provide a comparison between the new method and more established method in terms of accuracy. The two methods showed close agreement in terms of results, suggesting that the quicker test has great potential as a more practical and economic test. There were higher levels of uncertainty with the QUB method due to shorter measurement periods. The lack of full boundary conditions within the test facility should be considered a limitation in applying the findings directly to the field. However, this study indicates the potential for QUB in validating performance, warranting further investigation

    ‘Sons of athelings given to the earth’: Infant Mortality within Anglo-Saxon Mortuary Geography

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    FOR 20 OR MORE YEARS early Anglo-Saxon archaeologists have believed children are underrepresented in the cemetery evidence. They conclude that excavation misses small bones, that previous attitudes to reporting overlook the very young, or that infants and children were buried elsewhere. This is all well and good, but we must be careful of oversimplifying compound social and cultural responses to childhood and infant mortality. Previous approaches have offered methodological quandaries in the face of this under-representation. However, proportionally more infants were placed in large cemeteries and sometimes in specific zones. This trend is statistically significant and is therefore unlikely to result entirely from preservation or excavation problems. Early medieval cemeteries were part of regional mortuary geographies and provided places to stage events that promoted social cohesion across kinship systems extending over tribal territories. This paper argues that patterns in early Anglo-Saxon infant burial were the result of female mobility. Many women probably travelled locally to marry in a union which reinforced existing social networks. For an expectant mother, however, the safest place to give birth was with experience women in her maternal home. Infant identities were affected by personal and legal association with their mother’s parental kindred, so when an infant died in childbirth or months and years later, it was their mother’s identity which dictated burial location. As a result, cemeteries central to tribal identities became places to bury the sons and daughters of a regional tribal aristocracy
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