17,176 research outputs found

    Contributions of Vacuum and Plasmon Modes to the Force on a Small Sphere near a Plate

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    The force on a small sphere with a plasma model dielectric function and in the presence of a perfectly reflecting plane is considered. The contribution of both the vacuum modes of the quantized electromagnetic field and of plasmon modes in the sphere are discussed. In the case that the plasmon modes are in their ground state, quasi-oscillatory terms from the vacuum and plasmon parts cancel one another, leading a monotonic attractive force. If the plasmon modes are not in the ground state, the net force is quasi-oscillatory. In both cases, the sphere behaves in the same way as does an atom in either its ground state or an excited state.Comment: 7 pages, no figures, talk presented at "Quantum Fields under External Conditions - 2005", Barcelona, Spain, September 200

    Time to address the double inequality of differences in dietary intake between Scotland and England

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    Geographical disparities in health outcomes have been evident across the UK for decades. There is limited recent analysis on the dietary differences between Scotland and England that might go some way to explain these health differences. This study aimed to assess whether, and to what degree, aspects of diet and nutrition differ between Scottish and English populations, specifically between those with similar household incomes. Twelve years of UK food purchase data (2001-2012) were pooled and used to estimate household level consumption data for Scotland and England. Population mean food consumption and nutrient intakes were estimated, adjusting for known confounders (year, age of household reference person, age they left full-time education and income). Comparison was also made within equivalised income quintiles. Analysis showed that the foods and nutrients that should be increased in the diet (highlighted in the Scottish Dietary Goals) were lower in Scotland than England (e.g. fruit and vegetables 267g/day (99%CI 259-274g/day) vs. 298g/day (99%CI 296-301g/day), P<0.001). Likewise, foods and drinks linked with poor health outcomes were higher in Scotland. These regional inequalities in diet were even more pronounced in the lower income groups (e.g. red and processed meat consumption in the lowest income quintile was 65g/day (99% CI 61-69g/day) in Scotland vs. 58g/day (99% CI 57-60g/day) in England, P<0.001, but similar in the highest income quintile (58g/day (99%CI 54-61 g/day) vs. 59g/day (99% CI 58-60 g/day) respectively). A poorer diet in Scotland compared to England, particularly among disadvantaged groups, may contribute to differences in excess mortality between countries

    Identifying dietary differences between Scotland and England:a rapid review of the literature

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    Rates of premature mortality have been higher in Scotland than in England since the 1970s. Given the known association of diet with chronic disease, the study objective was to identify and synthesise evidence on current and historical differences in food and nutrient intakes in Scotland and England.A rapid review of the peer-reviewed and grey literature was carried out. After an initial scoping search, Medline, CINAHL, Embase and Web of Science were searched. Relevant grey literature was also included. Inclusion criteria were: any date; measures of dietary intake; representative populations; cross-sectional or observational cohort studies; and English-language publications. Study quality was assessed using the Quality Assessment Tool for Observational Cohort and Cross-sectional Studies. A narrative synthesis of extracted information was conducted.Fifty publications and reports were included in the review. Results indicated that children and adults in Scotland had lower intakes of vegetables and vitamins compared with those living in England. Higher intakes of salt in Scotland were also identified. Data were limited by small Scottish samples, difficulty in finding England-level data, lack of statistical testing and adjustment for key confounders.Further investigation of adequately powered and analysed surveys is required to examine more fully dietary differences between Scotland and England. This would provide greater insight into potential causes of excess mortality in Scotland compared with England and suitable policy recommendations to address these inequalities

    A review of residual stress analysis using thermoelastic techniques

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    Thermoelastic Stress Analysis (TSA) is a full-field technique for experimental stress analysis that is based on infra-red thermography. The technique has proved to be extremely effective for studying elastic stress fields and is now well established. It is based on the measurement of the temperature change that occurs as a result of a stress change. As residual stress is essentially a mean stress it is accepted that the linear form of the TSA relationship cannot be used to evaluate residual stresses. However, there are situations where this linear relationship is not valid or departures in material properties due to manufacturing procedures have enabled evaluations of residual stresses. The purpose of this paper is to review the current status of using a TSA based approach for the evaluation of residual stresses and to provide some examples of where promising results have been obtained

    Experience and Assessment of the DOE/NASA Mod-1 2000 Kw Wind Turbine Generator at Boone, North Carolina

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    The Mod 1 program objectives are defined. The Mod 1 wind turbine is described. In addition to the steel blade operated on the wind turbine, a composite blade was designed and manufactured. During the early phase of the manufacturing cycle of Mod 1A configuration was designed that identified concepts such as partial span control, a soft tower, and upwind teetered rotors that were incorporated in second and third generation industry designs. The Mod 1 electrical system performed as designed, with voltage flicker characteristics within acceptable utility limits

    Computer program to predict noise of general aviation aircraft: User's guide

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    Program NOISE predicts General Aviation Aircraft far-field noise levels at FAA FAR Part 36 certification conditions. It will also predict near-field and cabin noise levels for turboprop aircraft and static engine component far-field noise levels

    Casimir-Polder forces, boundary conditions and fluctuations

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    We review different aspects of the atom-atom and atom-wall Casimir-Polder forces. We first discuss the role of a boundary condition on the interatomic Casimir-Polder potential between two ground-state atoms, and give a physically transparent interpretation of the results in terms of vacuum fluctuations and image atomic dipoles. We then discuss the known atom-wall Casimir-Polder force for ground- and excited-state atoms, using a different method which is also suited for extension to time-dependent situations. Finally, we consider the fluctuation of the Casimir-Polder force between a ground-state atom and a conducting wall, and discuss possible observation of this force fluctuation.Comment: 5 page
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