6,529 research outputs found

    Effect of area ratio on the performance of a 5.5:1 pressure ratio centrifugal impeller

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    A centrifugal impeller which was initially designed for a pressure ratio of approximately 5.5 and a mass flow rate of 0.959 kg/sec was tested with a vaneless diffuser for a range of design point impeller area ratios from 2.322 to 2.945. The impeller area ratio was changed by successively cutting back the impeller exit axial width from an initial value of 7.57 mm to a final value of 5.97 mm. In all, four separate area ratios were tested. For each area ratio a series of impeller exit axial clearances was also tested. Test results are based on impeller exit surveys of total pressure, total temperature, and flow angle at a radius 1.115 times the impeller exit radius. Results of the tests at design speed, peak efficiency, and an exit tip clearance of 8 percent of exit blade height show that the impeller equivalent pressure recovery coefficient peaked at a design point area ratio of approximately 2.748 while the impeller aerodynamic efficiency peaked at a lower value of area ratio of approximately 2.55. The variation of impeller efficiency with clearance showed expected trends with a loss of approximately 0.4 points in impeller efficiency for each percent increase in exit axial tip clearance for all impellers tested

    Developing a Pilot Case and Modelling the Development of a Large European CO<sub>2</sub> Transport Infrastructure -The GATEWAY H2020 Project

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    The H2020 GATEWAY project aims to develop a comprehensive model Pilot Case which, intentionally, will pave the ground for CCS deployment in Europe. It will result from the assessment of, technical, commercial, judicial and societal issues related to a future CO2 transport infrastructure. The Pilot Case derived on this basis, will emphasize a gateway for CO2 transport in the North Sea Basin. Four potential pilot cases have been evaluated through a combination of techno-economic modelling of the individual cases and evaluation against more qualitative criteria. The chosen Pilot Case, Rotterdam Nucleus, will be refined and developed during the remaining period of the GATEWAY project. To maximise impact, the GATEWAY project adapts its work to lay the foundation for a future application to a European ‘Project of Common Interest’ (PCI). Continuous dialogue with the most relevant stakeholders is an important part of GATEWAY, as a Coordination and Support Action (CSA) H2020 project

    Bounds on Lorentz and CPT Violation from the Earth-Ionosphere Cavity

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    Electromagnetic resonant cavities form the basis of many tests of Lorentz invariance involving photons. The effects of some forms of Lorentz violation scale with cavity size. We investigate possible signals of violations in the naturally occurring resonances formed in the Earth-ionosphere cavity. Comparison with observed resonances places the first terrestrial constraints on coefficients associated with dimension-three Lorentz-violating operators at the level of 10^{-20} GeV.Comment: 8 pages REVTe

    Magnetofossil Spike During the Paleocene-Eocene Thermal Maximum: Ferromagnetic Resonance, Rock Magnetic, and Electron Microscopy Evidence from Ancora, New Jersey, USA

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    Previous workers identified a magnetically anomalous clay layer deposited on the northern United States Atlantic Coastal Plain during the Paleocene-Eocene Thermal Maximum (PETM). The finding inspired the highly controversial hypothesis that a cometary impact triggered the PETM. Here we present ferromagnetic resonance (FMR), isothermal and anhysteretic remanent magnetization, first order reversal curve, and transmission electron microscopy analyses of late Paleocene and early Eocene sediments in drillcore from Ancora, New Jersey. A novel paleogeographic analysis applying a recent paleomagnetic pole from the Faeroe Islands indicates that New Jersey during the initial Eocene had a ~6-9 degrees lower paleolatitude (~27.3 degrees for Ancora) and a more zonal shoreline trace than in conventional reconstructions. Our investigations of the PETM clay from Ancora reveal abundant magnetite nanoparticles bearing signature traits of crystals produced by magnetotactic bacteria. This result, the first identification of ancient biogenic magnetite using FMR, argues that the anomalous magnetic properties of the PETM sediments are not produced by an impact. They instead reflect environmental changes along the eastern margin of North America during the PETM that led to enhanced production and/or preservation of magnetofossils

    AN INTERACTIVE ILLUSTRATION OF FARM PROGRAM PROVISIONS

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    Explaining the details and the impacts of government program provisions to agricultural producers can be a challenge for extension educators. This paper introduces a visual interactive tool that demonstrates the calculations of government payments established in the 2002 farm bill. Additionally, the paper explains how the tool is created in Microsoft® Excel and may be used in other areas.Agricultural and Food Policy,

    Representative Farms Economic Outlook for the November 2002 FAPRI/AFPC Baseline

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    The farm level economic impacts of the Farm Security and Rural Investment Act of 2002 on representative crop and livestock operations are projected in this report. The analysis was conducted over the 2001-2007 planning horizon using FLIPSIM, AFPC’s whole farm simulation model. Data to simulate farming operations in the nation’s major production regions came from two sources: - Producer panel cooperation to develop economic information to describe and simulate representative crop, livestock, and dairy farms. - Projected prices, policy variables, and input inflation rates from the Food and Agricultural Policy Research Institute (FAPRI) November 2002 Baseline. The FLIPSIM policy simulation model incorporates the historical risk faced by farmers for prices and production. This report presents the results of the November 2002 Baseline in a risk context using selected simulated probabilities and ranges for annual net cash farm income values. The probability of a farm experiencing annual cash flow deficits and the probability of a farm losing real net worth are included as indicators of the cash flow and equity risks facing farms through the year 2007.Agribusiness, Agricultural and Food Policy, Crop Production/Industries,

    Neuron numbers increase in the human amygdala from birth to adulthood, but not in autism.

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    Remarkably little is known about the postnatal cellular development of the human amygdala. It plays a central role in mediating emotional behavior and has an unusually protracted development well into adulthood, increasing in size by 40% from youth to adulthood. Variation from this typical neurodevelopmental trajectory could have profound implications on normal emotional development. We report the results of a stereological analysis of the number of neurons in amygdala nuclei of 52 human brains ranging from 2 to 48 years of age [24 neurotypical and 28 autism spectrum disorder (ASD)]. In neurotypical development, the number of mature neurons in the basal and accessory basal nuclei increases from childhood to adulthood, coinciding with a decrease of immature neurons within the paralaminar nucleus. Individuals with ASD, in contrast, show an initial excess of amygdala neurons during childhood, followed by a reduction in adulthood across nuclei. We propose that there is a long-term contribution of mature neurons from the paralaminar nucleus to other nuclei of the neurotypical human amygdala and that this growth trajectory may be altered in ASD, potentially underlying the volumetric changes detected in ASD and other neurodevelopmental or neuropsychiatric disorders

    Vergleich einer neuen Zweinutzungs- mit einer Legehybride bzgl. Tiergerechtheit und Legeleistung

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    Aim of the study was to compare a new dual purpose hybrid strain (Lohmann dual, LD) with a layer strain (Lohmann Brown plus, LB) under organic conditions. 400 Laying hens were kept in 2 mobile houses (2 x 4 groups of 50 hens). Egg production and egg weight were higher in LBP. LBP hens used the pasture more than LD. However, foraging was the main activity in both strains. LD hens showed less behavioral activity within the hen house. Plumage condition was better in LBP
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