2,312 research outputs found

    Weekday Religious Instruction in the Public Schools of Omaha, Nebraska

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    The investigation to be reported was undertaken in an effort to determine why the release-time religious education in the Omaha public schools through so-called Weekday Church Schools was discontinued after one year of operation. The promoters of the project reported that hardly a more favorable situation for Weekday Church Schools could have been found and yet it had to be abandoned because of lack of funds

    Vapor feeding of liquid metal cathodes

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    Modified liquid metal cathode apparatus permits vapor feeding in the diffuse-spot pattern mode. Vapor-fed cathode has advantages over liquid-fed systems

    High-temperature LM cathode ion thrusters Quarterly progress report, 5 May - 4 Aug. 1968

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    Design and operation of high temperature liquid mercury cathode ion thruster

    High-temperature LM cathode ion thrusters Quarterly progress report, 5 Feb. - 4 May 1968

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    Poiseuille flow measurements for high temperature liquid metal cathode ion thruster

    High-temperature liquid-mercury cathodes for ion thrusters Quarterly progress report, 1 Dec. 1966 - 28 Feb. 1967

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    High temperature liquid mercury cathodes for ion thrusters - thermal design analysi

    Suggestions for Better Integrating ICT enhanced

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    In: A.J. Kallenberg and M.J.J.M. van de Ven (Eds), 2002, The New Educational Benefits of ICT in Higher Education: Proceedings. Rotterdam: Erasmus Plus BV, OECR ISBN 90-9016127-9The particular situation of academic teachers and learners in campus-based Higher Education today gives rise to the idea of an integrated dimensional framework for instructional design (ID). We will relate it to the potential of ICT, especially for blended learning. It is argued that the framework can become the kernel of an advisory system addressing current needs of practitioners in campus-based Higher Education by taking advantage of research evidence

    Tidal controls on trace gas dynamics in a seagrass meadow of the Ria Formosa lagoon (southern Portugal)

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    Coastal zones are important source regions for a variety of trace gases, including halocarbons and sulfur-bearing species. While salt marshes, macroalgae and phyto-plankton communities have been intensively studied, little is known about trace gas fluxes in seagrass meadows. Here we report results of a newly developed dynamic flux chamber system that can be deployed in intertidal areas over full tidal cycles allowing for highly time-resolved measurements. The fluxes of CO2, methane (CH4) and a range of volatile organic compounds (VOCs) showed a complex dynamic mediated by tide and light. In contrast to most previous studies, our data indicate significantly enhanced fluxes during tidal immersion relative to periods of air exposure. Short emission peaks occurred with onset of the feeder current at the sampling site. We suggest an overall strong effect of advective transport processes to explain the elevated fluxes during tidal immersion. Many emission estimates from tidally influenced coastal areas still rely on measurements carried out during low tide only. Hence, our results may have significant implications for budgeting trace gases in coastal areas. This dynamic flux chamber system provides intensive time series data of community respiration (at night) and net community production (during the day) of shallow coastal systems.German Federal Ministry of Education and Research (BMBF) [03F0611E, 03F0662E]; EU FP7 ASSEMBLE research infrastructure initiative

    Statistical analysis of coherent structures in transitional pipe flow

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    Numerical and experimental studies of transitional pipe flow have shown the prevalence of coherent flow structures that are dominated by downstream vortices. They attract special attention because they contribute predominantly to the increase of the Reynolds stresses in turbulent flow. In the present study we introduce a convenient detector for these coherent states, calculate the fraction of time the structures appear in the flow, and present a Markov model for the transition between the structures. The fraction of states that show vortical structures exceeds 24% for a Reynolds number of about Re=2200, and it decreases to about 20% for Re=2500. The Markov model for the transition between these states is in good agreement with the observed fraction of states, and in reasonable agreement with the prediction for their persistence. It provides insight into dominant qualitative changes of the flow when increasing the Reynolds number.Comment: 11 pages, 26 (sub)figure
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