81,944 research outputs found

    Boundary layer, skin friction, and boattail pressure measurements from the YF-12 airplane at Mach numbers up to 3

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    In-flight measurements of boundary layer and skin friction data were made on YF-12 airplanes for Mach numbers between 2.0 and 3.0. Boattail pressures were also obtained for Mach numbers between 0.7 and 3.0 with Reynolds numbers up to four hundred million. Boundary layer data measured along the lower fuselage centerline indicate local displacement and momentum thicknesses can be much larger than predicted. Skin friction coefficients measured at two of five lower fuselage stations were significantly less than predicted by flat plate theory. The presence of large differences between measured boattail pressure drag and values calculated by a potential flow solution indicates the presence of vortex effects on the upper boattail surface. At both subsonic and supersonic speeds, pressure drag on the longer of two boattail configurations was equal to or less than the pressure drag on the shorter configuration. At subsonic and transonic speeds, the difference in the drag coefficient was on the order of 0.0008 to 0.0010. In the supersonic cruise range, the difference in the drag coefficient was on the order of 0.002. Boattail drag coefficients are based on wing reference area

    Padlet:An online tool for learner engagement and collaboration

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    Boredom at work:What, why, and what then?

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    Why don't they learn?

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    From foot-slogging to call centres and direct mail: A framework for analysing the development of district-level campaigning

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    Drawing upon ideas formulated with national-level campaigning in mind and also analyses of district or local-level campaigning, a conceptual framework to assist in analysing the development of district-level campaigning is presented. The proposed framework is further amplified, explained and tested using quantitative and qualitative data collected at British General Elections between 1992 and 2005. Various aspects of district (constituency) campaigning in Britain are examined and the extent of change over four General Elections analysed. In broad terms, the data show a good fit with the framework, which offers a useful way of thinking about developments in campaigning both within and across countries

    Fractal Droplets in Two Dimensional Spin Glasses

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    The two-dimensional Edwards-Anderson model with Gaussian bond distribution is investigated at T=0 with a numerical method. Droplet excitations are directly observed. It turns out that the averaged volume of droplets is proportional to l^D with D = 1.80(2) where l is the spanning length of droplets, revealing their fractal nature. The exponent characterizing the l dependence of the droplet excitation energy is estimated to be -0.42(4), clearly different from the stiffness exponent for domain wall excitations.Comment: 4 pages 4 figure

    Party membership and campaign activity in Britain: The impact of electoral performance

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    The article examines the impact of electoral results on party membership and activity. Previous studies have focused on the long-term effects of electoral success or failure, suggesting that they may produce a spiral of demobilization or mobilization. The article shows that the dramatic change of electoral fortunes experienced by British parties at the 1997 general election broke this spiral, with the outcome leading to significant changes in the health and activity of local parties. It is concluded that dramatic election results can have significant implications for party organization

    Experiencing Science, An Introduction to Real Methods of Science for the Preservice Teacher

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    The scientific method presented in the middle school classroom introduces the experimental approach of science in a way that may actually bear little resemblance to the processes actually used by working scientists. Teachers equipped with an insight into the motivations, philosophy, tools, and culture of science will better convey an accurate and positive picture of science as a critically important human endeavor. The Experiencing Science course was designed to answer the challenge of giving the pre-service teacher and decision-maker better insight into actual processes used by scientists, in the context of each of the major disciplines
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