18,163 research outputs found

    The aerodynamic characteristics of a model wing having a split flap deflected downward and moved to the rear

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    Tests were made on a model wing with three different sized split trailing-edged flaps, in the NACA 7 by 10 foot wind tunnel. The flaps were formed of the lower rear portion of the wing and were rotated downward about axes at their front edges. The lift, drag, and center of pressure were measured with the axis in its original position and also with it moved back in even steps to the trailing edge of the main wing, giving in effect an increase in area. The split flaps when deflected about their original axis locations gave slightly higher maximum lift coefficients than conventional trailing-edge flaps, and the lift coefficients were increased still further by moving the axes toward the rear. The highest value of C(sub L max), which was obtained with the largest flap hinged at 90 per cent of the chord from the leading edge, was 2.52 as compared with 1.27 for the basic wing

    Measuring Regional Economic Impacts from Wildfire: Case Study of Southeast Oregon Cattle-Ranching Business

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    public grazing, regional economic impact, Social Accounting Matrix, Southeast Oregon, wildfire

    The Inner Halo of M87: A First Direct View of the Red-Giant Population

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    An unusually deep (V,I) imaging dataset for the Virgo supergiant M87 with the Hubble Space Telescope ACS successfully resolves its brightest red-giant stars, reaching M_I(lim) = -2.5. After assessing the photometric completeness and biasses, we use this material to estimate the metallicity distribution for the inner halo of M87, finding that the distribution is very broad and likely to peak near [m/H] ~ -0.4 and perhaps higher. The shape of the MDF strongly resembles that of the inner halo for the nearby giant E galaxy NGC 5128. As a byproduct of our study, we also obtain a preliminary measurement of the distance to M87 with the TRGB (red-giant branch tip) method; the result is (m-M)_0 = 31.12 +- 0.14 (d = 16.7 +- 0.9 Mpc). Averaging this result with three other recent techniques give a weighted mean d(M87) = (16.4 +- 0.5) Mpc.Comment: In press for Astronomy and Astrophysic

    Bias Analysis in Entropy Estimation

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    We consider the problem of finite sample corrections for entropy estimation. New estimates of the Shannon entropy are proposed and their systematic error (the bias) is computed analytically. We find that our results cover correction formulas of current entropy estimates recently discussed in literature. The trade-off between bias reduction and the increase of the corresponding statistical error is analyzed.Comment: 5 pages, 3 figure

    Nonequilibrium phase transition on a randomly diluted lattice

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    We show that the interplay between geometric criticality and dynamical fluctuations leads to a novel universality class of the contact process on a randomly diluted lattice. The nonequilibrium phase transition across the percolation threshold of the lattice is characterized by unconventional activated (exponential) dynamical scaling and strong Griffiths effects. We calculate the critical behavior in two and three space dimensions, and we also relate our results to the recently found infinite-randomness fixed point in the disordered one-dimensional contact process.Comment: 4 pages, 1 eps figure, final version as publishe

    Brain Trust: Students for Students: VCU to RPS Mentorship Program

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    As a public, urban research institution, Virginia Commonwealth University embraces the importance of developing university-community partnerships that generate innovative solutions to societal challenges and prepare engaged citizens of tomorrow. The Students for Students: VCU to RPS Mentorship Program provides a model that will connect current VCU students to current Richmond Public Schools (RPS) students through a formal, multi-year mentorship. The ultimate goal of this program is to support and positively influence RPS students, while providing current VCU students with an opportunity to give back to the community while developing their mentorship skills. The mentoring relationship will seek to motivate RPS sophomores, juniors and seniors to improve school performance, graduate on time, and craft a post-high school path
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