7,156 research outputs found

    Laser velocimeter systems analysis applied to a flow survey above a stalled wing

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    A laser velocimeter operating in the backscatter mode was used to survey the flow above a stalled wing. Polarization was used to separate the two orthogonal velocity components of the fringe-type laser velocimeter, and digital counters were used for data processing. The velocities of the kerosene seed particles were measured with less than 2 percent uncertainty. The particle velocity measurements were collected into histograms. The flow field survey was carried out above an aspect-ratio-8 stalled wing with an NACA 0012 section. The angle of attack was 19.5 deg, the Mach number was 0.49, and the Reynolds number was 1,400,000. The flow field was characterized by the periodic shedding of discrete vortices from near the crest of the airfoil

    Wavelength Dependent PSFs and their impact on Weak Lensing Measurements

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    We measure and model the wavelength dependence of the PSF in the Hyper Suprime-Cam (HSC) Subaru Strategic Program (SSP) survey. We find that PSF chromaticity is present in that redder stars appear smaller than bluer stars in the g,r,g, r, and ii-bands at the 1-2 per cent level and in the zz and yy-bands at the 0.1-0.2 per cent level. From the color dependence of the PSF, we fit a model between the monochromatic PSF trace radius, RR, and wavelength of the form R(λ)λbR(\lambda)\propto \lambda^{b}. We find values of bb between -0.2 and -0.5, depending on the epoch and filter. This is consistent with the expectations of a turbulent atmosphere with an outer scale length of 10100\sim 10-100 m, indicating that the atmosphere is dominating the chromaticity. We find evidence in the best seeing data that the optical system and detector also contribute some wavelength dependence. Meyers and Burchat (2015) showed that bb must be measured to an accuracy of 0.02\sim 0.02 not to dominate the systematic error budget of the Large Synoptic Survey Telescope (LSST) weak lensing (WL) survey. Using simple image simulations, we find that bb can be inferred with this accuracy in the rr and ii-bands for all positions in the LSST field of view, assuming a stellar density of 1 star arcmin2^{-2} and that the optical PSF can be accurately modeled. Therefore, it is possible to correct for most, if not all, of the bias that the wavelength-dependent PSF will introduce into an LSST-like WL survey.Comment: 14 pages, 10 figures. Submitted to MNRAS. Comments welcom

    The Effect of Price-Insulating Poll Policies on Exchange Rate Analysis

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    A model derived to compute exchange rate effects on trade uses foreign internal demand elasticities and price transmission elasticities which account for government price-insulating policies Appreciation of the Japanese yen relative to the dollar is analyzed for impacts on Japanese imports of U S wheat, feed grains, and soybeans

    Children's construction task performance and spatial ability: controlling task complexity and predicting mathematics performance.

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    This paper presents a methodology to control construction task complexity and examined the relationships between construction performance and spatial and mathematical abilities in children. The study included three groups of children (N = 96); ages 7-8, 10-11, and 13-14 years. Each group constructed seven pre-specified objects. The study replicated and extended previous findings that indicated that the extent of component symmetry and variety, and the number of components for each object and available for selection, significantly predicted construction task difficulty. Results showed that this methodology is a valid and reliable technique for assessing and predicting construction play task difficulty. Furthermore, construction play performance predicted mathematical attainment independently of spatial ability

    Some homogenization and corrector results for nonlinear monotone operators

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    This paper deals with the limit behaviour of the solutions of quasi-linear equations of the form \ \ds -\limfunc{div}\left(a\left(x, x/{\varepsilon _h},Du_h\right)\right)=f_h on Ω\Omega with Dirichlet boundary conditions. The sequence (εh)(\varepsilon _h) tends to 00 and the map a(x,y,ξ)a(x,y,\xi ) is periodic in yy, monotone in ξ\xi and satisfies suitable continuity conditions. It is proved that uhuu_h\rightarrow u weakly in H01,2(Ω)H_0^{1,2}(\Omega ), where uu is the solution of a homogenized problem \ -\limfunc{div}(b(x,Du))=f on Ω\Omega . We also prove some corrector results, i.e. we find (Ph)(P_h) such that DuhPh(Du)0Du_h-P_h(Du)\rightarrow 0 in L2(Ω,Rn)L^2(\Omega ,R^n)

    Law of One Price in International Commodity Markets: A Fractional Cointegration Analysis

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    The Law of One Price (LOP) is an important component of most, if not all, international trade models because this assumption allows researchers to use a single representative price for all regions. This paper examines the long-run LOP for international commodity prices using a generalized notion of cointegration called fractional cointegration. This analysis is applied to nine pairs of price series, supporting the existence of LOP in eight cases

    Recent Legal Literature

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    Noyes: American Railroad Rates; Meyer: Railway Legislation in the United States; Diccy: Lectures on the Relation between Law and Public Opinion in England During the Nineteenth Century; Page: Law of Contracts; Camp: The Encyclopaedia of Evidence; Clement: Fire Insurance as a Void Conttract and as Affected by Construction and Waiver of Estoppel, including miscellaneous provisions and an analysis and comparison of the various standard forms, all reduced to rules with the relevant statutory provisions of all the states. Volume II.; Woodruff: A Selection of Cases on Domestic Relations and the Law of Persons; Kinkead: Jurisprudence Law and Ethics; Schouler: Law of the Domestic Relations Embracing Husband and Wife, Parent and Child, Fuardian and Ward, Infancy and Master and Servant; Hoyt (ed.): Report of the Colorado Bar Association. Volume 8
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