20,281 research outputs found

    Two dimensional recursive digital filters for near real time image processing

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    A program was designed toward the demonstration of the feasibility of using two dimensional recursive digital filters for subjective image processing applications that require rapid turn around. The concept of the use of a dedicated minicomputer for the processor for this application was demonstrated. The minicomputer used was the HP1000 series E with a RTE 2 disc operating system and 32K words of memory. A Grinnel 256 x 512 x 8 bit display system was used to display the images. Sample images were provided by NASA Goddard on a 800 BPI, 9 track tape. Four 512 x 512 images representing 4 spectral regions of the same scene were provided. These images were filtered with enhancement filters developed during this effort

    New GOES satellite synchronized time code generation

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    The TRAK Systems' GOES Satellite Synchronized Time Code Generator is described. TRAK Systems has developed this timing instrument to supply improved accuracy over most existing GOES receiver clocks. A classical time code generator is integrated with a GOES receiver

    Aerodynamic characteristics of the 40- by 80/80- by 120-foot wind tunnel at NASA Ames Research Center

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    The design and testing of vane sets and air-exchange inlet for the 40 x 80/80 x 120-ft wind tunnel at NASA Ames are reported. Boundary-layer analysis and 2D and 3D inviscid panel codes are employed in computer models of the system, and a 1/10-scale 2D facility and a 1/50-scale 3D model of the entire wind tunnel are used in experimental testing of the vane sets. The results are presented in graphs, photographs, drawings, and diagrams are discussed. Generally good agreement is found between the predicted and measured performance

    A connection between the Camassa-Holm equations and turbulent flows in channels and pipes

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    In this paper we discuss recent progress in using the Camassa-Holm equations to model turbulent flows. The Camassa-Holm equations, given their special geometric and physical properties, appear particularly well suited for studying turbulent flows. We identify the steady solution of the Camassa-Holm equation with the mean flow of the Reynolds equation and compare the results with empirical data for turbulent flows in channels and pipes. The data suggests that the constant α\alpha version of the Camassa-Holm equations, derived under the assumptions that the fluctuation statistics are isotropic and homogeneous, holds to order α\alpha distance from the boundaries. Near a boundary, these assumptions are no longer valid and the length scale α\alpha is seen to depend on the distance to the nearest wall. Thus, a turbulent flow is divided into two regions: the constant α\alpha region away from boundaries, and the near wall region. In the near wall region, Reynolds number scaling conditions imply that α\alpha decreases as Reynolds number increases. Away from boundaries, these scaling conditions imply α\alpha is independent of Reynolds number. Given the agreement with empirical and numerical data, our current work indicates that the Camassa-Holm equations provide a promising theoretical framework from which to understand some turbulent flows.Comment: tex file, 29 pages, 4 figures, Physics of Fluids (in press

    High-performance light-weight electrodes for hydrogen-oxygen fuel cells

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    High performance light weight electrodes for hydrogen oxygen fuel cell

    Imperfect identity

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    Questions of identity over time are often hard to answer. A long tradition has it that such questions are somehow soft: they have no unique, determinate answer, and disagreements about them are merely verbal. I argue that this claim is not the truism it is taken to be. Depending on how it is understood, it turns out either to be false or to presuppose a highly contentious metaphysical claim

    NRGY 101.01: Introduction to Sustainable Energy

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    NRGY 102.01A: Introduction to Sustainable Energy II

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    N, L Distributions For Electron-Capture From H(1s) By C⁶⁺and O8+

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    Total cross sections for electron-capture from the ground state of hydrogen by C6+(40, 50, 60, 80, 100 and 120 keV/u) and O8+(40, 50, 60, 80, 100, 120 and 140keV/u) have been calculated using the classical-trajectory Monte Carlo (CTMC) technique. We tabulate these cross sections as a function of projectile energy for (i) capture to all product states, (ii) capture to product n-levels, and (iii) capture to product n, l-levels. The results of these calculations agree with and extend previous CTMC n, ldistribution results. © 1989 IOP Publishing Ltd
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