42,344 research outputs found

    Computer program to determine the irrotational nozzle admittance

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    Irrotational nozzle admittance is the boundary condition that must be satisfied by combustor flow oscillations at nozzle entrance. Defined as the ratio of axial velocity perturbation to the pressure perturbation at nozzle entrance, nozzle admittance can also be used to determine whether wave motion in nozzle under consideration adds or removes energy from combustor oscillations

    Measuring field concentrations of nitrogen dioxide using diffusion tubes

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    Design and fabrication of metallic thermal protection systems for aerospace vehicles

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    A program was conducted to develop a lightweight, efficient metallic thermal protection system (TPS) for application to future shuttle-type reentry vehicles, advanced space transports, and hypersonic cruise vehicles. Technical requirements were generally derived from the space shuttle. A corrugation-stiffened beaded-skin TPS design was used as a baseline. The system was updated and modified to incorporate the latest technology developments and design criteria. The primary objective was to minimize mass for the total system

    Development of advanced fuel cell system (phase 4)

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    For abstract, see N76-23686

    Gravothermal Catastrophe, an Example

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    This work discusses gravothermal catastrophe in astrophysical systems and provides an analytic collapse solution which exhibits many of the catastrophe properties. The system collapses into a trapped surface with outgoing energy radiated to a future boundary, and provides an example of catastrophic collapse.Comment: To appear in Phys. Rev.

    On The Relevance Of Fair Sampling Assumption In The Recent Bell Photonic Experiments

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    In the experimental verification of Bell's inequalities in real photonic experiments, it is generally believed that the so-called fair sampling assumption (which means that a small fraction of results provide a fair statistical sample) has an unavoidable role. Here, we want to show that the interpretation of these experiments could be feasible, if some different alternative assumptions other than the fair sampling were used. For this purpose, we derive an efficient Bell-type inequality which is a CHSH-type inequality in real experiments. Quantum mechanics violates our proposed inequality, independent of the detection-efficiency problems.Comment: 13 pages, no figure, one table. Last versio

    Cultivation and use of bryophytes as experimental material

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    Bryophytes can be grown successfully if keptmoist, supplied with nutrients, and out of direct sunlight. They remain greener on peat than on sand. However, difficulties were encountered when attempting to grow mosses and liverworts in an unshaded glasshouse, in spring and summer. Even spraying hourly with water did not prevent scorching and desiccation. Growth can be measured using a variety of techniques; height measurement and shoot elongation from thread markers proved the most reliabl

    Spectral universality of strong shocks accelerating charged particles

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    As a rule, the shock compression controls the spectrum of diffusively accelerated particles. We argue that this is not so if the backreaction of these particles on the shock structure is significant. We present a self-similar solution in which the accelerated particles change the flow structure near the shock so strongly that the total shock compression may become arbitrarily large. Despite this, the energy spectrum behind the shock is close to E^{-3/2} independently of anything at all.Comment: Submitted to ApJL, 4 pages, 1 figure, uses revtex and boxedep
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