27,034 research outputs found

    Sexual conflict

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    Modeling aerodynamic discontinuities and the onset of chaos in flight dynamical systems

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    Various representations of the aerodynamic contribution to the aircraft's equation of motion are shown to be compatible within the common assumption of their Frechet differentiability. Three forms of invalidating Frechet differentiality are identified, and the mathematical model is amended to accommodate their occurrence. Some of the ways in which chaotic behavior may emerge are discussed, first at the level of the aerodynamic contribution to the equation of motion, and then at the level of the equations of motion themselves

    Sequence distribution studies of dichloroprotoanemonin-methyl methacrylate copolymers

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    Chloride elimination and ultraviolet bands in dichloroprotoanemonin/methyl methacrylate copolymer

    Comparison of toughened composite laminates using NASA standard damage tolerance tests

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    The proposed application of composite materials to transport wing and fuselage structures prompted the search for tougher materials having improved resistance to impact damage and delamination. Several resin/graphite fiber composite materials were subjected to standard damage tolerance tests and the results were compared to ascertain which materials have superior toughness. In addition, test results from various company and NASA laboratories were compared for repeatability

    One-degree-of-freedom motion induced by modeled vortex shedding

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    The motion of an elastically supported cylinder forced by a nonlinear, quasi-static, aerodynamic model with the unusual feature of a motion-dependent forcing frequency was studied. Numerical solutions for the motion and the Lyapunov exponents are presented for three forcing amplitudes and two frequencies (1.0 and 1.1 times the Strouhal frequency). Initially, positive Lyapunov exponents occur and the motion can appear chaotic. After thousands of characteristic times, the motion changes to a motion (verified analytically) that is periodic and damped. This periodic, damped motion was not observed experimentally, thus raising questions concerning the modeling

    Analytical and experimental investigations of low level acceleration measurement techniques

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    Construction techniques for accelerometer with low level threshold sensitivit
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