3,894 research outputs found

    Energy management of three-dimensional minimum-time intercept

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    A real-time computer algorithm to control and optimize aircraft flight profiles is described and applied to a three-dimensional minimum-time intercept mission

    An on-board near-optimal climb-dash energy management

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    On-board real time flight control is studied in order to develop algorithms which are simple enough to be used in practice, for a variety of missions involving three dimensional flight. The intercept mission in symmetric flight is emphasized. Extensive computation is required on the ground prior to the mission but the ensuing on-board exploitation is extremely simple. The scheme takes advantage of the boundary layer structure common in singular perturbations, arising with the multiple time scales appropriate to aircraft dynamics. Energy modelling of aircraft is used as the starting point for the analysis. In the symmetric case, a nominal path is generated which fairs into the dash or cruise state. Feedback coefficients are found as functions of the remaining energy to go (dash energy less current energy) along the nominal path

    Measurement of the B_s^0→K^+K^- lifetime relative to the B_d^0→K^+π^- lifetime

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    The study of B decays to charmless charged hadrons offers an opportunity to improve our understanding CP violation and to search for New Physics beyond the Standard Model. We present an analysis to make a measurement of the B_s^0→K^+K^- lifetime relative to B_d^0 lifetime which removes systematic bias introduced to the lifetime by distance of flight based selections

    Climb-dash real-time calculations

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    On-board rear-optimal climb-dash energy management, optimal symmetric flight with an intermediate vehicle model, and energy states are presented

    Spin Seebeck effect from antiferromagnetic magnons and critical spin fluctuations in epitaxial FeF2 films

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    We report a longitudinal spin Seebeck effect (SSE) study in epitaxially grown FeF2(110) antiferromagnetic (AFM) thin films with strong uniaxial anisotropy over the temperature range of 3.8 - 250 K. Both the magnetic field- and temperature-dependent SSE signals below the N\'eel temperature (TN=70 K) of the FeF2 films are consistent with a theoretical model based on the excitations of AFM magnons without any net induced static magnetic moment. In addition to the characteristic low-temperature SSE peak associated with the AFM magnons, there is another SSE peak at TN which extends well into the paramagnetic phase. All the SSE data taken at different magnetic fields up to 12 T near and above the critical point TN follow the critical scaling law very well with the critical exponents for magnetic susceptibility of 3D Ising systems, which suggests that the AFM spin correlation is responsible for the observed SSE near TN

    You\u27d Better Get A Girl Before The Boys Come Home Or You\u27ll Never Get A Girl At All

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    https://digitalcommons.library.umaine.edu/mmb-vp/3459/thumbnail.jp
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