27,342 research outputs found

    Multiple pass reimaging optical system

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    An optical imaging system for enabling nonabsorbed light imaged onto a photodetective surface to be collected and reimaged one or more times onto that surface in register with the original image. The system includes an objective lens, one or more imaging lenses, one or more retroreflectors and perhaps a prism for providing optical matching of the imaging lens focal planes to the photo detective surface

    Extension and application of a sequential estimator

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    Improved sequential estimation technique for nonlinear time varying system

    Development of Replacement Heifers using Combinations of Three Forage Types and Feed Supplements (with or without Broiler Litter)

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    The proper management of replacement heifers is an essential component of successful cow/calf operations. The level of management and nutrition applied to replacement heifers as calves and yearlings can impact their subsequent reproductive performance and productivity

    Analytical study of a free-wing/free-trimmer concept

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    The free-wing/free-trimmer is a NASA-Conceived extension of the free-wing concept intended to permit the use of high-lift flaps. Wing pitching moments are balanced by a smaller, external surface attached by a boom or equivalent structure. The external trimmer is, itself, a miniature free wing, and pitch control of the wing-trimmer assembly is effected through a trailing-edge control tab on the trimmer surface. The longitudinal behavior of representative small free-wing/free-trimmer aircraft was analyzed. Aft-mounted trimmer surfaces are found to be superior to forward trimmers, although the permissible trimmer moment arm is limited, in both cases, by adverse dynamic effects. Aft-trimmer configurations provide excellent gust alleviation and meet fundamental stick-fixed stability criteria while exceeding the lift capabilities of pure free-wing configurations

    Analysis of the linearity characteristics, tape recorders and compensation effects in the FM/FM telemetry system

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    Linearity characteristics, tape recorder effects, and tape speed compensation effects in FM/FM TELEMETRY syste

    Semiclassical charged black holes with a quantized massive scalar field

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    Semiclassical perturbations to the Reissner-Nordstrom metric caused by the presence of a quantized massive scalar field with arbitrary curvature coupling are found to first order in \epsilon = \hbar/M^2. The DeWitt-Schwinger approximation is used to determine the vacuum stress-energy tensor of the massive scalar field. When the semiclassical perturbation are taken into account, we find extreme black holes will have a charge-to-mass ratio that exceeds unity, as measured at infinity. The effects of the perturbations on the black hole temperature (surface gravity) are studied in detail, with particular emphasis on near extreme ``bare'' states that might become precisely zero temperature ``dressed'' semiclassical black hole states. We find that for minimally or conformally coupled scalar fields there are no zero temperature solutions among the perturbed black holes.Comment: 19 pages; 1 figure; ReVTe

    Atomic and Molecular Opacities for Brown Dwarf and Giant Planet Atmospheres

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    We present a comprehensive description of the theory and practice of opacity calculations from the infrared to the ultraviolet needed to generate models of the atmospheres of brown dwarfs and extrasolar giant planets. Methods for using existing line lists and spectroscopic databases in disparate formats are presented and plots of the resulting absorptive opacities versus wavelength for the most important molecules and atoms at representative temperature/pressure points are provided. Electronic, ro-vibrational, bound-free, bound-bound, free-free, and collision-induced transitions and monochromatic opacities are derived, discussed, and analyzed. The species addressed include the alkali metals, iron, heavy metal oxides, metal hydrides, H2H_2, H2OH_2O, CH4CH_4, COCO, NH3NH_3, H2SH_2S, PH3PH_3, and representative grains. [Abridged]Comment: 28 pages of text, plus 22 figures, accepted to the Astrophysical Journal Supplement Series, replaced with more compact emulateapj versio

    Cosmological Supergravity from a Massive Superparticle and Super Cosmological Black Holes

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    We describe in superspace a classical theory of two dimensional (1,1)(1,1) dilaton supergravity with a cosmological constant, both with and without coupling to a massive superparticle. We give general exact non-trivial superspace solutions for the compensator superfield that describes the supergravity in both cases. We then use these compensator solutions to construct models of two-dimensional supersymmetric cosmological black holes.Comment: 20 pages, Late
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