376 research outputs found

    Chromatically corrected virtual image visual display

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    An in-line, three element, large diameter, optical display lens is disclosed which has a front convex-convex element, a central convex-concave element, and a rear convex-convex element. The lens, used in flight simulators, magnifies an image presented on a television monitor and, by causing light rays leaving the lens to be in essentially parallel paths, reduces eye strain of the simulator operator

    Description and performance of the Langley differential maneuvering simulator

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    The differential maneuvering simulator for simulating two aircraft or spacecraft operating in a differential mode is described. Tests made to verify that the system could provide the required simulated aircraft motions are given. The mathematical model which converts computed aircraft motions into the required motions of the various projector gimbals is described

    High-speed real-time animated displays on the ADAGE (trademark) RDS 3000 raster graphics system

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    Techniques which may be used to increase the animation update rate of real-time computer raster graphic displays are discussed. They were developed on the ADAGE RDS 3000 graphic system in support of the Advanced Concepts Simulator at the NASA Langley Research Center. These techniques involve the use of a special purpose parallel processor, for high-speed character generation. The description of the parallel processor includes the Barrel Shifter which is part of the hardware and is the key to the high-speed character rendition. The final result of this total effort was a fourfold increase in the update rate of an existing primary flight display from 4 to 16 frames per second

    A granular briquet resistance furnace for the electrothermic dry distillation of zinc ores

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    The work here described had for its purpose the development of a granular briquet resistance furnace for the electrothermic dry distillation of zinc ores --Introduction, page 1

    Analysis and design of a refractive virtual image system

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    The optical performance of a virtual image display system is evaluated. Observation of a two-element (unachromatized doublet) refractive system led to the conclusion that the major source of image degradation was lateral chromatic aberration. This conclusion was verified by computer analysis of the system. The lateral chromatic aberration is given in terms of the resolution of the phosphor dots on a standard shadow mask color cathode ray tube. Single wavelength considerations include: astigmatism, apparent image distance from the observer, binocular disparities and differences of angular magnification of the images presented to each of the observer's eyes. Where practical, these results are related to the performance of the human eye. All these techniques are applied to the previously mentioned doublet and a triplet refractive system. The triplet provides a 50-percent reduction in lateral chromatic aberration which was the design goal. Distortion was also reduced to a minimum over the field of view. The methods used in the design of the triplet are presented along with a method of relating classical aberration curves to image distance and binocular disparity

    Spatial-frequency response of the limb infrared monitor of the stratosphere

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    Measurements from the Limb Infrared Monitor of the stratosphere (LIMS) are presented and discussed. From the LIMS design model data, the modulation transfer function (MTF) was calculated for the optical system, the detector field mask, the electronics, and the overall system for each channel. The signal output performance of the instrument was predicted from the system MTF data and model input radiance data for each channel. The MTF measurements made on the flight sensor confirmed the analytical results

    Simulation of a passive millimeter wave sensor

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    The visual display expected to be generated by a Passive Millimeter Wave (PMMW) camera and sensor system has been simulated on a Silicon Graphics IRIS workstation at the NASA Langley Research Center (LaRC). The low resolution of the sensor has been simulated by graphically manipulating the scene as it is being drawn by the IRIS in real time. Camera field of view, sensor resolution, and sensor update rate are the controllable parameters. Physical effects such as lens model, radome effects, and noise have not been included at this time. An approximate dynamic model of the atmospheric phenomenology has been included which generates the gray-scale intensity values in real time for the simulated image. The gray-scale values are proportional to temperature. A snapshot capability which captures individual image frames during real-time operation has been included. These images were used to validate the approximate phenomenology model against a more rigorous physical model

    The reduced distribution functions for charged particles with many-body interactions

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    We consider a multi-component system of charged particles that interact via a general many-body potential, and calculate the reduced distribution functions from the Bogoliubov-Born-Green-Kirkwood-Yvon hierarchy of equations in the form of a screened virial expansion through second orderМи розглядаємо багатокомпонентну систему заряджених частинок, які взаємодіють через загальний багаточастинковий потенціал, і обчислюємо функції розподілу з ієрархії рівнянь Боголюбова-Борна-Ґріна-Кірквуда-Івона у формі екранованого віріального розкладу до другого порядку включно

    A Semi-relativistic Equation of State for Stellar Interiors

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    Using the technique of Pade Approximants for the correlation contributions of charged particles we are able to reproduce complex mathematical expressions by simple algebraic formulas. The Pade formulas are analytical expressions, which interpolate between certain density-temperature regions and are characterized by exact asymptotics. We present a semi-relativistic description of the thermodynamics applicable for stellar interiors. Comparisons with equation-of-state data obtained by other calculational schemes are presented.Comment: 4 pages including 2 PostScript figures, also available from http://www.speckle.mpifr-bonn.mpg.de/publications.html, accepted for publication in Contributions to Plasma Physic