64,947 research outputs found

    Investigation of Techniques for Simulating Communications and Tracking Subsystems on Space Station Freedom

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    The need to reduce the costs of Space Station Freedom has resulted in a major redesign and downsizing of the Station in general, and its Communications and Tracking (C&T) components in particular. Earlier models and simulations of the C&T Space-to-Ground Subsystem (SGS) in particular are no longer valid. There thus exists a general need for updated, high fidelity simulations of C&T subsystems. This project explored simulation techniques and methods that might be used in developing new simulations of C&T subsystems, including the SGS. Three requirements were placed on the simulations to be developed: (1) they run on IBM PC/XT/AT compatible computers; (2) they be written in Ada as much as possible; and (3) since control and monitoring of the C&T subsystems will involve communication via a MIL-STD-1553B serial bus, that the possibility of commanding the simulator and monitoring its sensors via that bus be included in the design of the simulator. The result of the project is a prototype of a simulation of the Assembly/Contingency Transponder of the SGS, written in Ada, which can be controlled from another PC via a MIL-STD-1553B bus

    Etymology of the earwigfly, Merope tuber Newman (Mecoptera: Meropeidae): Simply dull or just inscrutable?

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    The naturalist Edward Newman did not provide an etymology for the mecopteran Merope tuber when he described it in 1838. In 1872 Asa Fitch asserted that the genus was named after Merope one of the Pleiades sisters of Greek mythology; however, he provided no reason for his assumption. We researched several etymological alternatives. We concur with Fitch and conclude that Newman did indeed name the genus Merope after the dullest of the Pleiades sisters

    A state record for the Oconee scorpionfly, Panorpa oconee Byers (Mecoptera: Panorpidae), in Florida

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    I provide the first state record for the Oconee scorpionfly, Panorpa oconee Byers, from Putnam County, Florida. This is the southernmost record for P. oconee, extends its range 321 km south of its known distribution and, if valid, adds a seventh described species of panorpid, and twelfth mecopteran, indigenous to Florida

    Rediscovering the West: An Inquiry into Nothingness and Relatedness: A Review

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    Storing carbon in soil. Can we slow a revolving door?

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    There is no doubt that soils are a vast store of carbon and partially control the carbon dioxide content of the atmosphere. Maintaining soil organic matter is also crucial for production and environmental protection. Land-use change and management practices are central to maintaining soil carbon, because these can both increase and decrease soil carbon. Pasture systems can store large amounts of soil carbon and there may be an opportunity to store more in New Zealand dairy systems with multiple benefits. Active research is investigating approaches to achieve this goal through the New Zealand Agricultural Greenhouse Gas Research Centre

    Computational modeling and validation for hypersonic inlets

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    Hypersonic inlet research activity at NASA is reviewed. The basis is the experimental tests performed with three inlets: the NASA Lewis Research Center Mach 5, the McDonnell Douglas Mach 12, and the NASA Langley Mach 18. Both three-dimensional parabolized Navier-Stokes and Navier-Stokes codes were used to compute the flow within the three inlets. Modeling assumptions in the codes involve the turbulence model, the nature of the boundary layer, shock wave boundary layer interaction, and the flow spilled to the outside of the inlet. Use of the codes in conjunction with the experimental data are helping to develop a clearer understanding of the inlet flow physics and to focus on the modeling improvements required in order to arrive at validated codes

    Final Report

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    The discussion of simulators and simulation, data aquisition and transmission and evaluation of Ada compilers and programming environments is presented. The following subject areas are covered: Bus 1553B software development; simulator development; and Ada programs to interface with C-software which drives PC-based interface cards for 1553B bus
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