5,033 research outputs found

    Definition of technology development missions for early space stations: Large space structures

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    The objectives studied are the definition of the tested role of an early Space Station for the construction of large space structures. This is accomplished by defining the LSS technology development missions (TDMs) identified in phase 1. Design and operations trade studies are used to identify the best structural concepts and procedures for each TDMs. Details of the TDM designs are then developed along with their operational requirements. Space Station resources required for each mission, both human and physical, are identified. The costs and development schedules for the TDMs provide an indication of the programs needed to develop these missions

    Spring Regrowth and Steer Performance on Tifton 85 and Coastal Bermudagrass Pastures Following Sod-Seeding with Ryegrass

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    Effects of autumn sod-seeded ryegrass (Lolium multiflorum; cv. Passerel; 37.7 kg/ha) in bermudagrass pastures (Cynodon spp.; cv. Coastal and cv. Tifton 85) on grazing steer performance were determined. Ryegrass was sod-seeded in three of six .81 ha pastures of each bermudagrass. Forage height was adjusted to10 cm during spring. Stocking rates were unaffected by ryegrass in Tifton 85 pastures, but they were higher (P \u3c .05) for Tifton 85 than Coastal. Ryegrass increased tester steer average daily gains by 34% (.86 vs .64 kg/day; P \u3c .01), and gain/ha by 26% (387 vs 306 kg/ha; P \u3c .05). Higher stocking rates resulted in 22% more grazing days (515 vs 421 days/ha; P \u3c .01), and 30% higher gain/ha (391 vs 301 kg/ha; P \u3c .05) for Tifton 85 than Coastal pastures. Ryegrass did not affect stocking rates or steer performance on Tifton 85, but it depressed both on Coastal pastures

    Electrochemical deposition of silver crystals aboard Skylab 4

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    Silver crystals were grown aboard Skylab 4 by an electro-chemical reaction and subsequently returned to earth for comparison with crystals grown at 1- and 5-g. Both the Skylab and earth-grown crystals show a variety of structures. Certain tendencies in structure dependency on gravity level, however, can be discerned. In addition, downward growing dendrite streamers; upward growing chunky crystal streamers; growth along an air/liquid interface; and ribbon, film, and fiber crystal habits were observed in experiments conducted on the ground with solutions of varying concentrations. It was also observed that the crystal structures of space and ground electro-deposited silver crystals were very similar to the structures of germanium selenide and germanium telluride crystals grown in space and on the ground by a vapor transport technique. Consideration of the data leads to the conclusions that: (1) the rate of electrochemical displacement of silver ions from a 5 percent aqueous solution by copper is predominantly diffussion controlled in space and kinetically controlled in 1- and higher-g because of augmentation of mass transport by convection; (2) downward and upward crystal streamers are the result of gravity-driven convection, the flow patterns of which can be delineated. Lateral growths along an air/liquid interface are the result of surface-tension-driven convection, the pattern of which also can be delineated; (3) electrolysis in space or low-g environments can produce either dendritic crystals with more perfect microcrystalline structures or massive, single crystals with fewer defects than those grown on ground or at higher g-levels. Ribbons or films of space-grown silicon crystals would find a ready market for electronic substrate and photocell applications. Space-grown dendritic, metal crystals present the possibility of unique catalysts. Large perfect crystals of various materials are desired for a number of electronic and optical applications; and (4) vapor transport growth of germanium selenide and germanium telluride is affected by convection mechanisms similar to the mechanisms hypothesized for the electrochemical deposition of silver crystals. Evidence and considerations leading to the preceding summaries and conclusions are presented. The implications of the findings and conclusions for technological applications are discussed, and recommendations for further experiments are presented

    Electronic Controls for Swine Buildings

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    This fact sheet discusses the use of electronic controllers to maintain the environment within swine barns. There are some special considerations when using electronic controllers to replace traditional control systems. Three main items are addressed in this fact sheet: 1) the selection of a controller, 2) installation considerations, and 3) protection against controller failure

    Effective Symmetries of the Minimal Supermultiplet of N = 8 Extended Worldline Supersymmetry

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    A minimal representation of the N = 8 extended worldline supersymmetry, known as the `ultra-multiplet', is closely related to a family of supermultiplets with the same, E(8) chromotopology. We catalogue their effective symmetries and find a Spin(4) x Z(2) subgroup common to them all, which explains the particular basis used in the original construction. We specify a constrained superfield representation of the supermultiplets in the ultra-multiplet family, and show that such a superfield representation in fact exists for all adinkraic supermultiplets. We also exhibit the correspondences between these supermultiplets, their Adinkras and the E(8) root lattice bases. Finally, we construct quadratic Lagrangians that provide the standard kinetic terms and afford a mixing of an even number of such supermultiplets controlled by a coupling to an external 2-form of fluxes.Comment: 13 Figure

    Computer generated animation and movie production at LARC: A case study

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    The process of producing computer generated 16mm movies using the MOVIE.BYU software package developed by Brigham Young University and the currently available hardware technology at the Langley Research Center is described. A general overview relates the procedures to a specific application. Details are provided which describe the data used, preparation of a storyboard, key frame generation, the actual animation, title generation, filming, and processing/developing the final product. Problems encountered in each of these areas are identified. Both hardware and software problems are discussed along with proposed solutions and recommendations

    SMP: A solid modeling program version 2.0

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    The Solid Modeling Program (SMP) provides the capability to model complex solid objects through the composition of primitive geometric entities. In addition to the construction of solid models, SMP has extensive facilities for model editing, display, and analysis. The geometric model produced by the software system can be output in a format compatible with existing analysis programs such as PATRAN-G. The present version of the SMP software supports six primitives: boxes, cones, spheres, paraboloids, tori, and trusses. The details for creating each of the major primitive types is presented. The analysis capabilities of SMP, including interfaces to existing analysis programs, are discussed

    Codes and Supersymmetry in One Dimension

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    Adinkras are diagrams that describe many useful supermultiplets in D=1 dimensions. We show that the topology of the Adinkra is uniquely determined by a doubly even code. Conversely, every doubly even code produces a possible topology of an Adinkra. A computation of doubly even codes results in an enumeration of these Adinkra topologies up to N=28, and for minimal supermultiplets, up to N=32.Comment: 48 pages, a new version that combines arXiv:0811.3410 and parts of arXiv:0806.0050, for submission for publicatio
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