9,348 research outputs found

    Motion synchronization of a mechanism to deploy and restow a truss beam

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    The functions of the Control of Flexible Structures I (COFS I) deployer and retractor assembly (DRA) are primarily to deploy and retract the Mast I beam, and secondarily to latch, unlatch, and restow the DRA mechanism. The problems associated with the diagonal folding mechanism that retracts the beam is presented, the synchronization requirements critical to the process of restowing the beam is discussed, and a proposed solution to the problem of synchronization between the mechanical systems is presented. In addition, a detailed description is presented of the design and functioning of the DRA

    Molded composite pyrogen igniter for rocket motors

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    A lightweight pyrogen igniter assembly including an elongated molded plastic tube adapted to contain a pyrogen charge was designed for insertion into a rocket motor casing for ignition of the rocket motor charge. A molded plastic closure cap provided for the elongated tube includes an ignition charge for igniting the pyrogen charge and an electrically actuated ignition squib for igniting the ignition charge. The ignition charge is contained within a portion of the closure cap, and it is retained therein by a noncorrosive ignition pellet retainer or screen which is adapted to rest on a shoulder of the elongated tube when the closure cap and tube are assembled together. A circumferentially disposed metal ring is provided along the external circumference of the closure cap and is molded or captured within the plastic cap in the molding process to provide, along with O-ring seals, a leakproof rotary joint

    A comparison of the chemistry of pseudotachylyte breccias in the Archean Levack Gneisses of the Sudbury structure, Ontario

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    The Archean Levack Gneisses of the North Range host millimeter-thick veins and centimeter-thick lenses of pseudotachylyte, as well as substantially larger meter-wide, dykelike bodies of pseudotachylytic 'breccia'. The 'breccia' occurs up to several tens of kilometers away from the Sudbury Igneous Complex and is commonly sited within or near joints and other natural weaknesses such as bedding, dyke contacts, and lithological boundaries. The larger 'breccia' dykes comprise a generally dark matrix containing rounded to subrounded and occasionally angular rock fragments derived predominantly from Levack Gneiss. Selected samples of bulk Sudbury Breccia and Sudbury Breccia matrices were chemically analyzed and compared to existing data on the Levack Gneisses and Sudbury Breccia. The matrices are apparently enriched in Fe and, to a lesser extent, Mg, Ti, and Ca compared to the wallrocks and the majority of clasts. This enrichment can be partly explained by the preferential cataclasis and/or frictional melting of hydrous ferromagnesian wallrock minerals, but also appear to require contamination by more basic exotic lithologies. This suggests that certain components of pseudotachylitic Sudbury Breccia have undergone significant transport during their formation

    Quaternary warping at Gorge Saddle, western Southland

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    Gorge Saddle is one low point on a drainage divide between Fiordland and the Southland Plain. Eastward sloping Quaternary terraces east of the divide and westward sloping terraces to the west contain granitic pebbles which could have been derived only from the west. This suggests doming at the present divide concurrent with transport from the west

    The precision of experienced action video-game players: Line bisection reveals reduced leftward response bias

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    Twenty-two experienced action video-game players (AVGPs) and 18 non-VGPs were tested on a pen-and-paper line bisection task that was untimed. Typically, right-handers bisect lines 2 % to the left of true centre, a bias thought to reflect the dominance of the right-hemisphere for visuospatial attention. Expertise may affect this bias, with expert musicians showing no bias in line bisection performance. Our results show that experienced-AVGPs also bisect lines with no bias with their right hand and a significantly reduced bias with their left hand compared to non-AVGPs. Bisections by experienced-AVGPs were also more precise than those of non-AVGPs. These findings show the cognitive proficiencies of experienced-AVGPs can generalize beyond computer based tasks, which resemble their training environment

    Just how expert are “expert” video-game players? Assessing the experience and expertise of video-game players across “action” video-game genres

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    Video-game play (particularly “action” video-games) holds exciting promise as an activity that may provide generalized enhancement to a wide range of perceptual and cognitive abilities (for review see Latham et al., 2013a). However, in this article we make the case that to assess accurately the effects of video-game play researchers must better characterize video-game experience and expertise. This requires a more precise and objective assessment of an individual's video-game history and skill level, and making finer distinctions between video-games that fall under the umbrella of “action” games. Failure to consider these factors may partly be responsible for mixed findings (see Boot et al., 2011)
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