12,403 research outputs found

    Latching mechanism Patent

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    Latch for fastening spacecraft docking ring

    Nonlinearity and pixel shifting effects in HXRG infrared detectors

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    We study the nonlinearity (NL) in the conversion from charge to voltage in infrared detectors (HXRG) for use in precision astronomy. We present laboratory measurements of the NL function of a H2RG detector and discuss the accuracy to which it would need to be calibrated in future space missions to perform cosmological measurements through the weak gravitational lensing technique. In addition, we present an analysis of archival data from the infrared H1RG detector of the Wide Field Camera 3 in the Hubble Space Telescope that provides evidence consistent with the existence of a sensor effect analogous to the brighter-fatter effect found in Charge-Coupled Devices. We propose a model in which this effect could be understood as shifts in the effective pixel boundaries, and discuss prospects of laboratory measurements to fully characterize this effect.Comment: Accepted for publication in the Journal of Instrumentation (JINST). Part of "Precision Astronomy with Fully Depleted CCDs" (Dec 1-2, 2016), Brookhaven National Laboratory, Upton, NY, US

    Underperforming policy networks : the biopesticides network in the United Kingdom

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    Loosely integrated and incomplete policy networks have been neglected in the literature. They are important to consider in terms of understanding network underperformance. The effective delivery and formulation of policy requires networks that are not incomplete or underperforming. The biopesticides policy network in the United Kingdom is considered and its components identified with an emphasis on the lack of integration of retailers and environmental groups. The nature of the network constrains the actions of its agents and frustrates the achievement of policy goals. A study of this relatively immature policy network also allows for a focus on network formation. The state, via an external central government department, has been a key factor in the development of the network. Therefore, it is important to incorporate such factors more systematically into understandings of network formation. Feedback efforts from policy have increased interactions between productionist actors but the sphere of consumption remains insufficiently articulated

    Correlation study of finite element analysis

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    A study was conducted to investigate and prove the correlation between the NASTRAN predicted stresses and those measured on an actual structure. NASTRAN is a general purpose digital computer program for the analysis of large complex structures. A real airframe, which had logged several thousand hours flying time, was obtained, instrumented, and loaded to obtain the measured strains
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