108 research outputs found

    The True Power of the MEMESat-1 CubeSat: Using FreeFlyer to Develop Advanced Power Simulations

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    The University of Georgia\u27s Small Satellite Research Lab\u27s Mission for Education and Multimedia Engagement Satellite (MEMESat-1) requires the use of variables such as power generation, power draw, orbital path, packet size, and data processing times. As power generation and change varies, MEMESat-1 will automatically transition through three operational modes to prevent battery depletion and halt system processes in case of anomalies. Taking these variables and operational modes into account, the MEMESat-1 Mission Operations (MOPS) team will use FreeFlyer software to create a power simulation model useful for analyzing power generation and draw during MEMESat-1\u27s orbital cycle. The power limitations of MEMESat-1 are budgeted based on battery and solar cell specifications implying the necessity of power simulations by MOPS

    2017 update of the WSES guidelines for emergency repair of complicated abdominal wall hernias

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    Emergency repair of complicated abdominal wall hernias may be associated with worsen outcome and a significant rate of postoperative complications. There is no consensus on management of complicated abdominal hernias. The main matter of debate is about the use of mesh in case of intestinal resection and the type of mesh to be used. Wound infection is the most common complication encountered and represents an immense burden especially in the presence of a mesh. The recurrence rate is an important topic that influences the final outcome. A World Society of Emergency Surgery (WSES) Consensus Conference was held in Bergamo in July 2013 with the aim to define recommendations for emergency repair of abdominal wall hernias in adults. This document represents the executive summary of the consensus conference approved by a WSES expert panel. In 2016, the guidelines have been revised and updated according to the most recent available literature.Peer reviewe

    On the mechanisms governing gas penetration into a tokamak plasma during a massive gas injection

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    A new 1D radial fluid code, IMAGINE, is used to simulate the penetration of gas into a tokamak plasma during a massive gas injection (MGI). The main result is that the gas is in general strongly braked as it reaches the plasma, due to mechanisms related to charge exchange and (to a smaller extent) recombination. As a result, only a fraction of the gas penetrates into the plasma. Also, a shock wave is created in the gas which propagates away from the plasma, braking and compressing the incoming gas. Simulation results are quantitatively consistent, at least in terms of orders of magnitude, with experimental data for a D 2 MGI into a JET Ohmic plasma. Simulations of MGI into the background plasma surrounding a runaway electron beam show that if the background electron density is too high, the gas may not penetrate, suggesting a possible explanation for the recent results of Reux et al in JET (2015 Nucl. Fusion 55 093013)

    Overview of the JET ITER-like wall divertor

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    Power exhaust by SOL and pedestal radiation at ASDEX Upgrade and JET

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    ELM divertor peak energy fluence scaling to ITER with data from JET, MAST and ASDEX upgrade

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    Multi-machine scaling of the main SOL parallel heat flux width in tokamak limiter plasmas

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    Assessment of erosion, deposition and fuel retention in the JET-ILW divertor from ion beam analysis data

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    2017 update of the WSES guidelines for emergency repair of complicated abdominal wall hernias

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    Progress in understanding disruptions triggered by massive gas injection via 3D non-linear MHD modelling with JOREK

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    3D non-linear MHD simulations of a D 2 massive gas injection (MGI) triggered disruption in JET with the JOREK code provide results which are qualitatively consistent with experimental observations and shed light on the physics at play. In particular, it is observed that the gas destabilizes a large m/n = 2/1 tearing mode, with the island O-point coinciding with the gas deposition region, by enhancing the plasma resistivity via cooling. When the 2/1 island gets so large that its inner side reaches the q = 3/2 surface, a 3/2 tearing mode grows. Simulations suggest that this is due to a steepening of the current profile right inside q = 3/2. Magnetic field stochastization over a large fraction of the minor radius as well as the growth of higher n modes ensue rapidly, leading to the thermal quench (TQ). The role of the 1/1 internal kink mode is discussed. An I p spike at the TQ is obtained in the simulations but with a smaller amplitude than in the experiment. Possible reasons are discussed
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