4,066 research outputs found

    Phase behavior of repulsive polymer-tethered colloids

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    We report molecular dynamics simulations of a system of repulsive, polymer-tethered colloidal particles. We use an explicit polymer model to explore how the length and the behavior of the polymer (ideal or self-avoiding) affect the ability of the particles to organize into ordered structures when the system is compressed to moderate volume fractions. We find a variety of different phases whose origin can be explained in terms of the configurational entropy of polymers and colloids. Finally, we discuss and compare our results to those obtained for similar systems using simplified coarse-grained polymer models, and set the limits of their applicability.Comment: 7 pages, 5 figures. Published in the Journal of Chemical Physic

    Rotational arherectomy in the distal left anterior descending coronary artery through an internal mammary artery graft.

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    We report the case of a 53-year-old white man who began complaining of dyspnoea and angina 19 months after coronary artery bypass graft surgery. Coronary angiography revealed the presence of a long and critical stenosis in the native left anterior descending coronary artery, shortly after distal anastomosis of the left internal mammary artery. After failed predilatations with standard or cutting balloons, we successfully used the rotablator system, which allowed us to implant a bare-metal stent in the native left anterior descending coronary artery. However, stent deployment caused long linear graft dissection, which was reduced by drug-eluting stent implantation in the proximal and distal segments of the left internal mammary artery

    Control of a charging station for electric vehicles

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    A weighted average current control applied to a three-phase inductor-capacitor-inductor grid-connected battery charger for electric vehicles is presented in this paper. The proposed controller is based on a combination of the partial currents of the system (inverter and grid currents), which are feedback into the control loop. Therefore, by using this approach a reduction of the system order is achieved. The proposed controller allows a bidirectional control of the converter currents, thus allowing both, a controlled charge of the battery and the injection of the current with low distortion in the grid. Further, the implemented controller does not needs to measure the inverter currents. The control strategy is validated with simulation results. © Published under licence by IOP Publishing Ltd

    On the evaluation of photogrammetric methods for dense 3D surface reconstruction in a metrological context.

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    This paper discusses a methodology to evaluate the accuracy of recently developed image-based 3D modelling techniques. So far, the emergence of these novel methods has not been supported by the definition of an internationally recognized standard which is fundamental for user confidence and market growth. In order to provide an element of reflection and solution to the different communities involved in 3D imaging, a promising approach is presented in this paper for the assessment of both metric quality and limitations of an open-source suite of tools (Apero/MicMac), developed for the extraction of dense 3D point clouds from a set of un- ordered 2D images. The proposed procedural workflow is performed within a metrological context, through inter-comparisons with \u2018reference\u2019 data acquired with two hemispherical laser scanners, one total station, and one laser tracker. The methodology is applied to two case studies, designed in order to analyse the software performances in dealing with both outdoor and environmentally controlled conditions, i.e. the main entrance of Cath\ue9drale de la Major (Marseille, France) and a custom-made scene located at National Research Council of Canada 3D imaging Metrology Laboratory (Ottawa). Comparative data and accuracy evidence produced for both tests allow the study of some key factors affecting 3D model accuracy

    Imitation in Large Games

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    In games with a large number of players where players may have overlapping objectives, the analysis of stable outcomes typically depends on player types. A special case is when a large part of the player population consists of imitation types: that of players who imitate choice of other (optimizing) types. Game theorists typically study the evolution of such games in dynamical systems with imitation rules. In the setting of games of infinite duration on finite graphs with preference orderings on outcomes for player types, we explore the possibility of imitation as a viable strategy. In our setup, the optimising players play bounded memory strategies and the imitators play according to specifications given by automata. We present algorithmic results on the eventual survival of types
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