4,482 research outputs found

    Phase behaviour and dynamics in primitive models of molecular ionic liquids

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    The phase behaviour and dynamics of molecular ionic liquids are studied using primitive models and extensive computer simulations. The models account for size disparity between cation and anion, charge location on the cation, and cation-shape anisotropy, which are all prominent features of important materials such as room-temperature ionic liquids. The vapour-liquid phase diagrams are determined using high-precision Monte Carlo simulations, setting the scene for in-depth studies of ion dynamics in the liquid state. Molecular dynamics simulations are used to explore the structure, single-particle translational and rotational autocorrelation functions, cation orientational autocorrelations, self diffusion, viscosity, and frequency-dependent conductivity. The results reveal some of the molecular-scale mechanisms for charge transport, involving molecular translation, rotation, and association.Comment: 15 pages, 7 figure

    Application of NASTRAN/COSMIC in the analysis of ship structures to underwater explosion shock

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    The application of NASTRAN/COSMIC in predicting the transient motion of ship structures to underwater, non-contact explosions is discussed. Examples illustrate the finite element models, mathematical formulations of loading functions and, where available, comparisons between analytical and experimental results

    Study of arc-jet propulsion devices Final report, 20 Nov. 1964 - 19 Dec. 1965

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    Energy transfer mechanisms in radiation, water, and regeneratively cooled, and MPD arc jet propulsion device

    Traumatic pericardial rupture with skeletonized phrenic nerve

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    <p>Abstract</p> <p>Background</p> <p>Traumatic pericardial rupture is a rare presentation. Pericardial rupture itself is asymptomatic unless complicated by either hemorrhage or herniation of the heart through the defect. Following diagnosis surgical repair of the pericardium is indicated because cardiac herniation may result in vascular collapse and sudden death.</p> <p>Objectives</p> <p>Here we present a case of traumatic, non-herniated pericardial rupture with complete skeletonization of the phrenic nerve.</p> <p>Case report</p> <p>An 18-year-old healthy male suffered multi-trauma after falling 50 feet onto concrete. The patient could not be stabilized despite exploratory laparotomy with splenectomy, IR embolization and packing for a liver laceration. Right posterolateral thoracotomy revealed a ruptured pericardium with a completely skeletonized phrenic nerve. The pericardium was repaired with a Goretex(R) patch.</p> <p>Conclusion</p> <p>A high level of suspicion for pericardial rupture is necessary in all patients with high-velocity thoracic injuries.</p

    Renormalized couplings and scaling correction amplitudes in the N-vector spin models on the sc and the bcc lattices

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    For the classical N-vector model, with arbitrary N, we have computed through order \beta^{17} the high temperature expansions of the second field derivative of the susceptibility \chi_4(N,\beta) on the simple cubic and on the body centered cubic lattices. (The N-vector model is also known as the O(N) symmetric classical spin Heisenberg model or, in quantum field theory, as the lattice O(N) nonlinear sigma model.) By analyzing the expansion of \chi_4(N,\beta) on the two lattices, and by carefully allowing for the corrections to scaling, we obtain updated estimates of the critical parameters and more accurate tests of the hyperscaling relation d\nu(N) +\gamma(N) -2\Delta_4(N)=0 for a range of values of the spin dimensionality N, including N=0 [the self-avoiding walk model], N=1 [the Ising spin 1/2 model], N=2 [the XY model], N=3 [the classical Heisenberg model]. Using the recently extended series for the susceptibility and for the second correlation moment, we also compute the dimensionless renormalized four point coupling constants and some universal ratios of scaling correction amplitudes in fair agreement with recent renormalization group estimates.Comment: 23 pages, latex, no figure

    Maximumfactuur en kleine risico’s: verdeling van de eigen bijdragen voor gezondheidszorg in België

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    Overal in Europa komt de financiering van publieke systemen van ziekteverzekering of gezondheidszorg onder druk door de sterke stijging van de uitgaven. België ontsnapt niet aan deze evolutie. De stijging van de uitgaven voor gezondheidszorg lag bij ons zeker gedurende de laatste jaren zelfs duidelijk boven het Europese gemiddelde. Ondanks de grote maatschappelijke populariteit van ons systeem van verplichte ziekteverzekering, vormt het probleem van de kostenbeheersing toch steeds één van de belangrijkste discussiepunten tijdens de regeringsonderhandelingen. Wanneer de stijging van de uitgaven niet kan worden afgeremd, zullen in de toekomst ongetwijfeld fundamentele vragen over de organisatie van het systeem naar voor worden geschoven (Schokkaert en Van de Voorde, 2003)
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