4,482 research outputs found
Phase behaviour and dynamics in primitive models of molecular ionic liquids
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
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
Energy transfer mechanisms in radiation, water, and regeneratively cooled, and MPD arc jet propulsion device
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Tracking and Analysis Framework (TAF) model documentation and user`s guide
With passage of the 1990 Clean Air Act Amendments, the United States embarked on a policy for controlling acid deposition that has been estimated to cost at least $2 billion. Title IV of the Act created a major innovation in environmental regulation by introducing market-based incentives - specifically, by allowing electric utility companies to trade allowances to emit sulfur dioxide (SO{sub 2}). The National Acid Precipitation Assessment Program (NAPAP) has been tasked by Congress to assess what Senator Moynihan has termed this {open_quotes}grand experiment.{close_quotes} Such a comprehensive assessment of the economic and environmental effects of this legislation has been a major challenge. To help NAPAP face this challenge, the U.S. Department of Energy (DOE) has sponsored development of an integrated assessment model, known as the Tracking and Analysis Framework (TAF). This section summarizes TAF`s objectives and its overall design
Traumatic pericardial rupture with skeletonized phrenic nerve
<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
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
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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