2 research outputs found
Ensayo aleatorizado del cierre de orejuela izquierda vs varfarina para la prevención de accidentes cerebrovasculares tromboembólicos en pacientes con fibrilación auricular no relacionada con valvulopatía. Estudio PREVAIL
The successful application of poly(<i>N</i>-vinylcaprolactam)-based
microgels requires a profound understanding of their synthesis. For
this purpose, a validated process model for the microgels synthesis
by precipitation copolymerization with the cross-linker <i>N</i>,<i>N</i>′-methylenebis(acrylamide) is formulated.
Unknown reaction rate constants, reaction enthalpies, and partition
coefficients are obtained by quantum mechanical calculations. The
remaining parameter values are estimated from reaction calorimetry
and Raman spectroscopy measurements of experiments with different
monomer/cross-linker compositions. Because of high cross-propagation
reaction rate constants, simulations predict a fast incorporation
of the cross-linker. This agrees with reaction calorimetry measurements.
Furthermore, the gel phase is predicted as the major reaction locus.
The model is utilized for a prediction of the internal particle structure
regarding its cross-link distribution. The highly cross-linked core
reported in the literature corresponds to the predictions of the model
Automated Chemical Kinetic Modeling via Hybrid Reactive Molecular Dynamics and Quantum Chemistry Simulations
An automated scheme for obtaining
chemical kinetic models from
scratch using reactive molecular dynamics and quantum chemistry simulations
is presented. This methodology combines the phase space sampling of
reactive molecular dynamics with the thermochemistry and kinetics
prediction capabilities of quantum mechanics. This scheme provides
the NASA polynomial and modified Arrhenius equation parameters for
all species and reactions that are observed during the simulation
and supplies them in the ChemKin format. The ab initio level of theory
for predictions is easily exchangeable, and the presently used G3MP2
level of theory is found to reliably reproduce hydrogen and methane
oxidation thermochemistry and kinetics data. Chemical kinetic models
obtained with this approach are ready to use for, e.g., ignition delay
time simulations, as shown for hydrogen combustion. The presented
extension of the ChemTraYzer approach can be used as a basis for methodological
advancement of chemical kinetic modeling schemes and as a black-box
approach to generate chemical kinetic models