Search results for "Monte carlo method"
showing 10 items of 1234 documents
Peptide Metal–Organic Frameworks for Enantioselective Separation of Chiral Drugs
2017
We report the ability of a chiral Cu(II) 3D MOF based on the tripeptide Gly-L-His-Gly (GHG) for the enantioselective separation of metamphetamine and ephedrine. Monte Carlo simulations suggest that chiral recognition is linked to preferential binding of one of the enantiomers as result of either stronger or additional H-bonds with the framework that lead to energetically more stable diastereomeric adducts. Solid phase extraction (SPE) of a racemic mixture by using Cu(GHG) as extractive phase permits isolating more than 50% of the (+)-ephedrine enantiomer as target compound in only four minutes. To the best of our knowledge, this represents the first example of a MOF capable of separating ch…
Analysis of transverse momentum correlations in hadronic Z decays
1999
In a recent paper, evidence was presented for a significant, positive correlation between the total transverse momenta of particles on opposite hemispheres of hadronic events. A new, model independent analysis of the data has been made. Two components can be distinguished in the correlation, and quantitative estimates of each are given. The results form a significant test of Monte Carlo models and some of the physics behind them. (C) 1999 Published by Elsevier Science B.V. All rights reserved.
Classical and Quantum Two-Dimensional Fluids in the Gibbs Ensemble
1994
We study the properties of model fluids in two spatial dimensions with Gibbs ensemble Monte Carlo (GEMC) techniques. In particular in the first part of the paper we study the entropy driven phase separation in case of a nonadditive symmetric hard disc fluid and locate by a combination of GEMC with finite size scaling techniques the critical line of nonadditivities as a function of the system density, which separates the mixing/demixing regions, we compare with a simple approximation. In the second part we successfully combine path integral Monte Carlo (PIMC) and GEMC techniques in order to locate the gas-liquid coexistence densities for a fluid with classical degrees of freedom and internal…
Do the contact angle and line tension of surface-attached droplets depend on the radius of curvature?
2018
Results from Monte Carlo simulations of wall-attached droplets in the three-dimensional Ising lattice gas model and in a symmetric binary Lennard-Jones fluid, confined by antisymmetric walls, are analyzed, with the aim to estimate the dependence of the contact angle $(\Theta)$ on the droplet radius $(R)$ of curvature. Sphere-cap shape of the wall-attached droplets is assumed throughout. An approach, based purely on "thermodynamic" observables, e.g., chemical potential, excess density due to the droplet, etc., is used, to avoid ambiguities in the decision which particles belong (or do not belong, respectively) to the droplet. It is found that the results are compatible with a variation $[\Th…
Monte Carlo Study of Critical Point Shifts in Thin Films
2000
We report preliminary results of Monte Carlo simulations of critical point shifts in thin slit-like capillaries. By making use of the isomorphism with an Ising model subject to bulk and surface fields and employing a multi-cluster update algorithm with ghost-spin term we obtain the coexistence curve and the behavior at the critical point for various film thicknesses D.
Replica-exchange molecular dynamics simulation for supercooled liquids
2000
We investigate to what extend the replica-exchange Monte Carlo method is able to equilibrate a simple liquid in its supercooled state. We find that this method does indeed allow to generate accurately the canonical distribution function even at low temperatures and that its efficiency is about 10-100 times higher than the usual canonical molecular dynamics simulation.
Design and Performance of a Lead Fluoride Detector as a Luminosity Monitor
2016
Nuclear instruments & methods in physics research / A 826, 6 - 14(2015). doi:10.1016/j.nima.2016.04.071
PET/PEN Blends of Industrial Interest as Barrier Materials. Part I. Many-Scale Molecular Modeling of PET/PEN Blends
2006
Mesoscale molecular simulations, based on parameters obtained through atomistic molecular dynamics and Monte Carlo calculations, have been used for modeling and predicting the behavior of PET/PEN blends. Different simulations have been performed in order to study and compare pure homopolymer blends with blends characterized by the presence of PET/PEN block copolymers acting as compatibilizer. A many-scale molecular modeling strategy was devised to evaluate PET/PEN blend characteristics, simulate phase segregation in pure PET/PEN blends, and demonstrate the improvement of miscibility due to the presence of the transesterification reaction products. The behavior of distribution densities and …
QPO emission from moving hot spots on the surface of neutron stars: a model
2009
We present recent results of 3D magnetohydrodynamic simulations of neutron stars with small misalignment angles, as regards the features in lightcurves produced by regular movements of the hot spots during accretion onto the star. In particular, we show that the variation of position of the hot spot created by the infalling matter, as observed in 3D simulations, can produce high frequency Quasi Periodic Oscillations with frequencies associated with the inner zone of the disk. Previously reported simulations showed that the usual assumption of a fixed hot spot near the polar region is valid only for misalignment angles relatively large. Otherwise, two phenomena challenge the assumption: one …
Energy-energy correlations in hadronic final states from Z0 decays
1990
We have studied the energy-energy angular correlations in hadronic final states from Z0 decay using the DELPHI detector at LEP. From a comparison with Monte Carlo calculations based on the exact second order QCD matrix element and string fragmentation we find that Λ(5)/MS = 104-20 +25 (stat.)-20 +25(syst.)-00 +30(theor.) MeV, which corresponds to αs(91 GeV) = 0.106± 0.003 (stat.)±0.003(syst.)-0.000 +0.003(theor.). The theoretical error stems from different choices for the renormalization scale of αs. In the Monte Carlo simulation the scale of αs as well as the fragmentation parameters have been optimized to described reasonably well all aspects of multihadron production.