57 research outputs found
Coupled coarse graining and Markov Chain Monte Carlo for lattice systems
We propose an efficient Markov Chain Monte Carlo method for sampling
equilibrium distributions for stochastic lattice models, capable of handling
correctly long and short-range particle interactions. The proposed method is a
Metropolis-type algorithm with the proposal probability transition matrix based
on the coarse-grained approximating measures introduced in a series of works of
M. Katsoulakis, A. Majda, D. Vlachos and P. Plechac, L. Rey-Bellet and
D.Tsagkarogiannis,. We prove that the proposed algorithm reduces the
computational cost due to energy differences and has comparable mixing
properties with the classical microscopic Metropolis algorithm, controlled by
the level of coarsening and reconstruction procedure. The properties and
effectiveness of the algorithm are demonstrated with an exactly solvable
example of a one dimensional Ising-type model, comparing efficiency of the
single spin-flip Metropolis dynamics and the proposed coupled Metropolis
algorithm.Comment: 20 pages, 4 figure
Evaluation of the potential accuracy of the pulsed radio signals source coordinate determination by the positioning system using a single UAV-sensor
An approach to determining the coordinates of pulsed radio signals sources by the positioningsystem in the application of a single unmanned aerial vehicles sensor is shown in this article. Therange-difference location method allows to determinate an informative coordinate parameter withoutretransmission and internal synchronization of receiving points. The result is achieved by improving thewell-known scientific and methodological apparatus with considering some features of the operationmode of pulsed radio signals sources. Presenting results of the simulation allow to estimate theinfluence of main input factors on the potential accuracy of the pulsed radio signal source coordinatedetermination
Combined Simulation and Experimental Study of Large Deformation of Red Blood Cells in Microfluidic Systems
Author manuscript; available in PMC 2012 March 1.We investigate the biophysical characteristics of healthy human red blood cells (RBCs) traversing microfluidic channels with cross-sectional areas as small as 2.7 × 3 μm. We combine single RBC optical tweezers and flow experiments with corresponding simulations based on dissipative particle dynamics (DPD), and upon validation of the DPD model, predictive simulations and companion experiments are performed in order to quantify cell deformation and pressure–velocity relationships for different channel sizes and physiologically relevant temperatures. We discuss conditions associated with the shape transitions of RBCs along with the relative effects of membrane and cytosol viscosity, plasma environments, and geometry on flow through microfluidic systems at physiological temperatures. In particular, we identify a cross-sectional area threshold below which the RBC membrane properties begin to dominate its flow behavior at room temperature; at physiological temperatures this effect is less profound.Singapore-MIT Alliance for Research and TechnologyUnited States. National Institutes of Health (National Heart, Lung, and Blood Institute Award R01HL094270
Everything you always wanted to know about SDPD⋆ (⋆but were afraid to ask)
An overview of the smoothed dissipative particle dynamics (SDPD) method is presented in a format that tries to quickly answer questions that often arise among users and newcomers. It is hoped that the status of SDPD is clarified as a mesoscopic particle model and its potentials and limitations are highlighted, as compared with other methods
Single-particle hydrodynamics in DPD: A new formulation
We present a new formulation of dissipative particle dynamics (DPD) that leads to correct hydrodynamics in flows around bluff bodies represented by a single particle. In particular, we introduce a shear drag coefficient and a corresponding term in the dissipative force, which along with the angular momentum incorporate non-central shear forces between particles and preserve angular momentum. We consider several prototype flows to verify the performance of the proposed formulation with comparisons against theoretical and continuum-based simulation results. Our method is similar to the Fluid Particle Method (FPM) of Espanol (Phys. Rev. E, 57 (1998) 2930) and it has the computational and implementation simplicity of the standard DPD approach
Combined Effects of Pulsatile Flow and Dynamic Curvature on Wall Shear Stress in a Coronary Artery Bifurcation Model
A three-dimensional model with simplified geometry for the coronary artery is presented. In particular, both..
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