An Efficient Dissipative Particle Dynamics-Based Algorithm for Simulating Ferromagnetic Colloidal Suspensions

2015 ◽  
Vol 11 (2) ◽  
Author(s):  
Wuming Li ◽  
Jie Ouyang ◽  
Qingsheng Liu
Keyword(s):  
Magnetic Particles ◽  
Colloidal Suspension ◽  
Dissipative Particle Dynamics ◽  
Particle Interaction ◽  
Colloidal Suspensions ◽  
Particle Dynamics ◽  
Distribution Functions ◽  
Time Step ◽  
The Mean ◽  
Aggregate Structures

In this paper, the algorithm, Euler scheme-the modified velocity-verlet algorithm (ES-MVVA) based on dissipative particle dynamics (DPD) method, is applied to simulate a two-dimensional ferromagnetic colloidal suspension. The very desirable aggregate structures of magnetic particles are obtained by using the above-mentioned algorithm, which are in qualitatively good agreement with those in the literature obtained by other simulation methods for different magnetic particle–particle interaction strengths. At the same time, the radial distribution functions of magnetic particles and the mean equilibrium temperatures of the system are also calculated. Next, the mean equilibrium velocities of magnetic and dissipative particles are calculated, by comparing the results obtained by ES-MVVA with those obtained by other algorithm for different time step sizes, it shows the validity and good accuracy of the present algorithm. So, the DPD-based algorithm presented in this paper is a powerful tool for simulation of magnetic colloidal suspensions.

Magnetic Targeting of Particle Transport Under Pulsatile Flow

2006 ◽  
Author(s):  
Alicia Williams ◽  
Ashok Sinha ◽  
Pavlos Vlachos ◽  
Ishwar K. Puri
Keyword(s):  
Magnetic Field ◽  
Pulsatile Flow ◽  
Magnetic Particles ◽  
Colloidal Suspension ◽  
Magnetic Field Gradient ◽  
Colloidal Suspensions ◽  
Glass Tube ◽  
Superparamagnetic Nanoparticles ◽  
Magnetic Drug Targeting ◽  
The Magnetic Field

Magnetic Drug Targeting (MDT) has been shown to be a promising technique to effectively deliver medicinal drugs via functionalized [1] magnetic particles to target sites during the treatment of cancer and other diseases [2,3,4]. In this paper, we investigate the interaction of steady and pulsatile flows injected with a ferrofluid, which is a colloidal suspension of superparamagnetic nanoparticles in a glass tube under the influence of a magnetic field. Ferrofluids are colloidal suspensions of single domain magnetic nanoparticles that are of the order of 10 nm in diameter. In this experiment, the ferrofluid particles were directed to a particular region of interest within a 10 mm diameter glass vessel by means of an applied localized magnetic field that originated outside of the vessel. The magnetic field was generated using a rare earth sintered permanent magnet which produced the magnetic field gradient required for inducing a body force on the volume of the ferrofluid. The experimental results reveal flows with rich dynamical phenomena. The aggregation of the ferrofluid produces a self-assembled hemispherical structure which dynamically interacts with the host flow. The aggregation generates an occlusion creating a flow field that is similar to that past an obstruction. However, since the structure itself is of a fluidic nature, it is subject to shear forces caused by the host fluid. In addition, the wake of the flow behind the aggregation creates vortices which are critical to study the stability of the ferrofluid aggregate. This paper presents a detailed investigation of the dynamics of the flow using Time-Resolved Digital Particle Image Velocimetry. To the best of the authors’ knowledge, these are the first quantitative, spatiotemporally resolved measurements documenting the interaction of a host fluid with a ferrofluid aggregate under steady or pulsatile flow conditions.

Comparison Between Theoretical Values and Simulation Results of Transport Coefficients for the Dissipative Particle Dynamics Method

2004 ◽  
Author(s):  
Akira Satoh
Keyword(s):  
Transport Coefficients ◽  
Dissipative Particle Dynamics ◽  
Planck Equation ◽  
Equation Of Motion ◽  
Particle Dynamics ◽  
Momentum Conservation ◽  
Distribution Functions ◽  
Fokker Planck Equation ◽  
Dynamics Method ◽  
Fokker Planck

In the present study, we have derived an expression for transport coefficients such as viscosity, from the equation of motion of dissipative particles. In the concrete, we have shown the Fokker-Planck equation in phase space, and macroscopic conservation equations such as the equation of continuity and the equation of momentum conservation. The basic equations of the single-particle and pair distribution functions have been derived using the Fokker-Planck equation. The solutions of these distribution functions have approximately been solved by the perturbation method under the assumption of molecular chaos. The expression of the viscosity due to dissipative forces has been obtained using the approximate solutions of the distribution functions. Also, we have conducted non-equilibrium dynamics simulations to investigate the influence of the parameters, which have appeared in defining the equation of motion in the dissipative particle dynamics method.

scholarly journals Dissipative particle dynamics model of homogalacturonan based on molecular dynamics simulations

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
P. M. Pieczywek ◽  
W. Płaziński ◽  
A. Zdunek
Keyword(s):  
Molecular Dynamics ◽  
Force Field ◽  
Large Scale ◽  
Dissipative Particle Dynamics ◽  
Three Dimensional ◽  
Structural Features ◽  
Particle Dynamics ◽  
Distribution Functions ◽  
Coarse Grained ◽  
Dynamics Model

Abstract In this study we present an alternative dissipative particle dynamics (DPD) parametrization strategy based on data extracted from the united-atom molecular simulations. The model of the homogalacturonan was designed to test the ability of the formation of large-scale structures via hydrogen bonding in water. The extraction of coarse-grained parameters from atomistic molecular dynamics was achieved by means of the proposed molecule aggregation algorithm based on an iterative nearest neighbour search. A novel approach to a time-scale calibration scheme based on matching the average velocities of coarse-grained particles enabled the DPD forcefield to reproduce essential structural features of homogalacturonan molecular chains. The successful application of the proposed parametrization method allowed for the reproduction of the shapes of radial distribution functions, particle velocities and diffusivity of the atomistic molecular dynamics model using DPD force field. The structure of polygalacturonic acid molecules was mapped into the DPD force field by means of the distance and angular bond characteristics, which closely matched the MD results. The resulting DPD trajectories showed that randomly dispersed homogalacturonan chains had a tendency to aggregate into highly organized 3D structures. The final structure resembled a three-dimensional network created by tightly associated homogalacturonan chains organized into thick fibres.

Systematic fine-tuning of dissipative particle dynamics for mesoscale semidilute and dense colloidal suspensions

2018 ◽  
Vol 510 ◽  
pp. 492-506 ◽  
Author(s):  
H. Hassanzadeh Afrouzi ◽  
Abouzar Moshfegh ◽  
Ashkan Javadzadegan ◽  
Maryam Mohammadi ◽  
Mousa Farhadi
Keyword(s):  
Dissipative Particle Dynamics ◽  
Colloidal Suspensions ◽  
Particle Dynamics ◽  
Fine Tuning

scholarly journals Orientation and Dispersion Evolution of Carbon Nanotubes in Ultra High Molecular Weight Polyethylene Composites under Extensional-Shear Coupled Flow: A Dissipative Particle Dynamics Study

Polymers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 154 ◽  
Author(s):  
Junxia Wang ◽  
Changlin Cao ◽  
Xiaochuan Chen ◽  
Shijie Ren ◽  
Yu Chen ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Molecular Weight ◽  
High Molecular Weight ◽  
Dissipative Particle Dynamics ◽  
Mean Square Displacement ◽  
Particle Dynamics ◽  
Distribution Functions ◽  
Coupled Flow ◽  
Uhmwpe Composites ◽  
Ultra High Molecular Weight

The property of carbon nanotubes (CNTs)-based composites are significantly dependent on the orientation and dispersion evolution of CNTs in the polymer matrix. In this work, the dissipative particle dynamics (DPD) simulations are employed to discover the orientation and dispersion evolution of CNTs in ultra–high molecular weight polyethylene (UHMWPE) under extensional–shear coupled flow conditions for the first time. In this paper, we investigate the roles of the increasing extensional-shear coupled rate in morphology of CNTs/UHMWPE composites by varying CNTs concentration and observe that the system under consideration lies in the same evolution morphologies. When comparing our results for various morphologies, we notice that the orientation is affected more significantly by changing the extensional-shear coupled rates. A good alignment appears with an increase of extensional-shear coupled rates, which transform it into ordered morphology. In addition, a higher extensional-shear coupled rate does not necessarily contribute to better dispersion even though CNTs concentration varies, as shown by the mean square displacement (MSD) and the relative concentration distribution functions of CNTs in CNTs/UHMWPE composites.

Analysis of the Interplay Between Sedimentation and Thermophoresis in the Presence of Convection in Colloidal Suspensions

2014 ◽  
Author(s):  
Mahmoud DarAssi ◽  
Layachi Hadji
Keyword(s):  
Volume Fraction ◽  
Colloidal Suspension ◽  
Colloidal Suspensions ◽  
Analytical Investigation ◽  
Solid Particles ◽  
Critical Conditions ◽  
Thermophoretic Force ◽  
The Mean ◽  
Set Up ◽  
Rayleigh Benard

We report results of an analytical investigation of linear convection in a nanofluid. We consider a colloidal suspension of solid particles in a Rayleigh-Bénard geometry set-up. The analysis is confined to the mass-dominated convection regime so that results are obtained through analytical means. Our findings depict the dependence of the critical conditions for convection onset as function of several parameters. Thus, the influence of several factors, such as the particle size, the mean volume fraction of particles, the thermophoretic force as well as the sedimentation force, on the instability onset is quantified.

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