scholarly journals Coarse grained modeling of nanostructure and asphaltene aggregation in asphalt binder using dissipative particle dynamics

2022 ◽  
Vol 314 ◽  
pp. 125605
Author(s):  
Jin Tang ◽  
Hao Wang
2013 ◽  
Vol 12 (02) ◽  
pp. 1250111 ◽  
Author(s):  
HAILONG XU ◽  
QIUYU ZHANG ◽  
HEPENG ZHANG ◽  
BAOLIANG ZHANG ◽  
CHANGJIE YIN

Dissipative particle dynamics (DPD) was initially used to simulate the polystyrene/nanoparticle composite microspheres (PNCM) in this paper. The coarse graining model of PNCM was established. And the DPD parameterization of the model was represented in detail. The DPD repulsion parameters were calculated from the cohesive energy density which could be calculated by amorphous modules in Materials Studio. The equilibrium configuration of the simulated PNCM shows that the nanoparticles were actually "modified" with oleic acid and the modified nanoparticles were embedded in the bulk of polystyrene. As sodium dodecyl sulfate (SDS) was located in the interface between water and polystyrene, the hydrophilic head of SDS stretched into water while the hydrophobic tailed into polystyrene. All simulated phenomena were consistent with the experimental results in preparation of polystyrene/nanoparticles composite microspheres. The effect of surface modification of nanoparticles on its dispersion in polystyrene matrix was also studied by adjusting the interaction parameters between the OA and NP beads. The final results indicated that the nanoparticles removed from the core of composite microsphere to the surface with increase of a OA-NP . All the simulated results demonstrated that our coarse–grained model was reasonable.


Soft Matter ◽  
2021 ◽  
Author(s):  
Rakesh K Vaiwala ◽  
Ganapathy Ayappa

A coarse-grained force field for molecular dynamics simulations of native structures of proteins in a dissipative particle dynamics (DPD) framework is developed. The parameters for bonded interactions are derived by...


2017 ◽  
Vol 44 (7) ◽  
pp. 540-550 ◽  
Author(s):  
Rakesh Vaiwala ◽  
Sameer Jadhav ◽  
Rochish Thaokar

2012 ◽  
Vol 11 (3) ◽  
pp. 709-725 ◽  
Author(s):  
Licui Chen ◽  
Lianghui Gao ◽  
Weihai Fang ◽  
Leonardo Golubovic

AbstractIn the present article, coarse grained Dissipative Particle Dynamics simulation with implementation of electrostatic interactions is developed in constant pressure and surface tension ensemble to elucidate how the antimicrobial peptide molecules affect bilayer cell membrane structure and kill bacteria. We find that peptides with different chemical-physical properties exhibit different membrane obstructing mechanisms. Peptide molecules can destroy vital functions of the affected bacteria by translocating across their membranes via worm-holes, or by associating with membrane lipids to form hydrophilic cores trapped inside the hydrophobic domain of the membranes. In the latter model, the affected membranes are strongly buckled, in accord with very recent experimental observations [G. E. Fantner et al., Nat. Nanotech., 5 (2010), pp. 280-285].


2008 ◽  
Vol 1135 ◽  
Author(s):  
Taiga Seki ◽  
Noriyoshi Arai ◽  
Taku Ozawa ◽  
Tomoko Shimada ◽  
Kenji Yasuoka ◽  
...  

ABSTRACTA coarse-grained model of peptide amphiphiles (PA) dissolved in aqueous solution was presented, where the effects of PA concentration, temperature and shear stress upon the self-assembly of PA were numerically studied by dissipative particle dynamics (DPD) simulation. We technically investigate the repulsion parameter aHW which indicates the repulsion force between the hydrophilic head of PA and water molecules, hence, at the same time, indicating the change in temperature. It was found that aHW played an important role in the self-assembly dynamics and in the resulting micro-structures of PA. By imposing shear strain on the simulation system, the formation of wormlike PA micelles was accelerated. The simulation results were in good agreement with our previous experimental results and the mechanism of shear-induced transition was proposed.


Author(s):  
Toru Yamada ◽  
Anurag Kumar ◽  
Yutaka Asako ◽  
Mohammad Faghri

Dissipative particle dynamics (DPD) with energy conservation was applied to simulate forced convection in parallel-plate channels with boundary conditions of constant wall temperature (CWT) and constant wall heat flux (CHF). DPD is a coarse-grained version of molecular dynamics. An additional governing equation for energy conservation was solved along with conventional DPD equations where inter-particle heat flux accounts for changes in mechanical and internal energies when particles interact with surrounding particles. The solution domain was considered to be two-dimensional with periodic boundary condition in the flow direction. Additional layers of particles on top and bottom of the channel were utilized to apply no-slip velocity and temperature boundary conditions. The governing equations for energy conservation were modified based on periodic fully developed velocity and temperature conditions. The results were shown via velocity and temperature profiles across the channel cross section. The Nusselt numbers were calculated from the temperature gradient at the wall using a second order accurate forward difference approximation. The results agreed well with the exact solutions to within 2.3%.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
P. M. Pieczywek ◽  
W. Płaziński ◽  
A. Zdunek

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.


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