Insights into interphase thickness characterization for graphene/epoxy nanocomposites: a molecular dynamics simulation

2019 ◽  
Vol 21 (36) ◽  
pp. 19890-19903 ◽  
Author(s):  
Abolfazl Alizadeh Sahraei ◽  
Abdol Hadi Mokarizadeh ◽  
Daniel George ◽  
Denis Rodrigue ◽  
Majid Baniassadi ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Density Profile ◽  
Mass Density ◽  
Dynamics Simulation ◽  
Epoxy Nanocomposites ◽  
Local Mass ◽  
Mass Density Profile

This paper presents a methodology to systematically quantify the interphase thickness in epoxy nanocomposites using local mass density profile.

Molecular Dynamics Simulation Study of Lecithin Inhibiting Hydrate-Dissociation

2017 ◽  
Vol 890 ◽  
pp. 252-259
Author(s):  
Le Wang ◽  
Guan Cheng Jiang ◽  
Xin Lin ◽  
Xian Min Zhang ◽  
Qi Hui Jiang
Keyword(s):  
Molecular Dynamics ◽  
Water Movement ◽  
Simulation Analysis ◽  
Mass Density ◽  
Dynamics Simulation ◽  
Dissociation Process ◽  
Hydrate Dissociation ◽  
Hydrocarbon Chains ◽  
Dynamics Simulations ◽  
Mass Density Profile

Molecular dynamics simulations are used to study the dissociation inhibiting mechanism of lecithin for structure I hydrates. Adsorption characteristics of lecithin and PVP (poly (N-vinylpyrrolidine)) on the hydrate surfaces were performed in the NVT ensemble at temperatures of 277K and the hydrate dissociation process were simulated in the NPT ensemble at same temperature. The results show that hydrate surfaces with lecithin is more stable than the ones with PVP for the lower potential energy. The conformation of lecithin changes constantly after the balanced state is reached while the PVP molecular dose not. Lecithin molecule has interaction with lecithin nearby and hydrocarbon-chains of lecithin molecules will form a network to prevent the diffusion of water and methane molecules, which will narrow the available space for hydrate methane and water movement. Compared with PVP-hydrate simulation, analysis results (snapshots and mass density profile) of the dissociation simulations show that lecithin-hydrate dissociates more slowly.

Effect of Nanocellulose on Water-Oil Interfacial Tension

2021 ◽  
Vol 874 ◽  
pp. 13-19
Author(s):  
Mia Ledyastuti ◽  
Joseph Jason ◽  
Reza Aditama
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Interfacial Tension ◽  
Density Profile ◽  
Oil Recovery ◽  
Pure Water ◽  
Dynamics Simulation ◽  
Interface Tension ◽  
Determinant Factor ◽  
Natural Emulsifier

Interfacial tension is an important parameter in enhanced oil recovery (EOR). The interaction between water and oil phase is a determinant factor of the interfacial tension. The interfacial tension changes if another component is added to the water-oil system. This study investigates the effect of adding nanocellulose to the water-oil system. To determine the molecular interactions that occur, a molecular dynamics simulation was carried out using the GROMACS-2018 software. The simulation shows that addition of nanocellulose slightly decreases the water-oil interface tension. Further, based on the density profile, nanocellulose may act as an emulsifier due to its geometric position in the water-oil interface. This is similar to asphaltene, which is a natural emulsifier in crude oil. The nanocellulose performs better in the presence of 1% NaCl as compared to pure water.

Molecular dynamics simulation of plastic deformation in polyethylene under uniaxial and biaxial tension

2021 ◽  
pp. 146442072110458
Author(s):  
Yi Zhang ◽  
Liang Qiao ◽  
Junming Fan ◽  
Shifeng Xue ◽  
PY Ben Jar
Keyword(s):  
Molecular Dynamics ◽  
Plastic Deformation ◽  
Molecular Dynamics Simulation ◽  
Strain Rate ◽  
Strain Softening ◽  
Biaxial Tension ◽  
Mass Density ◽  
The Other ◽  
Dynamics Simulation ◽  
Low Strain Rate

Plastic deformation of polyethylene in uniaxial and biaxial loading conditions is studied using molecular dynamics simulation. Effects of tensile strain rates from 1 × 105 to 1 × 109 s−1, and mass density in the range of 0.923–0.926 g/cm3 on mechanical behaviour and microstructure evolution are examined. Two biaxial tensile deformation modes are considered. One is through simultaneous stretching in both the x and y directions and the other sequential stretching, firstly in the x-direction and then in the y-direction while strain in the x-direction remains constant. Tangent modulus and yield stress that are determined using the stress–strain curves from the molecular dynamics simulation show a strong dependence on the deformation mode, strain rate and mass density, and all are in good agreement with results from the experimental testing, including fracture behaviour which is ductile at a low strain rate but brittle at a high strain rate. Furthermore, the study suggests that the stress–strain curves under uniaxial tension and simultaneous biaxial tension at a relatively low strain rate contain four distinguishable regions, for elastic, yield, strain softening and strain hardening, respectively, whereas under sequential biaxial tension, stress increases monotonically with the increase of strain, without noticeable yielding, strain softening or strain hardening behaviour. The molecular dynamics simulation also suggests that an increase in the strain rate enhances the possibility of cavitation. Under simultaneous biaxial tension, with the strain rate increasing from 1 × 106 to 1 × 109 s−1, the molecular dynamics simulation shows that polyethylene failure changes from a local to a global phenomenon, accompanied by a decrease of the void size and increase of uniformity in the void distribution. Under sequential biaxial tension, on the other hand, the density of the cavities is clearly reduced.

scholarly journals Lysine Dendrigraft Nanocontainers. Influence of Topology on Their Size and Internal Structure

Pharmaceutics ◽  
2018 ◽  
Vol 10 (3) ◽  
pp. 129 ◽  
Author(s):  
Boris Okrugin ◽  
Maxim Ilyash ◽  
Denis Markelov ◽  
Igor Neelov
Keyword(s):  
Drug Delivery ◽  
Molecular Dynamics ◽  
Molecular Weight ◽  
Molecular Dynamics Simulation ◽  
Density Profile ◽  
Simulation Study ◽  
Biomedical Applications ◽  
Dynamics Simulation ◽  
Third Generation ◽  
Internal Structures

Poly-l-ysine dendrigrafts are promising systems for biomedical applications due to their biodegradability, biocompatibility, and similarity to dendrimers. There are many papers about the use of dendrigrafts as nanocontainers for drug delivery. At the same time, the number of studies about their physical properties is limited, and computer simulations of dendrigrafts are almost absent. This paper presents the results of a systematic molecular dynamics simulation study of third-generation lysine dendrigrafts with different topologies. The size and internal structures of the dendrigrafts were calculated. We discovered that the size of dendrigrafts of the same molecular weight depends on their topology. The shape of all studied dendrigrafts is close to spherical. Density profile of dendrigrafts depends on their topology.

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