scholarly journals Understanding water interactions with organic surfaces: environmental molecular beam and molecular dynamics studies of the water–butanol system

2019 ◽  
Vol 21 (3) ◽  
pp. 1141-1151 ◽  
Author(s):  
Sofia M. Johansson ◽  
Josip Lovrić ◽  
Xiangrui Kong ◽  
Erik S. Thomson ◽  
Panos Papagiannakopoulos ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Beam ◽  
Water Molecules ◽  
System P ◽  
Organic Surfaces

The scattering, fast and slow desorption of water molecules from solid and liquid butanol surfaces are investigated by experiments and simulations.

scholarly journals The Impact of the Electric Field on Surface Condensation of Water Vapor: Insight from Molecular Dynamics Simulation

Nanomaterials ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 64 ◽  
Author(s):  
Qin Wang ◽  
Hui Xie ◽  
Zhiming Hu ◽  
Chao Liu
Keyword(s):  
Molecular Dynamics ◽  
Water Vapor ◽  
Electric Field ◽  
Intermolecular Forces ◽  
Dynamics Simulation ◽  
Water Molecules ◽  
Attraction Force ◽  
Condensation Rate ◽  
Shape Transformation ◽  
The Impact

In this study, molecular dynamics simulations were carried out to study the coupling effect of electric field strength and surface wettability on the condensation process of water vapor. Our results show that an electric field can rotate water molecules upward and restrict condensation. Formed clusters are stretched to become columns above the threshold strength of the field, causing the condensation rate to drop quickly. The enhancement of surface attraction force boosts the rearrangement of water molecules adjacent to the surface and exaggerates the threshold value for shape transformation. In addition, the contact area between clusters and the surface increases with increasing amounts of surface attraction force, which raises the condensation efficiency. Thus, the condensation rate of water vapor on a surface under an electric field is determined by competition between intermolecular forces from the electric field and the surface.

scholarly journals Electrical Breakdown Mechanism of Transformer Oil with Water Impurity: Molecular Dynamics Simulations and First-Principles Calculations

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 123
Author(s):  
Bin Cao ◽  
Ji-Wei Dong ◽  
Ming-He Chi
Keyword(s):  
Molecular Dynamics ◽  
Thermal Diffusion ◽  
First Principles ◽  
Electrical Breakdown ◽  
Transformer Oil ◽  
Water Molecules ◽  
Conducting Channel ◽  
Breakdown Mechanism ◽  
Water Impurity ◽  
Dynamics Simulations

Water impurity is the essential factor of reducing the insulation performance of transformer oil, which directly determines the operating safety and life of a transformer. Molecular dynamics simulations and first-principles electronic-structure calculations are employed to study the diffusion behavior of water molecules and the electrical breakdown mechanism of transformer oil containing water impurities. The molecular dynamics of an oil-water micro-system model demonstrates that the increase of aging acid concentration will exponentially expedite thermal diffusion of water molecules. Density of states (DOS) for a local region model of transformer oil containing water molecules indicates that water molecules can introduce unoccupied localized electron-states with energy levels close to the conduction band minimum of transformer oil, which makes water molecules capable of capturing electrons and transforming them into water ions during thermal diffusion. Subsequently, under a high electric field, water ions collide and impact on oil molecules to break the molecular chain of transformer oil, engendering carbonized components that introduce a conduction electronic-band in the band-gap of oil molecules as a manifestation of forming a conductive region in transformer oil. The conduction channel composed of carbonized components will be eventually formed, connecting two electrodes, with the carbonized components developing rapidly under the impact of water ions, based on which a large number of electron carriers will be produced similar to “avalanche” discharge, leading to an electrical breakdown of transformer oil insulation. The water impurity in oil, as the key factor for forming the carbonized conducting channel, initiates the electric breakdown process of transformer oil, which is dominated by thermal diffusion of water molecules. The increase of aging acid concentration will significantly promote the thermal diffusion of water impurities and the formation of an initial conducting channel, accounting for the degradation in dielectric strength of insulating oil containing water impurities after long-term operation of the transformer.

Unraveling cGAS catalytic mechanism upon DNA activation through molecular dynamics simulations

2021 ◽  
Author(s):  
Jordi Soler ◽  
Pedro Paiva ◽  
Maria Joao Joao Ramos ◽  
Pedro Alexandrino Fernandes ◽  
Marie Brut
Keyword(s):  
Molecular Dynamics ◽  
Dna Binding ◽  
Molecular Dynamics Simulations ◽  
Cyclic Gmp ◽  
Catalytic Mechanism ◽  
System P ◽  
Dynamics Simulations ◽  
Cyclic Dinucleotide

Cyclic GMP-AMP Synthase (cGAS) is activated upon DNA binding and catalyzes the synthesis of 2’,3’-cGAMP from GTP and ATP. This cyclic dinucleotide is a messenger that triggers the autoimmune system...

scholarly journals Origin and control of ionic hydration patterns in nanopores

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Miraslau L. Barabash ◽  
William A. T. Gibby ◽  
Carlo Guardiani ◽  
Alex Smolyanitsky ◽  
Dmitry G. Luchinsky ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Distribution Functions ◽  
Water Molecules ◽  
Surrounding Water ◽  
Ionic Hydration ◽  
Hydration Shells ◽  
Water Layers ◽  
Dynamics Simulations ◽  
And Control

AbstractIn order to permeate a nanopore, an ion must overcome a dehydration energy barrier caused by the redistribution of surrounding water molecules. The redistribution is inhomogeneous, anisotropic and strongly position-dependent, resulting in complex patterns that are routinely observed in molecular dynamics simulations. Here, we study the physical origin of these patterns and of how they can be predicted and controlled. We introduce an analytic model able to predict the patterns in a graphene nanopore in terms of experimentally accessible radial distribution functions, giving results that agree well with molecular dynamics simulations. The patterns are attributable to a complex interplay of ionic hydration shells with water layers adjacent to the graphene membrane and with the hydration cloud of the nanopore rim atoms, and we discuss ways of controlling them. Our findings pave the way to designing required transport properties into nanoionic devices by optimising the structure of the hydration patterns.

scholarly journals Molecular dynamics study of pressure-driven water transport through graphene bilayers

2016 ◽  
Vol 18 (3) ◽  
pp. 1886-1896 ◽  
Author(s):  
Bo Liu ◽  
Renbing Wu ◽  
Julia A. Baimova ◽  
Hong Wu ◽  
Adrian Wing-Keung Law ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
High Pressure ◽  
Water Transport ◽  
Layered Structures ◽  
Water Molecules ◽  
Flow Rates ◽  
Ultra High Pressure ◽  
Pressure Driven Flow ◽  
Pressure Driven

Water molecules form layered structures inside graphene bilayers and ultra-high pressure-driven flow rates can be observed.

Hormones Nanofiltration in Carbon Nanotubes and Boron Nitride Nanotubes Using Uniform External Electric Field Through Molecular Dynamics

2021 ◽  
Vol 21 (11) ◽  
pp. 5499-5509
Author(s):  
Rosely Maria dos Santos Cavaleiro ◽  
Tiago da Silva Arouche ◽  
Phelipe Seiichi Martins Tanoue ◽  
Tais Souza Sá Pereira ◽  
Raul Nunes de Carvalho Junior ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Molecular Dynamics ◽  
Boron Nitride ◽  
Electric Field ◽  
Field Potential ◽  
Boron Nitride Nanotubes ◽  
Attractive Potential ◽  
Water Molecules ◽  
Computer Simulation Study ◽  
Simulation Time

Hormones are a dangerous group of molecules that can cause harm to humans. This study based on classical molecular dynamics proposes the nanofiltration of wastewater contaminated by hormones from a computer simulation study, in which the water and the hormone were filtered in two single-walled nanotube compositions. The calculations were carried out by changing the intensities of the electric field that acted as a force exerting pressure on the filtration along the nanotube, in the simulation time of 100 ps. The hormones studied were estrone, estradiol, estriol, progesterone, ethinylestradiol, diethylbestrol, and levonorgestrel in carbon nanotubes (CNTs) and boron nitride (BNNTs). The most efficient nanofiltrations were for fields with low intensities in the order of 10-8 au and 10-7 au. The studied nanotubes can be used in membranes for nanofiltration in water treatment plants due to the evanescent field potential caused by the action of the electric field inside. Our data showed that the action of EF in conjunction with the van der Walls forces of the nanotubes is sufficient to generate the attractive potential. Evaluating the transport of water molecules in CNTs and BNNTs, under the influence of the electric field, a sequence of simulations with the same boundary conditions was carried out, seeking to know the percentage of water molecules filtered in the nanotubes.

Sign in / Sign up

Export Citation Format

Share Document