Molecular Dynamics of Dissolution of a 36-Chain Cellulose Iβ Microfibril at Different Temperatures above the Critical Pressure of Water

The variation of molar conductance versus mole ratio for (kryptofix 22DD·La)3+ complex in methanol solution at different temperatures is in accordance with the variation of pair correlation function of oxygen atoms.

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Self-diffusion of lignite/water under different temperatures and pressure: A molecular dynamics study

Modern Physics Letters B ◽

10.1142/s021798491550253x ◽

2016 ◽

Vol 30 (01) ◽

pp. 1550253 ◽

Cited By ~ 2

Author(s):

Xinjian Liu ◽

Yu Jin ◽

Congliang Huang ◽

Jingfeng He ◽

Zhonghao Rao ◽

...

Keyword(s):

Molecular Dynamics ◽

Water System ◽

Simulation Method ◽

The Self ◽

Dynamics Simulation ◽

Low Rank ◽

Self Diffusion ◽

Change Mechanism ◽

Different Temperatures ◽

Temperature And Pressure

Temperature and pressure have direct and remarkable implications for drying and dewatering effect of low rank coals such as lignite. To understand the microenergy change mechanism of lignite, the molecular dynamics simulation method was performed to study the self-diffusion of lignite/water under different temperatures and pressure. The results showed that high temperature and high pressure can promote the diffusion of lignite/water system, which facilitates the drying and dewatering of lignite. The volume and density of lignite/water system will increase and decrease with temperature increasing, respectively. Though the pressure within simulation range can make lignite density increase, the increasing pressure showed a weak impact on variation of density.

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Structural changes in the molecular sheets along (hk0) planes derived from cellulose Iβ by molecular dynamics simulations

Cellulose ◽

10.1007/s10570-013-9915-5 ◽

2013 ◽

Vol 20 (3) ◽

pp. 1089-1098 ◽

Cited By ~ 8

Author(s):

Hitomi Miyamoto ◽

Chihiro Yamane ◽

Kazuyoshi Ueda

Keyword(s):

Molecular Dynamics ◽

Molecular Dynamics Simulations ◽

Structural Changes ◽

Cellulose Iβ ◽

Dynamics Simulations

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The β-cyclodextrin/benzene complex and its hydrogen bonds – a theoretical study using molecular dynamics, quantum mechanics and COSMO-RS

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.9.15 ◽

2013 ◽

Vol 9 ◽

pp. 118-134 ◽

Cited By ~ 19

Author(s):

Jutta Erika Helga Köhler ◽

Nicole Grczelschak-Mick

Keyword(s):

Molecular Dynamics ◽

Quantum Mechanics ◽

Hydrogen Bonds ◽

Md Simulations ◽

Benzene Molecule ◽

Glucose Unit ◽

Hand Orientation ◽

Different Temperatures ◽

Dynamics Simulations ◽

The Right

Four highly ordered hydrogen-bonded models of β-cyclodextrin (β-CD) and its inclusion complex with benzene were investigated by three different theoretical methods: classical quantum mechanics (QM) on AM1 and on the BP/TZVP-DISP3 level of approximation, and thirdly by classical molecular dynamics simulations (MD) at different temperatures (120 K and 273 to 300 K). The hydrogen bonds at the larger O2/O3 rim of empty β-CDs prefer the right-hand orientation, e.g., O3-H…O2-H in the same glucose unit and bifurcated towards …O4 and O3 of the next glucose unit on the right side. On AM1 level the complex energy was −2.75 kcal mol−1 when the benzene molecule was located parallel inside the β-CD cavity and −2.46 kcal mol−1 when it was positioned vertically. The AM1 HOMO/LUMO gap of the empty β-CD with about 12 eV is lowered to about 10 eV in the complex, in agreement with data from the literature. AM1 IR spectra displayed a splitting of the O–H frequencies of cyclodextrin upon complex formation. At the BP/TZVP-DISP3 level the parallel and vertical positions from the starting structures converged to a structure where benzene assumes a more oblique position (−20.16 kcal mol−1 and −20.22 kcal mol−1, resp.) as was reported in the literature. The character of the COSMO-RS σ-surface of β-CD was much more hydrophobic on its O6 rim than on its O2/O3 side when all hydrogen bonds were arranged in a concerted mode. This static QM picture of the β-CD/benzene complex at 0 K was extended by MD simulations. At 120 K benzene was mobile but always stayed inside the cavity of β-CD. The trajectories at 273, 280, 290 and 300 K certainly no longer displayed the highly ordered hydrogen bonds of β-CD and benzene occupied many different positions inside the cavity, before it left the β-CD finally at its O2/O3 side.

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Explosive Boiling of Water on a Hot Copper Plate: A Molecular Dynamics Simulation Study

Advanced Engineering Forum ◽

10.4028/www.scientific.net/aef.35.18 ◽

2020 ◽

Vol 35 ◽

pp. 18-28

Author(s):

Muhammad Rubayat Bin Shahadat ◽

A.K.M.M. Morshed

Keyword(s):

Molecular Dynamics ◽

Water Vapor ◽

Liquid Water ◽

Hydrophobic Surface ◽

Copper Plate ◽

Dynamics Simulation ◽

Hydrophilic Surface ◽

Explosive Boiling ◽

Different Temperatures ◽

Simulation Results

Non-equilibrium molecular dynamics simulations have been employed to study the explosive boiling phenomena of water over a hot copper plate. The molecular system was comprised of three sections: solid copper wall, liquid water, and water vapor. A few layers of the liquid water were placed on the solid Cu surface. The rest of the simulation box was filled with water vapor. Initially, the water molecules were equilibrated by using Berendsen thermostat at 298 K. Then heat was given to the copper plate at different temperatures so that explosive boiling occurs. After achieving the equilibrium by performing the previous two steps, the liquid water at 298 K is suddenly dropped on the hot plate. NVE ensemble was used in the simulation and the temperature of the copper plate was controlled to different temperatures with phantom atom thermostat. Four temperatures (400K, 500K, 650 K and 1000K) were taken to study the explosive boiling. The simulation results show that, the explosive boiling temperature of water on Cu plate is 500 K temperature. At this point, the energy flux was found 1.79x108 J/m3 which is very promising with the experimental results. Moreover, if the temperature of the surface was increased the explosive boiling occurred at a faster rate. The simulation results also show that explosive boiling occurs earlier for the hydrophilic surface than hydrophobic surface as for the hydrophilic surface the water attracted the Cu plate more than the hydrophobic surface and so the amount of energy transfer is more for the hydrophilic surface.

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MD INVESTIGATIONS FOR MECHANICAL PROPERTIES OF COPPER NANOWIRES WITH AND WITHOUT SURFACE DEFECTS

International Journal of Computational Methods ◽

10.1142/s0219876212400038 ◽

2012 ◽

Vol 09 (01) ◽

pp. 1240003 ◽

Cited By ~ 4

Author(s):

Y. T. GU ◽

H. F. ZHAN

Keyword(s):

Mechanical Properties ◽

Molecular Dynamics ◽

Yield Strength ◽

Yield Point ◽

Surface Defects ◽

Volume Ratio ◽

Strain Rates ◽

Copper Nanowires ◽

Dislocation Source ◽

Different Temperatures

Based on the molecular dynamics (MD) method, the single-crystalline copper nanowire with different surface defects is investigated through tension simulation. For comparison, the MD tension simulations of perfect nanowire are first carried out under different temperatures, strain rates, and sizes. It has concluded that the surface–volume ratio significantly affects the mechanical properties of nanowire. The surface defects on nanowires are then systematically studied in considering different defect orientation and distribution. It is found that the Young's modulus is the insensitive of surface defects. However, the yield strength and yield point show a significant decrease due to the different defects. Different defects are observed to serve as a dislocation source.

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