scholarly journals Investigating the Compatibility of Various Components in Marine Low-Sulfur Fuel Oil by Molecular Dynamics Simulations

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Daping Zhou ◽  
Haijun Wei ◽  
Shuye Xue ◽  
Ye Qiu ◽  
Shen Wu ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Distribution Function ◽  
Radial Distribution Function ◽  
Radial Distribution ◽  
Md Simulations ◽  
Peak Height ◽  
Fuel Oil ◽  
Solubility Parameters ◽  
Heavy Fuel Oil ◽  
Low Sulfur

Asphaltene aggregation and precipitation are one of the major issues for marine low-sulfur fuel oil used on board. Many research studies have been carried out to investigate the aggregation behavior of asphaltene under different conditions, but the mechanism of asphaltene aggregation in low-sulfur fuel oil at the molecular level is still unclear. In this work, molecular dynamics (MD) simulations were performed to calculate the solubility parameters, intermolecular interaction energies, and radial distribution function (RDF) curves of each component in marine low-sulfur fuel oil to examine their mutual compatibility. Simulation results indicate that the solubility parameter of resin gains the highest value and it is close to asphaltene. The solubility parameters of aromatic, hexadecane, and saturate decrease successively. The interaction energy between resin and asphaltene molecules is higher than that between the same kind of molecules, which means that resin can inhibit the aggregation of asphaltene molecules. Typically, a light distillate component (hexadecane) is added to heavy fuel oil to yield low-sulfur oil, and our calculations reveal that this has a negative effect on asphaltene aggregation. Specifically, asphaltene is more likely to self-aggregate, as shown by the increase in peak height in the radial distribution function of the asphaltene-asphaltene pair. The findings of this study will provide theoretical support for the production of marine low-sulfur fuel.

Effect of Substrate Temperature and Incident Energy for Alloyzation of Co onto Cu(001) Substrate

2008 ◽  
Vol 47-50 ◽  
pp. 375-378 ◽  
Author(s):  
Zheng Han Hong ◽  
Shun Fa Hwang ◽  
Te Hua Fang
Keyword(s):  
Molecular Dynamics ◽  
Distribution Function ◽  
Substrate Temperature ◽  
Radial Distribution Function ◽  
Radial Distribution ◽  
Incident Energy

The mixing situation of Co atoms implanting onto Cu(001) substrate is investigated with regard to incident energy and substrate temperature by molecular dynamics. The results indicate that higher substrate temperature and/or incident energy will result in higher intermixing between the incident atoms and the substrate atoms. Furthermore, the value of the first peak of the radial distribution function (RDF) becomes lower and wider for the Co-Cu system as the substrate temperature and/or incident energy are increased.

scholarly journals Molecular Dynamics Study on the Leaching of Zinc-Bearing Dust Sludge by Choline Chloride-Malonic Acid

Minerals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1080
Author(s):  
Jinxia Zhang ◽  
Chao Yang ◽  
Fusheng Niu ◽  
Shuling Gao ◽  
Jiajing Dong
Keyword(s):  
Molecular Dynamics ◽  
Distribution Function ◽  
Metal Oxides ◽  
Radial Distribution Function ◽  
Malonic Acid ◽  
Radial Distribution ◽  
Choline Chloride ◽  
Leaching Rate ◽  
Single Factor ◽  
Leaching Experiments

Molecular dynamics of the interaction between four metal oxides (ZnO, Fe2O3, Al2O3, and CaO) present in zinc-bearing dust sludge and choline chloride (ChCl)-malonic acid (MA)(1:2) was studied in this work using Materials Studio software. The interaction mechanism was revealed by analyzing the interaction energy and radial distribution function from the perspective of quantum mechanics, and the simulation results were verified by single factor leaching experiments. The calculation results show that the complete cleavage surface of the four metal oxides is the (001) surface, and ChCl-2MA forms a stable structure with multiple intermolecular hydrogen bonds centered on the chlorine atom. The dynamic simulation of the interaction model shows that strength of interaction between ChCl-2MA and the four metal oxides follows the order: ZnO > Fe2O3 > Al2O3 > CaO. ChCl-2MA mainly interacts with ZnO by chemical adsorption, while ChCl-2MA mainly interacts with Fe2O3, Al2O3, and CaO by physical adsorption. The radial distribution function shows that Cl in ChCl-2MA and C=O in MA form chemical bonds with Zn in ZnO, and the choline cation (Ch+) forms C-H···O with ZnO. Among these bonds, the Cl-Zn bond energy is stronger. During the interaction between ChCl-2MA and Fe2O3 and Al2O3, O-H···O and C-H···O are formed and interact with CaO by van der Waals force. Single factor leaching experiments show that, under the same leaching conditions, the leaching rate of ZnO by ChCl-2MA is greater than 90%, while the leaching rate of Fe2O3, Al2O3, and CaO is about 10%. These results indicate good selectivity of ChCl-2MA for ZnO in the zinc-bearing dust sludge. The above conclusions have important theoretical significance and provide an in-depth understanding of the leaching mechanisms of zinc-bearing dust sludge in deep eutectic solvents.

Study on Ni/Al Interface Diffusion at Initial Time by Using Molecular Dynamics Method

2011 ◽  
Vol 391-392 ◽  
pp. 42-45 ◽  
Author(s):  
Yu Mei Dai ◽  
Sheng Long Zhu ◽  
Fu Hui Wang
Keyword(s):  
Molecular Dynamics ◽  
Distribution Function ◽  
Radial Distribution Function ◽  
Radial Distribution ◽  
Diffusion Theory ◽  
Interface Reaction ◽  
Initial Time ◽  
Diffusion Layer Thickness ◽  
Interface Diffusion ◽  
The Matrix

The basic theory of molecular dynamics and interface diffusion theory are used to simulate metal Ni/Al interface diffusion. The position image of the interface diffusion atoms and radial distribution function curve of Ni/Al interface reaction at initial time at a high temperature can be got. Through these images of diffusion atoms position, it is observed that there is a lot of change during the simulation process. The Al atoms layer of the matrix begins to melt at first. Ni atoms in the matrix begin to diffuse outward rapidly in large quantities. Al atoms overall diffuse to one side of the matrix at a relatively low speed, inter-diffusion layer thickness increases continuously and inter-diffusion atoms are solidified gradually from one side of the matrix to the surface. The process of change has been further verified in the corresponding radial distribution function curves. These conclusions can provide a theoretical reference for the technology of new materials preparation and the expansion of the environment of Ni/Al use.

Molecular dynamics studies the effect of structure MgSiO3 bulk on formation process geology of the Earth

2019 ◽  
Vol 08 (03) ◽  
pp. 1950011 ◽  
Author(s):  
Nguyen Trong Dung ◽  
Nguyen Chinh Cuong ◽  
Duong Quoc Van
Keyword(s):  
Molecular Dynamics ◽  
Distribution Function ◽  
Total Energy ◽  
Radial Distribution Function ◽  
Radial Distribution ◽  
Formation Process ◽  
Pair Interaction ◽  
Effect Of Temperature ◽  
Angle Distribution ◽  
The Earth

The paper studies the effect of temperature ([Formula: see text]), ([Formula: see text], 3200, 4000, 5000, 6000, 7000[Formula: see text]K) at pressure [Formula: see text][Formula: see text]GPa; pressure ([Formula: see text]), ([Formula: see text], 100, 200, 300, 350, 400[Formula: see text]GPa) at [Formula: see text][Formula: see text]K and thermal annealing time ([Formula: see text]), [Formula: see text][Formula: see text]ps (after 105 steps) at [Formula: see text][Formula: see text]K, [Formula: see text][Formula: see text]Gpa) on the structure of MgSiO3 bulk 3000 atoms by Molecular Dynamics (MD) simulation using Born–Mayer (BM) pair interaction potential and periodic boundary conditions. The structural results are analyzed through the Radial Distribution Function (RDF), the Coordination Number (CN), the angle distribution, size ([Formula: see text]), total energy of the system ([Formula: see text]) and the bonding lengths. The results show that the temperature and pressure had influenced the structural properties of MgSiO3 bulk and formation process geology of the Earth. In addition, the center of the Earth with [Formula: see text][Formula: see text]K and [Formula: see text][Formula: see text]GPa has appearance and disappearance of the Si–Si, Si–O, O–O, Si–Mg, O–Mg, Mg–Mg bonds and SiO4, SiO5, SiO6, MgO3, MgO4, MgO5, MgO6, MgO7, MgO8, MgO9, MgO[Formula: see text], MgO[Formula: see text], MgO[Formula: see text] angle distributions. When increasing the depth of the Earth’s surface [Formula: see text] lead to size [Formula: see text] of MgSiO3 decreases, total energy of the system ([Formula: see text]) increases, position of first peak of Radial Distribution Function (RDF) is [Formula: see text], height of RDF is [Formula: see text] varies greatly with [Formula: see text] from [Formula: see text][Formula: see text]km to [Formula: see text][Formula: see text]km, gradually decreasing with [Formula: see text] from [Formula: see text][Formula: see text]km to [Formula: see text][Formula: see text]km and the smallest structural change with [Formula: see text][Formula: see text]km that shows has influence affects on the geological formation of the Earth.

Radial Distribution Function of Liquid Sodium

1982 ◽  
Vol 37 (6) ◽  
pp. 594-597
Author(s):  
M. Rami Reddy
Keyword(s):  
Molecular Dynamics ◽  
Integral Equation ◽  
Distribution Function ◽  
Perturbation Theory ◽  
Radial Distribution Function ◽  
Radial Distribution ◽  
Pair Potential ◽  
Liquid Sodium ◽  
Oscillatory Potential ◽  
Molecular Dynamics Calculations

Abstract The radial distribution function of liquid sodium has been studied by considering the integral equation Perturbation Theory of Madden and Fitts for the reference part and the optimised cluster theory for the attractive part of the pair potential. Calculations were carried out for the long range oscillatory potential of Schiff. The calculated results are compared with the molecular dynamics calculations HTA, OCT and with experiment. The agreement was found to be satisfactory.

Reconciliation of the microcrystalline and the continuous random network model for amorphous semiconductors

2000 ◽  
Vol 638 ◽  
Author(s):  
J.K. Bording ◽  
J. Tafto
Keyword(s):  
Molecular Dynamics ◽  
Distribution Function ◽  
Molecular Dynamics Simulations ◽  
Radial Distribution Function ◽  
Radial Distribution ◽  
Volume Fraction ◽  
Random Network ◽  
Amorphous Material ◽  
Dynamics Simulations ◽  
Continuous Random Network

AbstractWe show by molecular dynamics simulations, that the radial distribution function of an amorphous material does not change significantly by introducing a considerable volume fraction of nanocrystals. The nanocrystals, embedded in a continuous random network, ensure a certain degree of medium range order in the amorphous material. Our simulations, which are on germanium, show that microcrystals smaller than 2 nm can comprise at least 20 % of the volume without significantly changing the radial distribution function from that of pure continuous random network. By increasing the size of the crystals, without altering the crystal to amorphous volume ratio, the radial distribution changes. The molecular dynamics simulations show that the nanocrystals are unchanged at low temperature. At higher temperature the mobility and critical size of the grains increase, transforming the sub-critical crystalline grains into the surrounding continuous random network matrix.

scholarly journals Estudo dos efeitos da solvatação aquosa na norepinefrina usando Dinâmica Molecular de Car-Parrinello

2020 ◽  
Author(s):  
Bruna Nery Martins ◽  
Allane C. C. Rodrigues ◽  
Arsênio P. V. Neto ◽  
Ademir J. Camargo ◽  
Heibbe C. B. de Oliveira
Keyword(s):  
Molecular Dynamics ◽  
Distribution Function ◽  
Radial Distribution Function ◽  
Radial Distribution ◽  
Solvation Shell ◽  
Biological Action ◽  
Water Molecules ◽  
Solvation Dynamics ◽  
Electronic Parameters ◽  
Ganglion Neurons

Norepinephrine, synthesized from tyrosine, is a neurotransmitter of sympathetic post-ganglion neurons. Norepinephrine regulates many critical functions which include attention, memory, learning and cardiovascular functions. This neurotransmitter has several pharmacological uses, such as adrenergic stimulants, widely used in the treatment of hypertension, cardiac surgery and in myocardial infarction. It is extremely important to study the interaction between drugs and water molecules, for a better understanding of absorption, transport and biological action. Within this context, the Car-Parrinello Molecular Dynamics, by treating the solvent explicitly, becomes ideal for the study of solvated media. In this sense, the objective of this work is to analyze the effects of aqueous solvation on the geometric and electronic parameters of norepinephrine using the Molecular Dynamics of Car-Parrinelo. The solvation dynamics was performed using the CPMD program package (version 4.1). The Radial Distribution Function of the hydrogen and oxygen atoms of the water molecules in the first solvation shell were performed for the O1, O2, O3, N7, H4, H5, H6, H8 and H9 atoms of the norepinephrine. The Radial Distribution Function analyzes indicate that most sites have a well-defined peak (N7, O1, O3, H4, H5 and H6). For the O2, H8 e H9 atoms, there are no well-defined peaks, suggesting that these sites do not interact with the atoms of the water molecules, or even the possibility of intra-molecular interactions. These criteria were considered for the next stages of this work, which are already being carried out, and they are analyzes of possible interactions of hydrogen with these sites.

Sign in / Sign up

Export Citation Format

Share Document