Annealing of aluminum nanoparticle and the formation of ethanol–ether binary coating layer on aluminum nanoparticle surface: A molecular dynamic study

2021 ◽  
Author(s):  
Ruochen Sun ◽  
Penghua Sui ◽  
Pingan Liu ◽  
Lei Wang ◽  
Hui Qi ◽  
...  
Keyword(s):  
Potential Energy ◽  
Cooling Rate ◽  
Molecular Dynamic ◽  
Coating Layer ◽  
Particle Surface ◽  
Mean Square Displacement ◽  
Melting Process ◽  
Critical Research ◽  
Metal Fuel ◽  
Main Component

Aluminum (Al) nanoparticle (ANP), as a metal fuel agent, has excellent combustion rate and energy density. However, several critical research gaps of ANP still exist. This study is focused on the annealing properties of ANP and its coating performances under the mixture of ethanol and ether molecules. According to those obtained molecular dynamic (MD) simulation results, the microstructure of ANP in the annealing process and the formation of ethanol–ether binary coating are discussed in this paper. During the melting process, the melting point of ANP could be analyzed by the inflection point of its atomic potential energy and the mean square displacement, then the accuracy of EAM force field could be verified. Because surface atoms have lower potential energy than inner atoms, it seems that the melting of ANP started from the particle surface and diffuses from surface to the core. When the melted Al cluster is solidified until 300 K, the microstructure of the crystallized particle is largely affected by the cooling rate. If the cooling rate if too fast, it is not enough for the Al cluster to recrystallize, which is called as the “freezing effect” for ANP. Next, the binary “competitive adsorption” behavior of ethanol and ether on the surface of ANP was simulated according to different ethanol–ether molecular ratios. Analyses of ethanol–ether binary coating layer show that the main component of binary coating is ethanol, but not ether. This competitive superiority of ethanol is caused by its own adsorption mechanism and molecular migration in this mixture of ethanol and ether.

Solving the Problem of Silicon Dioxide Melting Based on Deviation Model

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Yuhan Sun
Keyword(s):  
Silicon Dioxide ◽  
Blast Furnace Slag ◽  
Melting Process ◽  
Melting Rate ◽  
Dissolution Behavior ◽  
Characteristic Parameters ◽  
Contour Feature ◽  
Time Periods ◽  
Main Component ◽  
Furnace Slag

Abstract: In order to reveal the dissolution behavior of iron tailings in blast furnace slag, we studied the main component of silica in iron tailings. First, edge contour features need to be established to represent the melting process of silica. We choose shape, perimeter, area and generalized radius as objects. By independently analyzing the influence of these four indexes on the melting rate, the area and shape were selected as the characteristic parameters of the edge contour of the silica particles. Then, the actual melting rate of the silica is estimated by the edge contour feature index. Finally, we can calculate the melting rate of the first second of three time periods of 0.00010312mm3/s，0.0002399mm3/s，0.0000538mm3/s.

Microstructure and Hardness of Gray Cast Iron as a Product of Solidification in Permanent Mold

2020 ◽  
Vol 991 ◽  
pp. 37-43
Author(s):  
Agus Yulianto ◽  
Rudy Soenoko ◽  
Wahyono Suprapto ◽  
As’ad Sonief ◽  
Agung Setyo Darmawan ◽  
...  
Keyword(s):  
Cast Iron ◽  
Cooling Rate ◽  
Induction Furnace ◽  
Gray Cast Iron ◽  
Casting Process ◽  
Melting Process ◽  
Gray Cast ◽  
Outer Side ◽  
Permanent Mold ◽  
Test Results

Molds of metal are widely used in the casting process. The cooling rate in solidification of castings product with metal molds on the outer side and inner side is different. Therefore, sizes and types of phase will be also different. This study aims to investigate the microstructure andhardness of gray cast iron. To realize this research, the gray cast iron melting process was carried out in an induction furnace. Melted gray cast iron was poured into a Ferro Casting Ductile mold that has been through a preheating process at a temperature of 300 o C. The gray cast iron is then tested for composition, microstructure and hardness. The test results show that the part containing morecementite phase will be harder.

A Comparison of Kinetostatic and Multibody Dynamics Models for Simulating Protein Structures

2007 ◽  
Author(s):  
Hai-Jun Su ◽  
Jesse Parker ◽  
Kazem Kazerounian ◽  
Horea Ilies
Keyword(s):  
Potential Energy ◽  
Molecular Dynamic Simulation ◽  
Molecular Dynamic ◽  
Dynamic Simulation ◽  
Multibody Dynamics ◽  
Energy State ◽  
Protein Structures ◽  
Rigid Bodies ◽  
Static Compliance ◽  
Protein Molecules

This paper presents an initial comparison of two approaches to energy minimization of protein molecules, namely the Molecular Dynamic Simulation and the Kineto-Static Compliance Method. Both methods are well established and are promising contenders to the seemingly insurmountable task of global optimization in the protein molecules potential energy terrain. The Molecular Dynamic Simulation takes the form of Constrained Multibody Dynamics of interconnected rigid bodies, as implemented at the Virtual Reality Application Center from Iowa State University. The Kineto-Static Compliance Method is implemented in the Protofold Computer package developed in the Mechanical Engineering Department at the University of Connecticut. The simulation results of both methods are compared through the trajectory of potential energy, the Root Mean Square Deviation (RMSD) of the alpha carbons, as well as based on visual observations. The preliminary results indicate that both techniques are very effective in converging the protein structure to a state with significantly less potential energy. At present, the converged solutions for the two methods are, however, different from each other and are very likely different from the global minimum potential energy state.

Molecular Dynamics Simulation of Two-Phase Structures of Copper Formed by Laser Grooving

2014 ◽  
Vol 597 ◽  
pp. 242-248
Author(s):  
Peng Wen ◽  
Gang Tao ◽  
Pei Jie Zhou
Keyword(s):  
Molecular Dynamics ◽  
Cooling Rate ◽  
Pair Correlation ◽  
Critical Role ◽  
Mean Square Displacement ◽  
Solidification Process ◽  
Structural Features ◽  
Dynamics Simulation ◽  
Two Phase ◽  
Phase Structures

It is a concerned problem that what influences of cooling rate on evolution of microstructures of the treated and untreated Cu are during solidification process after Cu’s being melted by laser grooving. Based on the embedded-atom method, molecular dynamics simulations have been performed on the cooling processes of liquid metal Cu by using crystal-liquid configuration method at six different cooling rates. Through the two-phase structural features, pair correlation function, average atomic energy and mean square displacement analysis, it is found that the cooling rate plays a critical role on the solidification process to the liquid Cu. The liquid Cu becomes its crystalline state during relatively low cooling rate, while the glass transition of the liquid Cu is performed with the relatively high cooling rate. The solidification process of the liquid Cu has effect on the solid crystal Cu and leads to form the indented interface between two-phase structures.

Improved Ni and Cd Rejection in Cellulose Acetate Mixed Matrix Membranes Coated with PVA/Fe3O4

2018 ◽  
Vol 43 (3) ◽  
pp. 237-243
Author(s):  
Mohammad Nouri ◽  
Azam Marjani ◽  
Majid Tajdari ◽  
Farhad Heidary ◽  
Mahmoud Salimi
Keyword(s):  
Cellulose Acetate ◽  
Metal Ion ◽  
Active Sites ◽  
Coating Layer ◽  
Mean Square Displacement ◽  
Mixed Matrix Membranes ◽  
Mixed Matrix ◽  
Ion Rejection ◽  
Substrate Layer ◽  
Matrix Membranes

AbstractA series of polyvinyl alcohol (PVA)/Fe3O4-coated cellulose acetate mixed matrix membranes were analyzed for Cd and Ni removal, both experimentally and theoretically. The effect of the coating layer on the metal ion rejection performance was investigated using molecular modeling approaches. Lower energy requirements for the detachment of ions from the coating layer were calculated. Our results imply that the coating layer interacts with metal ions to a much lower extent than the substrate layer does. Smaller mean square displacement data were calculated in the coating layer than in the substrate layer, which indicates a lower diffusivity of ions in the coating layer. This in turn shows the coating layer efficiently prevents ion transfer and provides higher retention/rejection. We conclude that applying a coating layer with lower Fe3O4 content would enhance the ion rejection performance of cellulose acetate mixed matrix membranes. The addition of Fe3O4 particles increases the number of active sites and the surface area, while a high content of these particles must be avoided as they may surround functional groups of polymer chains and also increase the porosity, which decreases the rejection performance of membranes.

Cellulose Acetate Mixed Matrix Membranes Coated with PEG/TiO2 for Removal of Pb(II) Ions from Aqueous Solutions: Combined Experimental and Quantum Chemical Modeling Investigation

2019 ◽  
Vol 44 (2) ◽  
pp. 193-202 ◽  
Author(s):  
Mohammad Nouri ◽  
Azam Marjani ◽  
Majid Tajdari
Keyword(s):  
Monte Carlo ◽  
Aqueous Solutions ◽  
Metal Ions ◽  
Cellulose Acetate ◽  
Quantum Chemical ◽  
Coating Layer ◽  
Mean Square Displacement ◽  
Mean Square ◽  
Substrate Layer ◽  
The Mean

Abstract Porous cellulose acetate (CA) flat sheet membranes containing 8-hydroxyquinoline (as complexing agent) coated with polyethylene glycol (PEG)/TiO2 nanocomposite solution were fabricated. For the removal of Pb(II) ions from aqueous solutions, retention data were measured experimentally. To analyze and examine the practical effect of the coating layer on the rejection of metal ions, a quantum chemical calculation and modeling approach was employed. The simulations were conducted on (1) coating layers and (2) a substrate layer. In each simulation, (i) the lowest energy sites on layers were searched against their affinity for metal ions by performing Metropolis Monte Carlo and configurational bias Monte Carlo search of the ion–membrane configurational space according to a simulated annealing schedule, and (ii) the evolution of ions in each layer was examined by the mean square displacement through molecular dynamics simulations. The coating layer showed a potential to significantly interact with ions with higher energy requirements for the detachment from the coating layer in comparison to the substrate layer. This suggested that the metal ions would increasingly accumulate on the coating layer and its lateral surface. The mean square displacement data showed smaller values in the coating layer rather than in the substrate layer, indicating that the coating layer efficiently inhibits ion transfer and provides higher retention values. Thus, greater metal ion retention is expected on and around the coating layer. This is in agreement with the determined attachment and detachment energies. Finally, acceptable agreement was found between numerical and experimental results.

Processing of TiC-CNT Hybrid Composite Coating on Low Alloy Steel Using TIG Torch Technique

2013 ◽  
Vol 378 ◽  
pp. 259-264 ◽  
Author(s):  
M.A. Maleque ◽  
Kamilu Adeyemi Bello ◽  
A.N. M. Idriss ◽  
S. Mirdha
Keyword(s):  
Alloy Steel ◽  
Cross Sections ◽  
Powder Mixture ◽  
Vickers Microhardness ◽  
Coating Layer ◽  
Melting Process ◽  
Low Alloy Steel ◽  
Arc Melting ◽  
Operating Current ◽  
Coated Surface

In the present study, a surface layer of TiC-CNT hybrid compositecoating has been developed on low alloy steel (LAS) by using powder preplacement and tungsten inert gas (TIG) torch melting techniques.The weighed powder mixture with the content of 1.0 mg per millimeter square area and containing TiC-4wt. % CNT particles was preplaced on LAS surfaces using a suitable binder and then melted under the TIG arc with an operating current of 100 A and energy input of 1440 J/mm. The microstructural and microhardness characteristics of the processed composites coating were analyzed using SEM, EDXand Vickers microhardness testers. Under the melting condition used in this investigation, the arc completely dissolved the composite powder mixture that resolidifiedinto a melt track with radial marks and smooth surfaces. Themelt cross sections were hemispherical in shape and produced 1 mm deep hard coating layer which were free from porosity and cracks. SEM micrographs TiC-CNT hybrid coated surface glazed at 100A consists of fineprecipitated TiC in form globular and cubic dendrites and this is the reason for hardness increment to an average of three times greater than that of substrate value. The result obtained indicated that TIG arc melting process is applicable to generate resolidified layer of precipitated TiC microstructure with uniformly distribution in the coating region.

Probing Potential Energy Surfaces in Confined Systems: Behavior of Mean-Square Displacement in Zeolites

1994 ◽  
Vol 98 (37) ◽  
pp. 9354-9359 ◽  
Author(s):  
M. Ghosh ◽  
G. Ananthakrishna ◽  
S. Yashonath ◽  
P. Demontis ◽  
G. Suffritti
Keyword(s):  
Potential Energy ◽  
Potential Energy Surfaces ◽  
Mean Square Displacement ◽  
Mean Square ◽  
Confined Systems ◽  
Energy Surfaces
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