Computer Studies on free and Confined Amorphous Polymer Films

1996 ◽  
Vol 464 ◽  
Author(s):  
G. Pätzold ◽  
D.W. Heermann ◽  
A. Linke ◽  
T. Hapke
Keyword(s):  
Molecular Dynamics ◽  
Preparation Method ◽  
Amorphous Polymer ◽  
Surface Preparation ◽  
Van Der Waals Interactions ◽  
Pressure Oscillations ◽  
Free Surfaces ◽  
Polymer Systems ◽  
Pressure Profiles ◽  
Computer Studies

ABSTRACTWe study surface effects in amorphous polymer systems by means of computer simulation. In the framework of molecular dynamics, we present two different methods to prepare such surfaces. Free surfaces are stabilized solely by van-der-Waals interactions, whereas confined surfaces emerge in the presence of repelling plates. The buildup of density and pressure profiles from zero to their bulk values depends on the surface preparation method. In the case of confined surfaces, we find density and pressure oscillations next to the repelling plates. For free surfaces, we attest chain-end enrichment and present a comparison between density profile and particle coordination number.

scholarly journals Effect of Substrate Roughness on Oxidation Resistance of an Aluminized Ni-Base Superalloy

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 782 ◽  
Author(s):  
Wojciech J. Nowak ◽  
Kamil Ochał ◽  
Patrycja Wierzba ◽  
Kamil Gancarczyk ◽  
Bartek Wierzba
Keyword(s):  
Oxidation Resistance ◽  
Diffusion Processes ◽  
Preparation Method ◽  
Substrate Surface ◽  
Surface Preparation ◽  
Chemical Vapor ◽  
Substrate Roughness ◽  
Grit Blasting ◽  
Alumina Particles ◽  
Base Superalloy

In the present work, it is shown that the surface preparation method used on two Ni-based superalloys prior to aluminizing chemical vapor deposition (CVD) is one of the most important factors determining the oxidation resistance of aluminized Ni-based superalloys. It was found that grit-blasting the substrate surface negatively affects the oxidation resistance of the aluminized coatings. For grit-blasted and aluminized IN 625, a thicker outer NiAl coating was formed compared to that of IN 738. In contrast, no effect on NiAl coating thickness was found for grit-blasted and aluminized IN 738. However, a thicker interdiffusion zone (IDZ) was observed. It was shown that the systems with grit-blasted surfaces reveal worse oxidation resistance during thermal shock tests—namely, a higher mass loss was observed for both grit-blasted and aluminized alloys, as compared to ground and aluminized alloys. A possible reason for this effect of remaining alumina particles originating from surface grit-blasting on the diffusion processes and stress distribution at the coating/substrate is proposed.

Influence of surface preparation method on retained austenite quantification

2020 ◽  
Vol 24 ◽  
pp. 101226
Author(s):  
L.A. Pinto ◽  
D. Pérez Escobar ◽  
O.S.H. Santos ◽  
N.I.A. Lopes ◽  
J.R.G. Carneiro ◽  
...  
Keyword(s):  
Retained Austenite ◽  
Preparation Method ◽  
Surface Preparation

Structural Response of Metal Crystallite with BCC Lattice on Atomic Level under Nanoindentation

2013 ◽  
Vol 592-593 ◽  
pp. 55-58 ◽  
Author(s):  
Dmitrij Sergeevich Kryzhevich ◽  
Aleksandr Vyacheslavovich Korhuganov ◽  
Konstantin Petrovich Zolnikov ◽  
Sergei Grigorievich Psakhye
Keyword(s):  
Molecular Dynamics ◽  
Structural Response ◽  
Data Interpretation ◽  
High Accuracy ◽  
Atomic Level ◽  
Structural Defects ◽  
Embedded Atom Method ◽  
Free Surfaces ◽  
Embedded Atom ◽  
Bcc Lattice

Molecular dynamics investigation of metal crystallite with bcc lattice under nanoindentation was carried out. Potentials of interatomic interactions were calculated on the base of the approximation of the embedded atom method. The potentials chosen make it possible to describe with a high accuracy the elastic and surface properties of the simulated metal and energy parameters of defects, which is important for solution of the task posed in the work. For clarity and simpler indentation data interpretation, an extended cylindrical indenter was used in the investigation and loading was realized by its lateral surface. The simulated crystallite had a parallelepiped shape. The loaded plane of crystallite was modeled as a free surface while the positions of atoms in the opposite plane of crystallite were fixed along the indentation direction. Other planes of crystallite were simulated as free surfaces. The indenter velocity varied from 5 to 25 m/s in different calculations. The loading of the model crystallite was realized at 300 K. Influence of interfaces (free surfaces and grain boundaries) on peculiarities of plastic deformation nucleation and interactions of generated structural defects with interfaces in simulated crystallite under nanoindentation were investigated.

Molecular dynamics simulation on the mechanical properties of natural-rubber-graft-rigid-polymer/rigid-polymer systems

2018 ◽  
Vol 20 (12) ◽  
pp. 8228-8240 ◽  
Author(s):  
Meng Wei ◽  
Pengxiang Xu ◽  
Yizhong Yuan ◽  
Xiaohui Tian ◽  
Jinyu Sun ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Natural Rubber ◽  
Dynamics Simulation ◽  
Polymer Systems ◽  
Rigid Polymer

Explanation of the experimental phenomenon of modified natural-rubber using a MD method.

A new surface preparation method for microscopic digital image correlation applications

2019 ◽  
Vol 12 ◽  
pp. 377-382
Author(s):  
Edgar Peretzki ◽  
Martin Stockmann ◽  
Thomas Lehmann ◽  
Jörn Ihlemann
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Preparation Method ◽  
Surface Preparation ◽  
Image Correlation

scholarly journals Effect of Lysyllysine on non-covalent hybridization of single walled carbon nanotube by single-stranded DNA homodimer: in silico approach

2019 ◽  
Vol 9 (4) ◽  
pp. 315-321
Author(s):  
Fateme Bagherolhashemi ◽  
Mohammad Reza Bozorgmehr ◽  
Mohammad Momen-Heravi
Keyword(s):  
Molecular Dynamics ◽  
Carbon Nanotube ◽  
Electrostatic Interactions ◽  
Membered Ring ◽  
Binding Energies ◽  
Van Der Waals Interactions ◽  
Dynamics Simulation ◽  
Quantum Calculations ◽  
Single Walled Carbon Nanotube ◽  
Sensor Properties

Abstract In this work, the interactions between adenine–adenine di-nucleotide (DA2N) and carbon nanotube (CNT) in the presence of Lysyllysine (LL) was studied by the molecular dynamics simulation. Different carbon nanotubes including (5.5), (6.6) and (7.7) were used to investigate the effect of CNT type. The binding energies were calculated using the molecular mechanics-Poisson Bolzmann surface area method. The results showed that the contribution of the van der Waals interactions between DA2N and CNT was greater than that of the electrostatic interactions. The LL significantly enhanced the electrostatic interactions between the DA2N and CNT (6.6). The quantum calculations revealed that the sensor properties of the DA2N were not significantly affected by the CNT and LL. However, the five-membered ring of adenine played a more important role in the sensing properties of the DA2N. The obtained results are consistent with the previous experimental observations that can help to understand the molecular mechanism of the interaction of DA2N with CNT. Graphic abstract

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