scholarly journals Micro/Nanoscale Study on the Effect of Aging on the Performance of Crumb Rubber Modified Asphalt

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Lan Wang ◽  
Yang Liu ◽  
Le Zhang
Keyword(s):  
Molecular Dynamics ◽  
Crumb Rubber ◽  
Dynamics Simulation ◽  
Surface Microstructure ◽  
Test Results ◽  
Force Microscopy ◽  
Modified Asphalt ◽  
Atomic Force ◽  
Before And After ◽  
Microscopic Surface

In order to explore the variation of crumb rubber modified asphalt (CR) before and after aging at the micro- and nanoscales, the molecular dynamics simulation and atomic force microscopy (AFM) asphalt microstructure scanning were carried out on CR before and after aging. The molecular dynamics energy, radial distribution function (RDF), surface microstructure image, roughness, and other test results of the CR before and after aging were compared and analyzed. The results show that the molecular dynamic energy of the CR after aging increases; the asphaltene-asphaltene RDF is decreased after aging; and the AFM surface microstructure images of asphalt before and after aging do not change significantly, but quantitative analysis by roughness theory shows that aging makes the microscopic surface of the CR more uniform and gentle. By analyzing the changes of asphalt properties before and after aging at two scales, it can be found that there is a certain relationship between the properties obtained at different scales. The reasons and mechanisms for the influence of microstructure on aging are obtained by analyzing this relationship.

Molecular Dynamics Simulation of AFM-Based Nanomachining Processes

2011 ◽  
Author(s):  
Rapeepan Promyoo ◽  
Hazim El-Mounayri ◽  
Kody Varahramyan ◽  
Ashlie Martini
Keyword(s):  
Molecular Dynamics ◽  
Friction Coefficient ◽  
Md Simulation ◽  
Computational Models ◽  
Dynamics Simulation ◽  
Radius Of Curvature ◽  
Force Microscopy ◽  
Indentation Force ◽  
Atomic Force ◽  
Development And Validation

Recently, atomic force microscopy (AFM) has been widely used for nanomachining and fabrication of micro/ nanodevices. This paper describes the development and validation of computational models for AFM-based nanomachining (nanoindentation and nanoscratching). The Molecular Dynamics (MD) technique is used to model and simulate mechanical indentation and scratching at the nanoscale in the case of gold and silicon. The simulation allows for the prediction of indentation forces and the friction force at the interface between an indenter and a substrate. The effects of tip curvature and speed on indentation force and friction coefficient are investigated. The material deformation and indentation geometry are extracted based on the final locations of atoms, which are displaced by the rigid tool. In addition to modeling, an AFM was used to conduct actual indentation at the nanoscale, and provide measurements to validate the predictions from the MD simulation. The AFM provides resolution on nanometer (lateral) and angstrom (vertical) scales. A three-sided pyramid indenter (with a radius of curvature ∼ 50 nm) is raster scanned on top of the surface and in contact with it. It can be observed from the MD simulation results that the indentation force increases as the depth of indentation increases, but decreases as the scratching speed increases. On the other hand, the friction coefficient is found to be independent of scratching speed.

Molecular Dynamics Simulation of Ice Indentation by Model Atomic Force Microscopy Tips

2015 ◽  
Vol 119 (48) ◽  
pp. 27118-27124 ◽  
Author(s):  
Julian Gelman Constantin ◽  
Marcelo A. Carignano ◽  
Horacio R. Corti ◽  
Igal Szleifer
Keyword(s):  
Molecular Dynamics ◽  
Atomic Force Microscopy ◽  
Molecular Dynamics Simulation ◽  
Dynamics Simulation ◽  
Force Microscopy ◽  
Atomic Force

Investigation of BMI-PF6 Ionic Liquid/Graphite Interface Using Frequency Modulation Atomic Force Microscopy

MRS Advances ◽  
2018 ◽  
Vol 3 (44) ◽  
pp. 2725-2733 ◽  
Author(s):  
Harshal P. Mungse ◽  
Takashi Ichii ◽  
Toru Utsunomiya ◽  
Hiroyuki Sugimura
Keyword(s):  
Molecular Dynamics ◽  
Atomic Force Microscopy ◽  
Frequency Modulation ◽  
Density Functional ◽  
Pyrolytic Graphite ◽  
Density Functional Theory Calculations ◽  
Quartz Tuning Fork ◽  
Dynamics Simulation ◽  
Force Microscopy ◽  
Atomic Force

ABSTRACTStructural analysis on interfaces between ionic liquids (ILs) and solid substrates is an important study for not only the basic fundamental aspects but also many technological processes. In the present work, we utilized frequency modulation atomic force microscopy (FM-AFM) based on a quartz tuning fork sensor to elucidate the structure of interface between 1-butyl-3-methylimidazolium hexafluorophosphate (BMI-PF6) IL and highly ordered pyrolytic graphite (HOPG) surface. It was observed that this IL form solvation layers at their interface, with ∼0.5-0.57 nm thickness of each layer. We have compared our experimental results with previously reported results from molecular dynamics simulation study, and combination of classical molecular dynamics and density functional theory calculations in order to understand the IL/HOPG interface.

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