Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 18 of 18 for “"Atomistic Models"”.
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Mechanics of Carbon Nanotubes: A Continuum Theory Incorporating Interatomic Potentials
… is in good agreement with experimental and atomistic findings. It is also found that the critical strain at which instability occurs when a carbon nanotube is subject to tension is agreeable to that predicted by atomistic models.
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Data-driven models of water and methane
In the field of materials modelling, traditional atomistic models seldom achieve high accuracy and speed at the same time. Recent developments using high-dimensional fits to approximate the quantum chemical potential energy surface (PES) have overcome this problem. This thesis presents such models …
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Continuum models of deformation mechanisms in nanocrystalline metals
… behavior of grain boundaries. In agreement with atomistic models and experiments, tensile test simulations using the numerical model predict the inverse Hall-Petch effect, i.e. a dependence of the yield stress on the inverse square root of the grain size with a negative slope. In addition, the …
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Nanocontacts controlled atom-by-atom in an ion-crystal friction emulator
… and energy dissipation. To test long-standing atomistic models of friction processes at the nanoscale, we implemented a synthetic nanofriction interface between a laser-cooled Coulomb crystal of individually addressable ions as the moving object and a periodic light-field potential as the …
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Molecular Dynamics and X-ray Powder Diffraction Simulations: Investigation of nano-polycrystalline microstructure at the atomic scale coupling local structure configurations and X-ray powder Diffraction techniques
Atomistic simulations based on Molecular Dynamics (MD) were used to model the lattice distortions in metallic nano-polycrystalline microstructures, with the purpose of supporting the analysis of the X-ray powder diffraction patterns with a better, atomic level understanding of the studied system. …
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First principles simulation of cement for nuclear waste disposal
… hydrate we show that the results of both models agree that the strontium decay chain is immobilised within the intralayer region of cements. The techniques outlined present a simple framework for atomistic models of cement-like minerals to study the storage of nuclear wastes within cement.
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Multiscale modeling of clay-water systems
… However, existing macro-scale continuum models have no length scale to describe the evolution of the clay microstructure and its role in affecting macroscopic properties. This research proposes a bottom-up multiscale modeling approach to understand the physics underlying macroscopic clay …
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Theoretical Design of Molecular Nanostructures for Exciton Control
… morphology. This thesis employs mathematical and atomistic models to contribute key physical insights into the interdependencies between chromophore spatial organization and exciton dynamics, shaped by inter-chromophore couplings and interactions with the thermal bath. In the first part, a Frenkel …
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Multiscale Modeling of the Deformation of Semi-Crystalline Polymers
… of macroscopic properties directly from atomistic computations. As a result, computational tools and methods to bridge the length and time scale gaps between atomistic and continuum models are required. In this research, an internal state variable continuum model has been developed whose …
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Computational modelling of polymer network formation
… method, benchmarked against a fine-grained, atomistic model that was constructed using Reactive Molecular Dynamics (RMD). A modified version of RMD was implemented using a non-reactive force field, and used it to estimate the physical properties of a 3D printing thermosetting-thermoplastic …
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Molecular Dynamics Simulations for the Study of Biophysical Processes on Biological Membranes
… the complexity of the membrane matrix using atomistic models. Here, we discuss three specific biological processes that are associated with biological membranes: 1) membrane stabilization, 2) membrane phase behavior, and 3) fatty acid-induced toxicity in cell membranes. For membrane …
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A Computational Framework for Long-Term Atomistic Analysis of Solute Diffusion in Nanomaterials
… forces for kinetics. Compared to previous atomistic models, e.g., accelerated Molecular Dynamics and on-the-fly kinetic Monte Carlo, DMD allows the use of larger time-step sizes and hence has a larger simulation time window for mass transport problems. This dissertation focuses on the …
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Structure and Mechanical Properties of Cement and Intermetallic Compounds via ab-initio Simulations
… be used as a basis to validate existing C-S-H models and to build improved ones. This work goes further and validates the recently proposed models (2014) for C-S-H (I) phase on the same basis of proposed electronic structure parameters. Then the respective Calcium aluminosilicate hydrates …
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Examining the role of water and hydrophobicity in folding, aggregation, and allostery
… depend on the mathematical model employed. Atomistic models provide the most detail for a simulation, but due to the computational costs required are not typically used to study phenomena which require large systems and time scales greater than several μs. Coarse-grained (CG) models reduce …
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Accounting for temperature and local structure in atomistic calculations of interface free energies in metals
… free energies for solid/liquid interfaces using atomistic models. I demonstrate these methods on CuNbHe and AlGa models due to the importance of location- and temperature-dependence of interface energies in these systems. My analysis sheds light on interfacial He precipitation in CuNb composites …
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Atomic structures and properties of oxide interfaces
… in interface studies is the lack of definitive atomistic models, yet they are essential input for any calculations. Here, this problem is tackled by ab initio random structure searching (AIRSS), or more broadly speaking, random structure searching (RSS). The initial work studies the interfaces …
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Transferable Coarse-Grained Models: From Hydrocarbons to Polymers, and Backmapped by Machine Learning
… to graphene and metals. In CG MD simulations, atomistic groups are represented by beads, which reduces the degrees of freedom in the systems and allows larger timesteps. Thus, large time and length scales could be achieved in CG MD simulations with inexpensive computational cost. The …
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Towards data-driven inverse design for materials and structures
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-02-04 without embargo terms