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 20 of 536 for “"Atomistic"”.
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Atomistic Study of Grain Boundary Sliding
… (NEB) and Transition State Theory (TST) to do atomistic calculation. The observations in atomistic calculations, that the sliding rate is lower than the previous atomistic calculations by several orders of magnitude, has given a way to bridge the gap between experiments and simulations on GBS. …
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Stress effects on atomistic kinetic transitions
In this thesis, I studied how the full tensorial stress state applied to a kinetic transition impacts the activation enthalpy. To this end, the activation energy, scalar activation volume, and tensorial activation volume were studied for several kinetic transition types. This computational study …
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Atomistic studies on irradiation damage in iron
Two topics involving irradiation damage in alpha-iron have been considered. First, damage cascades representative of those that would be induced by radiation have been simulated using molecular dynamics (MD). The number and type of defects produced are compared for pure iron and iron with a small …
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Data-driven PSP linkages for atomistic datasets
… “process-structure-property” (PSP) linkages for atomistic simulations presents a powerful route to convert atomistic simulation data into actionable knowledge. Here, a framework is presented for quantifying structure from these simulations in full- and reduced-dimensional form, and a series of …
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Atomistic simulations of semiconductor and metallic nanoparticles
Semiconductor and metallic nanoparticles have recently become an attractive area of intensive research due to their unique and diverse properties, that differ significantly from bulk materials. With a wide range of applications and potential uses in nanoelectronics, catalysis, medicine, chemistry …
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Atomistic and mesoscale modeling of dislocation mobility
… core and a long-range stress field, linking atomistic and meso scales is often the most challenging step in studying its dynamics. This Thesis presents theories and simulations of dislocations in Si and BCC transition metals, with emphasis on the atomistic-mesoscale coupling. Contributions …
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Hybrid atomistic-continuum formulations for gaseous flows
Hybrid atomistic-continuum formulations allow the simulation of complex hydrodynamic phenomena at the nano and micro scales without the prohibitive cost of a fully atomistic approach. This is achieved through a domain decomposition strategy whereby the atomistic model is limited to regions of the …
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Applicability Of Continuum Fracture Mechanics In Atomistic Systems
… However, due to the discrete nature of the atomistic structures without stress singularity, there might be discrepancy between the failure prediction and the reality of nanostructured materials. Defining the local atomistic stress with convergence within one lattice ensures the near-tip …
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Atomistic simulations of deformation in Metallic Nanolayered Composites
… with increasing the layer thickness. A novel atomistic-informed interface-dislocation dynamics (I-DD) model has been developed to study Metal-Ceramic Nanolayered Composites (MCNCs) based on the key deformation process and microstructure features revealed by MD simulations. The I-DD predicted …
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Graphene under strain. A combined continuum-atomistic approach
By combining continuum elasticity theory and atomistic simulations, we provide a picture of the elastic behavior of graphene, which was addressed as a two-dimensional crystal membrane. Thus, the constitutive nonlinear stress-strain relations for graphene, as well as its hydrogenated conformers, …
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Atomistic modelling of precipitation in Ni-base superalloys
… quenching and annealing. For this we use the atomistic simulation methods of molecular dynamics (MD) and density functional theory (DFT). In the first part of this work we develop robust Bayesian classifiers to identify the $\gamma^{\prime}$ phase in large scale simulation boxes at high …
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Interfaces in carbon materials : experiment and atomistic simulation
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1995.
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Investigating intergranular fracture in nickel via atomistic simulations
… the critical energy release rate Gc from atomistic simulations, we also compared the toughness of fractures by these three mechanisms. In the course of investigating intergranular fracture, we discovered a new mechanism for crack healing in a 2D model. This mechanism relies on the …
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Atomistic simulation of dislocation core structures in B2 NiAl
… dislocations in B2 NiAI has been conducted using atomistic simulations with an embedded atom method (EAM) potential. New flexible boundary conditions and a new method of graphic representation of dislocation core structure have been employed. The main findings are the following: Core structures: …
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Results on the interaction between atomistic and continuum models
In this thesis, we develop continuum notions for atomistic systems which play an important role in developing accurate constitutive relations for continuum models, and robust multiscale methods for studying systems with multiple length and time scales. We use a unified framework to study the …
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Atomistic and Coarse-Grained Investigation of Membrane-Protein Interactions
… to elucidate such interactions. First, we used atomistic studies to investigate in-creased binding affinity of a membrane-remodeling protein (epsin) to membranes subjectedto high tension. We performed umbrella sampling calculations to provide the first quantita-tive evidence that tension …
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Atomistic modeling of crack tip behavior in ductile materials
… period, reconciling reports of crack growth in atomistic simulations at loading amplitudes below experimental crack growth thresholds. It is also observed that sustained crack growth in vacuum only occurs when emitted dislocations return to the crack tip on a slip plane behind its original one, …
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Atomistic model of void nucleation and growth during electromigration
… To help gain a better understanding of the atomistic processes involved in void formation under electromigration conditions we have used the Embedded Atom Method (BAM) to determine the structure and formation energies of small voids (up to 20 vacancies) in aluminum and copper both in bulk …
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