Several \\~ell-sllbstantiated examples of both two-dimensional nucleation (ZDN) and multiple scre\v dislocation growth (MSDG) are described. The relations derived in Part I permit quantitative estimates of the edge energy parameter b in some cases, and confirm former interpretations of growth behaviour, except in the two instances now specified. The use of edge rather than surface energy as the...

We theoretically show that an astigmatic transformation of nth-order edge dislocation (a zero-intensity straight line) produces n optical elliptical vortices (spiral dislocations) with unit topological charge at the double focal distance from cylindrical lens, located on a line perpendicular to dislocation, points whose coordinates are roots Hermite polynomial. The orbital angular momentum is p...

This thesis consists of two parts. The first part explores a 2-d edge dislocation model to demonstrate characteristics of Field Dislocation Mechanics (FDM) in modeling single and collective behavior of individual dislocations. The second work explores the possibility of modelling adiabatic shear bands propagation within the timespace averaged framework of Mesoscopic Field Dislocation Mechanics ...

The mechanisms of deformation under a nanoindentation in tantalum, chosen as a model body-centered cubic (bcc) metal, are identified and quantified. Molecular dynamics (MD) simulations and indentation experiments are conducted for [100], [110] and [111] normals to surface orientations. The simulated plastic deformation proceeds by the formation of nanotwins, which rapidly evolve into shear disl...

We report in situ electron microscopy observations of dislocation dissociation and annihilation processes in individual nanometer-sized carbon onions. Essential for these processes is the counterintuitive motion of the 1 2 < 0001 > edge from the outer surface to the inner region, which cross-links or unlinks a large number of shells. The correlation with atomistic simulations and analysis of th...

We report what is believed to be the first detailed experimental observation of the dynamic inversion of the topological charge of an optical vortex under free-space propagation. The vortex self-transformation occurs through continuous deformation of the noncanonical strength of the corresponding screw wave front dislocation, and is mediated by the occurrence of an extremely sharp turn in a Ber...