Solutions to the differential equations of linear elasticity in continuum limit arbitrary crystal symmetry are known only for steady-state dislocations character, i.e. line defects moving at constant velocity. Troubled by singularities certain ‘critical’ velocities (typically close sound speeds), these dislocation fields thought be too idealized, and divergences usually attributed neglecting fi...

We present models of localized plastic deformation inside Persistent Slip Band channels. First, we investigate the interaction between screw dislocations as they pass one another inside channel walls in copper. The model shows the mechanisms of dislocation bowing, dipole formation and binding, and finally dipole destruction as screw dislocations pass one another. The mechanism of (dipole passin...

Manipulating the morphology of inorganic nanostructures, such as their chirality and branching structure, has been actively pursued as a means of controlling their electrical, optical and mechanical properties. Notable examples of chiral inorganic nanostructures include carbon nanotubes, gold multishell nanowires, mesoporous nanowires and helical nanowires. Branched nanostructures have also bee...

In this work, Ti–23Nb–0.7Ta–2Zr (TNTZ) and gum metal Ti–23Nb–0.7Ta–2Zr–1.2O (TNTZ-O) alloys were synthesized by cold crucible levitation melting with the objective of investigating the influence of oxygen on the deformation mechanisms. By tensile tests, electron backscatter diffraction, atomic force microscopy and transmission electron microscopy analyses, we showed that the deformation in the ...

Coracoid process fracture is easily missed in recurrent anterior shoulder dislocation. We report one such case in a 48-year-old man. Radiology revealed the Bankart lesion and the Hill-Sachs lesion only; the coracoid process fracture was discovered intra-operatively. The anatomy of the shoulder was restored by fixing the fragment to its scapular remnant with a 4-mm cannulated cancellous screw. T...

Although anterior cervical arthrodesis is an effective procedure for the treatment of cervical disorders, the method has some complications. Here, we describe this rare complication of cervical instrumentation with a literature review. A 23-year-old male patient was operated for a C6-C7 dislocation. At postoperative month 10, he presented with hemoptysis and dysphagia. Cervical roentgenograms s...

We consider a smectic-A in a capillary with surface anchoring that favors parallel alignment. If the bulk phase of the smectic is the standard twist-grain-boundary phase of chiral smectics, then there will be a critical radius below which the smectic will not have any topological defects. Above this radius a single screw dislocation in the center of the capillary will be favored. Along with sur...

We study the structure and formation energy of kinks in 1/2a<111> screw dislocations in metallic Tantalum using molecular dynamics with a first principles based many-body interatomic potential. In our study, four a/3<112> kinks are in a quadrupole arrangement in the simulation cell. We impose periodic boundary conditions in the directions perpendicular to [111] and fixed boundaries in the [111]...

BACKGROUND The defect structure of organic materials is important as it plays a major role in their crystal growth properties. It also can play a subcritical role in "hot-spot" detonation processes of energetics and one such energetic is cyclotetramethylene-tetranitramine, in the commonly used beta form (β-HMX). RESULTS The as-grown crystals grown by evaporation from acetone show prismatic, t...

Determining the atomic structure and the influence of defects on properties of low symmetry oxides have long been an engineering pursuit. Here, we focus on five thermodynamically reversible monoclinic and orthorhombic polymorphs of dicalcium silicates (Ca2SiO3)-a key cement constituent-as a model system and use atomistic simulations to unravel the interplay between the screw dislocation core en...