Search results for "DISLOCATION"

Lesión compleja del codo pediátrico: fractura de cóndilo externo asociada a luxación posteromedial de codo.

2020

espanolAntecedentes y objetivo: La fractura de condilo externo asociada a una luxacion posteromedial de codo es una entidad muy rara, de la cual existen muy pocos casos publicados. Nuestro objetivo es presentar un caso complejo tratado en nuestro centro, el diagnostico, el tratamiento elegido, y el seguimiento a las 9 semanas. Caso clinico: varon de 5 anos con una luxacion posteromedial de codo asociada a una fractura de condilo externo, diagnosticada mediante TC y tratada de forma quirurgica mediante un abordaje anterior sobre el codo, reduccion abierta y osteosintesis con agujas de Kirschner. Resultados: los resultados clinicos y radiologicos a las 9 semanas son excelentes, presentando un…

A 3D mesoscopic approach for discrete dislocation dynamics

2001

In recent years a noticeable renewed interest in modeling dislocations at the mesoscopic scale has been developed leading to significant advances in the field. This interest has arisen from a desire to link the atomistic and macroscopic length scales. In this context, we have recently developed a 3D-discrete dislocation dynamics model (DDD) based on a nodal discretization of the dislocations. We present here the basis of our DDD model and two examples of studies with single and multiple slip planes.

Impact of Superfinish Turning on Surface Integrity of Pure Copper

2011

Abstract The presented study deals with comprehension of relationships between machining cutting conditions and physical-chemical properties linked with surface integrity. A multi-physics model is presented to calculate residual stress, temperature and dislocation fields in the machined material. This model includes both thermal-mechanical, structural evolution and dynamic recristallisation approaches. The model was applied to pure copper after superfinish turning. Good agreement was found between numerical values and experimental ones. This paper also presents a work on the impact of mechanical and microstructural changes induced by machining on the electrochemical behaviour and corrosion …

Binocular motility system and temporomandibular joint internal derangement: A study in adults

2007

Abstract INTRODUCTION: Ocular convergence defects have been confirmed in adults with temporomandibular joint (TMJ) dysfunction, but few studies of the relationship of the oculomotor apparatus to TMJ disc displacement have been reported. The purpose of this study was to examine the impact of disc displacement on the oculomotor capacity of the eyes in adults. METHODS: Fifty symptomatic patients with bilateral TMJ disc displacement (13 men, 37 women; mean age, 28.84 +/- 8.22 years; range, 18-40 years) were compared with the same number of asymptomatic volunteers with normal disc position (14 men, 36 women; mean age, 29.96 +/- 5.04 years; range, 18-37 years). All subjects underwent standardized…

Hardening and formation of dislocation structures in LiF crystals irradiated with MeV–GeV ions

2002

Abstract Material modifications of LiF crystals irradiated with Au, Pb and Bi ions of MeV to GeV energy are studied by means of microindentation measurements and dislocation etching. Above a critical irradiation fluence of 10 9 ions/cm 2 , the microhardness can improve by a factor of 2 in the bulk and by more than 3 on the surface. Radiation-induced hardening follows the evolution of the energy loss along the ion path. Annealing experiments indicate that complex defect aggregates created in the tracks play a major role for the hardness change. Evidence for severe structural modifications is found when etching indentation impressions in highly irradiated crystals leading to similar pattern a…

Treatment of chronic mandibular dislocations by eminectomy: follow-up of 10 cases and literature review.

2008

Introduction: Temporomandibular joint (TMJ) dislocation is defined as an excessive forward movement of the condyle beyond the articular eminence, with complete separation of the articular surfaces and fixation in that position. Objectives: To report ten cases treated by eminectomy for chronic mandibular dislocations, to evaluate the results of these surgeries and make a critical review of the literature. Methods: The sample was obtained from the records of the Department of Oral and Maxillofacial Surgery, University of Pernambuco and comprises cases submitted to chronic mandibular dislocation treatment by eminectomy between 2002 and 2007. Pre- and postoperative assessment included a thoroug…

Atmosphere-Induced Effect in Microhardness, Dislocation Mobility and Plasticity of C60and Graphite Crystals

1997

Abstract Formation of hard, brittle and toluene-insoluble near-surface layer (∼0.3 μm) of C60 crystals under atmospheric exposure was observed. Similar atmosphere-induced effect was found for graphite crystals and might also be expected for other molecular solids. Data on ageing kinetics of C60 and graphite crystals are presented. Variation of hardness with indentation depth can be described by the microhardness model for bilayer medium with different mechanical properties. Specific feature of C60 and graphite crystals is that no size effect appears in the intrinsic microhardness and dislocation mobility characteristics in the indentation depth range of 0.6–4μm.

The liquid-solid transition of hard discs: first-order transition or Kosterlitz-Thouless-Halperin-Nelson-Young scenario?

2002

We consider the question of whether a two-dimensional hard-disc fluid has a first-order transition from the liquid state to the solid state as in the three-dimensional melting-crystallization transition or whether one has two subsequent continuous transitions, from the liquid to the hexatic phase and then to the solid phase, as proposed by Kosterlitz, Thouless, Halperin, Nelson and Young (KTHNY). Monte Carlo (MC) simulations of the fluid that study the growth of the bond orientational correlation length, and of the crystal are discussed. The emphasis is on a recent consistency test of the KTHNY renormalization group (RG) scenario, where MC simulations are used to estimate the bare elastic c…

LUSSAZIONE DISSOCIATA DEL SEMILUNARE E DELLE OSSA DEL CARPO: CASE REPORT

2014

Influence of plastic deformation on the microstructure and corrosion behaviour of Ti–10Mo–4Zr and Ti–6Al–4V alloys in the Ringer’s solution at 37°C

2015

Abstract The influence of plastic deformation on the microstructure and passivity of Ti–6Al–4V and Ti–10Mo–4Zr is studied. The content of titanium-based compounds in the passive film formed on the alloys increases under straining. In the region where necking occurs, the β-phase content drops in Ti–6Al–4V. The grain orientation spread increases with increasing strain. The quality index of EBSD maps is affected on Ti–10Mo–4Zr (dislocation structures along preferential orientations). The corrosion behaviour is investigated in the Ringer’s solution (37 °C). Results obtained in the anodic and cathodic domains are discussed considering changes described previously.