Development of the distributed dislocation dipole technique for the analysis of closure of complex fractures involving kinks and branches

2018 ◽  
Vol 69 ◽  
pp. 168-178
Author(s):  
M.W. Tofique ◽  
N. Hallbäck
Keyword(s):  
Dislocation Dipole ◽  
Complex Fractures ◽  
Distributed Dislocation

A New Defect in Polyethylene Single Crystals

1973 ◽  
Vol 31 ◽  
pp. 70-71
Author(s):  
E. L. Thomas ◽  
S. L. Sass
Keyword(s):  
Single Crystals ◽  
Screw Dislocation ◽  
Small Distance ◽  
Dipole Model ◽  
Dislocation Dipole ◽  
Chain Folding ◽  
Black And White ◽  
Polymer Crystal ◽  
Different Types

In polyethylene single crystals pairs of black and white lines spaced 700-3,000Å apart, parallel to the [100] and [010] directions, have been identified as microsector boundaries. A microsector is formed when the plane of chain folding changes over a small distance within a polymer crystal. In order for the different types of folds to accommodate at the boundary between the 2 fold domains, a staggering along the chain direction and a rotation of the chains in the plane of the boundary occurs. The black-white contrast from a microsector boundary can be explained in terms of these chain rotations. We demonstrate that microsectors can terminate within the crystal and interpret the observed terminal strain contrast in terms of a screw dislocation dipole model.

Formation of Persistent Slip Band in Fatigued Copper Single Crystals

1982 ◽  
Vol 40 ◽  
pp. 470-471
Author(s):  
N. Y. Jin
Keyword(s):  
Volume Fraction ◽  
Fatigue Cracks ◽  
Wall Structure ◽  
Matrix Structure ◽  
Dislocation Dipole ◽  
Slip Bands ◽  
Persistent Slip Bands ◽  
The Matrix ◽  
Hard Shell ◽  
Copper Single Crystals

Localised plastic deformation in Persistent Slip Bands(PSBs) is a characteristic feature of fatigue in many materials. The dislocation structure in the PSBs contains regularly spaced dislocation dipole walls occupying a volume fraction of around 10%. The remainder of the specimen, the inactive "matrix", contains dislocation veins at a volume fraction of 50% or more. Walls and veins are both separated by regions in which the dislocation density is lower by some orders of magnitude. Since the PSBs offer favorable sites for the initiation of fatigue cracks, the formation of the PSB wall structure is of great interest. Winter has proposed that PSBs form as the result of a transformation of the matrix structure to a regular wall structure, and that the instability occurs among the broad dipoles near the center of a vein rather than in the hard shell surounding the vein as argued by Kulmann-Wilsdorf.

Aesthetic approaches in complex fractures of the zygomatic bone

2019 ◽  
Vol 68 (1) ◽  
Author(s):  
Pedro H. da Hora Sales ◽  
Raquel B. Vasconcelos ◽  
Raíssa F. Papaléo ◽  
Leonardo de Freitas Silva ◽  
Daniel F. da Silveira Santos
Keyword(s):  
Zygomatic Bone ◽  
Complex Fractures

Evaluation of the Effects of Exogenous Melatonin in Zygomatic Complex Fractures

2021 ◽  
Author(s):  
Emerson Filipe de Carvalho Nogueira ◽  
Vanessa de Carvalho Melo ◽  
Ivson Souza Catunda ◽  
Jéssica Caroline Afonso Ferreira ◽  
Suzana Célia de Aguiar Soares Carneiro ◽  
...  
Keyword(s):  
Exogenous Melatonin ◽  
Complex Fractures
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