Dissociation and core structure of 〈110〉 screw dislocations in L12ordered alloys II. Effects of an applied shear stress

1982 ◽  
Vol 45 (5) ◽  
pp. 883-894 ◽  
Author(s):  
V. Paidar ◽  
M. Yamaguchi ◽  
D. P. Pope ◽  
V. Vitek
Keyword(s):  
Shear Stress ◽  
Core Structure ◽  
Screw Dislocations ◽  
Applied Shear Stress

Interaction Between Lattice Dislocations and Grain Boundaries In Ordered Compounds

1990 ◽  
Vol 213 ◽  
Author(s):  
B.J. Pestman ◽  
J. Th. M. De Hosson ◽  
V. Vitek ◽  
F.W. Schapink
Keyword(s):  
Shear Stress ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Partial Dislocation ◽  
Atomistic Simulations ◽  
Many Body ◽  
Shockley Partial Dislocation ◽  
Screw Dislocations ◽  
Applied Shear Stress ◽  
Tilt Boundaries

ABSTRACTThe interaction of 1/2<1 1 0> screw dislocations with symmetric [1 1 0] tilt boundaries was investigated by atomistic simulations using many-body potentials representing ordered compounds. The calculations were performed with and without an applied shear stress. The observations were: absorption into the grain boundary, attraction of a lattice Shockley partial dislocation towards the grain boundary and transmission through the grain boundary under the influence of a shear stress. It was found that the interaction in ordered compounds shows similarities to the interaction in fcc.

Dislocation—like Defects in an Amorphous Lennard—jones Solid

1986 ◽  
Vol 82 ◽  
Author(s):  
L. T. Shi ◽  
P. Chaudhari
Keyword(s):  
Computer Simulation ◽  
Shear Stress ◽  
Screw Dislocations ◽  
Lennard Jones ◽  
Simulation Techniques ◽  
Applied Shear Stress ◽  
Computer Simulation Techniques

ABSTRACTIt has been found, using computer simulation techniques, that both edge and screw dislocations can be stably introduced into an amorphous Lennard-Jones solid, and can be moved through the model under an applied shear stress.

Influence of Shear Stress on Screw Dislocations in a Model Sodium Lattice

1971 ◽  
Vol 49 (16) ◽  
pp. 2160-2180 ◽  
Author(s):  
Z. S. Basinski ◽  
M. S. Duesbery ◽  
Roger Taylor
Keyword(s):  
Shear Stress ◽  
First Principles ◽  
Dislocation Core ◽  
The Body ◽  
Peierls Stress ◽  
Screw Dislocations ◽  
Hexagonal Close Packed ◽  
Applied Shear Stress ◽  
Dislocation Movement ◽  
Twinning Direction

The behavior of the screw dislocation core in the presence of an external shear stress has been examined for the body-centered cubic and hexagonal close-packed phases of a model sodium lattice, using an effective ion–ion potential calculated from first principles. The Peierls stress for screw dislocations in the b.c.c. lattice at 0 °K is dependent on the orientation of the applied shear stress, and has a minimum value of 0.0105G, where G is the shear modulus, for slip in the twinning direction on {112} planes. The Peierls stress in the h.c.p. lattice is at least 25 times smaller. Dislocation movement in the model b.c.c. lattice takes place by unit translations on {110} planes, with the selection rule that no two consecutive translations can take place on the same slip plane.

scholarly journals Evaluation of Aberration-corrected Optical Sectioning for Exploring the Core Structure of ½[111] Screw Dislocations in BCC Metals

2017 ◽  
Vol 23 (S1) ◽  
pp. 432-433
Author(s):  
D. Hernandez-Maldonado ◽  
R. Groger ◽  
Q. M. Ramasse ◽  
P. B. Hirsch ◽  
P.D. Nellist
Keyword(s):  
Core Structure ◽  
Optical Sectioning ◽  
Screw Dislocations ◽  
The Core ◽  
Bcc Metals ◽  
Aberration Corrected

DISSOCIATED DISLOCATIONS AND THE SCHMID LAW OF RESOLVED SHEAR STRESS IN b.c.c. METALS

1967 ◽  
Vol 45 (2) ◽  
pp. 939-943 ◽  
Author(s):  
F. R. N. Nabarro ◽  
T. R. Duncan
Keyword(s):  
Shear Stress ◽  
Partial Dislocation ◽  
Shear Stresses ◽  
Screw Dislocations ◽  
The Core

The dissociation of screw dislocations on [Formula: see text] planes in a b.c.c. metal can lead to unequal shear stresses for glide in opposite directions, while dissociation on [Formula: see text] planes cannot. Glide will occur in the former configuration only if the radius of the core of a partial dislocation exceeds [Formula: see text] of the radius of a symmetrically dissociated dislocation. If this condition is not satisfied, one partial dislocation runs to infinity before the remaining two coalesce.

scholarly journals Exaggerated cation leak from oxygenated sickle red blood cells during deformation: evidence for a unique leak pathway

Blood ◽  
1992 ◽  
Vol 80 (9) ◽  
pp. 2374-2378
Author(s):  
T Sugihara ◽  
RP Hebbel
Keyword(s):  
Shear Stress ◽  
Lipid Hydroperoxide ◽  
Viscous Medium ◽  
Permeability Barrier ◽  
Biochemical Basis ◽  
Rbc Membrane ◽  
Gardos Channel ◽  
Ambient Oxygen ◽  
Applied Shear Stress ◽  
Leak Pathway

An abnormal susceptibility of the sickle red blood cell (RBC) membrane to deformation could compromise its permeability barrier function and contribute to the exuberant cation leakiness occurring during the sickling phenomenon. We examined this hypothesis by subjecting RBCs at ambient oxygen tension to elliptical deformation, applying shear stress in a viscous medium under physiologic conditions. Compared with normal and high-reticulocyte control RBCs, sickle RBCs manifest an exaggerated K leak response to deformation. This leak is fully reversible, is both Cl and Ca independent, and at pHe 7.4 is fully balanced so that Kefflux equals Nainflux. This abnormal susceptibility is also evident in that the K leak in response to deformation occurs at an applied shear stress of only 141 dyne/cm2 for sickle RBCs, as compared to 204 dyne/cm2 for normal RBCs. Fresh sickle RBC membranes contain elevated amounts of lipid hydroperoxide, the presence of which is believed to provide the biochemical basis for enhanced deformation susceptibility. When examined at pHe 6.8, oxygenated sickle RBCs acquire an additional, unbalanced (Kefflux > Nainflux) component to the K leak increment specifically ascribable to deformation. Studies with inhibitors suggest that this additional component is not caused by a known leak pathway (eg, either K:Cl cotransport or the Gardos channel). This abnormal susceptibility of the sickle membrane to development of cation leakiness during deformation probably contributes to the exuberant cation leak taking place during RBC sickling.

MAGNETOPHORETIC CIRCUIT BIOCOMPATIBILITY

2020 ◽  
Vol 20 (07) ◽  
pp. 2050050
Author(s):  
ROOZBEH ABEDINI-NASSAB
Keyword(s):  
Shear Stress ◽  
Single Cell ◽  
Single Cell Analysis ◽  
Cell Behavior ◽  
Cell Analysis ◽  
Applied Shear Stress ◽  
Cell Handling ◽  
Magnetic Labeling ◽  
Long Term Studies

Recently, we introduced magnetophoretic circuits, composed of overlaid magnetic and metallic layers, as a novel single-cell analysis (SCA) tool. We showed the ability of these circuits in organizing large single-particle and particle-pair arrays. Assembling the cells in microarrays is performed with the ultimate goal of running temporal phenotypic analyses. However, for long-term studies, a suitable microenvironment for the cells to normally grow and differentiate is needed. Towards this goal, in this study, we run required biocompatibility tests, based on which we make the magnetophoretic-based microchip a suitable home for the cells to grow. The results confirm the ability of these chips in cell handling and show no unwanted cell behavior alteration due to the applied shear stress on them, the magnetic labeling, or the microenvironment. After this achievement, this tool would be ready for running important single-cell studies in oncology, virology, and medicine.

First-Principles Study of Structural and Defect Properties in FeCo Intermetallics

2004 ◽  
Vol 842 ◽  
Author(s):  
M. Krcmar ◽  
C. L. Fu ◽  
J. R. Morris
Keyword(s):  
Shear Stress ◽  
Ab Initio ◽  
Structural Stability ◽  
First Principles ◽  
Statistical Thermodynamic ◽  
Internal Stresses ◽  
Applied Shear Stress ◽  
Defect Energies ◽  
Antisite Defects ◽  
B2 Structure

ABSTRACTEmploying ab-initio calculations and statistical thermodynamic modeling, we investigated the structural stability, defect energies, and ordering of B2 FeCo intermetallics. We find that FeCo in the B2 structure is a marginally stable and weakly ordered system, with a high density of antisite defects on both sublattices and low APB energies for the <111> slip on both {110} and {112} planes. The structural stability of B2 FeCo is very sensitive to the change in local atomic environment, as the system transforms to a lower-symmetry L10 phase under the effects of reduced dimensionality or applied shear stress. We suggest that internal stresses near dislocation cores might be closely connected with the intrinsic brittleness of ordered FeCo, as it is likely to induce a local structural transformation from the B2 structure to the L10 structure.

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