scholarly journals INFLUENCE OF RELAXATION PROCESSES ON MECHANICAL STRESS SHIFTS IN AMORPHOUS AND NANOCRYSTALLINE RIBBON ALLOYS AT ELECTROPULSE EXPOSURE

2017 ◽  
Vol 60 (7) ◽  
pp. 538-543
Author(s):  
D. Yu. Fedotov ◽  
S. A. Sidorov ◽  
V. A. Fedorov ◽  
T. N. Pluzhnikova ◽  
A. V. Yakovlev
2008 ◽  
Vol 1086 ◽  
Author(s):  
Alexei L. Romanov ◽  
Alexei E. Romanov

AbstractPentagonal nanorods (PNRs) are crystalline objects with unique fivefold symmetry. They are often experimentally observed for materials with FCC crystal structure. In an ideal case a PNR consists of five elastically distorted but otherwise perfect crystalline regions divided by low-energy twin boundaries. The elastic distortions in PNRs and associated stored elastic energy are effectively described in the framework of a disclination approach. As a result of mechanical stress relaxation, the stored energy can be diminished in expense of structural defect formation in PRN interior. It is demonstrated that a perfect multiple twinned PNR structure is unstable with respect to dislocation formation, i.e. prismatic dislocation loop or straight edge dislocation, for PNRs above a certain critical diameter. A new mechanism for the relaxation processes in PNRs is theoretically investigated. This mechanism assumes the formation of the shell possessing crystal lattice mismatch with respect to the PNR core region. The optimal magnitude for core/shell crystal lattice mismatch and optimal shell thickness providing maximum energy release for this mechanism of mechanical stress relaxation, are predicted.


2012 ◽  
Vol 55 (1) ◽  
Author(s):  
Dimos Triantis ◽  
Filippos Vallianatos ◽  
Ilias Stavrakas ◽  
George Hloupis

<p>The emission of electrical signals during application of mechanical stress to brittle geo-materials (the so-called pressure-stimulated current; PSC) can provide significant information regarding the mechanical status of a studied rock sample. PSCs originate as a result of the opening of cracks and microfractures in rock. In this study, such electrical signal emissions are detected and studied when rock samples are subjected to step-wise mechanical stress, increased from low stress levels vL up to higher stress levels vH. This increase is performed at high stress rates and consequently the stress is maintained practically constant for a long period. During this time, the applied stress reaches its maximum value, and the emitted PSC decays gradually and relaxes back to a minimum value. The conducted experiments suggest that the characteristics of the relaxation processes of the PSC depend directly on the high level of the applied stress that is maintained constant after the application of each stress step. Analysis of the macroscopic parameters that characterize the relaxation phenomenon of the PSC provides clear information regarding the proximity of the applied stress to the fracture limit of the rock sample.</p>


2003 ◽  
Vol 112 ◽  
pp. 943-946 ◽  
Author(s):  
K. Koho ◽  
J. Vimpari ◽  
L. Straka ◽  
N. Lanska ◽  
O. Sôderberg ◽  
...  
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1977 ◽  
Vol 37 (02) ◽  
pp. 329-338 ◽  
Author(s):  
Tadahiro Sano ◽  
Takeshi Motomiya ◽  
Hiroh Yamazaki ◽  
Takio Shimamoto

SummaryA new method for assessment of platelet sensitivity to ADP-aggregation was devised. Its reproducibility and the correlations between the values obtained by this method, the optical density (O. D.) method, and the screen filtration pressure (SFP) method were assessed. In summary, this method may be said to have three main points:1. It can be performed without centrifugation, avoiding mechanical stress to platelets, using only 0.8 ml. of blood and inexpensive equipment.2. It may reflect different aspects of platelet function from the O. D. method and the SFP method, despite the positive significant correlations between the values obtained by these three methods.3. It was proved to be highly reproducible and is thought to be useful clinically.By using this method, the effect of sustained isometric exercise by handgripping on platelet aggregability was assessed in coronary sclerotic and cerebral arteriosclerotic patients on placebo and EG-626, a newly synthesized cyclic AMP phosphodiesterase inhibitor. On placebo, an enhancement of platelet sensitivity was observed after isometric exercise in coronary and cerebral arteriosclerotic patients but not in healthy control subjects. The enhancement was prevented by pretreatment of EG-626, administered orally 1.5 hours prior to exercise.


Author(s):  
А. А. Горват ◽  
В. М. Кришеник ◽  
А. Е. Кріштофорій ◽  
В. В. Мінькович ◽  
О. А. Молнар

2019 ◽  
Vol 64 (1-2) ◽  
pp. 75-82
Author(s):  
F. Nekvapil ◽  
◽  
Cs. Müller Molnár ◽  
S. Tomšić ◽  
S. Cintă Pinzaru ◽  
...  

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