scholarly journals Correlation between crustal high conductivity zones and seismic activity and the role of carbon during shear deformation

2008 ◽  
Vol 113 (B12) ◽  
Author(s):  
Paul W. J. Glover ◽  
A. Ádám
Keyword(s):  
Shear Deformation ◽  
Seismic Activity ◽  
High Conductivity

The role of shear deformation in pure tungsten: Mechanical properties and micro-mechanism

2021 ◽  
pp. 2150142
Author(s):  
Ping Li ◽  
Juan-Juan Shu ◽  
Lu-Sheng Wang ◽  
Miao Meng ◽  
Ke-Min Xue
Keyword(s):  
Mechanical Properties ◽  
Shear Deformation ◽  
Strain Curve ◽  
Shear Angle ◽  
Pure Tungsten ◽  
Stress Strain Curve ◽  
Additional Increase ◽  
Dislocation Strengthening ◽  
Band Deformation

The effects of shear deformation at 1173 K on the mechanical properties and deformation mechanism of pure tungsten are investigated by molecular dynamics (MD). The results show that the shear deformation of pure tungsten is dominated by dislocation multiplication and slip band deformation. The shear angle has a significant effect on the mechanical properties of pure tungsten. The yield strength is 4.21 Gpa at a shear angle of 11[Formula: see text], and it increases significantly to 11.84 Gpa while the shear angle increasing to 27[Formula: see text]. In the plastic deformation stage, the stress–strain curve shows obvious oscillation due to the interaction of dislocations in the single-crystal tungsten and the effect of strain strengthening. In addition, the evolution of dislocation and twining in the compression system against shear angle indicates the variation of deformation behavior. When the shear angle is 11[Formula: see text], the lengths of dislocation 1/2[Formula: see text] and [Formula: see text] increase to a peak rapidly, which illustrates dislocation strengthening. However, when the shear angle is more than 11[Formula: see text], the decrease of dislocation length and the appearance of twins along [Formula: see text] direction demonstrate the twining accompanied with dislocation tangling, resulting in the additional increase of strength.

scholarly journals Impact of earthquake-triggered landslides on catchment sediment yield

2015 ◽  
Vol 367 ◽  
pp. 291-296
Author(s):  
M. Vanmaercke ◽  
F. Obreja ◽  
J. Poesen
Keyword(s):  
Sediment Yield ◽  
Seismic Activity ◽  
Fold Increase ◽  
Sediment Concentration ◽  
Spatial And Temporal Variation ◽  
Strongly Correlated ◽  
Before And After ◽  
Sediment Export

Abstract. This study explores the role of seismic activity in explaining spatial and temporal variation in sediment export from the Siret basin in Romania. Based on long-term (>30 years) sediment export measurements for 38 subcatchments, we found that spatial variation in sediment yield (SY) is strongly correlated to the degree of seismic activity and catchment lithology. Combined, these factors explain 80% of the variation in SY. To investigate the role of earthquake-triggered landslides in explaining these correlations, we studied the temporal variability in sediment concentrations before and after the 7.4 Mw earthquake of 1977 for ten subcatchments. Despite the fact that this earthquake triggered many landslides, only one subcatchment showed a clear (3-fold) increase in sediment concentration per unit discharge after the earthquake. This shows that, although prolonged seismic activity strongly controls average SY, individual earthquakes do not necessarily affect sediment export at short timescales.

scholarly journals The role of shear deformation component in pressure welding samples of dissimilar cast and wrought nickel-based alloys

2016 ◽  
Vol 6 (3) ◽  
pp. 211-216 ◽  
Author(s):  
A. Kh. Akhunova ◽  
E. V. Galieva ◽  
A. A. Drozdov ◽  
E. G. Arginbava ◽  
S. V. Dmitriev ◽  
...  
Keyword(s):  
Shear Deformation ◽  
Pressure Welding ◽  
Deformation Component

When Science Meets Responsibility: The Major Risks Commission and the L’Aquila Earthquake

2014 ◽  
Vol 5 (2) ◽  
pp. 146-158 ◽  
Author(s):  
Marta Simoncini
Keyword(s):  
Risk Assessment ◽  
Risk Communication ◽  
Future Development ◽  
Seismic Activity ◽  
Research Question ◽  
L’Aquila Earthquake ◽  
Civil Protection ◽  
Risk Regulation ◽  
Main Research

This article aims to analyse the role of law in the identification of the responsibility domain of ‘regulatory science’ (Jasanoff, 1990) within the risk regulatory process. The main research question is therefore,what kindof relationshipbetween science andpolicy-making lawshould design in risk regulation.In order to address this issue, this contribution focuses on the recent verdict of the Tribunal of L’Aquila. After the earthquake occurred in L’Aquila on the 6th April 2009, six Italian scientists that had participated in the Major Risks Commission's meeting have been condemned for the multiple manslaughter of 29 people who were among the 309 victims of the earthquake, ‘for having assessed the risks related to seismic activity in the L’Aquila territory in an inaccurate, generic and ineffective way’ and for having provided ‘information which was imprecise, incomplete and contradictory as to the nature, the causes and the hazardousness and on the future development of the seismic activity’.As far as risk assessment and risk communication are concerned, firstly the tasks of the Major Risks Commission under the Italian Civil Protection law will be analysed. Against this backdrop, the issues related to this expert body's responsibility will be addressed and the gaps in the current accountability regime will be pointed out.

scholarly journals Positive or negative Poynting effect? The role of adscititious inequalities in hyperelastic materials

2011 ◽  
Vol 467 (2136) ◽  
pp. 3633-3646 ◽  
Author(s):  
L. Angela Mihai ◽  
Alain Goriely
Keyword(s):  
Shear Deformation ◽  
Simple Shear ◽  
Shear Force ◽  
Pure Shear ◽  
Hyperelastic Materials ◽  
Isotropic Materials ◽  
Poynting Effect ◽  
Simple Shear Deformation ◽  
Biopolymer Gels

Motivated by recent experiments on biopolymer gels whereby the reverse of the usual (positive) Poynting effect was observed, we investigate the effect of the so-called ‘adscititious inequalities’ on the behaviour of hyperelastic materials subject to shear. We first demonstrate that for homogeneous isotropic materials subject to pure shear, the resulting deformation consists of a triaxial stretch combined with a simple shear in the direction of the shear force if and only if the Baker–Ericksen inequalities hold. Then for a cube deformed under pure shear, the positive Poynting effect occurs if the ‘sheared faces spread apart’, whereas the negative Poynting effect is obtained if the ‘sheared faces draw together’. Similarly, under simple shear deformation, the positive Poynting effect is obtained if the ‘sheared faces tend to spread apart’, whereas the negative Poynting effect occurs if the ‘sheared faces tend to draw together’. When the Poynting effect occurs under simple shear, it is reasonable to assume that the same sign Poynting effect is obtained also under pure shear. Since the observation of the negative Poynting effect in semiflexible biopolymers implies that the (stronger) empirical inequalities may not hold, we conclude that these inequalities must not be imposed when such materials are described.

An experimental study of the role of shear deformation on partial melting of a synthetic metapelite

2011 ◽  
Vol 503 (1-2) ◽  
pp. 92-99 ◽  
Author(s):  
Elizaveta Tumarkina ◽  
Santanu Misra ◽  
Luigi Burlini ◽  
James A.D. Connolly
Keyword(s):  
Experimental Study ◽  
Partial Melting ◽  
Shear Deformation

scholarly journals The role of annealing in determining the yielding behavior of glasses under cyclic shear deformation

2021 ◽  
Vol 118 (16) ◽  
pp. e2100227118
Author(s):  
Himangsu Bhaumik ◽  
Giuseppe Foffi ◽  
Srikanth Sastry
Keyword(s):  
Shear Deformation ◽  
Strain Amplitude ◽  
Threshold Energy ◽  
Cyclic Shear ◽  
Annealing Regime ◽  
Uniform Shear ◽  
High Annealing ◽  
Wide Range ◽  
Yielding Behavior

Yielding behavior in amorphous solids has been investigated in computer simulations using uniform and cyclic shear deformation. Recent results characterize yielding as a discontinuous transition, with the degree of annealing of glasses being a significant parameter. Under uniform shear, discontinuous changes in stresses at yielding occur in the high annealing regime, separated from the poor annealing regime in which yielding is gradual. In cyclic shear simulations, relatively poorly annealed glasses become progressively better annealed as the yielding point is approached, with a relatively modest but clear discontinuous change at yielding. To understand better the role of annealing on yielding characteristics, we perform athermal quasistatic cyclic shear simulations of glasses prepared with a wide range of annealing in two qualitatively different systems—a model of silica (a network glass) and an atomic binary mixture glass. Two strikingly different regimes of behavior emerge. Energies of poorly annealed samples evolve toward a unique threshold energy as the strain amplitude increases, before yielding takes place. Well-annealed samples, in contrast, show no significant energy change with strain amplitude until they yield, accompanied by discontinuous energy changes that increase with the degree of annealing. Significantly, the threshold energy for both systems corresponds to dynamical cross-over temperatures associated with changes in the character of the energy landscape sampled by glass-forming liquids.

Thermomechanical evolution of the high-grade core in the nappe zone of Variscan Sardinia, Italy: the role of shear deformation and granite emplacement

2016 ◽  
Vol 34 (4) ◽  
pp. 321-342 ◽  
Author(s):  
G. Cruciani ◽  
M. Franceschelli ◽  
H.-J. Massonne ◽  
G. Musumeci ◽  
M. E. Spano
Keyword(s):  
Shear Deformation ◽  
High Grade ◽  
Granite Emplacement
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