Influence of Extensional Stress Overshoot on Crystallization of LDPE

2017 ◽  
Vol 50 (3) ◽  
pp. 1134-1140 ◽  
Author(s):  
Sara Lindeblad Wingstrand ◽  
Martin van Drongelen ◽  
Kell Mortensen ◽  
Richard S. Graham ◽  
Qian Huang ◽  
...  
Keyword(s):  
Stress Overshoot ◽  
Extensional Stress

Cenozoic extensional stress evolution in North China

2003 ◽  
Vol 36 (5) ◽  
pp. 591-613 ◽  
Author(s):  
Zhang Yueqiao ◽  
Ma Yinsheng ◽  
Yang Nong ◽  
Shi Wei ◽  
Dong Shuwen
Keyword(s):  
North China ◽  
Stress Evolution ◽  
Extensional Stress

scholarly journals On the stress overshoot in cluster crystals under shear

2020 ◽  
Vol 23 (2) ◽  
pp. 23801
Author(s):  
Shrivastav ◽  
Kahl
Keyword(s):  
Stress Overshoot

On the polymer entropic force singularity and its relation to extensional stress relaxation and filament recoil

2004 ◽  
Vol 48 (1) ◽  
pp. 209-221 ◽  
Author(s):  
Eric S. G. Shaqfeh ◽  
Gareth H. McKinley ◽  
Nathanael Woo ◽  
D. A. Nguyen ◽  
Tam Sridhar
Keyword(s):  
Stress Relaxation ◽  
Entropic Force ◽  
Extensional Stress

scholarly journals Boundary layer models for calving marine outlet glaciers

2017 ◽  
Vol 11 (5) ◽  
pp. 2283-2303 ◽  
Author(s):  
Christian Schoof ◽  
Andrew D. Davis ◽  
Tiberiu V. Popa
Keyword(s):  
Boundary Layer ◽  
Ice Sheets ◽  
Ice Thickness ◽  
Ice Shelf ◽  
Bedrock Channel ◽  
Extensional Stress ◽  
Grounding Line ◽  
Direct Numerical Solution ◽  
Glacier Ice ◽  
Side Walls

Abstract. We consider the flow of marine-terminating outlet glaciers that are laterally confined in a channel of prescribed width. In that case, the drag exerted by the channel side walls on a floating ice shelf can reduce extensional stress at the grounding line. If ice flux through the grounding line increases with both ice thickness and extensional stress, then a longer shelf can reduce ice flux by decreasing extensional stress. Consequently, calving has an effect on flux through the grounding line by regulating the length of the shelf. In the absence of a shelf, it plays a similar role by controlling the above-flotation height of the calving cliff. Using two calving laws, one due to Nick et al. (2010) based on a model for crevasse propagation due to hydrofracture and the other simply asserting that calving occurs where the glacier ice becomes afloat, we pose and analyse a flowline model for a marine-terminating glacier by two methods: direct numerical solution and matched asymptotic expansions. The latter leads to a boundary layer formulation that predicts flux through the grounding line as a function of depth to bedrock, channel width, basal drag coefficient, and a calving parameter. By contrast with unbuttressed marine ice sheets, we find that flux can decrease with increasing depth to bedrock at the grounding line, reversing the usual stability criterion for steady grounding line location. Stable steady states can then have grounding lines located on retrograde slopes. We show how this anomalous behaviour relates to the strength of lateral versus basal drag on the grounded portion of the glacier and to the specifics of the calving law used.

THE EFFECTS OF EXTENSIONAL STRESS ON RED BLOOD CELL HEMOLYSIS

2015 ◽  
Vol 27 (05) ◽  
pp. 1550042 ◽  
Author(s):  
Jen-Hong Yen ◽  
Sheng-Fu Chen ◽  
Ming-Kai Chern ◽  
Po-Chien Lu
Keyword(s):  
Shear Stress ◽  
Blood Cell ◽  
Prediction Models ◽  
Cell Damage ◽  
Threshold Value ◽  
Shear Stresses ◽  
Flow Conditions ◽  
Extensional Stress ◽  
Computational Fluid Dynamics Cfd ◽  
Stress Flow

Artificial prostheses create non-physiologic flow conditions with stress forces that may induce blood cell damage, particularly hemolysis. Earlier computational fluid dynamics (CFD) prediction models based on a quantified power model showed significant discrepancies with actual hemolysis experiments. These models used the premise that shear stresses act as the primary force behind hemolysis. However, additional studies have suggested that extensional stresses play a more substantial role than previously thought and should be taken into account in hemolysis models. We compared extensional and shear stress flow fields within the contraction of a short capillary with sharp versus tapered entrances. The flow field was calculated with CFD to determine stress values, and hemolysis experiments with porcine red blood cells were performed to correlate the effects of extensional and shear stress on hemolysis. Our results support extensional stress as the primary mechanical force involved in hemolysis, with a threshold value of 1000 Pa under exposure time less than 0.060 ms.

Double Stress Overshoot in Start-Up of Simple Shear Flow of Entangled Comb Polymers

2013 ◽  
Vol 2 (7) ◽  
pp. 601-604 ◽  
Author(s):  
F. Snijkers ◽  
D. Vlassopoulos ◽  
G. Ianniruberto ◽  
G. Marrucci ◽  
H. Lee ◽  
...  
Keyword(s):  
Shear Flow ◽  
Simple Shear ◽  
Simple Shear Flow ◽  
Comb Polymers ◽  
Stress Overshoot ◽  
Start Up

Investigating the role of transient rapid trench retreat in initiating rifting of a mobile overriding plate during subduction

2021 ◽  
Author(s):  
Zhibin Lei ◽  
Huw Davies
Keyword(s):  
Steady State ◽  
Stress Field ◽  
Transition Zone ◽  
Subduction Zones ◽  
Dominant Role ◽  
Op Amp ◽  
Driving Mechanisms ◽  
Extensional Stress ◽  
Wide Range ◽  
Break Up

<p>Trench retreat, or slab roll-back, has been proposed to account for various degrees of extensional deformation within the overriding plate in subduction zones, eg. Izu-Bonin-Mariana, Tonga etc. However, the relationship between trench retreat rate and the degree of extension has not been rigorously tested. Here we obtain a wide range of trench retreat rate by varying the initial age of subducting plate (SP, Age<sup>0</sup><sub>SP</sub>) and overriding plate (OP, Age<sup>0</sup><sub>OP</sub>) met at trench. Then we investigate how much trench retreat rate is needed to initiate rifting in the OP.</p><p>The results show that models would evolve from a non-steady state towards a steady state as the SP sinks to the transition zone at 660 km.</p><p>Before the SP starts to interact with the transition zone, the trench retreat rate accelerates with time reaching a maximum value (v<sub>max</sub>), which can be very high but only lasts a short time (~0.5 Myr). For models with a given OP, v<sub>max </sub>is Age<sup>0</sup><sub>SP</sub>-dependent. The trench retreat rate, on the other hand, determines the extensional extent within the OP. With increasing Age<sup>0</sup><sub>SP</sub>, a minimum trench retreat rate (v<sub>rift</sub>) is needed to initiate rifting within the OP. For models with Age<sup>0</sup><sub>OP </sub>= 20 Myr and Age<sup>0</sup><sub>OP </sub>= 25 Myr, v<sub>rift</sub> is ~19 cm/yr and ~27 cm/yr separately. This implies that an older OP is more resistant to extensional stress field driven by trench retreat. In all, three types of stretching states are observed within the OP in our models: i) minor extension, where v<sub>max</sub><v<sub>rift</sub> and the OP lithosphere has little extension; ii) rift, where v<sub>max</sub>≈v<sub>rift</sub> and the OP would rift but not be torn apart; iii) break-up, where v<sub>max</sub>>v<sub>rift</sub> and the OP would rift when the trench retreat rate reaches v<sub>rift</sub>, then breaks up into two parts after it exceeds v<sub>rift</sub>. We note all three states involve different extents of mantle wedge erosion at ~100 km away from the trench underneath the OP, while rifting and break-up occur >700 km away from the trench. In the break-up cases, the two parts of the OP can be ~250 km apart.</p><p>After the SP reaches the transition zone, the trench retreat rate would drop to a constant magnitude around 2 cm/yr and lose the Age<sup>0</sup><sub>SP</sub>-dependency. This is because the viscosity jump at the transition zone prevents the SP from accelerating into the lower mantle. Meanwhile, the Age<sup>0</sup><sub>SP</sub>-dependent negative buoyancy loses its dominant role in driving the trench retreat.</p><p>We discuss two driving mechanisms to relate the initiation of extension with rapid trench retreat (trench suction): 1) focused upwelling from the transition zone; 2) horizontal basal drag. We conclude that the transient rapid trench retreat can lead to an extensional stress field through basal drag which is strong enough to initiate rifting or even break-up within a mobile overriding plate. A high negative SP buoyancy could play the driving force to generate this transient rapid trench retreat.</p>

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