Loading history dependence of stress field around salt diapirs due to path dependence of visco-elasto-plastic rheology

2020 ◽  
Author(s):  
Ibragimov Iskander ◽  
Yury Podladchikov ◽  
Artem Myasnikov
Keyword(s):  
Path Dependence ◽  
Sedimentary Basin ◽  
Salt Diapir ◽  
Flow Modeling ◽  
Loading History ◽  
Stress Evolution ◽  
Time Step ◽  
Lower Viscosity ◽  
Geomechanical Property ◽  
As Stress

<p>One of the most unstable and unpredictable process in sedimentary basin is salt diapir movement. It changes the structure of strata and can break its integrity and make trap structures for hydrocarbons. The movement of salt diapir through geologic timescale can be described in viscous terms, elastic terms were used to predict the geomechanical response of sediment surroundings.</p><p>This work describes the workflow of visco-elastic flow modeling of salt diapirism process. Salt has different geomechanical property such as much lower viscosity comparing to typical sediments. Mixed rheology make different geomechanical response such as stress, which cannot be solved in the same timescale.  To solve the problem of different timescales of viscous and elastic flow there was used a pseudo-transient method of solving the system of equations. Used equations calculate full stress tensors and pressure over time which can help in understanding of stress evolution around salt diapir. Maximizing time step during each calculation was accomplished with density scaling, which assumes that inertial forces are negligible.</p><p>The used approach allows taking into account the loading history and easily can be supplemented with sedimentation mechanisms.</p>

CFD Investigation of Gear Pump Mixing Using Deforming/Agglomerating Mesh

2006 ◽  
Vol 129 (4) ◽  
pp. 476-484 ◽  
Author(s):  
Wayne Strasser
Keyword(s):  
Large Scale ◽  
Accurate Solution ◽  
Progression Rate ◽  
Gear Pump ◽  
Feed Stream ◽  
Time Step ◽  
Pump Speed ◽  
Lower Viscosity ◽  
Fluid Properties ◽  
Process Fluid

A moving-deforming grid study was carried out using a commercial computational fluid dynamics (CFD) solver, FLUENT® 6.2.16. The goal was to quantify the level of mixing of a lower-viscosity additive (at a mass concentration below 10%) into a higher-viscosity process fluid for a large-scale metering gear pump configuration typical in plastics manufacturing. Second-order upwinding and bounded central differencing schemes were used to reduce numerical diffusion. A maximum solver progression rate of 0.0003 revolutions per time step was required for an accurate solution. Fluid properties, additive feed arrangement, pump scale, and pump speed were systematically studied for their effects on mixing. For each additive feed arrangement studied, the additive was fed in individual stream(s) into the pump-intake. Pump intake additive variability, in terms of coefficient of spatial variation (COV), was >300% for all cases. The model indicated that the pump discharge additive COV ranged from 45% for a single centerline additive feed stream to 5.5% for multiple additive feed streams. It was found that viscous heating and thermal/shear-thinning characteristics in the process fluid slightly improved mixing, reducing the outlet COV to 3.2% for the multiple feed-stream case. The outlet COV fell to 2.0% for a half-scale arrangement with similar physics. Lastly, it was found that if the smaller unit’s speed were halved, the outlet COV was reduced to 1.5%.

Modeling stress evolution around a rising salt diapir

2014 ◽  
Vol 51 ◽  
pp. 230-238 ◽  
Author(s):  
Maria A. Nikolinakou ◽  
Peter B. Flemings ◽  
Michael R. Hudec
Keyword(s):  
Salt Diapir ◽  
Stress Evolution ◽  
Modeling Stress

Factors affecting microstructural scale in liquid crystalline polymers

1990 ◽  
Vol 48 (4) ◽  
pp. 220-221
Author(s):  
Christine M. Dannels ◽  
Christopher Viney
Keyword(s):  
Liquid Crystalline ◽  
Liquid Crystalline Polymers ◽  
Factors Affecting ◽  
Crystalline Polymers ◽  
Thermal Expansion Coefficients ◽  
Low Thermal Expansion ◽  
Lower Viscosity ◽  
Fine Microstructure ◽  
Planar Orientation ◽  
Strength And Stiffness

Processing polymers from the liquid crystalline state offers several advantages compared to processing from conventional fluids. These include: better axial strength and stiffness in fibers, better planar orientation in films, lower viscosity during processing, low solidification shrinkage of injection moldings (thermotropic processing), and low thermal expansion coefficients. However, the compressive strength of the solid is disappointing. Previous efforts to improve this property have focussed on synthesizing stiffer molecules. The effect of microstructural scale has been overlooked, even though its relevance to the mechanical and physical properties of more traditional materials is well established. By analogy with the behavior of metals and ceramics, one would expect a fine microstructure (i..e. a high density of orientational defects) to be desirable.Also, because much microstructural detail in liquid crystalline polymers occurs on a scale close to the wavelength of light, light is scattered on passing through these materials.

Toward a neuroscope: An application of high-performance computing for real-time evaluation of brain function using MRI

1994 ◽  
Vol 52 ◽  
pp. 922-923
Author(s):  
C. S. Potter ◽  
C. D. Gregory ◽  
H. D. Morris ◽  
Z.-P. Liang ◽  
P. C. Lauterbur
Keyword(s):  
Human Brain ◽  
Brain Function ◽  
High Performance ◽  
Complex Signal ◽  
Time Step ◽  
Brain Organization ◽  
Cognitive Studies ◽  
Positron Emission ◽  
Imaging And Spectroscopy ◽  
3D Anatomy

Over the past few years, several laboratories have demonstrated that changes in local neuronal activity associated with human brain function can be detected by magnetic resonance imaging and spectroscopy. Using these methods, the effects of sensory and motor stimulation have been observed and cognitive studies have begun. These new methods promise to make possible even more rapid and extensive studies of brain organization and responses than those now in use, such as positron emission tomography.Human brain studies are enormously complex. Signal changes on the order of a few percent must be detected against the background of the complex 3D anatomy of the human brain. Today, most functional MR experiments are performed using several 2D slice images acquired at each time step or stimulation condition of the experimental protocol. It is generally believed that true 3D experiments must be performed for many cognitive experiments. To provide adequate resolution, this requires that data must be acquired faster and/or more efficiently to support 3D functional analysis.

Arthroscintigraphy in Suspected Rotator Cuff Rupture

1998 ◽  
Vol 37 (08) ◽  
pp. 272-278 ◽  
Author(s):  
S. Gratz ◽  
G. Köster ◽  
T. Behr ◽  
R. Vosshenrich ◽  
E. Grabbe ◽  
...  
Keyword(s):  
Rotator Cuff ◽  
Shoulder Joint ◽  
Clinical Signs ◽  
Diagnostic Efficiency ◽  
Rotator Cuff Rupture ◽  
Lower Viscosity ◽  
Rotator Cuff Lesion ◽  
Shoulder Region ◽  
Degenerative Alterations ◽  
Additional Value

Summary Aim: In order to evaluate the diagnostic efficiency of arthroscintigraphy in suspected rotator cuff ruptures this new imaging procedure was performed 20 times in 17 patients with clinical signs of a rotator cuff lesion. The scintigraphic results were compared with sonography (n = 20), contrast arthrography (n = 20) and arthroscopy (n = 10) of the shoulder joint. Methods: After performing a standard bone scintigraphy with intravenous application of 300 MBq 99m-Tc-methylene diphosphonate (MDP) for landmarking of the shoulder region arthroscintigraphy was performed after an intraarticular injection of 99m-Tc microcolloid (ALBURES 400 μCi/5 ml). The application was performed either in direct combination with contrast arthrography (n = 10) or ultrasound conducted mixed with a local anesthetic (n = 10). Findings at arthroscopical surgery (n = 10) were used as the gold standard. Results: In case of complete rotator cuff rupture (n = 5), arthroscintigraphy and radiographic arthrography were identical in 5/5. In one patient with advanced degenerative alterations of the shoulder joint radiographic arthrography incorrectly showed a complete rupture which was not seen by arthroscintigraphy and endoscopy. In 3 patients with incomplete rupture, 2/3 results were consistant. A difference was seen in one patient with a rotator cuff, that has been already revised in the past and that suffered of capsulitis and calcification. Conclusion: Arthroscintigraphy is a sensitive technique for detection of rotator cuff ruptures. Because of the lower viscosity of the active compound, small ruptures can be easily detected, offering additional value over radiographic arthrography and ultrasound, especially for evaluation of incomplete cuff ruptures.

From transaction costs to transaction value: Overcoming the frictional paradigm

2020 ◽  
pp. 51-81
Author(s):  
D. P. Frolov
Keyword(s):  
Transaction Costs ◽  
Transaction Cost ◽  
Path Dependence ◽  
Transaction Cost Economics ◽  
Cost Minimization ◽  
Low Cost ◽  
Coase Theorem ◽  
Transactional Analysis ◽  
Transaction Sector ◽  
Transaction Value

The transaction cost economics has accumulated a mass of dogmatic concepts and assertions that have acquired high stability under the influence of path dependence. These include the dogma about transaction costs as frictions, the dogma about the unproductiveness of transactions as a generator of losses, “Stigler—Coase” theorem and the logic of transaction cost minimization, and also the dogma about the priority of institutions providing low-cost transactions. The listed dogmas underlie the prevailing tradition of transactional analysis the frictional paradigm — which, in turn, is the foundation of neo-institutional theory. Therefore, the community of new institutionalists implicitly blocks attempts of a serious revision of this dogmatics. The purpose of the article is to substantiate a post-institutional (alternative to the dominant neo-institutional discourse) value-oriented perspective for the development of transactional studies based on rethinking and combining forgotten theoretical alternatives. Those are Commons’s theory of transactions, Wallis—North’s theory of transaction sector, theory of transaction benefits (T. Sandler, N. Komesar, T. Eggertsson) and Zajac—Olsen’s theory of transaction value. The article provides arguments and examples in favor of broader explanatory possibilities of value-oriented transactional analysis.

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