Influence of Shear Rate History on Generation of Shear-Induced Structure of Wormlike Micelles Solutions

2011 ◽  
Author(s):  
Shogo Chiba ◽  
Masatoshi Ito ◽  
Shuji Fujii ◽  
Tsutomu Takahashi
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Shear Flow ◽  
Wormlike Micelles ◽  
Acceleration Rate ◽  
History Of ◽  
The Moment ◽  
Evolution Behavior ◽  
The Relationship ◽  
Shear Induced Structure

The influence of the history of the shear rate on generation of shear hardening phenomenon of wormlike micelles aqueous solutions was investigated. An accelerated shear flow was applied to change the shear rate history and the influence of an acceleration rate on the time evolution behavior of the shear stress was observed. The relationship between the strain and the shear stress is given by one curve that is independent of a history of shear rate if the shear rate or the accelerated shear coefficient is higher than a certain critical value. A very high shear rate flow can be caused without the shear hardening by using the slowly accelerated shear flow but the SIS is generated if the shear rate in the moment exceeds the critical shear rate of the SIS formation.

Game Theory vs. Business Ethics

2015 ◽  
pp. 1849-1872
Author(s):  
Ben Tran
Keyword(s):  
Game Theory ◽  
Business Ethics ◽  
Emerging Economies ◽  
Moral Philosopher ◽  
John Von Neumann ◽  
Von Neumann ◽  
Economic Behaviour ◽  
History Of ◽  
The Moment ◽  
The Relationship

In 1954, the British philosopher Richard Braithwaite gave his inaugural lecture, Theory of Games as a Tool for the Moral Philosopher. Braithwaite predicted game theory would fundamentally change moral philosophy. However, in hindsight, John von Neumann and Oskar Morgenstern's publication of Theory of Games and Economic Behaviour was the moment modern game theory entered the discipline of ethics. The purpose of this chapter is to analyze the relationship between game theory and business ethics. In other words, this chapter explains how game theory plays a role in business ethics and affects business ethics for emerging economies and covers in detail: 1) the history of game theory; 2) types of/definition(s) of games; 3) business ethics; 4) business; and 5) ethics. The chapter concludes with the role that game theory and business ethics play in emerging economies.

The Rheological Characterization of the Writing Performance of Carbon Black Gel Ink

2009 ◽  
Vol 66 ◽  
pp. 139-142 ◽  
Author(s):  
Ji Jun Qian ◽  
Ai Ping Chen ◽  
Zhong Xin Liu ◽  
Chun Zhong Li
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Carbon Black ◽  
Rheological Parameters ◽  
Rheological Characterization ◽  
Writing Performance ◽  
Strong Shear ◽  
The Common ◽  
The Relationship

The rheological properties of carbon black gel ink were investigated by measurement the relationship between shear stress and shear rate. The fitting to the common rheological curve of gel ink with Hersegel-Bulkley equation was introduced. And the rheological parameters used to characterize the writing properties of gel ink were proposed. The results indicated that the gel ink system possessed strong shear-thinning ability. And the writing performance of the gel ink could be characterized with rheological parameters comprehensively.

scholarly journals Endothelial shear rate, local and regional vascular stiffness in patients in different stages of atherogenesis

2016 ◽  
Vol 15 (3) ◽  
pp. 50-56
Author(s):  
V. V. Genkel ◽  
A. O. Salachenko ◽  
O. A. Alekseeva ◽  
I. I. Shaposhnik
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Carotid Artery ◽  
Common Carotid Artery ◽  
Carotid Arteries ◽  
Vascular Stiffness ◽  
Stiffness Index ◽  
The Common ◽  
Relationship Of ◽  
The Relationship

Introduction and purpose. Endothelial cells are subjected to biomechanical stress produced by the bloodstream and tunica media of the vessel. Vascular stiffness and endothelial shear stress have cooperative effects on the endothelial structure and function. However, the relationship of shear stress and arterial stiffness is still poorly understood. The purpose of the study was to assess the relationship of endothelial shear rate and both local and regional vascular stiffness in patients at different stages of the development of atherosclerosis. Methods. The study included 60 patients, 33 men and 27 women. The average age of patients was 54.8±11.7 years. Regional arterial stiffness was assessed by measurement of the pulse wave velocity in the arteries of elastic and muscular types. Local stiffness of the carotid arteries was characterized by Peterson elastic modulus, Young's modulus, stiffness index β, the deformation of the common carotid artery. Endothelial shear rate was measured at the site of the common carotid artery. Results. Average values of carotid endothelial shear rate were equal to 433±127 s-1. Reduced endothelial shear rate in the carotid arteries was associated with an increased Peterson modulus (r = -0.289; p = 0.025) and the stiffness index β (r = -0.280; p = 0.037), and moreover - with decreasing vascular distensibility (r = 0.288; p = 0.026) and deformation (r = 0.296; p = 0.024). Assessment of the relationship between endothelial shear rate and regional vascular stiffness showed weak statistically significant negative correlation of shear rate and PWVcf (r = -0.367; p = 0.014). Conclusion. In study subjects endothelial shear rate reduction in the area of the common carotid artery was associated with an increased Peterson modulus, stiffness index β, decreasing deformation of carotid arteries and increase in aortic stiffness.

scholarly journals Artificial surface effect on red blood cells and platelets in laminar shear flow

Blood ◽  
1990 ◽  
Vol 75 (7) ◽  
pp. 1568-1575
Author(s):  
TM Alkhamis ◽  
RL Beissinger ◽  
JR Chediak
Keyword(s):  
Shear Stress ◽  
Platelet Aggregation ◽  
Shear Rate ◽  
Shear Flow ◽  
Platelet Adhesion ◽  
Surface Effect ◽  
Test Surface ◽  
Adp Release ◽  
Laminar Shear Flow ◽  
Laminar Shear

Red blood cell (RBC) effects on platelet adhesion to a nonbiologic test surface (tetrafluoroethylene propylene copolymer) and platelet aggregation during laminar shear flow for shear rates to 5,680 s-1 (corresponding to shear stress to 200 dyne/cm2) were investigated. Results on hemoglobin (Hb) and adenosine diphosphate (ADP) release from RBCs, percent decrease of single platelets in the bulk, and percent of test surface covered with platelets were obtained in a cone-and-plate (CP) viscometer for samples of whole blood, suspensions of RBC ghosts in platelet-rich plasma (PRP), and suspensions of RBCs in either PRP or platelet-poor plasma. Results obtained over the shear rate range studied for samples of normal hematocrit indicated that low-stress shearing led to ADP and Hb release from intact RBCs; shear-induced release of ADP from RBCs was about twice that of platelets, and of the total ADP released, the ADP released from RBCs contributed about six times that of the platelets to single platelet reduction in the bulk and about twice that of the platelets to platelet adhesion, ie, coverage of the test surface with platelets. Results obtained for various hematocrits showed that above a threshold hematocrit of about 25% to 35% the RBCs (suspended in PRP) had a greater contribution to ADP release, platelet adhesion, and platelet aggregation than the platelets themselves. Single platelet reduction for samples of RBC ghosts suspended in PRP correlated with shear rate level and not with shear stress.

scholarly journals Artificial surface effect on red blood cells and platelets in laminar shear flow

Blood ◽  
1990 ◽  
Vol 75 (7) ◽  
pp. 1568-1575 ◽  
Author(s):  
TM Alkhamis ◽  
RL Beissinger ◽  
JR Chediak
Keyword(s):  
Shear Stress ◽  
Platelet Aggregation ◽  
Shear Rate ◽  
Shear Flow ◽  
Platelet Adhesion ◽  
Surface Effect ◽  
Test Surface ◽  
Adp Release ◽  
Laminar Shear Flow ◽  
Laminar Shear

Abstract Red blood cell (RBC) effects on platelet adhesion to a nonbiologic test surface (tetrafluoroethylene propylene copolymer) and platelet aggregation during laminar shear flow for shear rates to 5,680 s-1 (corresponding to shear stress to 200 dyne/cm2) were investigated. Results on hemoglobin (Hb) and adenosine diphosphate (ADP) release from RBCs, percent decrease of single platelets in the bulk, and percent of test surface covered with platelets were obtained in a cone-and-plate (CP) viscometer for samples of whole blood, suspensions of RBC ghosts in platelet-rich plasma (PRP), and suspensions of RBCs in either PRP or platelet-poor plasma. Results obtained over the shear rate range studied for samples of normal hematocrit indicated that low-stress shearing led to ADP and Hb release from intact RBCs; shear-induced release of ADP from RBCs was about twice that of platelets, and of the total ADP released, the ADP released from RBCs contributed about six times that of the platelets to single platelet reduction in the bulk and about twice that of the platelets to platelet adhesion, ie, coverage of the test surface with platelets. Results obtained for various hematocrits showed that above a threshold hematocrit of about 25% to 35% the RBCs (suspended in PRP) had a greater contribution to ADP release, platelet adhesion, and platelet aggregation than the platelets themselves. Single platelet reduction for samples of RBC ghosts suspended in PRP correlated with shear rate level and not with shear stress.

Shear Flow and Large Amplitude Oscillation Shear Study of Solutions of Aggregating Micellar Casein Particles

2008 ◽  
Vol 18 (2) ◽  
pp. 23050-1-23050-7 ◽  
Author(s):  
Anne Pitkowski ◽  
Taco Nicolai ◽  
Dominique Durand
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Shear Flow ◽  
Heating Temperature ◽  
Constant Shear ◽  
Micellar Casein ◽  
Large Amplitude Oscillation ◽  
Increasing Temperature ◽  
Small Shear ◽  
Constant Shear Rate

Abstract Small micellar casein particles were formed in aqueous solutions of native casein after addition of polyphosphate. These so-called submicelles aggregated and gelled with a rate that increased with increasing temperature. The evolution of the viscosity during this process was determined at constant shear rate or shear stress. When applying a small shear stress the viscosity increased strongly until the shear rate became immeasurably slow, but when the applied shear stress exceeded a critical value (σc) the aggregates broke up and the viscosity reached a maximum. At longer times the viscosity decreased rapidly at first, followed by a very slow decrease. σc was independent of the shear rate and heating temperature, but increased strongly with increasing casein concentration. At constant shear rate the stress remained close to σc, but fluctuated irregularly. After cessation of shear flow, gels were formed rapidly. Oscillation shear measurements for σ > σc showed a strongly non-linear response at the time of maximum viscosity.

Iraq and the mutual accumulation strategy between the international and regional powers: The United States of America and Iran are a model

2020 ◽  
pp. 125
Author(s):  
Salah Mahdi Hadi ◽  
Noor Abdul-Ilah Ajrash
Keyword(s):  
United States ◽  
United States Of America ◽  
The United States ◽  
The Political ◽  
Regional Powers ◽  
Hostage Crisis ◽  
History Of ◽  
The Moment ◽  
The Relationship

The rules of (mutual accumulation strategy) overshadow the history of the crisis relations between the United States of America and Iran four decades ago, and if we recall that, we will notice several collision joints between the two parties, starting with the hostage crisis of the American embassy in Iran from 4/11/1979 to 20 / 1/1981 AD, to the "Marines" attempt to storm this embassy in an operation called "Eagle Claw" on 4/24/1980 AD, to the tanker war in the eighties of the last century, to the exchange of downing drones in 2019, and finally what happened between the United States The United States and Iran from the moment targeting (Qassem Soleimani), commander of the "Quds Force" on 1/3/2020, until the Iranian missile response and targeting of the American forces in the two "Ain al-Assad" bases in Anbar province, and the "Harir" base in Arbil province on 1/8/ 2020 AD, all of this falls within the context of (mutual accumulation strategy) between the two parties, without going to a comprehensive confrontation through war or a knockout, because the logic of war or comprehensive confrontation is outside the political and military mindsets of the two parties, and the meaning of all of this is that turmoil forms the basis of the relationship between the states The The United States and Iran, because the turmoil and the limited clash with it through mutual strikes, do not necessarily lead to an open clash.

scholarly journals Blood flow in small tubes: quantifying the transition to the non-continuum regime

2013 ◽  
Vol 722 ◽  
pp. 214-239 ◽  
Author(s):  
Huan Lei ◽  
Dmitry A. Fedosov ◽  
Bruce Caswell ◽  
George Em Karniadakis
Keyword(s):  
Blood Flow ◽  
Shear Stress ◽  
Shear Rate ◽  
Shear Flow ◽  
Dissipative Particle Dynamics ◽  
Stress Gradient ◽  
Velocity Slip ◽  
Similarity Function ◽  
Density Peak ◽  
Tube Size

AbstractIn small vessels blood is usually treated as a Newtonian fluid down to diameters of${\sim }200~\mathrm{\mu} \mathrm{m} $. We investigate the flow of red blood cell (RBC) suspensions driven through small tubes (diameters$10\text{{\ndash}} 150~\mathrm{\mu} \mathrm{m} $) in the range marking the transition from arterioles and venules to the largest capillary vessels. The results of the simulations combined with previous simulations of uniform shear flow and experimental data show that for diameters less than${\sim }100~\mathrm{\mu} \mathrm{m} $the suspension’s stress cannot be described as a continuum, even a heterogeneous one. We employ the dissipative particle dynamics (DPD) model, which has been successfully used to predict human blood bulk viscosity in homogeneous shear flow (Fedosovet al. Proc. Natl Acad. Sci. USA, vol. 108, 2011, pp. 11772–11777). In tube flow the cross-stream stress gradient induces an inhomogeneous distribution of RBCs featuring a centreline cell density peak, and a cell-free layer (CFL) next to the wall. For a neutrally buoyant suspension the imposed linear shear-stress distribution together with the differentiable velocity distribution allow the calculation of the local viscosity across the tube section. The viscosity across the section as a function of the strain rate is found to be essentially independent of tube size for the larger diameters and is determined by the local haematocrit ($H$) and shear rate. Other RBC properties such as asphericity, deformation, and cell-flow orientation exhibit similar dependence for the larger tube diameters. As the tube size decreases below${\sim }100~\mathrm{\mu} \mathrm{m} $in diameter, the viscosity in the central region departs from the large-tube similarity function of the shear rate, since$H$increases significantly towards the centreline. The dependence of shear stress on tube size, in addition to the expected local shear rate and local haematocrit, implies that blood flow in small tubes cannot be described as a heterogeneous continuum. Based on the analysis of the DPD simulations and on available experimental results, we propose a simple velocity-slip model that can be used in conjunction with continuum-based simulations.

scholarly journals Progressive handgrip exercise: evidence of nitric oxide-dependent vasodilation and blood flow regulation in humans

2011 ◽  
Vol 300 (3) ◽  
pp. H1101-H1107 ◽  
Author(s):  
D. Walter Wray ◽  
Melissa A. H. Witman ◽  
Stephen J. Ives ◽  
John McDaniel ◽  
Anette S. Fjeldstad ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Shear Stress ◽  
Shear Rate ◽  
Vascular Endothelial Cells ◽  
Peripheral Circulation ◽  
No Synthase ◽  
Handgrip Exercise ◽  
Endothelial No Synthase ◽  
Exercise Induced ◽  
The Relationship

In the peripheral circulation, nitric oxide (NO) is released in response to shear stress across vascular endothelial cells. We sought to assess the degree to which NO contributes to exercise-induced vasodilation in the brachial artery (BA) and to determine the potential of this approach to noninvasively evaluate NO bioavailability. In eight young (25 ± 1 yr) healthy volunteers, we used ultrasound Doppler to examine BA vasodilation in response to handgrip exercise (4, 8, 12, 16, 20, and 24 kg) with and without endothelial NO synthase blockade [intra-arterial NG-monomethyl-l-arginine (l-NMMA), 0.48 mg·dl−1·min−1]. Higher exercise intensities evoked significant BA vasodilation (4–12%) that was positively correlated with the hyperemic stimulus ( r = 0.98 ± 0.003, slope = 0.005 ± 0.001). During NO blockade, BA vasodilation at the highest exercise intensity was reduced by ∼70% despite similar exercise-induced increases in shear rate (control, +224 ± 30 s−1; l-NMMA, +259 ± 46 s−1). The relationship and slope of BA vasodilation with increasing shear rate was likewise reduced ( r = 0.48 ± 0.1, slope = 0.0007 ± 0.0005). We conclude that endothelial NO synthase inhibition with l-NMMA abolishes the relationship between shear stress and BA vasodilation during handgrip exercise, providing clear evidence of NO-dependent vasodilation in this experimental model. These results support this paradigm as a novel and valid approach for a noninvasive assessment of NO-dependent vasodilation in humans.

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