The Yield Shear Stress of Blood in Branched Models of the Microcirculation

2015 ◽  
pp. 14-20
Author(s):  
H. Kiesewetter ◽  
H. Radtke ◽  
H. Schmid-Sch�nbein
Keyword(s):  
Shear Stress ◽  
Yield Shear Stress

Comparison of Linear Visco-Elastic Complex Modulus and Yield Shear Stress in DSR Moisture Damage Test

2009 ◽  
Vol 37 (6) ◽  
pp. 102178
Author(s):  
M. R. Mitchell ◽  
R. E. Link ◽  
Dong-Woo Cho ◽  
Tai Sik Lee ◽  
SangYum Lee ◽  
...  
Keyword(s):  
Shear Stress ◽  
Complex Modulus ◽  
Moisture Damage ◽  
Yield Shear Stress

Mechanical and Optical Properties Characterization of C-Plane (0001) and M-Plane (10−10) GaN by Nanoindentation and Luminescence

2015 ◽  
Vol 1792 ◽  
Author(s):  
Toshiya Yokogawa ◽  
Masaki Fujikane ◽  
Shijo Nagao ◽  
Roman Nowak
Keyword(s):  
Plastic Deformation ◽  
Shear Stress ◽  
Dislocation Density ◽  
Twin Boundary ◽  
Boundary Energy ◽  
Dynamics Simulation ◽  
Dark Spot ◽  
Yield Shear Stress ◽  
Gan Crystal

ABSTRACTYield shear stress dependence on dislocation density and crystal orientation was studied in bulk GaN crystals by nanoindentation examination. The yield shear stress decreased with increasing dislocation density which is estimated by dark spot density in cathodoluminescence, and it decreased with decreasing nanoindentation strain-rate. It reached and coincided at 11.5 GPa for both quasi-static deformed c-plane (0001) and m-plane (10-10) GaN. Taking into account theoretical Peierls–Nabarro stress and yield stress for each slip system, these phenomena were concluded to be an evidence of heterogeneous mechanism associated plastic deformation in GaN crystal. Transmission electron microscopy and molecular dynamics simulation also supported the mechanism with obtained r-plane (-1012) slip line right after plastic deformation, so called pop-in event. The agreement of the experimentally obtained atomic shuffle energy with the calculated twin boundary energy suggested that the nucleation of the local metastable twin boundary along the r-plane concentrated the indentation stress, leading to an r-plane slip. This nanoindentation examination is useful for the characterization of crystalline quality because the wafer mapping of the yield shear stress coincided the photoluminescence mapping which shows increase of emission efficiency due to reduction of non-radiative recombination process by dislocation.

Simulated Behavior of a System With Base Excitation Using an Electrorheological Fluid Damper

1993 ◽  
Author(s):  
Paul N. Rieder ◽  
John A. Tichy
Keyword(s):  
Shear Stress ◽  
Electric Field ◽  
Vibration Isolation ◽  
Fluid Model ◽  
Electrorheological Fluid ◽  
Isolation System ◽  
Yield Shear Stress ◽  
Linear Behavior ◽  
Two Parameters ◽  
Er Fluids

Abstract The flow properties of electrorheological (ER) fluids change with the application of an electric field. Presently, these materials are a novelty with few direct applications, but they have drawn considerable interest. Proposed applications include lubricants, dampers, clutches, brakes, etc. Existing ER fluids are best described by the Bingham fluid model. The Bingham material is described by two parameters, a yield shear stress and a viscosity. When the shear stress magnitude exceeds the yield shear stress, quasi-Newtonian flow results; otherwise the material is rigid. For many ER fluids, the yield shear stress is proportional to the square of the applied electric field. In the present study, the Bingham model is applied to a rectangular flow channel. A rigid core forms midway across the film, the core thickness being proportional to the yield shear stress. The damper force is predicted as a function of a dimensionless parameter which depends on the yield shear stress, the flow rate, and channel geometry. Calculations are performed for a simple vibration isolation system. Such a system may represent a smart shock absorber to minimize vibration response to oscillation input from a bumpy road. The ER damper is shown to be effective in isolating vibration within a band of linear behavior.

Anisotropy in Plastic Torsion

1972 ◽  
Vol 94 (1) ◽  
pp. 231-237 ◽  
Author(s):  
J. A. Bailey ◽  
S. L. Haas ◽  
K. C. Nawab
Keyword(s):  
Experimental Data ◽  
Shear Stress ◽  
Shear Strain ◽  
Yield Stress ◽  
Hollow Cylinder ◽  
Experimental Measurement ◽  
Tangential Strain ◽  
Yield Shear Stress ◽  
Hollow Cylinders ◽  
Von Mises

An analysis is presented which shows how the theory of anisotropy based on a von Mises criterion of yielding first proposed by Hill may be extended to the plastic torsional straining of a hollow cylinder. Expressions are given for the anisotropic parameters, and the yield stresses along the anisotropic axes in terms of certain quantities, namely; the change in axial and tangential strain with shear strain, the principal yield shear stress, and the through thickness yield stress of the hollow cylinder. Experimental measurement of these quantities is made for the plastic torsional straining of hollow cylinders of A1-1100. Experimental data are analyzed using the previously derived expressions, and the anisotropic parameters, and yield stresses along the anisotropic axes determined. Finally, the results of the investigation are discussed, and conclusions drawn.

Yield shear stress dependence on nanoindentation strain rate in bulk GaN crystal

2011 ◽  
Vol 8 (2) ◽  
pp. 429-431 ◽  
Author(s):  
Masaki Fujikane ◽  
Toshiya Yokogawa ◽  
Shijo Nagao ◽  
Roman Nowak
Keyword(s):  
Shear Stress ◽  
Strain Rate ◽  
Stress Dependence ◽  
Yield Shear Stress ◽  
Bulk Gan ◽  
Gan Crystal

Fundamental Process Mechanics Common to Machining and Grinding Operations

2020 ◽  
Author(s):  
Wolfgang Lortz ◽  
Radu Pavel
Keyword(s):  
Shear Stress ◽  
Strain Rate ◽  
Plastic Flow ◽  
Material Behavior ◽  
Workpiece Material ◽  
Yield Shear Stress ◽  
Rate Versus ◽  
Wide Range ◽  
Process Mechanics ◽  
Grinding Operations

Abstract All different production processes have one thing in common: in each case a workpiece with characteristic material behavior, stress, strain, self-hardening and temperature will be produced by a tool with special geometry and individual kinematic conditions, with a wide range of energy in a designed machine tool which is working along programmed lines. For the workpiece material, it is not important from which machine the energy is coming. To be able to predict more accurate values of the production process, it will be necessary to focus more on the complex and difficult process mechanics. The result must have a strong physical base and be in good agreement with practical results To solve these problems, we have to uncover all previous simplification assumptions for the existing models. This leads in a first step to a new fundament in process mechanics, which is only based on mathematics, physics and material behavior with friction conditions, and resulting temperatures during metal plastic flow. The new mathematical equations developed for yield shear stress and strain rate will be presented and discussed in this paper. The plastic deformation is the only parameter that will not disappear after completing the operation. Therefore, this will be the base to compare the developed theoretical deformation with the experimental results for two operations: cutting and grinding. In addition, it could be shown that yield shear stress and corresponding strain rate versus temperatures have an interdependent relationship, which creates the opportunity to determine the temperatures during metal plastic flow.

Yield shear stress and disaggregating shear stress of human blood

2014 ◽  
Vol 26 (2) ◽  
pp. 191-198 ◽  
Author(s):  
Jinmu Jung ◽  
Byoung-Kwon Lee ◽  
Sehyun Shin
Keyword(s):  
Shear Stress ◽  
Human Blood ◽  
Yield Shear Stress

Rheology of human blood and hyperlipemia

1964 ◽  
Vol 19 (3) ◽  
pp. 493-496 ◽  
Author(s):  
E. W. Merrill ◽  
E. R. Gilliland ◽  
W. G. Margetts ◽  
F. T. Hatch
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Blood Rheology ◽  
Coaxial Cylinder ◽  
Temperature Relation ◽  
Square Roots ◽  
Triglyceride Concentration ◽  
Yield Shear Stress ◽  
Physiological Relevance ◽  
Feature Based

By means of an electromagnetic coaxial cylinder viscometer, the blood from two hyperlipemic patients was studied near and at zero shear rate. The basic data: shear stress versus shear rate, were transformed to the respective square roots and plotted against each other. The resulting plots are linear, clearly defining at zero shear rate the yield shear stress and showing obedience to the Casson equation. The principal feature discovered from these data is that a) the yield shear stress reaches a maximum around 3 hr after ingestion of a fatty meal, this maximum being substantially greater than that of blood from the fasting subject, and b) the triglyceride concentration continues to rise to a maximum around 6 hr after ingestion, by which time the yield shear stress is approaching the normal value. A second feature, based on only one of the two subjects, is that the yield shear stress increases markedly as temperature of the blood decreases. Some comments are offered on the possible physiological relevance of the data and possible biophysical interpretations. low shear rheology; yield shear stress of lipemic blood; blood rheology-temperature relation; blood triglyceride concentration and yield shear stress Submitted on August 9, 1963

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