scholarly journals Studies with Rheological Behavior of Composite Lithium-Based Magnetorheological Grease

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1826
Author(s):  
Hua Yan ◽  
Pingyang Li ◽  
Chi Duan ◽  
Xiaomin Dong
Keyword(s):  
Shear Stress ◽  
Maximum Yield ◽  
Experimental Results ◽  
Magnetic Flux Density ◽  
Qualitative And Quantitative Analysis ◽  
Rheological Behaviors ◽  
Settlement Behavior ◽  
Shear Yield ◽  
Mr Effect ◽  
Low Shear

Magnetorheological (MR) grease has advantages of the anti-settlement behavior and excellent sealing property compared with conventional MR materials. However, the rheological behaviors of MR effect and shear yield stress are too small to limit the further applications with MR grease. This paper proposes a composite lithium-based MR grease with boric acid-hydroxyl stearic acid to improve the rheological behaviors. Eight different samples of composite lithium-based MR grease with different ratios of mass between lithium stearate and lithium borate are prepared by the saponification method. The rheological behaviors are tested and discussed with qualitative and quantitative analysis. The experimental results show that the off-state viscosity reduces with the decrement of the ratio of mass under low shear rate which changes from 68.7 Pa·s to 16.5 Pa·s. Lithium stearate content has more effects with off-state viscosity. Based on the Herschel-Bingham model, the shear stress of composite lithium-based MR grease can be improved dramatically by adjusting the ratio of mass which is increased by 170% under the magnetic flux density of 0.2 T. Compared with single lithium-based MR grease, the maximum yield shear stress is increased by 166.7% at off-state and the maximum MR effect is also increased by 19.1%. The MR effect can reach 23,600% with a specific mass ratio of the composite MR grease. The experimental results validate that the feasibility of the performance improvement by the composite lithium-based MR grease.

Test Method for Rheological Behaviors of Magnetorheological Grease Based on Coaxial Cylinder Shear Mode and Rheometer

2011 ◽  
Vol 291-294 ◽  
pp. 1929-1934
Author(s):  
Li Juan Fu ◽  
Chang Rong Liao ◽  
Jian Zuo Ma
Keyword(s):  
Shear Stress ◽  
Angular Velocity ◽  
Magnetic Flux ◽  
Flux Density ◽  
Coaxial Cylinder ◽  
Approximate Algorithm ◽  
Magnetic Flux Density ◽  
Shear Mode ◽  
Rheological Behaviors ◽  
Test Methodology

A test methodology for rheological behaviors of MR greases based on double rotational coaxial cylinder shear mode is presented in this paper. Both flow velocity profiles and shear stress profiles of MR greases in shear channels are analytically explored. The theory relationship between shear stress acted on MR greases and transmission torques is established, an approximate algorithm is put forwarded to acquire nominal shear stresses by transmission torques. On the basis of differential equation and its rational boundary conditions from stress equilibrium of MR greases micro-unit, an approximate corresponding algorithm is worked out for nominal shear strain rates by rotor angular velocities. The relationship between average value of magnetic flux density in annular channels and excitation electrical currents are experimentally obtained. Based on test methodology above-mentioned, a rheometer is fabricated and modulated, in which torque sensor, angular velocity sensor and ampere meter are respectively used to test transmission torque, angular velocity and electrical current. Rheological parameters of MR grease from the rheometer, whose shear rate is more than 2000 1/s and magnetic flux density acting on MR greases exceed 0.6T, are in good agreement with those from test conduced by commercial theological rheometer.

Low shear stress-induced endothelial mesenchymal transformation via the down-regulation of TET2

2021 ◽  
Vol 545 ◽  
pp. 20-26
Author(s):  
AFang Li ◽  
LiLan Tan ◽  
ShuLei Zhang ◽  
Jun Tao ◽  
Zuo Wang ◽  
...  
Keyword(s):  
Shear Stress ◽  
Down Regulation ◽  
Low Shear Stress ◽  
Mesenchymal Transformation ◽  
Low Shear

Investigation on the Rheological Behavior of Polyamide6/Montmorillonite Nanocomposites by Reactive Extrusion

2011 ◽  
Vol 233-235 ◽  
pp. 1998-2001 ◽  
Author(s):  
Ming Zhao ◽  
Xiao Zhong Lu ◽  
Kai Gu ◽  
Xiao Min Sun ◽  
Chang Qing Ji
Keyword(s):  
Activation Energy ◽  
Shear Stress ◽  
Shear Rate ◽  
Rheological Behavior ◽  
Reactive Extrusion ◽  
Shear Thinning ◽  
Experimental Results ◽  
Montmorillonite Nanocomposites

The rheological behavior of PA6/montmorillonite(MMT) by reactive extrusion was investigated using cone-and-plate rheometer. The experimental results indicated that PA6/MMT exhibited shear-thinning behavior. The shear stress of both neat PA6 and PA6/MMT increased with the increase in the shear rate. The reduction of the viscous activation energy with the increase of shear stress reflected PA6/MMT can be processed over a wider temperature.

Plaque and Shear Stress Distribution in Human Coronary Bifurcations: a Multi-Slice Computed Tomography Study

2007 ◽  
Author(s):  
Alina G. van der Giessen ◽  
Jolanda J. Wentzel ◽  
Frans N. van de Vosse ◽  
Antonius F. van der Steen ◽  
Pim J. de Feyter ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Shear Stress ◽  
Outer Wall ◽  
Atherosclerotic Plaques ◽  
Advanced Stage ◽  
Flow Divider ◽  
Low Shear Stress ◽  
Curved Vessels ◽  
Early Atherosclerosis ◽  
Low Shear

It is generally accepted that early atherosclerosis develops in low shear-stress (SS) regions such as the outer wall of arterial bifurcations and the inner bend of curved vessels (1). However, in clinical practice, it is common to observe atherosclerotic plaques at the flow-divider, or carina, of coronary bifurcations (2). Plaques at the carina are more frequently found in symptomatic patients, and may represent a more advanced stage of atherosclerosis. The carina is located in a region which is exposed to high SS. We hypothesize that if plaques are located in atheroprotective high SS regions, they have grown circumferentially from the atherogenic low SS regions.

CXCR4 expression in atherosclerotic lesions induced by low shear stress

2008 ◽  
Vol 32 (3) ◽  
pp. S18-S19
Author(s):  
Dang Heng Wei ◽  
Gui Xue Wang ◽  
Yi Ping Xia ◽  
Jian Jun Lei ◽  
Lu Shang Liu ◽  
...  
Keyword(s):  
Shear Stress ◽  
Cxcr4 Expression ◽  
Atherosclerotic Lesions ◽  
Low Shear Stress ◽  
Low Shear

scholarly journals Low Shear Stress Induced HMGB1 Translocation and Release via PECAM-1/PARP-1 Pathway to Induce Inflammation Response

PLoS ONE ◽  
2015 ◽  
Vol 10 (3) ◽  
pp. e0120586 ◽  
Author(s):  
Wei-dong Qin ◽  
Shao-hua Mi ◽  
Chen Li ◽  
Gui-xia Wang ◽  
Jian-ning Zhang ◽  
...  
Keyword(s):  
Shear Stress ◽  
Inflammation Response ◽  
Low Shear Stress ◽  
Parp 1 ◽  
Low Shear

Wall-shear stress patterns of coherent structures in turbulent duct flow

2009 ◽  
Vol 633 ◽  
pp. 147-158 ◽  
Author(s):  
SEBASTIAN GROSSE ◽  
WOLFGANG SCHRÖDER
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
Wall Shear Stress ◽  
Coherent Structures ◽  
Shear Stress Distribution ◽  
Duct Flow ◽  
Wall Shear Stress Distribution ◽  
Wall Shear ◽  
Turbulent Duct Flow ◽  
Low Shear

The wall-shear stress distribution in turbulent duct flow has been assessed using the micro-pillar shear-stress sensor MPS3. The spatial resolution of the sensor line is 10.8l+(viscous units) and the total field of view of 120l+along the spanwise direction allows to capture characteristic dimensions of the wall-shear stress distribution at sufficiently high resolution. The results show the coexistence of low-shear and high-shear regions representing ‘footprints’ of near-wall coherent structures. The regions of low shear resemble long meandering bands locally interrupted by areas of higher shear stress. Conditional averages of the flow field indicate the existence of nearly streamwise counter-rotating vortices aligned in the streamwise direction. The results further show periods of very strong spanwise wall-shear stress to be related to the occurrence of high streamwise shear regions and momentum transfer towards the wall. These events go along with a spanwise oscillation and a meandering of the low-shear regions.

QS358. Programmed Cell Death in Low Shear Stress and Balloon Induced Arterial Restenosis

2008 ◽  
Vol 144 (2) ◽  
pp. 409-410
Author(s):  
Lisa R.P. Spiguel ◽  
Amito Chandiwal ◽  
Ralph R. Weichselbaum ◽  
Christopher L. Skelly
Keyword(s):  
Cell Death ◽  
Shear Stress ◽  
Programmed Cell Death ◽  
Arterial Restenosis ◽  
Low Shear Stress ◽  
Low Shear
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