Micro-mechanical theory of shear yield stress for strongly flocculated colloidal gel

Soft Matter ◽  
2020 ◽  
Vol 16 (7) ◽  
pp. 1801-1809 ◽  
Author(s):  
Saikat Roy ◽  
Mahesh S. Tirumkudulu
Keyword(s):  
Yield Stress ◽  
Constitutive Relation ◽  
Volume Fraction ◽  
Mechanical Theory ◽  
Shear Yield Stress ◽  
Interparticle Potential ◽  
Shear Yield ◽  
Colloidal Gel ◽  
Scale Properties

We derive a constitutive relation for shear yield stress of strongly aggregated colloidal gel as a function of interparticle potential, volume fraction, contact scale properties and gel microstructure.

The shear and compressive yield stress of fibrillated acacia pulp fiber suspensions

2020 ◽  
Vol 35 (2) ◽  
pp. 243-250
Author(s):  
Jiulong Sha ◽  
Yueyue Yang ◽  
Can Wang ◽  
Wei Li ◽  
Peng Lu ◽  
...  
Keyword(s):  
Yield Stress ◽  
Paper Industry ◽  
Pulp Fiber ◽  
Fiber Suspensions ◽  
Fiber Morphology ◽  
Shear Yield Stress ◽  
Geometrical Properties ◽  
Compressive Yield Stress ◽  
Shear Yield ◽  
Fiber Cell Wall

AbstractThe degree of interactions between fibers and the tendency of fibers to form flocs play an important role in effective unit operation in pulp and paper industry. Mechanical treatments may damage the structure of the fiber cell wall and geometrical properties, and ultimately change the fiber-fiber interactions. In this study, the gel crowding number, compressive and shear yield stress of fibrillated acacia pulps were investigated, and the results showed that the gel crowding number of the refined pulp samples ranged from 8.7 to 10.7, which were much lower than that of un-refined pulps. As the concentration increased, both the compressive yield stress {P_{y}} and shear yield stress {\tau _{y}} of all suspensions increased accordingly, and the yield stress was found to depend on a power law of the crowding number. Moreover, the values of {\tau _{y}}/{P_{y}} were also examined and the variation of {\tau _{y}}/{P_{y}} became largely dependent on the fiber morphology and mass concentration.

Shear yield stress of partially flocculated colloidal suspensions

AIChE Journal ◽  
1998 ◽  
Vol 44 (3) ◽  
pp. 538-544 ◽  
Author(s):  
Peter J. Scales ◽  
Stephen B. Johnson ◽  
Thomas W. Healy ◽  
Prakash C. Kapur
Keyword(s):  
Yield Stress ◽  
Colloidal Suspensions ◽  
Shear Yield Stress ◽  
Shear Yield

Demonstration of Combined Shear and Squeeze Strengthening Modes in a Searle-Type Magnetorheometer

2013 ◽  
Author(s):  
Andrew C. Becnel ◽  
Norman M. Wereley
Keyword(s):  
Yield Stress ◽  
Energy Absorption ◽  
Shear Yield Stress ◽  
Particle Chain ◽  
Solids Loading ◽  
Mr Fluids ◽  
Shear Yield ◽  
Microstructure Model ◽  
Novel Method ◽  
A Chain

This research details a novel method of increasing the shear yield stress of magnetorheological (MR) fluids by combining shear and squeeze modes of operation to manipulate particle chain structures, to achieve so-called compression-assisted aggregation. The contribution of both active gap separation and particle concentration are experimentally measured using a custom-built Searle cell magnetorheometer, which is a model device emulating a rotary Magnetorheological Energy Absorber (MREA). Characterization data from large (1 mm) and small (250 μm) gap geometries are compared to investigate the effect of the gap on yield stress by compression enhancement. Two MR fluids having different particle concentrations (32 vol% and 40 vol%) are also characterized to demonstrate the effect of solids loading on compression-assisted chain aggregation. Details of the experimental setup and method are presented, and a chain microstructure model is used to explain experimental trends. The torque resisted by practical rotary MREAs is directly related to the strength of the MR fluid used, as measured by the shear yield stress. This study demonstrates that it is feasible, utilizing the compression-enhanced shear yield stress, to either (1) design a rotary MREA of a given volume to achieve higher energy absorption density (energy absorbed normalize by device volume), or (2) reduce the volume of a given rotary MREA to achieve the same energy absorption density.

Compression Enhanced Shear Yield Stress of Electrorheological Fluid

2009 ◽  
Vol 26 (4) ◽  
pp. 048301 ◽  
Author(s):  
Zhang Min-Liang ◽  
Tian Yu ◽  
Jiang Ji-Le ◽  
Zhu Xu-Li ◽  
Meng Yong-Gang ◽  
...  
Keyword(s):  
Yield Stress ◽  
Electrorheological Fluid ◽  
Shear Yield Stress ◽  
Shear Yield

Effect of annealing on the shear yield stress of rejuvenated polycarbonate

Polymer ◽  
1988 ◽  
Vol 29 (11) ◽  
pp. 1985-1989 ◽  
Author(s):  
C. Bauwens-Crowet ◽  
J-C. Bauwens
Keyword(s):  
Yield Stress ◽  
Shear Yield Stress ◽  
Shear Yield

ELECTRORHEOLOGICAL BEHAVIOR OF CHITOSAN DERIVATIVE SUSPENSIONS

2001 ◽  
Vol 15 (06n07) ◽  
pp. 1025-1032 ◽  
Author(s):  
Ung-su Choi ◽  
Byeng-gil Ahn ◽  
Oh-kwan Kwon
Keyword(s):  
Electric Field ◽  
Volume Fraction ◽  
Silicone Oil ◽  
Flow Behavior ◽  
Chitosan Derivative ◽  
Shear Yield Stress ◽  
Bingham Flow ◽  
Shear Yield ◽  
The Difference ◽  
Er Fluid

The electrorheological (ER) behavior of chitosan and chitosan phosphate suspensions in silicone oil was investigated. Chitosan and chitosan phosphate suspensions showed a typical ER response (Bingham flow behavior) upon application of an electric field. However, chitosan phosphate suspension exhibited excellent shear yield stress compared with chitosan suspension. The difference in behavior results from the difference in the conductivity of the chitosan and chitosan phosphate particles due to their degree of the polarizability. The shear stress for chitosan and chitosan phosphate suspensions showed a linear dependence on the volume fraction of particles. The values of structure factor, A s obtained 1 and 3~4 for chitosan and chitosan phosphate suspensions and it may be due to the formation of single-row chains and multiple chains upon application of the electric field. Throughtout the experimental results, chitosan and chitosan phosphate suspensions were shown to be an ER fluid.

scholarly journals Preliminary experimental evaluation of a novel loudspeaker featuring magnetorheological fluid surround absorber

2020 ◽  
Vol 17 (2) ◽  
pp. 922 ◽  
Author(s):  
Endra Dwi Purnomo ◽  
Ubaidillah Ubaidillah ◽  
Fitrian Imaduddin ◽  
Iwan Yahya ◽  
Saiful Amri Mazlan
Keyword(s):  
Magnetic Flux ◽  
Yield Stress ◽  
Experimental Evaluation ◽  
Flux Distribution ◽  
Magnetic Circuit ◽  
Experimental Result ◽  
The Finite Element Method ◽  
Shear Yield Stress ◽  
Shear Yield ◽  
Novel Design

<span>A novel design of magnetorheological fluids (MRF) based surround device in a loudspeaker system was studied in this article. The main objective of this research is to design a new surround device of the loudspeaker that can be easily controlled its damping. Therefore, it was predicted that the audio pressure level on the loudspeaker could be easily manipulated at a different sound source by applying a certain magnetic field. This function could not be reached using one conventional speaker system. Firstly, a set of an electromagnetic device containing MRF was designed to replace the conventional rubber surround. The magnetic circuit was then evaluated using the finite element method magnetics to study the flux distribution in the MRF area. The current was varied from 0.25 to 0.75 A by an interval of 0.25 A. The magnetic flux resulted from the simulation was then logged and used as the based value for predicting the change of shear yield stress. The base properties of the shear yield stress of the MRF against the magnetic flux was obtained from previous experimental result. Therefore, it was hopefully the prediction could be closed to the real system. Based on the simulation result, the shear yield stress varied from 43 to 49 Mpa or about 15 % increment. </span><span lang="IN">A simple experimental work was carried out. By applying particular direct current into the coil, the sound quality generated by the loudspeaker shows different values</span><span>.</span><span lang="IN"> Based on the preliminary experiment, the level of decibel decreased about 3 dB as the application of magnetic fields. The idea has been proven in this preliminary experimental evaluation.</span>

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