Boundary effect in electrorheological fluids

Gong, Xinglong; Yang, Fan; Xuan, Shouhu; Zong, Luhang; Zhu, Wei; Jiang, Wanquan

doi:10.1103/physreve.84.061505

Cited by 7 publications

(6 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Understanding the influence of boundaries on particle dynamics is of great significance, from both a fundamental and an applied point of view [1][2][3][4][5][6][7][8][9]. For example, blood cells moving in vessels, particles migrating in porous media, and macromolecules diffusing in membranes are all affected by the presence of boundaries.…”

Section: Introductionmentioning

confidence: 99%

Broadband boundary effects on Brownian motion

Simha

Raizen

2015

Phys. Rev. E

View full text Add to dashboard Cite

Brownian motion of particles in confined fluids is important for many applications, yet the effects of the boundary over a wide range of time scales are still not well understood. We report high-bandwidth, comprehensive measurements of Brownian motion of an optically trapped micrometer-sized silica sphere in water near an approximately flat wall. At short distances we observe anisotropic Brownian motion with respect to the wall. We find that surface confinement not only occurs in the long time scale diffusive regime but also in the short time scale ballistic regime, and the velocity autocorrelation function of the Brownian particle decays faster than that of a particle in bulk fluid. Furthermore, at low frequencies the thermal force loses its color due to the reflected flow from the no-slip boundary. The power spectrum of the thermal force on the particle near a no-slip boundary becomes flat at low frequencies. This detailed understanding of boundary effects on Brownian motion opens a door to developing a 3D microscope using particles as remote sensors.

show abstract

Section: Introductionmentioning

confidence: 99%

Broadband boundary effects on Brownian motion

Simha

Raizen

2015

Phys. Rev. E

View full text Add to dashboard Cite

show abstract

“…For the boundary particles, the friction force between the boundary particles and the electrodes is expressed as (Gong et al, 2011)…”

Section: Modelmentioning

confidence: 99%

Dielectric relaxation effect on flow behavior of electrorheological fluids

Wang

Gong

Yang

et al. 2014

Journal of Intelligent Material Systems and Structures

View full text Add to dashboard Cite

The dielectric relaxation effect on the flow behavior of electrorheological fluids under dynamic shear was studied. The flow curves of electrorheological fluids in the dynamic state were simulated with shear rates from 0.1 to 1000 s 21 under different relaxation times. When the magnitude of the relaxation time is smaller than 10 22 s, the break shear rate changes little at different relaxation times. But the break shear rate changes obviously when the magnitude of the relaxation time is larger than 10 22 s. To further understand the influence of the relaxation time, Sr/Ba-doped TiO 2 electrorheological fluids were prepared and their dielectric properties and flow curves under shear flow were tested. The relaxation time of the electrorheological fluid is influenced by the Sr/Ti mole ratio but not the Ba/Ti mole ratio, and the electrorheological effects of the fluids were highly influenced by varying the Sr/Ti mole ratios. The experimental results agreed well with the above computer simulation. Finally, a possible mechanism was proposed to explain the effect of dielectric relaxation on flow behavior of electrorheological fluids.

show abstract

“…Wang et al explored the cactus‐like TiO 2 /kaolinite particle based ER fluids and claimed that the friction between adjacent particles could be responsible for the improvement of their ER properties . Gong et al have proposed the effect of the boundary friction coefficient on the rheological properties of the ER fluids by simulation . Besides, the experimental results proposed by Jaeger and co‐workers indicated that applying larger normal stress can enhance the yield stress of the ER fluids, which indirectly confirmed the influence of friction force on the ER behaviors .…”

Section: Introductionmentioning

confidence: 99%

Elegant Surface of CoNi Alloys toward Efficient Magnetorheological Performances Realized with Carbon Quantum Dots

Zhang

Tian

et al. 2018

Adv Materials Inter

View full text Add to dashboard Cite

of superwetting surfaces. [3,4] Up to now, many methods have been developed to produce superhydrophobic surface via creating rough structures or attaching small particles on the surface through various strategies. [5][6][7] Nowadays, transition metals cobalt (Co) and nickel (Ni) and their bimetallic alloys are of great interest on account of their unique and desirable properties, such as high values of saturation magnetization (M s ), excellent mechanical strength, and facile synthesis routes. [8,9] The CoNi alloys have been used in many fields, such as catalysis, microwave absorption, biomedical devices, and magnetic resonance imaging. [10][11][12] In general, the applications of CoNi alloys depend on two factors: chemical composition and morphology, which determine their intrinsic magnetic moment, magnetic permeability, and wettability. In general, Co-rich CoNi alloys possess high values of M s . Stimuli control of magnetic particles is a challenge for basic research, whereas it is a promising way for advanced applications. In contrast to conventional carbonyl iron particles, Co, Ni, and their bimetallic alloys provide a viable alternative for magnetorheological (MR) materials owning to their high values of M s and good controllability for their morphology.MR fluids are a kind of intelligent materials, which usually consist of micrometer-sized magnetizable particles dispersed in a liquid media. [13][14][15] When exposed to an external magnetic field, the dispersed particles get magnetized and develop magnetic moments, which give rise to strong magnetostatic attraction between adjacent particles and consequently build up aligned fiber-like structures. [15,16] The resulting field-induced structures hinder the free flow of the former Newtonian fluid, and high values of the yield stress and viscosity are observed, which is called MR effect. [17] Applications based on MR fluids, such as couplings, actuators, clutches, and vibration dampers, employ the shearing and squeezing strength of MR fluids. [18][19][20] The hottest topics on MR fluids are finding ways to improve their yield stress, stability upon settling, and activity over a wide temperature range. Current fundamental research on MR fluids mainly focuses on the alleviation of settling issues for MR suspensions, which may restrict their use in practical applications. To achieve this goal, several promising strategies Designing and fabricating a rational surface architecture is one of the critical factors to achieve desirable physical and chemical properties and still remains an immense challenge. Herein, a series of CoNi-based hierarchical microspheres with different surface morphologies, including litchi-like, seed-of-plane-tree-like, and waxberry-like shapes, are obtained via surface nucleation of carbon quantum dots (CQDs) with different concentrations in liquid polyol. Microstructure investigations suggest that all the CoNi microspheres are uniformly with enhanced surface roughness with the increasing concentration of CQDs. This study provides insight into...

show abstract

Boundary effect in electrorheological fluids

Cited by 7 publications

References 27 publications

Broadband boundary effects on Brownian motion

Broadband boundary effects on Brownian motion

Dielectric relaxation effect on flow behavior of electrorheological fluids

Elegant Surface of CoNi Alloys toward Efficient Magnetorheological Performances Realized with Carbon Quantum Dots

Contact Info

Product

Resources

About