A Physical Basis for Stability in Bimodal Dispersions Including Micrometer-sized Particles and Nanoparticles using Both Linear and Non-linear Models to Describe Yield

Burguera, Elena F.; Love, Brian J.; Sahul, Raffi; Ngatu, Grum T.; Wereley, Norman M.

doi:10.1177/1045389x07086692

Cited by 18 publications

(10 citation statements)

References 16 publications

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“…Similar results were seen by Park et al (2009). Burguera et al (2008) found that yield stress decreased with increasing concentration of nanoparticles, although stability improved. Fang et al (2009) have studied the effect of carbon nanotubes on sedimentation stability and yield stress.…”

Section: Introductionsupporting

confidence: 82%

Rheology of Perfluorinated Polyether-based MR Fluids with Nanoparticles

Jónsdóttir

Gudmundsson

Dijkman

et al. 2010

Journal of Intelligent Material Systems and Structures

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Motivated by the use of magneto-rheological (MR) technology in prosthetic devices, the goal of this study is to develop a MR fluid composition that is tailored for the requirements of a prosthetic knee actuator. A MR fluid composition is sought with a suitable balance between the field-induced shear stress, the off-state viscosity, and sedimentation stability for the proposed application. Rheological characteristics are investigated for samples with monodisperse micron-sized particles and bidisperse fluids with a mixture of micron- and nanosized particles. Two types of nanosized particles are used. All fluid samples employ a novel perfluorinated polyether oil as carrier liquid which enhances stability. The samples are investigated with respect to both field-induced and off-state characteristics. The results are compared to analytical and empirical models that exist in the literature. The monodisperse fluids are shown to give a favorable trade-off between field-induced strength and off-state viscosity. The addition of a small concentration of nanoparticles is found to moderately increase the field-induced shear-yield stress. However, for a larger concentration of nanoparticles, the yield stress begins to decrease. Nanoparticles exhibit an undesirable effect on the off-state viscosity. The results reveal valuable information for the designers of MR fluids and designers of prosthetic actuators.

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Section: Introductionsupporting

confidence: 82%

Rheology of Perfluorinated Polyether-based MR Fluids with Nanoparticles

Jónsdóttir

Gudmundsson

Dijkman

et al. 2010

Journal of Intelligent Material Systems and Structures

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“…However, during on-state which by applying current 4 A or equivalent to 658 mT, the viscosity of MRGN is higher than that of MRGs. As expected, this phenomenon is due to the nanoparticles γ-Fe2O3 had attached and filled the interspaces between the micron-sized particles when the magnetic field is applied [12,13]. Thus, the formation of regular and compact chains structure in the MRGN is attained, indirectly, enhance the MR performance.…”

Section: Fig 2 Comparison Of Magnetic Properties Between Mrgs and Msupporting

confidence: 53%

Improvement of magnetorheological greases with superparamagnetic nanoparticles

Mohamad

Mazlan

Choi

et al. 2018

MATEC Web of Conferences

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Magnetorheological greases (MRGs) is a viscoelastic suspension comprised of carbonyl iron (CI) particles in a thixotropic medium; grease, which able to solve the instability problem that occurs in oil medium like MRFs. The primary purpose introduction of superparamagnetic nanoparticles γ-Fe2O3 in MRGs suspension is to investigate the effect of additives toward MRGs characteristics. Two types of MRGs suspension with and without nanoparticles γ-Fe2O3 were prepared in the same CI particles concentration for comparison purpose. It was observed that MRGs with incorporated of 1 wt% nanoparticles γ-Fe2O3 showed an increment regarding magnetic properties. In the meantime, the off-state viscosity of MRGs containing nanoparticles γ-Fe2O3 was reduced, however, increased during on-state condition. This fact indicates that the interspaces between CI particles are filled by the nanoparticles γ-Fe2O3. Therefore, the introduction of the nanoparticles indirectly improved the MRGs properties.

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“…Under static conditions, the experimental results are in concordance with those provided by the Bingham model. On the other hand, Burguera et al [84] and Wang and Gordaninejad [85] used the Hershel-Bulkey model to accommodate fluids showing post-yield shear thinning and shear thickening. In this model, the constant post-yield plastic viscosity in the Bingham model is replaced with a low power model that is dependent on the shear rate.…”

Section: Rheological Characteristicsmentioning

confidence: 98%