Dependence of the Viscosity of Magnetic Fluids on the Concentration of Magnetic Particles, Temperature, and a Magnetic Field

2021 ◽  
Vol 95 (10) ◽  
pp. 2141-2147
Author(s):  
A. K. Zaripov ◽  
A. Ubaidi
Keyword(s):  
Magnetic Field ◽  
Magnetic Particles ◽  
Magnetic Fluids

Theoretical Modeling and Simulations of Magnetic Fluids in Gradient Magnetic Fields

2010 ◽  
Vol 146-147 ◽  
pp. 1510-1513
Author(s):  
Xiao Ling Peng ◽  
Xiao Yang ◽  
Hai Biao Wei ◽  
Rui Ping Yue ◽  
Hong Liang Ge
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Field Gradient ◽  
Magnetic Particles ◽  
Magnetic Field Gradient ◽  
Magnetic Fluids ◽  
Gradient Distribution ◽  
Particle Distributions ◽  
The Right ◽  
Pulsed Fields

When a magnetic field is applied to magnetic fluids (MF), various structures of MF are formed: chain-like structures in low fields, columnar, lamellar and striped structures in high fields, ellipsoidal structures in pulsed fields, and layered structures in rotating fields. The inner structures and particle distributions of MF in gradient magnetic fields are quite interesting, but very few works have been done on this. In the present study, the effects of magnetic field gradient on the structures of MF are investigated using a two-dimensional Monte Carlo simulation. The results show that a gradient distribution of magnetic particles is formed under gradient magnetic fields. Moreover, with increasing the field gradient, more magnetic particles are pushed to the right region and particle distribution changes from grass-like clusters to needle-like ones.

Magnetoviscous Effects In Ferrofluids

2000 ◽  
Vol 10 (4) ◽  
pp. 178-184 ◽  
Author(s):  
S. Odenbach
Keyword(s):  
Magnetic Field ◽  
Magnetic Particles ◽  
Magnetic Fluids ◽  
Experimental Methods ◽  
The State ◽  
Theoretical Research ◽  
Sedimentation Stability ◽  
Nanometer Range ◽  
Microscopic Models

Abstract Suspensions of magnetic particles with diameters in the nanometer range exhibit longterm sedimentation stability as well as the possibility of magnetic field induced control of their properties and flow. One of the most famous field induced effects is the change of viscosity of the fluids due to the action of magnetic influences. An explanation of these effects on basis of microscopic models is a challenging field of actual experimental and theoretical research. Within this article the state of knowledge on magnetoviscous effects in magnetic fluids will be summarized and in particular the experimental methods used to obtain related results will be discussed.

Influence of the Magnetic Interaction among Particles on Distributions of Magnetic Fluids Using Computer Simulations

2010 ◽  
Vol 150-151 ◽  
pp. 1595-1598
Author(s):  
Xiao Ling Peng ◽  
Hai Biao Wei ◽  
Xiao Yang ◽  
Rui Ping Yue ◽  
Hong Liang Ge
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Magnetic Particles ◽  
Particle Distribution ◽  
Magnetic Field Gradient ◽  
Magnetic Interaction ◽  
Magnetic Fluids ◽  
Colloidal Dispersion ◽  
Gradient Distribution ◽  
Particle Distributions

Magnetic fluid is a stable colloidal dispersion of ferromagnetic particles in a liquid carrier. Once a magnetic field is applied to magnetic fluids (MF), various structures of MF are formed. A detailed understanding of structures and particle distributions in gradient magnetic fields is much important. But very few works have been done on this. In the present study, the effects of magnetic field gradient and magnetic interaction among magnetic particles on the structures of MF are investigated using a two-dimensional Monte Carlo simulation. The results show that a gradient distribution of magnetic particles is formed under gradient magnetic fields. However, as the interaction between magnetic particles increases, the distribution gradient decreases, accompanied by the formation of chain-like clusters. Moreover, with increasing the magnetic interaction, particle distribution changes from grass-like clusters to needle-like ones.

Analysis of magneto rheological elastomers for energy harvesting systems

2020 ◽  
Vol 64 (1-4) ◽  
pp. 439-446
Author(s):  
Gildas Diguet ◽  
Gael Sebald ◽  
Masami Nakano ◽  
Mickaël Lallart ◽  
Jean-Yves Cavaillé
Keyword(s):  
Magnetic Field ◽  
Energy Harvesting ◽  
Shear Strain ◽  
Magnetic Induction ◽  
Magnetic Particles ◽  
Homogeneous Magnetic Field ◽  
Electrical Signal ◽  
Harvesting Systems ◽  
Dc Bias ◽  
Magneto Rheological

Magneto Rheological Elastomers (MREs) are composite materials based on an elastomer filled by magnetic particles. Anisotropic MRE can be easily manufactured by curing the material under homogeneous magnetic field which creates column of particles. The magnetic and elastic properties are actually coupled making these MREs suitable for energy conversion. From these remarkable properties, an energy harvesting device is considered through the application of a DC bias magnetic induction on two MREs as a metal piece is applying an AC shear strain on them. Such strain therefore changes the permeabilities of the elastomers, hence generating an AC magnetic induction which can be converted into AC electrical signal with the help of a coil. The device is simulated with a Finite Element Method software to examine the effect of the MRE parameters, the DC bias magnetic induction and applied shear strain (amplitude and frequency) on the resulting electrical signal.

scholarly journals Optical Imaging of Magnetic Particle Cluster Oscillation and Rotation in Glycerol

2021 ◽  
Vol 7 (5) ◽  
pp. 82
Author(s):  
River Gassen ◽  
Dennis Thompkins ◽  
Austin Routt ◽  
Philippe Jones ◽  
Meghan Smith ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Magnetic Particles ◽  
Magnetic Particle ◽  
Barium Hexaferrite ◽  
Optical Microscope ◽  
Simplified Model ◽  
Particle Cluster ◽  
Average Deviation ◽  
Cross Sectional

Magnetic particles have been evaluated for their biomedical applications as a drug delivery system to treat asthma and other lung diseases. In this study, ferromagnetic barium hexaferrite (BaFe12O19) and iron oxide (Fe3O4) particles were suspended in water or glycerol, as glycerol can be 1000 times more viscous than water. The particle concentration was 2.50 mg/mL for BaFe12O19 particle clusters and 1.00 mg/mL for Fe3O4 particle clusters. The magnetic particle cluster cross-sectional area ranged from 15 to 1000 μμm2, and the particle cluster diameter ranged from 5 to 45 μμm. The magnetic particle clusters were exposed to oscillating or rotating magnetic fields and imaged with an optical microscope. The oscillation frequency of the applied magnetic fields, which was created by homemade wire spools inserted into an optical microscope, ranged from 10 to 180 Hz. The magnetic field magnitudes varied from 0.25 to 9 mT. The minimum magnetic field required for particle cluster rotation or oscillation in glycerol was experimentally measured at different frequencies. The results are in qualitative agreement with a simplified model for single-domain magnetic particles, with an average deviation from the model of 1.7 ± 1.3. The observed difference may be accounted for by the fact that our simplified model does not include effects on particle cluster motion caused by randomly oriented domains in multi-domain magnetic particle clusters, irregular particle cluster size, or magnetic anisotropy, among other effects.

Magnetorheological fluid based on amorphous Fe-Si-B alloy magnetic particles

2021 ◽  
pp. 1045389X2110643
Author(s):  
Chuncheng Yang ◽  
Zhong Liu ◽  
Xiangyu Pei ◽  
Cuiling Jin ◽  
Mengchun Yu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Rheological Property ◽  
Magnetic Particles ◽  
Annealing Treatment ◽  
Magnetorheological Fluid ◽  
The Stability ◽  
The Magnetic Field ◽  
Amorphous Particle ◽  
Better Than

Magnetorheological fluids (MRFs) based on amorphous Fe-Si-B alloy magnetic particles were prepared. The influence of annealing treatment on stability and rheological property of MRFs was investigated. The saturation magnetization ( Ms) of amorphous Fe-Si-B particles after annealing at 550°C is 131.5 emu/g, which is higher than that of amorphous Fe-Si-B particles without annealing. Moreover, the stability of MRF with annealed amorphous Fe-Si-B particles is better than that of MRF without annealed amorphous Fe-Si-B particles. Stearic acid at 3 wt% was added to the MRF2 to enhance the fluid stability to greater than 90%. In addition, the rheological properties demonstrate that the prepared amorphous particle MRF shows relatively strong magnetic responsiveness, especially when the magnetic field strength reaches 365 kA/m. As the magnetic field intensified, the yield stress increased dramatically and followed the Herschel-Bulkley model.

THE ROTATIONAL EFFECT OF MAGNETIC PARTICLES ON CELLULAR APOPTOSIS BASED ON FOUR ELECTROMAGNET FEEDBACK CONTROL SYSTEM

2021 ◽  
pp. 2150045
Author(s):  
Jia Ji Lee ◽  
Chang Hong Pua ◽  
Misni Misran ◽  
Poh Foong Lee
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Field ◽  
Control System ◽  
Feedback Control ◽  
Cell Apoptosis ◽  
Magnetic Particles ◽  
Drug Carriers ◽  
Feedback Control System ◽  
Rotational Effect ◽  
Dynamic Magnetic Field

Objectives: Magnetic drug targeting offers the latest popular alternative option to deliver magnetic drug carriers into targeting region body parts through manipulation of an external magnetic field. However, the effectiveness of using an electromagnetic field to manipulate and directing magnetic particles is yet to be established. Methods: In this paper, a homemade cost-effective electromagnet system was built for the purpose of studying the control and directing the magnetic drug carriers. The electromagnet system was built with four electromagnetic sources and tested the capability in directing the particles’ movement in different geometry patterns. Besides that, the creation of the self-rotation of individual magnetic particle clusters was achieved by using fast switching between magnetic fields. This self-rotation allows the possibility of cell apoptosis study to carry out. The system was constructed with four electromagnets integrated with a feedback control system and built to manipulate a droplet of commercially available iron (II, III) oxide nanoparticles to steer the magnetic droplet along different arbitrary trajectories (square, circle, triangle, slanted line) in 2-dimensional. Results: A dynamic magnetic field of 25 Hz was induced for magnetic nanoparticles rotational effect to observe the cell apoptosis. A profound outcome shows that the declining cell viability of the cell lines by 40% and the morphology of shrinking cells after the exposure of the dynamic magnetic field. Conclusion: The outcome from the pilot study gives an idea on the laboratory setup serves as a fundamental model for studying the electromagnetic field strength in applying mechanical force to target and to rotate for apoptosis on cancer cell line study.

scholarly journals Tunable Adhesion of a Bio-Inspired Micropillar Arrayed Surface Actuated by a Magnetic Field

2018 ◽  
Vol 86 (1) ◽  
Author(s):  
Xingji Li ◽  
Zhilong Peng ◽  
Yazheng Yang ◽  
Shaohua Chen
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Magnetic Particles ◽  
Rotation Angle ◽  
Adhesion Force ◽  
Practical Applications ◽  
Section Shape ◽  
Theoretical Predictions ◽  
Large Elastic Deformation ◽  
The Difference

Bio-inspired functional surfaces attract many research interests due to the promising applications. In this paper, tunable adhesion of a bio-inspired micropillar arrayed surface actuated by a magnetic field is investigated theoretically in order to disclose the mechanical mechanism of changeable adhesion and the influencing factors. Each polydimethylsiloxane (PDMS) micropillar reinforced by uniformly distributed magnetic particles is assumed to be a cantilever beam. The beam's large elastic deformation is obtained under an externally magnetic field. Specially, the rotation angle of the pillar's end is predicted, which shows an essential effect on the changeable adhesion of the micropillar arrayed surface. The larger the strength of the applied magnetic field, the larger the rotation angle of the pillar's end will be, yielding a decreasing adhesion force of the micropillar arrayed surface. The difference of adhesion force tuned by the applied magnetic field can be a few orders of magnitude, which leads to controllable adhesion of such a micropillar arrayed surface. Influences of each pillar's cross section shape, size, intervals between neighboring pillars, and the distribution pattern on the adhesion force are further analyzed. The theoretical predictions are qualitatively well consistent with the experimental measurements. The present theoretical results should be helpful not only for the understanding of mechanical mechanism of tunable adhesion of micropillar arrayed surface under a magnetic field but also for further precise and optimal design of such an adhesion-controllable bio-inspired surface in future practical applications.

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