scholarly journals Simulation of Magnetodielectric Effect in Magnetorheological Elastomers

2019 ◽  
Vol 20 (6) ◽  
pp. 1457 ◽  
Author(s):  
Danil Isaev ◽  
Anna Semisalova ◽  
Yulia Alekhina ◽  
Liudmila Makarova ◽  
Nikolai Perov
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Particles ◽  
Effective Permittivity ◽  
Functional Materials ◽  
Magnetorheological Elastomers ◽  
Metallic Particles ◽  
Lognormal Size Distribution ◽  
Proposed Model ◽  
Magnetodielectric Effect

We present the results of numerical simulation of magnetodielectric effect (MDE) in magnetorheological elastomers (MRE)—the change of effective permittivity of elastomer placed under the external magnetic field. The computer model of effect is based on an assumption about the displacement of magnetic particles inside the elastic matrix under the external magnetic field and the formation of chain-like structures. Such displacement of metallic particles between the planes of capacitor leads to the change of capacity, which can be considered as a change of effective permittivity of elastomer caused by magnetic field (magnetodielectric effect). In the literature, mainly the 2D approach is used to model similar effects. In this paper, we present a new approach of magnetorheological elastomers simulation—a 3D-model of the magnetodielectric effect with ability to simulate systems of 10 5 particles. Within the framework of the model, three types of particle size distributions were simulated, which gives an advantage over previously reported approaches. Lognormal size distribution was shown to give better qualitative match of the modeling and experimental results than monosized type. The developed model resulted in a good qualitative agreement with all experimental data obtained earlier for Fe-based elastomers. The proposed model is useful to study these novel functional materials, analyze the features of magnetodielectric effect and predict the optimal composition of magnetorheological elastomers for further profound experimental study.

Study of the Performance of Practical Magneto-Rheological Elastomers

2012 ◽  
Vol 430-432 ◽  
pp. 1979-1983
Author(s):  
Wei Bang Feng ◽  
Xue Yang ◽  
Zhi Qiang Lv
Keyword(s):  
Magnetic Field ◽  
Mechanical Properties ◽  
Mechanical Property ◽  
Magnetic Properties ◽  
External Magnetic Field ◽  
Magnetic Particles ◽  
Poor Performance ◽  
Electrical And Magnetic Properties ◽  
Intelligent Material ◽  
Magneto Rheological

Magneto-rheological elastomer( MR elastomer) is an emerging intelligent material made up of macromolecule polymer and magnetic particles. While a promising wide application it has in the fields of warships vibration controlling for its controllable mechanical, electrical and magnetic properties by external magnetic field, design and application of devices based on it are facing great limitations imposed by its poor performance in mechanical properties and magneto effect. Aiming at developing a practical MR elastomer, a new confecting method was proposed in this paper. Then, following this new method and using a specificly designed solidifying matrix, an amido- polyester MR elastomer was developed with its mechanical property systemically explored.

scholarly journals Biomagnetic Recovery and Bioaccumulation of Selenium Granules in Magnetotactic Bacteria

2016 ◽  
Vol 82 (13) ◽  
pp. 3886-3891 ◽  
Author(s):  
Masayoshi Tanaka ◽  
William Knowles ◽  
Rosemary Brown ◽  
Nicole Hondow ◽  
Atsushi Arakaki ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Particles ◽  
Magnetotactic Bacteria ◽  
Selenium Nanoparticles ◽  
Water Remediation ◽  
Polluted Water ◽  
Contaminated Water ◽  
Elemental Selenium ◽  
Cell Recovery

ABSTRACTUsing microorganisms to remove waste and/or neutralize pollutants from contaminated water is attracting much attention due to the environmentally friendly nature of this methodology. However, cell recovery remains a bottleneck and a considerable challenge for the development of this process. Magnetotactic bacteria are a unique group of organisms that can be manipulated by an external magnetic field due to the presence of biogenic magnetite crystals formed within their cells. In this study, we demonstrated an account of accumulation and precipitation of amorphous elemental selenium nanoparticles within magnetotactic bacteria alongside and independent of magnetite crystal biomineralization when grown in a medium containing selenium oxyanion (SeO32−). Quantitative analysis shows that magnetotactic bacteria accumulate the largest amount of target molecules (Se) per cell compared with any other previously reported nonferrous metal/metalloid. For example, 2.4 and 174 times more Se is accumulated than Te taken up into cells and Cd2+adsorbed onto the cell surface, respectively. Crucially, the bacteria with high levels of Se accumulation were successfully recovered with an external magnetic field. The biomagnetic recovery and the effective accumulation of target elements demonstrate the potential for application in bioremediation of polluted water.IMPORTANCEThe development of a technique for effective environmental water remediation is urgently required across the globe. A biological remediation process of waste removal and/or neutralization of pollutant from contaminated water using microorganisms has great potential, but cell recovery remains a bottleneck. Magnetotactic bacteria synthesize magnetic particles within their cells, which can be recovered by a magnetic field. Herein, we report an example of accumulation and precipitation of amorphous elemental selenium nanoparticles within magnetotactic bacteria independent of magnetic particle synthesis. The cells were able to accumulate the largest amount of Se compared to other foreign elements. More importantly, the Se-accumulating bacteria were successfully recovered with an external magnetic field. We believe magnetotactic bacteria confer unique advantages of biomagnetic cell recovery and of Se accumulation, providing a new and effective methodology for bioremediation of polluted water.

MONITORING INTERPARTICLE DISTANCE IN MAGNETORHEOLOGICAL COMPOSITES

2007 ◽  
Vol 21 (28n29) ◽  
pp. 4868-4874
Author(s):  
G. BOSSIS ◽  
E. COQUELLE ◽  
C. NOEL ◽  
F. GIULIERI ◽  
A. M. CHAZE
Keyword(s):  
Magnetic Field ◽  
Liquid Crystal ◽  
Energy Dissipation ◽  
Viscoelastic Properties ◽  
Magnetic Particles ◽  
Interparticle Distance ◽  
Magnetorheological Elastomer ◽  
Magnetorheological Elastomers ◽  
Magnetic Spheres ◽  
The Creation

We describe two different systems, the first one based on a magnetorheological elastomer and the second one on magnetic particles inside a liquid crystal. In both system we manage to have chain structures with particles that are not in contact. The effect of the gap between particles on the viscoelastic properties are studied. We show in particular how in magnetorheological elastomers, the energy dissipation is closely related to the creation and the motion of cavities in the gap between the particles. In liquid crystal chaining of particles can occur without applying a magnetic field. This happens if the anchoring of liquid crystal on the surface of the particles is homeotropic. We demonstrate how the combination of elastic defects and of a magnetic field allow to obtain microscopic springs made of a pair of magnetic spheres.

Sensing Behavior of Magnetorheological Elastomers

2009 ◽  
Vol 131 (9) ◽  
Author(s):  
Xiaojie Wang ◽  
Faramarz Gordaninejad ◽  
Mert Calgar ◽  
Yanming Liu ◽  
Joko Sutrisno ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electrical Properties ◽  
Magnetic Particles ◽  
External Stimulus ◽  
Magnetorheological Elastomer ◽  
Polymer Medium ◽  
Mechanical Loads ◽  
Magnetorheological Elastomers ◽  
Impedance Response ◽  
Ferromagnetic Particles

A magnetorheological elastomer (MRE) is comprised of ferromagnetic particles aligned in a polymer medium by exposure to a magnetic field. The structures of the magnetic particles within elastomers are very sensitive to the external stimulus of either mechanical force or magnetic field, which result in multiresponse behaviors in a MRE. In this study, the sensing properties of MREs are investigated through experimentally characterizing the electrical properties of MRE materials and their interfaces with external stimulus (magnetic field or stress/strain). A phenomenological model is proposed to understand the impedance response of MREs under mechanical loads and magnetic fields. Results show that MRE samples exhibit significant changes in measured values of impedance and resistance in response to compressive deformation, as well as the applied magnetic field.

Effect of Magnetic Field on the Distribution and Orientation of Magnetic Particles in Co-injection Moulding

2008 ◽  
Vol 24 (4) ◽  
pp. 227-237 ◽  
Author(s):  
E.O. Ogur ◽  
M.C. Davis ◽  
V. Goodship ◽  
G.F. Smith
Keyword(s):  
Magnetic Field ◽  
Image Analysis ◽  
External Magnetic Field ◽  
Injection Moulding ◽  
Magnetic Particles ◽  
Magnetic Field Gradient ◽  
Analysis Techniques ◽  
Drag Forces ◽  
Nickel Particles ◽  
Image Analysis Techniques

This paper presents a study of the effect of an external magnetic field on the distribution and orientation of magnetic particles in co-injection moulding. The orientation of the magnetic particles was determined using optical microscopy and image analysis techniques. The external magnetic field was placed in the tool cavity and used to magnetize the particles and to generate the necessary magnetic field gradient to manipulate them. The ferromagnetic nickel particles remained magnetic enough to overcome the strong drag forces imposed on them by the polymeric fluid matrix and to be orientated by the permanent magnet in the tool.

scholarly journals Experimental Investigation of Magnetic Particle Movement in Two-Phase Vertical Flow under an External Magnetic Field Using 2D LIF-PIV

2020 ◽  
Vol 10 (11) ◽  
pp. 3976
Author(s):  
Changje Lee ◽  
Yong-Seok Choi
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Particles ◽  
Magnetic Particle ◽  
Two Phase Flow ◽  
Scattered Light ◽  
Laser Sheet ◽  
Phase Flow ◽  
Particle Movement ◽  
Two Phase

In this study, we experimentally investigated magnetic particle movement in two-phase flow under an external magnetic field. According to Faraday’s law, the alignment of a magnet is important for power generation. For high generation, it is important to understand how magnetic particles move in two-phase flow. The rotationality could be determined by observing a single particle; however, this is impossible due to the flow conditions. In this study, we estimated nonrotationality based on the vorticity. To eliminate scattered light and improve the signal-to-noise ratio, the laser-induced fluorescence particle image velocimetry technique was used. The solenoid nozzle has a hydraulic diameter of 3 mm. Its surface is covered with a coil with a diameter of 0.3 mm. The average diameter of a magnetic particle is 1.2 μm. The excitation and emission wavelengths are 532 and 612 nm, respectively. A thin laser sheet setup was configured. The laser sheet was illuminated on both sides to prevent shadows. The images were captured at 200 μm away from the wall and center of the nozzle. To estimate the decrease in vorticity, the theoretical and single-phase non-magnetic and magnetic particles are compared. The vorticity of magnetic particles is reduced by the external magnetic field.

Effect of the Concentration of the Magnetic Particles in the Ferrooil on its Dynamic’s Viscosity Changes in an External Magnetic Field

2015 ◽  
Vol 220-221 ◽  
pp. 324-327 ◽  
Author(s):  
Marcin Frycz ◽  
Wojciech Horak
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Tribological Properties ◽  
Dynamic Viscosity ◽  
Magnetic Particles ◽  
Magnetic Polarity ◽  
Journal Bearings ◽  
Physical Conditions ◽  
Viscosity Changes

There is presented an effect of the changes of the concentration of magnetic particles included in the ferrooil on the dynamic viscosity in the presence of external magnetic field in this paper. The study was conducted in the context of temperature’s changes. In that way, the influence of external physical conditions of ferrooil’s employment was also taken into account. Ferrooil’s dynamic viscosity changes significantly alter the tribological properties and thus its usefulness as a lubricant of the sliding journal bearings. Due to the fact that the ferrooil demonstrates strong magnetic polarity in the presence of an external magnetic field, it is possible to control the viscosity by means of an external magnetic field just by changing the intensity as well as by changing of the concentration of magnetic particles.The paper presents, in the form of graphs, the changes of ferrooil’s dynamic viscosity as a function of temperature and concentration of magnetic particles. The results of research were also subjected to analysis.

Characterization of optical trap for metallic particles using external magnetic field

2011 ◽  
Author(s):  
Vivek S. Jadhav ◽  
Wasim Sayyad ◽  
G. R. Kulkarni ◽  
B. M. Jaffar Ali
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Optical Trap ◽  
Metallic Particles
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