scholarly journals Extensional Magnetorheology of Viscoelastic Human Blood Analogues Loaded with Magnetic Particles

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6930
Author(s):  
João M. Nunes ◽  
Francisco J. Galindo-Rosales ◽  
Laura Campo-Deaño
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Human Blood ◽  
Magnetic Particles ◽  
Volume Fraction ◽  
Flow Direction ◽  
Deborah Number ◽  
Simultaneous Application ◽  
String Structure ◽  
Breakup Time

This study represents a pioneering work on the extensional magnetorheological properties of human blood analogue fluids loaded with magnetic microparticles. Dynabeads M-270 particles were dispersed in Newtonian and viscoelastic blood analogue fluids at 5% wt. Capillary breakup experiments were performed, with and without the influence of an external magnetic field aligned with the flow direction. The presence of the particles increased the viscosity of the fluid, and that increment was larger when embedded within a polymeric matrix. The application of an external magnetic field led to an even larger increment of the viscosity of the working fluids, as the formation of small aggregates induced an increment in the effective volume fraction of particles. Regarding the liquid bridge stability, the Newtonian blood analogue fluid remained as a Newtonian liquid exhibiting a pinch-off at the breakup time in any circumstance. However, in the case of the viscoelastic blood analogue fluid, the presence of the particles and the simultaneous application of the magnetic field enhanced the formation of the beads-on-a-string structure, as the Ohnesorge number remained basically unaltered, whereas the time of the experiment increased due to its larger viscosity, which resulted in a decrease in the Deborah Number. This result was confirmed with fluids containing larger concentrations of xanthan gum.

Ultrasonic Investigation of the Effect of Volume Fraction on the Clustering Structures of Magneto-Rheological Fluids

2010 ◽  
Vol 670 ◽  
pp. 198-206 ◽  
Author(s):  
M.A. Bramantya ◽  
H. Takuma ◽  
J. Kuroiwa ◽  
T. Sawada
Keyword(s):  
Magnetic Field ◽  
Wave Propagation ◽  
External Magnetic Field ◽  
Ultrasonic Wave ◽  
Propagation Velocity ◽  
Magnetic Particles ◽  
Volume Fraction ◽  
Wave Propagation Velocity ◽  
Ultrasonic Wave Propagation ◽  
Carrier Liquid

The rheological response of magnetorheological fluid (MRF) results from the polarization induced in the suspended particles by application of an external magnetic field. Characteristics of an MRF depend on the volume faction, that is the percentage of magnetic particles in the carrier liquid. We propose a qualitative investigation of these volume fraction effects by measuring properties of ultrasonic wave propagation velocity in MRFs having various volume fractions. The ultrasonic wave propagation velocity changes under the effect of an external magnetic field as a result of arrangement of clusters along the direction of the field in the MRF.

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.

Viscomagnetic Heat Flux Experiments as a Test of Gas Kinetic Theory in the Burnett Regime

1978 ◽  
Vol 33 (7) ◽  
pp. 749-760 ◽  
Author(s):  
G. E. J. Eggermont ◽  
P. W. Hermans ◽  
L. J. F. Hermans ◽  
H. F. P. Knaap ◽  
J. J. M. Beenakker
Keyword(s):  
Magnetic Field ◽  
Boundary Layer ◽  
Heat Flux ◽  
External Magnetic Field ◽  
Room Temperature ◽  
Flow Direction ◽  
Rectangular Channel ◽  
Gas Kinetic Theory ◽  
The Magnetic Field ◽  
Good Agreement

In a rarefied polyatomic gas streaming through a rectangular channel, an external magnetic field produces a heat flux perpendicular to the flow direction. Experiments on this “viscom agnetic heat flux” have been performed for CO, N2, CH4 and HD at room temperature, with different orientations of the magnetic field. Such measurements enable one to separate the boundary layer contribution from the purely bulk contribution by means of the theory recently developed by Vestner. Very good agreement is found between the experimentally determined bulk contribution and the theoretical Burnett value for CO, N2 and CH4 , yet the behavior of HD is found to be anomalous.

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.

Observation of soft glassy behavior in a magnetic colloid exposed to an external magnetic field

Soft Matter ◽  
2020 ◽  
Vol 16 (30) ◽  
pp. 7126-7136
Author(s):  
Sithara Vinod ◽  
Philip J. Camp ◽  
John Philip
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Applied Field ◽  
Uniform Magnetic Field ◽  
Volume Fraction ◽  
High Rate ◽  
Glassy Behavior ◽  
Low Volume

Microstructures (viewed in a direction perpendicular and parallel to the applied field) responsible for soft glassy behavior in a ferrofluid of low volume fraction when a uniform magnetic field is applied at a sufficiently high rate.

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.

PDF Evolution of Texture in the Fabrication of Magneto-Active Elastomers

2017 ◽  
Author(s):  
Manuel Aurelio Rodriguez ◽  
Paris von Lockette
Keyword(s):  
Magnetic Field ◽  
External Field ◽  
Potential Energy ◽  
Applied Field ◽  
Magnetic Particles ◽  
Volume Fraction ◽  
Magnetic Potential ◽  
Fabrication Process ◽  
Particle Distributions ◽  
Field Strengths

Magneto-Active elastomers (MAEs) and magneto-rheological elastomers (MREs) are smart materials that consist of hard and soft magnetic particles, respectively, embedded in a flexible matrix. Their actuation capabilities are dependent on the arrangement of particles achieved during the fabrication process. Previous works have shown varying degrees of particle alignment and / or agglomeration as a function of fabrication process variable, most notably volume fraction of the particulates, their magnetic material type (hard vs soft), and the strength of the external field applied during curing. In this work, we simulated the dynamics of magnetic particles suspended in a fluid matrix to predict the evolution of microstructures resulting from these varying process conditions. The simulations accounted for the magnetic interaction of all particles using standard dipole-dipole interaction potentials along with dipole-field potentials developed from the Zeeman Energy. Additionally, the field local to each particle, on which magnetization depends, was determined by the sum of the external fields generated by each member of the ensemble and their demagnetizing fields. Fluid drag forces and short range particle-particle repulsion (non-overlapping) were also considered. These interactions determined the body forces and torques acting on each particle that drove the system of equations of motions for the ensemble of particles. The simulation was carried out over a nearest neighbor periodic unit cell using an adaptive time stepping numerical integration scheme until an equilibrium structure was reached. Structural parameters, related to the magnetic energy, spatial distribution, spatial alignment, and orientation alignments of the particle distributions were defined to characterize the simulated structures. The effect of volume fraction and intensity of the external magnetic field on the achieved particle distributions were studied. At low external field strengths, the particles formed long entangled chains that had very low alignment with the applied field. The remnant magnetic potential energy of these configurations was also significantly low. As the field is increased the length of the chains reduced and the alignment increased. The corresponding change in magnetic potential energy of the system with an increase in the applied field was found to follow a power law fit that spanned a wide range of magnetic field strengths. At low volume fractions the particles aligned rapidly with the field and formed short chains. As the volume fraction of the samples increased the chains grew longer and closer to each other, and magnetic potential of the structure became lower. Results of the simulations suggest that it is possible to tailor the microstructure and thus affect remanent magnetization and magnetization anisotropy, by judicious control of process parameters. This ability could have implications for newly emerging additive manufacturing techniques utilizing suspensions of magnetic particulates.

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