FLEXIBLE FERROMAGNETIC FILAMENTS AS ARTIFICIAL CILIA

The model of an artificial cilia as a flexible ferromagnetic filament in a rotating magnetic field is proposed. Numerical algorithm for the simulation of its behavior is developed and the characteristic shapes of the filament with one fixed end under the action of a rotating field are found. It is concluded that ferromagnetic filaments may be used as mixers in microfluidics.

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An experimental investigation of current production by means of rotating magnetic fields

Journal of Plasma Physics ◽

10.1017/s0022377800010850 ◽

1981 ◽

Vol 26 (3) ◽

pp. 465-480 ◽

Cited By ~ 34

Author(s):

W. N. Hugrass ◽

I. R. Jones ◽

M. G. R. Phillips

Keyword(s):

Magnetic Field ◽

Experimental Investigation ◽

Threshold Value ◽

Rotating Magnetic Field ◽

Electron Current ◽

Rotating Magnetic Fields ◽

Theta Pinch ◽

Current Production ◽

Made In ◽

Rotating Field

An investigation of current production by means of a rotating magnetic field is made in an experiment in which the technique is used to generate a theta-pinch- like distribution of field and plasma. Detailed measurements are made of both the generated unidirectional azimuthal electron current and the penetration of the rotating field into the plasma. The experimental results support the theoretical prediction that a threshold value of the amplitude of the applied rotating field exists for setting the electrons into rotation.

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3D motion of flexible ferromagnetic filaments under a rotating magnetic field

Soft Matter ◽

10.1039/d0sm00403k ◽

2020 ◽

Vol 16 (18) ◽

pp. 4477-4483 ◽

Cited By ~ 2

Author(s):

Abdelqader Zaben ◽

Guntars Kitenbergs ◽

Andrejs Cēbers

Keyword(s):

Magnetic Field ◽

Numerical Study ◽

Rotating Magnetic Field ◽

3D Motion ◽

Rotating Field

Experimental and numerical study of flexible ferromagnetic filaments reveal different regimes, when subjected to a 2D rotating field. The filaments were found to have a 3D motion at higher frequencies.

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Cylindrical plasma equilibria maintained by means of a rotating magnetic field

Journal of Plasma Physics ◽

10.1017/s0022377800000337 ◽

1982 ◽

Vol 28 (2) ◽

pp. 369-378 ◽

Cited By ~ 40

Author(s):

W. N. Hugrass

Keyword(s):

Magnetic Field ◽

Axial Magnetic Field ◽

Fluid Model ◽

Radial Electric Field ◽

Azimuthal Velocity ◽

Transverse Magnetic ◽

Rotating Magnetic Field ◽

Two Fluid Model ◽

Image Position ◽

Rotating Field

The equilibrium of a plasma cylinder confined by means of a steady axial magnetic field, Bα, and a transverse magnetic field, Bω, which rotates about the axis of the cylinder is analysed using a two-fluid model. It is shown that the electron fluid is tied to the rotating field provided that The rotating field does not impart a steady azimuthal motion to the ions provided that However, the ion fluid acquires a steady azimuthal velocity due to electron-ion collisions. A self-consistent radial electric field is produced; this field plays an important role in establishing the steady ion flow.

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Analytical solutions for the current driven by a rotating magnetic field in a spherical plasma

Journal of Plasma Physics ◽

10.1017/s0022377800016111 ◽

1991 ◽

Vol 46 (2) ◽

pp. 271-298 ◽

Cited By ~ 4

Author(s):

Peter A. Watterson

Keyword(s):

Magnetic Field ◽

Analytical Solutions ◽

Rotation Frequency ◽

Axial Current ◽

Rotating Magnetic Field ◽

Ohmic Dissipation ◽

Field Magnitude ◽

Synchronous Rotation ◽

Spherical Plasma ◽

Rotating Field

The steady currents driven in a spherical plasma by a rotating magnetic field via the Hall effect are studied analytically. The total field is shown to be symmetric across the origin. Integral relationships are obtained between Ohmic dissipation, angular momentum and the oscillating axial current density. The topology of the sum of a Hill's vortex field and a rotating field is documented. Analytical solutions for the driven current are obtained by expansion for the limits corresponding to small rotation frequency, to small number density, to large rotating-field magnitude, to small resistivity, and to small rotating-field magnitude combined with very small resistivity. The latter solution, relevant to the reactor limit, indicates that, with control of the vertical field magnitude, an MHD equilibrium can be generated with total current any fraction of the currentcorresponding to synchronous rotation of the electrons. Oscillating currents sufficient to drive the synchronous current are determined.

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Power and Momentum Relations in Rotating Magnetic Field Current Drive

Australian Journal of Physics ◽

10.1071/ph840509 ◽

1984 ◽

Vol 37 (5) ◽

pp. 509 ◽

Cited By ~ 13

Author(s):

WN Hugrass

Keyword(s):

Magnetic Field ◽

Angular Momentum ◽

Magnetic Fields ◽

Phase Velocity ◽

Current Drive ◽

Rotating Magnetic Field ◽

Plasma Current ◽

Rotating Magnetic Fields ◽

Frequency Source ◽

Rotating Field

The use of rotating magnetic fields (RMF) to drive steady currents in plasmas involves a transfer of energy and angular momentum from the radio frequency source feeding the rotating field coils to the plasma. The. power-torque relationships in RMF systems are discussed and the analogy between RMF current drive and the polyphase induction motor is explained. The general relationship between the energy and angular momentum transfer is utilized to calculate the efficiency of the RMF plasma current drive. It is found that relatively high efficiencies can be achieved in RMF current drive because of the low phase velocity and small slip between the rotating field and the electron fluid.

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Microfluidic propulsion by the metachronal beating of magnetic artificial cilia: a numerical analysis

Journal of Fluid Mechanics ◽

10.1017/jfm.2011.355 ◽

2011 ◽

Vol 688 ◽

pp. 44-65 ◽

Cited By ~ 52

Author(s):

S. N. Khaderi ◽

J. M. J. den Toonder ◽

P. R. Onck

Keyword(s):

Magnetic Field ◽

Fluid Flow ◽

Phase Difference ◽

Rotating Magnetic Field ◽

Artificial Cilia ◽

Discrete Nature ◽

Recovery Stroke ◽

Physical Interactions ◽

Metachronal Waves ◽

Considerable Enhancement

AbstractIn this work we study the effect of metachronal waves on the flow created by magnetically driven plate-like artificial cilia in microchannels using numerical simulations. The simulations are performed using a coupled magneto-mechanical solid–fluid computational model that captures the physical interactions between the fluid flow, ciliary deformation and applied magnetic field. When a rotating magnetic field is applied to super-paramagnetic artificial cilia, they mimic the asymmetric motion of natural cilia, consisting of an effective and recovery stroke. When a phase difference is prescribed between neighbouring cilia, metachronal waves develop. Due to the discrete nature of the cilia, the metachronal waves change direction when the phase difference becomes sufficiently large, resulting in antiplectic as well as symplectic metachrony. We show that the fluid flow created by the artificial cilia is significantly enhanced in the presence of metachronal waves and that the fluid flow becomes unidirectional. Antiplectic metachrony is observed to lead to a considerable enhancement in flow compared to symplectic metachrony, when the cilia spacing is small. Obstruction of flow in the direction of the effective stroke for the case of symplectic metachrony was found to be the key mechanism that governs this effect.

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Effect of a Rotating Magnetic Field on the Tilting Instability of a Prolate Rotamak

Australian Journal of Physics ◽

10.1071/ph890379 ◽

1989 ◽

Vol 42 (4) ◽

pp. 379 ◽

Cited By ~ 1

Author(s):

WK Bertram

Keyword(s):

Magnetic Field ◽

Equilibrium Model ◽

Rotating Magnetic Field ◽

Ideal Magnetohydrodynamics ◽

The Stability ◽

Rotating Field

The effect of a rotating magnetic field on the stability of a rotamak is investigated. Using a simple equilibrium model and the linearised equations of ideal magnetohydrodynamics, it is shown that a rotating field can be a contributing factor in the stabilisation of the tilting instability of a slightly prolate rotamak plasma.

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