scholarly journals Magnetically Actuated Artificial Microswimmers as Mobile Microparticle Manipulators

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Jake Buzhardt ◽  
Phanindra Tallapragada
Keyword(s):  
Magnetic Field ◽  
Critical Frequency ◽  
Rotating Magnetic Field ◽  
Mobile Manipulators ◽  
Magnetically Actuated ◽  
Constant Strength ◽  
Fluid Environment ◽  
Controlled Motion ◽  
The Magnetic Field ◽  
Two Bodies

Abstract Microscale swimming robots have been envisaged for many biomedical applications such as targeted drug delivery, where the microrobot will be expected to navigate in a fluid environment while carrying a payload. We show that such a payload does not have to be physically bound to the swimmer, but may be instead manipulated by the microrobot through hydrodynamic interaction. We consider a magnetically actuated artificial microswimmer, whose locomotion induces a disturbance velocity field in the fluid, which moves a cargo particle in its vicinity. The problem investigated in this paper is therefore one of coupled locomotion-manipulation of two bodies in a fluid. The swimmer is actuated by a uniform, rotating magnetic field of constant strength leading to net motion in the direction perpendicular to the plane of rotation if the frequency associated with the periodic magnetic field is above a critical frequency. Below this critical frequency, the swimmer tumbles in place without net locomotion. Controlled motion of the particle and swimmer is achieved by switching the planes of rotation of the magnetic field and the frequency of the magnetic field above and below the critical frequency. The results of this paper show that microswimmers can be utilized as mobile manipulators of microparticles in a fluid.

ORIENTATION DYNAMICS OF MAGNETORHEOLOGICAL FLUIDS SUBJECT TO ROTATING EXTERNAL FIELDS

2001 ◽  
Vol 15 (06n07) ◽  
pp. 758-766 ◽  
Author(s):  
SONIA MELLE ◽  
MIGUEL A. RUBIO ◽  
GERALD G. FULLER
Keyword(s):  
Magnetic Field ◽  
Light Scattering ◽  
Simple Model ◽  
Critical Frequency ◽  
Optical Methods ◽  
Phase Lag ◽  
Rotating Magnetic Fields ◽  
Mr Fluids ◽  
Small Angle Light Scattering ◽  
The Magnetic Field

The formation and orientation of field-induced structures in magnetorheological (MR) fluids subject to rotating magnetic fields have been studied using two optical methods: scattering dichroism and small angle light scattering (SALS). The SALS patterns show how these chain-like aggregates follow the magnetic field with the same frequency but with a retarded phase angle for all the frequencies measured. Using scattering dichroism two different behaviors for both, dichroism and phase lag, are found below or above a critical frequency. Experimental results have been reproduced by a simple model considering the torques balance on the chain-like aggregates.

Swirling Flow of Magnetic Fluid in Multi-Pole Rotating Magnetic Field

2003 ◽  
Author(s):  
Kenichi Kamioka ◽  
Ryuichiro Yamane
Keyword(s):  
Magnetic Field ◽  
Fluid Flow ◽  
Circular Cylinder ◽  
Phase Velocity ◽  
Magnetic Fluid ◽  
Swirling Flow ◽  
Peak Velocity ◽  
Rotating Magnetic Field ◽  
Outer Periphery ◽  
The Magnetic Field

The experiments are conducted on the magnetic fluid flow induced by the multi-pole rotating magnetic field in a circular cylinder. The numbers of poles are two, four, six, eight and twelve. The applied electric current and frequency are 2∼6 A and 20∼60 Hz, respectively. The peak velocity of the flow increases with the increase in the strength and the phase velocity of the magnetic field. As the increase in the number of poles, the flow shifts to the outer periphery.

scholarly journals Investigation of mixing time in liquid under influence of rotating magnetic field

2017 ◽  
Vol 38 (4) ◽  
pp. 555-565
Author(s):  
Alicja Przybył ◽  
Rafał Rakoczy ◽  
Maciej Konopacki ◽  
Marian Kordas ◽  
Radosław Drozd ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Experimental Investigation ◽  
Reynolds Number ◽  
Mixing Time ◽  
Rotating Magnetic Field ◽  
Homogenization Time ◽  
Set Up ◽  
The Relationship ◽  
The Magnetic Field

Abstract The aim of the study was to present an experimental investigation of the influence of the RMF on mixing time. The obtained results suggest that the homogenization time for the tested experimental set-up depending on the frequency of the RMF can be worked out by means of the relationship between the dimensionless mixing time number and the Reynolds number. It was shown that the magnetic field can be applied successfully to mixing liquids.

Spin reorientation transition: phase diagrams and entropy change

2011 ◽  
Vol 1310 ◽  
Author(s):  
Vittorio Basso ◽  
Carlo P. Sasso ◽  
Michaela Kuepferling
Keyword(s):  
Magnetic Field ◽  
Easy Axis ◽  
Entropy Change ◽  
Rotating Magnetic Field ◽  
Spin Reorientation ◽  
Temperature Dependent ◽  
First Order ◽  
Crystalline Anisotropy ◽  
The Magnetic Field ◽  
Magneto Crystalline Anisotropy

ABSTRACTIn this paper we review the phase diagram and derive the entropy change for spin reorientation transitions by considering first order magnetization process theory with temperature dependent magneto-crystalline anisotropy constants. We derive the magnetic field-induced entropy change Δs for a transition between easy axis and easy plane, showing that for alternating magnetic field, Δs has a change of sign at the reorientation temperature, while for rotating magnetic field its sign is definite. We apply the model to CoZn W-type barium ferrite.

Waves in a cold plasma with spatially periodic sheared fields

1989 ◽  
Vol 42 (1) ◽  
pp. 153-164 ◽  
Author(s):  
D. A. Diver ◽  
E. W. Laing ◽  
C. C. Sellar
Keyword(s):  
Magnetic Field ◽  
Wave Propagation ◽  
Cold Plasma ◽  
Density Fluctuations ◽  
Rotating Magnetic Field ◽  
Physical Parameters ◽  
Order Ordinary Differential Equation ◽  
Spatially Periodic ◽  
Constant Magnitude ◽  
The Magnetic Field

We have studied wave propagation in a cold plasma, in the presence of a spatially rotating magnetic field of constant magnitude. New features introduced by this variation include streaming velocities and a plasma current in equilibrium and density fluctuations. We present only the case of wave propagation along the axis of rotation of the magnetic field. A set of ordinary differential equations for the electric field components is obtained, which may be combined into a single fourth-order ordinary differential equation with periodic coefficients. Solutions are obtained in closed form and their nature is determined in terms of the physical parameters of the System, magnetic field strength, number density and wave frequency.

Band structure for relativistic charge carriers submitted to a helical magnetic field

2021 ◽  
pp. 2150141
Author(s):  
D. Martínez ◽  
J. A. Reyes ◽  
G. Reyes ◽  
C. G. Avendaño
Keyword(s):  
Magnetic Field ◽  
Band Structure ◽  
Charge Carriers ◽  
Momentum Operator ◽  
Rotating Magnetic Field ◽  
Band Gaps ◽  
Spatial Period ◽  
System Parameters ◽  
Helical Magnetic Field ◽  
The Magnetic Field

In this paper, we consider a clockwise rotating magnetic field around the [Formula: see text]-axis and charge carriers which impinge normally to the [Formula: see text] plane. We obtained analytically the spectrum of the momentum operator [Formula: see text] and found the existence of a band structure from which the movement of these charge carries is filtered according to the spatial period of the magnetic field or its intensity. Also we exhibit the existence of three band gaps (one total or primary and two partials) whose width depends on the system parameters.

SHOT NOISE OF ELECTRON PAIRS IN NONCYCLIC AND NON-ADIABATIC MAGNETIC FIELD

2007 ◽  
Vol 21 (17) ◽  
pp. 3065-3074
Author(s):  
XIAN-JUN YE
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Shot Noise ◽  
Beam Splitter ◽  
Rotating Magnetic Field ◽  
Triplet States ◽  
Electron Pairs ◽  
Singlet And Triplet States ◽  
The Magnetic Field ◽  
Symmetric Properties

By adding a rotating magnetic field in one incoming lead, we calculate the shot noise with different incident states in a 4-lead beam-splitter. The result shows that the shot noise of singlet and triplet states oscillates with the external magnetic field and depends on the symmetric properties of the incident states. Thus, the singlet, entangled triplet, and polarized states can be distinguished by adjusting the magnetic field.

scholarly journals A Magnetically Actuated Drug Delivery System for Robotic Endoscopic Capsules

2015 ◽  
Vol 10 (1) ◽  
Author(s):  
Fredy Munoz ◽  
Gursel Alici ◽  
Weihua Li
Keyword(s):  
Magnetic Field ◽  
Drug Delivery ◽  
Drug Delivery System ◽  
Delivery System ◽  
Optimization Method ◽  
Analytical Models ◽  
Magnetically Actuated ◽  
Controlled Drug Delivery System ◽  
The Magnetic Field ◽  
Crank Mechanism

There is an increasing need to incorporate an actively controlled drug delivery system (DDS) into the next generation of capsule endoscopy in order to treat diseases in the gastrointestinal tract in a noninvasive way. Despite a number of attempts to magnetically actuate drug delivery mechanisms embedded in endoscopic capsules, longer operating distances and further miniaturization of on-board components are still drawbacks of such systems. In this paper, we propose an innovative magnetic system that consists of an array of magnets, which activates a DDS, based on an overly miniaturized slider–crank mechanism. We use analytical models to compare the magnetic fields generated by cylindrical and arc-shaped magnets. Our experimental results, which are in agreement with the analytical results, show that an optimally configured array of the magnets enhances the magnetic field and also the driving magnetic torque and subsequently, it imposes a high enough force on the piston of the DDS to expel a required dose of a drug out of a reservoir. We conclude that the proposed magnetic field optimization method is effective in establishing an active DDS that is designed to deliver drug profiles with accurate control of the release rate, release amount, and number of doses.

ON THE APPLICATION OF PLASMA KINETIC THEORY TO IONIC SOUND-WAVE EXPERIMENTS IN MAGNETIC FIELDS

1965 ◽  
Vol 43 (10) ◽  
pp. 1750-1765 ◽  
Author(s):  
M. J. Haggerty
Keyword(s):  
Magnetic Field ◽  
Uniform Magnetic Field ◽  
Critical Frequency ◽  
Magnetic Field Intensity ◽  
Sound Waves ◽  
Cyclotron Radius ◽  
The Mean ◽  
The Magnetic Field ◽  
Theoretical Results

The kinetic theoretical results for a homogeneous plasma in a uniform magnetic field are discussed qualitatively. The role of the mean cyclotron radius as a natural long-range cutoff is clarified. A relationship between a critical frequency for ionic sound waves and the magnetic-field intensity is predicted.

Study of an aluminium mixing system based on permanent magnets

2020 ◽  
Vol 39 (1) ◽  
pp. 192-197
Author(s):  
Andrey Morev ◽  
Alexander Aliferov
Keyword(s):  
Magnetic Field ◽  
Permanent Magnets ◽  
Rotation Velocity ◽  
Rotating Magnetic Field ◽  
The Finite Element Method ◽  
Ansys Software ◽  
Angular Rotation ◽  
Content Type ◽  
Maximum Value ◽  
The Magnetic Field

Purpose The purpose of this paper is to investigate the effect of the rotating magnetic field of permanent magnets on the aluminium melt bath. Design/methodology/approach This model was developed in the ANSYS software package and is based on the application of the finite element method and finite volume. Findings The distribution of the velocity of the melt in a cylindrical vertical bath and the dependence of the maximum value of the melt displacement on the angular rotation velocity of the system of permanent magnets is obtained. Originality/value This work focusses on the interaction of the magnetic field of the moving magnets with the molten metal.

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