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.

scholarly journals Investigation on Finishing Characteristics of Magnetic Abrasive Finishing Process Using an Alternating Magnetic Field

Machines ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 75
Author(s):  
Huijun Xie ◽  
Yanhua Zou
Keyword(s):  
Magnetic Field ◽  
Magnetic Particles ◽  
Alternating Magnetic Field ◽  
Surface Finishing ◽  
Magnetic Cluster ◽  
Magnetic Abrasive Finishing ◽  
Square Wave ◽  
Finishing Process ◽  
Abrasive Finishing ◽  
The Difference

The magnetic abrasive finishing (MAF) process is an ultra-precision surface finishing process. In order to further improve the finishing efficiency and surface quality, the MAF process using an alternating magnetic field was proposed in the previous research, and it was proven that the alternating magnetic field has advantages compared with the static magnetic field. In order to further develop the process, this study investigated the effect on finishing characteristics when the alternating current waveform is a square wave. The difference between the fluctuation behavior of the magnetic cluster in two alternating magnetic fields (sine wave and square wave) is observed and analyzed. Through analysis, it can be concluded that the use of a square wave can make the magnetic cluster fluctuate faster, and as the size of the magnetic particles decreases, the difference between the magnetic cluster fluctuation speed of the two waveforms is greater. The experimental results show that the surface roughness of SUS304 stainless steel plate improves from 328 nm Ra to 14 nm Ra within 40 min.

scholarly journals Quantifying the motion of magnetic particles in excised tissue: Effect of particle properties and applied magnetic field

2015 ◽  
Vol 393 ◽  
pp. 243-252 ◽  
Author(s):  
Sandip Kulkarni ◽  
Bharath Ramaswamy ◽  
Emily Horton ◽  
Sruthi Gangapuram ◽  
Alek Nacev ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Magnetic Particles ◽  
Particle Properties ◽  
Excised Tissue ◽  
Tissue Effect

Effect of a magnetic field on the fluorescence produced in irradiated anthracene solutions

1977 ◽  
Vol 55 (11) ◽  
pp. 2093-2101 ◽  
Author(s):  
R. S. Dixon ◽  
F. P. Sargent ◽  
V. J. Lopata ◽  
E. M. Gardy ◽  
B. Brocklehurst
Keyword(s):  
Magnetic Field ◽  
Fluorescence Intensity ◽  
Applied Magnetic Field ◽  
High Field ◽  
Spin Correlation ◽  
Hydrocarbon Solvents ◽  
Theoretical Predictions ◽  
High Fields ◽  
Ion Recombination ◽  
Gamma Irradiated

The effect of an applied magnetic field on the fluorescence from radiolytic ion recombination has been studied for anthracene in some hydrocarbon solvents. In pulse-irradiated anthracene (10−2 mol dm−3) in squalane, the fluorescence intensity following the pulse increases as a function of applied magnetic field in the range studied, 0 to 0.3 T (0 to 3000 G). At a constant magnetic field strength, the field-induced enhancement of the fluorescence intensity varies with time after the pulse. At high field strengths (0.3 T) the enhancement reaches a maximum of ∼45% about 50 ns after the pulse. Similar effects are observed in cyclohexane but the enhancement is smaller than that in squalane. In benzene solutions the effect is extremely small. These findings are confirmed by observations in continuously gamma-irradiated solutions. In gamma-irradiated solutions of anthracene (10−2 mol dm−3) in squalane, the fluorescence intensity increases with increasing magnetic field and approaches ∼13% enhancement at high fields (>0.1 T). The enhancement is smaller (∼3%) in cyclohexane and very small (<1%) in benzene solutions. 9,10-Dimethylanthracene gives a larger enhancement and anthracene-d10 a smaller enhancement than the parent anthracene at high fields. The results are in general agreement with recent theoretical predictions based on the effect of a magnetic field on the loss of spin correlation of geminate ions pairs prior to recombination.

ASTROID CURVES FOR A SYNTHETIC ANTIFERROMAGNETIC STACK IN AN APPLIED MAGNETIC FIELD

2009 ◽  
Vol 23 (20n21) ◽  
pp. 4021-4040
Author(s):  
D. M. FORRESTER ◽  
E. KOVACS ◽  
K. E. KÜRTEN ◽  
F. V. KUSMARTSEV
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Single Particle ◽  
Material Properties ◽  
Magnetic Particles ◽  
Particle System ◽  
Energy Landscape ◽  
Metastable States ◽  
Field Plane ◽  
The Magnetic Field

The interaction of two magnetic particles separated by an interlayer is illustrated through the "astroid" curves that represent regions in the magnetic field plane where different numbers of minima associated with stable or metastable states may exist. For a single particle, we describe the astroid curves of the Stoner-Wohlfarth model. The case of two particles is then examined and found to be much more complicated. The energy landscape of the two-particle system contains ferromagnetic, antiferromagnetic and canting states that emerge in response to the level of applied magnetic field. Because of this, up to four energy minima can exist in the system, depending upon the strength of the magnetic field and the material properties of the particles.

Classical spin dynamics of anisotropic Heisenberg dimmers

Open Physics ◽  
2013 ◽  
Vol 11 (12) ◽  
Author(s):  
Laura Pérez ◽  
Omar Suarez ◽  
David Laroze ◽  
Hector Mancini
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Magnetic Particles ◽  
Spin Dynamics ◽  
Dynamical Behavior ◽  
Exchange Constant ◽  
Largest Lyapunov Exponent ◽  
Lifshitz Equation ◽  
Dissipative Case ◽  
Complicated Topology

AbstractIn the present work we study the deterministic spin dynamics of two interacting anisotropic magnetic particles in the presence of an external magnetic field using the Landau-Lifshitz equation. The interaction between particles is through the exchange energy. We study both conservative and dissipative cases. In the first one, we characterize the dynamical behavior of the system by monitoring the Lyapunov exponents and bifurcation diagrams. In particular, we explore the dependence of the largest Lyapunov exponent respect to the magnitude of applied magnetic field and exchange constant. We find that the system presents multiple transitions between regular and chaotic behaviors. We show that the dynamical phases display a very complicated topology of intricately intermingled chaotic and regular regions. In the dissipative case, we calculate the final saturation states as a function of the magnitude of the applied magnetic field, exchange constant as well as the anisotropy constants.

Non-Equilibrium Magnetization of a Dilute Suspension of Magnetic Particles

2009 ◽  
Vol 152-153 ◽  
pp. 167-170 ◽  
Author(s):  
Alexander Tyatyushkin
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Heat Generation ◽  
Applied Magnetic Field ◽  
Single Particle ◽  
Uniform Magnetic Field ◽  
Magnetic Particles ◽  
Equilibrium Magnetization ◽  
Dilute Suspension ◽  
Generation Power

A suspension of magnetic particles in a viscous liquid magnetized in an alternating uniform magnetic field is theoretically studied. The suspension is regarded as so dilute that interaction of a single particle with the applied magnetic field can be considered without taking into account the influence of other particles. The complex magnetic susceptibility of the suspension is found as a function of the frequency of the applied magnetic field. The heat generation power density averaged over the period of the oscillations is calculated.

scholarly journals Simulation Study on the Motion of Magnetic Particles in Silicone Rubber-Based Magnetorheological Elastomers

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Zhiqiang Xu ◽  
Heng Wu ◽  
Qiuliang Wang ◽  
Liyin Yi ◽  
Jun Wang
Keyword(s):  
Magnetic Field ◽  
Silicone Rubber ◽  
Applied Magnetic Field ◽  
Magnetic Particles ◽  
Equations Of Motion ◽  
Viscous Force ◽  
The Finite Element Method ◽  
Magnetic Field Model ◽  
Magnetorheological Effect

Magnetorheological elastomer (MRE) is an intelligent composite material and has been widely used in various fields such as vibration reduction and sensing. MRE has an excellent magnetorheological effect through the chaining of its internal magnetic particles. Current studies on MREs mainly focus on the preparation of materials and characterization of mechanical properties. However, very few studies have been conducted on the mechanism of magnetic particle motion during MRE curing. Based on the silicone rubber-based MRE, the motion mechanism of magnetic particles during curing was explored through numerical simulation. First, we analyzed the magnetic force and viscous force of magnetic particles in MRE and discussed the equations of motion of magnetic particles under applied magnetic field. Further, we established a uniform magnetic field model through the finite element method and simulated the motion of two magnetic particles under the magnetic field. Finally, we discussed the effects of particle distribution angles, particle radii, applied magnetic field strength, and distance between particles on particle velocity and displacement. The results show that the distance between particles has the greatest influence on the motion of magnetic particles, and the size of the distance between particles will affect the contact time of the particles, thus affecting the chain formation of magnetic particles in the MRE.

Visco-elastic control of elastomer with magnetic particles by applied magnetic field

2016 ◽  
Vol 2016 (0) ◽  
pp. J2230204
Author(s):  
Daiki MAEDE ◽  
Fujio TSUMORI ◽  
Kentaro KUDO ◽  
Toshiko OSADA
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Magnetic Particles

scholarly journals High-speed transport of liquid droplets in magnetic tubular microactuators

2018 ◽  
Vol 4 (12) ◽  
pp. eaau8767 ◽  
Author(s):  
Wenwei Lei ◽  
Guanglei Hou ◽  
Mingjie Liu ◽  
Qinfeng Rong ◽  
Yichao Xu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Capillary Force ◽  
High Speed ◽  
Magnetic Particles ◽  
Liquid Droplets ◽  
Open Surface ◽  
Liquid Motion ◽  
Practical Applications ◽  
Closed Tube ◽  
Droplet Splitting

Magnetic field–induced droplet actuation has attracted substantial research interest in recent years. However, current magnetic-controlled liquids depend primarily on magnetic particles added to a droplet, which serves as the actuator on an open surface. These liquids inevitably suffer from droplet splitting with the magnetic particles or disengaging with the magnet, possibly leading to sample contamination, which severely limits their transport speed and practical applications. Here, we report a simple and additive-free method to fabricate magnetic tubular microactuators for manipulating liquid droplets by magnetism-induced asymmetric deformation, which generates an adjustable capillary force to propel liquids. These magnetic tubular microactuators can drive various liquid droplets with controllable velocity and direction. A speed of 10 cm s−1can be achieved, representing the highest speed of liquid motion driven by an external stimulus–induced capillary force in a closed tube found so far.

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