Magnetic field of a dipole and the dipole–dipole interaction

Kraftmakher, Yaakov

doi:10.1088/0143-0807/28/3/003

Cited by 46 publications

(27 citation statements)

References 12 publications

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“…The first term on the right hand side accounts for the conservative force, where U(x) is the potential energy of the pendulum 16 shown in Fig.2: In fig. 1 we can easily identify three different regimes: 1) Large Δ,…”

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confidence: 99%

Nonlinear Energy Harvesting

2009

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Ambient energy harvesting has been in recent years the recurring object of a number of research efforts aimed at providing an autonomous solution to the powering of small-scale electronic mobile devices. Among the different solutions, vibration energy harvesting has played a major role due to the almost universal presence of mechanical vibrations. Here we propose a new method based on the exploitation of the dynamical features of stochastic nonlinear oscillators. Such a method is shown to outperform standard linear oscillators and to overcome some of the most severe limitations of present approaches. We demonstrate the superior performances of this method by applying it to piezoelectric energy harvesting from ambient vibration.

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confidence: 99%

Nonlinear Energy Harvesting

2009

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“…They have validated their model for the case in which the surfaces of the two particles are in contact with each other. Recently, Castaner et al [8], Gayetsky and Caylor [9], Kraftmakher [10] and PintoEspinoza [11] have further investigated the dipole-dipole interaction in a uniform magnetic field.…”

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confidence: 99%

Interaction forces between soft magnetic particles in uniform and non-uniform magnetic fields

et al. 2010

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The influence of the magnetization of a soft magnetic sphere on the surrounding magnetic field is measured and characterized. The interaction force between two soft magnetic particles is directly measured using an ultra precision load sensor in uniform and non-uniform magnetic fields. The interaction force largely follows an inverse fourth power law as a function of separation distance between particle centers. At small distances, the effect of magnetization of one particle on the magnetization of its adjacent particle causes the attractive (repulsive) force to be larger (smaller) than that predicted by the inverse fourth power law. The theoretical prediction based on a modified dipole model, that takes into account the coupling effect of the magnetization among soft magnetic particles, gives excellent agreement with the measured force in a uniform magnetic field. The interaction force under a non-uniform applied magnetic field can be reasonably predicted using the dipole-dipole interaction model when the local magnetic field is used to determine the magnetization.

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“…where R l is the equivalent resistance, C l is the equivalent capacitance and 1/( R l C l ) = 0.01, and θ = 1250 is the piezoelectric coupling coefficient in the measured circuit. The transverse magnetic force (in the z -direction) is determined from the force between two magnetic dipoles (Kraftmakher, 2007)…”

Section: Theoretical Simulationsmentioning

confidence: 99%

Enhanced stochastic, subharmonic, and ultraharmonic energy harvesting

Lin

Walsh

Alphenaar

2012

Journal of Intelligent Material Systems and Structures

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Nonlinear bistable systems have been shown to provide improved efficiency for harvesting energy from random and broadband vibration sources. This article explores the distinct frequency response in the broadened spectrum of a particular nonlinear energy harvester, a piezoelectric cantilever with magnetic coupling. The cantilever response evolves dynamically with frequency around the main cantilever resonance. Both stochastic and multifrequency vibration responses are observed and account for some of the improved efficiency. In addition, subharmonics and ultraharmonics of the main resonance, along with various combinations of these, appear. An analytical model of the bistable dynamics produces results consistent with those observed experimentally. Overall, four distinct types of efficiency improvements appear, in which the signal is amplified above the noncoupled cantilever response: (a) ultraharmonic amplification below resonance frequency, (b) stochastic amplifications in multifrequency and multiamplitude oscillations, (c) ultrasubharmonic amplification, and (d) subharmonic amplification. Taken together, the stochastic, subharmonic, and ultraharmonic responses produce an average of threefold to fivefold increase in voltage production.

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Magnetic field of a dipole and the dipole–dipole interaction

Cited by 46 publications

References 12 publications

Nonlinear Energy Harvesting

Nonlinear Energy Harvesting

Interaction forces between soft magnetic particles in uniform and non-uniform magnetic fields

Enhanced stochastic, subharmonic, and ultraharmonic energy harvesting

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