Introduction. The extraction of directed motion from random fluctuations is an old and controversial problem in statistical mechanics with a long and interesting history [1]. Although excluded by the second law of thermodynamics for equilibrium systems, rectification of fluctuations is possible in systems driven sufficiently far away from thermal equilibrium [2, 3]. The problem has gained renew...

Ferrofluids are stable colloidal suspensions of nanosize ferromagnetic particles in either an aqueous or an oil-based solvent1. In the presence of a magnetic field gradient within a ferrofluid, magnetic forces and torque are developed to drive magnetic particles, which subsequently draw along the liquid solvent carrier. This allows continuous actuation and precise positioning of the ferrofluid ...

We study the equilibrium structure of large but finite aggregates of magnetic dipoles, representing a colloidal suspension of magnetite particles in a ferrofluid. With increasing system size, the structural motif evolves from chains and rings to multi-chain and multi-ring assemblies. Very large systems form single- and multi-wall coils, tubes and scrolls. These structural changes result from a ...

We exploit magnetostriction in polydisperse ferrofluids in order to generate nonlinear responses and apply a thermodynamical method to derive the desired nonlinear magnetic susceptibility. For an ideal gas, this method has been demonstrated to be in excellent agreement with a statistical method. In the presence of a sinusoidal ac magnetic field, the magnetization of the polydisperse ferrofluid ...

We present an OUI that combines Hall Effect sensing and actuation through electromagnetically-manipulated ferrofluid. The movement of magnets worn on the fingertips, over a surface embedded with a Hall Effect sensor array and electromagnets, gives the user the ability to interact with ferrofluid. This system provides a three-dimensional, physically animated response, as well as three-dimensiona...

Linear and non-linear surface waves on a ferrofluid cylinder surrounding a current-carrying wire are investigated. Suppressing the Rayleigh-Plateau instability of the fluid column by the magnetic field of a sufficiently large current in the wire axis-symmetric surface deformations are shown to propagate without dispersion in the long wavelength limit. Using multiple scale perturbation theory th...

Among a variety of hyperthermia methods, magnetic nanoparticle hyperthermia is a highly promising approach for its confined heating within the tumour. In this study we perform in vivo animal experiments on implanted prostatic tumours in mice to measure temperature distribution in the tumour during magnetic nanoparticle hyperthermia. Temperature elevations are induced by a commercially available...

In this paper the development of an inertial sensor for vibration measurements based on the use of ferrofluids is presented. The use of ferrofluids as inertial mass offers advantages over traditional devices like robustness against inertial shocks and performances controllable via electrical signals; moreover, ferrofluids density and other physical features can be controlled by an external magn...

We report a novel magnetic-field-assisted method for the fabrication and manipulation of nonspherical polymer particles within a ferrofluid-based droplet microfluidic device. Shape control and chain assembly of droplets with tunable lengths have been achieved.