In the paper the novel soft magnetic composite system is investigated. A ferrofluid emulsion studied demonstrates the strong magnetic properties which are atypical for commonly known emulsions. Interaction of ferrofluid emulsions with a magnetic field is considered. Structural transformations in these media, such as deformation of emulsion microdroplets and emulsion inversion, are studied. The ...

Recent developments in gravitation theory indicate that the classic general relativity is an effective macroscopic theory which will be eventually replaced with a more fundamental theory based on thermodynamics of yet unknown microscopic degrees of freedom. Here we consider thermodynamics of an effective spacetime which may be formed under the influence of an external magnetic field in a cobalt...

This paper reports a new continuous-flow and label-free sorting scheme based on biocompatible ferrofluid hydrodynamics (ferrohydrodynamics) for the separation of mammalian cells (HeLa cells and mouse whole blood). Ferrofluids are stable magnetic nanoparticles suspensions used as sorting media in microfluidics for both particles and cells. Here we develop a biocompatible ferrofluid that can sust...

Integrated pumps and valves make up an essential part of most microfluidic devices and produce increased control in the device. Some existing micro-pumps and valves utilized in microfluidics involve electrical, pneumatic, and thermal actuation. However, electrical micro-pumps and valves generally entail a complicated and expensive fabrication process, and are limited to samples free of any ions...

We explore magnetic-field-induced ordering and microphase separation of aqueous ferrofluid and of aqueous mixtures of ferrofluid with nonmagnetic latex spheres. The ferrofluid is a surfactant stabilized aqueous suspension of magnetite (Fe3O4) particles with average diameter 20 nm (including the approximately 2.5-nm thick surfactant layer); the nonmagnetic latex spheres are charge stabilized pol...

We report on the fabrication and characterization of a single-mode fiber variable optical attenuator (VOA) based on a ferrofluid shutter actuated by a magnetic field created by a low voltage electromagnet. We compare the performance of a VOA using oil-based ferrofluid, with one VOA using water-based 12 ferrofluid, and demonstrate broadband optical attenuation of up to 28 dB with polarization de...

Ferrofluid spin-up flow is studiedwithin a sphere subjected to a uniform rotatingmagnetic field from two surrounding spherical coils carrying sinusoidally varying currents at right angles and 901 phase difference. Ultrasound velocimetry measurements in a full sphere of ferrofluid shows no measureable flow. There is significant bulk flow in a partially filled sphere (1–14 mm/s) of ferrofluid or ...

The radiation and magnetic field effects of nanofluids play a significant role in biomedical engineering medical treatment. This study investigated the performance gold particles blood flow (Sisko fluid flow) over porous, slippery, curved surface. partial slip effect was considered to examine characteristics nanofluid depth. foremost differential equations Sisko model were reduced ordinary by u...

We describe a convective instability of a stratified ferrofluid subject to a magnetic field. The ferrofluid is described as binary mixture featuring two important dimensionless numbers the barometric one B and the magnetic barometric one Bm. At the field strength, where the latter exceeds the former, instability sets in. We discuss the growth rate of linear perturbations and the amplitude of no...

The effect of magnetic anisotropy-axis alignment on the superparamagnetic (SPM) and superspin glass (SSG) states in a frozen ferrofluid has been investigated. The ferrofluid studied here consists of maghemite nanoparticles (γ-Fe2O3, mean diameter = 8.6 nm) dispersed in glycerine at a volume fraction of ~15%. In the high temperature SPM state, the magnetization of aligned ferrofluid increased by...