Biomedical subjects

Mark I Shliomis

Publications and source records attributed to Mark I Shliomis.

4 recordsLinked to original sources

PubMed2006

Ferrofluidic torsional pendulum driven by oscillating magnetic field.

A thin disk-shaped container filled with a ferrofluid and suspended in a horizontal linearly polarized ac magnetic field can perform torsional vibrations around its vertical diameter. In contrast to a recently studied spherical pendulum, the cell is sensitive to the field direction: It exposes its edge to the stationary or slowly oscillating magnetic field, and its broad side to the field of a high frequency. When the amplitude of the latter field is increased, the state of rest gets destabilized, yielding to oscillations near the equilibrium. Further growth of the field strength results in the onset of the cell rotation. We describe sequences of local and global bifurcations which accompany those transitions.

Journal Article↗

PubMed2005

Onset of convection in colloids stratified by gravity.

Settling of the equilibrium (barometric) distribution of colloidal grains in a liquid requires a very long time in comparison with that necessary for temperature equilibrium establishment. This mismatch enables different scenarios for the onset of thermal convection. If the stratified state has had no time to be settled, the colloid behaves as a pure fluid where only stationary convection arises. On the contrary, if the barometric concentration profile has been reached before the temperature gradient is imposed, only oscillatory convection occurs. Thereafter, the oscillations last as long as it takes the convection to wash away the initial concentration profile. Then the fluid becomes homogeneous and stationary convection is eventually established. The influence of the Soret effect upon the onset of convection is also taken into account and discussed.

Journal Article↗

PubMed2004

Nonlinear dynamics of a ferrofluid pendulum.

A ferrofluid torsion pendulum in an oscillating magnetic field exhibits a rich variety of nonlinear self-oscillatory regimes. The dynamics is governed by the system of coupled differential equations for the in- and off-axis components of the fluid magnetization and the pendulum angular deflection. In the limiting case of high driving frequency, the system reduces to the sole Rayleigh-type equation. Much more complicated temporal patterns arise when the field frequency and the pendulum eigen frequency are of the same order.

Journal Article↗

PubMed2003

Comment on "Structure of ferrofluid dynamics".

We compare known equations for ferrofluid magnetization with a recently proposed rectified Debye theory [H. W. Müller and M. Liu, Phys. Rev. E 64, 061405 (2001)] and demonstrate that the latter is unsatisfactory. Derived by a purely formal method, it contains numerous unknown parameters, fails to explain previous experiments, and has no heuristic force.

Comment↗