Regular and chaotic dynamics of a fountain in a stratified fluid.

In the present paper, we study by direct numerical simulation (DNS) and theoretical analysis, the dynamics of a fountain penetrating a pycnocline (a sharp density interface) in a density-stratified fluid. A circular, laminar jet flow of neutral buoyancy is considered, which propagates vertically upwards towards the pycnocline level, penetrates a distance into the layer of lighter fluid, and further stagnates and flows down under gravity around the up-flowing core thus creating a fountain. The DNS results show that if the Froude number (Fr) is small enough, the fountain top remains axisymmetric and steady.

[Computer-controlled maintenance of the dissolved oxygen level in a medium during controlled cultivation of Neisseria meningitidis].

A new method for controlling the processes of N. meningitidis cultivation by the content of oxygen dissolved in the medium with the use of a computer, including the software, technical and methodological provision of the computer-operated control system, has been developed. The processes of the cultivation of N.

[The criterion of cell division synchronization for assessing the stressor exposure of a Salmonella typhi population].

Criterion of the synchronization (CS) of cells division for S. typhi population is proposed. The criterion is based on the assumption of the normal distribution of cells with different generation time in the population after stressor (shock) action.

Dynamics of particles in the steady flows of an inviscid fluid.

Advection of small particles with inertia in two-dimensional ideal flows is studied both numerically and analytically. It is assumed that the flow disturbance around the particle corresponds to a potential dipole, so that the motion is driven by pressure gradient, inertial, and added-mass forces. It is found that in general the motion is nonintegrable, but particular exact solutions can be obtained.