Convective current experiments using Dakon-P equipment onboard “Progress” cargo spacecraft

In order to conduct experiments to study convection under microgravity it is proposed to use the “Progress” cargo transportation spacecraft. This is due to the fact that the microgravity environment onboard the Russian Segment (RS) of the ISS is not favorable, since the ISS center of mass is in the US segment, while many onboard systems generating micro-accelerations are installed in the ISS RS. There is no crew and no life support systems onboard the cargo spacecraft and micro-accelerations in it are significantly lower than those in the ISS RS. Passive modes of the cargo spacecraft attitude control are particularly favorable for carrying out microgravity experiments in space. In the course of a series of experiments conducted onboard a cargo spacecraft to find the minimal level of residual micro-accelerations, the gravity orientation mode turned out to be the most suitable one. It is planned to conduct an experiment to study convective isothermal currents using the Dakon-P scientific gear specifically developed for this purpose onboard “Progress” spacecraft in free flight in the gravity orientation mode.

The influence of convective current generator on the global current

The mathematical generalization of classical model of the global circuit with taking into account the convective current generator, working in the planetary boundary layer was considered. Convective current generator may be interpreted as generator, in which the electromotive force is generated by processes, of the turbulent transport of electrical charge. It is shown that the average potential of ionosphere is defined not only by the thunderstorm current generators, working at the present moment, but by the convective current generator also. The influence of the convective processes in the boundary layer on the electrical parameters of the atmosphere is not only local, but has global character as well. The numerical estimations, made for the case of the convective-unstable boundary layer demonstrate that the increase of the average potential of ionosphere may be of the order of 10% to 40%.

Variation of Sidestream Gas Formation during the Smoking Cycle

External contour distributions for gas temperatures and for the concentrations of carbon monoxide, carbon dioxide, hydrogen and oxygen are reported at successive times in the smoking cycle. The sidestream gases leave the coal in a vertical column centering at about 3 mm in front of the paper burn line. The levels of oxygen and the carbon oxides outside the coal are not primarily determined by any diffusion gradient originating in the inner coal. Rather, the external levels are determined partly by a convective current set up by the hot coal, and influenced by buoyancy effects. The oxygen in the convection stream forms the oxides of carbon on the hot surface of the coal, and the convected air is transported around the coal in an upwards direction. On the other hand, the hydrogen levels outside the coal result from diffusion from the inner coal, although much of this outward diffusing hydrogen is oxidised to water on the surface of the coal. The visible sidestream smoke column is about 3 mm in diameter and its centre is about 5 mm behind the sidestream gas column, becoming visible when the temperatures in the gas column are below about 150°C. The vapour which eventually condenses to form mainstream and sidestream smoke is released in the general pyrolysis / distillation region of the cigarette, just behind the paper burn line. Some of this vapour diffuses to the outside of the cigarette, through the partially degraded paper, and it condenses to form the sidestream smoke particles once outside the coal.