“Electrical wind” in CO2–laser mixtures at superatmospheric pressures

This article presents the results of “electrical wind” investigations in CO2–laser mixtures at superatmospheric (1–12 atm) pressures. It is established that for a fixed value of the unipolar corona discharge current, the gas flow velocity does not depend on the pressure, but is determined by the chemical composition of the working mixture. The maximum values of the “electrical wind” velocity are achieved in carbon dioxide and molecular nitrogen and their values are 3.2 and 2.9 ms−1. In typical laser mixtures CO2:N2:He = 1:1:1 – 1:1:3 the velocity of the “electrical wind ” are in the range from 2.5 to 1.5 ms−.

ABOUT THE REASONS FOR THE CHANGE IN THE MECHANICAL PROPERTIES OF PAPER ASHLESS FILTERS DURING THEIR PROCESSING IN A UNIPOLAR CORONA DISCHARGE

The article presents the study results of the structure and properties of paper ashless filters "Blue tape". It is shown that the "Blue tape" filter paper has a fairly high density with a relatively small number and size of voids (pores) between the fibers. When processing filters in the corona discharge field, an increase in their mechanical properties by 3.5–6% is observed, this is mainly due to the strengthening of the interfiber bond forces. The implementation of increased electrostatic bonding forces in the sheet structure leads to an increase in the resistance to the external tensile force necessary to break the paper filter. The observed dependences are associated with the orientation and ordering of the pulp and paper material structural elements, with an increase in the potential of the double electric layer on the fibers surface under the charge action carriers injected into the paper volume from the corona discharge and with the formation of a hetero charge due to the orientation of the polar cellulose groups and macromolecule segments during electreting. This is confirmed by the increase in the ζ – potential of the fibers of filters during processing in a negative corona discharge - it was found that the zeta – potential value of electret ashless filters is 18% higher than for the initial ones. The achieved results of increasing the ashless filters physico- mechanical properties will increase the efficiency of their use.

Separation of oil emulsion using polyacrylonitrile membranes, modified by corona discharge

It is investigated the influence of the parameters of the unipolar corona discharge (the treatment time, voltage) on the performance and selectivity of separation of model emulsions “oil in water” based on the oil in the Devonian deposits Tomatocage field (Republic of Tatarstan) using polyacrylonitrile membranes with a molecular weight cut-off of 60 kDa particles. Determined COD values of the original emulsions and filtrates. The values of the processing time (30 seconds) and voltage of the corona (5 kV) membranes, which achieved the best performance and selectivity of the separation process of oil-water emulsion. Sitting drop methods, x-ray diffraction and atomic force microscopy showed changes of the surface structure and internal structure of treated membrane. In particular, there was decrease in the wetting angle from 45.1 to 43.3 and an increase in the degree of crystallinity from 0.15 to 0.18, which is due to the flow on the surface of PES membrane processes of etching and oxidation resulting from exposure to a unipolar corona discharge ozone, which is also confirmed by images of the surface of the filter elements and the histograms of the topography, based on which it showed a decrease in height and number of protrusions from 42 nm and 7500 to 10 nm and 2500.