Production of theJoshi-Effect in air under silent electric discharge

Summary

The production and potential variation of theJoshi-Effect in air under silent electric discharge have been studied at eleven pressures in the range 28–258 mm. The applied potential was varied in the range 0·47 to 2·93 kV by steps. Both the positive and negativeJoshi-Effect of large magnitude, as high as 400% and 100% respectively in the case of the “blank” ozonizer and 675% and 100% respectively when the ozonizer was given a film of HgCl₂ on its inner annular wall, have been observed. In the pressure range studied, theJoshi-Effect expressed both as −Δi and −%Δi decreases numerically as the pressure increases; −%Δi is found to be maximum near V _m . Annular films of KCl, BaCl₂, HgCl₂ and NaOH enhance theJoshi-Effect in the order KCl>BaCl₂>HgCl₂>NaOH.

The rapid decline in the value of the positiveJoshi-Effect, obtained at applied potentials less than V _m of the system, to zero at/near V _m and its change-over to the negativeEffect is remarkable. The very pronounced values of theJoshi-Effect, both positive and negative, obtained in the present work is attributed to the large surface area due to the special ozonizer size and the selectivity of the copper oxide rectifier towards the high frequency components of the discharge current.

A concept of “corresponding potentials” on the basis of which comparison of the chemical and physical-chemical properties of gases under electrical activation may be made, has been advanced. It is suggested that gases subjected to their respective V _m or some “reduced” potential$V_r = \frac{{V - V_m }}{{V_m }}$, where V is the actual applied potential will be in “corresponding states” and comparison of their properties under such electrical stress should yield significant results. It has been found possible to explain,inter alia, the production near V _m of maximumJoshi-Effect calculated as −%Δi making use of the above concept.