Gas mixing enhanced by power modulations in atmospheric pressure microwave plasma jet

Microwave plasma jet operating in atmospheric pressure argon was power modulated by audio frequency sine envelope in the 10^2 W power range. Its effluent was imaged using interference filters and ICCD camera for several different phases of the modulating signal. The combination of this fast imaging with spatially resolved optical emission spectroscopy provides useful insights into the plasmachemical processes involved. Phase-resolved schlieren photography was performed to visualize the gas dynamics. The results show that for higher modulation frequencies the plasma chemistry is strongly influenced by formation of transient flow perturbation resembling a vortex during each period. The perturbation formation and speed are strongly influenced by the frequency and power variations while they depend only weakly on the working gas flow rate. From application point of view, the perturbation presence significantly broadened lateral distribution of active species, effectively increasing cross-sectional area suitable for applications

Simple method for measurement of feltability of rabbit hair

458-462In this work, a simple method for testing the felting propensity of carded top prepared from chemically treated, short and thick animal hairs, together with the necessary devices has been developed. Similar to the Aachen felting test, external force is applied to the wet sample of the fibres until felting occurs. The felting propensity is then determined from the dimensions of the resulting felted body. The main difference is that the sample is prevented from disintegration during the procedure that usually occurs, when a standard Aachen test is applied