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

Tetrakis(trimethylsilyloxy)silane for nanostructured SiO2-like films deposited by PECVD at atmospheric pressure

We performed the thin films deposition using atmospheric pressure plasma enhanced chemical vapour deposition (AP-PECVD) by means of a radiofrequency and a microwave plasma jets operating with mixtures of argon and tetrakis(trimethylsilyloxy)silane (TTMS)

Laboratory investigations applied to wood dust emmited by electrical hand-held belt sander

Aim of this paper was to investigate the effects of grit size and wood species on mass concentration and size distribution of wood dust produced by hand-held belt sander. Experimental study was designed as 2x2 full factorial experiments. Experimental parameters and their levels were abrasive grain size (P80, P120) and wood species (European beech (Fagus sylvatica L.), Norway spruce (Picea abies)).The mass concentration of emitted wood dust was measured using aerosol monitor (TSI Inc., DustTrak DRX 8533). Sampler head was sited in place representing breathing zone of operator of sander. The results was analysed employing the analysis of variance (ANOVA) with 5% of significance level. Real-time measurements demonstrated that spruce wood generated higher dust concentrations than beech wood due to difference in abrasion durability. Compared to sanding belt with P80 grit size, approximately 16%-32% higher dust concentration was generated when the sanding belt with P120 grit size was used