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Three alcohols in water were compared in plasma production of the hydrogen-rich synthesis gas H₂ + CO. The 9 ns 9 kV negative pulses generated submerged discharges at very low average power of about 10 W, which was enough for the production of about 0.5 L/min synthesis gas containing up to about 65% H₂. The fastest production of the gas in all tested liquids required tuning of intense streamer discharges with the formation of small gas bubbles, including those with submicron diameters. The presence of submicron bubbles–nanobubbles was confirmed by high-resolution optical microscopy. Extraordinary properties of nanobubbles can explain the high production efficiency of the hydrogen-rich gas from mixtures of alcohol with water generated by the nanosecond pulsed plasma.

Submerged dc plasma generated by nanosecond pulses in ethanol and methanol mixtures with water confirmed efficient production of the hydrogen synthesis gas H₂ + CO. The comparison of ethanol and methanol was made for their 35% contents in water. The methanol electrolyte exhibited about 25% more efficient production of synthesis gas compared with ethanol. Tests with 9 ns 9 kV negative dc pulses at the average power of 10 W confirmed production of up to 0.5 l/min of the synthesis gas with over 65% content of H₂. In both electrolytes the experiments indicated important role of small gas bubbles in the process. The bubbles were evidently generated by very short streamers formed during the dc pulses. The extraordinary properties of small bubbles, particularly those with submicron sizes, could explain the efficient production of the hydrogen rich gas.

Spiral hollow cathodes represent interesting options for local PVD applications. Radio frequency powered smalldiameter spiral hollow cathodes made from 0.45 mm diameter Ta wire rolled around 0.5 mm diameter rod weretested in PVD regimes on silicon substrates at the gas pressure of 400 Pa (3 Torr). The PVD of Ta and reactivePVD of Ta-N resulted in deposition rates of about 130 nm/min with maximum thickness in the center of thecoating spots. However, part of the coating spots can be heavily eroded. At higher RF powers droplets from themelted Ta tip of the spiral can damage the coating and melt the Si substrate. The PVD rates of Ta in argon weresimilar as those for TaN. However, lower number of droplets of the melted Ta were formed in argon. The heatingof the spiral outlet and its effect on the coating was also more intense in nitrogen than in argon. The temperatureof the Si substrate table reached about 500 ◦C in 20 min in the nitrogen plasma and up to 400 ◦C in argon. Thisheating was higher on electrically grounded substrates than on the floating substrates. The effect of sharp outleton possible eroding of the sample was confirmed by a sharp ended 1 mm diameter stainless steel medical needleused as a hollow cathode.

Radio frequency Hollow Cathode based hybrid process integrating both Physical Vapor Deposition and Plasma Enhanced Chemical Vapor Deposition was used for deposition of amorphous carbon on glass samples. The films were subjected to high voltage pulses and the performance was compared with uncoated glass samples to test the protection ability of the films, the ability to prevent the deteriorating effects of corona flashovers/arcs. In contrast to the uncoated glass the well adherent carbon films with thicknesses between 3.5 and 17 mu m exhibited an excellent protection of the glass substrate against the flashovers/arc damages in both polarities of the electric field with voltages up to 300 kV.

Potential usage of the radio frequency (RF) spiral hollow electrodes in comparison with the compact hollow cathodes was examined for coating and other surface processing treatments. Most properties were found similar to the compact RF hollow cathodes. The non-conventional shapes of spiral hollow cathodes can be suitable for the inner coating in narrow tubes and pipes. Small diameter spiral cathodes can generate focused high-density ion flux capable of rapid etching of the substrate.

The hysteresis effect in the reactive process was investigated in the magnetron with a magnetized hollow cathode enhanced target (HoCET) in which the target is coupled with the hollow cathode magnetized by the magnetic field of the magnetron. The process, where both the magnetron and hollow cathode plasmas are combined, is compared to the magnetron sputtering. The hysteresis curve in the magnetized HoCET magnetron, recording the titanium emission intensity versus varying content of nitrogen in the gas mixture exhibits a local maximum on the increasing part of the curve. The hysteresis curve is shifted to lower contents of nitrogen than the hysteresis curve for the magnetron. It is concluded that more efficient utilization of the reactive gas takes place in this device.

Experimental examination of possibility to affect the shapes of flames under combustion of the liquified petroleum gas (LPG) were performed by several non-conventional cold atmospheric plasma arrangements. The lateral fused hollow cathode, the microwave surface wave plasma jet and the combination of these systems confirmed possibility of an efficient control of the flame shapes, increasing stability of flames and broadening of their front parts.

The atmospheric pressure plasma sources with a coaxial geometry were used for generation of the radio frequency, microwave and pulsed dc plasmas inside water and aqueous solutions. Pulsed dc plasma generated in ethanol-water mixtures leads to production of the hydrogen-rich synthesis gas with hydrogen content up to 65 % The effect of various plasma generation regimes on the performance of plasma, on the hydrogen production efficiency and on the hydrogen-rich synthesis gas production was examined. A role of the composition of the ethanol-water mixture was investigated.