Search

Detailed characterization of a microwave cavity discharge in the supersonic flow of Ar/H2/Air mixtures at static pressures of 1–10 Torr and Mach number 2 is mostly based on emission spectroscopy techniques. In the conditions close to real combustion environments, effects of hydrogen and air admixture to plasma parameters and population of excited species in the discharge are demonstrated. The effects resulting in ionization loss are discussed from the aspects of dominant mechanisms and consequences for the plasma assisted hydrogen oxidation. [ABSTRACT FROM AUTHOR]

The air plasma effluent of an arc-seed microwave torch is used to kill bacterial spores contained inside an envelope. The torch is operated at a 60-Hz periodic mode (with about 40% duty cycle) and runs stably at a low airflow rate (e.g., 0.3931/s). The images of plasma torch plumes show that the arc loop of the discharge prolongs from the electrodes by nearly 3 cm and microwave energizes the charge particles along the arc loop considerably. The emission spectroscopy of the torch indicates that the plasma effluent contains an abundance of reactive atomic oxygen. Bacillus cereus is chosen for the biological agent in the decontamination experiment. The experiment and the decontamination efficacy of this torch are presented. The averaged temperature inside the envelope is measured to be less than 40 °C, thus ruling out the thermal decontamination mechanism. [ABSTRACT FROM AUTHOR]