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The present paper is focused on investigation of the electrical, hydrodynamic and acoustic parameters of underwater plasma discharges, stabilized with thin copper wires. The experimental current and acoustic waveforms have been obtained using different combinations of the circuit capacitance, charging voltage and wire length. The resistances of plasma discharges have been calculated for all combinations of electrical and topological parameters, based on the constant resistance approach. Phenomenological scaling relationships that link the plasma resistance and the total energy delivered to the plasma, the period of discharge cavity oscillation and the peak magnitude of the acoustic impulse have been obtained. These relationships can be used in optimization of the acoustic output from the wire-guided discharges for different practical applications.

Pulsed electric field (PEF) treatment can be used to facilitate microbial cell lysis. The aim of this paper is to investigate this effect of PEF treatment on microalgae. The PEF system used in this paper consists of a pulse generator and treatment cell with parallel-plane metallic electrodes. The PEF treatment of microalgae, Spirulina, was conducted using 33.3- and 66.7-kV/cm electric field impulses. The efficiency of the PEF treatment for inactivation of microalgae was assessed by comparison of the growth curves of PEF-treated and untreated samples. Results showed that growth of microalgae can be stopped by the application between 100 and 500 high-field impulses with field magnitude 33.3 kV/cm. When the field is increased to a magnitude of 66.7 kV/cm, the growth of microalgae can be stopped by application of 50 impulses. Overall, this paper confirms that PEF treatments can be used for the inactivation of algae and the energy consumption of the PEF process can be reduced using suspensions with lower electrical conductivity.