Abstract: A method for electrochemical disinfection of an aqueous solution, the method comprising the steps of: providing one or more disinfecting cells for retaining an aqueous solution, each disinfecting cell including one or more electrode pairs positioned therein; arranging the one or more disinfecting cells along a flow path, the flow path including an inlet to and an outlet from the one or more disinfecting cells; determining at the one or more disinfecting cells the electrical conductivity, or specific conductance of the aqueous solution; determining from the electrical conductivity, or specific conductance of the aqueous solution a voltage to apply across the one or more electrode pairs at a current sufficient to produce disinfection species therein; and passing the current from the one or more electrode pairs to the aqueous solution to produce a modified aqueous solution.

Abstract: A directional micro-phone is disclosed which comprises a microphone array (3) having a plurality of microphone elements (4,5,12,13) of which the element (4) is a rear element and the other elements arc forward elements. A processor (19,31) is connected to the elements. The processor can be a hardware processor for processing signals or it can be a software controlled system for processing signals. The processor one of the forward elements (5,12,13) and thereafter establishes a window of opportunity for receipt of the wave at the rear element (4). The window of opportunity is set such that only waves emanating from a particular direction will arrive in that time frame, thereby enabling acoustic waves from that direction to the process by the microphone and other waves from different directions eliminated. The angle of arc of the microphone from which acoustic waves are received and processed can be set by changing the size of the window of opportunity t3-t2.