Abstract: An apparatus for cleaning a surface, the apparatus including a body defining a chamber, an inlet for liquid flow into the chamber, an outlet for liquid flow from the chamber, a nozzle connected to the outlet for generating an output flow of liquid for cleaning a surface, an acoustic transducer associated with the body to introduce acoustic energy into the liquid within the chamber whereby the acoustic energy is present in the liquid flowing out of the nozzle, and a gas bubble generator for generating gas bubbles within the liquid flowing out of the nozzle.

Abstract: An apparatus for cleaning a surface, the apparatus including a body defining a chamber, an inlet for liquid flow into the chamber, an outlet for liquid flow from the chamber, a nozzle connected to the outlet for generating an output flow of liquid for cleaning a surface, an acoustic transducer associated with the body to introduce acoustic energy into the liquid within the chamber whereby the acoustic energy is present in the liquid flowing out of the nozzle, and a gas bubble generator for generating gas bubbles within the liquid flowing out of the nozzle.

Abstract: An apparatus for cleaning a surface includes a body defining a cavity and terminating in a distal end that is adapted, in use, to be in the vicinity of a surface to be cleaned such that the surface forms an end wall of a chamber including the cavity; at least one cleaning liquid inlet for flow of a cleaning liquid into the chamber; a divider located in or at the end of the cavity that divides the chamber into first and second portions, the second portion, in use, being in fluid communication with the surface to be cleaned; and an acoustic transducer associated with the first portion to introduce acoustic energy into the chamber; wherein the divider is adapted to permit the passage of acoustic energy therethrough from the first portion to the second portion of the chamber to thereby allow pressure fluctuations to be generated at the surface.

Abstract: An apparatus and method for prevention and treatment of marine biofouling on a surface to be treated by the apparatus includes a body defining a cavity, the body terminating in a distal open end that is adapted, in use, to be in the vicinity of a surface to be treated such that the surface forms a first end wall of a chamber within the cavity; an acoustic transducer mounted within the cavity to form an opposite second end wall of the chamber, the acoustic transducer being adapted to cause acoustic pressure fluctuations; and a reservoir for a liquid, the reservoir including an inlet passage and a plurality of mutually spaced outlet passages for liquid flow from the reservoir into the chamber, the outlet passages at least partially surrounding the chamber in the vicinity of the distal open end.

Abstract: An apparatus for cleaning a surface includes a body defining a cavity and terminating in a distal end that is adapted, in use, to be in the vicinity of a surface to be cleaned such that the surface forms an end wall of a chamber including the cavity; at least one cleaning liquid inlet for flow of a cleaning liquid into the chamber; a divider located in or at the end of the cavity that divides the chamber into first and second portions, the second portion, in use, being in fluid communication with the surface to be cleaned; and an acoustic transducer associated with the first portion to introduce acoustic energy into the chamber; wherein the divider is adapted to permit the passage of acoustic energy therethrough from the first portion to the second portion of the chamber to thereby allow pressure fluctuations to be generated at the surface.

Abstract: An apparatus and method for cleaning a surface, the apparatus comprising: a body defining a cavity, the body terminating in a distal end that is adapted, in use, to be in the vicinity of a surface to be cleaned such that the surface to be cleaned forms an end wall of a chamber including the cavity; at least one cleaning liquid inlet for flow of a cleaning liquid into the chamber; a divider located in or at the end of the cavity that divides the chamber into a first portion and a second portion, the second portion, in use, being in fluid communication with the surface to be cleaned; and an acoustic transducer associated with the first portion of the chamber to introduce acoustic energy into the chamber; wherein the divider is adapted to permit the passage of acoustic energy therethrough from the first portion of the chamber to the second portion of the chamber to thereby allow pressure fluctuations to be generated at the surface to be cleaned.

Abstract: An apparatus and method for cleaning a surface, the apparatus comprising: a body defining a cavity, the body terminating in a distal end that is adapted, in use, to be in the vicinity of a surface to be cleaned such that the surface to be cleaned forms an end wall of a chamber including the cavity; at least one cleaning liquid inlet for flow of a cleaning liquid into the chamber; a divider located in or at the end of the cavity that divides the chamber into a first portion and a second portion, the second portion, in use, being in fluid communication with the surface to be cleaned; and an acoustic transducer associated with the first portion of the chamber to introduce acoustic energy into the chamber; wherein the divider is adapted to permit the passage of acoustic energy therethrough from the first portion of the chamber to the second portion of the chamber to thereby allow pressure fluctuations to be generated at the surface to be cleaned.

Abstract: An apparatus for cleaning a surface, the apparatus including a body defining a chamber, an inlet for liquid flow into the chamber, an outlet for liquid flow from the chamber, a nozzle connected to the outlet for generating an output flow of liquid for cleaning a surface, an acoustic transducer associated with the body to introduce acoustic energy into the liquid within the chamber whereby the acoustic energy is present in the liquid flowing out of the nozzle, and a gas bubble generator for generating gas bubbles within the liquid flowing out of the nozzle.

Abstract: A method for indicating the concentration of a substance in solution includes passing an alternating voltage between a first electrode structure having coated thereon a polymer and a second separate counter electrode in the solution. The polymer is in one of an oxidized and a reduced state, between which states its conductivity varies. Changes in the conductivity of the polymer coating are measured, the measurement being representative of the state of the polymer and thereby of the concentration of the substance in the solution. Electrodes for use in this method are also described.