Abstract: A play apparatus has a pair of devices. Each device has: a capture arrangement such as a cavity to capture an object such as a ball; an object detector to detect that the object has been captured; a transmission module to transmit a release signal; a receiver module to receive a release signal; and a release actuator to release the captured object. A first device detects capture of a first object, transmits a first release signal to cause a second device to release a second object. The first device withholds the first object until releasing it responsive to receipt of a second release signal indicating that another object has been captured by the second device.

Abstract: A play apparatus has a pair of devices. Each device has: a capture arrangement such as a cavity to capture an object such as a ball; an object detector to detect that the object has been captured; a transmission module to transmit a release signal; a receiver module to receive a release signal; and a release actuator to release the captured object. A first device detects capture of a first object, transmits a first release signal to cause a second device to release a second object. The first device withholds the first object until releasing it responsive to receipt of a second release signal indicating that another object has been captured by the second device.

Abstract: A treatment system comprises a reactor vessel (2) wherein an aqueous solution is chemically treated using titanium dioxide catalytic particles in the solution, a membrane device (18) including tubular filtering membranes in communication with the vessel 2 for separating the particles from the solution by detaining the particles on entry-surfaces of the membranes, and a sparging device which causes injected air to flow over the entry surfaces to discourage clogging of the membranes by the particles. The reactor vessel (2) contains UV tubes (3) and the membrane device includes a coarse bubble aeration delivery device for producing slug pattern flow of the air over the entry surfaces of the membranes.