The present invention discloses a process for producing a membrane for separating methane or carbon dioxide, having excellent heat resistance, durability and anti-chemical agent resistance. A digital cymbal displacement detection unit in accordance with the present disclosure is configured to be directly mounted on the tube above the stand of an electronic hi-hat, as with any conventional hi-hat, without any need of changing the way how the electronic hi-hat is operated. For larger ponds, several of the interlocking sections are fitted into one another, thereby providing a fish habitat of larger overall dimensions. Next, an initial film of the metal is deposited into the micro-recessed structure using at least a first electroplating waveform having a first current density. The apparatus may be provided as a light weight wrist wearable instrument. This imager enables easy computation of pixel intensity histograms.