Membrane

A membrane is a selective barrier; it allows some things to pass through but stops others. Such things may be molecules, ions, or other small particles. Biological membranes include cell membranes (outer coverings of cells or organelles that allow passage of certain constituents);nuclear membranes, which cover a cell nucleus; and tissue membranes, such as mucosae and serosae. Synthetic membranes are made by humans for use in laboratories and industry (such as chemical plants). The influent of an artificial membrane is known as the feed-stream, the liquid that passes through the membrane is known as the permeate, and the liquid containing the retained constituents is the retentate or concentrate.

These concept of a membrane has been known since the eighteenth century, but was used little outside of the laboratory until the end of World War II. Drinking water supplies in Europe had been compromised by the war and membrane filters were used to test for water safety. However, due to the lack of reliability, slow operation, reduced selectivity and elevated costs, membranes were not widely exploited. The first use of membranes on a large scale was with micro-filtration and ultra-filtration technologies. Since the 1980s, these separation processes, along with electrodialysis, are employed in large plants and, today, a number of experienced companies serve the market.

The Membranes

The Membranes are a post-punk band formed in Blackpool, Lancashire in 1977, the initial line-up being John Robb (bass guitar), Mark Tilton (guitar), Martyn Critchley (vocals) and Martin Kelly (drums). Critchley soon left, with Robb and Tilton taking on vocals, and Kelly moving to keyboards, with "Coofy Sid" (Coulthart) taking over on drums. Their first release was the "Flexible Membrane" flexi-disc in 1980, and over the next 11 years they would go on to release six studio albums. Their first single proper, "Muscles", was a single of the week in the UK music press and a big club hit in New York being played in the Danceteria by the likes of the Beastie Boys eventual DJ Mojo and other cutting edge New York DJs. Kelly left after "Muscles", to be replaced by Steve Farmery on guitar for the follow-up Pin Stripe Hype EP. The band pioneered the avant noise scene of Big Black and Sonic Youth for several years with their critically acclaimed "Spike Milligan's Tape Recorder" single and Death To Trad Rock EP and their debut Gift Of Life album. They were the first band to be signed to Alan McGee's Creation label but the deal fell though when McGee could not afford to pay their studio bill for the "Spike Milligan's Tape Recorder" single. The band relocated to Manchester in 1983, and "Spike Milligan's Tape Recorder" was issued on the Criminal Damage label, which met with a positive critical response but distribution problems limited its impact.