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No it means protrusions sticking out of a cross-hatched screen:
http://www.google.com/patents/US20110073542

"ALGAL TURF SCRUBBER (ATS) FLOWAYS ON THE GREAT WICOMICO RIVER, CHESAPEAKE BAY: PRODUCTIVITY, ALGAL COMMUNITY STRUCTURE, SUBSTRATE AND CHEMISTRY" -- Walter H. Adey, John B. Miller, Lee-Ann C. Hayek,...