Fish scale the surface, interacting only with the riblet tips, not causing any high-veloctiy flow in the valleys. Since this high velocity flow now only interacts with the riblet-tip, which is a very small surface area, the momentum transfer which causes drag is now much lower than before, thereby effectively reducing drag. Also, this reduces the cross-stream velocity fluctuations, which aids in momentum transfer too. The rough, sandpaper-like texture of shark and ray skin, coupled with its toughness, has led it to be valued as a source of rawhide leather, called shagreen. One of the many historical applications of shark shagreen was
Leather jacket are the hides most commonly used to make leather jackets. As soon as the skin is removed from the animal at the meat processing plant, it is refrigerated, salted, or packed in barrels of brine. It is then sent to the tannery where the skins undergo a series of processes designed to preserve and soften the hides. Sewing materials such as thread, lining, seam tape, buttons, snaps and zippers are generally bought from outside vendors and stored in the garment factory. In the later-half of the 20th century, the leather jacket—in many forms—achieved iconic status and general acceptance through an