Currents may also be generated by density differences in water masses caused by temperature and salinity variations. These currents move water masses through the deep oceanâtaking nutrients, oxygen, and heat with them. Occasional events also trigger serious currents. Huge storms move water masses.
Ray-ban and most other manufacturers frames are made from Plastic compounds. Ray-ban used to make all its glasses out of 'glass'. Now it makes its sunglass products out of scratch resistent plastics. Often they will 'feel' like glass but are in fact most usually plastic production.
Hard contact lenses are often made of PMMA. As an injectable filler, PMMA is formulated into microscopic spheres that are suspended in a carrier of collagen with a small amount of the anesthetic lidocaine. It is used to permanently raise indented scars and fill in folds like the nasolabial folds.