Tannins and human health: a review. Chung KT, Wong TY, Wei CI, Huang YW, Lin Y. Department of Microbiology and Molecular Cell Sciences, University of Memphis, TN 38152, USA. Tannins (commonly referred to as tannic acid) are water-soluble polyphenols that are present in many plant foods.
How to Cast Jewelry. Jewelry casting is a process of making jewelry pieces that involves the pouring of liquid metal alloy into a mold. It is usually referred to as lost-wax casting because the casting mold is created using a wax model that is melted away to leave a hollow chamber in the middle of the mold.
Architectural structures built with copper (usually roofing elements) corrode to give green verdigris (or patina). Decorative art prominently features copper, both in the elemental metal and in compounds as pigments. Copper compounds are also used as bacteriostatic agents, fungicides, and wood preservatives.