Unusual types of gramophone records Hi-Fi was a system of proprietary records and players designed for use in automobiles, utilizing a slower play speed and high stylus pressure. With their origin stretching back to the dawn of recorded sound at the turn of the 20th century, flexible recording media have been made from a variety of materials including foil, paper, and–in the 1950s–thin flexible vinyl known as flexi discs. Thin, flexible paper-based records were briefly popularized in the 1930s by Hit of the Week Records and Durium Records. "Melody Cards" were popular in the late 1950s. They took the form of an oversized rectangular postcard
Aluminum polymer composite Aluminum polymer composite An aluminum polymer composite (APC) material combines aluminum with a polymer to create materials with interesting characteristics. In 2014 researchers used a 3d laser printer to produce a polymer matrix. When coated with a 50-100 nanometer layer of aluminum oxide, the material was able to withstand loads of as much as 280 megapascals, stronger than any other known material whose density was less than , that of water. Spherical aluminum foam pieces bonded by polymers produced foams that were 80-95% metal. Such foams were test=manufactured on an automated assembly line and are under consideration as automobile parts.