Phonograph record a "De luxe" price. Later, Decca Records introduced vinyl Deccalite 78s, while other record companies used vinyl formulations trademarked as Metrolite, Merco Plastic, and Sav-o-flex, but these were mainly used to produce "unbreakable" children's records and special thin vinyl DJ pressings for shipment to radio stations. In the 1890s, the recording formats of the earliest (toy) discs were mainly 12.5 cm (nominally 5 inches) in diameter; by the mid-1890s, the discs were usually 7 inches (nominally 17.5 cm) in diameter. By 1910, the 10-inch (25.4 cm) record was by far the most popular standard, holding about of music or other
Quadratic mean diameter timber in a forest, because it has the practical advantage of being directly related to basal area, which in turn is directly related to volume. QMD can also be calculated as: formula_3 where BA is stand basal area, n is the number of trees, and k is a constant based on measurement units - for BA in ft and DBH in inches, k=0.005454; for BA in m and DBH in cm, k=0.0000785. Quadratic mean diameter In forestry, quadratic mean diameter or QMD is a measure of central tendency which is considered more appropriate than arithmetic mean for characterizing the group