Coal assay heating value is based on the moisture content as mined, but without any free water. The ISO has a coal ranking system that also ranks coals; the sub-divisions do not align with the ASTM standard. "Coal Analytical Methods" Blackwell Scientific Press, 1984. Coal assay Coal analysis techniques are specific analytical methods designed to measure the particular physical and chemical properties of coals. These methods are used primarily to determine the suitability of coal for coking, power generation or for iron ore smelting in the manufacture of steel. Coal comes in four main types or ranks: lignite or brown coal, bituminous
What If?: Serious Scientific Answers to Absurd Hypothetical Questions the Month". The book was a Goodreads Choice Awards "Best Nonfiction" nominee in 2014 as well. What If?: Serious Scientific Answers to Absurd Hypothetical Questions What If?: Serious Scientific Answers to Absurd Hypothetical Questions is a non-fiction book by Randall Munroe in which the author answers hypothetical science questions sent to him by readers of his webcomic, "xkcd". The book contains a selection of questions and answers originally published on his blog "What If?", along with several new ones. The book is divided into several dozen chapters, most of which are devoted to answering a unique question. "What If?" was