Penulis: Gary P. Keeler

Ruthenium is exceedingly rare, as it is only the 74th most abundant metal on Earth. The element is generally found in ores with the other platinum group metals in the Ural Mountains and in North and …

Waste management is the collection, transport, processing, recycling or disposal, and monitoring of waste materials. The term usually relates to materials produced by human activity, and is generally …