Volcano of classifying magmatic volcanoes is by their frequency of eruption, with those that erupt regularly called active, those that have erupted in historical times but are now quiet called dormant or inactive, and those that have not erupted in historical times called extinct. However, these popular classifications—extinct in particular—are practically meaningless to scientists. They use classifications which refer to a particular volcano's formative and eruptive processes and resulting shapes. There is no consensus among volcanologists on how to define an "active" volcano. The lifespan of a volcano can vary from months to several million years, making such a distinction sometimes
Mold control and prevention in libraries Mold control and prevention in libraries Mold prevention is a conservation activity that is performed in libraries to protects books and other materials from deterioration caused by mold growth. Mold prevention consists of different methods, such as chemical treatments, careful environmental control, and manual cleaning. Preservationists use one or a combination of these methods to combat mold spores in library collections. Due to its resilient nature, mold prevention has become an important activity among preservation librarians. Mold reproduces by releasing spores into the air. It becomes active after being in a dormant state and responds to fluctuating temperature, air flow,