However, there is no consensus among volcanologists on how to define an active volcano. As of 2012, PHIVOLCS lists 23 volcanoes as active in the Philippines, 21 of which have historical eruptions; one, Cabalian, which is strongly fumarolic volcano [further explanation needed]; and one, Leonard Kniaseff, which was active 1,800 years ago (C14).
Polyvinyl Chloride PVC. Polyvinyl Chloride (PVC) is a major plastics material which finds widespread use in building, transport, packaging, electrical/electronic and healthcare applications.
PVC stands for Polyvinyl Chloride. What is interesting is that the Chloride makes up more than half the finished weight of PVC which is what makes the final window resistant to fire.The modern starting materials for the manufacture of PVC are oil and salt. Both of these are products of nature.hat is interesting is that the Chloride makes up more than half the finished weight of PVC which is what makes the final window resistant to fire. The modern starting materials for the manufacture of PVC are oil and salt. Both of these are products of nature.