Engineer Wayne Coste: Propelled Demolition in the Mechanics of the Twin Towers Destruction

What is Propelled Demolition? and how might it differ from traditional Controlled Demolition? Can a consistent hypothesis be created that knits together the evidence presented by my previous guests on RichardGage911Unleashed? What structural weaknesses in the design of the Twin Towers may have been exploited, resulting in the outward ejection of almost all of the buildings components?