Jim Hoffmann is a top US software engineer who has extensively analyzed the 3 World Trade Center (WTC) building demolitions (see Wikipedia: http://en.wikipedia.org/wiki/Jim_Hoffman ).
Jim Hoffmann, in a layperson-directed account of the finding by scientists Dr Niels Harrit and colleagues of unexploded nanothermite high explosive in all the World Trade Center dust samples analyzed (2009): “Backers of the official account of 9/11, including NIST officials, have dismissed evidence that aluminothermics were used to destroy the World Trade Center skyscrapers, claiming that thermite's slow reaction rate makes it an unsuitable tool for demolishing buildings. Despite repeated requests by scientists and researchers to address the potential role of advanced aluminothermic composites with high explosive power, officials have refused to acknowledge such materials… The implications of the discovery of unspent aluminothermic explosives and matching residues in World Trade Center dust are staggering. There is no conceivable reason for there to have been tons of high explosives in the Towers except to demolish them, and demolition is blatantly incompatible with the official 9/11 narrative that the skyscrapers collapsed as a result of the jetliner impacts and fires. The discovery of active thermitic materials adds to a vast body of evidence that the total destruction of the Towers were controlled demolitions, and to the subset of that evidence indicating the use of aluminothermic materials to implement those demolitions… As is obvious from a review of the literature on energetic materials, thermite-based pyrotechnics can be engineered to have explosive power similar to conventional high-explosives while providing greater energy density and much greater stability. Thus, aluminothermic cutter charges similar to the shaped charges used in commercial demolitions are entirely feasible.” .
. Jim Hoffmann, “Explosives Found in World Trade Center Dust. Scientists Discover Both Residues And Unignited Fragments Of Nano-Engineered Thermitic Pyrotechnics In Debris From the Twin Towers”, 9-11 Research, 9 December 2009: http://911research.wtc7.net/essays/thermite/explosive_residues.html .