I've been a process engineer involved in the manufacture of solar cells. The whole industry more-or-less ate it and I found myself unemployed again in 2013, so now I'm about to move to Sweden to do some early stage R&D. I wasn't really able to transition into the semiconductor or optoelectronics industry here in the US the way that I had hoped I would.
Previously I designed bridges and building systems, and I nearly became an architect.