Scott Zhang’s 28-year career at Honeywell hinged on an urgent, radical decision. It was 1990, and Zhang had just wrapped up his master’s degree in mechanical engineering at Illinois Tech. He had completed a three-month internship at Honeywell subsidiary Universal Oil Products in Des Plaines, Illinois, and loved it, but there was a serious problem: In order to pursue a career at UOP, he would need to drop mechanical engineering, the discipline to which he had just devoted six years of study, and instead become a chemical engineer. No problem, Zhang figured. He left the doctoral program he’d enrolled in and earned his Ph.D. in chemical engineering, while also working part-time at UOP. He has never looked back.