What’s old is new again As we prepare for CE's centennial celebration in the August issue, we've been reviewing the technological milestones that have defined the field of chemical engineering over the past 100 years. Along the way, we've been surprised to discover how often certain "modern" challenges resistance to metrication, the ongoing need for training, the need for pollution management, and consideration of alcohol as a fuel additive-were being hotly debated decades and decades ago.