Editing Chemical engineering (section)

===New concepts and innovations===
[[File:Fuel cell NASA p48600ac.jpg|thumb|Demonstration model of a direct-methanol [[fuel cell]]. The actual fuel cell stack is the layered cube shape in the center of the image.]]

In the 1940s, it became clear that unit operations alone were insufficient in developing [[chemical reactor]]s. While the predominance of unit operations in chemical engineering courses in Britain and the United States continued until the 1960s, [[Transport phenomena (engineering & physics)|transport phenomena]] started to receive greater focus.{{sfn|Cohen|1996|p=185}} Along with other novel concepts, such as [[process systems engineering]] (PSE), a "second paradigm" was defined.{{sfn|Ogawa|2007|p=2}}{{sfn|Perkins|2003|p=29}} Transport phenomena gave an [[systems analysis|analytical]] approach to chemical engineering{{sfn|Perkins|2003|p=30}} while PSE focused on its synthetic elements, such as those of a [[control system]] and [[Process design (chemical engineering)|process design]].{{sfn|Perkins|2003|p=31}} Developments in chemical engineering before and after World War II were mainly incited by the [[petrochemical industry]];{{sfn|Reynolds|2001|p=177}} however, advances in other fields were made as well. Advancements in [[biochemical engineering]] in the 1940s, for example, found application in the [[pharmaceutical industry]], and allowed for the [[mass production]] of various [[antibiotic]]s, including [[penicillin]] and [[streptomycin]].{{sfn|Perkins|2003|pp=32–33}} Meanwhile, progress in [[polymer science]] in the 1950s paved way for the "age of plastics".{{sfn|Kim|2002|p=7S}}