Special section in honour of Professor Norman Epstein of the University of British Columbia

Rare are the people who, upon a first meeting, etch an indelible mark upon your mind. Professor Normal Epstein was such a person. I had the privilege of first meeting him relatively late in my career, during one of the annual receptions of The Canadian Journal of Chemical Engineering (CJCE). As a former Editor-in-Chief of the CJCE (from January 1985 to December 1989), Prof. Epstein made it a point to attend the CJCE receptions during the yearly CSChE conferences all the way up into his nineties. I remember the pleasant conversations we had during these meetings, as well as the invaluable pieces of advice he gave me on how to manage the CJCE. (Talk about large shoes to fill!) He was also a regular reviewer of papers for our Journal. And what reviews they were: scientifically accurate, meticulous, respectful of the authors' ideas but not afraid of pointing out the weak points in their reasoning, and written in an elegant style that is now lost to most of us—in longhand! Prof. Epstein passed away on 29 July 2023—short of his 100th birthday—after a long and distinguished career in the Department of Chemical and Biological Engineering at the University of British Columbia. He was an outstanding chemical engineer, lecturer, mentor, and an inspiring leader in the areas of spouted beds, heat exchanger fouling, liquid–solid and three-phase fluidization, and dynamic particulate processes. Perhaps more importantly, he was a remarkable colleague, friend, and a true gentleman. It is, therefore, a great honour to write this preface introducing the special section of the CJCE dedicated to his many accomplishments. The 12 articles included herein cover many of the areas in which Prof. Epstein excelled and includes authors from across the globe, gathered together here to celebrate a life dedicated to chemical engineering science. ‘It is uniquely our choice as to how we look at the world, once we escape the formalisms of training and psychological inertia of our own consciousness. Looking at things from a new direction, interpreting the world in a different light is considered WISE, and accepting the perspectives of others is more precious than ever. Finding time and space for all in the discussion of science is the utmost priority, and our community of practice would benefit from change’. ‘We can consider how to fractionate the above teetering problem into subsystems, increasing complexity as we provide discrete connections in unit sub-shells, accommodating quantum and chaotic principles; however, we often lose sight of the larger microcosm of long-range interaction: Why we practice these technologies, and how we can work together for the better world that Norman dreamt of for nearly a century’. In a timely literature review, Jankovic and Wilkinson[10] explore the transition to electrochemical processes in clean energy technologies, with emphasis on hydrogen-containing fuels. Along similar lines, Bi et al.[11] discuss ammonium crossover as a function of membrane type and operating conditions in electrochemical flow cells for ammonia synthesis and water treatment applications. Finally, Qu et al.[12] close Prof. Epstein's special section with the relevant topic of biomass utilization, presenting a detailed kinetic study of microwave pyrolysis of sewage sludge and corn stalk mixture. I would like to thank all the authors who joined us in celebration of the remarkable career of our dear colleague and friend, Norman Epstein. Making mine the words of David R. Bruce, let's strive to ‘work together for the better world that Norman dreamt of for nearly a century’. I hope our readers will enjoy reading these articles as much as I did. João B. P. Soares: Conceptualization; writing – original draft. The peer review history for this article is available at https://www.webofscience.com/api/gateway/wos/peer-review/10.1002/cjce.25599.