It is with sadness to let you all  know that Dr. Fred A. Zenz has passed away last Wednesday morning.  As our founding father, Fred started PSRI in 1970 and continued with PSRI until 1989.  He is known as one of the leaders in fluidization and the scale-up of fluidized and circulation fluidized beds.  Many of us have his famous book, entitled “Fluidization and Fluid-particle Systems,” on our bookshelf.  His book resulted in him being named as “30 Authors of Groundbreaking Chemical Engineering Book.”  He was also listed as the  “100 Chemical Engineers of the Modern Era.” Many of the correlations, equations, and concepts we use today are based on Fred’s research including cyclone collection efficiency, entrainment and jet penetration lengths.  He has spent his life contributing to the science and he will be missed.  More about his remarkable life can be found at