text: In 1964 he joined the United Kingdom Atomic Energy Authority.  In 1966 he obtained a research assistant post at the Nottingham and District Technical College where he began his research on particle technology.  In 1969 he moved to the chemical engineering department of Loughborough University of Technology.
  He stayed there until 1983 when he moved to Delft University of Technology as a full professor, of chemical technology in the Departments of chemical engineering, mechanical engineering and mining.  In 2000 he moved to the University of Florida as full professor in the National Science Foundation Engineering Research Centre, in particle science and technology, forming the largest academic group in powder mechanics in the US.  He continued there until his death.