For both the fast and turbulent fluidized beds, local measurements were taken at 11 radial positions and 5 heights along the riser for each particle system and operating condition. The riser phenomena assessed here include cluster (namely, local appearance probability, duration, and frequency) ^16,17,20, mass flux (both local flux and overall flux across the cross-section) ^15,21 and segregation ^14,21. The same instruments fabricated by PSRI were used for characterization. Specifically, the local clusters were measured using fiber optic probes, which housed two fibers that converged at the probe tip, while the local mass fluxes were measured using extraction probes with an inner diameter of 0.017 m and the probe tip oriented 90° to the probe shaft to capture upward or downward flow. The samples collected from the extraction probes were sieved to obtain segregation data.