The entrainment unit was modified slightly to improve the previously developed technique for measuring the solids entrainment rate. Several tests were conducted with -40 400 mesh Ottawa sand at system pressures of 50, 150, 300 and 450 psig and at various fluidization velocities to determine the effects of pressure and bed fluidizing-gas velocity on the entrainment rate. The initial entrainment rate (E/sub i/) was found to be proportional to the 2.11, 4.33, 5.67, and 8.44 powers of the gas velocity at the four operating pressures. The results were also analyzed to estimate the effects of pressure and gas velocity on the specific entrainment rate (E/sub s/) of particles that were 49, 58, 69, and 83 microns in diameter. The E/sub s/ for each particle size increased significantly with system pressure and gas velocity. The entrainment rate was found to increase much more rapidly with increasing gas velocity at higher pressures than at lower pressures. Tests were conducted to determine the effects of temperature, gas velocity, and oxygen concentration on the tendency of coal chars to sinter in fluidized beds. Tests were also conducted to determine the effect additional fluidizing gas in the ring below the distributor nozzles had on the sintering tendency of coal chars. At 1600/sup 0/F, the distributor nozzles were clean; at 1650/sup 0/F, the nozzles were coated with a layer of ash. The sinters formed at 1775/sup 0/F were slightly larger and heavier than those formed at 1825/sup 0/F. It was observed that the quantity of sinters decreased with a decreasing oxygen input rate. At 1650/sup 0/F, the addition of fluidizing gas in the ring below the distributor nozzle did not have any apparent effect on char sintering. Certain other results are also described. (LTN)