The sparging of the gas bubbles is {HEAD ~ the main mechanism} for {TAIL ~ mixing}, catalyst suspension, and dispersion 
for
The sparging of the gas bubbles is { HEAD ~ the main mechanism } for { TAIL ~ mixing } , catalyst suspension , and dispersion
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH