{TAIL ~ The packed tower} includes a packing arrangement including a lower bed of mobile packing elements, and {HEAD ~ an adjacent upper bed} of fixed packing elements 
{ TAIL ~ The packed tower } includes a packing arrangement including a lower bed of mobile packing elements , and { HEAD ~ an adjacent upper bed } of fixed packing elements
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH