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