ETHYL CORP <EY> UNITS COMPLETE ACQUISITON Ethyl Corp said its subsidiaries completed the acquisiton of Nelson Research and Development Co <NELR>. The merger was approved following completion on Jan 27 of a tender offer valued at approximately 55 mln dlrs, the company said. It added that Nelson, based in Irvine, Calif., will be operated as a wholly-owned subsidiary of Ethyl. Nelson designs and develops new drugs, Ethyl said.