42 RESEARCH AND DESIGN SERVICES, NAMELY, RESEARCH AND DESIGN SERVICES OF APPARATUS, NAMELY, COLLECTION PIPES, SCRUBBERS, CONDENSERS, COLLECTION TANKS, DROPLET SEPARATORS, FANS, STEAM EJECTORS, RUPTURE DISCS AND FLAME ARRESTERS, AND INCINERATORS RELATED TO CIRCULATION OF CHEMICALS IN PULP MILLS; RESEARCH AND DESIGN SERVICES OF APPARATUS, NAMELY, COLLECTION PIPES, SCRUBBERS, CONDENSERS, COLLECTION TANKS, DROPLET SEPARATORS, FANS, STEAM EJECTORS, RUPTURE DISCS AND FLAME ARRESTERS, AND INCINERATORS RELATED TO ENERGY PRODUCTION AND AIR POLLUTION CONTROL