37 Maintenance, repair, improvement, construction and installation of machines and equipment for mining, energy production and for treatment of industrial waste processing streams, and not for land vehicles, namely, steam engine boilers, waste heat boilers, heat recovery steam-operated generators, acid generation machines, electroplating machines, electric pumps, pumps for machines, electrochloration machines, power-operated sludge cleaning machines for steam generators; maintenance, repair, improvement, construction and installation of machines and equipment for the treatment, processing and galvanizing of metal, namely, stainless steel, high tensile steel and aluminum, namely, rolling mills, metal coating machines, skin pass mills, metalworking machines, continuous steel processing lines, fast quenching and cooling lines for steel; maintenance, repair, improvement, construction and installation of machines and equipment for steam generation, power generation, treatment of industrial waste streams and other industrial processes, namely, solar boilers, energy generation power plants, water desalination units, and water filtration units; maintenance, repair, improvement, construction and installation of machines and equipment for the treatment, processing and galvanizing of metal, including stainless steel, high tensile steel and aluminum, namely, reheating and heating treatment furnaces, annealing furnaces; maintenance, repair, improvement, construction and installation of machines and equipment, namely, diesel engines for land vehicles, armored vehicles, locomotives, guns, ballistic and guided missiles, targeting systems which acquire targets for guns and ballistic or guided missiles for armored turrets and cupolas and armored platforms, namely, unmanned aerial vehicles (UAVs)