fluid analysis services, namely analyzing used oil and other fluids to evaluate the mechanical condition of engines and equipment (namely engines for railroad locomotives, trucks, buses, automobiles, aircraft, boats, and other vehicles, and engines for off-road machinery and equipment such as that used in industrial plants and in the mining and construction industries) and the serviceability of oil and similar lubricants, which services are marketed to oil refineries, railroad companies, marine terminals, the military, truck and bus transportation companies, truck, bus, and automobile dealerships, leasing companies, and service centers, airports and aircraft service centers, industrial plants, mining companies, construction contractors, and the like