Nearly all the major equipment manufacturers—including Caterpillar, Case/New Holland/Kobelco, Komatsu, Deere, Volvo, Terex and engine specialist Cummins—plan to use a combination of exhaust-gas recirculation (EGR) and a diesel particulate filter (DPF), to meet Interim Tier 4. Image: CNH EGR + DPF Photo: CNH SCR Photo: JCB Related Links: Next Round of Federal Regulations Has Suppliers Retooling Clean Diesel The Future of Clean Diesel Is … Gasoline? The other major technology for Interim Tier 4 is selective-catalytic reduction (SCR), which converts nitrogen oxides to harmless nitrogen and water by dosing exhaust fumes with small amounts of diesel exhaust fluid, an aqueous
Arch dams, classically curved monoliths situated in narrow valleys, are not as common as other types of dams, such as embankment dams and gravity dams. ENR takes a look at some of the biggest arch dams in the world, both completed and under construction.