Photo by Tudor Van Hampton Navistar's switch to SCR will impact supply deals, such as the truck it makes for Caterpillar. Related Links: Navistar Goes It Alone In 2011 Navistar Submits 13-Liter Engine for EPA Certification Navistar International Corp. is abandoning its decade-long Class 8 diesel-truck-engine strategy and turning to rival and onetime supplier Cummins Inc. for a viable solution. The move marks a setback for the Lisle, Ill.-based Navistar, which had been bullish about exhaust-gas-recirculation, or EGR, its in-cylinder technology worth about $700 million in development costs since 2001. The truck engines still do not meet Environmental Protection Agency
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.