Chuck Mueller, a member of Sandia National Laboratories technical staff, has received the 2008 Harry L. Horning Memorial Award for his work on the paper, "Early Direct-Injection, Low-Temperature Combustion of Diesel Fuel in an Optical Engine Utilizing a 15-Hole, Dual-Row, Narrow-Included-Angle Nozzle." Since Sandia's Combustion Research Facility (CRF) opened its doors in 1981, CRF researchers have captured the award seven times, which is more than any other institution. The Horning award annually recognizes the author(s) of the best paper relating to the better mutual adaptation of fuels and internal combustion engines presented at a meeting of the Society of Automotive Engineers (SAE) or any of its sections during any calendar year. The award preserves the memory of the dedication of SAE's 1925 president, Harry L. Horning, to the pursuit of improved mutual adaptability of engines and fuels. It serves as a motivation for others to follow in his footsteps. The award was established in 1938. Mueller coauthored the diesel combustion paper with colleagues from Caterpillar, the world's largest maker of construction and mining equipment, diesel and natural gas engines, and industrial gas turbines. The paper elucidates mechanisms by which liquid-fuel films can be formed within the combustion chamber and how the subsequent vaporization and/or ignition of the films can affect engine-out emissions.