Particle Formation and Prevention in Compression Ignition Engines 
Efficient, compression-ignition engines dominate the heavy-duty transportation sector, but are significant sources of NOx and particulate matter. Dual-fuel natural gas engines ( reduce these emissions, but further reductions are needed due to increasing concern over climate change and local air pollution. Using novel 14C techniques, we have shown that most of the soot is derived from the natural gas, rather than the diesel pilot fuel. Shock-tube experiments have shown that the net soot formed from an auto-ignited fuel jet is highly intermittent. Insights from this fundamental work were used in the invention of a new fuel injector.

Supercritical Water Oxidation (SCWO) 
UBC has built and commissioned the largest Canadian SCWO pilot plant, the only one in the world designed for heat transfer and fouling research. Since building this system, my group has published the first turbulent flow fouling and heat transfer measurements for salt-water and oxygen-water mixtures. Former student Dr. M. Khan developed an elegant technique for studying foulant deposits and correlating the structure to flow conditions in the pipe. Former student Dr. E. Asselin studied the corrosion during SCWO of ammoniated solutions.

Energy Conservation and Air Quality in “Green Buildings” 
With students co-supervised by Dr. Atibaki and colleagues in IRES at UBC, I have started several new projects investigating the trade-offs between energy use and air quality in commercial buildings in Vancouver. The famous “sick-building” issue has some possible new twists as systems such as “living wall” biofilters are added and building fresh-air intake is reduced.