In this eighth installment of a 14-part series of monthly articles, The Combustion Institute recognizes the 2017 Distinguished Papers selected from among the scientific papers presented during the 36th International Symposium on Combustion. Congratulations to Anton D. Sediako, Charles Soong, Jane Y. Howe, Mohammad Reza Kholghy, and Murray J. Thomson for winning the DPA in the Soot, Nanoparticles, PAH and Other Large Molecules colloquium.

The authoritative paper, Real-time observation of soot aggregate oxidation in an Environmental Transmission Electron Microscope, explores how particulate oxidation during combustion effects the size and structure of oxidized particulate matter. The scientific team used a new Environmental Transmission Electron Microscope (ETEM) technique to view oxidation of particles in real time at the nanometer scale.

Particulate matter such as soot is an important air pollutant that has attracted a lot of attention from international scientific communities. Most people know soot released into the atmosphere from combustion has adverse effects on the environment, human health, and inhibits engine performance and efficiency. The size and structure of the particle emissions, however, is a determining factor in health effects. Soot emissions are determined by the difference between the amount of soot formed in the flame and the amount oxidized in the flame. The scientific team’s paper has advanced understanding of the different oxidation processes inside of the ETEM instrument. That observation process provided a unique and novel opportunity to track individual soot aggregates in real time, and visualize their internal/surface oxidation, structural changes, and fragmentation.

The immediate impact of the paper provides a better understanding how particulate oxidation effects the  particle’s size and structure. In the long-term, the scientific team aimed to develop a new experimental technique, and a way of shining a light onto unknown areas of soot formation and emissions. Scientists believe the impact of this new technique goes well past the immediate study on oxidation – as it gives a direct, recorded, view of what is occurring at the atomic scale. Without asking for complex analysis, trust or interpolation, the team can see what happens in real time.

The techniques developed in this work directly benefit combustion researchers who study combustion, material science, and nanomaterials. Engineers will also use this research to build upon processes to reduce particulate matter from engine processes. Engine designers in multiple industries will be able to use the scientific team’s research to design more improved technologies. The public’s health will greatly benefit from these efforts to lower particulate levels in the atmosphere.

The paper’s research was conducted at the University of Toronto, Canada. By partnering with Hitachi Higher Technologies Canada, and Ontario Center for Characterization of Advanced Materials (OCCAM), the scientific team’s lab was able to develop a technique to directly observe single nanoparticles as they react, burn, or changes in structure. Mechanisms and questions regarding the oxidation pathways were then answered with experimental video data.

For the first time, the team was able to record how soot particles break apart, how pores form during burnup, and directly measure the reaction rates. These findings and capabilities exceeded the initial goals of the project well past simple reaction observation. Research for the paper began in September 2015 and was completed by November 2016.

About 1,300 papers were submitted to the 36th Symposium in 14 combustion science colloquia. Those papers were categorized by teams of colloquium coordinators and co-chairs, and then distributed to approximately 1,000 scientific reviewers. One paper in each discipline was awarded the recognition of Distinguished Paper.

The 14 Distinguished Papers undergo committee review for consideration to receive the Silver Combustion Medal that will be awarded during the 37th Symposium in Dublin, Ireland. A paper selected for this honor exemplifies quality, achievement, and significance to advance a field of combustion science. Distinguished papers are selected biennially from among the scientific papers presented during the International Symposium on Combustion and accepted for publication in the Proceedings of The Combustion Institute.