Richard C. Flagan | |
---|---|
Born | 1947 (age 76–77) |
Alma mater | University of Michigan Massachusetts Institute of Technology |
Scientific career | |
Fields | Atmospheric science, Chemical engineering |
Institutions | California Institute of Technology |
Doctoral advisor | John P. Appleton |
Richard Charles Flagan (born 1947) is an American chemical engineer known for his research on aerosols, both in atmospheric science studies and in the processing of materials. He is the McCollum-Corcoran Professor of Chemical Engineering and Environmental Science and Engineering at the California Institute of Technology. [1]
Flagan has contributed to advancements in aerosol measurement techniques, such as the development of the scanning mobility particle sizer and mobility analyzers, which enable the study of particle size distributions undergoing rapid evolution down to 1 nm in diameter. [2] [3] [4]
Flagan received his B.S.E. in mechanical engineering from University of Michigan in 1969 and S.M. and Ph.D. degrees from Massachusetts Institute of Technology in 1973, also in mechanical engineering. [1] [4] His Ph.D. dissertation was titled The formation of nitric oxide from organic nitrogen contained in fossil fuels. [5] During his doctoral research he studied combustion of kerosene doped with pyridine or pyrrole to simulate burning of fuel oil. His studies revealed that turbulent mixing influences nitric oxide (NO) emissions from organic nitrogen in fossil fuels, with poor initial fuel-air mixing leading to lower NO concentrations. Exploring the interaction between chemical kinetics and turbulent mixing, he was able to develop a model that predicted NO emissions by incorporating it into a model which took into account flow non-uniformities in the burner where the reactions were occurring. [5]
Flagan joined California Institute of Technology (Caltech) in 1975 as an assistant professor in the environmental engineering science program within the Division of Engineering and Applied Science. [1] [6] Both Sheldon K. Friedlander, who moved to UCLA, and John H. Seinfeld who was a frequently collaborator at CalTech, influenced him to move from focusing on combustion and turbulent reacting flows, to focusing on aerosols. [6]
In 1981 Flagan became associate professor and was promoted to full professor in 1986. [1] Over time, his research interests expanded beyond environmental research questions. While he initially studied particle formation in combustion systems and photochemical smog, he later collaborated with JPL on using aerosols to refine silicon for more efficient photovoltaic production. With this shift in focus he transferred to the Chemical Engineering department in 1990. [6] His research advanced aerosol measurement techniques, enabling detection and analysis of different sizes and compositions of atmospheric particulates. [7] He holds at least 25 patents for his invented instruments and various aerosol reactor technologies. [4] [8]
In 2000, as his work was more inline with the Environmental Engineering Division he re-established his formal affiliation with the program and at that time was appointed to an endowed professorship with the full title Irma and Ross McCollum-William H. Corcoran Professor. [1]
Flagan was president of the American Association for Aerosol Research from 1996-1997 [9] and is editor-in-chief emeritus of the journal Aerosol Science and Technology. [10] He was elected to the National Academy of Engineering in 2010 [11] and is a member of the board of directors of the California Council on Science and Technology. [4]
Flagan has been interviewed as an expert for articles discussing particulates and aerosols. In a New York Times piece on dust, he explained how particle size affects how fast dust falls, why a damp cloth is an effective dust remover and why the centrifugal windstorm generated by bagless vacuum cleaners are unlikely to pick up most small particles. [12] In an Associated Press article during the COVID-19 pandemic, he advised using an N95 mask for two or three days, emphasizing that duration of use is more critical than frequency. He noted that the mask's performance degrades as particles accumulate on it. [13]
Smoke is a suspension of airborne particulates and gases emitted when a material undergoes combustion or pyrolysis, together with the quantity of air that is entrained or otherwise mixed into the mass. It is commonly an unwanted by-product of fires, but may also be used for pest control (fumigation), communication, defensive and offensive capabilities in the military, cooking, or smoking. It is used in rituals where incense, sage, or resin is burned to produce a smell for spiritual or magical purposes. It can also be a flavoring agent and preservative.
An aerosol is a suspension of fine solid particles or liquid droplets in air or another gas. Aerosols can be generated from natural or human causes. The term aerosol commonly refers to the mixture of particulates in air, and not to the particulate matter alone. Examples of natural aerosols are fog, mist or dust. Examples of human caused aerosols include particulate air pollutants, mist from the discharge at hydroelectric dams, irrigation mist, perfume from atomizers, smoke, dust, sprayed pesticides, and medical treatments for respiratory illnesses.
Soot is a mass of impure carbon particles resulting from the incomplete combustion of hydrocarbons. It is more properly restricted to the product of the gas-phase combustion process but is commonly extended to include the residual pyrolysed fuel particles such as coal, cenospheres, charred wood, and petroleum coke that may become airborne during pyrolysis and that are more properly identified as cokes or char.
In atmospheric chemistry, NOx is shorthand for nitric oxide and nitrogen dioxide, the nitrogen oxides that are most relevant for air pollution. These gases contribute to the formation of smog and acid rain, as well as affecting tropospheric ozone.
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John Hersh Seinfeld is an American chemical engineer and pioneering expert in atmospheric science. His research on air pollution has influenced public policy, and he developed the first mathematical model of air quality, which has influenced air pollution tracking and research across the United States. He has spent his career at the California Institute of Technology, where he is currently the Louis E. Nohl Professor of Chemical Engineering.
A scanning mobility particle sizer (SMPS) is an analytical instrument that measures the size and number concentration of aerosol particles with diameters from 2.5 nm to 1000 nm. They employ a continuous, fast-scanning technique to provide high-resolution measurements.
An aerodynamic aerosol classifier (AAC) is an embodiment of a measurement technique for classifying aerosol particles according to their aerodynamic diameters.
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