Five Young Faculty Members Win NSF’s CAREER Awards

Five SEAS assistant professors have received the National Science Foundation’s prestigious CAREER Awards, given to young researcher-educators to support their novel research. The recipients are:  José Blanchet, in the Department of Industrial Engineering and Operations Research;  Marco J. Castaldi and Kartik Chandran in the Department of Earth and Environmental Engineering;  V. Faye McNeill, in the Department of Chemical Engineering, and Nabil Simaan, in the Department of Mechancial Engineering.

José Blanchet
José Blanchet’s grant will support research to provide new tools for risk assessment for the financial markets. “Events such as environmental or natural disasters, major market crashes, pension and insurance breakdowns, and terrorist attacks are rare but consequential events,” says Blanchet. “I hope to develop new and efficient computational tools for risk assessment of rare events that exhibit features such as heavy-tails, complex dependence and incorporation of combinatorial objects.”

“Efficient evaluation of rare-event probabilities can provide decision makers with key quantitative policy assessment metrics and insights,” he says. Examples include assessing ruin probabilities for purposes of sizing the capital reserve of insurance and financial companies and computing the probability that a target is able to evade a set of detectors as well as its conditional most-likely location.

Blanchet will develop a framework that exploits asymptotic analysis, expressed at a coarse scale, to systematically generate efficient rare-event simulation algorithms for complex stochastic systems, which must necessarily be implemented at a fine scale. Blanchet’s proposal, Efficient Monte Carlo Methods in Engineering and Science: From Coarse Analysis to Refined Estimators, will receive $400,000 in funding. 

“My strategy consists in connecting large deviations analysis with algorithmic design of efficient simulation estimators,” says Blanchet. “One key tool that I will employ in the design and performance analysis of these algorithms is a systematic use of Lyapunov bounds for Markov chains, combined with parametric families of importance sampling distributions.”

He will study five types of environments that exhibit stylized features that have not been well studied in rare-event simulation. They are: 1) stochastic recursions with heavy-tails, which are used to model insurance risk and reservoir processes; 2) heavy-tailed queues, which arise in database and networking applications; 3) counting problems and inference for combinatorial structures, which arise in sociology and biology; 4) location of objects immersed in a random medium, with a particular emphasis on military applications to find targets that have eluded detection for a long period of time, and 5) random fields, which arise in oceanography, environmental studies and medical imaging.

Marco J. Castaldi
Marco J. Castaldi, assistant professor of earth and environmental engineering, will investigate the chemical kinetics and mechanisms of catalytic reactions by combining a high pressure shock tube, normally used for homogeneous reaction analysis, and adapting it to study heterogeneous reactions. In the process, he has created the first-ever catalytic shock tube. This research holds the promise of understanding the reactions to efficiently produce synthesis gas—a gas used as a feedstock for clean liquid fuel production—from greenhouse gases.

“This technique will resolve the mechanistic uncertainties that have evolved using conventional continuous flow systems,” he says. For example, this new technique will provide a way to detect and quantify key oxygenated intermediates, such as methanol and formaldehyde, to guide the design of new reactors to produce synthesis gas, or syngas, in a more efficient manner.  “Resolving these uncertainties should lead to potentially significant impacts on energy generation, the quality of the environment, and efficient catalytic reactor technology development.”

Castaldi’s new technique incorporates a catalyzed short contact time (SCT) reactor substrate and a shock tube that can operate at targeted pressures and temperatures, reproducing actual operating conditions. This combination of SCT reactor and shock tube enables the study of the mechanism of complex heterogeneous reactions over a catalyst for well-defined times and conditions. By understanding these processes using the catalytic shock tube, there will be a much smoother scale-up from the lab environment to industrial applications, where high pressures are necessary for increased process throughput. 

“This innovative technique will investigate the chemical kinetics and mechanisms of environmentally important catalytic partial oxidation reactions and greenhouse gas reforming reactions,” says Castaldi. “First, it will add to our understanding of the mechanism of catalytic partial oxidation of methane to synthesis gas, and second, it will help to optimize the process of reforming methane to reduce the amount of greenhouse gases in the air and, hopefully, identify paths for the beneficial utilization of these gases.”

“The attributes of the apparatus center on eliminating transport interactions, thus allowing intrinsic kinetic data to be obtained. It will provide a true step change from ambient to the desired reaction conditions for precisely defined time durations for well characterized, real catalytic reactors. Moreover, it has the capability to conduct temperature- and pressure-jump relaxation experiments. Currently there is no other gas-solid chemical kinetic method that can achieve this,” says Castaldi.

Kartik Chandran
Kartik Chandran, assistant professor of earth and environmental engineering, will be researching molecular mechanisms and metabolic modeling of  nitrous oxide and nitric oxide emission fluxes from biological nitrogen removal reactors. His research centers on engineered wastewater treatment technologies that are enabled by environmental microbiology and biotechnology.

Chandran’s preliminary research has shown that biological nitrogen removal (BNR) processes in wastewater treatment plants may, in fact, produce gases that are environmentally hazardous. This NSF project will characterize nitrous oxide (N2O) and nitric oxide (NO)  emissions from wastewater treatment plants at the molecular mechanism and metabolic modeling levels and will complement the multi-agency funded Wastewater Treatment and Climate Change program of the Kartik Chandran Laboratories that aims to characterize N-GHG emissions from wastewater treatment plants around the world.

“My research goal is to develop BNR technologies that will improve water quality, but not at the cost of deteriorating air quality,” Chandran says. “The greenhouse impact of nitrous oxide is about three hundred times that of carbon dioxide. In addition, nitric oxide is converted to nitrogen dioxide in the atmosphere, and that is one of the primary constituents of the orange smog present during peak air pollution events in urban areas.”

Chandran is collaborating with colleagues at Technical University-Delft in The Netherlands on a complementary project to find the underlying molecular mechanisms that lead to N2O and NO generation by nitrifying bacteria, which are key protagonists in BNR reactors.

V. Faye McNeill
V. Faye McNeill, assistant professor of chemical engineering, received her CAREER award to research a better understanding of the influence of ice and snow on atmospheric composition and climate. Her proposal, The Atmospheric Chemistry of Ice and Snow, will be funded for five years. Her plan is to address a major challenge in atmospheric chemistry: understanding and quantifying the interactions of ice and snow with trace gases.

“Ice in the environment, in the form of ice particles in clouds, or sea ice and snow at the Earth’s surface, has a profound influence on atmospheric composition and climate,” says McNeill. “A quantitative physical understanding of trace gas-ice interactions is critical for predicting the effects of climate change on atmospheric composition, for the interpretation of ice core chemical records, and for modeling atmospheric chemistry.”

“There are significant gaps in our current understanding of the uptake of gases by ice, including uncertainty regarding the microphysical location of adsorbed species and the potential role of a quasi-liquid or quasi-brine layer at the ice surface,” says McNeill.

“The McNeill Group will apply a set of powerful, complementary experimental and modeling approaches in order to gain new chemical and physical insight into these gas-ice interactions in the environment and their effects on atmospheric composition.”

The results of these studies will enable researchers to more accurately constrain the effects of snow and ice chemistry on atmospheric composition for use in coupled atmospheric chemistry-Earth system models. The group’s research efforts will be complemented by an integrated education and outreach program designed to help New York City students from kindergarten through high school better understand the science behind our changing environment.

Nabil Simaan
Nabil Simaan, assistant professor in the Department of Mechanical Engineering and director of the Advanced Robotics and Mechanism Applications (ARMA) Laboratory, received his CAREER Award to advance his work developing novel, flexible snake-like robots and parallel robots that will improve success of future minimally invasive surgery paradigms. These robots will gauge their force interactions with the patient’s anatomy, gather information, and then act on that information. 

One of the latest surgical paradigms is NOTES, Natural Orifice Trans-luminal Endoscopic Surgery, which uses the natural openings in the body to reach the affected organ and perform surgery on it. Unfortunately, current surgical systems are bulky and cannot support these new surgical paradigms. There is a need for new down-scalable surgical robots that provide access to the deepest anatomical organs with minimal damage to surrounding anatomy. For example, one could think of performing surgery on the abdomen by reaching through the patient’s mouth, past the esophagus, and through an incision in the stomach. Such robots will be of little use if they are not equipped with some basic forms of intelligence – another aspect addressed by Simaan’s CAREER proposal.

“My surgical robots will be able to perform many other surgical functions,” says Simaan, “and they will safeguard against damage to the anatomy by acting as intelligent intervention and information-gathering tools for assisting surgeons during increasingly complex procedures. The objective of this research is to provide the theoretical foundation for modeling and control of flexible robots for intelligent and safe interaction with the anatomy.” “Intelligence” in this case refers to the ability of these robots to gauge their force interaction with the anatomy, gather information about the anatomy, and act based on this information, he says.

Screw theory and stochastic estimation methods are used for modeling the ability of these robots to estimate their wrench interaction with the anatomy by using intrinsic and extrinsic sources of information. These performance measures are used in hybrid force control algorithms that allow characterizing shape, stiffness, and anatomical constraints governing safe maneuvering of suspended organs.

“This research will advance the field of robotics by addressing control and resolution of multi-point contact problems for compliant insertion control and bracing against soft environments,” says Simaan. “It promises to revolutionize medical robotics by introducing novel algorithms for designing and controlling surgical robots capable of safe interaction and manipulation of the patient’s anatomy.”