George Washington University researchers Jimmy Saw, assistant professor of microbiology at the Columbian College of Arts and Sciences, and Zhengtian Xu, assistant professor of civil and environmental engineering at the School of Engineering and Applied Science, each received Faculty Early Career Development Program (CAREER) awards from the National Science Foundation (NSF).
The award is the federal agency’s most prestigious honor supporting research led by junior faculty who have the potential to serve as academic role models and to lead advances in their fields. The projects are funded over five years.
Currently, 17 GW faculty—including Saw and Xu—have active CAREER awards.
“Among our community of leading scholars, NSF CAREER awardees stand out for their contributions and impact,” said Interim Vice Provost for Research Robert H. Miller. “GW’s growing cohort of current and former CAREER award recipients is further evidence of the university’s leadership in science and engineering.”
In his Microbial Diversity Lab, Saw’s team explores the diversity, ecology and evolution of microbes in extreme habitats—like hot springs, caves and hydrothermal vents near volcanoes or along the ocean floor. These intense environments resemble early Earth conditions where life may have originated. Studying microbes that continue to live there billions of years after they first evolved can offer glimpses into the evolution of more advanced organisms, Saw explained.
“They are, in a way, a snapshot that allows us to go back in time to learn more about early life on Earth,” he said.
For his CAREER award research, Saw will travel through the western United States— from southwest sites in Arizona and New Mexico up through Wyoming, Montana and Idaho and along the West Coast states—to collect samples of Asgard archaea, a group of microbes that may hold keys to understanding the diversification of life on earth.
Asgard archaea are the closest currently discovered living relatives of eukaryotes—cells or organisms that possess a clearly defined nucleus and serve as the basis of life for all animals, plants, fungi and many other organisms. While Asgard archaea likely originated in harsh thermophilic environments like hot springs or hydrothermal vents, they later adapted and can now be found in more stable habitats, including lakes, estuaries and deep-sea sediments.
Still, Saw said the thermophilic Asgard groups are poorly represented in the research record. Along with a team of postdoctoral researchers, graduate and undergraduate students and high school interns, Saw hopes to fill that scientific gap by sequencing DNA from hot spring sediment samples to measure the genetic diversity of these archaea. The team will then compare them to other forms of life.
Without the support of the CAREER award, “it would be extremely difficult to proceed with this research,” Saw said. “This award will transform the research in ways that simply wouldn’t have been possible.”
Xu’s Sustainable Urban Mobility (SUM) Lab focuses on mathematical modeling, optimization and operations management of urban transportation systems, aiming to understand, promote and regulate emerging urban mobility services and vehicle technologies. Xu’s CAREER project focuses on the “final 50 feet” of the urban delivery process, the importance of which is evident to anyone who’s ever received an Amazon package (or tried to navigate around someone delivering one). This is the stage at which delivery drivers approach their destination, hunt for parking, navigate across sidewalks for pickups and drop-offs and finally return to their vehicles.
As online shopping has exploded in popularity—in March 2022, New York City saw daily deliveries of 3.6 million packages, or roughly one package for every two residents—this final stage has become more critical and challenging than ever. Drivers may have to circle a neighborhood repeatedly in search of parking and eventually resort to unauthorized parking spaces or double parking—clogging streets, frustrating other drivers, causing increased urban air pollution and wasting their own limited time.
Xu’s CAREER project will develop novel solutions to the problems posed by the “final 50 feet” by examining the intricate connections between three focus areas—humans, machines and the environment in which they operate. Human deliverers “are the executors of the ‘final 50 feet,’ and their role in the process is undoubtedly the most critical and consequential,” Xu said. With that in mind, the project will delve into these drivers’ experiences, exploring how they adapt to and navigate challenges, how these challenges are interconnected and how these interconnections may lead to unexpected system-level effects.
On the level of machines, the project will examine nontraditional delivery solutions, including autonomous and non-autonomous vehicle alternatives like drones and lightweight micromobility devices like two- and three-wheelers. They will identify optimal operational models for these machines and determine the urban settings in which they are most effective or unnecessary.
Finally, they’ll study the world of system logistics. How do various curb uses, system management techniques and municipal regulations affect the “final 50 feet”? Pittsburgh, for instance, has introduced smart loading zones with occupancy sensors that detect real-time usage and allow drivers to check availability through a mobile app. These spaces also utilize a graduated pricing model that prioritizes short-term usage. In Philadelphia, parking apps now empower users to reserve loading zone spaces 15 minutes before arrival—but strict enforcement of metered parking and penalties for violation may incentivize drivers to resort to less-monitored, potentially unregulated alternatives. By evaluating and reimagining these system dynamics, Xu said, he and his team hope “to redefine the working mechanisms of the ‘final 50 feet’ in urban logistics, paving the way for a more efficient and robust model.”
“My research goal is to exercise elegant and parsimonious ways of describing, understanding and highlighting the fundamentals of phenomena and concepts in transportation,” Xu said. “This CAREER award offers precise opportunities to put my philosophy into practice by modeling and exploring new possibilities in the ‘final 50 feet’ of urban logistics, formulating strategies to leverage their strengths while mitigating their negative impacts on society and daily life. Through this project, we strive to develop a suite of models and tools that will be useful to the research community, students, professionals and public agencies in understanding and harnessing the evolving urban mobility system in the long run.”