What first began as a foray into the world of biology quickly changed into mechanical engineering for graduate student Oliver McRae (ENG’19). His time at BUMechE and as a student researcher in Prof. Jacy Bird’s Fluid Lab have landed him a sought-after NSF internship at the Centers for Disease Control and Prevention (CDC) in Cincinnati, Ohio.
Oliver McRae first came to BU in 2008 as a fresh-faced biology student on the pre-med track, but two years into the program, realized he wanted to switch gears and explore his options in engineering. While switching majors halfway through his program would prove to be difficult, McRae instead decided to finish up and pursue his engineering dreams in grad school–a wise decision, since he’s managed to use his combined knowledge to benefit his research. Before his junior year, he went back home to Jamaica for an internship with Red Stripe, Jamaica’s largest brewery, where he rediscovered his interest in engineering. “I was in the risk management and environmental monitoring department, but kept finding myself going over to the engineering department on a daily basis,” he says. “After a few weeks, they decided it would be best if I switched to the engineering department full time, since they saw how quickly I was able to contribute, and how much I enjoyed it. That internship made me realize that engineering was definitely what I wanted to pursue.”
McRae spent two summers at Red Stripe, and eventually came back to finish his undergraduate degree and move on to grad school, which is how he found himself in Prof. Jacy Bird’s Fluid Lab. He says, “When I first came to Jacy’s lab, it had no biology component, but the lab just happened to start working on a project with a biotech company. We started looking at fluid stresses and mammalian cells, which is when my biology background really helped.” Over time, he plans to look at the intersection between fluid mechanics and biology, bridging the gap between these two fields.
“When I first came to Jacy’s lab, it had no biology component, but the lab just happened to start working on a project with a biotech company. We started looking at fluid stresses and mammalian cells, which is when my biology background really helped.”
In Fall 2017, McRae was awarded the opportunity to pursue an internship at the Centers for Disease Control and Prevention (CDC) in Cincinnati, a setting he describes as “quite different, a lot more regimented in comparison to academia”. So far, though, he managed to find himself in a good spot, with friendly folks who stress on the importance of collaboration. “Even though everyone’s working on a lot of different projects, there’s a lot of overlap, and people are popping in and out of each other’s offices every now and then. Generally, it’s an encouraging atmosphere, and I’m happy to be here,” he states.
According to McRae, one of the CDC’s greatest strengths is their mission to improve public health. The CDC tends to be very applied, since they must focus on helping as many people as possible, and understanding how diseases affect people reasonably quickly. However, on the other end of the spectrum, engineers in academia often focus on the more fundamental and basic side of research. “When we work on a project and try to understand what governs a particular phenomenon,” McRae explains, “We might motivate it by suggesting ways it might later be used, but we may not necessarily have that direct connection when we’re doing the research. The CDC is the complete opposite. What’s great about this internship is that we’re able to take what we do best in Prof. Bird’s lab–which is try to understand at the most fundamental level what governs some of these mechanisms–and see how we can best help the CDC with their models.”
“What’s great about this internship is that we’re able to take what we do best in Prof. Bird’s lab–which is try to understand at the most fundamental level what governs some of these mechanisms–and see how we can best help the CDC with their models.”
McRae works in the Division of Applied Research and Technology at the CDC, wherein his particular group looks at aerosol transmission of both solid aerosols like dust and other particulates, and liquid aerosols and pathogen-laden droplets. While in the lab, he tends to look at a lot of bursting bubbles that can create jet droplets, the tiny droplets one might see or feel above a glass of soda. So, he and the members of his team are combining their knowledge to work on aerosol transmission modeling. He states, “What I’m working on is looking at how pathogens—viruses and bacteria—get loaded into these jet droplets, and then calculating the number of these droplets that are created, along with their size. For their models, the CDC needs to know how many of these are created per minute, or per cough or per flush, and their size distribution.” He adds, “With their focus being more applied, they tend to use more general assumptions from published research, whereas we want to give them a number that’s going to change based on temperature, humidity, and other factors so that their modeling can be even more accurate.”
Currently, McRae is working on a set of simulations using computational fluid dynamics to look at how bubble size and fluid properties are going to govern the stresses created in the liquid around these bubbles. “We don’t just want to look at the volume of fluid going into these droplets, but also at the stress history in these droplets, because that’ll affect the bacterial viability. This will help give the CDC a more accurate picture of how these pathogens are actually being transmitted,” he explains.
McRae credits a lot of his research success to Prof. Jacy Bird. When asked about his experience working in the Fluid Lab, he says, “It’s such a great work environment. I always think our lab is more like a family and not a group of co-workers. Jacy never pressures us to work long hours, but we end up being in the lab all the time anyway, because we love what we’re working on. He always says we’re the lab’s greatest assets, so anything that we need to make our time there better, he’ll provide for us. It’s truly a joy to work in Jacy’s lab.”
“I always think our lab is more like a family and not a group of co-workers.”
While he plans to graduate in 2019, McRae looks forward to continuing this research during a postdoc, and hopes to pursue a professorship. This experience has shown him that there’s many things in the field researchers are unaware of, assume, or don’t have answers to–and it’s not because some of this information is inaccurate, but because there’s room for improvement. He’s set on continuing to understand the interplay between fluid dynamics and biology, and to look at how fluid mechanics will influence the natural world. “For me, this is a career move as opposed to being part of my next project. Next, I want to analyze airborne disease transmissions–look at how pathogens are loaded into the droplets of respiratory aerosols when we cough and sneeze. This isn’t just the next few months, but hopefully decades of my research career,” he states.