How to protect the grocery line, classroom and orchestra from COVID


Despite effective vaccines, it has become clear that SARS-CoV-2 will not go away completely anytime soon. At the 74th Annual Meeting of the APS Division of Fluid Dynamics, physicists and engineers will showcase innovative ways to avoid coronavirus clouds, whether standing in line, going to class, by listening to the opera or meeting people elsewhere.

Researchers will share the latest findings on reducing viral transmission indoors in crowded environments and answer questions from reporters during a live virtual press briefing on Monday, November 22, 2021 from 2:30 p.m. to 3:30 p.m. KST. United States Rockies (MST).

One of the researchers, physicist Varghese Mathai of the University of Massachusetts at Amherst, and his group mounted 3D printed mannequins on a conveyor belt to model the flow of air in a line of people.

They studied how waiting in a queue for prescriptions or groceries is more than a boring activity – it is also a very poorly studied place that can be a hotbed for pathogens spreading from human to human. .

“This study establishes some of the counterintuitive airborne transmission mechanisms that exist in public queues – from voting lines, to supermarket and airport lines, to COVID-19 test lines,” said Mathai.

They found that periodic movements – when the entire line moves a person forward – can actually cause aerosol transmission.

“We are proposing strategies to reduce this cross-contamination, measures that go beyond the six-foot guideline currently in place,” said Ruixi Lou, an undergraduate student who works with Mathai.

As winter approaches, classrooms are another area of ​​concern for viral transmission. Opening windows is often impossible due to cold temperatures and forced ventilation is often prohibitive. As a result, the health risks are high.

“Dead zones can form in ventilated spaces and could become breeding grounds for airborne disease,” said Rao Kotamarthi, senior scientist and air quality expert at the Argonne National Laboratory. “If small aerosol particles containing a high viral density accumulate in these regions, an entire class could be infected. “

Kotamarthi and his group from Argonne and the University of Illinois at Urbana-Champaign will share early results at the meeting.

The simulations show that heating in winter and air conditioning in summer affects the size of dangerous dead zones in different ways. The temperature difference between the incoming air and the air inside a room reduces air mixing where students are seated.

“We are suggesting cost-effective ways to improve ventilation and mixing and stem the spread of airborne disease in classrooms,” Kotamarthi said.

At the start of the pandemic, researchers found that singing and wind instruments were aggressively spitting out respiratory droplets. Now, a collaboration between Princeton University, the University of Montpellier and the Metropolitan Opera Orchestra has developed new ways to safely enjoy live musical performances.

Opera singers and professional musicians performed live, and scientists followed their exhaled tunes. Surprisingly, the singers’ intense breathing control meant that they generally generated slower, safer airflows than an ordinary person would.

“Within an orchestra, we identify a few situations where rapid air jets could promote the transport of pathogenic droplets and lead to an increased risk of contamination. Rapid airflows can be greatly reduced by using a face mask and covering the bell of wind instruments, ”said Philippe Bourrianne, postdoctoral engineer at Princeton, who will present the study.

The study was accepted by Physical Review Fluids.

Viral spread, however, is not limited to specific places like an opera house. Wherever you meet people, there is a risk that they (or you) will transmit a disease like COVID-19. Alfredo Soldati, director of the Institute of Fluid Mechanics at TU Wien, therefore led a virus exposure mapping project in different seasonal environments, with varying temperatures and humidity levels.

“By providing visualizations of the spatial distribution of copies of the virus, we highlight the high risk of infection associated with droplets that remain airborne near an infected individual,” he said. .

In a post released earlier this fall, Soldati and his colleagues at the University of Padua, the Okinawa Institute of Technological Sciences and his own institution used simulations to create maps showing where clouds form. Of respiratory droplets in a wide range of scenarios.

“We have developed an efficient yet simple framework capable of predicting the risk of infection under different environmental conditions and respiratory activities,” Soldati said.

/ Public distribution. This material from the original organization / authors may be ad hoc in nature, edited for clarity, style and length. The views and opinions expressed are those of the author (s). See it in full here.

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