Disposable Helmet Retains Cough Droplets, Minimizes Transmission to Dentists, Otolaryngologists

Dentists and otolaryngologists are at particular risk of infection of COVID-19, since they need direct access to the mouth, nose, and throat of patients. The current solutions are expensive, not highly effective, and not very accessible. In Physics of Fluids, researchers discuss their design of an open-faced helmet for patient use that is connected to a medical-grade air filtration pump from the top that creates a reverse flow of air to prevent cough droplets from exiting the helmet.

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Hand-Held Device Measures Aerosols for Coronavirus Risk Assessment

Understanding aerosol concentrations and persistence in public spaces can help determine infection risks. However, measuring these concentrations is difficult, requiring specialized personnel and equipment. Now, researchers demonstrate that a commercial hand-held particle counter can be used for this purpose and help determine the impacts of risk-reducing measures, like ventilation improvements. They describe the quick and easy, portable process in the journal Physics of Fluids.

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The Mask Matters: How Masks Affect Airflow, Protection Effectiveness

Even though it has been widely known that wearing a face mask will help mitigate the community spread of COVID-19, less is known regarding the specific effectiveness of masks in reducing the viral load in the respiratory tracts of those wearing them. In Physics of Fluids, researchers examined the effect of wearing a three-layer surgical mask on inspiratory airflows and the mask’s effects on the inhalation and deposition of ambient particles in the upper respiratory airways.

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Fast Walking in Narrow Corridors Can Increase COVID-19 Transmission Risk

Simulations have been used to predict droplet dispersal patterns in situations where COVID-19 might be spread and results in Physics of Fluids show the importance of the space shape in modeling how droplets move. The simulations are used to determine flow patterns behind a walking individual in spaces of different shape. The results reveal a higher transmission risk for children in some instances, such as behind quickly moving people in a long narrow hallway.

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Face Masks Slow Spread of COVID-19; Types of Masks, Length of Use Matter

Using face masks to help slow the spread of COVID-19 has been widely recommended by health professionals. This has triggered studies of the materials, design, and other issues affecting the way face masks work. In Physics of Fluids, investigators looked at research on face masks and their use and summarized what we know about the way they filter or block the virus. They also summarize design issues that still need to be addressed.

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COVID-19 Virus Survives on Surfaces Within Thin Film

To find out how the COVID-19 virus survives on surfaces, researchers in India are exploring the drying times of thin liquid films that persist on surfaces after most respiratory droplets evaporate. While the drying time of typical respiratory droplets is on the order of seconds, the survival time of the COVID-19 virus was found to be on the order of hours. In Physics of Fluids, the researchers describe how a nanometers-thick liquid film clings to the surface, allowing the virus to survive.

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Plasma Treatments Quickly Kill Coronavirus on Surfaces

Researchers from UCLA believe using plasma could promise a significant breakthrough in the fight against the spread of COVID-19. In Physics of Fluids, modeling conducted showed strains of the coronavirus on surfaces like metal, leather, and plastic were killed in as little as 30 seconds of treatment with argon-fed, cold atmospheric plasma. The researchers used an atmospheric pressure plasma jet they built with a 3D printer to spray surfaces that were treated with SARS-CoV-2 cultures.

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Valves on N95 Masks Do Not Filter Exhaled Droplets

Matthew Staymates, fluid dynamicist at the National Institute of Standards and Technology, is studying different mask types to determine which are the most effective at reducing disease transmission. In Physics of Fluids, he describes exploring the basic flow dynamics of N95 masks with or without exhalation valves. To do this, he generates stunning video from his schlieren imaging, a method to visualize the fluid flow away from the surface of an object, and light scattering.

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Tracking Flight Trajectory of Evaporating Cough Droplets

The ongoing COVID-19 pandemic has led many to study airborne droplet transmission in different conditions and environments, and in Physics of Fluids, researchers from A*STAR conducted a numerical study on droplet dispersion using high fidelity air flow simulation. The scientists found a single 100-micrometer cough droplet under wind speed of 2 meters per second can travel up to 6.6 meters and even further under dry air conditions due to droplet evaporation.

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Squid Jet Propulsion Can Enhance Design of Underwater Robots, Vehicles

Squids use a form of jet propulsion that is not well understood, especially when it comes to their hydrodynamics under turbulent flow conditions. Discovering their secrets can help create new designs for bioinspired underwater robots, so researchers are exploring the fundamental mechanism. They describe their numerical study in Physics of Fluids; among their discoveries, they found that thrust production and efficiency are underestimated within laminar, or nonturbulent, flows.

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Aerosol Microdroplets Inefficient Carriers Of COVID-19 Virus

Aerosol microdroplets do not appear to be extremely efficient at spreading the virus that leads to COVID-19. While the lingering microdroplets are certainly not risk-free, due to their small size they contain less virus than the larger droplets that are produced when someone coughs, speaks, or sneezes directly on us, said researchers at the University of Amsterdam’s Van der Waals-Zeeman Institute. The results were published in Physics of Fluids.

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COVID-19 Cough Clouds in Closed Spaces

As the pandemic continues, researchers have increasingly focused on the extent to which respiratory droplets carrying the coronavirus travel and contaminate the air after an infected person coughs. While scientists have studied the properties of air at the mouth, less is known about how these properties change as the cough cloud travels. In Physics of Fluids, researchers estimate the evolving volume of the cough cloud and quantify the reduction in its volume in the presence of a face mask.

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