In one experiment, a new dramatic illustration shows why it is good to wear a face mask to prevent the spread of the new Corona virus, in high resolution.
Where imaging revealed that without a mask, the drops produced during coughing can travel up to 3.7 meters, but with the mask, the distance is reduced to just a few centimeters at best.
This simulation, described on June 30 in Physics of Fluids, reveals that some cloth masks work better than others to stop the spread of potentially contagious drops.
“The images used in our study can help push public opinion to guidelines and recommend the use of face masks,” said study author Siddhartha Verma, associate professor at the College of Engineering and Computer Science at Florida Atlantic University.
To simulate a cough, the researchers connected the head of the test model to the fog machine (which creates steam from water and glycerin), and used a pump to flush the vapor through the mouth of the model. Then visualize the steam droplets using a created “laser board” by passing a green laser pointer through a cylindrical bar. Thus, the cough appears as a green, glowing vapor that flows from the mouth of the pattern.
The researchers then placed several types of non-medical masks on top of the model to test their effectiveness in “coughing”.
They found that without covering the face with the mask, the cough went off into simulation up to 12 feet (3.7 meters) in 50 seconds.
While the home-stitched cotton mask, with its multiple layers and tight fit, reduces the spread of the drops further, although there is some leakage in the top of the mask between the nose and the cloth.
When the test model wore the monolayer mask, the cough droplets reached about 6.35 cm in front of the face.
The conical mask also worked well, as the cough drops traveled about 20 cm from the face.
However, the monolayer mask, and the folded napkin were less effective, as the drops leaked through the mask material and traveled more than one meter.
The authors write in their paper that “although the non-medicinal masks tested in this study experienced varying degrees of infiltration, they are likely to be effective in stopping large respiratory drops” from dispersion.