July 06, 2020
Enjoy these interesting stories from the scientific community.
*-- Glow-in-the-dark sneezes show best homemade face mask is quilted cotton --*
To figure what types of homemade mask best prevent the spread of COVID-19, scientists at Florida Atlantic University used glycerine and laser light to illuminate the movement of droplets from coughs and sneezes.
Researchers report the distance droplets move can be cut by more than half by using a homemade mask -- from more than 8 feet, to less than 2 feet.
For the new study, published Tuesday in the journal Physics of Fluids, researchers focused on cloth-based coverings, as most other research has focused on medical-grade masks.
"Such masks have been recommended for public use by various agencies, but there are no clear guidelines on the best material or construction technique that should be used," Siddhartha Verma, lead author and an assistant professor at Florida Atlantic, told UPI in an email.
They found that without a mask, droplets traveled more than 8 feet -- beyond the 6 feet recommended for "social distancing." With a bandana, droplets traveled 3 feet, 7 inches. With a folded cotton handkerchief, the droplets traveled 1 foot, 3 inches. The stitched quilted cotton mask proved most effective, allowing droplets from the nose and mouth to travel just 2.5 inches.
Scientists also tested a cone mask, widely available at local pharmacies. The commercial mask allowed droplets from simulated coughs and sneezes to travel 8 inches.
For the study, researchers sprayed a solution of distilled water and glycerin through the mouth of a mannequin to create glow-in-the-dark droplet clouds resembling those produced by coughs and sneezes.
Researchers projected the glow-in-the-dark coughs and sneezes through several types of homemade masks, using cameras to measure how far the droplets traveled.
"We visualized the droplets in a sheet of laser light," said co-author Manhar Dhanak, department chair, professor and director of SeaTech at Florida Atlantic. "The droplets scatter the light and hence become visible."Researchers determined that creating a tight seal and layering material were the most important factors in creating an effective barrier.
"The effectiveness of a mask does not necessarily depend on the thread-count of the fabric," Verma said.
While masks are effective in reducing the risk of transmission of viral infections, Dhanak said that "given the possibility of leakage, it is important to use a combination of social distancing, mask use, hand-washing and other recommendations from healthcare professionals in order to minimize the chances of transmission."
In future studies, Verma and Dhanak plan to more closely examine leakage around the sides of different kinds of masks and how to curtail it."We are also looking into the impact of environmental conditions in a room on the spread of the droplets and wider applications of our techniques in design of barriers, shielding and air-conditioning systems in the workplace and open-plan offices," Verma said.
*-- Astronomers measure spin-orbit alignment of a distant super-Jupiter --*
For the first time, astronomers have measured the spin-orbit alignment of a faraway super-Jupiter exoplanet, located 63 light-years from the Earth in the Pictor constellation.
The super-Jupiter exoplanet, Beta Pictoris b, has a mass 11 times that of Jupiter and enjoys an orbit around its host star similar to the trajectory Jupiter takes around our own sun.
The detailed observations of Beta Pictoris b -- shared Monday in the Astrophysical Journal Letters -- could help scientists better understand the formation and evolution of planetary systems.
"The degree to that a star and a planetary orbit are aligned with each other tells us a lot about how a planet formed and whether multiple planets in the system interacted dynamically after their formation," lead study author Stefan Kraus said in a news release.
During the 18th century, scientists Immanuel Kant and Pierre-Simon Laplace noticed that the orbital planes of the solar system's planets were largely aligned. They estimated that Earth and its planetary neighbors formed from a rotating and flattened protoplanetary disc.
"It was a major surprise when it was found that more than a third of all close-in exoplanets orbit their host star on orbits that are misaligned with respect to the stellar equator," said Kraus, professor of astronomy and physics at the University of Exeter in Britain.
"A few exoplanets were even found to orbit in the opposite direction than the rotation direction of the star," Kraus said. "These observations challenge the perception of planet formation as a neat and well-ordered process taking place in a geometrically thin and co-planar disc."
Using the GRAVITY instrument on the Very Large Telescope in Chile, scientists measured the minuscule spatial displacement caused by the stellar rotation of Beta Pictoris. The data revealed an alignment between the star's rotational axis and the orbital axis of the planet Beta Pictoris b and its surrounding debris disk.
"Gas absorption in the stellar atmosphere causes a tiny spatial displacement in spectral lines that can be used to determine the orientation of the stellar rotation axis," said study co-author Jean-Baptiste LeBouquin, an astronomer at the University of Grenoble in France. "The challenge is that this spatial displacement is extremely small: about 1/100th of the apparent diameter of the star, or the equivalent to the size of a human footstep on the moon as seen from Earth."
The latest findings showed the Beta Pictoris system is just as aligned as our own solar system, but authors of the new study suggest a wider sample size is needed to confirm how common spin orbit alignment is throughout the cosmos.
"A dedicated high-spectral resolution instrument at VLTI could measure the spin-orbit alignment for hundreds of planets, including those on long-period orbits," said Kraus. "This will help us to answer the question what dynamical processes shape the architecture of planetary systems."