Posts Tagged ‘steel’

Coronavirus could live up to three days on a plastic or stainless steel doorknob, researchers found.

A preliminary study released last week also showed that the virus could be aerosolized, meaning it could potentially live in the air. It could live up to three days on some surfaces.

Though it’s widely acknowledged that coronavirus could be spread via respiratory droplet — the result of coughing or sneezing — there’s not much information yet on how the virus lives on surfaces or in the air.

The new research could inform cleaning recommendations and other measures taken to reduce community spread.

The U.S. Centers for Disease Control and Prevention recommend routine cleaning of high-touch surfaces, like door handles, high-backed chairs, light switches and remote controls.

The study, released last week, is not yet peer-reviewed. That means that other experts have not had the chance to check the quality of the research, and its not advised that doctors use it in a clinical setting. But as people try to cope with the disease, it’s being widely read.

Here’s how long the study indicated the virus could live on various surfaces:

The air: Researchers found the virus could be detected in aerosols up to 4 hours after it was sprayed.

Copper: Up to 4 hours

Cardboard: Up to 24 hours

Plastic: 2-3 days

Stainless steel: 2-3 days

https://www.cleveland.com/news/2020/03/coronavirus-update-virus-could-live-up-to-24-hours-on-cardboard-3-days-on-plastic-and-steel-study-says.html?utm_source=Newsletter&utm_medium=Newsletter%20-%20Wake%20Up&utm_campaign=Newsletter:%20The%20Wake%20Up


A new wood-compacting process crushes the gaps between cell walls in natural wood (porous structure seen in the scanning electron microscopy image, left), making the densified wood (right) as strong as steel.

Newly fabricated superstrong lumber gives a whole new meaning to “hardwood.”

This ultracompact wood, described in the Feb. 8 Nature, is created by boiling a wood block in a water-based solution of sodium hydroxide and sodium sulfite. The chemicals partially strip the wood of substances called lignin and hemicellulose, which help give wood its structure and rigidity. Then the block gets squeezed between metal plates heated to 100° Celsius at a pressure of 5 megapascals — about 50 times the pressure of sea-level atmosphere. That squashes the gaps between the cell walls in the wood, shrinking the block to about 20 percent its original thickness and making it three times denser.

Researchers found that the densified wood could withstand being stretched or pulled 11.5 times harder than its natural counterpart without breaking. That makes it about as strong as steel, even though it’s more lightweight. Stainless steel pellets fired from an air gun and moving at 30 meters per second easily busted through a typical wooden plank, but got lodged in a stack of densified wood sheets with the same total thickness.

Chemicals used to process the wood work for various tree species and don’t pose any significant pollution concerns, says study coauthor Teng Li, a mechanical engineer at the University of Maryland in College Park. So this condensed wood could provide an ecofriendly alternative to steels or alloys for constructing buildings or bridges. It could also be used to manufacture more lightweight, fuel-efficient cars or trains, Li says.

J. Song et al. Processing bulk natural wood into a high-performance structural material. Nature. Vol. 554, February 8, 2018, p. 224. doi: 10.1038/nature25476.

https://www.sciencenews.org/article/superdense-wood-lightweight-strong-steel