Patched up

I was down by Bondi pier…

SUN cream is a fickle friend. It protects against burn-inducing ultraviolet (UV) light, but only for a period. And the first most people know of when that period is up is the sickening sensation that their skin is starting to catch fire—by which time it is too late to act. But Justin Gooding of the University of New South Wales, in Sydney, Australia, now thinks he has a solution for those who might otherwise risk overdoing it on Bondi Beach: a stick-on UV sensor that can be tuned to give warning when a new slap of protection would be advisable.

Dr Gooding’s invention, described in this month’s ACS Sensors, is based on titanium oxide. This is a compound well known to shed high-energy electrons if hit by UV. When those electrons interact with water and molecular oxygen, they generate reactive groups of atoms called free-radicals. Dr Gooding suspected that these radicals could be used to trigger changes in the sorts of dyes employed to colour food.

To test this idea, he and his colleagues filled the cartridges of an inkjet printer with a series of solutions…Continue reading
Source: Economist