Barrier, heal thyself

Paul Raven @ 16-09-2010

Add some bacteria to your concrete mixture, and you get walls that heal themselves:

The researchers found just the right candidates: a hardy bunch of spore-forming bacteria belonging to the genus Bacillus that make a great living in the alkaline soda lakes of Russia and Egypt. Jonkers and his colleagues placed the spores and their food source, calcium lactate, into small ceramic pellets to prevent them from being activated prematurely by the wet concrete mix and adversely affecting the integrity of the material. The spores remained dormant until the formation of a crack allowed water to sneak in, waking the bacteria and their appetite. As they began to chow down, gobbling up the calcium lactate and water, they also began to pump out calcite (a very stable form of calcium carbonate), which quickly went to work filling up the holes. Now that they’ve successfully tested the bacteria’s mettle, Jonkers and his co-workers plan on comparing the strength of their natural concrete to that of the real thing.

Regular readers may remember that this is an idea we’ve seen before.


Nanotechnologically self-repairing circuits

Tom James @ 11-09-2009

selfheal_x220Researchers at the University of Illinois have developed a means by which nanotube-filled capsules could repair electronic circuits when they are damaged:

Capsules, filled with conductive nanotubes, that rip open under mechanical stress could be placed on circuit boards in failure-prone areas. When stress causes a crack in the circuit, some of the capsules would also rupture and release nanotubes to bridge the break.

“Many times when a device fails, it’s because a circuit or capacitor burns out,” says Bielawski. “This is critical in situations where you can’t repair it — in satellites or submarines.” To address the problem, engineers currently build redundancy into a system. Self-healing circuits could make devices for remote applications more lightweight, more efficient, and cheaper, says Bielawski.

Consumer electricals have become increasingly cheap and disposable over the past few years. If this technology is adopted widely and improved could it lead to electricals that continue to function well for many decades? It seems unlikely that companies would choose to lose built-in obsolesence as a marketing tool, but if technologies increase in durability and strictly hardware-based improvements tail off (i.e. it becomes more economical to achieve improvements in performance through software tweaks, instead of relying on Moore’s Law) could it be that we find ourselves with the same mobile-phone/$multi-purpose_personal_electronic_widget for many years, which continually repairs and rebuilds itself when damaged?

[from Technology Review][image from Technology Review]