Scientists have designed a “skin” that senses when concrete structures are damaged

Image: Bittbox via Flickr, reproduced under creative commons.

Concrete is pretty great, isn’t it? It’s strong, it’s cheap, it’s easy to use. Let’s hear it for concrete!

On the downside, though, it’s also prone to cracking – if there are swift changes in temperature, for example, or if it’s bearing too much weight. Cracks in concrete structure are annoying at the best of times, but if said structure is holding, say, nuclear waste, they can also be disastrous.

So a team of scientists from North Carolina State University and the University of Eastern Finland have developed plans for a “skin” that would flag up cracks or damage to the concrete’s surface. Their idea involves installing electrodes at the edges of a structure, then applying electrically conductive copper paint across the concrete. The electrodes would emit a constant, low-level current across the surface of the painted “skin”, monitored by a computer. If the surface was weakened, cracked or damaged, the paint would become less conductive, and the computer would sense a change in the signal. You can even analyse the data to produce a map of the damage.

Here’s a cracked piece of concrete, alongside a computer rendering of the damage:

Image: Aku Seppänen.

So far, the researchers have only tried the method out on small, 1m long pieces of concrete, but they’re hoping to test on bigger areas. Dr Mohammad Pour Ghaz, one of the paper’s co-authors, said the team were keen to show the method could work on “real-world structures”.

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Hector, the fatberg sniffer dog

This bloodhound, unlike Hector, is of no use in the battle against sewer blockages whatsoever. Image: Wikimedia Commons. She's called Bella, by the way.

Remember fatbergs? Those enormous monoliths of congealed kitchen waste that block sewers and ruin lives?

Luckily for the good people of the Southern Water region, there's a new top dog in town. From Sky News:

A nine-stone former police dog will be used to sniff out sewer-blocking 'fatbergs' consisting of oil, fat and grease.

Hector the bloodhound has been trained to detect blockages on Southern Water's 25,000-mile sewer network by sniffing air gaps at ground level.

The dog's nose has 1,000 times more scent receptors than a human nose - and he has previously been used to search for missing children and on-the-run criminals.

Southern Water – which serves Kent, Sussex, Hampshire and the Isle of Wight – says around 17,000 blockages are caused every year by build-ups of fat.

It's easy to be cynical about these things: to note that one dog, however talented, probably isn't going to make much difference to a sewer network which could circle the globe twice. To theorise that this entire thing is probably a PR stunt by a water provider that's really keen to remind everyone to stop pouring fat down the kitchen sink.

It's so easy to be cynical, in fact, that we’ve just done it. It's n the paragraph before this one, look.

Here’s the co-star in this unlikely buddy cop drama, handler Steve Williams:

"I've had Hector since he was eight weeks old and we worked together for Sussex Police for five years before he retired. Together we've searched for missing children and OAPs and numerous criminals on the run, but now we're fighting grime instead of crime and on the hunt for fat, oil and grease."

Hector isn't the only one to show an unlikely interest in fatbergs: remember the couple who visited one for their anniversary? Nor is the only dog to find an unlikely role in keeping the urban environment free of gross stuff. There are sniffer dogs who hunt for bed bugs, too.

God, cities are disgusting really, aren't they? We're gonna abandon this urbanism lark and find a nice little place in the country.

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