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”.

 
 
 
 

Patently obvious: Which European cities are the most inventive?

Regensburg, Germany – Pretty, inventive, and pretty inventive. Image: Wikimedia Commons.

The latest instalment of our weekly series, in which we use the Centre for Cities’ data to crunch some of the numbers on Europe’s cities.

Europe is quite a nice place. Though Nigel Farage, the Conservative Party, and anyone who’s noticed that the second syllable of Remain sounds a bit like moan will tell you otherwise, there’s some pretty nice stuff there.

The continent is host to three of the world’s richest countries in absolute terms – France, Germany, and Italy. And if you look at the top twenty countries in terms of national wealth per person – aka GDP per capita – then Europe fills more than half the spots, with twelve entries from Luxembourg in pole position to Belgium in 20th place.  Poland was one of the fastest-growing countries in the world last year. Good for you, Poland.

Croissants are tasty, Belgian beer is part of the Intangible Cultural Heritage of Humanity (apparently), and obscenely beautiful cathedrals are dotted around all over the place. In the extremely dubious language of good old-fashioned colonialism, Europe is the Old World – cultural crucible of the planet, Michelangelo, 1066 and all that.

But you probably don't think of Europe as the great 21st century hive of ingenuity, invention, and world-leading technology. Your mind might instead wander to the sprawling Californian campuses of Facebook and Google; the crammed and jostling skyscraper-shrunken streets of Hong Kong, Jakarta, and Shanghai; the ghostly-white-walled robot laboratories of Japan.

While you’re not wrong on that, you’re not necessarily right either – and looking at the numbers of patent applications to the European Patent Office will tell you that Europe remains a hub of inventive activity.

The first thing you’ll notice is that Eindhoven, in the Netherlands, is really really really inventive.

Eindhoven in Bavaria wait no that's a café the Netherlands. Image: Wikimedia Commons.

The data comes rom 2011, when there were roughly 250 patent applications per 100,000 people. That might not sound like a lot, so imagine that number differently. If you were at a very hypothetically statistically perfect school in Eindhoven with 1,000 people (discounting obvious contributory factors like post-education migration), there would be at least two people with EPO patents. Or perhaps just one very inventive person. Either way – think back to your real secondary school. How many patents have its alumni been granted? Yeah. Didn’t think so.

Eindhoven is so far out of the other cities’ league that it’s actually worth discounting it from the data to make the other figures easier to see.

Regensburg, a city with a similar population to Oxford just down the road from Nuremburg in Germany’s Bavaria, comes in second, with 83.8 applications per 100,000 people. Aachen, up near Germany’s northwestern border with the Netherlands and Belgium, follows close behind, and the prestigious university town of Heidelberg – just south of Frankfurt – narrowly takes fourth place.

This is mostly an excuse for pictures of pretty cities like Aachen. Image: Wikimedia Commons

Grenoble is the first non-Germanic entrant. The city in France’s south-east clocks 80 applications per 100,000, before the Germanic cities storm back in with Darmstadt, Zurich, and Basel in quick succession.

Grenoble, land of flying globules and mountains. Image: Wikimedia Commons.

To take a generalisation further, what’s extraordinary is that of the top 20 of these most inventive cities, only four are in countries or areas that do not speak a Germanic language. For our purposes here, I’m excluding the UK (and the English language) from that definition; Grenoble, Cambridge, Lausanne, and St Quentin en Yvelines are the only cities in the top 20 that aren’t in German, Dutch, or Swedish-speaking places.

And if you do include English as a Germanic language – which you probably should – then you’re down to Lausanne and St Quentin en Yvelines as lonely French outposts in the Germanic land of invention. Nobody wants to veer into linguistic-group stereotyping, but there’s something very Vorsprung Durch Technik going on here.

Get rid of all the Germanic-language-speaking nations included in the data (by my count: Great Britain, Germany, Germanic Switzerland, Flemish Belgium, Denmark, the Netherlands) and it’s a very different picture.

France entirely dominates, taking up the first 12 entries prior to a guest appearance from Parma in Italy. Geneva slips in behind, and the Italians romp through with Bologna, Modena, and Ferrara all in the non-Germanic top ten. Weird, huh?

And for the cruel-spirited amongst you, the least inventive cities included in the data were Almería and Jerez de la Frontera in southern Spain, Taranto, Reggio di Calabria, and Palermo in southern Italy, and Czestochowa in southern Poland. Pesky southerners.

Want more of this stuff? Follow CityMetric on Twitter or Facebook.