The quickest way to break the ice is by submarine

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ARCTIC sea-ice is melting. For many that is a source of alarm. But for others, the ice is still not melting fast enough. They would like to give it a helping hand. Clear lanes through the Arctic ocean would permit commercial and naval shipping to travel quickly between the Atlantic and the Pacific. These lanes might also assist the search for oil and gas.

The Russian authorities seem particularly keen on the idea. Last year they launched Arktika, the first of three giant, new nuclear-powered icebreakers intended to help open such routes. But some people think this approach—bludgeoning through the ice with what is, in essence, an armour-plated knife—is old-fashioned. They believe the job could be done faster and more elegantly using a piece of physics called flexural gravity-wave resonance. If they are right, the icebreakers of tomorrow might be submarines.

Resonance icebreaking was discovered in 1974 by Canada’s coast guard, when it began using icebreaking hovercraft able to operate in waters too shallow for conventional icebreakers. At low speeds, these craft work much as icebreaking ships do, by forcing sections of pack-ice in front of…Continue reading
Source: Economist

The mesopelagic: Cinderella of the oceans

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FEW have heard of the mesopelagic. It is a layer of the ocean, a few hundred metres below the surface, where little light penetrates, so algae do not live. But it is home to animals in abundance. There are bristlemouths: finger-sized fish with gaping maws that sport arrays of needle-like teeth. They number in the quadrillions, and may be the most numerous vertebrates on Earth. There are appendicularians: free-swimming relatives of sea-squirts a few millimetres across. They build gelatinous houses several times their body-size, to filter food from the water. There are dragonfish (pictured). They have luminescent spotlamps which project beams of red light that they can see, but their prey cannot. There are even squid and swordfish—creatures at least familiar from the fishmonger’s slab.

And soon there will be nets. Having pillaged shallower waters, the world’s fishing powers are looking to the mesopelagic as a new frontier. The UN’s Food and Agriculture Organisation reported in 2002 that the fish-meal and fish-oil industries would need to exploit this part of the ocean in order to feed fish farms. In the past nine months Norway has issued 46 new licences for vessels to fish…Continue reading
Source: Economist

A 3D-printed key that can’t be copied

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KEYS have been around for a long time. The earliest, made from wood, date back 4,000 years, to the ancient Egyptians. The Romans improved them a bit by making them from metal. But there, more or less, they have stayed. Electronic card-keys aside, a key is still, basically, a piece of metal sporting a series of grooves, teeth and indentations which, when inserted into a keyway, line up to move pins and levers to lock or unlock a mechanism.

Such keys are made with conventional manufacturing techniques, such as cutting and stamping. But now there is a new way, in the form of 3D printing, to craft metal objects. And keys are about to succumb to it, to the great benefit of keyholders.

A 3D printer works by melting together layers of material that are added successively to the object being created. It can thus make something from the inside out, as it were, by printing intricate internal features and then covering them with a solid layer. Features shielded from view are extremely difficult to copy, let alone reproduce using normal machine tools. What better way to reinvent the key, reckoned Alejandro Ojeda, a mechanical engineer who…Continue reading
Source: Economist

How shoelaces come undone

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ENGINEERING brings great benefit to humanity, from aircraft to bicycles and from bridges to computer chips. It has, though, had difficulty creating a shoelace that does not accidentally come loose. At least in part, this is because no one has truly understood why shoelaces come undone in the first place. But that crucial gap in human knowledge has just been plugged. As they report in the Proceedings of the Royal Society, Christopher Daily-Diamond, Christine Gregg and Oliver O’Reilly, a group of engineers at the University of California, Berkeley, have now worked out the mechanics of shoelace-bow disintegration.

A shoelace bow is a type of slip knot that has, at its core, a reef knot. Like conventional reef knots, bows can be mistied as “granny” knots, which come undone more easily than a true reef does. But even a shoelace bow with a true reef at its core will fail eventually, and have to be retied.

Walking involves two mechanical processes, both of which might be expected to exert forces on a shoelace bow. One is the forward and back movement of the leg. The other is the impact of the shoe itself hitting the ground. Preliminary experiments carried out by Mr Daily-Diamond, Ms Gregg and Dr O’Reilly showed that neither of these alone is enough to persuade a bow to unravel. Both are needed. So they had to devise experiments…Continue reading
Source: Economist

Computer security is broken from top to bottom

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OVER a couple of days in February, hundreds of thousands of point-of-sale printers in restaurants around the world began behaving strangely. Some churned out bizarre pictures of computers and giant robots signed, “with love from the hacker God himself”. Some informed their owners that, “YOUR PRINTER HAS BEEN PWND’D”. Some told them, “For the love of God, please close this port”. When the hacker God gave an interview to Motherboard, a technology website, he claimed to be a British secondary-school pupil by the name of “Stackoverflowin”. Annoyed by the parlous state of computer security, he had, he claimed, decided to perform a public service by demonstrating just how easy it was to seize control.

Not all hackers are so public-spirited, and 2016 was a bonanza for those who are not. In February of that year cyber-crooks stole $81m directly from the central bank of Bangladesh—and would have got away with more were it not for a crucial typo. In August America’s National Security Agency (NSA) saw its own hacking tools leaked all over the internet by a group calling themselves the Shadow Brokers. (The CIA suffered a similar indignity this March.) In October a piece…Continue reading
Source: Economist