Motoring with the Sims

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AMERICA’S National Highway Traffic Safety Administration (NHTSA) is investigating the fatal crash in May of a Tesla Model S electric car. Normally such an accident, tragic though it is for the friends and family of the victim, would not warrant a high-level inquiry of this sort. In the case in question, though, the car was operating on Autopilot. That is the name Tesla, an electric-vehicle-maker based in California, has chosen for its “autonomous-driving mode”, in which the vehicle itself, via sensors and computers, lifts from the person behind the wheel much of the burden of controlling the car. According to Tesla, neither the Model S’s driver nor the car’s own sensors noticed a large articulated lorry crossing the road ahead. The car therefore failed to brake, and it ended up careering under the lorry’s trailer. That ripped off its roof, killing the driver.

In the accident, which happened in Florida, the lorry, which was painted white, was set against a brightly lit sky, Tesla noted. One possibility is that the vehicle’s cameras, working in combination with its forward-facing radar, wrongly concluded that the lorry was an overhead sign with…Continue reading
Source: Economist

Flight of fancy

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LOOKING to the natural world for engineering inspiration is an idea at least as old as Leonardo da Vinci. Copying nature directly, though, has often proved hard. For example, birds flap their wings to achieve both lift and propulsion, but flying machines that imitate this action have tended not to do well. Human engineering has found it easier to create aircraft by giving them fixed, rigid wings and propelling them with motors.

Air is not the only medium through which animals move by flapping, however. Many creatures flap wings, or wing-like structures, to “fly” through water. That is something human engineers can aspire to imitate because the buoyancy of water provides free lift and its density makes propulsion easier. And, as they write in this week’s Science, a group led by Kit Parker of Harvard University have done just that. They have built a robotic stingray (pictured above) that imitates the motion of its biological counterpart. Moreover, it does so not with the electric circuits and servomotors of conventional robots, but with muscle cells engineered to mimic the elegant undulations of a living…Continue reading
Source: Economist

Autonomous cars put to the test

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Source: Economist

A new study finds that mice with genes from three parents live longer

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GENETICALLY speaking, everyone has two parents. But that could soon change. Several countries, led by Britain—whose legislators approved the idea last year—are working on a procedure called mitochondrial donation, which would result in a child with DNA from three people: its mother, its father and a female donor sometimes dubbed a mitomum.

The mitomum supplies the child’s mitochondria. These are tiny structures (one is pictured above), present in most cells, that liberate usable energy from food and oxygen. People with defective mitochondria suffer debilitating illness and often die young because the tissues of their bodies are starved of the energy they need to work. Mitochondrial diseases are hereditary, and at the moment incurable. Mitochondrial donation is designed to prevent them by replacing faulty mitochondria with healthy ones.

But mitochondria are, or used to be, creatures in their own right. They are the descendants of ancient bacteria that once lived free, but then entered into a symbiotic union with other cells. As such they have their own tiny genomes, separate from the main genome in the host cell’s nucleus. A baby…Continue reading
Source: Economist

Three’s company

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GENETICALLY speaking, everyone has two parents. But that could soon change. Several countries, led by Britain—whose legislators approved the idea last year—are working on a procedure called mitochondrial donation, which would result in a child with DNA from three people: its mother, its father and a female donor sometimes dubbed a mitomum.

The mitomum supplies the child’s mitochondria. These are tiny structures (one is pictured below), present in most cells, that liberate usable energy from food and oxygen. People with defective mitochondria suffer debilitating illness and often die young because the tissues of their bodies are starved of the energy they need to work. Mitochondrial diseases are hereditary, and at the moment incurable. Mitochondrial donation is designed to prevent them by replacing faulty mitochondria with healthy ones.

But mitochondria are, or used to be, creatures in their own right. They are the descendants of ancient bacteria that once lived free, but then entered into a symbiotic union with other cells. As such they have their own tiny genomes, separate from the main…Continue reading
Source: Economist

A probe to Jupiter has arrived successfully

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IT WAS exactly rocket science. In the early hours of Tuesday morning, cruising at a speed of around a quarter of a million kilometres an hour, some 868m km from Earth, and with Jupiter, the solar system’s biggest planet, looming in its cameras, a small space-going robot called Juno began a delicate task. This was to slam on the brakes and slow itself enough to allow it to be captured by Jupiter’s gravity.

Orbital insertions are difficult manoeuvres at the best of times. But Juno was beyond any human help. It had about half an hour to complete its job and, even at the speed of light, messages from the probe back to its masters on Earth would take longer than that to arrive. If anything went wrong it would therefore have to cope on its own.

In the end, everything went flawlessly. Back on Earth, watching humans breathed a sigh of relief: “To know we can go to bed tonight not worrying about what is going to happen tomorrow is just awesome,” said Diane Brown of NASA’s Jet Propulsion Laboratory, which built Juno.

Over the next couple of years, in a series of looping orbits designed to minimise its…Continue reading
Source: Economist

Sisyphus’s train set

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THE easiest way to squirrel electricity away in times of plenty, for use when it is scarce, is to pump water uphill with it. Such pumped storage is widely employed where local geography and hydrology permit, but it does need two basins, at different heights, to act as reservoirs, and a supply of water to fill them. At least one of the basins is likely to have to be artificial. The two must be connected by a tunnel that lets water flow between them. And the tunnel must house turbines attached to electrical devices that can do double duty—as motors to turn the turbine blades when they are pushing water from the lower reservoir to the upper one, and as generators when the blades are rotated in the opposite direction by an aqueous downrush after the upper sluices are opened.

Where geography does not favour pumped storage, though, the search is on for alternatives. These range from giant batteries, via caverns filled with compressed air, to huge flywheels made of carbon-fibre composites. But one firm looking into the matter eschews all these. It has stuck with the logic of pumped storage, which is to move…Continue reading
Source: Economist