The first metamaterial superconductor: One step closer to futuristic physics-defying contraptions | ExtremeTech

In the realms of electronics, magnetism, and quantum mechanics, superconductivity has an almost mythical status. Some materials, when cooled to a critical temperature, electrical resistance instantly drops to zero and magnetic fields are completely ejected (see video below). Superconducting magnets are already used in MRI machines and particle accelerators like CERN’s LHC, and are being considered for advanced maglev trains. Zero electrical resistance means that a current can flow around a superconducting coil indefinitely (at least 100,000 years) without any applied voltage — a feature that could completely revolutionize power distribution, power storage, electric motors, computers, and more.

The problem is, the hottest superconductor yet discovered still needs to be cooled to around -140 Celsius (133 Kelvin, -220 Fahrenheit) — and cryogenic cooling just isn’t feasible for everyday use. Now, however, some US researchers may have unearthed the secret of room-temperature superconductors: Building your own metamaterial superconductor from scratch.

As we’ve covered before, metamaterials are human-made materials that have alien, not-seen-in-nature properties. The most common example is negative refraction: In nature, every known material has a positive refractive index (it always bends light a certain way) — while metamaterials can bend light in the opposite direction. These materials have led to some interesting applications, such as invisibility cloaks. Now, researchers at Towson University, the University of Maryland, and the Naval Research Laboratory have done the same thing with superconductors: They’ve tweaked a compound in the lab, metamaterial-style, to raise its critical temperature. This empirical, deliberate approach is very different from usual superconductor research, which is mostly bested on educated guesswork. [arXiv:1408.0704  "Experimental demonstration of superconducting critical temperature increase in electromagnetic metamaterials"]

Various superconductors and their critical temperatures

In theory, this is a very big step towards creating one of the most powerful, valuable, and elusive materials in the world: a room-temperature superconductor. While superconductors are already used extensively in science and medicine, the fact that they need to be kept at cryogenic (below -150C) temperatures makes them very expensive and unwieldy. A lot of work is being done into so-called “high-temperature superconductivity,” but the best anyone has managed is a critical temperature of -140C — HgBa2Ca2Cu3Ox (HBCCO) in case you were wondering.

Read our featured story: The wonderful world of wonder materials

In practice, the researchers still have a long way to go: Their metamaterial-like approach was able to raise the critical temperature of tin by 0.15 Kelvin. Still, in the realm of quantum mechanics where almost nothing is known about why or how superconductivity exists in the first place, it’s big news. We especially know very little about high-temperature superconductors – we think the “layers” of these complex compounds act like the electron equivalent of optical waveguides, steering electrons through the material with zero resistance. This new research might help us understand these high-temperature superconductors a little better, and maybe also to tweak them to move the critical temperature ever closer to room temperature.

A prototype superconducting power cable — awesome, but commercially unfeasible as it requires constant liquid nitrogen cooling.

If we can eventually master superconductors — and there’s every reason to believe that we can — then we can expect many facets of life to change very rapidly. Superconducting power lines could save billions of dollars in transmission losses — or allow for the building of world-spanning super grids. We could replace every transport system with cheap, super-fast maglev trains. It might even allow for cloaking devices… and I assure you, that’s just the beginning!

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Astronauts find living organisms clinging to the International Space Station, and aren’t sure how they got there | ExtremeTech

By James Plafke on August 22, 2014 at 1:15 pm

During a spacewalk intended to clean the International Space Station, Russian astronauts took samples from the exterior of the station for a routine analysis. The results of the experiment were quite surprising. Astronauts expected to find nothing more than contaminants created by the engines of incoming and outgoing spacecraft, but instead found that living organisms were clinging to outside of the ISS. The astronauts identified the organisms as sea plankton that likely originated from Earth, but the team couldn’t find a concrete explanation as to how these organisms made it all the way up to the space station — or how they managed to survive.

A colorized scanning electron micrograph of a tardigrade. Yes, they look amazing.

Though NASA has so far been unable to confirm whether or not the Russians truly did discover sea plankton clinging to the exterior of the station, there is some precedent for certain creatures being able to survive the vacuum of space. Tardigrades, water-dwelling microscopic invertebrates, are known to be able to survive a host of harsh environments. They can survive extreme temperatures (slightly above absolute zero to far above boiling), amounts of radiation hundreds of times higher than the lethal dose for a human, pressure around six times more than found in the deepest parts of the ocean, and the vacuum of space. The organisms found on the ISS aren’t tardigrades, but the little invertebrates show that some living organisms from Earth can indeed survive the harshness of space.

The bigger mystery is not that the plankton survived, but how they made it all the way up there, 205 miles above Earth. The scientists have already dismissed the possibility that the plankton were simply carried there on a spacecraft from Earth, as the plankton aren’t from the region where any ISS module or craft would’ve taken off. The working theory is that atmospheric currents could be scooping up the organisms then carrying them all the way to the space station, though that would mean the currents could travel an astonishing 205 miles (330 km) above the planet.

The International Space Station

Living organisms have been found far above Earth before, such as microbes and bacterial life discovered 10 and 24.8 miles, respectively, into the atmosphere — though those numbers are a far cry from 205 miles.

For now, we’ll have to wait to see if the Russian team confirms the findings with NASA. Then, maybe the two factions can work together in order to figure out how plankton made it all the way up into space, and perhaps even discover exactly why the plankton can survive. The organisms aren’t alien life, but they did pose another fascinating mystery.

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A Solar-Powered Oasis To Bring Food To Desert Cities | Co.Exist | ideas + impact

Modular greenhouses plus a very long conveyor belt could help create a new agricultural system for growing food in the desert.

Some Middle Eastern countries, like Qatar and United Arab Emirates, import more than 90% of their food. It’s a situation that is getting more expensive, and more energy-intensive, as local cities grow. Now a team of architects hopes to create a new agricultural system that could grow food in the desert–and deliver it using a solar-powered conveyor belt instead of trucks.

is a conceptual design for a modular set of prefab greenhouses, covered in solar panels, which would extend in a straight line into the desert away from a city. The passive design of the buildings would help keep out the intense heat of 120-degree summers, while the solar panels would power the rest of the building’s infrastructure and send extra energy back into the city.

Since the designers wanted to create the smallest carbon footprint possible, they chose to forgo usual transportation and create a unique conveyor system that would deliver produce without the use of any fossil fuels. The conveyor belt would be underground so it could keep running in a straight line even if buildings were in the way.

"The project aims to be flexible enough to be interrupted and keep on sending crops to the city," explains architect Javier Ponce, principal and founder of Forward Thinking Architecture, the Barcelona-based firm behind the design.

Inside the prefab greenhouses, farmers would grow crops like tomatoes, lettuce, and strawberries using a hydroponic system that can reduce fertilizers and pesticides and save 80% of the water used in traditional agriculture, in part by recycling and reusing it.

Still, it’s not clear where the water would come from; the designers suggest that groundwater could supply the farm’s needs, but many Middle Eastern countries already rely on desalination.

A small part of the recycled water would also be used to create an outdoor garden–an artificial oasis–for education. "We thought it cannot only be a farming-only building, it must have a pedagogical approach and have to be attractive in order to become a biodiversity hub which can be visited by the local people and visitors," says Ponce.

Ideally, desert populations would be small enough that the region’s sparse rainfall could support local crops. But that’s not the reality.

"The cities should be smaller, denser, and compact, but this is not the current situation for some of the Arabian peninsula cities since they have exponentially grown and attract more people and workers," says Ponce. "There has been a rapid urbanization in the area since the middle of the 20th century."

The project, he hopes, could help supply food as climate change makes the situation even more challenging. "The OAXIS project is an alternative or complementary way to respond to the food insecurity and water scarcity of the region in a self-sufficient way," Ponce says. "It aims to help reduce the food imports to feed part of the people in a nearby future based on renewable energies."

Ponce hopes to work with local governments to bring the project to life. Already, countries in the region are desperately looking for solutions; Qatar has already invested hundreds of millions in a plan to grow as much local food as possible by 2030.

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This lizard’s DNA might hold the key to regenerating human tissue

The humble green anole has but a few claims to fame: it was featured on the cover of the very first regeneration ability are 326 genes that come into play once the tail has been detached, and Arizona State University’s Dr. Kenro Kusumi thinks a better understanding of that process might ultimately lead to a way to regenerate lost or damaged human tissue.

"By following the genetic recipe for regeneration that is found in lizards, and then harnessing those same genes in human cells, it may be possible to regrow new cartilage, muscle or even spinal cord in the future," he said. Here’s one thing to keep in mind, though: Yes, this little lizard can regrow its tail, but it’s not quite the same as the original. Scientists (also from ASU, go figure) learned a few years back that the replacement tail has shorter muscle fibers than the original, to say nothing of the tube of cartilage where the vertebrae used to be. That might be a tough break for an anole recovering from a predator attack, but this breakthrough could mean we’re approaching a future where birth defects and once-debilitating injuries become temporary setbacks instead of lifelong hindrances.

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Researchers find it’s terrifyingly easy to hack traffic lights | Ars Technica

Open wireless and default passwords make controlling a city’s intersections trivial.

A typical intersection configuration.
Halderman et al., University of Michigan

Taking over a city’s intersections and making all the lights green to cause chaos is a pretty bog-standard Evil Techno Bad Guy tactic on TV and in movies, but according to a research team at the University of Michigan, doing it in real life is within the realm of anyone with a laptop and the right kind of radio. In a paper published this month, the researchers describe how they very simply and very quickly seized control of an entire system of almost 100 intersections in an unnamed Michigan city from a single ingress point.

Enlarge Nodes in the traffic light network are connected in a tree-topology IP network, all on the same subnet.
Halderman et al., University of Michigan

The exercise was conducted on actual stoplights deployed at live intersections, "with cooperation from a road agency located in Michigan." As is typical in large urban areas, the traffic lights in the subject city are networked in a tree-type topology, allowing them to pass information to and receive instruction from a central management point. The network is IP-based, with all the nodes (intersections and management computers) on a single subnet. In order to save on installation costs and increase flexibility, the traffic light system uses wireless radios rather than dedicated physical networking links for its communication infrastructure—and that’s the hole the research team exploited.

Wireless security? What’s that?

The systems in question use a combination of 5.8GHz and 900MHz radios, depending on the conditions at each intersection (two intersections with a good line-of-sight to each other use 5.8GHz because of the higher data rate, for example, while two intersections separated by obstructions would use 900MHz). The 900MHz links use "a proprietary protocol with frequency hopping spread-spectrum (FHSS)," but the 5.8GHz version of the proprietary protocol isn’t terribly different from 802.11n.

In fact, using unmodified laptops and smartphones, the team was able to see each intersection’s broadcast SSID, though they were unable to join the networks due to the protocol differences. The paper notes that researchers could have reverse-engineered the protocol to connect but instead chose to simply use the same type of custom radio for the project as the intersections use. Lest you think that’s cheating, the paper explains the decision like this:

We chose to circumvent this issue and use the same model radio that was deployed in the studied network for our attack. While these radios are not usually sold to the public, previous work has shown social engineering to be effective in obtaining radio hardware [38]….

Once the network is accessed at a single point, the attacker can send commands to any intersection on the network. This means an adversary need only attack the weakest link in the system.

The 5.8GHz network has no password and uses no encryption; with a proper radio in hand, joining is trivial.

Smash box

After gaining access, the next step was to be able to communicate with the controllers that operate each intersection. This was made easy by the fact that in this system, the control boxes run VxWorks 5.5, a version which by default gets built from source with a debug port left accessible for testing. The research team quickly discovered that the debug port was open on the live controllers and could directly "read and write arbitrary memory locations, kill tasks, and even reboot the device."

Debug access to the system also let the researchers look at how the controller communicates to its attached devices—the traffic lights and intersection cameras. They quickly discovered that the control system’s communication was totally non-obfuscated and easy to understand—and easy to subvert:

By sniffing packets sent between the controller and this program, we discovered that communication to the controller is not encrypted, requires no authentication, and is replayable. Using this information, we were then able to reverse engineer parts of the communication structure. Various command packets only differ in the last byte, allowing an attacker to easily determine remaining commands once one has been discovered. We created a program that allows a user to activate any button on the controller and then displays the results to the user. We also created a library of commands which enable scriptable attacks. We tested this code in the field and were able to access the controller remotely.

Once total access to a controller and its commands was gained, that was it—at that point, the team had full control over every intersection in the entire network. They could change lights at will and even control each intersection’s cameras. The paper lays out several potential activities that an attacker could engage in, including connecting from a moving vehicle and making all lights along the attacker’s path green, or purposefully snarling traffic to aid in the attacker’s escape after a crime.

More worrying is the ability of an attacker to engage in a type of denial-of-service attack on controlled intersections by triggering each intersection’s malfunction management unit, which would put the lights into a failure mode—like all directions blinking red—until physically reset. This would, according to the paper, let "an adversary… disable traffic lights faster than technicians can be sent to repair them."

Mitigation

The paper closes by pointing out a number of ways in which the gaping security holes could be easily closed. Chief among the recommendations is some kind of wireless security; the paper points out that the 5.8GHz systems support WPA2 encryption, and enabling it is trivial. The 900MHz systems are more secure by virtue of not using a frequency band easily accessible by consumer laptops and smartphones, but they also support the older WEP and WPA wireless encryption standards.

But a layered defense is best, and as such the paper also recommends stricter controls over the traffic systems’ IP networks—firewalling devices and strictly controlling the type of network traffic allowed.

Further, though many of the components in the network support some kind of username and password authentication scheme, the report ominously points out that "all of the devices in the deployment we studied used the default credentials that came built into the device." Doing some basic housekeeping and changing the credentials on the VxWorks intersection controllers and the wireless network components would go a long way toward frustrating attacks.

Should we panic?

It’s hard to not get a little antsy when confronted with research showing that vital pieces of public infrastructure are sitting essentially unsecured. The paper’s conclusion is clearly stated: "While traffic control systems may be built to fail into a safe state, we have shown that they are not safe from attacks by a determined adversary." There is plenty of blame to be cast, from the local agencies deploying infrastructure hardware in an unsafe state to the manufacturers helping them set things up.

In fact, the most upsetting passage in the entire paper is the dismissive response issued by the traffic controller vendor when the research team presented its findings. According to the paper, the vendor responsible stated that it "has followed the accepted industry standard and it is that standard which does not include security."

Reader comments

Lee Hutchinson / Lee is the Senior Reviews Editor at Ars and is responsible for the product news and reviews section. He also knows stuff about enterprise storage, security, and manned space flight. Lee is based in Houston, TX.

@Lee_Ars on Twitter

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Models challenge temperature reconstruction of last 12,000 years | Ars Technica

Temperature records could be skewed, or models could be missing the mark.

Ilulissat, Greenland, in the summer.
Guido Appenzeller

Climate records, like tree rings or ice cores, are invaluable archives of past climate, but they each reflect their local conditions. If you really want a global average for some time period, you’re going to have to combine many reliable records from around the world and do your math very carefully.

That’s what a group of researchers aimed to do when (as Ars covered) they used 73 records to calculate a global overview of the last 11,000 years—the warm period after the last ice age that’s called the Holocene. The Holocene temperature reconstruction showed a peak about 7,000 years ago, after which the planet slowly cooled off by a little over 0.5 degrees Celsius until that trend abruptly reversed over the last 150 years. That behavior mirrored the change in Northern Hemisphere summer sunlight driven by cycles in Earth’s orbit.

A new study published in the Proceedings of the National Academy of Sciences and led by the University of Wisconsin’s Zhengyu Liu delves into a problem with that pattern—and it’s not what climate models say should have happened.

The researchers used three different global climate models to run a series of computationally intensive simulations spanning the last 21,000 years. The simulations were responding to the orbital change in sunlight and the documented increase in greenhouse gases.

The global average temperature in the models did not peak and decline, however, unlike the Holocene temperature reconstruction. The models show that warming out of the last ice age slowed down markedly around 12,000 years ago, but still continued gradually—temperatures increased by about another 0.5 degrees Celsius before the last couple millennia. That puts the peak of the Holocene reconstruction about 1 degree Celsius higher than the temperatures in the models reach.

So, the models and reconstruction of historic temperatures don’t agree. Understanding why requires thinking about that orbital change in a little more detail. These orbital cycles don’t affect how sunlight reaches the planet uniformly. When looking at the ice age cycles, what matters is summer sunlight in the Arctic, where most of the world’s ice sheets were located and vulnerable to summer melt. Feedbacks translate the loss (or growth) of those ice sheets into global climate changes.

After they ended the most recent ice age, the orbital cycles decreased Northern Hemisphere sunlight in the summer over the course of the Holocene. Winter sunlight, conversely, saw an increase. Averaged over the whole year, the Arctic decrease was small, and the equator actually saw a slight increase.

But orbital cycles weren’t the only things changing. We also know that greenhouse gas concentrations increased a bit over the Holocene. In the climate model simulations, this overpowers the small changes in sunlight. The resulting warming causes further shrinking of the simulated ice sheets, which amplifies the warming, as the loss of reflective ice allows more sunlight to be absorbed.

The researchers say the cooling in the Holocene temperature reconstruction runs counter to what we should expect given what we know. But does this conflict arise from problems with the reconstruction or inadequacies of the models?

The researchers first point to potential issues with the temperature reconstruction. There are many different kinds of proxies for temperature, including organic compounds produced by photosynthetic plankton, ratios of elements in the shells of zooplankton, oxygen isotopes in ice cores, and identification of pollen grains. Some of these could provide recordings that are biased toward summer temperatures rather than an annual average, and the researchers believe this has had an outsized effect on the Holocene temperature reconstruction. That could exaggerate the impact of increased Arctic summer sunlight on the calculated global average temperatures.

To test this, the researchers created a virtual Holocene reconstruction by taking temperatures generated by the models from the locations where the proxy records used in the reconstruction were obtained. When summer values were used for the Arctic points rather than annual averages, the virtual reconstruction more closely resembled the real one, with a peak and decline instead of continual warming.

It didn’t look exactly like the real reconstruction, though, which left the researchers to consider what the models might be getting wrong. It’s possible that the models should be more sensitive to changing Arctic summer sunlight. Feedbacks like changes in reflectivity with snow cover or atmospheric dustiness responding to precipitation changes could be more potent than the models simulate. That would allow the summer Arctic Sun to have more influence over the rest of the planet.

Boston College’s Jeremy Shakun, one of the researchers behind the Holocene temperature reconstruction, told Ars that “any time there is a big data-model discrepancy like this, there’s a good opportunity to learn something about the world. My hunch is that both the data and models are a bit off.”

“Our [reconstruction] indeed shows the biggest cooling over the northern higher latitudes, and I have to imagine that many of the records here are biased toward summer,” Shakun said, but there are also questions about climate models. “[O]ne of the big underestimations of models with global warming so far has been that they were suggesting that summer Arctic sea ice wouldn’t fully disappear until the end of this century— whereas it has actually been slipping away much faster—so, is it possible that the models are similarly underestimating how much sea ice varied (and amplified summer [sunlight] forcing) over the Holocene?”

The new paper concludes, “If the [Holocene temperature] reconstruction is correct, it will imply major biases across the current generation of climate models. To provide a credible benchmark for future climate models, however, the proxy reconstructions will also need to be reexamined critically.”

PNAS, 2014. DOI: 10.1073/pnas.1407229111 (About DOIs).

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