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U.S. Military Wants Laser-Armed Humvees to Shoot Down Drones

Laser weapons mounted aboard U.S. Navy ships and large trucks have already shown the power to shoot down flying drones during test trials. That early success has encouraged the U.S. military to fund a new effort to develop smaller versions of these anti-drone weapons that can fit light ground vehicles such as the military Humvee.

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Memory Cells Built on Paper

A team based at the National Taiwan University in Taipei has used a combination of inkjet and screen printing to make small resistive RAM memory cells on paper. These are the first paper-based, nonvolatile memory devices, the team says (nonvolatile means that the device saves its data even when it's powered down). 

As Andrew Steckl outlined in his feature for IEEE Spectrum last year, paper has a lot of potential as a flexible material for printed electronics. The material is less expensive than other flexible materials, such as plastic. It boasts natural wicking properties that can be used to draw fluids into sensors. And it can be easily disposed of by shredding or burning.

Basic circuit components, such as wires, resistors, capacitors, transistors and diodes, have been printed on paper. But memory is one of the last frontiers, says graduate student Der-Hsien Lien, and it will be needed if we expect paper electronics to perform computation and store data.

Lien and his colleagues tackled the problem by setting out to build resistive RAM, or RRAM, memory cells. In this memory, the cell is sandwiched between two electrodes. An applied voltage pulls ions from one of the electrodes in the cell, which lowers the cell's resistance.

Image: Der-Hsien Lien et al. An RRAM cell printed on paper. The layers, from bottom to top, consist of paper, carbon, titanium oxide, and silver.

In this case, the team constructed memory cells first using screen printing to coat paper with a layer of carbon paste that would serve as the bottom electrode. An inkjet printer was then used to print lines consisting of titanium oxide nanoparticles. After those lines had dried, they formed top electrodes by depositing small dots of silver atop the nanoparticles.

The team conducted various tests to confirm the cells could switch between states by applying a positive or negative voltage and performed reliability tests to confirm that the memory cells retained their behavior even after the paper had been bent. The results were presented last Wednesday at the Symposium on VLSI Technology in Honolulu, Hawaii. 

Lien reported memory cells as small as 50 micrometers. These could potentially be packed together to store about 1000 bits per centimeter, which amounts, Lien says, to about 1 MB on a single side of a sheet of standard A4 paper. But the team reckons better inkjet printers, which are now capable of printing submicrometer features, could increase that memory capacity to 1 GB.

The capacity could go further still by building memory cells at the intersections of crossed lines (an approach that's dubbed crossbar memory). Crossbar structures should prove easier to stack, which means that even more cells could be packed in a given area in three dimensions, says Jr-Hau He, one of the team leaders.

The team is now looking for a partner who can help build the electronics associated with storing and reading information in the memory cells.

World Cup or World's Fair? Technology Takes Center Field at the Games in Brazil

Every four years, 32 countries from around the world send their fiercest, most battle-ready soccer players to compete in the sport's most celebrated international event: the World Cup. This year, the world has sent its finest innovations as well. The shoddy arenas in Brazil may themselves be a source of shame (during the first period of yesterday's opening match between Brazil and Croatia, about half the lights in the São Paulo stadium flickered and fizzled) but the fields and stands are brimming with technology.  

Some of it is on full display. The opening kick, which is not traditionally known for being a high tech moment, took on great significance yesterday afternoon when Juliano Pinto—a Brazilian whose athletic career ended after he was paralyzed from the waist down in a 2006 car crash—stood up from his wheelchair and knocked the ball forward while wearing a robotic exoskeleton. The contraption took its commands from a set of electrodes pasted to Pinto's scalp which detected and deciphered faint electrical signals from his brain. The demonstration showcases the pioneering work of Miguel Nicolelis, a Brazilian neuroscientist and brain-computer interface researcher.

The other technologies being unveiled at the World Cup are certainly more subtle, but they actually have the potential to influence the outcome of games. During the 11th minute of yesterday's inaugural game, fans in São Paulo cringed and winced as they watched the ball deflect off the left toe of Brazilian defender Marcelo Vieira and land in the back of his own team's net, marking the first time in World Cup history that Brazil has made a goal against itself. Even before the spectators could absorb what was happening, a new automated detection system, called GoalControl, was alerting the referees on the field that a successful goal had been made. Officials in the 2014 games are wearing smart watches that vibrate whenever a ball fully crosses the goal line. The system, which uses 14 high-speed cameras (seven pointed at each goal) to capture the ball's movement in 3-D, was shown to be effective in a trial at the 2013 Confederations Cup. GoalControl successfully detected all 68 goals made at that tournament. 

And then there is all the technology that fans bring with them to the stadiums. During the 2006 World Cup, the texting, posting, and tweeting of feverish fans generated 30 gigabytes of data traffic. And that was before Instagram existed. This year, analysts are expecting a cumulative total of 12.6 terabytes.

The IEEE Standards Association has broken down all of these World Cup technologies in this comprehensive infographic:

Goings On at the North Carolina Maker Faire

Maker Faire North Carolina has been maturing. When I visited the first Maker Fair NC in 2010, there were vendors, to be sure, but it was easy enough to find average weekend tinkerers—people not associated with any company or organized group—demonstrating their techno-handiwork. That was much less true of the fifth edition, which took place last weekend at the state fairgrounds in Raleigh.

There were still many interesting things to see and do; indeed, there was a lot more than at the first gathering four years ago. This year's event included lock-picking instruction, a learn-to-solder table, and a giant battlebot arena, to name some prominent attractions. I imagine this and other Maker Faires appeal to many more people now than when they first sprung up.

Still, I couldn’t help feeling a sense of loss. Sure, the gizmos were more numerous and more polished. But they were also more predictable, dominated by things that involved robots or 3-D printing. A group conducting high-altitude balloon launches was a welcome exception. The following video should give you a sense of what I mean:

There’s no question that this was an entertaining event for the whole family. (I brought my two kids, who much enjoyed it.) But somehow it didn’t really spark any wow moments or that "I-just-have-to-build-one-of-those" feeling. I suspect the reason has something to do with the way so much of the offbeat technical tinkering of five years ago has since become almost mainstream.

The Best ROI? A CS Degree from Carnegie Mellon

Engineering and computer science are tough. And tuition at top engineering schools can cost a pretty penny. For those trying to pick a program with good return-on-investment, a recent survey of schools that produce the top-earning engineering/CS graduates could come in handy.

Computer science grads from Carnegie Mellon University make the highest reported starting salaries, averaging $89,832, according to the survey by the higher-education unit of San Francisco-based online personal finance service NerdWallet. Second and third on the list are grads of the California Institute of Technology and Stanford University’s College of Engineering, with average starting salaries of $83,750 and $74,467 respectively.

NerdWallet looked at the top 100 national universities plus the top 30 liberal arts schools from US News & World Report’s list of top colleges. It averaged starting salaries for the classes of 2011, 2012 and 2013 for each school.

As this article on Forbes points out, the survey is by no means comprehensive, since many schools, including Harvard and Yale, don’t release salary data. But it’s one of the only reports on best-paying engineering schools.

Engineers are, of course, consistently big earners (some might say overpaid) in salary reports, with no shortage of jobs. Engineering and computer science graduates fill all but one spot on the list of top 10 paid majors for the class of 2014 in the latest Salary Survey report by the National Association of Colleges and Employers. This even though starting salaries for engineers rose only 0.3% between 2013 and 2014 as opposed to 3.7% for health science majors.

Bottom line: when it comes to earning well, you can’t go wrong by choosing engineering.

Sony Creates Curved CMOS Sensors That Mimic the Eye

The retinas of humans and other animals line the curved inner surface of the eye. Now, in a bit of biomimicry, Sony engineers report that they have created a set of curved CMOS image sensors using a "bending machine" of their own construction.

The result is a simpler lens system and higher sensitivity, Kazuichiro Itonaga, a device manager with Sony's R&D Platform in Atsugi-shi, Japan reported on Tuesday at the Symposium on VLSI Technology in Honolulu, Hawaii.

A curved CMOS sensor has a few advantages over a planar sensor, Itonaga said. Because of the geometry, it can be paired with a flatter lens and a larger aperture, which lets in more light. Photodiodes at the periphery of a sensor array will be bent toward the center, which means light rays will hit them straight on instead of obliquely. What's more, the strain induced on a CMOS sensor by bending it alters the band gap of the silicon devices in the sensor region, lowering the noise created by "dark current" — the current that flows through a pixel even when it is receiving no external light. 

All told, the curved systems were 1.4 times more sensitive at the center of the sensor and twice as sensitive at the edge, according to the Sony engineers.

Itonaga gave few details on the process the team used to create the curved CMOS chips. He said that a machine was used to bend the CMOS sensors and that they were backed with a ceramic to stabilize them after bending. It was also unclear how much the chips were curved, although Itonaga said that they did achieve the same level of curvature found in the human eye.

Two chips were reported. One, which measured some 43 millimeters along the diagonal, is a full-size chip for digital cameras. The other is a smaller chip, more suitable for mobile phones, which measured 11 mm along the diagonal and boasts smaller pixels. The team integrated the curved image sensor with a lensing system and showed an image that seemed to be quite good, although it wasn't displayed alongside an image taken with an equivalent flat sensor for comparison.

This isn't the first curved image sensor to be developed. In 2008, for example, John Rogers' group at the University of Illinois at Urbana-Champaign reported they'd made a curved photodetector array by bending an array of photodiode islands connected by compressible interconnect. But Sony's work might be a bit closer to mass manufacture. The team has made somewhere in the vicinity of 100 full-size sensors with their bending machine. "We are ready," Itonaga said.

Nanotubes Capture Terahertz Radiation

A new type of detector for terahertz radiation, made from carbon nanotubes and requiring no power to operate, could usher in better airport scanners, new medical imagers, and more sensitive instruments for inspecting food and machine parts.

The detector is an array of carbon nanotubes made into a thin film 1 to 2 micrometers thick, grown on a layer of silicon. Previous attempts to use nanotubes as terahertz detectors proved difficult, because an individual nanotube had to be attached to a much larger antenna to collect the radiation. In this case, the terahertz photons are caught by a small but visible array, about 100 µm wide and roughly a millimeter long. Robert Hauge, a chemist at Rice University, in Houston, Tex., and Francois Leonard, of the Nanophotonics and Nanoelectronics Group at Sandia National Laboratory, in Livermore, Calif., and their colleagues describe the work in a recent paper in Nano Letters.

To make the array, researchers etched lines into the silicon and added iron/aluminum oxide catalysts. They then used chemical vapor deposition to grow aligned carbon nanotubes from those catalysts. The process naturally produces a mix of metallic and semiconducting nanotubes, with the overall array having an excess of positive charge. They then transferred the array onto a thermally conducting substrate—either aluminum nitride, Teflon, or a combination of the two. Next they attached gold electrodes to either end. Finally, they placed a drop of benzyl viologen onto half of the array, turning the treated nanotubes from positive to negative and creating a p-n junction.

When terahertz radiation strikes the p-n junction, it causes a photothermoelectric effect; the nanotubes heat up and cause a current to flow. The team can then measure the current to tally up the T-rays reaching the detector. Nanotubes absorb light strongly across a wide range of wavelengths, so they don’t have to apply a voltage to get a photocurrent. In fact, the scientists were able to measure light from green in the visible region to the far end of the terahertz region.

Leonard says researchers still need to integrate the detector with a source of T-rays, as well as with electronics to better measure the incoming signal. Sandia is mainly focused on security applications of terahertz radiation, he says; that frequency can penetrate most materials and return a spectrographic signature, making it easy to detect drugs and explosives, but unlike X-rays it doesn’t damage human tissue. But terahertz radiation could also be used for non-destructive testing, for instance checking the thickness of coatings on pharmaceuticals or examining the quality of paint on a machine’s embedded components.

HP's Water-Cooled Supercomputer is Designed for the Hydrophobic

Anybody who has spilled a beverage on a smart phone or laptop knows that water and computers don’t mix. But Hewlett Packard has designed a way to water-cool its servers with minimal risk of water leaking onto electrical components.

On Monday, HP introduced a supercomputer, called the Apollo 8000, which uses water-cooling to improve energy efficiency. Engineers have designed the system in a way that the active components are cooled directly by circulating water through server racks yet the water doesn’t enter into server enclosures.

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The Bike Helmet That Reads Your Brainwaves

"This is your brain on bike," said Arlene Ducao at a recent talk in New York City, showing off a map of city streets studded with colorful dots. Ducao is the inventors of MindRider, the bike helmet that reads its riders' brainwaves. The helmet also correlates the bikers' mental state with their geographical routes, creating maps of what Ducao calls the city's "psychogeography."

Sound neat? The Kickstarter campaign launched today. 

Ducao came up with the helmet idea while a student at the MIT Media Lab, and is now hoping to make it a real product. The helmet has a commercially available EEG sensor embedded in its foam, which is supposed to register the rider's mental state on a continuum of relaxed to focused concentration. A small LED light on the helmet indicates that mental state in real time (from green for relaxed to red for intense attention), and the information is also sent to the MindRider app on the user's phone.  

With the app, users can examine maps of their bike routes and potentially determine which streets are stressing them out. In the Kickstarter video below, one rider says the information gives him "insight into where we need better bike lanes." 

It remains to be seen if bike riders are eager to analyze their on-the-go neural activity. But this clever piece of hardware is part of a trend enabled by newly cheap and available brain monitoring systems. It seems likely that quantified selfers will soon have many opportunities to track not just their steps and heart rates, but also their brain patterns. 

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