A Battery You Can See Through

ENERGY

Transparent batteries could lead to designs for cell phones and other gadgets.

• BY KATHERINE BOURZAC

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Researchers at Stanford University have made fully transparent batteries, the last missing component needed to make transparent displays and other electronic devices.

Stanford materials science professor Yi Cui, who led the work, says a tremendous amount of research goes into making batteries store more energy for longer, but little attention has been paid to making them "more beautiful, and fancier."

Researchers have previously made transparent variations on other major classes of electronics, including transistors and the components used to control displays, but not yet batteries. "And if you can't make the battery transparent, you can't make the gadget transparent," says Cui.

Some battery components are easier to make using transparent materials than others. The electrodes are the tricky part, says Cui. One way to make a transparent electrode is to make it very thin, on the order of about 100 nanometers thick. But a thin electrode typically can't store enough energy to be useful.

Another approach is to make the electrode in the form of a pattern that has features smaller than the naked eye can see. As long as there is enough total electrode material in the battery, this type of electrode can still store a significant amount of energy. Cui designed a mesh electrode where all the lines of the mesh are on the order of 50 micrometers, effectively invisible, and the squares inside the mesh contain no battery materials.

Fabrication is also tricky, since the usual methods for making components at this resolution require harsh chemical processes that damage battery materials. The Stanford group instead used a relatively simple method to make the transparent mesh electrodes, which are held together inside a clear, squishy polymer called PDMS.

They start by using lithography to make a mold on a silicon wafer. Then they pour liquid PDMS over the mold, cure the polymer to solidify it, and peel it off the mold. The PDMS sheet is then engraved with a grid of narrow channels. Next they drip a solution of electrode materials onto the surface of the PDMS. Capillary action pulls the materials in until they have filled all the channels to create the mesh. The researchers used standard lithium-ion battery materials to make their electrodes.

To make the complete battery, they sandwich a clear gel electrolyte between the two electrodes, and put it all inside a protective plastic wrapping. The Stanford researchers created prototypes, and used them to power an LED whose light can be seen through the battery itself.

Cui says these batteries should, in theory, be able to store about half as much energy as an equivalent-sized opaque battery, because there is a trade-off between energy density and transparency. They can lay down a thicker mesh of electrode materials to store more energy, but that means less light will get through.

So far, his lab's prototypes can store 20 watt-hours per liter, about as much energy as a nickel-cadmium battery, but Cui expects to improve this by an order of magnitude, in part by reducing the thickness of the polymer substrate, and by making the trenches that hold the electrode materials deeper.

Another way to store more energy without sacrificing transparency would be to stack multiple cells on top of one another in such a way that the grid of the electrodes lined up, allowing light to pass through. So far, the group has made electrodes that are about an inch across, but Cui says they could be made much larger, and the material could simply be cut to the desired size.

Advanced Reactor Gets Closer to Reality

Dream plant: A recent design for a nuclear reactor known as a traveling wave reactor looks similar to some conventional nuclear designs, but the way it operates is very different.
Credit: Terrapower

ENERGY

Terrapower is pushing ahead with a reactor design that uses a nearly inexhaustible fuel source.

• BY KEVIN BULLIS

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Terrapower, a startup funded in part by Nathan Myhrvold and Bill Gates, is moving closer to building a new type of nuclear reactor called a traveling wave reactor that runs on an abundant form of uranium. The company sees it as a possible alternative to fusion reactors, which are also valued for their potential to produce power from a nearly inexhaustible source of fuel.

Work on Terrapower's reactor design began in 2006. Since then, the company has changed its original design to make the reactor look more like a conventional one. The changes would make the reactor easier to engineer and build. The company has also calculated precise dimensions and performance parameters for the reactor. Terrapower expects to begin construction of a 100-megawatt demonstration plant in 2016 and start it up in 2020. It's working with a consortium of national labs, universities, and corporations to overcome the primary technical challenge of the new reactor: developing new materials that can withstand use in the reactor core for decades at a time. It has yet to secure a site for an experimental plant—or the funding to build it.

The reactor is designed to be safer than conventional nuclear reactors because it doesn't require electricity to run cooling systems to prevent a meltdown. But the new reactor doesn't solve what is probably the biggest problem facing nuclear power today: the high cost of building them. John Gilleland, Terrapower's CEO, says the company expects the reactors to cost about as much to build as conventional ones, "but the jury is still not in on that."

Conventional reactors generate heat and electricity as a result of the fission of a rare form of uranium—uranium 235. In a traveling wave reactor, a small amount of uranium 235 is used to start up the reactor. The neutrons the reactor produces then convert the far more abundant uranium 238 into plutonium 239, a fissile material that can generate the heat needed for nuclear power. Uranium 238 is readily available in part because it's a waste product of the enrichment processes used to make conventional nuclear fuel. It may also be affordable in the future to extract uranium 238 from seawater if demand for nuclear fuel is high. Terrapower says there's enough of this fuel to supply the world with power for a million years, even if everyone were to use as much power as people in the United States do.

In the original Terrapower design, the reactor core was filled with a large collection of uranium 238. The process of converting it starts at one end, producing plutonium that's immediately split to generate heat and convert more uranium to plutonium. The reaction moves from one end to the other—in a "traveling wave"—until no more reactions can occur.

In the new design, the reactions all take place near the reactor's center instead of starting at one end and moving to the other. To start, uranium 235 fuel rods are arranged in the center of the reactor. Surrounding these rods are ones made up of uranium 238. As the nuclear reactions proceed, the uranium 238 rods closest to the core are the first to be converted into plutonium, which is then used up in fission reactions that produce yet more plutonium in nearby fuel rods. As the innermost fuel rods are used up, they're taken out of the center using a remote-controlled mechanical device and moved to the periphery of the reactor. The remaining uranium 238 rods—including those that were close enough to the center that some of the uranium has been converted to plutonium—are then shuffled toward the center to take the place of the spent fuel.

Phone App Could Keep an Eye on Your Ride

Remote control: An Intel researcher demonstrates a way to securely link a phone app to a particular vehicle.
Credit: Intel

COMPUTING

Intel is testing technology that would issue an alert if someone hit your parked car, and could capture video if a thief made off with it.

• BY TOM SIMONITE

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When Victor Lortz's phone buzzes, it may not be just an e-mail or text message. He gets updates from his car, too. Anytime something hits or shakes his parked Infiniti sedan with significant enough force, an app on his smart phone lets him know, and streams live video from the vehicle.

Lortz is a senior research scientist at chipmaker Intel's research labs in Santa Clara, California. He's working on a project that connects the electronics inside a car to the Internet, so that mobile apps can provide a car owner with updates on his vehicle when the two are apart.

The system developed by Lortz and colleagues at Intel involves installing a custom circuit board with Atom mobile processors (the type used in some notebook computers). That board interfaces with the car's electronics, and connects the car to a cloud server over a mobile network.

Intel researchers have developed apps for Android and Apple phones to make use of this new connectivity; they can access data from the car and also send commands to it. The apps can be used for simple things, for example, opening the car door or starting the vehicle, as well as for more sophisticated tasks, like sending an alert and streaming video when the car's motion sensors or alarm are triggered. The owner can view the live feed immediately, but the video is also archived in the cloud so it can be viewed later.

"The idea of being notified when something happens to your car has a lot of appeal," says Lortz. "It's something that's just not possible today."

Intel is also considering how a car with the system could share data on the car's performance with the manufacturer. A person's driving behavior could also, conceivably, be shared with insurers or local transportation authorities. "We're looking at how you could collect that without compromising the privacy of the driver," says Lortz.

In the past year, many car manufacturers, including BMW, Ford, and Toyota, have made it possible for a car to make use of a smart phone's Internet connection, enabling the car to use Web radio services like Pandora. But no carmaker has yet developed a security app like Intel's.

Dominique Bonte, an analyst who specializes in connected-car technology at ABI Research, says Intel's approach is promising. If it finds favor with multiple manufacturers, it would be easier for software developers to write applications that could be used on many different vehicles, just as different Android phone models can use the same apps. However, he notes, drivers shouldn't count on their car always being able to contact them. "There are big gaps in mobile coverage across the U.S., especially the high-bandwidth coverage needed for video," he says.

A recent survey by ABI showed that safety and security features were the most popular connected-car technologies among consumers, suggesting that Intel might be on to something with its proof-of-concept security app. But Bonte thinks that, as car manufacturers make it easier to build apps for their vehicles, less serious apps will also take off. "We found entertainment to be the fastest growing category," he says. He predicts that the market for in-car apps will mimic the market for phone apps, and will be similarly dominated by music and games.

One big challenge for such technology is that driver attention is constrained, says Bonte. "Car manufacturers are investing a lot in speech technology and are also starting to look at ideas like heads-up displays [which layer information onto the windshield] and gesture recognition," he says. Such technologies could potentially address the driver attention problem.

Lortz says finding ways to introduce computer interfaces into cars, where they haven't traditionally appeared, is something Intel's researchers are focusing on. One example is their attempt to make it easy for drivers to securely link an app with a vehicle. Lortz and his colleagues' solution is to have a car display a bar code on its dashboard. When a smart phone reads the code, it is instructed to download the app and authenticate with that vehicle only. Phones with short-range wireless data transfer technology—like that used by Google Wallet—can do the same when tapped on a car's dashboad.

How Design Software Will Shape Manufacturing's Future

3-D printing: A 3-D printer squirted out each of the 200 plastic parts in this 10-foot-long turbo-prop engine, demonstrating a technology that could soon be used for more than just prototyping.
Credit: Autodesk

BUSINESS

Powerful design tools and techniques such as 3-D printing enable manufacturers to be more nimble, says Autodesk's manufacturing boss.

• BY TOM SIMONITE

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Autodesk, a multinational software company based in San Rafael, California, makes 3-D design software used by everyone from automotive manufacturing giants to Hollywood studios. Now it is betting that those digital tools will have an increasingly powerful role in what happens on factory floors, enabling manufacturers to embrace more flexible strategies that deliver more customized products.

Buzz Kross, who heads the company's manufacturing industry group, says the manufacturers he works with see an opportunity in new technology at a time when they sense that the boom in outsourcing to China has run its course. "There have always been companies that differentiate based on their ability to manufacture most efficiently, and others based on design and invention—it's the difference between GM and Tesla," says Kross. "Now a lot of manufacturers are leaning more to the design model."

Kross says that rising costs in China's maturing economy and high-profile problems with out-sourced  components, like those that plagued Boeing's 787, are making the model of high-volume, low-cost outsourced production less economically attractive. The result is that a wider range of companies are considering adopting a more flexible, premium approach to manufacturing that has previously been limited to a relatively small niche. Kross is trying to help that trend along with software such as Inventor, which provides a way to digitally prototype and test mechanical designs, and Streamline, which enables engineers, designers, and managers to collaborate on a design. Both are intended to speed the journey from digital drawing board to factory floor.

"You don't need to center everything on making millions of the same thing at the absolute cheapest price anymore," says Kross. He cites the growing popularity of a model known as ETO (engineer to order), in which businesses buying from manufacturers order by referring to a list of general rules, not a catalogue and price list. For each order, a manufacturer makes and assembles a product very specific to the customer's needs. That approach also cuts costs, because raw materials and parts don't have to be held in stock; rather, they can be purchased to match the latest order. And the customized products can command a higher price than a conventionally made one, Kross says: "These companies capture a larger share of the customer's wallet this way."

That style of manufacturing makes the design process—and design software—much more central. Kross says that 3-D printingtechnology will blur the line between design and manufacturing still further.

"Everybody's already embracing it for prototyping," says Kross. "You can already print moving components and subassemblies that don't need any assembly. That's incredibly useful, whether you make pumps or power trains or chairs." Nike, an Autodesk customer, prototypes shoes by using a printer to squirt out materials that have more or less compressibility, depending on how bouncy and flexible each part of the sole is meant to be.

The next step is for 3-D printing to become a manufacturing method rather than solely a prototyping tool, says Kross. Small companies are already trying this, but it won't be long before large manufacturers follow suit. "Think about when you buy a Dell computer and they let you choose all the different components," Kroll says. "3-D printing for manufacturing will allow you to have that, but with nearly infinite options."

This process may cost manufacturers more than production at a more conventional or offshore factory. But as with the ETO approach, more customized products fetch higher prices, says Kroll. Jewelry, furniture, and consumer electronics are all areas that could benefit from the new techniques, he says. "People don't like it when they have the same thing as everything else and will pay more to get exactly what they choose."

COMPUTING

New Language for Programming in Parallel

Writing code for the latest multicore chips is notoriously tricky, but a new language could make it simpler, and make computers more efficient in the process.

• BY DUNCAN GRAHAM-ROWE

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A new programming language has been designed to get the most out of the latest multicore computer processors. If it finds favor among coders, it could provide more powerful software for many computers.

Over the last few years, as they've run up against the physical limits of miniaturization, microchip makers have shifted from increasing the power of processor cores—the part of a chip that handles data and instructions—to adding more cores to a single chip. For example, Intel's i3 and i7 processors have two and four cores, respectively.

This presents a challenge for programmers. Since most programming languages were designed for single-core chips, it can be tricky to divide tasks up and send them to each core in parallel. If a coder isn't careful, this can cause errors in the way that each core in the chip accesses the shared sections of memory.

Tucker Taft, the chief technology officer and chairman of the Boston-based software companySofCheck, designed the new language—called Parallel Specification and Implementation Language (ParaSail)—specifically for writing software for multicore processors. The language is intended to avoid the pitfalls that typically happen when working with multicore chips.

To a programmer, ParaSail looks like a modified form of C or C++, two leading languages. The difference is that it automatically splits a program into thousands of smaller tasks that can then be spread across cores—a trick called pico-threading, which maximizes the number of tasks being carried out in parallel, regardless of the number of cores. ParaSail also does the debugging automatically, which makes code safer. "Everything is done in parallel by default, unless you tell it otherwise," Taft says.

Over the next decade, the number of cores on computer chips is expected to increase even further. "There are some machines out there with dozens or hundreds of cores now," says Taft.

ParaSail uses a number of other tricks, some that draw on languages developed in the late 1980s and early 1990s for supercomputers—machines running many individual computer chips networked together. "The design of the language itself is essentially complete," says Taft, who presented details of the language on Wednesday at the O'Reilly Open Source Convention. "The first version of the compiler will be released in the next month or so." The language will work on Windows, Mac, and Linux computers.

Microsoft and Intel are putting $20 million into adapting existing languages for multicore processors, so it's difficult to say if ParaSail will become widely adopted. "There are a lot of people chipping away at the problem, taking existing languages and trying to make them better at handling parallel processing," says Taft.

Taft already has a proven track record in the world of computer language development, saysDenis Nicole of the Dependable Systems and Software Engineering Group at Southampton University. But he adds that "it usually takes companies the size of Sun to push new languages on the community."