Category Archives: IEEE Spectrum

Biofluids Fuel Microrockets

04NWMicromotormaster-1365794310620Chemistry teachers with a flair for the dramatic sometimes throw pure sodium into a body of water, causing a reaction that blows the sodium back out of the water and blows their students’ minds. Engineer Wei Gao, at the University of California, San Diego, thinks smaller. He envisions a controlled version of that reaction so small it would fit on one side of a 20-micrometer particle.

For particles that size, ordinary water is as viscous as tar is to us (see the classic lecture “Life at Low Reynolds Number,” [PDF] by Edward Purcell). One way to push through it is to use the fluid itself as fuel. In 2011, Gao and his colleagues dropped microscopic zinc particles into hydrochloric acid. The results weren’t explosive, but the researchers clocked their zinc particles scooting at 1050 μm per second, or around 100 body lengths per second. To simulate that, a 2-meter-tall human would need to swim through four tar-filled Olympic swimming pools in 1 second.

Gao’s propulsion system is great for delivering tiny payloads to a place like the stomach, which is also very acidic, but it isn’t so useful elsewhere in the body, where conditions are more benign. Such an ability would be useful, as researchers are interested in developing microrobots that deliver medical payloads precisely to their targets (see “Magnetic Microbots to Fight Cancer,” IEEE Spectrum, October 2012). Future particle-bots could deliver drugs, perform small surgeries, or repair damaged tissue.

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Polite Robot Overlords Will Be More Persuasive

03NWRobotSavesFacesnackbot-1362426794595Baking cupcakes can be as much a matter of social interaction as it is a mechanical exercise. Never is this more true than when your kitchen partner is a robot. Their always-right, ego-deflating advice can be off-putting, reports social psychologist Sara Kiesler and her colleagues from Carnegie Mellon University, in Pittsburgh. But having them employ a different type of rhetoric could help soften the blow.

In one study, Kiesler’s former student Cristen Torrey, now at Adobe, observed how expert bakers shared advice with less-experienced volunteers. She recorded the interactions and extracted a few different approaches the experts used. For instance, “likable people equivocate when they are giving help,” Kiesler says. That is, they say things such as “Maybe you can try X” rather than simply “Do X.” They also soften their advice with extraneous words such as “Well, so, you can try X.”

So Torrey filmed a few of her own scenarios in which either robots or people shared advice with actors pretending to learn how to bake, using various combinations of the language the experts used. Then she asked a new group of volunteers to watch the videos and rate how likable, controlling, and competent the experts were. They found that equivocation, or hedging, made the experts appear more competent, less controlling, and more likable. The effect was even stronger for the robots, suggesting that people find robots less threatening than humans when the robots use humanlike language. Kiesler presented some of these results on 4 March at the ACM/IEEE International Conference on Human-Robot Interaction, in Tokyo.

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Robot to Human: ‘Trust Me’

03NewsRobot-1361308514206In a crisis control center, several teams of firefighters in Montelibretti, Italy, used laptops to guide a robotic ground vehicle into a smoke-filled highway tunnel. Inside, overturned motorcycles, errant cars, and spilled pallets impeded the robot’s progress. The rover, equipped with a video camera and autonomous navigation software, was capable of crawling through the wreckage unguided while humans monitored the video footage for accident victims. But most of the time the firefighters took manual control once the robot was a few meters into the tunnel. Continue reading Robot to Human: ‘Trust Me’

Plugging In to Plant Roots

feb13cov-300px-1359044175994Cast-off electrons in a plant’s roots can provide electricity, a Dutch team reports. Now, through a spin-off company, it hopes to grow grassy generators on rooftops and promote decentralized electrical production in wetlands in developing countries.

Plants exude a variety of waste products that microbes consume, such as glucose, acetate, butyrate, and propionate. The underground interaction leaves spare electrons in the surrounding soil and water, which researchers—led by Bert Hamelers at Wageningen University, in the Netherlands—began tapping in experiments in 2007. They were already working on using so-called microbial fuel cells (MFCs) to treat wastewater when they realized that plant roots improved the performance of the fuel cells. Continue reading Plugging In to Plant Roots