1 Jul 2013

0 Designing a cleaner future

Bicyclean, a 2012 thesis project that helps recycle e-waste in developing nations, wins silver at Acer Incredible Green Contest
Agbogbloshie in Ghana
Agbogbloshie, Ghana. (Photo courtesy of Rachel Field.)

A slum on the outskirts of Accra, Ghana, received major media attention in 2010 and 2011 when the outside world realized where computers go to die. In an area called Agbogbloshie, impoverished residents were burning broken electronic parts, discarded and dumped by wealthier nations, to extract the metal components. Crouched around bonfires, they inhaled toxic smoke and unwittingly leached heavy metals into a nearby river, just to eke out a living.
Harvard undergraduate Rachel Field '12, an engineering sciences concentrator, read the news reports and devoted her senior thesis project to addressing the problem.
"It had gotten so much attention before, but it was amazing to me that almost nobody was trying to actually help out or figure out a solution," she recalls.
The result of her efforts is Bicyclean, a pedal-powered grindstone that pulverizes entire circuit boards inside a polycarbonate enclosure, capturing the dust. Though Field is now a year out of college, her project recently won the silver award at the Acer Foundation's Incredible Green Contest in Taiwan and was displayed for three days at COMPUTEX Taipei, one of the world's largest computer industry expositions.
The $35,000 prize will enable her to return to Ghana to test a second-generation prototype and to seek non-profit status for the endeavor, a significant milestone in a project she was afraid might fall by the wayside after graduation.
Captivated by the problem in her senior year, Field dove headfirst into her research. Supported by a grant from the Harvard Committee on African Studies, she traveled to Agbogbloshie in January 2012.
"It really does look surreal," she says. "An otherworldly place. When I first got there, it was just completely shocking and unbelievable that people would expose themselves to this hazard. But, obviously, most of the people who work there are living in these slums that are right next to it."
So she spent her month-long winter break meeting the community and observing their work.
Agbogbloshie e-waste in Ghana
The current process for breaking down electronic waste into its components involves melting it in a fire, which releases toxic fumes. (Photo courtesy of Rachel Field.)

"I knew it was very important to the project that I see what was going on first hand, and that I really talk to people," she explains. "There was a phase where I had this vision of building something like those emergency trailers that go out after big storms, but with a little chemical lab in it. Of course, once I went there, I realized that would make no sense.
"What's interesting, though, is that a lot of guys there know how to weld. There are a lot of very talented craftsmen, because they're already using these types of skills to very expertly dismantle the electronics."
A device that Ghanaians could actually assemble themselves might work well, she realized.
All undergraduates pursuing the bachelor of science degree through the School of Engineering and Applied Sciences (SEAS) are required to complete a senior design project, known as ES 100, with the guidance of an experienced adviser. Design preceptor Joe Zinter and specialist Jordan Stephens helped Field to create a rational list of goals and constraints. "I thought, well, what do I not want them to do? I don't want people to be directly exposed to toxins, and if that's one of the parameters then I don't want people to have to use heat. I want this to be something that people can afford and build from materials that are already available to them."
Bicycle parts are ubiquitous and universal, portable, relatively inexpensive, and—of course—human powered.
Bicyclean
The first prototype of the Bicyclean replaces the back wheel of a bicycle with a pedal-powered grinding wheel that pulverizes electronic waste. (Photo by Eliza Grinnell, SEAS Communications.)

Field had to learn how to weld, too, with help from Stan Cotreau, manager of thePhysics/SEAS Instructional Instrument Lab. To quickly build the first prototype, she also used a laser cutter to fabricate the polycarbonate box, and strips of fiberglass to seal it properly. And she drew on the expertise of her advisers at SEAS to create a mechanically sound design and to model it in SolidWorks.
"Jordan [Stephens] was great for the second half of the project, in terms of making the first prototype," she explains. "He basically told me, 'If you want to attach a grinding wheel to a bicycle and not have it fly off into someone's face, this is what you need to do.'"
At the competition this June, she was up against a wide range of other "green" projects—2,100 of them, in all. The high-profile judges evaluated the entries on the basis of their "earth friendliness, reality friendliness, and innovation friendliness." Teams from around the world had interpreted those parameters to produce an impressive array of solutions to sustainability challenges. The Taiwanese team that won first prize offered a new way to cool a computer without using fans and using minimal electricity; other projects tackled oil spills, reduced waste in food supply chains, and improved public transportation for suburban areas.
"If you listen to Rachel talk about her project, it always starts with, 'I traveled, I saw, I was affected, I was inspired,'" says Anas Chalah, director of the Instructional Laboratories and the Safety Program at SEAS, who has watched the project evolve over the course of two years. "It's not a trivial idea; it's a universal problem. It has the recycling element, the socioeconomic and budget element—making money out of waste—and it's environmentally friendly."
Chalah kept Field's prototype on display in the teaching labs in 2012-13 to inspire the next class of seniors as they worked on their own thesis projects, so it was still available to her when she decided to enter it in the Incredible Green Contest. Stephens helped her to polish it up again and prepare for multiple rounds of interviews; he even traveled to Taipei to support her through her final presentation.
"We don't close our doors when students graduate," remarks Chalah.
Field has spent the past year in Paris, continuing work on a project she began in the SEAS course ES 20, "How to Create Things and Have Them Matter," taught byDavid EdwardsGordon McKay Professor of the Practice of Biomedical Engineering. That project is decidedly more indulgent; Field and her collaborators have created an app that sends scents—real scents, like butterscotch or rosesfrom one user to another. Le Laboratoire, of which Edwards is founder and director, is currently hosting an exhibition—part art, part engineering—in which members of the public can sensuously experience virtual coffee using a small, handheld device called anOPHONE (for "olfactory phone") that connects to an Android phone via Bluetooth.
"This is something I've been working on all year, and having random people from the public using it is just the best feeling," says Field.
With the support she'll now receive from the Incredible Green Contest, Field may soon be able to advance the Bicyclean project to the same stage, and perhaps see it in action in Ghana. Her friends near Agbogbloshie have been sending her Facebook messages during the past year, asking when she might return. Immediately after the award ceremony, she was able to write back to them: "I just got funding."
"I didn't ever want to be someone who just stopped by for a month, saying, 'Yeah, I'll totally help you out,' and then never show up again, so this is pretty exciting," she says. "When I got to send that message to them, it was a really good moment for me. At the end of the day, the site is still there, the problem's still there, and hopefully this is going to be part of the solution."
Electronic waste in Ghana

0 Printing tiny batteries

3D printing can now be used to print lithium-ion microbatteries the size of a grain of sand
Novel application of 3D printing could enable the development of miniaturized medical implants, compact electronics, tiny robots, and more
SEM of 3D-printed battery
A research team from Harvard University and the University of Illinois at Urbana-Champaign has demonstrated the ability to 3D print a battery.  This image shows the interlaced stack of electrodes that were printed layer by layer to create the working anode and cathode of a microbattery. (SEM image courtesy of Jennifer A. Lewis.)

Cambridge, Mass. – June 18, 2013 – 3D printing can now be used to print lithium-ion microbatteries the size of a grain of sand. The printed microbatteries could supply electricity to tiny devices in fields from medicine to communications, including many that have lingered on lab benches for lack of a battery small enough to fit the device, yet provide enough stored energy to power them.
To make the microbatteries, a team based at Harvard University and the University of Illinois at Urbana-Champaign printed precisely interlaced stacks of tiny battery electrodes, each less than the width of a human hair.
“Not only did we demonstrate for the first time that we can 3D-print a battery; we demonstrated it in the most rigorous way,” said Jennifer A. Lewis, senior author of the study, who is also the Hansjörg Wyss Professor of Biologically Inspired Engineering at the Harvard School of Engineering and Applied Sciences (SEAS), and a Core Faculty Member of the Wyss Institute for Biologically Inspired Engineering at Harvard University. Lewis led the project in her prior position at the University of Illinois at Urbana-Champaign, in collaboration with co-author Shen Dillon, an Assistant Professor of Materials Science and Engineering there.
The results have been published online in the journal Advanced Materials.
In recent years engineers have invented many miniaturized devices, including medical implants, flying insect-like robots, and tiny cameras and microphones that fit on a pair of glasses. But often the batteries that power them are as large or larger than the devices themselves, which defeats the purpose of building small.
To get around this problem, manufacturers have traditionally deposited thin films of solid materials to build the electrodes. However, due to their ultra-thin design, these solid-state micro-batteries do not pack sufficient energy to power tomorrow’s miniaturized devices.
The scientists realized they could pack more energy if they could create stacks of tightly interlaced, ultrathin electrodes that were built out of plane. For this they turned to 3D printing. 3D printers follow instructions from three-dimensional computer drawings, depositing successive layers of material—inksto build a physical object from the ground up, much like stacking a deck of cards one at a time. The technique is used in a range of fields, from producing crowns in dental labs to rapid prototyping of aerospace, automotive, and consumer goods. Lewis’ group has greatly expanded the capabilities of 3D printing. They have designed a broad range of functional inksinks with useful chemical and electrical properties. And they have used those inks with their custom-built 3D printers to create precise structures with the electronic, optical, mechanical, or biologically relevant properties they want.
Diagram of 3D printed battery
To create the microbattery, a custom-built 3D printer extrudes special inks through a nozzle narrower than a human hair. Those inks solidify to create the battery’s anode (red) and cathode (purple), layer by layer. A case (green) then encloses the electrodes and the electrolyte solution is added to create a working microbattery. (Illustration courtesy of Jennifer A. Lewis.)

To print 3D electrodes, Lewis’ group first created and tested several specialized inks. Unlike the ink in an office inkjet printer, which comes out as droplets of liquid that wet the page, the inks developed for extrusion-based 3D printing must fulfill two difficult requirements. They must exit fine nozzles like toothpaste from a tube, and they must immediately harden into their final form.
In this case, the inks also had to function as electrochemically active materials to create working anodes and cathodes, and they had to harden into layers that are as narrow as those produced by thin-film manufacturing methods. To accomplish these goals, the researchers created an ink for the anode with nanoparticles of one lithium metal oxide compound, and an ink for the cathode from nanoparticles of another. The printer deposited the inks onto the teeth of two gold combs, creating a tightly interlaced stack of anodes and cathodes. Then the researchers packaged the electrodes into a tiny container and filled it with an electrolyte solution to complete the battery.
Next, they measured how much energy could be packed into the tiny batteries, how much power they could deliver, and how long they held a charge. “The electrochemical performance is comparable to commercial batteries in terms of charge and discharge rate, cycle life and energy densities. We’re just able to achieve this on a much smaller scale,” Dillon said.
“Jennifer’s innovative microbattery ink designs dramatically expand the practical uses of 3D printing, and simultaneously open up entirely new possibilities for miniaturization of all types of devices, both medical and non-medical. It’s tremendously exciting,” said Wyss Founding Director Donald Ingber, who is also a Professor of Bioengineering at Harvard SEAS.
The work was supported by the National Science Foundation and the DOE Energy Frontier Research Center on Light-Material Interactions in Energy Conversion. Lewis and Dillon collaborated with lead author Ke Sun, a graduate student in Materials Science and Engineering at the University of Illinois at Urbana-Champaign; Teng-Sing Wei, a graduate student at Harvard SEAS; Bok Yeop Ahn, a Senior Research Scientist at the Wyss Institute and SEAS; and Jung Yoon Seo, a visiting scientist in the Lewis group, from the Korea Advanced Institute of Science and Technology.
In this video, 3D printing is used to deposit a specially formulated "ink" through a fine nozzle to build a microbattery's anode layer by layer. Unlike an office inkjet printer that dispenses ink droplets onto paper, these inks are formulated to exit the nozzle like toothpaste from a tube and immediately harden into thin layers. The printed anode contains nanoparticles of a lithium metal oxide compound that provide the proper electrochemical properties.
 

Devil Dawn [ Irzzat Badut ] Copyright © 2011 - |- Template created by O Pregador - |- Powered by Blogger Templates