Fall 2012 Magazine

The Data Age

Stories From the Intersection

Energy and environment • Health and wellness • Materials • Systems • Creating leaders


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Energy and Environment

Investment Tax Credit Recommended to Spur Wind Power
Wind farm

The State of Illinois is facing an important renewable energy deadline in 2025. Harold H. Kung, professor of chemical and biological engineering, has advice for state officials to consider now: investment tax credit.

Illinois is obligated to begin increasing its production of electricity from renewable sources, a significant chunk of which will be wind power. Wind farms are expensive to build, resulting in higher energy costs for consumers and some risk to the investors needed to stimulate wind farm development. Government tax incentives can help address these issues.

Kung analyzed the impact of two incentives—investment tax credit and production tax credit—in six wind farm scenarios and found the former to be more attractive for both consumers and investors. It would provide a lower cost to consumers for electricity produced from wind and a faster return on investment for investors. Kung added, however, that the benefit of investment tax credit disappears when the capital cost is fully depreciated, whereas a production tax credit could continue for as long as the policy permits.

Health and Wellness

Biocompatible Electronics Vanish When No Longer Needed
Dissolving electronics

A team of researchers from Northwestern University, the University of Illinois at Urbana-Champaign, and Tufts University has demonstrated biocompatible “transient” electronics that gradually disappear on a specified schedule.

“This is a completely new concept,”
said Yonggang Huang, Joseph Cummings Professor of Civil and Environmental Engineering and Mech­anical Engineering, who led the Northwestern research team.

The novel technology opens up the possibility of medical devices implanted inside the human body to monitor functions such as brain activity or to deliver drugs. When no longer needed, the electronics would be fully absorbed by the body with no adverse effects.

The system is made up of the elec­tronics encapsulated by layers composed of magnesium oxide covered with silk. The encapsulation layers dissolve first and dictate the first dissolution timescale; the magnesium electrodes in the electronics define the second timescale.

John Rogers, of the University of Illinois, led the combined multidisciplinary research team and the U. of I. group that worked on the experimental and fabrication work of the transient electronics.
Huang and his Northwestern team developed a model that can accurately predict how thick the encapsulation layers need to be for a specific dissolution time. The model was tested against experimental evidence, and the two agreed each time.

The researchers demonstrated that the transient electronics, including heater, sensor, and power supply, can operate in both water and a phosphate-buffered saline liquid. (PBS is chemically very similar to fluids in the human body.) Induction coils provide a wireless power supply to the electronics. “This way the devices in water or PBS liquid can have power without being physically connected to a power source,” Huang said.

The research was published in Septem­ber in the journal Science.


New Crystals Could Cut Cloud Computing Cost
Crystalline materials could mean new future for memory applications

A new class of organic materials developed at Northwestern boasts ferroelectric properties that might be used to bring down the cost of cloud computing. The crystalline materials also have a great memory and are simple and inexpensive, enhancing their attractiveness for computer and cellphone memory applications.

A team of Northwestern organic chemists discovered that they could create long crystals with just two small organic molecules whose strong attraction causes them to self-assemble into an ordered network, which is needed for ferroelectricity. Ferroelectric materials exhibit spontaneous electric polarization (one side of the material is positive and the opposite side negative) that can be reversed by the application of an electric field (from a battery, for example). These two possible orientations make the materials attractive to computer memory researchers because computer memory stores information in ones and zeros, and one orientation could correspond to a one and the other to a zero.

Currently, cloud computing is expensive because electric power has to be kept on to retain information. The new ferroelectric materials could be developed with nonvolatile memory to retain information when power is turned off. If the cloud and electronic devices were to operate on nonvolatile memory, $6 billion in electricity costs would be saved in the United States annually.

 “This work will serve as a guide for designing these materials and using ferroelectricity in new ways,” said Samuel I. Stupp, Board of Trustees Professor of Chemistry, Materials Science and Engineering, and Medicine and member of the research team. The results were published in Nature in August.

Creating Leaders

McCormick Students Honored at Conference
Joshua Lawrence (second from left) and Jovanca Smith (second from right)

Two McCormick graduate students received honors in August at the National GEM Con­sortium conference, which promotes the participation of underrepresented groups in postgraduate science and engineering education. Northwestern was the only school with two finalists among the six in the technical presentations.

Joshua Lawrence (second from left), a master’s student in electrical engineering and computer science, was named GEM fellow of the year, the top prize among nearly 100 GEM fellows. Lawrence also won first prize in the MS division for his technical presentation.

Jovanca Smith (second from right), a PhD student in civil and environmental engineering, won second place in the PhD Division for her technical presentation.

GEM fellows are offered stipends, paid tuition, and internships with GEM employers. The annual conference is an opportunity for these fellows to network and present their internship research to the GEM membership.


Complex Networks Have Similar Skeletons

Northwestern researchers have discovered that very different complex networks—ranging from global air traffic to neural networks—share very similar backbones. By stripping each network down to its essential nodes and links, they have found that each network possesses a skeleton and that these skeletons share common features, much like vertebrates do.

The surprising dis­covery that net­works all have skeletons and that they are similar was published by the journal Nature Communications. The researchers studied a variety of bio­­­logical, technological, and social networks and found that all of them have evolved according to basic growth mechanisms. The findings could be particularly useful in understanding how anything—a disease, a rumor, or information—spreads across a network.

“Infectious diseases such as H1N1 and SARS spread in a similar way, and it turns out [each] network’s skeleton played an important role in shaping the global spread,” said Dirk Brockmann, associate professor of engineering sciences and applied mathematics. “Now, with this new understanding and by looking at the skeleton, we should be able to use this knowledge in the future to predict how a new outbreak might spread.”  (For more, see “Models in the fight against disease".)