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Haiti update: Georgia Tech humanitarian logistics and civil engineering/cements experts launch new effort to assess & reduce earthquake risks
Seismic and plate tectonic setting of the Caribbean region. Credit: Eric Calais, Purdue Univ.
Back in early January, I had a story about proposal from a Georgia Tech team of cements experts who had a remarkable pragmatic and inexpensive proposal for rebuilding Haiti: Recycle the concrete that is laying around in huge rubble mounds. (Their idea wasn’t to recycle it willy-nilly; instead they had proposed and tested some simple approaches using low-tech available tools and equipment to convert refuse into usable aggregate plus add some abundant local sands, which, together, could produce strong construction-grade concrete.)
I learned from one of the GT team members that the leader of the research effort, Reginald DesRoches, has recently secured funding from the non-profit Speedwell Foundation to support a new project, “Reducing seismic risks for developing countries in the Caribbean.”
Kim Kurtis tells me DesRoches’ goal is to assess whether “another Haiti” could occur. Kurtis, who like DesRoches is a member of the faculty at GT’s School of Civil and Environmental Engineering, says they already know there is a strong correlation among a country’s per capita GDP, fatalities sustained during an earthquake and overall economic losses. She says experience has demonstrated that countries with a lower GDP (e.g., Haiti, Indonesia) fare more poorly in the event of an earthquake than countries with higher GDPs.
In the Caribbean region, Kurtis notes, faults run not only through Haiti, but other populous islands, such as Jamaica. DesRoches’ initiative came about because, unfortunately, little has been done to assess these countries’ vulnerability in the event of an earthquake.
Kurtis, who again will be working with DesRoches, says the first year of research will involve touring the region and collecting data to better understand existing vulnerabilities (documenting hazards, construction quality, levels of preparedness, etc.). Phase I will culminate with a workshop, which is envisioned to include government officials, emergency managers, engineers and scientists—from the Caribbean and the United States—to discuss the findings.
Others involved in this project are Glenn Rix (also in GT’s School of CEE) plus three the university’s School of Industrial & Systems Engineering (ISyE): Ozlem Ergun, Pinar Keskinocak and Julie Swann.
Kurtis says the CEE members bring expertise in seismology, multi-hazard assessment,
structural behavior/design, cement-based materials and sustainability; the ISyE team brings expertise in humanitarian logistics (Ergun, Keskinocak and Swann also codirect Georgia Tech’s Center for Health and Humanitarian Logistics).
After Phase 1, it is likely that the group will turn its attention to converting their findings to practical solutions, such as enhancing building codes to improve seismic resistance in new construction, coordinating retrofit of existing structures using methods appropriate for the region and working with NGOs on both earthquake preparedness and short- and long-term responses.
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Get flexible: Georgia Tech group shows how to ‘draw’ nano-sized ferroelectric structures on plastic substrates
Georgia Tech researchers display samples of materials on which ferroelectric nanostructures have been fabricated by thermochemical nanolithography. Graduate research assistant Yaser Bastani (left) with silicon, assistant professor Nazanin Bassiri-Gharb with polyimide and postdoctoral fellow Suenne Kim with glass. (Credit: Gary Meek, Georgia Tech.)
“We can directly create piezoelectric materials of the shape we want, where we want them, on flexible substrates,” says Nazanin Bassiri-Gharb in a Georgia Tech press release. ”This is the first time that structures like these have been directly grown with a CMOS-compatible process at such a small resolution. Not only have we been able to grow these ferroelectric structures at low substrate temperatures, but we have also been able to pattern them at very small scales.”
Bassiri-Gharb, a mechanical engineering assistant professor at the Georgia Institute of Technology, and others at the school have been learning how to successfully use thermochemical nanolithography to make nanometer-scale ferroelectric structures directly on bendable plastic substrates. From an applications viewpoint, this means manufacturers can now use TCNL on a substrate that would typically be ruled out because it would be unable to withstand normal processing temperatures.
The TCNL efforts are described in recent paper in Advanced Materials (doi:10.1002/adma.201101991).
TCNL, itself, isn’t novel and apparently was developed around 2007 at Georgia Tech. In general, it involves the use of a heated atomic force microscope tip to produce patterns. Since then, investigators have been perfecting where its use might be most beneficial. Because the polarization of ferroelectrics can easily be toggled they are of interest for random access memory elements.
In this new paper, investigators report they have produced wires approximately 30 nanometers wide and spheres with diameters of approximately 10 nanometers using the patterning technique. According to Suenne Kim, the paper’s first author and a postdoctoral fellow in GT’s School of Physics, ”Spheres with potential application as ferroelectric memory were fabricated at densities exceeding 200 gigabytes per square inch, currently the record for this perovskite-type ferroelectric material.”
According to a GT news release, the group hopes their work demonstrates how TCNL could lead to high-density, low-cost production of complex ferroelectric structures. The types of applications they have in mind are energy-harvesting arrays, sensors and actuators in nanoelectromechanical systems and microelectromechanical systems.
Image shows the topography (by atomic force microscope) of a ferroelectric PTO line array crystallized on a 360-nanometer thick precursor film on polyimide. Bar corresponds to one micron. (Credit: Suenne Kim, Georgia Tech.)
The problem is that normal ferroelectric crystallization processes require temperatures that exceed 600°C. Typically, ferroelectric structures first had to be grown on a single-crystal substrate and then transferred to a flexible substrate for use in energy-harvesting. But, by using an AFM tip on amophous precursor materials, TCNL leads to only “extremely localized heating” that is more on the order of 250°C, Then, it’s only a matter of matter of using computer controls to draw patterns of crystallized material, for example, lines of ferroelectric nanowires drawn along the direction in which strain would be applied.
The GT group says it has created lead titanate and lead zirconate titanate structures on polyimide, glass and silicon substrates. In general, however, the researchers say the only substrate requirement is that it be able to withstand the 250” heating step.
Next, the group says it plans on assembling arrays of AFM tips to produce larger patterned areas, and also get a handle on the growth thermodynamics of ferroelectric materials at the nanoscale.
Pztlines-sem: Scanning electron microscope image shows a large PZT line array crystallized on a 240-nanometer thick precursor film on a platinized silicon wafer. (Credit: Yaser Bastani, Georgia Tech.)
“We are really addressing the problem caused by the existing limitations of photolithography at these size scales,” says GT physics professor Elisa Riedo, in the news release. “We can envision creating a full device based on the same fabrication technique without the requirements of costly clean rooms and vacuum-based equipment. We are moving toward a process in which multiple steps are done using the same tool to pattern at the small scale.”
The research was sponsored by NSF and the DOE, and also involved scientists from the University of Illinois Urbana-Champaign and the University of Nebraska Lincoln.
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White House invests $500M in Advanced Manufacturing Partnership
President Barack Obama announces Advanced Manufacturing Initiative at Carnegie Mellon University. Credit: Pete Souza; Official White House Photo.
Last week President Obama unveiled a new initiative to invest in emerging technologies and create new manufacturing jobs and increase the nation’s global competitiveness. During a visit to Carnegie Mellon University in Pittsburgh, Pa., Obama introduced the Advanced Manufacturing Partnership, which, according to the White House press release, will invest more than $500 million to leverage existing programs and proposals to meet these goals.
The press release said that AMP’s initial investments will target manufacturing for critical national security industries, advanced materials development, robotics, improving energy efficiency of manufacturing processes and accelerating the product development timeline for manufactured goods.
“Today, I’m calling for all of us to come together- private sector industry, universities, and the government- to spark a renaissance in American manufacturing and help our manufacturers develop the cutting-edge tools they need to compete with anyone in the world,” said Obama in the press release. “With these key investments, we can ensure that the United States remains a nation that ‘invents it here and manufactures it here’ and creates high-quality, good paying jobs for American workers.”
AMP is a response to the first of four recommendations made by the President’s Council of Advisors on Science and Technology in their just-released report, “Ensuring Leadership in Advanced Manufacturing (pdf).” The report cites an erosion of domestic leadership in manufacturing and the heavy investment of other nations to fill that void, the advantages of having R&D and manufacturing located in the United States, the essential role of an advanced manufacturing competence in national security and that, historically, federal investment in new technologies has cleared the way for fledglings to become major new industries.
The PCAST report concludes that individual companies cannot go it alone: “Private investment must be complemented by public investment to overcome market failures. Key opportunities include investing in the advancement of new technologies with transformative potential, supporting shared infrastructure, and accelerating the manufacturing process through targeted support for new methods and approaches.”
To create an environment conducive to innovation and to overcome market failures, the PCAST report recommended a four-point plan:
- Launch an advanced manufacturing initiative;
- Improve tax policy;
- Support research; and
- Strengthen the workforce.
AMP is the administration’s response to the first of these, and as recommended by PCAST, is a government, industry and academic partnership. It will be led by Andrew Liveris, CEO of Dow Chemical and Susan Hockfield, president of MIT, and will work closely with the White House’s National Economic Council, Office of Science and Technology Policy, as well as with PCAST.
The first team has been picked already. From industry it will be Allegheny Technologies, Caterpillar, Corning, Dow Chemical, Ford, Honeywell, Intel, Johnson & Johnson, Northrop Grumman, Proctor & Gamble and Stryker. Participating universities are MIT, Carnegie Mellon, Georgia Tech, Stanford, UC-Berkeley and University of Michigan. Government players are DARPA, DOE, DOD, and the Commerce Department.
The White House press release gives examples of how several partnerships that are in place will modify their programs to support AMP goals. Several of the named agencies have a long history as important, strategic investors in materials science and engineering such as NSF, NASA and NIST. For example, NIST, a Commerce Department agency, issued a press release outlining its programs that will support the AMP initiative including robotics, nanomanufacturing, advanced materials design through the Materials Genome Initiative and an advanced manufacturing technology consortium scheduled for launch in FY2010.
The PCAST report recommended that AMP funding should rise from $500 million to $1 billion over the course of four years. While touring Carnegie Mellon and seeing demonstrations of several cutting-edge technologies developed at the university, Obama said that it was important for ideas to have a place to incubate and become products that can be made in the US and sold worldwide. “And that’s in our blood. That’s who we are. We are inventors, and we are makers, and we are doers.”
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New barium oxide/nickel interface demonstrated for self-cleaning, lower temp SOFC anode
Regents professor Meilin Liu (right) and postdoctoral researcher Mingfei Liu examine a button fuel cell used to evaluate a new self-cleaning anode material based on barium oxide. The self-cleaning technique could allow fuel cells to be powered by coal gas. Credit: Georgia Tech Photo, Gary Meek.
The nation’s energy spotlight has drifted away from solid oxide fuel cells over the last year or so (the last big splash being the Bloom Energy media fest), but that doesn’t mean researchers aren’t still working to figure out how to overcome the barriers to making SOFCs commercially successful.
One of the main engineering barriers is operating temperature. The problem is that when SOFCs operate above 850 °C, the materials or other workarounds that have to be used to prevent performance problems are either expensive or require fuel dilution. Either way, they make these fuel cells cost prohibitive under current circumstances. Go below 850 °C and coking (carbon buildup) on traditional anode materials, such as Ni-yttrium-stabilized zirconia, causes deactivation and creates sharp drop offs in fuel-to-energy conversion. It’s a pity because these fuel cells could be fueled with waste hydrocarbon sources, such as municipal wastes and biomass, or could double the energy output of coal (gasified) and consequently cut CO2 emissions in half.
But, a workgroup led by ACerS member Meilin Liu believes it has found a new way to make an SOFC anode, which can operate effectively and efficiently with carbonaceous fuels at 750 °C, using a nanostructured barium oxide/nickel interface. A paper about the group’s achievements was recently published in Nature Communications (doi:10:1038/ncomms1359). Liu, professor of MSE at Georgia Tech, and his research group collaborated with researchers at the Brookhaven National Lab, the New Jersey Institute of Technology and Oak Ridge National Lab.
The BaO possibilities were interesting to the group because the oxide is known to have been used as a promoter for reforming catalysts (the catalysts that breakdown hydrocarbon fuels into hydrogen and a byproduct). The challenge was to come up with a way of using the material that would not create a block to electrons but absorb water that would be used to remove carbon and combat coking. Their solution was to deposit (by evaporation) BaO onto Ni-YST. According to the authors, “In this process, BaO reacts with the surfaces of NiO, producing a thin film of NiO-BaO compounds on the NiO surface. On exposure to fuel, the thin film of NiO–BaO compounds is reduced to nanosized islands distributed on the Ni surface.”
Button-type test cells were made with the new anode structures. When fueled with dry C3H8, the cells attained a power density of ~0.88 Wcm-2 at 750 °C (more than 50 percent higher that traditional SOFCs operated under the same conditions). Further, cells were able to produce a stable current of 500 mA cm-2 for 100 hours, indicating the absence of coking.
Researchers also tested the new cells tolerance to CO. They used a wet (~3 v%) CO fuel stream and attained a power density of ~0.70 Wcm-2 (again, higher than what has been reported for other SOFC under the same conditions).
Finally, they used a fluidized carbon bed–SOFC arrangement to test the anode’s possible performance with something like gasified coal. They formed the fuel stream using a wet CO2 gasification technique. Here, they attained a peak power density of ~1.08 Wcm-2 at 850 °C, twice that of other SOFCs. When they lowered the temperature to 750 °C, the cell peak power density was still remarkable: ~0.65 Wcm-2 . Although cells cannot operate for long at this lower temperature, the the new anode delivered stable performance for 1000 hours.
The researchers say the performance and resistance to coking demonstrated using BaO/Ni interface “represent a vital step towards a cost-effecitve fuel cell for direct conversion of hydrocarbons and gasified carbonaceous solid fuels to electricity.”
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Video of the week: Z.L. Wang on piezoeletronics and piezophotoeletronics
Georgia Tech’s Zhong-Lin Wang was a plenary speaker at the recent 35th International Conference on Advanced Ceramics and Composites. There, I was able to catch up to him and ask him about his efforts in a field he calls piezoelectronics. Wang has been researching the use of zinc-oxide piezoelectric materials in semiconductor applications, where the piezo material serves as the gate between the p- and n- regions in complementary metal-oxide semiconductor technology. In brief, the strain on the piezo material can alter the charge transport between the p- and n-interfaces, which can be used to turn off (or turn on) the switch. This opens new opportunities for logic operations. He discusses potential uses such as human–electronic interfaces, security applications and robotics.
Wang has also been experimenting with what he calls piezophotoelectronics. In this work, his concept to use lasers in tandem with piezoelectric gate materials to build functional on-off systems. For example, a laser can be used to raise the band gap between the p- and n- regions and shut off current flow, while the piezo material can turn it back on, and vice versa. This would be useful, for example, to tune and optimize photocells and improve photodetector capabilities. A piezophotoelectric LED is also in the works.
Wang is Regent’s Professor and director of the Center for Nanostructure Characterization at Georgia Tech.
For information on other areas of Wang’s research see:
Zhong-Lin Wang takes nanoscale piezo energy scavenging to heart
Creating alternating current with piezoelectrics
Learning from lizards how to improve dry adhesives
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