Posts tagged CU
CU study: Graphene membranes may lead to enhanced natural gas production, less CO2 pollution
Oct 8th
Engineering faculty and students at the University of Colorado Boulder have produced the first experimental results showing that atomically thin graphene membranes with tiny pores can effectively and efficiently separate gas molecules through size-selective sieving.
The findings are a significant step toward the realization of more energy-efficient membranes for natural gas production and for reducing carbon dioxide emissions from power plant exhaust pipes.
Mechanical engineering professors Scott Bunch and John Pellegrino co-authored a paper in Nature Nanotechnology with graduate students Steven Koenig and Luda Wang detailing the experiments. The paper was published Oct. 7 in the journal’s online edition.
The research team introduced nanoscale pores into graphene sheets through ultraviolet light-induced oxidative “etching,” and then measured the permeability of various gases across the porous graphene membranes. Experiments were done with a range of gases including hydrogen, carbon dioxide, argon, nitrogen, methane and sulphur hexaflouride — which range in size from 0.29 to 0.49 nanometers — to demonstrate the potential for separation based on molecular size. One nanometer is one billionth of a meter.
“These atomically thin, porous graphene membranes represent a new class of ideal molecular sieves, where gas transport occurs through pores which have a thickness and diameter on the atomic scale,” said Bunch.
Graphene, a single layer of graphite, represents the first truly two-dimensional atomic crystal. It consists of a single layer of carbon atoms chemically bonded in a hexagonal “chicken wire” lattice — a unique atomic structure that gives it remarkable electrical, mechanical and thermal properties.
“The mechanical properties of this wonder material fascinate our group the most,” Bunch said. “It is the thinnest and strongest material in the world, as well as being impermeable to all standard gases.”
Those characteristics make graphene an ideal material for creating a separation membrane because it is durable and yet doesn’t require a lot of energy to push molecules through it, he said.
Other technical challenges will need to be overcome before the technology can be fully realized. For example, creating large enough sheets of graphene to perform separations on an industrial scale, and developing a process for producing precisely defined nanopores of the required sizes are areas that need further development. The CU-Boulder experiments were done on a relatively small scale.
The importance of graphene in the scientific world was illustrated by the 2010 Nobel Prize in physics that honored two scientists at Manchester University in England, Andre K. Geim and Konstantin Novoselov, for producing, isolating, identifying and characterizing graphene. Scientists see a myriad of potential for graphene as research progresses, from making new and better display screens and electric circuits to producing tiny biomedical devices.
The research was sponsored by the National Science Foundation; the Membrane Science, Engineering and Technology Center at CU-Boulder; and the DARPA Center on Nanoscale Science and Technology for Integrated Micro/Nano Electromechanical Transducers at CU-Boulder.
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CU study says Romney will be Pres
Oct 4th
Updated election forecasting model
still points to Romney win,
University of Colorado study says
still points to Romney win,
University of Colorado study says
An update to an election forecasting model announced by two University of Colorado professors in August continues to project that Mitt Romney will win the 2012 presidential election.
According to their updated analysis, Romney is projected to receive 330 of the total 538 Electoral College votes. President Barack Obama is expected to receive 208 votes — down five votes from their initial prediction — and short of the 270 needed to win.
The new forecast by political science professors Kenneth Bickers of CU-Boulder and Michael Berry of CU Denver is based on more recent economic data than their original Aug. 22 prediction. The model itself did not change.
“We continue to show that the economic conditions favor Romney even though many polls show the president in the lead,” Bickers said. “Other published models point to the same result, but they looked at the national popular vote, while we stress state-level economic data.”
While many election forecast models are based on the popular vote, the model developed by Bickers and Berry is based on the Electoral College and is the only one of its type to include more than one state-level measure of economic conditions. They included economic data from all 50 states and the District of Columbia.
Their original prediction model was one of 13 published in August in PS: Political Science & Politics, a peer-reviewed journal of the American Political Science Association. The journal has published collections of presidential election models every four years since 1996, but this year the models showed the widest split in outcomes, Berry said. Five predicted an Obama win, five forecast a Romney win, and three rated the 2012 race as a toss-up.
The Bickers and Berry model includes both state and national unemployment figures as well as changes in real per capita income, among other factors. The new analysis includes unemployment rates from August rather than May, and changes in per capita income from the end of June rather than March. It is the last update they will release before the election.
Of the 13 battleground states identified in the model, the only one to change in the update was New Mexico — now seen as a narrow victory for Romney. The model foresees Romney carrying New Mexico, North Carolina, Virginia, Iowa, New Hampshire, Colorado, Wisconsin, Minnesota, Pennsylvania, Ohio and Florida. Obama is predicted to win Michigan and Nevada.
In Colorado, which Obama won in 2008, the model predicts that Romney will receive 53.3 percent of the vote to Obama’s 46.7 percent, with only the two major parties considered.
While national polls continue to show the president in the lead, “the president seems to be reaching a ceiling at or below 50 percent in many of these states,” Bickers said. “Polls typically tighten up in October as people start paying attention and there are fewer undecided voters.”
The state-by-state economic data used in their model have been available since 1980. When these data were applied retroactively to each election year, the model correctly classifies all presidential election winners, including the two years when independent candidates ran strongly: 1980 and 1992. It also correctly estimates the outcome in 2000, when Al Gore won the popular vote but George W. Bush won the election through the Electoral College.
In addition to state and national unemployment rates, the authors analyzed changes in personal income from the time of the prior presidential election. Research shows that these two factors affect the major parties differently: Voters hold Democrats more responsible for unemployment rates, while Republicans are held more responsible for fluctuations in personal income.
Accordingly — and depending largely on which party is in the White House at the time — each factor can either help or hurt the major parties disproportionately.
In an examination of other factors, the authors found that none of the following had a statistically significant effect on whether a state ultimately went for a particular candidate: The location of a party’s national convention, the home state of the vice president or the partisanship of state governors.
The authors also provided caveats. Their model had an average error rate of five states and 28 Electoral College votes. Factors they said may affect their prediction include the timeframe of the economic data used in the study and that states very close to a 50-50 split may fall in an unexpected direction due to factors not included in the model.
“As scholars and pundits well know, each election has unique elements that could lead one or more states to behave in ways in a particular election that the model is unable to correctly predict,” they wrote.
All 13 election models can be viewed on the PS: Political Science & Politics website at http://journals.cambridge.org/action/displayJournal?jid=PSC.
CU SNR team: Natural gas development to get a hard look
Oct 2nd
NSF awards CU-Boulder-led team $12 million
to study effects of natural gas development
to study effects of natural gas development
The National Science Foundation has awarded a $12 million grant to a University of Colorado Boulder-led team to explore ways to maximize the benefits of natural gas development while minimizing negative impacts on ecosystems and communities.
Led by Professor Joseph Ryan of CU-Boulder’s civil, environmental and architectural engineering department, the team will examine social, ecological and economic aspects of the development of natural gas resources and the protection of air and water resources. A part of NSF’s Sustainability Research Network initiative, or SRN, the project will focus on the Rocky Mountain region, where natural gas development, as well as objections to it, are increasing.
“We all create demand for natural gas so we have to accept some of the outcomes of its extraction,” said Ryan. “Our goal is to provide a framework for society to evaluate the trade-offs associated with the benefits and costs of natural gas development.”
The SRN team assembled by Ryan includes air and water quality experts, social scientists, human health experts, information technology experts and a substantial outreach and education effort. The SRN team will be advised by an external committee that includes representatives of the oil and gas industry, regulatory agencies, environmental organizations, local governments, academia and Native American tribes. Preparation of the SRN proposal to the NSF was fostered by CU-Boulder’s Office for University Outreach, which supported the creation of the Colorado Water and Energy Research Center, said Ryan.
As part of the effort, Ryan said team members will review industry practices for hydraulic fracturing, which involves pumping pressurized water, sand and chemicals deep down well bores to crack rocks and free petroleum and natural gas for easier extraction. The team will evaluate the current state of drilling technology, the integrity of well bore casings and natural gas collection mechanisms and processes.
- Drill pads around the Roan Plateau
- Hydraulic fracturing requires large volumes of chemically treated water — most wells require between 3 million and 5 million gallons of water each, say experts. The fracturing fluid left in the ground, as well as the fluid that returns to the surface, known as “flowback,” present potential ecological and health risks if not handled properly, Ryan said.
While oil and gas extractions from hydraulic fracturing also result in atmospheric emissions of some greenhouse gases and volatile organic compounds, natural gas is nevertheless seen by many as a “bridge fuel” that leads away from dirty coal combustion toward cleaner sustainability methods, said Patrick Bourgeron, associate director of the SRN and a fellow at CU-Boulder’s Institute for Arctic and Alpine Research.
As part of the project, a team led by CU-Boulder Professor Harihar Rajaram will be investigating the hydrologic processes tied to potential risks of natural gas and oil extraction, including groundwater and aquifer systems. The team also plans to assess the risk of natural gas and oil extraction to water quality and mitigation strategies that involve improvements in current water treatment technology.
Professor Jana Milford of CU-Boulder’s mechanical engineering department will lead a team monitoring and modeling the potential risks of natural gas and oil development to air quality. Professor John Adgate of the Colorado School of Public Health in Denver will spearhead a team assessing the potential risks of natural gas development to public health.
Natural gas waste pit
Other partners on the CU-led NSF project include the Colorado School of Mines, Colorado State University, the University Corporation for Atmospheric Research in Boulder, the National Renewable Energy Laboratory in Golden, Colo., the National Oceanic and Atmospheric Administration, the University of Michigan and California State Polytechnic University Pomona.
Attitudes toward natural gas extraction using hydraulic fracturing vary widely around the West, said CU-Boulder Professor Mark Williams, a co-investigator on the project. One classic Colorado example is Boulder County and adjoining Weld County to the northeast. “The geology doesn’t change, the price of gas doesn’t change and the extraction methods are the same,” he said. “But for the most part, Boulder County opposes hydraulic fracturing while Weld County generally embraces it.”
Ryan said the network’s research findings eventually will be shared with the public through an extensive outreach and education effort led by SRN co-investigator and CU-Boulder Professor Patricia Limerick of the Center of the American West. The effort includes a “citizen science” component in which the public is encouraged to make science measurements, including air quality readings made with portable instruments compatible with smart phones, and share the results with the SRN research team.
“The citizen science aspect of this effort will result in a stronger connection between the public and the science used to make regulatory decisions,” said Professor Michael Hannigan of CU-Boulder’s mechanical engineering department and one of the co-investigators on the SRN project.
Natural gas production, especially the use of hydraulic fracturing, has become the subject of intense controversy, said Limerick. “Some people living in proximity to well sites are understandably worried and anxious, often feeling powerless as they confront a possible threat to their health and to the quality of their lives.
“Environmental advocates find themselves pulled between the climate benefits of natural gas, which releases significantly less carbon in combustion than coal, and the disturbances associated with natural gas extraction,” she said.
Outreach events will include periodic town hall meetings around the West. There also will be SRN meetings involving engineers, natural scientists and social scientists to stay abreast of the latest technologies and evolving socioeconomic factors regarding natural gas production, Limerick said.
“Unraveling complex processes involving Earth systems, especially the coupling of human activities and climate, depends increasingly on partnerships among natural science, philosophy and ethics, economics, social science, mathematics and engineering,” says Marge Cavanaugh, NSF acting assistant director for geosciences.
The CU-led research team and a second team from Penn State were chosen from more than 200 SRN proposals by the NSF as part of its Science, Engineering and Education for Sustainability program. The $12 million award to CU-Boulder is for five years.
