CU News
News from the University of Colorado in Boulder.
CU-Boulder wins $1.4 million NSF award for climate change, water sustainability study
Oct 10th
The University of Colorado at Boulder has been awarded $1.4 million for a new study on how changes in land use, forest management and climate may affect trans-basin water diversions in Colorado and other semi-arid regions in the western United States.
The grant, part of the National Science Foundation-U.S. Department of Agriculture Water Sustainability Climate Program, was awarded to Assistant Professor Noah Molotch of the geography department. Molotch and his team will be identifying thresholds, or “tipping points,” of change in land use, forest management and climate that may compromise the sustainability of the policies and procedures that dictate the timing and quality of water diverted from Colorado’s West Slope to the Front Range.
Molotch said that in Colorado and semi-arid regions around the world, trans-basin water diversions that redirect water from areas of surplus to areas of demand are based on policy agreements and infrastructure operations made under climatic and land use conditions that may differ considerably from conditions in the near future. Measurements over the past 50 years, for example, suggest a broad-scale reduction in snowpack water storage in the western U.S. because of regional warming temperatures, a trend due in part to a shift from snowfall to rainfall, he said.
The Colorado Big Thompson Project depends upon a dwindling supply of Western Slope snowpack.
In addition, land-cover changes associated with population growth, fire suppression and mountain pine beetle outbreaks have altered the hydrology of mid-mountain ecosystems in the West, said Molotch, who also is a scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. CU is teaming up with the National Center for Atmospheric Research in Boulder on the NSF-funded project.
The NSF award comes on the heels of a May 2012 agreement between water managers in Summit and Grand counties on Colorado’s West Slope and in the Denver area on how best to share water from the Colorado River basin. “This is a great example of communities that historically battled for water resources coming to the table in a good faith effort to find solutions to water allocation issues,” said Molotch. “These groups have no pretenses about the potential impacts of climate change and realize we can’t afford to bury our heads in the sand on this issue.”
Collaborators on the project include Patrick Bourgeron and Mark Williams, fellows at CU-Boulder’s Institute of Arctic and Alpine Research, and David Gochis, Kathleen Miller and David Yates of NCAR.
A study led by Molotch published Sept. 10 in Nature Geoscience tied forest “greenness” in the western United States to fluctuating year-to-year snowpack. The study indicated mid-elevation mountain ecosystems — where people increasing are building second homes and participating in a myriad of outdoor recreational activities — are most sensitive to rising temperatures and changes in precipitation and snowmelt.
“We found that mid-elevation forests show a dramatic sensitivity to snow that fell the previous winter in terms of accumulation and subsequent melt,” said Molotch, also a fellow at INSTAAR. “If snowpack declines, forests become more stressed, which can lead to ecological changes that include alterations in the distribution and abundance of plant and animal species as well as vulnerability to perturbations like fire and beetle kill.”
Colorado snowpack was at an all time low this past winter
As part of the new award, Molotch and his team will evaluate regional climate models in the mountain West developed at NCAR in an attempt to make temperature, precipitation and snowpack projections “more robust,” Molotch said. While the efficiency of water in trans-basin diversion projects in the western U.S. has in the past been enhanced by the natural storage of moisture in mountain snowpack that allowed for a slow, steady delivery of water into the system, warming temperatures are already causing this beneficial “drip effect” to be greatly reduced, he said.
If the winter temperatures are hovering around 15 degrees Fahrenheit and the climate warms by a few degrees, for example, there will be negligible impact on snowpack, Molotch said. But if temperatures hover near freezing, slight temperature increases can trigger earlier snowmelt, and precipitation that used to be in the form of snow turns to rain, significantly affecting trans-basin water diversion activities.
“One of the most interesting aspects of this project to me is the changes we are seeing in the ‘wildland-urban interface,’ particularly in Colorado,” he said. “There is some irony that Front Range people who have built second homes in Summit County, for example, may actually start to have an effect on the water they have relied on to be piped through the Continental Divide to the Denver area.”
Burned forests can cause early runoff
In addition to providing land and water resource decision makers with projections on how future water supply and demand will change in the future, the NSF-funded project will provide a unique educational experience for graduate students, Molotch said.
“We have climate change, snowpack, changes in land use, all feeding into the pipeline that is bringing water to Colorado’s Front Range,” he said. “As the two main stressors, climate change and land use increase, there is the possibility of pushing the systems into an unsustainable state.”
Nobel Prize-winner David Wineland praised as mentor to CU-Boulder graduate students
Oct 9th
David J. Wineland, a lecturer in the University of Colorado Boulder physics department who today won the 2012 Nobel Prize in physics, was described as both “brilliant and humble” by one of his former graduate students.
Wineland is a physicist with the National Institute of Standards and Technology in Boulder and internationally recognized for developing the technique of using lasers to cool ions to near absolute zero. His experiments have been used to test theories in quantum physics and may lead to the development of quantum computers. He shared the prize with Serge Haroche of France.
Wineland joined the CU-Boulder physics faculty as a lecturer in 2000 and currently works with four CU-Boulder graduate students pursuing doctorates, said physics department chair Paul Beale.
“It would be difficult to find a more brilliant and humble scientist,” said John Jost, who worked in Wineland’s group for about 10 years as a CU-Boulder doctoral student and postdoctoral researcher. “I feel lucky to have worked in his lab for my Ph.D. regardless of whether or not he won the Nobel Prize. He was always available when we had questions and problems in the lab and usually had some great idea about what to try next. At the same time, he gave us the freedom to figure things out on our own.”
In August, Jost began a Marie Curie fellowship as a postdoctoral researcher in the École Polytechnique Fédérale de Lausanne in Lausanne, Switzerland.
Wineland’s first demonstration of laser cooling in 1978 led many other scientists to pursue the laser cooling and trapping of atoms. His research helped make possible the creation of the world’s first Bose-Einstein condensate, for which Carl Wieman of CU and JILA and Eric Cornell of NIST and JILA and CU were awarded the Nobel Prize in physics in 2001. JILA is a joint institute of CU-Boulder and NIST.
Five CU-Boulder faculty members have now won individual Nobel Prizes. The other two winners are Tom Cech in chemistry and John “Jan” Hall in physics.
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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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