"Chaos Tamed" - Extraction signal from noise
For the geophysicist, noise and randomness are usually undesirable. But in an essay published last summer in Nature (vol. 447, p.643),entitled, "Chaos Tamed," Geophysics Professor Roel Snieder, along with his colleague Kees Wapenaar at Delft University of Technology, Netherlands, demonstrates that randomness can actually help in a new technology used for imaging. In normal imaging, as used for example with radar or seismic exploration, a source excites waves that bounce back from a target. However, in previous theoretical research it was discovered that an active source is not really needed, and that random noise can be used for imaging. For seismic imaging this noise can have cultural sources, such as traffic, or it may be natural, such as waves breaking. According to the underlying theory, the noise sources must be distributed everywhere, but in practice one can violate this to a remarkable degree. Snieder carries out an active research program on the extraction of information from noise with colleagues at Shell Research in Houston and with Kees Wapenaar at Delft University of Technology in the Netherlands.
Spiral Form in Nature and Engineering
The utility of wine openers rests on a familiar principle, the coupling between twist and translation. The form that sets the function in motion is the handedness of the cork-screw, or the sign of the coupling. A recent study by Engineering Division student Dr. Hailong Want and Professor Moneesh Upmanyu published in the Journal of the Royal Society Interface (available online: http://dx.doi.org/doi:10.1098/rsif.2007.1145) shows that the coupling in more flexible slender rods such as DNA can change sign, a combination of how the stretch is accommodated and handedness. The study settles the rather curious puzzle as to why DNA overwinds when stretched, with implications in nature and technology. Unsurprisingly, this is not news to Mother Nature, with examples ranging from spiral growth in fungi to propulsion in rod-like bacteria. An easily observable example is the change in spiral grain structure in certain pine trees. The study was sponsored by National Science Foundation and was also featured in the October 2007 Materials Research Society newsletter.
Pollution Prevention - Bio-based Materials and Energy
Chemical Engineering Professor John Dorgan and former faculty member Dr. Dianne Ahmann have coauthored a new EPA report entitled Bioengineering for Pollution Prevention Through Development of Biobased Materials and Energy. The 173-page document examines scientists' understanding of plant matter and other bio-based alternatives to petroleum for materials and energy. The report examines progress made towards using plants, plant oils and microbes for plastics and fuels, as well as the challenges for using these alternatives on scales large enough to meet society's needs and still protect the environment. The report documents the extent to which economies around the world are dependent on petroleum. As demand for petroleum increases and supplies diminish, petroleum-based economies need to move to plastics and fuels that are renewable, domestically available and more environmentally friendly. Scientists and engineers are exploring many options through the field of industrial biotechnology, and results of some of their research are reviewed in this report. With recommendations for further action, the report encourages scientific discussion and identifies potential opportunities for interdisciplinary research. The report is now available at the EPA's research homepage: http://es.epa.gov/ncer/events/news/2007/07_18_07_feature.html.