Just Published
Risk Assessment in Geotechnical Engineering
Soils and rocks in their natural state are among the most variable of all engineering materials, and geotechnical engineers must often “make do” with materials that present themselves at a particular site. This makes geotechnical engineering highly amenable to a probabilistic treatment. A new text co-authored by Vaughan Griffiths, professor of civil engineering at Mines, and Gordon Fenton, a professor at Dalhousie University in Nova Scotia, describes the use of probabilistic methods applied to geotechnical engineering applications. Risk Assessment in Geotechnical Engineering details methodologies in which soil properties are characterized statistically, to generate a “probability of failure” or “reliability.” When these values are weighted by the consequences of failure, engineers can then assess the “risk” associated with a given design. Specific examples might involve the probability of slope failure in an embankment dam or unacceptable foundation settlement under a nuclear power plant. Risk assessment is a rapidly growing field of interest, not only for academics and practitioners, but also the insurance industry. (John Wiley & Sons, New Jersey, 2008)

Adaptive Pitch Control of Variable-Speed Wind Turbines

In a paper written by Kathryn Johnson, assistant professor of electrical engineering, and Lee Jay Fingersh, a senior engineer with NREL, the efficiency of advanced control systems in wind turbines is discussed. One of the goals of wind turbine research is to obtain more electrical energy without increasing the cost of the wind turbine. If more energy is produced for the same turbine cost, the cost of energy from wind will decrease, allowing utilities to pass along savings to consumers. This research paper describes a method that has been shown in computer simulations and on a real wind turbine to increase the amount of power generated using relatively inexpensive control systems that adapt the pitch of the blade based on a variety of factors, including dynamic data on wind velocity and the speed of rotation. (Journal of Solar Energy Engineering, Vol. 130, No. 3, pp. 031012-1 – 031012-7)

The Availability of Global Fossil Energy

Roberto F. Aguilera PhD ’06 recently published The Availability of Global Fossil Energy which focuses on concern in the energy industry about an approaching global crisis caused by peak oil production. It assesses the threat that depletion poses by estimating cumulative supply curves for conventional and unconventional petroleum resources. The results indicate that large quantities are available and can be produced at costs substantially below current market oil prices. These findings suggest that fossil energy is likely to last far longer than many are now predicting and that depletion need not drive market prices above the relatively high levels prevailing over the past several years. Currently, Aguilera is a program officer and research scholar with the International Institute for Applied Systems Analysis. (VDM Publishing House, 2008).

Inverse Problems

Inverse problems are a common mathematical challenge in fields such as geophysics, astrophysics and medical imaging, which involve recovering an image or set of parameters from indirect “noisy” observations. For example, non-intrusive imaging is used to detect anomalies in the brain. But, how significant are the features a doctor may observe in an image? The characterization of solution uncertainty is an essential aspect of the study of inverse problems. In recent years, the development of computational technology has combined with advances in statistical methods to create unprecedented opportunities to understand and explore the role of uncertainty in inversion. Luis Tenorio, associate professor of mathematical and computer sciences, organized a special section of the journal Inverse Problems to expose the inverse problems community to some of the latest statistical and computational methods that are important for inverse problems. (Inverse Problems, Guest Eds. L. Tenorio, E Haber, W. W. Symes, P. B. Stark, D. Cox and O. Ghattas. 24:3, June 2008)

Earthquake Decision-Making and Response

ShakeMap is a well-established tool used to portray the extent of potentially damaging shaking following an earthquake. ShakeCast, also known as ShakeMap Broadcast, is a freely available and fully automated system capable of triggering established post-earthquake response protocols that was recently covered in Earthquake Spectra and featured on its cover. ShakeCast was developed by a team of four that was led by David Wald, an adjunct associate professor of geophysics
and a supervisory research geophysicist for the USGS’s National Earthquake Information Center based on campus. The product was designed for emergency response, loss estimation and improving the availability of information to the public after an earthquake. ShakeCast compares a quake’s complex shaking distribution with the damageability of a user’s properties, providing simple hierarchical information
on structures or facilities most likely impacted by an event. For example, the California Department of Transportation relies on ShakeCast for prioritizing inspections on their 12,000 or so bridges after an earthquake. (“ShakeCast: Automating and Improving the Use of ShakeMap for Post-Earthquake Decision-Making and Response,” D. J. Wald, K. Lin, K. Porter, and L. Turner, Earthquake Spectra, 24:2, 533-553. http://earthquake.usgs.gov/shakecast/.)