Dr Ashwin Seshia
Fellow, Department of Electrical Engineering, Queens' College, University of Cambridge
Reader in Microsystems Technology
On Sabbatical at UC Berkeley
February 16, 2016 | 12:00 to 01:00 | 490 Cory Hall
Host: John Huggins
Instruments based on resonant and oscillatory elements have historically been employed to conduct some of the most accurate physical measurements. This talk describes research to enable miniaturized electromechanical sensor systems wherein precise engineering of the dynamic response is instrumental in enabling new modes of transduction, energy conversion, and sensing. A series of research results from my group will be provided to illustrate the approach.
First, seismic-grade accelerometers based on resonant output principles will be described where the interaction of mechanical nonlinearities and noise processes sets limits on the achievable resolution. Further, by engineering the principle of vibration mode localization in weakly coupled resonators, passive immunity to environmental drift is achieved by recording eigenstate variations as a measure of differential structural perturbations.
Next, net-zero power strain sensors for structural health monitoring applications are enabled by integrating vibration energy harvesters together with low-power temperature-compensated resonant strain gauges. By engineering the principle of parametric resonance for vibration energy harvesting, it is possible to engineer vibration energy harvesters with multi-frequency responsivity and substantially larger recoverable electrical power, as compared to classical approaches based on direct (linear) resonance under specified conditions.
Finally, with a view toward future applications of engineered non-linearity in micro- and nanoelectromechanical systems, I will describe results from electro-acoustic biosensors utilizing noise and non-linear response as readout modalities, and the mutual synchronization of non-linear microelectromechanical oscillators demonstrating significantly improved frequency stability and potentially enabling fundamentally new energy-efficient approaches to sensory information processing. Micro- and nanofabricated devices engineered using these and similar approaches are now being integrated into monitoring tools and sensor systems for a variety of application scenarios.
nanoscience.cam.ac.ukandeng.cam.ac.uk/~aas41
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