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Posted by: mus41 on Nov 16, 2016
Bo Cheng
Department of Mechanical and Nuclear Engineering, PSU

Wednesday, November 29, 2016 3:35pm - 4:25pm
103 Leonhard Building

As the first animals on earth to evolve aerial locomotion, insects took off into the sky 350 million years ago and have been experimenting successfully with aerodynamics, sensory systems and flight control though evolution. They have developed sophisticated design of flight sensing, control and actuation system that allow them to master the complex physics in their living environments and achieve supreme stability and maneuverability. These relatively simple, but also sophisticatedly designed flying machines offer us a treasure trove of scientific problems and inspirations for engineering designs. Decoding the secret of insect flight demands multi-disciplinary approaches that interconnect engineering, mathematics and biology. Our research starts from assessing the flight performance of insects and hummingbirds using a variety of experiments and then through using biomimetic robotic devices, dynamic modeling, control theories and fluid experiments, we work towards understanding the flight dynamics, sensorimotor control and aerodynamics of insect flight. Eventually, the knowledge of insect flight will serve as the basis to develop millimeter-scale micro air vehicles (MAVs) in the future.

Dr. Cheng is an Assistant Professor of Mechanical Engineering at Penn State. Prior to this, he was a Postdoctoral Research Associate in the School of Mechanical Engineering at Purdue University, where he received his Ph.D. in 2012. He also received his M.S. in Mechanical Engineering from University of Delaware and B.S. from Control Science & Engineering at Zhejiang University, China. His research interests include biomechanics and sensorimotor control of animal flight, aerodynamics at low Reynolds number and biologically inspired robotics. Working in a highly interdisciplinary field, Dr. Cheng's work has been published in journals from many disciplines, such as Science, IEEE Trans on Robotics, Journal of Experimental Biology, Experiments in Fluids and Journal of the Royal Society Interface. Dr. Cheng received National Science Foundation (NSF) Early Career Development (CAREER) Award in 2016.
Posted by: mus41 on Nov 9, 2016
Nitin Sharma
Department of Materials Science and Engineering, University of Pittsburgh

Wednesday, November 16, 2016 3:35pm - 4:25pm
103 Leonhard Building

Functional Electrical Stimulation (FES) can be used to artificially activate paralyzed lower limb muscles to restore walking and standing function in persons with neurological disorders. Despite its potential, FES-based walking neuroprosthesis has achieved limited acceptability among persons with paraplegia. This is primarily due to the early onset of muscle fatigue during FES and difficulty in obtaining a consistent and reliable response from the paralyzed muscle using traditional control methods.

We are employing a hybrid strategy that integrates FES with a powered exoskeleton to overcome these hurdles. This hybrid strategy has several advantages. The main advantage is that the effects of muscle fatigue and any inconsistent response from FES can be compensated by the active exoskeleton. This can potentially lead to improved functional mobility in users with neurological impairments. Other advantages include reduced overall weight of the exoskeleton and neuroplastic improvements in the neuromuscular system due to FES.

However, closed-loop control methods are required to effectively integrate FES with a powered exoskeleton because the hybrid combination leads to redundancy in actuation and needs a criteria to allocate control between FES and an electric motor. I will be presenting algorithms and models that were recently developed by our research group to control the hybrid exoskeleton. These methods include 1) a muscle fatigue model to inform the onset of muscle fatigue and muscle recovery during FES, 2) Shared control of FES and electric motor based on the fatigue model, and 3) muscle synergy inspired control of a hybrid walking exoskeleton.

Nitin Sharma received his Ph.D. degree from the Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, in 2010. He was an Alberta Innovates-Health Solutions postdoctoral Fellow in the Department of Physiology at the University of Alberta, Edmonton, Canada. Since 2012, he is an Assistant Professor in the Department of Mechanical Engineering and Materials Science at the University of Pittsburgh. His research interests are modeling, optimization, and control of functional electrical stimulation-elicited walking. His current research in hybrid exoskeletons is funded by two NSF awards and one NIH R03 Award.

Posted by: mus41 on Nov 2, 2016
Wei-Heng Shih
Department of Materials Science and Engineering, Drexel University

Wednesday, November 9, 2016 3:35pm - 4:25pm
103 Leonhard Building

We have developed a method of coating Mg(OH)2 layer on Nb2O5 particles that facilitated the direct, one-step, sintering of piezoelectric lead magnesium niobate-lead titanate (PMN-PT) freestanding sheets. The piezoelectric freestanding sheets were used to develop a novel Piezoelectric Plate sensor (PEPS). By immobilizing receptors specific to target antigens on the PEPS surface, binding of target antigens such as cells, viruses, proteins, and DNA in various liquid environments to the receptor on the sensor surface causes the PEPS resonance frequency to shift. For example, PEPS can rapidly (< 30 min) detect double-stranded DNA at a concentration of 60 copies/ml point mutation in the background of 1000 times wild type in urine or serum and genetic signature of bacteria at 150 copies/ml in stool without isolation, concentration, and amplification. PEPSís enhanced detection sensitivity is related to the easy domain switching in PMN-PT layer caused by the target antigen binding to the sensor surface. .
Meanwhile, we have also developed an environmentally friendly aqueous method to synthesize aqueous quantum dots (AQDs) using mercaptopropionic acid (MPA). Due to high coverage of the capping molecules, AQDs exhibited a better than 80% conjugation efficiency and were colloidally stable. Visible and Near-infrared (NIR) AQDs were used to create a molecular probe to image cancer cells on tumors to help surgeons determine whether all cancer cells have been removed in the operating room. More recently, we studied the synthesis of organohalide perovskite materials to develop highly photoluminescent nanocrystals as well.

Wei-Heng Shih received a B.Sc. in physics in 1976 from Tsing-Hua University in Taiwan and completed his Ph.D. degree in Physics in 1984 from Ohio State University. He joined the Department of Materials Science and Engineering at Drexel University in 1991 and was promoted to Professor in 2003. His research has covered colloidal processing of ceramics; sol-gel processing of microporous and mesoporous ceramic powders; and chemical treatment of combustion wastes. His current research interests are fabrication, characterization and design of piezoelectric plate sensors and the development of environmentally friendly synthesis of photoluminescent nanocrystals (quantum dots) for biomedical and optoelectronic applications. Prof. Shih has 132 published journal papers, 32 patents and 24 patents in application. He received the 1999 Edward C. Henry Electronics Division Best Paper Award from The American Ceramic Society and was elected a Fellow of National Academy of Inventors in 2013. In Drexel University, he has received several awards including the Faculty Achievement Award, Professor of the Year, and the Research Achievement Award. His technologies have been licensed by four companies.