Archives—February 2014

ME-EM Graduate Seminar: 3D Audio

The ME-EM Graduate Seminar guest speakers on Thurs. Feb. 27 at 4:00 in 103 EERC will be Dr. Edgar Choueiri from Princeton University.

Title: 3D Audio

Starting with a brief review of the three main methods for 3-D sound reproduction over loudspeakers: 1) Wave Field Synthesis, 2) Ambisonics, and 3) Binaural audio through two loudspeakers (BAL), we focus on recent advances with the third method. I will show that crosstalk cancellation (XTC) allows BAL to deliver to the listener the necessary cues for real 3-D audio but that it inherently imposes an intolerably high spectral coloration on the audio. I will describe recent breakthroughs, which allow producing optimized XTC filters that impose no spectral coloration. I will then discuss the two other problems that have retarded the commercialization of XTC: the fixed and single sweet spot problems. I will show how the first problem is solved through advanced head tracking; and the second problem is solved using head tracking and phased array speakers, allowing the delivery of high-spatial-fidelity 3D audio to multiple moving listeners in real listening rooms. Following the talk, there will be a demo with playback of recorded music and natural sounds.

Edgar Choueiri is Professor of Applied Physics at at the Mechanical and Aerospace Engineering Department of Princeton University, and Associated Faculty at the Department of Astrophysical Sciences, Program in Plasma Physics. He is also Director of Princeton University’s Engineering Physics Program and Director of both the university’s Electric Propulsion and Plasma Dynamics Lab and its 3D Audio and Applied Acoustics (3D3A) Lab. He is the author for more than 175 scientific publications and the recipient of numerous awards and honors. His recent work on 3D audio has been featured by BBC Radio, NPR, The New Yorker magazine, The Discovery Channel, and The Atlantic magazine. His BACCH 3D Audio technology has been licensed by Princeton University and is commercially available in consumer and professional audio products.

ME-EM Graduate Seminar: Engineering the Past: Using Modern Engineering to Understand Historical Technologies

Mechanical Engineering – Engineering Mechanics Graduate Seminar; Thursday, Feb. 20, 2014 4:00 – 5:00 p.m. Room 103 EERC Bldg.; Steven A. Walton, PhD; Professor of History, Michigan Technological University

Title: Engineering the Past: Using Modern Engineering to Understand Historical Technologies

Amazing technical tasks have been accomplished in the past, from wonders like Stonehenge to the Wright Brothers biplane, but usually with little to no framework that we could conceive of as ‘science’. Modern engineering, on the other hand, has a vast range of scientific information with which to design and analyze new developments in technology, but it rarely stops to look back at how things worked in the past. These techniques can, however, offer great insight into historical technology, but it is often overlooked by historians who don’t know modern science and by engineers who don’t consider historical topics legitimate areas for analysis. This presentation will give a number of examples of historic technologies that have been recreated and analyzed with varying levels of engineering science, and then describe an ongoing research project on the “Origins of Firepower” that seeks to understand how early firearms were made, used, and understood. In particular, a number of research opportunities will be highlighted with regard to pre-modern gunpowder manufacture and combustion, as well as early artillery metrology and ballistics.

Dr. Walton holds degrees in Mechanical Engineering (B.S. Cornell; M.S. Caltech) and the History of Science and Technology (M.A., Ph.D ., Univ. of Toronto). He is own research on the history of technologies and the industries that made them spans the Middle Ages to the nineteenth century, and he works on both European and American topics. Most recently, he has two relevant projects underway that will appear in the talk: he is part of the Early European Guns and the Origins of Firepower research groups based in the UK and Denmark and in engaged in a series of surveys and projects to understand how gunpowder weaponry from the late 15th and 16th centuries behaved; in his work on 19th-cetntry American ordnance foundries, he is studying how the early understandings of strength of materials before the Civil War influenced artillery design and manufacture. He is long-term goal is to help find places where historical studies and engineering science can come together fruitfully to answering interesting historical questions.

ME-EM Graduate Seminar

The ME-EM Graduate Seminar guest speakers on Thurs. Feb. 13 at 4:00 in 103 EERC will be Dr. David Harvey from Ballard Power Systems.

Title: Challenges, Opportunities, and Open-source A perspective on Fuel Cell simulation for performance and durability

Proton Exchange Membrane Fuel Cells have been a prominent part of the alternative energy landscape for a considerable length of time. The challenges facing the technology are generally categorized into three main areas: Cost, Performance, and Durability. These three areas are for the most part largely intertwined, as changes in materials or designs that improve one area invariably have, for the most part, a negative effect on the others. Of particular focus in recent initiatives has been the catalyst layer, specifically the performance and durability of a three part system of a supporting particle, nano-catalyst, and ionomeric “binder”. To date, very few commercial numerical codes exist that can adequately describe state-of-the-art PEM fuel cell performance or durability. To a large extent this is a product of the speed at which the materials development and theoretical understanding is moving, such that commercial codes tend to lag in capability as the “investment” to stay current is immense. Open-source initiatives have become commonplace in many areas, one of which is computational fluid dynamics. The open nature of these codes has led to the development of “current” sets of theory and physics in various application areas and the community nature of the projects enables and encourages leverage in other areas of engineering and design. This methodology has been applied to the development of a free and open-source software initiative, FCAPOLLO that has been built on a free and open-source CFD package.

David is a researcher in the field of alternative energy. He has been working in the area of proton exchange membrane (PEM) fuel cells since 2002 with a focus on the development of numerical simulations for performance and durability. In 2005, David began working for Ballard Power Systems in Burnaby, BC on the development of simulation codes to predict the performance of membrane electrode assemblies (MEAs). During that time, he and his group, in coordination with researchers at Queen’s University in Kingston, Onario, were the first to develop a stoichastic technique for the direct numerical simulation of catalyst layers. This work transitioned into the U.S. Department of Energy project, “Microstructural Mitigations Strategies: Morphological Simulations and Experimental Approaches” in which a series of simulations at scales ranging from nano to macro were coupled in a multi-scale modelling methodology in order to assess and predict the performance and degradation of carbon-supported platinum nano-catalysts. His current area of foucs is on the development of the software derived from the U.S. Department of Energy Project, FC-APOLLO. FC-APOLLO is a free, open-source fuel cell design software built in the opensource CFD package
OpenFOAM (trademark of OpenCFD).

It’s the Water: Graphene Balloon Yields Unprecedented Images of Hydrated Protein Molecules

A graphene water balloon may soon open up new vistas for scientists seeking to understand health and disease at the most fundamental level.

Electron microscopes already provide amazingly clear images of samples just a few nanometers across. But if you want a good look at living tissue, look again.

“You can’t put liquid in an electron microscope,” says Tolou Shokuhfar, of Michigan Technological University. “So, if you have a hydrated sample—and all living things are hydrated—you have to freeze it, like a blueberry in an ice cube, and cut it into a million thin pieces, so the electrons can pass through. Only then can you image it to see what’s going on.”