Evan Variano
UC Berkeley

HOST: Eric Loth
Time: 4:00 pm
Place: MEC 341
Refreshments at 3:30PM in MEC 341

Phillip H Snyder, Ph.D.
Engineering Associate Fellow
Rolls-Royce
HOST: Eric Loth

Time: 4:00 pm
Place: MEC 341
Refreshments at 3:30PM in MEC 341

Sriram Rallabhand
Senior Research Engineer
National Institute of Aerospace

HOST: Robert Lindberg

Time: 4:00 pm
Place: MEC 341
Refreshments at 3:30PM in MEC 341

Skylab Astronaut Jerry Carr will be visiting the University of Virginia on Tuesday, September 11. He will give a public lecture about his experiences orbiting the earth for 84 days. His presentation is scheduled for 2 pm in the Auditorium of the Harrison Institute/Small Special Collections Library.

The occasion for this visit is the selection of UVa 3rd year engineering student Ellen Zhong to receive a $10,000 scholarship from the Astronaut Scholarship Foundation. Ellen is the second UVa student to receive this award, and she will be honored at this event. The scholarship is intended for undergraduate students in mathematics, engineering, and the sciences who wish to conduct research and advance their field.

All are welcome to attend. Those present will be eligible for a fantastic door prize: A Fujifilm FinePix S2980 Bundle 14-megapixel, 18X high-zoom camera with case and 4GB memory card.

Speaker: Do-Nyun Kim, PhD
Department of Biological Engineering
Massachusetts Institute of Technology

Date: Thursday, April 26, 2012
Time: 4:00 pm
Place: MEC 341
Refreshments at 3:30PM in MEC 341

Abstract:

DNA nanotechnology enables construction of sophisticated nanometer-scale structures for diverse applications in materials and biological science. Scaffolded DNA origami is a successful approach to synthesize DNA-based nanostructures with precise control over their three-dimensional shape and mechanical properties. Predictive computational tools are essential to enable the rational design of these structures that meet structural and mechanical specifications. Towards this end, here I present a computational framework for DNA-based nanostructure design that employs the finite element method to predict the equilibrium solution shape, thermally induced fluctuation amplitude, mechanical properties, and defect propensity of DNA origami structures. The present computational framework, which is provided as a public web-based tool called CanDo (Computer-aided engineering for DNA origami, http://cando.dna-origami.org), is expected to significantly increase the number and variety of synthetic DNA-based nanostructures.

Biography:

Dr. Do-Nyun Kim is currently a postdoctoral associate at MIT working under supervision of Prof. Mark Bathe in the Department of Biological Engineering. He received his BS and MS degrees in the School of Mechanical and Aerospace Engineering from Seoul National University in 2000 and 2002, respectively, and completed his PhD degree in the Department of Mechanical Engineering at MIT in 2009. He was appointed as an instructor at Korea Air Force Academy from 2002 to 2005. His expertise spans a broad range of computational solid/structural mechanics including the finite element method, mechanics of aerospace structures, anisotropic elasto-plasticity, plate and shell theories, continuum modeling of protein dynamics, and computational DNA nanotechnology.

Speaker: Efstathios Bakolas, PhD
School of Aerospace Engineering
Georgia Institute of Technology

Date: Tuesday, April 24, 2012
Time: 4:00 pm
Place: MEC 341
Refreshments at 3:30PM in MEC 341
Abstract:

The recent technological advances in the field of autonomous vehicles have resulted in a growing impetus for researchers to improve the current framework of mission planning and execution within both military and civilian contexts. The interest in applications involving autonomous vehicles is expected to grow significantly in the near future as new paradigms for their use are constantly being proposed for a diverse spectrum of real world applications. In this talk I will present a framework for addressing vehicle-target assignment problems involving either groups of spatially distributed autonomous vehicles and/or targets that is aimed at reducing the complexity of the assignment problem. In particular, I will introduce a Voronoi-type partition of the space populated by the vehicles and the targets, such that each set of this partition corresponds to the “area of influence” of a particular vehicle or target. The key feature of the proposed partitioning scheme is that the proximity relations between the vehicles and the targets are induced by state-dependent (pseudo-) metrics, such as the minimum time-to-go, rather than the Euclidean distance or other generalized distance functions used in the literature. These state-dependent metrics can, in contrast to more “conventional” distance functions, succinctly capture essential features of the vehicle’s maneuverability as well as the environment-vehicle interactions, which are induced, for example, by local winds/currents. Subsequently, I will illustrate how the proposed concept of state-dependent spatial partition can be applied to a group pursuit problem of a maneuvering target as well as a multi-target version of the Zermelo navigation problem for a small UAV in the presence of a strong wind field and/or when the ensuing path of the UAV satisfies the explicit curvature constraints of the Markov-Dubins problem.

Bio: Efstathios Bakolas is a Post-doctoral Fellow in the School of Aerospace Engineering at the Georgia Institute of Technology. He received his Diploma in Mechanical Engineering from the National Technical University of Athens, Greece, in 2004 and his MS. and PhD. degrees in Aerospace Engineering from Georgia Institute of Technology in 2007 and 2011, respectively. His current research interests are in the area of guidance, navigation, and control with an emphasis on applications of autonomous vehicles using optimal control and differential game theory.

Speaker: Dr. Allison Beese
Department of Mechanical Engineering
Northwestern University

Date: Thursday, April 19, 2012
Time: 4:00 pm
Place: MEC 341
Refreshments at 3:30PM in MEC 341

Abstract:

Steels remain one of the most widely used structural materials, and new grades of steels are constantly being developed. Advanced High Strength Steels (AHSS) are a particularly attractive class of steels, as they offer increased strength without sacrificing ductility, lending themselves to the application in lightweight vehicle structures where high mass specific energy absorption is critically important.

Metastable austenitic steels belong to the class of AHSS. They offer a combination of high strength and ductility, which is attributed to their characteristic deformation-induced phase transformation. I will present the development of an anisotropic plasticity model that describes the constitutive behavior of stainless steel 301LN sheets that undergo phase transformation from austenite to martensite. The plasticity model is composed of an anisotropic yield function, an isotropic hardening law, and a nonlinear kinematic hardening law. Additionally, an initial back stress is used to account for the material’s temper-rolling processing history. The microstructural evolution is incorporated into the isotropic hardening law using a stress-state dependent transformation kinetics law that describes the austenite-to-martensite transformation in terms of strain, stress triaxiality, and Lode angle. The plasticity model is calibrated using experimental data, and the subsequent model predictions agree well with the experimental results over a wide range of stress states including uniaxial tension, uniaxial compression, pure shear, transverse plane strain tension and equi-biaxial tension.

Speaker: Professor Michael Zachariah
Mechanical Engineering and Chemistry
University of Maryland

Date: Thursday, April 12, 2012
Time: 4:00 pm
Place: MEC 34
Refreshments at 3:30PM in MEC 341

Abstract:

The high temperature reactivity of metal/metal oxides are important in a wide variety of industrial applications including solar-thermal hydrogen generation, CO2 sequestering, chemical-looping combustion, and energetic materials, among others. In this seminar I will discuss the reactivity of nanometals and metal oxides, towards developing a conceptual picture of rate limiting and phenomenological processes, in particular for application to energetic materials. This discussion will naturally lead to what makes nanoscale materials attractive for these applications, as well as some of their limitations.

Biography

Michael Zachariah is the founding Director of the University of Maryland/NIST Center for NanoManufacturing and Metrology and was the founding Director of the Army Center for Nanoenergetics Research. He has published extensively on the metrology of nanoparticles in both the liquid and gas phases. This includes the development of new mass-spectrometry and ion-mobility methods to characterize nanoparticles and their reactivity. He also has numerous publications on both phenomenological and atomistic modeling of the thermophysical properties of nanoparticles. He is a recipient of the University of Maryland Outstanding Researcher Award, and the Sinclair Award for Sustained Excellence in Aerosol Research awarded by the American Association for Aerosol Research.

http://www.enme.umd.edu/facstaff/fac-profiles/zachariah.html

Host: Prof. Harsha Chelliah

Speaker: Dr. Keith Moored
Princeton University
Date: Tuesday, April 10, 2012
Time: 4:00 pm

Place: MEC 341
Refreshments at 3:30PM in MEC 341

Abstract:

The use of autonomous underwater and aerial vehicles in law enforcement, marine surveying and military operations has seen enormous growth in the past ten years. However, the full potential of these devices has not yet been realized. Bio-inspired systems may offer the next-generation solutions that are fast, efficient, maneuverable, stealthy and have a broad operational range producing a multi-functional platform. There are two particular features of swimming and flying organisms that are of interest: (1) unsteady locomotion and (2) flexible appendages. This talk will discuss efforts to develop simple but realistic models for unsteady locomotion with flexible propulsors.

First, I will discuss the development of an advanced panel method with viscous corrections to study the physics of unsteady locomotion. As a biological focal point for the modeling, the performance and flow structure produced by batoid rays is examined, revealing how thrust and efficiency are connected to the structure of the wake. Second, the physical mechanisms that lead to efficient propulsion in unsteady flow systems are investigated using the concept of wake resonance theory. The theory is shown to agree with experiments on a three-dimensional bio-inspired propulsor. Furthermore, the theoretical framework identifies the physical conditions that lead to high efficiency, explains the presence of multiple peaks in the efficiency curves, and demonstrates that efficient propulsion can be achieved outside the reverse von Karman vortex street wake pattern.