Colloquium Spring 2011

 

 

January 24
Essentials of Creativity, Discovery & Invention
Behrok Khoshnevis
Industrial and Systems Engineering
USC

Abstract

Great scientific discoveries and inventions leading to technological systems, processes and products are largely based on the exercise of inventive thinking and not on routine procedures such as methodical analysis and optimization. Science and engineering research could conservatively aim at making marginal improvements to the state-of-the-art in the chosen domain, or it may be based on original and novel ideas which potentially lead to breakthrough impacts through discovery of new frontiers and creation of great inventions. Creative professionals use inventive, non-routine approaches and in most instances their creations clearly stand out. Inventive thinking and problem solving enrich professional life and bring prosperity to organizations and society. Contrary to common believe creativity in science and technology, i.e., the ability to discover and invent, can be acquired and enhanced.

Essentials of inventive thinking and technological creativity that could lead to breakthrough scientific findings and engineering designs will be presented and several realistic case studies reflecting the speaker's own experiences in invention and technology development will be discussed.

January 31
No Colloquium - Canceled

February 7
Three-Dimensional Patterning of Porous Materials Using Vapor Phase Polymerization
Malancha Gupta
Chemical Engineering and Materials Science
USC

Abstract

The chemical vapor deposition of polymer films eliminates the need for organic solvents and thereby offers a safer and cleaner alternative to liquid-phase polymer processing. The initiated chemical vapor deposition (iCVD) is a vapor-phase free radical polymerization technique that can be used to produce films that exhibit a wide range of properties such as hydrophobicity, hydrophilicity, and responsiveness to heat, pH, and light. Unlike most vapor deposition techniques, the iCVD process is not a line-of-sight process and therefore it can be used to uniformly coat substrates that have complex three-dimensional shapes such as trenches, pores, and fibers. Although iCVD has been used to pattern polymers onto flat surfaces using colloidal lithography, electron-beam lithography, and capillary force lithography, the ability to use iCVD to pattern porous materials such as paper-based microfluidic devices has yet to be demonstrated. This talk will discuss two new iCVD methods that can be used to pattern three-dimensional porous materials with functional polymers.

February 14
No Colloquium - Canceled 

February 21
President's Day - University Holiday

February 28
Anthony Leggett
University of Illinois at Urbana-Champaign

Abstract

When a high-energy particle such as a gamma-ray, neutron or cosmic-ray muon is incident on an ultra-low temperature system such as superfluid 3He, it may heat a small region of the liquid to temperatures of the order of a thousand times the ambient one. The recovery from this very unusual situation, and it s possible consequences for the nucleation of first-order phase transitions, topological singularities etc., provide a fascinating challenge to theory. I discuss some of these problems in the context of the Stanford experimnets on nucleation of the 3He B phase by radiation and the recent neutron experiments on 3He which are designed to mimic the behavior of the early Universe.

March 7
Scientific and Computational Challenges of the Fusion Simulation Program (FSP)
William M. Tang
Chief Scientist
Princeton Plasma Physics Laboratory

Abstract

This presentation will highlight the scientific and computational challenges facing the Fusion Energy Sciences research area. Major progress in magnetic fusion research has led to ITER – a multi-billion dollar burning plasma experiment supported by seven governments (EU, Japan, US, China, Korea, Russia, and India) representing over half of the world’s population. Currently under construction in Cadarache, France, it is designed to produce 500 million Watts of heat from fusion reactions for over 400 seconds with gain exceeding 10 – thereby demonstrating the scientific and technical feasibility of magnetic fusion energy. It is a truly dramatic step forward in that the fusion fuel will be sustained at high temperature by the fusion reactions themselves. While many of the technologies used in ITER will be the same as those required in an actual demonstration power plant (DEMO), further science and technology is needed to achieve the 2500 MW of continuous power with a gain of 25 in a device of similar size and field. Advanced computations in tandem with experiment and theory are needed to harvest the scientific knowledge from ITER and leverage its results. The associated research demands computational tools and techniques that aid the acquisition of the scientific understanding needed to develop predictive models which can prove superior to extrapolations of experimental results. Reliable modeling capabilities in Fusion Energy Sciences are expected to require computing resources at the petascale (1015 floating point operations per second) range and beyond to address ITER burning plasma issues. This provides the key motivation for the Fusion Simulation Program (FSP) – a new U.S. Department of Energy initiative supported by its Offices of Fusion Energy Science and Advanced Scientific Computing Research -- that is currently in the program definition/planning phase. The primary objective of the FSP is to enable scientific discovery of important new plasma phenomena. This requires developing a predictive integrated simulation capability for magnetically-confined fusion plasmas that are properly validated against experiments in regimes relevant for producing practical fusion energy. Substantive progress on answering the outstanding scientific questions in the field will drive the FSP toward its ultimate goal of developing the ability to predict the behaviour of plasma discharges in toroidal magnetic fusion devices with high physics fidelity on all relevant time and space scales. From a computational perspective, this will demand computing resources in the petascale range and beyond together with the associated multi-core algorithmic formulation needed to address burning plasma issues relevant to ITER. Even more powerful supercomputers at the “exascale” (1018 floating point operations per second) range and beyond will be needed to meet the future challenges of designing a demonstration fusion reactor (DEMO). Analogous to other major applied physics modelling projects, plasma physicists will need to closely collaborate with computer scientists and applied mathematicians to develop advanced software that is validated against experimental data from tokamaks around the world. Specific examples of expected advances which are needed to enable such a comprehensive integrated modelling capability and possible “co-design” approaches will be discussed.

March 14
Spring Break

March 21
Mechanical Mysteries of Bio-Membranes
Professor Raghuveer Parthasarathy
Parthasarathy Lab
Department of Physics
University of Oregon

Abstract

The membranes that form the boundaries of every cell and every organelle inside every cell are remarkable materials – flexible, two-dimensional, self-assembled fluids. I'll describe two projects that explore the physical properties of membranes and that illuminate their role in guiding biological function. One relates to the trafficking of cargo in cells, which involves dramatic changes in membrane shape whose physical underpinnings remain poorly understood. Measuring the stiffness of membranes by tugging on them with optical tweezers, we’ve found that a key trafficking protein can drastically alter membrane rigidity, suggesting a new mechanistic picture for intracellular transport. The other project relates to the fluidity of membranes – phenomenologically well-established yet fundamentally poorly characterized – which we probe by examining the Brownian motion of membrane-anchored nanoparticles. Surprisingly, we have discovered that membranes are not simple “Newtonian” fluids, like water, but rather are viscoelastic – two-dimensional analogues of the entertaining grade-school staple of corn-starch and water.

March 28
Frustrated quantum magnetism and superconductivity
Patrick Lee
Department of Physics
MIT

Abstract

It has long been expected theoretically that quantum fluctuations may destroy anti-ferromagnetic order in certain "frustrated" systems, but it is only in the past few years that experimental systems showing this behavior have been discovered. Indeed these systems show signs of predicted "emergent' new particles such as neutral spin 1/2 fermionic excitations called spinons. I shall review the recent development and discuss possible connection to superconductivity.

April 4
Mysteries in cluster suburbia: new insights from radio observations
Marcus Brüggen
Jacobs University

Abstract

Galaxy clusters form through a sequence of mergers of smaller clusters and groups. Shocks that occur during cluster mergers accelerate particles to relativistic energies, similar to what happens in supernova remnants. In the presence of magnetic fields, these particles emit synchrotron radiation and may form so-called radio relics. New observations show that diffusive shock acceleration operates on scales much larger than in supernova remnants and that shocks in galaxy clusters are capable of producing extremely energetic cosmic rays. However, our observations also challenge models of shock acceleration and magnetogenesis in galaxy clusters. New low-frequency radio observations will lead to new insights into the physics of extreme plasmas as they are found in cluster outskirts. Finally, I will report on first observations with an innovative radio interferometer, LOFAR, that consists of antennae spread across Europe.

April 11
Atomistic simulations of early stages of oxidation and ultra-thin oxide growth on metal and metal alloy surfaces
Subramanian Sankaranarayanan
Assistant Scientist
Center for Nanoscale Materials
Argonne National Laboratory

Abstract

Synthesis of ultra-thin oxide films with controlled functional properties is of tremendous technological importance. These applications include but are not limited to tunneling barriers in electronic devices, templates for model catalysts and passivation layers to protect against corrosion. The ability to tailor the material characteristics by controlling the complex oxide composition grown on alloy substrates is one of the crucial factors determining their applicability.
One of the outstanding problems in oxide synthesis has been the ability to synthesize high quality ultra-thin films at room temperature. To-date, this has remained elusive due to several factors such as phase stability, segregation, micro-mixing and differing growth kinetics of alloying constituents. Atomistic simulations such as molecular dynamics are used to explore athermal routes such as applied electric fields to control oxide density, oxide stoichiometry and oxide composition in case of alloys at room temperature. Insights into the microscopic processes involved in early stages of oxidation of metal and alloy substrates are provided by the atomistic models employing dynamic charge transfer between atoms. Using representative examples of ultra-thin oxide growth on Al, Ni, Zr and their alloys, the simulations are used to demonstrate a pathway to athermally tune oxygen concentration in near-surface regions that is of great importance to contemporary problems in complex oxides ranging from strongly correlated phenomena to catalysis.

April 18
Exploring Dark Matter and Dark Energy with Weak Gravitational Lensing
Jason Rhodes
Research Scientist
Jet Propulsion Laboratory

Abstract

The subtle changes in the observed shapes of background galaxies by foreground dark matter, or weak gravitational lensing, provide tight constraints on the amount and distribution of dark matter in the Universe. The growth of these dark matter structures over cosmic time is governed by interplay between the attractive force of gravity and the repulsive and mysterious dark energy. Together, dark matter and dark energy comprise over 95% of the mass/energy of the Universe but they remain poorly understood; weak lensing has emerged as one of the most promising techniques for understanding the dark sector. We will discuss various future projects that aim to understand the dark sector via weak lensing. These projects include ESA's Euclid mission, NASA's Wide Field Infrared Survey Telescope (WFIRST) and the proposed High Altitude Lensing Observatory (HALO) balloon experiment.

April 25
Nanoplasmonics: The Physics behind the Applications
Mark Stockman
Department of Physics and Astronomy
Georgia State University

Abstract

Nanoplasmonics deals with collective electron dynamics on the surfaces of metal nanostructures, which arises due to excitations called surface plasmons. The surface plasmons localize and concentrate optical energy in nanoscopic regions creating highly enhanced local optical fields. The plasmonic fields are not only highly enhanced, they are also ultrafast: on the femtosecond or even attosecond scale. Fundamentals of plasmonics will be discussed. The properties of the surface plasmons and their local fields are in the foundation of the many real life applications of nanoplasmonics to science, technology, environmental monitoring, biomedicine, and defense. A brief review of some of these applications will be given.

 

 



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