Colloquium Series Archive

For information on talks prior to Spring 2012, please visit the Colloquium Series Archive links found in the left column of this page.

Spring 2012

January 20, 2012
"The Multi-faceted Physics of General Relativistic Compact Objects" by Dr. Gregory Comer, St. Louis University
3:10 pm
Franklin Miller, Jr. Lecture Hall (RBH 109)
Dr. Comer is a member of the Department of Physics & Center for Fluids at All Scales, College of Arts and Sciences, Saint Louis University. Abstract: When modeling a physical system, theorists must find the nexus between descriptions that have so many simplifying assumptions that predictions are basically empty, and those that are so saturated with detail that insight is impossible to extract. Locating this bond is perhaps the single most important goal for modeling compact objects. The most studied, other than black holes, are neutron stars (which were first detected as pulsars). They are as massive as the Sun, yet small---about 20 kms---and as such require general relativistic gravity and dynamics. They are believed to have a crust, with increasingly neutron-rich nuclei---forming exotic, so-called "pasta" shapes---toward the bottom. Flowing through these nuclei are additional neutrons in a superfluid state. Just below the crust the neutron superfluid no doubt coexists with a conglomerate of superconducting protons and highly degenerate electrons (and maybe muons at higher densities). Deep inside, there are many possibilities, such as deconfined quarks in a color-flavored-locked, superconducting state. In this talk, we will discuss an intense, international effort to model compact stars (since "neutron" is clearly a misnomer). Reception to follow.

January 27, 2012
"Frontiers in High Resolution Ocean Modeling" by Dr. Brian Arbic, University of Michigan
3:10 pm
Franklin Miller, Jr. Lecture Hall (RBH 109)
Dr. Arbic is a member of the Department of Earth and Environmental Sciences, University of Michigan. Abstract: After a brief overview of the field of physical oceanography, including a brief discussion of some outstanding questions in the field, some observational techniques used in the field, and some general discussions of numerical ocean models, I will discuss recent work with US Navy colleagues on incorporating tides into their high resolution ocean forecast models. Reception to follow.

February 3, 2012
"Hot Showers and Nanobots," by Aaron Santos
3:10 pm
Hayes Hall 109 (Franklin Miller Jr. Lecture Hall)
Dr. Santos is a visiting assistant professor in the Department of Physics and Astronomy, Oberlin College. Abstract: Statistical physics is used to study a wide variety of physical phenomena. Ferromagnetism, liquid-gas transitions, the splitting of oil-water mixtures, and DNA melting can all be described using similar lattice-based models. In this talk, Santos will describe how statistical physics and computer simulations can be used to study a simple model of nanoparticle assembly. If experimentally achievable, this work would represent a step toward assembling arbitrarily shaped nanostructures. Reception to follow.

February 10, 2012
"Scanned Laser Beam Projectors, and Life Outside the Ivory Tower ," by Scott Woltman of MicroVision
3:10 pm
Hayes Hall 109
Abstract: Scott Woltman, a systems engineer, will present on MicroVision's patented PicoP(R) Display Engine technology. For years, MicroVision has developed a laser-based scanned beam pico projector for mobile display applications and is in the process of bringing its second generation product to market. Woltman will discuss the applications of MicroVision's PicoP(R) technology and the core opto-mechanical engine at the heart of MicroVision's display engine. Woltman, a Ph.D., will also talk about his journey from being a physics student to playing a pivotal role as an engineer in a high-technology company. Reception to follow.

February 17, 2012
"Modeling Nature's Nano-Machines," by Riina Tehver
3:10 pm
Hayes Hall 109
Abstract: Biological cells are complex non-equilibrium systems that can grow, move around, and divide. These tasks are typically accomplished with the aid of proteins that can be thought of as nano-machines. Just like their man-made analogues, these proteins consume fuel and undergo cyclical changes that ultimately result in mechanical work. During this talk Dr. Tehver will discuss our current understanding of these machines and the theoretical and computational models that allow us to investigate the connection between the structures of these proteins, their dynamics, and how to connect that to their function. Riina Tehver is an assistant professor in the Department of Physics and Astronomy at Denison University. Reception to follow.

February 24, 2012
"Radar Tracking of Multi-Target Complexes Using Hough Transforms," by Charles Meins Jr., MIT Lincoln Labs
3:10 pm
Hayes Hall 109
Abstract: An important function for a fire control radar within a ballistic missile defense system consists of the simultaneous tracking of multiple objects in a missile complex. A challenging tracking scenario is encountered when dense clusters of targets are viewed at large stand-off ranges. In this case, multiple target detections are found within a single radar beam. Because such highly populated complexes are not resolved in angle (azimuth, elevation), separation of the individual objects must rely on the use of wideband waveforms with good range resolution. A multi-object tracking algorithm suitable for real-time implementation has been designed to exploit range-only correlations. Good track initiation efficiency is achieved through the use of short radar observation times combined with applications of Hough transforms. Tracking filters are subsequently used to update all existing tracks with metrics and signature histories. A brief description of the algorithm is presented with focus on the specific tracking techniques appropriate for dense clusters of slowly separating objects on ballistic trajectories. Reception to follow.

March 23, 2012
Senior Exercise Talk by Carolyn Watts and Charles Ewel
3:10 pm
Hayes Hall 109
Please join us for the following Senior Exercise talks. Carolyn Watts Title: "Quantum Dots" Abstract: Quantum dots exhibit many unique optical and electrical properties which differ from those of the corresponding bulk material. They are confined in all three spatial dimensions and have a diameter ranging from 2-10 nanometers. The wavelength of the light coming from the quantum dot depends not on the quantum dot's material, but on its size and shape. Therefore, using only one material, we are able to produce quantum dots which emit all of the possible colors simply by changing their size. The ability to control the color emitted by the quantum dots makes them very useful. They are being used to detect cancer and Alzheimer's disease in their early stages, they are making less expensive and more efficient solar panels possible, and in the future they could even lead to foldable TVs. Charles Ewel Title: "Planck Scale and Fundamental Length" Abstract: In 1889, Max Planck proposed a system of measurement using as units the three most fundamental constants in physics: c, h, and G. In this talk, we'll discuss the Planck length, a tiny distance that has been hypothesized to be the minimum uncertainty with which the position of a particle can be measured. As hard experimental evidence confirming this is impossible to obtain with present technology, a series of thought-experiments designed to heuristically show that the Planck length is the smallest measurable length will be presented, and the implications of this possibility will be explored. A reception will follow the talks.

March 30, 2012
Senior Exercise talk by Daniel Rooker
3:10 pm
Franklin Miller, Jr. Lecture Hall (Hayes 109)
Please join us for Mr. Rooker's senior exercise talk. Titles and Abstracts coming soon! Reception to follow.

March 30, 2012
"A Field Guide to the Large Hadron Collider," by Ethan T. Neil of Fermilab
3:10 pm
Hayes Hall 109
Ethan T. Neil, a research associate in the theoretical physics group at Fermilab, will speak as part of the Physics Colloquium Series. Abstract: Proton-proton collisions at the Large Hadron Collider, which will occur in 2012 at record-setting energies, will allow us an unprecedented view of the structure of matter at very small distances. I will discuss the tools and methods used, both experimental and theoretical, in order to understand the collisions and search for signatures of new physics. I will also review several proposed models for new physics and their corresponding signals, including supersymmetry, dark matter, and large extra dimensions. Reception to follow.

April 6, 2012
Senior Exercise Presentations by Daniel Rooker, '12, and Ryan Talk, '12
3:10 pm
Franklin Miller, Jr. Lecture Hall (Hayes 109)
Please join us for senior exercise presentations by Daniel Rooker and Ryan Talk. Daniel Rooker, '12 Title: "A Tale of Two Exponentials" Abstract: Built for the World Exposition in 1889 in Paris, France, the Eiffel Tower stands as a reminder of the French Revolution in Europe a century prior. Over the years, there have been attempts to mathematically model the Eiffel Tower and we will explore a recent "successful" equation developed by Professor Patrick D. Weidman (University of Colorado, Boulder) and Professor Iosif Pinelis (Michigan Technological University). Ryan Talk, '12 Title: "Stepper Motors" Abstract: Stepper motors are used in many machines that utilize precise positioning mechanisms. In my talk I will be explaining how the stepper motors work and the purpose of the circuitry. Reception to follow.

April 9, 2012
"Imaging in the Infrared (and Ultraviolet)" by Dr. Charles M. Falco, University of Arizona
3:10 pm
Franklin Miller, Jr. Lecture Hall (RBH 109)
Dr. Falco is Chair of Condensed Matter Physics, Professor of Optical Sciences and Professor of Physics at the University of Arizona. Abstract: Many common pigments are partially transparent to near infrared (IR) light, making it possible to use IR-sensitive imaging sensors to capture information from surfaces covered by several tens of micrometers of such pigments. Because of this, "IR reflectograms" have been made of paintings since the late 1960s, revealing important aspects of many works of art that are not observable in the visible. However, the high cost and specialized nature of available cameras have limited such studies to a very small fraction of the works of art that could be usefully studied in the IR. After a brief introduction to IR reflectography, I will describe the characteristics of a high resolution imaging system that has made it possible to obtain IR reflectograms of works of art in situ with standard museum lighting. I will illustrate its capabilities with IR and visible images of various types of art in museums on three continents. I also will describe an ultraviolet (UV) camera, and multispectral sensor system we are working on for a proposed mission to Jupiter at the end of the decade. Reception to follow.

April 10, 2012
Phi Beta Kappa Public Lecture: "The Science of Optics, the History of Art," by Charles M. Falco
7:30 pm
Community Foundation Theater, Gund Gallery
Dr. Falco is chair of condensed matter physics, professor of optical sciences, and professor of physics at the University of Arizona. Abstract: In this talk I show a wealth of evidence, which the artist David Hockney and I discovered, that demonstrates optical instruments were in use--by artists, not scientists--nearly 200 years earlier than commonly thought possible. These discoveries account for the remarkable but previously unexplained transformation in the reality of portraits that occurred early in the fifteenth century. Reception to follow.

April 13, 2012
"2π Is Not Zero (But 4π Is)" by Dr. Benjamin Schumacher, Kenyon College, Department of Physics
3:10 pm
Franklin Miller, Jr. Lecture Hall (RBH 109)
Abstract: If you rotate a geometrical shape by 2π radians (360 degrees) about any axis, you wind up with exactly the same shape, just as if you did no rotation at all. However, this simple fact -- seemingly obvious -- is actually not true for quantum particles with spin! We will explore the subtle difference that a 2π rotation makes -- how there can be a difference at all, and why that difference is one of the most important ideas in all of physics. (Though we will grapple with profound concepts of matter and geometry, this talk should be accessible to anyone who lives in three-dimensional space.) Reception to follow.

April 20, 2012
Senior Exercise Talks by Langston Vonderheide and Ian Bakk
3:10 pm
Franklin Miller, Jr. Lecture Hall (Hayes 109)
Please join us for Mr. Vonderheide's and Mr. Bakk's senior exercise talks. Ian Bakk Title: "Understanding Raman Scattering Enhancement through Surface Plasma Waves" Abstract: Raman scattering occurs in 1 out of every 10⁸ molecules, several orders of magnitude less than Rayleigh scattering or competing fluorescence. Raman scattering gives unique chemical "fingerprints" of the molecules it excites, making it a useful tool for detection; however, unaided Raman is too weak for many situations and requires a careful experimental set-up. Surface Enhanced Raman Scattering (SERS) can amplify Raman effects by several orders of magnitude through surface plasma waves. By examining the interaction between electromagnetic waves and plasmas and the experimental techniques needed, I will explain the excitation of surface plasma waves and their importance for SERS. Langston Vonderheide Title: "RFID: Near and Far" Abstract: Radio Frequency Identification has become ubiquitous in modern life, from anti-theft devices in retail, to livestock and wildlife tracking. In this talk we'll be exploring the relationship between RFID tag range and operating frequency and the near and far field representations of the electric and magnetic field. Reception to follow.

April 27, 2012
"Use of Computational Methods for the Design of Gas Turbines," by Dipankar Dua, Rolls-Royce Energy Systems
3:10 pm
Hayes Hall 109
Abstract: Of all the combustion power technologies currently available, gas turbines provide the highest power to weight ratio and facilitate the most efficient and cleanest mode of power generation. Since Norwegian Aegidius Elling invented the world's first gas turbine in 1903, this technology has steadily advanced and continues to evolve. In an effort to increase performance and efficiencies, coupled with a reduction in emissions, weight, and cost, the latest gas turbine technologies push the boundaries of engineering design envelopes. This talk will provide an overview of some of the multi-physics and multi-disciplinary analytical/computational techniques currently utilized by engineers to model, simulate, integrate, and validate gas turbine designs before their fabrication phase.

May 4, 2012
"Mechanix Illustrated," by Professor Emeritus of Physics Thomas B. Greenslade Jr.
3:10 pm
Hayes Hall 109
Abstract: This talk starts with the humble inclined plane, and it is all downhill from there! First, there is a detour up Mt. Washington in New Hampshire and a trip in a canal boat from the Shropshire Union Canal in England down to the nearby Severn River before we investigate how a body can roll uphill. The tour then goes to the Isle of Man in the Irish Sea where we will see Lady Isabella going round and round, and then to the province of North Holland to see water traveling uphill, aided by the work of an ancient Greek. We continue on to power dams in Washington State, observe water transport at the Isthmus of Panama, and see the Lockport Five on the Erie Canal. Naturally we will want to see how the land was cleared for the Erie Canal, and the talk ends with beats on sidewalks, roads, and paper. The talk is lavishly illustrated with the modern form of lantern slides. Reception to follow.