REU Project Descriptions
Click on the project name for a more detailed description of the project
New project in astronomy posted February 2
Project Name: Chaotic Mixing and Propagating Reaction
Fronts
Project Mentor: Tom Solomon
Project Code: (THS-1)
In a forest fire, the dividing line between burned and unburned trees is called a front. The motion of this front determines how the fire spreads through the forest. Similar front dynamics characterize the spreading of a disease in society, as well as numerous chemical processing applications, biological processes in cells and developing embryos, and plasmas in fusion reactors. We are currently conducting experiments that explore how the motion of fronts is affected by fluid mixing, e.g., forced flows in a chemical processor, winds in a forest fire, or the motion of people in society while a disease spreads. Table-top experiments using a simple chemical reaction (the well-known Belousov-Zhabotinsky reaction) focus on how fronts are affected by simple flow patterns -- vortices (whirlpools) and jets. We are currently testing theories of "burning invariant manifolds" that describe front behavior in two-dimensional flows, and we anticipate extending these studies to three-dimensional flows this summer.
There is a lot of "hands-on" work involved in this project, including the designing, building and testing of the experimental apparatus, mixing chemicals for the reaction, and doing numerous experimental data runs. The experimental work also involves a substantial amount of computer-aided image analysis, almost exclusively on Linux workstations running a program called IDL. We also frequently conduct numerical simulations of the phenomena, also with IDL. Although experience in computer analysis is useful, it is not required as long as the student involved is willing and eager to learn IDL.
Project Name:
Investigating the Impact of Atmospheric Aerosols on Cloud Formation
Project Mentor: Tim Raymond
Project Code: (TMR-1)
One of the largest uncertainties in global climate models is planetary cloud cover. Clouds have a critical effect on both solar and terrestrial radiation balances and ultimately on climate. Whether or not a cloud will form is dependent on the interactions between temperature, water vapor, and the properties of cloud condensation nuclei (CCN) particles. These particles, called atmospheric aerosols when suspended in the gas phase, are found throughout the Earth's atmosphere from urban centers to the remote arctic. Atmospheric aerosols range in sizes from a few nanometers up to several microns or even millimeters for some ashes/dusts but the most important size range for cloud formation is about 20-200 nanometers in diameter.
In our experimental laboratory, we have the ability to generate and measure aerosols of specific chemical composition and size and then subject them to increasing relative humidities including those experienced in clouds (over 100% RH). This research project will involve using sophisticated instruments to generate, manipulate, measure, and image a range of simulated and real atmospheric aerosols in order to gain a better understanding of cloud formation.
Project Name: Infrared Spectra of Galactic Nuclei
Project Mentor: Jack Gallimore
Project Code: (JFG-1)
Galaxies show varying degrees of star-formation and nuclear activity. Star-formation is the process by which dusty, molecular clouds collapse to form clusters of stars. Nuclear activity refers to the fueling of an accretion disk surrounding a massive black hole at the galaxy's center. The accretion disk is commonly obscured by a ring of dusty, molecular clouds. A significant fraction of the visible-UV-X-ray energy produced by star-formation and nuclear activity is therefore absorbed in dusty interstellar clouds, and these clouds warm up and re-radiate the incident energy in the infrared.
This project is a study of the infrared spectrum of galaxy nuclei as measured by the Spitzer Space Telescope. The primary goals are (1) to understand the nature of the colder dust and gas associated with nuclear activity and (2) to measure the relative contribution of star-formation and nuclear activity to the energy budget of each galaxy. The main activity will be fitting theoretical models for infrared radiation to observed spectra and further to apply constraints based on photometry and spectroscopy at other wavebands. Other activities will include searches for published or publicly available archival data to supplement the Spitzer data already in hand.
Basic familiarity with computers is necessary, and experience with the Linux/Unix operating system would be beneficial. Most of the codes currently revolve around Python scripting and use of the Numpy, Scipy, and PyMC packages. (Previous experience with Python is not expected.)
Project Name: Discovering Planetary-mass Brown Dwarfs
Project Mentor: Katelyn Allers
Project Code: (KNA-1)
Brown dwarfs (objects with masses too low to sustain hydrogen burning) are the bridge between planets and stars. Young brown dwarfs are particularly exciting as objects with masses in the range of extrasolar planets are within the reach of direct observations in the near and mid-infrared. This project involves reducing and analyzing images of star-forming regions to identify new planetary-mass brown dwarfs. This project may involve planning and executing observations. Familiarity with IDL or Python is desirable but not required.
Project Name: Non-equilibrium Thermodynamics and Quantum Statistics
Project Mentor: Martin Ligare
Project Code: (MKL-1)
Most introductory thermodynamics is limited to the study of systems in equilibrium. Recently there have been many advances in the field of classical non-equilibrium thermodynamics, and in this project we will generalize these advances to quantum systems of identical particles to study how the bosonic or fermionic nature of the particles in the system effects the thermodynamics.
Project Name: Theoretical Quantum Optics
Project Mentor: Martin Ligare
Project Code: (MKL-2)
Recent observations of anomalous light propagation include light that refracts "the wrong way" in so-called negative-index materials, "superluminal" light that appears to travel faster than the speed of light c, and ultraslow light. I have investigated theoretical models in which the electromagnetic field and the medium are both treated in a fully quantum mechanical manner in order to understand these anomalous effects at the level of a single photon. Topics for investigation in the summer of 2015 might include the following:
- Photon transport in metamedia with negative index of refraction
- Negative group velocities in media with gain
- Photon propagation in evanescent waves
- Photon transport and localization in disordered media
This project will involve theoretical calculations and work with a computer algebra system. Applicants for this project should have completed a quantum mechanics course at the junior/senior level.
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Last updated January 23, 2014
