Third year report

Third year of the Chicago Chile Exchange

April 25, 2006

Annual reports from years 1, 2, 3, 4, 5, 6, 7, 8, 9, 10

Since May 2005 five University of Chicago students did internships in Chile, eight Chilean students spent the winter quarter in Chicago internships and seven Chicago students are preparing to do internships in Chile this summer. The coordinating faculty in Chile has undergone a smooth changover, and the program hosted one of the co-ordinators in Chicago in November 2005. Some administrative improvements and changes in funding the Chicago students were adopted.

Chicago students in Chile June-August 2005

Colin McFaul, a graduating physics major, worked with Prof. Nicolas Mujica. His project concerned the experimental study of acoustic interactions in two-phase media. He studied the collective behavior of solid magnetic particles immersed in water, excited by a strong acoustic wave. The particles are expected to move in response to the radiation pressure. The observed motion was small. They concluded that replacing the water with air would work better.
Matthew O"Meara, then an entering third-year physics major worked with Prof. Mujica on oscillons. These are localized vibration modes of a liquid surface excited by strong but uniform shaking of the liquid. Matthew mastered the technique to generate the oscillons near the boundaries of the surface and captured some intriguing qualitative behavior with a high-speed camera. His observations will serve as a basis for future studies in Mujica's lab.
Joe Bolte was a graduating senior. He worked with Prof. Felipe Barra at the University of Chile on a recent prediction about thermodynamic fluctuations. This prediction, called the Jarzinski theorem, predicts transient energy flows between a system and its environment. A one-particle gas collides with an advancing wall, and the fluctuating mechanical work done by the gas on the wall is calculated and compared to the prediction of the Jarzinski theorem. They verified the theorem in a context that was different from previous checks.
Nathan Krapf was a graduating physics major. He is worked with a postdoc named Valerie Vidal in Francisco Melo's group. They studied the mechanical basis for an intriguing geophysical effect. Bursting bubbles of lava may emit resonant sounds as they burst. Melo and Vidal have devised a small-scale model which reproduces this phenomenon using viscoelastic liquids. Nathan studied the viscoelastic conditions needed for the effect to occur.
Carolyn Brown was an entering third-year physics major. She worked with Prof. Raul Labbe, Enrique Cerda and Sergio Rica at the University of Chile. Her work concerns the nonlinear interaction of vibrational modes in a stretched wire experimentally and numerically. There is regime in which energy is transmitted from the lowest wavenumbers to somewhat higher ones and thence to yet higher ones, forming an energy cascade of the type proposed by Kolmogorov in turbulence. Carolyn got some preliminary data that showed the expected form, and it laid the groundwork for further study.
Results from Chicago-to-Chile program 2005
In conversations with the students upon their return, they found the experience worthwhile and useful, but they were dis-satisfied with some aspects of their visit. First, their living arrangements gave them limited interaction with Chileans. They found themselves staying in an isolated group. Second, they were disappointed with the slow startup of their projects. Often they had to wait for weeks while equipment or material was ready for them to work with.
In conversations with the professors, the professors were satisfied with the experience. They thought they gave significant pedagogical benefit and received some degree of benefit to their research. Some of the Chicago students were less advanced than the Chilean students they sent us, and they anticipated a greater degree of independence and sophistication.
This summer the proposed projects have been better attuned to the student's level. We also plan different housing arrangements in apartments in the city rather than in a foreign-student house. We also plan a longer ten-week internship.
Funding changes
Under the program the Chileans are supposed to provide local support for each student. However the number of students and the longer-than-anticipated visits left them short of funds. Happily another international exchange program, the Consortium for the Americas, headed by Nitant Kenkre of the University of New Mexico, was able to cover the shortfall. These funds were paid to the University of Chicago, who then gave the money to the students in the form of travel advances paid against living expenses.

Chileans in Chicago: January-March 2006

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Changes and lessons learned

clerical errors. Last year's Chilean students suffered from errors in enrolling them as special students and in enrolling them with the payroll and social security offices. This year a new administrator Pegg Anderson was put in charge of these matters, and her vigilance and pro-active action virtually eliminated these problems.
longer terms. Last year's students had too little time to do their projects because they arrived late. This year we made arrangements for them to arrive before the beginning of the term. This significantly improved their ability to do meaningful projects.
visa delays. Because of delays in identifying the students and in matching them with supervisors, the students were unable to start their visa applications until 2-3 weeks before their scheduled departure. Some of the visas were granted only at the last minute. We shall try to initiate the process about a month earlier this year.

Chicagoans in Chile, June-September 2006

Luka Pocivavsek is a second-year graduate student in a joint MD-PhD program. His PhD research concerns buckling in lipid monolayers at an air-water interface. In Chile he will deepen his background on elastic deformations by studying the elastic swelling that occurs during the opening of a pollen grain in collaboration with Prof. Enrique Cerda of the University of Santiago.
Katy Huff is an entering third year undergraduate. She will work in Prof. Nicolas Mujica's lab at the University of Chile on acoustics of multiphase systems like dispersions.
Adam Weis will work with Rodrigo Soto's simulations of flowing suspensions at the University of Chile. In the process of sedimenting, these suspensions spontaneously develop dense and sparse regions. Adam will investigate whether small additional perturbations of the density propagate diffusively or in some active way.
Charles Greenberg is an entering third year student in physics. He will do a biophysics experiment in the group of Prof. Francisco Melo at the University of Santiago. He will look at how the growth of a nerve-cell axon is influenced by external forces exerted by a micropipet.
Jessica Millar is an entering third-year physics major at Chicago. She will work in the lab of Prof. Nicolas Mujica at the University of Chile. Her direct supervisor is Carlos Orellana, a masters-degree student. Carlos' experiment is a planar vertical channel in containing granular material violently blown upwards by a blast of air from beneath and then followed with a fast camera. The spontaneous pattern formations that are observed as the material relaxes will be examined.
Mike LeBlanc is an entering third-year student doing a major in physics and math. He will work with a Eugenio Hamm, a research scientist in Prof. Melo's lab. The subject of the project is the tearing of a thin elastic sheet. Recent studies showed that the migration of a tear in a strip of paper is influenced by the presence of the tear on the other side of the strip. LeBlanc's project will study the influence when the tear approaches the edge of the sheet.
Two additional students enrolled in the program and had decided on projects with Chilean professors. They later withdrew from the program because unforseen events made them change their plans. It was not possible to find suitable replacements for them in the time remaining.
Funding changes
In order to enable the Chileans to support this large number of Chileans for a full ten weeks, we have again arranged to supplement their expenses via a travel advance. Last year this was made possible by a payment from the Consortium of the Americas, as stated above. This year, it is being funded by the Chicago-Chile materials collaboration itself. We plan to continue this supplement next year as well.

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