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Chicago students in Chile 2010

Seven University of Chicago students did internships in summer, 2010. 
UC students on hike Alto el Naranjo hosted by Prof. Enrique Cerda.  Clockwise from left Ned Lieb, David Blair, Trent German, Kyle Felker (hidden) and Paul Wyatt.  Picture taker Mike Baumer and Nikita Nangia not shown

Mike BaumerBaumerExp

Mike's project was to re-build a hydrodyanamic instability studied extensively in Prof. Nicolas Mujica's group at the Universidad de Chile.  At the right you cee a vertical cylinder with a rotating cylinder in the middle.  The rapid rotation of the cylinder makes the water surface spontaneously tilt.  
The experiment needs a vibration-free drive and precise measurements of the water surface profile as it swirls around.  Michael's work improved the mechanical and electrical workings of the experiment greatly.  After these improvements he had time to explore the rocking rate of the tilted surface vs the rotation rate.

Mike's final report

David BlairBernalIndenter

    David worked with Prof. Roberto Bernal at USACH to develop a new measurement tool: the micro-indenter.  It uses piezo controllers to make tiny, precise indentations in a test surface and measure the associated forces.  To work correctly the machine needs a control system that senses the forces, drives the displacments and operate a microsope camera. 

Kyle Felker

    Kyle studied Shear-like Fluidization of a horizontally vibrated granular deposit via simulation under the supervision of Prof. Rodrigo Soto. A picture of the simulation with the free grains above and a solid floor below is shown at left.  As in the case of granular avalanche, a horizontally shaken box of sand releases stress through gradual surface fluidization.   He found that the shear band (colored region in picture at right indicating region of moving grains) advances exponentially with increasing shaking strength (horizontal axis of right-hand picture)---even faster for longer driving periods. The shear band seemingly slides (no rolling) over the bottom layers.

Trent German


    Trent worked in the lab of Raul Cordero.  His subject was the "Cuticulas" seen at the left, peeled from the skin of fruits.  The task was to measure their strength, a measure of the fruit's robustness, using the pulling apparatus at right.  He found a way to cut precise sections of the cuticulas and showed his colleagues how to manipulate them without  damage.  Using the machine he measured the Young's  modulus and monitored their thickness with a laser interferometer.

Ned Lieb

Ned's project concerned the strengthening properties of nanoparticle in the lab of Prof. Maritza Paez at USACH.  During his stay he was working on preparing silanol films modified with silver nanoparticles and determining their  mechanical properties, founding relevant results associated with the influence of incorporating the nanomodifiers

Nikita Nangia

Can you make a sheet of paper tear in a desired shape by perforating it?   This is the question posed by Prof. Eugenio Hamm at USACH.  They have a computer-controlled perforator that can punch lines in any desired pattern.  Nikita found that if you make a line of parallel slits, the shape of the tear is scalloped.  Nikita found that for a given initial separation w of the perforated lines, near criticality, the angle of propagation of the cracks approached the angle of a simple tearing experiment corresponding to the same instantaneous value of w (local width of the strip).

Paul Wyatt

wyattWyatt setup

    Paul  worked on chaos in surface waves  in the  lab of Prof. Claudio Falcon at the Universidad de Chile.   Paul was supposed to develop an experiment on waves in a  trough with an irregular bottom.   Paul, with the help of another intern, designed an new experiment with greater length, depth, robustness.  It is shown at right.  the irregular bottom is made by the black blocks on the bottom of the trough.  Capacitive sensors record the height of the waves generated at one end of the trough Paul upgraded these sensors and resonant circuits used for data acquisition.