I worked with Prof. Pretorius to learn about numerical methods for solving PDE's whose solutions contain shocks, or discontinuities. These often occur in fluid dynamics, and cannot always be solved accurately with classical finite difference methods since these rely on the assumption of continuity. Finite volume methods, which are based on calculating the flux transfer between computational cells, provide one way of approaching these problems, and in some cases produce results with a relatively high order of convergence. I developed a tutorial that discusses one such method (the Roe solver) and guides the reader through its implementation in a Java program to solve Burger's equation.
Mariela D. Petkova
In summer 2008, I started by taking apart the remains of an old prototype telescope setup on the roof of Jadwin, but my main project was to design a support structure and jack system for the ABS (Atacama B-mode Search) telescope which was being designed and built in the cosmology group to study the polarization of the cosmic microwave background. There was a custom shipping container in the high bay of the physics building which had been modified so that one half of the roof could be removed. My job was to design and build a support structure so that the 1.5 ton telescope sitting on a 1 ton, two-axis motorized base could be transported to the observation site in Chile inside the shipping container and then raised up through the opening in the roof and secured for long term observation. I learned how to use the 3D design software package SolidWorks in order to design a structure from industrial steel framing. I learned to machine in the department machine shop course, and then machined all of the holes and custom fasteners required to assemble the structure. Then I began to assemble the structure inside the shipping container. The structure was seven feet tall and nine feet long and weighted about 1,000 lbs in total, so I assembled it with the help of a small manual forklift. By the end of my internship, the main frame of the structure had been assembled and fitted snugly into the shipping container. I was unable to complete the lifting portion in time. That was completed later by graduate students in the group and machine shop staff.
I am currently (2013) a graduate student at Stanford University in the group of Professor Benjamin Lev, and I am working to build up a new experiment to study novel states of quantum soft matter generated by coupling a Rb BEC to a multimode optical resonator. I have designed and assembled a UHV vacuum chamber to house the experiment and worked on parts of the laser system needed to implement laser cooling to quantum degeneracy.
In summer 2008 I worked on designing feedhorns for use in experiments to measure B-mode polarization of cosmic microwave background (CMB) radiation. The CMB consists of the first observable photons emitted some 400,000 years after the Big Bang and is an invaluable tool for cosmologists as a window into our universe's early history. Although a B-mode (gradient free) signal in the CMB has never been observed, a positive detection would be a robust confirmation of leading cosmological theories where such signals are generically predicted.