Physics Department Seminar

In the summer of 2009, I worked for 10 weeks as part of a Medical Physics team at Wake Forest Baptist Hospital. Our main goal was to come up with a program that would allow for the treatment of cancer with minimal radiation. We used Matlab Fourier Transforms to write a program that would allow us to do proper characterization of geometric uncertainties caused by in-plane motion of the digital flat-panel detector. This is what is known as Tomosynthesis. I studied a new technology called the IBU that does only 2D imaging and we had to write the program to enable it to do 3D volumetric imaging. It is the only one of its kind in North America and one of four in the whole world. I will discuss how my Guilford education prepared me to contribute to this project, as well as how I benefitted from the experience.

I will report on my experiences as part of a ten-week REU summer program at the University of California at Los Angeles. With my mentor Professor Karoly Holczer, we constructed subatomic resolution investigation tools, or Scanning Probe Microscopes (SPM), such as tunneling (STM) and Atomic Force Microscopes (AFM). Position measurement and control is at the heart of every SPM, and I worked on a technique for measuring deflections in a cantilever and tip system in an AFM with up to picometer precision. I will discuss how I benefited from the REU program and hopefully spark interest in students who are thinking about doing a summer research program.

I will report on an experiment carried out at Guilford College in the summer of 2009 that used an electroretinogram (ERG) to measure electrical responses to light from the retinas of adolescent and adult Zebrafish (Danio rerio). This method uses extracellular borosilicate glass electrodes placed inside the cornea to record electrical impulses in response to a flashing LED. We used a 1W LED; flashing with durations of 500 milliseconds set 5 seconds apart. Our results show electrical activity peaking directly after the LED flashes, as well as a smaller peak following the light.

Come to Don and Kembra's house for an evening of food, movies and games. 7-11 pm. Ask Don for directions. (About 3 miles from campus.) Please RSVP with food allergies/preferences.

I will report on observations carried out as part of the ERIRA program with a 40-foot radio telescope at the National Radio Astronomy Observatory in Green Bank, West Virginia in the Summer of 2009. I was part of a small group of students from colleges in NC who were able to map our galaxy, the Milky Way, Using the 40-foot telescope, which collected radio waves around the neutral hydrogen wavelength (~21cm). I will discuss how to collect and analyze the data that results from the scanning of the radio sources. Our results also enabled us to study the changing fading rate of the supernova remnant Cassiopeia A and the rotation curve and mass distribution of the Milky Way.

I will report on the serendipitous detections of thermonuclear (type I) X-ray bursts from the LMXB 4U 0614+091 with a variety of instruments, in particular the 12+ year sky survey by the RXTE All-Sky Monitor. These bursts firmly establish the neutron star character of the compact object in 4U 0614+091 and confirm the assumed optical counterpart. One of the bursts showed a very strong photospheric radius-expansion phase, fixing the distance to the source at 3.2 kpc. I will also point to a challenge posed by these bursts, in that the burst behavior is easier to understand if there is at least an appreciable amount of helium present in the accreted material from the donor star. If the system is an ultra-compact X-ray binary with a CO white-dwarf donor, as has been suggested, this is unexpected.

I will introduce the LabVIEW graphical programming language via a demonstration of loop structures and simple arithmetic. I will demonstrate how similar programming can be used to automate lab equipment. I will show how LabVIEW is useful in lab automation, data collection, and data analysis.

I will briefly discuss electric and magnetic forces, and then use relativity to argue that they are related-- the differences simply depend on how you approach the problem.

The Milky Way galaxy is spinning about its axis, perhaps at varying rates in varying places. Since any observer on Earth of the Galaxy would be spinning along with it, we can ask how fast the Galaxy is spinning relative to us. Since the Small Radio Telescope (SRT) operates by interpreting light as a wave, we can calculate how fast any particular part of the galaxy is moving towards or away from us. I present a map of the rotation of the galaxy created using measurements of this Doppler shift with Guilford's SRT.