Below is a list of the research projects that have been of interest over the years. The list is mostly chronological with the newest first and consists largely of summaries. If you are interested in hearing more I will attempt to put citations or links for articles and you can always email me!
Interference-Particle Tracking Velocimetry
A persistent problem in microfluidics is a lack of three dimensional fluid velocity measurement techniques. The reasons for this lack are due largely to the small size of the flows involved. There simply isn’t room for multiple cameras or perspectives that are the mainstays of many macroscale 3D velocimetry techniques. As a result it is necessary to get clever and to make use of what information you have.
The result is a measurement technique I invented called Interference Particle Tracking Velocimetry. This technique is fairly unique because it doesn’t rely on distortions of the particle image to determine the depth of the particle. Instead, it transforms the particle’s wavefront into a Bessel beam and then uses several key features of the Bessel Beam to determine the three dimensional location of the particle. This has several advantages:
- Zero calibration. If you know the optical components of your imaging system you can plug it in and start taking measurements.
- Large measurement depth. I can easily achieve a measurement depth of over 200 um with a 20x lens. This depth is easily customizable by changing key optical components of my design.
- Technique does not rely on a single particle feature. As a result my technique is insensitive to changes in particle size or intensity.
It turns out that sharks have many more tricks up their sleeves (fins?) for hunting fish then you would expect at first. At a really short range they can use their eyes and a set of electric field sensing pores along their flanks. At longer range they can use their sense of smell and what appears to be a super-sensitive ability to sense temperature gradients. How they sense these gradients was the subject of my research. We believed that the electrical sensing pores in the skin of sharks is filled with a gel that produces a very large voltage in response to temperature gradients. It was our hope that we could eventually harness the mechanism behind this large voltage in response to a temperature gradient (thermoelectricity) as an energy source.
The results of my research indicated that while the gel does indeed produce a very large voltage in response to temperature gradients this is a behavior typical of strongly ionic solutions. While that is somewhat disappointing I learned a tremendous amount about electro chemistry and the wonderful complexity of ionic solutions, something I hope to study further in the future.