Lee Walsh's quarter with Prof. Hamm at UCACH

Lee spent the months of October-December with Prof. Eugenio Hamm, developing his experiment on interacting d-cones in a thin sheet. Lee began work on this experiment in June 2007 as an undergraduate intern. This experiment was the subject of Wei Ng's bachelor's thesis in physics in 2008. Lee's second visit continues the collaboration. For further background on the experiment, search under Hamm or Eugenio Hamm. Lee reports as follows:

I set up the fingers to be automatic using small precise motors
plugged into LabView. They are now timed with the camera, the laser
sheet (which illuminates the cross-section of the cylinder for an
image from below) and the finger depth to take automatic data for a
series of finger depths. The height of the laser sheet is adjustable
as well.

I also created a series of Matlab programs that adjust and analyze
the images from the Labview program. It can now obtain a set of
parameters which describe the curve (of the surface at the level of
the laser sheet) and therefore of the shape, size and separation of
the d-cones. The values include
1. Angular position of the d-cone (defined as of now by the point of
greatest curvature, which may be a problem when the two inner cones
are near collapse that they form one common point of greatest
curvature.) 
2. Amplitude of the d-cone (defined as distance between the two
dcones of pair, which is directly related to the effective "z" or
depth of the finger. The effective z is not the same as the imposed
depth of the finger because what Wei calls the ridge-dent becomes
skewed under pressure from the other pair of dcones, giving an
effective z greater than the imposed finger depth.) The effective z
can be calculated from the ridge-dent length, and vice versa. The
results of the calculation at this point are currently slightly
dependent on which direction the calculation is done (measure
distance, calculate z or measure z, calculate distance). Both can be
measured from the same image, but they remain to be reconciled.