Well, the long hard thesis slog continues. I’m just finished analyzing data from one of the main experiments that I had to redo as part of the thesis revision. In this experiment, I measure the magnitude of the impedance of the coupled piezoelectric/nozzle system at a whole bunch of different frequencies, and then compare that frequency response against what my model predicts. I’ve made several improvements since last time including using a digital camera to catch both voltages and the frequency from the oscilliscopes instead of trying to pick an average value and write it down. I’m also taking more data points at more frequencies. This should give me a better curve, and better data on the experimental error. It also helps that I stumbled across the fact that I’ve been using the wrong data from the wrong type of piezoceramic for the past few years. I thought I had bought Pz-28’s from Ferroperm, when in reality I had bought Pz-26s. Both materials are hard PZT type ceramics with low dielectric and mechanical losses, but the Pz-26 material is slightly stiffer, and has a few minor differences.
The response curve this time around was a lot closer to what was expected, and by varying some of the material properties around within the tolerances given by the manufacturer, I was able to get this good of a matchup:
On the happy side, it’s been wonderful to have my family back. I still don’t get to spend too much time with them (except on the 4th and 5th), but it’s so much better having them here than hundreds of miles away. Here’s a picture of James, who figured out how to crawl this week: