Joshua Gallaway – Electrochemist

Extracting data from a plot

Posted on August 23, 2014 by joshuagallaway

All the time I end up trying to extract data from a published plot, for example with the XRD traces above. My brute force method is to load the plot into some image program, then draw straight lines to all the important features. Up above I’ve drawn lines to peaks L, C, G, and F using 30 degrees as the origin. The line lengths tell you exactly where the peak maxima are, after you normalize them to a line drawn along the axis to get the scale.

Hey it’s a decent method and it works, but I was thinking how useful it would be to have a tool that reads an image file and can spit out the original data as a CSV. Turns out there are a few programs that do exactly that. I haven’t tried WebPlotDigitizer yet, but I will soon. If it’s the answer to all my hopes and dreams I’ll let you know.

A simple fuel cell

Posted on August 21, 2014 by joshuagallaway

When I was a grad student I had to run a lab for undergrads to make their own fuel cells. This was a drawing I made to explain the basic components and how they went together. The metal plates on the outside are the current collectors. At the center is the membrane-electrode assembly or the MEA. It’s a piece of solid electrolyte membrane that feels a bit like a piece of rubber. On each side is a small square of catalyst, usually platinum particles.

I have to tell you, I sort of miss painting platinum onto MEAs. However, I do not miss helping people put these together. Getting all that lined up and sandwiched together is harder than it looks.