Hey Rodney. I don't know if you read this but you could have used images from Wikipedia (or Wikimedia Commons which is the media archiv for all projects by the Wikimedia Foundation).
For this purpose http://commons.wikimedia.org/wiki/Category:Heatpipes would be an example and http://commons.wikimedia.org/wiki/File:Heatpipe_cpu_thermal_unit_cross_section.jpg would be a perfect image to show how the inside of a heatpipe looks like.