02 October 1987
Vol 238, Issue 4823

About The Cover

Electric power dissipation levels in a vertical slit with finite electrodes. Joule heating is greatest near the electrode tips (black semicircles) and decreases by roughly half with each color change, from blue to green to red. Temperature gradients produced by Joule heating drive unstable nature convection. The picture was generated numerically using Laplace's equation for the potential. See page 58. [William A. Gobie, Department of Chemical Engineering, Washington State University, Pullman, WA 99164]