Methods for cooling computer systems are provided, in which the computer system has a processor and a fan. In one embodiment, the dimension of the portion of the probe arm that is in the field-of-view of the IVUS imaging element is minimized. Multiple blades rotate through a horizontal axis into the wind to lessen air resistance on one side while turning vertically on the other side to gain energy from the wind. The base is positioned on the bearing surface and includes an installing surface substantially perpendicular to the bearing surface. 001% to about 5% by weight of at least one base-catalyzed branched reaction product comprising the following reactants:. The bottom of the buffer is vertically displaced in response to the height of the articles in the buffer in a continuous or step-wise function to maintain the fill level of the articles in the buffer at substantially a constant drop distance from the source.