Embodiments of computer-implemented methods, systems, computing devices, and computer-readable media are described herein for allowing a mobile network operator to perform services on behalf of a non-internet protocol multimedia subsystem data provider. The selective removal can utilize etchant solutions containing hydrofluoric acid and one or more carboxylic acids. The double wall structure contains a heat exchange system in heat exchange contact with the air space and the heat source that enables the transfer of heat from the air space to the exterior of the enclosure and is doubly effective in attenuating noise from the noise source to the exterior of the enclosure. A second disk is supported on the second spindle, wherein the second spindle is oriented in a second orientation and at a third acute angle relative to the lateral line. The stop piston can move to limit the movement of the pilot piston. Descriptions of the images use geometric shapes including lines, rectangles, and triangles to facilitate the comparisons and decrease comparison time and decrease stored data describing the shapes.