A digital camera is composed of a camera body and a lens unit removebly attached to the camera body. In a specific example, a determination is made during running of a BIST whether one or more algorithms are to be run. The compositions and methods disclosed herein provide ethylene polymers having a HLMI of from about 0. The distance between the wall of the ring sector and the bottom of the multiperforated plate defines a gap which is progressive in an axial direction, from the upstream region toward the downstream region. These devices are particularly beneficial in tubular condensers within distillation columns and may be used in combination with other associated equipment as well as in combination with the tube surface enhancements to improve the heat transfer coefficient.