The present disclosure provides a computer-implemented method of performing system maintenance in a computing device. The reception light beam may arise as a result of reflection of the emission light beam at the object. In the cooling process, a vortex flow is generated by blowing out the inert gas from at least one part around the flowing passage of the metallic powder. The sleeve has a pair of opposite spaced-apart tabs in the side edges thereof that must be simultaneously pressed to unlatch the latches from the latch-catchers to permit the blister card to be slid from the storage position to a dispensing position. The cells also provide increase coverage of a vessel wall.