A metallurgical furnace, which includes a furnace shell, an exhaust system, and a gas cleaning system, further includes a plurality of improved pipes and fume ducts throughout to increase operational life and productivity. One embodiment of the invention comprises axially rotating a waveguide which has a core, shining a light through a light transmission pathway in the core of the waveguide, and shaping an outer surface of the waveguide in a predetermined pattern with respect to the light transmission pathway. Embedded translations that are in the hidden layer of the search results become overt when a user actively requests to see them, per given word or phrase, using any activation method. Two prosthetic devices are inserted into the intervertebral disk of the spine, and fixed at a predetermined angle. An interference is formed between a cold working tool and the metal layers results in a radial force that is applied only to the metal layers. The tube is fabricated of aluminum, and the step tread is fabricated of plastic or rubber.