Abstract: Various ducts and methods of manufacture, use, and transport are disclosed. The present disclosure at least partially addresses at least one of the above. However, the present disclosure can prove useful to other technical areas. Therefore, the claims should not be construed as necessarily limited to addressing any of the above. An embodiment comprises a method comprising: accessing a duct comprising an outer portion and an inner portion, wherein the outer portion comprises an L-shaped segment comprising a first end portion and a second end portion, wherein the first end portion comprises a first winglet extending therefrom, wherein the second end portion comprises a second winglet extending therefrom, wherein the first winglet and the second winglet contact the inner portion such that a channel is defined between the L-shaped segment and the inner portion; conducting a fluid through the inner portion.

Abstract: A method of pre-assembling two standard Z-Shaped thermoplastic sheet pile segments in a factory controlled environment where the sheets are fused or welded by a process using heat and pressure, added material or pressure without heat to create a monolithic structure that is stronger than the individual sheets used to make the final assembly. By using two existing profile extrusions that individually can be used as is or pre-assembled in the field, product quality is assured by redundant quality checks. The first, when the sheet is produced and the second, when they are assembled and fused into one.