At least one of the spacing between the windings along the longitudinal axis or {HEAD ~ the angle} of slope between the windings and the longitudinal axis varies in {TAIL ~ certain sections} to change the winding density as a function of local mechanical load requirements on the pipeline 
At least one of the spacing between the windings along the longitudinal axis or { HEAD ~ the angle } of slope between the windings and the longitudinal axis varies in { TAIL ~ certain sections } to change the winding density as a function of local mechanical load requirements on the pipeline
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