A15 road (England) over the old route of the A15 (B1206) and over the South Trans-Pennine railway. At junction 5, the A15 reforms at the dual-grade "Barnetby Top Interchange", which is crossed by the Viking Way and has an exit to Elsham. It continues north as a dual carriageway which carries about as little traffic as the M180. The M180 drops to two lanes under this roundabout and continues to Grimsby and Immingham as the A180. The A15 towards the Humber Bridge, goes directly across the runways of the former RAF Bomber Command airfield at RAF Elsham Wolds (where over 1000 of its
A15 phases tungsten was examined. Discussion of whether the β–tungsten structure is an allotrope of tungsten or the structure of a tungsten suboxide was long-standing, and even in 1998 articles about the discussion were published. It seems most likely the material is a true allotrope of tungsten. The first inter-metallic compound discovered with typical AB composition was chromium silicide CrSi, discovered in 1933. Several other compounds with A15 structure were discovered in following years. No large interest existed in research on those compounds. This changed with the discovery that vanadium silicide VSi showed superconductivity at around 17 K in 1953. In following