Safety razor entitled "Fuck Everything, We're Doing Five Blades" predicted the release of five-blade cartridges, two years before their commercial introduction. South Korean manufacturer Dorco released their own six-blade cartridge in 2012, and later released a seven-blade cartridge. Gillette has also produced powered variants of the Mach3 (M3Power, M3Power Nitro) and Fusion (Fusion Power and Fusion Power Phantom) razors. These razors accept a single AAA battery which is used to produce vibration in the razor; this action was purported to raise hair up and away from the skin prior to being cut. These claims were ruled in an American court as "unsubstantiated
Mach reflection the shock angle exceeds a certain value, the deflection achievable by a single reflected shock is insufficient to turn the flow back to a direction parallel to the wall and transition to Mach reflection is observed. Mach reflection consists of three shocks, namely the incident shock, the reflected shock and a Mach stem, as well as a slip plane. The point where the three shocks meet is known as the 'triple point' in two dimensions, or a shock-shock in three dimensions. The only type of Mach reflection possible in steady flow is direct-Mach reflection, in which the Mach stem is