absorbent article comprising a liquid transfer layer positioned between a liquid pervious bodyside liner and an absorbent core. The lift assist mechanism includes a lift assist spring connected to a spring shaft, and an elongated track in which an end of the lift assist spring or an end of the spring shaft are movably engaged. The device operates by producing characteristics variations in the fluid, or pulses, that are subsequently sensed by more than one detector spaced apart from the point of creation of the mark to derive a flow rate. The method enables the production of glycidol in an easy, simple and environmentally friendly way.