A hydraulic accumulator is equipped with a novel shut-off valve. The screw-type electrical connector is adapted to transmit electrical power to the at least one LED. The invention is also an ink-jet cartridge having a plurality of reservoirs, some of which contain an ink having a dye and at least one of which contains a deactivating agent. The exemplary method may additionally comprise predicting fluid flow in a subsurface region based on the fault permeability.