A method and system of designing a digital halftoning screen for forming images on output sheets according to a set of image signals. The hydraulic damping means comprises a pair of hydraulic pumps or a pair of hydraulic cylinders with a dual chamber, connected in an opposite direction to each other to the hydraulic circuits. The transformer includes primary and secondary coils wound on the bobbin and an iron core mounted about the coils. A deflector may be positioned adjacent the nozzle to assist in stabilizing the flame after the expansion and slowing process has been completed. A microcapsule obtained in such a way contains most of the solid pesticidal compound within the microcapsule.