An emitter tip for a corona discharge device. The source waveform can be modified according to the optimization parameter resulting in a modified waveform. The method includes the step of applying voltages more than once in combination to the memory cell when the variable resistance element is changed from the low resistance state to the high resistance state. The holder may also form an insulating air gap between the beverage container and the inner surface of the holder. The at least one flexible fairing cover portion includes a face portion and an attachment portion and is operable to be removably attached to and at least partially cover the fairing frame member.