The invention disclosed herein is a non-volatile memory device. A first chip have center bonding pads formed on a substantially center portion thereof. The patterned polymeric layers define an elongated opening containing an array of posts therein and a plurality of channels, each channel containing a droplet generating element. Such storage containers can include one or more thermal barriers that provide enhanced resistance when subjected to liquid-poolfurnace fire tests. The representation theorem for the wave-equation is used, in combination with time-reversal invariance and reciprocity, to express the Green’s function between two points in the interior of the model as an integral over the response in those points due to sources regularly distributed on a surface surrounding the medium and the points.