A transformer-coupled plasma source using toroidal cores forms a plasma with a high-density of ions along the center axis of the torus. The variable retarder is a nematic liquid crystal layer that is energized by an electric field and, for example, the voltage or frequency of the electric field dictates an amount of retardation effected by the variable retarder. The first computer includes a virtual machine and kernel software layer for transferring messages, including a remote virtual machine. The biodegradable substrate can be used in absorbent personal care product, biomedical devices and food packaging.