A bird feeder provides a feed hopper constructed concentrically around a vertical central axis and having a plurality of feeding ports evenly distributed around the central axis, and a cable reel mounted to the feed hopper and adapted to store and provide a cable for supporting the bird feeder along the central axis. With a composite plate structure, the element according to the invention comprises a network of cells, more preferably of honeycomb shape, in each of which is placed a nuclear fuel pellet. The processor generates a control signal that is communicated to the gas generating modules such that the peak product gas flow period of the repetitive cycle of the modules is adjusted in response to the control signal. The framework may then be used to configure one or more selected computer systems on the network to be similar to the model computer system in one or more aspects. A photonic crystal optical waveguide and channel optical waveguide are joined together, and the structure of the channel optical waveguide is wedge shaped in the joint section.