An empirical approach for the evaluation of shielding materials for macrochemical manipulations of spontaneously fissioning heavy elements (curium and californium) has revealed interesting comparisons. High-density metal halide solutions were compared with lead glass and with rare earth glass for use as shielding windows. Laminated shields of lead-paraffin and uranium-paraffin were compared with water and with paraffin for shielding walls.

The problem of the reduction of an arbitrary truth function to the minimal union of basic cells is discussed. The solution to this problem has applications to pattern recognition and logical circuit design. An algorithm is presented that solves the problem and generates the class of minimal unions. It partitions an arbitrary truth function into a well-defined set of subfunctions (components) in such a way that the partition is invariant under all transformations that preserve the topology of the original truth function.