A few grammes of 100 mm diameter polythene spheres are warm-pressed into a solid block. Describe the expected electrical characteristics of the block. In a separate experiment each sphere is first coated with a nanometer thick layer of aluminum prior to compaction. Describe how the electrical properties of the block would be modified and estimate the quantity of aluminum in the ‘composite' on the bases of volume and weight. Comment on the relevance of your finding to electro ceramics research and development 30 p.p.m.; 90 p.p.m