Abstract: A composite ceramic including a first phase of ceramic material and a second phase of ceramic material, the first and second phases forming three dimensional interconnected networks of each phase and having a nano-scaled grain size. The composite ceramic is produced in a method which utilizes rapid solidification at cooling rates of at least ˜104° K./sec to produce a metastable material formed by a solid solution of a two immiscible ceramic material phases, and which also utilizes relatively high pressure/low temperature consolidation to complete densification of the metastable material, while simultaneously generating a composite structure with nano-scale grain dimensions through a controlled phase transformation.

Abstract: Energy dispersive x-ray diffraction spectra are obtained from numerous volume elements within an object. A feature set such as a set of cepstrum coefficients is extracted from each spectrum and classified by a trained classifier such as a neural network to provide an indication of whether or not contraband such as explosives is present in the volume element. Indications for adjacent volume elements are evaluated in conjunction with one another, as by an erosion process, to suppress isolated indications and thereby suppress false alarms.