Permittivity dispersion measurements in a very low frequency range were made on n-pentyl (5CB) and n-octyl 8CB cyano biphenyls, providing characterization of mobile ions by the diffusion coefficient, or the mobility, and their temperature dependence in the nematic phase and/or the smectic A phase. Ionic conduction was confirmed in the nematic and the smectic A phases from the continuity of these temperature-dependent properties in the isotropic, the nematic, and the smectic A phases with reasonable changes at the transition temperatures. The Walden rule was found to be applicable to the ionic conduction in the nematic phase of 5CB without a pre-transitional phenomemon near the nematic-smectic phase transition, when appropriate mean values are taken for both the anisotropic mobility of ions and the anisotropic viscosity of the liquid crystal substance. It was also pointed out that care should be taken for the applicability of the Walden rule to liquid crystals in the case when the anisotropy of ionic conduction is argued, especially for liquid crystal materials containing mobile ions with a far less anisotropic shape than the liquid crystal molecules.
As site investigation proceeds and information obtained on geological environments increases, the characterization plan has to be iteratively reviewed and modified to reflect improved understanding. Such modification would also be needed when changes occur in technical or socio-political boundary conditions. JAEA teams involved in implementation of URL projects have used a geosynthesis data flow diagram to integrate a huge amount of practical experience in order to carry out such management functions. However, much of this experience was gained in the past, when it was possible for staff to learn by taking leading roles in novel, complex and important projects and learn by successes – and mistakes – under boundary conditions that were much more casual than they are at present. It is necessary to transfer such tacit knowledge to implementing and regulatory organizations in a practical manner before it is lost with the retirement of senior staff. An option being examined involves application of advanced technology, termed the Information Synthesis and Interpretation System (ISIS), to capture experience using Knowledge Engineering methods. This is being tested for practical applicability in an exercise involving stepwise “optimization” of a site characterization plan.
