|, 2. modul, 2005, id:227|
|Vejleder:||Tage Emil Christensen|
|Findes på RUb:|
The main issue of this report is to evaluate, if there is an empirical basis for a correlation between the fragility and Poissions ratio for supercooled liquids. The evaluation takes its startingpoint in (Novikov & Sokolov, 2004) and (Novikov et al., 2005) in which claims of such a correlation have been made. Empirical data acquired from litterature as well as data on four selected liquids, which have been experimentally acquired will be included in the evaluation process. The latter data has been determined by measuring the change in capacity as a function of frequency for piezoelectric ceramic-transducers, which produce either a shear or a bulk deformation on the selected liquids. Such measurments have been conducted at different temperatures near the glass temperature of the selected liquids. Based on the obtained empirical data, it will be evaluated whether there is a clear tendency for a greater fragility to correspond with a greater Poissons ratio. However the uncertainties and deviations concerning the empirical data are of such a magnitude, that there is no basis for describing the tendency with an equation. Neither can the tendency be considered generally applicable, since among the selected empirical data are found liqiuds, which systematically deviate from the tendency, among these are polymers and metal alloys.