The relationship between C"peak and ice mass – The physical basis on which TVIS determines the ice sublimation rate

<p dir="ltr">This PowerPoint explains the linear relationship between the magnitude of the dielectric loss peak in the imaginary part capacitance spectrum (that results from the dielectric relaxation of ice) and the height and therefore mass of ice within the segment of the TVIS vial, which is bounded by the electrodes.</p><p dir="ltr">The linear region is only evident above a minimum height of ice mass within the electrode space, as the field lines to ground result in a smaller contribution to the measured capacitance from the ice that is contained within the lower part of the electrode system.•The consequence of this phenomenon, is that any attempt to correlate the peak height to ice mass, during the sublimation of ice in the primary drying stage of the cycle, should be restricted to the initial drying stages.</p><p dir="ltr">However, given that the point at which this linear relationship fails is well before the point when then ice mass begins to dry preferentially down the walls of the vial, means that the practical realization of TVIS in the determination of ice interface temperatures by Pikal’s models is well within the capability of the TVIS method.</p><p dir="ltr">The slide deck finishes with some diagrams to explain briefly how the average ice temperature and ice sublimation rate (determined from the TVIS parameters, F_PEAK and C_PEAK, respectively) are used to predict the ice interface and ice base temperatures, and from which the dry layer resistance and the heat transfer coefficient are determined.</p>