Investigation of the effects of thermal and chemical impurities on the phase transition curves of home-made mercury triple point cells

This thesis is concerned with the construction and characterization of mercury triple point cells for the first time in our country. The triple point of mercury with associated temperature value of -38.8344 °C has a unique importance in international temperature scale since it is the only defined fixed point between the temperature range -190 °C and 0.010 °C. Within the scope of the thesis study, the effect of purification of mercury on the triple point temperature besides the effect of filling technique was investigated. Three different methods of qualitative assessment - overall maximum estimate, 1/F realization curve and direct comparison - for the impurity content in mercury cells were utilized. To achieve this, three cells, having mercury samples of different purity values inside were fabricated. A brand new design for these cells was developed to maintain high accuracy measurements with the mercury in smaller amounts than the conventional cells contain. Also the dependence of the shape of melting plateaus on the preceding freezing conditions was analyzed. Later the shape of melting plateaus which was observed to be affected by non-uniform thermal environment enclosing the cell, the chosen range of 1/F versus temperature difference curve and chemical impurities were examined. In order to estimate the extent of the effects, a statistical method called ?analysis of variance? (ANOVA) was used. Finally the parameters constituting the uncertainty budgets regarding the measurements of the thesis study were decided and assessed. At the end of the thesis study, a new national standard mercury triple point was accomplished with lower uncertainty