Thermodynamics of Bi2O3-SiO2 system

Thermodynamic properties of the liquid Bi2O3-SiO2 solutions were determined from the results of the electrochemical measurements by use of the solid oxide galvanic cells with YSZ (Yttria-Stabilized-Zirconia) electrolyte. Activities of Bi2O3 in the solutions were determined for 0.2, 0.3, 0.4, and 0.5 SiO2 mole fractions in the temperature range 1073-1293 K from measured electromotive force (e.m.f) of the solid electrolyte galvanic cell: Bi, Bi2O3-SiO2 | YSZ | air (pO2 = 0.213 bar) Additionally, heat capacity data obtained for two solid phases 6Bi2O3?SiO2 and 2Bi2O3?3SiO2 were included into optimization of thermodynamic properties of the system. Optimization procedure was supported by differential thermal analysis (DTA) data obtained in this work as well as those accepted from the literature. Using the data obtained in this work, and the information about phase equilibria found in the literature, binary system Bi2O3-SiO2 was assessed with the ThermoCalc software.

Measuring Behavior of Impactor Penetrating through Polymer Sheet Based on Electromagnetic Induction

In the paper, the behavior of an impactor penetrating through a polymer sheet was measured using electromagnetic induction phenomena. First, electromotive forces generated in a coil were measured to decide the relation between the impactor velocity and the electromotive force when the impactor with an embedded neodymium magnet passed through a coil at several constant velocities. The intensity of the electromotive force was found to be proportional to the impactor velocity at each impactor position. The relation was used as the calibration data to calculate the velocity and position of the impactor. Next, penetration tests of polyvinyl chloride sheets were conducted with the coil set at the front of the sheet. The electromotive force generated in the coil was measured when the impactor penetrated through the sheet. The impactor velocity and position were calculated from the electromotive force with the calibration data. The validity of the measuring method was confirmed because the calculated results from the measured electromotive force agreed with the observed results by using a high speed video camera.

Calibration of Ion-Selective Electrodes for Use in Biological Fluids

We measured electromotive force at 37 °C with pH, sodium glass, valinomycin, and the Simon calcium electrodes in synthetic electrolyte mixtures simulating serum, in cells both with and without liquid junction. Evidently these electrodes respond in a near-Nernstian manner to changes in concentration of the ion sensed. We suggest that such mixtures may serve as calibrating standards for ion-selective electrodes in clinical analysis. The effect of ionic strength on electrode response can be accounted for almost wholly by alterations in the activity coefficients. The lanthanum fluoride electrode shows promise as a reliable reference in cells without liquid junction.

Electromotive force of transfer systems containing membranes

Reversible Ag-AgCl electrodes have been inserted in the phases of a unit transfer system, phase agr, membrane, phase β, and the electromotive force of the chemical source of electromotive force so produced has been determined in the presence of varying material flows through the membrane. The measured electromotive force was found to be a linear function of the ion-pair chemical potential difference between the phases when the concentration of the salt in the more concentrated phase was less than 0.5 M. This relation implies that an electric transport number, a mutual property of the ion and the membrane, is constant over a wide concentration range when a single salt is present in the system. When the system is in a stationary state, the emf is a linear function of the flow rate of water over the concentration range studied. Two membranes whose electric transport numbers are different, a millipore filter and a cellophane membrane, were used to construct a closed circuit containing two aqueous homogeneous phases of different concentrations. Evidence is presented which demonstrates that a spontaneous electric current flows in such a closed circuit. membrane phenomena; electric transport number; nonequilibrium systems; electrochemical source of emf in closed circuits Submitted on June 6, 1963