No description available.

No description available.

No description available.

Spectroscopic measurements were made on a long-lived Argon plasma to determine the electron temperature and density and to examine the validity of the thermal equilibrium relations used. The derived results when compared with Griem's equilibrium criteria indicate that a complete thermal equilibrium was not established. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

The effects of small random fluctuations on deterministic systems are studied. The deterministic systems of interest have multiple steady states. As parameters vary, two or three of the steady states coalesce. This work is concerned with the long time behavior of the system, when the system starts near an unstable steady state. The deterministic separatrix is surrounded by a tube that contains up to two stable steady states. The quantity of basic interest is the probability of first exit from the tube through a specified boundary, conditioned on initial position. In the diffusion approximation this probability satisfies a backward diffusion equation. Formal asymptotic solutions of the backward equation are constructed. The solutions are obtained by a generalized "ray method" and are given in terms of various incomplete special functions. As an example, the effects of fluctuations on a substrate inhibited reaction in an open vessel are analyzed. The theory is compared with exact solutions, for a one dimensional model; and Monte Carlo experiments, for a two dimensional model. / Science, Faculty of / Mathematics, Department of / Unknown

Internally consistent thermodynamic data for 23 phases in the CaO-Al₂O₃-SiO₂-H₂O system are determined by linear programming consistent set analysis. The consistent set analysis is based on published experimental petrology data for equilibrium reactions involving the phases in this system. Inconsistencies in the experimental data are removed by moving four data points beyond the maximum error allowed by the specific authors or by ignoring some portions of the questionable data. The phase relations among the phases between 0 to 2000°C and 0 to 50,000 bars are calculated using the consistent thermodynamic data with the computer program PT-SYSTEM written by T.H. Brown and E.H. Perkins of the Department of Geological Sciences at the University of British Columbia. The stable portions of the 236 stable equilibrium reactions are drawn on pressure-temperature (P-T) diagrams showing the phase relations of each phase. The P-T diagrams can be used to interpret the petrogenesis of metamorphic zones containing the phases. The consistent thermodynamic data in this study can be improved by undertaking petrology experiments which will substantiate and further define the data. Experiments investigating the stability of prehnite, wairakite and heulandite are recommended. Updating of the internally consistent thermodynamic properties for existing and new phases should be carried out for each additional set of experimental data by redoing the linear programming consistent set analysis on the entire experimental data set. The new thermodynamic properties for the phases could then be used to calculate the new phase relations. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

No description available.

No description available.

This thesis investigates the modelling and optimization of electro-thermal variable parameters applicable in obtaining an optimal operating point in SAFs. Graphite electrodes that are symmetrically positioned around the furnace are used to convert electrical energy to heat energy via three-phase arcs. The raw materials are fed via conveyor belts from the top of the furnace and are smelted by the arcs produced by the electrodes. The charge constitutes the resistance variable, whilst the heat emitted from the molten charge constitutes the temperature variable. The supply voltage to the furnace constitutes the last variable and it suffers from the network disturbances such as harmonics, dips, surges and others. Although there are many variables that are involved in submerged arc furnace operations, the scope of this thesis is restricted to three electro-thermal variable parameters namely, resistance, voltage and temperature. The measurement of these parameters need to be done accurately and controlled effectively in order to achieve optimum output power during the furnace operation. An amalgamated variable parameter measurement (AVPM) system is proposed for the accurate measurement of these variables by use of mathematically modeled modules. The verification of this proposed measurement system is not considered in this thesis as it is recommended for future study. Modelling is difficult using mathematical functions according to the mechanisms of the actual furnace plant system because of its complexity and many disturbances. The neural networks have been chosen because of its easy to use in modelling nonlinear functions such as the furnace plant. In this thesis, the furnace plant is modeled with the neural networks (NN) algorithm to obtain the SAF NN model. The model is then optimized using the particle swarm optimizer (PSO) algorithm. The formulated PSO based SAF NN model’s results are also validated using the real SAF plant samples. / Electrical Engineering / M. Tech. (Electrical Engineering)

No description available.