No description available.

A dissertation submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science in Engineering Johannesburg, 1994 / A quantitative description of galvanic interactions between sulphide minerals based on thermodynamic and kinetic parameters has been developed. The basis for quantitative description involves conducting a voltage balance over the galvanic couple. The contributions to the voltage balance include the galvanic couple cell emf, kinetic descriptions of the anodic and cathodic half reactions, the voltage characteristics 'of mineral-mineral contacts and solution voltage losses. The rates of the anodic and cathodic half' reactions were modelled by the Butler-Volmer equation and ti1ediffusion equation. A potentiostat was used to vary the voltages losses across mineral-mineral contacts. TIle galvanic couples were constructed. as rotating ring disc electrodes and hence electrolyte voltage losses were negligible. Three galvanic couples, copper-platinum, copper-pyrite and galena-pyrite, were electrochemically characterised under different conditions of ferric concentration, electrode rotation rate and temperature. The effect of illumination on the anodic dissolution of galena was investigated. The electrochemical model is in good agreement with experimentally measured galvanic currents. Galvanic interaction is a dynamic function and various models are developed which account for dynamic behaviour in galvanic cells. / MT2017

Thesis (MTech (Mechanical Engineering))--Peninsula Technikon, 1999. / Word processed copy. Summary in English. Includes bibliographical references (leaves 66-68). Also available online.

No description available.

No description available.

No description available.

No description available.

No description available.

Thesis (M.S.)--Rochester Institute of Technology, 1987. / Typescript. Includes bibliographical references (leaves 79-81).

Thesis (MTech (Mechanical Engineering))--Peninsula Technikon, 1999 / The simulation of Plasma Arc Cutting is presented in this study. The plasma arc cutting process employs a plasma torch with a very narrow bore to produce a transferred arc to the workpiece. A technique for modelling plasma arc cutting has been developed by applying the thermo-metallurgical model to the process and integrating a model of material removal to this model. The model is solved using the finite element method using the FE package SYSWORLD, more specifically SYSWELD. The objective is to determine the minimum energy required to cut a plate of some thickness using this virtual model. The characteristics of the cut need to exhibit the characteristics of a "high quality cut". The model presented can predict the kerf size given certain process variable settings. The numerical results obtained are assessed by conducting experiments. By maintaining Ill1rumum energy input cost savings can be made through energy savings, limiting additional finishing processes and reducing expense of shortening the electrode and nozzle lifetimes. The modelling of the PAC process using virtual design techniques provides a cost-effective solution to the manufacturing industries with respect to process specification development. This plays an important role in South Africa's transition into a competitive global market. It is envisaged that the model will provide an alternative more efficient, non-destructive means of determining the optimum process variable settings for the plasma arc cutting process.