The Experts below are selected from a list of 171 Experts worldwide ranked by ideXlab platform

Sherif Omar Faried - One of the best experts on this subject based on the ideXlab platform.

  • Effect of sequential reclosure of Multi-Phase System faults on turbine-generator shaft torsional torques
    IEEE Transactions on Power Systems, 1991
    Co-Authors: A.m. El-serafi, Sherif Omar Faried
    Abstract:

    The authors present a method of reducing the high torsional torques induced in turbine-generator shafts during high-speed reclosure of multiphase System faults. The method is based on the sequential reclosing of the faulted circuit. In this context, investigations have been conducted on two turbine-generator units of different designs for various multiphase System faults. The results of both the three-phase-to-ground and double-line-to-ground faults are reported, and the effectiveness of the method is illustrated through parametric studies and simulation results. The effects of the reclosing time and the fault incidence instant on the effectiveness of the method have also been investigated

Evgueni Jak - One of the best experts on this subject based on the ideXlab platform.

  • The Effect of MgO on Gas–Slag–Matte–Tridymite Equilibria in Fayalite-Based Copper Smelting Slags at 1473 K (1200 °C) and 1573 K (1300 °C), and P(SO_2) = 0.25 atm
    Journal of Phase Equilibria and Diffusion, 2020
    Co-Authors: Hamed Abdeyazdan, Ata Fallah-mehrjardi, Peter C. Hayes, Taufiq Hidayat, Maksym Shevchenko, Evgueni Jak
    Abstract:

    Understanding the significance of magnesia as a common component in copper processing slags is essential for optimisation of the industrial copper production. Fundamental experimental studies have been undertaken to determine the effect of MgO on the equilibria between the gas phase (CO-CO_2-SO_2-Ar) and slag-matte-tridymite phases in the Cu-Fe-O-S-Si-Mg System at 1473 K (1200 °C) and 1573 K (1300 °C), and P (SO_2) = 0.25 atm. The experimental methodology used was based on equilibration, quenching and microanalysis. New experimental data have been obtained for the four-phase gas–slag–matte–tridymite equilibria System for a range of MgO concentrations up to 3.1 wt pct in the slag phase as a function of matte grade, including the concentrations of dissolved sulphur and copper in slag, and Fe/SiO_2 ratios in slag. The results are also used to analyse the effect of temperature on phase equilibria in the range investigated. The results obtained showed that dissolution of sulphur, copper and “FeO” in slag decreases with increase of MgO in slag while it has no detectable effect on concentration of sulphur in matte. Also, dissolved copper and sulphur in slag increases when temperature increases while the Fe/SiO_2 ratio in slag is greater at 1473 K (1200 °C) than 1573 K (1300 °C). The new data provided in the present study are of direct relevance to the pyrometallurgical processing of copper and will be used as an input for optimization of the FactSage thermodynamic database for the copper-containing multi-component Multi-Phase System.

  • Experimental Study of Gas-Slag-Matte-Tridymite Equilibria in the Cu-Fe-O-S-Si-Al System at 1573 K (1300 °C) and P(SO_2) = 0.25 atm
    Journal of Phase Equilibria and Diffusion, 2020
    Co-Authors: Hamed Abdeyazdan, Ata Fallah-mehrjardi, Peter C. Hayes, Taufiq Hidayat, Maksym Shevchenko, Evgueni Jak
    Abstract:

    Fundamental experimental investigations have been conducted to study the effect of Al_2O_3 on the equilibria between the gas phase (CO-CO_2-SO_2-Ar) and slag-matte-tridymite phases in the Cu-Fe-O-S-Si-Al System at 1573 K (1300 °C) and P (SO_2) = 0.25 atm. The experimental technique used is based on equilibration, rapid quenching and electron probe x-ray microanalysis. New experimental data have been obtained for the four-phase gas-slag-matte-tridymite equilibria System for a range of alumina concentrations up to 20.4 mass% in the slag phase as a function of matte grade, including the concentrations of dissolved sulphur and copper in slag, and Fe/SiO_2 ratios in slag. The results obtained for 1573 K (1300 °C) are also used to analyse the effect of temperature on phase equilibria in the range of conditions investigated to that of reported for 1473 K (1200 °C) in the literature. The results obtained show that the concentrations of sulphur, copper and “FeO” in slag decrease with increase of Al_2O_3 concentration in slag while it has no detectable effect on concentration of sulphur in matte for a given matte grade. The new data provided in the present study are of direct relevance to the pyrometallurgical processing of copper and will be used as an input for optimisation of the FactSage thermodynamic database for the copper-containing, multi-component Multi-Phase System.

  • The Effect of CaO on Gas/Slag/Matte/Tridymite Equilibria in Fayalite-Based Copper Smelting Slags at 1473 K (1200 °C) and P(SO_2) = 0.25 Atm
    Metallurgical and Materials Transactions B, 2018
    Co-Authors: Ata Fallah-mehrjardi, Peter C. Hayes, Evgueni Jak
    Abstract:

    Fundamental experimental studies have been undertaken to determine the effect of CaO on the equilibria between the gas phase (CO/CO_2/SO_2/Ar) and slag/matte/tridymite phases in the Cu-Fe-O-S-Si-Ca System at 1473 K (1200 °C) and P (SO_2) = 0.25 atm. The experimental methodology developed in the Pyrometallurgy Innovation Centre was used. New experimental data have been obtained for the four-phase equilibria System for fixed concentrations of CaO (up to 4 wt pct) in the slag phase as a function of copper concentration in matte, including the concentrations of dissolved sulfur and copper in slag, and Fe/SiO_2 ratios in slag at tridymite saturation. The new data provided in the present study are of direct relevance to the pyrometallurgical processing of copper and will be used as an input to optimize the thermodynamic database for the copper-containing multi-component Multi-Phase System.

Song Bae Kim - One of the best experts on this subject based on the ideXlab platform.

  • Clarification of nonlinear retardation factors for colloid-enhanced transport in porous media
    Hydrogeology Journal, 2007
    Co-Authors: Meejeong Kim, Song Bae Kim
    Abstract:

    There have been a couple of contaminant retardation factors reported for the three-phase (aqueous, solid, and colloid) groundwater System. However, the retardation factor has often been presented by itself and not incorporated into the relevant transport equation, particularly when derived from the mass fraction approach. This may cause a misunderstanding of the retardation factor especially for the Systems where Multi-Phases exist due to the presence of colloids and/or nonlinear sorption processes are involved. It is, therefore, necessary to clarify the form of the nonlinear retardation factor along with the relevant transport equation in the Multi-Phase System. Alternative forms of the retardation factor and relevant transport equation for specific conditions are presented in various combinations of the nonlinearity of involved sorption mechanisms. The retardation factors for specific conditions are compared with the ones available in the literature. The results indicate that more caution should be given in applying the retardation factor in order to explore contaminant transport in the Multi-Phase System where any nonlinear sorption is involved. Finally, presentation of the retardation factor along with the relevant transport equation in this study would help prevent possible misuse of the retardation factor in investigating contaminant transport in the Multi-Phase System.

  • Equilibrium approaches to organic contaminant transport modeling in a Multi-Phase groundwater System.
    Environmental technology, 2004
    Co-Authors: Song Bae Kim
    Abstract:

    Mathematical models were developed in this study based on equilibrium sorption approaches to simulate transport and retardation of organic contaminants such as polycyclic aromatic hydrocarbons in a Multi-Phase groundwater System. In a model development, the Langmuir or Freundlich sorption isotherms were incorporated into a retardation factor to account for nonlinear sorption of contaminants and colloids on solid matrix. Numerical solutions of model equations were obtained using a fully implicit finite difference method. Simulation results showed that the contaminant retardation factor varied temporally and spatially in a Multi-Phase System (dissolved phase, solid phase, and two mobile colloidal phases). Simulation also indicated that colloidal concentration and mobility would be key factors in controlling the contaminant transport in a Multi-Phase System. Sensitivity analysis demonstrated that the models were sensitive to changes of nonlinear isotherm coefficients and equilibrium distribution coefficients.

  • Application of generalized contaminant retardation factor to a Multi-Phase System
    Hydrological Processes, 2003
    Co-Authors: Song Bae Kim, Dong Ju Kim
    Abstract:

    In this study, a generalized contaminant retardation factor applicable to a multiphase System where various types of colloids exist simultaneously with contaminants is derived and incorporated into an equilibrium model which is successfully applied to experimental data for which phenanthrene was used as hydrophobic organic contaminants and dissolved organic matter (DOM) or bacteria as mobile carriers. Based on the parameter values for the experimental data regarding the association of phenanthrene with solid matrix, DOM and various bacterial isolates, numerical experiments are performed to examine the transport behaviour of hydrophobic organic contaminants in various types of the multiphase System. Numerical experiments demonstrate that the extent of contaminant transport enhancement depends on the adsorption affinity of the colloid, its concentration and its mobility, and that the importance of a third phase to contaminant transport needs to be evaluated carefully with respect to the relevance of experimental conditions applied to realistic environmental conditions. Copyright  2003 John Wiley & Sons, Ltd.

A.m. El-serafi - One of the best experts on this subject based on the ideXlab platform.

  • Effect of sequential reclosure of Multi-Phase System faults on turbine-generator shaft torsional torques
    IEEE Transactions on Power Systems, 1991
    Co-Authors: A.m. El-serafi, Sherif Omar Faried
    Abstract:

    The authors present a method of reducing the high torsional torques induced in turbine-generator shafts during high-speed reclosure of multiphase System faults. The method is based on the sequential reclosing of the faulted circuit. In this context, investigations have been conducted on two turbine-generator units of different designs for various multiphase System faults. The results of both the three-phase-to-ground and double-line-to-ground faults are reported, and the effectiveness of the method is illustrated through parametric studies and simulation results. The effects of the reclosing time and the fault incidence instant on the effectiveness of the method have also been investigated

Ata Fallah-mehrjardi - One of the best experts on this subject based on the ideXlab platform.

  • The Effect of MgO on Gas–Slag–Matte–Tridymite Equilibria in Fayalite-Based Copper Smelting Slags at 1473 K (1200 °C) and 1573 K (1300 °C), and P(SO_2) = 0.25 atm
    Journal of Phase Equilibria and Diffusion, 2020
    Co-Authors: Hamed Abdeyazdan, Ata Fallah-mehrjardi, Peter C. Hayes, Taufiq Hidayat, Maksym Shevchenko, Evgueni Jak
    Abstract:

    Understanding the significance of magnesia as a common component in copper processing slags is essential for optimisation of the industrial copper production. Fundamental experimental studies have been undertaken to determine the effect of MgO on the equilibria between the gas phase (CO-CO_2-SO_2-Ar) and slag-matte-tridymite phases in the Cu-Fe-O-S-Si-Mg System at 1473 K (1200 °C) and 1573 K (1300 °C), and P (SO_2) = 0.25 atm. The experimental methodology used was based on equilibration, quenching and microanalysis. New experimental data have been obtained for the four-phase gas–slag–matte–tridymite equilibria System for a range of MgO concentrations up to 3.1 wt pct in the slag phase as a function of matte grade, including the concentrations of dissolved sulphur and copper in slag, and Fe/SiO_2 ratios in slag. The results are also used to analyse the effect of temperature on phase equilibria in the range investigated. The results obtained showed that dissolution of sulphur, copper and “FeO” in slag decreases with increase of MgO in slag while it has no detectable effect on concentration of sulphur in matte. Also, dissolved copper and sulphur in slag increases when temperature increases while the Fe/SiO_2 ratio in slag is greater at 1473 K (1200 °C) than 1573 K (1300 °C). The new data provided in the present study are of direct relevance to the pyrometallurgical processing of copper and will be used as an input for optimization of the FactSage thermodynamic database for the copper-containing multi-component Multi-Phase System.

  • Experimental Study of Gas-Slag-Matte-Tridymite Equilibria in the Cu-Fe-O-S-Si-Al System at 1573 K (1300 °C) and P(SO_2) = 0.25 atm
    Journal of Phase Equilibria and Diffusion, 2020
    Co-Authors: Hamed Abdeyazdan, Ata Fallah-mehrjardi, Peter C. Hayes, Taufiq Hidayat, Maksym Shevchenko, Evgueni Jak
    Abstract:

    Fundamental experimental investigations have been conducted to study the effect of Al_2O_3 on the equilibria between the gas phase (CO-CO_2-SO_2-Ar) and slag-matte-tridymite phases in the Cu-Fe-O-S-Si-Al System at 1573 K (1300 °C) and P (SO_2) = 0.25 atm. The experimental technique used is based on equilibration, rapid quenching and electron probe x-ray microanalysis. New experimental data have been obtained for the four-phase gas-slag-matte-tridymite equilibria System for a range of alumina concentrations up to 20.4 mass% in the slag phase as a function of matte grade, including the concentrations of dissolved sulphur and copper in slag, and Fe/SiO_2 ratios in slag. The results obtained for 1573 K (1300 °C) are also used to analyse the effect of temperature on phase equilibria in the range of conditions investigated to that of reported for 1473 K (1200 °C) in the literature. The results obtained show that the concentrations of sulphur, copper and “FeO” in slag decrease with increase of Al_2O_3 concentration in slag while it has no detectable effect on concentration of sulphur in matte for a given matte grade. The new data provided in the present study are of direct relevance to the pyrometallurgical processing of copper and will be used as an input for optimisation of the FactSage thermodynamic database for the copper-containing, multi-component Multi-Phase System.

  • The Effect of CaO on Gas/Slag/Matte/Tridymite Equilibria in Fayalite-Based Copper Smelting Slags at 1473 K (1200 °C) and P(SO_2) = 0.25 Atm
    Metallurgical and Materials Transactions B, 2018
    Co-Authors: Ata Fallah-mehrjardi, Peter C. Hayes, Evgueni Jak
    Abstract:

    Fundamental experimental studies have been undertaken to determine the effect of CaO on the equilibria between the gas phase (CO/CO_2/SO_2/Ar) and slag/matte/tridymite phases in the Cu-Fe-O-S-Si-Ca System at 1473 K (1200 °C) and P (SO_2) = 0.25 atm. The experimental methodology developed in the Pyrometallurgy Innovation Centre was used. New experimental data have been obtained for the four-phase equilibria System for fixed concentrations of CaO (up to 4 wt pct) in the slag phase as a function of copper concentration in matte, including the concentrations of dissolved sulfur and copper in slag, and Fe/SiO_2 ratios in slag at tridymite saturation. The new data provided in the present study are of direct relevance to the pyrometallurgical processing of copper and will be used as an input to optimize the thermodynamic database for the copper-containing multi-component Multi-Phase System.