During the recent years, with its increasing steel production, Turkey has succeeded to become one of the ten biggest steel producer countries in the world. In Turkey, there are 3 integrated plants and 27 Electric Arc Furnace (EAF) plants in operation for iron-steel production. 71,3 % of the steel products was produced by EAF plants and also it is planned for new plants to produce with arc furnaces. In this study, power quality problems caused by 60MVA arc furnace at Sivas Iron and Steel Incorporated Company (SIDEMIR), have been examined by HIOKI 3197 and Chauvin Arnoux(CA) 8332B power quality analysers according to IEC 61000-4-30 standards. In addition, with equivalent circuit model designed by utilizing Electromagnetic Transient Program(EMTP) software, possible harmonic effects on the electricity grid have been evalauted and by determining power quality problems caused by EAF-60 furnace, solution offers were presented in order to improve power quality.

The effects of electromagnetic waves in drying processes of solid materials are investigated theoretically and experimentally. Modified model of mass transfer being constituted by the effect of electromagnetic waves which have different frequency has been obtained. Modeling of the drying process with a two-port electric circuit for the determination of diffusion coefficients is designed. The frequency limits of electromagnetic wave which will be able to hasten the drying process are determined. The effects of the electromagnetic wave in the potato slice drying process by the influence of different frequencies and temperatures are experimentally examined. The results obtained are compared with theoretical calculations. Moisture concentration curves in drying process have been commented by drawing. Theoretical and experimental results which have been obtained are identified as a well adaptation.

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As a result of the sedimentation of dispersed particles in channels and ducts, distribution function with respect to the particle sizes changes. Particle sedimentation is affected by the gravitational forces and the diffusional migrations to channel walls. In this article, particle sedimentation in vertical and horizontal channels is investigated depending on Pe and Re d numbers. Futhermore, new expressions for the calculation of sedimentation velocity depending on the diffusional migrations in turbulent flow were developed. Finally, a distribution function resulting from the particle sedimentaton was suggested. The suggested mathematical expressions were compared with the experimental results given in the literature and a very good aggrement was found.

Electric Arc Furnaces (EAF) are nonlinear loads causing power quality problems on the systems they are connected to. The main reason of EAFs causing power quality problems is the nonlinear characteristics of the electric arc. In this study, dynamic working characteristics of electric arc furnace load at Sivas Iron and Steel Incorporated Company (SIDEMIR) operating with 60 MVA EAF have been experimentally examined by HIOKI 3197 PQ analyser. Utilizing the measured dynamic load curves, mathematical equation and proper parameters have been determined for modelling electrical arc with the help of curve fitting methods on Matlab program. Also by modeling a phase equivalent of the system and harmonic filters existing on the system, a time domain model has been formed and with this model, harmonic effects of the EAF have been examined with Matlab/Simulink. Simulation results show that the presented model can be used for examining PQ and voltage harmonics problems caused by EAF loads.