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Electrical Fault Analysis
Published in Amitava Sil, Saikat Maity, Industrial Power Systems, 2022
Earthing system is designed to achieve low earth resistance and also to achieve safe “Step Potential” and “Touch Potential”. Step Potential is the potential difference between two points on the earth’s surface, separated by distance of one pace that will be assumed to be 1 m in the direction of maximum potential gradient. Touch Potential is the potential difference between a grounded metallic structure and a point on the earth’s surface separated by a distance equal to the normal maximum horizontal reach, approximately 1 m.
Optimal site selection for wind energy: a case study
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
In this study, the site selection problem for wind energy is discussed. The main purpose of the study is to ensure the optimum design for providing the energy need. In the study, all provinces in Turkey are assessed. The aim is to find the most optimal site selection. The flow chart of the developed system is illustrated in Figure 1. The study takes place in four steps. As a first step, potential wind energy data are compiled. As a second step, the application of the Pareto diagram provides the determination of high potential provinces. This step determines the provinces that account for approximately 80% of Turkey’s total wind energy potential. After that, with the forecasting methods, electricity consumption estimates of high potential provinces in the future are performed. In this step, the ARIMA method and time series analysis method are used. As the last step, an integrated mathematical programming model with estimation outputs is developed. As a result of the algorithm, it is determined in which province the installation decision will be made, how many installations will be in total, and what the appropriate capacities of the provinces are.
The bifunctional role played by thiocyanate anions on the active dissolution and the passive film of titanium in hydrochloric acid
Published in Corrosion Engineering, Science and Technology, 2022
Ibrahim H. Elshamy, Sayed S. Abd El Rehim, Magdy A. M. Ibrahim, Nobl F. El Boraei
Figure 11 shows a series of chronoamperometry current–time transients for a Ti electrode in a 12.0 wt-% HCl solution at varying anodic step potentials (Ea’s) (0.05–0.5 V) at 25°C. The transient current gradually decreases over time to achieve a steady-state value. The instantaneous and steady-state currents increase as the anodic step potential becomes more positive. Each transient begins with a charging current which deteriorates throughout the nucleation and early surface oxide film growth, followed by a steady-state value (attributed to the poor conducting influence of the oxide layer produced)-plotting the current density, i vs. t−1/2. The slopes of the lines for the descending portion of current transients (Figure 11 inset) depend on the step potential values. Under these conditions, a linear relationship confirms the fact that the formation of the Ti oxide film is a diffusion-controlled operation, and it is subject to Equation (9) [48]. where n is the exchange electron number, C is the concentration, and D is the diffusion coefficient of the diffusion species. As a result, Ti anodic oxide film formation might be started through the dissolution of metal followed by a nucleation and growth mechanism under diffusion control.
Corrosion inhibition effect of calcium gluconate on mild steel in artificial seawater
Published in Cogent Engineering, 2020
Roland Tolulope Loto, Muyiwa Fajobi, Oluleke Oluwole, Cleophas Akintoye Loto
MS of cylindrical dimension (0.7 cm diameter) was manually cut into five test coupons. Each coupon was mounted in acrylic paste which hardened after 5 min, grinded with emery abrasive papers (80, 120, 240, 320, 400, 600, 800 and 1,000 grits), polished with diamond polishing paste and subsequently washed with distilled H2O and acetone for potentiodynamic polarization technique and open circuit potential (OCP) measurement. Seven grams of recrystallized NaCl was added to 200 ml of distilled H2O to formulate to simulate artificial seawater. CGN obtained from Sigma Aldrich, USA was prepared in volumetric concentrations of 0.75%, 1.25%, 1.75% and 2.25%% per 2,000 ml of artificial seawater. The compound is non-toxic with molecular weight of 430.373 g/mol with molecular formular of C12H22CaO14. Its molecular structure is shown in Figure 1. Potentiodynamic polarization test was done with Digi-Ivy 2300 potentiostat at 25°C ambient temperature. Resin mounted MS electrodes (exposed surface area of 0.38 cm2), Pt counter electrode and silver chloride reference electrode (Ag/AgCl) were immersed in artificial seawater solution, and connected to the Potentiostat–computer interface. Potentiodynamic measurement was performed between potentials of −1.5 V to 0.5 V at a scan rate of 0.0015 V/s. OCP measurement was performed for 9,000 s at 0.2 V step potential. Omax trinocular metallurgical microscope was used to study and capture images of MS surface before corrosion and after corrosion with and without CGN inhibitor.