No abstract

Multi-layer laminar unsteady flows of immiscible fractional second grade fluids in a rectangular channel made by two parallel plates are studied. The fluid motion is produced by the motion of parallel walls in their plane and by the timedependent pressure gradient in the presence of the linear fluid-fluid interface conditions. The mathematical model is based on the generalized constitutive equations for the shear stress described by the time-fractional Caputo derivative. Integral transforms (finite Fourier sine transform and Laplace transform) have been used to obtain analytical and semi-analytical solutions for velocity, shear stress and the temperature fields. In the case of semi-analytical solutions, the Talbot's algorithms are used for the inverse Laplace transform. The numerical calculations are carried out with the help of Mathcad software, and the results are illustrated graphically. It has been found that the memory effects have a significant influence on the motion of the fluids. Keywords n-layered immiscible fluids • Fractional second grade fluids • Analytical and semi analytical solutions • Integral transforms Mathematics Subject Classification 76-XX • 76T30 • 76D50 Nomenclature i Density i Dynamic viscosity i Kynamic viscosity u 0 Characteristic velocity G i Elastic modulus i Shear stress u i (y, t) Velocity P Pressure h Distance between two plates X (y,) Laplace transform of the function X(y, t) E i , i (⋅) Mittag-Leffler function G 1 , 2 , 3 (t,) G-Lorenzo Hartely function

The protection of power system is an essential trait in a huge network to efficiently detect and isolate the sections undergoing faults or abnormal behaviour. The key components of a protection scheme include circuit breakers, relays, switchgears and fuses which employ communication from one station to another to achieve high-speed tripping. The automation of these components at the laboratory level using programmable logic controller (PLC) along with supervisory control and data acquisition (SCADA) system owns paramount importance for intelligent decision making, sensing, actuating, monitoring and maintaining the record in the host server. This paper discusses such a technique for conventional power system protection laboratory at a new level of development to promote a control system through PLC and SCADA. The control system has indication of over and under values of voltage, load and frequency, which can trigger malfunctioning of equipment and must be rectified. Furthermore, ground fault and inverse current indication are added to the system for monitoring and controlling purposes. The proposed system enhances the efficiency and safety of the expensive equipment and the personnel to the next level and also introduces new standards of automated protection schemes for modern technical institutes.

When the universal-input applications are dealt with the power-factor-correction (PFC), there is always the problem of higher switch voltage stresses and higher inductor conduction losses. The paper has a topology namely buck-interleaved buckboost (BuIBB) converter has lower switch voltage stresses and lower inductor conduction losses compared to other single-switch or two-switch converter topologies. In the paper, the analysis of the converter operation, component stresses and the total rootmean-square (RMS) currents is shown.

The major shortcoming in the extraction of electrical energy occurs due to partial shading over a limited area of vast spread solar panels underpinning reduction of efficiency. A number of panels are interconnected in series and parallel to form a photovoltaic (PV) array for large power plants and a shadow over a single cell deteriorates overall performance. As a consequence, several peaks are added to the P-V curve causing hotspots in PV panels, degradation of the PV system, and collapse of tracking algorithms. In order to minimize such issues in PV panels, an effective optimization technique is developed by reconfiguring the panels which are capable of reaching the full global power point in a PV system under partial shading conditions. The study proposes particle swarm optimization (PSO) using PV characteristics of Quaid-e-Azam Solar Plant (QASP) in Punjab, Pakistan1. In PSO, electrical connections of PV modules are changed keeping their physical locations unaltered aiming to improve the performance of the PV system. After reconfiguration, the algorithm finds the best combination of PV modules by equalizing the row currents followed by the comparison of row current, voltages, and power of panels. The proposed PSO is proved to be an efficient method for reconfiguring PV modules in very less computational time by increasing the output power of shaded modules.