Earticle

Time delays are inherent in process industry. The presence of time delays limits and degrades the possible performance of the system and also leads to instability. The states of the delay system not only depend on the present state, they also depend on the previous states. With the help of a suitable controller design, the delay systems can be controlled for getting fruitful results. In all industrial feedback control applications most commonly and practically used controllers are Proportional Integral Derivative (PID) controllers. With proper parameter tuning of the controller, required performance can be achieved from the system. In general, the first order processes with time delay can be easily controlled with PI controllers. By choosing the proper controller gains the effect of time delays can be avoided. In this paper, PI controller design with Lambert W function analysis in smith configuration has been proposed. After the selection of dominant poles, the PI controller gains were chosen accordingly to shift the desired eigen values to required positions using the Lambert W function based analysis. A first order process with time delay has been considered in this paper and the comparative analysis of proposed tuning algorithm with Smith predictor (SP) and Zeigler-Nichols (ZN) methods has been done. By using the time response performance specifications and errors, the performance of different tuning algorithms has been analyzed. From the simulation and different performance indices results, it has been observed that proposed smith configured Lambert W based controller tuning approach gives improved results compared to remaining methods in terms of the measures like overshoot, peak time, settling time, rise time, errors etc.

Concentrations of natural radionuclides 226Ra, 232Th and 40K as well as the radiological hazard parameters were calculated in the marine sediments in three regions in Quseir city along the Red Sea coast; El-Edua area, Phosphate Harbour and north Flaminko Village. The average activity concentrations of 226Ra, 232Th and 40K at El-Edua area were, 24.9±3, 19.6±2.4 and 234.5±43 Bq.kg-1 and at Quseir Harbour recorded the average activities concentrations were; 26.2±3.2, 19.4±2.8 and 458.6±164.2 Bq.kg-1 while at north Flaminko Village found to be; 25.7±6.9, 22.6±5 and 106.4±17.5 Bq.kg-1 respectively in Quseir city, Egypt. Concentrations of the metals; Mn, Zn, Cu, Pb, Ni, Co and Cd were determined by Atomic Absorption Spectrophotometry (AAS) using GBC-932ver.1.1with detection limits of 0.01 ppm.

This paper proposes a three phase nine level inverter with various three phase star (Y) connected loads of R (Resistive) load, RL (Resistive Inductive) load and IM (Induction Motor) load. The various PWM (Pulse Width Modulation) control techniques were proposed. Motor load provides rated speed N (rpm) and its corresponding electromagnetic torque T (N-m). Pulse Disposition (PD) technique provides better Total Harmonic Distortion (THD) and rated speed for this proposed topology. Performance factors are like VRMS, VPEAK, IRMS, IPEAK (fundamental), THD were obtained and its FFT plots are analyzed and presented. Simulations were performed using MATLAB – SIMULINK. Simulation results such as output voltage, output current and speed torque characteristics are shown. Carrier Overlapping (CO) PWM is found to execute relatively higher fundamental RMS component.

The present work aims to investigate the potential of Coriandrum sativum L. seed as a low-cost bio-sorbent for the removal of Zn (II) ions from aqueous medium. It is available as a major waste in food flavoring industries including bakery and confectionery as well as laboratories of traditional medicines. Adsorption of Zn (II) on to Coriandrum sativum L. seed has been investigated after optimizing the experimental parameters, namely, pH, contact time, adsorbent and Zn(II) concentrations and temperature. The characterization was done with Fourier transform infra red spectroscopy for examining the possible interacting sites of the adsorbent. Important isotherm models, namely Langmuir, Freundlich and Dubinin--Radushkevich models have been studied. The spontaneous nature of adsorption is indicated by the observed thermodynamic parameters. The adsorption process was found to follow pseudo-first order kinetic model and also followed the intraparticle diffusion up to 50 minutes of contact time. It was found to retain 98% of the sorption capacity up to 3 cycles of adsorption and elution. Hence, the proposed method offers a very simple, low cost, effective and eco-friendly alternative methodology for waste valorization and extraction of metal ions from wastewater.

This paper presents a Bat Algorithm (BA) for solving economic emission dispatch (EELD) problem with quadratic fuel function. The BA is a new meta-heuristic algorithm which is a powerful optimal solution search algorithm owing easily selected control parameters and high successful rate as well as high ability for dealing with complex constraints. In addition to minimizing electricity generation fuel cost, emission released into the air from thermal plants is also another main objective needs to be minimized. In order to test the performance of the proposed BA one system with two load cases is employed. The obtained result by the BA compared to that from other methods has revealed that the proposed BA is a very promising meta-heuristic algorithm for solving economic emission load dispatch problem.

In this study we analyzed the momentum, heat and mass transfer behaviour of magnetohydrodynamic flow towards a vertical rotating cone in porous medium with thermophoresis and Brownian motion effects. Further, the numerical solutions are elucidated by using Runge-Kutta based shooting technique. Obtained results are validated with open literature and found an excellent agreement. The influence of non-dimensional governing parameters on velocity, temperature and concentration profiles along with the skin friction factor, local Nusselt and Sherwood numbers are determined and discussed with the help of graphs and tables. Results proved that the thermophoresis and Brownian motion parameters have tendency to control the heat and mass transfer rates. It is also found that a raise in the porosity parameter develops the heat and mass transfer rate.