Automatic generation control of TCPS based hydrothermal system under open market scenario: A fuzzy logic approach

This paper presents the analysis of automatic generation control of a two-area interconnected thyristor controlled phase shifter based hydrothermal system in the continuous mode using fuzzy logic controller under open market scenario. Open transmission access and the evolving of more socialized companies for generation, transmission and distribution affects the formulation of AGC problem. So the traditional AGC two-area system is modified to take into account the effect of bilateral contracts on the dynamics. It is possible to stabilize the system frequency and tie-power oscillations by controlling the phase angle of TCPS which is expected to provide a new ancillary service for the future power systems. A control strategy using TCPS is proposed to provide active control of system frequency. Further dynamic responses for small perturbation considering fuzzy logic controller and PI controller (dual mode controller) have been observed and the superior performance of fuzzy logic controller has been reported analytically and also through simulation.     

Silicon (BSFR) solar cell AC parameters at different temperatures

The AC parameters of back surface field refiected (BSFR) silicon solar cell are measured at different cell temperatures (198–348 K) both in forward and reverse bias under dark condition using impedance spectroscopy technique. It is found that cell capacitance increases with temperature whereas cell resistance decreases, in forward bias voltage. Beyond maximum power point voltage, the cell inductance (0.28 μH) is measured, as the inductive reactance is comparable with cell series resistance. The measured cell parameters (cell capacitance, dynamic resistance, etc) are used to calculate the mean carrier lifetime and diode factor at different cell temperatures.     

Synthesis and characterization of ZnS-based quantum dots to trace low concentration of ammonia

In the present work,a solution-based co-precipitation method has been adopted to synthesize pure and cobalt-doped ZnS quantum dots and characterized by XRD,SEM,TEM with EDX,FTIR and gas sensing properties.XRD analysis has shown a single phase of ZnS quantum dots having a zinc blend structure.TEM and XRD line broadening indicated that the aver-age crystallite size in the sample is in the range of 2 to 5 nm.SEM micrographs show spherical-shaped quantum dots.FTIR stud-ies show that cobalt has been successfully doped into the ZnS cubic lattice.EDX spectra have analyzed the elemental pres-ence in the samples and it is evident that the spectra confirmed the presence of cobalt (Co),zinc (Zn),oxygen (O),and sulphur(S) elements only and no other impurities are observed.The ZnS-based quantum dot sensors reveal high sensitivity towards 50 ppm of ammonia vapors at an operating temperature of 70 ℃.Hence,ZnS-based quantum dots can be a promising and quick traceable sensor towards ammonia sensing applications with good response and recovery time.     

Hemophagocytic lymphohistiocytosis: An unusual presentation of tuberculosis in hemodialysis patients

We report a series of three patients with end‐stage renal disease on maintenance hemodialysis presenting with hemophagocytic lymphohistiocytosis (HLH) as an unusual manifestation of extrapulmonary tuberculosis. All three patients were middle‐aged men. They presented with fever, pancytopenia, varying degrees of hepatosplenomegaly, abnormal liver function tests, coagulopathy, increased serum ferritin, and triglycerides. Tests for fever work‐up were negative. Bone marrow examination revealed hemophagocytosis and caseating granuloma. Acid fast bacilli were demonstrated in two patients. The HLH‐2004 diagnostic criteria suggested by the histiocytic society were followed to arrive at the diagnosis. All of them succumbed to death even before the definitive diagnosis could be made. We suggest that aggressive diagnostic work‐up must be done when hemodialysis patients present with fever and pancytopenia. Priority should be toward early diagnosis and appropriate treatment to improve the prognosis.     

The effects of thermal radiation on unsteady MHD free convective flow through the porous medium between two vertical plates with Hall effects

The effects of thermal radiation and Hall current on magnetohydrodynamic free convection three-dimensional flow in a vertical channel filled with a porous medium have been studied. We consider an incompressible viscous and electrically conducting incompressible viscous fluid in a parallel plate channel bounded by a loosely packed porous medium. The fluid is driven by a uniform pressure gradient parallel to the channel plates, and the entire flow field is subjected to a uniform inclined magnetic field of strength inclined at an angle of inclination $\alpha$ with the normal to the boundaries in the transverse xy-plane. The temperature of one of the plates varies periodically, and the temperature difference between the plates is high enough to induce radiative heat transfer. The effects of various parameters on the velocity profiles, the skin friction, the temperature field, and the rate of heat transfer in terms of their amplitude and phase angles are shown graphically.