Nayak A.,Silicon Institute of Technology |
Dash G.C.,Soa University
Journal of Engineering Thermophysics | Year: 2015
In this paper, the problem of transient hydromagnetic flow of an electrically conducting couple stress fluid in a rotating frame of reference through a saturated porous channel under the influence of pulsatile pressure gradient is presented. The novelty of the proposed work is to analyze the effect of couple stress as well as the case of steady and pulsatile pressure gradient on a flow through a porous saturated rotating channel. Further, the discussion on steady and pulsatile pressure gradient has made the study interesting. It is noteworthy to remark that the presence of pulsatile pressure gradient has rendered the secondary flow to be positive where as in case of steady pressure gradient it is all through negative for all cases. Further, the strong magnetic interaction and higher rotation initiate flow instability in the central region of the channel. Moreover, greater magnetic interaction contributes to smoothness of the profile and oscillatory pressure gradient increases the secondary velocity preventing backflow,which are beneficial toMHD rotating generator system. © 2015, Pleiades Publishing, Ltd.
Ranjan R.,Kolhan University |
Kumar R.,Kolhan University |
Kumar N.,Indian Institute of Technology Kharagpur |
Behera B.,Sambalpur University |
Choudhary R.N.P.,Soa University
Journal of Alloys and Compounds | Year: 2011
The polycrystalline ceramic samples of Pb1-xSm x(Zr0.55Ti0.45)1-x/4O3 (x = 0.00, 0.03, 0.06 and 0.09) were prepared by solid-state reaction technique at high temperature. Electric impedance (Z) and modulus (M) properties of the materials have been investigated within a wide range of temperature and frequency using complex impedance spectroscopy (CIS) technique. The complex impedance analysis has suggested the presence of mostly bulk resistive (grain) contributions in the materials. This bulk resistance is found to decrease with the increase in temperature. It indicates that the PSZT compounds exhibit a typical negative temperature coefficient of resistance (NTCR) behavior. The bulk contribution also exhibits an increasing trend with the increase in Sm 3+ substitution to PZT. The complex modulus plots have confirmed the presence of grain (bulk) as well as grain boundary contributions in the materials. Both the complex impedance and modulus studies have suggested the presence of non-Debye type of relaxation in the materials. © 2011 Elsevier B.V. All rights reserved.
Pradhan D.K.,National Institute of Technology Rourkela |
Behera B.,Sambalpur University |
Das P.R.,Soa University
Journal of Materials Science: Materials in Electronics | Year: 2012
A polycrystalline ceramic with a new type of complex tungsten-bronze type structure, having a general formula K 2Ba 2Nd 2Ti 4Nb 4W 2O 30 has been prepared using a high temperature solid-state reaction route after optimizing the calcinations conditions on the basis of thermal analysis results. The material has been characterized by different experimental techniques. The formation of the compound has been confirmed using X-ray diffraction analysis. Dielectric properties (ε r and tanδ) of the compound as a function of temperature at different frequencies have been carried out. Temperature dependence of dielectric constant indicates the presence of ferroelectric phase transition well above the room temperature. Complex impedance spectroscopic analysis has been carried out as a function of frequency at different temperatures to establish some correlation between the microstructure and electrical properties of the material. The nature of frequency dependence of ac conductivity obeys the Jonscher's power law. The dc conductivity calculated from the ac conductivity spectrum shows the negative temperature coefficient of resistance behavior like a semiconductor. © Springer Science+Business Media, LLC 2011.
Mishra M.,Soa University |
Rout P.K.,Electrical Engineering from BijuPattanik University of Technology
International Review of Electrical Engineering | Year: 2016
This paper presents a novel technique based on time-frequency analysis to detect the islanding conditions in distribution network with the presence of multiple distributed generations (DGs). Various islanding and non-islanding fault conditions such as capacitor switching, load rejection and line to line fault etc., are analyzed through negative sequence decomposition technique. Feature extraction has been carried out by two time-frequency analysis techniques based on wavelet transform (WT) and S-Transform (ST). For the detection of various disturbances the energy and standard deviation (SD) features of signals are estimated by wavelet transform coefficient and S-transform matrix. Furthermore, based on the estimated features the artificial neural network (ANN) and support vector machine (SVM) are used as a classifier to classify the islanding and non-islanding events. For showing the effectiveness of the proposed technique to detect islanding conditions under a wide range of operating environment, some simulated results are presented. © 2016 Praise Worthy Prize S.r.l. - All rights reserved.
Pravat K.R.,Brm International Institute Of Technology |
Dash G.C.,Soa University |
Ajit K.P.,Un Autonomous College
Proceedings of the National Academy of Sciences India Section A - Physical Sciences | Year: 2010
Effect of Hall current on the unsteady free convection flow of an electrically conducting incompressible viscous fluid past an exponentially accelerated vertical porous flat plate with internal heat absorption/generation in the presence of foreign gases (such as H2, CO2, H 2O, NH3) and chemical reaction has been investigated. An uniform magnetic field transverse to the plate has been applied. The effects of the Hall current m, the hydromagnctic parameter Mt, the chemical reaction parameter Kc the Grashof number for heat transfer Gr, the Grashof number for mass transfer G , the Schmidt number Sd the Prandtl number P and the transpiration parameter a are discussed in detail.