Vignan University

About: Vignan University is a education organization based out in Guntur, Andhra Pradesh, India. It is known for research contribution in the topics: Control theory & CMOS. The organization has 1138 authors who have published 1381 publications receiving 7798 citations.

On certain graph domination numbers and applications

Abstract: In this paper, we compute for paths and cycles certain graph domination invariants like locating domination number, differentiating domination number, global alliance number, etc. We also do some comparison analysis of certain parameters defined by combining the domination measures and the second smallest eigen value of the Laplacian matrix of all connected graphs of order 4. While discussing applications we have pointed out the crucial role played by graphs through its hard core structural properties in wireless sensor networks WSN.

Morphology and photoluminescence of nano-porous anodic alumina membranes obtained in oxalic acid at different anodization potentials

Abstract: Porous Anodic alumina (PAA) with highly ordered pore geometry serves as an ideal template for future development of nanodevices. In the present work, PAA was prepared by varying anodization potential from 10 to 50 V in oxalic acid at 8 °C with a constant electrolyte concentration of 0.3 M. The influence of anodization potential on the structural and photoluminescence (PL) properties of PAA has been studied. The effect of anodization potential on the main pore characteristics of PAA such as pore diameter, interpore distance, pore density, porosity and circularity was studied. It was observed that circularity of PAA was nearly equal to one in the case of anodization potential of 40 V. Highest regularity ratio (RR) obtained for PAA formed in 40 V and it was calculated by WSxM software. It was noticed that with increasing anodization potential there is a slight change in PL spectra of PAA and shows a strong PL peak in blue region.

Transient stability improvement of Microgrid using Series Active Power Filters

Abstract: The proposed Microgrid in this article has three Distributed generations namely Wind power, Fuel cells and Photovoltaic energy. Here three DG’s are connected in the form of a small power system network and interlinked with the main grid. Whenever two or more DG’s are interconnected short circuit conditions occur in the power system network at that situation fault currents are increased and voltage profiles are reduced then the system is not in stable condition. Protection of Microgrids is one of the mandatory and difficult tasks. Series active power filters (SAPF) with hysteresis controllers are considered. SAPF consists of an injection transformer, filters and voltage source inverters. The main aim of the hysteresis controller is to detect the voltage swell and voltage sag. Using this type of SAPF circuits, compensation of the voltage swell, voltage sag and reduction of the harmonics and finally transient stability of Microgrid is improved. This effort is done by means of MATLAB/Simulink software.

Highly Selective Detection of Isatin Using Curcumin Analogue and its Application in Real Samples

Abstract: A novel curcumin analogue bearing indole NH (DP4) unit was synthesized as fluorescent sensor for isatin in biological system with fairly selective over other competitors. The sensor triggered a “turn-off” fluorescence response toward isatin with concurrent decrease with fluorescence intensity in PBS buffer solution at pH 7.4. The detection limit of isatin was calculated as low as 241 nM. It can be employed to detect isatin in biological samples in buffer medium. The hydrogen bonding interaction of probe with isatin was studied using 1H NMR titration and DFT calculation.