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: Computer science & Control theory. The organization has 1138 authors who have published 1381 publications receiving 7798 citations.

Bioethanol production from cereal crops and lignocelluloses rich agro-residues: prospects and challenges

Abstract: The existing energy demand, fluctuating oil prices and repercussions due to usage of fossil fuels have enhanced the requirement for alternative energy sources. Bioethanol derived from cereal crops serve as a promising alternative to conventional gasoline owing to the advantages of feedstock availability, reduction in production costs coupled with significant low greenhouse gas emissions. Recent studies focused on agro-residues derived from cereal crops had illustrated potential technical advantages for bioethanol production. Conventional bioethanol process includes pretreatment, saccharification and fermentation. Unlike acid and base pretreatment methods, enzymatic and ionic liquid pretreatment methods showed promising results in delignification process. Besides, studies demonstrated that integrated processes like simultaneous saccharification and fermentation and consolidated bioprocessing showed significant reducing sugar release and higher bioethanol yield from cereal crops and their residues. Moreover, deploying advanced technologies such as genome editing and metabolic engineering techniques could not only enhance bioethanol content but also helps in development of biorefinery theme, which leads to development of inexpensive technology. These studies and know-how technologies imply that the cereal crops and their residues could be viable substrates for bioethanol production that ultimately bolster the energy security.

A Novel Multi-Criteria Channel Decision in Co-operative Cognitive Radio Network Using E-TOPSIS

Abstract: In this paper, a novel multi-criteria channel decision model is developed by using the Enhanced Technique for Order Preference by Similarity to Ideal Solution (E-TOPSIS). The proposed model achieves some desirable features that enable channel decision makers to construct complex decision-making problems. It considers multiple factors of each channel and node, thus the channel allocation and sharing in an effective manner. Given novel model provides an effective methodology for cooperative model of CRN (Cognitive Radio Network) and its channel decision making process with cost effective and accuracy. It is well known that the cooperative spectrum sensing has advantage in handling large tasks with less complexity and Protects from fading and shadowing. The proposed model implemented and analyzed well with multilevel comparison.

A DCCII based square wave generator with grounded capacitor

Abstract: A new square wave generator is proposed using second generation differential current conveyor (DCCII). The proposed circuit has single DCCII and three passive components viz, two resistors and a single capacitor. The grounded capacitor feature has made in implementing a proposed waveform generator. Proposed circuit offers electronic tunability of its duty cycle, operating in wide range frequency from a few Hz to few MHz and also has improved linearity. Comparison of proposed circuit features in contrast to existing oscillator circuits are tabulated with relevant discussion and description mentioning prominent significances. Design and simulation is done in Cadence Virtuoso using gpdk 180 nm libraries. AD844AN commercial op-amps are used for experimental validation of the proposed model.

Effect of Grain Refinement on Corrosion Rate, Mechanical and Machining Behavior of Friction Stir Processed ZE41 Mg Alloy

Abstract: The aim of the present work is to modify the microstructure of ZE41 Mg alloy by friction stir processing (FSP) and to study the influence of microstructure on the corrosion, mechanical and machining behavior. Microstructural observations revealed the prevalence of grain refinement from ≈ 100 to 3.5 µm. The compound present at the grain boundary was observed to have decreased to a great extent after FSP suggesting the formation of supersaturated grains. Hardness measurements indicated increased hardness after FSP which was attributed to grain refinement effect. Tensile tests showed increased yield strength after FSP without altering the percentage of elongation which was due to the grain boundary strengthening. Corrosion performance of FSPed ZE41 was found to be similar compared with ZE41 due to the synergy of grain refinement, decreased amount of secondary phase and development of supersaturated grains. Grain size was observed as significant factor on machining characteristics as observed from improved machinability for FSPed ZE41 during drilling experiments. It was learnt from the current work that the grain-refined supersaturated ZE41 Mg alloy could be produced through FSP with better mechanical and machining behavior without deteriorating the corrosion performance.