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Institution

Vignan University

EducationGuntur, Andhra Pradesh, India
About: Vignan University is a(n) education organization based out in Guntur, Andhra Pradesh, India. It is known for research contribution in the topic(s): Control theory & CMOS. The organization has 1138 authors who have published 1381 publication(s) receiving 7798 citation(s).
Topics: Control theory, CMOS, Cement, Machining, Population
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Journal ArticleDOI
Abstract: The development of highly active and stable earth-abundant catalysts to reduce or eliminate the reliance on noble-metal based ones in green and sustainable (electro)chemical processes is nowadays of great interest. Here, N-, O-, and S-tridoped carbon-encapsulated Co9S8 (Co9S8@NOSC) nanomaterials are synthesized via simple pyrolysis of S- and Co(II)-containing polypyrrole solid precursors, and the materials are proven to serve as noble metal-free bifunctional electrocatalysts for water splitting in alkaline medium. The nanomaterials exhibit remarkable catalytic performances for oxygen evolution reaction in basic electrolyte, with small overpotentials, high anodic current densities, low Tafel slopes as well as very high (nearly 100%) Faradic efficiencies. Moreover, the materials are found to efficiently electrocatalyze hydrogen evolution reaction in acidic as well as basic solutions, showing high activity in both cases and maintaining good stability in alkaline medium. A two-electrode electrolyzer assembled using the material synthesized at 900 °C (Co9S8@NOSC-900) as an electrocatalyst at both electrodes gives current densities of 10 and 20 mA cm−2 at potentials of 1.60 and 1.74 V, respectively. The excellent electrocatalytic activity exhibited by the materials is proposed to be mainly due to the synergistic effects between the Co9S8 nanoparticles cores and the heteroatom-doped carbon shells in the materials.

272 citations


Journal ArticleDOI
TL;DR: The present review describes the biosurfactants and its synthesis from bacteria and also emphases on the role of surfactants in oil remediation.
Abstract: The energy resources mainly petroleum and petroleum hydrocarbons are major pollutants of the environment. The oil and oil products contamination may cause severe harm and hence, the attention has been remunerated in the development of alternative technologies for elimination of these contaminants. Biosurfactants were used in the remediation of oil pollution due to advantages such as biodegradability and low toxicity. The biosurfactants are produced from low cost substrates like agro-industrial wastes which reduce the cost of production. Biosurfactants and bioemulsifiers are amphiphilic compounds and are produced as extracellular or a part of the cell membrane by bacteria. The insight view, how hydrocarbons are degraded by microorganisms and thereby reduce the damage of ecosystem is highly essential to target the problem. Biofilms are the bacterial communities which protects the bacterial cells from various adverse conditions. The present review describes the biosurfactants and its synthesis from bacteria and also emphases on the role of surfactants in oil remediation.

152 citations


Journal ArticleDOI
Abstract: Machining of stainless steel is difficult due to their hardening tendency. In boring of stainless steels, tool wear and surface roughness are affected by vibration of boring bar. In this paper, tool wear, surface roughness and vibration of work piece were studied in boring of AISI 316 steel with cemented carbide tool inserts. A Laser Doppler Vibrometer was used for online data acquisition of work piece vibration and a high-speed Fast Fourier Transform analyzer was used to process the acousto optic emission signals for the work piece vibration. Experimental data was collected and imported to artificial neural network techniques. A multilayer perceptron model was used with back-propagation algorithm using the input parameters of nose radius, cutting speed, feed and volume of material removed. The artificial neural network was used to predict surface roughness, tool wear and amplitude of work piece vibration. The predicted values were compared with the collected experimental data and percentage error was computed.

111 citations


Journal ArticleDOI
Abstract: We present a facile synthetic method that yields Ag@CoxP core–shell-type heterogeneous nanostructures with excellent oxygen evolution reaction (OER) activity. This nanocatalyst can deliver a current density of 10 mA/cm2 at a small overpotential of 310 mV and exhibits high catalytic stability. Additionally, the catalytic activity of Ag@CoxP is 8 times higher than that of the Co2P nanoparticles, owing primarily to the strong electronic interaction between the Ag core and the CoxP shell.

106 citations


Journal ArticleDOI
01 Oct 2014-Optik
TL;DR: The proposed antenna consisting of graphene nano ribbon as radiating patch and also the ground plane separated by a 20 μm thin polyimide substrate has achieved the broad impedance bandwidth (>5%) in the band of operation.
Abstract: Graphene nano ribbon based terahertz patch antenna on polyimide substrate is designed and its radiation characteristics are investigated in the 725–775 GHz band. The terahertz communication system consists of higher data rate transmission, low transmit power with secured wireless communication. The proposed antenna consists of graphene nano ribbon as radiating patch and also the ground plane separated by a 20 μm thin polyimide substrate. The antenna has achieved the broad impedance bandwidth (>5%) in the band of operation. The design has yielded a peak gain of 5.71dB at 750 GHz. The antenna is simulated by using the finite element method based simulator Ansys - HFSS.

90 citations


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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202213
2021352
2020254
2019250
2018159
201787