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.

Landslide Susceptibility Zonation Mapping: A Case Study from Darjeeling District, Eastern Himalayas, India

Abstract: Landslides have been one of the most damaging natural hazards in the hilly region, which cause loss of life and infrastructure, and hence, landslide susceptibility zonation (LSZ) maps are inevitable for the pre-identification of vulnerable slopes and for the future planning and mitigation programmes. In this study, an integrated remote sensing and geographic information system approach is adopted for the generation of LSZ Map for the Darjeeling and Kalimpong district, West Bengal, India. Topographic maps, satellite data, other informative maps and statistics were utilized. For this study, the causative factors which cause instability of slope such as drainage, lineament, slope, rainfall, earthquake, lithology, land use, geomorphology, soil, aspect and relief were considered. For the generation of LSZ map, thematic data layers were evaluated and generated by assigning appropriate numerical values for each factor weight and their corresponding class rating in the GIS environment. Resulting LSZ map outlines the total study area into five different susceptibility classes: very high, high, moderate, low and very low. This study also demonstrates the classification and prediction of landslide-susceptible zones in coalition with GIS output by using particle swarm optimization–support vector machine approach without feature selection and ant colony optimization approach with feature selection along with support vector machine classifier. GIS-based LSZ map was validated by comparing the landslide frequencies in between the susceptible classes. The usefulness of the LSZ map was also validated by the statistical Chi-square test.

Perspectives on Nickel Hydroxide Electrodes Suitable for Rechargeable Batteries: Electrolytic vs. Chemical Synthesis Routes.

Abstract: A significant amount of work on electrochemical energy storage focuses mainly on current lithium-ion systems with the key markets being portable and transportation applications. There is a great demand for storing higher capacity (mAh/g) and energy density (Wh/kg) of the electrode material for electronic and vehicle applications. However, for stationary applications, where weight is not as critical, nickel-metal hydride (Mi-MH) technologies can be considered with tolerance to deep discharge conditions. Nickel hydroxide has gained importance as it is used as the positive electrode in nickel-metal hydride and other rechargeable batteries such as Ni-Fe and Ni-Cd systems. Nickel hydroxide is manufactured industrially by chemical methods under controlled conditions. However, the electrochemical route is relatively better than the chemical counterpart. In the electrochemical route, a well-regulated OH− is generated at the cathode forming nickel hydroxide (Ni(OH)2) through controlling and optimizing the current density. It produces nickel hydroxide of better purity with an appropriate particle size, well-oriented morphology, structure, et cetera, and this approach is found to be environmentally friendly. The structures of the nickel hydroxide and its production technologies are presented. The mechanisms of product formation in both chemical and electrochemical preparation of nickel hydroxide have been presented along with the feasibility of producing pure nickel hydroxide in this review. An advanced Ni(OH)2-polymer embedded electrode has been reported in the literature but may not be suitable for scalable electrochemical methods. To the best of our knowledge, no such insights on the Ni(OH)2 synthesis route for battery applications has been presented in the literature.

Extraction of bioactive compounds from Psidium guajava and their application in dentistry

Abstract: Guava is considered as poor man’s apple rich in phytochemicals with medicinal value and hence it is highly consumed. Gas chromatography–mass spectroscopy (GC–MS) analysis of guava leaf extract revealed the presence of various bioactive compounds with antimicrobial, antioxidant, anticancer, and antitumor properties. Hence, it is used in tooth paste formulations along with other ingredients such as Acacia arabica gum powder, stevia herb powder, sea salt, extra virgin coconut oil, peppermint oil in the present study. Three formulations F1, F2 and F3 have been made by varying the concentration of these ingredients and the prepared formulations were studied for their antimicrobial activity and physico-chemical parameters such as pH, abrasiveness, foaming activity, spreading and cleaning ability. Among these, F3 showed significant antioxidant and antimicrobial properties, minimal cytotoxicity, maximum spreadability and very high cleaning ability. This study surmises that the herbal toothpaste formulation is greener, rich in medicinal values and imparts oral hygiene.

Parametric study of the proton exchange membrane fuel cell for investigation of enhanced performance used in fuel cell vehicles

Abstract: This study focuses on the parametric analysis of Proton Exchange Membrane Fuel Cells (PEMFC) to enhance its performance used in Fuel cell vehicles. The study involves fabrication of membrane electrode assembly at 40% Pt/C loading and experimenting with different parameters, viz, cell temperatures, oxygen and hydrogen flow rates and cathode and anode humidification temperatures. The results show that cell temperature has significant effect on the performance of the PEMFC, whereas other parameters produce variation only in the activation polarization region and in the concentration polarization region. A prototype model of FCV, indigenously powered by a fuel cell stack and run continuously without any auxiliary power supply is developed as a viable model for a higher power vehicle. The vehicle’s performance is studied by conducting various load tests.
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