National Institute of Technology, Karnataka

About: National Institute of Technology, Karnataka is a education organization based out in Mangalore, Karnataka, India. It is known for research contribution in the topics: Corrosion & Cloud computing. The organization has 5017 authors who have published 7057 publications receiving 70367 citations.

Large‐scale advection of continental aerosols during INDOEX

Abstract: In this paper, we present passive and active remote sensing measurements of atmospheric aerosols over the North Indian Ocean (NIO) during the Intensive Field Phase (IFP, January to March 1999) of the Indian Ocean Experiment. The variability of the aerosol load over NIO is discussed based on three-dimentional numerical simulations made at a local scale by use of Regional Atmospheric Modeling System (RAMS) and at a regional scale using the zoomed Laboratoire de Meteorologie Dynamique global circulation model (LMD-Z version 3.3). Ground-based measurements of the columnar aerosol optical thickness (AOT) and of surface black carbon (BC) concentration were carried out at two different sites in India: Goa University on the NIO coast and Dharwar 150 km inland. Local-scale investigations point out that the trend in BC concentration at the ground is not correlated with AOT. Lidar profiles obtained both from the surface at Goa and in the NIO from the Mystere-20 research aircraft indicate that a significant contribution to the total AOT (more than 50%) is due to a turbid monsoon layer located between 1 and 3 km height. RAMS simulation shows that the advection of aerosols in the monsoon layer is due to the conjunction of land-sea breeze and topography. We present the regional-scale extent of the aerosol plume in terms of AOT derived from the visible channel of Meteosat-5. During March, most of the Bay of Bengal is overcast by a haze with a monthly average AOT of 0.61±0.18, and a spatially well-defined aerosol plume is spreading from the Indian west coast to the Intertropical Convergence Zone with an average AOT of 0.49±0.08. Those values are bigger than in February with AOT at 0.35±0.18 and 0.37±0.09 for the Bay of Bengal and the Arabian Sea, respectively. One of the principal findings of this paper is that a significant contribution to the aerosol load over the NIO is due to the advection of continental aerosols from India in a well-identified monsoon layer above the marine boundary layer. Moreover, it is suggested that the increase in biomass burning plays a significant role in the increasing trend in AOT during the winter dry monsoon season.

Design and Implementation of a Sensorless Multilevel Inverter With Reduced Part Count

Abstract: This letter proposes a single-phase nine-level (9L) inverter topology suitable for grid-connected renewable energy systems. The proposed inverter is realized using a T-type neutral-point-clamped inverter connected in cascade to a floating capacitor (FC) H-bridge. Additionally, two low-frequency switches are added across the dc-link enabling the inverter to generate a 9L waveform. A sensorless voltage control based on redundant switching state is developed and embedded with PWM controller, which is responsible for regulating the FC voltage at one-quarter of the dc source voltage. The proposed PWM technique employs the generation of 9L waveform without using any voltage sensor, thereby reducing the complexity of the overall control scheme. This, in turn, will make the overall system appealing for various industrial applications. In comparison to conventional and recent topologies, generation of the 9L waveform using a lower number of components is the notable contribution. Another important feature of the proposed inverter is that if FC H-bridge fails, it can be bypassed, and the inverter can still operate as a 5L inverter at its nominal power rating. Furthermore, a comprehensive comparison study is included which confirms the merits of the proposed inverter against those of other state-of-the-art topologies. Finally, simulation and experimental results are included for validating the feasibility of the proposed system.

Modeling of photovoltaic system for uniform and non-uniform irradiance: A critical review

Abstract: A critical review on various modeling approaches of photovoltaic array both under uniform and non-uniform irradiance is presented in this paper. The main approaches that have been deliberated are based on the variation of analytical methods, classical optimization techniques and soft computing techniques. The review has been taken from papers published up to 2015. In this paper a detailed description and classifications of modeling techniques for both uniform and non-uniform irradiance conditions are presented. Modeling of PV systems under uniform irradiance is classified into non-iterative methods, iterative methods, artificial intelligence based methods and dynamic models. Under non-uniform irradiance, they are classified into non-iterative methods, iterative methods and artificial intelligence based methods. It is envisaged that this paper can serve as valuable information for researchers to work on photovoltaic array modeling under partial shaded condition.