Browsing by Author "Nayak, M."

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Drop size and rain rate characteristics of Indian monsoon rainwater
(Springer, 2023) Bhat, G.S.; Nayak, M.; Bhat, M.S.; Giri, A.V.
Abstract: Raindrops are an integral part of nature’s hydrological cycle. Information on their sizes in different seasons and climatic conditions is required in many practical applications. We report seasonal average properties of rainfall examined through raindrop sizes and rain rates measured with optical disdrometers in India. Disdrometers were operated at three sites having coastal, orographic and continental climates. Analysis has been carried out by clubbing data of each station into two groups, namely, all available and summer monsoon season-only data. The study presents contributions of different raindrop sizes and rain rates to the total rainfall. There are between 2.4 and 2.9 million raindrops (with size > 0.25 mm) in one litre of rainwater, with the orographic site having the maximum number. A sum of two exponential functions describes the size dependence of number of drops present in rainwater. Major contribution to the monsoon rainfall comes from drops having sizes in 1.5–2.5 mm range with a peak of around 2 mm. Average rain accumulation with rain rate (R) approximately varies as R–b (for R > 0); b depends on location and lies between 1.1 and 1.3, the former corresponding to the continental site while the latter to the orographic. Research highlights: There are between 2.4 and 2.9 million raindrops (with size > 0.25 mm) in one litre of rainwater. Major contribution to the monsoon rainfall comes from drops having sizes in 1.5–2.5 mm range with a peak around 2 mm. On the other hand, all values of rain rate (R) are important to rain accumulation; low rain rate contributes by its sheer number (i.e., their total long duration) while large rain rate by its magnitude. Average rain accumulation varies as R–b, where b lies between 1.1 and 1.3 depending on location. © 2023, Indian Academy of Sciences.
Performance analysis of fountain codes with Robust Soliton distribution for erasure channels
(2011) Prakash, G.; Nayak, M.; Kulkarni, M.; Shripathi, Acharya U.
Fountain Codes are essentially Forward Error Correction (FEC) codes, which were developed for applications involving multicasting or for delivering large amounts of content to multiple recipients simultaneously. FEC increases the reliability of a system in a noisy environment. Luby Transform codes (LT codes) which come from a new coding family of the Fountain codes are the first realization of rateless codes which can generate potentially limitless code words from data. In this paper, a performance analysis of Fountain codes for erasure channels, which use the Robust Soliton distribution for encoding the data packets and belief propagation to decode the received packets has been carried out Results show that the overhead during decoding is around 11.2%. � 2011 IEEE.
Performance analysis of fountain codes with Robust Soliton distribution for erasure channels
(2011) Prakash, G.; Nayak, M.; Kulkarni, M.; Sripati, U.
Fountain Codes are essentially Forward Error Correction (FEC) codes, which were developed for applications involving multicasting or for delivering large amounts of content to multiple recipients simultaneously. FEC increases the reliability of a system in a noisy environment. Luby Transform codes (LT codes) which come from a new coding family of the Fountain codes are the first realization of rateless codes which can generate potentially limitless code words from data. In this paper, a performance analysis of Fountain codes for erasure channels, which use the Robust Soliton distribution for encoding the data packets and belief propagation to decode the received packets has been carried out Results show that the overhead during decoding is around 11.2%. Â© 2011 IEEE.
Processing, Mechanical Characterization, and Electric Discharge Machining of Stir Cast and Spray Forming-Based Al-Si Alloy Reinforced with ZrO2 Particulate Composites
(MDPI, 2022) Shetty, R.; Gurupur, P.R.; Hindi, J.; Hegde, A.; Naik, N.; Ali, M.S.S.; Patil, I.S.; Nayak, M.
High performance lightweight structures made of metal matrix composites (MMCs) are in demand for application in variety of industries such as aircraft, spacecraft, automobile, marine, sports equipment, etc. However, uniform distribution of the reinforcement phase to improve the mechanical properties and quality of MMCs has been the challenge for the manufacturing industries. Hence, researchers are focusing on the development of traditional low-cost method of producing metal matrix composites. In the view of above facts, an attempt is made to study the processing and characterization of Si-Al alloy reinforced with zirconium dioxide particulate composites in this paper. Hence, this paper concentrates on experimentally identifying the effect of stir cast and spray forming processing techniques followed by hot pressing on micro hardness, compressive strength, and tensile strength using Taguchi’s design of experiments for aluminum silicon matrix alloy reinforced with zirconium dioxide particulates. From the extensive experimentation on aluminum and silicon reinforced with the ZrO2 powder particulates, it was observed that there was an improvement in selected mechanical properties as the percentage of ZrO2 increased with 13 wt.% of silicon under spray forming processing technique compared to stir cast composites. This may be due to uniform distribution homogenous dispersion, larger work hardening rate, and structure of dislocation tangles around the ZrO2 particulates that occurred during spray forming processing technique. Further, results obtained from the interaction plot, contour plot, main effects plot, and analysis of variance (ANOVA) proved to be successful for identifying the optimum processing parameters for Si-Al alloy reinforced with zirconium dioxide particulate composites. Further, this paper also discusses wear study using pin on disc wear testing apparatus on spray forming processed aluminum and silicon (13.0 wt.%) alloy reinforced with the ZrO2 powder particulates based on Taguchi’s design of experiments followed by second order model generation for wear using response surface methodology. Finally, electrode wear study of spray forming processed aluminum and silicon alloy reinforced with the ZrO2 powder particulates using electric discharge machining by varying peak current (A), pulse on time (μs), and pulse off time (μs) using brass, copper, and graphite as electrode material based on L27orthogonal array. The understanding gained from the design of experiments in this paper can be used to develop future guidelines for processing and characterization of Si-Al alloy reinforced with zirconium dioxide particulate composites. © 2022 by the authors.