Browsing by Author "K, S."

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    Crime base: Towards building a knowledge base for crime entities and their relationships from online news papers
    (2019) K, S.; Santhi Thilagam, P.
    In the current era of internet, information related to crime is scattered across many sources namely news media, social networks, blogs, and video repositories, etc. Crime reports published in online newspapers are often considered as reliable compared to crowdsourced data like social media and contain crime information not only in the form of unstructured text but also in the form of images. Given the volume and availability of crime-related information present in online newspapers, gathering and integrating crime entities from multiple modalities and representing them as a knowledge base in machine-readable form will be useful for any law enforcement agencies to analyze and prevent criminal activities. Extant research works to generate the crime knowledge base, does not address extraction of all non-redundant entities from text and image data present in multiple newspapers. Hence, this work proposes Crime Base, an entity relationship based system to extract and integrate crime related text and image data from online newspapers with a focus towards reducing duplicity and loss of information in the knowledge base. The proposed system uses a rule-based approach to extract the entities from text and image captions. The entities extracted from text data are correlated using contextual as-well-as semantic similarity measures and image entities are correlated using low-level and high-level image features. The proposed system also presents an integrated view of these entities and their relations in the form of a knowledge base using OWL. The system is tested for a collection of crime related articles from popular Indian online newspapers. 2019 Elsevier Ltd
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    Hot corrosion behaviour of HVAF coatings deposited on Fe[sbnd]25Cr[sbnd]20Ni support hanger material
    (Elsevier B.V., 2024) Ramanathan, P.; Gandimani, L.; K, S.; Cadambi, S.; Hegde, S.R.
    Fe[sbnd]25Cr[sbnd]20Ni cast alloy is used as the material of construction for support hangers in fired heaters of oil refineries. These hangers support heater tubes in the fired heaters and are susceptible to hot corrosion due to Na2SO4 and V2O5 containing corrosive ash, especially when low-grade fuels are burnt. API recommends 50Cr[sbnd]50Ni cast-alloy for constructing the support hangers in highly corrosive atmospheres which, is highly expensive as well as brittle. To overcome this problem, in this work, coatings of 50Cr[sbnd]50Ni and 20Cr[sbnd]80Ni were applied on Fe[sbnd]25Cr[sbnd]20Ni substrates by HVAF process. The coatings were characterized by: Optical Microscopy, SEM-EDS Analysis, XRD Analysis, and Raman Spectroscopy. To study the hot corrosion behaviour of these coated specimens, a cyclic hot-corrosion test was carried out at 700 °C using 20 % Na2SO4–80 % V2O5 salt slurry. Along with the coated specimens, cast specimens of Fe[sbnd]25Cr[sbnd]20Ni and 50Cr[sbnd]50Ni were also subjected to the hot-corrosion test. Thus, Type-II hot corrosion behaviour of all four specimens were analyzed comparatively by weight-change measurements, cross-sectional metallography, SEM-EDS, XRD, and Raman-Spectroscopy. The Fe[sbnd]25Cr[sbnd]20Ni cast specimen displayed the least corrosion resistance. The corrosion resistance of the 50Cr[sbnd]50Ni coated specimen and the 50Cr[sbnd]50Ni cast specimen was found to be intermediate and quite comparable. 20Cr[sbnd]80Ni coated specimen recorded the best corrosion resistance. The corrosion mechanism and beneficial effects of high nickel-containing HVAF coatings against hot corrosion are presented. © 2024 Elsevier B.V.
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    Hot corrosion behaviour of mullite thermal barrier coatings for marine diesel engines
    (Elsevier Ltd, 2024) K, S.; Babu, N.; Cadambi, S.; Arya, S.B.
    Mullite's inherent qualities have made it a potential material for the application of thermal barrier coatings (TBCs) for diesel engine components. Hot corrosion at 600–800 °C can cause TBC degradation, thus significantly affecting the performance of engine components and reducing their service life. This work examines the hot corrosion behaviour of atmospheric plasma-sprayed (APS) mullite coating over NiCrAlY bond coat on mild steel substrates. The coated specimen surface was covered with a mixture of Na2SO4 (sodium sulphate) and V2O5 (vanadium pentoxide) in the form of paste and heated in a muffle furnace at 700 °C for up to 300 h. SEM, EDS, and XRD characterisations were used to investigate the mechanism of hot corrosion. Coatings remained intact after corrosion tests; however, it had reacted with corrosive salts, particularly sodium sulphate. This was evidenced by the removal of amorphous silica, followed by the formation of nosean as a major phase. During the reaction between sodium sulphate and mullite coating, vanadium pentoxide was found to be acting as a flux and mineraliser. © 2023 Elsevier Ltd and Techna Group S.r.l.