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Study on effect of welding speed on friction stir welded aluminium metal matrix hybrid composite
P. Gopi Krishnan,B. Suresh Babu,S. Madhu,S. J. Gowrishankar,C. Bibin,S. Saran,S. Shree Ram,A. R. Sri Hari,S.Vidyasagar 한양대학교 세라믹연구소 2021 Journal of Ceramic Processing Research Vol.22 No.5
The development of aluminum series matrix hybrid composites with ceramic reinforcements has recently caught the interestof new researchers. The addition of more than one or two reinforcements in aluminium alloy leads to the fabrication of theAluminium Metal Matrix Hybrid Composite (AMMHC). The present investigation is aimed at the development of newlydeveloped AMMHC followed by friction stir welding for obtaining the improved mechanical properties. The stir castedAA6063 with reinforcement of 5%, 10% and 15% wt. Silicon Carbide (SiC) and 10% wt. Boron Carbide (B4C) werefabricated by stir casting technique and the AMMHC with 10% each of SiC and B4C showed higher mechanical properties. Further the AMMHC are joined by friction stir welding (FSW) route. A prime experimental work has been tried out in theFSW process by varying welding speed (20, 30, 40, 50 and 60 mm/min). The effect of welding speed on AMMHCs were studiedon macro and microstructural observations followed by micro hardness and ultimate tensile. Strength, in which 40 mm/minof welding speed gives better properties than other processing condition. The weldment reveals the better joint strength withthe presence of fine particle dispersion in the microstructure.
Periodic Virtual Hierarchy: A Trust Model for Smart Grid Devices
Arezou Moussavi-Khalkhali,Ram Krishnan,Mo Jamshidi 보안공학연구지원센터 2016 International Journal of Security and Its Applicat Vol.10 No.11
Authentication among various devices that form a smart grid is a fundamental issue. Due to the large-scale, distributed, and heterogeneous nature of a smart grid, authenticating devices based on their credentials such as secret keys is often not practical. Alternatively, certificate-based trust relationships can facilitate interactions in such scenarios. Two pivotal trust relationship models, hierarchical and peer-to-peer, have been well-researched in the literature. However, the devices in a smart grid do not benefit exclusively from a single trust relationship model owing to the heterogeneous nature of its control structure. In this paper, we propose a periodic hierarchical trust relationship model suitable for real-time applications in a smart grid and robust to the single point of failure problem, which is common in hierarchies. The proposed model deploys a two-layer security authentication mechanism among different devices within those domains in which there are control hierarchies using short-term and long-term certificates, the latter of which is verified periodically.
Senthilkumar Vellur,Parasuraman Pavadai,Sureshbabu Ram Kumar Pandian,Chandrasekar Palanichamy,Shanmugampillai Jeyarajaguru Kabilan,Krishnan Sundar,Suthendran Kannan,Selvaraj Kunjiappan 한국식품과학회 2024 Food Science and Biotechnology Vol.33 No.2
This study was designed to optimize the ultrasound-assisted extraction (UAE) of bioactive chemicals from Hemidesmus indicus (L.) R.Br. through RSM (response surface methodology) and ANFIS (adaptive neuro-fuzzy inference system). The effect of four independent parameters, methanol concentration (X1: 55–65%), temperature (X2: 30–40 °C), time (X3: 15–20 min) and particle size (X4: 0.5–1.00 mm) at five levels (− 2 ,− 1, 0, + 1, + 2) with respect to dependent parameters, total polyphenols content (TP) (y1), total flavonoids content (TF) (y2), %DPPHsc (y3), %ABTSsc (y4) and %H2O2sc (y5) were selected. The optimal extraction condition was observed at X1 = 65%, X2 = 40 °C, X3 = 20 min and X4 = 0.5 mm; under this circumstance, y1 = 352.85 mg gallic acid equivalents (GA)/g, y2 = 300.204 mg rutin equivalents (RU)/g and their antioxidant potentials (y3 = 81.33%, y4 = 65.04%, and y5 = 71.01%) has been attained. ANFIS was used to compare and confirm the optimized extraction parameter values. Further, GC–MS and LC–MS were performed to investigate the bioactive chemicals present in the optimized extract.