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: Computer science & Corrosion. The organization has 5017 authors who have published 7057 publications receiving 70367 citations.

Effect of Power Input on Metallurgical and Mechanical Characteristics of Inconel-625 Welded Joints Processed Through Microwave Hybrid Heating

Abstract: In the present study, welding of Inconel-625 through the use of microwave hybrid heating (MHH) has been achieved at two power levels 600 W and 900 W in a low-cost home microwave oven. Nickel-based powder EWAC was used as filler interface between faying surfaces. Effect of power variation on the metallurgical and mechanical characteristics of the microwave welded joints has been investigated. Developed joints were characterized through XRD, optical microscope, SEM, universal testing machine and Vickers microhardness tester. XRD study of the weld zone indicated the formation of various carbides and intermetallics. Joint microstructures witnessed a completely fused weld interface without any interfacial cracks. EDS analysis of the joint microstructure revealed lesser amount of segregation of niobium and molybdenum with the specimens developed at 600 W which could be attributed to the lower heat input associated with 600 W power that also resulted in fine grain structure. Further, the specimens processed at 600 W exhibited better tensile and flexural properties when compared to their counterparts produced at 900 W power. Fractography study of the specimens revealed a combined ductile and brittle fracture.

Evaluation of optimal parameters of MR fluids for damper application using particle swarm and response surface optimisation

Abstract: The controllable rheological properties of MR fluid exhibit viscoelastic properties within pre-yield, which are essential for the characterization of MR dampers for the isolation of vibration. In the present work, using particle swarm optimisation (PSO), it is identified that the proportion of MR fluid constituents, fluid gap and current are the parameters which influence majorly on the rheological properties and damping effect of MR damper. Initially, rheological properties of the prepared MR fluid samples are determined using rotational plate–plate type rheometer with the magnetorheological device cell attachment by keeping three levels of gap between the parallel plates. Three different proportions of MR fluid are prepared based on the volume fraction of carbonyl iron particle, i.e., 25, 30 and 35% in the silicone carrier fluid along with 1% of lithium-based grease as stabiliser. The objective function of this optimisation problem is to maximise the shear stress and damping force of the MR damper. The design of experiment (DOE) is employed to obtain the various combinations of parameters and their respective responses. The interaction of the regression model obtained from the DOE is used in PSO to evaluate the optimal parameters. The results indicated that the MR fluid with the particle concentration of 31% is the optimal proportion for MR damper application.

Enhanced mobility aware routing protocol for Low Power and Lossy Networks

Abstract: Due to the technological advancement in Low Power and Lossy Networks (LLNs), sensor node mobility becomes a basic requirement for many extensive applications. Routing protocol designed for LLNs must ensure real-time data transmission with minimum power consumption. However, the existing mobility support protocols cannot work efficiently in LLNs as they are unable to adapt to the change in the network topology quickly. Therefore, we propose an Enhanced Routing Protocol for LLNs (ERPL), which updates the Preferred Parent (PP) of the Mobile Node (MN) quickly whenever the MN moves away from the already selected PP. Further, a new objective function that takes the mobility of the node into an account while selecting a PP is proposed. Performance of the ERPL has been evaluated with the varying system and traffic parameters under different topologies similar to most of the real-life networks. The simulation results showed that the proposed ERPL reduced the power consumption, packet overhead, latency and increased the packet delivery ratio as compared to other existing works.