National Institute of Technology, Meghalaya

About: National Institute of Technology, Meghalaya is a education organization based out in Shillong, India. It is known for research contribution in the topics: Control theory & Electric power system. The organization has 503 authors who have published 1062 publications receiving 6818 citations. The organization is also known as: NIT Meghalaya & NITM.

Risk Priority Number for Bridge Failures

Abstract: One of the important and systematic methods that is used for the identification of failure of any system is the failure mode and effect analysis (FMEA). This is carried out through the iden...

Drag and Lift Characteristics of a Novel Elliptical-Bladed Savonius Rotor With Vent Augmenters

Abstract: Savonius rotor, a class of drag-driven vertical axis wind turbine, has been extensively investigated mainly to calculate the torque and power coefficients (CT and CP) by various investigators. Hitherto, studies related to lift and drag characteristics are very few and have mainly been restricted to a semicircular-bladed rotor. A deeper investigation into the drag and lift coefficients (CD and CL) can result in the better design of rotor blades leading to an increment in CT and CP. In view of this, in the present investigation, CD and CL of an elliptical-bladed rotor with vent augmenters have been studied numerically. Initially, two-dimensional (2D) unsteady simulations using an ansys fluent solver is carried out to estimate the instantaneous CD and CL. The shear stress transport (SST) k–ω turbulence model is selected to solve the Reynolds averaged Navier Stokes (RANS) equations. Finally, three-dimensional (3D) unsteady simulations are carried out for the vented elliptical-bladed rotor. The unsteady simulations are performed for the nonvented elliptical- and semicircular-bladed rotors at the identical condition in order to have a direct comparison. From the unsteady simulations, the average CD for the vented elliptical profile is found to be 1.45; whereas, the average CD for the nonvented elliptical and semicircular profiles is found to be 1.43 and 1.35, respectively.

An experimental study of cutting forces and temperature in multi-tool turning of grey cast iron

Abstract: Simultaneous machining by two single point cutting tools can enhance the productivity of the turning process. The present investigation utilises an additional cutting tool, placed opposite to the conventional cutting tool. It is an asynchronous turning process, as each tool is machining at different locations at the same time. A piezoelectric dynamometer and an infrared camera were used to measure the cutting force and cutting temperature. Machining was carried out with two single point cutting tools at various distances between them, different cutting speeds and depths of cut. The objective of this work is to investigate experimentally the effect of the distance between the cutting tools on the cutting forces, feed forces and work material temperature during multi-tool turning process. It was observed that the temperature rise in the workpiece caused due to front and rear cutting tool remained uninfluenced by the distance between the cutting tools. At some conditions, the rear cutting tool experiences lesser force compared to front tool, which may be due to reduced friction. At other conditions, there was no significant difference between the forces on front and rear cutting tools. Overall, machining performance was good and similar to that of single tool machining.

An Adaptive Current Control Technique in Grid-tied PV System with Active Power Filter for Power Quality Improvement

Abstract: This study proposes an adaptive second order generalized integrator based quadrature signal generator-frequency locked loop (SOGI-QSG-FLL) and fuzzy tuned proportional integral (FPI) in grid interconnection of photovoltaic (PV) system with shunt power quality conditioner (SAPF) for quality of power enhancement. The SOGI-QSG-FLL adaptive controller is simple in structure, more flexible, and it has been utilized for many applications like grid synchronization, frequency estimation, and harmonic extraction. The FPI voltage controller is used to stable DC bus voltage at a reference value. The combination of both controllers gives a better performance at steady state, dynamic load, grid voltage unbalancing, voltage fall, deformed voltage, raises voltage, and eliminated load states. The frequency locked loop (FLL) used for frequency estimation; the hysteresis current controller utilized for generating PWM signals to SAPF inverter. The proposed controller executed on MATLAB/SIMULINK software platform under steady state, dynamic load, grid voltage unbalancing, sag, distorted, swell grid voltage, and load removed conditions. And the simulation results are found adequate within IEEE-519 limits.

Logic Design Using Memristors: An Emerging Technology

Abstract: This paper provides an introduction to memristor, which is considered as the fourth circuit element along with resistor, inductor and capacitor. Memristors possess some unique properties, i.e. it can change the resistance under voltage control and can retain its value even after the voltage is withdrawn. Another property of memristors is their small feature size which makes them useful for design of ultra-compact memory systems. In addition, the resistive switching property of memristors allows to execute logic primitives and thus can also be used for implementing logic functions using various logic design styles studied in this paper. The paper also discusses memristor fabrication, circuit models, methods for implementing logic functions, and the various computing methodologies that can be used viz. nearmemory computing and in-memory computing.