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 & Computer science. The organization has 503 authors who have published 1062 publications receiving 6818 citations. The organization is also known as: NIT Meghalaya & NITM.

Wind Tunnel Experiments to Estimate the Performance of a Novel Arc-Elliptical-Bladed Savonius Wind Rotor

Abstract: The gradually exhausting non-renewable energy resources, pollution from conventional fuel resources and alarming global warming have sparked the interest in developing renewable technologies for power generation. In that connection, the vertical-axis drag-based Savonius wind turbine/rotor is an exciting prospect to harness the free energy available in the wind and can be deployed in remote areas having no electricity grids. The present study aims at designing and developing a vertical-axis Savonius wind rotor, and its subsequent testing in a wind tunnel. The key parameters affecting a Savonius rotor’s output are its blade shape, aspect ratio, overlap ratio and blade number. Considering the various aspects of blade design reported in the literature, a novel arc-elliptical-bladed Savonius wind rotor has been developed. The overlap ratio and aspect ratio are chosen to be 0.15 and 1.1:1, respectively. The testing of the rotor has been conducted in a subsonic wind tunnel under different loading conditions. The power coefficients are estimated for a range of tip-speed ratios. Further, its output characteristics have been compared with conventional semicircular-bladed Savonius rotor. The experiments reveal an improvement of 37% for arc-elliptical-bladed rotor as compared to semicircular-bladed rotor.

A general relation between supply harmonics and reactive power of an induction motor

Abstract: This paper describes the effect of inverter output voltage harmonics to the reactive power of an induction motor. The major factors responsible for reactive power have been investigated by using PQ theory, proposed by Akagi. Induction motor equivalent circuit is used here to establish a general relation between these factors and voltage harmonics fed to the motor. By this way a relation is also formed between the voltage harmonics and reactive power. To validate the proposed relation, experimental work has been done with an induction motor fed by a sine PWM inverter. Here by changing switching frequency, different types of harmonics are injected into the motor and all the factors have been investigated and compared with the proposed relation. The reactive power has been calculated by using PQ theory and net reactive power calculation method, proposed by Budeanu. A very good accuracy has been obtained between the experimental results and proposed relation.

Drilling of composite laminates using a special tool point geometry

Abstract: The traditional drilling technique is by far the most widely used hole-making operation. But this process is not very conducive when the materials to be drilled are composite laminates. The delamination of the drilled hole and cutting tool wear are few of the major challenges associated with the traditional twist drilling of composite laminates. The drilled hole quality is influenced by various parameters such as (i) tool point geometry, (ii) cutting speed, and (iii) feed rate. This chapter presents and discusses the intrinsic influence of these parameters on the hole-making performance of composite laminates. The performance parameters such as formed-chip characteristics, the behavior of cutting forces, and drilled hole quality are presented and adequately discussed with the primary intent of assessing the drilling behavior of the composite laminates.

Thermal Analysis and Estimation of Tumor Properties in Breast Tissue

Abstract: Diagnosis is one of the important steps while treating a cancer patient. It has been a challenging task to make the diagnostic procedure simple, fast, and less painful. The current work is an effort toward that direction. A human breast tissue is modeled numerically. Thermal analysis is performed on a two-dimensional semi-circular tissue geometry. The Pennes’ bioheat equation is solved using finite volume method for the cases without tumor and with tumor. The solver is validated using COMSOL Multiphysics. Taking temperature profile of the skin surface as the basis, an inverse analysis is performed using genetic algorithm to estimate thermophysical properties, location, and size of the tumor, simultaneously. Optimization of the skin surface temperature profile using genetic algorithm yields a maximum deviation of the blood perfusion rate by 6.67% of its actual value.

Analytical Study for Enhancing Gear Performance Using Al 2 O 3 Paint Coating

Abstract: Nowadays one-time investment is considered better than frequent expenditures of a particular product. To deliver such kind of technology or product is the prime objective of most of the companies. Same goes for the automobile industry. Narrowing the scope for the steering and transmission performance and their fatigue life (mostly rack and pinion which are used in the four-wheeler). In this paper a conventional gear material is taken and has been given a thin paint coating and FEA (Finite Element Analysis) is performed and the stress acting on gear was reduced by 14%. The main objective of this paper is to analyze the total stress acting on the system of a pair of gears having wide application.