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.

A Comparative Study of PI and PID-Based SMC for Anti-Synchronisation of Lorenz-Stenflo Chaotic System

Abstract: The aim of this paper is to anti-synchronise the states of two identical Lorenz-Stenflo (LS) chaotic systems. The LS chaotic system explains the behaviour of atmospheric waves with low frequency and short wavelength, and anti-synchronisation is done using sliding mode control (SMC). A small change in the parameters of the system brings substantial changes in the behaviour of the system due to its chaotic properties. So, a robust control technique, i.e. proportional-integral-derivative (PID) based SMC is used for the anti-synchronisation and the stability of switching surface is shown in this paper. A comparative study is done both qualitatively and quantitatively between the Proportional-Integral (PI) and PID switching surfaces based SMC. Achievement of the proposed designs is guaranteed by the simulation results.

Machining of Bio-composites

Abstract: Due to growing environmental concerns, the engineers and researchers have shifted to using renewable resources to replace many non-renewable, conventional materials like metals and synthetic fibres. Natural fibre-reinforced polymer composites (bio-composites) are usually human-made materials that have gained huge attention in various fields of engineering applications. However, the difficulties in the secondary manufacturing of these composites due to the anisotropic and heterogeneous nature create a barrier in the large-scale production of bio-composites products. This chapter deals with various machining operations associated with natural fibre-reinforced composites. The challenges faced during the machining of natural fibre-reinforced composites have been summarised. Different ways of assisting the quality and improvement of the machined surface have been discussed.

Comparative Analysis of Absorber Tubes of Parabolic Trough Solar Collector Using Therminol VP-1 as Heat Transfer Fluid

Abstract: This paper presents computational analysis of four different types of helically grooved copper absorber tubes (semicircular, rectangular, trapezoidal and triangular) having length of 2 m, inner and outer diameter of 19 and 25 mm, respectively. The flow velocities are calculated by fixing the turbulent Reynolds number of 4000. A constant heat flux of 818.5 W/m2 is supplied at the lower surface of the absorber tube that is facing the reflector. The simulation is performed using the finite volume-based tool ANSYS FLUENT 18.0. The standard k-ɛ RNG turbulence model is used for simulation. Thermo-hydraulic performance for these tubes is calculated as 2.42, 2.08, 2.10 and 2.70 for semicircular, rectangular, trapezoidal and triangular grooved absorber tubes. The results show that the thermal performance of the absorber tube with triangular groove is superior to the other types of grooves. The pressure drop for the same tube is also the lowest.

Simulation of Emission from Coal-Fired Power Plant

Abstract: Sustainability of air quality standard is the major concern across India. Industrialization and particularly the coal-based thermal power plant are the predominant source of air pollution. These atmospheric pollutants have severe impact on the environment. Different types of air dispersion modeling are the most active tools for the assessment of the extent of pollutants and hence the air quality in different environmental conditions. In the current research, Industrial Source Complex Short-Term 3 (ISCST3) tool has been used for simulation of nonlinear advection–diffusion governing differential equation with appropriate boundary condition for prediction of ground-level concentrations of pollutant emission from a coal-fired power plant in Angul, India. The industrial data are used as input to ISCST3. The incremental maximum Ground-Level Concentrations (GLC) of pollutants, when added to the baseline concentrations, are found to be within the acceptance level as per national ambient air quality standard guidelines.

d-CARE: Context-Aware Regulation of Backoff Delay in Wireless Personal Area Networks

Abstract: In this paper, we propose an algorithm for Context-Aware REgulation of backoff delay (d-CARE) in delay-sensitive networks that follow IEEE 802.15.4 standard. The slotted Carrier Sense Multiple Access - Collision Avoidance (CSMA-CA) algorithm prescribed in the standard, to resolve the contention over channel access, does not select the initial Backoff Exponent (BE) value judiciously. In other words, it cannot differentiate between delay-sensitive and delay-tolerant applications. Thus, context-less selection of BE may lead towards a high delay for delay-sensitive applications, for example – real time health monitoring of patients. The proposed d-CARE algorithm uses a Fuzzy Inference System (FIS) to address this problem. As a case study, contexts or attributes that are relevant to healthcare applications are considered as the inputs to the FIS, which generates a BE value as the corresponding output. This judiciously selected BE value produces 12% less delay than the traditional approach.