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.

Automatic generation control of multi-area system using non-integer order I λ D μ controller

Abstract: In this paper a maiden attempt has been made to examine and investigates the effect of bacterial foraging (BF) optimized fractional order integral and derivative (FOID or IλDμ) controller in automatic generation control (AGC) of a multi-area thermal system considering single stage of reheat turbine and appropriate generation rate constraint (GRC) The performances of several classical integer-order (IO) controllers such as I, PI and PID controllers is evaluated and compared with IλDμ controller to assess the best controller Investigation reveals that IλDμ controller provides better performance than the IO controllers in terms of settling time, reduced oscillations and peak overshoots This paper employs bacterial foraging algorithm for optimization of gains and other parameters such as order of integrator (λ) and differentiator (μ) in case of IλDμ controller Further, sensitivity analysis is carried out for the first time in the system considered to investigate the robustness of the optimum gains, λ and μ of IλDμ controllers obtained at nominal condition

Entropy generation in MHD nanofluid flow induced by a slendering stretching sheet with activation energy, viscous dissipation and Joule heating impacts

Abstract: This research article looks at entropy generation and activation energy analysis on hydromagnetic and thermally radiated nanofluid flow generated by a nonlinearly stretching sheet of variable thickness considering heat generation, mixed convection, velocity slip, viscous dissipation, thermal slip, binary chemical reaction and Ohmic dissipation aspects. Governing model equations of continuity, momentum, energy and concentration are converted into ODEs by employing appropriate similarity transformations. The resulting coupled highly nonlinear equations have been solved numerically with the help of the Runge–Kutta–Fehlberg method-based shooting technique. Results obtained for a particular case of the current fluid flow problem are in good agreement with the existing results. The graphical outcomes are discussed for velocity, temperature, entropy generation and concentration regarding various controlling parameters. The impacts of different controlling parameters on the local skin-friction coefficient, local Nusselt and Sherwood numbers are also analyzed and the numerical results are presented in tabular form. The obtained results reveal a reduction in entropy generation for growing values of magnetic and temperature ratio parameters near the solid surface, while a reverse effect is noticed for power-law index and Brinkmann number.

Parametric Study of Photochemical Machining of Aluminium Using Taguchi Approach

Abstract: This paper described a parametric optimization for photochemical machining process on aluminium work material. The study analysed the parametric effects of etching concentration, etching temperature, and etching time on the performance measures like, material removal rate, surface roughness and edge deviation of predefined boundary of area. Based on Taguchi L9 orthogonal array, the photochemical machining of aluminium was carried out using ferric chloride solution as etchant. Analysis of Variance showed the effects of different process parameters on performance measures. Overall evaluation criteria were formulated by desired weight percentage to material removal rate, surface roughness and edge deviation for achieving multi-objective condition. The optimum condition was found to be 400 g/L of etching concentration, 40 °C of etching temperature and 6 min of etching time. ANOVA of OEC showed that the etching temperature was the most significant factor for machining of aluminium workpiece.

Sensing of ammonia gas by undoped and aluminum-doped tin oxide nanoparticles by Raman spectroscopy

Abstract: The study of gas sensing properties of $$\hbox {SnO}_{2}$$ has been widely carried out mainly using electrical methods where a change in resistance or / and conductance of $$\hbox {SnO}_{2}$$ is measured when it is exposed to the sample. In this work, a spectroscopic approach was employed using Raman intensity as a tool to study the sensing of ammonia by undoped and aluminum-doped $$\hbox {SnO}_{2}$$ nanoparticles. The study showed a variation of intensity of the classical Raman modes of $$\hbox {SnO}_{2}$$ , when $$\hbox {SnO}_{2}$$ was exposed to ammonia. The response to ammonia by nanoparticles of different sizes and doping concentrations was calculated. This study also revealed the optimum crystallite size and doping concentration suitable for sensing ammonia. However, the most important conclusion that could be drawn from this study was that the response of $$\hbox {SnO}_{2}$$ to ammonia could be detected at room temperature through Raman spectroscopy unlike in the case of electrical studies, where a high temperature is required for sensing.

Simulation of Natural Gas Combustor Using CFD

Abstract: The combustors are the direct-fired heaters or burners where the fuel burns in stoichiometric composition and evolves an enormous amount of heat for process heating. The natural gas combustor utilizes natural gas as fuel for the combustion process. Several designs of natural gas combustors are available for the above-said process; based on the application, the design of the combustor is determined. The current research is motivated towards the CFD simulation of natural gas combustor using Species Transport model along with different Turbulence models (Standard k − ℇ, Realizable k − ℇ, RNG k − ℇ, Standard k − ω and SST k − ω) and Radiation models (Discrete Ordinate (DO), P1 and Rosseland) in two different simulation tools (Ansys Fluent and Star CCM+). The flow, thermal and combustion analysis of natural gas combustor is performed with the above-mentioned combustion, radiation and turbulence models in Ansys Fluent. The results obtained from the simulation using Ansys Fluent are compared with the available experimental results of Sayre et al. (Scaling Characteristics of Aerodynamics and Low-NOx Properties of Industrial Natural Gas Burners, The SCALING 400 Study, Part IV: The 300 kW BERL Test Results. International Flame Research Foundation, The Netherlands, 1994, [1]) to validate the adopted methodology. The best-predicted turbulence and radiation model, along with the Species Transport model, is used in Star CCM+. The simulated results in both the software are compared with the experimental results and are in close agreement.