Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
Browse
10 results
Search Results
Item DQ modeling of induction motor for virtual flux measurement(2010) Sushma, P.; Rajalakshmi Samaga, R.; Vittal, K.P.Three phase induction motors are continuing to remain as work horses in industrial applications. The accurate behavioral modeling of induction motor helps in designing controller for the machine and also useful in detection of faults in machines. Almost all faults in the induction motor affect the flux in the air gap. These fluxes can be measured virtually using dq model of induction motor by feeding voltage and current values extracted in real time and stored. In this paper, DQ model is developed in stator reference frame using MATLAB-SIMULINK platform and a data acquisition system supported with LabVIEW is used to obtain motor terminal voltage and current signals which are useful in estimation of flux in an actual machine. ©2010 IEEE.Item Air gap mixed eccentricity severity detection in an induction motor(2011) Rajalakshmi Samaga, R.; Vittal, K.P.Non invasive fault detection unit for an induction motor has become an integral part of industrial drives. As the current is the primary quantity to get affected by the non uniform air gap flux, Motor Current Signature Analysis is preferred as compared to vibration analysis for mixed eccentricity fault detection in an induction motor. In this paper, Power Spectral Density analysis is performed on the stator current data samples obtained from modeling and simulation of the induction motor. An Eccentricity Severity Factor is defined and is shown that this factor increases with increase of air gap eccentricity in the machine. Hence it can be used as a measure to assess the degree of eccentricity in the machine. © 2011 IEEE.Item Hydrological modeling of stream flow over netravathi river basin(Springer Science and Business Media Deutschland GmbH, 2021) Ashish, S.; Kundapura, S.; Kaliveeran, V.Riverine resources which are the basis of life are being transformed through urbanization. This has to be analyzed effectively in order to rejuvenate riverine ecosystems. The effects of land-use dynamics are a factor to be analyzed, and using hydrological modeling which is adopted in this study aids for the same. Soil and Water Assessment Tool (SWAT) is used as an effective tool in modeling the river basin due to its ability to quantify the alternate input data provided to the model. 14-year daily data was simulated in the model provided; the warm-up period for the model is 2 years. Coefficient of determination value of 0.74 and Nash–Sutcliffe efficiency (NSE) to be 0.71 were obtained from the analysis which indicate that the simulated values fall within a good range. The parameters which influence most are found to be curve number, available water capacity in the soil, groundwater delay, Manning’s n and plant uptake compensation. The fitted range was obtained, and this was used to increase the accuracy in SWAT Calibration and Uncertainty Procedures (SWAT-CUP). Sequential Uncertainty Fitting ver.2 (SUFI2) was found to be effective because of its uncertainty consideration criteria, and it accounts for all uncertainties that may occur in the mode. Hydrological modeling of a river basin can help us to assess the impact of alternative input data on the stream flow. © Springer Nature Singapore Pte Ltd 2021.Item A Review on Application of Soft Computing Techniques in Geotechnical Engineering(Springer Science and Business Media Deutschland GmbH, 2024) Thotakura, T.V.; Sireesha, M.; Sunil, B.M.; Alisha, S.S.Numerous test results, mathematical relationships, and in-the-moment analysis and design are all components of geotechnical issues. Additionally, due to smart infrastructure and materials, the research trend in engineering nowadays is shifting toward intelligent tools and their ability to tackle engineering problems. Artificial neural networks (ANN), support vector machines (SVM), genetic algorithms (GA), and particle swarm optimization algorithms (PSO), among other soft computing techniques, have made significant progress in recent years in solving geotechnical issues. Based on a review of more than 800 published research, this study discusses the applicability of soft computing techniques in the current environment. Traditional methods, such as regression analysis and trial-and-error techniques, take time and could be more effective. Additionally, most geotechnical designs require considerable experimental data and may require laborious work. A novel methodology for soft computing approaches has emerged to solve the problems mentioned above. This paper presents soil problems and geotechnical challenges while examining recent developments and the potential applications of soft computing. © 2024, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Review of non-reactive and reactive wetting of liquids on surfaces(2007) Kumar, G.; Prabhu, K.N.Wettability is a tendency for a liquid to spread on a solid substrate and is generally measured in terms of the angle (contact angle) between the tangent drawn at the triple point between the three phases (solid, liquid and vapour) and the substrate surface. A liquid spreading on a substrate with no reaction/absorption of the liquid by substrate material is known as non-reactive or inert wetting whereas the wetting process influenced by reaction between the spreading liquid and substrate material is known as reactive wetting. Young's equation gives the equilibrium contact angle in terms of interfacial tensions existing at the three-phase interface. The derivation of Young's equation is made under the assumptions of spreading of non-reactive liquid on an ideal (physically and chemically inert, smooth, homogeneous and rigid) solid, a condition that is rarely met in practical situations. Nevertheless Young's equation is the most fundamental starting point for understanding of the complex field of wetting. Reliable and reproducible measurements of contact angle from the experiments are important in order to analyze the wetting behaviour. Various methods have been developed over the years to evaluate wettability of a solid by a liquid. Among these, sessile drop and wetting balance techniques are versatile, popular and provide reliable data. Wetting is affected by large number of factors including liquid properties, substrate properties and system conditions. The effect of these factors on wettability is discussed. Thermodynamic treatment of wetting in inert systems is simple and based on free energy minimization where as that in reactive systems is quite complex. Surface energetics has to be considered while determining the driving force for spreading. Similar is the case of spreading kinetics. Inert systems follow definite flow pattern and in most cases a single function is sufficient to describe the whole kinetics. Theoretical models successfully describe the spreading in inert systems. However, it is difficult to determine the exact mechanism that controls the kinetics since reactive wetting is affected by a number of factors like interfacial reactions, diffusion of constituents, dissolution of the substrate, etc. The quantification of the effect of these interrelated factors on wettability would be useful to build a predictive model of wetting kinetics for reactive systems. © 2007 Elsevier B.V. All rights reserved.Item Modeling of photovoltaic system for uniform and non-uniform irradiance: A critical review(Elsevier Ltd, 2015) Jena, D.; Ramana, V.V.A critical review on various modeling approaches of photovoltaic array both under uniform and non-uniform irradiance is presented in this paper. The main approaches that have been deliberated are based on the variation of analytical methods, classical optimization techniques and soft computing techniques. The review has been taken from papers published up to 2015. In this paper a detailed description and classifications of modeling techniques for both uniform and non-uniform irradiance conditions are presented. Modeling of PV systems under uniform irradiance is classified into non-iterative methods, iterative methods, artificial intelligence based methods and dynamic models. Under non-uniform irradiance, they are classified into non-iterative methods, iterative methods and artificial intelligence based methods. It is envisaged that this paper can serve as valuable information for researchers to work on photovoltaic array modeling under partial shaded condition. © 2015 Elsevier Ltd. All rights reserved.Item Understanding the role of modeling and simulation in pyrolysis of biomass and waste plastics: A review(Elsevier Ltd, 2022) Ramesh, R.; Suriapparao, D.V.; Sankar Rao, C.S.; Kumar, T.H.The valorization of resources from biomass and plastic waste using thermochemical platforms is an innovative approach. Pyrolysis is thermochemical technology that is very effective in the production of fuels and chemical intermediates. It's conducted by conventional heating, solar heating, and microwave-controlled heating. Compared to conventional pyrolysis, microwave-assisted pyrolysis is more advantageous. The temperature distribution, mass transfer, and heat transfer rates depend on the operation mode through process parameters. The optimization of the pyrolysis process is crucial for scale-up. Computer-assisted modeling and simulation techniques help to develop suitable configurations and experimental methods for better efficiencies. Modeling allows the identification of optimum operating parameters and understanding of transportation mechanisms involved in pyrolysis. Modeling, simulation, and optimization are ideally suited to understanding and analyzing the complex stages of pyrolysis. This review provides insight into existing heat, mass, and momentum transfer models for pyrolysis. The effects of transport properties on pyrolysis are dealt with. © 2022 Elsevier LtdItem Innovative structural engineering of sustainable and environment-friendly Cu2ZnSnS4 solar cell for over 20% conversion efficiency(John Wiley and Sons Ltd, 2022) Prabhu, S.; Pandey, S.K.; Chakrabarti, S.Kesterite Cu2ZnSnS4(CZTS) thin-film technology has been comprehensively investigated over the last decade as a promising candidate in the field of photovoltaic technologies. However, despite numerous strategies to improve the performance, the efficiencies remain stagnant at around 11%. Poorly optimized absorber/buffer interface, non-absorption of higher wavelength photons, and non-ohmic back contact are the primary reasons for the poor performance of the CZTS solar cell. The authors of this paper propose a cadmium-free buffer layer, multiple quantum wells (MQWs) structure, and a back surface field (BSF) layer to overcome these issues, respectively. In this study, the buffer layer, zinc oxysulfide (Zn[O1−xSx]) is considered as an alternative to toxic Cadmium Sulfide (CdS) for better band alignment with the CZTS absorber layer. Cu2ZnSn(SxSe1−x)4 (CZTSSe) is used as a quantum well material in MQWs to increase photon absorption in CZTS solar cells. Tin selenide (SnSe) is used as the BSF layer to reduce the effect of non-ohmic back contact and to improve the open-circuit voltage (Voc) of MQW incorporated CZTS solar cells. Detailed analysis and optimization of the modified structure with higher performance are presented. The simulation results obtained provide imperative guidelines for the fabrication of high-efficiency CZTS solar cells using non-toxic and earth-abundant materials. © 2022 John Wiley & Sons Ltd.Item Comparison of the Experimental and Modelling Results of Mechanical Characteristics of LM6 and LM9 Alloy for Tractor Application(Springer, 2023) Shetteppanavar, C.C.; Shinde, R.B.; Hanumanthappa, H.; Mohanraj, G.T.; Shanmugam, B.K.S.; Srivatsav, S.K.Y.; Kavitha Kumar, A.R.B.K.In India, the development of composite and alloys material has provided the required characteristics material. In this study, an attempt has been made to compare the performance of LM6 and LM9 alloy for an automobile application. These alloys are studied based on the tensile strength and fatigue test required for the pullet used in tractor application. The tensile test results showed that the LM9 alloy specimen has higher strength than the LM6 alloy specimen. Furthermore, results showed that the fatigue strength of the LM9 alloy specimen was found to be higher than the LM6 alloy specimen. Further, the tensile and fatigue materials behaviour of LM6 and LM9 specimens were compared through ANSYS modelling. From the experimental and modelling results, it was clear that the modelling results are in close agreement with the tensile and fatigue experimental results. The mechanical characteristics such as tensile and fatigue strength of the LM9 specimen were found to be much better than the LM6 specimen. The microstructural analysis also showed higher silicon particles providing higher strength for LM9 specimens than LM6 specimens. The pulley material made out of LM9 alloy will avoid the shear failure occurrence of the pulley. © 2022, The Institution of Engineers (India).Item A Detailed Study of SOT-MRAM as an Alternative to DRAM Primary Memory in Multi-Core Environment(Institute of Electrical and Electronics Engineers Inc., 2024) Kallinatha, H.D.; Rai, S.; Talawar, B.As the current primary memory technology is reaching its limits, it is essential to explore alternative memory technologies to accommodate modern applications and use cases. However, using new memory technology poses the challenge of deriving accurately estimated parameters for integrating new memory technology and doing reliable simulations. This study proposes a new approach incorporating Spin-Orbit-Torque-Magnetic-RAM (SOT-MRAM) into hybrid and full main memory architectures within a multi-core system, encompassing various memory configurations and capacities. The study addresses the challenge of evaluating SOT-MRAM-based memory systems when specific SOT-MRAM memory parameters are not publicly available. The research methodology includes micro-architectural (circuit-level) design space exploration and comprehensive full system simulations, which evaluate benchmark programs representing diverse application domains. The evaluation includes three memory structures with varying memory organizations and capacities. The results show that SOT-MRAM is a robust replacement for DRAM or hybrid memory, offering compelling advantages such as a remarkable 74.05% reduction in power consumption, a noteworthy 40.10% increase in bandwidth utilization, and a significant 72.85% reduction in Energy-Delay Product (EDP). The maximum latency penalties are also minimal, with a 3.71% increase for hybrid structures and a mere 0.07% for standalone SOT-MRAM memory structures. © 2013 IEEE.