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Shanmugasundram R.,Sri Ramakrishna Engineering College | Yadaiah N.,JNTUH College of Engineering
IEEE/ASME Transactions on Mechatronics | Year: 2014

This paper presents design and digital implementation of a fuzzy controller for achieving improved performance of Brushless dc (BLDC) servomotor drive. The performance of fuzzy and PID controller-based BLDC servomotor drives is investigated under different operating conditions such as change in reference speed, parameter variations, load disturbance, etc. BLDC servomotors are used in aerospace, instrumentation systems, space vehicles, electric vehicles, robotics, and industrial control applications. In such applications, conventional controllers like P, PI, and PID are being used with the BLDC servomotor drive control systems to achieve satisfactory transient and steady-state responses. However, the major problem associated with the conventional PID controller is that the tuned gain parameters obtained for such BLDC servomotor drive control systems do not yield better transient and steady-state responses under different operating conditions such as parameter variations, load disturbances, etc. In this paper, design and implementation of fuzzy controller is presented and its performance is compared with PID controller to show its capability to track the error and usefulness of fuzzy controller in control applications.©1996-2012 IEEE.


Prasanna P.,JNTUH College of Engineering
International Journal of Advanced Manufacturing Technology | Year: 2010

Friction stir welding is a relatively new joining process, which involves the joining of metals without fusion or filler materials. The amount of the heat conducted into the workpiece dictates a successful process which is defined by the quality, shape, and microstructure of the processed zone, as well as the residual stress and the distortion of the workpiece. The amount of the heat gone to the tool dictates the life of the tool and the capability of the tool to produce a good-processed zone. Hence, understanding the heat transfer aspect of the friction stir welding is extremely important, not only for the science but also for improving the process. Many research works were carried out to simulate the friction stir welding using various software to determine the temperature distribution for a given set of conditions in weldments. Very few attempted to determine the maximum temperature by varying the input parameters using ANSYS. The objective of this research is to develop a finite element simulation with improved capability to predict temperature evolution in stainless steel. The simulation model is tested with existing experimental results obtained by Zau et al. on 304 L stainless steel. The results of the simulation are in good agreement with that of experimental results. The peak temperature obtained was 1,056.853°C, which was much less than the melting point of 304 L steel (1,450°C). Error analysis is done between theoretical values for 304 L steel obtained from ANSYS and experimental values obtained by Zhu. Mean relative error is calculated between theoretical values for 304 L steel and experimental values. © 2010 Springer-Verlag London Limited.


Naveen Kumar G.,VNRVJIET | Surya Kalavathi M.,JNTUH College of Engineering
International Journal of Electrical Power and Energy Systems | Year: 2014

Voltage stability categorized under various classifications of power system stability is considered one of the important subjects in power systems stability studies. A power system, experiencing disturbances, is at risks of voltage instability. Main reason for the cause of voltage instability is the sag in reactive power at various locations due to circuit contingencies classified under large disturbance voltage stability. The aim of this paper is to identify the optimal location of Unified Power Flow Controller in an interconnected power system under N-1 contingency. As the size and the cost of the FACTS devices are high, an optimal location and size has to be identified before they are actually installed. We are trying to improve the voltage profile and Maximum Loading Parameter using Unified Power Flow Controller while determining their optimal location based upon Cat Swarm Optimization. © 2013 Elsevier Ltd. All rights reserved.


Gunda J.B.,Advanced Systems Laboratory | Gupta R.K.,Advanced Systems Laboratory | Ranga Janardhan G.,JNTUH College of Engineering | Venkateswara Rao G.,Sreenidhi Institute of Science and Technology
Composite Structures | Year: 2011

Large amplitude vibration analysis of laminated composite beam with axially immovable ends is investigated with symmetric and asymmetric layup orientations by using the Rayleigh-Ritz (R-R) method. The displacement fields used in the analytical formulation are coupled by using the homogeneous governing static axial equilibrium equation of the beam. Geometric nonlinearity of von-Karman type is considered which accounts for the membrane stretching action of the beam. The simple closed-form solutions are presented for the nonlinear harmonic radian frequency as function of central amplitude of the beam using the R-R method. The nonlinear harmonic radian frequency results obtained from the closed-form solutions of the R-R method in general show good agreement with the results obtained from simple iterative finite element formulation. Furthermore, the closed-form expressions are corrected for the harmonic motion assumption from the available literature results on the existence of quadratic and cubic nonlinearity. It is interesting to note that the composite beams can result in asymmetric frequency vs. amplitude curves depending upon the nature of direction of displacement in contrast to isotropic beams which exhibit cubic nonlinearity only and leads to symmetric frequency vs. amplitude curves with respect to sign of the amplitude. © 2010 Elsevier Ltd.


Hussein A.M.,Universiti Malaysia Pahang | Hussein A.M.,Al Haweeja Institute | Sharma K.V.,JNTUH College of Engineering | Bakar R.A.,Universiti Malaysia Pahang | Kadirgama K.,Universiti Malaysia Pahang
Renewable and Sustainable Energy Reviews | Year: 2014

The low thermal properties of liquids have led to investigations into additives of small size (less than 100 nm solid particles) to enhance their heat transfer properties and hydrodynamic flow. To summarise the experimental and numerical studies, this paper reviews these computational simulations and finds that most of them are in agreement with the results of experimental work. Many of the studies report enhancements in the heat transfer coefficient with an increase in the concentration of solid particles. Certain studies with a smaller particle size indicated an increase in the heat transfer enhancement when compared to values obtained with a larger size. Additionally, the effect of the shape of the flow area on the heat transfer enhancement has been explored by a number of studies. All of the studies showed a nominal increase in pressure drop. The significant applications in the engineering field explain why so many investigators have studied heat transfer with augmentation by a nanofluid in the heat exchanger. This article presents a review of the heat transfer applications of nanofluids to develop directions for future work. The high volume fraction of various nanofluids will be useful in car radiators to enhance the heat transfer numerically and experimentally. Correlation equations can expose relationships between the Nusselt number, the Reynolds number, the concentration and the diameter of the nanoparticles. On the other hand, more work is needed to compare the shapes (e.g., circular, elliptical and flat tube) that might enhance the heat transfer with a minimal pressure drop. © 2013 Elsevier Ltd. All rights reserved.


Rama Krishna L.,International Advanced Research Center for Powder Metallurgy And New Materials | Poshal G.,JNTUH College of Engineering | Sundararajan G.,International Advanced Research Center for Powder Metallurgy And New Materials
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science | Year: 2010

In the present work, micro arc oxidation (MAO) coatings were synthesized on magnesium substrate employing 11 different electrolyte compositions containing systematically varied concentrations of sodium silicate (Na2SiO 3), potassium hydroxide (KOH), and sodium aluminate (NaAlO 2). The resultant coatings were subjected to coating thickness measurement, energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), image analysis, and three-dimensional (3-D) optical profilometry. The corrosion performance of the coatings was evaluated by conducting potentiodynamic polarization tests in 3.5 wt pct NaCl solution. The inter-relationships between the electrolyte chemistry and the resulting chemistry and porosity of the coating, on one hand, and with the aqueous corrosion behavior of the coating, on the other, were studied. The changes in pore morphology and pore distribution in the coatings were found to be significantly influenced by the electrolyte composition. The coatings can have either through-thickness pores or pores in the near surface region alone depending on the electrolyte composition. The deleterious role of KOH especially when its concentration is >20 pct of total electrolyte constituents promoting the formation of large and deep pores in the coating was demonstrated. A reasonable correlation indicating the increasing pore volume implying the increased corrosion was noticed. © 2010 The Minerals, Metals & Materials Society and ASM International.


Jayasankaraprasad C.,Krishna University | Kathyayani G.,JNTUH College of Engineering
International Review of Retail, Distribution and Consumer Research | Year: 2014

The main purpose of this study is to explore cross-format shopping motives among grocery consumers and to categorise cross-format shopping typologies based on identified motives. The paper also aims to identify common consumer subgroups amongst the customer base of different retail formats and differences among shopper segments in relation to format choice and repeat patronage (loyalty). In this method, exploratory qualitative (semi-structured personal interviews) and quantitative research (mall intercept survey) approaches were used. Primary data were collected from 1040 grocery consumers by self-administering a structured questionnaire. Multivariate techniques including exploratory factor analysis, k-means cluster analysis, multiple discriminant analysis, multivariate analysis of variance, and χ2 tests were applied to test the formulated propositions. This paper identifies nine cross-format shopping motivations: value for money, value for time, price-conscious, local shopping, shopping enjoyment, social shopping, variety seeking, entertainment, and brand-conscious motives. Based on these central dimensions, this paper finds five cross-format shopper segments: economic shopper, convenience shopper, price-promotional shopper, hedonic shopper, and social shopper. The study also indicates that there are significant differences amongst shopper typologies in relation to retail format choice and repatronage. This study provides specific knowledge of the cross-shopping motives to the grocery retailers that consumers consider important when making format choices. The study also helps retailers develop various retailing strategies to increase store format loyalty. Despite the importance of understanding grocery consumers' cross-shopping, little research has been conducted to investigate the growing incidence of cross-format shopping. Given the absence of published academic literature in relation to cross-format shopping behaviour in the context of emerging retail markets, the empirical evidence may serve as a departure point for future studies in this area of concern. The research is relevant to grocery retailers in terms of format development. © 2013 Taylor & Francis.


Manasa N.L.,JNTUH College of Engineering
ACM International Conference Proceeding Series | Year: 2016

The spread of terrorist assaults over the globe in the most recent decade has underscored the significance of detecting concealed explosives and called for new propelled innovations to ensure the protection of general population. Smelling reminiscent and hidden explosive odours like canines is likely largely a beneficial tool for security personnel. However, various other methods can also be adopted to the basic problem of explosive detection: Trace, bulk and vapour detection. Despite the fact that all methods may satisfy distinctive parts of a general security chain, the underlying scientific aspects differ steadily. This review focuses on the identification of concealed explosives and their precursors. Miniaturized devices with great sensing capabilities are hoped to be realized by the nanosensor domain. Nanosensor technologies with the tremendous potential to form viable technological platforms for trace explosive detection are (a) nanowire/ nanotube (b) nanomechanical devices and (c) Electronic noses. This paper primarily focuses on the different scientific aspects of these explosives detection technologies by elaborating primarily on the Electronic nose technology. © 2016 ACM.


Sundar L.S.,JNTUH College of Engineering | Sharma K.V.,Universiti Malaysia Pahang | Sharma K.V.,JNTUH College of Engineering
International Journal of Heat and Mass Transfer | Year: 2010

The turbulent convective heat transfer and friction factor behavior of Al2O3 nanofluid in a circular tube with different aspect ratios of longitudinal strip inserts are studied experimentally. Experiments are conducted with water and nanofluid in the range of 3000


Sundar L.S.,JNTUH College of Engineering | Sharma K.V.,Universiti Malaysia Pahang | Sharma K.V.,JNTUH College of Engineering
International Journal of Heat and Mass Transfer | Year: 2010

The thermophysical properties like thermal conductivity and viscosity of Al2O3 nanofluid is determined through experiments at different volume concentrations and temperatures and validated. Convective heat transfer coefficient and friction factor data at various volume concentrations for flow in a plain tube and with twisted tape insert is determined experimentally for Al2O3 nanofluid. Experiments are conducted in the Reynolds number range of 10,000-22,000 with tapes of different twist ratios in the range of 0 < H/D < 83. The heat transfer coefficient and friction factor of 0.5% volume concentration of Al2O3 nanofluid with twist ratio of five is 33.51% and 1.096 times respectively higher compared to flow of water in a tube. A generalized regression equation is developed for the estimation of Nusselt number and friction factor valid for both water and nanofluid in plain tube and with inserts under turbulent flow conditions. © 2009 Elsevier Ltd. All rights reserved.

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