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Vishākhapatnam, India

Devaki Rani S.,JNTUH College of Engineering | Murthy G.S.,Raghu Engineering College
Journal of Materials Engineering and Performance | Year: 2013

Lead-free solders are fast emerging as better alternatives to Sn-Pb solders. The reliability of a soldered joint to withstand imposed stresses in an assembly is decided by its mechanical properties. The present work is about the investigation of tensile and shear properties of four binary eutectic alloys Sn-3.5Ag, Sn-58Bi, Sn-0.7Cu, Sn-9Zn and a ternary alloy Sn-57Bi-1.3Zn in comparison with conventional Sn-38Pb alloy. It is observed that the lead-free solders have better mechanical properties than the latter. SEM studies of tensile and shear fracture show ductile dimples circular in tension and parabolic in shear modes supporting the mechanical behavior of the alloys investigated. Eutectic alloys Sn-Ag, Sn-Zn, and Sn-Cu form potential substitutes for Sn-Pb for electronic interconnects exposed to high temperatures, while Sn-Bi and Sn-Bi-Zn are attractive alternatives in addressing the need of lower processing temperatures in printed circuit boards and other applications. © 2013 ASM International. Source


Pullabhatla S.,KKR | Chintakayala P.,Raghu Engineering College
Advances in Intelligent and Soft Computing | Year: 2012

In the present paper power system transient disturbances using Stockwell and Hartley Stockwell transform have been investigated. It is well known that Stockwell transform (ST) is utilized for the real time prediction of the disturbance as it is able to accurately determine the sudden burst in the signal. However, in some cases the frequency resolution of ST is low. Consequently Hartley Stockwell transform (HST) has been proposed which is good in frequency resolution. A comparison has been made with the proposed HST with ST technique. The proposed HST technique has been tested on various transient disturbances to show its efficacy. © 2012 Springer-Verlag GmbH Berlin Heidelberg. Source


Gupta P.K.,Raghu Engineering College | Pagalthivarthi K.V.,GIW Industries Inc.
World Academy of Science, Engineering and Technology | Year: 2011

The present work compares the performance of three turbulence modeling approach (based on the two-equation k -ε model) in predicting erosive wear in multi-size dense slurry flow through rotating channel. All three turbulence models include rotation modification to the production term in the turbulent kineticenergy equation. The two-phase flow field obtained numerically using Galerkin finite element methodology relates the local flow velocity and concentration to the wear rate via a suitable wear model. The wear models for both sliding wear and impact wear mechanisms account for the particle size dependence. Results of predicted wear rates using the three turbulence models are compared for a large number of cases spanning such operating parameters as rotation rate, solids concentration, flow rate, particle size distribution and so forth. The root-mean-square error between FE-generated data and the correlation between maximum wear rate and the operating parameters is found less than 2.5% for all the three models. Source


Poornaprakash B.,Yeungnam University | Poojitha P.T.,Siddartha Educational Academy Group of Institutions | Chalapathi U.,Yeungnam University | Subramanyam K.,Raghu Engineering College | Park S.-H.,Yeungnam University
Physica E: Low-Dimensional Systems and Nanostructures | Year: 2016

The compositional, structural, optical and magnetic properties of ZnS, Zn0.98Co0.02S, Zn0.98Sm0.02S and Zn0.96Co0.02Sm0.02S nanoparticles synthesized by a hydrothermal method are presented and discussed. X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED) studies revealed that all the samples exhibited cubic structure without any impurity phases. X-ray photoelectron spectroscopy (XPS) results revealed that the Co and Sm ions existed in +2 and +3 states in these samples. The photoluminescence (PL) spectra of all the samples exhibited a broad emission in the visible region. The room temperature magnetization versus applied magnetic field (M-H) curves demonstrated that the Sm+Co doped nanoparticles exhibited enhanced ferromagnetic behavior compare to Co and Sm individually doped ZnS nanoparticles, which is probably due to the exchange interaction between conductive electrons with local spin polarized electrons on the Co2+ or Sm3+ ions. This study intensifies the understanding of the novel performances of co-doped ZnS nanoparticles and also provides possibilities to fabricate future spintronic devices. © 2016 Elsevier B.V. Source


Siva Rao I.S.,Raghu Engineering College | Srinivasa Rao T.,Gandhi Institute of Technology and Management
International Journal of Applied Engineering Research | Year: 2016

The heart diseases are the most widespread induce for human dying. Every year, 7.4 million deaths are attributed to heart diseases (cardiac arrhythmia) including 52% of deaths due to strokes and 47% deaths due to coronary heart diseases. Hence identification of different heart diseases in the primary stages becomes important for the protection of cardiac related deaths. The existing conventional ECG analysis methods like, RR interval, Wavelet transform with classification techniques, such as, Support Vector machine K-Nearest Neighbor and Levenberg Marquardt Neural Network are used for detection of cardiac arrhythmia Using these methods large number of features are extracted but it will not identify exactly the problem. Studies conducted in this paper work to carry out these individual optimization techniques which did not give the desired identification accuracy. It is also proposed to modify these techniques as the system is advised based on universal filtering, pulse identification, clustering, categorization of signal with small delay can be done to identify the life threatening arrhythmia. Double differentiation with multi- discrete wavelet transforms which protect time changing QRS complex as well as noise. The proposed multi wavelet transform modeling provides temporal and spectral information coincidental, and extends reach stretch ability with a potential of multi wavelet functions of dissimilar signal properties. The present development implicated with the origin of QRS complexes of ECG signals using a new finite set of algorithms constructed based on ECG Q R S T waveform shaping it is possible to find out whether the person is in normal or abnormal and identification of different diseases with possibility effect, existing standard Pan-Tompkins method and multi wavelet transform techniques evaluated using MATLAB. Then removing discrepant wavelet transform coefficients and denoising is done in ECG signal. In addition to that QRS complex will be detected and each complex will be used to find the peaks of t e individual waves like, P and T, and their derivatives. At the end we are going to generate different disease inputs for the ECG signal by providing the heart beat rate, generate p, r waves. The values can be altered by observing the heart diseases and based on that real time inputs we can build the neural network and check the efficiency of the system. Kurtosis, neural network classification to achieve significant identification accuracy. This paper mainly aims at improving the identification and performance of the system to detect heart disease based on neural network classification. © 2016, Research India Publications. Source

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