Machilipatnam, India
Machilipatnam, India

Acharya Nagarjuna University is a university in the region of Namburu, Guntur, Andhra Pradesh, India. It is one of the major universities in the country covering many colleges and institutes of districts in the region. It is located in Nagarjuna Nagar, Namburu on the Northern part of Guntur City, a major centre for learning in the state of Andhra Pradesh.The university is an outgrowth of a post-graduate centre of Andhra University, which was established in 1967 at Nallapadu area of Guntur and then relocated to Nambur/Kaza area on the east of the city. The centre gained affiliating university status in 1976 and opened with ten post-graduate courses. The university is named after Acharya Nagarjuna, the pro-founder of the Madhyamaka path of Mahayana Buddhism. Wikipedia.

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Santhi Kumar R.,Aditya Institute of Technology | Pradeep Kumar T.V.,Acharya Nagarjuna University
International Journal of Theoretical Physics | Year: 2013

A dark energy model with EoS parameter is investigated in f(R,T) gravity in Bianchi type-III space-time in the presence of perfect fluid source. To obtain a determinate solution special law of variation for Hubble's parameter proposed by Berman (Nuovo Cimento B 74:183, 1983) is used. We have also assumed that the scalar expansion is proportional to shear and the EoS parameter is proportional to skewness parameter. It is observed that the EoS parameter, skewness parameters in the model turn out to be functions of cosmic time. Some physical and kinematical properties of the model are also discussed. © 2012 Springer Science+Business Media, LLC.

Mahmood A.M.,Acharya Nagarjuna University
Engineering with Computers | Year: 2012

Classification is an important data mining task that discovers hidden knowledge from the labeled datasets. Most approaches to pruning assume that all dataset are equally uniform and equally important, so they apply equal pruning to all the datasets. However, in real-world classification problems, all the datasets are not equal and considering equal pruning rate during pruning tends to generate a decision tree with large size and high misclassification rate. We approach the problem by first investigating the properties of each dataset and then deriving data-specific pruning value using expert knowledge which is used to design pruning techniques to prune decision trees close to perfection. An efficient pruning algorithm dubbed EKBP is proposed and is very general as we are free to use any learning algorithm as the base classifier. We have implemented our proposed solution and experimentally verified its effectiveness with forty real world benchmark dataset from UCI machine learning repository. In all these experiments, the proposed approach shows it can dramatically reduce the tree size while enhancing or retaining the level of accuracy. © 2011 Springer-Verlag London Limited.

Ramanjaneyulu K.,Acharya Nagarjuna University | Rajarajeswari K.,Andhra University
IET Image Processing | Year: 2012

In this work, a robust and oblivious image watermarking scheme based on discrete wavelet transform (DWT) for copyright protection is presented. The original unmarked image is not required for watermark extraction. Third-level DWT is applied to the original cover image. Third- and second-level horizontal detail sub-band (LH2 and LH3) coefficients are grouped into different blocks. Grouping of the coefficients is done in such a way that each block should contain one coefficient from LH3 sub-band and four coefficients from LH2 sub-band. In each block, the first minimum and the second minimum are identified and modified according to the watermark bit. After watermark insertion, inverse DWT is applied to the sub-bands with modified coefficients to obtain the watermarked image. For watermark extraction, a threshold-based decoder is designed. Embedding and extraction process are characterised with parameters and genetic algorithm is used for parameter optimisation. Optimisation is to maximise the values of peak signal-to-noise ratio of the watermarked image and normalised cross correlation of the extracted watermark. The performance of the proposed scheme is compared with the existing schemes and significant improvement is observed. Experimental results show that, this algorithm is highly robust for many image attacks on the watermarked image. © 2012 The Institution of Engineering and Technology.

Gnaneswara Reddy M.,Acharya Nagarjuna University
Journal of Engineering Physics and Thermophysics | Year: 2015

The unsteady two-dimensional flow of a non-Newtonian fluid over a stretching surface with the effects of thermal radiation and variable thermal conductivity is investigated. The Casson fluid model is used to characterize the non- Newtonian fluid behavior. First, using a similarity transformation, the governing time-dependent partial differential equations are transformed into coupled nonlinear ordinary differential equations with variable coefficients. Then the transformed equations are solved numerically under appropriate boundary conditions by the shooting method. An exact solution corresponding to the momentum equation for a steady case is found. The obtained numerical results are analyzed as to the effect of the pertinent parameters on the flow and heat transfer characteristics. ©2015 Springer Science+Business Media New York.

Reddy M.G.,Acharya Nagarjuna University
International Journal of Heat and Technology | Year: 2014

In this analysis, the boundary layer flow and heat and mass transfer over a vertical plate due to a nanofluid with the effects of thermal radiation and uniform heat flux have been investigated. The transport equations used in the analysis took into account the effect of Brownian motion and thermophoresis parameters. Similarity transformation is used to convert the governing non-linear boundary-layer equations into coupled higher order non-linear ordinary differential equations. These equations are numerically solved using fourth order Runge-Kutta method along with shooting technique. An analysis has been carried out to elucidate the effects of governing parameters corresponding to various physical conditions. The dimensionless skin friction increases as the Prandtl number, but decreases as the buoyancy ratio parameter and radiation parameter increases. The reduced Nusselt number increases as the Prandtl number and radiation parameter increase. Comparison with published results is presented.

Bala Murali Krishna S.,Acharya Nagarjuna University | Krishna Rao D.,Acharya Nagarjuna University
Journal of Alloys and Compounds | Year: 2011

Five glasses in the quaternary system 5 ZnO-(50 - x) As2O 3-45 Sb2O3: x WO3 with the values of x ranging from 0 to 20 mol% (in steps of 5 mol%) are prepared. The samples are characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy (EDS) and differential thermal analysis (DTA) techniques. The DTA studies have indicated that the glass forming ability decreases with the increasing content of WO3. A number of studies, like, spectroscopic (optical absorption, IR, Raman, ESR spectra) and dielectric studies (dielectric constant ε, loss tan δ, a.c. conductivity σa.c.) over a wide range of frequency and temperature and dielectric break down strength at room temperature, have been carried out and are analysed in the light of different oxidation states and environment of tungsten ions in these glasses. These glasses have potential photonic applications. © 2011 Elsevier B.V. All rights reserved.

Machireddy G.R.,Acharya Nagarjuna University
Ain Shams Engineering Journal | Year: 2013

The numerical solution of transient natural convection flow of radiation effects on MHD heat and mass transfer past a moving vertical cylinder with chemical reaction is presented. The governing boundary layer equations for the above flow problem of first-order homogeneous chemical reaction are setup and non-dimensionalized. An implicit finite difference method is used to solve the unsteady, non-linear, and coupled governing equations. Numerical results are presented for various parameters. The unsteady velocity, temperature, concentration profiles, local and average skin-friction, Nusselt number, and Sherwood number are shown graphically and are discussed for both generative and destructive reaction. © 2013 Ain Shams University. Production and hosting by Elsevier B.V. All rights reserved.

Rajyasree C.,Acharya Nagarjuna University | Rao D.K.,Acharya Nagarjuna University
Journal of Non-Crystalline Solids | Year: 2011

Transparent glasses of the composition 10RO.20Bi2O 3.(70 - x) B2O3.xCuO [R = Ca, Ba] with x = 0, 0.4, 0.8 (wt.%) were prepared via melt-quenching technique and characterized using X-ray powder diffraction. Spectroscopic measurements, viz., optical absorption, EPR, FTIR and photoluminescence (PL) were studied at room temperature. Analysis of the present investigations indicates that the concentration of luminescence centers of bismuth ions (Bi2+ ions in visible region) decreased by the integration of BaO and also by increasing dopent concentration. It is also observed that addition of CuO decreases stability of the glass network in calcium series and strengthens in barium series. © 2010 Elsevier B.V. All rights reserved.

This article concerns with a steady two-dimensional flow of an electrically conducting incompressible dissipating fluid over an inclined semi-infinite surface with heat and mass transfer. The flow is permeated by a uniform transverse magnetic field. A scaling group of transformations is applied to the governing equations. The system remains invariant due to some relations among the parameters of the transformations. After finding three absolute invariants, a third-order ordinary differential equation corresponding to the momentum equation, and two secondorder ordinary differential equations corresponding to energy and diffusion equations are derived. The coupled ordinary differential equations along with the boundary conditions are solved numerically. Comparisons with previously published work are performed and the results are found to be in very good agreement. Many results are obtained and a representative set is displayed graphically to illustrate the influence of the various parameters on the dimensionless velocity, temperature and concentration profiles. It is found that the velocity increases with an increase in the thermal and solutal Grashof numbers. The velocity and concentration of the fluid decreases with an increase in the Schmidt number. The results, thus, obtained are presented graphically and discussed.

An analytical study for the problem of mixed convection with thermal radiation and first-order chemical reaction on magnetohydrodynamics boundary layer flow of viscous, electrically conducting fluid past a vertical permeable surface embedded in a porous medium has been presented. Slip boundary condition is applied at the porous interface. The heat equation includes the terms involving the viscous dissipation, radiative heat flux, Ohmic dissipation, the internal absorption and absorption of radiation, whereas the mass transfer equation includes the effects of chemically reactive species of first order. The dimensionless governing equations for this investigation are formulated and the non-linear coupled differential equations are solved analytically using the perturbation technique. Comparisons with previously published work on special cases of the problem are performed and results are found to be in excellent agreement. The results obtained show that the velocity, temperature and concentration fields are appreciably influenced by the presence of magnetic field, thermal radiation, chemical reaction and Ohmic dissipation. It is observed that the effect of magnetic field, heat source and thermal radiation is to decrease the velocity, temperature profiles in the boundary layer. The effect of increasing the values of rarefaction parameter is to increase the velocity in the momentum boundary layer. Further, it is found that increasing the value of the chemical reaction decreases the concentration of species in the boundary layer. Also, the effects of the various parameters on the skin-friction coefficient, local Nusselt number and local Sherwood number at the surface are discussed. © Società Italiana di Fisica/Springer-Verlag 2014.

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