Karaj Islamic Azad University is probably the most populated branch of Islamic Azad University which was established in Karaj in 1984 . It started its activities with 500 students who studied in 7 fields of study. Nowadays this big university complex consists of 11 faculties, 1 high college, 1 technical college and 1 educational center and 3 research centers. In the beginning of 2011, about 30,000 students studied in this branch of Islamic Azad University. Wikipedia.
Hojabri A.,Islamic Azad University at Karaj
Journal of Theoretical and Applied Physics | Year: 2016
Zirconium oxide thin films were grown successfully by thermal annealing of zirconium thin films deposited on quartz and silicon substrates by direct current magnetron sputtering technique. The structural and optical properties in relation to thermal annealing times were investigated. The X-ray diffraction patterns revealed that structure of films changes from amorphous to crystalline by increase of annealing times in range 60–240 min. The composition of films was determined by Rutherford back scattering spectroscopy. Atomic force microscopy results exhibited that surface morphology and roughness of films depend on the annealing time. The refractive index of the films was calculated using Swanepoel’s method. The optical band gap energy of annealed films decreased from 5.50 to 5.34 eV with increasing thermal annealing time. © 2016, The Author(s).
Behravan Rad A.,Islamic Azad University at Karaj |
Behravan Rad A.,ZAMYAD Company Saipa Group
Applied Mathematics and Computation | Year: 2015
In this paper an attempt is made to investigate the thermo-elastic behavior of functionally graded (FG) circular plates embedded on gradient hybrid foundation and subjected to non-uniform asymmetric mechanical and uniform thermal loads. The supporting medium is modeled as the Horvath-Colasanti type foundation with variable coefficients in the radial and circumferential directions. The thermal environment is assumed to be uniform over the bottom and top surfaces of the plate and varies along the thickness direction only. The governing state equations are extracted in terms of displacements and temperature based on 3D theory of thermo-elasticity, and assuming the material properties of the plate except the Poisson's ratio vary continuously throughout the thickness direction according to an exponential function. These equations are solved using a semi-analytical method and some numerical results are displayed to clarify the effects of material heterogeneity indices, foundation stiffness coefficients, foundation gradient indices, loads ratio and temperature difference between the upper and lower surfaces of the plate on displacement and stress fields. The results are reported for the first time and the new results can be used as a benchmark for researchers to validate their numerical and analytical methods in the future. © 2015 Published by Elsevier Inc..
Seyf H.R.,Islamic Azad University at Karaj |
Feizbakhshi M.,Sharif University of Technology
International Journal of Thermal Sciences | Year: 2012
Numerical investigation on the application of nanofluids in Micro-Pin-Fin Heat Sinks (MPFHSs) has been presented in this paper. To investigate flow and heat transfer behavior in MPFHS the three-dimensional steady Navier-Stokes and energy equations were discretized using a finite volume approach and have been solved iteratively, using the SIMPLE algorithm. DI-water is used as a base coolant fluid while the nanoparticles used in the present study are CuO nanoparticles with mean diameters of 28.6 and 29 nm and Al 2O 3 nanoparticles with mean diameters of 38.4 and 47 nm. The results show that (i) a significant enhancement of heat transfer in the MPFHS due to suspension of CuO orAl 2O 3 nanoparticles in the base fluid in comparison with pure water, (ii) enhancement of heat transfer is intensified with increasing volume fraction of nanoparticles and Reynolds number, (iii) increasing volume fraction of nanoparticles which is responsible for higher heat transfer performance leads to higher pressure drop or Euler number in MPFHS but the enhancements are small, especially for lower particle volume fractions, (iv) with decreasing particle diameters the Nusselt number increases for Al 2O 3-water nanofluid while the trend is reverse for CuO-water nanofluid. © 2012 Elsevier Masson SAS. All rights reserved.
Lee K.-H.,Griffith University |
Farzipoor Saen R.,Islamic Azad University at Karaj
International Journal of Production Economics | Year: 2012
Despite the increased awareness of the conceptual and practical definition of corporate sustainability, questions remain on how to measure performance. The objective of this paper is to advance our understanding of the measurement of corporate sustainability management by introducing a data envelopment analysis (DEA) technique and an empirical case of a Korean electronics industry. In particular, we employ cross-efficiency in the presence of dual-role factors by reflecting some complexity of a real-world case, donations for tax benefits. By employing the combined approach of cross-efficiency and dual-role factors, we offer a new model to measure corporate sustainability management. The new model and study findings contribute to the body of knowledge in corporate sustainability management and its performance measurement. © 2011 Elsevier B.V. All rights reserved.
Ezzati R.,Islamic Azad University at Karaj
Soft Computing | Year: 2011
In this paper, the main aim is to develop a method for solving an arbitrary general fuzzy linear system by using the embedding approach. Considering the existing and uniqueness of fuzzy solution to n × n linear fuzzy system is done. Numerical examples are presented to illustrate the proposed model. © 2010 Springer-Verlag.
Shabani M.O.,Islamic Azad University at Karaj |
Mazahery A.,Islamic Azad University at Karaj
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science | Year: 2012
In this research, the effect of the volume fraction of the alumina nanoparticles on the mechanical properties of the Al-Si matrix composites was studied. The yield strength and tensile strength increase, but the elongation decreases with the increase in the volume fraction of the particles, indicating that increasing the volume fraction of the Al 2O 3 particles can improve the strength but degrade the plasticity of the composites. The mechanical properties modeling was carried out using an artificial neural network (ANN) and finite element model (FEM). The neural network was trained using different training algorithms, hidden layers, and neuron numbers in hidden layers in order to check the system accuracy of each training algorithm at the end of learning. © The Minerals, Metals & Materials Society and ASM International 2012.
Shabani M.O.,Islamic Azad University at Karaj |
Mazahery A.,Islamic Azad University at Karaj
Composites Part B: Engineering | Year: 2013
In this study, an effective approach based on genetic algorithm (GA), swarm intelligence optimization and finite element method (FEM) was implemented in order to model and optimize the process conditions of Al Matrix nano-composites. The nano-ceramic particles were added into the aluminum alloy to experimentally investigate the microstructure and mechanical behavior of metal matrix nano-composites (MMNCs). Inspired by the idea of breeding swarms, this paper proposes a GA/PSO hybrid algorithm, which combines the standard velocity and position update rules of PSO with the ideas of selection, crossover and mutation from GA. The experimental results of this project were compared with the modeled ones indicating the efficiency of the proposed model to estimate the optimal process conditions in fabrication of the nano-composite via casting. © 2012 Elsevier Ltd. All rights reserved.
Farzipoor Sean R.,Islamic Azad University at Karaj
International Journal of Advanced Manufacturing Technology | Year: 2010
In traditional models of data envelopment analysis it is assumed that decision making units do not have dual-role factors. This paper proposes a model for selecting third-party reverse logistics (3PL) provider in the presence of multiple dual-role factors. A numerical example demonstrates the application of the proposed method. © 2009 Springer-Verlag London Limited.
Malvandi A.,Islamic Azad University at Karaj |
Ganji D.D.,Babol Noshirvani University of Technology
International Journal of Thermal Sciences | Year: 2014
The current study is a theoretical investigation of the laminar flow and convective heat transfer of alumina/water nanofluid inside a circular microchannel in the presence of a uniform magnetic field. A modified two-component four-equation nonhomogeneous equilibrium model was employed for nanofluids, which fully accounted for the effect of the nanoparticle volume fraction distribution. Because of the microscopic roughness in circular microchannels and also the non-adherence of the fluid-solid interface in the presence of nanoparticle migration, known as slip condition, the Navier's slip boundary condition is considered at the walls. The results indicated that nanoparticles migrate from the heated walls (nanoparticles depletion) towards the core region of the microchannel (nanoparticles accumulation) and construct a non-uniform nanoparticles distribution. The ratio of the Brownian to thermophoretic diffusivities (NBT) has relatively significant effects both on the distribution of the nanoparticles and the convective heat transfer coefficient of nanofluids. It was further observed that for smaller nanoparticles, the nanoparticle volume fraction is more uniform and abnormal variations in the heat transfer rate vanish. Moreover, in the presence of the magnetic field, the near wall velocity gradients increase, enhancing the slip velocity and thus the heat transfer rate and pressure drop increase. © 2014 Elsevier Inc. All rights reserved.
Safari J.,Islamic Azad University at Karaj
Reliability Engineering and System Safety | Year: 2012
This paper proposes a variant of the Non-dominated Sorting Genetic Algorithm (NSGA-II) to solve a novel mathematical model for multi-objective redundancy allocation problems (MORAP). Most researchers about redundancy allocation problem (RAP) have focused on single objective optimization, while there has been some limited research which addresses multi-objective optimization. Also all mathematical multi-objective models of general RAP assume that the type of redundancy strategy for each subsystem is predetermined and known a priori. In general, active redundancy has traditionally received greater attention; however, in practice both active and cold-standby redundancies may be used within a particular system design. The choice of redundancy strategy then becomes an additional decision variable. Thus, the proposed model and solution method are to select the best redundancy strategy, type of components, and levels of redundancy for each subsystem that maximizes the system reliability and minimize total system cost under system-level constraints. This problem belongs to the NP-hard class. This paper presents a second-generation Multiple-Objective Evolutionary Algorithm (MOEA), named NSGA-II to find the best solution for the given problem. The proposed algorithm demonstrates the ability to identify a set of optimal solutions (Pareto front), which provides the Decision Maker (DM) with a complete picture of the optimal solution space. After finding the Pareto front, a procedure is used to select the best solution from the Pareto front. Finally, the advantages of the presented multi-objective model and of the proposed algorithm are illustrated by solving test problems taken from the literature and the robustness of the proposed NSGA-II is discussed. © 2012 Elsevier Ltd.