Islamic Azad University at Karaj
Karaj, Iran

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.

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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.

Shalchi-Tabrizi A.,Sharif University of Technology | Seyf H.R.,Islamic Azad University at Karaj
International Journal of Heat and Mass Transfer | Year: 2012

Effect of using Al 2O 3-water nanofluids with different volume fractions and particle diameters on generated entropy, hydrodynamic performance and heat transfer characteristics of a tangential micro-heat sink (TMHS) was numerically investigated in this research. Results indicated that considerable heat transfer enhancement is possible when using Al 2O 3-water nanofluids as coolant and clearly the enhancement improves with increasing particles concentration and decreasing particles size. However, using nanofluid has also induced drastic effects on the pumping power that increases with particles volume fraction and Reynolds number. Finally, it was found that generated total entropy decreases with increasing volume fraction and Reynolds number and decreasing particles size. © 2012 Elsevier Ltd. 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.

Seyf H.R.,Islamic Azad University at Karaj | Nikaaein B.,Islamic Azad University at Karaj
International Journal of Thermal Sciences | Year: 2012

In the present paper the thermal performance of nanofluid flow in microchannel heat sinks (MCHSs) was analyzed using three different nanofluids. The fluid flow and heat transfer in the MCHS are modeled using the Darcy-Brinkman-Forchheimer and two-equation model, respectively. In order to check the validity of the results, they were compared with available experimental and numerical data in the literature and excellent agreement was found between them. The key novelties of present work are (i) using a novel and complex temperature dependent thermal conductivity model for nanofluids, based on Brownian motion induced micro mixing, (ii) using new nanofluids with three types of nanoparticle materials i.e. aluminum oxide (Al 2O 3), zinc oxide (ZnO) and copper oxide (CuO) and 60:40 (by mass) EG-water for the base fluid, (iii) investigating the effect of nanoparticles size and Brownian motion of particles on thermal performance of MCHS. © 2012 Elsevier Masson SAS. All rights reserved.

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.

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