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Taghizadeh H.,Islamic Azad University at Shabestar | Tarafdar Hagh M.,University of Tabriz
IEEE Transactions on Industrial Electronics | Year: 2010

In this paper, the elimination of harmonics in a cascade multilevel inverter by considering the nonequality of separated dc sources by using particle swarm optimization is presented. Solving a nonlinear transcendental equation set describing the harmonic-elimination problem with nonequal dc sources reaches the limitation of contemporary computer algebra software tools using the resultant method. The proposed approach in this paper can be applied to solve the problem in a simpler manner, even when the number of switching angles is increased and the determination of these angles using the resultant theory approach is not possible. Theoretical results are verified by experiments and simulations for an 11-level H-bridge inverter. Results show that the proposed method does effectively eliminate a great number of specific harmonics, and the output voltage is resulted in low total harmonic distortion. © 2010 IEEE.

Paknezhad A.,Islamic Azad University at Shabestar | Dorranian D.,Islamic Azad University at Tehran
Physics of Plasmas | Year: 2013

This article studies the nonlinear Raman shifted third harmonic backscattering of an intense extraordinary laser wave through a homogenous transversely magnetized cold plasma. Due to the relativistic nonlinearity, the plasma dynamic is modified in the presence of transversely magnetic field, and this can generate the third harmonic scattered wave and an electrostatic upper hybrid wave via the Raman scattering process. Using the nonlinear wave equation, the mechanism of nonlinear third harmonic Raman scattering is discussed in detail to obtain the maximum growth rate of instability in the mildly relativistic regime. The growth rate decreases as the static magnetic field increases. It also increases with the pump wave amplitude. © 2013 AIP Publishing LLC.

Ghiasi Ghalehkandi J.,Islamic Azad University at Shabestar
Animal Reproduction | Year: 2014

Semen oxidation is one of the major testimonies of infertility. The aim of present study was to examine the effects of fresh garlic juice on semen malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPx) and total antioxidant status (TAS) compared with chromium chloride (CrCl3) in male rats. A hundred and sixty-two male rats were allocated into 9 treatment groups. Group 1 served as control. In group 2, rats gavage 60 mg/kg garlic juice. In group 3, rats were offered 120 mg/kg garlic juice. Group 4 drenched 4 mg/kg CrCl3. In group 5, 8 mg/kg CrCl3 was offered to rats. Group 6 was treated with 60 mg/kg garlic juice + 4 mg/kg CrCl3. Group 7 gavage 60 mg/kg garlic juice + 8 mg/kg CrCl3. Group 8 consumed 120 mg/kg garlic juice + 4 mg/kg CrCl3. In group 9 rats received 8 mg/kg CrCl3 + 120 mg/kg garlic juice. After 4 weeks animals were killed and semen samples used to determine MDA, SOD, GPx and TAS activity. According to the results, garlic juice (120 mg/kg) significantly declined semen MDA activity compared to control group (P < 0.05). Also, garlic juice (120 mg/kg) significantly attenuated effects of CrCl3 on TAS compared to control group (P < 0.05). These results suggest that garlic juice presumably protects semen oxidation in rat testes.

This paper studies the Brillouin scattering of an intense short laser pulse in an underdense homogenous plasma by taking into account higher orders of relativistic nonlinearities. The coupled dispersion relations of stimulated Brillouin scattering are obtained in the weakly and strongly coupled regimes and investigated analytically to find the nonlinear temporal growth rate of instability in forward and backward scatters. It is shown that, for both the regimes, the Brillouin backward scattering growth rate increases due to the relativistic nonlinearity. © 2012 The Royal Swedish Academy of Sciences.

Malekzadeh S.,University of Yazd | Malekzadeh S.,Islamic Azad University at Shabestar | Sohankar A.,Isfahan University of Technology
International Journal of Heat and Fluid Flow | Year: 2012

This study focuses on the reduction of the fluid forces acting on a square cylinder in a laminar flow regime by a passive control, i.e. a flat plate placed upstream of the cylinder. The Reynolds numbers based on the width of the square cylinder (W) and the inlet flow velocity are selected from Re = 50 to Re = 200. The width of the control plate (h) is varied from 0.1. W to 0.9. W and the distance between the control plate and the cylinder (S) is chosen within the range of 1.1-7. W. In these ranges of h and S, the different flow patterns and the magnitude of the reduction of the fluid forces in order to identity the optimum conditions are studied. The results of the heat transfer from a cylinder in the presence of a control plate are also provided for S= 1.1-7. W, h= 0.5-0.9. W, Re = 160, Pr = 0.71. The results show that the optimum position and width for the control plate are a distance of 3. W away from the cylinder and a width of 0.5. W, respectively, where the almost maximum reduction of the fluid forces and the minimum reduction of the heat transfer are provided. It is also found that the total Nusselt number of the cylinder in the presence of the control plate decreases for different gap spacings, except for S/. W= 1.1. © 2011 Elsevier Inc.

Movassagh M.H.,Islamic Azad University at Shabestar
Journal of Food Safety | Year: 2011

Mycotoxins in milk is a public health concern and has to be regularly monitored. The role of milk in human nutrition is well known. The aim of this study was to evaluate aflatoxin M1 (AFM1) contamination in ultra-high-temperature (UHT) milk samples in Tabriz city (Iran) by enzyme-linked immunosorbent assay. Forty-nine UHT milk samples from different supermarkets in Tabriz city were collected during 6 months (July to December 2008). AFM1 was found in 100% of the examined milk samples; 83.67% of the samples had AFM1 greater than the maximum tolerance limit (50ng/L) accepted by European Union. It can be concluded that AFM1 levels in the samples purchased in Tabriz city appear to be a serious public health problem at the moment and is much higher than some other countries. © 2011 Wiley Periodicals, Inc.

Sadri Y.,Islamic Azad University at Shabestar | Khanmohamadi S.,University of Tabriz
Journal of Supercomputing | Year: 2013

The appearance of media applications with high bandwidth and quality of service requirements has made a significant impact in telecommunications technology. In this direction, the IEEE802.16 has defined wireless access systems called WiMAX. These systems provide high-speed communications over a long distance. For this purpose some service classes with QoS requirements are defined; but the QoS scheduler is not standardized in IEEE802.16. The scheduling mechanism has a significant effect on the performance of WiMAX systems for use of bandwidth and radio resources. Some scheduling algorithms have been introduced by researchers; but they only provide some limited aspects of QoS. An intelligent decision support system is therefore necessary for scheduling. In this paper a fuzzy based scheduling system is proposed for compounds of real-time and non-real-time polling services which provide QoS requirements and fairness in dynamic conditions. A series of simulation experiments have been carried out to evaluate the performance of the proposed scheduling algorithm in terms of latency and throughput QoS parameters. The results show that the proposed method performs effectively regarding both of these criteria and achieves proportional system performance and fairness among different types of traffic. © 2010 Springer Science+Business Media, LLC.

According to abundance of energy resources in Iran, fuel consumption has risen to high levels in recent years turning into a dominant concern for the government forcing it to speculate on new approaches for reduction of it. One of the major policies is the policy of fuel management which has led to implementation of diverse plans and actions. In this paper, the intention is analyze energy consumption rate in transportation sector of Iran and introduce the strategies devised to reduce it. The methods of implementation of these policies arising from these policies along with the achievements have also been introduced and analyzed. © 2011 Published by Elsevier Ltd.

The present paper attempts to determine the properties of photonic spectra of Thue-Morse, double-period and Rudin-Shapiro one-dimensional quasiperiodic multilayers. The supposed structures are constituted by high temperature HgBa2Ca2Cu3O10 and YBa2Cu3O7 superconductors. Our investigation is restricted to the visible wavelength domain. The results are demonstrated by the calculation of transmittance using transfer matrix method together with Gorter-Casimir two-fluid model. It is found that by manipulating the parameters such as incident angle, polarization, the thickness of each layer and operation temperature of superconductors the transmission spectra exhibit some interesting features. This paper, provides us a pathway to design tunable total reflector, optical filters and optical switching based on superconductor quasiregular photonic crystals. © 2016 Elsevier B.V. All rights reserved.

Paknezhad A.,Islamic Azad University at Shabestar
Laser and Particle Beams | Year: 2013

Brillouin backward scattering is investigated in the interaction of linearly polarized short laser pulse with a homogenous underdense transversely magnetized plasma by taking into account the relativistic and nonlinearity effects up to third order. The plasma is embedded in a uniform magnetic field perpendicular to both of propagation direction and electric vector of the radiation field. Temporal growth rate of instability is calculated by using of the nonlinear wave equation. Results are significantly different in comparison with lower order computations. The growth rate of Brillouin backward instability shows a decrease due to the presence of external magnetic field, while relativistic and higher order nonlinearities due to the external magnetic field, give rise the Brillouin backward scattering instability. Copyright © Cambridge University Press 2013.

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