Ahmadi Fouladi A.,Islamic Azad University at Sari
Physica E: Low-Dimensional Systems and Nanostructures | Year: 2017
Based on the tight-binding model and a generalized Green's function method, we theoretically investigated the electron transport properties of T-shaped silicene nanoribbons (TsSiNRs) structure composed of an armchair SiNR (ASiNR) with a sidearm connected to two semi-infinite ASiNR leads. In particular, we demonstrated that the transport properties sensitively depend on the sidearm width and length. Besides, we found that the metal to semiconductor transition occurs with the increase of the spin-orbit interaction (SOI) strength. The effect of the external perpendicular electric field on electron transport is also investigated and it is found that potential energy causes to the decrease of the energy gap leading to semiconductor to metallic transition. © 2017 Elsevier B.V.
Rahmani Y.,Islamic Azad University at Sari
Annals of Nuclear Energy | Year: 2017
The present paper proposes application of the genetic algorithm (GA) and the innovative weighting factor method to optimize the reloading pattern of Bushehr VVER-1000 reactor in the second cycle. To estimate the composition of fuel assemblies remaining from the first cycle and precisely calculate the objective parameters of each reloading pattern in the second cycle, coupling of WIMSD5-B and CITATION-LDI2 codes in the neutronic section and the WERL code in the thermo-hydraulic section was employed. Optimization of the reloading patterns was carried out in two states. To meet the mentioned objective, with application of the weighting factor method in the first state, the type and quantity of the loadable fresh assemblies were determined to enable the reactor core to maintain the core criticality over the entire cycle length. Afterwards, the genetic algorithm was used to optimize the reloading pattern of the reactor to obtain an arrangement with flat radial power distribution. In the second state, the optimization algorithm was free to select the type and number of fresh fuel assemblies to be able to search for an arrangement with the maximum effective multiplication factor and the safe power peaking factor. In addition, in order to ensure the safety and desirability of the proposed patterns in both states, a time-dependent examination of the thermo-neutronic behavior of the reactor core was carried out during the second cycle. With consideration of the new solutions proposed in this research to increase the precision, speed, and scope of the searches and the structural constraints on reloading pattern optimization calculations, it seems that the present paper is a novel step toward the optimization of the reloading patterns of nuclear reactors. © 2017 Elsevier Ltd
Ghasemi S.E.,Islamic Azad University at Sari
Journal of Molecular Liquids | Year: 2017
In this study a simple and highly accurate semi-analytical method called the Differential Transformation Method (DTM), is used for solving the governing equations of peristaltic nanofluid flow in drug delivery systems. The effects of thermophoresis and Brownian motion parameters on temperature and velocity fields are discussed in details. The validity of the results of DTM solution are verified via comparison with numerical results obtained using fourth order Runge-Kutta method. The results show that by increasing the Brownian motion and thermophoresis parameters the temperature profile increases. Also, results reveal that DTM is very effective and convenient. Furthermore, it is found that this method can be easily extended to other strongly nonlinear heat transfer equations and can be found widely applicable in engineering and science. © 2017 Elsevier B.V.
Nozari K.,Islamic Azad University at Sari |
Pedram P.,Islamic Azad University at Tehran
Europhysics Letters | Year: 2010
In this paper we study the effects of the Generalized Uncertainty Principle (GUP) on the spectrum of a particle that is bouncing vertically and elastically on a smooth reflecting floor in the Earth's gravitational field (a quantum bouncer). We calculate energy levels and corresponding wave functions of this system in terms of the GUP parameter. We compare the outcomes of our study with the results obtained from elementary quantum mechanics. A potential application of the present study is discussed finally. Copyright © EPLA, 2010.
Yang X.-S.,University of Cambridge |
Hosseini S.S.S.,Islamic Azad University at Sari |
Gandomi A.H.,Islamic Azad University at Tehran
Applied Soft Computing Journal | Year: 2012
The growing costs of fuel and operation of power generating units warrant improvement of optimization methodologies for economic dispatch (ED) problems. The practical ED problems have non-convex objective functions with equality and inequality constraints that make it much harder to find the global optimum using any mathematical algorithms. Modern optimization algorithms are often meta-heuristic, and they are very promising in solving nonlinear programming problems. This paper presents a novel approach to determining the feasible optimal solution of the ED problems using the recently developed Firefly Algorithm (FA). Many nonlinear characteristics of power generators, and their operational constraints, such as generation limitations, prohibited operating zones, ramp rate limits, transmission loss, and nonlinear cost functions, were all contemplated for practical operation. To demonstrate the efficiency and applicability of the proposed method, we study four ED test systems having non-convex solution spaces and compared with some of the most recently published ED solution methods. The results of this study show that the proposed FA is able to find more economical loads than those determined by other methods. This algorithm is considered to be a promising alternative algorithm for solving the ED problems in practical power systems. © 2011 Elsevier B.V. All rights reserved.
Farsi M.,Islamic Azad University at Sari
Journal of Reinforced Plastics and Composites | Year: 2010
This study deals with the effect of chemical modification of wood flour by components including alkaline, silane, acrylic acid and benzoyl chloride, and PP-g-MA coupling agent concentration (0 and 3 wt%) on the mechanical performance of WPCs. The samples were fabricated by melt compounding in an internal mixer and then injection molding. Tensile, flexural, and Izod impact test of modified composites were performed and compared by net polypropylene and unmodified samples. The results showed that the highest tensile and flexural resistance was observed in composites modified with alkaline and including coupling agent. Modified composites had lower impact strength than unmodified ones. Simultaneous use of chemical modification and coupling agent on mechanical properties had synergic effect. Therefore, chemical modification of wood flour improved interfacial adhesion and so increased the mechanical performance of these composites. © 2010 The Author(s).
Darvishi Khezri H.,Islamic Azad University at Sari
Saudi journal of kidney diseases and transplantation : an official publication of the Saudi Center for Organ Transplantation, Saudi Arabia | Year: 2014
Poor sleep quality is a common problem that can potentially predict mortality risk and quality of life in hemodialysis (HD) patients. Also, inflammation is a common feature in HD patients. To determine sleep quality and its correlation with serum C-reactive protein (CRP) level in these patients, we studied 132 chronic HD patients in two university-affiliated teaching hospitals in Sari, Iran during September 2010. Pittsburgh Sleep Quality Index was employed to assess the sleep quality of the patients in addition to CRP, albumin, cholesterol, phosphorus and hemoglobin levels. There were 104 (78.7%) patients who suffered from poor sleep quality. A significant correlation was found between serum CRP level and the patients' sleep quality (P <0.05). There was also a significant correlation between sleep quality and serum phosphorus and albumin levels and body mass index (P <0.05). Furthermore, a significant positive correlation existed between the different components of sleep quality and CRP (P <0.05). We conclude that there is a correlation between decreased sleep quality in HD patients and elevated CRP levels, which may have therapeutic implications.
Farsi M.,Islamic Azad University at Sari
Fibers and Polymers | Year: 2012
The objective of this investigation was to evaluate the mechanical, thermal stability and viscoelastic behaviors of experimental PP composites made from wheat straw and PP-g-MA coupling agent. Four levels of wheat straw, 10, 20, 25 and 30 wt % and two levels of coupling agent, 0 and 3 % wt were mixed with PP in rotary type mixer and injection molding process, respectively. Tensile characteristics and impact strength, thermal gravity and dynamic mechanical and thermal analysis of the samples were evaluated. Based on the results, it was observed that the tensile properties increased and impact strength decreased with the increase in the fiber loading from 10 % to 30 %. Further, the composites treated with PP-g-MA exhibited improved mechanical properties which confirmed efficient fiber-matrix adhesion. DMT analysis showed that the PP composites made of 30 % wheat straw containing 3 % PP-g-MA showed the highest E' and lowest tan δ than the untreated ones. Also, the thermal stability of wheat straw was lower than PP and as filler content in the composites increased, the thermal stability decreased and the ash content increased. © 2012 The Korean Fiber Society and Springer Netherlands.
Moradi S.E.,Islamic Azad University at Sari
Journal of Industrial and Engineering Chemistry | Year: 2014
Highly ordered mesoporous carbon (OMC) has been prepared and modified with a anionic surfactant sodium dodecyl sulphate (SDS) by microwave heating technique and used as an efficient sorbent for methylene blue (MB) dye removal from wastewater. The structural order and textural properties of the adsorbents was studied by XRD, BET, FT-IR, Raman and TGA analyses. Adsorption experiments were conducted in batch mode with the variables such as amount of adsorbent, agitation speed, contact time, temperature, initial solution concentration and solution pH. The MB dye removal for microwave and impregnation methods modified SDS-OMC and OMC were found to be 95.3, 88.4 and 68%, respectively. © 2013 The Korean Society of Industrial and Engineering Chemistry.
Mollaiy Berneti S.,Islamic Azad University at Sari
International Journal of Computational Intelligence Systems | Year: 2013
In this paper, a novel hybrid approach composed of adaptive neuro-fuzzy inference system (ANFIS) and imperialist competitive algorithm is proposed. The imperialist competitive algorithm (ICA) is used in this methodology to determine the most suitable initial membership functions of the ANFIS. The proposed model combines the global search ability of ICA with local search ability of gradient descent method. To illustrate the suitability and capability of the proposed model, this model is applied to predict oil flow rate of the wells utilizing data set of 31 wells in one of the northern Persian Gulf oil fields of Iran. The data set collected in a three month period for each well from Dec. 2002 to Nov. 2010. For the sake of performance evaluation, the results of the proposed model are compared with the conventional ANFIS model. The results show that the significant improvements are achievable using the proposed model in comparison with the results obtained by conventional ANFIS. © 2013 Copyright the authors.