Hamidi S.,Islamic Azad University at Sanandaj Branch |
Kermani M.J.,Amirkabir University of Technology
European Journal of Mechanics, B/Fluids | Year: 2013
Numerical solutions of a compressible two-phase two-component moist-air flow with and without shock waves are investigated in this paper using the high resolution flux difference splitting scheme of Roe (1981) . The solver is spatially third order and temporally second order accurate. The flow is assumed to obey an equilibrium thermodynamic model. For the two-phase flow in dry regions, the pressure (P), temperature (T), and velocity (u) are extrapolated to the cell faces by the MUSCL approach, while in wet regions the steam quality (χ) has been used instead of pressure. Comparisons of the wetness fraction at the nozzle exit show that in the case of moist-air flow rather than pure steam, a much higher wetness fraction, about 30%, can be achieved, while in the case of pure steam and under similar conditions the wetness fraction is limited to about 6%. The present study gives a practical guideline in the production of liquid water in a much higher rate, if an additive gas (like air) is added to steam. Hence it can be used as an alternative approach to produce potable water from atmospheric air in geographically humid regions. For moist-air flow with normal shock, the results show that across the shock the liquid phase rapidly evaporates. © 2013 Elsevier Masson SAS. All rights reserved.
Nouri H.,Islamic Azad University at Sanandaj Branch |
Hong T.S.,University Putra Malaysia
Journal of Manufacturing Systems | Year: 2013
The cellular manufacturing system (CMS) is considered as an efficient production strategy for batch type production. The CMS relies on the principle of grouping machines into machine cells and grouping machine parts into part families on the basis of pertinent similarity measures. The bacteria foraging optimization (BFO) algorithm is a modern evolutionary computation technique derived from the social foraging behavior of Escherichia coli bacteria. Ever since Kevin M. Passino invented the BFO, one of the main challenges has been the employment of the algorithm to problem areas other than those of which the algorithm was proposed. This paper investigates the first applications of this emerging novel optimization algorithm to the cell formation (CF) problem. In addition, for this purpose matrix-based bacteria foraging optimization algorithm traced constraints handling (MBATCH) is developed. In this paper, an attempt is made to solve the cell formation problem while considering cell load variations and a number of exceptional elements. The BFO algorithm is used to create machine cells and part families. The performance of the proposed algorithm is compared with a number of algorithms that are most commonly used and reported in the corresponding scientific literature such as K-means clustering, the C-link clustering and genetic algorithm using a well-known performance measure that combined cell load variations and a number of exceptional elements. The results lie in favor of better performance of the proposed algorithm. © 2012 The Society of Manufacturing Engineers. Published by Elsevier Ltd. All rights reserved.
Shokrollahi B.,Islamic Azad University at Sanandaj Branch
Genetics and molecular research : GMR | Year: 2012
The objective of the present study was to estimate genetic parameters for body weight at different ages in Arabi sheep using data collected from 1999 to 2009. Investigated traits consisted of birth weight (N = 2776), weaning weight (N = 2002) and weight at six months of age (N = 1885). The data were analyzed using restricted maximum likelihood analysis, by fitting univariate and multivariate animal models. All three weight traits were significantly influenced by birth year, sex and birth type. Age of dam only significantly affected birth weight. Log-likelihood ratio tests were conducted to determine the most suitable model for each growth trait in univariate analyses. Direct and total heritability estimates for birth weight, weaning weight and weight at six months of age (based on the best model) were 0.42 and 0.16 (model 4), 0.38 and 0.13 (model 4) and 0.14 and 0.14 (model 1), respectively. Estimation of maternal heritability for birth weight and weaning weight was 0.22 and 0.18, respectively. Genetic and phenotypic correlations among these traits were positive. Phenotypic correlations among traits were low to moderate. Genetic correlations among traits were positive and higher than the corresponding phenotypic correlations. Weaning weight had a strong and significant correlation with weight at six months of age (0.99). We conclude that selection can be made in animals based on weaning weight instead of the present practice of selection based on weight at six months.
Refaei A.,Razi University |
Refaei A.,Islamic Azad University at Sanandaj Branch |
Takook M.V.,Razi University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2011
The one-loop effective action of QED is calculated by the Schwinger method in Krein space quantization. We show that the effective action is naturally finite and regularized. It also coincides with the renormalized solution which was derived by Schwinger. © 2011 Elsevier B.V.
Sheikhahmadi H.,University of Kurdistan |
Aghamohammadi A.,Islamic Azad University at Sanandaj Branch |
Saaidi K.,University of Kurdistan
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2015
In this work, the effects of non-commutative and commutative vacua on the phase space generated by a scalar field in a scalar torsion scenario are investigated. For both classical and quantum regimes, the commutative and non-commutative cases are compared. To take account the effects of non-commutativity, two well known non-commutative parameters, θ and β, are introduced. It should be emphasized, the effects of β which is related to momentum sector has more key role in comparison to θ which is related to space sector. Also the different boundary conditions and mathematical interpretations of non-commutativity are explored. © 2015 The Authors.
Ahmadizar F.,University of Kurdistan |
Soltanpanah H.,Islamic Azad University at Sanandaj Branch
Expert Systems with Applications | Year: 2011
This paper deals with a reliability optimization problem for a series system with multiple-choice and budget constraints. The objective is to choose one technology for each subsystem in order to maximize the reliability of the whole system subject to the available budget. This problem is NP-hard and could be formulated as a binary integer programming problem with a nonlinear objective function. In this paper, an efficient ant colony optimization (ACO) approach is developed for the problem. In the approach, a solution is generated by an ant based on both pheromone trails modified by previous ants and heuristic information considered as a fuzzy set. Constructed solutions are not guaranteed to be feasible; consequently, applying an appropriate procedure, an infeasible solution is replaced by a feasible one. Then, feasible solutions are improved by a local search. The proposed approach is compared with the existing metaheuristic available in the literature. Computational results demonstrate that the approach serves to be a better performance for large problems. © 2010 Elsevier Ltd. All rights reserved.
Piltan M.,Islamic Azad University at Sanandaj Branch
Chinese Chemical Letters | Year: 2014
A simple synthetic protocol has been developed involving the three-component reaction between 1,2-diamines, ethyl pyruvate and α-bromo ketones in the presence of FeCl3 as a catalyst. A number of pyrrolo[1,2-a]quinoxaline and pyrrolo[1,2-a]pyrazine derivatives were synthesized in excellent yields using this protocol. © 2014 Mohammad Piltan. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
Karami K.,University of Kurdistan |
Fahimi K.,Islamic Azad University at Sanandaj Branch
Classical and Quantum Gravity | Year: 2013
We study the correspondence between the interacting viscous ghost dark energy model with the tachyon, K-essence and dilaton scalar field models in the framework of Einstein gravity. We consider a spatially non-flat FRW universe filled with interacting viscous ghost dark energy and dark matter. We reconstruct both the dynamics and potential of these scalar field models according to the evolutionary behavior of the interacting viscous ghost dark energy model, which can describe the accelerated expansion of the universe. Our numerical results show that the interaction and viscosity have opposite effects on the evolutionary properties of the ghost scalar field models. © 2013 IOP Publishing Ltd.
Aghamohammadi A.,Islamic Azad University at Sanandaj Branch
Astrophysics and Space Science | Year: 2014
We try to study the corresponding relation between f(T) gravity and holographic dark energy (HDE). A kind of energy density from f(T) is introduced which has the same role as HDE density. A f(T) model according to the HDE model is calculated. We find out a torsion scalar T based on the scalar factor is assumed by Capoziello et al. (Phys. Lett. B 639:135, 2006). The effective torsion equation of state, deceleration parameter of the holographic f(T)-gravity model are calculated. © 2014 Springer Science+Business Media Dordrecht.
Golpira H.,University of Kurdistan |
Bevrani H.,University of Kurdistan |
Golpira H.,Islamic Azad University at Sanandaj Branch
Energy Conversion and Management | Year: 2011
This paper addresses a realistic model for automatic generation control (AGC) design in an interconnected power system. The proposed scheme considers generation rate constraint (GRC), dead band, and time delay imposed to the power system by governor-turbine, filters, thermodynamic process, and communication channels. Simplicity of structure and acceptable response of the well-known integral controller make it attractive for the power system AGC design problem. The Genetic algorithm (GA) is used to compute the decentralized control parameters to achieve an optimum operating point. A 3-control area power system is considered as a test system, and the closed-loop performance is examined in the presence of various constraints scenarios. It is shown that neglecting above physical constraints simultaneously or in part, leads to impractical and invalid results and may affect the system security, reliability and integrity. Taking to account the advantages of GA besides considering a more complete dynamic model provides a flexible and more realistic AGC system in comparison of existing conventional schemes. © 2011 Elsevier Ltd All rights reserved.