فهرست مطالب

International Journal of Engineering
Volume:30 Issue: 3, Mar 2017

  • Transactions C : Aspects
  • تاریخ انتشار: 1395/12/20
  • تعداد عناوین: 15
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  • R. Rostamani, S. S. Ashraf Talesh Page 330
    The particle size control of drug is one of the most important factors affecting the efficiency of the nano-drug production in confined liquid impinging jets. In the present research, for this investigation the confined liquid impinging jet was used to produce nanoparticles of Carbamazepine. The effects of several parameters such as concentration, solution and anti-solvent flow rate and solvent type were investigated. So far no analytical and acceptable model has been provided to predict the Carbamazepine particle size in confined liquid impinging jets. In this study the variables affecting the size of the particle became dimensionless using the dimensional analysis then by solving the equation with singular value decomposition method, a simple dimensionless relation was obtained for this process. Moreover, using the genetic algorithm the coefficients of dimensionless parameters were optimally extracted to minimize the error between the model and the laboratory outputs. The determination coefficient of the equation obtained by singular value decomposition method and the improved equation using genetic algorithm were obtained as 0.5291 and 0.5697, respectively. For such a complex experimental system, the accuracy of the obtained equations in spite of their simplicity is acceptable. The obtained results were compared with the results of the neural network model. The results showed that despite the higher precision of the obtained relations by the neural network, the relations obtained by singular value decomposition can be used as a simple method using the dimensionless parameters with acceptable acuracy to predict the particle size in confined liquid impinging jets.
    Keywords: CLIJ, SVD, Genetic algorithms, nano, drugs
  • S. Jarchi, O. Soltan, Mohammadi, J. Rashed, Mohassel Page 338
    In this paper, an ultra-wideband metamaterial absorber is designed and simulated. The proposed absorber is planar and low profile. It is made of a copper sheet coated with two dielectric layers. Each unit cell of the metamaterial structure is composed of multiple metallic split rings, which are patterned on the top and middle boundaries of the dielectrics. The designed absorber utilizes different resonances of the split rings with non-identical parameters. In order to achieve ultra-wideband absorption, dimensions of the rings are designed to represent dissimilar nearby resonant frequencies. An ultra-wide bandwidth of 67% for 85% absorption is achieved. The absorber’s performance is investigated for TE and TM polarizations, and with varying incidence and polarization angles. Ultra-wide band performance of the structure for the case of normal incidence changes to multi-band absorption, with increasing the incidence angle. Electric field distribution of the rings for three low, middle and high frequencies in the absorption bandwidth is simulated and graphically demonstrated. The field distribution verifies that the rings with larger dimensions interact more effectively with low frequency electromagnetic waves, and the rings with smaller dimensions have stronger effects on high frequency waves.
    Keywords: metamaterial absorber, wide, band absorber, planar metamaterial
  • Z. S. Tabatabaeian, M. H. Neshati Page 344
    In this paper a new procedure for designing forward-wave directional couplers using periodic shunt short circuited stubs is proposed. A new type of cell using these stubs, which enlarge the phase difference between even- and odd modes of a uniform microstrip coupled line is introduced. Using the equivalent circuit model for even- and odd-modes of the proposed cell, the elements of the ABCD transmission matrix of the cell are derived. The design procedure of the Forward-Wave Directional Couplers (FWDC) is disccused using the equivalent circuit model. To verify the accuracy of the proposed method, three FWDCs with different levels of coupling are designed and studied at the central frequency of 1.5 GHz. The couplers are numerically simulated using High Frequency Structure Simulator (HFSS) and the results including S-paramerters, coupling level and the overall bandwidth are compared with those obtained by equivalent circuit model. Moreover, a prototype of the proposed 0 dB coupler is made using a single layer of substrate and it is succesfully tested. Measured results show that 0.62 dB level of coupling is obatined with 1 dB flatness from 1.45 GHz to 1.63 GHz, which corresponds to 11.7% fractional bandwidth and the length of the fabricated coupler is 0.26λg.
    Keywords: Forward, wave directional coupler, periodic structures, Bloch impedance, transmission matrix.
  • H. Moradi Cheshmehbeigi, A. Khanmohamadian Page 351
    The Electromagnetic Aircraft Launch System (EMALS) offers significant benefits to the aircraft, ship, personnel, and operational capabilities. EMALS has such advantages as high thrust, good controllability, reusable, etc., as a launching motor, a double-side plate Permanent Magnet Linear Synchronous Motor (PMLSM) can provide high instantaneous thrust. This paper presents the design and analysis of the moving-magnet-type permanent magnet linear synchronous motor (PMLSM). A detailed analytical modeling based on Maxwell’s equations is presented for analysis and design of PMLSM with Halbach array. In order to improve the thrust characteristics of PMLSM, the structural characteristics and magnetic field are analyzed. The results show an enhancement in the motor performance. Finally, we have used 2-D nonlinear time-stepping transient finite element method to demonstrate validity of the analytical analysis and parametric search is used for multi-objective optimization of PMLSM. Using Finite Element Analysis (FEA), the effects of the parameters on the thrust and thrust ripple waveforms are analyzed.
    Keywords: EMALS, LHRM, double, sided, FEA, magnetic field analysis
  • M. Hamidian, A. R. Sedighi Page 357
    Increased electric energy consumption in recent years, associated economic problems, reduced reliability and increased power losses in electric networks. One of the main solutions in smart grids to overcome the mentioned problems is demand response programs. In demand response programs, operators apply time-varying tariffs to consumers, and convince them to change their consumption pattern. Among the demand response programs, the most effective program for subscribers who receive electricity at fixed price is time-of-use (TOU) pricing. This paper offers a new approach to implementing TOU program, which is determining the scheduling and pricing of TOU tariff simultaneously taking into account the objectives of smoothing the load profile, reducing the losses and energy not supplied. The proposed method is simulated in MATLAB, and has been evaluated on an urban distribution network in Yazd Electrical Distribution Company (YEDC) that feeds 35 distribution transformers (20/0.4kV) through a radial feeder. Results show that implementation of this method has only a minor increase in cost and reduction in consumption for subscribers, and makes load profile more smooth, improve reliability and reduce power losses.
    Keywords: TOU, Daily Load Profile, Power Losses, ENS, Electric Distribution System, Genetic Algorithm
  • M. Zarean, F. Teimouri, M. Moazeni, A. Ebrahimi Page 366
    The purpose of the current study is to evaluate formaldehyde degradation ratio with various methods in a batch reactor. In this work, the ozonation, sonolysis (ultrasonic), and ozone sonolysis, sono catalytic ozonation (SCO), and nano zero-valent iron catalyst processes were investigated for removal of formaldehyde. In addition, the influence of important factors such as pH (5–9), ultrasonic power (60-140 W), ozone dosage (20–200 mg hr-1), NZVI dosage (50-400 mg L-1), and initial HCHO concentration (1–20 mg L-1) were tested. The results demonstrated that the SCO process was the most efficient one amongst the process considered. The effect of important factors were also tested on the efficiency of the SCO process and maximum removal (99%) was found at a pH of 5, ultrasonic power of 100 W, ozone dosage of 200 mg hr-1, catalyst dosage of 200 mg L-1 and initial formaldehyde concentration of 15 mg L-1. The results led to the conclusion that the most effective factor was ozone dosage. Also, SCO process may be recommended for the treatment of solutions containing low formaldehyde concentrations.
    Keywords: Ozone, formaldehyde, zero, valent iron, advanced oxidation process, sonolysis
  • M. Ghomi-Avili, R. Tavakkoli-Moghaddam, G. Jalali, A. Jabbarzadeh Page 374
    This paper develops a model for the closed-loop supply chain network design with disruption risk. By considering supply disruption, two factors including extra inventory and lateral transshipment are used as resilience strategies. The main purpose is to reduce the supply chain costs due to the location decisions, quantity of products between different levels and lost sale. Disruption in a supply is assumed completely by different scenarios, and then the problem is formulated by a mixed-integer programming model. Furthermore, a two-stage stochastic approach is implemented to tackle uncertainty. Finally, a sensitivity analysis is carried out to examine the effects of the resilience strategies on the structure of the supply chain and to propose some managerial insight for using the model in real world situations.
    Keywords: Closed, loop supply chaim, Disruption: Resilience strategies, Uncertainty
  • A. Hashemoghli, I. Mahdavi, A. Tajdin Page 384
    Elaborating an appropriate cellular manufacturing system (CMS) could solve many structural and operational issues. Thereby, considering some significant factors as worker skill, machine hardness, and product quality levels could assist the companies in current competitive environment. This paper proposes a novel interactive possibilistic mixed integer nonlinear approach to minimize the total costs of cellular manufacturing design. The proposed approach is elaborated regarding operation sequence, worker and machine assignments, route and worker flexibility, machine hardness level, worker and machine capacity, worker skill level, and product quality level based on imprecise information. Meanwhile, the product demand parameter because of its nature is defined based on fuzzy setting environment. Then, the interactive possibilistic approach is provided to cope with the existed uncertainty according to the problem environment. Finally, a numerical experiment is considered to show the capability of the proposed approach. The results of the proposed interactive possibilistic model show that the presented approach could assist companies for minimizing their costs and manipulating the machines and workers’ suitability. In this respect, comparing the obtained results from the proposed approach and similar circumstances shows that the proposed model could reduce the total costs by 27.8%.
    Keywords: Cellular manufacturing problem, Possibilistic approach, Interactive fuzzy approach, worker skill, flexibility
  • N. Neshat, M. R. Amin-Naseri, H. Shakouri Ganjavi Page 393
    Intensified industrialization in developing countries has recently resulted in huge electric power demand growth; however, electricity generation in these countries is still heavily reliant on inefficient and traditional non-renewable technologies. In this paper, we develop an integrated game-theoretic model for effective power systems planning thorough balancing between supply and demand for electricity markets in transition. In this regard, a Case Study of Iran’s power system is used to illustrate the usefulness of the proposed planning approach and also to discuss its efficiency. Sectoral electricity demands of Iran`s power system as nonlinear functions are forecasted by applying times series approach while general information on economical, technological, political and electricity market conditions of sectors is also given. The brief look into the planning results shows that the proposed approach provides not only competitive conditions for renewable technologies expansion but also a robust one compared to the traditional (cost-based) approach.
    Keywords: Sustainable Energy Systems Planning, Renewable Technologies, Game Theory, Forecasting
  • E. Nasiri, A. J. Afshari, M. Hajiaghaei-Keshteli Page 403
    Nowadays, in global free market, third-party logistics providers (3PLs) are becoming increasingly important. Hence, this study aims to develop the freight consolidation and containerization problem, which consists of loading items into containers and then shipping these containers to different warehouse they are delivered to their final destinations. In order to handle the proposed problem, this research not only uses the traditional and recent algorithms, but also the two new hybridized methods are introduced in order to strengthen the advantages of recent ones. In this regard, this study considers the two important phases in meta-heuristic to develop new ones. Besides, Taguchi experimental design method is utilized to set and estimate the proper values of the algorithms’ parameters to improve their performance. For the purpose of performance evaluation of the proposed algorithms, various problem sizes are employed and the computational results of the algorithms are compared with each other. Finally, the impacts of the rise in the problem size on the performance of the proposed algorithms are investigated.
    Keywords: Freight consolidation, containerization problem, Red Deer algorithm, Stochastic Fractal search, Hybridized methods, Intensification, diversification phases
  • P. Samoei, V. Khodakarami, P. Fattahi Page 411
    This paper presents a multi-objective simulated annealing algorithm for the mixed-model assembly line balancing with stochastic processing times. Since, the stochastic task times may have effects on the bottlenecks of a system, maximizing the weighted line efficiency (equivalent to the minimizing the number of station), minimizing the weighted smoothness index and maximizing the system reliability are considered. After solving an example in detail, the performance of the proposed algorithm is examined on a set of test problems. The experimental results show the new approach performs well.
    Keywords: assembly line balancing, reliability, mixed, model, stochastic processing time, line efficiency
  • H. Mokhtari, A. Salmasnia Page 424
    The Weibull distribution is widely employed in several areas of engineering because it is an extremely flexible distribution with different shapes. Moreover, it can include characteristics of several other distributions. However, successful usage of Weibull distribution depends on estimation accuracy for three parameters of scale, shape and location. This issue shifts the attentions to the requirement for effective methods of Weibull parameters estimation. It is a known fact that the estimation procedure is inherently a very complicated procedure when the three-parameter Weibull distribution is of interest. Hence, this study suggests a computational approach, greedy randomized adaptive search procedures, with several neighborhood local searches to enhance the quality of estimations. Computational experiments are also implemented to assess the quality of estimations as opposed to benchmark grid search algorithm.
    Keywords: Statistical Inference, Weibull Distribution, GRASP, Grid Search
  • M. Tahari, F. Naeimi Page 432
    In this study, the effect of surface morphologies on the isothermal oxidation behavior of MCrAlY coatings fabricated by high-velocity oxyfuel (HVOF) processes was investigated. To do so, free standing coatings with as-sprayed and polished surfaces were isothermally oxidized at 1050°C. The thickness of the bond coat was approximately 380μm. The Ra of the as-sprayed and polished surfaces were 6.4μm and 1.1μm, respectively. Before and after oxidation, the surface scale composition and morphology were analyzed by scanning electron microscope (SEM/EDX) and X-ray diffraction. The results show that the roughness of the bond coat significantly affected oxide scales formed on the as-sprayed and polished coatings after 100h oxidation. With increasing roughness (Ra) of the bond coat, the oxidation rate constantly increased and composition of thermal growth oxidation (TGO) changed into oxide mixture consisting of Cr2O3, NiO and spinel. In addition, Scanning Electron Microscope analysis showed that thickness of TGO Layer of the polished CONiCrAlY coating at 1050°C was much thinner than that of the as-sprayed one.
    Keywords: Thermal barrier coatings (TBCs), Thermally grown oxide (TGO), Surface roughness, HVOF
  • M. Jamal-Omidi, M. R. Mohammadi Suki Page 439
    In the present paper, a numerical study is performed to investigate the response of different plates aluminum alloys subjected to low velocity impact condition. In this regard, the square AA5083-H116 aluminum plates with dimensions 300×300 and 3 mm and 5 mm thick under low velocity impact are modelled, and a mesh convergence study is carried out to decide the appropriate number of elements. In this research, the influence of strain rate effects[ah1] in low velocity impact response is examined by doing a comparative study using the isotropic elasto-plasticity and the Johnson-cook material models. The response to impact events of models including deflection history and maximum and permanent deflection is extracted and validated by available numerical and experimental data in literature. The results indicate that the strain rate has a significant influence on time histories and increases the accuracy of the predicted data. Then, using the developed modeling procedure, the behavior of three aluminum alloys under low velocity impact is investigated based on Johnson-Cook model. The results show that 7075-T6 and 6061-T6 alloys have the highest and lowest stiffness, respectively. Also, the lowest rate of absorbed energy to mass is observed in the 7075-T6 alloy.
    Keywords: low velocity impact, finite element modeling, Aluminum plate, Johnson, Cook model, strain rate effects
  • M. Eftekhari Page 448
    In this paper, the effectiveness of stiffness and damping of bearing is investigated on the natural frequencies of the rotor-bearing system. The rotor-bearing system consists of a shaft, two bearings and a disk between two bearings. Parallel spring-damper in horizental and vertical directions is considered for modeling the stiffness and damping of bearings. The gyroscopic effect is also considered in derivation of equations, together with its dependence on speed. Numerical results contain the critical speed of shaft for various values of bearing stiffness and damping. Moreover, the first six natural frequencies of rotor are presented in Campbell diagrams.
    Keywords: rotor, bearing system, bearing stiffness, bearing damping, campbell diagram.