فهرست مطالب

International Journal of Engineering
Volume:31 Issue: 3, Mar 2018

  • TRANSACTIONS C: Aspects
  • تاریخ انتشار: 1397/01/19
  • تعداد عناوین: 15
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  • M. Vatandoost, F. Nateghi Pages 394-404
    Precast prestreesed concrete braces are a new method for seismic strength of Concrete Structures which has the following benefits: a) no wet concrete work in construction site b) No bolt or anchorage to the existing frame c) easy to apply d) short construction period e) low construction cost, to evaluate seismic performance of strengthened structure a model consist of existing frame and concrete braces were created using ABAQUS (nonlinear-finite element) software.Comparison existing and strengthened frame showed that braces are effective in lateral drift decreasing.Study concrete compressive strength on seismic behavior of brace showed that when compression strength of brace is lower than existing frame, retrofitting system has low stiffness and wasn’t effective in reducing lateral drift, but in specimen with compressive strength ratio (brace to frame) two times or more, braces showed high strength and stiffness.
    Keywords: Seismic Retrofitting, Seismic Strength, Concrete Braces, Precast Concrete, Prestressed Concrete, Reinforced Concrete Structure
  • J. Hosseini Mola, T. Barforoshi, J. Adabi Pages 405-414
    Distributed generation (DG) technology is known as an efficient solution for applying in distribution system planning (DSP) problems. Load growth uncertainty associated with distribution network is a significant source of uncertainty which highly affects optimal management of DGs. In order to handle this problem, a novel model is proposed in this paper based on DG solution, considering load uncertainty. This model is designed to minimize network costs including operation and losses. Genetic algorithm is used with the purpose of finding the optimal places, sizes as well as times for DGs. Load uncertainty is also modeled through Markov tree. To illustrate the effectiveness of the proposed model, it is tested in different scenarios considering the effects of the purchased power price, DG penetration factor and DG operation intervals. These scenarios are conducted in two different phases, with and without uncertainty and the results are then compared and discussed. Moreover, by considering load uncertainty in planning, planning models would be robust against network future load variations.
    Keywords: Distributed Generation (DG), Distribution System Planning (DSP), Load Growth, Genetic Algorithm, Markov Tree, Uncertainty
  • S. Zoka, M. Gholami Pages 415-421

    Quantum dot cellular automata (QCA) introduces a pioneer technology in nano scale computer architectures. Employing this technology is one of the solutions to decrease the size of circuits and reducing power dissipation. In this paper, two new optimized FlipFlops with reset input are proposed in quantum dot cellular automata technology. In addition, comparison with related works is performed.The reset pin in the proposed circuits is level triggered. Simulation results demonstrate that the both proposed desgins have efficient structures in terms of area, delay and complexity. The proposed structures are simulated using the QCADesigner and the validity of them has been proved. Simulations of the first proposed level triggered reset D-Flip Flop show that this circuit has 82 quantum cells and needs only two clock cycle for valid operation. In addition the second proposed architecture for level triggered reset D-Flip Flop has only 85 quantum cells and it needs only one clock cycle for proper operation.

    Keywords: Quantum cellular automata, D flip, flop, level triggered, QCADesigner, Clocking zones
  • Y. Yahia Mehrjerdi, A. Yazdekhasti Pages 422-431
    In recent decades, high profits of extended warranty have caused that third-party firms consider it as a lucrative after-sales service. However, customers division in terms of risk aversion and effect of offering extended warranty on manufacturers’ basic warranty should be investigated through adjusting such services. Since risk-averse customers welcome extended warranty, while the customers without taking on risk may remain at the level of basic warranty. In this paper, a multi-objective integer nonlinear programming model is presented for integrating the supply chain of after-sales services. In the suggested model, firstly strategies used by the manufacturers in the basic warranty period and the third party’s policy during the extended warranty period, including the development of a new imperfect maintenance approach, are regulated. Then, the effects of these strategies on the desirability of customers with different levels of risk-taking are analyzed. To optimize the model, the scatter search based approach was introduced for extracting set of non-dominated solutions. The results indicated that increasing level of customers’ risk-taking convinces manufacturers to diminish the basic warranty period and the third party can apply less costly preventive maintenance. Key Words: Warranty, Extended warranty, After-sales services, Customers’ risk-taking, Pareto-set solutions, Multi-objective scatter search
    Keywords: Warranty, Extended warranty, After, sales services, Customer's risk, taking, Pareto, set solutions, Multi, objective scatter search
  • R. Jamshidi Pages 432-439
  • Mahmood Hameed Mahmood H. Mahmood, S. Suryanto, Muataz Hazza Faizi. Al Hazza, Farag I. Haider Pages 440-446
    Copper alloys are widely used in the manufacturing of heat transfer applications, this due to their excellent heat transfer properties. Copper contamination is one of the serious industrial problems in the boiler feed water system. This contamination commonly resulted from copper corrosion reactions in boiler feed water environment. The best way to reduce the copper contamination is by improving copper corrosion resistance. This research studies the developing of copper corrosion resistant by using anodization technique. The anodization experiments are conducted in oxalate solutions of concentrations from 0.1 to 0.5 M, at a temperature range from 24 to 0 ο C and applied potential from 7.5 to 9 V. Anodized coating analyzed using Field emission scanning microscope, energy dispersive X-ray spectroscopy, and X-ray diffraction. Characterization results referred to the formation of copper oxide anodized coating with grain size range from 25 to 68 nm. The corrosion resistance of the anodized copper samples carried out in simulated boiler feed water. Results show that the corrosion resistance of the anodized samples was enhanced. The corrosion protection efficiencies for the anodized coating increased 86.2% and 74.5% in testing solutions contains 3.5% NaCl, and 2 mg/l NH3, respectively.
    Keywords: Copper corrosion, Copper oxide, Anodization technique, Corrosion protection
  • S. Safarian, M. Tahani Pages 454-461
    In this paper, an atomistic based finite element model is developed to investigate the influence of topological defects on mechanical properties of graphene. The general in-plane stiffness matrix of the hexagonal network structure of graphene is found. Effective elastic modulus of a carbon ring is determined from the equivalence of molecular potential energy related to stretch and angular deformation. A hexagonal carbon ring as a unit cell of graphene sheets is modeled by four-node elements and by applying three-node triangular elements, Stone-Wales (SW) defect as an important topological defect which leads to the formation of two heptagons and pentagons is modeled. In this method, both pristine structure of graphene and graphene with SW defect are considered and to get more real structure, an atomistic model of a small part of graphite sheet around the defect site, is modeled in Gaussian software and new arrangement around SW defect are obtained by minimizing its energy. Young’s modulus, shear modulus and Poisson’s ratio of the pristine single-layered graphene sheet (SLGS) and the effect of topological defects on the elastic properties of SLGS is examined. The numerical results from this new model show good agreement with data available in the literature.
    Keywords: Graphene sheet, Defects, Atomistic model, Finite element method, Elastic properties
  • M. Musabbikhah, H. Saptoadi, S. Subarmono, M. Arif Wibisono Pages 462-470
    The main purpose of this work is to optimize the biomass drying and carbonization process in terms of both proximate analysis and biomass calorific value, simultaneously. The biomass material used in the study is coconut shells. The independent variables are the drying temperature, the drying time, the carbonization temperature and the carbonization holding time. The dependent variables are proximate analysis and calorific value. The primary methods used to gain the expected result are Taguchi and multi-response signal-to-noise (MRSN) procedure. Simultaneous optimization by using MRSN generate a value of 2.48 and the result corresponds to a drying temperature of 100 °C, a drying time of 24 h, carbonization temperature of 650 °C, and carbonization time of 120 mins. These results are best achieved by using configuration A1B3C3D3. The optimal expected values obtained in this study are maximum calorific values and fixed carbon of 7744 cal/g and 92.934%, respectively, and minimum moisture, volatile matter, and ash content of 0.354%, 2.318%, and 1.437%, respectively. All indicators are satisfied since the resulting model is deemed to be valid and feasible. The novelty of this work is the simultaneous parameter optimization of the five response variables, which have different quality characteristics into a single best parameter.
    Keywords: carbonization, drying, coconut shell, multiple regression, Taguchi, MRSN
  • K. Aliakbari, N. Safarzadeh, S. S. Mortazavi Pages 479-485
    The main purpose of this study is to review the cause for the crankshaft failure of six-cylinder diesel engine of a wheel loader after passing a short period of time. The failure had occurred after 4800 hours of in-service in the fifth crankpin of the crankshaft. Hardness and tensile tests were carried out to study their mechanical properties. Spectrophotometer machine was used to examine the chemical composition of the crankshaft material. To examine the material microstructure, its defects and the morphology of fracture surface, optical microscopes (OM) and scanning electronic microscopes (SEM) equipped with energy dispersive spectrometry (EDS) were used. The morphology of fracture surface showed that the fracture is of the smooth type and has occurred due to the fatigue. Main origin of the fatigue cracks appeared on the surface of the crankpin might be created by the existence of oil impurities, the impurities on the surface of the crankpin, inappropriate machining on the surface of the crankpin or severe wear and pitting from insufficient lubricating.
    Keywords: Automotive engineering, Wheel loader, Crankshaft failure, Fatigue crack, Failure cause
  • M. H. Sangdani, A. Tavakolpour-Saleh Pages 480-486

    In this paper, the uncertain dynamic parameters of an experimental target tracker robot are identified through the application of genetic algorithm. The considered serial robot is a two-degree-of-freedom dynamic system with two revolute joints in which damping coefficients and inertia terms are uncertain. First, dynamic equations governing the robot system are extracted and then, simulated numerically. Next, an open-loop experiment with finite duration step inputs is implemented on the experimental setup to collect practical output data. Accordingly, a desired objective function is defined as the sum of discrepancy between the experimental and simulated output data. Subsequently, a genetic algorithm is employed to explore the best damping coefficients and inertia terms of the simulation scheme so as to minimize the presented cost function and taking into account the same input data for both simulation and experiment. Finally, the simulated output data based on the identified robot parameters reveal an acceptable agreement with the measured outputs through which validity of the identification scheme is affirmed.

    Keywords: Parameter identification, target tracker robot, genetic algorithm
  • S. Rahimi, Z. Baniamerian, S. Mazdak, E. Sharifi Tashnizi Pages 487-494

    Plastic injection is a method in which, with using an extruder in granules, plastic is injected in a hole with high pressure. Because of meeting the two flow fronts in this process welding line will be made. Along the welding line the strength of produced part is low; therefore the position of welding line and its clarity are very important. In this paper, analyzes have been done with Fluent and Mold Flow softwares. In addition, verification of these analyzes have been done with practical experiments in order to study the effect of injection pressure and temperature on the welding line and its clarity. The materials used in these experiments are ABS and PP. Results show that applying different injection pressure and temperatures affects the strength of the produced part.

    Keywords: Injection molding, Injection pressure, Injection temperature, Tensile test, Weld line
  • R. Sadeghi Rad, N. Nahavandi, Ali Hosseinzadeh, S.H. Zegordi Pages 494-501
    In this paper, a mathematical programming model is presented for integrated problem of closed loop supply chain network design and supplier selection. The suppliers propose discount policy based on purchase amount and loyalty of buyers which are both taken from the elements of RFM (Recency, Frequency and Monetary) technique. The main objective of this paper which is formulated by a mixed-integer programming model is to minimize the total cost through determining location of facilities, production plan, inventory levels, flows between facilities, transportation type, purchasing amount and selecting best supplier based on a beneficial relationship. Sensitivity analysis is carried out to validate the model and examine the effects of considering discount according to purchase amount and loyalty on the supply chains costs and decisions. Computational results show the effectiveness and usefulness of the model.
    Keywords: Supplier selection, Closed, loop Supply Chain Network, Loyalty, Discount
  • R. Nazemnezhad Pages 495-503

    In this paper surface energy and elastic medium effects on torsional vibrational behavior of nanorods are studied. The surface elasticity theory is used to consider the surface energy effects and the elastic medium is modeled as torsional springs attached to the nanorod. At the next step, Hamilton’s principle is utilized to derive governing equations and boundary conditions. Then, with the aid of an analytical method, natural frequencies are obtained and effects of various parameters on torsional frequencies are studied in details. It is concluded from the present study that the surface energy can make nanorods unstable depending on the nanorod dimension and frequency number. Results of the present study can be useful in design of nanoelectromechanical systems like drive shafts.

    Keywords: Surface energy, Elastic medium, Torsional vibration, Nanorod, Natural frequency
  • R. Hasanzadeh, T. Azdast Pages 504-510

    Polyamide 6 (PA6) is used in many applications due to its advantages and improving its properties seems essential. For this purpose in the present study, PA6 was melt compounded with various multi-walled carbon nanotubes (MWCNTs) contents and then was foamed using Azodi carbon amide (ACA) as blowing agent under different injection molding conditions. Morphological properties were investigated using X-ray diffraction (XRD) and scanning electron microscopy (SEM) tests. The results demonstrated that an appropriate distribution of MWCNTs was observed in polymeric matrix and 0.85, 0.94 and 1 Å increase in distance between walls of CNTs was observed. Also, the SEM results illustrated that microcellular structure was achieved in all samples. The results illuminated that mean cell size was improved about 34% in samples containing 1 wt% MWCNT. The tensile properties of samples were investigated and the effect of MWCNTs content was studied on specific tensile and yield strengths. The results indicated that specific tensile strength and yield strength were significantly increased almost 164% and 147% by addition of 1 wt% of MWCNTs, respectively.

    Keywords: Foam, Mechanical properties, Nanocomposite, Polymer, XRD
  • A. Lekomtsev, K. Vyatkin, D. Martyushev Pages 511-515

    On the basis of key ways of oily waste treatment in Russia which has been described in the article and on the example of oil-contaminated soil (OCS) treatment there can be considered two most widespread technologies: bioremediation and thermal recovery. We developed the process flow sheet of the equipment (UT-2S) for industrial oily wastes treatment on the basis of high temperature air tight decomposition of oily waste. We have also worked out criteria of prime cost, OCS treatment period as well as OCS purification efficiency and industrial emission of harmful substances of each technology of oily waste treatment with the aim of its comparison. The analysis of the results received during this work makes possible to find out advantages and disadvantages of OCS recycling technologies and to evaluate efficiency of each technology.

    Keywords: oily waste, oil, contaminated soil treatment, bioremediation, thermal decomposition of soil