فهرست مطالب

International Journal of Engineering
Volume:29 Issue: 12, Dec 2016

  • TRANSACTIONS C: Aspetcs
  • تاریخ انتشار: 1395/10/14
  • تعداد عناوین: 17
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  • H. Hadiyanto, W. Widayat*, A. Duma Pages 1635-1641
    Since the conventional esterification method requires long processing time and gives low yield, the intensification of this process is still an interesting subject to be investigated. To reduce the oil extraction cost from seeds which accounts for almost 70% of total processing cost, in situ esterification has been recently introduced. The objective of this study was to produce biodiesel from rubber seeds oil through in situ esterification, assisted by ultrasound irradiation at 42 kHz for 30 min. The experiment was carried out in two stages of catalyst additions: H2SO4 (varied from 0.1-1% v/v) and NaOH (0.1%) and the esterification was conducted at 60 oC for 30 min under ultrasound frequency of 42 kHz. The results showed that the optimum yield of fatty acid methyl ester (FAME) was 35% which correspond to yield of biodiesel of 92.5% under conditions of rubber seed ratio to methanol 1:1.75 (w/v), catalyst H2SO4 loading of 1% and catalyst KOH loading of 0.1%.
    Keywords: Biodiesel, Rubber Seeds, In Situ, (Trans)Esterification, Fatty Acid Methyl Ester, Ultrasonic
  • E. Abdollahzadeh Sharghi*, A. Shorgashti, B. Bonakdarpour Pages 1642-1649
    The characterizations of vegetable oil wastewater (VOW) are unpleasant odor, dark color, and high organic contents, including large amounts of oil and grease (O&G), chemical oxygen demand (COD), fatty acids and lipids. Therefore, VOWs should be treated efficiently to avoid the environmental pollution. The aim of the present study was the investigation of VOW biological treatment using membrane bioreactor (MBR) in terms of organic pollutant removal performance and membrane fouling. During 30 days MBR operation at hydraulic retention time and solid retention time of 48 h and 20 days, respectively, there was a consistently low turbidity (
    Keywords: Membrane Bioreactor, Vegetable Oil Wastewater, Biological Treatment, Organic Pollutant Removal, Membrane Fouling
  • M. Moradi, A. A. Zinatizadeh*, S. Zinadini Pages 1650-1658
    The textile industry is a water intensive industry that produces a large amount of highly colored wastewater that must be properly treated before disposal or reuse. In the present study, to verify the possibility of reusing textile wastewater with nanofilteration (NF), an attempt was made to treat synthetic reactive dye aqueous solution by commercial nanofiltration membrane. Experiments were conducted based on a central composite face-centered design and analyzed using response surface methodology. Dye concentration (10-50 mg/l), operating pressure (3–6 bar), and initial pH of the dye solution (3–9) were selected as the operating variables to analyze, optimize and model the process. The results showed that alkaline and acidic conditions led to considerable increase in dye rejection and permeation flux that high quality of water could be recovered. This study clearly showed that response surface methodology was one of the suitable methods to optimize the operating conditions and maximize the dye removal. Also, the commercial NF membranes could be efficiently applied in the dye removal process in a one-stage process.
    Keywords: Dye Removal, Textile Wastewater, Direct Red 16, Nanofiltration Membrane, RSM
  • M. Tanzifi*, K. Karimipour, M. Najafifard, S. Mirchenari Pages 1659-1669
    The present study seeks to investigate the capacity of polyaniline/titanium dioxide (PAn/TiO2) and Polypyrrole/titanium dioxide (PPy/TiO2) nano-adsorbents to adsorb Congo red anionic dye (CR) from aqueous solution. The variables effective in CR adsorption, including adsorbent dose, pH of the solution, contact time, initial dye concentration, and temperature were examined. The study yielded the result that a decrease in pH increases the adsorption capacity of both nano-adsorbents. The adsorbent dose and optimum contact time of PAn/TiO2 and PPy/TiO2 nano-adsorbents were [0.1 gr and 20 min] and [0.2 gr and 60 min], respectively. The adsorption kinetics was studied with the pseudo-first-order, pseudo-second-order, and Weber–Morris equations. Kinetic studies showed that the CR adsorption process onto both nano-adsorbents followed the pseudo-second-order kinetics model, which indicates that the adsorption process is chemisorption-controlled. Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich Isotherms were applied to the adsorption data to estimate the maximum adsorption capacity as well as the intensity and energy of adsorption. The experimental data were best represented by Freundlich isotherm model compared to the other models. Analysis of data with Dubinin-Radushkevich isotherm showed that the adsorption of CR onto both nano-adsorbents is a chemisorption process. Moreover, Thermodynamic parameters such as ΔG, ΔH, and ΔS were calculated. The results showed that the adsorption of CR onto both nano-adsorbents was spontaneous and exothermic.
    Keywords: Polyaniline, Polypyrrole, Titanium Dioxide, Adsorption, Kinetic Studies, Isotherm, Thermodynamic, Congo Red
  • S. A. Shahidi*, A. Ghorbani-Hasansaraei, M. Mohebbi, A. Motamedzadegan Pages 1670-1676
    The effect of frying pressure on the kinetics of color changes during atmospheric and vacuum deep fat frying of Reshteh Khoshkar has been studied. The Hunter color parameters redness, yellowness, lightness and total color difference were used to estimate color changes during frying as a function of process. Lightness (L*) decreased from 85.37 to 75.01 with vacuum frying time, while redness (a*), yellowness (b*) and total color difference increased from -2.09, 4.92 and 0 to 1.22, 37.01 and 31.56, respectively. It was observed that the severity of colour change was higher in atmospheric frying process than the vacuum frying process. The changes in color parameters were modeled by zero-order, first-order and a combined kinetics model. The two first-order and combined kinetics models fitted properly the values of color changes during frying, with good coefficient of determination. The combined model used can describe the experimental colour parameters better than the other studied kinetics models.
    Keywords: Vacuum Frying, Color, Kinetics
  • M. R. Kosari, H. Sepehrian*, R. Salamat Ahangari Pages 1677-1683
    The current study was aimed at uranium (VI) ions adsorption using a anion exchanger resin, Dowex®2x8, in the presence of sulfate anions. Evaluation of operational parameters including contact time, pH, initial concentration of uranium ions, and presence of various anions (including phosphate, sulfate, chloride, fluoride, and nitrate) in the solution was assessed on sorption performance of Dowex 2x8. Employing the Langmuir and Freundlich binding models, isotherm analysis was performed to clarify the relation between uranium ions adsorbed on the resin and the concentration of remaining uranium ions in the aqueous phase. To reveal the rate-limiting step of the sorption process, kinetic modeling using pseudo first-order and pseudo second-order equations was also carried out. Maximum sorption capacity for Dowex 2x8 anionic exchanger resin on uranium removal process was found to be 303.03 mmol g-1. It was also disclosed that existence of diverse anion contents in the solution could affect the uranium sorption using Dowex 2x8 anion exchanger resin.
    Keywords: Dowex 2x8, Anion Exchanger Resin, Anion Effect, Adsorption, Uranium, Heavy Metals
  • S. Asadi Amiri, H. Hassanpour* Pages 1684-1690
    Joint Photographic Experts Group (JPEG) is one of the most widely used image compression methods, but it causes annoying blocking artifacts at low bit-rates. Sparse representation is an efficient technique which can solve many inverse problems in image processing applications such as denoising and deblocking. In this paper, a post-processing method is proposed for reducing JPEG blocking effects via sparse representation. In this method, a dictionary is learned via the single input blocky image using K-SVD. There is no need for any prior knowledge about the blocking artifacts. Experimental results on various images demonstrate that the proposed post-processing method can efficiently alleviate the blocking effects at low bit-rates and outperform some new well-known image deblocking methods.
    Keywords: Image Compression, Blocking Effect, Post, processing, Sparse Representation, Low Bit, rate
  • N. Nahavandi*, M. Abbasian Pages 1691-1706
    Nowadays energy saving is one of the crucial aspects in decisions. One of the approaches in this case is efficient use of resources in the industrial systems. Studies in real manufacturing systems indicating that one or more machines may also act as the Bottleneck Resource/ Resources (BR). On the other hand, according to the Theory of Constraints (TOC), the efficient use of resources in manufacturing systems is limited by the capacity of the BR(s). Hence, in order to improve the performance of such systems, the BR(s) should be identified and assessed and improved using capacity of such resources to the greatest extent possible. Studies indicating that Bottleneck Resource Detection (BRD) problem in the ―Multi-Objective and the Dynamic conditions‖ of job-shop is an important issue which has not been studied so far due to its computational complexity. Hence, the development of an efficient approach to identify and assess BRs in Multi-objective Dynamic Job Shop (MODJS) has been considered as the subject of this paper. In this article, a BRD method based on the Taguchi method for MODJS (TM-MODJS) has been developed. This method takes the objectives of the MODJS as estimated indices and carries out typical and finite number of experiments by combining different suitable dispatching rules to detect BR(s) which have the greatest effect on the estimated index. Comparing the results indicates effectiveness of the developed method especially in scheduling which results in a reasonable time.
    Keywords: Energy Saving, Multi, objective Dynamic Job Shop, Theory of Constraints, Bottleneck Resource, Bottleneck Resource Detection
  • A. Zarei, H. Khademi Zare*, M. Nakhaei Nejad Pages 1707-1716
    Making decisions about the economic selection of the customers plays a significant role in the sale and logistic management of the companies. Furthermore, another issue affecting the relationship between the suppliers and the customers is the proper and timely distribution of the products as well as the optimum mixing of the distribution routes to reduce transportation costs. In this paper, the issues of the integration of routing, and the economic selection of customers has been explored aiming at minimizing the transportation, maintenance, and discount costs and maximizing the products selling profits. In addition, to the amount of customer''s purchasing, costumers'' collection period is effective to offer them discounts. The economic customers are selected due to three factors: the discount on the price of the product, the marginal profit of the requested products, and the distance from the supplier''s warehouse. Games software was used for the exact solution of the model, and Simulated annealing algorithm was used to solve the model in larger dimension. The efficiency and applicability of the proposed model was approved comparing the optimum results with a high preciseness as 98.91 percent. Moreover, in the case study of Kalleh Company, the results revealed 14% increase in pure profits.
    Keywords: Vehicle Routing, Economic Selection of the Customers, Discounts, Collection Period, Optimization, Distribution, Sales Planning
  • E. Ahmadi*, M. H. Abooie, M. Jasemi, Y. Zare Mehrjardi Pages 1717-1725
    In this paper, the nonlinear autoregressive model with exogenous variables as a new neural network is used for timing of the stock markets on the basis of the technical analysis of Japanese Candlestick. In this model, the “nonlinear autoregressive model with exogenous variables” is an analyzer. For a more reliable comparison, here (like the literature) two approaches of Raw-based and Signal-based are devised to generate the input data of the model. The correct predictions percentages for periods of 1- 6 days with the total number of buy and sell signals are considered. The result proves that to some extent the approaches have similar performances while apparently, they are superior to a feed-forward static neural network. The created network is evaluated by the measure of Mean of Squared Error and the proposed model accuracy is calculated to be extremely high.
    Keywords: Finance, Stock Market Forecasting, Technical Analysis, NARX Recurrent Neural Network, Levenberg, marquardt Algorithm
  • M. Mahdavi Jafari, G. R. Khayati* Pages 1726-1733
    In this study, artificial neural network was used to predict the microhardness of Al2024-multiwall carbon nanotube(MWCNT) composite prepared by mechanical alloying. Accordingly, the operational condition, i.e., the amount of reinforcement, ball to powder weight ratio, compaction pressure, milling time, time and temperature of sintering, as well as vial speed were selected as independent input and the mean micro-hardness of composites was selected as model output. To train the model, a Multilayer perceptron neural network structure and feed-forward back propagation algorithm has been employed. After testing many different ANN architectures, an optimal structure of the model i.e. 7-25-1 was obtained. The predicted results, with a correlation relation between 0.982 and 0.9952 and 3.26% mean absolute error, show a very good agreement with the experimental values. Furthermore, the ANN model was subjected to a sensitivity analysis and the significant inputs affecting hardness of the samples were determined.
    Keywords: Al2024 Multiwall Carbon Nanotube Composite, Artificial Neural Network, Microhardness, Mechanical Alloying
  • S. Hosseini Hashemi, H. Bakhshi Khaniki*, H. Bakhshi Khaniki Pages 1734-1740
    In this article, nonuniformity effects on free vibration analysis of functionally graded beams is discussed. Variation in material properties is modeled after power law and exponential models and the nonuniformity is assumed to be exponentially varying in the width along the beams with constant thickness. Analytical solution is achieved for free vibration with simply supported conditions. Results show that functionally graded material (FGM) accompanying section variation have a significant effect on natural frequencies of FGM nonuniform beams. In order to show this dependency, Al/Al2O3 composite beam is modeled and the first three natural frequencies with simply supported boundary conditions is obtained for different power law and exponential parameters which shows a great sensitivity to nonuniformity in different shape modes.
    Keywords: Free Vibration, Analytical Solution, Al, Al2O3 Composites, Functionally Graded Materials, Variable Cross Section Beam
  • M. Najimi, F. Haji Aboutalebi*, H. Beheshti Pages 1741-1746
    In this paper, the plates made of functionally graded material (FGM) with and without a crack are numerically simulated, employing the finite element method (FEM). The material property variations are defined to be fully continuous; therefore, the elements can be as small as required. For this purpose, variations of the material properties are applied in both the integration points and in the nodes by implementing a subroutine in the ABAQUS software and hence, the stress field in the singular points such as crack tip is accurately achieved. First, the stresses in the plate without a crack are numerically determined and the accuracy of FGM behavior is validated. Then, the J-integral is investigated and the stress intensity factor (SIF) of the plate with a crack is calculated, using the strain energy release rate (SERR) and the J -integral. In the following, dependency of the J-integral on the path is studied and the results are compared with the contour independent J-integral. Finally, it is shown that if the selected path limits toward zero, the results of the J-integral, the SERR, and the contour independent J-integral are all the same. This is due to considering the continuously varying of material properties and the effect of fining the mesh at the crack tip.
    Keywords: J, Integral, Stress Intensity Factor, Functionally Graded Material, Strain Energy Release Rate
  • G. Majzoobi*, S. Moradi Pages 1747-1756
    The ballistic response of the high strength, low alloy (HSLA-100) steel at ambient and temperatures of -400, -800 and -1960°C is investigated in this work. Lambert-jonas equation is used to fit the experimental results into a curve. The effect of quenching on ballistic behavior of HSLA 100 is also studied. The experiments are conducted on 3mm thick rectangular specimens impacted by blunt tip projectiles. The results indicate that for the as-received material, the ballistic limit is nearly the same for ambient and -400°C temperatures, but increases significantly by 30% and 40% for 800 and - 1960°C temperatures, respectively. The same trend is observed for the quenched specimens. However, the increase of ballistic limit is lower for the quenched specimens and is 16% and 30% for -800 and - 1960°C temperatures, respectively. The ballistic test was also simulated using Ls-dyna hydrocode to examine the effect of parameters such as the specimen’s thickness, the projectile’s tip shape and mass on the ballistic limit of the materials.
    Keywords: High Strength, Low Alloy, 100, Ballistic Limit, Sub, zero Temperature, Lambert, Jonas, Residual Velocity
  • M. Delkhosh, M. Saadat Foumani* Pages 1757-1764
    Equivalent consumption minimization strategy (ECMS) is one of the main real-time control strategies for hybrid electric vehicles (HEVs). This paper proposes a method to modify this strategy. This modification reduces calculation time of ECMS and therefore, facilitates its application as the real-time controller. Dynamic programming (DP) method is employed to reach this aim. This method is applied on the considered HEV in different drive cycles and its results are used to reduce the calculation time of the ECMS. It is notable that the objective of DP in the urban cycles is to simultaneously minimize the fuel consumption (FC) and NOx emission, while the objective in the highway cycles is only the vehicle FC. In order to examine the success of the proposed modifications, the modified ECMS is compared with the basic ECMS in different drive cycles. It is demonstrated that the execution time of the modified ECMS is much less than that of basic ECMS, while the vehicle‟s FC and NOx levels slightly increase through application of the modified ECMS.
    Keywords: Hybrid Electric Vehicle, Equivalent Consumption Minimization, Strategy, Real, time, Fuel Consumption, NOx Emission
  • H. Nami*, F. Mohammadkhani, F. Ranjbar Pages 1765-1774
    Thermodynamic analysis of a novel combined system which is combination of methane fired gas turbine cogeneration system (CGAM) with a supercritical CO2 recompression Brayton cycle (SCO2) and an Organic Rankine Cycle (ORC) is reported. Also, a comprehensive parametric study is performed to investigate the effects of some important parameters on the performance of the proposed system. Finally, a thermodynamic optimization is done to maximize energy and exergy efficiencies. The results showed that, the energy and exergy efficiencies are maximized at particular compressor pressure ratios and the values depend on the operating parameters of the system. Energy and exergy efficiencies are determined to be 85.33% and 54.18%, respectively, for the proposed system under the base condition. Moreover, the parametric study showed that in addition to the operating parameters of the system, ambient temperature has also an important effect on the system performance as energy efficiency increases and exergy efficiency decreases with the ambient temperature increment.
    Keywords: Combined Cycle, SCO2, Organic Rankine Cycle, Energy, Exergy, Optimization
  • V. Alimirzaloo*, V. Modanloo, E. Babazadeh Asbagh Pages 1775-1782
    One of the challenges in the printing industry is the presence of extra lines in printing design. This problem is due to the improper surface roughness of carved cylinders. This research endeavors to specify and optimize the effective parameters on the surface roughness of chrome coated printing cylinders in the finishing process that is done using a finish star machine. Investigated parameters include lubricant volume, feed rate of machine head, emery feed rate, emery compressive force, emery vibration and peripheral speed. By performing some experiments designed by response surface methodology, suitable ranges for the parameters were determined using contour plots and desirability function approach. Results show that the head feed rate, peripheral speed of the part and emery force are the significant parameters on the surface roughness. Surface roughness decreases by reducing the head feed rate. By increasing the emery force up to ten kilogram, surface roughness increases but afterwards gradually decreases. The roughness decreases by increasing the peripheral speed of the part up to 40 m/min, but increases after this value. At last, suitable range and optimal value of the effective process parameters was achived for the desirable surface roughness that is between 0.32 to 0.37 micron.
    Keywords: Printing Cylinders, Roughness, Finishing, Response Surface Methodology