Surface Pressure Contour Prediction Using a GRNN Algorithm
Saeid
Attarian
Mechanical and Aerospace Engineering, Azad University, Science and Research Branch
author
M. R.
Soltani
AerospaceEng., Sharif Univ. of Tech.
author
Ali
Davari
, Azad University, Science and Research Branch
author
text
article
2014
eng
A new approach based on a Generalized Regression Neural Network (GRNN) has been proposed to predict the planform surface pressure field on a wing-tail combination in low subsonic flow. Extensive wind tunnel results were used for training the network and verification of the values predicted by this approach. GRNN has been trained by the aforementioned experimental data and subsequently was used as a prediction tool to determine the surface pressure. Most of the previous applications of the GRNN in prediction problems were restricted to single or limited outputs, while in the present method the entire planform surface pressure was predicted at once. This highly decreases the calculation time while preserving a remarkable degree of accuracy. The wind tunnel results verify the accuracy of the data offered by the GRNN, which indicates that the present prediction and optimization tool provides sufficient accuracy with modest amount of experimental data.
International Journal of Engineering
Materials and Energy Research Center
1025-2495
27
v.
6
no.
2014
819
828
https://www.ije.ir/article_72315_9447bc4f0e156ae79192bed1c193bcb2.pdf
Material Flow in Rotary Drums
Mohammad Reza
Yousefi
, Iran Univ. Sci. Tech.
author
Mansour
Shirvani
Chem. Eng., Iran Univ. Sci. Tech.
author
text
article
2014
eng
The experimental investigation of material flow in rotary drums is studied. An equipment in the size of pilot-scale was used to collect experimental data for investigation of validity of the conventional steady-state model of material flow in rotary drums. Also, the transient data of the time required for material movement in the empty drum up to any specified cross section are also reported. The novelty of the work is that fine particles, in place of granular materials, were used in all of the experiments. The investigations reveals of the weak validity of the model for describing the bed depth of material at feeding zone as well as discharge zone. But, it is acceptable at mid zone.
International Journal of Engineering
Materials and Energy Research Center
1025-2495
27
v.
6
no.
2014
829
838
https://www.ije.ir/article_72316_777194624f4f1c95fac4b06f271acf1b.pdf
Adsorption of Malachite Green from Aqueous Solution using Activated Ntezi Clay: Optimization, Isotherm and Kinetic Studies
Regina
Ajemba
Chemical Engineering, Nnamdi Azikiwe University, Awka, Nigeria
author
text
article
2014
eng
The adsorption of malachite green from aqueous solution using a local low cost adsorbent, acid activated Ntezi clay, was investigated. The low cost adsorbent was activated with different concentrations of sulphuric acid and the physicochemical properties of the adsorbent were determined and the structural properties were analyzed using XRF and XRD. The adsorption process was studied as a function of different process parameters such as temperature, adsorbent dosage, contact time, particle size and stirring speed. These process parameters were optimized using response surface methodology (RSM). The significance of the different process parameters and their combined effect on the adsorption efficiency has been established through a full factorial central composite design. The equilibrium modeling was analyzed using Langmuir, Freundlich, Dubini-Radushkevich and Temkin isotherm equation and the results of the experimental data follows the Langmuir adsorption isotherm. Adsorption kinetics follows the pseudo-second order with intra-particle diffusion as the rate-determining step. This investigation has shown that local clay mineral can be modified and used as a good adsorbent in the removal of impurities from contaminated water.
International Journal of Engineering
Materials and Energy Research Center
1025-2495
27
v.
6
no.
2014
839
854
https://www.ije.ir/article_72317_089fb829a676bd55e856d3b59e3efd40.pdf
A Wavelet Support Vector Machine Combination Model for Daily Suspended Sediment Forecasting
M
SadeghpourHaji
Department of Environmental Engineering, Environment and Energy, Science and Research Branc
author
S. A.
Mirbagheri
Department of Civil and Environmental Engineering, K. N. Toosi University of Technology, Tehran, Iran
author
A. H.
Javid
Islamic Azad university Tehran Science and Research Branch, Faculty of Marine Science and Technology, Tehran, Iran
author
M.
Khezri
Department of Environmental Engineering, Faculty of Environment and Energy, Science and Research Branch, Islamic Azad University, Tehran, Iran
author
G. D.
Najafpour
Biotechnology Research Center, Faculty of Chemical Engineering, BabolNoshirvani University of Technology, Babol, Iran
author
text
article
2014
eng
Abstract In this study, wavelet support vector machine (WSWM) model is proposed for daily suspended sediment (SS) prediction. The WSVM model is achieved by combination of two methods; discrete wavelet analysis and support vector machine (SVM). The developed model was compared with single SVM. Daily discharge (Q) and SS data from Yadkin River at Yadkin College, NC station in the USA were used. In order to evaluate the model, the root mean square error (RMSE), correlation coefficient (R) and coefficient of determination (R2) were used. Results demonstrated that WSVM with RMSE =3294.6, R =0.9211 and R2 =0.838 were more desired than the other model with RMSE =6719.7, R=0.589 and R2=0.327. Comparisons of these models revealed that, mean of error and error standard deviation for WSVM model were about 66% and 50% less than SVM model in test period.
International Journal of Engineering
Materials and Energy Research Center
1025-2495
27
v.
6
no.
2014
855
864
https://www.ije.ir/article_72318_9201ff0202b71fc25055c4c56c28eac9.pdf
Micro-modeling of Masonry Infilled RC Moment Resisting Frames to Investigate Arrangement of Compressive Diagonal Struts
Mohammad Amir
Rahemi
Structural Engineering Research Center, International Institute of Earthquake Engineering
author
A. A.
Tasnimi
Structural Engineering Research Center, International Institute of Earthquake Engineering
author
text
article
2014
eng
Accurate modeling of masonry has been a major concern of the researchers in the past decades. Besides reinforced and unreinforced masonry structures, masonry can be found in frame structures as infill panels which are used as partitions and/or external walls. These elements role as a part of structure and introduce a large degree of nonlinearity into the system. In this study, a micro-modeling procedure is introduced using finite element analysis to model masonry infilled reinforced concrete moment resisting frames (RCMRFs). After calibration using material tests and small masonry assemblage experiments, the model will be used to predict the behavioral parameters and failure mode of this type of structures. It will be shown that the proposed procedure is fairly successful in estimation of the stiffness and strength and can simulate the failure mode of the infilled RCMRFs tested under semi dynamic lateral loading. Finally, the process of formation and arrangement of compressive struts in different stages of lateral loading in the infill wall will be discussed. As a result, it will be concluded that the proposed modeling strategy can be used as a means to better recognize the behavior of such structures and to propose new or precise existing simplified models such as equivalent diagonal strut model.
International Journal of Engineering
Materials and Energy Research Center
1025-2495
27
v.
6
no.
2014
865
880
https://www.ije.ir/article_72319_aa582c774bc82dd15aa1796893dc1d6d.pdf
Discrimination of Power Quality Distorted Signals Based on Time-frequency Analysis and Probabilistic Neural Network
Asghar
Akbari Foroud
Electerical & Computer Engineeing, Semnan University
author
mehdi
hajian
Electrical Engineering, Semnan University
author
text
article
2014
eng
Recognition and classification of Power Quality Distorted Signals (PQDSs) in power systems is an essential duty. One of the noteworthy issues in Power Quality Analysis (PQA) is identification of distorted signals using an efficient scheme. This paper recommends a Time–Frequency Analysis (TFA), for extracting features, so-called "hybrid approach", using incorporation of Multi Resolution Analysis (MRA) and Generalized S Transform (GST). Moreover, the proposed scheme is noticed to quality of features and ranking them in order to find the best combination with lower dimension. A new efficient feature ranking method namely Orthogonal Forward Selection (OFS) is applied for selection of the best subset features. Probabilistic Neural Network (PNN) as classifier is considered. An extensive series of simple and complex PQDSs are simulated to verify of suggested detection scheme. Also, sensitivity of the proposed method under different conditions of noise has been investigated. The obtained outcomes are compared with those obtained using other methods in previous research to assess the performance.
International Journal of Engineering
Materials and Energy Research Center
1025-2495
27
v.
6
no.
2014
881
888
https://www.ije.ir/article_72320_038d9ff331373e68581db23ad6979569.pdf
An Intelligent Algorithm based Controller for Multiple Output DC-DC Converters with Voltage Mode Weighting Factor
Saeed
Abedi
Electrical Engineering, Imam Khomeni International University
author
text
article
2014
eng
Multiple output DC-DC converters are widely used in many applications such as aerospace, industrial and medical equipments. The purpose of this paper is to present an intelligent control system for the multiple output DC-DC converters. In order to perform this purpose, a double ended forward DC-DC converter with three output voltages (+5 V/ 50W, +15 V/ 45W and -15 V/ 15W) is considered and analyzed. The voltage mode weighting factor control system with Genetic Algorithm (GA) is performed on the considered DC-DC converter. Furthermore, a PID controller is utilized to minimize the total steady state error. The stability proofs of the system in presence of PID Controller have been analyzed. The results show that the GA weighting factors estimator improves the cross and output regulations in multiple output DC-DC converters. Simulation results verify and confirm the truth and accuracy of the proposed method
International Journal of Engineering
Materials and Energy Research Center
1025-2495
27
v.
6
no.
2014
889
898
https://www.ije.ir/article_72321_58bc03c4aebdca49755a406ab30e492a.pdf
Appling Metaheuristic Algorithms on a Two Stage Hybrid Flowshop Scheduling Problem with Serial Batching (RESEARCH NOTE)
Esmaeel
Ghafari
Industral Engineering, Shahed University
author
text
article
2014
eng
In this paper the problem of serial batch scheduling in a two-stage hybrid flow shop environment with minimizing Makesapn is investigated. In serial batching it is assumed that jobs in a batch are processed serially, and their completion time is defined to be equal to the finishing time of the last job in the batch. The analysis and implementation of the prohibited transference of jobs among the machines of stage one in serial batch is the main contribution of this research. Machine set-up and released time for all jobs are assumed to be zero and no Preemption is allowed. Machines may not breakdown but at times they may be idle. As the problem is NP-hard, a simulated annealing (SA) is developed to give near optimal solutions. Since this problem has also not been studied previously, therefore, a lower bound is developed for evaluating the performance of the proposed SA. Many test problems have been solved using SA and results compared with lower bound. Results showed SA can provide a good near optimal solution for small, median and large size problems in reasonable time.
International Journal of Engineering
Materials and Energy Research Center
1025-2495
27
v.
6
no.
2014
899
910
https://www.ije.ir/article_72322_259815cf15d2721b37d20ed50850d8c3.pdf
A Node-based Mathematical Model towards the Location Routing Problem with Intermediate Replenishment Facilities under Capacity Constraint
Hossein
Karimi
Industrial Engineering, University of Bojnord
author
Soheil
Jalili
Industrial Engineering, K. N. Toosi University of Technology
author
Mostafa
Setak
, K. N. Toosi University of Technology
author
text
article
2014
eng
In this paper, we study the location routing problem with replenishment facilities (LRPRF), an extension of the location routing problem (LRP) where the vehicles can replenish at some replenishment facilities. Vehicles leave the depot with load on-board, serve customers until out of load, and then either return to a replenishment facility to reload or return to the depot, completing their route. For this problem, we initiate a mathematical node-based mixed integer programming model. The objective of the problem is to find routes for vehicles to serve all the customers at a minimal cost in terms of number of routes (vehicles) and total travel cost, without violating the capacity constraint of the vehicles. The solution to the LRPRF is obtained through commercial software GAMS 23.5.1 and Genetic Algorithm (GA) in this paper. Computational results are obtained on a set of randomly generated instances and indicate the effectiveness of the proposed algorithm.
International Journal of Engineering
Materials and Energy Research Center
1025-2495
27
v.
6
no.
2014
911
920
https://www.ije.ir/article_72323_7d5f94f78a8c7b124db196b795106d1c.pdf
Improving the Performance of Bayesian Estimation Methods in Estimations of Shift Point and Comparison with MLE Approach
Batul
Rasti
author
text
article
2014
eng
A Bayesian analysis is used to detect a change-point in a sequence of independent random variables from exponential distributions. In This paper, we try to estimate change point which occurs in any sequence of independent exponential observations. The Bayes estimators are derived for change point, the rate of exponential distribution before shift and the rate of exponential distribution after shift. Likelihood, Prior, Posterior and Marginal distribution of the change point is derived. Also maximum likelihood estimation method is used for determining change point. The sensitivity analysis of Bayes estimators are performed by simulation. Also we suggested a new approach to achieve more precise results by determining correct choice for parameters of prior distribution and compared new approach with existing methods. The result of simulation shows good performance of proposed approach in comparison with existing methods
International Journal of Engineering
Materials and Energy Research Center
1025-2495
27
v.
6
no.
2014
921
932
https://www.ije.ir/article_72324_a3d5bfe433cee433c331e739b4c1dc34.pdf
Preparation of Porous and Dense Bulk Samples in Calcium Magnesium Silicate Systems using Steel Slag and Different Additive by Conventional Sintering Method (TECHNICAL NOTE)
aida
faeghinia
Ceramic Department, Material and Energy Research C, Material and Energy Research Center(MERC)
author
text
article
2014
eng
In order to obtain the bulk brick like samples, the mixture of steel slag, and sintering aid additive (like dolomite, glass, perlite, borax and phosphate sodium) were sintered at 1100°C for 2 minute. The flat and bloated surface appearances were obtained. The bulk densities of final sintered composites were from 1.3 to 2.41 g/cm3 and total porosities were from 15 to 40%. The bending strengths varied from 5.5 to 15.9 Mpa.
International Journal of Engineering
Materials and Energy Research Center
1025-2495
27
v.
6
no.
2014
933
938
https://www.ije.ir/article_72325_dc9155ab440e82fd0dfa0c708821b34b.pdf
Electrodeposition of Nano Hydroxyapatite Coating on Biodegradable Mg-Zn Scaffold (TECHNICAL NOTE)
zahra sadat
seyedraoufi
School of Materials and Metallurgy, Iran University of Science and Technology (IUST)
author
text
article
2014
eng
Magnesium has been recently recognized as a biodegradation metal for bone substitute application. In the present work, porous magnesium-zinc scaffolds were prepared by powder metallurgical process and nano hydroxyapatite (HAP) coating on the Mg-3Zn (wt.%) scaffold was prepared by pulse electrodeposition and alkali treatment processes to improve the corrosion resistance of scaffold. The results indicated the as-deposited coating consists of HAP, DCPD and OCP with needle-like and plate-like structures and the post-treated coating was composed of needle-like particles of nano HAP that developed almost perpendicularly to the substrate. Electrochemical tests showed that the corrosion potential of scaffold significantly increased from –1.475 to –1.365 V and the corrosion current density reduced 1.5-fold in comparison to the scaffold modified by nano hydroxyapatite coating.
International Journal of Engineering
Materials and Energy Research Center
1025-2495
27
v.
6
no.
2014
939
944
https://www.ije.ir/article_72326_ad3e16bc5983bfede24b5cf154456ef2.pdf
Ballistic Performance of Hybrid Armor with Ceramic Inserts and Polymeric Matrix for Different Threat Levels (TECHNICAL NOTE)
Seyed mohammad
Zahraee
Materials, Iranian Research Organization for Science and Tech
author
Ali Reza
Sabet
Composite Materials, Iran Polymer and Petrochemical Institute
author
text
article
2014
eng
Ceramic materials due to their high compressive strength and hardness have been one of prime candidates in armor design in particular when high level threads (impact velocity above 600m/s) are involved. The aim of this work is to investigate ballistic impact resistance potential for a target plate with novel ceramic inserts as against ceramic tiles. Two size 98% alumina (AL2O3) base ceramic inserts with 10mm diameter and 6 and 10mm in length were used in the specimen’s preparation. Also 6 and 10mm thick ceramic tiles were used to compare the ballistic performance. Gas gun was used to carry out high velocity ballistic impact tests in velocity range of 530- 830m/s on both target plates. Results showed outstanding ballistic performance by the target plate with ceramic inserts in term of lower residual velocity for the specimens which experienced perforation and lower damage area compared to totally disintegrated plates containing ceramic tiles. Also specimens containing ceramic inserts showed good ballistic resistance in case of multiple impacts whereas the specimens with ceramic tiles almost totally lost its ballistic potentials. Ability to repair on site (debris removal and new ceramic insert replacement) is among unique advantages of this novel design in the armor application.
International Journal of Engineering
Materials and Energy Research Center
1025-2495
27
v.
6
no.
2014
945
950
https://www.ije.ir/article_72327_cac47c9532f0d43ed8db21e7d46519aa.pdf
A Size-dependent Bernoulli-Euler Beam Formulation based on a New Model of Couple Stress Theory
A.H.
Abolghasemi
Mechanial Eng, Babol University of Technology
author
text
article
2014
eng
In this paper, a size-dependent formulation for the Bernoulli-Euler beam is developed based on a new model of couple stress theory presented by Hadjesfandiari and Dargush. The constitutive equation obtained in this new model, consists of only one length scale parameter that is capable of capturing the micro-structural size effect in predicting the mechanical behavior of the structure. Having one length scale parameter is claimed to be an advantage of the model in comparison with the classical couple stress theory. The governing equations and boundary conditions of the Bernoulli-Euler beam are developed using the variational formulation and the Hamilton principle. The static bending and free vibration problems of a Bernoulli-Euler beam with various boundary conditions are solved. Numerical results demonstrate that the value of deflection predicted by the new model is lower than that of the classical theory. It is also found that natural frequencies obtained by the present couple stress model are higher than those predicted by the classical theory. The differences between results obtained by the present model and the classical theory become significant as the thickness of the beam gets close to the length scale parameter of the beam material.
International Journal of Engineering
Materials and Energy Research Center
1025-2495
27
v.
6
no.
2014
951
960
https://www.ije.ir/article_72328_2b70ef61b0ba12b60a8b15bfe8760c4e.pdf
Optimal Thermodynamic Design of Turbofan Engines using Multi-objective Genetic Algorithm
M
Khodadadi
Mechanical Engineering, Babol Noshirvani university of Technology
author
Admin
Kazemi
Mechanical Engineering, Babol Noshirvani university of Technology
author
Mofid
Gorji
Mechanical Engineering, Babol Noshirvani university of technology
author
text
article
2014
eng
The aim of this study is to optimize performance functions of turbofan engines considering the off-design model of turbofan engine as well as employing multi-objective genetic algorithm. The design variables including high-pressure compressor pressure ratio, low-pressure compressor pressure ratio, fan pressure ratio and bypass ratio are calculated in such a way that the corresponding functions of specific thrust at take-off, as well as thrust specific fuel consumption, propulsive, thermal, and overall efficiencies while cruising are at their best performance conditions. The optimization is done using the modified NSGA II which is among the best multi-objective genetic algorithm methods. The obtained results of Multi-objective optimization will be a set of vectors among from which the designer may choose one depending on the conditions. The study of off-design model of turbofan engine is the significance of this study which has not been considered in similar studies.
International Journal of Engineering
Materials and Energy Research Center
1025-2495
27
v.
6
no.
2014
961
970
https://www.ije.ir/article_72329_3bbb0a45d41cf4f7e55c8a1efb0bd0e8.pdf
Analytical Analysis of The Dual-phase-lag Heat Transfer Equation in a Finite Slab with Periodic Surface Heat Flux (RESEARCH NOTE)
Hossein
Ahmadikia
Mechanical Engineering, University of Isfahan
author
Hossein
Askarizadeh
Mechanical Engineering, University of Isfahan
author
text
article
2014
eng
This work uses the dual-phase-lag (DPL) model of heat conduction to demonstrate the effect of temperature gradient relaxation time on the result of non-Fourier hyperbolic conduction in a finite slab subjected to a periodic thermal disturbance. DPL model combines the wave features of hyperbolic conduction with a diffusion-like feature of the evidence not captured by the hyperbolic case. For the first time, the analytical solution of DPL model of heat conduction equation is obtained adopting Laplace transform method and inversion theorem. The temperature profiles at the front and rear surfaces of the slab are calculated for various temperature gradient relaxation time. The phase and amplitude difference between the front and the rear surface are calculated numerically as a function of the temperature gradient relaxation time, which are reported previously as a function of the heat flux relaxation time. The results demonstrate that increasing on the temperature gradient relaxation time leads to the lower phase difference and upper amplitude difference between the temperature responses of the front and rear surfaces.
International Journal of Engineering
Materials and Energy Research Center
1025-2495
27
v.
6
no.
2014
971
978
https://www.ije.ir/article_72330_be2e76d5752c61891b84f4b997fd89a0.pdf
Analytic Approach to Free Vibration and Buckling Analysis of Functionally Graded Beams with Edge Cracks using four Engineering Beam Theories
Khalil
Sherafatnia
School of Mechanical Engineering, Sharif University of Technology
author
G. H.
Farrahi
School of Mechanical Engineering, Sharif University of Technology
author
S. Ali
Faghidian
Department of Mechanical and Aerospace Engineering, Science and Research Branch, Islamic Azad University
author
text
article
2014
eng
A complete investigation on the free vibration and stability analysis of beams made of functionally graded materials (FGMs) containing open edge cracks utilizing four beam theories, Euler-Bernoulli, Rayleigh, shear and Timoshenko, is performed in this research. It is assumed that the material properties vary along the beam thickness exponentially and the cracked beam is modeled as two segments connected by two mass-less springs (extensional and rotational). Then the equations of motion for the free vibrations and buckling analysis are established and solved analytically for clamped-free boundary conditions. A detailed parametric study is performed to examine the influences of the location and depth of the crack, material properties and slenderness ratio of the beam on the free vibration and buckling characteristics of cracked FGM beams for each of the four engineering beam theories.
International Journal of Engineering
Materials and Energy Research Center
1025-2495
27
v.
6
no.
2014
979
990
https://www.ije.ir/article_72331_7a2a66e9081466f403433b77af0a25b0.pdf
A New Comparative Method To Evaluate the Fracture Properties of Laminated Composite
Naghdali
Choupani
Mechanical Engineering Department, Sahand University of Technology
author
Mohammad Hoseein
Heydari
Mechainical Engineering Department, Sahand University of Technology
author
text
article
2014
eng
In this paper a new method to determine the fracture properties and strain energy release rate for Carbon- Polyester composite has been introduced. Fracture characteristics such as critical stress intensity factor and critical strain energy release rate for mode I, mode II and mixed mode loading were determined using Arcan type specimen. 130 layers of carbon fiber polyester woven composite with each of 0.2mm thickness were put on each other. Theoretical studies to determine strain energy release rate were done using three methods: Corrected Beam Theory (CBT), Compliance Calibration Method (CCM), Virtual Crack Closure Technique (VCCT), and results were recorded and were compared with the results from experimental and numerical attempts. Critical loads were recorded with experimental attempts then applied to the finite element software. Results were recorded and compared with each other to determine the best method. Results show that compliance calibration method and virtual crack closure technique determine strain energy release rate value closer to J-integral in comparison with corrected beam theory. Finally, the fracture surfaces were examined by scanning electron microscope to gain insight the failure responses that shows the fracture surface for mode II is rougher than the fracture surface for mode I and mixed mode.
International Journal of Engineering
Materials and Energy Research Center
1025-2495
27
v.
6
no.
2014
991
1004
https://www.ije.ir/article_72332_2c1169883a28b7357b13f20d16c26c96.pdf