@article { author = {Asadi, Sekineh and Hassanpour, Hamid}, title = {Image Quality Enhancement Using Pixel Wise Gamma Correction}, journal = {International Journal of Engineering}, volume = {24}, number = {4}, pages = {301-312}, year = {2011}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {This paper presents a new automatic image enhancement method by modifying the gamma value of its individual pixels. Most of existing gamma correction methods apply a uniform gamma value across the image. Considering the fact that gamma variation for a single image is actually nonlinear, the proposed method locally estimates the gamma values in an image using support vector machine. First, a database of training images are constructed from various standard images under different gamma conditions. Then by windowing each of the training images, a number of features that characterize images content are computed from its pixel intensity histogram, gray level co-occurrence matrix, and discrete cosine transform domain. To improve the gamma values of an image the aforementioned features are initially computed in sliding windows, then SVM is employed to estimate the gamma value in each window. In this study, it is shown that the proposed method has performed well in improving the quality of images. Subjective and objective image quality assessments used in this study attest superiority of the proposed method compared to the existing methods in image quality enhancement using image gamma value.}, keywords = {image enhancement,Gamma Correction,Feature selection,SVM}, url = {https://www.ije.ir/article_71930.html}, eprint = {https://www.ije.ir/article_71930_5128ebf43ab10fc8f9cfc5f3cf747ba5.pdf} } @article { author = {Hosseinzadeh, Naghdali}, title = {Vibration Mechanism of 13th Century Historical Menar-Jonban Monument in Iran}, journal = {International Journal of Engineering}, volume = {24}, number = {4}, pages = {313-324}, year = {2011}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {Abstract    Historical monument of Menar-Jonban (shaking tower) is located in the famous city of Isfahan in central Iran. Initial construction of this interesting and unique masonry monument belongs to 700 years ago. This monument has two vibrating circular towers of 7.5 m height. These towers are separated from each other by a distance of 9.2 m and constructed on top of an ancient tomb of 10 m height. When one of the towers is shaking by the human force, the other one immediately starts to vibrate without transmitting any significant vibration to the other parts of the structure. This unique dynamic behavior has become a puzzle to architects and structural engineers for many years. Visitors from all over the world, climbing to the top of one of the towers and by shaking one, cause automatic shaking of the other tower. In this paper, the description of the structure, free and forced vibration tests setup, test results and findings on this unique structure is presented. Moreover, to identify the dynamic characteristics and behavior of this monument, analytical studies have been performed and the results of the various possible mathematical models were compared with measured response for system identification purposes.}, keywords = {historical monument,Isfahan,Vibration Mechanism,masonry monument,Vibration tests}, url = {https://www.ije.ir/article_71931.html}, eprint = {https://www.ije.ir/article_71931_e3cae4128e8d7954b87eaeeec649554c.pdf} } @article { author = {Yazdani, Azad - and Kowsari, Milad}, title = {STATISTICAL PREDICTION OF THE SEQUENCE OF LARGE EARTHQUAKES IN IRAN}, journal = {International Journal of Engineering}, volume = {24}, number = {4}, pages = {325-336}, year = {2011}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {The use of different probability distributions as described by the Exponential, Pareto, Lognormal, Rayleigh, and Gama probability functions applied to estimation the time of the next great earthquake (Ms≥6.0) in different seismotectonic provinces of Iran. This prediction is based on the information about past earthquake occurrences in the given region and the basic assumption that future seismic activity will follow the pattern of past activity by maximizing the conditional probability of earthquake occurrence. The estimated recurrence times and the error of estimation for different distributions have been computed for different provinces.}, keywords = {Distribution,Earthquake occurrence,Error,Seismotectonic provinces}, url = {https://www.ije.ir/article_71933.html}, eprint = {https://www.ije.ir/article_71933_0b4eeb559abd85a3cc2bddc98feb9055.pdf} } @article { author = {Marandi, Seyed Morteza}, title = {Reducing the Forces Caused by Earthquake on Retaining Walls Using Granulated Rubber-Soil Mixture}, journal = {International Journal of Engineering}, volume = {24}, number = {4}, pages = {337-350}, year = {2011}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {In recent years, various studies have been undertaken on how to use waste materials in civil engineering projects. Among waste materials, waste rubber has been highlighted to be used for different purposes such as reinforcing of soil and making of reinforced slopes. To investigate the properties of granulated rubber-soil mixture and its application in making of slopes behind retaining walls, some series of cyclic triaxial tests and numerical analyses were carried out. In the former, dynamic properties of granulated rubber-soil mixture such as shear modulus and dynamic behavior were obtained and in the latter the effect of using granulated rubber-soil mixture on dynamic pressures and displacement of retaining walls during earthquake was investigated. The results of the present study showed that for all the confining pressures, with an increase in rubber percentage, shear modulus decreases while for any percentage of rubber inclusion, shear modulus increases as the confining pressure increases. In addition, new relations were introduced to define maximum shear modulus (Gmax) and Normalized shear modulus as functions of confining pressure and granulated rubber percentage. Regarding the dynamic analyses of the retaining wall, with an increase in rubber percentage, a decrease in dynamic pressure and residual displacement was observed.Keywords: Retaining walls, dynamic properties, horizontal forces, granular soil, granulated rubber, earthquake.}, keywords = {Retaining Walls,dynamic properties,horizontal forces,Granular soil,granulated rubber,Earthquake}, url = {https://www.ije.ir/article_71935.html}, eprint = {https://www.ije.ir/article_71935_101170e5c4dd3055c0eb588b8708cff0.pdf} } @article { author = {Torabi, M.}, title = {Electrochemical Evaluation of PbO Nanoparticles as Anode for Lithium Ion Batteries (Technical Note)}, journal = {International Journal of Engineering}, volume = {24}, number = {4}, pages = {351-356}, year = {2011}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {PbO nanoparticles were synthesized using hydrothermal process. Scanning electron microscopy (SEM) was used in order to investigate of PbO powders. X-ray diffraction (XRD) pattern confirmed β-PbO formation during this process. The crystallite size of the powders was calculated using Scherrer formula about 74.6 nm. Electrochemical evaluation of the PbO nanoparticles as anode for Li-ion batteries shows that two reactions were occurred during the first discharge. Some intermediates also were seen during Pb alloying with Li. The cyclic loading of the PbO nanoparticles show reversible capacity higher than 125 mAh g-1}, keywords = {anode material,Lead,Oxide,Hydrothermal,Li,ion Batteries}, url = {https://www.ije.ir/article_71937.html}, eprint = {https://www.ije.ir/article_71937_ae3a3a6aad1e740112ed98bd053cec6a.pdf} } @article { author = {Mahshid, S. and Bagheri, N. and Sadrnezhaad, S.K.}, title = {EFFECT OF Si ANTIOXIDANT ON THE RATE OF OXIDATION OF CARBON IN MgO- C REFRACTORY}, journal = {International Journal of Engineering}, volume = {24}, number = {4}, pages = {357-366}, year = {2011}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {Progressive conversion/shrinking core (PC-SC) models of constant-size cylinders were exploited to interpret the decarburization reactions of MgO-C-Si bricks heated up under blown air. Chemical adsorption/solid (or pore) diffusion mechanisms governed the reaction rate. With 5% silicon, chemical adsorption vanished at 1000 and 1100°C. The oxidation rate lowered then with temperature. This was due apparently to the blocking of the pore-end gorges by the voluminous compounds (like Forstrite). Arrhenius plots of the specific rates yielded the activation energies of the prevailing steps. Without Si antioxidant, three steps were appreciated having activation energies of 51.65 (for chemical adsorption), 125.75 (for solid-phase diffusion) and 9.08 KJ/mol (for pore diffusion). With 5 wt% silicon addition, two steps existed with activation energies of 51.65 (for chemical adsorption) and 134.59 KJ/mol (for solid-phase diffusion). These values were slightly lower than the corresponding activation energies reported earlier for MgO-C and MgO-C-Al systems. Small differences could apparently attribute to the tortuosity differences of the samples.}, keywords = {Refractory,MgO–C,Silicon,Antioxidant,Kinetics,oxidation,PC,SC}, url = {https://www.ije.ir/article_71939.html}, eprint = {https://www.ije.ir/article_71939_9f54800e8529b0f19c7bf22ca6bdb28d.pdf} } @article { author = {Bagheri, Ahmad and Sadafi, Mohamadhosein and Safikhani, Hamed}, title = {Multi-Objective Optimization of Solar Thermal Energy Storage Using Hybrid of Particle Swarm Optimization and Multiple Crossover and Mutation Operator}, journal = {International Journal of Engineering}, volume = {24}, number = {4}, pages = {367-376}, year = {2011}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {Increasing of net energy storage (Q net) and discharge time of phase change material (t PCM), simultaneously, are important purpose in the design of solar systems. In the present paper, Multi-Objective (MO) based on hybrid of Particle Swarm Optimization (PSO) and multiple crossover and mutation operator is used for Pareto based optimization of solar systems. The conflicting objectives are Q net and t PCM and design variables are the geometrical parameters of solar system. The Pareto results of MO hybrid of PSO and multiple crossover and mutation operator methods are compared with that of multi-objective genetic algorithms (NSGA II). It is shown that some interesting and important relationships as useful optimal design principles involved in the performance of solar systems can be discovered.}, keywords = {Particle Swarm Optimization,multi,objective optimization,Multiple Crossover and Mutation Operator,Solar System,PCM}, url = {https://www.ije.ir/article_71940.html}, eprint = {https://www.ije.ir/article_71940_f6e9259cad6ebe3ac6982fe62d179bf3.pdf} } @article { author = {Liang, Qiaokang and Wang, Yaonan}, title = {Flexible Foot/Ankle Based on PKM with Force/Torque Sensor for Humanoid Robot}, journal = {International Journal of Engineering}, volume = {24}, number = {4}, pages = {377-386}, year = {2011}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {This paper describes the development of a novel humanoid robot foot/ankle based on an orientation Parallel Kinematic Mechanism for intelligent and flexible control. With three identical Universal-Prismatic-Spherical prismatic-actuated limbs and a central Universal-Revolute passive limb, the PKM can perform three degrees of freedom rotation motions. In order to enable the humanoid robot safely to walk stably on the irregular environment, the control system should possess intelligence and flexibility. As the force information is one of the most important inputs for the control system, a novel integrated force sensor is designed to measure the action force and moment at the foot when humanoid robot maintains balance or moves. The design possesses some interesting features such as high stiffness and compactness and is helpful for both reliable architecture design and performance improvement of the humanoid robot foot/ankle.}, keywords = {humanoid robot foot/ankle,parallel kinematic mechanism,flexible manipulation,force/torque sensor}, url = {https://www.ije.ir/article_71943.html}, eprint = {https://www.ije.ir/article_71943_7b711010f637963bc5f86822929346af.pdf} } @article { author = {Karbassi, Seyed Mehdi and Ostovari, Amir Hossein and Abghari, Ramin}, title = {Design of a New Instrument for Measuring Frictional Properties of Woven Fabrics}, journal = {International Journal of Engineering}, volume = {24}, number = {4}, pages = {387-392}, year = {2011}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {Friction measurement is one of important and interesting problems in the study of handle properties of fabrics. Different methods have been developed for measuring friction, such as sliding, KES and cyclic testing method. In this research, considering the possibilities of varying conditions in measuring friction, a new instrument by which the bottom surface of fabric can be moved and the top slider is kept fixed in order to prevent slider vibrations is used. In this method, the force inserted by an inextensible yarn connected to the trolley standing on four frictionless bearings was measured. The result of experiments confirmed 7.6% increase in correlation coefficient in the dynamic friction region for nine different test samples and about 4.6% reduction in coefficient of variation compared to the sliding type.}, keywords = {Frictional properties,Woven Fabrics,Dynamic friction,Static friction}, url = {https://www.ije.ir/article_71944.html}, eprint = {https://www.ije.ir/article_71944_96bb1750e7b8ee5f5d119e7c588307b8.pdf} }