Hekmati P.,Illinois Institute of Technology |
Yazdanpanah R.,Islamic Azad University at Larestan |
Mirsalim M.,Amirkabir University of Technology |
Ghaemi E.,Amirkabir University of Technology
IEEE Transactions on Industrial Electronics | Year: 2017
Slotless radial-flux permanent-magnet limited-angle torque motor with disturbed armature winding is analyzed in this paper. For the first time, the outer rotor structure is investigated for this type of the rotary actuator. The exact 2-D analytical modeling is applied to obtain the magnetic field parameters of the windings and excitation for both the outer rotor and the conventional inner rotor topologies. Also, the governing and geometrical equations are derived based on the analysis outcomes. Then, they are validated by applying the finite-elements tool. Both topologies are designed and compared with each other considering a variety of utilization parameters of these actuators. Avoiding saturation is considered as a designing criterion, which corresponds to the maximum torque production without distortion of linear characteristics in short-time operations. Experimental results show good accuracy of the theoretical design and numerical simulations. Comparison of the results shows significantly better performance of the new proposed actuator with the outer rotor structure against the conventional inner rotor type. © 2016 IEEE.
Rokhgireh H.,Islamic Azad University at Larestan |
Nayebi A.,Shiraz University |
International Journal of Solids and Structures | Year: 2017
This paper is concerned with the ratcheting prediction for steels. The yield surface evolution is integrated in the elastoplasticity analysis by a new proposed model. First, the new proposed model of Distortional Yield Surface (DYS) is developed and then ratcheting under different uniaxial and multiaxial cyclic loadings is investigated. The capabilities of the DYS model is assessed by using the results of various stress-controlled and strain-controlled tests under uniaxial loading condition and the cyclic uniaxial experimental results of Hassan and Kyriakides (1994a). In addition, the model prediction under multi-steps uniaxial loadings is also studied. Effects of DYS consideration in different uniaxial loadings are shown. Strain or stress controlled tests and combined stress-strain control experimental tests (Hassan and Kyriakides, 1994b) are used to be modeled by the present distortional yield surface approach. The biaxial experiments on CS 1018 thin-walled tubes (Hassan and Kyriakides, 1994b) are chosen to be compared with the present model results. With the incorporation of DYS, The new proposed model shows better prediction of uniaxial and multiaxial ratchetting in all ranges of experimentally tested parameters. © 2017.
Rokhgireh H.,Islamic Azad University at Larestan |
Nayebi A.,Shiraz University
Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science | Year: 2017
Correct determination of ratcheting strain is very important in cyclic loading. A new simple yield surface distortion model is presented and its effect on cyclic loading and ratcheting prediction is investigated in this research. Model of Baltov and Sawczuk was modified in order to be able to consider directional distortion of the yield surface. Movement of the yield surface center is modeled by Chaboche's nonlinear kinematic hardening model. Isotropic hardening was also considered. A triangular function is used and necessary cyclic plasticity relations are developed. Convexity of the proposed model is discussed and verified. Performance of the proposed model in ratcheting strain prediction is investigated in multiaxial non proportional loadings under different paths. Experimental results with stress, strain and combined stress-strain control paths are compared with the proposed model results. Incorporation of the yield surface distortion of this new model, predicts better ratcheting strain for different stress, strain and stress-strain paths. © 2017 Institution of Mechanical Engineers.
Barahmand N.,Islamic Azad University at Larestan |
Mozhdeh H.,Islamic Azad University at Larestan
IIOAB Journal | Year: 2016
The reduction of river profile due to the plants or other factors can create scour. The narrowing of flow stream in the location of bridge makes the water level rise in bridge upstream and increase of flow velocity. Consequently, the potential of deposit carrying or the river bed erosion intensity increases. in these cases, the erosion continues until the flow profile increases to the extent that the capacity of deposit carrying decreases becoming equal to that in bridge upstream and finally the erosion fails to continue. generally, the scour is created in hydraulic structure downstream, bridge piers and almost wherever scattered flow intensity increases locally. downstream area of separation where there are small and big eddies and the pressure is fixed is said to be wake. In laminate layer where the velocity is low, it is more likely for separation to happen than turbulent border layer. To investigate separation and its consequences on the bridge pier playing an important role in decrease or increase of scour. The range of Re is 10000 to 50000. The drag coefficient in all columns showed a decreasing trend versus Re. the drag of elliptical column had the lowest value. The greatest drag is related to square and column, the cylinder drag at high Re has a lower values than square and column which is due to pressure drag reduction from the movement of separation point to downstream resulting in smaller eddy behind the column and drag reduction. © 2017, Institute of Integrative Omics and Applied Biotechnology. All rights reserved.
Afifi M.E.,Islamic Azad University at Larestan
International Journal of Ecology and Development | Year: 2017
Flood can be occurred due to the different reasons. One of the new and challenging reasons in twenty-first century is land use changing issue. Environmental factors cause these events and the scrutiny of them shows that Human intervention in the natural water cycle through the vegetation in the aquifer of urban development and industrialization of societies has Unfavorable effects on Catchment Hydrology and causes flood intensity, increased pollution in downstream areas, Base flow and groundwater feeding reduction. Flooding is a complex and destructive natural phenomenon that causes a great damage every year. In order to plan for optimum utilization and natural flood control, which is the most important issue on earth and also in this country, more studies and much research is needed. Methodology: In this study, first the required data and statistics and information were obtained from the relevant organizations. This data includes 1:25000 maps, geological maps, satellite images and meteorological data. After applying necessary modifications on topographic maps and extracting Digital Elevation layer, the boundary of Catchment basin of Dry River will be extracted. Then using the SCS method, maximum possible runoff in the catchment is estimated. Hydrologic soil group, land use, type of Agriculture and hydrological status is calculated to obtain the CN. Findings: the result of SCS model shows that upstream land with High slope and bare lands and impermeable soils are more distributed and the Soil retention coefficient is low. Therefore the rate of runoff is also higher. By increasing the runoff on the surface of upstream land, maximum flow rate is also increased. With this increase the flood zones are more submerged. Conclusion: The investigation of the dry river shows that the amount of erosion and destruction of river margin in the straight and swept way in places with vegetation is more than the places with no vegetation “live” template. The various components of your paper [title, text, heads, etc.] are already defined on the style sheet, as illustrated by the portions given in this document. © 2017 by International Journal of Ecology & Development.
Rokhgireh H.,Islamic Azad University at Larestan |
Nayebi A.,Shiraz University
Mechanics Research Communications | Year: 2016
In this study, a yield surface distortion model coupled with nonlinear kinematic hardening model is proposed. The new yield surface distortion model is used to simulate proportional and non-proportional cyclic loading paths. Distortion of the yield surface and its nonlinear effects on the plastic flow have been studied by researchers and various models. However, these models have been rarely applied to different non-proportional cyclic loading paths. The yield surface evolution is obtained by the new model in cyclic loading and its results are compared with the experimental results of Dannemeyer . The new model with few constants predicts well the yield surface evolution under non-proportional loading paths which leads to well comparison of the numerical results with respect to the experimental results. © 2016 Elsevier Ltd. All rights reserved.
Norouzi M.,Islamic Azad University at Larestan |
Mansouri B.,Islamic Azad University at Kermānshāh |
Hamidian A.H.,University of Tehran |
Zarei I.,Islamic Azad University at Larestan |
Mansouri A.,University of Kurdistan
Bulletin of Environmental Contamination and Toxicology | Year: 2012
The purpose of this study was to determine the concentrations of metals, cadmium, chromium, lead and nickel in Liza vaigiensis and Johnius carutta, in order to: compare metal concentrations between two species with different gender, and to determine the significance between metal concentrations in the gill, liver and muscle. The highest mean concentrations of cadmium, chromium, lead and nickel in different tissues of these two fish species were found in the liver of L. vaigiensis at 0.68, 0.83, 0.37 and 1.42 μg g-1, respectively; while the lowest mean concentrations of cadmium, chromium, lead and nickel were observed in the muscle of J. carutta at 0.16, 0.16, 0.03 and 0.29 μg g-1, respectively. The results showed that the metal concentrations in both species were higher in the females than in the males (except chromium in gill and cadmium in muscle of J. carutta). Also, the results indicated that the metal concentrations were different among fish tissues (one-way ANOVA, p < 0.001), but there was no difference (except lead in gills of J. carutta) between sex (male vs. female). © Springer Science+Business Media, LLC 2012.
Akbari S.,Islamic Azad University at Larestan
10th International Conference on e-Commerce in Developing Countries: With Focus on e-Tourism, ECDC 2016 | Year: 2016
E-Commerce technologies have changed the economy bases of some business in the recent years. This paper represents in more details the industrial complexities which have changed the industrial economic structures around the world. Initially, we bring two factors that have been considered occasionally with the information technologies, such as, the changing balance of power in the specific industries and more efficient coordination of activities within and between enterprises. Then, we investigate three other factors brought by internet with high priority and effects on the value chains of industries. Simply stated these three factors are: disintermediation, disaggregation, and digital convergence. Although effects of these factors have been previously observed and studied, they have gained more significance in today technological era as the results of World Wide Web special benefits in the recent years. © 2016 IEEE.
Moosavi S.M.R.,Islamic Azad University at Larestan |
Sadeghi-Niaraki A.,K. N. Toosi University of Technology
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives | Year: 2015
Nowadays more advanced sensor networks in various fields are developed. There are lots of online sensors spreading around the world. Sensor networks have been used in Geospatial Information Systems (GIS) since sensor networks have expanded. Health monitoring, environmental monitoring, traffic monitoring, etc, are the examples of its applications in Geomatics. Sensor network is an infrastructure comprised of sensing (measuring), computing, and communication elements that gives an administrator the ability to instrument, observe, and react to events and phenomena in a specified environment. This paper describes about development boards which can be used in sensor networks and their applications in Geomatics and their role in wireless sensor networks and also a comparison between various types of boards. Boards that are discussed in this paper are Arduino, Raspberry Pi, Beagle board, Cubieboard. The Boards because of their great potential are also known as single board computers. This paper is organized in four phases: First, Reviewing on ubiquitous computing and sensor networks. Second, introducing of some electrical boards. Then, defining some criterions for comparison. Finally, comparing the Ubiquitous boards.
Karkon M.,Islamic Azad University at Larestan |
Rezaiee-Pajand M.,Ferdowsi University of Mashhad
Journal of Engineering Mechanics | Year: 2016
This study deals with the geometric nonlinear analysis of the plane problem based on the corotational formulation. Both analytical solutions and hybrid stress functional will be utilized in the proposed technique. A quadrilateral four-node element with drilling degrees of freedom is proposed for the finite-element analysis. The corotational method is applied for the nonlinear behavior. In this way, small strains and rigid body motions can be separated. Based on analytical solution, the hybrid stress scheme is used in the local coordinates for small strains. By using Allman's quadratic displacement, the boundary condition for this element is introduced. In this approach, added drilling degrees of freedom increase the accuracy and robustness of the element. Furthermore, the corotational formulas are written in the local and global coordinates system to derive the nonlinear relations. These equations were solved by using the arc-length algorithm. To investigate the accuracy and capability of the suggested element, several numerical tests are performed. Findings prove the advantage of the proposed element in the geometric nonlinear analysis of plane problems. © 2016 American Society of Civil Engineers.