Showing 5 results for mohamad sadegh
Volume 4, Issue 2 (9-2014)
Abstract
The present study aimed to analyze affecting factors on agricultural experts moving toward becoming agricultural e-marketing users. During a correlation-descriptive research method, variables of the study were prioritized through Theory of Planned Behavior (TPB) and correlation between variables and adoption was computed and finally the most effective variables on adoption were determined using logistic regression. Results showed that behavioral belief (Attitude), normative belief (Subjective norm) and control belief (Perceived Behavioral Control) were affecting adoption. Among personal abilities and skills, engagement in agricultural jobs had the greatest effect on adoption which was related to control belief of the respondents.
positive belief toward e-marketing and believing that had next great effect on decreasing traditional interferences respectively and variables related to behavioral belief had more important role in forming attitude of experts. Finally, agricultural companies were the most affecting variables on subjective norm of experts among other affecting components of agricultural market included in normative belief. Respondents selected network of agricultural advisory service companies which had an interference role between producers and customers as a proper option in e-marketing for local farmers. In this case, companies could merely deal with providing information of farmers’ products to suppliants through internet websites without playing direct role in buying and selling.
Volume 8, Issue 16 (Fall & Winter 2022)
Abstract
In the conceptual system of the Holy Quran, the only strategy of the believers in the face of enemies is "resistance" which has different dimensions. The views of lexicographers, commentators, as well as how translators translate some of these words (Specifically "Là tarkanou elà" In verse 113 of Surah Hood, "Anbaza elà" in verse 58 of Surah Anfal "Asheda" In verse 29 of Surah Fath and "Qhelzah" in verse 123 of Surah Tubah/Baraàt) are Different and numerous. The present article aims to use descriptive-analytical method and data evaluation to enumerate the meaning of these words based on the opinions of lexicographers and commentators and after analysis and critique, to provide a comprehensive and accurate meaning of them. Finally, based on the results, contemporary Persian translations (specifically Ansarian, Fooladvand, Makarem, Meshkini, Safavid, Rezaei, Moezi, Mesbahzadeh, Khorramshahi, Haddad Adel and Yazdi) are evaluated. The results of the present study indicate that in order to understand the exact meaning of these strategic words, paying attention to the context and their association with other words plays the most important role; which some lexicographers, commentators and translators have paid less attention. However, Meshkini and Safavi have been more successful in transmitting the correct meanings of these words than other translators.
Volume 15, Issue 6 (8-2015)
Abstract
In this study, a three-dimensional fluid field of an axial flow type micro hydro named Agnew has been investigated. The turbine installed at the Hydrulic Machines Laboratory (HML) of Iranian Research Organization for Science and Technology has been designed to generate 1 kw output power.All numerical simulations were performed using ANSYS CFX, a Computational Fluid Dynamic code, to investigate the performance parameters, such as efficiency and power, and results are validated against experimental data. Four different grid sizes are studied in accordance with the Grid Convergence Index (GCI) to investigate mesh independency of the solution. Results of several turbulence models were also examined to find out the Shear Stress Transport (SST) model in order to take into account the turbulence in the flow. Several turbulence models were also examined together with wall function in order to take into account the turbulence in the flow. A mixing plane interface plane was used to pass the disturbance of rotary domain to stationary domain. The obtained results show that a high resolution advection scheme, mixing plane to model the rotor-stator interaction together with a turbulence intensity of I=6% at the inlet, best matches with the experimental results. The difference between the efficiencies computed from both numerical approaches and experimental values may be ascribed to a numerical error, a model error or a systematic error.
Volume 20, Issue 8 (August 2020)
Abstract
The vortex tube is one of the widely used cooling systems in the industry. Investigating the effect of all input variables on the outlet cold temperature difference in laboratory state is time-consuming and costly. To this purpose, in the current study, attempts were made to model and predict the effect of all input variables on the outlet cold temperature difference of air and inlet air using adaptive neuro-fuzzy inference system (ANFIS) method. The ANFIS method was designed with three structures of fuzzy inference systems called subtractive clustering (SC) algorithm, fuzzy c-means (FCM), and grid partition (GP) with four types of input membership functions including trimf, gaussmf, gbellmf, and pimf. For model training and testing, 326 laboratory data were used. The developed models were compared using statistical parameters of correlation coefficient, mean absolute relative deviation, standard deviation, and root mean square error (RMSD) together with general desirability function. The results showed that GP algorithm with input pimf membership function with the greatest value of correlation coefficient (0.9975) and lowest value of RMSD for test data (0.4199) and general desirability function value of 0.71 is the best method to predict outlet cold temperature difference. Using the above-mentioned method, the most optimum state of vortex tube performance for industrial applications was found to be the use of 3 or 6 nozzels, at the pressure range of 0.55 to 0.6MPa and the nozzle angle of 20 to30 degrees, and for laboratory applications was obtained to be the use of 6 nozzles, at the pressure range of 0.55 to 0.6MPa, and the nozzle angle of 25 to 35 degrees.
Volume 22, Issue 2 (6-2022)
Abstract
In recent years, the use of supplemental damping devices to increase the capacity of structures against progressive failure due to explosion has received less attention. The main purpose of this research is to investigate the effect of using Triangular yielding metal damper called TADAS. in order to increase the capacity of an irregular three and nine-story steel moment frame buildings against pulse like seismic excitations and progressive collapse effect. For this purpose, seismic performance level of this structure has been evaluated and rehabilitated by TADAS damper. The seismic performance level of damper-equipped building was evaluated by nonlinear static analysis (pushover) and also nonlinear time history analysis under various pulse-like ground motions. In order to assess the performance of TADAS damper under progressive collapse phenomenon, 12 critical columns considering side and corner locations proposed by GSA code were selected to remove. Then considering the seismic nonlinear response of these columns under selected ground motions, four critical scenarios were selected for each building. According to irregularity of the structural plan the capacity of the rehabilitated structure was evaluated using nonlinear time history analysis. To simulate the progressive collapse phenomenon at first the internal column forces are evaluated before it is removed. These forces are dynamically applied to the structure as a nodal point load in addition to existed dead and live loads in five seconds after removing the column. After completing the amount of loading they kept unchanged for two second and finally the nodal point loads would be removed over a fraction of second and therefor the dynamic sudden column removal was simulated. The nonlinear response of the irregular TADAS-equipped building was computed through the step by step numerical integration method known as the Newmark’s β-method integration procedure using SAP2000 software. A fiber element model was employed to take into account the non-linear behavior of columns while for beam elements it is used plastic hinge model considering ASCE41 code. The dampers are also modeled using the link element in the software and the nonlinear plastic Wen model is assigned to simulate the nonlinear behavior of this element . The presented results include comparison of roof displacement diagrams, inter story drift and center mass acceleration for the structure with and without dampers in different failure scenarios. The seismic results show the ability of TADAS damper to improve seismic performance of irregular building. This control system could reduce the inter story drift of buildings at least 40% while the center mass acceleration increase 5.0% While the hysteresis diagram of dampers indicates their ability to suppress the response of this structure. These results indicate the success of the damping system in the simultaneous control of acceleration and displacement and indicate another result of this study. On the other hands the progressive collapse analysis results show the ability of TADAS damper to improve the capacity of the structure against four types of progressive failure scenario especially in scenario 2. The results showed that the vertical displacement was reduced at least 15%.
