List of Articles

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  1 - Numerical solution of hovering propeller performance at various blade pitch angles and revolutions with different turbulence models
  Behrooz Shahriari Mohammad Reza Hashemi
  In this research the validation of different turbulence models of a hovering propeller at different pitch angles and revolutions has been investigated. For this purpose, the pressure on the propeller surface at different cross sections has been calculated numerically by More

  In this research the validation of different turbulence models of a hovering propeller at different pitch angles and revolutions has been investigated. For this purpose, the pressure on the propeller surface at different cross sections has been calculated numerically by six different turbulence models and compared with the experimental data. In the first part, the effects of changing the blade angle have been discussed, in this case, the angles of 0, 2, and 12 degrees have been selected. The results showed that changes in the pitch angle of the propeller have led to an increase in the error rate of numerical calculations. At a high pitch angle and in the same chord section, the highest amount of error is produced in leading edge section of the propeller, among which the best model in terms of production error is the k-e RNG. Also, due to the possibility of the formation of shock waves, the S-A and k-e standard models have very large errors, which shows these models' inability to simulate rotating flow with shock waves. Manuscript profile
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  2 - Analysis and simulation of island mode operation in inverter-based microgrids with voltage droop controllers
  Babak Keyvani Bahador Fani Ghazanfar Shahgholian Mahnaz Hashemi
  Renewable energy sources are used as distributed generation (DG) sources in distribution networks. Inverter microgrids (MGs) in island operation are nonlinear systems with multiple dynamic modes. One of the main advantages of a microgrid is its ability to operate in isl More

  Renewable energy sources are used as distributed generation (DG) sources in distribution networks. Inverter microgrids (MGs) in island operation are nonlinear systems with multiple dynamic modes. One of the main advantages of a microgrid is its ability to operate in islanded mode, where the DGs are responsible for providing both active and reactive power requirements by themselves. The distinguishing feature of distributed generation, with power electronic interfaces, which usually work as voltage source inverters, is the flexibility to provide controlled and high-quality energy. In this paper, the dynamic model of a microgrid based on inverter voltage sources in the first level of control is used. The behavior of a microgrid in the time domain is simulated and the performance of a microgrid is shown in three different modes. The inverter source control model including power control loops, voltage control and current control loops as well as the LC filter of the source output in the dq biaxial reference device are used. The simulation results show that with conventional dropout strategies, the active power distribution is done properly between sources, but it is not accurate enough to distribute the reactive power between the resources of a microgrid. Manuscript profile
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  3 - Tolerance analysis (static and dynamic) of the gearbox assembly to achieve correct manufacturing tolerances
  Ehsan Mehrabi Gohari Iman Pishkar Mohammad  Alipour
  Tolerance analysis is one of the most important parameters affecting the quality and production costs of a product. In this research, using the tolerance analysis capabilities in Inventor software to set the tolerance of the speed reducer gearbox. First, the dimensions More

  Tolerance analysis is one of the most important parameters affecting the quality and production costs of a product. In this research, using the tolerance analysis capabilities in Inventor software to set the tolerance of the speed reducer gearbox. First, the dimensions of the conical rotor of the elevator gearbox were obtained by Geomagic reverse engineering software, and then the results were used in Inventor software to develop the gearbox model into a three-speed gearbox. Dimensional and geometric static tolerance analysis of this collection was done by using the worst-case, sum of square roots, process capability index and sigma methods. The results showed the worst-case method in tolerance analysis works more cautiously than other methods, as well as the residual sum of squares method, shows less laxity and interference than the worst-case method. Process index method, confirmed the assembly and in the sigma method, the sigma function considers the level of tolerance to be acceptable. Also, to ensure the correctness of the obtained tolerances, dynamic analysis has been done by using ADAMS software. The results showed that the set did not have any excessive slack or interference during movement. For validation, the results of this study were compared with Monte Carlo simulation results and showed good agreement. Manuscript profile
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  4 - A geometric approach for automatic guidance of marine loading arms
  Omid Kavianipour
  This paper deals with an assembly of articulated piping titled Marine Loading Arm (MLA). The MLA is developed to transfer liquids and gasses between jetty and ship in order to load or unload cargo such as cryogenic or high temperature products, and the most corrosive or More

  This paper deals with an assembly of articulated piping titled Marine Loading Arm (MLA). The MLA is developed to transfer liquids and gasses between jetty and ship in order to load or unload cargo such as cryogenic or high temperature products, and the most corrosive or hazardous products. The purpose of this work is to automate the conduction of a self-supporting MLA balanced via two single adjustable counterweights by means of a simple and practical approach. The proposed strategy complies with the specifications advised by the Oil Companies and International Marine Forum (OCIMF) and industry requirements. This strategy employs a geometric method to determine the appropriate voltage value to drive the hydraulic actuators, which in turn enables safe and rapid control of the MLA from the berth to the coastal tanker flange. Furthermore, validation of the results is performed utilizing the motion simulation in ADAMS software. Finally, the electro-hydraulic circuit diagram for the actuator movement is suggested. Manuscript profile
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  5 - Techno-enviro assessment and dynamic energy balance simulation of the domestic-scale solar heating system in Lebanon
  Mehdi Jahangiri Hasan Ali  Lotfi Nagafabadi Esmaeil  Moradi Seyed Mohammad  Noorbakhsh Hamed  Saghaei Hussein A.  Kazem Miqdam Tariq  Chaichan
  Statistics show that the residential and service sectors consume a large amount of the total generated energy in every country, most of which is spent for space and water heating. Solar water heater (SWH) as a recently developed technique can be used for supplying most More

  Statistics show that the residential and service sectors consume a large amount of the total generated energy in every country, most of which is spent for space and water heating. Solar water heater (SWH) as a recently developed technique can be used for supplying most of the energy consumption which is necessary to be considered for social and economic development and continuously improving the quality of life. Practical measures of SWH for space and water heating have not been developed enough and no feasibility study has been conducted on the subject in Lebanon. To do so, using the energy software such METEOSYN and TSOL as very important pre-fabrication tools for the simulation, modelling and analysis of every management applications for energy development-based systems, we study the potential of using domestic-scale SWHs in residential apartments at 2 stations in Lebanon. The results show that Tripoli station, which supplies 37.8% of its total heating needs, is more suitable than Riyaq, which could provide for 32.1% of its total needs. The results also demonstrate that both stations produce 2915.7 kWh for space heating and 5403.7 kWh for water heating annually using SWH. This method prevent the emission of 2.4 tons of CO2 pollutant gas annually based on fossil fuels. Manuscript profile
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  6 - Convergence of collocation Bernoulli wavelet method in solving nonlinear Fredholm integro-differential equations of fractional order
  Abdolali Rooholahi Saeed Akhavan
  We provide a computer method for solving fractional order nonlinear Fredholm integro-differential equations in this study. This method transforms the core issue into a set of algebraic equations using Bernoulli wavelets. The operational Bernoulli wavelet with fractional More

  We provide a computer method for solving fractional order nonlinear Fredholm integro-differential equations in this study. This method transforms the core issue into a set of algebraic equations using Bernoulli wavelets. The operational Bernoulli wavelet with fractional integration is obtained and used. It works particularly well for technical applications. The convergence of the suggested strategy is the most crucial aspect to note here. The collocation approach for this issue has a unique approximation since these requirements can be shown using mathematical principles and matrices theory. Finally, some pertinent examples for which the exact solution is known are used in numerical simulation to confirm the effectiveness and relevance. Alternatively, these examples will demonstrate the viability and correctness of the suggested approach. We provide a computer method for solving fractional order nonlinear Fredholm integro-differential equations in this study. This method transforms the core issue into a set of algebraic equations using Bernoulli wavelets. The operational Bernoulli wavelet with fractional integration is obtained and used. It works particularly well for technical applications. The convergence of the suggested strategy is the most crucial aspect to note here. The collocation approach for this issue has a unique approximation since these requirements can be shown using mathematical principles and matrices theory. Finally, some pertinent examples for which the exact solution is known are used in numerical simulation to confirm the effectiveness and relevance. Alternatively, these examples will demonstrate the viability and correctness of the suggested approach. Manuscript profile