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In end milling operation, cutting forces induce vibration on tool, workpiece and clamping devices which affects surface integrity and quality of the product. In this process, to select the optimum end mill and machine tool, the prediction of exact cutting forces is of prime importance. In the present work, modeling and simulation of cutting forces in end milling operation are performed. Instantaneous chip geometry is predicted using a 3D simulation software, the effect of cutting depth and feed rate are calculated and cutting conditions are predicted before any machining operation.

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In this study, to find the relationship between the government budget deficit and trade balance in Iran, a structural macro-econometric model is set up. In the model, government consumption expenditure increased by 20 percent annually during 2001-2010, so the government budget deficit increased relative to the baseline. The financing methods of budget deficit and relevant effects on trade balance were analyzed in 4 options. The results indicate that government budget deficit increases by adopting expansionary fiscal policy in all options. If the budget deficit is financed by borrowing from the central bank (the first option), it will raise the monetary base and finally worsen the trade balance and non-oil trade balance compared to the baseline.  If the budget deficit is financed by selling participation bonds to the public (the second option), it will reduce aggregate demand and finally improve the trade balance and non-oil trade balance compared to the baseline. If direct taxes and government spending are increased by the same amount (the third option), private consumption will decrease; and trade balance and non-oil trade balance will be deteriorated compared to the baseline. Finally, if the budget deficit is financed by the withdrawal of foreign currency reserves (the fourth option), oil revenues will increase, as a result the trade balance will be improved and the non-oil trade balance will be exacerbated compared to the baseline.  

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A numerical-analytical modeling technique was presented for predicting instantaneous energy absorption with axial tidal turbines in unsteady water flow. The goal of present paper is introducing a fast and stable integral solution approach with unique solution. This technique employs steady-state CFD data to approximate transient performance of axial tidal turbine in unsteady external flows. This solution technique was designed for modeling axial tidal turbine with convergent-divergent duct in water flow with unsteady boundary conditions. The governing equations for fluid flow were derived in the form of integral equations. The equation of one-degree of freedom motion for rotor was solved with fourth-order Runge-Kutta method and variation of parameters approach. CFD data for rotor and duct of axial tidal turbine were inserted as boundary values in integral equations of fluid flow. Two transient analytical equations were employed for approximating rotor torque and back pressure coefficient of tidal turbine. The results of integral solution approach were compared with transient CFD data in ANSYS-Fluent software. Many numerical simulations were performed to determine duct dimensions for maximum power enhancement in an axial tidal turbine.

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The purpose of this paper is to investigate the effect of viscoelastic ankle foot prosthesis on below-knee amputee gait cycle by using dynamic simulation of human walking. A two dimensional, seven segment model is developed to simulate normal and amputee entire gait cycle equipped with foot-ground contact model in order to simulate entire gait cycle in an integrated way. In the first step, optimization procedure was coupled with forward dynamic to simulate normal gait cycle. Next step was started by replacing ideal torque generator of ankle joint with passive elements that represents passive prosthetic ankle-foot, in order to simulate below-knee amputee gait cycle. The optimal coefficients of joints that were obtained from dynamic simulation of normal gait cycle were then used for amputee model’s intact joints. Three type of optimal passive ankle foot prosthesis were designed using forward dynamic optimization and the simulation results were employed to compare the performance of different prostheses. The results indicated that using viscoelastic ankle foot prosthesis decreases speed-normalized total work, cost function, dynamic effort and increases speed of the amputee model. Hence using viscoelastic ankle foot prosthesis can improve below-knee amputee walking pattern

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Blowby phenomenon of fuel-air mixture from cylinder-piston crevices, which occurs due to difference of in-cylinder and connected crevice pressures, influences engine performance. In the current work, experimental data of gasoline fuelled motoring condition at equivalence ratio of 0.9 were collected from a single cylinder research engine using skip spark technique. A relatively simple non-thermodynamic polytropic-base model was introduced and orifice-volume theory was coupled it; and gas flow through crevices was studied. From positive points of the model, it can be implied that the model predicts cyclic blowby without performing complex heat transfer and thermodynamic calculations. A verified thermodynamic simulation model including blowby sub-model was used to validate the polytropic-base model. Cylinder pressure evaluated by the thermodynamic model had good agreement with the measured pressure in the gasoline fuelled motoring condition at the equivalence ratio. First, in the polytropic-base model, output cylinder pressure of the thermodynamic simulation model was defined instead of experimental cylinder pressure and its blowby was evaluated. Then entering experimental cylinder pressure at equivalence ratio of 0.9 to the current model, cylinder mass and blowby to crevices were evaluated and compared with the predictions of the thermodynamic model. A very good agreement was observed between the obtained results and the results of the thermodynamic model. The new model showed maximum 6.88% cylinder mass lost around peak pressure position decreasing to 0.45% along the late expansion stage.

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In this study, the allocation of resources of National Development Fund (NDF) to economic sectors in foreign currency and Rial is evaluated by making a structural macro-econometric model that expresses the reality of Iran’s economy as much as possible. This model consists of 45 behavioral equations, 28 connecting equations and 88 identities. Behavioral equations are estimated by the ARDL approach in Eviews 9 software using annual data from 1959 to 2014. According to Theil’s U statistic and root mean square error (RMSPE), the simulation of endogenous variables indicates that model gives a good explanation of Iran’s economy mechanism. Regarding different scenarios for how to allocate resources of National Development Fund to different economic sectors, simulation results over the 2011-2014 period show that if 80% of NDF’s resources is distributed in proportion to the share of sector's investment in total investment in foreign currency and remaining 20% is allocated equally to agriculture and industry sectors in Rial, the highest rate of economic growth will be realized.

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The side branches in tomato plants have a great impact on tomato yield and fruit quality and the pruning work is now basically done manually, which has high labor intensity and high-risk factor. The elevated cultivation of tomatoes was taken as the objective of this research and 6 degrees of freedom P-R-R-R-R-R tomato side branch pruning robotic arm was proposed. The dynamic simulation of the robotic arm in the obstacle environment was completed by ADAMS. Simulation results showed the angular velocity and angular acceleration curves of each joint. A trajectory planning method combining Cartesian space and joint space was proposed to ensure that the robotic arm can avoid obstacles while effectively reducing the impact during operation.