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The silverleaf whitefly, Bemisia tabaci (Hem.: Aleyrodidae), is a key pest of greenhouse crops. Nymphs and adults feed on plant sap and excrete honeydew, resulting in reduction of yield and quality. This pest has a high potential for developing resistant biotypes against different insecticides. Therefore, it is necessary to study the efficacy of different categories of insecticides against B. tabaci. In this research, efficacy of imidacloprid (0.5 l/ha), thiacloprid + deltamethrin (0.75 l/ha), pyrethrum (4 l/ha) andthiamethoxam + lambda-cyhalothrin (0.3 and 0.4 l/ha) with four replications were studied in a completely randomized block design in Yazd and Bushehr provinces of Iran. Mean (± SE) efficacy of imidacloprid, thiacloprid + deltamethrin, pyrethrum andthiamethoxam + lambda-cyhalothrin (0.3 and 0.4 l/ha) were 73.42 ± 3.41, 89.57 ± 2.86, 90.29 ± 2.79, 68.13 ± 3.37 and 75.62 ± 3.76% against B. tabaci nymphs 7 days after treatment in Yazd, respectively; while in Bushehr, they were 57.30 ± 3.37, 68.45 ± 4.65, 64.17 ± 2.87, 30.0 ± 4.56 and 53.0 ± 3.35%, respectively. Thiacloprid + deltamethrin, pyrethrum and thiamethoxam + lambda-cyhalothrin (at 0.4 l/ha) can be suitable candidates in IPM programs of B. tabaci.

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In this study, TL characteristics of muffler shells are simulated using analytical and numerical model. Noise generated by engines, is radiated out into the atmosphere at the radiation end of the muffler and also from the shell of the muffler. So, accurate prediction of sound radiation characteristics from muffler shells is of significant importance in automotive exhaust system design. In analytical method, an exact solution is obtained by solving the vibration equation of the shell and acoustic wave equations simultaneously. Then, in numerical model, with the aid of SYSNOISE, commonly used commercial boundary element software, the coupled structural FEM-BEM model is applied to predict the TL of muffler shell. The predicted results agreed reasonably well with the experimental results. The effects of important design parameters likes thickness and geometrical shape are studied to provide design guidelines.

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In this paper, three-dimensional boundary layer flows on wind turbine blades as well as separation event have been studied. At first, boundary layer and three-dimensional momentum integral equations were obtained for incompressible flow considering rotation effects. Next, the effects of pitch angle and the angle between the flow direction and rotation vector on the Coriolis terms were applied using geometry factor definition and Blade Element Momentum (BEM) theory. Then, the integral parameters and effective geometry factors on separation positions and stall structure were investigated for a rotating blade. The obtained results show that rotational ratio, aspect ratio and radial position are three basic parameters for separation occurrence and separation and stall can be delayed via controlling them. Moreover, the results show that the area near the root is strongly influenced by rotational effects. In addition, it is concluded that the centrifugal pumping due to rotation decreases the boundary layer thickness and delays separation especially in the near root region and increases the blade aerodynamic coefficients.

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One of the most important issues in industry, particular casting industry is to determine the internal structure of objects such as identifying the interfacial boundary configurations between material, identification of impurities or mechanical properties of the material. The objective of the present inverse problem is to identified simultaneously two regular interfacial boundary configurations and mechanical properties of the components of a multiple (three) connected domains using a discrete number of displacement measurements obtained from an uniaxial tension test. A unique combination of a global optimization method i.e. the Imperialist Competitive Algorithm (ICA) and local optimization methods i.e. Simplex Method (SM) along with the inverse application of the Boundary Elements Method (BEM) are employed in an inverse software package. A fitness function, which is the summation of squared differences between the measured displacements and computed at identical locations on the exterior boundary, is minimized. The obtained results (run-time and error-rate), clearly demonstrate the efficiency of this present algorithm (the Imperialist Competitive Algorithm and Simplex Method) to optimize the objective function and the estimation simultaneously two regular interfacial boundary configurations and mechanical properties.

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In this study, the results of two optimized and base blades of a horizontal axis wind turbine with aeroelastic point of view are compared . In order to optimization, the chord length and the twist angle of the blade at various radiuses have been calculated by BEM. The Results which are obtained from 2D Computational Fluid Dynamics (CFD) have been utilized to train a Neural Network (NN). In the process of airfoil optimization, Genetic Algorithm (GA) is coupled with trained NN to attain the best airfoil shape at each angle of the attack. Finally, the optimized blade is derived. In order to simulate the flow on two blades and obtain the aerodynamic forces, the blades and their surrounding regions are organized by unstructured grid. The SIMPLE algorithm and second order upwind scheme are used in numerical fluid flow simulation. The aerodynamic forces on the blades have been used for stress and strain analysis. At this point, in addition to the aerodynamic forces, inertia forces resulting from the rotation of the wind turbine blade is also considered. The aerodynamic results show that optimized blade has high efficiency. The results of the analysis of the stress - strain showed that maximum stress on optimized blade is less than base blade and optimized blade design is also more reliable than the blade base.

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In this paper, a useful method proposed for aerodynamic design of Megawatt wind turbine's blade based on Blade Element Momentum (BEM) theory‌. In this method first a preliminary design is done based on the ideal BEM and then a method have been offered for geometric modifications to approximate the geometry of the blade to a real and functionally one. The advantage of this method is that needed few design parameters that simplify the design procedure, however its results are in good agreement with 5MW NREL reference wind turbine assumed as validation case and show that with use of this method can achieve a good aerodynamic design. then the twist angle has been optimized using Genetic algorithm and Bezier curve with annual energy production (AEP) as the goal function. At the end, a 2.5 MW wind turbine has been design based on this method with considering the Lootak site specifications in province of Sistan and Baloochestan. Then 3D model of the blade has been made and CFD simulation applied on that for showing the designed turbine operation in real conditions and comparison with BEM method and there is acceptable compatibility between two analytical methods.

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In recent years, Underwater Acoustic Communications (UAC) has been a great matter of consideration because of its importance in different areas such as commercial and military applications. Underwater acoustic communications channel is known as a time-varying and doubly selective channel in both time and frequency domains. The orthogonal frequency division multiplexing (OFDM) modulation is an effective technique to communicate over challenging acoustic channels. In addition, using multiple-input multiple-output (MIMO) systems increases channel capacity which results in high data rate communications. Recently, basis expansion models (BEMs) have been widely used to estimate an underwater acoustic channel. In particular, when the channel is time-varying, the BEM model can effectively estimates the channel with a reduced number of coefficients and low computational complexity. To improve the performance of a MIMO communication channel, various beamforming techniques have been proposed in different areas. Inspired by the basis expansion modeling of an underwater acoustic channel, in this paper we develop a BEM based adaptive space-time beamforming for both the transmitter and receiver of an UAC. The Laguerre basis expansion model is employed in the linearly constrained minimum variance (LCMV) beamformer to obtain an adaptive scheme for updating the beamforming weights at the transmitter and receiver and to optimize the system performance in real-time.  Our Simulation results show that the proposed BEM based beamformer method improves the Bit-Error-Rate (BER) and Minimum-Square-Error (MSE) performance substantially for a Rayleigh fading underwater acoustic channel. In particular, our method improves the BER and MSE about 10dB and 4dB compared to the discrete prolate spheroidal sequence (DPSS) method.

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In this paper simulation of steady super cavitation phenomenon اhas been considered by using partial non-linear model of Boundary Element Method(BEM).The grid mesh used is fixed and the strength of dipole and source are constant on each element. With the assumption of a partial non-linear model the cavity condition is applied on the body with the assumption that cavity height is low. Thus there is not any calculation on the cavity surface, but it is restricted to only the panels on the body surface. Cavitation number is known at first and the cavity length is determined in every iteration. When the lengths obtained in two successive iterations are very close to each other it assumed to be the answer. Based on this method two Kutta conditions including Morino condition and Iterative Pressure Kutta Condition(IPKC) are studied to satisfy the wake surface condition. The application is a wing with NACA16006 section. Iterative pressure Kutta condition compared to Morino condition needs higher computational costs, but on the other hand leads to more accurate results. It has been shown that the simulation of the flow with super cavitation over wing leads to a pressure difference at the trailing edge of each strip if we use Morino’s Kutta condition. While if Iterative Pressure Kutta Condition is usedthe results are satisfactory. Comparing the results show that this method leads to very accurate predictions for the behavior of flows with cavitation, while significantly lower computational cost is required if we use the simple cavity closure condition.

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Podded drive systems are one the recent innovation in marine propulsion systems. Hydrodynamic analysis of this system is more complicated than conventional propeller-rudder systems. The different numerical methods have been used in the hydrodynamic analysis of podded drive systems. The range of these methods is from the potential method or potential/viscous approach to pure viscous methods. In this paper, we applied coupled approach in this regard. The main purpose of this research is developing a BEM/RANS coupled method for numerical simulation of podded drives. In the proposed Potential/Viscous coupled method, the flow around rotating part (propeller) is simulated by a BEM code. Then fixed parts (pod and strut) are modelled by a RANS solver. In RANS solver, the propeller can be substituted by a set of equivalent forces which called body force and added in the right hand of momentum equation. Two cycles are available for coupling the result between potential and viscous method. The coupled method is first studied and validated with a single propeller. Afterward, the propulsive performance of the podded drive systems is studied. The results include the propeller thrust coefficient, the propeller torque coefficient, and the axial force coefficient. The results obtained by coupled method are compared to and verified by the experimental data.

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This paper investigates the Tri-Tilt Rotor VTOL UAV. The aim of this study is to represent a comprehensive dynamic model, eleven degree of freedom at six flight phases (hover, descend, climb, forward, transient and cruise) and control the vehicle to reach best flight condition. For this purpose, the vehicle equations of motion are derived in tensor form and have been expanded in the coordinate systems, based on multi-body (vehicle and three electric motors) modeling approach in order to consideration of motors gyroscope effects on flight dynamic. Depending on vehicle flight phase, propulsion and aerodynamic forces and moments are determined separately. Blade Element Momentum Theory (BEMT) is used to obtain motors propulsion forces and moments at hover, descend, climb and forward phases. After that, with utilizing of controller for each channel flight, the trim condition is calculated and then for the sake of linearization using analytical method, dynamic and control matrixes are derived. This calculated model is qualified as linear model in order to design the model predictive and adaptive controller. For climb phase, as the nonlinear model receding from linear model, the linear model predictive controller performance was diminishing whereas the function of model reference adaptive control in spite of the uncertainties was better.

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Identification of the thermal conductivity of a functionally graded material (FGM) is considered as an inverse heat conduction problem. ‎In this investigation, the measurements of the temperatures on the portion of the 2D body where heat flux is specified as the boundary ‎condition and/or the heat flux on the portion of the boundary where temperature is specified as the boundary condition are used as ‎additional data needed to identify the thermal conductivity of the FGM domain in an inverse procedure. The thermal conductivity is ‎approximated as a quadratic function of only one direction, and therefore three constant coefficients should be estimated simultaneously.‎‏ ‏The solution of the direct heat conduction problem for‏ ‏FGM domain is obtained using the boundary elements method (BEM).‎‏ ‏The ‎imperialist competitive algorithm (ICA) which is an evolutionary and meta-heuristic global optimization is used to identify the constants ‎in the thermal conductivity function of the quadratic FGM. An inverse computer code is developed which employs the boundary ‎temperature and heat flux measurements data obtained by solving the direct boundary elements code with known thermal conductivity. ‎To show the feasibility and effectiveness of the developed inverse code, a number of example problems are solved and results are ‎verified.‎

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B-biotype Bemisia tabaci is a severe insect pest worldwide in many ornamental, agricultural, and horticultural crops. Control of this insect is obstructed by resistance to many AcetylCholinEsterase (AChE)-inhibiting insecticides, such as organophosphates and carbamates. In the present work, we evaluated the acetylcholinesterase inhibitory activity of six monoterpenoids namely α-pinene, terpineol, linalool, ß-myrcene, nerol and geraniol in vitro and in vivo. Inhibition of AChE of B. tabaci was measured by colorimetric method. The results showed that all of the monoterpenoids produced AChE inhibitory activity, with IC₅₀ values ranging from 0.96 to 26.85 mM. Alpha-pinene showed the most potent inhibitory activity (IC₅₀= 0.96 mM). Kinetic analysis showed reversible non-competitive type inhibition, revealing that these components might bind both the enzyme alone and the enzyme-substrate. Results demonstrate the AChE inhibitory activity as mode of action of these monoterpenoids at relatively high concentrations. Thus, this could be useful for investigation of new ecofriendly natural insecticidal compounds.

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In this paper, a simple numerical model is presented for analyzing trapezoidal alluvial valleys subjected to propagating obliquely incident plane SH-waves. As the literature review shows, the scattering effect of transient SH-waves on the surface of trapezoidal alluvial valleys has not yet been directly analyzed in the time-domain by half-plane BEM. In previous researches, the models were limited to the homogeneous single-material subsurface problems. Although in some researches, the mathematical formulation, numerical implementation, and transient analysis of two-dimensional non-homogeneous solids were presented as well, they were established to obtain the time-domain responses by the inverse Fourier/Laplace-transform from a mechanical problem point of view. Additionally, some researchers were used a full-plane time-domain BEM approach to present the time-domain responses for an alluvial valley. But in this study, based on an advanced half-plane time-domain BEM, the surface responses of a linear elastic trapezoidal alluvial valley are obtained due to propagating obliquely incident anti-plane SH-waves. In the use of half-plane time-domain BEM, the meshes are only concentrated around the interface of the basin. First, the problem is decomposed into two parts including a half-plane valley-shaped feature and closed filled alluvium. Then, the influence coefficients of the matrices are obtained by applying the method to each part. Finally, by satisfying the boundary/continuity conditions on the interfaces, a coupled equation is formed to determine unknown boundary values in each time-step. Then, all ground surface responses are also obtained in a secondary solution as internal points. After implementing the method in a general algorithm previously named DASBEM, several practical examples are analyzed to authenticate the obtained results beside prior published responses by other researchers. The main aims of this study are to present some applicable diagrams for use in engineering/operational projects, present a better view of alluvial valleys’ seismic behavior, and reveal the power of the developed algorithm in the analysis of complicated geotechnical problems. Thus, an advanced numerical study is performed to sensitize the surface motion of trapezoidal alluvial valleys with the variable of shape/impedance ratios as synthetic seismograms and three-dimensional (3D) amplification patterns. In the following, to complete the time-domain results, the transient response of the internal domain of the alluvium as well as the surrounding bedrock is shown by the snapshots’ views. Moreover, the sensitivity analysis is carried out to obtain the seismic amplification pattern of the surface by considering the key parameters including impedance and shape ratios, incident wave angle, and response frequency. Lastly, by collecting the maximum amplification of different scenarios and applying linear fit on the obtained values, the responses are summarized as a series of linear equations and tables. The results showed that the mentioned factors are very effective on the seismic response of the surface. The results of the present study can be used to complete the accuracy of existing codes around the subject of near-filed site effects.

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Surface quality and roughness are major effective parameters on the function of optic components. This study developed a new design of the Ball-End Magnetorheological finishing tool with the ability to mount on a three-axis CNC milling. In the new design, a new concept of the cooling system was used for cooling the internal and external surfaces of the electromagnetic coil, and optimizations on magnetic flux distribution were performed. With the aid of magnetostatic simulation in Ansys Maxwell software, the tool’s capability for producing magnetic flux density was tested. The capability of a new tool for polishing non-ferromagnetic BK7 glass was tested by selecting optimized process parameters like working gap and magnetizing current. An experimental magnetic flux density test with the gauss meter showed that the newly designed BEMRF tool can generate enough magnetic flux density for polishing BK7 glass. The finishing test showed the tool’s ability to create enough indentation force on the workpiece’s surface and reduce surface roughness.