In this research, in order to investigate the effect of the piezoelectric patch which is used as a sensor or actuator in rotating flexible structures such as a helicopter blade, the free vibrations of the rotating rectangular sheet with and without the piezoelectric patch have been presented. First-order shear deformation theory is considered for plate displacement and piezoelectric field. Considering the effect of Coriolis acceleration, centrifugal acceleration and centrifugal in-plane forces, the equations of motion are derived from Hamilton's principle and the electromechanical couple equation is obtained from Maxwell's equation. For piezoelectric, two electrical conditions, open circuit and closed circuit, which are used in sensors and actuators, respectively, have been considered. The equations are discretized with the help of the Numerical Method of generalized differential squares and the matrices of inertia mass, eccentricity, Coriolis and stiffness matrix are obtained. Natural frequency values for beam and rotating plate have been compared in Abaqus software. Also, the values obtained from the Numerical solution in MATLAB have been verified with articles and ABAQUS, which have high accuracy. The effect of parameters such as hub radius, rotation speed, sheet thickness, aspect ratio, piezoelectric patch thickness and applied voltage on the natural frequency of the system has also been investigated.

In this study, a novel Numerical approach is proposed to characterize the dissolution of rock minerals and wormhole propagation in carbonate rocks using the Darcy scale model. Accordingly, only the spatial variables of the governing partial differential equations are discretized, while the time variable remains continuous. Consequently, the partial differential equations are turned into ordinary ones, which are then Numerically solved by high-order Runge-Kutta Methods. The proposed approach is verified against the analytical solution in a 1D core model. Afterwards, it will be utilized to investigate the effect of multiple transport and reaction phenomena on the matrix acidizing in 2D carbonate formations. Also, the staggered grid technique is employed to accurately predict the wormhole patterns during several injection regimes. Compared to the previous studies, the proposed Numerical approach is less complicated and straightforward. Furthermore, the computational cost is more affordable.

In this paper, recommended spiral passive micromixer was designed and simulated. spiral design has the potential to create and strengthen the centrifugal force and the secondary flow. A series of simulations were carried out to evaluate the effects of channel width, channel depth, the gap between loops, and flowrate on the micromixer performance. These features impact the contact area of the two fluids and ultimately lead to an increment in the quality of the mixture. In this study, for the flow rate of 25 μl/min and molecular diffusion coefficient of 1×10-10 m2/s, mixing efficiency of more than 90% is achieved after 30 (approximately one-third of the total channel length). Finally, the optimized design fabricated using proposed 3D printing Method.

In this article, an efficient Method for approximating the solution of the generalized Burgers-Huxley (gB-H) equation using a multiquadric quasi-interpolation approach is considered. This Method consists of two phases. First, the spatial derivatives are evaluated by MQ quasi-interpolation, So the gB-H equation is reduced to a nonlinear system of ordinary differential equations. In phase two, the obtained system is solved by using ODE solvers. Numerical examples demonstrate the validity and applicability of the Method.

Today, most of the surface water and groundwater resources are exposed to contamination by different materials sewage. because most of the Methods have been used to restore the pollution intensity function for groundwater, representing a Method to restore pollution intensity function in rivers with more complex flow conditions is considerable. this research aim is to calculate the intensity function of the contamination source, by the Numerical solution of group preserving scheme, which has not been observed in other researches done so far. Group preserving scheme is an accurate Method to solve ill-posed problems. By implementing this Method the one-dimensional advection-dispersion equation with variable coefficients has been solved. The principle of the introduced backward solution Method is that by solving the dynamic systems in negative time steps, a general equation will be obtained, which can solve ordinary differential equations. The responses of this equation will lead to convergence of the equation and prevent the divergence of the data. three examples have been presented to show the accuracy of the forward and backward group preserving scheme, Firstly, using direct solutions of the river, the intensity of pollution concentration in the river is calculated, and the implicit finite difference Method is applied to verify the accuracy of the direct solutions. In the direct Method, the results of the two models were compared with statistical indexes in order to demonstrate the conformity of the two models. In the next step, by solving the backward group preserving scheme in two different examples, the concentration of pollutants upstream is simulated. Following the simulation and verification of the inverse model by direct solution, statistical indexes are used to evaluate the effectiveness of this Method.

Plastic hinge properties play a crucial role in predicting the nonlinear response of structural elements. The plastic hinge region of reinforced concrete normal beams has been previously studied experimentally and analytically. The main objective of this research is to evaluate the behavior of the plastic hinge region of reinforced concrete deep beams and its comparison with normal beams through finite element simulation. To do so, ten beams contain six deep beams, and four normal beams, under concentrated and uniformly distributed loading, are investigated. Lengths in the plastic hinge region involving curvature localization, rebar yielding, and concrete crushing zones are studied. The results indicate that the curvature localization zone is not suitable for the prediction of plastic hinge length in reinforced concrete deep beams. Based on the results it can be stated that in simply supported normal beams the concrete crushing zone is focused on the middle span, but in simply supported deep beams by creating a compression strut between loading place and support, the concrete crushing zone spreads along the compression trajectory. The rebar yielding zone of simply supported beams increases as the loading type is changed from the concentrated load at the middle to the uniformly distributed load.

Mansuri oil field, which is located at the South-West of Iran, has sand production problem and primary analyses proved the existence of this phenomenon in this field. Generally, there are three Methods to evaluate the sand production state which are empirical, Numerical, mathematical, and physical. Considering the Numerical capability to analyze complex geometries under high stresses condition, FLAC3D, which is a three-dimensional explicit finite-difference program for engineering mechanics computation, was employed to analyze sand production in this field. First, the Numerical model was calibrated using designed physical model and then, producing intervals and their perforations were modeled by numeric software. Its results showed that not only end-perforation instability is not the sole dominant mechanism in sand production, but also the effect of adjacent perforations on each other is more important. In this respect, there is an optimum pressure that causes perforations failure and catastrophic sand production. Mansuri field analyses demonstrated that the downhole pressure at its wells is near predicted optimum pressure and producing intervals are going to catastrophically produce sand.

Abstract Introduction: Silver conductive Lines are used extensively in electronics and optoelectronics. These Lines are deposited by different Methods. In this work, silver Lines were deposited by spraying diluted silver ink. Silver ink was synthesized by Lewis-Walker Method. Then, it was diluted by ethanol for spray deposition. Since substrate is at high temperature, both the deposition and annealing are performed at one step. Methods: For synthesis, silver acetate, ammonium hydroxide and formic acid were used as silver source, stabilizing agent and reducing agent, respectively. Finally, the obtained ink was diluted by ethanol. Spray deposition was done with nitrogen using air brush. Findings: Different parameters were investigated. First, ink to ethanol volume ratio of 1 to 10 was determined as optimized value. It was observed that 60 cycles of spraying gives layer thickness of 3 μm. Substrate temperature of 180˚C was determined as optimized value. Scanning electron microscopic (SEM) image showed that deposition at 40˚C led to discontinuous layer with island-like microstructure and deposition at 280˚C led to porous plate-like microstructure. But deposition at 180˚C led to continuous layer. X-ray diffraction patterns showed that silver layers deposited at 40˚C have a mixture of silver acetate and elemental silver phases, but layers deposited at 180 ˚C and 280 ˚C have pure elemental silver phase. Conclusion: It was observed that low resistance silver layer can be obtained by spray deposition of diluted silver ink. The silver layer deposited at optimized condition showed resistivity of 1.4 × 10-7 Ωm.