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 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.

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.

Facilities built in areas affected by earthquake activity, such as tunnels, which have always been an integral part of human life, must withstand both dynamic and static loading. It has led to the need for practical studies on the effects of earthquakes on underground structures and the factors affecting their destruction. For this purpose, in this research, at first different patterns of tunnel’s excavation were investigated and by using Plaxis 2D software and based on Tabas earthquake in Iran, sensitivity analysis on geotechnical parameters of the soil surrounding tunnel such as cohesion, friction angle, unit weight and modulus of elasticity was carried out, and the parameters whose changes have the greatest and least effects on the bending moment changes on the tunnel lining are introduced. The results show that tunnel excavation patterns significantly affect the bending moment, axial forces, displacements, and surface settlement of the tunnel. Often, by dividing tunnel excavation area to small parts, the values of bending moment, axial forces, displacements, and surface settlement of the tunnel decreases in static analysis. Also, outputs of sensitivity analysis on geotechnical parameters of the soil surrounding tunnel showed that modulus of elasticity of the soil surrounding tunnel has the most effect and cohesion changes have the least effect on bending moment induced on tunnel lining..

One of the important issues to be considered in the design of earth dams is seepage. In general, all soils are more or less water to pass through and accept the intrusion Therefore, in most cases follow the flow of water into the embankment dams is inevitable. If you can not control and restrict the flow of water in dams cause problems and adverse effects that sometimes "destruction and failure of the dam will follow. In this study, a comprehensive review has been numerical modeling of a two-dimensional percolation. After the the study has been presented dam and dam of Hamedan Abshineh been thoroughly studied. then, using the finite element method, two-dimensional and three-dimensional seepage analysis, about the dam was conducted and its results with the results of analyzes two-dimensional comparison, the sensitivity analysis carried out after the stage and perform two- and three-dimensional analysis of the impact of various parameters on the amount of leakage is discussed, at the end solutions to deal with this phenomenon in Hamedan Abshineh proposed dam Are. Due to the geometry of the sort of things can be very variable, and since the construction of three-dimensional model is very bulky and time consuming, so in this study, only one block parameters and specific (case study) used Are.All analyzes were carried out in this thesis Isothermal and interaction effects of heat stress on -transformation leak is ignored.

A two-dimensional numerical model has been developed to study wave breaking on a sloping beach. The basic elements of numerical model are Reynolds Averaged Navier-Stokes (RANS) equations that describe the mean flow motion of a turbulent flow; a k turbulence closure model that describes the turbulent transport and dissipation process; an efficient technique (VOF- Volume Of Fluid method) for tracking the free surface motion; and a new scheme developed by Lin and Liu (1999) for wave generation. Shoaling, breaking and overturning of solitary wave on a slope of 1/16 have been studied with the main emphasis on turbulence characteristics. Turbulence characteristics i.e., turbulence kinetic energy, k; turbulence dissipation rate, ; turbulence production, pr; turbulence eddy viscosity, vt; and their spatial distribution during the breaking process have been discussed in great details. Spatial distribution of turbulence characteristics and the order of magnitude have been found to be in agreement with existing experimental and numerical studies. The main characteristic of plunging breaking waves, the shoreward advective transport of turbulence, has also been investigated and numerically proved.

‎In this paper‎, ‎a numerical method for finding the numerical solution of the Burgers-Fisher and Burgers' nonlinear equations is proposed‎. ‎These equations are very important in many physical problems such as fluid dynamics‎, ‎turbulence‎, ‎sound waves and etc‎. ‎We describe a meshless method to solve the nonlinear Burgers’ equation as a stiff equation‎. ‎In the proposed method‎, ‎we also use the exponential time differencing (ETD) method‎. ‎In this method‎, ‎the moving least squares (MLS) method is used for the spatial part and the exponential time differencing(ETD) is used for the time part‎. ‎To solve these equations‎, ‎we use the meshless method MLS to approximate the spatial derivatives‎, ‎and then use method ETDRK4 to obtain approximate solutions‎. ‎In order to improve the possible instabilities of method ETDRK4‎, ‎Approaches have been stated‎. ‎Method MLS provided good results for these equations due to its high flexibility and high accuracy and having a moving window‎, ‎and obtains the solution at the shock point without any false oscillations‎. ‎The method is described in detail‎, ‎and a number of computational examples are presented‎. ‎The accuracy of the proposed method is demonstrated by several test simulations‎.

Let A be a C*-algebra with unit 1 and let S be the state space of A, i.e., S= {jÎA*: j³0, j (1)=1}. For each a Î A, the C*-algebra numerical range is defined byV (a): = {j (a): jÎS}.We prove that if V (a) is a disc with center at the origin, then ||a+a*||=||a-a*||.