Kinematic and Kinetic Modeling of a 3PRS mechanism is performed in this paper and its related controller is designed according to Computed Torque Method (CTM). This mechanism is a kind of spatial parallel robot with 6 DOFs, which is controlled using three active prismatic joints and three passive revolute joints and thus the system is categorized as constrained mechanism. Kinematic Modeling of the robot is performed using Homogenous transformation matrix and its related Jacobian matrix is exracted. Therefore the position and velocity relation between the joint space and workspace are provided both in its direct and inverse modes. Dynamic equation of the system is also derived using Lagrange equation in the joint space of the robot. Thus both of forward and inverse kinetic of the system are solved for the presented system. Finally, by the aid of the extracted Dynamic equation, the robot is controlled using Computed Torque Method (CTM). All of the Modeling are verified by simulating the equations in MATLAB and comparing the direct and inverse modes. It is shown that using the extracted Modeling and the designed controller for this parallel robot, the desired path can be easily tracked within the workspace of the robot.

In this study, a Dynamic based control algorithm for six-link quadruped locomotion is proposed. Up to now, a lot of researches have been conducted in the field of quadruped locomotion but most of the researches are based on the detailed Modeling of a robot and its surrounding. Such Methods are not able to generate a stable locomotion when the surrounding changes. However, the main characteristic of vertebral motion is the adaptability of their motions. So this is important to propose a control algorithm based on the robot Dynamics. The algorithms that can guarantee the stability are classified to two categories of Dynamic based and trajectory based Methods. The trajectory based algorithms need detailed information about gait which is not necessarily available. But the Dynamic based algorithms use some geometric constraints to reach a stabilizer controller. These geometric constraints generate the proper gaits. So in this study by employing the Dynamic based control algorithm, we proposed a controller for generating the Trot and Pace gait on a straight and flat path for quadruped robot locomotion. Given that the quadruped robot has four degrees of freedom, three geometric constraints are needed to provide rhythmic locomotion. In this study, the stability of quadruped locomotion has been proved using the Poincaré return map.

In the pharmaceutical industry, a great number of products are in the form of particulate solids. Since the mid-1980s, a new Method of powder generation has appeared involving crystallisation with supercritical fluids (SCF). The rapid expansion of supercritical solutions (RESS) is a promising new process for the production of small and uniform particles.Several variables can influence the RESS process: the nozzle temperature, preexpansion pressure, the nozzle diameter, and geometry. In this work, a two-dimensional Lagrange interpolation Method has been proposed to describe the size of nanoparticle forming through the rapid expansion of supercritical solutions, as a function of preexpansion pressure and nozzle temperature.

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 article, an attempt has been made to estimate the amount of sound transmission loss in a flat oval channel by applying the approach of statistical energy analysis. Correct estimation of sound transmission loss in an air conditioning channel is of great importance due to the harmful effects of noise pollution in the environment on human health. Simulation with the statistical energy analysis Method is a powerful approach to estimate sound and vibration in problems in which we deal with complex and multi-part systems; is considered. In this Method, first, a system is divided into several subsystems, and then by writing a matrix equation that includes the energy exchanges between subsystems and energy loss coefficients; It is investigated from the perspective of vibration and sound estimation.On average, the model presented in this research is able to estimate the sound transmission loss in different dimensions of the air conditioning channels according to the experimental results in the accuracy range of ± 2.5 dB. Considering that it seems that the results obtained from Modeling with this Method are in good agreement with the experimental data; The results of this research can be used as an efficient approach to estimate noise in oval shaped channels stretched in different lengths.

In this article complete numerical formulation for nonlinear analysis of planar structures made of hyper elastic materials with application in civil engineering is presented. Structural problems can be solved by finite element Method using complete Lagrange formulation. The presented formulation is for large strain problems and is applicable for a wide range of hyper elastic nonlinear materials. Generally in nonlinear finite element analysis large deformation and disordered mesh (distorted) is seen. As using disordered elements, isoparametric elements would have low precision. Hyper elastic materials like rubber are one of the most effective materials in engineering application. The high axial strength and large deformation capacity of these materials make them suitable for many applications. Theory of hyper elastic materials is proposed by references [13, 14]. These theories explain hyper elasticity behavior in complicated formulations. Therefore we are interested in studying planar hyper elastic elements with large deformation like rubber, leather etc. Eventually planar nonlinear elements formulation with hyper elastic behavior is presented for structures having large deformations and complete Lagrange formulation is used to analyze the structure. This formulation has been developed to analyze quadrilateral finite element models, which comparing to isoparametric 4-node elements is less sensitive to distorted meshing and doesn't have shear locking problem generated by geometrically distorted meshing. In order to deploy 2QACM benefits in nonlinear applications, complete Lagrange formulation 3Q4HY is used, numerical examples in geometric nonlinear problems have shown presented formulation's ability to prevent loss of precision in highly distorted meshing for 4-node hyper elastic elements. To show effectiveness of presented elements two numerical examples are presented. Q4HY elements efficiency in nonlinear analysis of planar elements made of hyper elastic materials is significantly obvious. The program is written in matlab environment for nonlinear analysis of hyper elastic problems. Two formulations are proposed and results have been compared with references results. Examples of rubber like problems have shown these formulations ability to analyze large strain structures. Numerical examples express four node element has less sensitivity to distortion in meshing in nonlinear analysis and can be used with good precision when element is diagonal, while calculated responses using 4 node isoparametric element may be inappropriate. 4 noded elements effect on developing a simple, applicable and valid nonlinear geometric analysis is significantly observed. Furthermore, a complete lagrangian formulation with a particular formulation by applying integration techniques to effectively establish stiffness matrix is presented. According to presented examples, the investigated elements have great potential in solving Hyper elastic problems.

Purpose: The present research was conducted to explain creativity, based on self-management and creative self-efficacy by mediating of educational engagement in elementary school students with learning Difficult. Method: The research Method was a descriptive-correlation Method with a path analysis design in the form of structural equations. The statistics society was included of students in 4th to 6th grads with learning problems that were engaged to educate in primary schools of Arak city in the academic year of 1400-1401, which were selected 200 boys’ and girls’ students (100 each gender) with learning problems as the research sample by using the purposeful sampling Method. Data gathering tools were include Colorado Questionnaire, Shaffer's creativity questionnaire, Karwowski creative self-efficacy, Houghton and Neck's self-management, and Wilborn's educational engagement, which were completed by teachers and parents of students with learning Difficult. The collected data were analyzed by using Pearson's correlation coefficients and path way analysis in SPSS and AMOS software. From structural equations Modeling Method was used to investigate the research model fitness.  Results: The findings showed that the research model have an agreeable fitness. Also acquired coefficients between variables parameters showed that meaningful direct effect of self-management dimensions and creative self-efficacy on educational engagement and creativity. In this means, by increasing the self -management and creative self-efficacy, there is a positive change in the degree of educational engagement and creativity in students with learning problems. So, the relationships between the variables of the model drawn in this research were confirmed.

A common Method for controlling a group of parallel converters in decentralized control strategy structure in an island microgrid, the use is the droop-down characteristics of frequency ω-P and voltage E-Q. However, the problem with using this Method is that the reactive power is not properly distributed (in proportion to the capacity of the micronutrients) between the micronutrients, which may lead to overload in the converters. Microgrids may also suffer from Dynamic stability problems such as power fluctuations, which can be increased by switching between active and reactive power control. To avoid this problem, the X / R ratio of transmission lines is an important parameter that should be carefully considered in the design of micronutrient controllers. By linearizing and simplifying conditions, the control system conversion function model becomes a single input-single output system, which is efficient enough to show the relationship between control parameters such as slope of droop characteristics and derivative sentences, virtual impedance, and voltage controllers. Using this model, stability conditions for different parameters are analyzed. Also, to improve power distribution stability, common droop strategies are modified by adjusting the slope as well as adding nonlinear sentence sections. This approach reduces the coupling between active and reactive power control and reduces the dependence of power distribution on grid parameters such as the X / R ratio. To evaluate the reliability of the proposed model, the simulation results in a sample island microgrid in MATLAB software are presented.