New Page 1 In this paper, the oscillating two-dimensional laminar flow about a cylinder AND the oscillation of a cylinder in still water are studied. A finite volume method is applied to solve the Navier Stokes equations using SIMPLEC algorithm on a body fitted co-located O-type grid. In this study, the non-dimensional flow numbers, Keulegan-Carpenter AND Stokes numbers are chosen over a range where different laminar flow regimes are normally three-dimensional The results of this simulation AND comparison with numerical AND experimental works indicate the good capability of this two-dimensional model in showing the various regimes of. flow patterns AND vortex shedding. Considering the forces exerted on the cylinder, this study shows that in cases where the flow is of a regular type, there is a good match between longitudinal force presented by this work AND the one calculated through. Morrisons equation. But for irregular flows where the flow pattern changes in each cycle, there is less overlap AND the accuracy of Morrisons equation is reduced. Studying the time variation of the transversal force gives accurate information about the vortex shedding AND its frequency in each cycle AND mode changing. Since the flow mode changes continuously with time, the average of transversal AND longitudinal forces on consecutive cycles is not a good representation of the force exerted on the cylinder. On the other hAND, the model has satisfactorily reproduced the time variation of the tranversal AND longitudinal forces of apure mode, matching the experimental results.

Snake robots are hyper-redundant robots that are connected with one or two DOF joints. They offer a number of potential advantages beyond the capabilities of most wheeled AND legged robots. In this paper, KINEMATICS AND DYNAMICS of a planar multi-link snake robot in worm-like locomotion on an inclined surface is investigated. In this locomotion, Snake robot is able to move in the vertical plane. Body shape AND curvature function are used to determine the joint relative angles in accordance with the worm-like locomotion. Next, position, velocity AND acceleration of each link as well as center of gravity of the snake body are calculated. Newton principle is used to derive the dynamic equations based on KINEMATICS of the snake robot. Friction forces, as the only driving force is modeled using Coulomb friction. Effects of friction coefficient AND angle of inclined surface on the joint torques are investigated. It is shown that by increasing these coefficients the motor torques also increase. Webots software AND Lagrangian method are both used to verify the theoretical results. Additionally, KINEMATICS AND DYNAMICS equation presented in this paper may be used to generate other locomotions in vertical plane. Effect of link geometrical shape on motor torques is also investigated. Finally, FUM-Snake3 robot AND physical experiments are used to further validate the mathematical model.

Mobile mechanical manipulators are one of the automation aspects which were revealed in last years of twentieth century. These machines assume the responsibility of human AND gradually expAND the domain of their activities in industry. This paper is a presentation of the Sweeper Robot designed in the Robotic Laboratory of Iran University of Science AND Technology. The original design of this robot allowing to its gripper to constantly remain parallel to the ground is presented. The dynamic AND kinematical models of the robot have been computed. A software was developed in MATLAB to validate the kinematical AND dynamic models of the robot by comparison with the experimental results. Once the robot was built AND its systematic odometric error estimated by experiment, a control scheme for linear motions was developed to deal with this error. The approach is based on the introduction of an initial rectifying offset motion before starting the linear motion. Eventually, classical line tracking AND image processing algorithms were used to complete our robot AND the efficiency of our design to achieve its mission in picking AND placing different objects according to various algorithms.

The dynamic topic in high school physics books is a challenging topic we decided to investigate the cause of this weakness. For this reason we checked physical exam sheets in second-high school for the first semester in two high schools in Varamin city. We found that one of the problems is how to use Newton’ s second low. We designed a questionnaire for this problem. We give the useful results from the analysis of the answer sheets. These results can be helpful for the teaching dynamic topics. The dynamic topic in high school physics books is a challenging topic we decided to investigate the cause of this weakness. For this reason we checked physical exam sheets in second-high school for the first semester in two high schools in Varamin city. We found that one of the problems is how to use Newton’ s second low. We designed a questionnaire for this problem.

In most of the researches which has been conducted until now on the robot manipulator tracking control, it has been presumed which the kinematic of robot manipulator or Jacobian Matrix of robot from the joint space to the task space is quite known. However, none of the physical parameters in robot manipulator equations can be calculated by high accuracy. In addition, when the robot manipulator moves something, uncertainties occur in length, direction AND point of contact of end-effector. Hence, uncertainties occur on the kinematic of robot manipulator either, AND due to the different functions of the robot manipulator, its kinematic is changed as well. Therefore, ensuring stability of the closed-loop system in the presence of uncertainties in the DYNAMICS AND KINEMATICS of robot manipulator is quite challenging. In this paper, for overcoming on these uncertainties, we present our simple robust control for tracking the position of robot manipulator in the presence of uncertainties in the DYNAMICS KINEMATICS AND Jacobian Matrix of the robot manipulator. The proving of the stability shows the closed-loop system has Global asymptotic stability. Then, to overcome the practical problems of proposed control, amendments will be provided. The closed loop system with improved control has limited uniform stability. Since in many of the operations has been performed by the robot manipulator, transient error plays an important role. Due to this reason, the modified control structure is a changed in a way which could improve the transient error. Finally, for displaying the function of the final controller, a case study is implemented on a two-link elbow robot. Mathematical proof AND simulation results confirm the good performance of the proposed control.

The body freedom flutter phenomenon is one of the aeroelastic instabilities that occurs due to the coupling of the aeroelastic bending mode of the wing with the short-period mode in the flight DYNAMICS of the aircraft. By using the aeroservoelastic model AND applying closed loop control, this phenomenon can be suppressed in the operating conditions of the aircraft AND the velocity of this event can be increased. The simplest model aircraft capable of displaying this instability includes the flexible wing AND the planar flight DYNAMICS model. For this purpose, the wing structure is modeled using the Euler-Bernoulli beam AND, the theory of minimum variable state is used to model unstable aeroDYNAMICS to make the conditions suitable for modeling the system in state space. In the control section, the elevator is used as the control surface AND LQR theory with Kalman filter is used to body freedom flutter suppression. Finally, the effect of adding a closed loop control to increase the body freedom flutter velocity AND the limitations of this work are studied.

This paper examines a parallel robot with 5 degrees of freedom with a linear platform. Parallel robots have a restricted workspace, AND singularities make the workspace even more confined. So the behavior of the robot in the workplace is examined by focusing on KINEMATICS AND DYNAMICS. To do kinematic analysis, the constraint equations are developed using the geometric relations, AND the speed AND acceleration equations of the robot are derived. The Jacobian matrix is then calculated using the screw theory, AND the state of the singularities in the workspace is determined based on the Jacobian matrix. Considering the singularity AND physical AND geometric limitations, an algorithm for calculating the workspace is presented. In addition, the kinematic index of dexterity is investigated using the Jacobian matrix as a measure of the robot's closeness to the singular configurations. The results of solving kinematic AND dynamic problems are validated with the output of the simulation in MATLAB software.

One may say that The Open Society AND Its Enemies (OS) offered in 1945 the first complete elaboration of the general approach proposed by Karl Popper, namely his ‘critical rationalism’, a bold generalization of the fallibilist falsificationism in the domain of the empirical sciences masterly proposed in Logik der Forschung (1934). The political content of The OS has been critically discussed. Nevertheless, not all people insist on the equally important moral dimension of the book, giving it its unity, I submit. Without morality, no critical discussion, no reason, no open society, let us say in a nutshell. I would argue that according to Popper, a strictly Christian morality of love would not be the appropriate emotional companion of critical rationalism, but that the less demANDing moral emotion of sympathy or compassion is perhaps necessary to give it its force against violence. I give some support to this line of argument. In my view, Popper proposed a somewhat unarticulated critical rationalist ‘emotivism’ of sorts. The emotion of compassion is necessary for triggering our moral decisions AND values, which are the ultimate basis of the choice for a reason against violence.

Due to the stochastic nature of wind energy, allocating an appropriate investment incentive for wind generation technology (WGT) is a complicated issue. We propose an improvement on the traditional incentive, known as capacity payment mechanism (CPM), to reward the wind generators based on their performance exogenously affected by the wind energy potential of the location where the turbines are installed, AND therefore, lead the investments towards locations with more generation potential. In CPM, a part of investment cost of each generator is recovered through fixed payments. However, in our proposal, wind generators are rewarded according to dynamic forecasts of the wind energy potential of the wind farm where they are located. We use an auto-regressive moving average (ARMA) model to forecast the wind speed fluctuations in long-term while capturing the auto-correlation of wind velocity variation in consecutive time intervals. Using the system DYNAMICS (SD) modelling approach a competitive electricity market is designed to examine the efficiency of the proposed incentive. Performing a simulation analysis, we conclude that while a fixed CPM for wind generation can decrease the loss of load durations AND average prices in long-term, the proposed improvement can provide quite similar results more efficiently.