Reliability Study of Energy Harvesting from Sea Waves by Piezoelectric Patches Consideraing Random JONSWAP Wave Theory

One of the new methods for powering low-power electronic devices employed in the sea, is using of mechanical energies of sea waves. In this method, piezoelectric material is employed to convert the mechanical energy of sea waves into electrical energy. The advantage of this method is based on not implementing the battery charging system. Although, many studies have been done about energy harvesting from sea waves, energy harvesting with considering random JONWSAP wave theory is not fully studied up to now. The random JONSWAP wave model is a more realistic approximation of sea waves in comparison of Airy wave model. Therefore, in this paper a vertical beam with the piezoelectric patches, which is fixed to the seabed, is considered as energy harvester system. The energy harvesting system is simulated by MATLAB software, and then the vibration response of the beam and consequently the generated power is obtained considering the JONWSAP wave theory. In addition, the reliability of the system and the effect of piezoelectric patches uncertainties on the generated power are studied by statistical method. Furthermore, the failure possibility of harvester based on violation criteria is investigated. &nbsp

The Effect of Cardiac Rehabilitation Care Plan on Quality of Life in Patients Undergoing Coronary Artery Bypass Surgery

Introduction: Today, coronary artery bypass graft surgery (CABG) in many patients to treat complications of the disease is common. This study aimed to evaluate the impact of cardiac rehabilitation on quality of life in patients undergoing CABG was performed. Materials and Methods: In this study, a quasi-experimental (clinical trial) study of 50 patients after coronary artery bypass graft surgery procedure based on objective and applying the criteria for inclusion of patients (community access) selected. Rehabilitation program was conducted for 24 sessions. for evaluate of demographic data and quality of life, demographic and questionnaires was used. For analysis of data chi-square test and RMANOVA tests was conducted. Results: Results showed that participants in terms of demographic variables were not significantly different from each other. The results also vary between the different stages of research in physical function, role physical (physical limitations, bodily pain, general health, role emotional (emotional limitations), mental health, physical health components and quality of life were significant differences. Conclusion: The results of this research, cardiac rehabilitation intervention is indicated on life quality improvement. Therefore attentive to the issue of cardiac rehabilitation is necessary

Kinematic analysis and workspace determination of hexarot-a novel 6-DOF parallel manipulator with a rotation-symmetric arm system

Parallel mechanisms possess several advantages such as the possibilities for high acceleration and high accuracy positioning of the end effector. However, most of the proposed parallel manipulators suffer from a limited workspace. In this paper, a novel 6-DOF parallel manipulator with coaxial actuated arms is introduced. Since parallel mechanisms have more workspace limitations compared to that of serial mechanisms, determination of the workspace in parallel manipulators is of the utmost importance. For finding position, angular velocity, and acceleration, in this paper, inverse and forward kinematics of the mechanism are studied and after presenting the workspace limitations, workspace analysis of the hexarot manipulator is performed by using MATLAB software. Next, using the obtained cloud of points from simulation, the overall borders of the workspace are illustrated. Finally, it is shown that this manipulator has the important benefits of combining a large positional workspace in relation to its footprint with a sizable range of platform rotations. <br /