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.

The Water Column Separation phenomenon is one of the transient flow regimes, which is created under conditions such as the sudden closing of the valve or the shutdown of the pump in the water supply network. Hard pressure fluctuations and damages caused by the mentioned phenomenon require identifying and providing a solution to prevent it. By this purpose, the present article investigates the possibility of Water Column Separation in a Loop Water Supply Network using Computational Fluid Dynamics method. Next, the Effect of the inlet velocity on the pressures created due to the Water Column Separation was investigated. For software validation, the Loop System provided by Wang et al. (2017) was selected. After ensuring the efficiency of the software to model the phenomenon of Water Column Separation, simulation was performed at different speeds. Checking the simulation results indicated the occurrence of Water Column Separation in the Intended Network. Also, the Results indicated that with the increase of the input Velocity, the maximum value of the Pressure in the Network increases and its minimum value decreases. In such a way that with a 12% increase in the input velocity, the maximum pressure value changes by 11.8% and the minimum value by 14.26%. In general, it can be said that by controlling the Velocity as an effective factor on the pressure fluctuations of the Water Column Separation, this phenomenon and the resulting damages are prevented.

Providing optimal rehabilitation services for people with disabilities has always been recognized as a major concern of health Systems in all countries. Stewardship is one of the biggest challenges to provide rehabilitation services to people with disabilities in Iran. We advocate the Ministry of Health & Medical Education (MoHME) to take the lead as a steward of rehabilitation services in Iran, while the dedicated sections in the MoHME need to be determined, with a clear list of responsibilities and affiliations.

Boiler-turbine is a multi-variable and complicated System in steam power plants including combustion, temperature and drum water level. Selecting control Loops as a unique Loop in order to identify and control the boiler as a whole unit is a difficult and complicated task, because of nonlinear time variant dynamic characteristics of the boiler. It is necessary to identify each control group in order to accomplish a realistic and effective model, appropriate for designing an efficient controller. Both the effective and efficient performance of the identified model during the load change is of major importance. Here, not all parts of the System should be considered as a unit part, if determining and effective and realistic model is sought. The combustion Loop of the 320 MW steam power plant of Islam Abad, Isfahan is the subject. Due to the sensitivity and complexity of the System, with respect to its nonlinear and closed Loop characteristics, the identification of the System is conducted through intelligent procedures like recurrent adaptive neuro-fuzzy inference System (RANFIS) and nonlinear autoregressive model with exogenous input (NARX). The comparisons of the findings with actual data collected from the plant are presented and the accuracy of the procedures is determined

This study explores the motivational components within teacher rating Systems and their impact on professional growth motivation. Employing a Systematic review approach, it investigates texts pertaining to teacher rating Systems, motivation, and professional development literature. By examining various texts and research findings on teacher motivation, factors influencing teacher ratings based on general, specialized, and professional competencies, as well as experience, are identified. Drawing parallels with Herzberg's motivational theory, this study provides recommendations to bolster teacher motivation and job satisfaction through improvements in the rating System.