In this paper, an improved mathematical model for flashover behavior of polluted insulators is proposed based on experimental tests. In order to determine the flashover model of polluted insulators, the relationship between conductivity and salinity of solution pollution layer of the insulator is measured. Then, the leakage of current amplitude of four common insulators versus axial, thermal conductivity and arc constants temperature was determined. The experimental tests show that top leakage distance (TLd) to bottom leakage distance (BLd) ratio of insulators has a significant effect on critical voltage and current. Therefore, critical voltage and current were modeled by TLd to BLd ratio Index (M). Also, salinity of solution pollution layer of the insulators has been applied to this model by resistance pollution parameter. On the other hand, arc constants of each insulator in new model have been identified based on experimental results. Finally, a mathematical model is intended for critical voltage against salinity of solution pollution layer of different insulators. This model depends on insulator profile. There is a good agreement between the experimental tests of pollution insulators obtained in the laboratory and values calculated from the mathematical models developed in the present study.

Every year, hundreds of fires occur in the forests and rangelands across the world and damage thousands hectare of trees, shrubs, and plants which cause environmental and economic damages. This study aims to establish a real time forest fire alert system for better forest management and monitoring in Golestan Province. In this study, in order to prepare fire hazard maps, the required layers were produced based on fire data in Golestan forests and MODIS sensor data. At first, the natural fire data was divided into two categories of training and test samples randomly. Then, the vegetation moisture stresses and greenness were considered using six indexes of NDVI, MSI, WDVI, OSAVI, GVMI and NDWI in natural fire area of training category on the day before fire occurrence and a long period of 15 years, and the risk threshold of the parameters was considered in addition to selecting the best spectral index of vegetation. Finally, the model output was validated for fire occurrences of the test category. The results showed the possibility of prediction of fire site before occurrence of fire with more than 80 percent accuracy.

The high demand for quality healthcare services in Portugal is generating concerns about meeting the optimum number of healthcare professionals in the private sector, such as doctors and clinicians. Critical interventions are currently in progress, aiming to provide quality healthcare that will be accessible and sustainable through actionable retention strategies such as investing and developing human capital, introducing better conditions of service to attract and retain talent in the private healthcare sector, and prioritizing the needs of patients. The objective of this study is to understand which factors promote the migration of physicians from the public to the private sector according to the theoretical assumptions of incentives. In this context, a phenomenological study was carried out, using semi-structured interviews with fifteen physicians working in the private health network. Content analysis was done using NVivo 12. The results indicate that performance evaluation in the private sector exists but has no alignment with incentives. The condition makes the private healthcare sector unattractive, however, other policies of remuneration remain promising. Current proposals that could revive the image of the sector include collective decision-making and strong labour relations advocacy for physicians in the private sector.

The study of the performance of high-efficiency heat pump systems has been a hot issue of general interest in the field of heat pump air conditioning. For the designed and developed two-stage casing tandem heat exchanger of heat pump system, the 3D finite volume method and the realizable k-ε model are used to numerically analyze the influence law of inlet fluid temperature and flow velocity on the overall heat transfer coefficient as well as the Nussle number of inner and outer tubes. The results show that decreasing the inlet water temperature or increasing the inlet refrigerant temperature can improve the overall heat transfer performance; Nu_in increases with the increase of water and refrigerant flow rates, while Nu_out increases with the increase of water flow rate but decreases with the increase of refrigerant flow rate; Nu_in and Nu_out both increase with the decrease of water temperature or refrigerant temperature increases.

Encouraging the social empowerment of persons with disabilities—also known as “people of determination” is a crucial step toward advancing equality and inclusion in our communities. Consequently, the current study aimed to identify the mechanisms for activating social empowerment for people of determination from the deaf category. Identify the most prominent mechanisms and proposals from the point of view of the deaf. The study used a social survey approach based on a questionnaire on a sample of (30) deaf males in the Kuwaiti Sports Club for the Deaf, and it is the full sample size. The study reached several results, the most important of which are: integrating deaf people with disabilities into jobs integrated into society, raising the level of cultural awareness of sign language, in addition to spreading awareness of how to deal with deaf people. The study presented some recommendations and proposals, including media focus on the deaf group, and working to hold conferences and workshops targeting the community to spread awareness about the deaf group.