The current paper presents an inclusive survey about the AC to DC and DC to DC converters for brushed DC Motor Drives. An essential number of different AC to DC and DC to DC topologies and control techniques, applied on the brushed DC motor drives are presented. This extensive literature review exposes advantages, disadvantages and limitations besides giving the basic operating principles of various topologies and control techniques.
Condition assessment for critical infrastructure is a key factor for the wellbeing of the modern human. Especially for the electricity network, specific components such as oil-immersed power transformers need to be monitored for their operating condition. Classic approaches for the condition assessment of oil-immersed power transformers have been proposed in the past, such as the dissolved gases analysis and their respective concentration measurements for insulating oils. However, these approaches cannot always correctly (and in many cases not at all) classify the problems in power transformers. In the last two decades, novel approaches are implemented so as to address this problem, including artificial intelligence with neural networks being one form of algorithm. This paper focuses on the implementation of an adaptive number of layers and neural networks, aiming to increase the accuracy of the operating condition of oil-immersed power transformers. This paper also compares the use of various activation functions and different transfer functions other than the neural network implemented. The comparison incorporates the accuracy and total structure size of the neural network.
Sewage pumps have been among the main electromechanical equipment of the sewage and wastewater management facilities around Europe for over 30 years. Their operational life ranges between 15 and 20 years. Therefore, a significant proportion of that equipment is currently non-operational, and many of them must be disposed of in the forthcoming years. Although the "Waste electrical and electronic equipment" Directive (2012/19/EU) is the main related legislation, sewage pumps are not directly addressed. EcoDesign Legislation is the main legislation applicable on such cases. This work investigates the possibilities of recycling sewage pumps used in wastewater management facilities after their renovation or upgrade. Evaluation results indicate that there is high potential for material recovery and for significant economic benefit. Therefore, the recovery of materials and safe handling of non-operating industrial and possibly hazardous electrical equipment waste, could contribute to the minimization of their impact on the environment.
Abstract. This research took place just after the end of the protests following the killing of a 16-year-old boy by a policeman in Greece in December 2008. Participants (N = 224) were 16-year-olds in different schools in Attiki. Informed by the Politicized Collective Identity Model ( Simon & Klandermans, 2001 ), a questionnaire measuring grievances, adversarial attributions, emotions, vulnerability, identifications with students and activists, and questions about justice and Greek society in the future, as well as about youngsters’ participation in different actions, was completed. Four profiles of the participants emerged from a cluster analysis using representations of the conflict, emotions, and identifications with activists and students. These profiles differed on beliefs about the future of Greece, participants’ economic vulnerability, and forms of participation. Importantly, the clusters corresponded to students from schools of different socioeconomic areas. The results indicate that the way young people interpret the events and the context, their levels of identification, and the way they represent society are important factors of their political socialization that impacts on their forms of participation. Political socialization seems to be related to youngsters’ position in society which probably constitutes an important anchoring point of their interpretation of the world.
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