621 resultados para Instalações eletricas
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With the growth of the demand on electric energy in the last decades, the urban distribution and transmission systems have experienced a bigger necessity to improve on the substations, the automation procedures and techniques on the operation maneuvers of such systems, in a sense that better attends the quality levels, availability, continuity and operational reliability. In this way, the objective of the present paper is to perform a study of protection and control on an electrical industrial system involving the procedures of digitizing and maneuvers automatism utilizing operational techniques and other pertinent information used in a typical high-voltage Industrial Electrical System. Analysis were made on short-circuits to specify the main components of the 138 [kV] substation, in addition, there were used digital MiCOM relays to make the protection of the present elements. With that, a program was developed to allow the user to monitor the condition of circuit-breakers through a supervision screen being able to simulate some kinds of faults, as well as observing the characteristics of each device. This way, the importance of having a fast and reliable system that ensures the equipment’s protection and the industrial process continuity due to faults on the electrical system is noticeable. It’s important to highlight that all this digitizing was mainly favored by the development of digital technology on the last years, mainly on microelectronics, also with the appearance of supervision gadgets allowing the development of complex systems in supervision and electric energy control
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This study aimed to develop a computer program which systematizes the structural shielding design calculation in diagnostic radiology facilities. For this purpose methodology of the National Council of Radiation Protection and Measurements (NCRP 147[5]) was used. By comparative statistics studies, it was verified if reference parameters values suggested by the US publication correspond to the average national values. The World Wide Web was chosen because of its characteristics as a powerful mean of communication, especially in terms of the wide variety of useful resources and easy access. To compare the reference values of some parameters proposed by NCRP 147 to Brazilian average, studies about the normalized workload per patient, performance of X-ray tube and primary air kerma, unshielded, at one meter from the focal point of the X-ray tube were made. Through this research, relative differences were found. In workload values this differences reached up to 50% in mammography compared to those presented by the NCRP 147; in X-ray tube performance the percentage differences reached 69% in dental radiology, and air kerma results amounted 31% in fluoroscopy. This demonstrates the importance of validation of international protocols to local realities
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This work presents an intervention at the Guaratinguetá Railway Station and its surroundings, including this area in the urban context, at this moment isolated of the activities and citizen attentions, offering new activities on this commercial area. The selected area finds itself in a state of neglect and forgetfulness from the urban relations. Located between the periphery of the commercial center and the Paraiba do Sul River, the correlation is tension between the advancement of shops, the railway line, and the natural barrier of the Paraiba River. On the context of these limits, the railroad and the river stand as barriers for the center expansion and the flows that connect the old part of the town with the new part, which is growing and is called “post-city river”. These barriers have relegating properties around them to isolation, despite being located in the center. The area choice and this intervention seeks to break this isolation and the barrier flow, linking areas of opposite sides to form a leak through the barrier of the railway line. The pedestrian flow is prioritized in the project, this flow will be attracted by the program offered and by the new created areas, increasing the space utilization by users and breaking the isolation of urban activities. And entering the area in the context of life of city residents. The attraction of these new flows will be through the implementation of a Cultural Center, supplying a lack of city by spaces that offer this type of activity. Its implementation aims to attract and modify the activities of these spaces and the surrounding areas, one side facing the commercial center, and another facing the river, linking this two sides at the same time that this link provides the expansion of distance traveled and known
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Pós-graduação em Engenharia Mecânica - FEG
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Pós-graduação em Artes - IA
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Pós-graduação em Medicina Veterinária - FCAV
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The gas turbine (GT) is known to have: low cost of capital over the amount of energy, high flexibility, high reliability, short delivery time, commissioning and commercial operation at the beginning and quick departure. The gas turbine is also recognized for its superior environmental performance, manifested in air pollution containment and reducing greenhouse gases (Mahi, 1994). Gas turbines in simple cycle mode (SC) have long been used by utilities to limited power generation peak. In addition, manufacturing facilities use gas turbines for power generation units on site, often in combination with the process of heat production, such as hot water and steam process. In recent years, the performance of industrial gas turbines has been improved due to significant investments in research and development, in terms of fuel to electricity conversion efficiency, plant capacity, availability and reliability. The greater availability of energy resources such as natural gas (NG), the significant reduction of capital costs and the introduction of advanced cycles, have also been a success factor for the increased use of gas turbines to load applications base (Poulikas, 2004). Open Cycle Gas Turbine with a greater degree of heat to the atmosphere may alternatively be used to produce additional electricity using a steam cycle, or to compose a cogeneration process. The combined cycle (CC) uses the heat from the gas turbine exhaust gas to increase the power output and increase the overall efficiency of more than 50% second (Najjar, 2001). The initial discovery of these cycles in the commercial power generation market was possible due to the development of the gas turbine. Only from the 1970s that gas turbine inlet temperature and therefore the exhaust gas temperature was sufficiently high to allow a better efficiency in the combined cycle ... (Complete Abstract click electronic access below)
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Distribution networks are formed by long lines that carry electricity substations to homes and industries. These lines have associated impedance and depending on operating conditions of the network these impedances may vary. This paper provides a detailed analysis of the effects observed in studies of voltage drop, short circuit and electrical losses, when considered the drivers sequence impedances used in primary distribution network at different temperatures. Therefore, it is initially presented a calculation methodology and details the factors that influence the final values. The methodology presented tackles in a practical way the main factors that directly or indirectly influence the values of the impedances as an emblematic example and will be properly dealt with throughout the paper is the effect of temperature on the values of the sequence impedances. More specifically is dealt with the case of XLPE cables protected, by having a higher maximum operating temperature than the operating temperature of the network. The effects observed in the power flow generated when considering the impedance values at both temperatures were analyzed. The impedance drivers tend to increase with increasing temperature. Thus the impedance of the conductor XLPE protected will tend to be greater for the maximum operating temperature for which the operating temperature of the network, resulting in greater voltage drop and higher electrical losses
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Pós-graduação em Engenharia Elétrica - FEIS
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Pós-graduação em Medicina Veterinária - FMVZ
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Pós-graduação em Engenharia Mecânica - FEG
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Objective: the objective of this study was to estimate the prevalence of Burnout Syndrome in dentists in the public service in the city of Araraquara – SP and its association with the variables of interest. Material and method: The sample was made up of the dentists active in the public health network (n = 60). Socio-demographic data was collected. The Oldenburg Burnout Inventory (OLBI) was used. Result: Of the participants, 60.0% were female and the average age was 41.9 ± 7.6 years. A large number of the professionals displayed a normal perception of the work conditions, premises, materials and equipment. 63.3% of the individuals feel tired even before arriving for work, 58.3% need more time to relax and to feel better, 70.0% are unable to deal well with the pressures of work, 50.0% feel they have no energy during or after work and 86.7% do not consider the work to be a positive challenge. It was observed that 48.3% of dentists displayed Burnout Syndrome, 11.7% Detachment and 13.3% Exhaustion. There was a significant association between the presence of Burnout and gender (p = 0.020) and the work premises (p = 0.011), with men being the most affected and those that considered the work premises very poor. Conclusion: It was concluded that the prevalence of Burnout Syndrome among dentists is high, with men and those who consider the work premises bad being the most affected.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Animal models are an important tool in scientific research. It is known that this practice must be based on bioethical principles in order to impose limits about pain and suffering, or for inspecting proceedings and research site. This study has as aim to evaluate and present current legislation ruling animal research in Brazil, comparing it with other countries, as well as fostering bioethical reflection about this issue. For this, we present current Brazilian legislation and we have carried out international literature review and discussion. The articles were searched in PubMed data base, using the key words "bioethics" and "animal welfare". Nineteen articles from 1997 to 2013 were included. It was concluded the evident contribution of animal research for scientific research in several fields. It is morally relevant for humans, as rational beings, to secure humane treatment to animals contributing to research. The safest way to follow this path is establishing clear norms and studies well designed, involving society for assigning ethical norms. Thus, animal welfare would be guarantee.
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Pós-graduação em Artes - IA