Amplificador de potência para baixa frequência

In this work we report the development of a tube amplifier built to be used in magnetic probe diagnostic of plasma. The probe is used to measure the magnetic field in the theta-pinch system presently running in our university. We present the calculations and procedures to determine the configuration of circuits and specify the components of the power supply, the preamp stage and the power stage. The circuit configuration and the characteristics of the components was obtained. A representative model of the system behavior gave the transfer function of the amplifier. Theoretical predictions of frequency response and the feedback effects were compared to the experimental values and showed very good agreement. The amplifier works between a frequency bandwidth of 20 an 30 kHz and supply a maximum power of 12 W

Estudo da utilização do balanced scorecard na gestão da qualidade e excelência operacional aplicadas a projetos de engenharia em sistemas de potência

The expansion of the electrical system is currently a subject of great importance to the development of Brazil. For its realization, large projects are needed, requiring large-scale investment and realization processes of great complexity. Thus, this type of project has a high strategic importance for the performance of companies that conduct. Seeking a way to determine a method to align traditional practices for measuring quality to the corporate strategic needs, this work is the study of the use of the balanced scorecard methodology, applying quality management and operational excellence, with a focus on projects in power systems. We analyzed some cases of successful application of the methodology in business segments in the next study, culminating in a proposed model of the method

Efeito do exercício prévio na determinação da potência crítica

The objective of this study was to analyze the influence of previous exercise on the determination of critical power (CP). Seven apparently healthy nontrained males, of 18 to 25 years, participated of this study. The subjects were submitted, in different days to the following protocols in a cyclergometer: 1) one progressive test until voluntary exhaustion for the determination of lactate threshold (LL), maximal oxygen uptake (VO2max) and its corresponding intensity (IVO2max); 2) six constant workload tests at 95,100 and 110% IVO2max until exhaustion with and without a previous exercise at 70% , in random order. The exhaustion times (tlim) at 95, 100 and 110% IVO2max were adjusted forme thress models of two parameters to estimate CP and anaerobic work capacity (AWC) [P=CTAn/tlim)+CP; tlim = CTAn/(P-PC); P=PC.tlim+ CTAn]. The model with the lowest standard error was considered for the estimation of CP. The tlim at 95% IVO2max was similar without (501 ± 140 s) and with previous exercise (473 ± 99 s). However, the tlim at 100% (381 ± 103 s and 334 ± 101 s) and 110% IVO2max (267 ± 163 s and 227 ± 68 s) was significantly longer with previous exercise. There was no significant difference in CP and AWCat conditions without (200 ± 27 W and 23 ± 11 kJ, respectively) and with previous exercise (212 ± 30 W and 18 ± 8 kJ, respectively). It can be concluded that the parameters of the relationship between power and time were not modified by the previous severe exercise

Transmissão de potência em corrente contínua e em corrente alternada: estudo comparativo

This paper presents a comparative study based on literature and examples in the literature, the two main technologies for the transmission of electricity at high voltage: alternate current transmission and direct current transmission. Inside the direct current transmission will be shown two technologies currently employed, transmission by current source and transmission by voltage source, contributing to a better understanding of them. The ultimate goal is to provide a text for consultation to identify key characteristics that influence the choice of future transmission lines

Localização de descargas parciais em transformadores de potência imersos em óleo mineral por meio de cápsulas piezelétricas de baixo custo e sistemas inteligentes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Relaxação Lagrangiana Aplicada ao Problema de Dimensionamento de Lotes em Máquinas Paralelas: Limitantes Inferiores

This paper addresses the single stage lot-sizing problem in parallel machines. Each item can be produced on any machine, and incurs a setup time before to start the production. The objective of this paper is to obtain lower bounds of good quality for this problem. A solution method is developed based on a reformulation of the problem and the Lagrangian relaxation of a set of constraints. Some computational results are presented comparing the proposed method with a method from the literature and with a computational package.

Elementos de manutenção de transformadores de potência

The intended purpose of this paper is to present the main commissioning tests for power transformers and the most used techniques in industrial segment, it is also discussed your results and consequences in the equipment’s normal operation. Also in this text, it is given specific information concerning a maintenance plan compatible to power transformers, with elements of preventive and predictive maintenance, exposing essential components, tests and the regulations current, showing how analyze and interpreted the results from this maintenance resources. Also in this paper is submitted the economic impact of damage to transformers and how the correct maintenance method can minimize them. The objective of this text is demonstrate the importance of the equipment and the benefits of proper maintenance, much of in financial terms as in electric system reliability

Venografia da porção distal dos membros de ovinos e caprinos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Implementação de um sistema de aquisição de dados da técnica de judô Osotogari utilizando dummy na realização do uchikomi

Pós-graduação em Engenharia Mecânica - FEG

Planejamento de reativos em sistemas elétricos de potência multi-área através de modelos estocásticos

Pós-graduação em Engenharia Elétrica - FEIS

Efeitos biológicos do laser de baixa potência sobre o cultivo de células-tronco mesenquimais provenientes do tecido adiposo e da medula óssea de cães

Pós-graduação em Medicina Veterinária - FMVZ

Avaliação do processo de reparação tecidual após Exérese realizada com bisturi convencional e bisturi harmônico Harmonic® de necrose induzida em língua de rato: estudo macroscópico e histológico

Pós-graduação em Biopatologia Bucal - ICT

Estudo comparativo sobre a eficácia de duas drogas de ação anti-inflamatória (Etoricoxib e Diclofenaco) após exodontia de terceiros molares inferiores inclusos.

In this article the authors clinically compare the efficacy of two different anti-inflammatory drugs - Etoricoxib (Arcoxia®) and Diclofenac (Olfen®) – in the control of postoperative pain resulting from the surgical removal of impacted lower third molars. Fifteen patients requiring the extraction of bilaterally impacted lower third molars were selected at the Department of Oral and Maxillofacial Surgery at the Araraquara School of Dentistry – UNESP. The drugs were randomly administered during the first and second surgical procedures. Pain was evaluated by means of a visual analogic scale for 72 hours following the surgical procedure. After statistical analysis of the results, the authors concluded that there were no significant differences in terms of postopoerative pain control between the two drugs studied.

Métodos de avaliação de risco de desordens músculo-esqueléticas nos membros superiores voltados para a odontologia

The dental professionals are exposed to many risks of development of occupational diseases and the musculoskeletal disorders in the upper limbs are the most common disease. This problem may result in lower productivity and / or early retirement. Therefore, early diagnosis should be done through a reliable and valid system of risk assessment. Because of that, this study set out to conduct a review of the literature on methods of risk assessment of musculoskeletal disorders in the upper limbs in dental professionals. Conclusion: It was concluded that the available methods for assessing the risk of musculoskeletal disorders in dentistry are self-reports, observational and direct. Among these methods, the self-reports were frequently used to detect the risk of musculoskeletal disorders among dentists, dental students and professionals from the dental team. Further studies should be performed in dentistry using observational and direct methods.