26 resultados para Distorção harmónica

em Universidade Federal do Rio Grande do Norte(UFRN)


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The Methods for compensation of harmonic currents and voltages have been widely used since these methods allow to reduce to acceptable levels the harmonic distortion in the voltages or currents in a power system, and also compensate reactive. The reduction of harmonics and reactive contributes to the reduction of losses in transmission lines and electrical machinery, increasing the power factor, reduce the occurrence of overvoltage and overcurrent. The active power filter is the most efficient method for compensation of harmonic currents and voltages. The active power filter is necessary to use current and voltage controllers loop. Conventionally, the current and voltage control loop of active filter has been done by proportional controllers integrative. This work, investigated the use of a robust adaptive control technique on the shunt active power filter current and voltage control loop to increase robustness and improve the performance of active filter to compensate for harmonics. The proposed control scheme is based on a combination of techniques for adaptive control pole placement and variable structure. The advantages of the proposed method over conventional ones are: lower total harmonic distortion, more flexibility, adaptability and robustness to the system. Moreover, the proposed control scheme improves the performance and improves the transient of active filter. The validation of the proposed technique was verified initially by a simulation program implemented in C++ language and then experimental results were obtained using a prototype three-phase active filter of 1 kVA

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Due to major progress of communication system in the last decades, need for more precise characterization of used components. The S-parameters modeling has been used to characterization, simulation and test of communication system. However, limitation of S-parameters to model nonlinear system has created new modeling systems that include the nonlinear characteristics. The polyharmonic distortion modeling is a characterizationg technique for nonlinear systems that has been growing up due to praticity and similarity with S-parameters. This work presents analysis the polyharmonic distortion modeling, the test bench development for simulation of planar structure and planar structure characterization with X-parameters

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The scarcity of natural resources and the search for alternative energy sources promote a rapid change in the energy world. Among the renewable energy sources, solar energy is the most promising, presenting technology of greatest growth rate nowadays. Researchers around the world are seeking ways to facilitate their progress, developing technologies with higher efficiency and lower cost. As a contribution to global progress, this master thesis proposes the development of a strategy of maximum power tracking based on perturbation and observation method for photovoltaic systems. The proposed control strategy is based on active power balance of the system, with a reduced number of sensors. It also allows the PV system to act as a regulator of the power quality at the point of commom coupling (PCC), compensating the harmonic distortion and power factor of the current netw

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The present work deals with the synthesis of materials with perovskite structure with the intention of using them as cathodes in fuel cells SOFC type. The perovskite type materials were obtained by chemical synthesis method, using gelatin as the substituent of citric acid and ethylene glycol, and polymerizing acting as chelating agent. The materials were characterized by X-ray diffraction, thermal analysis, spectroscopy Fourier transform infrared, scanning electron microscopy with EDS, surface area determination by the BET method and Term Reduction Program, TPR. The compounds were also characterized by electrical conductivity for the purpose of observing the possible application of this material as a cathode for fuel cells, solid oxide SOFC. The method using gelatin and polymerizing chelating agent for the preparation of materials with the perovskite structure allows the synthesis of crystalline materials and homogeneous. The results demonstrate that the route adopted to obtain materials were effective. The distorted perovskite structure have obtained the type orthorhombic and rhombohedral; important for fuel cell cathodes. The presentation material properties required of a candidate cathode materials for fuel cells. XRD analysis contacted by the distortion of the structures of the synthesized materials. The analyzes show that the electrical conductivity obtained materials have the potential to act as a cell to the cathode of solid oxide fuel, allowing to infer an order of values for the electrical conductivities of perovskites where LaFeO3 < LaNiO3 < LaNi0,5Fe0,5O3. It can be concluded that the activity of these perovskites is due to the presence of structural defects generated that depend on the method of synthesis and the subsequent heat treatment

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This study aims to determine the influence of Digital Inclusion in school performance of students from public high school in the metropolitan area of Natal, through the use of computers in a pedagogical and Internet use.Throughout the paper we try to answer the question: The pedagogical use of computers connected to the Internet contributes to improving the academic performance of students in public schools in the RMNatal? To answer the research question, we focus on the database INEP on the infrastructure of schools and the bank rates of school performance. For both technical procedures performed to obtain the relationship between Internet and School Performance. Then the School Settings have been configured for Digital Inclusion and made crosses with the approval rates, distortion and failure. The survey results indicate that according to the classification established in: Included in School Settings, School Settings deficit, Adverse Environments School and School Settings Deleted, which has prevailed in the metropolitan area of Natal are the schools that are provided outside.

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Este estudo faz uma abordagem sobre as alianças eleitorais, destacando duas vertentes importantes nos processos de suas formações nas arenas políticas. Na primeira parte do trabalho é feita uma análise mais geral a respeito da problemática em questão. Onde dois ciclos políticos são analisados, apresentando o comportamento político-partidário dos partidos no Brasil. No primeiro ciclo, uma breve compreensão da política café-com-leite na República Velha, na qual, PRP e PRM dominam politicamente a arena nacional. O segundo ciclo, compreendido de 1945 a 1964, foram analisados os processos eleitorais estaduais e nacionais. Nestes, os resultados analíticos mostram o que refletem no comportamento político-partidário dos partidos do passado e do presente no país. Outro aspecto importante também abordado na primeira parte foi a verticalização das alianças eleitorais, a qual teve como objetivo impor harmonia partidária entre os partidos nas formações das alianças eleitorais. Revendo esse processo político, vimos que, a imposição da verticalização não resolveu o problema da inexistência harmônica dos partidos no ato da formação das alianças eleitorais tocante ao espectro ideológico. A segunda parte da pesquisa está dividida em duas partes. A primeira faz uma análise sobre a trajetória política do PT e suas políticas de alianças, que se inicia no V Encontro Nacional do Partido em 1987. Como consequência da expansão partidária, outras políticas de alianças são aprovadas pelo Partido dos Trabalhadores. Na segunda parte, é trabalhada as eleições municipais de 2008 em Natal, que observa analiticamente a campanha do PT e as alianças eleitorais realizadas pelo Partido para participar do pleito. Os velhos adversários políticos e oligárquicos formaram alianças com PT. Partido que nasceu combatendo as velhas práticas da política conservadora no nosso país, nos estados e nos municípios brasileiros

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The recent insertion of biodiesel derived from oily vegetables in the Brazilian energetic matrix calls for the study of some aspects that belong to it. The analysis of the carbonized energetic pattern concerns the paradigm of economic development that is constitutionally enshrined sustainable development which make environmental protection compatible with the needs of the economic rationality. This text is structured according to the ideas of modern hermeneutic that sees substantial value in the principles capable of create a harmonious relationship between law and society. The study of the constitutional principles to conduct a legal analysis about the National Program for Production and Use of Biodiesel - PNPB. The aim of the research is the study of PNPB ahead with the constitutional principles governing the economic order. To achieve this end we studied the sustainable development as a constitutional principle. We start with the notion that the thematic principles, and fundamental to understanding the dimension of sustainable development institute, since its concept is closely related to the applications of the principles enshrined in virtually all the constitutional order of the Western world. Then this was the National Energy Policy, initiating the approach by guiding principles of the National Energy Policy to develop the theme of public policy in the energy sector. Therefore, we studied the National Program of Biodiesel Production and Use - PNPB. From a technical introduction to the concept of biodiesel and a brief historical background, analyzing their advantages compared to fossil fuels predominantly used. Then it became a regulatory overview of the Brazilian legislation on the subject, central to understanding the plans and objectives pursued by the Brazilian government with encouraging the production of biodiesel. Finally discussed the tax incentives for production and use of biodiesel in Brazil. From the idea of federalism, characterized the tax as an instrument of state intervention in the economy. And finally it brought the tax incentives of Law No. 11.116/2005 in the face of the constitutional principles of economy and tax, and tax incentives from projects related to the Kyoto Protocol

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If, on one hand, only with the 1988 Federal Constitution the right to health began to receive the treatment of authentic fundamental social right; on the other, it is certain since then, the level of concretization reached as to such right depicts a mismatch between the constitutional will and the will of the rulers. That is because, despite the inherent gradualness of the process of concretization of the fundamental social rights, the Brazilian reality, marked by a picture of true chaos on public health routinely reported on the evening news, denatures the priority status constitutionally drew for the right to health, demonstrating, thus, that there is a clear deficit in this process, which must be corrected. This concern regarding the problem of the concretization of the social rights, in turn, is underlined when one speaks of the right to health, since such right, due to its intimate connection with the right to life and human dignity, ends up assuming a position of primacy among the social rights, presenting itself as an imperative right, since its perfect fruition becomes an essential condition for the potential enjoyment of the remaining social rights. From such premises, this paper aims to provide a proposal for the correction of this problem based upon the defense of an active role of the Judiciary in the concretization of the right to health as long as grounded to objective and solid parameters that come to correct, with legal certainty, the named deficit and to avoid the side effects and distortions that are currently beheld when the Judiciary intends to intervene in the matter. For that effect, emerges as flagship of this measure a proposition of an existential minimum specific to the right to health that, taking into account both the constitutionally priority points relating to this relevant right, as well as the very logic of the structuring of the Sistema Único de Saúde - SUS inserted within the core of the public health policies developed in the country, comes to contribute to a judicialization of the subject more in alignment with the ideals outlined in the 1988 Constitution. Furthermore, in the same intent to seek a concretization of the right to health in harmony with the constitutional priority inherent to this material right, the research alerts to the need to undertake a restructuring in the form of organization of the Boards of Health in order to enforce the constitutional guideline of SUS community participation, as well as the importance of establishing a new culture budget in the country, with the Constitution as a compass, pass accurately portray a special prioritization directed constitutional social rights, especially the right to health

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Body and writing: Lines and between-lines of production of knowledge in the classroom it is an ethnographic research, longitudinal character, based on experience while experienced educator of the Escola Municipal Professor Amadeu Araújo, located in the city of Natal-RN, from which are made reflections about texts written by students who have distorted age/education level, in the process of literacy. Here as initial goal: to discuss the production of students writing as a process body, considering the record of experiences and the impressions they have made during the teaching process. We initially by a conception of phenomenological body, by understanding it in its complexity, a phenomenon that is made from its relationship with the world and with the Other. The records examined were produced between the year 2000 and 2005 involving writings of 106 students, constituting a universe of 136 texts, from which, delimited a corpus of 27 texts. The relevance with respect to the theme and recurrence in which they were detected, were up to elements that allowed a systematization methodology, defining the following units of analysis: Body, written in everyday; body, written and sexuality; body, written and enjoyment poetics; body, writing and other stories. We used the techniques of search, participant observation, based on the actions and interactions body expressed during the experiment and the analysis of documents that consisted of students in the texts and secondary sources, among them, the records of daily class, reports and projects developed, as well as reports of my pedagogical practice, as a researcher inserted in the investigative process. The experience developed, showed a writing school able to express nuances of human complexity, showing that learning is made in the action body, crossed by various forms of language and pointing to the relevance of a pedagogical work able to articulate the dialogue between the written and registrations body of the students, as subjects of learning

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This paper presents a reflection on the use of robotics in education technology and the fostering of social and digital inclusion, unveiling a new field that has been outlined today. Robotics constitutes a tool still little known and not regulated at national level in education, there is little experience involving the tool in the Northeast. This research aims to reveal one of the first experiments with educational level robotics in Rio Grande do Norte. We present a field research conducted in a public school chancellor for a major institute of science and technology education of the state from seeking review of the robotics course, understand how they work and show their use in school and shows that contributions were generated for digital inclusion category students, based on speeches by teachers, engineers, management and students. As part of gathering information, we used the focus group technique, applied in two stages, one with groups of students, teachers and other school administration, as well as comments directed to the times when the robotics course was being finalized. As a result, we found that the school, through the robotics course is a provider of social and digital inclusion, since it awakens in the sample of students in this research knowledge enabler of social change. And that despite the student category do not understand the depth of meaning of inclusion, the same report in daily actions that integrate technology into their social context in harmony, enjoying its cultural citizenship in full

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This research work is focused to show the changes in educational administration from the agreements between the Mossoró / RN and the Ayrton Senna Institute IAS, for education provision. Nowadays, the partnership policy is a constitutive element of the reform of the Brazilian State, which dropped its action on social policies and to strengthen its regulatory role, encouraging private participation in planning, preparation and implementation of public policies, new printing setting the political-social. In this context, the 10 Note Management Programme, developed by the IAS, is part of the neoliberal logic of modernization of public school systems, focusing on results and developing strategies for control and regulation of schools work and its efficiency, effectiveness and greater productivity. The 10 Note focuses on two dimensions: the management of learning and teaching in networking, in a managerial perspective to overcome the culture of failure (expressed as age-grade, dropout and repetition rates in) and implantation of culture of success (as measured in the improvement of the indices). To understanding the process, we have delimited as the object of study, the process of implementing them mentioned program in the city, which its objective is to analyze implications for the school community from the perspective of democratic management, adopting the dimensions of autonomy and participation in institutional processes as a criterion of analysis. From a methodological point of view, the survey was conducted from a literature review and documentary about educational policy developed in the country since the 1990´s, seeking to understand, in a dialectical perspective, the political dimensions of teaching, training and performance of the subjects involved in the school work. Besides the empirical observation, it was also used semi-structured interviews with a methodological tool for gathering information and opinions about the partnership and the implementation of the 10 Note Management Program in the county. The interviewee participants were ex-former education managers, coordinators, school managers, secretaries and teachers. Regarding the dimensions inside the analysis (autonomy and participation), the research led to the conclusion: that GEED, under the guidance of IAS promoted regulation of school autonomy, set up the selection process for exercising the office of school administration and system awards to schools, pupils and teachers, subject to results, there is mismatch between the managerial logic and the democratic management principles, that the ideological discourse of modernization of municipal management coexists with traditional practices, centralizing patronage, which ignores the democratic participation in the school decisions processes, the goals of the partnership were partially achieved, since that the city has improved over the approval and dropouts, although the approval of the Education Municipal Plan of the rules institutional (administrative, financial and educational) and the creation of the Councils observed that the school community participation is still limited, not being characterized as a coordinated intervention, capable of promoting the transformation and improvement its quality in the county. In the same way, the orientation of networking is a limit to the autonomy of schools, given the external definition of goals and strategies to be adopted, along with pressure exerted through the accountability of each school community for their achievements

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

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This study aimed to validate tools for evaluating the ability and knowledge about blood pressure (BP) among nursing students. It is a cross-sectional, descriptive, quantitative and methodological study accomplished at the Universidade Federal do Rio Grande do Norte (UFRN), Universidade do Estado do Rio Grande do Norte (UERN) and a private university of the state. The sample consisted of 27 judges of research selected from the inclusion criteria: nursing, teachers of the semiology and/or semiotics discipline, with at least 1 year of experience, being from UFRN, EEN, UERN and private university of the state and and agree to participate voluntarily with the signing of the consent form. The research was development in three stages: construction of two instruments based on the scientific literature, resulting in a structured checklist consists of 28 items and a knowledge questionnaire with 12 questions; submission of the instruments to the judges, in the period from June to September 2012, which should evaluate each item in appropriate , appropriate with changes and inappropriate , addition to making an overall assessment of each instrument based on 10 requirements; validation and verification to the level of agreement among the judges, through the application of Kappa and Content Validity Index (CVI). Was used the consensus level greater than 0.61 (good) to the Kappa index and greater than 0.75 for CVI. Was approved by the Ethics in Research / HUOL. After being coded and tabulated, the data were analyzed using descriptive statistics. Of the 27 judges who evaluated the instrument, 77.8% are female, with a mean age of 36.6 (± 9.0) years, 63.0% worked in UFRN, 74.1% had academic master and 63.0% worked exclusively on teaching. Average length of teaching experience was 7.9 (± 8.0) years and in the semiology and/or semiotics discipline of 5.5 (± 6.7) years. In the judgment of structured checklist and questionnaire of knowledge about blood pressure mensurement any item/question was considered inappropriate since all obtained level of agreement within the indices established (CVI> 0,75 E Kappa> 0.61). In relation to structured checklist, of those 28 items present, 9 showed perfect concordance index (CVI = 1.00, Kappa = 1.00) and another 19 were considered appropriate with changes, especially with regard to clarity and vocabulary. In the questionnaire of knowledge, among the 12 questions that comprised, 7 had perfect concordance index and the others were considered appropriate with changes as requirements as clarity, vocabulary, and feasible sequence of instructional topics. In terms of a overall evaluating of instruments, the structured checklist got CVI of 0.94 and Kappa of 0.89 and the knowledge questionnaire, CVI of 0.97 and a kappa of 0.94. Both instruments proved to be valid as to their content, configuring it as clear and objective tools of assessment of knowledge and ability on blood pressure, being of nursing students as well as others students and health professionals, since the use of valid measures seeking to reduce the risk of distorting the results

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That study had the aim to validate an instrument to evaluate the knowledge about the Urinary Catheterization (UC) in males. Cross-sectional, descriptive, quantitative and methodological study, accomplished in Universidade Federal do Rio Grande do Norte (UFRN), Universidade do Estado do Rio Grande do Norte (UERN) and a private university from Rio Grande do Norte. Sample of 27 judges selected from the inclusion criteria: registered nurses, discipline of semiology and/or semiotics teachers, with at least 1 year of experience in the disciplines, to work at UFRN, UERN or in private university and agree to participate voluntarily with the signing of the Consent Form. Study developed in three stages: a) elaboration of twos instruments based on the scientific literature, resulting in a structured observation script type checklist consisting of 36 items and a knowledge questionnaire with 12 questions; b) submission of instruments to judges from June to September 2012, which should evaluate each item in "adequate," "adequate with changes" and "inappropriate", and make an overall evaluation of each instrument based on 10 requirements; c) and validation with a verification of the agreement level among the judges, through the application of Kappa Index (K) and Content Validity Index (CVI). It was used the consensus level higher than 0.60 (good) for Kappa Index and higher than 0.70 for CVI. The research project had favorable opinion from the Ethics in Research/HUOL (CAAE n. 0002.0.294.000-10). After being coded and tabulated, the data were analyzed using descriptive statistics. Of the 27 judges who evaluated the instrument, 77.8% are female, with a mean age of 36.6 (± 9.0) years, 63.0% worked in UFRN, 74.1% had master degree and 63.0% worked exclusively on teaching. The experience time mean in teaching was 7.9 (± 8.0) years and in the disciplines of semiology and/or semiotics in nursing was 5.5 (± 6.7) years. In judgment of the checklist and knowledge questionnaire, no step/question was considered inappropriate, since all achieved level of agreement within the established values. All the checklist steps obtained good to excellent K (between 0.60 and 1.00). Of the 36 items, 25 had excellent K (0.75 ≤ K <1.00) and excellent total K (K = 0.83). Regarding the IVC, all steps reached levels above 0.70 (between 0.74 and 1.00) and CVI total was 0.90. All questionnaire questions evaluated separately (K from 0.60 to 0.93 and CVI from 0.74 to 0.96) and generally (K from 0.79 to 1.00 and CVI from 0.89 to 1.00) had evaluation levels of content validity within the established values. The instruments were reformulated based on the agreement levels between judges and international guidelines, dissertations and scientific articles. Both instruments proved to be valid regarding to their content, allowing a clear and objective evaluation of knowledge and skills about UC, both nursing students as well as other students and health professionals, since the use of valid measures seeking the reduction of the risk of the results distorted

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Conselho Nacional de Desenvolvimento Científico e Tecnológico