Regulador automático de tensão robusto utilizando técnicas de controle adaptativo

The stability of synchronous generators connected to power grid has been the object of study and research for years. The interest in this matter is justified by the fact that much of the electricity produced worldwide is obtained with the use of synchronous generators. In this respect, studies have been proposed using conventional and unconventional control techniques such as fuzzy logic, neural networks, and adaptive controllers to increase the stabilitymargin of the systemduring sudden failures and transient disturbances. Thismaster thesis presents a robust unconventional control strategy for maintaining the stability of power systems and regulation of output voltage of synchronous generators connected to the grid. The proposed control strategy comprises the integration of a sliding surface with a linear controller. This control structure is designed to prevent the power system losing synchronism after a sudden failure and regulation of the terminal voltage of the generator after the fault. The feasibility of the proposed control strategy was experimentally tested in a salient pole synchronous generator of 5 kVA in a laboratory structure

Estabilizador de sistema de potência para máquinas síncronas de polos salientes utilizando a transformada Wavelet

The power system stabilizers are used to suppress low-frequency electromechanical oscillations and improve the synchronous generator stability limits. This master thesis proposes a wavelet-based power system stabilizer, composed of a new methodology for extraction and compensation of electromechanical oscillations in electrical power systems based on the scaling coefficient energy of the maximal overlap discrete wavelet transform in order to reduce the effects of delay and attenuation of conventional power system stabilizers. Moreover, the wavelet coefficient energy is used for electric oscillation detection and triggering the power system stabilizer only in fault situations. The performance of the proposed power system stabilizer was assessed with experimental results and comparison with the conventional power system stabilizer. Furthermore, the effects of the mother wavelet were also evaluated in this work

Controlador adaptativo por posicionamento de pólos e estrutura variável aplicado ao controle de geradores eólicos baseados em máquina de indução duplamente alimentada

In the last decade, the renewable energy sources have present a major propulsion in the world due to several factors: political, environmental, financial and others. Within this context, we have in particular the energy obtained through wind, wind energy - that has highlighted with rapid growth in recent years, including in Brazil, mostly in the Northeast, due to it s benefit-cost between the clean energies. In this context, we propose to compare the variable structure adaptive pole placement control (VS-APPC) with a traditional control technique proportional integral controller (PI), applied to set the control of machine side in a conversion system using a wind generator based on Double-Fed Induction Generator (DFIG). Robustness and performance tests were carried out to the uncertainties of the internal parameters of the machine and variations of speed reference.

Estratégia de conversor para interligação de sistemas de geração eólica à rede elétrica

Currently, there are several power converter topologies applied to wind power generation. The converters allow the use of wind turbines operating at variable speed, enabling better use of wind forces. The high performance of the converters is being increasingly demanded, mainly because of the increase in the power generation capacity by wind turbines, which gave rise to various converter topologies, such as parallel or multilevel converters. The use of converters allow effective control of the power injected into the grid, either partially, for the case using partial converter, or total control for the case of using full converter. The back-to-back converter is one of the most used topologies in the market today, due to its simple structure, with few components, contributing to robust and reliable performance. In this work, is presented the implementation of a wind cogeneration system using a permanent magnet synchronous generator (PMSG) associated with a back-to-back power converter is proposed, in order to inject active power in an electric power system. The control strategy of the active power delivered to the grid by cogeneration is based on the philosophy of indirect control

Estudo da oxidação do metabissulfito de sódio contido no efluente da carcinicultura

The shrimp farming is a process of creation of shrimp that has been growing rapidly in the country, occupying a meaningful space in the Brazilian exporting. In 2003, this activity presented a volume of 60 millions of tons and 220 millions of dollars, being the main generator of employment and income of the primary sector of the northeast economy. However, it is a new activity with c.a. five years in the Rio Grande do Norte State and therefore needs investment in the technological area. Among the wastewaters of this activity, the sulphite solution is being usually applied in the process of fishing, i.e. retrieval of the shrimps from the farming. The aim of this work is to present the oxidation experimental results of the sulphite that may be and to determine what it s the most efficient method, trough laboratory experiments. The measurements were carried out in a mixing reactor inserting air and with hydrogen peroxide addition with and without UV light. The solutions were prepared synthetically with concentrations found in the wastewater of fishing and also collected in locu. The oxidation process using air was monitorated by iodometric analysis for the sulphite and the oxidation using hydrogen peroxide was evaluated with turbidimetric analysis for sulphate, by spectrophotometer. The sulphite was totally oxidized in both processes. The experimental results permit to conclude that the oxidation by hydrogen peroxide is more efficient and allowed to determine the optimum operational conditions in terms of concentration and time of treatment

Objetivos e conteúdos no ensino de física para adultos: um estudo de caso

The dissertation presents the learning, production and results of a study with a group of adult students of a high school level class in a night time public school at the Zona Oeste district of Natal-RN. As a teacher of Physics of these adult students, whose age is between 17 and 65 years, we felt the need to deepen our knowledge about the specifics of these students and build ways of teaching which would lead to a more significant educational process beside them. Among these ways of teaching, we emphasize, first, the performance of an extra-class activity that triggered the students' oral narratives about their life stories. Such narratives have led us to prioritize, as goals of teaching: socialization and the rescue of the search for a permanent learning, self-esteem and skills development to promote the exercise of autonomy. The students' previous contacts with the country life showed to be extremely significant for their memories and motives, suggesting the theme "Nature" to be adopted as a matrix for generative themes to be adopted during the teaching and learning moments with them. Considering these results, we construct a teaching proposal for continued work with the class, with which we chose the "Climate" as a guiding theme of this proposal, here presented and analyzed. In addition to a movement between problematizations developed in a thematic framework - through the initial questions of the students -, and those in a more conceptual approach - that we induced -, we have adopted as central methodological aspect the use of oral and written language, both as an exercise of dialogue, Freire's perspective, such as a structural element of cognitive processes, the perspectives of Vygotsky and Bakhtin. The development of the proposal was registered by audio and teacher and students´ regular written records, for 1 month and a half. As positive outcomes of the proposal, we emphasize the changing attitudes of students, showing a significant increase of their initiative in participating of the classes, besides a creative and critical use of arguments during the situations studied

Utilizando as ciências espaciais e a astronáutica na construção de atividades práticas em ensino de física

In this work we consider the use of new technologies fron the Space Science and Astronautical, in the learning process, incorporating technical and conceptions of physics Spatial what can take on the response of some problems what there are a lot insistent in populate the mind of professors and followers regarding agreement of these conceptions into the level Average. Intending to bring another contribution to Physics teaching practice, especially Classical Mechanics, but introducing many introductory concepts from Modern Physics, since this topic is considered of great interest for teachers and students, for it involves high technology. It s advanced manufacturing demand certain processes that make possible the application of those concepts

Uma nova tecnologia no pensamento de Herbert Marcuse: arte e técnica na sociedade unidimensional

This dissertation addresses the issue of technology in the work of Herbert Marcuse, explaning the merger between technology and domination that result in a totalitarian technological apparatus. Thus, technological civilization is supported and justified by a rational technological apparatus in the society, we have come not only the philosophy of Marcuse, but other great thinkers too, like Heidegger, Hegel, Marx. We also present a debate involving the philosophy of science, logic and linguage. Marcuse points to the need for a new technological rationality that emerge from a new sensibility, where the technique would allow a new relationship between man and nature. From then on, would emerge the need for a new subject. This transition would be possible by means of sensitivity, where art would become the art of live. With the link between art and technique made possible by new sensitivity, the author leaves one of its main contribution: he leaves open the possibility for the subject to choose new targests for technological development

Uma nova tecnologia no pensamento de Herbert Marcuse: arte e técnica na sociedade unidimensional

This dissertation addresses the issue of technology in the work of Herbert Marcuse, explaning the merger between technology and domination that result in a totalitarian technological apparatus. Thus, technological civilization is supported and justified by a rational technological apparatus in the society, we have come not only the philosophy of Marcuse, but other great thinkers too, like Heidegger, Hegel, Marx. We also present a debate involving the philosophy of science, logic and linguage. Marcuse points to the need for a new technological rationality that emerge from a new sensibility, where the technique would allow a new relationship between man and nature. From then on, would emerge the need for a new subject. This transition would be possible by means of sensitivity, where art would become the art of live. With the link between art and technique made possible by new sensitivity, the author leaves one of its main contribution: he leaves open the possibility for the subject to choose new targests for technological development

Arranjos urbanos e subjetivos contemporâneos na invenção de territórios turísticos

We seek consistency empirical and analytical rigor to the concept of touristification in the course of the contemporary arrangements of subjectivity and urbanity stations through a landscape of social (dis)encounters between residents and foreigners living in the capital of Rio Grande do Norte, Natal. In the last three decades the city has become a major destination country for national and international tourism, making tourism an important monitor of choreography in search of synchrony between cities and subjectivities, orchestrated by the cyclical crises and the relentless battle for systemic capitalistic expansion and survival. We proceed with an ethnographic and cartographic inspiration in Ponta Negra, where the waterfront redevelopment in 2000 conducted by the government, influenced the implementation of various establishments, services and practices related to the construction of Natal s major industry hub of tourism and entertainment. We proposed an arch-genealogy of touristification inspared on Michel Foucault analytical perspective, increased by authors in confluence or in different theoretical and methodological approaches, among which stand out Karl Marx, Gilles Deleuze and Felix Guattari, Michael Hardt and Antonio Negri. The reflections that initially turned to the advancement of the sphere of consumerism as the issue capable of articulating the developmental trajectory of the capitalist system and the practice of tourism, promoting some effects (un)desirable in the conflictual dynamics of the condition of the district of Ponta Negra, territory each again (re) produces the designs to meet the consumption by affluent portion of the population and foreign, encountering social exclusion and inclusion differentiated a growing trend. We go forward with an analysis of the "liberation of desire" phenomenal features of the process of producing subjective, providing a breakdown of the recent world s financial crisis initially, but proved social and political crisis also, through a plot derived from the operation of real estate speculation, which Natal is mainly caught through touristification, showing the outlines of a generalized crisis in establishing a new order buoyed by the emergence of a context "biopolitical" since it is a major route that uses the capital to survive and expand, while guiding the process of "strategic beautification" held in Ponta Negra, problematized by us. We conclude by assessing the appropriateness of proposing on further analysis to explore the establishment of a "new social ontology in terms of interference touristification ongoing and the constitution of a "new order" local/global, away from that characterize a system's capitalist overcoming, try to give emphasis in the current stage of the radicalization of a capitalistic utopia

A experiência de depressão na contemporaneidade: uma compreensão fenomenológico-existencial

The depression is one of the most common forms of getting ill nowaday. Due to the increase in incidence of depression cases registered worldwide, this theme has been the subject of important studies, especially regarding the symptomatological description and biological etiology of the disease. This research had the objective to understand the unique experience of depression experienced by people who recognize themselves in depression, under the focus of existential phenomenology of Martin Heidegger. To reach the proposed objective, individuals narratives interviews were conducted with four participants, starting from the triggering question, "from your experience, how is for you to being depressed?". The survey revealed that depression affects the whole person and is related to stressful life contexts. Depression was narrated as an experience of disempowerment and lack of self esteem and personal worth. The collaborators of the research referred to the depression from sad, angry, bored and pessimistic mood. The time is experienced as a restriction to the projective opening towards the possibilities of being in which the future is seen as catastrophic and the past lived as debt and guilt. The corporeality, in depression is experienced through the weight, fatigue and pains for no reason. The space is lived from the notion of fall and collapse. We also realized the desire for isolation and avoidance of social contact. Suicide is desired and represents the end of the suffering in life. The depression has proved, still, very stigmatized, because it is discredited and misunderstood. The stigma also addressed to the experience of hospitalization and the unsuitability to the socially imposed standards of beauty, which generates enough suffering to the depressed person. The medication was described based on its positive effects, as a balance and suffering reducer, but also as a producer of dependence. Were also identified according to the collaborators, traces of selfdemand, ordenality and being-for-others, characteristic of typus melancholicus. This study contributes to an understanding of the depression that goes beyond the merely biological perspective and symptomatology of the pathology. The investigation of the depressive experience, through the lens of Heidegger's phenomenology, showed us the phenomenon of the depression in their singularity, complexity and multiple meanings, showing the close relationship between the formation of the depression and the context of personal and social life of the participants

Membranas de quitosana micro e macroporosas : preparo, caracterização e estudos de permeabilidade

Two methodologies were proposed to obtain micro and macroporous chitosan membranes, using two different porogenic agents. The methodologies proved to be effective in control the porosity as well as the pore size. Thus, microporous membranes were obtained through the physical blend of chitosan and polyethylene oxide (PEO) on an 80:20 (m/m) ratio, respectively, followed by the partial PEO solubilization in water at 80 ◦C. Macroporous chitosan membranes with asymmetric morphology were obtained using SiO2 as the porogenic agent. In this case, chiotsan-silica ratios used were 1:1, 1:3 and 1:5 (m/m). Membranes characterization were carried out by SEM (scanning electronic microscopy), X-ray diffraction, Fourier Transform Infrared Spectroscopy (FTIR), Thermal analysis (TG, DTG , DSC and DMTA). Permeability studies were performed using two model drugs: sodium sulfamerazine and sulfametoxipyridazine. By transmission FTIR it was possible to confirm the complete removal of SiO2. The SEM images confirmed the porous formation for both micro and macroporous membranes and also determined their respective sizes. By thermal analysis it was possible to show differences related with water sorption capacity as well as thermal stability for both membranes. DTG and DSC allowed evidencing the PEO presence on microporous membranes. The absorbance x time curves obtained on permeability tests for micro and macroporous membranes showed a linear behavior for both drugs in all range of concentration used. It was also observed, through P versus C curves, an increase in permeability of macroporous membranes according to the increase in porosity and also a decrease on P with increase in drug concentration. The influences of the drug molecular structure, as well as test temperatures were also evaluated

As pessoas com deficiência no mercado de trabalho: expressão das desigualdades sociais

This work was developed in the extent of the Post Graduation Program in Social Service of the Federal University of Rio Grande do Norte. It talks about the process of inclusion of the disabled people in the Job market in Mossoró-RN, bringing for the academic debate relevant thematic for the Brazilian society, for the profession of Social Service and similar areas and for the people with deficiency. It has the objective to apprehend the determiners that make possible the process of the disabled people's inclusion in the Job market in Mossoró, having as parameter the National Politics for the Integration of People Bearers of Deficiency. The critical theoretical perspective is backed in Marx's ideas for the understanding concerning the work, as well as in Pochamann, concerning the job market, regarding the exclusion/inclusion category is based in Martins, Yasbek and Sposati and on deficiency in the National Politics for the Integration of the Disabled People. The research is of qualitative nature and it took as subjects 26 (twenty-six) people, being 09 (nine) people with deficiency, inserted in the formal job and regulated market, and 17 (seventeen) managers of private companies and public institutions of the city of Mossoró-RN. For the collection of data we used techniques of nonsystemic observation, semi-structured interview and documental analysis. The results of the research mark that any modality of the human workforce used in the current context, they are functional to the capitalism and they move forward towards exploration, alienation and subordination of the work to the capital; the National Politics for the Integration of the People with Deficiency expresses and reproduces the contradictory dynamics of the class society, it reflects the neo liberal shades through the selectivity and of the articulation among the federated beings and organizations of the civil society for its operational system; there is a misproportion between the percentages of the quotas and the amount of people with deficiency inserted in the job market, just corresponding to a tiny numeric magnitude; the developed activities are of low social status and it is expressive the amount of workers that receives between one and two minimum wages. These data drive us to infer that the mentioned politics make possible, partly, the inclusion of the disabled people in the job market, though, such inclusion is executed in the selective or focused dimensions, marginal, precarious and unstable

A inserção das mulheres na Câmara Municipal de Natal (1988 - 2004)

This work has as objective to reflect about the insertion of the women in the City Council of Natal in the period from 1988 to 2004. We focused our discussion in the context of the politics of quota that has with objective to decrease the frame of inequalities existent between women and men in the politics, besides of to analyze which the determinants responsible for the women's sub-representation. The research still consists of an analysis of the councilor s women profile and how they were seen in that space of power. We analyzed our study object in a gender vision, since this is related intrinsically the social relationships and the relationships of power. The women, for a long time, they were excluded of the participation in the public life, being just seen as mere expectants. This research is informed mainly by studies which discuss the Gender (Scott, 1990), (Perrot, 1988), (Badinter, 1995), (Bruschini, 2002). We also analyzed the power, politics in the vision of Marx (1996), Foucault (1982) and (Arendt, 2001). We tried to analyze the women's presence in the spaces public and private, showing your conflicts and contradictions faced in the society, focalizing the political character of the women's inclusion in the spaces in that are inserted. The instrument of collection of data was the semi-structured questionnaire, descriptive and analytical - critical. The analyses of the interviews show to the sub-representation of women over the years as a determining factor for these women continue in the invisibility. The women were interviewed councillora ex- bounded from 1988 to 2004. The conclusion the one that we arrived is that this sub-representation has as decisive the patriarchal system that prevailed for a long time in our society and still dominates and affects women in all areas of your life. This becomes more serious in the capitalist society in which prevail the interests of those that it stops the produced wealth

Serviço Social Audit Saúde no SUS/RN: projeto ético político profissional e de reforma sanitária

Health policies in Brazil, the decentralization of SUS management responsibilities for the three spheres of government has driven the creation and regulation of the audits of health services in the National Audit Office, this is a trend of neoliberal policies imposed by international bodies like the World Bank and IMF to peripheral countries characterized by productive restructuring and reforming the state focuses on the presence of two competing projects in the area of health: Health Sector Reform Project which is based on the democratic rule of law with the assumption of health as social right and duty of the State in defending the extension of the conquest of rights and democratization of access to health care guaranteed through the public financing strategies and the effective decentralization of decisions pervaded by social control and privatized Health Project which is based on the state minimum, with a reduction in social spending or in partnerships and privatization, stronger nonprofit sector, subject to capitalist interests, is made effective through strategies targeting health policy and refilantropização actions. In this context, the present study is an analysis on the work of social audits of public health in infants from a qualitative and quantitative approach, embodied by the critical method of dialectical Marxist social theory that enabled us to unveil the characterization, the demands, challenges and outline the profile of Social Work in teams inserted audits of SUS in RN, but also provided evidence to demonstrate the prospects and possibilities of this area of activity of social workers. It was also found that through the audit work that the state fulfill its role as bureaucratic and regulator of health services with efficiency, effectiveness and economy. Yet, paradoxically, the audits of SUS may provide a vehicle for enforcing rights and ensuring the fundamental principles contained in the project of health reform, because it can be configured in a space of political struggle as representing a new field of knowledge production that needs to be appropriate for a theoretical critic able to redirect the social interests in favor of the user. From this perspective, it is concluded that the work of social audits of public health in infants despite the social relevance that prints, as they constitute an activity study of reality and its transformation proposition requires a transformative political action guided the discussion Marxist theory holds that the ethical project professional politician of Social Work