Caracterização de circuitos planares de micro-ondas pelo método iterativo das ondas

The planar circuits are structures that increasingly attracting the attention of researchers, due the good performance and capacity to integrate with other devices, in the prototyping of systems for transmitting and receiving signals in the microwave range. In this context, the study and development of new techniques for analysis of these devices have significantly contributed in the design of structures with excellent performance and high reliability. In this work, the full-wave method based on the concept of electromagnetic waves and the principle of reflection and transmission of waves at an interface, Wave Concept Iterative Procedure (WCIP), or iterative method of waves is described as a tool with high precision study microwave planar circuits. The proposed method is applied to the characterization of planar filters, microstrip antennas and frequency selective surfaces. Prototype devices were built and the experimental results confirmed the proposed mathematical model. The results were also compared with simulated results by Ansoft HFSS, observing a good agreement between them.

Estimação de Fasores para Proteção de Sistemas Elétricos Baseada em Mínimos Quadrados e Morfologia Matemática

This work proposes a new technique for phasor estimation applied in microprocessor numerical relays for distance protection of transmission lines, based on the recursive least squares method and called least squares modified random walking. The phasor estimation methods have compromised their performance, mainly due to the DC exponential decaying component present in fault currents. In order to reduce the influence of the DC component, a Morphological Filter (FM) was added to the method of least squares and previously applied to the process of phasor estimation. The presented method is implemented in MATLABr and its performance is compared to one-cycle Fourier technique and conventional phasor estimation, which was also based on least squares algorithm. The methods based on least squares technique used for comparison with the proposed method were: forgetting factor recursive, covariance resetting and random walking. The techniques performance analysis were carried out by means of signals synthetic and signals provided of simulations on the Alternative Transient Program (ATP). When compared to other phasor estimation methods, the proposed method showed satisfactory results, when it comes to the estimation speed, the steady state oscillation and the overshoot. Then, the presented method performance was analyzed by means of variations in the fault parameters (resistance, distance, angle of incidence and type of fault). Through this study, the results did not showed significant variations in method performance. Besides, the apparent impedance trajectory and estimated distance of the fault were analysed, and the presented method showed better results in comparison to one-cycle Fourier algorithm

Democratização do acesso ao ensino superior: os cursos de graduação à distância na UFRN

This thesis pursuits to contextualize the theoretical debate between the implementation of public education policy of the Federal Government focused in a distance learning and legal foundations for its enforcement, in order to raise questions and comments on the topic in question. Its importance is back to provide scientific input and can offer to the academy, particularly in the UFRN, and elements of society to question and rethink the complex relationship between the socio-economic and geographic access to higher education. It consists of a descriptive study on the institutionalization of distance education in UFRN as a mechanism for expanding access to higher education, for both, the research seeks to understand if the distance undergraduate courses offered by the UAB system and implemented at UFRN, promote expanding access to higher education, as it is during implementation that the rules, routines and social processes are converted from intentions to action. The discussion of this study lasted between two opposing views of Implementation models: Top-down and Bottom-up. It is worth noting that the documents PNE, PDE and programs and UAB MEETING reflect positively in improving the educational level of the population of the country It is a qualitative study, using the means Bibliographic, Document and Field Study, where they were performed 04 (four) in 2010 interviews with the management framework SEDIS / UAB in UFRN. The data were analyzed and addressed through techniques: Document Analysis and Content Analysis. The results show that the process of implementation of distance education at UFRN is in progress. According to our results, the research objective is achieved, but there was a need to rethink the conditions of the infrastructure of poles, the structure of the academic calendar, the management of the SEDIS UFRN, regarding the expansion of existing vacancies and the supply of new courses by the need for a redesign as the Secretariat's ability to hold the offerings of undergraduate courses offered by the Federal Government to be implemented in the institution. It was also found that levels of evasion still presents a challenge to the teaching model. Given the context, we concluded that the greatest contribution of UAB and consequently UFRN by distance learning for undergraduate courses (Bachelor in Mathematics, Physics, Chemistry, Geography and Biological Sciences, beyond the bachelor's degrees in Business and Public Administration ) is related to increasing the number of vacancies and accessibility of a population that was previously deprived of access to university

Adição de cascalho de perfuração da bacia potiguar em argilas para uso em materiais cerâmicos: influência da concentração e temperatura de queima.

One of waste produced on large scale during the well drilling is the gravel drilling. There are techniques for the treatment of the same, but there isn t consensus on what are the best in terms of economic and environmental. One alternative for disposal of this waste and objective of this paper is the incorporation and immobilization of gravel clay matrix to assess their technological properties. The Raw Materials used were characterized by the following techniques: Chemical Analysis by X-ray fluorescence (XRF), mineralogical analysis by X-ray Diffraction (XRD), Grain Size Analysis (FA) and Thermal Analysis by Thermogravimetry (TG) and thermodiferential (DTA). After characterizing, samples were formulated in the following percentages: 0, 5, 10, 15, 25, 50, 75, 100% (weight) of gravel drilling, then the pieces were pressed, dried (110 ° C) and sintered at temperatures of 850, 950 and 1050 ° C. After sintering, samples were tested for water absorption, linear shrinkage, flexural strength, porosity, density, XRD and test color. The results concluded that the incorporation of gravel drilling is a viable possibility for solid masonry bricks and ceramic blocks manufacture at concentrations and firing temperature described here. Residue incorporation reduces an environmental problem, the cost of raw materials for manufacture of ceramic products

Novo método para estimativa do gradiente de fratura para poços de petróleo

The development of oil wells drilling requires additional cares mainly if the drilling is in offshore ultra deep water with low overburden pressure gradients which cause low fracture gradients and, consequently, difficult the well drilling by the reduction of the operational window. To minimize, in the well planning phases, the difficulties faced by the drilling in those sceneries, indirect models are used to estimate fracture gradient that foresees approximate values for leakoff tests. These models generate curves of geopressures that allow detailed analysis of the pressure behavior for the whole well. Most of these models are based on the Terzaghi equation, just differentiating in the determination of the values of rock tension coefficient. This work proposes an alternative method for prediction of fracture pressure gradient based on a geometric correlation that relates the pressure gradients proportionally for a given depth and extrapolates it for the whole well depth, meaning that theses parameters vary in a fixed proportion. The model is based on the application of analytical proportion segments corresponding to the differential pressure related to the rock tension. The study shows that the proposed analytical proportion segments reaches values of fracture gradient with good agreement with those available for leakoff tests in the field area. The obtained results were compared with twelve different indirect models for fracture pressure gradient prediction based on the compacting effect. For this, a software was developed using Matlab language. The comparison was also made varying the water depth from zero (onshore wellbores) to 1500 meters. The leakoff tests are also used to compare the different methods including the one proposed in this work. The presented work gives good results for error analysis compared to other methods and, due to its simplicity, justify its possible application

Violência institucional no âmbito da saúde reprodutiva : a percepção de mulheres usuárias do SUS, na cidade de Natal/RN

Institutional violence ranges from the most widespread lack of access to the poor quality of services provided. It includes abuses committed by virtue of the unequal power between patients and professionals within institutions. The aim of this study was to analyze the perception of women with regard to this type of violence, in the services offered at a reproductive health facility belonging to the National Health System (SUS) in Natal, Brazil. Interdisciplinary perspective is important, in that it provides interaction and complementarity between various disciplines, favoring, in an integrated way, a thematic approach in research activities, teaching and extension, involving professionals, students and researchers in medicine, social services, psychology, nursing, anthropology and physical therapy. A quantitative/qualitative approach was used, involving a sample of 401 women, as part of a transversal observational study. In the qualitative stage, which consisted of participatory observation and semi-structured interviews, we used an intentional sample of 10 individuals. The data were analyzed using logistic regression techniques, correspondence analysis and categorical thematic content analysis, showing that the 2 questions that investigated directly the perception of institutional violence obtained affirmative response frequencies of 28.2% and 31.8%, respectively. In regard to data collected in a field diary related to participatory observation, the main complaints referred to the health providerpatient relation, translated into dissatisfaction with the interpersonal relationship and with the resolution of the specific demand that required care. From content analysis, we classified 4 categories: Access; Information; Health professionalpatient relation; and Respect/dignity. We identified 6 subcategories: Impossibility of choice; Repressed demand; Communication difficulty; Asymmetric interpersonal relations; Privacy/confidentiality; Disrespect. We concluded, therefore, that the data presented show that in the reproductive health care programs, there are indicators of institutional violence. However, it is difficult to approach this phenomenon, mainly because of the power relations involved in the patient-health care provider interaction, resulting from unawareness that determinate situations violate sexual and reproductive rights. This can be explained by sociostructural questions that reveal marked inequalities, ratified by issues related to violation of the rights of National Health System (SUS) patients

Sistemas de informação geográfica e análise espacial de dados como ferramentas para determinação de agregação espacial de doenças: a hanseníase como modelo

This work demonstrates the importance of using tools used in geographic information systems (GIS) and spatial data analysis (SDA) for the study of infectious diseases. Analysis methods were used to describe more fully the spatial distribution of a particular disease by incorporating the geographical element in the analysis. In Chapter 1, we report the historical evolution of these techniques in the field of human health and use Hansen s disease (leprosy) in Rio Grande do Norte as an example. In Chapter 2, we introduced a few basic theoretical concepts on the methodology and classified the types of spatial data commonly treated. Chapters 3 and 4 defined and demonstrated the use of the two most important techniques for analysis of health data, which are data point processes and data area. We modelled the case distribution of Hansen s disease in the city of Mossoró - RN. In the analysis, we used R scripts and made available routines and analitical procedures developed by the author. This approach can be easily used by researchers in several areas. As practical results, major risk areas in Mossoró leprosy were detected, and its association with the socioeconomic profile of the population at risk was found. Moreover, it is clearly shown that his approach could be of great help to be used continuously in data analysis and processing, allowing the development of new strategies to work might increase the use of such techniques in data analysis in health care

Análise da influência da qualidade em um ciclo de serviços na satisfação do cliente: estudo de caso em uma instituição de ensino.

With the increasing offer of education services in Brazil, it is necessary to evaluate the quality of service in education, especially in those institutions for vocational education which have a greater interaction with the labor market, in order to form qualified professionals and meet the growing demand that the country has today[A1] . In Brazil, the evaluation of the quality of library services has influenced the assessment of educational institutions and in this context, there needs to be a process to monitor the quality of services provided by libraries. However, the service is not done in a single moment and thus to a more detailed assessment it needs to be measured and evaluated each different time the customer uses it. Therefore, the aim of this work consists in measuring the quality in every moment of truth of a cycle of library services to assess which are the most relevant moments in the client's perspective at the library of the Federal Institute of Education, Science and Technology of Rio Grande do Norte (IFRN) Campus João Câmara in building the overall quality of service. In the literature review, internal secondary sources were used, from the database of the institution studied, and also external sources, through literature in books, articles, dissertations, theses and journals on compost quality, service quality, cycle services, measuring quality, satisfaction, teaching activities, and on library services specifically. We applied a questionnaire to students in the library based on models of quality measurement SERVPERF and SERVQUAL and its variations such as SERVQUAL pondered and SERVPERF pondered . Through analysis based on concepts of reliability and validity of measuring instruments, it was found that the SERVPERF model is the instrument that most closely matches the dimensions of quality assessed in the library with customer satisfaction measured by the questionnaire. From there, the search results as measured by statistical techniques of analysis, indicated that the initial and final moments of truth of the cycle of service quality had the greatest influence on overall customer satisfaction with the library service

Desacoplamento de um gerador síncrono através de um controle adaptativo por modelo de referência baseado em funções de Base radial

An alternative nonlinear technique for decoupling and control is presented. This technique is based on a RBF (Radial Basis Functions) neural network and it is applied to the synchronous generator model. The synchronous generator is a coupled system, in other words, a change at one input variable of the system, changes more than one output. The RBF network will perform the decoupling, separating the control of the following outputs variables: the load angle and flux linkage in the field winding. This technique does not require knowledge of the system parameters and, due the nature of radial basis functions, it shows itself stable to parametric uncertainties, disturbances and simpler when it is applied in control. The RBF decoupler is designed in this work for decouple a nonlinear MIMO system with two inputs and two outputs. The weights between hidden and output layer are modified online, using an adaptive law in real time. The adaptive law is developed by Lyapunov s Method. A decoupling adaptive controller uses the errors between system outputs and model outputs, and filtered outputs of the system to produce control signals. The RBF network forces each outputs of generator to behave like reference model. When the RBF approaches adequately control signals, the system decoupling is achieved. A mathematical proof and analysis are showed. Simulations are presented to show the performance and robustness of the RBF network

Análise da adição de resíduo oriundo do tratamento de esgotos em massa cerâmica utilizada para fabricação de telhas

Sludge of Wastewater Treatment Plants (WTPs) disposal is a problem for any municipality, for this reason the amount of sludge production is now a key issue in selecting treatment methods. It is necessary to investigate new applications for this waste type, due to the restrictions imposed by the environmental organs. The raw materials used in the Red Ceramic, are generally very heterogeneous, for this reason, such materials can tolerate the presence of different types of wastes. In Rio Grande do Norte, the roof tiles production corresponds to 60,61% from the total of ceramic units produced. Due to the importance of the ceramic industry of roof tiles for the state, allied to the environmental problem of the sludge disposal, this work had for objective to verify the possibility of the incorporation of sewage sludge in ceramic body used for production of roof tiles. In the research, sludge originating from drying beds of WTP of the Central Campus from UFRN and clays originating from a ceramic industry from Goianinha/RN were used. The raw materials were characterized by techniques of: analysis of particles distribution by diffraction to laser; real density; consistence limits; chemical analysis by X-ray fluorescence; mineralogical analysis by X-ray diffraction; organic matter; and solids content. Five batches of roof tiles were manufactured in the approximate dosages of 2%, 4%, 6%, 8% and 10%. To evaluate the properties of each final product, tests of water absorption, impermeability, bending strength, leachability and solubility were accomplished. The roof tiles manufactured with sludge presented characteristics similar to the roof tiles without sludge in relation to the environmental risk. The results showed that it is possible to use approximately up to 4% of sludge in ceramic bodies for production of roof tiles. However, it is observed that the high amount of organic matter (71%) present in the sludge is shown as factor that limits the sludge incorporation in ceramic bodies, worsening the quality of the roof tiles. It is necessary the use of mixtures of different raw materials under point of view of the granulometry and of the other chemical and mineralogical properties for the obtaining of a satisfactory mass to the production of ceramic roof tiles

Síntese, caracterização e estudo das propriedades magnéticas de ortoferritas de lantânio dopadas com manganês

Orthoferrites AFeO3 (A = rare earth) are an important class of perovskite oxides that exhibit weak ferromagnetism. These materials find numerous applications as chemical sensors, cathodes for fuel cells and catalysis, which make them interesting from the standpoint of science and technology. Their structural, electrical and magnetic properties are dependent on many factors such as the preparation method, heat treatment conditions, chemical composition and replacement of cations in sites A and/or B. In this paper, LaFe1-xMnxO3 (0 ≤ x ≤ 1) orthoferrites-type was prepared by Pechini method and Microwave-assisted combustion reaction in order to evaluate the influence of synthesis route on the formation of oxide, as well as the effect of parcial replacement of iron by manganese and heat treatment on the magnetic properties. The precursor powders were calcined at 700°C, 900°C, 1100°C and 1300°C for 4 hours and they were characterized by the techniques: Thermogravimetric analysis (TGA), X ray diffraction (XRD), Refinement by Rietveld method, Scanning electron microscopy (SEM), Reduction temperature programmed (RTP) and Magnetic hysteresis measurements performed at room temperature. According to the XRD patterns, the formation of perovskite phase with orthorhombic structure was observed for the systems where 0 ≤ x ≤ 0.5 and rhombohedral for x = 1. The results also showed a decrease of lattice parameters with the parcial replacement of iron by manganese and consequently a reduction in cell volume. The hysteresis curves exhibited weak ferromagnetism for the systems prepared by both synthesis methods. However, a dependence of magnetization as a function of dopant content was observed for samples produced by Pechini method. As for the systems prepared by combustion reaction, it was found that the secondary phases exert a strong influence on the magnetic behavior

Democratização do acesso ao ensino superior: os cursos de graduação à distância na UFRN

This thesis pursuits to contextualize the theoretical debate between the implementation of public education policy of the Federal Government focused in a distance learning and legal foundations for its enforcement, in order to raise questions and comments on the topic in question. Its importance is back to provide scientific input and can offer to the academy, particularly in the UFRN, and elements of society to question and rethink the complex relationship between the socio-economic and geographic access to higher education. It consists of a descriptive study on the institutionalization of distance education in UFRN as a mechanism for expanding access to higher education, for both, the research seeks to understand if the distance undergraduate courses offered by the UAB system and implemented at UFRN, promote expanding access to higher education, as it is during implementation that the rules, routines and social processes are converted from intentions to action. The discussion of this study lasted between two opposing views of Implementation models: Top-down and Bottom-up. It is worth noting that the documents PNE, PDE and programs and UAB MEETING reflect positively in improving the educational level of the population of the country It is a qualitative study, using the means Bibliographic, Document and Field Study, where they were performed 04 (four) in 2010 interviews with the management framework SEDIS / UAB in UFRN. The data were analyzed and addressed through techniques: Document Analysis and Content Analysis. The results show that the process of implementation of distance education at UFRN is in progress. According to our results, the research objective is achieved, but there was a need to rethink the conditions of the infrastructure of poles, the structure of the academic calendar, the management of the SEDIS UFRN, regarding the expansion of existing vacancies and the supply of new courses by the need for a redesign as the Secretariat's ability to hold the offerings of undergraduate courses offered by the Federal Government to be implemented in the institution. It was also found that levels of evasion still presents a challenge to the teaching model. Given the context, we concluded that the greatest contribution of UAB and consequently UFRN by distance learning for undergraduate courses (Bachelor in Mathematics, Physics, Chemistry, Geography and Biological Sciences, beyond the bachelor's degrees in Business and Public Administration ) is related to increasing the number of vacancies and accessibility of a population that was previously deprived of access to university

Adição de cascalho de perfuração da bacia potiguar em argilas para uso em materiais cerâmicos: influência da concentração e temperatura de queima.

One of waste produced on large scale during the well drilling is the gravel drilling. There are techniques for the treatment of the same, but there isn t consensus on what are the best in terms of economic and environmental. One alternative for disposal of this waste and objective of this paper is the incorporation and immobilization of gravel clay matrix to assess their technological properties. The Raw Materials used were characterized by the following techniques: Chemical Analysis by X-ray fluorescence (XRF), mineralogical analysis by X-ray Diffraction (XRD), Grain Size Analysis (FA) and Thermal Analysis by Thermogravimetry (TG) and thermodiferential (DTA). After characterizing, samples were formulated in the following percentages: 0, 5, 10, 15, 25, 50, 75, 100% (weight) of gravel drilling, then the pieces were pressed, dried (110 ° C) and sintered at temperatures of 850, 950 and 1050 ° C. After sintering, samples were tested for water absorption, linear shrinkage, flexural strength, porosity, density, XRD and test color. The results concluded that the incorporation of gravel drilling is a viable possibility for solid masonry bricks and ceramic blocks manufacture at concentrations and firing temperature described here. Residue incorporation reduces an environmental problem, the cost of raw materials for manufacture of ceramic products

Novo método para estimativa do gradiente de fratura para poços de petróleo

The development of oil wells drilling requires additional cares mainly if the drilling is in offshore ultra deep water with low overburden pressure gradients which cause low fracture gradients and, consequently, difficult the well drilling by the reduction of the operational window. To minimize, in the well planning phases, the difficulties faced by the drilling in those sceneries, indirect models are used to estimate fracture gradient that foresees approximate values for leakoff tests. These models generate curves of geopressures that allow detailed analysis of the pressure behavior for the whole well. Most of these models are based on the Terzaghi equation, just differentiating in the determination of the values of rock tension coefficient. This work proposes an alternative method for prediction of fracture pressure gradient based on a geometric correlation that relates the pressure gradients proportionally for a given depth and extrapolates it for the whole well depth, meaning that theses parameters vary in a fixed proportion. The model is based on the application of analytical proportion segments corresponding to the differential pressure related to the rock tension. The study shows that the proposed analytical proportion segments reaches values of fracture gradient with good agreement with those available for leakoff tests in the field area. The obtained results were compared with twelve different indirect models for fracture pressure gradient prediction based on the compacting effect. For this, a software was developed using Matlab language. The comparison was also made varying the water depth from zero (onshore wellbores) to 1500 meters. The leakoff tests are also used to compare the different methods including the one proposed in this work. The presented work gives good results for error analysis compared to other methods and, due to its simplicity, justify its possible application