Projeto em FPGA de um controlador unificado para correção de fator de potência em retificadores boost bidirecionais monofásicos

The use of Field Programmable Gate Array (FPGA) for development of digital control strategies for power electronics applications has aroused a growing interest of many researchers. This interest is due to the great advantages offered by FPGA, which include: lower design effort, high performance and highly flexible prototyping. This work proposes the development and implementation of an unified one-cycle controller for boost CFP rectifier based on FPGA. This controller can be applied to a total of twelve converters, six inverters and six rectifiers defined by four single phase VSI topologies and three voltage modulation types. The topologies considered in this work are: full-bridge, interleaved full-bridge, half-bridge and interleaved half-bridge. While modulations are classified in bipolar voltage modulation (BVM), unipolar voltage modulation (UVM) and clamped voltage modulation (CVM). The proposed project is developed and prototyped using tools Matlab/Simulink® together with the DSP Builder library provided by Altera®. The proposed controller was validated with simulation and experimental results

Desenvolvimento de um secador spray para obtenção de pós finos de precursores de nióbio

This work presents a spray-dryer designed to oxalate-niobate precursors and suitable for the production of Niobium Carbide. The dryer was intended to produce powders of controlled particle size. First, the precursor is dissolved in water to produce a solution of known concentration and then it is atomized on the spray-dryer to produce the powder. This equipment consists of a 304 stainless steel chamber, 0.48 m x 1.9 m (diameter x length), with a conical shape at the lower portion, which is assembled on a vertical platform. The chamber is heated by three 4 kW electrical resistances. In this process, drying air is heated as it flows inside a serpentine surrounding the chamber, in contrary to more traditional processes in which the hot drying air is used to heat the component. The air enters the chamber at the same temperature of the chamber, thus avoiding adherence of particles on the internal surface. The low speed flow is concurrent, directed from the top to the bottom portion of the chamber. Powders are deposited on a 0.4 m diameter tray, which separates the cylindrical portion from the conical portion of the chamber. The humid air is discharged though a plug placed underneath the collecting tray. A factorial experimental planning was prepared to study the influence of five parameters (concentration, input flow, operation temperature, drying air flow and spray air flow) on the characteristics of the powders produced. Particle size distribution and shape were measured by laser granulometry and scanning electronic microscopy. Then, the powders are submitted to reaction in a CH4 / H2 atmosphere to compare the characteristics of spray-dried powders with powders synthetizided by conventional methods

A grande Argentina: um sonho nacionalista para a construção de uma potência na América Latina

Visa-se analisar a proposta de transformação da Argentina em uma potência econômica e militar hegemônica na América do Sul, levada a cabo por correntes de extrema-direita desse país, entre as duas Guerras Mundiais. Discutem-se os objetivos, conteúdos e fundamentação dessa proposta no contexto do cenário internacional e da conjuntura política argentina.

Funções psicofísicas para área percebida, inferida e relembrada: o efeito da idade

O objetivo deste trabalho foi verificar o efeito da idade no expoente da função-potência nas Condições experimentais Perceptiva, Memória e Inferência. Para cada Condição, as faixas etárias dos sujeitos variaram de 17 a 34 anos (I), 38 a 57 anos (II) e 58 a 77 anos de idade (III). Os sujeitos estimaram áreas dos Estados do Brasil, utilizando o método psicofísico de estimação de magnitude. Os resultados obtidos pelas três Faixas etárias não diferiram para cada Condição experimental, com exceção da Condição Memória (24 horas). A análise entre as Condições experimentais e Faixas etárias evidenciou uma diferença da Condição Perceptiva em relação às demais, não havendo diferenças entre as Condições Memória e Inferência. Os dados apresentados sugerem que no processo de relembrar, não há perda da informação em função da idade.

A Hora e o Nevoeiro: discurso épico, vontade de potência e mal-estar da modernidade no poema Mensagem de Fernando Pessoa

Considering articles written for Fernando Pessoa in 1912 about The new Portuguese poetry , where he already proclaimed the appearance of the Super-Camões, poet that would be able to revolutionize Portuguese literature e, concomitantly, to make resurging from rubble the Portuguese nation; we understand that, decades before the writing of Message, the poet was already armed with a Will of Power , expression of Friedrich Nietzsche that incorporate the idea of resurgence to the man like creator of news values. Fernando Pessoa believed to make his poetical word, the epic, restoring word of the ideas of Messianism and Fifth Empire as the pushing force of the new Portuguese largeness. However, we look for to investigate the conditions of Malaise that surround the universe of the poem and that restrict its capacity of action on the reality in its return, a time that the space destined in modernity to the poet and to his poetry hindered him of a devoted and positive action, We select therefore theorist like Sigmund Freud e Walter Benjamin

Alterações posturais em atletas brasileiros do sexo masculino que participaram de provas de potência muscular em competições internacionais

Os esportes de alto nível determinam padrões corporais que extrapolam barreiras geopolíticas, sociais e culturais. Estas peculiaridades resultam em alterações posturais que estão associadas à eficiência do gesto desportivo, porém, em longo prazo, podem evoluir para processos mórbidos que limitam a prática de atividades físicas regulares. O objetivo da pesquisa foi descrever o perfil postural dos atletas que participam de provas de potência muscular e identificar processos anátomo-cinesiológicos responsáveis pelas principais alterações corporais. A casuística foi composta por 15 atletas do sexo masculino, especializados em provas de potência muscular. O protocolo para coleta de dados foi elaborado com base na proposta de: i) Kendall, para o exame físico e observacional, utilizando simetrógrafo e fio de prumo; ii) Souchard, para a análise postural em cadeia. As informações foram organizadas sob a forma de distribuição de freqüência absoluta e relativa. Os resultados apontaram que: i) o tornozelo em valgo (67%) foi a situação mais comum; ii) a rotação interna da pelve à direita (60%), seguida do lado oposto mais elevado (47%), pode estar relacionada com a corrida em curva que sobrecarrega a estrutura da pelve para a manutenção da velocidade com simultânea mudança de direção em função da força gravitacional; iii) a anteversão de pelve (73%) decorre da retração observada nos músculos flexores do quadril e extensores do joelho; iv) a alteração expressa no item iii contribui para a formação de hiperlordose lombar (73%) e desencadeia mecanismo compensatório de retração da cadeia posterior causando cifose torácica (53%) e cabeça em protrusão (73%). O diagnóstico precoce e a adoção de medidas profiláticas efetivas podem contribuir para o aumento da performance, bem como prevenir a ocorrência de lesões desportivas. Estudos envolvendo intervenção fisioterápica deverão avaliar se há redução dos efeitos crônicos que as alterações posturais decorrentes do treinamento causam ao atleta de alto nível.

Análises estatísticas em redes complexas: propriedades topológicas, críticas e dinâmicas

In this thesis, we address two issues of broad conceptual and practical relevance in the study of complex networks. The first is associated with the topological characterization of networks while the second relates to dynamical processes that occur on top of them. Regarding the first line of study, we initially designed a model for networks growth where preferential attachment includes: (i) connectivity and (ii) homophily (links between sites with similar characteristics are more likely). From this, we observe that the competition between these two aspects leads to a heterogeneous pattern of connections with the topological properties of the network showing quite interesting results. In particular, we emphasize that there is a region where the characteristics of sites play an important role not only for the rate at which they get links, but also for the number of connections which occur between sites with similar and dissimilar characteristics. Finally, we investigate the spread of epidemics on the network topology developed, whereas its dissemination follows the rules of the contact process. Using Monte Carlo simulations, we show that the competition between states (infected/healthy) sites, induces a transition between an active phase (presence of sick) and an inactive (no sick). In this context, we estimate the critical point of the transition phase through the cumulant Binder and ratio between moments of the order parameter. Then, using finite size scaling analysis, we determine the critical exponents associated with this transition

Efeitos da perda de peso induzida pela cirurgia bariátrica sobre a função respiratória

Background: Obesity leads to alteration of lung volumes and capacities due to accumulation of fat in the chest wall and abdomen. Few studies have shown that weight loss induced by surgery improves lung function. Our objective was to evaluate the anthropometric development, pulmonary function, respiratory muscle, strength and endurance after weight loss induced by bariatric surgery. Methods: We evaluated in pre and post operative period variables of weight, BMI, NC, WHR and spirometric and respiratory pressure. Results: 39 subjects were evaluated, with age mean 35.9 ± 10.9 years, predominantly by women (76.3%). The weight mean decreased from 124.8 ± 17.5 kg to 88.8 ± 14.28 kg in post operative. The mean BMI ranged from 47,9 ± 5,6 Kg/m² to 34,3 ± 4,75 Kg/m². There was a significant increase in FVC from 3,63 ± 0,94 to 4,01±1,03, FEV1 from 3,03 ± 0,72 to 3,39 ± 0,85, FEF 25-75% from 3,41 ± 0,72 to 3,82 ± 0,94, PEF from 6,56 ± 1,47 to 7,81 ± 1,69, ERV from 0,35 ± 0,39 to 0,66 ± 0,38, MVV ranged from 103,43 ± 22,21 to 137,27 ± 29,84, all of them to p<0,01. The MIP and MEP showed no significant difference in pre and post operative. It was noted that for every centimeter reduced in neck circumference, an increase of 0.06 in FVC and 5.98 in MVV is observed. This is also observed in weight and BMI. Conclusion: We conclude that weight loss induced by bariatric surgery in obese provides a significant improvement in lung function and reduction of fat around the neck is more important in the generation of lung volume than the reduction of BMI

Um método primal-dual aplicado na resolução do problema de fluxo de potência ótimo

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Fluxo de potência ótimo reativo via método da função lagrangiana barreira modificada

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Determinação da solução ótima do problema de fluxo de potência ótimo via análise de sensibilidade

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Edentulismo funcional e seus fatores de risco em adultos

The purpose of this study was to investigate the risk factors to the functional edentulism in adults aged 35 a 44 years old of Natal-RN, 278 adults took part in the study. They were all selected from a previous dental loss prevalence study thus being complemented by an active research. The study was a case-control based and data collection was made though a survey as well as with a clinical examination. The cases were identified through individuals with 20 or more teeth. Age and gender were used as variables of pairing off. The data was analyzed through chi-square, significant level of 95% to the checking of its force associations. The independent variables were grouped in three levels. The first one, more macro, is related to the region where the individual lives, which was also related to the second level, the family-based one, linked with a third level, at this low socio-economical level, where the domiciliary density was favorable, living in capital cities, regions with prime sanitary condicitions, with predominant possibility of accessing the public dental service, but in despite of this, only looking for this service when tooth ache is felt, where preferentially an aid dressing treatment is executed in detriment of preventive procedures. From all the samples, less than 25% of the individuals make use of tobacco and alcoholic beverages for quite a number of years. There was an association of functional edentulism with all the studied variables in a regional method. In the family-based with Critério Brasil (OR=4,45) and monthly wages (OR=9,62) and to an to an individual level, the associations took place with the current use of kind of attendance (OR=1,78), looks for dressing treatment (OR=2,51), does not look for preventive treatment (OR=3,31), pain as the main cause of demand (OR=1,92), previous treatment as the demanding reason for dental service (OR+0,28), interval of the last visit to the dental service (OR=1,35) and when advise was received (OR=1,66). It was noticed from the results that the functional edentulism is much more expressive in those families which live in environments with precarious social economical sanitary conditions. Such conditions seem to have a direct influence upon the family social economical conditions which are also shown in detriment to functional edentulism. In the same way, the collection of variants influence the social economical conditions of the individual, as well as the kind of dental service searched by them, the reason of the search and the interval of the last visit to the dental service were strong determiners to the functional edentulism. Beyond that, individual habits like the use of tobacco and its frequency on its previous use influenced in a significant way the existence of functional edentulism in the studied population

A Perda Auditiva Induzida pelo Ruído (PAIR) na formação odontológica: conhecimentos e níveis de exposição

The rationalization of work in the Dentistry has been taking the professional to work for ways and systems based in the ergonomics, turning their work efficient and less tiring. Since their academic formation, the dentists surgeons are concerned with the high productivity in clinic and with the final result of the work, neglecting the way as it is executed, which reduce their work capacity and exhibits them to occupational diseases that could be minimized and/or forewarned. This research had as the main objective to investigate the knowledge of the Dentistry academics of Rio Grande do Norte Federal University concerning the Noise-induced Hearing Loss (NIHL), relating them at the noise levels that they are exposed, as well as to the preventive measures taken during the clinical activities. Was observed that 95% of the individuals know that the dentist surgeon is a professional in risk for NIHL. Among the causes of NIHL, the one that obtained the largest frequency citation was the high-speed handpieces, reminded by 92,4% of the academics. Among the students which enumerated protective measures for NIHL, 92% mentioned the use of the ear plugs, although 97% of the researched have told do not use any kind of preventive measure related to the noise. Was also observed that 96% of the academics notice the noise during the clinical attendance, what inconvenience 28,1% of them. Related the noise levels, the high-speed handpieces of the academics presented a medium value of 80,5 dB varying from 72,3 to 88,3 dB. The average of the ambient noise observed at the Integrated Clinic was about 74,8 dB. In spite of the noise levels in this research were observed below the established limits of tolerance by the legislation, they can provoke damages to the Dentistry professionals' health, or that suggests the need of an intervention and use of immediate preventive measures able to generate a healthy atmosphere of work and less risky

Resposta celular Th1 /Th2 na doença periodontal experimental, em ratos: um estudo imuno-histoquímico

Host response plays a major role in the pathogenesis of periodontal disease. Mediators such as inflammatory cytokines which are secreted during the immune response to bacterial challenges have ambiguous functions that may or may not lead to protection of the attacked tissue. In this context, experimental evidence suggests that T-helper 1 (Th-1) and T-helper 2 (Th-2) mediated responses are potentially important during the disease process. The aims of this study therefore were to further clarify the role played by Th2 cells during different time points of the active phase of periodontal disease, as well as, to investigate whether there was any evidence of a Th1 response in the periodontal disease microenvironment. Experimental periodontitis was induced in 30 Wistar male rats by placing cotton ligatures around the mandibular first molars. The rats were then randomly divided into two groups. Group1 (G1=15) and Group 2 (G2=15). In G1 the ligatures were maintained for 2 days, whereas in G2 the ligatures were left for 15 days, a time point that corresponds to the advanced stage of periodontal disease The contra-lateral teeth served as controls (no ligatures). Immunohistochemical investigation for the presence in gingival tissue of Th2 specific transcription factor (GATA3) and the subunit of the IFN-γ receptor was carried out after the disease induction period. Light microscopy analysis revealed a decrease in the expression of GATA-3 as bone loss progressed. On the other hand, although IFN-γ R1 was detected at an early stage of the active phase of disease its expression remained unaltered during the remaining period of the study. These results indicate that the Th2 response have a protective role during the pathogenesis of periodontal disease and that the progression of the periodontal disease is related with the unbalance of the responses Th1/Th2

Estudo comportamental, hormonal e histopatológico de animais com perda de peso progressina (SEP) e da variável peso associada a uma nova classificação ontogenética em Callithrix jacchus

The use of non-human primates in scientific research has contributed significantly to the biomedical area and, in the case of Callithrix jacchus, has provided important evidence on physiological mechanisms that help explain its biology, making the species a valuable experimental model in different pathologies. However, raising non-human primates in captivity for long periods of time is accompanied by behavioral disorders and chronic diseases, as well as progressive weight loss in most of the animals. The Primatology Center of the Universidade Federal do Rio Grande do Norte (UFRN) has housed a colony of C. jacchus for nearly 30 years and during this period these animals have been weighed systematically to detect possible alterations in their clinical conditions. This procedure has generated a volume of data on the weight of animals at different age ranges. These data are of great importance in the study of this variable from different perspectives. Accordingly, this paper presents three studies using weight data collected over 15 years (1985-2000) as a way of verifying the health status and development of the animals. The first study produced the first article, which describes the histopathological findings of animals with probable diagnosis of permanent wasting marmoset syndrome (WMS). All the animals were carriers of trematode parasites (Platynosomum spp) and had obstruction in the hepatobiliary system; it is suggested that this agent is one of the etiological factors of the syndrome. In the second article, the analysis focused on comparing environmental profile and cortisol levels between the animals with normal weight curve evolution and those with WMS. We observed a marked decrease in locomotion, increased use of lower cage extracts and hypocortisolemia. The latter is likely associated to an adaptation of the mechanisms that make up the hypothalamus-hypophysis-adrenal axis, as observed in other mammals under conditions of chronic malnutrition. Finally, in the third study, the animals with weight alterations were excluded from the sample and, using computational tools (K-means and SOM) in a non-supervised way, we suggest found new ontogenetic development classes for C. jacchus. These were redimensioned from five to eight classes: infant I, infant II, infant III, juvenile I, juvenile II, sub-adult, young adult and elderly adult, in order to provide a more suitable classification for more detailed studies that require better control over the animal development