O olhar da criança sobre a brincadeira nos anos iniciais do ensino fundamental

Universidade Federal do Rio Grande do Norte

Implementação experimental de filtro ativo paralelo de potência com aplicação a gerador de indução trifásico

This work describes the experimental implementation of a shunt active power filter applied to a three-phase induction generator. The control strategy of active filter turned to the excitation control of the machine and to decrease the harmonics in the generator output current. Involved the implementation of a digital PWM switching, and was made a comparison of two techniques for obtaining the reference currents. The first technique is based on the synchronous dq reference method and the second on the theory of instantaneous power. The comparison is performed via simulation and experimental results. To obtain the experimental results, was mounted a bench trial and the control and communications needed were implemented using DSP - MS320F2812. The simulation results and experimental data proved the efficiency of the filter to apply, highlighting the technique of instantaneous power

Metalização mecânica de ZrO2 com Ti para brasagem ZrO2/Aço com ligas de adição sem metal ativo

Metal/ceramic interfaces using zirconia have dominated the industrial applications in the last decade, due to the high mechanical strength and fracture toughness of zirconia, especially at temperatures below 300 ºC. Also noteworthy is the good ionic conductivity in high temperatures of this component. In this work joining between ZrO2 Y-TZP and ZrO2 Mg-PSZ with austenitic stainless steel was studied. These joints were brazed at high-vacuum after mechanical metallization with Ti using filler alloys composed by Ag-Cu and Ag-Cu-Ni. The influence of the metallization, and the affinity between the different groups (ceramic / filler alloys) was evaluated, in order to achieve strong metal/ceramic joints. Evaluation of joints and interfaces, also the characterization of base materials was implemented using various techniques, such as: x-ray diffraction, leak test, three-point flexural test and scanning electron microscopy with chemical analysis. The microstructural analysis revealed physical and chemical bonds in the metal/ceramic interfaces, providing superior leak proof joints and stress cracking, in order to a good joint in all brazed samples. Precipitation zones and reaction layers with eutetic characteristics were observed between the steel and the filler metal

O trabalho como princípio educativo: algumas reflexões

Após algumas reflexões sobre o conceito de trabalho e formação, este artigo aborda algumas orientações, ou princípios, que podem contribuir para a organização de programas de formação de adultos. Ao trabalhar em programas de formação dessa natureza, devemos ter em mente que trabalhamos com indivíduos que já possuem conhecimentos elaborados, experiências práticas e vivências que devem ser consideradas como ponto de partida. Assim, devemos considerar que a aprendizagem acontece ao longo da vida, e que um curso é apenas parte do percurso de aprendizagem. Outro aspecto importante é que programas de formação para adultos, especialmente aqueles desenvolvidos em situação de trabalho, devem ter sentido para aqueles que irão participar. Os participantes devem, portanto, aderir voluntariamente à proposta; caso contrário, ela poderá ser entendida apenas como algo imposto, e não como um ganho profissional efetivo. Nas situações de formação em situações de trabalho, é também fundamental que os programas sejam elaborados a partir de um apurado conhecimento da realidade daqueles que irão participar. Avaliar e preservar a memória do que foi realizado evita que ocorram eternos recomeços. Por fim, é fundamental que os programas de formação contem também com um programa de apoio aos participantes, de tal forma que eles se sintam mais seguros no trilhar os caminhos das mudanças, quando retornarem aos seus respectivos espaços de trabalho.

Uma abordagem histórica para o ensino do princípio da inércia

Placed in the field of Didactic of Science, this paper proposes an approach to the introduction of the History of Science in science education, at high school level. It was designed and implemented a series of activities regarding the history of the Principle of Inertia. The aim of this approach was to give more meaning to scientific education, while opening new avenues for a better understanding of the processes of construction of scientific knowledge. The preparation of the activities involved a study of the historical development of the concept of motion, from the Aristotelian physics through physical movement concepts at medieval period, from Galileo, Gassendi, Descartes, until the first law of Newton. The strategy of teaching was applied to three classes of high school (night period) of a state public school at the city of Natal (RN). The results indicated the difficulty of overcoming alternative conceptions about movement by students. Nevertheless, we consider that the implementation of this strategy of teaching both represented gains for the learning of students, and contributed to the resizing of pedagogical practices of the teacher-researcher

O princípio metafísico da poética de Aristóteles

Aristotle's definition of tragedy indicates a metaphysical project insinuated by a notion of kátharsis. The reconstruction of Aristotle's method of definition is inspired in the concepts of enérgeia and dýnamis taken from Physics, understanding cause as substance. The Doctrine of the Four Causes is the theoretical basis of the definition of tragedy, placing tragedy in the genre of imitation and distinguishing its species: language (material cause), noble and complete action (formal cause), actors (efficient cause) and kátharsis (temporarily identified with the final cause). Nevertheless, there is no final cause in the definition of tragedy. The kátharsis of passions is experienced by the spectator when he witnesses tragedy, which is the imitation of a noble action, executed by actors and not narrated. Aristotle justifies hid proposition in favor of mimesis by assuming that imitation is natural to man since infancy and the view of objects allows whoever contemplates them to identify and learn the originals. As a metaphysical principle, kátharsis is projected to beyond definition of tragedy, where it is manifested cathartically, in the spectator. Research about the spectator brings one back to the definition of tragedy, where the imitation is an imperfect copy which evokes in the spectator the presence of the originals of the imitated sentiments, thus realizing the kátharsis of these emotions. In this way kátharsis reveals itself as selfknowledge and approach of divine truth and perfections.

Influência da fadiga no comportamento neuromuscular do quadríceps femoral, após reconstrução do ligamento cruzado anterior

Muscle fatigue is a phenomenon that promotes physiological and biomechanical disorders and their changes in healthy subjects have been widely studied and have significant importance for care in preventing injuries, but we do not have many information about its effects in patients after ACL reconstruction. Thus, this study is to analyze the effects of fatigue on neuromuscular behavior of quadriceps after ACL reconstruction. To reach this objective, participants were forty men, twenty healthy (26,90 ± 6,29 years) and twenty after ACL reconstruction (29,75 ± 7,01 years) with a graft of semitendinosus and gracilis tendons, between four to six months after surgery. At first, there was an assessment of joint position sense (JPS) at the isokinetic dynamometer at a speed of 5°/s and target angle of 45° to analyze the absolute error of JPS. Next, we applied the a muscle fatigue protocol, running 100 repetitions of isokinetic knee flexion-extension at 90°/s. Concurrently with this protocol, there was the assessment of muscle performance, as the peak torque (PT) and fatigue index, and electromyographic activity (RMS and median frequency). Finally, we repeated the assessment of JPS. The statistical analysis showed that patients after ACL reconstruction have, even under normal conditions, the amended JPS compared with healthy subjects and that after fatigue, both have disturbances in the JPS, but this alteration is significantly exacerbated in patients after ACL reconstruction. About muscle performance, we could notice that these patients have a lower PT, although there are no differences between the dynamometric and EMG fatigue index. These findings show the necessity about the cares of pacients with ACL reconstruction in respect of the risks of articulate instability and overload in ligamentar graft

Princípio da Indução Matemática no Ensino Médio

We developed this dissertation aiming its in the process of teaching and learning of the Principle of Mathematical Induction and we set our efforts so that the students of the first year of the high school can assimilate the content having the knowledge seen in the basic education as foreknowledge. With this, we seek to awake in the student the interest on proofs, showing how much it s needed in examples that involve contents that he is already seen

O princípio da precaução e a saúde no trabalho

O princípio da precaução (PP) é uma diretriz em saúde que vem ganhando relevo nos últimos 20 anos. Seu propósito é orientar medidas nas situações em que o conhecimento científico está ainda incompleto, denotando a incerteza. As condições de economia de mercado estimulam o uso de produtos e processos inovadores, dependentes do desenvolvimento científico e das novas descobertas em curso. Suas implicações para a saúde nem sempre estão inteiramente avaliadas, expondo a população trabalhadora às incertezas. O exame da literatura mostra que o uso do PP, embora sob consenso dos órgãos reguladores em diferentes países, ainda é objeto de intenso debate na comunidade científica. em coerência com os propósitos básicos, a proteção do meio ambiente conta com milhares de citações do seu emprego, em contraste com as poucas recomendações de uso para as exposições ocupacionais. Entre estas, o PP vem sendo entendido como pouco adequado ao âmbito dos especialistas e mais indicado à proteção de populações vulneráveis. Investigações históricas mostram que a noção de precaução foi quase sempre usada em sentido inverso, fazendo-se uso da dúvida para conter as possíveis melhorias de proteção no trabalho. Conclui-se que o uso do PP depende do pressuposto da incerteza científica, caracterizada pela noção de risco, em detrimento do determinismo da causa, condição ainda não superada nas relações de trabalho.

Evolução da terminoliga princípio contábil baseada na Escola Norte-Americana

This research has as objective of study the evolution of the accountancy princliple terminology which is present in the accounting conceptual framework. The scene of this research will have as target the North American School of Accounting. The choice of the searched terminology is its relevance in the study of the Accounting Theory. To understand the evolution of the accountancy thought, will be boarded: the influence of the Feudal System and the Mercantilism in the European economic conception; the importance of the Industrial Revolution in the beginning of the accounting standards and the influence of England in the formation of the North American School of Accounting. With relation to U.S.A., the development of the economic-financial scene of the American society will be evaluated, focusing the contribution in the search of the construction of an applied theoretical framework to the Accounting. The economic-financial development of U.S.A. provided the sprouting of new users with specific necessities. The necessity of the user for useful information for the decision taking, unchained the process of research directed toward the establishment of an applied Accountancy terminology. In this process, the paper exerted for the responsible accountancy organisms for the accounting standards will be boarded, as well as the professionals associations which had invested in researches, aiming at to elaborate a body of accountancy principles and to adjust the accountancy procedures to the necessities of the users. To reach the research objective, a bibliographical revision in specialized literature will be effected, adopting the historical method, in the period that understands the development of the North American School of Accounting. As result of the research, it can conclude that the evolution process of the terminology which is studied presents a structural logical problem, because the impossibility of the construction of a theoretical framework, having as bases the principle terminology. The impossibility occurred in function of the reach attributed to the term, which made a difficult in its application in the elaboration of the accountancy procedures

Espiritismo e Apoio Social: o princípio da universalidade aplicado ao Departamento de Assistência e Promoção Social em dois Centros Espíritas de Natal/RN

A presente pesquisa tem como objeto de estudo o campo religioso espírita no aspecto de sócio-espiritual, junto aos trabalhadores do Departamento de Assistência Social em duas instituições: O Centro Espírita Irmãos do Caminho e Grupo Espírita Oscar Nelson, para tanto analisando comparativamente aspectos de duas instituições espíritas na cidade de Natal, respectivamente com 27 e 46 anos de funcionamento. O critério de escolha das referidas casas foi pela relevância das atividades sociais e assistenciais desenvolvidas pelas mesmas. O que se quer é verificar se existe a consciência desses trabalhadores em relação à universalidade na sua prática de acolher a todos que adentram em suas instituições, independente de religião que professem ou se expressam preconceitos ou qualquer intolerância em relação aos assistidos no Departamento de Assistência Social. Assim, compreender as casas espíritas como sistema de apoio para as pessoas em suas enfermidades quer sejam físicas, psicológicas ou espirituais, levando em conta princípios de moralidade

Imuno-histoquímica para identificação de células neoplásicas no infiltrado ativo de melanomas finos

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

Avaliação do emprego dos adsorventes: carvão ativo, chromosorb W e membrana C18 na preparação de amostras de ar para a determinação de d-aletrina em ambientes fechados

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