Ressoador retangular defenda com quatro camadas fotônicas

Recently, planar antennas have attracted interest due to its characteristics as well as the advantages they offer compared to other types of antennas. In the area of mobile communications the need for such antennas has become increasingly intense due to development, which requires antennas that operate in multifrequency and broadband. The microstrip antennas have narrow bandwidth due to losses in the dielectric caused by irradiation. Another limitation is the radiation pattern degradation due to generation of surface waves in the substrate. Some techniques are being developed to minimize this bandwidth limitation, as is the case in the study of type materials PBG - Photonic Band Gap, to compose the dielectric material. The analysis developed in this work were performed with use of the method LTT - Transverse Transmission Line, in the field of Fourier transform that uses a component propagating in the y direction (transerve real direction of propagation z), thus treating the general equations of the fields electric and magnetic fields as a functions of y E and Hy . This work has as main objective the method LTT structures resonator line slot with four layers of material photonic PBG, for obtaining the complex resonant frequency and efficiency of this structure. PBG theory is applied to obtain the relative permittivity for the substrate biases sep compounds photonic material. Numerical-computational results in graph form in two dimensions for all the analysis are presented for the proposed structures that have photonic materials, as substrates

SAMVC sistema de autoria de museus virtuais colaborativos

The use of graphical objects three-dimensional (3D) multimedia applications is gaining more space in the media. Networks with high transmission rates, computers with large processing and graphics boost and popularize such three-dimensional applications. The areas of 3D applications ranging from military applications, entertainment applications geared up for education. Within the applications related to education, we highlight the applications that create virtual copies of cultural spaces such as museums. Through this copy, you can virtually visit a museum, see other users, communicate, exchange information on works, etc. Thereby allowing the visit museums physically distant remote users. A major problem of such virtual environments is its update. By dealing with various media (text, images, sounds, and 3D models), its subsequent handling and update on a virtual environment requires staff with specialized knowledge. Speaking of museums, they hardly have people on your team with this profile. Inside the GT-MV (Grupo de Trabalho de Museus Virtuais), funded by RNP (Rede Nacional de Ensino e Pesquisa) propose a portal for registration, amendment and seen collaborative virtual museums of Brazil. The update, be it related to work or physical space, a system with a national scale like this, would be impossible if done only by the project team. Within this scenario, we propose the modeling and implementation of a tool that allows editing of virtual spaces in an easy and intuitive as compared with available tools. Within the context of GT-MV, we apply the SAMVC (Sistema de Autoria de Museus Virtuais Colaborativos) to museums where curators build the museum from a 3D floor plan (2D). The system, from these twodimensional information, recreates the equivalent in three dimensions. With this, through little or no training, team members from each museum may be responsible for updating the system

Aplicação do método LTT às estruturas retangulares e triangulares em multicamadas e empilhadas em substratos PBG para comunicações móveis

Recently the planar antennas have been studied due to their characteristics as well as the advantages that they offers when compared with another types of antennas. In the mobile communications area, the need for this kind of antennas have became each time bigger due to the intense increase of the mobile communications that needs of antennas which operate in multifrequency and wide bandwidth. The microstrip antennas presents narrow bandwidth due the loss in the dielectric generated by radiation. Another limitation is the radiation pattern degradation due the generation of surface waves in the substrate. In this work some used techniques to minimize the disadvantages (previously mentioned) of the use of microstrip antennas are presented, those are: substrates with PBG material - Photonic Bandgap, multilayer antennas and with stacked patches. The developed analysis in this work used the TTL - Transverse Transmission Line method in the domain of Fourier transform, that uses a component of propagation in the y direction (transverse to the direction real of propagation z), treating the general equations of electric and magnetic field as functions of y and y . This work has as objective the application of the TTL method to microstrip structures with single and multilayers of rectangular and triangular patches, to obtaining the resonance frequency and radiation pattern of each structure. This method is applied for the treatment of the fields in stacked structures. The Homogenization theory will be applied to obtaining the effective permittivity for s and p polarizations of the substrate composed of PBG material. Numerical results for the triangular and rectangular antennas with single layer, multilayers resonators with triangular and rectangular patches are presented (in photonic and isotropic substrates). Conclusions and suggestions for continuity of this work are presented

Viabilidade da Utilização de Máquinas de Indução Convencionais como Motores sem Mancais Mecânicos

Electrical Motors transform electrical energy into mechanic energy in a relatively easy way. In some specific applications, there is a need for electrical motors to function with noncontaminated fluids, in high speed systems, under inhospitable conditions, or yet, in local of difficult access and considerable depth. In these cases, the motors with mechanical bearings are not adequate as their wear give rise to maintenance. A possible solution for these problems stems from two different alternatives: motors with magnetic bearings, that increase the length of the machine (not convenient), and the bearingless motors that aggregate compactness. Induction motors have been used more and more in research, as they confer more robustness to bearingless motors compared to other types of machines building with others motors. The research that has already been carried out with bearingless induction motors utilized prototypes that had their structures of stator/rotor modified, that differ most of the times from the conventional induction motors. The goal of this work is to study the viability of the use of conventional induction Motors for the beringless motors applications, pointing out the types of Motors of this category that can be more useful. The study uses the Finite Elements Method (FEM). As a means of validation, a conventional induction motor with squirrel-cage rotor was successfully used for the beringless motor application of the divided winding type, confirming the proposed thesis. The controlling system was implemented in a Digital Signal Processor (DSP)

Construções metafóricas de vida e morte: cognição, cultura e linguagem

En esta investigación, tratamos de poner de relieve los aspectos cognitivos y culturales que subyacen a las metáforas en el lenguaje. Partimos de la premisa de que nuestra comprensión a cerca del mundo se construye socio-cognitivamente, sendo la metáfora un elemento clave de esta construcción. Por lo tanto, tenemos la intención de mirar debajo de la teoría de la Teoría Cognitiva de la Metáfora, visto desde el análisis del poema Morte e Vida Severina, de João Cabral de Melo Neto, la metáfora de la vida y muerte, inferíveis en el corpus forma patrones discursivos, llamado por nosotros como el Construccionismo del Bloques. Estas metáforas se encuentran en el nivel conceptual de nuestro lenguaje, emitido por modelos cognitivos idealizados, y mostrar las relaciones entre la lengua, la cultura y la cognición. Vemos una red de integración que implica la metáfora primaria llamada, elaborado a partir de los esquemas y los dominios conceptuales y metáforas congruentes, con la participación de la noción de marco.

Processos cognitivos que operam na construção da referência: uma análise das produções textuais elaboradas na EaD - UFRN

Beneath the theoretical assumptions of Cognitive Linguistics contemporary, we analyze the cognitive processes underlying the construction of the reference in the text. To do so, we choose as corpus the written textual productions of undergraduates at the Department of Distance Education/UFRN provided in sections of responses of presential evaluation activities and activities in the Moodle virtual ambience. These activities and texts were produced in the discipline of Reading, Interpretation and Textual Production taught in the courses of Chemistry, Physics, Mathematics, Biology and Geography we monitor during the period of 2008.1 to 2010.1. Through the analysis of discursive productions, it was evident that the construction of the reference is made by means of the activation and manipulation of information acquired through our perceptual and social experiences. Thus, we confirm the cognitive assumption that the linguistic clues available in the texts of the activities serve as guides towards cognitive domains that activate the process of building reference

Letramento no trânsito: eventos e práticas na formação de condutores de veículos

In the contemporary society, the language is presented in all social spaces and assumes many different purposes in order to meet the needs that emerge from each of these sphere. In traffic, this reality is not different. To guide vehicles, it is necessary to know, by means of reading artifacts, what the legislation establishes in what concerns the way to act in this domain. Thus, this works aims at describing the practices of literacy held in events of driver trainings and know the expectations generated by drivers/learners from this training. In theoretical terms, it anchors in Literacy Studies, comprehended here as social practices (BARTON; HAMILTON, 1998; KLEIMAN, 1995, 2008; MORTATTI, 2004; STREET, 1984; OLIVEIRA, 2008, 2010; ROJO, 2009; PAZ, 2008). Genre Theory (BRONCKART, 2004, 1999; OLIVEIRA, 2010) and in your multimodal instance (KRESS; VAN LEEUWEN, 1996; DIONÍSIO, 2006). In terms of methodology, it follows the bias of qualitative research, because of its ethnographic nature (BOGDAN; BIKLEN, 1994; MINAYO, 2010; CANÇADO, 1994; CHIZZOTTI, 2005). The research corpus was generated by reading the Brazilian Traffic Code, by observing the literacy events held in Drivers Training Centers of Natal, analysis of course books used in these events, plus questionnaires with open and closed questions and semistructured interviews. The collaborators are constituted of drivers in training, and instructors who work in this field. The analyses show significant contributions regarding the placement more committed of future drivers with the welfare and safety of those who use the public roads, from the practice or reading done during the traffic training. The contribution of this work lies in the possibility to expand the discussion about the language practice uses regarding the training for the traffic, more specifically, the training of drivers of vehicles

Apreciações de alunos de inglês sobre sua produção oral: um estudo com base no sistema de avaliatividade

O vasto número de pesquisas sobre produção oral no ensino de Inglês como Língua Estrangeira (ILE) ao redor do mundo (p. ex. LITTLEWOOD, 1981; BROWN; YULE, 1983; BROWN, 1994; UR, 1996; CARTER; MCCARTHY, 1997; BROWN, 1994; 2004; ELLIS, 2008), assim como estudos sobre aspectos cognitivos e de aquisição da produção oral (SWAIN, 1985; 1995; LEVELT, 1989; SWAIN; LAPKIN, 1995; SKEHAN; FOSTER, 1997; 1999; ROBINSON, 2001; BYGATE, 2001; D‟ELY;WEISSHEIMER, 2004; GUARÁ-TAVARES, 2007; WEISSHEIMER, 2007; BERGSLEITHNER, 2009; dentre outros) têm revelado aspectos para um ensino de ILE mais eficaz e motivador. Com a proposta de contribuir para esse avanço, o presente estudo está inserido no paradigma qualiquantitativo de pesquisa no campo da Linguística Aplicada (LA), primordialmente com base nos estudos de Moita Lopes (1996; 2006), para quem a LA está centrada na resolução de problemas de uso da linguagem, cujo foco está na linguagem de natureza processual. O estudo tem como objetivo verificar as percepções de 34 alunos, de quatro turmas distintas de um curso de ILE, em uma escola privada de línguas, acerca de sua produção oral, ao participarem de atividades orais. O corpus da pesquisa foi gerado pelas respostas dos alunos a questionamentos sobre sua produção oral, em duas fases, no início e no meio do curso, além de uma entrevista semiestruturada realizada com dez dos alunos, ao final do curso, com o intuito de verificar suas percepções sobre sua produção oral. As discussões relacionadas à produção oral em sala de aula de ILE têm respaldo teórico nos trabalhos de Littlewood (1981), Brown e Yule (1983), Almeida Filho (1993), Brown (1994), Ur (1996), Carter e McCarthy (1997), Nunan (1999), Brown (2004) e Ellis (2008), que explicam fenômenos que exercem influência na produção oral, tais como afeto, interação, características de atividades orais, dentre outras variáveis em relação a aspectos cognitivos da produção oral analisadas pelos estudos de Swain (1985; 1995), Levelt (1989), Swain e Lapkin (1995), Skehan e Foster (1997; 1999), Robinson (2001) e Bygate (2001). A análise e discussão dos dados tem como base a Gramática Sistêmico-Funcional proposta por Halliday (1985; 1994) e posteriormente desenvolvida por Halliday e Hasan (1989), Halliday e Mathiessen (2004) e Eggins (2004), dentre outros. O foco desta pesquisa são os mecanismos de Apreciação, um dos domínios avaliativos do subsistema de Atitude, que por sua vez, é parte integrante do Sistema de Avaliatividade, desenvolvido por Martin (2000), Martin e Rose (2003) e Martin e White (2005). Para análise das escolhas linguísticas feitas pelos alunos, utilizamos a ferramenta computacional WordSmith Tools 6.0 (SCOTT, 2010), cuja função Wordlist (lista de palavras) foi utilizada na busca pelos tipos de processos, assim como epítetos, entre outras marcas linguísticas mais recorrentes que caracterizassem suas percepções. Os resultados revelam que nas percepções dos alunos acerca de sua produção oral, ao longo das três fases da geração dos dados para a pesquisa, eles gradativamente deixaram de mencionar aspectos afetivos quanto ao desenvolvimento de sua produção oral e passaram a perceber aspectos mais estruturais de composição da língua

Acionamento de frames e esquemas no processo de construção de sentidos no padrão discursivo charge por alunos do ensino médio

Our research has as goal to describe and analyze the main processes related to the activation of conceptual domains underlying the comprehension in the discourse pattern cartoons by the students of third grades of high school, at Professor Antonio Basílio Filho School. Theoretically, we are grounded on assumptions of Conceptual Linguistics, whose interest analyzes our cognitive apparatus in correlation with our socio-cultural and bodies experiences. We intend to check how is the process of meaning construction and integration of various cognitive domains that are activated during the reading activity. That s why, we take the concept of cognitive domains as equivalent to the structures that are stored in our memory from our sociocultural and corporeal experiences and they are stabilized, respectively, through the frames and schemas. The activation of these conceptual domains, as evidenced by our data, supports the assumption that previous knowledge from our inclusion in specific sociocultural contexts, concurrently with the functioning of our sensory-motor system are essential during the construction activity direction. With this research, we still intend to present a proposal confront the expectations of responses produced by students from the activation of frames and schemas with our predictions

Narrativas humorísticas: esquemas e frames na compreensão do risível

A Linguística Cognitiva tem como um de seus principais objetivos descrever e analisar os processos de construção de sentido. Para isso, suas pesquisas pressupõem a existência de estruturas cognitivas oriundas das experiências sensório-motoras e socioculturais dos usuários da língua, as quais são acessadas pelo sujeito durante a compreensão textual. Fundamentada teoricamente nesta abordagem cognitiva da linguagem, esta dissertação tem como objetivo nuclear descrever e analisar como os domínios cognitivos - representados pelos esquemas e frames - permitem ao leitor depreender o risível em textos humorísticos. Entende-se por esquemas os domínios das informações construídas e armazenadas na mente do sujeito, oriundas de sua experiência corporal, como ao movimentar-se ou manipular objetos. Os frames, por sua vez, são os constructos que emergem a partir da interação, estabelecida de forma dinâmica e consensual, entre os sujeitos em contextos socioculturais específicos. Percorremos este caminho não somente por acreditarmos que o efeito de humor decorrente de um texto está subordinado à ativação e ao acionamento dos esquemas e frames armazenados na mente no leitor, como ainda por crermos na existência de vários níveis de compreensão, o que explica a recuperação de trechos humorísticos em um texto. Para confirmar a nossa hipótese, utilizamo-nos da aplicação de um experimento (uma atividade, com textos humorísticos, para alunos dos ensinos Fundamental e Médio registrarem sua compreensão). Para a análise dos resultados dessa atividade, apropriamo-nos, metodologicamente, do processo da introspecção (entendida como a intuição do pesquisador e a responsável pela produção de ideias e raciocínios ao manipular os dados). Durante a observação minuciosa do nosso experimento, chegamos à conclusão de que o humor é apreendido intelectualmente quando os esquemas e frames são confrontados

A interpretação semântica dos auxiliares modais poder, precisar e dever: uma abordagem da semântica cognitiva

Apresentamos, neste trabalho, com base na semântica cognitiva, uma análise do significado, em contexto, dos auxiliares modais poder, precisar e dever. Analisamos 120 textos produzidos por candidatos ao vestibular e por alunos do ensino fundamental, como resposta da questão número três da prova discursiva de Língua Portuguesa do vestibular 2005 da UFRN, que pede aos candidatos para explicitar a diferença de sentido entre três frases, observando o uso desses três verbos. Consideramos que um item lexical não é incorporado a uma representação lingüística semântica fixa, limitada e única, mas antes, é ligado a uma representação lingüística semântica flexível e aberta que provê acesso a muitas concepções e sistemas conceituais dependente de cada contexto determinado. Com base em seu significado, um item lexical evoca um grupo de domínios cognitivos, que por sua vez, apresentam um determinado conteúdo conceitual. Isto implica em afirmar que a rede de significados lexicais vai variar conforme o conhecimento de mundo de cada um (LANGACKER, 2000). A relevância deste trabalho é proporcionar uma contribuição para a descrição semântica do português

O entardecer de uma era: técnica, poesia e pensamento em Heidegger

The thinking dialog between Heidegger s philosophy and the poetry of Hölderlin and Rilke must be dealt in language s domains. The difficulty to establish this dialog comes from the man in itself, unable to think out of the understructure of science and the modern technique. The poetic language was forgotten or ignored, turning itself obsolete in front of improvements and resources of the technique. Heidegger searches the essences to the poetry so may it be comprehended in its plenitude for the man. Technique, poetry and existence must be pronounced and investigated so the being shows itself again. To Heidegger, the man lives in a period of uncertainty due finding himself at the sunset of age. The uncertainty generates the poverty and the night of world represents the absence of god and original truth. Only with the fundamental comprehension of poetry, the man of today can project himself to the future not anymore as technique product, but with freedom to choose. The message of poetry of Hölderlin and Rilke, according to Heidegger s interpretation, transmits an alert to the contemporary man against the coming danger in his maintained relation with nature. The purpose of the following work is to build this thinking dialog, without disfigure the poetry, but taking approach over its essence, so from there to remove its true existential value.

Efeitos de interface em bicamadas magnéticas acopladas

We have developed a theoretical study of magnetic bilayers composed by a ferromagnetic film grown in direct contact on an antiferromagnetic one. We have investigated the interface effects in this systems due to the interfilms coupling. We describe the interface effects by a Heisenberg like coupling with an additional unidirectional anisotropy. In the first approach we assume that the magnetic layers are thick enough to be described by the bulk parameters and they are coupled through the interaction between the magnetic moments located at the interface. We use this approach to calculate the modified dynamical response of each material. We use the magnetic permeability of the layers (with corrections introduced by interface interactions) to obtain a correlation between the interface characteristics and the physical behavior of the magnetic excitations propagating in the system. In the second model, we calculated an effective susceptibility of the system considering a nearly microscopical approach. The dynamic response obtained by this approach was used to study the modifications in the spectrum of the polaritons and its consequences on the attenuated total reflection (ATR). In addition, we have calculated the oblique reflectivity. We compare our result with those obtained for the dispersion relation of the magnetostatic modes in these systems

Sobre a natureza dos processos físicos de aquecimento da atmosfera de estrelas do tipo solar

In the present work, we have studied the nature of the physical processes of the coronal heating, considering as basis significant samples of single and binary evolved stars, that have been achieved with the ROSAT satellite. In a total of 191 simple stars were studied, classified in the literature as giants with spectral type F, G and K. The results were compared with those obtained from 106 evolved stars of spectral type F, G and K, which belong to the spectroscopic binary systems. Accurate measurements on rotation and information about binarity were obtained from De Medeiros s catalog. We have analysed the behavior of the coronal activity in function of diverse stellar parameters. With the purpose to better clarify the profile of the stars evolution, the HR diagram was built for the two samples of stars, the single and the binary ones. The evolved traces added in the diagram were obtained from the Toulouse-Geneve code, Nascimento et al. (2000). The stars were segregated in this diagram not only in range of rotational speed but also in range of X-ray flux. Our analysis shows clearly that the single stars and the binary ones have coronal activity controlled by physical process independent on the rotation. Non magnetic processes seem to be strongly influencing the coronal heating. For the binary stars, we have also studied the behavior of the coronal emission as a function of orbital parameters, such as period and eccentricity, in which it was revealed the existence of a discontinuity in the emission of X-rays around an orbital period of 100 days. The study helped to conclude that circular orbits of the binary stars are presented as a necessary property for the existence of a higher level ofX-rays emission, suggesting that the effect of the gravitational tide has an important role in the coronal activity level. When applied the Kolmogorov-Smirnov test (KS test ) for the Vsini and FX parameters to the samples of single and binary stars, we could evidence very relevant aspects for the understanding of the mechanisms inherent to the coronal activity. For the Vsini parameter, the differences between the single stars and the binary ones for rotation over 6.3 km/s were really remarkable. We believe, therefore, that the existence of gravitational tide is, at least, one of the factors that most contribute for this behavior. About the X-rays flux, the KS test showed that the behavior of the single and the binary stars, regarding the coronal activity, comes from the same origin

Formação estelar desencadeada pela colisão entre nuvens moleculares magnetizadas

We use a finite diference eulerian numerical code, called ZEUS 3D, to do simulations involving the collision between two magnetized molecular clouds, aiming to evaluate the rate of star formation triggered by the collision and to analyse how that rate varies depending on the relative orientations between the cloud magnetic fields before the shock. The ZEUS 3D code is not an easy code to handle. We had to create two subroutines, one to study the cloud-cloud collision and the other for the data output. ZEUS is a modular code. Its hierarchical way of working is explained as well as the way our subroutines work. We adopt two sets of different initial values for density, temperature and magnetic field of the clouds and of the external medium in order to study the collision between two molecular clouds. For each set, we analyse in detail six cases with different directions and orientations of the cloud magnetic field relative to direction of motion of the clouds. The analysis of these twelve cases allowed us to conform analytical-theoretical proposals found in the literature, and to obtain several original results. Previous works indicate that, if the cloud magnetic fields before the collision are orthogonal to the direction of motion, then a strong inhibition of star formation will occur during a cloud-cloud shock, whereas if those magnetic fields are parallel to the direction of motion, star formation will be stimulated. Our treatment of the problem confirmed numerically those results, and further allowed us to quantify the relative star forming efficiencies in each case. Moreover, we propose and analyse an intermediate case where the field of one of the clouds is orthogonal to the motion and the field of the other one is parallel to the motion. We conclude that, in this case, the rate at which the star formation occurs has a value also intermediate between the two extreme cases we mentioned above. Besides that we study the case in which the fields are orthogonal to the direction of the motion but, instead of being parallel to each other, they are anti-parallel, and we obtained for this case the corresponding variation of the star formation rate due to this alteration of the field configuration. This last case has not been studied in the literature before. Our study allows us to obtain, from the simulations, the rate of star formation in each case, as well as the temporal dependence of that rate as each collision evolves, what we do in detail for one of the cases in particular. The values we obtain for the rate of star formation are in accordance with those expected from the presently existing observational data