This thesis work deals with the volume changes during the solidification of cast irons and peritectic steels. The volume changes in casting metals are related to the expansion and/or contraction of the molten metal during solidification. Often, different types of shrinkage, namely macro- and micro-shrinkage, affect the casting quality. In addition to that, exposure of the metal casting to higher contraction or expansion during the solidification might also be related to internal strain development in samples, which eventually leads to surface crack propagation in some types of steel alloys during continuous casting. In consequence, a deep understanding of the mechanisms and control of the solidification will improve casting quality and production. All of the experiments during the entire work were carried out on laboratory scale samples. Displacement changes during solidification were measured with the help of a Linear Variable Displacement Transformer (LVDT). All of the LVDT experiments were performed on samples inside a sand mould. Simultaneously, the cooling curves of the respective samples during solidification were recorded with a thermocouple. By combining the displacement and cooling curves, the volume changes was evaluated and later used to explain the influence of inoculants, carbon and cooling rates on volume shrinkages of the casting. Hypoeutectic grey cast iron (GCI) and nodular cast iron (NCI) with hypo-, hyper- and eutectic carbon compositions were considered in the experiments from cast iron group. High nickel alloy steel (Sandvik Sanbar 64) was also used from peritectic steel type. These materials were melted inside an induction furnace and treated with different types of inoculants before and during pouring in order to modify the composition. Samples that were taken from the LVDT experiments were investigated using a number of different  methods in order to support the observations from the displacement measurements:  Differential Thermal Analysis (DTA), to evaluate the different phase present; Dilatometry, to see the effect of cooling rates on contraction for the various types of alloys; metallographic studies with optical microscopy; Backscattered electrons (BSE) analysis on SEM S-3700N, to investigate the different types of oxide and sulphide nuclei; and bulk density measurements  by applying Archimedes' principle. Furthermore, the experimental volume expansion during solidification was compared with the theoretically calculated values for GCI and NCI. It was found that the casting shows hardly any shrinkage during early solidification in GCI, but in the eutectic region the casting expands until the end of solidification. The measured and the calculated volume changes are close to one another, but the former shows more expansion. The addition of MBZCAS (Si, Ca, Zr, Ba, Mn and Al) promotes more flake graphite, and ASSC (Si, Ca, Sr and Al) does not increase the number of eutectic cells by much. In addition to that, it lowers the primary austenite fraction, promotes more eutectic growth and decreases undercooled graphite and secondary dendritic arm spacing (SDAS). As a result, the volume expansion changes in the eutectic region. The expansion during the eutectic growth increase with an increase in the inoculant weight percentage. At the same time, the eutectic cells become smaller and increase in number. The effect of the inoculant and the superheat temperature shows a variation in the degree of expansion/contraction and the cooling rates for the experiments. Effective inoculation tends to homogenize the eutectic structure, reducing the undercooled and interdendritic graphite throughout the structure. In NCI experiments, it was found that the samples showed no expansion in the transversal direction due to higher micro-shrinkages in the centre, whereas in the longitudinal direction the samples shows expansion until solidification was complete.   The theoretical and measured volume changes agreed with each other. The austenite fraction and number of micro-shrinkage pores decreased with increase in carbon content. The nodule count and distribution changes with carbon content. The thermal contraction of NCI is not influenced by the variation in carbon content at lower cooling rates. The structural analysis and solidification simulation results for NCI show that the nodule size and count distribution along the cross-sections at various locations are different due to the variation in cooling rates and carbon concentration. Finer nodule graphite appears in the thinner sections and close to the mold walls. A coarser structure is distributed mostly in the last solidified location. The simulation result indicates that finer nodules are associated with higher cooling rate and a lower degree of microsegregation, whereas the coarser nodules are related to lower cooling rate and a higher degree of microsegregation. As a result, this structural variation influences the micro-shrinkage in different parts. The displacement change measurements show that the peritectic steel expands and/or contracts during the solidification. The primary austenite precipitation during the solidification in the metastable region is accompanied by gradual expansion on the casting sides. Primary δ-ferrite precipitation under stable phase diagram is complemented by a severe contraction during solidification. The microstructural analysis reveals that the only difference between the samples is grain refinement with Ti addition. Moreover, the severe contraction in solidification region might be the source for the crack formation due to strain development, and further theoretical analysis is required in the future to verify this observation. / <p>QC 20170228</p>

As altas concentrações de aerossol fino e ultrafino observadas na atmosfera de áreas urbanas possuem um importante papel no clima local e global, devido sua interação com a radiação solar e também pela característica de formação dos núcleos de condensação de nuvens (CCN). Essas altas concentrações de partículas são responsáveis pela poluição do ar, atualmente considerada como o principal problema ambiental para a saúde pública no mundo, sendo relacionada ao câncer, doenças respiratórias, cardiovasculares e o mal de Alzheimer. Nesse contexto, o presente trabalho almejou a caracterização e discriminação de fontes poluentes para o aerossol atmosférico da cidade de São Paulo, utilizando os isótopos de Pb, Zn e Cu simultaneamente. Além disso, nesse estudo também foi realizada a avaliação do efeito das fontes locais e remotas para a ativação do CCN na atmosfera dessa região. São Paulo é a maior cidade da Região Metropolitana de São Paulo (RMSP), que por sua vez é a maior megacidade da América do Sul, e está entre as dez maiores do mundo. Amostras de aerossol urbano foram coletadas no inverno de 2013 e verão de 2014 na cidade de São Paulo. Ao mesmo tempo foram coletadas, em São Paulo e Cubatão, amostras de fontes poluentes importantes para a RMSP, como aquelas relacionadas ao tráfego veicular (combustíveis, pneu, poeira de rua e aerossol de túnel), construção civil (cimento) e à área industrial de Cubatão (aerossol). Adicionalmente, foram medidas no inverno de 2014 a concentrações de CCN, a distribuição por tamanho e a concentração em número das partículas. As determinações das composições isotópicas de Pb, Zn e Cu foram realizadas com um novo procedimento analítico, desenvolvido para a separação sequencial e purificação desses elementos, a partir de uma mesma solubilização de amostra, seguida pelas análises por espectrometria de massas empregando MC-ICP-MS e TIMS. A validação da exatidão e precisão desse procedimento foi realizada pela análise de amostras de materiais de referência, aerossol e fontes poluentes. Com base nos dados isotópicos das fontes poluentes, o tráfego veicular foi diferenciado da área industrial de Cubatão utilizando as assinaturas isotópicas de Pb dessas fontes, que demonstraram grande reprodutibilidade quando comparadas com estudos anteriores. Adicionalmente, as assinaturas isotópicas da poeira de rua e dos pneus foram discriminadas das emissões veiculares em um diagrama \'delta\'66ZnJMC vs 206Pb/207Pb. As assinaturas isotópicas de Zn e Cu da poeira de rua, emissões veiculares e cimento foram discriminadas em um diagrama \'delta\'65CuNIST vs \'delta\'66ZnJMC. As contribuições das fontes para as composições isotópicas de Pb e Zn, determinadas no aerossol da cidade de São Paulo, foram quantificadas utilizando modelos de mistura ternária. Nesses modelos o tráfego veicular (57 a 66%) foi predominante, seguido pela fonte não-caracterizada (25 a 32%), que mostrou uma assinatura isotópica de Pb e Zn específica observada nas duas campanhas. A área industrial de Cubatão apresentou contribuições de 11 a 17%, enquanto a poeira de rua contribuiu em até 18% para as assinaturas de Pb e Zn no aerossol. No inverno de 2014, o tráfego veicular local, o sal marinho e a queima de biomassa foram identificadas nas amostras de aerossol por análises de PMF, trajetórias de massas de ar e pelo sistema lidar. Também foram observados eventos de formação de aerossol secundário em 35% dos dias de medição. A ativação de CCN foi menor durante o dia em relação ao período noturno, sendo esse padrão associado principalmente as emissões do tráfego veicular local. Comparando os dias com contribuições das fontes remotas, pôde-se concluir que o material particulado proveniente do tráfego veicular durante o dia mostrou o maior efeito nos parâmetros de ativação de CCN em comparação com as fontes remotas de sal marinho e queima de biomassa. / Fine and ultrafine aerosol particles in high concentrations found in the atmosphere of urban areas, play an important role in local and global climate through interaction with solar radiation and cloud condensation nuclei (CCN) formation. These high concentrations of particles are related to the air pollution, which is the major environmental problem to the public health in the world, related with cancer, cardiovascular, respiratory and Alzheimer diseases. In this context, this study reports the simultaneous use of Pb, Zn and Cu to characterize and discriminate pollutant sources of the atmospheric aerosol from São Paulo City and evaluate the effect of local and remote sources to CCN activation in the atmosphere of this area. São Paulo is the main city of Metropolitan Area of São Paulo (MASP), which is the largest megacity in South America and rank among the ten most populous in the world. Urban aerosol samples were collected during winter of 2013 and summer of 2014 in the São Paulo city. At the same time, samples of the main pollutant sources of MASP, were sampled in São Paulo and Cubatão, such as vehicular traffic (fuels, tyres, road dust and tunnel aerosol), construction (cement) and aerosol from Cubatão industrial area. In addition, CCN concentrations, particle number concentrations and size distributions were measured during the winter of 2014 in the same sampling site. The Pb, Zn and Cu isotopic composition were determined by a new analytical procedure, developed to sequential separation of these elements, using a unique sample dissolution, followed by mass spectrometry analysis by MC-ICP-MS and TIMS. Analytical procedure validation of Accuracy and precision was carried with reference materials, aerosol and pollutant source samples. Based on isotopic data obtained on the pollutant sources, vehicular traffic was differentiated from Cubatão industrial area, using Pb isotopic fingerprints of this sources, which showed long term reproducibility when compared with previous studies. In addition, road dust and tyre isotopic signatures were discriminated from vehicular emissions in a \'delta\'66ZnJMC vs 206Pb/207Pb four isotope plot. Interestingly, Zn and Cu isotopic fingerprints of road dust, vehicular emission and cement was distinguished in a \'delta\'65CuNIST vs \'delta\'66ZnJMC four isotope plot. In order to quantify contributions of sources to Pb and Zn isotopic compositions determined in aerosol from São Paulo city, ternary mixing models were performed. In these models, vehicular traffic accounted to the main contribution (57 to 66%), followed by non-characterized source (25 to 32%), with a specific Pb and Zn isotopic signature identified in aerosol during the two campaigns. Cubatão industrial area showed contributions of 11 to 17%, whereas road dust contributed 18% to Pb and Zn isotopes in aerosol. In the winter of 2014, local vehicular traffic, sea salt and biomass burning were identified in aerosol by PMF, air masses trajectories and lidar analysis. Some new particle formation (NPF) events were identified on 35% of the sampling days. CCN activation was lower during the daytime compared to nightime periods, a pattern that was found to be associated mainly with local road-traffic emissions. Comparing the days with remote sources events, we concluded that particulate matter from local vehicular emissions during the daytime have a greater effect on CCN activation parameters than that from sea salt and biomass burning remote sources.

Este trabalho consiste no estudo de cubos de dados das regiões centrais de quatro galáxias com mesmo tipo morfológico da Via Láctea: NGC 1566, NGC 6744, NGC 613 e NGC 134. As observações foram feitas no período de 2013 a 2015 com o Integral Field Unit do Gemini Multi-Object Spectrograph do telescópio Gemini Sul. Foram utilizadas técnicas de análise de dados como Tomografia PCA, síntese espectral e Penalized Pixel Fitting. Além disso, para todos objetos, foram calculadas razões de linhas de emissão dos espectros das regiões centrais, imagens da emissão de [SII] 6716, 6731 das nuvens de alta e baixa densidades foram feitas e, em dois casos (NGC 1566 e NGC 613), analisaram-se imagens do Hubble Space Telescope para melhor entendimento do ambiente circumnuclear. Foram encontrados 6 espectros com emissão compatível com a de AGNs na amostra, sendo que, em duas galáxias, existe a possibilidade de AGNs duplos: NGC 6744 e NGC 613. No geral, todas as galáxias apresentaram populações estelares de idades variadas em suas regiões centrais, porém, predominantemente, com metalicidades altas (0.02 e 0.05). Todas as galáxias apresentaram cinemática estelar compatível com discos de rotação em torno do núcleo e, em duas galáxias (NGC 1566 e NGC 6744), foi observado um decréscimo da dispersão de velocidades estelar em direção ao núcleo, possivelmente devido à presença de estrelas jovens massivas. A emissão do featureless continuum do núcleo da galáxia de Seyfert NGC 1566 foi, pela primeira vez, isolada e estudada, sendo que foi encontrado um índice espectral igual 1.7. Uma amostra de quatro galáxias não é estatisticamente conclusiva e será necessário ampliar a amostra para um melhor entendimento global dos núcleos de galáxias de mesmo tipo morfológico da Via Láctea. / This work involved the analysis of data cubes of four nuclear regions of galaxies that have the same morphological type of the Milky Way: NGC 1566, NGC 6744, NGC 613 and NGC 134. The observations were taken in the period of 2013 to 2015 with the Integral Field Unit of Gemini Multi-object Spectrograph on the Gemini South telescope. The data were analyzed using techniques like PCA Tomography, spectral synthesis and the Penalized Pixel Fitting process. Besides that, for all the objects, emission-line ratios of the central regions were calculated, images of the emission-lines [SII]6716, 6731 of clouds of high and low densities were made and, in two cases (NGC 1566 and NGC 6744), their Hubble Space Telescope images were analyzed for better understanding of their circumnuclear regions. 6 spectra of the sample had emission compatible with that of AGNs, in two galaxies, there is a possibility of double AGN: NGC 613 and NGC 6744. In general, all the galaxies presented stellar populations with varying ages in their central regions, however mainly with high metallicities (0.02 and 0.05). All the galaxies presented stellar kinematics compatible with rotation disks around the central source and, in two galaxies (NGC 1566 and NGC 6744), there was a stellar dispersion velocity decrease toward the nuclei, possibly due to the presence of massive young stars. The featureless continuum emission of the Seyfert galaxy NGC 1566 was, for the rst time, isolated and studied. It was found that its spectral index is equal to 1.7. A sample of four galaxies is not conclusive and it is necessary to enlarge this sample to a better global understanding of the nuclei of galaxies with the same morphological type of the Milky Way.

Foram medidas as seções de choque de eletrofissão para os elementos Ta, Au e 182W de 35 MeV a 250 MeV e, através do formalismo dos fótons virtuais, as correspondentes seções de choque de fotofissão foram obtidas por desconvolução. Um método original para extração da energia média de excitação do núcleo composto é apresentado utilizando-se, como dados de entrada, apenas a seção de choque experimental de fotofissão e a probabilidade de fissão calculada. Da energia de excitação foi possível obter-se informações sobre o caminho livre médio do píon, a seção de choque píon-núcleon e o termo complexo do potencial óptico do méson no Au, Ta e 182W. / The electrofission cross sections of Au, Ta and 182W were measured in the energy range 35 - 250 MeV, and the corresponding photofission cross sections were deconvoluted by means of the virtual photon formalism. An original data analysis method was developed which allowed obtaining the excitation energy, using the experimental photofission cross sections and the calculated fission probabilities as inputs. From the excitation energy, plus an approach for the pion-nucleon interaction, the photopion mean free path in Au, Ta and 182W was deduced, along with the main characteristics of the pion-nucleon optical potential.

Made available in DSpace on 2016-04-28T20:56:43Z (GMT). No. of bitstreams: 1 Wedja Maria Oliveira Leal.pdf: 1460648 bytes, checksum: a6ed8e65009dd658c565f4ed1d19a85a (MD5) Previous issue date: 2014-04-03 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This study sought to identify the senses and the meanings of indiscipline for teachers students involved in a private university located in the East Zone of São Paulo. It was analyzed the problems of indiscipline that undergraduate teachers face and how these problems are manifested and explained by the teachers and the students. It was adopted, as the theoretical framework, the Socio-Historical Psychology. Data were collected and produced by the technique known as focus groups. The materials produced through the focus groups were transcribed and analyzed aiming to construct core meaning nuclei, as proposed by Aguiar and Ozella (2013). The results suggest that the meaning of discipline for teachers and students is very similar in appearance, although having distinct origins: both groups agreed that there is not indiscipline among undergraduate students, since the mischievous conducts are viewed by most teachers as uneducated persons typical behaviors. Students, on the other hand, saw these ills-behaviors as resulting from the ignorance about the few institutional rules. It was concluded that these notions were mainly a result of the lack of clear rules able to lay the foundation of living in the university environment. It is possible to say that this research helped to show how complex the phenomenon of indiscipline in higher education is, a phenomenon that, according to the literature, is still unexplored at this level of education / Este trabalho procurou identificar os sentidos e significados de indisciplina para docentes e discentes de uma universidade privada situada na Zona Leste da cidade de São Paulo. Para isso, foram analisados os problemas de indisciplina que os professores universitários enfrentam e como esses problemas se manifestam e são explicados tanto por eles como por seus alunos. O referencial teórico adotado foi o da Psicologia Sócio-Histórica. Os dados foram coletados e produzidos por meio da técnica conhecida como grupo focal. Os materiais colhidos por meio dos grupos focais foram transcritos e analisados mediante a proposta de Aguiar e Ozella (2013), que elucida como proceder para construir núcleos de significação. Os dados sugerem que para professores e alunos de graduação, o significado da indisciplina é bastante semelhante em sua aparência, embora uns e outros indiquem ter ele origens distintas: se para os dois grupos não há indisciplina, já que as condutas inadequadas são vistas pela maioria dos docentes como comportamentos típicos de pessoas mal-educadas, os alunos entendem que comportamentos impróprios resultam de desconhecimento das poucas regras institucionais. Conclui-se que essas opiniões decorrem, sobretudo, da falta de regras claras que alicerçassem a boa convivência no ambiente universitário. Esta pesquisa contribuiu para mostrar como é complexo o fenômeno da indisciplina na educação superior, um fenômeno que, de acordo com a revisão da literatura, ainda se encontra por desbravar nesse nível de ensino

Made available in DSpace on 2016-04-28T20:56:51Z (GMT). No. of bitstreams: 1 Elvira Maria Godinho Aranha.pdf: 2029356 bytes, checksum: cc2d3afecc02f06337b75be5de43bd0b (MD5) Previous issue date: 2015-03-04 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This research focused on three school management teams, each composed by principal, coordinator and vice-principal, from three public schools of Greater São Paulo (two state and one municipal). The general goal of the investigation was to understand the phenomenon of school management from the subjects that experience it. The specific goal of this research was to grasp the meanings the participants (principal, coordinator and vice-principal) attribute to their activity in the school. The participants (three principals, three coordinators and two vice-principals) were selected due to being part of schools that were voluntarily part of projects offered by research groups connected to Pontifícia Universidade Católica de São Paulo (Teaching Activity and Subjectivity and Language and Activities in School Contexts LACE). The information was produced with the eight participants from interviews, reflective meetings and training meetings, according to the specificities of each project and school. Anchored in the Sociohistorical Psychology, this research emphasizes the contributions from Vigotski (1925, 1926, 1927, 1930, 1934), one of its main theoretician, as well as the contributions from: Leontiev (1977; 1978a, b and c; 1983; 2004), Engeström (1987; 1999), Bakhtin (1929, 1979) and Bakhtin/Volochinov (1929-30). It also considered the works of contemporary theoreticians that discuss the subjective dimension of the human constitution process, namely: González Rey (2005a, b; 2007), Mitjáns Martinez (2005), Gonçalves and Beck (2009), Aguiar and Ozella (2006; 2013) and Aguiar, Soares and Machado (2014). It is important to highlight that, in different ways and with different emphases, all these contexts had in the Collaboration Critical Research (Pesquisa Crítica de Colaboração PCCol) (MAGALHÃES, 1998, 2009, 2011, 2012; MAGALHÃES & FIDALGO, 2007; LIBERALI, 2011, 2012) a common aspect, that proved itself relevant to both the construction of new ways of conducting the research and the results themselves. The analysis of the information, following the same conceptual alignment, is based on the theoretical methodological process named Meaning Nuclei (AGUIAR & OZELLA, 2006, 2013), which was of great contribution to the process of data abstraction in order to grasp the historical materiality and dialectics of meanings that the managers attribute to their activity. Taking into account, from the adopted perspective, that the meanings represent the synthesis of the objectivity and subjectivity, the analyses show that the managers speeches are expressions of the social reality, and more specifically in this case, of the education reality of our country, considering, however, that all meanings are dialectically constructed by historical subjects. In this sense, it became evident i) the importance of method and of a constructive interpretative analysis based on the theoretical methodological procedures called Meaning Nuclei in order to grasp the meanings the managers give their activities; ii) the importance of the role of the principal to the possibility of school improvement; iii) the relevance of the managers initial training and continuing education for the attainment of positive results in the learning of students and teachers; iv) the fundamental importance of the State in guaranteeing the human and material resources to the realization of education public policies, regarding salaries and teaching career, already determined by law; v) the contribution of research groups in promoting spaces for discussion and learning in the school; vi) the relevance of research and extension projects based on a collaborative and critical perspective in transforming the meanings the managers attribute to their activity, thus opening up the possibility for transformation in the school through new action taken by those that are responsible for it / Esta pesquisa teve como foco três equipes gestoras escolares, compostas, cada uma delas, de diretor, coordenador e vice-diretor, de três escolas públicas da Grande São Paulo (duas estaduais e uma municipal). O objetivo geral da investigação foi entender o fenômeno da gestão escolar a partir dos sujeitos que a vivenciam. O objetivo específico desta pesquisa foi apreender as significações que as participantes (diretora, coordenadora e vice-diretora) atribuem à sua atividade na escola. As participantes (três diretoras, três coordenadoras e duas vice-diretoras) foram selecionadas pelo fato de pertencerem a escolas que faziam, voluntariamente, parte de projetos oferecidos por grupos de pesquisa ligados à Pontifícia Universidade Católica de São Paulo (Atividade Docente e Subjetividade e Linguagem e Atividades em Contextos Escolares LACE). As informações foram produzidas com as oito participantes, a partir de entrevistas, reuniões reflexivas e encontros de formação, de acordo com as especificidades de cada projeto e escola. Ancorado nos pressupostos teóricos da Psicologia Sócio-Histórica, este trabalho enfatiza as contribuições de Vigotski (1925, 1926, 1927, 1930, 1934), um de seus principais teóricos, bem como as contribuições de: Leontiev (1959; 1977; 1978; 1983; 2004), Engeström (1987; 1999), Bakhtin (1929, 1979) e Bakhtin/Volochinov (1929-30). Considerou, ainda, os trabalhos dos teóricos contemporâneos que discutem a dimensão subjetiva dos processos de constituição humana, a saber: González Rey (2003, 2005a, b; 2007), Mitjáns Martinez (2005), Gonçalves e Bock (2009), Aguiar e Ozella (2006; 2013) e Aguiar, Soares e Machado (2014). É importante destacar que, de formas diferentes e ênfases diversas, todos estes contextos tiveram na Pesquisa Crítica de Colaboração PCCol (MAGALHÃES, 1998b; 2009; 2011; 2012; MAGALHÃES & FIDALGO, 2007; LIBERALI, 2011; 2012) um ponto em comum, e que tal fato se mostrou relevante tanto para construção de novas formas de condução da pesquisa como para seus resultados. Os dados foram produzidos desde 2010, foram vídeo-gravados e transcritos. A análise das informações, seguindo o mesmo alinhamento conceitual, está baseada no procedimento teórico-metodológico denominado Núcleos de Significação (AGUIAR e OZZELA, 2006; 2013), que foi de grande contribuição no processo de abstração dos dados de modo a apreender a materialidade histórica e dialética das significações que as gestoras atribuem à sua atividade. Entendendo, na perspectiva adotada, que as significações representam a síntese da objetividade e subjetividade, as análises mostram que as falas das gestoras são expressão da realidade social, mais especificamente no caso, da realidade educacional do nosso país, considerando, no entanto, que todas as significações são dialeticamente constituídas por sujeitos históricos. Nesta direção, evidenciou-se: i) a importância do método e de uma análise interpretativa construtiva baseada no procedimento teórico-metodológico nomeado Núcleos de significação para a apreensão das significações das gestoras sobre sua atividade; ii) A importância do papel do diretor para a possibilidade do avanço da escola; iii) a relevância e o peso da formação inicial e continuada das gestoras para a efetivação de resultados positivos na aprendizagem de alunos e professores; iv) A importância fundamental do Estado para garantir os recursos materiais e humanos para efetivação das políticas públicas na área educacional, em relação à salário e carreira docente já anunciadas em lei; v) A contribuição de grupos de pesquisa para promover espaços de discussão e aprendizagem na escola; vi) A relevância de projetos de pesquisa e extensão que se pautem numa perspectiva colaborativa e crítica para gerar transformações nas significações das gestoras sobre sua atividade abrindo a possibilidade de transformações na escola por meio de novas ações daqueles que se responsabilizam por ela

Made available in DSpace on 2016-04-28T20:57:08Z (GMT). No. of bitstreams: 1 PED - Julio Ribeiro Soares.pdf: 929846 bytes, checksum: fc7bcccbd8187b6f5583351fdde3ec0b (MD5) Previous issue date: 2006-11-03 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Nowadays, the topic of teacher training has played a major role in the research scenario of human sciences, namely Pedagogy and Educacional Psychology. At the same time, however, despite the fact that the understanding of some questions concerning this issue has improved significantly, there has been little research focusing more specifically on training in-service teachers. Thus, based on the issues raised above, the aim of this study is to aprehend and analyse meanings produced by teachers as regards their in-service academic training. The present analysis involves qualitative research, whose theoretical and methodological reference background was that of Sociohistorical Psychology. The study was carried out with only one subject, who teaches at the Elementary Level and was a former student of an academic in-service training course. Data were obtained from this subject by means of recurring interviews. The analysis of the data was conducted as from a proposal made by the Signification Nuclei. From the interviews, five signification nuclei were systematised as a means of approximation to the zones of meanings which shape the subject of the research in the process of her academic training. The signification nuclei are as follows: the teaching pedagogical action as a vital human activity; the pedagogical posture of the teaching trainers; the relationship between theory and pratice in the process of academic training; the affective mediation involved in being a teacher; overcoming of difficulties during the academic training period. As to the final considerations, an aspect to be highlighted is how the subject went through the process of her academic training, which not only seems to be commmitted to building up a new teacher but also a new person in her relation to the world. Hence the construction of a new individual, a new humanization / Na atualidade, o tema formação de professor tem ocupado um dos mais importantes espaços no cenário da pesquisa na área das ciências humanas, como a Pedagogia e a Psicologia da Educação. Ao mesmo tempo, porém, em que tem aumentado de forma significativa a compreensão acerca de algumas questões concernentes a esse tema, poucas são as pesquisas voltadas especificamente para a formação do professor em serviço. Dessa forma, com base nas questões acima enunciadas, nosso objetivo geral, neste trabalho, consiste em apreender e analisar os sentidos produzidos pelo professor acerca da sua formação acadêmica em serviço. Trata-se de um trabalho de pesquisa qualitativa, cujo referencial teórico-metodológico utilizado foi a Psicologia Sócio-Histórica. Trata-se, ainda, de um trabalho realizado com apenas um sujeito, que é professor do Ensino Fundamental e ex-aluno de um curso de formação acadêmica em serviço. A obtenção das informações junto ao sujeito ocorreu a partir do uso de entrevistas recorrentes. E a análise dessas informações foi realizada a partir da proposta dos Núcleos de Significação. A partir das entrevistas realizadas, inferimos e sistematizamos cinco núcleos de significação como via de aproximação às zonas de sentidos que configuram o sujeito da nossa pesquisa no processo de sua formação acadêmica. Destaquemos os núcleos de significação: a atuação pedagógica docente como uma atividade vital humana; a postura pedagógica dos professores formadores; a relação teoria e prática no processo de formação acadêmica; a mediação afetiva na constituição do ser professora; a superação das dificuldades vividas na formação acadêmica. No que se refere às considerações finais, um aspecto a ser destacado é o modo pelo qual o sujeito vivenciou o processo de sua formação acadêmica, a qual se configura como uma formação comprometida não apenas com a construção de uma nova professora, mas, de uma nova pessoa na relação com o mundo. Por isso, a construção de um novo indivíduo, de uma nova humanização

Le contrôle spatial et temporel de l'auto-assemblage de molécules fluorescentes en nano-objets organisés et en matériaux mous a été réalisé par photochimie.La photodécarbonylation quantitative du progélifiant dkDDOA sous irradiation génère le super gélifiant 2,3-didécyloxyanthracène (DDOA) à température ambiante et simultanément gélifie le DMSO. DkDDOA est réactif sous excitation avec de la lumière bleue en raison de la fonction alpha-dicétone sensible à la lumière qui est ajoutée au noyau aromatique. De plus,l’ajustement de la couleur de l'émission du gel du bleu au vert a été obtenu en ajoutant un dérivé 1,2-dicétone-5,12-diphényltétracène photo réactif qui donne un 5,12-diphényltétracène émissif vert sensibilisé par un transfert d'énergie efficace.Sous un microscope, l'irradiation laser focalisée permet la structuration de nanofibres émissives sur une surface de verre. Bien que la surface de verre soit non traitée, on peut obtenir des micropattern de nanofibres de DDOA hautement alignées. Ces surfaces émettent une lumière bleue polarisée linéairement, comme le prouve la microscopie de polarisation. L'anisotropie élevée et l'orientation des fibres ont été obtenues en contrôlant la densité de nucléation et la direction de balayage du laser focalisé. Des micropattern orientés perpendiculairement peuvent ainsi être juxtaposés sur la même surface. / The spatial and temporal control of the self-assembly of fluorescent molecules into organized nano-objects and into soft materials was achieved by photochemistry. The quantitative photodecarbonylation of the progelator dkDDOA under irradiation generates the supergelator 2,3-didecyloxyanthracene (DDOA) at room temperature and simultaneously gelates DMSO. dkDDOA is reactive under excitation withblue light due to the light sensitive alpha-diketone moiety that is added to the aromatic core.Additional colour-tuning from blue to green emission from the gel was achieved by adding a similar photoreactive 1,2-diketone-5,12-diphenyltetracene that yields a green emissive 5,12-diphenyltetracene sensitized through an efficient energy transfer. Under a microscope, focused laser irradiation enables the patterning of blue-emissive nanofibers on to a glass surface. Although the surface is non-treated, micropatterns of highly aligned DDOA nanofibers can be obtained. These surfaces emit linearly polarized blue light,as proven with polarization microscopy. The high anisotropy and the orientation of the fibers was achieved by controlling the nucleation density and the direction of scanning of the focused laser. Perpendicularly oriented micropatterns can thereby be juxtaposed on the same surface.

Dans ce travail, nous nous sommes intéressés à la brisure de la symétrie d'isospin dans les noyaux N≈Z et à son effet sur l'élément de matrice de transitions β de Fermi super-permises 0+ ➝ 0+ dans le cas de la décroissance β+ du Mn50.Dans le cadre de l'approche microscopique Highly Truncated Diagonalization Approach (HTDA), dédiée à la description des corrélations au-delà du champ moyen et conservant explicitement de nombre de particules, nous avons étudié (en particulier) le rôle joué par les corrélations d'appariement dans les mécanismes de brisure de la symétrie d'isospin dans l'état fondamental de noyaux N≈Z. Une étude de sensibilité du degré de cette brisure, en fonction de l'intensité de l'interaction résiduelle décrivant l'appariement dans HTDA, a été menée et une interprétation des mécanismes recherchés a été proposée à l'aide d'une approximation développée dans ce travail. Cette étude a mis évidence toute la complexité d'un bon traitement de la symétrie d'isospin, tant au niveau de la description de la source de brisure qu'au niveau de la limitation des biais du modèle. Nous avons également montré la nécessité d'une description très fine des fonctions d'onde corrélées dans un tel problème. Plus précisément, nous avons obtenu une valeur de la correction δc de mélange d'isospin à l'élément de matrice de transition de Fermi de (0.2±0.1)%. Cette valeur a été confrontée à celles obtenues dans d'autres approches. Compte tenu des effets négligés dans notre travail, notre valeur de δc est supposée représenter une borne minimum. / In this work, we are interested in the breaking of the isospin symmetry in the N≈Z nuclei and in its effect on the matrix element of super-allowed 0+ ➝ 0+ Fermi β transitions in the case of the β+ decay of the Mn50. Within the framework of the Highly Truncated Diagonalization microscopic Approach, dedicated to the descritption of correlations beyond the mean field and conserving explicitely the particle number, we have studied (in particular) the role played by pairing correlations in the breaking mechanisms of this symmetry in the ground state of N≈Z nuclei. A sensitivity study of the isospin mixing, as a function of the strength of the residual interaction decribing the pairing correlations in HTDA, has been carried out and an interpretation of the mechanims at work has been proposed in terms of an approximation developped in this work. This study has pointed out the complexity of a good treatment of the isospin symmetry, in the description of the breaking sources as well as in the reduction of model biases. We have also paid attention to the necessity of a very fine description of the correlated wave functions in such a problem. More precisely, we have obtained a value for the isospin mixing correction δc to the Fermi transition matrix element of (0.2±0.1)%. This value has been compared to those obtained in other approaches. Taking account of the neglected effects in our work, our value of δc is expected to be a lower bound.

Les noyaux les plus complexes sont situés entre les nombres magiques et les médianes des espaces de valence, dans des régions connues pour les changements abrupts des observables nucléaires. Dans ces régions appelées de transition de forme, le paradigme nucléaire change entre la goutte liquide vibrationnelle et le rotor statique. Sauf quelques exceptions, les noyaux de ces régions sont radioactifs, avec des demi-vies qui chutent dans les millisecondes. Complémentaires aux propriétés des états excités à basse énergie, les énergies de liaison et les rayons de charge nucléaires sont parmi les observables les plus sensibles à ces changements de structure nucléaire. Dans ce travail, une étude du phénomène de transition de forme est effectuée, par des mesures de nucléides radioactifs produits dans le laboratoire ISOLDE au CERN. Les masses des isotopes de rubidium riches en neutrons 98-100Rb et des isotopes d’or riches en protons 180,185,188,190,191Au sont mesurées avec le spectromètre de masse de type Penning ISOLTRAP. La masse de 100Rb est déterminée pour la première fois. Des déviations significatives par rapport à la littérature sont trouvées pour les isotopes 188,190Au. Une nouvelle méthode expérimentale est présentée, utilisant un spectromètre de masse à multi-réflexion comme analyseur de faisceau pour la spectroscopie laser d’ionisation résonante. La nouvelle méthode donne la possibilité d’effectuer des études de structure hyperfine atomique avec ISOLTRAP, dont on peut extraire les rayons de charge et les moments électromagnétiques nucléaires. / The most complex nuclei are situated between the magic and the mid-shell ones, in regions known for sudden changes of the trends of nuclear observables. These are the so-called shape-transition regions, where the nuclear paradigm changes from the vibrational liquid drop to the static rotor. With few exceptions, nuclei in these regions are radioactive, with half-lives dropping into the millisecond range.Complementing the information obtained from the low-lying excitation spectrum, nuclear binding energies and mean-square charge radii are among the observables most sensitive to these changes of nuclear structure. In the present work, a study of the shape-transition phenomenon is performed by measurements of radioactive nuclides produced by the ISOLDE facility at CERN. The masses of the neutron-rich rubidium isotopes 98−100Rb and of the neutron-deficient gold isotopes 180,185,188,190,191Au are determined using the Penning-trap mass spectrometer ISOLTRAP. The mass of 100Rb is determined for the first time. Significant deviations from the literature values are found for the isotopes 188,190Au. A new experimental method is presented, using a recently developed multi-reflection time-of-flight mass spectrometer as a beam-analysis tool for resonance-ionization laser spectroscopy. The new method opens the path to measurements of atomic hyperfine spectra with ISOLTRAP, from which charge radii and electromagnetic moments of radioactive nuclides can be extracted. The properties of the studied nuclides map the borders of two prominent regions of quadrupole deformation, which constrain the fine balance between pairing and quadrupole correlations in the nuclear ground states. This balance is studied by the Hartree-Fock- Bogoliubov (HFB) approach. The sensitivity of the shape-transition phenomenon to the strength of pairing correlations is demonstrated. In particular, the strong odd-even staggering of charge radii in the mercury isotopic chain is shown to result in the HFB approach from the fine interplay between pairing, quadrupole correlations and quasi-particle blocking.