56 resultados para Concepções alternativas
Resumo:
Le texte se rapporte à une recherche sur les conceptions d enseignants concernant l inclusion scolaire d élèves sourds , et leurs ralations avec les pratiques qu ils développent dans les classe régulières. Elle a été conduite dans une école publique régulière appartenant à la commune de Assu RN, et dont le choix méthodologique a été une approche qualitative, du genre ethnographyque. La construction des données devient d un processus d observation, de l application d entretiens demi-structurés et de l analyse de documents, ayant pour sujets quatre enseignants des années initiales de l enseignement fondamental. L apport théorique de base a été la théorie socio-culturelle proposée par Vygotsky (2003 ; 2005), censée traduire la compréhension de l homme dans sa dimension historique et culturelle, et mettre en évidence l interaction sociale en tant que condition pour le développement des individus. Les données font connaître que les enseignants sujets de la recherche sont favorables à l inclusion scolaire des élèves sourds dans les classes régulières, néanmoins soulignent le besoin d un changement à l école pour que l inclusion devienne une réalité. Les enseignants sont d avis que l apprentissage des élèves sourds se fait d une façon qui met trop de temps, moyennant l utilisation de recours spécifiques, tels que l usage du langage des signes (Libras). Ils signalent les difficultés qu ils doivent faire face quand il s agit de travailler pédagogiquement avec ces élèves dans le quotidien, telles que : manque d un travail collectif à l école ; besoin d une formation spécialisée ; démonstration de sentiments de peur, ou préjugés de la part de quelques uns du personnel de l école , tout celà interférant directement dans leurs attitudes et leurs actions faces aux élèves ; manque d appui des instances administratives de l école ; absence de politiques consistentes pour guider l éducation sous un regard inclusif. Quant aux pratiques pédagogiques développées à l école, la recherche laisse voir que, par rapport à la présence des élèves sourds, très peu d adaptations y ont été introduites, d où se dégage que la planification des actions éducatives à l école se tourne, prioritairement, vers les élèves qui écoutent, c est-à-dire, vers un groupe apparemment homogène. On a constaté, en plus, qu il n existe pas à l école aucun professionnel habilité pour l établissement d un processus de communication avec les élèves sourds. Malgré ces difficultés, les enseignants avouent, quand même, que travailler avec ces élèves rapporte toujours des bénéfices, tels que la collaboration et le respect mutuels chez les élèves, l acquisition de nouveaux savoirs et l amélioration de la pratique pédagogique des enseignants
Resumo:
The discussion we have established in this study is about how the practice is developing educational projects based on work with because the methodological choice of the teacher. The study of an ethnographic qualitative approach was conducted with a group of six teachers in two public schools in School Administrative Zone north of the city of Natal / RN. Data were constructed from semi-structured, reinforced by the direct observation of the practice of teaching of teachers. The goals outlined were to identify the reasons why the option for the project, listing the benchmarks that subsidized their construction, the observation of everyday experience in educational planning and development of projects developed. In the light of information we can notice a complex and even contradictory, which is confusing the concepts and practices are weakened. The analysis revealed inconsistencies between theory and practice in working with projects, the fruit of little theoretical development of teachers. The adoption of the project as a methodological option has meant a change in direction of the effective action didactic. Reflects on this situation, it was concluded that there is a need to broaden the understanding of the significance of this type of work, covering the different dimensions that involve the practice of research, research and training of teachers. Even preventing the intentions and initiatives of the teachers, it must be emphasized is the process of learning within an approach that focuses the process of learning in multiple dimensions, inter-relational, both the capabilities of students in the areas of knowledge.
Resumo:
This investigation proposes to analyze the teaching practice in the Child Education, considering the childhood and the Child Education conceptions declared by the teachers. It was opted as methodological approach the qualitative conception of research, marking a critical perspective of the subjects, and their relations in the educational processes. It was privileged as instruments of construction of the data, the observation of the practices of the teachers developed in the ordinary day, the semistructured interviews, and the documental analysis to complement information, through the developing report of the students, done by the teachers in the end of the teaching year. This way, from the understanding of the childhood in a social perspective, and historically constructed, considering the concrete children insertion in the social reality and the child as a whole subject and by rights, it was developed the interpretative analysis of the data. The investigated reality showed that the childhood conceptions linked to the comprehension of child and child development, declared by the teachers, subjects of the research, have been associated, in some aspects, to the present thought of thinking and acting in relation to the small child, evidencing, consequently, several limitations of pedagogical order, and the demanding evidence of a bigger development of the teachers about the question.
Resumo:
En el campo de la Educación en Ciencias, los estudios acerca de las concepciones de profesores sobre la naturaleza de la ciencia están en crecimiento en las últimas décadas en virtud de la importancia atribuida al saber sobre las ciencias. Manifestando preocupación con la temática, los trabajos de esta línea de pesquisa están investigando concepciones de profesores en formación como también los en ejercicio. Inserido en esa problemática, y preocupado con la formación inicial de profesores, este trabajo tuvo como objetivo principal investigar las concepciones de los alumnos de la Carrera de Pedagogía de UFRN (Universidad Federal de Rio Grande do Norte) acerca de la naturaleza de la ciencia, una vez que los alumnos son, o lo serán, profesores que darán clases de ciencia. El aporte teórico del estudio fue el abordaje ofrecido por la filosofía de la ciencia contemporánea, como también trabajos de literatura especializada sobre la temática NdC (Naturaleza de la Ciencia). En la parte empírica del trabajo utilizamos, como principal instrumento de colecta de datos, un cuestionario abierto, en el cual los alumnos marcaron posiciones sobre varios aspectos de la naturaleza de la ciencia. Fueron sujetos de la investigación 81 alumnos de Pedagogía, que estaban en el primer, quinto y noveno semestres (también dichos períodos ). Los resultados presentaron un acercamiento a las concepciones de los sujetos sobre la temática, indicando la presencia de una serie de concepciones poco satisfactorias de la ciencia, al lado de concepciones más consistentes con la epistemología contemporánea. En el comparativo entre los grupos, el quinto semestre presentó resultados un poco mejores que los demás, trayendo a la superficie elementos para evaluar el impacto de la formación en la construcción de las concepciones de ciencia por los alumnos
Resumo:
El presente trabajo, intitulado, Los saberes de los profesores de la Escuela Fundamental: concepciones sobre los abordajes geográficos objetiva investigar los saberes del profesor de los años iniciales de la Escuela Fundamental en relación a la naturaleza especifica de los abordajes geográficos y reflexionar como en el proceso de investigación colaborativa los profesores aprendieron los saberes específicos de los abordajes geográficos vinculando sus asimilaciones teóricas a un determinado nivel de concepción . Buscamos con base en la investigación cualitativa del tipo colaborativa y en la aplicación de diferentes procedimientos técnicos-metodológico, responder a nuestras cuestiones de estudio: ¿Cuales los saberes geográficos que los profesores construyeron en la trayectoria de sus formaciones? ¿Cómo, en el proceso de investigación colaborativa, los profesores aprendieran los saberes específicos de los abordajes geográficos? Conforme principios de la perspectiva socio-histórica. Así, utilizamos específicamente las narrativas tópicas (orales y escritas) con base en los ejes norteadores Como aprendí y lo que aprendí referentes a los saberes geográficos constituidos en la trayectoria de formación, para realizar el diagnostico de los conocimientos previos de los profesores. El proceso reflexivo y la profundización del estudio ocurrieron, respectivamente, por medio de los Seminarios de Estudios Reflexivos y de los Ciclos de Estudios Reflexivos indicando la concepción de aprehensión de los saberes propuestos en esa construcción científica. Los postulados teóricos de Ferreira (2007), Charlot (2000, 2005), Tardif (2002), Tonine (2003), Soares (2000), Moraes (2005), Pimenta (2007), entre otros, proporcionaron comprensión sobre la temática en estudio. La pesquisa ocurrió en una acción colaborativa en la escuela pública de la ciudad de Natal/RN, en el Barrio de Nova Descoberta, en el turno matutino, con tres colaboradores, que participaron voluntariamente de ese proceso: Angico, Jacarandá y Carvalho desarrollaron sus prácticas pedagógicas, en los 1ºs y 4ºs años de la Enseñaza Fundamental. Los resultados obtenidos de los análisis, apuntaron un alcance descriptivo de las concepciones de los colaboradores sobre los saberes de los abordajes geográficos, que se refieren a enumeración de los aspectos característicos del fenómeno concebido, aunque nos haya empeñado para los alcances transformadores de nuestras concepciones
Resumo:
This research focuses on inclusive in childhood education. Its purpose was to investigate and analyze the conceptions and expectations of teachers of childhood education, childhood education center form Natal/RN, on the inclusion students with disabilities, school and pedagogical practices developed and implications for students learning. Theoric base of the cultural historic perspective, the search took by qualitative analysis of numbers form the case study method. It was used methodological procedures: documentary analysis, participant observation, field journal and semi structures interview.Three teachers participated in the survey of that school had student with disabilities in their classrooms. These teachers were called: Rapunzel, Snow white e Pretty. The teacher s nouns involved the refered kind of education. The data obtained from the observation indicated the regular school of childhood education provides educational practices that promote the participation and participation and development of students with disabilities, live situation that may create barriers to learning and to the development of these children. The analysing data of interview from Bardin content analysis (1994) was based in Cunha s studies (2001) Brun (2006, 2008), Mantoam (2006, 2008), Palacios, Paniagua (2007), among others. The dada showed that correlation and divergence of perceptions and expectations about the issues surrounding inclusion in childhood education. The results shaved that teaching strategies, affective ties, sensitivity and own routine of childhood education are factors that can promote inclusive proposal, but also needs a greater fulfillment individual differences of each child in order to their potentiality. The study also shaved that the negative of pedagogic support to teacher, the ignorance of them as guidelines and strategies that include the student s diversity, the importance having positive conceptions about the learning and development of student with severe learning disabilities and the need for a pedagogic training and of a collective work at school which everybody collaborates : parents, direction, coordination getting inclusive school. Believe that this study pointed relevant issues to be focus new research, since the theme is still lacking in study, therefore emphasize, the importance of conducting research that continuous this job
Resumo:
This paper intents to investigate the repercussions of the Pró-Letramento - Alphabetization and Language Course Program in the practices and conceptions of alphabetization of learning teachers, according to their own perspectives. The program, part of the National Formation Network of the Education Ministry, in partnership with public universities since 2006, is destined to aid the formation of teachers acting in the first three years of public basic education, with the goal of qualifying them to work with alphabetization and improve quality of learning processes and results. This investigation adopted the qualitative research paradigm as well as the Case Study methodology, being our empirical field a Belém do Brejo do Cruz/PB public school. The subjects are five Program graduation female teachers, including the tutor-trainer and four graduated teachers that already teach in the first three years of basic education. The data, gathered with documental analysis, individual and collective semi-structured interview, and non-participant observation, were analyzed according with Speech Analysis principals. Based on those principals, we intersected teachers enunciations, observation sessions registries and the Program s propositions and built interpretations based on theorization taken as fundaments of the investigation, among which we highlight: studies on a criticalreflexive perspective of a teacher s formation; continued formation as a permanent development process; the principals of historical-cultural approach on alphabetization processes and development with the centrality of language; alphabetization in a interactionist approach. The analysis focused on the Program s repercussions: 1) in the teachers conceptions about: 1.1) learning; 1.2) Alphabetization and literacy; and in the practices and conceptions related to: 1.3) alphabetization in a literacy perspective and 1.4) appropriation of the writing system. The corpus analysis evidenced relations of continuity and discontinuity, approach and distancing between the teachers conceptions and the Program s propositions, as well as conceptions/significance of their speeches and related or observed practices. Observing teachers elaborations evidences the repercussion of the Program s formation, whilst also showing gaps and mismatches in their appropriation process in concepts/assumptions as well as teaching propositions. These mismatches involve interaction relationships between teachers and students, with their possibilities and limitations surrounding the Program s knowledge objects complexity, also linking to the social, economical, political, and cultural conditions that involve both the implementation of the Program in each context and the conditions in which alphabetization in public schools are developed, demanding permanent and accompanied formation processes, investments to improve work conditions and valuing teaching
Resumo:
The present investigation deals with the Curriculum and Pedagogical Practices of Young and Adults, EJA, and articulates with the conceptions and beliefs of teachers sitting. The empirical scope of this investigation consisted in the Municipal School Francisca Leonísia, located in the Agrarian Reform Settlement Serra Nova, city of Florânia/RN. Seeks to analyze the relationship between the Curriculum and Educational Practices of Young and Adult EJA - conceptions beliefs of these teachers. This work is based on qualitative research, interpretative character reflective and makes use of documentary analysis, structured interviews and reflective sessions as methodological procedures which ensure the achievement of our goals in research. These procedures allowed us to enter the practice setting and curriculum for teachers to understand how they think, prepare and practice of adult education in school curriculum research field. The documentary analysis provided the rethinking of the curriculum selected references, Political Pedagogical Project and Proposed Course of EJA, from a critical reading of concepts and conceptions given in these references, with a view to construction and reconstruction of concepts that reclaim the identity of young people and adult field, inserted in the Rural Workers Movement landless/MST. As reflective sessions were constituted in spaces of collective training and allowed the group to selfreflection e collective reflection about the ideas and beliefs that permeate the curriculum and guide their practices education in adult education. In these areas of training are also discussed current problems of adult education, the construction of an educational project of the adult education field to, warranties of learning and cultural identity of the adult education field and placed in the context of the MST. Under this view, it is concluded that the conceptions and beliefs of teachers seated directly relate to the curriculum designed, developed and practiced in adult education, as well as the educational practices that permeate the curriculum. This relation is in the midst of adversities of Rural Education, inserted in the Movement of Landless Rural Workers-MST, and requires the commitment of teachers to the necessary changes to an education are critical and emancipatory
Resumo:
On this qualitative study, it has been discussed the school inclusion paths done by a student with cerebral palsy, who we call Liz, and who was also the reference and indirect subject for this study. For the representation of landscapes found, it follows throughout historical, political and pedagogical paths, getting through the case study method references on the current Brazilian educational context, analyzing, which concepts are attributed to the inclusion and which practices are developed by educational managers and teachers in a regular school of the City of Natal/RN. The theory which based this research is supported on Vygotsky's central ideas (1991, 1997, 2004) and his followers. Furthermore, it was essential to bring to this investigative journey a literature which could dialogue with the most relevant aspects of the cultural-historical approach, emphasizing the assumptions of a progressive education tendency, which promotes the subject involvement of his/her work in the world and for the world. This way, it was necessary to seek for theoretical support on assistive technology and on alternative communication, in order to show the importance of establishing other communications, which is, to break away from the conventional pattern established by the school. On this journey it was used procedures for the data construction, such as: observation, conducting semistructured interviews and questionnaires; and document analysis that supported and legitimized the inclusion, besides the permanent field diaries record. On the access paths to this landscape it entered in the Youth and Adults Education (Educação de Jovens e Adultos - EJA), seeking to establish a dialogue among Youth and Adult Education and Special Education. It was verified that, still, there are large gaps in these policies articulation. Among the results obtained it was raised discussions on new scenery, in which Youth and Adults Education (EJA) emerges as prominent mode of the established relationships throughout the school inclusion process. There were target reflections on: the planning and evaluation systematic, the pedagogical articulation among the Youth and Adults Education (EJA) teachers and the multifunctional resource room teacher's actions and the continuous training importance of the educators involved. It was considered, therefore, that the necessary mediations for school inclusion may be sustained if the walkers are involved in a permanent contact with the nature of a proposal from the Special Education inclusive perspective
Resumo:
The present study aims to investigate the conceptions of teachers and management team of the Colégio Nossa Senhora das Neves - Natal / RN about curriculum, school architecture and possible relationships established between these components. To develop the study, we rely on the theoretical contributions of Viñao Frago (2001), Escolano (2001); Benconstta (2005), among others, about the architecture school, and with regard to curriculum, ancoramo us in theoretical reflections Silva (2000, 2006, 2008). We assume that the school place is a social construct and as such, reflects the interests of certain groups, to organize, establish ways to condition their unctions and uses. In this space, people's lives is planned, both those who work there, as those who study there. Thus, the architecture school promotes, through representations, signs, symbols and shapes, certain charges that impact the ways of being and acting subjects by establishing appropriation and expropriation of rights and legitimate forms of inclusion and exclusion. Thus, it is an expression of power. A power that is expressed in the form of lead the way people should behave in a certain space. Clarity on these aspects of the architecture school is important, since in the same way that the opinion of several experts is important to discuss the adequacy of school architecture (environmentalists, architects, engineers, planners), the / the teacher / and the / as managers / must also meet the educational nature of the architecture school, so as to present its share of contribution in order to make the post-school conducive to learning multiple. From this perspective, we analyze the concepts of four teachers and eight individuals who are part of the management team of the CNSN, whose views were seized through participant observation, semi-structured interviews and documentary analysis. The construction of the data indicated levels of conceptual curriculum varied, ranging from those rooted in traditional theories of curriculum as those regarding the curriculum tied to discursive and contextual aspects. The conceptions of architecture school, predominantly focused on the aspects of the architecture school materials and most established subject, differently, relations between curriculum and school architecture
Resumo:
This article is about a study about the training needs for teachers of elementary school in the field of Geography. It is our objective to grasp their conceptions of training needs and reflect about their formative needs to teach geography. We consider the training as reflective process that involves the movement of changes and improvement beyond of formal learning, considering its numerous dimensions. We reflected about formative needs in light of the readings of Rodrigues Esteves (1993), Silva (2000), Roberts (2006), Vieira (2010). The discussions about conceptions were based on Ferreira (2007). The empirical reference constitutes to a private school in the city of Ceará-Mirim/RN, SECAT Centro de Ensino. The social subjects of our research are five teachers who work in the initial years of elementary school. We resorted a survey (auto) biographical, based on the studies of Passeggi (2011), Delory (2008), Bertaux (2010) e Josso (2010), since it is our intention to turn to the historicity of the subject and the learning, recognizing the links between him and the world and the experiences based on for learning and adult training. As technical and methodological procedure we will use the Training Narratives, whose application allows the understanding of memories and stories of schooling teachers, since are reported events occurred during the development of the individual through seminars Biographical. We observed on the narratives constructed by the teachers the absence assignments of meanings to a reworking of the theoretical formative needs and questions of its organizing principles. However, we notice the teachers were able to develop senses and means to conceive the phenomenon in study, in a descriptive way, through articulated enunciations, including aspects and opportunities linked to their teaching practices and future formative prospects. Regarding School Geography, we based our studies in the reflections of Smith Junior (1994, 2000), Tonini (2003), Vesentini (2004) and Vlach (1991), among others. We verified that the needs evidenced by the teachers to teach geography were constructed from the contexts of their teaching practices present in their school and professional trajectories. Therefore, we noticed the need for formal pedagogical qualification so that we can conceive the phenomenon in study beyond its descriptive character, understanding that it is necessary to point out reflections and questions about the dynamics of production of global capital, which conveys its interests in the contexts that often emerge formative needs of the educational system.
Resumo:
O processo de reprodução humana é caracterizado por experiências singulares que afetam o homem e a mulher de forma diferenciada. O homem que vivencia o processo gestatório de sua companheira, mesmo não sofrendo as modificações gravídicas, enfrenta transformações relacionadas ao papel que desempenha junto à mulher gestante. Tal vivência é entremeada por significados diversos que dependem tanto da forma como ele concebe a gestação de sua companheira, como da experiência com gestações anteriores. Sendo assim, torna-se imprescindível reconhecer as concepções masculinas acerca das repercussões que uma gravidez conduz nas experiências seguintes, a fim de promover uma atenção em saúde direcionada para as necessidades apresentadas pelo homem, favorecer seu envolvimento e responsabilização no processo gestatório de sua companheira. Com base no exposto, objetivou-se compreender a concepção de homens, que vivenciam a gestação de sua companheira, acerca da influência de uma gravidez anterior sobre as demais. Para tal foi realizado uma pesquisa qualitativa por meio de entrevista semi-estruturada com homens que vivenciaram duas ou mais gestações de sua companheira com intervalo de no máximo cinco anos entre tais experiências. Cumpre ressaltar que as entrevistas ocorreram após parecer favorável de no 045/2011, emitido pelo Comitê de Ética e Pesquisa da Universidade Federal do Rio Grande do Norte. Os dados foram coletados por amostragem teórica e analisados, seguindo as etapas da Teoria Fundamentada nos Dados, sob a ótica proposta pelo Interacionismo Simbólico. Seguindo o percurso dos referenciais adotados, foram elaboradas três categorias: Sentimentos vivenciados pelo homem diante da gestação da companheira, Expectativas do homem diante da gestação da companheira e Repercussões da vivência de uma gravidez anterior sobre a seguinte. A análise das propriedades e dimensões de tais categorias suscitou à construção da teoria Influências de uma gravidez sobre a outra. Assim evidenciou-se que a gravidez anterior influencia nos sentimentos do homem diante de uma nova gestação, nas suas expectativas, principalmente quanto ao sexo do segundo filho, bem como em suas atitudes e comportamentos diante da companheira, do primogênito e do recém-nascido. Revelou-se que em todos esses aspectos ocorreram processos interativos do homem consigo mesmo, com sua companheira e com o contexto social no qual estava inserido. Assim sendo, conclui-se que a interação que o homem estabelece com a experiência anterior conduz a determinação de seus sentimentos e ações frente ao advento de uma nova gravidez. Diante disso, compreende-se que o entendimento sobre tal assunto é imprescindível para fundamentar ações do enfermeiro voltadas à inserção do homem no processo de gravidez, por meio da compreensão das repercussões de vivências anteriores na sua experiência com as demais gestações. Essa compreensão possibilitará uma dinâmica familiar favorável à adaptações requeridas em processos gestatórios seguintes, centrada na satisfação e valorização de seus membros.
Resumo:
A ausência de cuidados do homem com a saúde representa um fenômeno significativo, pois contribui para o aumento da morbidade e mortalidade masculina por causas evitáveis. Essa realidade torna-se mais relevante quando se trata do policial militar, devido às peculiaridades do seu processo de trabalho. Visto isso, considera-se que os cuidados de saúde adotados por policiais militares atrelam-se ao entendimento de que possuem sobre os agravos à saúde, o qual perpassa por concepções de gênero e da profissão. Isso levou ao seguinte questionamento: Como o policial militar concebe os cuidados com a saúde. Objetivou-se analisar concepções de policiais militares sobre cuidados com a saúde. Trata-se de um estudo exploratório e descritivo, com abordagem qualitativa, desenvolvido junto a um Batalhão Militar do Comando de Policiamento de Natal, Rio Grande do Norte, Brasil. A coleta de dados foi realizada no período de junho a julho de 2013. Essa etapa foi antecedida pela anuência do Comandante Geral da Polícia Militar do Rio Grande do Norte, sob a aprovação do Comitê de Ética em Pesquisa da Universidade Federal do Rio Grande do Norte, com o CAAE nº 15449713.7.0000.5537, e autorização formal dos entrevistados mediante a assinatura do Termo de Consentimento Livre e Esclarecido (TCLE), atendendo às exigências da Resolução 466/2012, do Conselho Nacional de Saúde, no que se refere à pesquisa com seres humanos. Participaram do estudo 21 policiais militares, do sexo masculino, que trabalhavam no policiamento ostensivo, não estavam de licença médica e apresentaram condições psicológicas e/ou físicas favoráveis para responder aos questionamentos. Os dados foram coletados por meio de entrevista semiestruturada mediante um roteiro constituído de duas partes: a primeira com questões sociodemográficas com vistas à caracterização dos participantes da pesquisa e a segunda com duas questões norteadoras relativas ao objeto de estudo. Os depoimentos foram tratados conforme o método de análise de conteúdo na modalidade de análise temática segundo Bardin. Desse processo, emergiram três categorias: hábitos de vida de policiais militares, repercussão do trabalho na saúde de policiais militares e atitudes de policiais militares em frente dos problemas de saúde. A análise dos dados foi subsidiada pelo referencial teórico do Modelo de Crenças em Saúde (Health Belief Model), de acordo com as variáveis vulnerabilidade e barreiras . Para respaldar a discussão dos resultados, buscou-se na literatura conhecimentos acerca da saúde do homem e do policial militar. Os resultados apontaram que os entrevistados procuram cuidar da saúde com práticas de exercícios físicos, alimentos saudáveis e preservação do sono. No entanto, vivenciam dores de coluna, ganho de peso, dificuldades para dormir, estresse e sofrimento psicológico. Diante disso, eles buscam apoio quando acometidos por agravos à saúde e reconhecem a necessidade de medidas de segurança durante o serviço. Portanto, notam a sua condição de vulnerabilidade em decorrência de seu ofício, porém enfrentam dificuldades na adoção de práticas preventivas de agravos a saúde. Mediante os resultados, faz-se necessário que o enfermeiro atuante junto a este público elabore, implemente e acompanhe estratégias de atenção a sua saúde
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The diesel combustion form sulfur oxides that can be discharged into the atmosphere as particulates and primary pollutants, SO2and SO3, causing great damage to the environment and to human health. These products can be transformed into acids in the combustion chamber, causing damage to the engines. The worldwide concern with a clean and healthy environment has led to more restrictive laws and regulations regulating the emission levels of pollutants in the air, establishing sulfur levels increasingly low on fuels. The conventional methods for sulfur removal from diesel are expensive and do not produce a zero-level sulfur fuel. This work aims to develop new methods of removing sulfur from commercial diesel using surfactants and microemulsion systems. Its main purpose is to create new technologies and add economic viability to the process. First, a preliminary study using as extracting agent a Winsor I microemulsion system with dodecyl ammonium chloride (DDACl) and nonyl phenol ethoxylated (RNX95) as surfactant was performed to choose the surfactant. The RNX95 was chosen to be used as surfactant in microemulsioned systems for adsorbent surface modification and as an extracting agent in liquid-liquid extraction. Vermiculite was evaluated as adsorbent. The microemulsion systems applied for vermiculite surface modification were composed by RNX95 (surfactant), n-butanol (cosurfactant), n-hexane (oil phase), and different aqueous phases, including: distilled water (aqueous phase),20ppm CaCl2solution, and 1500ppm CaCl2solution. Batch and column adsorption tests were carried out to estimate the ability of vermiculite to adsorb sulfur from diesel. It was used in the experiments a commercial diesel fuel with 1,233ppm initial sulfur concentration. The batch experiments were performed according to a factorial design (23). Two experimental sets were accomplished: the first one applying 1:2 vermiculite to diesel ratio and the second one using 1:5 vermiculite to diesel ratio. It was evaluated the effects of temperature (25°C and 60°C), concentration of CaCl2in the aqueous phase (20ppm and 1500ppm), and vermiculite granule size (65 and 100 mesh). The experimental response was the ability of vermiculite to adsorb sulfur. The best results for both 1:5 and 1:2 ratios were obtained using 60°C, 1500ppm CaCl2solution, and 65 mesh. The best adsorption capacities for 1:5 ratio and for 1:2 ratio were 4.24 mg sulfur/g adsorbent and 2.87 mg sulfur/g adsorbent, respectively. It was verified that the most significant factor was the concentration of the CaCl2 solution. Liquid-liquid extraction experiments were performed in two and six steps using the same surfactant to diesel ratio. It was obtained 46.8% sulfur removal in two-step experiment and 73.15% in six-step one. An alternative study, for comparison purposes, was made using bentonite and diatomite asadsorbents. The batch experiments were done using microemulsion systems with the same aqueous phases evaluated in vermiculite study and also 20ppm and 1500 ppm BaCl2 solutions. For bentonite, the best adsorption capacity was 7.53mg sulfur/g adsorbent with distilled water as aqueous phase of the microemulsion system and for diatomite the best result was 17.04 mg sulfur/g adsorbent using a 20ppm CaCl2solution. The accomplishment of this study allowed us to conclude that, among the alternatives tested, the adsorption process using adsorbents modified by microemulsion systems was considered the best process for sulfur removal from diesel fuel. The optimization and scale upof the process constitutes a viable alternative to achieve the needs of the market
Resumo:
The development of this work arises from the research of sociological and philosophical characters contemplating also other approaches which aims to answer the followingquestions: what is the responsibility of science teaching for the image one has about science? ; which scientific education should be designed for nowadays? . After considering the assumptions brought along by rationalism and the criticisms to the illuminist model proposed by sociology and philosophy of science, as well by the biology of the knowing process, going through discussions concerning post-modernity issues, one is given to understand that the image of science has become the central point of discussion in the last hundred years, including what concerns the area of science teaching, and that practically none of those discussions really reached natural science classes indeed. We adopt the term postontological to characterize the recent proposals on philosophy and sociology, because we evaluate that this term allows a better identification of the scientific realism crisis, which supports the existence of an ontological domain which science, and only science, is able to understand. One notices that the general public is not aware of those discussions, mainly if they are science teachers and students. So we believe that discussing the logic in which science is structured, the new understandings concerning the scientific undertaking, especially those of an externalist character, and the relationship between science and society, all of this contributes to build up a science teaching which contemplates a reflective contribution, besides allowing the inclusion of the study of other epistemologies in the educational practice. We argue that a revisionist posture seems to be the most appropriate for the contemporary scientific education, contemplating, besides the teaching of the usual science contents, discussions on the issues involving that knowledge, as well as respecting epistemologies alternative to the modern Western scientific one, in order one can work on the perception of local knowledge generated from other epistemological bases. We describe here practical activities we did involving teachers (short-term courses) and high-school students in an inland school in the Rio Grande do Norte state, in Brazil, as a way to demonstrate the possibility of interventions which can take those conceptions, discussions and changes to the classroom