Made available in DSpace on 2014-12-17T14:54:59Z (GMT). No. of bitstreams: 1 ElderECO_TESE_Capa_ate_pag86.pdf: 3877192 bytes, checksum: d9b068e5eaa76a69d5a1fa1f245dbc5d (MD5) Previous issue date: 2011-09-02 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The search for ever smaller device and without loss of performance has been increasingly investigated by researchers involving applied electromagnetics. Antennas using ceramics materials with a high dielectric constant, whether acting as a substract element of patch radiating or as the radiant element are in evidence in current research, that due to the numerous advantages offered, such as: low profile, ability to reduce the its dimensions when compared to other devices, high efficiency of ratiation, suitability the microwave range and/or millimeter wave, low temperature coefficient and low cost. The reason for this high efficiency is that the dielectric losses of ceramics are very low when compared to commercially materials sold used in printed circuit boards, such as fiberglass and phenolite. These characteristics make ceramic devices suitable for operation in the microwave band. Combining the design of patch antennas and/or dielectric resonator antenna (DRA) to certain materials and the method of synthesis of these powders in the manufacture of devices, it s possible choose a material with a dielectric constant appropriate for the design of an antenna with the desired size. The main aim of this work is the design of patch antennas and DRA antennas on synthesis of ceramic powders (synthesis by combustion and polymeric precursors - Pe- chini method) nanostructured with applications in the microwave band. The conventional method of mix oxides was also used to obtain nanometric powders for the preparation of tablets and dielectric resonators. The devices manufactured and studied on high dielectric constant materials make them good candidates to have their small size compared to other devices operating at the same frequency band. The structures analyzed are excited by three different techniques: i) microstrip line, ii) aperture coupling and iii) inductive coupling. The efficiency of these techniques have been investigated experimentally and compared with simulations by Ansoft HFSS, used in the accurate analysis of the electromagnetic behavior of antennas over the finite element method (FEM). In this thesis a literature study on the theory of microstrip antennas and DRA antenna is performed. The same study is performed about the materials and methods of synthesis of ceramic powders, which are used in the manufacture of tablets and dielectric cylinders that make up the devices investigated. The dielectric media which were used to support the analysis of the DRA and/or patch antennas are analyzed using accurate simulations using the finite difference time domain (FDTD) based on the relative electrical permittivity (er) and loss tangent of these means (tand). This work also presents a study on artificial neural networks, showing the network architecture used and their characteristics, as well as the training algorithms that were used in training and modeling some parameters associated with the devices investigated / A busca por dispositivos cada vez menores e sem perda de desempenho vem sendo cada dia mais investigada pelos pesquisadores da ?rea envolvendo eletromagnetismo apli- cado. Antenas utilizando materiais cer?micos com uma alta constante diel?trica, sejam elas atuando como substrato do elemento patch radiante ou como sendo o pr?prio ele- mento radiante est?o em evid?ncia nas pesquisas atuais, isso devido ?s in?meras vantagens que apresentam, tais como: baixo perfil, capacidade de redu??o de suas dimens?es (quando comparado a outros dispositivos), alta efici?ncia de radia??o, adequabilidade a faixa de micro-ondas e/ou ondas milim?tricas, baixo coeficiente de temperatura e baixo custo. A raz?o para essa alta efici?ncia ? que as perdas diel?tricas das cer?micas s?o muito baixas, quando comparadas ?s dos materiais comercialmente usados em placas de circuito impresso, tais como: fibra de vidro e fenolite. Essas caracter?sticas tornam os dispositivos cer?micos adequados para operar na faixa de micro-ondas. Aliando o projeto de antenas patch e/ou antenas ressoadoras diel?tricas (DRA) ao uso de certos materiais e ao m?todo de s?ntese desses p?s na fabrica??o dos dispositivos, ? poss?vel escolher um material com uma determinada constante diel?trica para o projeto de uma antena com o tamanho desejado. O objetivo principal deste trabalho consiste no projeto de antenas patches e antenas DRA sob s?ntese de p?s cer?micos (s?ntese por combust?o e por precursores polim?ricos - m?todo Pechini) nanoestruturados para aplica??es na faixa de micro-ondas. O m?todo convencional de mistura de ?xidos tamb?m foi utilizado na obten??o de p?s nanom?tricos para a confec??o das pastilhas e ressoadores diel?tricos. Os dispositivos fabricados e estudados sobre materiais de alta constante diel?trica os tornam bons candidatos ? fabrica??o de dispositivos e circuitos de dimens?es reduzidas quando comparado aos outros dispositivos tradicionais operando na mesma faixa de frequ?ncia. As estruturas analisadas s?o excitadas por tr?s diferentes t?cnicas: i) linha de microfita, ii) acoplamento por abertura e iii) acoplamento indutivo. A efici?ncia dessas t?cnicas de alimenta??o s?o investigadas experimentalmente e comparada com simula??es realizadas pelo Ansoft HFSS, utilizado na an?lise precisa do comportamento eletromagn?tico das antenas atrav?s do m?todo dos elementos finitos (FEM). Nesta tese um estudo bibliogr?fico sobre teoria de antenas de microfita e antenas DRA ? realizado. O mesmo estudo ? realizado a respeito dos materiais e dos m?todos de s?ntese dos p?s cer?micos que s?o utilizados na fabri- ca??o das pastilhas e dos cil?ndros diel?tricos que compor?o os dispositivos investigados. Os meios diel?tricos os quais serviram de suporte na an?lise das antenas patch e/ou DRA s?o analisados atrav?s de simula??es precisas utilizando o m?todo das diferen?as finitas no dom?nio do tempo (FDTD) com base na permissividade el?trica relativa (er) e tangente de perda desses meios (tand). Este trabalho ainda apresenta um estudo em redes neurais artificiais, evidenciando a arquitetura de rede utilizada e suas caracter?sticas, bem como os algoritmos de treinamento que foram usados no treinamento e na modelagem de alguns par?metros associados aos dispositivos investigados

Made available in DSpace on 2014-12-17T15:01:21Z (GMT). No. of bitstreams: 1 MariaFB_DISSERT.pdf: 1170846 bytes, checksum: 98c54baa49841a83467430bc92e8e41c (MD5) Previous issue date: 2010-02-25 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Milk from different animals can be used for dairy production. Yoghurt is a popular fermented milk product and considered to be one of the greatest importance in terms of consumer acceptance and consumption. The present research deals with the production of strawberry set-type yoghurt by mixing goat and buffalo s milk and it has the objective of taking advantage of the intrinsic characteristics of each milk to produce a final product with desirable attributes. It was conducted by analyzing five experimental groups with different proportions of goat and buffalo s milk: C 100% goat s milk; 7C3B - 70% goat s milk and 30% buffalo s milk, 5C5B - 50% goat s milk and 50% buffalo s milk, 3C7B 30% goat s milk and 70% buffalo s milk; B - 100% buffalo s milk. Each group was evaluated for total solids content and the acidification profile was monitored every 30 minutes by pH analysis. The yoghurt samples were analyzed for physical-chemical (pH, acidity, protein, fat, total and reducing sugars, ash and total solids), rheological (syneresis and viscosity) and sensory characteristics (appearance, odor, consistency and flavour). Samples with higher percentual of bubaline milk reached Vm faster, but the time necessary for pH 4.6 (Te) were similar between groups. Statistical differences (p<0.05) were observed for fat and total solids content of yoghurt, with superior values for groups higher proportions of buffalo s milk. The parameters of behavior reached by the model of Ostwald of Waale pointed yoghurt samples as non-Newtonian and pseudoplastic fluids. Yoghurt made only with goat s milk (C) had higher values (p<0.05) for syneresis, which can be explained by its fragile coagulum. Additionally, this group also had the lowest sensory scores for the attributes consistence and taste, while bubaline yoghurt (B) obtained the best acceptance indexes for all of the appraised parameters / O leite de diversos animais pode ser mat?ria-prima para produ??o de diferentes tipos de produtos l?cteos existentes no mercado. Dentre eles est? o iogurte, o qual ? considerado como um dos produtos de maior aceita??o e consumo. O presente trabalho visa estudar o processo de elabora??o de iogurte a partir de misturas de leite de cabra e de b?fala com adi??o de sabor morango. Pretende-se com isso aliar caracter?sticas intr?nsecas distintas dos dois tipos de leites de forma a obter um produto de elevada aceita??o com caracter?sticas f?sico-qu?micas e organol?pticas desej?veis. A presente pesquisa foi desenvolvida a partir de cinco grupos experimentais com diferentes propor??es de leite caprino e bubalino: C - 100% leite de cabra, 7C3B - 70% leite de cabra e 30% leite de b?fala, 5C5B - 50% leite de cabra e 50% leite de b?fala, 3C7B - 30% leite de cabra e 70% leite de b?fala, B - 100% leite de b?fala. Inicialmente cada grupo foi avaliado quanto ao teor de s?lidos totais e foi determinado o pH das amostras retiradas a cada 30 minutos para acompanhamento da acidifica??o. Os iogurtes foram caracterizados quantos aos atributos f?sico-qu?micos (pH, acidez, prote?na, gordura, AR, ART, cinzas e s?lidos totais), reol?gicos (sinerese e viscosidade) e sensoriais (apar?ncia, odor, consist?ncia e sabor). As amostras com maior percentual de leite bubalino alcan?aram a taxa m?xima de acidifica??o (Vm) mais rapidamente, mas o tempo necess?rio para alcan?ar pH 4,6 foi similar entre os grupos. Diferen?as estat?sticas entre os grupos estudados foram percebidas no percentual de gordura e s?lidos totais, os quais apresentaram valores superiores para as formula??es com maior presen?a de leite de b?fala. Os ?ndices de comportamento alcan?ados pelo modelo de Ostwald de Waale apontam que os iogurtes s?o fluidos pseudopl?sticos. Al?m disso, o comportamento das curvas de fluxo e viscosidade aparente em fun??o da taxa de cisalhamento indicam que os iogurtes se classificam como fluidos n?o Newtoniano. Os iogurtes obtidos a partir de leite de cabra (grupo C) apresentaram valores estatisticamente superiores (p< 0,05) para sinerese, o que pode ser conseq??ncia do fr?gil co?gulo formado. Adicionalmente, esse grupo, ao ser comparado com os demais, apresentou escores mais baixos para os atributos consist?ncia e sabor, enquanto o iogurte produzido apenas com leite bubalino (grupo B) obteve os melhores ?ndices de aceita??o para todos os par?metros avaliados

Made available in DSpace on 2014-12-17T15:01:25Z (GMT). No. of bitstreams: 1 PatriciaCAPC_DISSERT.pdf: 2049685 bytes, checksum: 4c9ec78c3f529e6af4cdef29256d6275 (MD5) Previous issue date: 2011-03-17 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The oil industry has several segments that can impact the environment. Among these, produced water which has been highlight in the environmental problem because of the great volume generated and its toxic composition. Those waters are the major source of waste in the oil industry. The composition of the produced water is strongly dependent on the production field. A good example is the wastewater produced on a Petrobras operating unit of Rio Grande do Norte and Cear? (UO-RNCE). A single effluent treatment station (ETS) of this unit receives effluent from 48 wells (onshore and offshore), which leads a large fluctuations in the water quality that can become a complicating factor for future treatment processes. The present work aims to realize a diagnosis of a sample of produced water from the OU - RNCE in compliance to certain physical and physico-chemical parameters (chloride concentration, conductivity, dissolved oxygen, pH, TOG (oil & grease), nitrate concentration, turbidity, salinity and temperature). The analysis of the effluent is accomplished by means of a MP TROLL 9500 Multiparameter probe, a TOG/TPH Infracal from Wilks Enterprise Corp. - Model HATR - T (TOG) and a MD-31 condutivimeter of Digimed. Results were analyzed by univariated and multivariated analysis (principal component analysis) associated statistical control charts. The multivariate analysis showed a negative correlation between dissolved oxygen and turbidity (-0.55) and positive correlations between salinity and chloride (1), conductivity, chloride and salinity (0.70). Multivariated analysis showed there are seven principal components which can explain the variability of the parameters. The variables, salinity, conductivity and chloride were the most important variables, with, higher sampling variance. Statistical control charts have helped to establish a general trend between the physical and chemical evaluated parameters / A ind?stria do petr?leo possui v?rios segmentos que podem impactar o meio ambiente. Dentre eles, a ?gua de produ??o, tem ganhado destaque na problem?tica ambiental em virtude do grande volume gerado e de sua composi??o t?xica, sendo esta uma das maiores fontes de res?duos da ind?stria do petr?leo. A composi??o da ?gua de produ??o ? fortemente dependente do campo produtor. Um bom exemplo ? a ?gua produzida na Petrobras-Unidade Operacional do Rio Grande do Norte e Cear? (UO-RNCE). Uma ?nica ETE (Esta??o de Tratamento de Efluente) desta unidade recebe efluentes de 48 po?os (onshore e offshore) o que leva a grandes varia??es na qualidade da ?gua resultando em um complicador aos futuros processos de tratamento.O presente trabalho tem como objetivo realizar um diagn?stico de uma amostra da ?gua produzida proveniente da UO RNCE em observ?ncia a determinados par?metros f?sicos e f?sico-qu?micos (concentra??o em cloreto, condutividade, oxig?nio dissolvido, pH, TOG (Teor de ?leos e graxas), concentra??o em nitrato, turbidez, salinidade e temperatura). A an?lise do efluente foi realizada por meio de uma Sonda Multiparam?trica modelo MP TROLL 9500, atrav?s do Infracal TOG/TPH da Wilks Enterprise Corp Modelo HATR T (TOG) e ainda fazendo uso do condutiv?metro da Digimed, MD 31. Os dados foram tratados atrav?s de an?lise estat?stica univariada e multivariada (an?lise de componentes principais) associada os gr?ficos de controle estat?stico. A an?lise estat?stica multivariada mostrou correla??es negativas entre oxig?nio dissolvido e turbidez (-0,55) e correla??es positivas entre salinidade e cloreto (1), condutividade, cloreto e salinidade (0,70). A an?lise multivariada indicou os sete componentes principais que podem explicar a variabilidade dos par?metros. As vari?veis, salinidade, cloreto e condutividade foram as vari?veis mais importantes, ou seja, de maior vari?ncia amostral. Com gr?ficos de controle estat?stico foi poss?vel estabelecer uma tend?ncia geral entre os par?metros f?sico-qu?micos avaliados

Made available in DSpace on 2014-12-17T15:01:56Z (GMT). No. of bitstreams: 1 LuizFSF_TESE.pdf: 2382677 bytes, checksum: 16f0fd92d4efa3b045a66f19b62ab2ea (MD5) Previous issue date: 2013-09-09 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Natural gas, although basically composed by light hydrocarbons, also presents contaminant gases in its composition, such as CO2 (carbon dioxide) and H2S (hydrogen sulfide). The H2S, which commonly occurs in oil and gas exploration and production activities, causes damages in oil and natural gas pipelines. Consequently, the removal of hydrogen sulfide gas will result in an important reduction in operating costs. Also, it is essential to consider the better quality of the oil to be processed in the refinery, thus resulting in benefits in economic, environmental and social areas. All this facts demonstrate the need for the development and improvement in hydrogen sulfide scavengers. Currently, the oil industry uses several processes for hydrogen sulfide removal from natural gas. However, these processes produce amine derivatives which can cause damage in distillation towers, can cause clogging of pipelines by formation of insoluble precipitates, and also produce residues with great environmental impact. Therefore, it is of great importance the obtaining of a stable system, in inorganic or organic reaction media, able to remove hydrogen sulfide without formation of by-products that can affect the quality and cost of natural gas processing, transport, and distribution steps. Seeking the study, evaluation and modeling of mass transfer and kinetics of hydrogen removal, in this study it was used an absorption column packed with Raschig rings, where the natural gas, with H2S as contaminant, passed through an aqueous solution of inorganic compounds as stagnant liquid, being this contaminant gas absorbed by the liquid phase. This absorption column was coupled with a H2S detection system, with interface with a computer. The data and the model equations were solved by the least squares method, modified by Levemberg-Marquardt. In this study, in addition to the water, it were used the following solutions: sodium hydroxide, potassium permanganate, ferric chloride, copper sulfate, zinc chloride, potassium chromate, and manganese sulfate, all at low concentrations (?10 ppm). These solutions were used looking for the evaluation of the interference between absorption physical and chemical parameters, or even to get a better mass transfer coefficient, as in mixing reactors and absorption columns operating in counterflow. In this context, the evaluation of H2S removal arises as a valuable procedure for the treatment of natural gas and destination of process by-products. The study of the obtained absorption curves makes possible to determine the mass transfer predominant stage in the involved processes, the mass transfer volumetric coefficients, and the equilibrium concentrations. It was also performed a kinetic study. The obtained results showed that the H2S removal kinetics is greater for NaOH. Considering that the study was performed at low concentrations of chemical reagents, it was possible to check the effect of secondary reactions in the other chemicals, especially in the case of KMnO4, which shows that your by-product, MnO2, acts in H2S absorption process. In addition, CuSO4 and FeCl3 also demonstrated to have good efficiency in H2S removal / O g?s natural, embora seja composto basicamente de hidrocarbonetos leves, apresenta tamb?m em sua composi??o gases contaminantes como o CO2 (Di?xido de carbono) e o H2S (Sulfeto de hidrog?nio). O H2S, que comumente ocorre nas atividades de explora??o e produ??o de ?leo e g?s, danifica as tubula??es de transporte do petr?leo e do pr?prio g?s natural. Por isso, a elimina??o do sulfeto de hidrog?nio levar? a significativa redu??o dos custos de opera??o e a uma melhor qualidade do ?leo destinado as refinarias, resultando assim num beneficio econ?mico, ambiental e social. Tudo isso demonstra a necessidade de desenvolvimento e aprimoramento de sequestrantes que removam o sulfeto de hidrog?nio da ind?stria de petr?leo. Atualmente existem v?rios processos para o tratamento do g?s natural, utilizados pela ind?stria petrol?fera para remo??o do H2S, no entanto, eles produzem derivados de aminas que danificam as torres de destila??o, formando precipitados insol?veis que provocam entupimento dos dutos e originam res?duos de grande impacto ambiental. Por isso, a obten??o de um sistema est?vel em meio reacional inorg?nico ou org?nico capaz de remover o sulfeto de hidrog?nio sem formar subprodutos que afetem a qualidade e o custo do processamento, transporte e distribui??o do g?s natural ? de grande import?ncia. Para estudar, avaliar e modelar a transfer?ncia de massa e a cin?tica da remo??o do sulfeto de hidrog?nio (H2S) montou-se uma coluna de absor??o contendo an?is de raschig, por onde o g?s natural contaminado com H2S atravessava uma solu??o aquosa de compostos inorg?nicos estagnada, sendo por esta absorvida. A essa coluna foi acoplado a um sistema de detec??o de H2S com interface com o computador. Os dados e Equa??es do modelo foram resolvidos pelo m?todo de m?nimos quadrados modificado de Levemberg-Marquardt. Neste estudo al?m da ?gua foram utilizadas as solu??es de hidr?xido de s?dio, permanganato de pot?ssio, sulfato de cobre, cloreto f?rrico, cloreto de zinco, cromato de pot?ssio, sulfato de mangan?s, a baixas concentra??es, na ordem de 10 ppm, com o objetivo ? avaliar a interfer?ncia entre par?metros f?sicos e qu?micos da absor??o, ou mesmo buscar um melhor coeficiente de transfer?ncia de massa como ? o caso dos reatores de mistura e colunas de absor??o operando em contra corrente. Nesse contexto a avalia??o da remo??o do H2S surge como um procedimento valioso para o tratamento do g?s natural e destino dos subprodutos do processo. Os estudos das curvas de absor??o obtidos permitiram determinar a etapa controladora da transfer?ncia de massa dos processos envolvidos, os coeficientes volum?tricos de transfer?ncia de massa e as concentra??es de equil?brio, assim como, efetuar um estudo cin?tico. Os resultados mostraram que a cin?tica de remo??o do H2S ? maior para o NaOH, mas como o estudo foi realizado em baixas concentra??es de reagente pode-se verificar o efeito das rea??es secund?rias nos outros reagentes, principalmente no caso do KMnO4, que mostra seu sub produto, MnO2, tamb?m atua na absor??o do H2S. O CuSO4 e o FeCl3 tamb?m apresentaram boa efici?ncia de remo??o

Made available in DSpace on 2014-12-17T15:04:50Z (GMT). No. of bitstreams: 1 SuelyOC.pdf: 457474 bytes, checksum: 3c2dfe00f9a22704fb474c0c1cb95e70 (MD5) Previous issue date: 2008-07-30 / The Brazilian legal documents are directing the reformulation of the courses that prepare students to be teachers. Through out the country many institutions look for to fit themselves in such documents. On the other hand, other IES (Superior Education Institutions), when they are setting up such courses they looked for to be adequate to the new public politics. Based on the National Curricular Norms to form teachers for Basic Education, in tertiary level, in 2004 it was created at the CEFET-PB,the Chemistry Course (Licenciatura) to prepare people to be teachers, whose organization. This work presents the results of a research of phenomenological nature that aimed to comprehend the teachers opinions, in the range of discussions about the current politics of formation, particularly related to the CNE/CP 1 and CNE/CP 2/2002 resolutions. This work based on the curricular proposal for the Chemistry Course (Licenciatura), presents the relationship between the probationary period and the teaching practice at the CEFET-PB, in order to contribute for a reflection about these categories to clarify the teachers of the course. It started from the consideration of all changes operated in contemporary society implies changes on teacher's pedagogical practices. It was used tow instruments for the data collection: a questionnaire with open and closed questions and recordable interviews. Nine teachers form the CEFET-PB took apart and four licensed teachers. It was based in a theoretic frame as a support for discussions about the different models of teachers formation. We concluded that the representations of teachers about probationary period the practice on the activity for the teachers formation was strongly anchored in characteristic elements of the formative tendency of a institution that historically acted on a technician formation, and the results pointed to strong signs of attitudes based on a model of the technical rationality / Os documentos legais brasileiros est?o orientando a reformula??o dos cursos de forma??o de professores. Em todo o pa?s muitas institui??es procuram se adequar a tais documentos. Outras Institui??es de Ensino Superior IES j? na implanta??o dos cursos procuravam se adequar ?s novas pol?ticas p?blicas. Com base nas Diretrizes Curriculares Nacionais, para a forma??o de professores da Educa??o B?sica, em n?vel superior, cria-se em 2004 o Curso de Licenciatura em Qu?mica no CEFET-PB, cuja organiza??o curricular atende as solicita??es dos documentos legais. Este trabalho apresenta os resultados de uma pesquisa de natureza fenomenol?gica que visou compreender as opini?es de professores, no ?mbito das discuss?es sobre as atuais pol?ticas de forma??o, particularmente as relativas ?s resolu??es CNE/CP 1 e CNE/CP 2/2002. Ap?ia-se na proposta curricular para o curso de Licenciatura em Qu?mica, apresenta a quest?o da rela??o entre o est?gio e a pr?tica de ensino no CEFET-PB, a fim de contribuir acerca de uma reflex?o sobre estas categorias para esclarecer os professores formadores. Partiu da considera??o de que as mudan?as operadas na sociedade contempor?nea implicam mudan?as nas pr?ticas dos professores. A coleta de dados contou com dois instrumentos: um question?rio com quest?es fechadas e abertas e entrevistas gravadas. Participaram 9 professores do CEFET-PB e 4 licenciandos. Fundamentou-se em um quadro te?rico como suporte para as discuss?es sobre os diferentes modelos de forma??o docente. Conclu?mos que as representa??es de professores sobre est?gio e pr?tica de ensino como eixo articulador entre teoria e pr?tica na atividade de forma??o docente est? fortemente ancorada em elementos caracter?sticos da tend?ncia formativa de uma institui??o que historicamente atuava na forma??o de t?cnicos, e os resultados apontam para fortes ind?cios de atitudes baseadas no modelo da racionalidade t?cnica

Made available in DSpace on 2014-12-17T15:04:53Z (GMT). No. of bitstreams: 1 MelquesedequeSF_DISSERT.pdf: 1824466 bytes, checksum: 929840cabf2a0689d83ec85f1db69d89 (MD5) Previous issue date: 2010-07-05 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / In this work it is presented a research developed in the initial training of teachers of the chemistry graduation course at the Universidade Federal do Rio Grande do Norte (UFRN). The intervention was realized in two classes in the context of a discipline in the curricular structure with nineteen undergraduate students of chemistry. The study utilizes characteristics of the qualitative approach and uses observation, questionnaires, interviews and examination papers. The experiment involved a sequence of activities fundamented on the Problem Solving (PS) teaching strategy to approach chemical concepts. The proposal was planned and organized according to the theoretical presupposition of the work developed by the authors of the Science Education in PS, of teaching experience and from the initial hypotheses of the research. The goal was that the future teachers could experience the strategy and advance to the new meanings. The themes addressed in the activities were the difference between exercises and problems, exercises turning into problems, the steps of problem solving and some implications of the teaching strategy for the work of the teacher. The results showed evidence that through a process of collective reflection, and from the difficulties experienced in the strategy practice, the undergraduates are introduced to new perspectives of reflection and action of teaching practice, and understanding some benefits of innovative proposals for the teaching of chemistry. It also showed that, although this theme is approached, in some moments of the graduation, the future teachers don&#8223;t know when or how to realize activities in this perspective. From the aspects that rose in research we highlighted the difficulties in the problem solving steps, the use of the strategy in school and the knowledge and skills of the teacher for planning activities in Problem Solving / Neste trabalho ? apresentada uma experi?ncia desenvolvida durante a forma??o inicial de professores no curso de Licenciatura em Qu?mica da Universidade Federal do Rio Grande do Norte (UFRN). A interven??o se deu em duas turmas no contexto de uma disciplina da estrutura curricular com dezenove licenciandos de qu?mica. A pesquisa traz elementos da abordagem qualitativa e fez uso da observa??o, de question?rios, entrevistas e prova pedag?gica. A experi?ncia envolveu uma sequ?ncia de atividades fundamentadas na estrat?gia de ensino por Resolu??o de Problemas (RP) para abordar conceitos qu?micos. A proposta foi planejada e organizada de acordo com os pressupostos te?ricos dos trabalhos desenvolvidos por autores da Did?tica das Ci?ncias em RP, da experi?ncia docente e de hip?teses iniciais da investiga??o. O objetivo era que os futuros professores pudessem vivenciar a estrat?gia e avan?ar para os novos significados. Os temas abordados nas atividades foram as diferen?as entre os exerc?cios e problemas, a transforma??o de exerc?cios em problemas, as etapas de resolu??o de problemas e algumas implica??es da estrat?gia de ensino para o trabalho docente. Os resultados evidenciaram que, atrav?s de um processo de reflex?o coletiva, e a partir das dificuldades encontradas na pr?tica da estrat?gia, os licenciandos s?o introduzidos em novas perspectivas de reflex?o e a??o da pr?tica de ensino e de compreens?o de alguns benef?cios de propostas inovadoras para o ensino de qu?mica. Revela tamb?m que apesar do tema RP ser abordado, em alguns momentos durante o curso de gradua??o, os futuros professores sinalizaram que n?o sabem como e quando realizar atividades nessa perspectiva. Dos aspectos que emergiram na investiga??o destacamos as dificuldades nas etapas de resolu??o de problemas, a utiliza??o da estrat?gia no contexto escolar e os conhecimentos e habilidades do professor para planejar atividades em RP

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-01-12T14:45:07Z No. of bitstreams: 1 JeffersonAndreyLopesMatias_DISSERT.pdf: 3431273 bytes, checksum: 4b617573df442222cd8c54fadc83dbec (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-01-18T15:13:51Z (GMT) No. of bitstreams: 1 JeffersonAndreyLopesMatias_DISSERT.pdf: 3431273 bytes, checksum: 4b617573df442222cd8c54fadc83dbec (MD5) / Made available in DSpace on 2017-01-18T15:13:51Z (GMT). No. of bitstreams: 1 JeffersonAndreyLopesMatias_DISSERT.pdf: 3431273 bytes, checksum: 4b617573df442222cd8c54fadc83dbec (MD5) Previous issue date: 2016-06-23 / O estudo sobre a habilidade de explicar as Rea??es Qu?micas como um sistema complexo apresenta um importante significado para o desenvolvimento cient?fico cr?tico do estudante no s?culo XXI e compreens?o do ensino de Qu?mica. No entanto a forma como esse conte?do ? trabalhado em sala de aula, principalmente no ensino tradicional, n?o valoriza sua abordagem na forma de um sistema complexo, ou seja, de uma forma n?o fragmentada e global em sua ess?ncia. A disserta??o aqui apresentada tem como objetivo identificar e caracterizar os erros dos estudantes nas quest?es objetivas dos vestibulares da UFRN no per?odo de 2009 a 2013 sobre Rea??es Qu?micas, utilizando os dados dispon?veis pelo Observat?rio da Vida do Estudante Universit?rio (OVEU). A matriz te?rica do estudo se estruturou tendo como base as categorias e os erros de aprendizagem dos estudantes sobre Rea??es Qu?micas (N??EZ, RAMALHO, 2012), as Rea??es Qu?micas como um sistema complexo (N??EZ, 1992; RESHETOVA, 1988; SANDERSON, 1968), sendo o fundamento te?rico do produto a teoria de Galperin (N??EZ, 2009). O percurso metodol?gico envolveu uma abordagem qualitativa e quantitativa de cada quest?o objetiva das provas de vestibulares, assim como dos relat?rios da Comperve. Os resultados apresentaram os erros de aprendizagem a partir da analise das categorias das quest?es objetivas. Identificou que o tema aspectos qualitativos das Rea??es Qu?micas estiveram presentes na maioria dos erros cometidos pelos estudantes. Este conte?do conceitual tamb?m foi observado na quest?o com menor desempenho por parte dos estudantes (25,1% de ?ndice de acerto). A an?lise tamb?m trouxe contribui??es inovadoras como a an?lise da natureza de cada quest?o, relacionada ? sua resolu??o integral ou parcial de acordo com a Base Orientadora da A??o de N??ez (1992). A partir dos resultados obtidos e analisados, estabeleceu a proposta de um produto, que corresponde a uma Unidade Did?tica, que possibilite auxiliar o professor de Qu?mica na forma??o da habilidade de explicar uma Rea??o Qu?mica como um sistema complexo. / The study on the ability to explain the chemical reactions as a complex system has an important meaning for the student's critical scientific development of the twenty-first century and for the understanding of chemistry's teaching. However the way this content is working in the classroom, especially in the traditional teaching, not value your approach in the form of a complex system, that is, a form non-fragmented and global in its essence. The dissertation presented here aims to identify and characterize the errors of students in objective questions of vestibular UFRN from 2009 to 2013 Chemical Reactions, using the data available by the ?Observat?rio da Vida do Estudante Universit?rio (OVEU)?. The theoretical framework of the study was structured based on categories and student?s learning errors about chemical reactions (N??EZ, RAMALHO, 2012), chemical reactions as a complex system (N??EZ, 1992; RESHETOVA, 1988; SANDERSON, 1968), and the theoretical foundation of the product, the Galperin's theory (N??EZ, 2009). The methodological course involved a qualitative and quantitative approach to each question of college entrance tests, in the same way as of the Comperve reports. The results showed the learning errors based on the analysis of the issues categories. It identified the theme qualitative aspects of Chemical Reactions were present in most of the mistakes made by the students. This conceptual content was also observed on the issue with lower performance by the students (25.1% success rate). The analysis also brought innovative contributions like the analysis of the nature of each issue, related to their full or partial resolution in accordance with the 'Guiding Basis for Action' by N??ez (1992). Based on the obtained and analyzed results, it was established the proposal of a product that corresponds to a 'Didactic Unit' which allows help the teacher of Chemistry in the formation of the ability to explain a chemical reaction as a complex system.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-04-03T19:41:30Z No. of bitstreams: 1 SarahPollyanaDiasDosSantos_DISSERT.pdf: 10111393 bytes, checksum: 44cc6b08e8b21238733661e330e1b811 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-04-05T19:31:53Z (GMT) No. of bitstreams: 1 SarahPollyanaDiasDosSantos_DISSERT.pdf: 10111393 bytes, checksum: 44cc6b08e8b21238733661e330e1b811 (MD5) / Made available in DSpace on 2017-04-05T19:31:53Z (GMT). No. of bitstreams: 1 SarahPollyanaDiasDosSantos_DISSERT.pdf: 10111393 bytes, checksum: 44cc6b08e8b21238733661e330e1b811 (MD5) Previous issue date: 2016-07-14 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Aspidosperma pyrifolium Mart., esp?cie nativa da caatinga com grande ocorr?ncia no nordeste, conhecida popularmente como pereiro, utilizada na medicina popular no tratamento de doen?as e enfermidades. Consta na literatura diversos trabalhos realizados, relatando a presen?a de classes de compostos org?nicos como alcaloides, entre outras, que seriam respons?veis por propriedades terap?uticas existentes nessa esp?cie. O estudo fitoqu?mico de A. pyrifolium, das fra??es da semente e cascas do fruto, utilizando m?todos cromatogr?ficos cl?ssicos e purifica??o por CLAE, nos permitiu o isolamento de tr?s compostos. A partir da fra??o hex?nica das cascas do fruto (APCF-H) foi isolado o triterpeno ?cido betul?nico, n?o relatado anteriormente na esp?cie A. pyrifolium. Das fra??es diclorometano (APSE/DCM) e acetato de etila 50% dicloromentano (APSEA/50% DCM) das sementes foi poss?vel o isolamento do alcaloide plumerano pentac?clico aspidospermina, do alcaloide ?-carbolina glicosilado Cordifolina, n?o descrito anteriormente na esp?cie e outro composto do tipo ?-carbolina que n?o possui uma estrutura elucidada at? o momento. O extrato das sementes fra??o diclorometano (APSE/DCM) foi analisado por CG/EM (cromatografia gasosa acoplada a espectrometria de massa) e seus dados foram comparados com dados na literatura em banco de dados (NIST08.LIB), foi identificada a presen?a dos alcaloides 1-acetil-aspidospermidina, aspidospermina e pirifolina, dentre outros compostos minorit?rios. A avalia??o da atividade antioxidante, pelo m?todo sequestrador de radical livre de DPPH (2,2-difenil-1picril-hidrazila), da fra??o APSE/DCM apresentou um percentual de atividade antioxidande m?ximo (AA% m?ximo) de 83,68%, com concentra??o inibit?ria 50% (IC50) 133,4867 ? 2,22. A fra??o das sementes fra??o diclorometano (APSE/DCM) foi avaliada em rela??o ? toxicidade contra Artemia salina, tendo em vista que j? existiam relatos da toxicidade nas folhas de A. pyrifolium, comprovamos a toxicidade aguda nas fra??o das sementes diclorometano com concentra??o letal m?dia (CL50) em 24 horas de 1,1524 ?g.ml-1, sendo consideradas t?xicas as esp?cies que apresentam CL50 inferior a 1000 ?g.ml-1. Na segunda parte do trabalho foi realizado um levantamento bibliogr?fico de alcaloides do tipo ?-carbolina de ocorr?ncia natural, com suas estruturas, atividades relatadas e um banco de dados com seus deslocamentos qu?micos em RMN 1H e 13C, totalizando 169 alcaloides descritos na literatura, do per?odo de 1992 a 2016, agrupados em quatro principais grupos, denominados ?-carbolina, dihidro-?-carbolina, tetrahidro-?-carbolina e os ?-carbolinas divergentes, este levantamento auxiliar? na elucida??o estrutural de novas mol?culas. / Aspidosperma pyrifolium Mart., a native species of the caatinga with great occurrence in the northeast, known perpularmente as pereiro, used in popular medicine in the treatment of diseases and diseases. There are several studies carried out in the literature, reporting the presence of classes of organic compounds such as alkaloids, among others, that would be responsible for the therapeutic properties of this species. The phytochemical study of A. pyrifolium, seed fractions and fruit peels using classical chromatographic methods and purification by HPLC allowed us to isolate three compounds. From the hexanic fraction of fruit peels (APCF-H) was isolated the betulinic acid triterpene, not previously reported in the A. pyrifolium species. From the dichloromethane (APSE/DCM) and ethyl acetate 50% dichloromethane (APSEA / 50% DCM) fractions of the seeds, it was possible to isolate the pentacyclic pentameric aspidospermine alkaloid from the glycosylated ?-carboline alkaloid Cordifolina, not previously described in the species and another compound of the ?-carboline type that does not have a structure elucidated until the moment. The extract of the seeds dichloromethane fraction (APSE/DCM) was analyzed by GC/MS (gas chromatography coupled to mass spectrometry) and its data were compared with data in the literature in database (NIST08.LIB), the presence of the alkaloids 1-acetyl-aspidospermidine, aspidospermine and pyrifoline, among other minor compounds. The antioxidant activity evaluation of the APSE/DCM fraction showed a percentage of maximum antioxidant activity (AA% maximum) of 83.68%, with the free radical sequestration method of DPPH (2,2-diphenyl-1-picryl-hydrazila). Inhibitory concentration 50% (IC50) 133.4867 ? 2.22. The fraction of the seeds dichloromethane fraction (APSE/DCM) was evaluated in relation to the toxicity against Artemia salina, considering that there were already reports of the toxicity in the leaves of A. pyrifolium, we verified the acute toxicity in the seed dichloromethane fraction with average lethal concentration (CL50) in 24 hours of 1.1524 ?g.ml-1, species with CL50 less than 1000 ?g.ml-1 being considered toxic. In the second part of the work a bibliographic survey of naturally occurring ?-carboline alkaloids with their structures, reported activities and a database with their chemical displacements in 1H and 13C NMR were carried out, totaling 169 alkaloids described in the literature. From 1992 to 2016, grouped into four main groups, named ?-carboline, dihydro-?-carboline, tetrahydro-?-carboline and the divergent ?-carbolines, this survey will aid in the structural elucidation of new molecules.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-06-02T19:23:34Z No. of bitstreams: 1 AdrianoMartinezBasso_DISSERT.pdf: 3012448 bytes, checksum: 3c69a91b0526381ccdc056272f1dba47 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-06-05T22:54:43Z (GMT) No. of bitstreams: 1 AdrianoMartinezBasso_DISSERT.pdf: 3012448 bytes, checksum: 3c69a91b0526381ccdc056272f1dba47 (MD5) / Made available in DSpace on 2017-06-05T22:54:44Z (GMT). No. of bitstreams: 1 AdrianoMartinezBasso_DISSERT.pdf: 3012448 bytes, checksum: 3c69a91b0526381ccdc056272f1dba47 (MD5) Previous issue date: 2017-03-28 / Este trabalho teve como objetivos determinar as composi??es fisicoqu?mica e mineral das sementes da jaca mole (JM) e da jaca dura (JD) desidratada, das polpas da JM e da JD desidratada, liofilizada e in natura. Para isto, foram determinados os percentuais de: umidade, cinza, lip?deos, prote?na e carboidrato. Foram analisadas por ICP-OES as concentra??es dos elementos: c?lcio, cobre, ferro, magn?sio, cromo, mangan?s, pot?ssio, s?dio, zinco, n?quel e cobalto. Os resultados mostraram que as sementes da JM e da JD t?m composi??es bromatol?gicas muito pr?ximas: 63% de umidade, 18% de carboidrato, 15% de prote?na e 3% de cinzas. A maior diferen?a foi no teor de lip?deos (0,4% - JM e 0,9% - JD). As composi??es minerais s?o bem distintas. O pot?ssio e o magn?sio s?o os mais abundantes em ambas as variedades (95,8% - JM e 93,2% - JD). As sementes de JD t?m 5,5 vezes mais Na, 24% mais Ca, 3 vezes mais Zn e 2% mais K. As sementes de JM t?m 32% mais Fe, 37% mais Mn e 16% mais Mg. Do ponto de vista fisicoqu?mico, as polpas t?m uma grande distin??o. A polpa da JD tem 9,5 vezes mais lip?deos e o dobro de carboidrato. A polpa da JM tem 10% mais umidade e 14% mais cinza. O teor de prote?na ? muito semelhante. Nas polpas, a composi??o de minerais ? bem diferente, embora o pot?ssio e o magn?sio sejam os elementos majorit?rios nas duas variedades. (96,1% - JM e 92,4% - JD). A polpa de JM tem 33% mais K, 29% mais Mg, 26% mais Mn, 48% mais Na, 16% mais Cu, 24% mais Fe e 5% mais Zn. A polpa da JD tem 45% mais Ca, o que pode explicar sua maior firmeza. A composi??o qu?mica das polpas da JM e da JD in natura s?o muito parecidas em rela??o ?s concentra??es de Fe, Cu, Mn e Mg. A polpa da JD in natura tem 2,6 vezes mais Ca e 27% mais Zn. A variedade mole in natura tem 5% mais K e 25% mais Na. A liofiliza??o preservou mais o teor de carboidratos nas polpas das duas variedades de jaca. Os resultados foram submetidos ao teste t pareado, com 95% de signific?ncia, para inferir sobre a signific?ncia da igualdade ou desigualdade dos par?metros comparados. / This work had as objectives to determine the physicochemical and mineral compositions of the dehydrated seeds of the soft jackfruit (SJ) and of the hard jackfruit (HJ), of the dehydrated, in nature and lyophilized pulps of the SJ and HJ. For this, were determined the percentages of: moisture, ash, lipids, protein and carbohydrate. The concentrations of the elements calcium, copper, iron, magnesium, chromium, manganese, potassium, sodium, zinc, nickel and cobalt were analyzed by ICP-OES. The results showed that the seeds of SJ and of HJ have very close bromatological compositions: 63% moisture, 18% carbohydrate, 15% protein and 3% ash. The major difference was in the lipids contente (0,4% - SJ and 0,9% - HJ). The mineral compositions are quite distinct. Potassium and magnesium are the most abundant in both varieties (96% - SJ and 93% - HJ). The seeds of HJ have 5,5 times more Na, 24% more Ca, 3 times more Zn and 2% more K. The seeds of SJ have 32% more Fe, 37% more Mn and 16% more Mg. From a physicochemical point of view, the pulps have a great distinction. The pulp of HJ has 9,5 times more lipids and twice the carbohydrate. The pulp of SJ has 10% more moisture and 14% more ash. The protein content is very similar. In pulps, the composition of minerals is quite different, although potassium and magnesium are the major elements in the two varieties (96% - SJ and 93% - HJ). The pulp of SJ has 33% more K, 29% more Mg, 26% more Mn, 48% more Na, 16% more Cu, 24% more Fe and 5% more Zn. The pulp of HJ has 45% more Ca, which may explain its greater firmness. The chemical composition of the pulps in nature of SJ and HJ are very similar in relation to the concentrations of Fe, Cu, Mn and Mg. The HJ in nature pulp has 2,6 times more Ca and 27% more Zn. The in nature soft variety has 5% more K and 25% more Na. The freeze-drying preserved the carbohydrate content in the pulps of the two varieties of jackfruit. The SJ lyophilized pulp had the lower metal content than the pulp dehydrated in the oven. The results were submitted to the paired t test, with 95% significance, to infer the significance of the equality or inequality of the parameters compared.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-08-01T13:17:38Z No. of bitstreams: 1 BraulioAlvesDeAlbuquerque_DISSERT.pdf: 2952166 bytes, checksum: cb58a9a3371e301e81b555ba4a258920 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-08-04T19:25:30Z (GMT) No. of bitstreams: 1 BraulioAlvesDeAlbuquerque_DISSERT.pdf: 2952166 bytes, checksum: cb58a9a3371e301e81b555ba4a258920 (MD5) / Made available in DSpace on 2017-08-04T19:25:31Z (GMT). No. of bitstreams: 1 BraulioAlvesDeAlbuquerque_DISSERT.pdf: 2952166 bytes, checksum: cb58a9a3371e301e81b555ba4a258920 (MD5) Previous issue date: 2017-06-09 / Os conhecimentos sistematizados que s?o ministrados aos estudantes na escola, geralmente n?o ultrapassam esse espa?o. S?o consequ?ncias de uma abordagem educativa de transmiss?o/recep??o, que frequentemente se demonstram insuficientes na realiza??o de uma contextualiza??o. Logo, a utilidade destes saberes se restringe a reprodu??o do que foi dito pelo professor. Isto acaba colocando os educandos como meros espectadores na produ??o do conhecimento. Repensar e propor interven??es no papel que cada indiv?duo envolvido no processo de ensino e aprendizagem apresenta, ? uma constante necessidade, visto as mudan?as recorrentes nos objetivos educacionais. Esse estudo procurou implementar uma proposta de ensino de conte?do de qu?mica, intentando envolver o educando no processo de aprendizagem de modo dial?gico, na busca de torn?-lo mais aut?nomo. Tamb?m tenta auxiliar os educadores em sua atua??o profissional. Para tanto, nos baseamos em aportes te?ricos que sustentam nossa percep??o, como as dificuldades de aprendizagem e alguns pressupostos do educador Paulo Freire que fundamentam a pr?tica educativa problematizadora-dial?gica. A din?mica dos Tr?s Momentos Pedag?gicos de Delizoicov, foi o referencial te?rico-metodol?gico da sequ?ncia de atividades de uma unidade did?tica para o ensino de ?cidos graxos e gorduras. A proposta foi implementada durante o segundo semestre de 2015, no Centro de Educa??o de Jovens e Adultos Professor Felipe Guerra, com uma turma do n?vel de ensino m?dio, na modalidade EJA. Quanto a abordagem do problema de estudo, buscamos seguir alguns dos pressupostos da pesquisa qualitativa, que fez uso dos instrumentos question?rio, observa??o e documentos, que foram as atividades que compunham a proposta de ensino e o projeto pedag?gico da escola. As considera??es que tecemos ante as respostas obtidas, foi a percept?vel mudan?a qualitativa na postura dos educandos, buscando participar das discuss?es, trazendo sua percep??o sobre os conte?dos qu?micos trabalhados, se envolvendo dialogicamente na constru??o de seus conhecimentos. / The systematized knowledge that is given to students at school, usually does not go beyond this space. These are consequences of an educational transmission / reception approach, which is often insufficient for contextualisation. Therefore, the utility of these knowledge is restricted to the reproduction of what has been said by the teacher. This ends up putting the students as mere spectators in the production of knowledge. Rethinking and proposing interventions in the role that each individual involved in the teaching and learning process presents, is a constant need, given the recurring changes in educational goals. This study tried to implement a proposal of teaching of chemical content, trying to involve the learner in the process of learning in a dialogical way, in the quest to make it more autonomous. It also tries to help educators in their professional activities. For that, we base ourselves on theoretical contributions that support our perception, such as the learning difficulties and some assumptions of the educator Paulo Freire that base the educational practice problematizadora-dialogical. The dynamics of Delizoicov's Three Pedagogical Moments was the theoretical-methodological reference of the sequence of activities of a didactic unit for the teaching of fatty acids and fats. The proposal was implemented during the second semester of 2015, in the Youth and Adult Education Center Professor Felipe Guerra, with a high school class, in the EJA modality. Regarding the approach to the study problem, we sought to follow some of the assumptions of the qualitative research, which used the questionnaire, observation and documents instruments, which were the activities that made up the teaching proposal and the pedagogical project of the school. The considerations we made in response to the answers were the perceptible qualitative change in the students' posture, seeking to participate in the discussions, bringing their perception about the chemical contents worked, and becoming involved in the construction of their knowledge.