Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-01-04T20:02:52Z No. of bitstreams: 1 AnaPaulaDaSilvaPeres_TESE.pdf: 6039953 bytes, checksum: dab3721993c73bd25b03fa484535a768 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-01-05T20:52:08Z (GMT) No. of bitstreams: 1 AnaPaulaDaSilvaPeres_TESE.pdf: 6039953 bytes, checksum: dab3721993c73bd25b03fa484535a768 (MD5) / Made available in DSpace on 2016-01-05T20:52:08Z (GMT). No. of bitstreams: 1 AnaPaulaDaSilvaPeres_TESE.pdf: 6039953 bytes, checksum: dab3721993c73bd25b03fa484535a768 (MD5) Previous issue date: 2014-09-08 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Nos ?ltimos anos, transportadores s?lidos de oxig?nio adequados t?m sido desenvolvidos para serem utilizados em diferentes processos de Recircula??o Qu?mica. O sucesso desta tecnologia est? diretamente relacionado com a reatividade qu?mica e a capacidade de armazenamento de oxig?nio do transportador. Desta forma, a pesquisa no desenvolvimento de novos materiais que possam ser aplicados ao processo torna-se de fundamental import?ncia. Entre os poss?veis candidatos est?o os transportadores baseados em n?quel e cobre por apresentarem propriedades termodin?micas favor?veis. Neste trabalho, aluminatos do tipo MAl2O4 (M=Mg e Ca) e M0,9B0,1Al2O4 (B=Ni e Cu) usados como suportes, foram sintetizados pela rea??o de combust?o assistida por microondas e calcinados a 900?C/2h. Em seguida, os suportes foram impregnados com 10% (m/m) de n?quel ou cobre e, posteriormente calcinados a 600?C/2h para obten??o dos transportadores s?lidos de oxig?nio, que foram caracterizados por Difra??o de raios X (DRX), Microscopia eletr?nica de varredura (MEV) e Redu??o a temperatura programada (RTP). Rea??es simulando o processo de combust?o por recircula??o qu?mica foram realizados atrav?s de ciclos de redu??o/oxida??o, com o objetivo de avaliar a reatividade dos transportadores. A an?lise de DRX mostrou picos de difra??o de estruturas tipo espin?lio. Nos suportes dopados n?o foram verificadas a presen?a de fases secund?rias, sugerindo que todo o metal foi incorporado ? estrutura do espin?lio. Nos transportadores s?lidos de oxig?nio, as fases NiO e CuO foram observadas ap?s a impregna??o das fases ativas sobre os diferentes suportes. Os resultados das avalia??es dos ciclos qu?micos de redu??o/oxida??o revelaram que os TSO?s impregnados com n?quel em diferentes suportes mostraram-se mais ativos, sendo potenciais candidatos para a aplica??o na tecnologia de Recircula??o Qu?mica. / In recent years, solid carriers suitable oxygen have been developed for use in different chemical processes recirculation. The success of this technology is directly related to the chemical reactivity and the oxygen storage capacity of the carrier. Thus, research into the development of new materials that can be applied to the process becomes extremely important. Possible candidates are the carriers based on nickel and copper for presenting favorable thermodynamic properties. In this work, aluminates type MAl2O4 (M = Mg and Ca) and M0,9B0,1Al2O4 (B = Ni and Cu) that are used as supports were synthesized by combustion reactions assisted by microwave and calcined at 900?C/2h. Then, the carriers were impregnated with 10% (m/m) of nickel or copper, and subsequently calcined at 600?C/2h to obtain the solid oxygen carriers, which were characterized by X-ray diffraction (XRD) Microscopy scanning electron microscopy (SEM) and temperature programmed reduction (TPR). Reactions simulating the combustion process by chemical recirculation were performed by cycles reduction/oxidation, in order to evaluate the reactivity of carriers. XRD analysis revealed diffraction peaks of the spinel type structures. In the doped substrates were verified the presence of secondary phases, suggesting that all the metal was incorporated into the spinel structure. In solid oxygen carriers, the NiO and CuO phases were observed after impregnation of active phases on different media. The results of evaluations of chemical cycles reduction/oxidation revealed that TSO's impregnated with nickel in various media were more active and are potential candidates for use in the chemical recirculation technology

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-03-03T20:05:49Z No. of bitstreams: 1 RenatoAndradeDosSantos_DISSERT.pdf: 954729 bytes, checksum: 7a979c335c0dd2d7d260944c7ebb2136 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-03-07T23:54:53Z (GMT) No. of bitstreams: 1 RenatoAndradeDosSantos_DISSERT.pdf: 954729 bytes, checksum: 7a979c335c0dd2d7d260944c7ebb2136 (MD5) / Made available in DSpace on 2016-03-07T23:54:53Z (GMT). No. of bitstreams: 1 RenatoAndradeDosSantos_DISSERT.pdf: 954729 bytes, checksum: 7a979c335c0dd2d7d260944c7ebb2136 (MD5) Previous issue date: 2014-08-25 / Com o objetivo de avaliar o efeito dos n?veis de caldo de cana de a??car desidratado (CCD) (0,0; 1,5; 3,0 e 4,5%) na ra??o de codornas europ?ias (Coturnix coturnix coturnix) sobre o desempenho, caracter?stica de carca?a e ?ndices econ?micos aos 22 dias de idade, 192 codornas de corte, foram distribu?das em delineamento inteiramente casualizado com quatro tratamentos e seis repeti??es de oito aves por unidade experimental. N?o houve diferen?a significativa para o desempenho das codornas em nenhum dos per?odos avaliados. Houve efeito quadr?tico dos n?veis de CCD sobre o peso da carca?a (y=173,71 + 4,2767x - 1,2644x?, R? = 0,99), coxa mais sobre-coxa (y = 36,055 + 1,1263x - 0,2256x?, R? = 0,91) e gordura abdominal (y = 3,3295 - 0,8903x + 0,19x2 , R? = 0,97) onde os n?veis ?timos estimados foram 1,69; 2,50 e 2,34%, respectivamente. Houve efeito linear decrescente dos n?veis de CCD sobre o peso de peito com pele (y = 66,267 - 0,5653x, R? = 0,83) e sem pele (y = 60,286 - 0,7193x, R? = 0,58). Na an?lise econ?mica, pode-se observar maior lucro ao produtor com a utiliza??o da ra??o convencional. Entretanto, entre os n?veis de inclus?o de caldo de cana observa-se que o n?vel 1,5% de CCD obteve os melhores resultados na an?lise econ?mica, obtendo apenas uma diferen?a de margem bruta relativa de 0,47% em rela??o ao convencional. Recomenda-se 1,69 e 2,50 e 2,34% de CCD para maior peso de carca?a, peso de coxa+sobrecoxa e menor porcentagem de gordura abdominal de codornas de corte, respectivamente. / In order to evaluate the effect of levels of dehydrated cane juice sugar (DCJS) (0.0, 1.5, 3.0 and 4.5%) in the diet of European quail (Coturnix coturnix coturnix) on performance on performance, carcass characteristics and economical at 22 days of age indices, 192 quails cutting, were distributed in a completely randomized design with four treatments and six replicates of eight birds each There was no significant difference to the performance of quail in any of the periods. Quadratic effects of levels of DCJS on carcass weight (y = 173.71 + 4.2767x ? 1.2644x?, R? = 0.99), thigh-thigh more about (y = 36,055 + 1,1263x ? 0,2256x?, R? = 0.91) and abdominal fat (y = 3,3295 - + 0.8903x 0,19x2, R ? = 0,97) where the optimum levels were estimated 1,69; 2.50 and 2.34%, respectively. There was a linear effect descending of DCJS levels on weight breast with skin (y = 66.267 ? 0.5653x, R? = 0.83) and without skin (y = 60.286 ? 0.7193x, R? = 0.58). In economic analysis, one can observe higher profit to the producer with the use of conventional feed. However, between the levels of inclusion of sugar cane juice is observed that the level of 1.5% DCJS obtained the best results in economic analysis, obtaining only a difference of relative gross margin of 0.47% compared to conventional. It is recommended 1.69 and 2.50% DCJS for higher carcass, thigh + drumstick weight and lower percentage of abdominal fat quails, respectively.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-03-31T22:25:53Z No. of bitstreams: 1 JoaoPauloDeFreitasGrilo_DISSERT.pdf: 2371966 bytes, checksum: df286c50ea1a146c8169f0dc3c57c7f5 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-04-01T23:19:59Z (GMT) No. of bitstreams: 1 JoaoPauloDeFreitasGrilo_DISSERT.pdf: 2371966 bytes, checksum: df286c50ea1a146c8169f0dc3c57c7f5 (MD5) / Made available in DSpace on 2016-04-01T23:19:59Z (GMT). No. of bitstreams: 1 JoaoPauloDeFreitasGrilo_DISSERT.pdf: 2371966 bytes, checksum: df286c50ea1a146c8169f0dc3c57c7f5 (MD5) Previous issue date: 2015-06-25 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Comp?sitos NiO-C0.9Gd0.1O1.95 (NiO-CGO), um dos materiais mais utilizado para fabrica??o de anodos de C?lulas a Combust?veis de ?xido S?lido (CCOS) atualmente, foram obtidos por uma rota qu?mica que consiste na mistura das solu??es precursoras das fases NiO e CGO previamente obtidas pelo m?todo Pechini, com percentual m?ssico da fase NiO variando entre 0 e 100 %. Os nanop?s como obtidos foram caracterizados por t?cnicas de an?lise t?rmica (termogravimetria e Calorimetria Diferencial Explorat?ria) e os materiais calcinados foram estudados por difratometria de raios X (DRX). Amostras sinterizadas entre 1400 e 1500 ?C por 4 h foram caracterizadas pelo m?todo de Arquimedes. Os efeitos da composi??o relativa na microestrutura e propriedades el?tricas (condutividade e energia de ativa??o) de comp?sitos sinterizados a 1500 ?C foram investigados por microscopia eletr?nica e espectroscopia de imped?ncia (entre 300 e 650 ?C em ar). O refinamento dos dados de DRX indicaram que os p?s s?o ultrafinos e que o tamanho do cristalito da fase CGO tende a diminuir com o aumento de teor de NiO. De maneira semelhante, o cristalito da fase NiO tende a diminuir com o aumento da concentra??o de CGO, principalmente acima de 50% em massa de CGO. A an?lise por Arquimedes evidencia uma varia??o na densidade relativa em fun??o do teor de NiO. Densidades relativas acima de 95% foram obtidas em comp?sitos contendo a partir de 50 % em massa de NiO e sinterizados entre 1450 e 1500 ?C. Os resultados de microscopia e espectroscopia de imped?ncia indicam que a partir de 30 - 40 % de NiO h? aumento do n?mero de contatos NiO-NiO, ativando o mecanismo de condu??o eletr?nica que governa o processo de condu??o a baixas temperaturas (300-500 ?C). Por outro lado, com o aumento da temperatura de medida a mobilidade das vac?ncias de oxig?nio torna-se maior que a dos buracos eletr?nicos do NiO, como resultado, a condutividade de alta temperatura (550 - 650 ?C) em comp?sitos contendo at? 30-40% de NiO ? inferior ? do CGO. Varia??es na energia de ativa??o confirmam mudan?a do mecanismo de condu??o com o aumento do teor de NiO. O comp?sito contendo 50 % em massa de cada fase apresenta condutividade de 19 mS/cm a 650 ?C (pouco superior a 13 mS/cm encontrada para o CGO) e energia de ativa??o 0,49 eV. / Composite NiO-C0.9Gd0.1O1.95 (NiO-GDC), one of the materials most used for the manufacture of anodes of Cells Solid Oxide Fuel (SOFC) currently, were obtained by a chemical route which consists in mixing the precursor solution of NiO and CGO phases obtained previously by the Pechini method. The nanopowders as-obtained were characterized by thermal analysis techniques (thermogravimetry and Differential Scanning Calorimetry) and calcined materials were evaluated by X-ray diffraction (XRD). Samples sintered between 1400 and 1500 ? C for 4 h were characterized by Archimedes method. The effects of the composition on the microstructure and electrical properties (conductivity and activation energy) of the composites sintered at 1500 ? C were investigated by electron microscopy and impedance spectroscopy (between 300 and 650 ? C in air). The refinement of the XRD data indicated that the powders are ultrafine and the crystallite size of the CGO phase decreases with increasing content of NiO. Similarly, the crystallite of the NiO phase tends to decrease with increasing concentration of CGO, especially above 50 wt % CGO. Analysis by Archimedes shows a variation in relative density due to the NiO content. Densities above 95% were obtained in samples containing from 50 wt % NiO and sintered between 1450 and 1500 ?C. The results of microscopy and impedance spectroscopy indicate that from 30-40 wt.% NiO there is an increase in the number of contacts NiO - NiO, activating the electronic conduction mechanism which governs the process of conducting at low temperatures (300 - 500 ?C). On the other hand, with increasing the measuring temperature the mobility of oxygen vacancies becomes larger than that of the electronic holes of NiO, as a result, the high temperature conductivity (500-650 ? C) in composites containing up to 30-40 wt.% of NiO is lower than that of CGO. Variations in activation energy confirm change of conduction mechanism with the increase of the NiO content. The composite containing 50 wt. % of each phase shows conductivity of 19 mS/cm at 650 ?C (slightly higher than 13 mS/cm found for CGO) and activation energy of 0.49 eV.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-05-03T22:43:01Z No. of bitstreams: 1 JussaraAparecidaDeMeloGondimFerreira_TESE.pdf: 2041895 bytes, checksum: 3a2d57c4ba7978017dd1b0ac8c752ef4 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-05-04T23:33:17Z (GMT) No. of bitstreams: 1 JussaraAparecidaDeMeloGondimFerreira_TESE.pdf: 2041895 bytes, checksum: 3a2d57c4ba7978017dd1b0ac8c752ef4 (MD5) / Made available in DSpace on 2016-05-04T23:33:17Z (GMT). No. of bitstreams: 1 JussaraAparecidaDeMeloGondimFerreira_TESE.pdf: 2041895 bytes, checksum: 3a2d57c4ba7978017dd1b0ac8c752ef4 (MD5) Previous issue date: 2015-02-26 / O conte?do de solu??es ? considerado muito importante para a forma??o do qu?mico, pois a maioria das rea??es ocorre em meio aquoso, sendo tamb?m necess?rio para o entendimento de outros conte?dos como transforma??es qu?micas, eletroqu?mica e equil?brio qu?mico. No entanto, constata-se que muitos alunos apresentam dificuldades que envolvem o conte?do de solu??es, como transitar entre os n?veis de conhecimento macro-submicrosc?pico e solucionar problemas quantitativos que exigem o estabelecimento de rela??es estequiom?tricas. A tese defendida considera que o uso de estrat?gias de ensino contextualizadas, estruturadas na forma de um minicurso, sobre alguns conte?dos considerados de maior dificuldade de compreens?o relacionados ao estudo de solu??es, pode favorecer o aprendizado do p?blico-alvo, o alunado do curso de licenciatura em qu?mica modalidade a dist?ncia da UFRN, atrav?s da reflex?o e conhecimento de suas pr?prias dificuldades, al?m de proporcionar motiva??o e participa??o ativa. Assim, foram identificadas as dificuldades de aprendizagem relacionadas ao conte?do de solu??es atrav?s do levantamento bibliogr?fico; analisada, por meio de um roteiro adaptado do PNLEM, a abordagem do conte?do de solu??es presente no material did?tico impresso utilizado pelo p?blico-alvo; e planejado e ministrado um minicurso constando de uma sequ?ncia de atividades contextualizadas relacionadas ao conte?do de solu??es, tais como: apresenta??o de v?deo, aula expositiva dialogada, aplica??o de question?rios, exerc?cios e experimento. Os participantes do minicurso apresentaram algumas dificuldades de aprendizagem, como compreender conceitos como composto, ?on, carga, entropia e solubilidade, identificar a carga do ?on, interpretar enunciados, decodificar tabelas, utilizar a linguagem qu?mica, realizar c?lculos matem?ticos e utilizar unidades de concentra??o. Para trabalhar essas dificuldades, os alunos foram estimulados a expor, questionar e testar suas ideias sobre o fen?meno em estudo, possibilitando aprender com os pr?prios erros e refletir sobre a estrat?gia de organiza??o dos modelos cient?ficos explicativos que utilizam. Desse modo, as atividades e as informa??es sobre as dificuldades de aprendizagem apresentadas neste trabalho precisam ser objeto de reflex?o cr?tica, pois podem ajudar os alunos no processo de aquisi??o do conhecimento sobre o conte?do de solu??es e os professores no planejamento de suas aulas. / The study of solutions is considered very important to chemist?s education because most of the chemical reactions occur in aqueous medium, being also required to understand other subject such as chemical changes, electrochemical and chemical balance. Nevertheless, it is noticed that many students indicate learning difficulties related to the content of solutions, how to pass among the macro-submicroscopic knowledge levels, and how to solve quantitative problems that demanding the establishment of a stoichiometric ratios. This thesis defended considers the use of contextualized teaching strategies about some subject associated to the study of solution, can foster student learning through reflection and understanding of their own difficulties, besides to provide motivation and active participation. The target group is formed by students of the undergraduate distance education with major in chemistry education of the Universidade Federal do Rio Grande do Norte (UFRN), and they were chosen because this education system is expanding and its learning difficulties publications number is reduced as well. Thus, the first methodological stage was to identify the student?s main learning difficulties associated to the study of solutions through literature sources. Next, using an adapted script of the Plano Nacional do Livro Did?tico para o Ensino M?dio (PNLEM, Textbook National Plan for High School), the approach of the content of solutions printed in educational materials used by the target group was analyzed. Afterward, a teaching unit was planned in the last methodological stage and, finally, a new teaching unite was given with a sequence of contextualized activities such as video presentation, dialogued lecture, questionnaires application, exercises, and an experiment, where the target group?s main difficulties related to learning of solution were identified. The participants of the teaching unit activities had some learning difficulties in understand concepts of compound, ion, charge, entropy and solubility, as well as to identify the ion charge, interpret statements, decode tables, use the chemical language, perform mathematical calculations and use concentration units, similar results raised in the literature sources. In order to work on these difficulties, these students were encouraged to expose, question and test their ideas about the phenomenon under study, allowing learn from their mistakes and reflect on the organization strategy of scientific explanatory models they use. Therefore, activities and information about learning difficulties presented in this thesis need to be critical reflection object, because it can help both students in the process of acquiring knowledge about the content of solutions and professors in the planning of their lessons.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-06-15T00:21:54Z No. of bitstreams: 1 ViniciusCampeloSoeiro_DISSERT.pdf: 1414998 bytes, checksum: 1ed8e56eafbeeb635d402b28f04dc255 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-06-17T23:56:05Z (GMT) No. of bitstreams: 1 ViniciusCampeloSoeiro_DISSERT.pdf: 1414998 bytes, checksum: 1ed8e56eafbeeb635d402b28f04dc255 (MD5) / Made available in DSpace on 2016-06-17T23:56:05Z (GMT). No. of bitstreams: 1 ViniciusCampeloSoeiro_DISSERT.pdf: 1414998 bytes, checksum: 1ed8e56eafbeeb635d402b28f04dc255 (MD5) Previous issue date: 2016-01-21 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPq / Glucanas s?o polissacar?deos com diversas atividades farmacol?gicas e biol?gicas descritas. Contudo, h? pouco relatos sobre as atividades das dextranas com figura??o do tipo ? (alfa). Nesse contexto, dextranas (?-D-glucanas) extra?das da bact?ria Leuconostoc mesenteroides, com massas moleculares de 10 (D10), 40 (D40) e 147 (D147) kDa e seus derivados fosforilados P10, P40 e P147 foram avaliados quanto ao seu potencial antioxidante, anticoagulante e imunomodulador pela primeira vez, com o intuito de elucidar compostos com atividades potentes e pouco t?xicas. An?lises de espectroscopia de infravermelho, composi??o monossacar?dica e dosagens qu?micas comprovaram que estas dextranas s?o o mesmo polissacar?deo, mas com massas moleculares diferentes, al?m de confirmar o sucesso da fosforila??o. Nenhuma das dextranas tem atividade anticoagulante. No teste do poder redutor verificou-se que D147 e P147 foram duas vezes mais potentes que as outras dextranas. Por outro lado, as seis amostras tiveram atividade semelhante (50%) em sequestrar o radical OH. Frente ao sequestro do ?on super?xido, apenas D10 teve uma atividade pronunciada (50%). D40 foi a ?nica dextrana nativa com a??o imunomodulat?ria, pois estimulou em dobro a prolifera??o de macr?fagos mur?nicos (RAW 264.7) e dobrou a libera??o de NO por essas c?lulas, tanto na aus?ncia como na presen?a de LPS. Al?m disso D40 teve maior atividade sequestradora (50%) de per?xido de hidrog?nio, o que fez com que ela tamb?m fosse a dextrana mais potente em inibir peroxida??o lip?dica (70%). J? P147 apresentou maior atividade quelante de ?ons ferro e cobre (~85%), al?m de aumentar o triplo a libera??o de NO na aus?ncia e na presen?a de LPS. P10 provou ser o composto mais efetivo sobre a prolifera??o de macr?fagos. Os dados indicam que dextranas com massa aproximada de 40 kDa s?o as ideais para serem utilizadas como antioxidantes e imunomoduladores, podendo ter suas atividades potencializadas com o processo de fosforila??o. Contudo, estudos futuros com D40 e outras dextranas de massa semelhante confirmar?o esta hip?tese. / Glucans are polysaccharides with different pharmacological and biological activities described. However, there are some reports about the activities of the glucan type ? (alpha). In this context, a group of ?-D-glucans called dextrans extracted from Leuconostoc mesenteroides bacteria, with molecular weights of 10 (D10), 40 (D40) and 147 (D147) kDa and their phosphorylated derivatives P10, P40 and P147, were evaluated as for their antioxidant, anticoagulant and immunomodulatory potential for the first time, in order to elucidate compounds with potent activities and low toxicity. Infrared spectroscopy analysis, monosaccharide composition and chemical dosages showed that these dextrans are the same polysaccharide, but with different molecular weights, besides confirming the success of phosphorylation. None presented with anticoagulant features. The reducing power test showed that D147 was twice as potent as other dextrans. On the other hand, all six samples showed similar activity (50%) when it came to scavenging the OH radical. To the superoxide ion scavenging, only D10 had a pronounced activity (50%). D40 was the single native dextran that presented with immunomodulatory features since it double stimulated the proliferation of murine macrophages (RAW 264.7) and double the release of nitric oxide by the cells, both in the absence and presence of lipopolysaccharides (LPS). In addition, D40 showed a greater scavenging activity (50%) for the hydrogen peroxide, which caused it to also be the more potent dextran when it came to inhibiting lipid peroxidation (70%). On other hand, P147 showed the highest iron and copper ion chelation activity (~85%). P10 proved be the most effective compound to macrophage proliferation. The results point toward dextrans with a 40 kDa weight as being ideal for antioxidant and immunomodulatory use, could be supplemented with phosphorylated derivatives. However, future studies with the D40 and other similarly dextrans are to confirm this hypothesis.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-07-20T21:51:02Z No. of bitstreams: 1 FabiaMariaGomesDeMeneses_TESE.pdf: 3548488 bytes, checksum: 82c1b49fbed074cc6175d3f6ed8fda0e (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-07-21T20:06:15Z (GMT) No. of bitstreams: 1 FabiaMariaGomesDeMeneses_TESE.pdf: 3548488 bytes, checksum: 82c1b49fbed074cc6175d3f6ed8fda0e (MD5) / Made available in DSpace on 2016-07-21T20:06:15Z (GMT). No. of bitstreams: 1 FabiaMariaGomesDeMeneses_TESE.pdf: 3548488 bytes, checksum: 82c1b49fbed074cc6175d3f6ed8fda0e (MD5) Previous issue date: 2015-10-15 / O estudo das rea??es qu?micas encontra-se entre os conte?dos mais importantes para a compreens?o da disciplina de Qu?mica. Mas ainda s?o pouco os estudos que apresentam as rea??es qu?micas como sistema complexo. A tese aqui apresentada tem como objetivo investigar, identificar e caracterizar os erros e dificuldades de aprendizagem de estudantes em rela??o as rea??es qu?micas como sistema complexo, utilizando para tanto a an?lise das respostas de 126 provas de estudantes candidatos ao curso de Licenciatura em Qu?mica, oferecido pela Universidade Federal do Rio Grande do Norte (UFRN). Foram investigados e discutidos os erros e dificuldades de aprendizagem dos par?metros ?G, Kp, Ea e do c?lculo de quantidade de subst?ncia numa rea??o qu?mica e a inter-rela??o desses par?metros no estudo das rea??es qu?mica como sistema. O trabalho classificou em n?veis de desenvolvimento a habilidade de interpretar a rea??o qu?mica como sistema. A partir de entrevistas realizadas com professores de Qu?mica, do Ensino M?dio, se determinou as raz?es a que os professores atribuem esses erros e dificuldades de aprendizagem. A aprendizagem das rea??es qu?mica no Ensino M?dio perpassa por conceitos de termoqu?mica, de cin?tica, do equil?brio e os seus aspectos quantitativos e qualitativos, esses conceitos n?o possuem uma articula??o org?nica entre si para a melhor compreens?o de como ocorre e porque ocorre uma rea??o qu?mica, o que garante a compreens?o dos sentidos das partes numa totalidade. Os resultados obtidos indicam que os estudantes n?o compreendem o conceito de ?G, Kp, Ea. Os professores n?o trabalham na perspectiva de integra??o dos conte?dos o que leva os alunos a apresentarem dificuldades e cometerem erros relacionados ao conte?do citado. O trabalho apresenta uma proposta de organiza??o dos conte?dos da Qu?mica para o Ensino M?dio como uma possibilidade de integra??o sist?mica dial?tica dos conte?dos, entendendo que essa vis?o sistem?tica, leva a importantes contribui??es com o desenvolvimento do pensamento te?rico dos alunos. A estrutura??o dos conte?dos da Qu?mica apresentado nesse trabalho, fundamenta-se no m?todo de an?lise sist?mico dial?tico funcional-estrutural desenvolvidos Reshetova (1988) e N?nez (1992). Essa tese traz contribui??es significativas para o ensino-aprendizagem de uma rea??o qu?mica como sistema complexo. / The study of chemical reactions is among the most important contents to the understanding of Chemistry discipline in basic education. However, there are still few studies about chemical reactions as a complex system because, generally, this content is presented in textbooks, taught and even researched in a fragmented form. The thesis here presented aims to investigate, identify and characterize the mistakes and learning difficulties of the students about chemical reactions as a complex system, using for that purpose the analysis of the answers of 126 exams of candidates for the bachelor?s degree in Chemistry Teaching on the entrance exam for the Federal University of Rio Grande do Norte (UFRN). The mistakes and learning difficulties about the parameters ?G?, Kp, Ea and of the calculation of the amount of substance in a chemical reaction have been identified, as well as the levels of development of the ability to interpret the chemical reaction as a system. The main theoretical source of this study is structured based on the mistakes and learning difficulties (N??EZ, RAMALHO, 2012), of the chemical reactions as complex systems (N??EZ, 1994; RESHETOVA, 1988; SANDERSON, 1968). As methodology, it was prioritized the analysis of the answers to the exams and the interview with the teachers. The results showed typical mistakes in the study of this subject, especially low levels and skill development. No student was able to integrate the different aspects in the systemic understanding of the chemical reaction. From the interviews with Chemistry teachers from High School, it was determined the reasons the teachers assign to those mistakes and learning difficulties. The interviews revealed that the teachers do not work in the perspective of integration of the contents which leads the students to present difficulties and make mistakes related to the content previously mentioned. The study presents a proposal for the organization of the contents of Chemistry discipline for High School as a possibility of a dialectic systemic integration of contents, understanding that this systematic vision, leads to important contributions to the development of the theoretical thinking of the students. We can mention as one of the conclusions of this study, the fact that the non-systemic organization of contents do not favor this kind of thinking in students.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-07-25T19:35:29Z No. of bitstreams: 1 KeylaThayrinneOliveiraCoimbra_DISSERT.pdf: 21184106 bytes, checksum: cd5ec307de2601ec684062fb512f9165 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-07-29T00:13:31Z (GMT) No. of bitstreams: 1 KeylaThayrinneOliveiraCoimbra_DISSERT.pdf: 21184106 bytes, checksum: cd5ec307de2601ec684062fb512f9165 (MD5) / Made available in DSpace on 2016-07-29T00:13:31Z (GMT). No. of bitstreams: 1 KeylaThayrinneOliveiraCoimbra_DISSERT.pdf: 21184106 bytes, checksum: cd5ec307de2601ec684062fb512f9165 (MD5) Previous issue date: 2015-08-25 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / O plut?o Bom Jardim de Goi?s (PBJG) ? um corpo de geometria semi-circular, situado na por??o central da Prov?ncia Tocantins, intrusivo em ortognaisses e metassupracrustais do Arco Magm?tico Aren?polis. Estas metasupracrustais apresentam um bandamento / xistosidade de ?ngulo baixo a moderado, definido por micas, andalusita, silimanita e cordierita, caracterizando um metamorfismo na f?cies anfibolito. Tal estrutura ? truncada pela coloca??o das rochas do PBJG. O car?ter abrupto dos contatos e a aus?ncia de estruturas d?cteis demonstram que a intrus?o se deu em crosta relativamente fria. Em termos petrogr?ficos, o plut?o comp?e-se de monzodioritos, tonalitos e granodioritos, seguindo a trajet?ria evolutiva c?lcio-alcalina de pot?ssio baixo a intermedi?rio. As rochas do PBJG possuem hornblenda e biotita como fases m?ficas principais, al?m da ocorr?ncia subordinada de clinopirox?nio, titanita, ep?doto e opacos. Diques tardios de leucogranito cont?m apenas biotita como mineral acess?rio relevante. Uma data??o U-Pb em zirc?o do monzodiorito forneceu uma idade de 550?12 Ma (MSWD = 1,06). Dados litogeoqu?micos e de qu?mica mineral sugerem que as rochas em foco s?o c?lcio-alcalinas, tendo evolu?do por cristaliza??o fracionada de minerais c?lcicos e ferro-magnesianos, sob condi??es de alta fugacidade de oxig?nio. Utilizando o geoterm?metro do par anfib?lio-plagiocl?sio e o geobar?metro de Al em anfib?lio, foram determinadas temperaturas e press?es em torno de 692-791 ?C e 2,4 e 5,0 kbar para a intrus?o do PBJG, o que ? corroborado por associa??es metam?rficas pr?-existentes nas encaixantes. As caracter?sticas geol?gicas, geoqu?micas e a geocronologia do PBJG demonstram sua natureza p?s-tect?nica ou p?s-colisional, com coloca??o em crosta j? soerguida e relativamente fria, ao final da orog?nese brasiliana nesta por??o da Prov?ncia Tocantins. / The Bom Jardim de Goi?s Pluton (PBJG) is a semi-circular body, located in the central portion of the Tocantins Province, intrusive into orthogneisses and metassupracrustals of the Aren?polis Magmatic Arc. These metasupracrustals present a low to moderate dipping banding or schistosity, have a low to moderate angle of banding / foliation, defined by mica, andalusite and sillimanite and cordierite, which characterize an amphibolite facies metamorphism. This structure is crosscut by the emplacement of the PBJG rocks. The abrupt nature of the contacts and the absence of ductile structures indicate that the intrusion took place in a relatively cold crust. Under petrographic grounds, the pluton consists mainly of monzodiorites, tonalite and granodiorite, following the low to medium-K calk-alkaline alkaline trend. Rocks of the PBJG have hornblende and biotite as the main mafic phases, besides subordinate clinopyroxene, titanite, epidote and opaque. Late dikes of leucogranite contain only mineral biotite as relevant accessory mineral. One U-Pb zircon dating of a monzodiorite yielded an age of 550 ? 12 Ma (MSWD = 1.06). Whole-rock and mineral chemistry suggest that the studied rocks are calc-alkaline, having evolved by fractional crystallization of Ca- and Fe-Mg minerals under high oxygen fugacity. Using the amphibole-plagioclase geothermometer and the Al-in amphibole geobarometer, we calculate temperatures and pressures of, respectively, 692-791 ?C e 2.4-5.0 kbar for the intrusion of the PBJG, which is corroborated by previous metamorphic assemblages in the country rocks. The geological, geochemical and geochronological features of PBJG demonstrate their post-tectonic or post-collisional nature, with emplacement into an already uplifted and relatively cool crust at the end of brasiliano orogeny in this portion of the Tocantins Province.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-07-25T23:07:30Z No. of bitstreams: 1 KahenaDeQuevedoFlorentin_DISSERT.pdf: 2361429 bytes, checksum: dc742ce59ccfacea57721d908c3a033e (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-08-04T20:32:42Z (GMT) No. of bitstreams: 1 KahenaDeQuevedoFlorentin_DISSERT.pdf: 2361429 bytes, checksum: dc742ce59ccfacea57721d908c3a033e (MD5) / Made available in DSpace on 2016-08-04T20:32:42Z (GMT). No. of bitstreams: 1 KahenaDeQuevedoFlorentin_DISSERT.pdf: 2361429 bytes, checksum: dc742ce59ccfacea57721d908c3a033e (MD5) Previous issue date: 2015-10-28 / Alginate is a linear polymer compound of D-mannuronic acid(M) linked (1 ? 4) at its epimer in C-5 of L-guluronic acid (G). An alginate was isolated and partially purified from brown seaweed D. delicatula (DYN). DYN was chemically sufated (DYS). DYS showed 22% of sulfation and the rate of total sugars was around 66 and 59% for DYN and DYS respectively. DYN DYS and showed a ratio M G of 0.86 and 1.1, respectively. IR signals at 1221cm-1 confirmed the sulfation of DYS. DYN presented anticoagulant activity about intrinsic coagulation pathway, while DYS did not alter the clotting times for aPTT and PT. DYN and DYS also showed antioxidant properties especially ferric chelation where DYN reached about 97% and the OH sequestration where both averaged 85%. In 3T3 cells, DYN indicated proliferation in 24h and 48h of incubation and no cytotoxicity. For tumor lines HeLa and b16, and DYN and DYS decreased significantly the cell viability, especially after 48 hours (about 71% of inhibition). Given the results obtained in this study, it is clear that the sulfation is not decisive for the activity of D. delicatula alginate. In general, DYS and DYN shown as potential compounds to be used pharmacologically, and also in the food industry for revealing be great antioxidant. / Marine algae are rich sources of various structural compounds which recently has been increasingly studied as a new source of bioactive substances. The alginate, as come as fucans, are considered the main acidic polysaccharides found in brown seaweed. This molecule consists a linear natural polysaccharide, non-sulfated, and presents monosaccharides: acid ?-D-mannuronic (M) and ?-L-guluronic acid (G); in a vast amount compositions and threads. Alginate has been widely applied in food and pharmaceutical industries because of its ability to retain water, forming films and gels as well as thickening, stabilizing and form emulsions. In this work we aimed to extract, structurally characterize, compare and analyze the possible pharmacological activities of native alginate molecule obtained from brown seaweed Dyctiopteris delicatula (DYN), and its chemically sulfated derivative (DYS). The alginate structure and composition molecule can be proven through chemical dosing, that showed low protein contamination and high sugar level, existence and separation of M and G blocks in the descending paper chromatography, infrared spectroscopy and nuclear magnetic resonance. Molecule sulfation was proven with sulphate dosage, resulting in 28.56% sulphate in molecule; electrophoresis, verify metachromasia with toluidine blue; and infrared spectroscopy, that showed a characteristic band at 1221cm-1 corresponding a sulfate group vibration. For the pharmacological activities the tests was: antioxidant activity, changes in cell function (MTT test) and anticoagulant test. In the antioxidant activity we observed that DYN showed better results in the kidnapping of hydroxyl radicals and ferric chelation compared to DYS, this had the best result in the total antioxidant capacity. Both showed similar activity in reducing power and the kidnapping radicals DPPH. In MTT test DYN and DYS had not proliferative and cytotoxic activity in fibroblast cells (3T3) and showed antiproliferative and cytotoxic activity in cancer cell lines HeLa and B16 melanoma. In anticoagulant assay DYN showed good activity in the intrinsic pathway of blood coagulation, and a small activity in the extrinsic pathway, in the other hand DYS showed only a very small activity in the extrinsic pathway, but cannot come to be regarded as an anticoagulant agent. From these results it can be concluded that the alginate was extracted and sulfated, revealing a potential compound to be used in the pharmaceutical industry as an anticoagulant agent, antioxidant and antitumor and the sulfation has not been conclusively important to performance in the tested pharmacological activities

Made available in DSpace on 2014-12-17T15:01:24Z (GMT). No. of bitstreams: 1 CelynaKOS_DISSERT.pdf: 1291622 bytes, checksum: 6aba20d221ab35537c160d478e6ac5f7 (MD5) Previous issue date: 2010-12-16 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The soil contamination with petroleum is one of the major concern of industries operating in the field and also of environmental agencies. The petroleum consists mainly of alkanes and aromatic hydrocarbons. The most common examples of hydrocarbons polyaromatic are: naphthalene, anthracene, phenanthrene, benzopyrene and their various isomers. These substances cause adverse effects on human and the environment. Thus, the main objective of this work is to study the advanced oxidation process using the oxidant potassium permanganate (KMnO4) for remediation of soils contaminated with two polyaromatic hydrocarbons (PAHs): anthracene and phenanthrene. This study was conducted at bench scale, where the first stage was at batch experiment, using the variables: the time and oxidant dosage in the soil. The second stage was the remediation conducted in continous by a fix column, to this stage, the only variable was remediation time. The concentration of oxidant in this stage was based on the best result obtained in the tests at batch, 2,464 mg / L. The results of degradation these contaminants were satisfactory, at the following dosages and time: (a) 5g of oxidant per kg soil for 48 hours, it was obtained residual contaminants 28 mg phenanthrene and 1.25 mg anthracene per kg of soil and (b) for 7g of oxidant per kg soil in 48 hours remaining 24 mg phenanthrene and anthracene 0.77 mg per kg soil, and therefore below the intervention limit residential and industrial proposed by the State Company of Environmental Sao Paulo (CETESB) / A contamina??o de solo com petr?leo ? uma das grandes preocupa??es das ind?strias que atuam no ramo e tamb?m dos ?rg?os ambientais. O petr?leo ? constitu?do basicamente por hidrocarbonetos alcanos e arom?ticos. Os exemplos mais comuns dos hidrocarbonetos poliarom?ticos s?o: naftaleno, antraceno, fenantreno, benzopireno e seus v?rios is?meros. Estas subst?ncias apresentam efeitos nocivos ao ser humano e ao meio ambiente. Logo, este trabalho tem como principal objetivo, estudar o processo de oxida??o avan?ada, utilizando o oxidante permanganato de pot?ssio (KMnO4), na remedia??o de solos contaminados com dois hidrocarbonetos poliarom?ticos (HPAs): antraceno e fenantreno. Este estudo foi realizado em escala de bancada, sendo a primeira etapa realizada experimentos em batelada, utilizando as vari?veis: tempo de remedia??o e dosagem do oxidante. Na segunda etapa, a remedia??o foi realizada em regime cont?nuo utilizando coluna de leito fixo, para esta etapa a ?nica vari?vel foi tempo de remedia??o. A concentra??o do oxidante nesta etapa, foi baseada no melhor resultado obtido nos ensaios em batelada, 2464 mg/L. Os resultados da degrada??o destes contaminantes foram satisfat?rios, nas seguintes dosagens de oxidante e tempo de remedia??o: (a) 5g de oxidante por kg de solo em 48 horas, foram obtidos contaminantes residuais de 28 mg de fenantreno e 1,25 mg de antraceno por kg de solo e (b) para 7g de oxidante por kg de solo em 48 horas restaram 24 mg de fenantreno e 0,77 mg de antraceno por kg de solo, ficando abaixo dos valores de interven??o residencial e industrial propostos pela Companhia Ambiental do Estado de S?o Paulo (CETESB)

Made available in DSpace on 2014-12-17T15:15:04Z (GMT). No. of bitstreams: 1 BrunoLeonardoCM_tese.pdf: 1145565 bytes, checksum: f87b60fc5eccfa3202f94947ce740090 (MD5) Previous issue date: 2007-08-06 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Galactic stellar clusters have a great variety of physical properties that make valuable probes of stellar and galactic chemical evolution. Current studies show a discrepancy between the standard evolutionary models and observations, mainly considering the level of mixing and convective dilution of light elements, as well as to the evolution of the angular momentum. In order to better settle some of these properties, we present a detailed spectroscopic analysis of 28 evolved stars, from the turn-off to the RGB, belonging to the stellar open cluster M67. The observations were performed using UVES+FLAMES at VLT/UT2. We determined stellar parameters and metallicity from LTE analysis of Fe I and Fe II lines between 420 1100 nm. The Li abundance was obtained using the line at 6707.78 ˚A, for the whole sample of stars. The Li abundances of evolved stars of M67 present a gradual decreasing when decreasing the effective temperature. The Li dilution factor for giant stars of M67 with Teff ∼ 4350K is at least 2300 times greater than that predicted by standard theory for single field giant stars. The Li abundance as a function of rotation exhibits a good correlation for evolved stars of M67, with a much smaller dispersion than the field evolved stars. The mass and the age seem to be some of the parameters that influence this connection. We discovered a Li-rich subgiant star in M67 (S1242). It is member of a spectroscopic binary system with a high eccentricity. Its Li abundance is 2.7, the highest Li content ever measured for an evolved star in M67. Two possibilities could explain this anomalous Li content: (i) preservation of the Li at the post turn off stage due to tidal effects, or (ii) an efficient dredge-up of Li, hidden below the convective zone by atomic diffusion occurring in the post turn off stage. We also study the evolution of the angular momentum for the evolved stars in M67. The results are in agreement with previous studies dedicated to evolved stars of this cluster, where stars in the same region of the CM-diagram have quite similar rotations, but with values that indicate an extra breaking along the main sequence. Finally, we analize the distributions of the average rotational velocity and of the average Li abundance as a function of age. With relation to the average Li abundances, stars in clusters and field stars present the same type of exponencial decay law t−β. Such decay is observed for ages lesser than 2 Gyr. From this age, is observed that the average Li abundance remain constant, differently of the one observed in the rotation age connection, where the average rotational velocity decreases slowly with age / Os aglomerados estelares possuem uma grande variedade de propriedades f?sicas que os tornam provas valiosas da evolu??o estelar e gal?ctica. Estudos recentes mostram uma discrep?ncia entre o modelo padr?o de evolu??o e as observa??es, principalmente com rela??o ao n?vel de mistura e dilui??o convectiva de elementos leves, bem como na evolu??o do momentum angular. Para melhor estabelecer algumas destas propriedades, apresentamos uma an?lise espectrosc?pica detalhada de 28 estrelas evolu?das, do turn off ao ramo das gigantes, pertencentes ao aglomerado estelar aberto M67. As observa??es foram feitas com o espectr?grafo UVES+FLAMES no VLT/U2. Determinamos os par?metros estelares e a metalicidade a partir de an?lises em ETL de linhas de Fe I e Fe II entre 420 1100 nm. A abund?ncia de 7Li foi obtida a partir da linha do l?tio em 6707.78 ˚A, para todas as estrelas da amostra. A abund?ncia de 7Li apresenta, para as estrelas evolu?das de M67, um gradual decrescimento na medida em que a temperatura efetiva diminui. O fator de dilui??o do Li para estrelas gigantes de M67 com Tef ∼ 4350K ? pelo menos 2300 vezes superior ao previsto pela teoria padr?o para estrelas gigantes simples de campo. A abund?ncia de Li em fun??o da rota??o apresenta uma boa correla??o para as estrelas evolu?das de M67, com uma dispers?o muito menor do que para as estrelas de campo. A massa e a idade parecem ser alguns dos par?metros que influenciam tal conex?o. Um outro resultado interessante de nosso trabalho diz respeito ? descoberta de uma estrela subgigante rica em Li de M67 (S1242). Ela ? membro de um sistema bin?rio espectrosc?pico com alta excentricidade. Sua abund?ncia de Li ? 2,7, a maior at? ent?o medida em uma estrela evolu?da de M67. Duas possibilidades podem explicar este conte?do an?malo de Li: (i) preserva??o do Li nos est?gios p?s turn off devido a efeitos de mar? gravitacional, ou (ii) uma dragagem eficiente do Li presente nas camadas abaixo da zona iii convectiva atrav?s de difus?o at?mica em est?gios p?s-turn off. Tamb?m estudamos a rela??o do 7Li com a evolu??o do momentum angular em estrelas evolu?das de M67. Os resultados encontrados est?o em acordo com estudos anteriores dedicados a estrelas evolu?das deste aglomerado, onde as estrelas de uma mesma regi?o do diagrama CM possuem rota??es bastante similares, por?m com valores que apontam para uma desacelera??o extra ao longo da seq??ncia principal. Por fim, analisamos as distribui??es da velocidade rotacional m?dia e da abund?ncia m?dia de Li em fun??o da idade. Com rela??o a abund?ncia m?dia de Li, tanto as estrelas em aglomerados quanto as estrelas de campo, apresentam um mesmo decrescimento exponencial do tipo t−β. Tal decrescimento s? ? observado para idades menores do que 2 Giga-anos. A partir desta idade, observa-se que a abund?ncia m?dia de Li mant?m-se constante, diferentemente do que ? observado na conex?o rota??o idade, onde a velocidade rotacional m?dia decresce lentamente com a idade