Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-08-26T23:16:09Z No. of bitstreams: 1 MonickarlaTeixeiraPegadoDaSilva_DISSERT.pdf: 2972749 bytes, checksum: 333ef217ee5461818b38fff8de7cfdeb (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-08-31T00:12:48Z (GMT) No. of bitstreams: 1 MonickarlaTeixeiraPegadoDaSilva_DISSERT.pdf: 2972749 bytes, checksum: 333ef217ee5461818b38fff8de7cfdeb (MD5) / Made available in DSpace on 2016-08-31T00:12:48Z (GMT). No. of bitstreams: 1 MonickarlaTeixeiraPegadoDaSilva_DISSERT.pdf: 2972749 bytes, checksum: 333ef217ee5461818b38fff8de7cfdeb (MD5) Previous issue date: 2016-02-23 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Suportes catal?ticos ? base de ?xido de alum?nio foram sintetizados pelo m?todo e esferas h?bridas utilizando carboximetilcelulose (CMC) como precursor org?nico (template) e nitrato de alum?nio como precursor inorg?nico. As caracteriza??es foram realizadas por an?lises de termogravimetria (TG), difra??o de raios-X (DRX), espectroscopia no infravermelho por transformada de fourier (FTIR), microscopia eletr?nica de varredura (MEV) e fisissor??o N2. Os materiais sintetizados foram testados na rea??o de convers?o do glicerol em fase g?s. Os estudos da s?ntese indicaram que as caracter?sticas do biopol?mero (grau de substitui??o e de polimeriza??o) influenciam diretamente no valor m?ximo da rela??o entre o precursor org?nico e inorg?nico para a forma??o das esferas h?bridas. As propriedades f?sico-qu?micas do material final (cristalinidade, porosidade, ?rea espec?fica e morfologia) mostraram uma depend?ncia direta com as propriedades do biopol?mero (grau de substitui??o e de polimeriza??o), indicando a versatilidade desta rota s?ntese. Os espectros de FTIR confirmaram a forma??o de um material h?brido quando se compara o espectro da CMC pura com os s?lidos obtidos ap?s a secagem. Os resultados de DRX mostraram um perfil de material amorfo para algumas amostras. Para alguns s?lidos foi poss?vel identificar a forma??o de uma fase cristalina relacionada com a alumina hidratada, ?xido de alum?nio e ?xido de cobre. As imagens obtidas por MEV indicaram a forma??o de um material com morfologia semelhante a uma esponja ap?s a calcina??o, caracter?stico de um s?lido altamente poroso. O perfil de adsor??o/dessor??o de N2 confirma a forma??o de materiais contendo micro-mesoporos com uma ?rea espec?fica entre 50-162 m2.g-1 para os suportes e 112-303 m2.g-1 para os catalisadores com cobre, indicando um aumento ?rea ap?s a adi??o do Cu por impregna??o devido a redissolu??o e recristaliza??o da fase alumina. Testes catal?ticos indicaram que os ?xidos s?o ativos e seletivos para a convers?o do glicerol (92-15%) a bioprodutos de alto maior valor agregado, confirmando a viabilidade do m?todo de s?ntese. / Catalytic supports based on aluminum oxide were synthesized by the method of hybrid spheres using carboxymethylcellulose (CMC) as organic precursor (template) and aluminum nitrate as inorganic precursor. The characterizations were performed by thermal chemical analysis (TGA), X-Ray diffraction (XRD), fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and N2 physisorption. The study of synthesis indicated that the characteristics of the biopolymer (degree of substitution and polymerization) directly influence on the maximum value of the ratio between the organic and inorganic precursor for the formation of hybrid spheres. The physicochemical properties of the final material (crystallinity, porosity, surface area and morphology) showed a direct dependence on the biopolymer properties (degree of substitution and polymerization), indicating the versatility of this synthesis route. The FTIR spectra confirm the formation of a hybrid material when comparing the pure CMC spectrum with the obtained solids after drying. The XRD results show a profile of amorphous and crystalline material for the different samples. For some solids were possible to identify the formation of a crystalline phase related to the hydrated alumina, aluminium oxide and copper oxide. The images obtained by SEM analysis showed the formation of a material with sponge-like morphology after calcination, characteristic of highly porous solid. The N2 adsorption/desorption isotherm profile confirms the formation of micro-mesoporous materials with a specific surface area between 50-162 m2.g-1 for the supports and 112-303 m2.g-1 for the copper-based catalysts, indicating an increase in the area after the addition of Cu by impregnation due to redissolution and recrystallization of alumina phase. Catalytic tests were tested in the glycerol conversion reaction (92-15%) to added value products in order to confirm their real viability.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-07-20T22:04:59Z No. of bitstreams: 1 MoacirBispoRamos_TESE.pdf: 16232608 bytes, checksum: 452eef16e8cb0bb6456bb9da73f46508 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-07-21T21:33:32Z (GMT) No. of bitstreams: 1 MoacirBispoRamos_TESE.pdf: 16232608 bytes, checksum: 452eef16e8cb0bb6456bb9da73f46508 (MD5) / Made available in DSpace on 2016-07-21T21:33:32Z (GMT). No. of bitstreams: 1 MoacirBispoRamos_TESE.pdf: 16232608 bytes, checksum: 452eef16e8cb0bb6456bb9da73f46508 (MD5) Previous issue date: 2015-12-07 / O presente trabalho prop?e a modifica??o do revestimento de eletrodos de baixo hidrog?nio, propiciando uma alternativa para execu??o de soldagem com o AWS E-7018 sem precisar resseca-los, reduzindo por conseguinte os custos financeiros e o tempo de fabrica??o de soldas estruturais de alta resist?ncia. As soldas deste estudo foram produzidas a partir de eletrodos com revestimento b?sico (higrosc?picos) - processo manual - pintados com tinta spray de alum?nio para altas temperaturas ou revestidos com filmes finos de PVC e de papel alum?nio (99,9%), comumente utilizados para prote??o de alimentos. A premissa b?sica ?, que estabelecendo uma barreira entre a atmosfera e o revestimento do eletrodo, poder-se-? diminuir os efeitos da alta higroscopicidade apresentada pelo revestimento, minimizando assim, a principal fonte de fornecimento de hidrog?nio ? po?a de fus?o durante a soldagem, tamb?m ? esperado, que a adi??o de novos materiais no revestimento ? po?a de fus?o, provoque altera??es metal?rgicas no metal depositado e consequentemente altera??es nas propriedades mec?nicas. Mensurar o hidrog?nio dissolvido no metal depositado ap?s soldado com os eletrodos modificados, avaliar a influencia dessas modifica??es nas microestruturas produzidas, nas propriedades mec?nicas da solda resultante e comparar esses resultados obtidos com procedimentos de soldagem padr?o normatizados e com os novos eletrodos imperme?veis recentemente desenvolvidos, balizou o estudo. Os resultados obtidos, na maioria das amostras soldadas com eletrodos modificados, apresentaram aumento significativo da resist?ncia mec?nica e de tenacidade, justificados pelo aumento percentual de ferrita acicular no metal depositado, sem, contudo, eleva??o significativa da dureza, quando comparados com a soldagem com eletrodo AWS E-7018 da forma tradicional. O hidrog?nio difus?vel nos eletrodos modificados manteve-se dentro do estabelecido pelos c?digos internacionais. / This paper suggests modifications in coating of electrodes providing an alternative for execution of welding with low hydrogen electrode AWS E7018 without having to dry it, reducing thus the cost and time of manufacturing of high resistance welds. The welds in this research were developed with basic coated electrodes (hygroscopic) ? SMAW process ? externally painted with aluminum spray paint for high temperatures or wrapped with thin plastic films (PVC) and aluminum foil films used commonly for food protection. The basic premise is that establishing a barrier between the atmosphere and the electrode coating could reduce the effects of high hygroscopicity presented by coatings of low hydrogen, minimizing this way the main source of supply of hydrogen to the fusion pool during welding. It is also expected that the addition of new materials from the electrode coating to the fusion pool would induce metallurgical changes in the deposited metal and, as a consequence, modifications in its mechanical properties. This research dealt with measuring the dissolved hydrogen in the deposited metal after welding with modified electrodes, evaluating the influence of these changes in the produced microstructures and in the mechanical properties of the resulting weld, and comparing the obtained results with the standard welding procedures and with the recently developed waterproof electrodes. The results obtained in most samples welded with modified electrodes showed increased mechanical resistance and increased tenacity due to the increased percentage of acicular ferrite in metal deposited without significant elevation of hardness, when compared with the traditional welding with AWS E7018 electrode and with ELBR?S BRH4R waterproof electrode. The diffusing hydrogen measured in the modified electrodes was kept inside the parameters defined by international codes.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2018-02-15T11:17:50Z No. of bitstreams: 1 CiceroLeonardoPereiraDeSouza_DISSERT.pdf: 12093980 bytes, checksum: 07b7fe22cb40d5bdd02b643fb06ab78a (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2018-02-16T11:10:32Z (GMT) No. of bitstreams: 1 CiceroLeonardoPereiraDeSouza_DISSERT.pdf: 12093980 bytes, checksum: 07b7fe22cb40d5bdd02b643fb06ab78a (MD5) / Made available in DSpace on 2018-02-16T11:10:32Z (GMT). No. of bitstreams: 1 CiceroLeonardoPereiraDeSouza_DISSERT.pdf: 12093980 bytes, checksum: 07b7fe22cb40d5bdd02b643fb06ab78a (MD5) Previous issue date: 2017-03-10 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / A soldagem a arco el?trico por eletrodo revestido (SMAW) ? uma das mais antigas t?cnicas de soldagem e a primeira a ser utilizada industrialmente em grande escala. Durante o s?culo XX a soldagem SMAW foi a mais usada como t?cnica de uni?o permanente de metais, sendo at? hoje, mesmo com coexist?ncia de diversas outras t?cnicas, uma das que possuem maior utiliza??o no mercado brasileiro. Nesse tipo de soldagem uma das maiores preocupa??es ? o cuidado no armazenamento do eletrodo, pois o mesmo n?o pode ficar exposto a atmosfera ambiente, j? que absorveria umidade, que ? danoso para a qualidade da solda. A umidade introduz na zona fundida o hidrog?nio que pode levar ao surgimento de trincas a frio. A solu??o normalmente usada ? a da ressecagem em temperaturas at? 450? C, acompanhada de armazenamento em estufas, pr?tica que gera custos adicionais para um projeto de fabrica??o. Nesse contexto o presente trabalho teve a inten??o de caracterizar a zona fundida de soldas feitas com eletrodos revestidos E7018 encobertos com filmes de alum?nio e PVC, aplicados com o intuito de resguarda-los contra a umidade ambiente, diminuindo custos e tempo com secagem, tamb?m variando o valor de aporte t?rmico utilizado durante a soldagem. Essa atual investiga??o d? continuidade ? pesquisa recente sobre a influ?ncia de tais filmes protetores na composi??o e, em especial, na microestrutura do metal de solda depositado, onde a quantifica??o dos constituintes e caracteriza??o microestrutural ocorreu atrav?s de um software para avalia??o de imagens. No presente caso, com a utiliza??o de um microsc?pio com emiss?o de campo, MEV-FEG, foram obtidas imagens com elevado contraste, que permitiram um levantamento detalhado dos tipos de constituintes presentes, assim como uma an?lise mais precisa de sua morfologia. Em particular foi poss?vel avaliar quantitativamente o efeito dos filmes protetores no tamanho de gr?o e na raz?o de aspecto do microconstituinte AF (ferrita acicular). Com base numa revis?o da literatura ? apresentada uma an?lise cr?tica acerca dos par?metros que tiveram maior relev?ncia na forma??o da microestrutura final e nas propriedades mec?nicas obtidas. Os resultados conduziram a constata??o de que para maiores valores de aporte t?rmico a microestrutura, em especial a ferrita acicular, tende a ser mais grosseira. Com a utiliza??o dos revestimentos de PVC e tinta de alum?nio obteve-se uma leve diminui??o nessa granulometria, j? que a microestrutura apresentou-se mais refinada do que com os eletrodos de refer?ncia (E7018 puro e BRH4R). / The shield metal arc welding (SMAW) is one of the oldest welding processes and the first one to be used in large industrial scale. During the XX century the SMAW was the most applied process for metal joining, remaining until nowadays as one of the most used in the Brazilian market. In this kind of welding one of the biggest problems is to avoid the hydrogen induced cold cracking, what imposes rigid requirements in the storing of the weld consumables. In order to avoid the humidity absorption, the consumables must be dried out in special ovens at temperatures in the order of 450 C, what implies in additional and higher manufacturing costs. In this context a recent research suggested modifications in coating of electrodes providing an alternative for execution of welding with low hydrogen electrode AWS E7018 without having to dry it, The welds were developed with basic coated electrodes (hygroscopic) externally painted with aluminum spray paint for high temperatures or wrapped with thin plastic films (PVC) and aluminum foil films. The induced metallurgical changes in the deposited metal, associated with the addition of new materials to the electrode coating, were investigated, wereby the microconstituents in the fusion zone were quantified using a software for image analysis. In the actual work, with the use of a field emission microscope, MEV-FEG, high contrast images could be obtained, this allowed a detailed characterization of the various microconstituents and a more precise description of their morphology. In special it was possible to evaluate the influence of the protective films in the grain size and aspect ratio of the microconstituent AF (acicular ferrite). On base of a literature review a critical analysis is presented, that embraces the effect of the more relevant parameters on the final microstructure and resulting mechanical properties. The results showed that for higher values of heat input the microstructure, especially the acicular ferrite, tends to be coarser. With the use of PVC coatings and aluminum paint, a slight reduction was achieved in this granulometry, since the microstructure was more refined than with reference electrodes (E7018 pure and BRH4R).

Made available in DSpace on 2015-12-04T11:45:28Z (GMT). No. of bitstreams: 1 Norberto_Giuntini.pdf: 3415741 bytes, checksum: 72c67797a89f14a5fc368022990ed41b (MD5) Previous issue date: 2003-06-03 / In 1990, Robert S. Kaplan and David P. Norton developed in United States of America, a new system as support for decision 1, denominated Balanced Scorecard. Even supposing it is not an innovation once it is based on knowledge and principles enclosed in theories previously developed, the Balanced Scorecard has organized some of these theoretical principles, having as objective a "Control Panel" construction to manager the Companies strategy by monitoring financial results, through performance operational indicators that influence these results, growing the analysis capability and organizational knowledge. The published books and articles about Balanced Scorecard2, simplify the methodology description for its implementation and relate some of success cases occurred in companies from United States of America. The Balanced Scorecard is coming to an experimental phase in order to verify its principles and concepts adherence. Many companies operating in Brazil are implanting and implementing it, without divulgating the facilities and difficulties to align the management practices to the strategy and budget, premise that constitute the differentiation for the system to support decision. With these circumstances, the objective for this work is to contribute with the scientific research, presenting the practical experience of one company in activity in the country, by the theoretical principles of Balanced Scorecard applied, divulgating the results obtained and if the company had to recover to improvisation and adaptation to fit the situation not contemplated in Kaplan and Norton methodology developed. The research was made by bibliographical study and empirical research, in order to transmit the concepts that fundaments the Balanced Scorecard utilization, such as not mystify the facility proclaimed from its authors, from a field research done in Alcoa. The research was done based in two questionnaires, and one was constituted of 70 "opened" questions, applied in the Quality Manager, responsible to implanting and implementing the Balanced Scorecard in the company. The second questionnaire was constituted by 21 questions, tabulated in a scale like Likert, with eight levels, and it was applied in managers and users departments of Balanced Scorecard. Even though the Balance Scorecard theory establish facilities for its omplntation and implementation, the work hypothesis was confirmed, the implementation to the referred system needs adjustments and adaptations. These adjustment and adaptations are related to the people initiaves who are in the different hierarchical level to decide and the operate the actions to strategy and acquire knowledge to innovate the way of making the tasks. Other important factor is the difficult to measure objectively the strategy, throughout indicators inter-relation that mean the relation for cause and effect for these actions and iniciatives. Despite of adjustments and adaptations presented all long way, the Balanced Scorecard, constitute a recent tool, presenting evolution level, by the experiences acquired in companies that are adopting it. Even though presents difficulties in its implementation, the Balanced Scorecard represent a system for support decision to create and develop strategy management, doing its theoretic and practical principles an approach so actual related to the necessities established by the best practices to be observed in the Global World and in the Manager Accountancy / No ano de 1990, Robert S. Kaplan e David P. Norton desenvolveram, nos Estados Unidos da Am??rica, um sistema de suporte ?? decis??o, denominado Balanced Scorecard. Muito embora n??o seja inovador, por utilizar conhecimentos e princ??pios contidos em teorias desenvolvidas anteriormente, o Balanced Scorecard organizou alguns desses princ??pios te??ricos, tendo como objetivo a constru????o de um "painel de controle" para gerenciar a estrat??gia da empresa, monitorando os resultados financeiros, atrav??s do desempenho de indicadores operacionais que influenciam esses resultados, aumentando a capacidade de an??lise e aprendizado organizacional. Os livros e artigos sobre o Balanced Scorecard publicados simplificam a descri????o metodol??gica de sua implementa????o e relatam somente os casos de sucesso ocorridos em empresas estabelecidas nos Estados Unidos da Am??rica. O Balanced Scorecard est?? passando por uma fase experimental para a verifica????o da ader??ncia dos seus princ??pios e conceitos. V??rias empresas operando no Brasil est??o implantando-o e implementando-o, n??o divulgando as facilidades e dificuldades para alinhar as pr??ticas gerenciais ?? estrat??gia e ao or??amento, premissas que constituem diferenciais do referido sistema de suporte ?? decis??o. Diante de tais circunst??ncias, este trabalho, tem como objetivo contribuir com a pesquisa cient??fica, apresentando uma experi??ncia pr??tica de uma empresa em atividade no pa??s, quanto ?? aplica????o dos princ??pios te??ricos do Balanced Scorecard, divulgando os resultados obtidos e se a empresa teve que recorrer a improvisa????es ou adapta????es para fazer frente a situa????es n??o contempladas na metodologia desenvolvida por Kaplan & Norton. A pesquisa foi efetuada por meio de estudo bibliogr??fico e pesquisa emp??rica, procurando transmitir os conceitos que fundamentam a utiliza????o do Balanced Scorecard, bem como desmistificar a facilidade apregoada por seus autores, a partir de pesquisa de campo efetuada na unidade Po??os de Caldas da Alcoa. A pesquisa foi efetuada utilizando-se de dois question??rios, o primeiro constitu??do de 70 perguntas "abertas", aplicado na Gerencia de Qualidade, respons??vel pela implanta????o e implementa????o do Balanced Scorecard na empresa. O segundo question??rio, constitu??do de 21 perguntas, tabuladas numa escala tipo Likert, com oito n??veis, foi aplicado nas ger??ncias e departamentos usu??rias do Balanced Scorecard. Embora a teoria do Balanced Scorecard estabele??a facilidades para a sua implanta????o e implementa????o, a hip??tese do trabalho foi confirmada, na medida que a implementa????o do referido sistema de suporte ?? decis??o necessita de ajustes e adapta????es. Estes ajustes e adapta????es est??o relacionados ?? cultura, cren??as e valores, administra????o dos recursos dispon??veis e das iniciativas das pessoas que atuam nos diferentes n??veis hier??rquicos para decidir e operacionalizar as a????es voltadas ?? estrat??gia e adquirir o conhecimento para inovar a forma de fazer as tarefas. Outro fator importante consiste na dificuldade de se mensurar objetivamente a estrat??gia, atrav??s da inter-rela????o de indicadores que traduzam numa rela????o de causa e efeito essas a????es e iniciativas. Apesar dos ajustes e adapta????es apresentadas ao longo do trabalho, o Balanced Scorecard, constitui-se numa ferramenta recente, apresentando est??gio de evolu????o, em fun????o das experi??ncias adquiridas pelas organiza????es que o est??o utilizando. Embora apresente dificuldades na sua implementa????o, o Balanced Scorecard representa um sistema de suporte ?? decis??o para criar e desenvolver a gest??o estrat??gica, fazendo dos seus princ??pios te??ricos e pr??ticos, uma abordagem bastante atual relacionada ??s necessidades estabelecidas pela melhores pr??ticas a serem observadas no mundo globalizado e pela contabilidade gerencial.

Made available in DSpace on 2014-12-17T15:01:54Z (GMT). No. of bitstreams: 1 KatiaRS_TESE.pdf: 3330352 bytes, checksum: a77bcf257b8b71b30d6dadf0de0d7fd4 (MD5) Previous issue date: 2012-03-30 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Among the waste generated in the petrochemical industry water associated with oil production is the most important. It is considered one of the great challenges due to the presence of considered toxic chemicals present in this composition. The presence of these substances difficult to reuse the water associated with the enhanced recovery processes, so that prior to their reuse or disposal, treatment is necessary. This paper aimed to study the removal efficiency of chemical species: Ba2+, Ni2+, Cd2+, Cu2+, Cr3+, Sr2+ and Zn2+, present in the composition of the water associated with oil production by electrocoagulation. The evaluation of removal of these chemical species was performed by laboratory tests using electrochemical batch reactors and continuous flow. Initial tests were performed with electrocoagulation of synthetic wastewater in batch reactor using iron electrode. Results of removal of Zn2+ and Ni2+ were 78 % and 59 % respectively. While the percentage of removed Ba2+ was 19 % by 30 minutes of treatment and by applying current of 1.10 A. The tests were performed on effluent batch reactor applying the electrochemical technique with stainless steel electrodes 304, the objective was to remove part of the dispersed oil and also of organic compounds in the effluent. Under the experimental conditions used, the maximum result was obtained TOG was 60 % and TOC was approximately 50 % compared to the initial concentration. In the experiments carried out in continuous reactor, with effluent semisynthetic, have been used electrodes of iron and aluminum and the results were 100 % removal of Cd2+, Cu2+, Cr3+ and Zn2+ and 77 % of Sr2+. These percentages were only attainable through the use of the iron electrode. However, when the electrode was replaced by aluminum, there was a reduction in the percentage of removal to 65 %, using the same flow rate and current. Therefore according to the results obtained using the iron electrode was more effective in removing these metals and the conditions of lower current and lower flow rate was satisfactory, as observed in the experimental design adopted / Dentre os res?duos gerados na ind?stria petroqu?mica a ?gua associada ? produ??o de petr?leo ? a mais importante. Ela ? considerada um dos grandes desafios devido ? presen?a de subst?ncias qu?micas consideradas t?xicas presente na sua composi??o. A presen?a dessas subst?ncias dificulta a reutiliza??o da ?gua associada nos processos de recupera??o avan?ada, fazendo com que antes da sua reutiliza??o ou descarte, seja necess?rio seu tratamento. Este trabalho teve como objetivo o estudo da efici?ncia de remo??o das esp?cies qu?micas: Ba2+, Ni2+, Cd2+, Cu2+, Cr3+, Sr2+e Zn2+, presentes na composi??o da ?gua associada ? produ??o de petr?leo por eletrocoagula??o. A avalia??o de remo??o dessas esp?cies qu?micas foi realizada por testes em laborat?rio utilizando reatores eletroqu?micos de batelada e de fluxo cont?nuo. Os testes iniciais da eletrocoagula??o foram realizados com efluente sint?tico em reator batelada utilizando eletrodo de ferro. Os resultados de remo??o de Zn2+ e de Ni2+ foram de 78% e 59%, respectivamente. Enquanto que o percentual removido de Ba2+ foi de 19%, em 30 minutos de tratamento, aplicando corrente de 1,10A. Os testes com efluente foram realizados em reator batelada aplicando a t?cnica eletroqu?mica com eletrodos de inox 304, o objetivo foi remover parte do ?leo disperso e tamb?m, de compostos org?nicos presentes no efluente. De acordo com as condi??es experimentais usadas, o resultado m?ximo obtido de TOG foi de 60% e de TOC foi aproximadamente de 50%, em rela??o ? concentra??o inicial. Para os experimentos realizados em reator cont?nuo, com efluente semi-sint?tico, foram usados eletrodos de ferro e de alum?nio e os resultados obtidos foram de 100% de remo??o de Cd2+, Cu2+, Cr3+ e Zn2+ e 77% de Sr2+. Esses percentuais s? foram poss?veis de alcan?ar mediante o uso do eletrodo de ferro. Entretanto quando esse eletrodo foi substitu?do pelo de alum?nio, ocorreu um decr?scimo no percentual de remo??o para 65%, utilizando-se a mesma vaz?o e corrente. Portanto segundo os resultados obtidos, a utiliza??o do eletrodo de ferro mostrou-se mais eficaz na remo??o desses metais e as condi??es de menor vaz?o e menor corrente foram satisfat?rias, conforme observado no planejamento fatorial adotado

Made available in DSpace on 2014-12-17T15:01:57Z (GMT). No. of bitstreams: 1 MarcianoHLN.pdf: 1368494 bytes, checksum: bb70e8ef85120a42eab9a63074c5ba8a (MD5) Previous issue date: 2005-11-25 / Gallium is an important material used in the electronic industry whose demand in the world market is increasing in view of its potential applications. A selective technique is required to allow for the production of the metal, separated from aluminium. Due to the fact that microemulsions constitute an attractive alternative to metal extraction procedures, microemulsified systems have been employed as gallium-selective extraction agents. Two surfactants have been synthesized: sodium 12-N,N-diethylamino-9,10-dihydroxyestearate (AMINE) and saponified coconut oil (SCO), both produced from raw materials readily available in Northeastern Brazil. Also, the commercial extraction agent KELEX-100, conventionally used with the same purpose, has been used in this work for comparison. The optimization of the extraction process with microemulsions was carried out by investigating the influence of some parameters, namely the type of cosurfactant, the cosurfactant/surfactant (C/S) ratio, the pH and concentration of metals in the aqueous phase. Pseudoternary diagrams, which are representative of the microemulsified systems under study, have been constructed in order to establish the boundaries of the regions where the several Winsor systems are formed. An experimental planning methodology (Scheff? Net) has been used to optimize the extraction. The extraction percentage values were as high as 100% for gallium and 99.99% for aluminium for the system with KELEX-100; 96.6% for gallium and 98.8% for aluminium for the system containing AMINE; and 88% for gallium and 85% for aluminium for the system with SCO. The microemulsified system chosen for presenting the best results in gallium extraction was composed by SCO/isoamyl alcohol/kerosene/Bayer licquor with a C/S ratio of 28 and pH of the original aqueous phase of 6.0. The selectivity that has not been observed in the extraction stage was accomplished in the reextraction process using HCl. For the KELEX-100 system, gallium was reextracted at 100% with 6M HCl and aluminium was reextracted at 100% with 0.8M HCl. For the AMINE system, the reextraction percentages were also 100% for both metals, using 6M HCl for gallium and 0.5M HCl for aluminium. On the other hand, the reextraction percentages for the system with SCO were as high as 84% for gallium and 92% for aluminium, with HCl in the same concentrations as those used in the AMINE system. Finally, an optimized system was applied in the gallium extraction process employing a reciprocating perforated-plates extractor. As a result, the metal content was extracted at a recovery rate of 95% for gallium and 97% for aluminium / O g?lio ? um importante material utilizado na ind?stria eletr?nica, cuja demanda no mercado mundial est? crescendo em raz?o de suas aplica??es. A obten??o do metal necessita de um m?todo seletivo para separ?-lo do alum?nio. Sendo as microemuls?es uma alternativa atrativa para a extra??o de metais, decidiu-se utilizar sistemas microemulsionados como extratantes seletivos ao g?lio. Dois tensoativos foram sintetizados; o 12-N,Ndietil-amino-9,10-dihidroxiestearato de s?dio (AMINADO) e o ?leo de coco saponificado (OCS), obtidos de mat?rias-prima dispon?veis na regi?o Nordeste do Brasil. O extratante comercial KELEX-100, convencionalmente utilizado com essa mesma finalidade, foi usado neste trabalho para compara??o. A otimiza??o do processo de extra??o por microemuls?es foi realizada atrav?s do estudo da influ?ncia de par?metros, tais como: tipo de cotensoativo, raz?o C/T, pH e concentra??o de metais na fase aquosa. Os diagramas pseudotern?rios, representativos dos sistemas microemulsionados em estudo, foram estabelecidos no sentido de delimitar as regi?es de exist?ncia dos sistemas de Winsor. Uma metodologia de planejamento experimental (Rede Scheff?) foi usada para otimizar a extra??o. O percentual de extra??o atingiu valores de at? 100 % para o g?lio e 99,99% para o alum?nio para o sistema com o KELEX-100; 96,6 % para o g?lio e 98,8 % para o alum?nio no sistema contendo AMINADO; 88 % para o g?lio e 85 % para o alum?nio no sistema com OCS. O sistema microemulsionado selecionado por apresentar os melhores resultados na extra??o do g?lio foi composto de: OCS/?lcool isoam?lico/querosene/licor de Bayer a uma raz?o C/T igual a 28 e pH da fase aquosa igual a 6. A seletividade que faltou ? extra??o foi atingida na etapa de reextra??o utilizando-se solu??es de HCl. Para o sistema com o KELEX-100, reextraiu-se g?lio a 100% com HCl 6M e alum?nio a 100% com HCl 0,8M. No caso do sistema com AMINADO, os percentuais de reextra??o de ambos os metais tamb?m foram de 100%, usando-se HCl 6M para g?lio e HCl 0,5 M para o alum?nio. Por outro lado, para o sistema com OCS, os percentuais de reextra??o foram tais que 84% do g?lio e 92% do alum?nio foram recuperados com HCl nas mesmas concentra??es empregadas no caso do AMINADO. Um sistema otimizado foi, finalmente, aplicado na extra??o do g?lio em um extrator de pratos perfurados rec?procos (EPPR) e permitiu a extra??o deste metal com uma taxa de recupera??o de g?lio a 95% e alum?nio a 97%

Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2017-06-20T16:10:30Z No. of bitstreams: 1 2010 - Cristiane Alves Foga?a.pdf: 2979226 bytes, checksum: 16723accb45fe9477013bff730b4755d (MD5) / Made available in DSpace on 2017-06-20T16:10:30Z (GMT). No. of bitstreams: 1 2010 - Cristiane Alves Foga?a.pdf: 2979226 bytes, checksum: 16723accb45fe9477013bff730b4755d (MD5) Previous issue date: 2010-03-04 / Funda??o Carlos Chagas Filho de Amparo ? Pesquisa do Estado do RJ, FAPERJ, Brasil. / The present study aimed to evaluate some limiting factors to the growth of Toona ciliata M. Roem. var. australis (Australian red cedar). In chapter I, it was evaluated the growth of Toona ciliata seedlings inoculated with arbuscular mycorrhizae fungi (FMAs), Acaulospora laevis, A. morrowiae, Entrophospora colombiana, E. contigua, Gigaspora margarita, Glomus clarum, Scutellospora calospora, S. gilmorei, S. heterogama e S. pellucida. In chapter II, it was evaluated the contents and accumulations of nutrients in Australian red cedar seedlings, submitted the complete solution, diluted solution 1/2 and 1/4. In chapter III, it was verified the symptoms of macronutrients deficiency, nutrients contents and accumulations in the Australian red cedar plants submitted the complete solution with omission of N, P, K, Ca and Mg. Chapter IV, it was observed the reply of the species the aluminum presence, using treatments with complete solution diluted the 1/4 with addition of 0, 5 and 20 mg. L-1 de Al. Between AMF tested, A. morrowiae, E. contigua e S. pellucida were most efficient in promoting the accumulation of dry weight of aerial part, development of the area leaf and phosphorous content on leaf in Toona ciliata seedlings, beyond presenting the biggest densities of esporos.50 cm-3 of substrate. And the biggest incidence of mycorrhizae settling in Toona ciliata seedlings was gotten with the species S. pellucida. The behavior of the species in reply to the use of nutritional solutions complete and diluted 1/2 and 1/4, showed that the biggest increment in height, diameter and dry weight had occurred in plants submitted at diluted solution the 1/4. The macronutrients contents and accumulations in Australian red cedar plants presented the following decreasing order: N > K > Ca > P > Mg. With regard to nutritional deficiency it verified that the omission of K was the one that more affected the development of the plant in height. The limitation in the increment stem diameter of the plants occurred in all the treatments, with exception of the complete solution. The production of total weight dry of the plants was affected in all the treatments with omission of nutrients, in according the following decreasing order: Complete Solution > - P > - Mg > - N > - K > - Ca. The initial growth of Toona ciliata seedlings was affected by the omission of all the macronutrients, having been the similar symptoms with the symptoms of other species of the same family. The immediate damages most intense and had been observed in the omission of K and Ca. Thus, the Toona ciliata species demonstrated to be demanding in macronutrients in the following decreasing order: K > N > Mg > Ca > P. The reply of the species the aluminum presence demonstrated that the growth, nutrient content and accumulation in Australian red cedar plants were stimulated in the presence of 5mg.L-1 of aluminum. The addition of 20 mg.L-1 de Al reduced the growth of the plants and macronutrients accumulation, in the following decreasing order: Ca > Mg > N > P > K. The visual symptoms of fitotoxicity had been typical to this element, beyound of the leaf with intense green coloration progressing for the yellow; the leaves oldest had progressed for yellow-brown, the edges to the limb center; and curving of new leaves. / O presente trabalho teve como objetivo avaliar alguns fatores limitantes ao crescimento de Toona ciliata M. Roem. var. australis (cedro-australiano). No cap?tulo I, avaliou-se o crescimento de mudas de cedro-australiano inoculadas com fungos micorr?zicos arbusculares (FMAs), Acaulospora laevis, A. morrowiae, Entrophospora colombiana, E. contigua, Gigaspora margarita, Glomus clarum, Scutellospora calospora, S. gilmorei, S. heterogama e S. pellucida. No cap?tulo II, foram avaliados os teores e ac?mulos de nutrientes em mudas de cedro-australiano, submetidas ? solu??o nutritiva de Hoagland & Arnon modificada, completa, dilu?da a 1/2 e a 1/4 de for?a i?nica. No cap?tulo III, verificou-se os sintomas de defici?ncia de macronutrientes, teores e ac?mulos de nutrientes nas plantas de cedroaustraliano crescidas em solu??o nutritiva com omiss?o de N, P, K, Ca e Mg. No Cap?tulo IV, observou-se a resposta da esp?cie estudada na presen?a de alum?nio, empregando tratamentos com solu??o nutritiva dilu?da a 1/4 com adi??o de 5 e 20 mg.L-1 de Al, al?m de uma testemunha Entre os fungos micorr?zicos arbusculares testados, A. morrowiae, E. contigua e S. pellucida foram os mais eficientes em promover o ac?mulo de mat?ria seca da parte a?rea, desenvolvimento da ?rea foliar e teor de f?sforo foliar em mudas de Toona ciliata, al?m de apresentarem as maiores densidades de esporos por 50 cm3 de substrato. A maior coloniza??o micorr?zica em mudas de Toona ciliata foi obtida com a esp?cie f?ngica S. pellucida. O comportamento da esp?cie em resposta ao emprego de solu??es nutritivas completas, dilu?da a 1/2 e 1/4, mostrou que o maior incremento em altura, di?metro e mat?ria seca ocorreram em plantas submetidas ? solu??o dilu?da a 1/4. Os teores e ac?mulos de macronutrientes em plantas de cedro-australiano seguiram a seguinte ordem decrescente: N > K > Ca > P > Mg. Com rela??o ? defici?ncia nutricional, verificou-se que a omiss?o de K foi a que mais afetou o crescimento em altura. A limita??o no crescimento em di?metro do coleto das plantas ocorreu em todos os tratamentos, com exce??o da solu??o de Hoagland & Arnon. A produ??o de massa seca total das plantas foi afetada em todos os tratamentos com omiss?o de nutrientes, obedecendo ? seguinte ordem decrescente: Completo> -P > -Mg > -N > -K > -Ca. O crescimento inicial de mudas de Toona ciliata ? afetado pela omiss?o de todos os macronutrientes, sendo os sintomas semelhantes com os sintomas de outras esp?cies da mesma fam?lia. Os danos mais intensos e imediatos foram observados na omiss?o de K e Ca. Assim, a esp?cie Toona ciliata demonstrou ser exigente em macronutrientes na seguinte ordem decrescente: K > N > Mg > Ca > P. A resposta da esp?cie ? presen?a de alum?nio demonstrou que o crescimento, teor e ac?mulo de nutrientes em plantas de cedro-australiano foram estimulados na presen?a de 5mg.L-1 de alum?nio. A adi??o de 20 mg.L-1 de Al reduziu o crescimento das plantas e o ac?mulo de macronutrientes, na seguinte ordem decrescente: Ca > Mg > N > P > K. Os sintomas visuais de fitotoxidez associados ? dose de 20 mg.L-1 de Al foram t?picos da toxidez a este elemento, al?m das folhas apresentarem colora??o verde intensa progredindo para o amarelecimento; com a acentua??o dos sintomas, as folhas mais velhas progrediram para amarelo-castanho, dos bordos para o centro do limbo e enrolamento ou encurvamento de folhas novas.

Made available in DSpace on 2014-12-17T15:01:47Z (GMT). No. of bitstreams: 1 PatriciaGSL.pdf: 4325839 bytes, checksum: ed5182708cd9548f2c8eca5937447cd6 (MD5) Previous issue date: 2008-12-22 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / This work aims to investigate the process of Dissolved air Flotation (DAF) for clarifying water samples with low turbidity using aluminum sulphate and Moringa oleifera seeds as coagulants. The experimental procedure was carried out in a bench scale flotation unit. The influences on the pre-treatment conditions (coagulant dosage and flocculation time) and flotation parameters (superficial application rate and recirculation rate) were evaluated considering the efficiency of the process. The efficiency was evaluated by determining the turbidity of the untreated and treated water samples. The results obtained showed that turbidity reduction can be obtained very efficiently by using DAF and the latter coagulant in low turbidity water. Using aluminum sulphate in pH?s 5.0 and 6.0 better efficiencies were obtained with low concentrations (15 mg/L), achieving values of 92% of turbidity reduction. In the case of use of Moringa oleifera better efficiencies of reduction of turbidity were reported when using a concentration of 50 mg/L in all range of pH?s, achieving 86% of reduction. The zeta potential was also determined, in an attempt to aid comprehension of the coagulation mechanisms involved. The coagulation mechanisms with Moringa oleifera seeds were shown to be adsorption and charge neutralization, as well as adsorption and bridging. Concerning aluminum sulphate, the predominant mechanisms are adsorption and charge neutralization and enmeshment in a precipitate. The results indicate that for low turbidity water, Moringa oleifera seeds could potentially be a viable substitute for aluminum sulphate / O presente trabalho tem como objetivo investigar o processo da flota??o por ar dissolvido sob press?o - FAD para clarifica??o de ?guas com baixa turbidez utilizando sulfato de alum?nio e sementes de Moringa oleifera como coagulantes. O procedimento experimental foi realizado em uma unidade de flota??o em escala de bancada. Foram avaliadas as influ?ncias das condi??es do pr?-tratamento (dosagem de coagulante e tempo de flocula??o) e par?metros de processo da flota??o (taxa de aplica??o superficial e taxa de recircula??o) na efici?ncia do processo. A efici?ncia foi avaliada pela determina??o de turbidez nas amostras de ?gua bruta e tratada. Os resultados obtidos mostraram que elevadas efici?ncias de redu??o da turbidez podem ser conseguidas com o uso da FAD em ?guas com baixa turbidez utilizando estes coagulantes. Para o sulfato de alum?nio, nos pHs 5,0 e 6,0 as melhores efici?ncias foram alcan?adas com baixas dosagens (15 mg/L), alcan?ando valores de at? 92% de redu??o. Para a Moringa oleifera, as melhores efici?ncias de redu??o de turbidez foram ? dosagem aproximada de 50 mg/L para todos os pHs, alcan?ando valores de 86% de redu??o. Determinou-se tamb?m o potencial zeta, com o objetivo de auxiliar na compreens?o dos mecanismos envolvidos na coagula??o. Os mecanismos de coagula??o com sementes de Moringa oleifera indicam ser adsor??o e neutraliza??o de cargas e adsor??o e forma??o de pontes. No que diz respeito ao sulfato de alum?nio os mecanismos predominantes s?o adsor??o e neutraliza??o de cargas e varredura. Os resultados indicam que para ?guas de baixa turbidez, as sementes de Moringa oleifera podem ser um substituto potencialmente vi?vel em rela??o ao sulfato de alum?nio