Submitted by Lucienne Costa (lucienneferreira@ufcg.edu.br) on 2018-04-12T20:30:01Z No. of bitstreams: 1 PAULO GERMANO TAVARES MARINHO FILHO – DISSERTAÇÃO (PPGECA) 2017.pdf: 8052393 bytes, checksum: 1aa31fc493264a0804e2c04a30e23151 (MD5) / Made available in DSpace on 2018-04-12T20:30:01Z (GMT). No. of bitstreams: 1 PAULO GERMANO TAVARES MARINHO FILHO – DISSERTAÇÃO (PPGECA) 2017.pdf: 8052393 bytes, checksum: 1aa31fc493264a0804e2c04a30e23151 (MD5) Previous issue date: 2017-06-06 / Atualmente tem-se desenvolvido pesquisas voltadas para melhoria do desempenho das misturas asfálticas a fim que estes sejam duráveis, que apresentem menores deformações permanentes e tenham uma maior vida de fadiga. Para isto, tem-se utilizado técnicas de modificação de ligantes asfálticos, e.g. polímeros, fíleres, fibras e recentemente os nanomateriais, quem têm apresentado viabilidade técnica e econômica para este fim. Esta pesquisa tem por objetivo estudar a incorporação de nanopartículas de dióxido de titânio na modificação de ligantes asfálticos tipo CAP 50/70 e ligante 55/75-E. As nanopartículas foram adicionadas nos teores de 0%, 3%, 4% e 5%, no estado pura e modificada superficialmente pelo uso de três agentes distintos (ácido oleico, álcool benzílico e oleilamina). A pesquisa foi dividida em quatro etapas: a primeira etapa consistiu na análise da Espectroscopia de infravermelho por transformada de Fourier (FTIR) destes ligantes, na segunda etapa foi realizada a avaliação destes por meio de ensaios físicos (penetração e ponto de amolecimento) e reológicos [viscosidade rotacional, grau de desempenho (PG), fluência e recuperação sob tensões múltiplas (MSCR) e varredura linear de amplitude (LAS)], na terceira etapa os ligantes foram submetidos à exposição de radiação UV natural e variações térmicas durante o período de 3 meses e analisados por meio de FTIR e ensaios reológicos e a última etapa consistiu na modificação superficial das nanopartículas a fim de melhorar a dispersão do material na matriz asfáltica. Os resultados indicaram a viabilidade técnica da incorporação das nanopartículas de TiO2 ao ligante tipo CAP 50/70, pois aumentaram a vida de fadiga, a resistência a deformações e retardaram o processo de envelhecimento, além disto, a modificação superficial das nanopartículas com oleilamina melhorou a interação da partícula com o ligante, contribuindo para melhoria dos parâmetros supracitados. A incorporação do nanoTiO2 aos ligantes do tipo 55/75-E não forneceu melhorias significativas quanto ao observado para o CAP 50/70, embora tenha apresentado resultados superiores ao ligante de referência (55/75-E puro). A incorporação de nanopartículas modificadas superficialmente com oleilamina ao ligante 55/75-E proporcionou maior resistência ao envelhecimento e menor suscetibilidade a deformações permanentes e trincas, no entanto, estes ganhos foram mais expressivos para o CAP 50/70. / Researches have been carried out on improving the performance of asphalt binders so they can be durable, present less permanent deformation and longer fatigue life. For this, asphalt binder modification techniques have been used, e.g. polymers, fillers, fibers and, more recently, nanomaterials, which have presented technical and economic feasibility. This research aims to study the incorporation of titanium dioxide nanoparticles in the modification of asphalt binders CAP 50/70 and 55/75-E. The nanoparticles were added to the base asphalt binder at concentrations of 3, 4 and 5% of weight, in both pure and surface modified states. Three different agents were used for the surface modification: oleic acid, benzyl alcohol and oleylamine. The research was divided into four stages: the first one consisted in the analysis of the Fourier transform infrared spectroscopy (FTIR) of these binders, in the second one the binders were evaluated by means of physical (penetration and softening point) and rheological [rotational viscosity, performance grade (PG), multiple stress creep recovery (MSCR) and linear amplitude sweep (LAS)] tests, in the third stage the binders were exposed to natural UV radiation and thermal variations during a period of 3 months and analyzed by means of FTIR and rheological tests, and the last stage consisted in the surface modification of the nanoparticles. The results indicated the technical feasibility of the incorporation of TiO2 nanoparticles to the binder CAP 50/70, since it increased fatigue life, resistance to deformations and delayed the aging process. In addition, the surface modification of the nanoparticles with oleylamine improved the interaction of the particles with the binder, contributing to the improvement of the parameters mentioned above. The incorporation of nanoTiO2 to the 55/75-E binder did not provide as significant results as the observed for CAP 50/70, although it presented better results than the base binder. The incorporation of surface modified nanoparticles with oleylamine to the 55/75-E binder provided higher resistance to aging and less susceptibility to permanent deformations and cracks, although less expressive than the verified for CAP 50/70.

Orientador: Javier Telis Romero / Banca: José Francisco Lopes Filho / Banca: Ana Lúcia Gabas / Resumo: Neste trabalho estudou-se a influência da temperatura (275,4 a 359,8 K) e teor de gordura (10,2% a 30,6%) nos parâmetros reológicos do creme de leite, como também a influência da temperatura (278 a 343 K) nos parâmetros reológicos do leite condensado. A caracterização reológica foi realizada com o auxílio de um reômetro rotacional do tipo cone e placa, localizado no DEA/FZEA/USP, e de um reômetro rotacional do tipo cone e placa, localizado no DETA/UNESP. Os dados experimentais foram ajustados aos modelos de Ostwald-De Waele, Bingham e Herschel-Bulkley, para determinação dos parâmetros reológicos. Observou-se para o leite condensado, em toda faixa de temperatura de estudo (278 a 343 K), comportamento pseudoplástico, sem tensão inicial de escoamento, e neste caso os parâmetros reológicos foram ajustados de acordo com o modelo de Otswald-De-Waele. Para o creme de leite, observou-se comportamento viscoplástico (Binghamiano), na faixa de temperatura entre 275,4 e 306,4 K nas concentrações de 20,3 a 30,6%, sendo, neste caso, os parâmetros reológicos ajustados de acordo com o modelo de Bingham. Para a faixa de temperatura entre 275,4 e 359,8 K nas concentrações de 10,2 a 20,3%, observou-se comportamento Newtoniano, sendo, neste caso, os parâmetros reológicos ajustados de acordo com o modelo de Newton. Além disso, para temperaturas acima de 313K, em todas as concentrações, foi observado comportamento Newtoniano. Para os dois produtos, a influência da temperatura foi representada por uma função exponencial. Correlações simples foram utilizadas para analisar o efeito combinado da temperatura e da fração de gordura nos parâmetros reológicos do creme de leite. / Abstract: The rheological behavior of milk cream with different fat contents (10,2% to 30,6%) was studied at a wide range of temperatures (275,4 to 359,8 K), as also the rheological behavior of sweetened condensed milk at a wide range of temperatures (278 to 343K). The rheological characterization was made using a cone and plate rotational rheometer, located at DEA/FZEA/USP, and a rheometer of the type cone and plate, located in DETA/UNESP. The experimental data have been adjusted to the Ostwald-De Waele, Bingham and Herschel-Bulkley models, to determine the rheological parameters. It was observed for sweetened condensed milk, in all the temperature bands, pseudoplastic behavior, without yield stress, and the rheological parameters have been adjusted the Otswald-De-Waele model. For milk cream, it was observed viscoplastic behavior (Binghamian), in the temperature bands between 275,4 and 306,4 K at fat contents of 20,3% to 30,6%. The rheological parameters have been adjusted to the Bingham model. For the temperature bands between 275,4 and 359,8 K at fat contents of 10,2% to 20,3%, it was observed Newtonian behavior, and therefore the rheological parameters have been adjusted to the Newton model. Besides, for temperatures above 313K, in all concentrations, it was observed Newtonian behavior. For the two products, the influence of the temperature was represented by an exponential function. Simple correlations were used to analyze the effect of the temperature and the fat fraction in the rheological parameters of the milk cream. / Mestre

Resumo: Rhizobium tropici e outras bactérias pertencentes à ordem Rhizobiales são produtores de polissacarídeos extracelulares (EPS), que possuem a função de molécula receptora do micro simbionte, fazendo uma interação célula/célula e desencadeando o processo de nodulação. A diversidade de estruturas e composição química apresentadas pelas moléculas de EPS é refletida pela diversidade de enzimas responsáveis pela sua síntese. Neste trabalho, buscou-se a inativação através da mutagênese insercional por transposição in vitro dos genes exoZ da estirpe selvagem Rhizobium tropici SEMIA 4080 envolvidas na síntese das subunidades repetitivas do EPS e no tanden phbAB, responsáveis pela síntese do PHB, com o intuito de obter microrganismos com aspecto altamente mucoso, produtor superior de EPS em relação a estirpe selvagem. Os mutantes obtidos apresentaram colônias mucosas quando cultivados nos meios de culturas PSYA, demonstrando que estirpes de rizóbio mutantes nos genes exoZ e phbAB são capazes de formar biofilme "in vitro" e, ao avaliar a eficiência relativa na produção de EPS, o mutante 4080 Z03 apresentou o melhor resultado. Para as três amostras de EPS foi possível observar um comportamento de fluxo de líquidos pseudoplástico e, também, a influência da concentração de EPS sobre a viscosidade aparente das soluções aquosas. A estirpe selvagem e todos os mutantes induziram a formação de nódulos em feijoeiro (fenótipo Fix+), sugerindo que os genes exoZ e phbAB não estão envolvidos nos processos de infecção e formação nodular mas, sendo necessários para a fixação biológica de nitrogênio / Abstract: Rhizobium tropici and other bacteria belonging to the order Rhizobiales are extracellular polysaccharides (EPS) producers, which possess the function of the receptor molecule to function as micro-symbiont, making an interaction cell / cell and triggering the nodulation process. The diversity of structures and chemical composition of EPS presented by molecules is reflected by the diversity of enzymes responsible for its synthesis. In this study, we sought to inactivation by insertional mutagenesis by "in vitro" transposition of genes from wild type exoZ Rhizobium tropici SEMIA 4080 involved in the synthesis of the EPS repeating subunits and phbAB tanden, responsible for synthesis of PHB, in order to obtain microrganisms with high mucosal aspect producer of EPS compared to wild type. The mutants showed mucous colonies when grown in culture media PsyA, demonstrating that mutant strains in genes exoZ and phbAB from rhizobia are able to form biofilm "in vitro", and to evaluate the relative efficiency in the production of EPS, the mutant 4080 Z03 showed the best result. For the three samples of EPS was possible to observe a flow behavior of pseudoplastic fluids, and also the influence of EPS concentration on the apparent viscosity of aqueous solutions. The wild type and mutants induced the formation of nodules in common bean (Fix+ phenotype), suggesting that genes exoZ and phbAB are not involved in the processes of infection and nodule formation, but are necessary for nitrogen fixation / Orientador: Eliana Gertrudes de Macedo Lemos / Coorientador: Manoel Victor Franco Lemos / Banca: Regiane de Fátima Travensolo Sacomano / Banca: Simone Cristina Picchi / Banca: Jackson Antônio Marcondes de Souza / Banca: Eliamar Aparecida Nascimbem Pedrinho / Doutor

Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology. / Pulsed Ultrasound Velocimetry combined with Pressure Difference (PUV+PD) measurement is a non-invasive in-line rheometric technique which is used to analyse the complex flow properties of industrial fluids for quality control purposes. Cape Peninsula University of Technology (CPUT) and Technical Research Institute of Sweden (SP) have developed and patented a new PUV+PD based system, called Flow-Viz™. Despite this advancement, the system and ultrasound sensor technology have not been fully tested and evaluated in a wide range of industrial fluids. Acoustic characterisation tests were carried out at SP, with the aim of understanding the ultrasound beam properties after propagating through industrial stainless steel (316L) pipe walls. For these tests, a high-precision robotic XYZ-scanner and needle hydrophone setup were used. Different ultrasound sensor configurations were mounted to a stainless steel pipe while using different coupling media between the transducer-to-wedge and sensor wedge-to-pipe boundaries. The ultrasound beam propagation after the wall interface was measured by navigating the needle hydrophone within a predefined 2-dimensional spatial grid. The most suitable coupling material was determined from the acoustic characterisation, and then used in the in-line rheological characterisation tests to evaluate the performance of the Flow-VizTM rheometric unit against conventional tube viscometry. The in-line rheological tests were conducted with bentonite, kaolin and Carboxymethyl cellulose (CMC) model fluids. The flow loop used consisted of three different pipe test sections; and two concentrations of each fluid were tested in order to ascertain the consistency of the measurements. The in-line rheological tests showed good agreement (±15%) between the two techniques and Flow-VizTM was able to provide important data at very low shear rates. Acoustic characterisation indicated that variations in the beam properties were highly dependent on the acoustic couplants used to mount the sensors to the stainless steel pipes. Furthermore, the in-line results showed the effectiveness of Flow-VizTM as an industrial rheometer. The non-invasive ultrasound sensor technology, was for the first time acoustically characterised through stainless steel. This information will now be used to further optimise the unique technology for advanced industrial applications, e.g. oil drilling fields, complex cement grout and food processing applications.

Thesis (MTech (Biomedical Technology))--Cape Peninsula University of Technology, 2016. / Biochemical and haematological changes occur in red blood cellular products during the recommended storage period of 35 to 42 days at 1°C to 6°C. The restriction of the sodium/potassium pump at specified temperatures result in low intracellular potassium ion levels while an increase in sodium ion levels are observed and acidosis occurs as a result of low pH concentrations due to glucose consumption. Structural and morphological changes occur such as the release of free haemoglobin, lactate dehydrogenase and potassium into the supernatant causing the formation of spheroechinocytes and osmotic fragility. All these factors negatively impact the rheological properties of blood. These changes that transpire in the red cells during the storage period are referred to as “storage lesions”. Transfusion-associated graft versus host disease is an immunological and often fatal adverse transfusion reaction with gamma irradiation of cellular blood products used as a preventative measure. Gamma irradiation exacerbates storage lesions and of particular concern has been the increased potassium levels resulting in neonatal and infant hyperkalaemia. The storage lesions occurring in non-irradiated red blood cellular products are well documented although the literature regarding its irradiated counterparts has been less studied. A study of this nature has not previously been done in Cape Town, South Africa.

Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2016. / Polymers used as flocculants in the secondary sludge dewatering process are one of the most expensive inputs in these plants. The disadvantage is that these polymers cannot be recycled. Currently, controlling of polymer dosing rate is done by trial and error method. It has been shown that huge savings can be made by optimising the polymer dosing using rheological properties. It is not an easy task to optimise this process because of changing sludge characteristics on a daily, seasonal and annual basis. To try and optimise polymer dosing and polymer concentration, the variation in rheological properties needs to be understood first. The correlation between the process parameters and the rheological properties needs to be determined. There is currently no database of rheological properties of secondary wastewater sludge feeding belt filter presses available. To address these issues, a 12 week assessment of the rheological properties of the sludge feed to the belt filter press before and after conditioning in four wastewater treatment plants in Cape Town was conducted. The rheological properties were determined using an MCR-51 rheometer with parallel plate geometry under controlled temperature. After concluding the assessment, a 3-level Box-Behnken factorial trial was conducted at Plant K wastewater treatment plant to statistically analyse the correlation and/or interactions between the process parameters (sludge feed flow rate, polymer dosing concentration, polymer dosing rate and belt press speed) and the rheological properties of the sludge to optimise the plant performance.

Thesis (MTech (Civil Engineering))--Cape Peninsula University of Technology, 2016. / The addition of certain fillers and additives in conventional concrete is imperative for improving its rheological properties. The effect of additives, namely limestone (LS) and superplasticisers (SP), on the hydration kinetics of self-compacting concrete (SCC) was investigated on cement paste scale. These additives interact mostly with cement paste, since aggregates are considered to be inert materials. An understanding of the effect of these additives on the hydration kinetics of cement paste is paramount to the design of an SCC with excellent properties. Four CEM I 52.5N Portland cements from one supplier but produced at different factories, LS and two types of SP, were used in this research. The hydration kinetics were evaluated by monitoring the elastic modulus growth of the cement pastes. Different coefficients of the self-acceleration kinetics equation – the self-acceleration constant, characteristic time and real time of hydration – were used to establish the effect of different concentrations of SP with and without the optimum concentration of limestone (30%) on the hydration kinetics of cement pastes. As far as can be ascertained, this is the first time the rheokinetic model has been used to describe the initial hydration of SCC paste.

No description available.

Orientador: Peter Christian Hackspacher / Banca: Fernando Flecha Alckmim / Banca: Marcos Egydio Silva / Banca: Ticiano Saraiva / Banca: Hans Dirk Hebert / Resumo: A grande variedade de microestruturas e texturas encontradas nos minérios de ferro do Quadrilátero Ferrífero no Brasil gera uma ampla diversidade de propriedades físicas com grandes implicações para o seu beneficiamento. O vínculo entre reologia, mecanismos de deformação que atuaram na formação de várias microestruturas e texturas ou orientações cristalográficas preferenciais (OCP), fornecem resultados que podem ser aplicados para uma explotação estratégica dos diferentes tipos de minérios, implicando na melhoria de áreas alvos. Este estudo foi focado na avaliação da correlação de microestruturas/texturas com parâmetros de flotação, visando otimizar o processo de flotação para aumentar a recuperação dos minérios "pobres" (ricos em sílica), que comumente contêm menos de 64% de Fe. Uma série de técnicas, incluindo difração por nêutrons, raios-X e elétrons retroespalhados (elétron backscattering difraction), bem como análises granulométricas e de imagens dos concentrados de flotação foram aplicados neste trabalho. Os resultados obtidos por meio das análises microestruturais e texturais, permitiram enquadrar os diferentes minérios no seu contexto tectônico, dentro do Quadrilátero Ferrífero. Adicionalmente, a diversidade reológica, obtida por várias técnicas resultou na definição de parâmetros de correlação com a flotação, que podem ser aplicados na indústria de beneficiamento, contribuindo para aumentar a recuperação do minério de ferro. / Abstract: The wide range of minerals, microstructures and textures encountered in iron ores of the Quadrilátero Ferrífero region in Brazil, generates a diversity of physical properties with implications to its processing. The linking between rheology and deformation mechanisms which acted in microstructure and texture or crystallographic preferred orientations (CPO), formation provide results witch can be applied in strategic exploitation of different ore types, leading to the improvement of the selected targets. This study was focused in the evaluation and correlation of textures, microstructures with flotation parameters, aiming to optimize the flotation processing to increase the recovery of low-grade iron ores, which commonly contain less than 64% Fe. A series of techniques, including neutron diffraction, X-ray diffraction, electron backscattering diffraction as well as granulometric and imaging analysis of flotation concentrates were applied in this study. The results obtained through the textural and microstructural studies allow fitting different ores in your tectonic setting, into Quadrilátero Ferrífero. Additionally, the diversity of rheologic features defined by the different techniques led to define new correlation parameters with selectivity indices of flotation that can be applied to the iron ore processing industry, contributing to increase iron ore recovery. / Doutor

Orientador: Antenor Zanardo / Banca: Maria Margarita Torres Moreno / Banca: Marcio Raymundo Morelli / Resumo: O estudo do comportamento reológico de barbotinas com argilas da Formação Corumbataí, surgiu da necessidade das indústrias cerâmicas do Pólo de Santa Gertrudes se adaptarem às mudanças do comportamento mercadológico e ao aumento das exigências dos órgãos ambientais em relação aos riscos causados pela geração de poeira pelo processo de moagem via seca. Foram selecionadas três áreas geograficamente distantes, mas dentro do pólo, e foram feitas caracterizações mineralógicas e reológicas. Para o estudo reológico foram feitas medidas de viscosidade, tensão de cisalhamento e taxa de cisalhamento com viscosímetro rotacional, tendo como parâmetros de controle, o teor de sólidos da barbotina e a granulometria. Desta forma, foram obtidas curvas de defloculação e foram medidas variações nas suspensões, tais como o comportamento pseudoplástico e a tixotropia. Também foi analisada a dependência do comportamento reológico com a mineralogia das argilas, obtida por difração de raios X. Os resultados das curvas de fluxo e de viscosidade mostraram-se muito coerentes com a mineralogia determinada, indicando uma piora do comportamento reológico no sentido da base para o topo da Formação, bem como lateralmente, na dependência de alteração supérgena, permitindo avaliar o uso destas argilas no processo de preparação de massa via úmida. / Abstract: The study of rheological behavior of clay slips at Corumbataí Formation, arose from the need for the ceramic industries of Santa Gertrudes Pole to adapt to the changes of the market behavior and the demands of the environmental organs regarding the risks caused by the generation of dust, by the dry milling mass preparation. Three geographically distant regions were selected inside the area of the pole, mineralogical and rheological characterization were made. Viscosity measurements, shear stress and shear rate have been made with rotational viscometer, by having the solid content of the slip and particle size as control parameters. Therefore defloculation curves were made and variations of the suspensions have been verified, like the pseudoplastic behavior and the tixotropy. The dependence of the rheological behavior on the clay mineralogy has also been analyzed and it was obtained by X-ray diffraction. The results of the rheological curves appeared to be very coherent with the determined mineralogy, indicating a worsening of the rheological behavior from the bottom to the top of the formation, as well as laterally, in dependence on the superficial alteration, permitting to evaluate the use of these clays in the wet milling process. / Mestre