Made available in DSpace on 2016-12-08T16:44:38Z (GMT). No. of bitstreams: 1 PGPV08MA074.pdf: 1007571 bytes, checksum: c3134831f74786bb3ac41aa97b6f08e0 (MD5) Previous issue date: 2008-10-13 / The beans grains have an important role in the human nutrition, and in Brazil, they have a special importance, not only because Brazil is the biggest producer in the world, but also, for being a great consumer. For the programs of genetic breeding, the recommendation for new cultivars has been made because of its agronomics characteristic; however, these characteristics are so important as the technological quality and the nutritional potential of beans. In this context, were conducted three experiments and the objective was to evaluate technological quality (capacity of hydration and cooking time) and their relations with the standardization of cooking test in bean grain and evaluated the nutritional potential from genotypes associated with lower cooking time. In the first experiment, it was analyzed the cultivar BRS-Valente in four different types of water: pure water, distillate water, tap water and mineral water. The results showed 69% of hydration in two hours and it was the less cooking time, with pure water, distillate and tap water; the use of pure and distillate water during the cooking process proportionated a normal level of cooking resistance, the tap water had a different result and it causes a resistant level of cooking, while with the mineral water the time of cooking was very high. In the second experiment, twenty landraces genotypes and five commercial genotypes were evaluated according to their capacity of hydration in the point of stabilization, and in these times: 0, 2, 4, 6, 8 e 16 hours, determining the time of cooking. The results showed that it was possible to indicate 7 hours and 82,5% of hydration as a previous standard of hydration before the cooking test, for the earlier selection of lines, and also for the value for cultivation and use testing (VCU) of beans. In the third experiment, for the same genotypes from the anterior experiment, it was done the characterization related to the nutritional values: protein, phosphorus, potassium, calcium, magnesium, iron and zinc and their correlations to the hydration capacity and cooking time. There was a significative genetic variation for the values of phosphorus, magnesium and iron between the researched genotypes. The values and the respective variations for these nutrients were: 4,55 g.kg-1 (BAF112) to 6,63 g.kg-1 (BAF41) and 0,74 g.kg-1 (BAF11) to 1,13 g.kg-1 (BAF81) and 40,00 mg.kg-1 (BAF121) to 85,33 mg.kg-1 (BAF41), respectively. There was not a significative correlation between the nutrition value and the cooking time. The genotypes BAF s 04, 07, 58, 81, 84 e 97 had the highest level of protein and the BAF s 07, 41, 42 e 50 had the highest level of iron. These genotypes can be indicated for biofortification of diets or to be included in programs of genetic breeding, as well, can be indicated to the rural familiar agriculture / Os grãos de feijão ocupam importante papel na nutrição humana, e no Brasil tem especial importância, não somente por ser o maior produtor mundial, mas também por ser grande consumidor. Para os programas de melhoramento genético, a recomendação de novas cultivares tem sido realizada em função de suas características agronômicas, porém, tão importante quanto essas características está a qualidade tecnológica e o potencial nutricional dos grãos. Nesse contexto, foram conduzidos três experimentos com o objetivo de avaliar a qualidade tecnológica (capacidade de hidratação e tempo de cozimento), suas relações com a padronização do teste de cocção em grãos de feijão e o potencial nutricional dos genótipos associado ao menor tempo de cocção. No primeiro experimento, foi analisada a cultivar BRSValente em função de quatro tipos de água: ultra pura, destilada, torneira e mineral. Os resultados obtidos mostraram que um percentual de 69% de hidratação no tempo de 2 horas de hidratação foi indicativo de menor tempo de cocção, para as águas ultra pura, destilada e da torneira; o uso da água ultra pura e destilada durante o processo de cocção proporcionou um nível normal de resistência à cocção, enquanto que a água da torneira diferiu das demais e causou um nível resistente à cocção, enquanto que na água mineral o tempo de cocção foi muito elevado. No segundo experimento, vinte genótipos crioulos e cinco comerciais, foram avaliados quanto à capacidade de hidratação no ponto de estabilização, e nos tempos: 0, 2, 4, 6, 8 e 16 horas, determinando-se o tempo de cocção. Os resultados mostraram que foi possível indicar 7 horas e 82,5% de hidratação como padrão de hidratação prévia aos testes de cocção tanto para seleção precoce de linhagens, como nos ensaios de valor de cultivo e uso (VCU) de feijão. No terceiro experimento, para os mesmos genótipos do experimento anterior, foi realizada a caracterização quanto aos teores de nutrientes: proteína total, fósforo, potássio, cálcio, magnésio, ferro e zinco e suas correlações com a capacidade de hidratação e tempo de cozimento. Houve variabilidade genética significativa para teores de fósforo e magnésio e ferro entre os genótipos estudados. Os teores e respectivas variações para esses nutrientes foram: 4,55 g.kg-1 (BAF112) a 6,63 g.kg-1 (BAF41) e 0,74 g.kg-1 (BAF11) a 1,13 g.kg-1 (BAF81) e 40,00 mg.kg-1 (BAF121) a 85,33 mg.kg-1 (BAF41), respectivamente. Não se obteve correlação significativa entre teor de nutriente e tempo de cocção. Os genótipos BAF s 04, 07, 58, 81, 84 e 97, apresentaram maiores teores de proteína total e os BAF s 07, 41, 42 e 50, os maiores teores de ferro. Esses genótipos podem ser indicados na biofortificação de dietas ou para serem incluídos em programas de melhoramento, bem como, indicados para agricultura familiar rural

Submitted by Daniel Lucas Zago Caetano (daniel.caetano@sjrp.unesp.br) on 2017-09-29T00:38:30Z No. of bitstreams: 1 caetano_dlz_dr_sjrp.pdf: 13957655 bytes, checksum: 5b96587e7372ab57b53df4f703a1de39 (MD5) / Approved for entry into archive by Monique Sasaki (sayumi_sasaki@hotmail.com) on 2017-09-29T18:31:12Z (GMT) No. of bitstreams: 1 caetano_dlz_dr_sjrp.pdf: 13957655 bytes, checksum: 5b96587e7372ab57b53df4f703a1de39 (MD5) / Made available in DSpace on 2017-09-29T18:31:12Z (GMT). No. of bitstreams: 1 caetano_dlz_dr_sjrp.pdf: 13957655 bytes, checksum: 5b96587e7372ab57b53df4f703a1de39 (MD5) Previous issue date: 2017-09-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Este trabalho tem por objetivo estudar, por meio de simulações computacionais baseadas no método de Monte Carlo, interações eletrostáticas em superfícies e macromoléculas. Na primeira parte deste estudo é abordada a interação entre polieletrólitos, mais especificamente, homopolímeros e copolímeros em bloco suscetíveis à variações de pH, e macromoléculas com distribuição helicoidal de carga compatível com a encontrada em polinucleotídeos. A macromolécula foi representada por um cilindro rígido infinito que simula a parte central do DNA/RNA, totalmente inacessível ao polieletrólito. Visando simular os sulcos do DNA, duas esferas completam o modelo: uma localizada na posição dos grupos fosfato (esfera externa) e outra localizada entre a esfera externa e o cilindro (esfera interna). A distribuição de carga da macromolécula é dada por um conjunto de cargas negativas monovalentes centradas nas esferas externas. O polieletrólito foi representado por uma cadeia de N esferas rígidas carregadas, conectadas por um potencial harmônico e com um valor de pKa específico. A solução eletrolítica foi tratada pela teoria de Debye-Hückel. Os efeitos do pH, da concentração de sal, da estrutura primária e da rigidez da cadeia polimérica e da distribuição de carga da macromolécula sobre as propriedades conformacionais e físico-químicas da cadeia adsorvida foram calculados. Verificou-se que a presença da macromolécula modifica as propriedades ácido/base do polieletrólito e que o efeito de regulação de carga afeta o processo de adsorção/dessorção. Além disso, constatou-se uma dependência entre as conformações adotadas pelo polieletrólito na superfície da macromolécula e a concentração de sal da solução. Na segunda parte deste trabalho é investigada a influência das interações de hidratação sobre a capacitância diferencial da dupla camada elétrica por meio de simulações de Monte Carlo e por modelos teóricos baseados na aproximação de Campo Médio. Um eletrodo plano e carregado foi inserido em uma solução eletrolítica constituída por íons monovalentes e com concentração próxima às condições fisiológicas. As interações de hidratação foram descritas por meio de potenciais de Yukawa, as quais foram adicionadas às interações de Coulomb e de volume excluído entre os íons e entre os íons e o eletrodo. O modelo de Campo Médio proposto não só inclui interações de hidratação aos pares ânion-ânion, ânion-cátion e cátion-cátion de intensidades arbitrárias, mas também leva em consideração o tamanho finito dos íons por meio de duas abordagens distintas: i) equação de estado de Carnahan-Starling; e ii) modelo de rede. A capacitância diferencial obtida não só pelas simulações de Monte Carlo, mas também pelas aproximações de Campo Médio, apresenta o característico pico duplo, usualmente denominado de camel-shape, no qual seu decaimento reflete o empacotamento dos contraíons nas proximidades do eletrodo. Verificou-se também que a presença das interações de hidratação entre os íons e entre o eletrodo e os íons promove o surgimento de uma pequena região de depleção de carga nas proximidades do eletrodo, similar à camada de Stern. / This work aims to analyze electrostatic interactions on surfaces and macromolecules through the use of computational simulations based on the Monte Carlo method. In the first part of this study, we discuss the interaction between polyelectrolytes – more specifically homopolymers and block-copolymers which are susceptible to variations in pH – and macromolecules with helical charge distribution compatible with that found in polynucleotides. The macromolecule was represented by an infinite rigid cylinder, which mimics the central core of RNA/DNA, totally inaccessible to the polyelectrolyte. In order to simulate DNA grooves, two additional spheres complete the model: one being centered at the position of the phosphate groups (outer sphere) and the other being located between the outer sphere and the cylinder (inner sphere). The charge distribution of the macromolecule is given by a helical set of monovalent negative charges centered at the outer spheres. The polyelectrolyte was represented by a chain with charged hard spheres connected by harmonic bonds and presenting a specific pKa value. The electrolyte solution was treated at the Debye-Hückel level. The effects of pH, salt concentration, primary structure and stiffness of the polymer chain on the conformational and physicochemical properties of the adsorbed chain were investigated. Results show that the presence of the macromolecule modifies the acid/base properties of the polyelectrolyte and that the effect of charge regulation affects the adsorption/desorption process. Furthermore, a dependence between the conformations adopted by the polyelectrolyte on the surface of the macromolecule and the salt concentration of the solution was also observed. In the second part of this study, we investigated the influence of hydration interactions on the differential capacitance of an electric double layer by means of Monte Carlo simulations and by theoretical models based on mean-field approximation. A charged planar electrode was inserted in an electrolyte solution composed of monovalent ions and with concentration close to that found at physiological conditions. The hydration interactions were modeled through Yukawa potentials, which were added to Coulomb and excluded volume interactions among the ions and between the ions and the electrode. The proposed mean-field model not only include hydration interactions to the cation-cation, anion-anion and cationanion pairs, but also take into account the finite size of the ions through two distinct approaches: i) the Carnahan-Starling equation of state, and ii) the lattice gas model. We found that both our Monte Carlo simulations and mean-field approaches predict a characteristic double-peak (the so-called camel shape) of the differential capacitance, where its decrease reflects the packing of the counterions near the electrode. We also found that the presence of hydration interactions among the ions and between the ions and the electrode promotes the emergence of a small region of charge depletion near the electrode, similar to the Stern layer. / FAPESP: 2013/13151-7

Esta pesquisa trata da estabilização de misturas de agregados reciclados por meio da ativação de seus finos, cujas composições possibilitam a ocorrência de reações químicas de cimentação. Para o desenvolvimento da pesquisa foram utilizados dois tipos de agregados reciclados: um proveniente de resíduo de demolição de natureza cimentícia e outro da indústria de cerâmica vermelha. O uso dos materiais foi feito por meio de dosagens para obtenção de misturas cujas combinações de materiais pudessem, quimicamente, potencializar a ocorrência de hidratação do cimento anidro existente nos finos do agregado reciclado cimentício e de reação pozolânica pela pozolanicidade da cerâmica vermelha. Com isso foram obtidas cinco misturas, compostas pelos agregados reciclados em estudo misturados entre si e com a adição de aglomerantes hidráulicos, sobre as quais foram realizados ensaios em laboratório para verificação da ocorrência das reações químicas esperadas com consequente estabilização das misturas, de modo a influenciar nos respectivos comportamentos mecânicos. Também foi realizada a avaliação de características do empacotamento dos grãos como forma de verificar se o arranjo físico, neste caso, exerce influência significativa na melhora do comportamento mecânico das misturas estudadas. Os resultados obtidos indicaram que, de fato, ocorreram as reações químicas esperadas, comprovadas pelos resultados dos ensaios de termogravimetria e difração de raios x, realizados em três diferentes idades de cura. Verificou-se, também, a melhora no comportamento mecânico das misturas por meio do aumento da resistência à compressão simples e do módulo de resiliência com a evolução da cura, além de baixa deformabilidade aos 91 dias de cura. Com isso foi comprovada a estabilização das misturas em estudo, com a consequente melhora de seus desempenhos, sendo devida, principalmente, à ocorrência das reações químicas de hidratação do cimento anidro e pozolânica. A pesquisa demonstrou a possibilidade de se estabilizar misturas de agregados reciclados cimentícios e de cerâmica vermelha por meio da ocorrência de reações químicas de cimentação promovidas pela combinação destes materiais. / This research deals with the stabilization of mixtures constituted by recycled aggregates through the activation of its fines portions, whose components enable the occurrence of chemical cementation reactions. In order to develop this research, two types of recycled aggregates were used: one from demolition waste with cementitious origin, and the other one from the red ceramic industry. The use of these materials was done through mix designs to obtain mixtures whose combinations of materials could chemically increase the occurrence of hydration of the anhydrous existing in fine portion of the recycled cementitious aggregates, and pozzolanic reactions due to the pozzolanicity of red ceramics. Thus, five mixtures were obtained, and they were composed by the studied recycled aggregates, mixed together and with the addition of hydraulic binders, on which laboratory tests were performed in order to verify the occurrence of the expected chemical reactions with consequent stabilization of the mixtures, in order to influence their mechanical behavior. Furthermore, it was performed the evaluation of packing characteristics of the particles to verify if the physical arrangement, in this case, has any significant influence on improving the mechanical behavior of the mixtures studied. The results obtained indicated that in fact the expected chemical reactions occurred, which was verified by the results from thermogravimetry and X-ray diffraction tests performed at three different times of curing. The improvement of the mixtures mechanical behavior by increasing of their compressive strength and their resilient modulus was also verified as the mixtures were cured, in addition to low deformability at 91 days of curing. Thus, the stabilization of the mixtures studied was confirmed, which was mainly due to the occurrence of chemical hydration reactions of the anhydrous cement and pozzolanic reactions. The study demonstrated the possibility of stabilizing mixtures of recycled aggregates cementitious waste and red ceramic by the occurrence of cementing chemical reactions promoted by combination of these materials.

Made available in DSpace on 2014-10-09T12:36:01Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:48Z (GMT). No. of bitstreams: 0 / Pasta de cimento é um material comum em repositórios para rejeitos radioativos, atuando como material estrutural e de imobilização. Sua utilização como material de preenchimento em um repositório tipo poço tubular profundo para fontes seladas, no entanto, requer um maior tempo de vida útil do material. O conhecimento de seu comportamento em longo prazo é necessário para garantir a segurança da instalação em milhares de anos. O presente trabalho avaliou as alterações na pasta de cimento induzidas por fatores de degradação, como ataque de agentes agressivos, alta temperatura e presença de campo de radiação. Corpos de prova (cps) de pasta de cimento foram submetidos a ensaios acelerados de degradação e os efeitos deletérios foram avaliados por meio de ensaios de resistência mecânica, variação dimensional, lixiviação/penetração de íons, DRX, TGA e MEV. Observou-se que a hidratação dos cps foi beneficiada pela imersão (em água destilada ou em solução salina) e alta temperatura, resultando em uma resistência maior. O armazenamento à seco prejudicou a hidratação, mantendo a resistência mais baixa. O tempo de imersão e a irradiação não foram capazes de alterar a mineralogia e a resistência da pasta de cimento. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Submitted by Erika Demachki (erikademachki@gmail.com) on 2014-10-20T18:04:26Z No. of bitstreams: 2 Dissertação - Flávio Mamede Pereira Gomes - 2011.pdf: 8664342 bytes, checksum: ec6aaf6a4d8eea743adbadcdd5346581 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Jaqueline Silva (jtas29@gmail.com) on 2014-10-20T18:43:47Z (GMT) No. of bitstreams: 2 Dissertação - Flávio Mamede Pereira Gomes - 2011.pdf: 8664342 bytes, checksum: ec6aaf6a4d8eea743adbadcdd5346581 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2014-10-20T18:43:47Z (GMT). No. of bitstreams: 2 Dissertação - Flávio Mamede Pereira Gomes - 2011.pdf: 8664342 bytes, checksum: ec6aaf6a4d8eea743adbadcdd5346581 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2011-11-18 / Large dimension concrete structures or those with restrictive conditions for heat dissipation are particularly subject to cracking in the early ages. Several phenomena may occur simultaneously, such as autogenous reactions, plastic shrinkage or drying, and temperature variations, leading to deformations which may be the main cause of cracking in the early ages of concrete, if the structure is restrained. Thus, the behavior of the concrete must be satisfactorily modeled and foreseen. The thermal and mechanic properties of concrete can be determined by standard tests or by prediction models, depending on the time and values established for the remaining thermal properties. The calculation methodology may become complex, considering the influence of temperature in the exothermic of the reaction, within the theoretical framework of the thermo-chemical-mechanical couplings. However, it may be simplified, as it is the aim of this paper to demonstrate. As for the mechanical behavior, concrete is considered a viscoelastic material. The simplifications are adopted in relation to the resources and time available, or in relation to the specifications of the problem to be modeled. The modeling of the concrete structures with simple geometry in the early ages, such as reservoirs, foundation block or retaining walls is made by considering the material simply as elastic for purpose learning the coefficient of restrain, which correlates the tension in a certain point of the structure to the tension in a restrained bar. This allows a swifter calculation of thermal tensions in a specific point in the structure, based solely in the history of temperature and degree of restrain, in addition to the properties of the material, which is valid for some boundary situations. This enables the technical personnel not specialized to access relevant information about preventive and mitigating measures to be adopted against undesirable effects. / Estruturas de concreto de dimensões suficientemente grandes ou com restritas condições de dissipação de calor, estão particularmente sujeitas à fissuração nas primeiras idades. Diversos fenomenos ocorrendo simultaneamente, tais como retração autógena, retração plástica ou de secagem, variações de temperatura, provocam deformações que podem ser a principal causa de fissuração do concreto jovem, caso a estrutura esteja restringida, devendo ter o comportamento satisfatoriamente modelado e previsto. As propriedades térmicas e mecânicas do concreto podem ser determinadas por ensaios normatizados ou por modelos previsores das propriedades dependentes do tempo e valores tabelados para as demais propriedades térmicas. A metodologia de cálculo pode se tornar complexa, considerando a influência da temperatura na exotermia da reação, dentro do quadro teórico dos acoplamentos termo-químico-mecânicos, ou pode ser realizada de maneira simplificada, que é o objeto desta dissertação. Quanto ao comportamento mecânico, o concreto é considerado material viscoelástico. Simplificações são adotadas em função de recursos e tempo disponíveis, ou em função de especificidades do problema a ser modelado. A modelagem de estruturas de concreto nas primeiras idades com geometrias simples, tais como laje de reservatório, blocos de fundação e muros de arrimo, é realizada considerando o material simplesmente elástico para efeito do conhecimento do coeficiente de restrição, que correlaciona a tensão em um ponto da estrutura à tensão de uma barra restringida. Isto permite o cálculo expedito de tensões de origem térmica de um ponto da estrutura, baseado apenas no histórico de temperaturas e do grau de restrição, além é claro das propriedades do material, validada para algumas situações de contorno, disponibilizando ao meio técnico não especializado informações relevantes sobre medidas preventivas e mitigadoras de efeitos indesejáveis a serem adotadas.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2017-12-13T11:59:28Z No. of bitstreams: 2 Dissertação - Patrícia Guedes Gambale - 2017.pdf: 11002358 bytes, checksum: 0a8a575fbc0c16340994402f2059944c (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-12-13T12:00:08Z (GMT) No. of bitstreams: 2 Dissertação - Patrícia Guedes Gambale - 2017.pdf: 11002358 bytes, checksum: 0a8a575fbc0c16340994402f2059944c (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-12-13T12:00:08Z (GMT). No. of bitstreams: 2 Dissertação - Patrícia Guedes Gambale - 2017.pdf: 11002358 bytes, checksum: 0a8a575fbc0c16340994402f2059944c (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-08-31 / Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG / The advancement of concrete technologies and methods of structural calculation nowadays makes buildings increasingly challenging, especially from the point of view of foundations. Foundation blocks with great volumes need attention as to the fissures arising from the exothermic process of hydration of the concrete, this concern defines the mixture as mass concrete, a widespread term in the construction of dams and that has been gaining space in urban civil construction. This study proposes the monitoring of prototypes of concrete blocks developed in the laboratory and foundation block in the field, with the use of thermocouples comparing with numerical methods of finite elements aiming to improve the prediction of cracks and to develop techniques so that they are avoided. This study will analyze the influence of the type and consumption of cement in the emergence of tensions arising from the energy released during its hydration. As results, a relation of the type interference and cement consumption is presented through the monitoring and analysis of the foundation block prototypes developed in the research, the development of a simplified unidirectional model of temperature and voltage prediction due to the heat of hydration for to evaluate the maximum temperature reached and the potential of cracking in the concrete mass and the comparison between the temperature results obtained in the Ansys program, which uses three- dimensional modeling and, as a way of validating the predictive model of thermal behavior as a reliable tool of analysis, the study also presents a field monitoring of a foundation block of a construction located in Goiânia and later application of the forecast model and the Ansys program. It was found, therefore, that the cement type has a considerable influence on the compressive strength and the adiabatic elevation, the latter being less significant. As for the cement consumption analysis, there was a notable increase in temperature in the concrete with higher consumption, causing cracks in the analyzed structure. By means of the results presented by the Ansys program, the monitoring of the prototypes and block in the field and the proposed forecast model, the validation of this model was confirmed as a good predictive tool of thermal behavior, highlighting some limiting conditions that surround it. / O avanço das tecnologias do concreto e dos métodos de cálculo estrutural possibilita, nos dias atuais, edifícios cada vez mais desafiadores, principalmente do ponto de vista das fundações. Blocos de fundações de grandes volumes, definidos como concreto massa, carecem de atenção quanto às fissuras advindas do processo exotérmico de hidratação do concreto, estapreocupação atualmente é bastante difundida na construção de barragens e que vem ganhando espaço na construção civil urbana. Este trabalho propõe o monitoramento de protótipos de blocos de concreto desenvolvidos em laboratório e bloco de fundação em campo, com o uso de termopares comparando com métodos numéricos de elementos finitos objetivando aprimorar a previsão de fissuras e desenvolver técnicas para que estas sejam evitadas. O trabalho analisará a influência do tipo e consumo de cimento na liberação de calor e no surgimento de tensões advindas da energia liberada durante sua hidratação. Como resultados, são apresentados uma relação da interferência dos tipos e consumo de cimento por meio do monitoramento e análise dos protótipos de blocos de fundação desenvolvidos na pesquisa, o desenvolvimento de um modelo simplificado unidirecional de previsão de temperatura e tensão devido ao calor de hidratação para avaliar a temperatura máxima atingida e o potencial de fissuração no concreto massa e a comparação entre os resultados de temperatura obtidos no programa Ansys, que utiliza modelagem tridimensional e, como forma de validar o modelo preditivo do comportamento térmico como ferramenta confiável de análise, o trabalho também apresenta um monitoramento em campo de um bloco de fundação de uma obra localizada Goiânia e posterior aplicação do modelo de previsão e do programa Ansys. Verificou-se, assim, que o tipo de cimento influencia de maneira considerável na resistência à compressão e na elevação adiabática, sendo a última menos significativa. Quanto a análise de consumo de cimento, verificou-se um aumento notável de temperatura no concreto com maior consumo, ocasionando fissuras na estrutura analisada. Por meio dos resultados apresentados pelo programa Ansys, o monitoramento dos protótipos e bloco em campo e o modelo de previsão proposto, confirmou-se a validação do referido modelo como boa ferramenta pretidiva de comportamento térmico, ressaltando algumas condições limitantes que o cercam.

Atualmente doenças ocupacionais manifestadas nas mãos, como hiperqueratinização, escamação, desidratação e fissuras profundas são frequentemente relatadas por profissionais como médicos, enfermeiros, dentistas, mecânicos e donas de casa. O uso frequente de luvas e o contato constante com substâncias químicas como detergentes e sabões são as principais causas. O tratamento é feito pelo uso de corticóides tópicos, o que a longo prazo pode causar aumento das infecções no local de aplicação, devido ao efeito colateral de inibição do sistema imune destes fármacos. Isto exposto, fica evidenciada a importância da profilaxia e boa hidratação como alternativas de tratamento. O emprego de matérias-primas vegetais em formulações cosméticas atende ao apelo de sustentabilidade e biocompatibilidade tão buscado pelas empresas do setor. Óleos como o de andiroba e copaíba são tradicionalmente empregados pois podem apresentar potencial antibiótico e antiinflamatório. As manteigas de cacau e cupuaçu possuem alto teor de ácidos graxos, o que lhes confere potencial poder hidratante. Óleos e manteigas vegetais apresentam ainda potencial na formação de estruturas lamelares, as quais melhoram a estabilidade e aumentam o poder hidratante da formulação onde estão presentes. Esta pesquisa teve como objetivo o desenvolvimento de um creme à base de matérias primas vegetais, destinado à profissionais acometidos de doenças ocupacionais nas mãos. Foram manipuladas formulações com os óleos de copaíba e andiroba, aditivadas de manteigas de cacau e cupuaçu. Diversos pares de tensoativo foram pesquisados a fim empregar aquele que produzisse melhor estabilidade e permitisse a formação de estruturas lamelares. Quando empregados os tensoativos PEG-80 Sorbitan Laurate / Steareth-2 em emulsões com valores de EHL final 7 e 9, foi obtida boa estabilidade preliminar e observada presença de estruturas lamelares. Foi avaliado o comportamento destas frente à evaporação da água e foi observado que mesmo em pequenas concentrações ou após evaporação da água livre do sistema, as estruturas lamelares se mantêm presentes, sugerindo armazenamento de água entre as lamelas. A caracterização por difração de raios-X em alto ângulo (WAXS) permitiu observar que as cadeias carbônicas que compõem a bicamada ao redor dos glóbulos internos da emulsão estão dispostas em um estado ordenado denominado fase gel. A análise por difração de raio-X a baixo ângulo (SAXS) confirmou que os tensoativos estão organizados em multicamadas lamelares intercaladas por camadas de água que se mantiveram estáveis mesmo após três meses de envelhecimento em temperatura ambiente. A avaliação reológica mostrou comportamento pseudo-plástico com tixotropia e ligeiro aumento da viscosidade com o tempo, porém, não confirmou boa estabilidade. Por meio dos testes in vivo observou-se que as formulações desenvolvidas promoveram aumento da hidratação a qual foi prolongada em relação à formulação de mercado. / Currently occupational diseases manifested in the hands, as hyperkeratinazation, scaling, dehydration and deep fissures are frequently reported by professionals such as doctors, nurses, dentists, mechanics and housewives. The frequent use of gloves and constant contact with chemical such as detergents and soaps are the main cause. The treatment is done by the use of topical steroids, which in the long term may cause increased infections in the application site, due to side effect of inhibiting the immune system of these drugs. This exposed, the importance of proper hydration as prophylaxis and treatment alternatives is evidenced. The use of vegetable raw materials in cosmetic formulations attends the sustainability and biocompatibility appeal so sought by the cosmetics business sector. Oils such as Andiroba and Copaiba are traditionally used for their antibiotic and anti-inflammatory potential. Cocoa and Cupuassu butters have high levels of fatty acids, giving them potential moisturizing power. Vegetable oils and butters have yet a potential in formation of lamellar structures, which improve stability and increase the moisturizing power of the formulations where they are present. This research aimed to develop a cream based on vegetable raw materials destined to professionals suffering from occupational disease in the hands. Formulations were manipulated with Copaiba and Andiroba oils added with Cocoa and Cupassu butter. Several pairs of surfactant were investigated to employ one that produces better stability and allow the formation of anisotropic lamellar structures. When employed the following pair of surfactants PEG-80 Sorbitan Laurate / Steareth-2 in emulsions with required HLB of 7 and 9, good preliminary stability was obtained and lamellar structures were observed. We evaluated their behavior against water evaporation and we observed that even in small concentrations or after free water evaporation, lamellar structures are still present, suggesting water storage between the lamellae. Characterization by X-ray diffraction at wide angle (WAXS) elucidated that he carbon chains composing the bilayer around the emulsions internal globules are disposed in an ordered state called gel phase. The analysis by small angle X-ray diffraction (SAXS) confirmed that the surfactants are arranged in multilayered lamellae intercalated by layers of water that remained stable even after three months aging at room temperature. The rheological evaluation showed pseudo-plastic behavior with thixotropy and slight increase in viscosity with time, however, not confirmed good stability. The in vivo tests showed that the formulations caused an increase in hydration which was prolonged in relation to the formulation from the market.

Abstract : Wastepaper sludge ash (WSA) is generated by a cogeneration station by burning wastepaper sludge. It mainly consists of amorphous aluminosilicate phase, anhydrite, gehlenite, calcite, lime, C2S, C3A, quartz, anorthite, traces of mayenite. Because of its free lime content (~10%), WSA suspension has a high pH (13). Previous researchers have found that the WSA composition has poor robustness and the variations lead to some unsoundness for Portland cement (PC) blended WSA concrete. This thesis focused on the use of WSA in different types of concrete mixes to avoid the deleterious effect of the expansion due to the WSA hydration. As a result, WSA were used in making alkali-activated materials (AAMs) as a precursor source and as a potential activator in consideration of its amorphous content and the high alkaline nature. Moreover, the autogenous shrinkage behavior of PC concrete at low w/b ratio was used in order to compensate the expansion effect due to WSA. The concrete properties as well as the volume change were investigated for the modified WSA blended concrete. The reaction mechanism and microstructure of newly formed binder were evaluated by X-ray diffraction (XRD), calorimetry, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). When WSA was used as precursor, the results showed incompatible reaction between WSA and alkaline solution. The mixtures were not workable and provided very low compressive strength no matter what kinds of chemical activators were used. This was due to the metallic aluminum in WSA, which releases abundant hydrogen gas when WSA reacts with strong alkaline solution. Besides, the results of this thesis showed that WSA can activate the glassy phase contained in slag, glass powder (GP) and class F fly ash (FFA) with an optimum blended ratio of 50:50. The WSA/slag (mass ratio of 50:50) mortar (w/b of 0.47) attained 46 MPa at 28 days without heat curing assistance. A significant fast setting was noticed for the WSA-activated binder due to the C3A phase, free lime and metallic aluminum contained in the WSA. Adding 5% of gypsum can delay the fast setting, but this greatly increased the potential risk of intern sulfate attack. The XRD, TGA and calorimetry analyses demonstrated the formation of ettringite, C-S-H, portlandite, hydrogarnet and calcium carboaluminate in the hydrated binder. The mechanical performance of different binder was closely related to the microstructure of corresponding binder which was proved by the SEM observation. The hydrated WSA/slag and WSA/FFA binder formed a C-A-S-H type of gel with lower Ca/Si ratio (0.47~1.6). A hybrid gel (i.e. C-N-A-S-H) was observed for the WSA/GP binder with a very low Ca/Si ratio (0.26) and Na/Si ratio (0.03). The SEM/EDX analyses displayed the formation of expansive gel (ettringite and thaumasite) in the gypsum added WSA/slag concrete. The gradual emission of hydrogen gas due to the reaction of WSA with alkaline environment significantly increased the porosity and degraded the microstructure of hydrated matrix after the setting. In the last phase of this research WSA-PC blended binder was tailored to form a high autogenous shrinkage concrete in order to compensate the initial expansion. Different binders were proportioned with PC, WSA, silica fume or slag. The microstructure and mechanical properties of concrete can be improved by decreasing w/b ratios and by incorporating silica fume or slag. The 28-day compressive strength of WSA-blended concrete was above 22 MPa and reached 45 MPa when silica fume was added. The PC concrete incorporating silica fume or slag tended to develop higher autogenous shrinkage at low w/b ratios, and thus the ternary binder with the addition of WSA inhibited the long term shrinkage due to the initial expansion property to WSA. In the restrained shrinkage test, the concrete ring incorporating the ternary binder (PC/WSA/slag) revealed negligible potential to cracking up to 96 days as a result of the offset effect by WSA expansion. The WSA blended regular concrete could be produced for potential applications with reduced expansion, good mechanical property and lower permeability. / Résumé : Les cendres de boues de désencrage (CBD) sont générées par une centrale de cogénération par combustion boues de désencrage. Ils se composent principalement de phase amorphe d'aluminosilicate, anhydrite, gehlenite, calcite, chaux, C2S, C3A, quartz, anorthite, des traces de mayénite. En raison de leur teneur en chaux libre (~ 10%), CBD ont un pH élevé (13). Les chercheurs précédents ont montré que la composition des CDB a une mauvaise robustesse et les variations conduisent à une certaine inconsistance pour le béton avec un mélange de ciment Portland (CP) et des CBD. Cette thèse a porté sur l'utilisation des CBD dans différents types de mélanges de béton pour éviter l'effet délétère de l'expansion due à l'hydratation des CBD. Par conséquent, les CBD ont été utilisées dans la fabrication des matériaux à activation alcaline (MAA), en tant que source précurseur et comme activateur potentiel en tenant compte de sa teneur en matière amorphe et la nature très alcaline des CBD. De plus, le retrait endogène du béton avec CP à faible rapport E/L a été utilisé afin de compenser l'effet d'expansion en raison des CBD. Les propriétés du béton ainsi que le changement de volume ont été étudiés pour le béton mélangé avec des CBD modifiés. Le mécanisme réactionnel et la microstructure du liant nouvellement formé a été évaluée par la diffraction aux rayons X diffraction (DRX), calorimétrie, l'analyse thermogravimétrique (ATG), microscopie électronique à balayage (MEB) et spectroscopie à dispersion d'énergie aux rayons X (DEX). Quand les CBD ont été utilisés comme précurseur, les résultats ont montré des réactions incompatibles entre CBD et une solution alcaline. Les mélanges ne sont pas maniables et donnent de très faibles résistances en compression, peu importe le type d'activateurs chimiques utilisés. Cela est dû à l'aluminium métallique dans les CBD, qui permet de libérer de l'hydrogène gazeux en abondance quand les CBD réagissent avec une solution alcaline forte. D'ailleurs, les résultats de ces recherches ont montré que les CBD peuvent activer la phase amorphe contenue dans le laitier, poudre de verre (PV) et les cendres volantes de classe F (CVF) avec un rapport de mélange optimal de 50:50. Un mortier avec un rapport massique 50:50 de CBD et de laitier (E/L de 0,47) atteint 46 MPa à 28 jours sans l’aide d’un murissement à chaud. Une prise rapide significative a été notée pour le liant CBD activé en raison de la phase C3A, chaux libre et l’aluminium métallique impliqué dans les CBD. L’ajout de 5% de gypse peut retarder la prise rapide, mais augmente grandement le risque potentiel de l’attaque au sulfate interne. Le DRX, ATG et l’analyse calorimétrique ont démontré la formation d'ettringite, C-S-H, la portlandite, hydrogrenat et carboaluminate de calcium dans le liant hydraté. Les différentes performances mécaniques du liant ont été étroitement liées à la microstructure correspondante qui a été prouvée par le MEB. Les liants hydratés CBD/laitier et CBD/CVF ont formé un type de gel C-A-S-H avec un faible rapport Ca/Si (0,47 ~ 1,6). On a observé un gel hybride (à savoir C-N-A-S-H) pour le liant CBD/PV avec un des très faibles rapports Ca/Si (0,26) et Na/Si (0,03). Les analyses MEB/DRX ont montré une formation de gel expansive (d’ettringite et de thaumasite) dans le gypse ajouté au béton avec les CBD et le laitier. L'émission progressive de l'hydrogène gazeux en raison de la réaction des CBD dans un environnement alcaline a augmenté la porosité et la dégradation de la microstructure de matrice hydratée après la prise. Dans la dernière phase de cette recherche, le liant avec un mélange de CBD et de CP a été développé pour former un retrait autogène élevé, afin de compenser l'expansion initiale. Différents liants ont été préparés avec le CP, CBD, la fumée de silice ou du laitier. La microstructure et les propriétés mécaniques du béton peuvent être améliorées en diminuant les rapports E/L et en incorporant la fumée de silice ou du laitier. La résistance en compression à 28 jours du béton aux CBD était supérieure à 22 MPa et atteint 45MPa lorsqu'on a ajouté de la fumée de silice. Le béton avec du CP incorporant de la fumée de silice ou du laitier ont tendance à développer un retrait endogène plus élevée à de faibles rapports E/L, et donc le liant ternaire avec l'ajout des CBD réduit le retrait à long terme en raison de la propriété d’expansion initiale des CBD. Dans l'essai de retrait empêché, l'anneau en béton incorporant le liant ternaire (CP/CBD/laitier) a révélé un potentiel négligeable à la fissuration jusqu'à 96 jours en raison de l'effet de décalage de l'expansion des CBD. Des liants modifiés avec des CBD peuvent être utilisés dans des mélanges de béton ordinaire pour des applications potentielles avec des expansions réduites, des bonnes propriétés mécaniques et une faible perméabilité.

In respect of autogenous and drying shrinkage and the effects of relaxation creep during the hydration cycle, roller compacted concrete in dams has to date been universally assumed to behave in the same manner as conventional mass concrete, despite notional evidence to the contrary on prototype dam structures, particularly in respect of high-paste RCC. While the results of laboratory materials testing and associated early behaviour analyses for RCC have been published, no conclusive example exists in the public domain whereby predicted behaviour is confirmed through measured behaviour on a comprehensively-instrumented prototype dam structure. In his PhD thesis, Quentin Shaw presents evidence to indicate that the early behaviour of RCC, and particularly high quality, high-paste RCC in dams, is quite different to that of CVC. Referring to instrumentation records from Wolwedans and Knellpoort dams in South Africa, Çine Dam in Turkey, Wadi Dayqah Dam in Oman and Changuinola 1 Dam in Panama, indications of less than expected shrinkage and stress relaxation creep during the hydration cycle in the constituent RCC are documented. Taking the comprehensively-instrumented and monitored Wolwedans Dam, the actual materials behaviour of the constituent RCC is evaluated through the replication of the prototype behaviour on a finite element model. Through this analysis, it is clearly demonstrated that the level of shrinkage and stress relaxation creep that would be traditionally assumed in RCC simply did not occur. In fact, the analyses suggested that no shrinkage, or creep was apparent. The reasons for the different behaviour of high-paste RCC compared to CVC are subsequently explored. With Wadi Dayqah Dam as the only example evaluated where some drying shrinkage and/or stress relaxation creep was obviously apparent, the evident susceptibility of this lean RCC mix, with a high w/c ratio, a high content of non-cementitious fines, natural gravel aggregates, a high aggregate water absorption and placement in a very dry environment, is noted. However, it is considered to be the combination of a strong aggregate skeletal structure developed through roller compaction and a low w/c ratio that results in a particularly resilience in high-paste RCC to early shrinkage and creep. It is also recognised that temperature and gravity effects in an arch dam structure will tend to limit, or even eliminate containment stresses in the critical load-carrying upper section and that this will reduce the risk and impact of stress relaxation creep. Consequently, a new understanding of the early behaviour of RCC in large dams is presented, suggesting that a high quality RCC mix in an arch dam can be designed for a cumulative shrinkage and stress relaxation creep under the hydration cycle of approximately 20 microstrain, compared with a more traditionally accepted value of between 125 and 200 microstrain. The implications of these findings on the design of large RCC dams are demonstrated to be significant, particularly in respect of RCC arch dams. In addition, suggestions are made for the requirements in respect of RCC mix design for negligible shrinkage and creep, while an approach to combine the use of field measurement with structural modelling to predict and demonstrate actual RCC behaviour is briefly discussed. / Thesis (PhD)--University of Pretoria, 2011. / Civil Engineering / unrestricted

Teeth trauma has become one of the most serious physical problems that people are suffering from in the past years. Early diagnosis and management are desperately needed to improve tooth survival, functionality and avoid the tooth loss. However, the diagnosis of cracked tooth could be challenging due to the small size of the crack. Therefore, a mechanics understanding of the tooth fracture is demanding from the perspective of developing a framework for failure prediction in clinical research and bio-mimetic restorative materials. This study focuses on characterising the anisotropic fracture behaviour and the crack shielding mechanisms in elephant dentin. This is often used as a structural analogue for human dentin due to the similarities in microstructure and chemical composition, in order to avoid the test-piece size restrictions, given the larger size of ivory than human teeth. Compact tension test-pieces were extracted from different locations on the ivory tusk so as to have different crack growth directions relative to the microstructure to inspect the fracture anisotropies. The fracture toughness as a function of the crack extension was assessed in terms of fracture resistance curves (R-curve). The accumulative crack-tip strain fields were also measured for the first time in dentin using digital image correlation technique (DIC) to investigate the capability of crack-tip elastic/plastic deformation before material failure. Investigation of crack morphologies, the interaction between crack and the microstructures, the fracture surfaces using both 2-D and 3-D techniques could provide with insights into extrinsic shielding mechanisms. Surface and volume crack opening displacement (COD) were measured for the first time optically and by X-ray computed tomography to investigate the effect of extrinsic crack-tip shielding. The displacement fields around the crack-tip obtained by DIC were fitted using Westergaard’s analytical solution to extract the effective stress intensity factor, by comparing this to the applied load, the efficiency of the crack-tip shielding could be evaluated. A novel cohesive element model (traction-separation law) was then established based on the COD results to simulate the physical process of crack-tip shielding. It is the first time the cohesive model has been adapted to studying the direct crack behaviour measured by in-situ experiment to predict the crack growth. This model was then validated using the crack-tip strain field and R-curve obtained from the experiment measurement.