Made available in DSpace on 2016-12-23T14:05:51Z (GMT). No. of bitstreams: 1 Ana Paula Milagres Trovao.pdf: 5557007 bytes, checksum: b2950e914a7a368c32f59e43ed00eb12 (MD5) Previous issue date: 2012-08-10 / The use of plaster in civil construction generates a large amount of waste, but it is a material that posses properties that makes it a highly competitive product. The main cause of the generation of this waste is the rapid hardening of the pastes. The incorporation of waste gypsum into the gypsum pastes results in an acceleration of the hardening process, which might increase the volume of residues generated. This dissertation aimed to develop procedure to incorporate the gypsum residue into plaster pastes without compromising the paste mechanical properties and, especially without accelerating its hardening process. Tests have been developed to evaluate the plaster pastes setting time, consistency, workability and temperature reading in the plaster pastes in the fresh state and evaluate the hardness and axial compressive strength in the hardened state. Tests results showed the viability of the incorporation of 5% gypsum waste in substitution of gypsum in the plaster paste when combined with borax retardant additive, which promoted extension of the workable time of the paste and an increase in the pastes mechanical properties / A utilização do gesso pela construção civil gera um grande volume de resíduos, no entanto é um material que apresenta propriedades que o torna altamente competitivo no mercado. A principal causa da geração desse resíduo é o rápido endurecimento das pastas. A incorporação de resíduo de gesso às pastas provoca a aceleração no processo de endurecimento, podendo aumentar ainda mais o volume de resíduos gerados. Essa dissertação teve como objetivo buscar a forma de incorporação do resíduo às pastas de gesso para revestimento de parede, sem comprometer suas propriedades mecânicas e principalmente não acelerar seu endurecimento. Foram realizados os ensaios de tempo de pega, consistência, consistência útil e leitura de temperatura nas pastas em seu estado fresco além dos ensaios de dureza e compressão axial destas no estado endurecido. Os ensaios apontaram a viabilidade da incorporação de 5% de resíduo de gesso em substituição do gesso quando associado ao aditivo retardador bórax, que promoveu ampliação do tempo de utilização da pasta e o aumento nas propriedades mecânicas ensaiadas

Orientador: Jose Antonio Malmonge / Resumo: O uso de materiais inteligentes tem sido cada vez mais utilizado pelo ramo de engenharia civil, devido à crescente demanda por construções que têm como função não só atenderem ao crescente aumento populacional, como agirem também como facilitadores da vida humana. Dentro dos estudos em desenvolvimento nesta área, o que vem ganhando destaque é o desenvolvimento de sensores compósitos de materiais piezoelétricos à base de cimento, que sejam capazes de atuar no monitoramento e detecção de possíveis falhas nas estruturas civis em tempo real e contínuo. Alguns dos grandes problemas encontrados no desenvolvimento de sensores piezoelétricos baseados em matrizes cimentícias, encontram se na degradação das propriedades dos sensores frente às condições ambientais em tempo contínuo a que estes são submetidos, bem como, a possibilidades de as fases de preenchimento interferirem diretamente no processo de cura da matriz, reduzindo suas propriedades mecânicas desejáveis. Buscando resolver tais problemas, o presente trabalho teve como objetivo a obtenção e caracterização de compósitos piezoelétricos utilizando como matriz o cimento modificado com borracha natural (BN) e titanato zirconato de chumbo (PZT) como fase piezoelétrica. O PZT foi escolhido como fase piezoelétrica devido seu alto valor do coeficiente piezoelétrico enquanto a inserção da BN buscou garantir aos compósitos, resistência à passagem de água, umidade e a resistência a soluções nocivas ao cimento, atuando no aumento da dura... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The use of intelligent materials has been increasingly used by the civil engineering industry, in response to the increasing demand for constructions that serve, not only to attend to the increasing population, but also to act as facilitators of human life. Within the studies under development in this area, the one that has being gaining prominence is the development of composite sensors of cement-based piezoelectric materials, that can act in the monitoring and detection of possible failures in civil structures in real and continuous time. Some of the major problems encountered in the development of piezoelectric sensors based on cementitious matrices lie in the degradation of the properties of the sensors, both as against the environmental conditions in continuous time to which they are subjected, as well as the possibility that filling phases interfere directly in the process of curing the matrix, reducing its desirable mechanical properties. In order to solve such problems, the present study aimed to obtain and characterize of a composite piezoelectric array of modified cement with natural rubber (NR) and lead zirconate titanate (PZT) as the piezoelectric layer. The PZT was chosen as the piezoelectric phase because of its high piezoelectric coefficient, while the BN insertion sought to guarantee the resistance of the composites to the passage of water, moisture and noxious solutions to the cement, in order to increase not only the durability, as well the piezoeletric prop... (Complete abstract click electronic access below) / Mestre

Made available in DSpace on 2015-04-22T22:08:50Z (GMT). No. of bitstreams: 1 DISSERTACAO_OTAVIO AUGUSTO PAIVA.pdf: 8701931 bytes, checksum: fa7ddfc8f71e05d7fe06a55c98faefc8 (MD5) Previous issue date: 2009-08-07 / Fundação de Amparo à Pesquisa do Estado do Amazonas / The experimental program of the present project was developed in order to evaluate the residue performance of ground plain glasses in cement based paste and mortar. Different conditions of grounding were used to generate a material with particles of the same order of magnitude of the cement particles. The ground glass residue (GGR) displayed physicalchemistry characteristics compatible to the ones of pozzolan, with relevance to the pozzolanic activity index (PAI). PAI equal to 104% was obtained, which is higher than that 75% -minimum value required by the Brazilian standard. The GGR was used in paste and mortar as a partial replacement of cement of 0%, 10%, 15% and 20% in mass, considering a waterbinder ratio of 0,4. The GGR behavior was evaluated through the X-Ray diffraction, thermal analysis, compressive strength, modulus of elasticity, porosity, water absorption, and alkaliaggregate reaction. The results did not indicate difference between the mechanical strength of the pastes with GGR and reference mixture after 28 days of curing. In mortars, the results of mechanical strength of the GGR mixtures were adequate from 7 days due to the filler and pozzolanic effects, mainly the 20% GGR mortar. In particular, the GGR provided increasing of compressive strength of 14% and 22% after 28 and 56 days of curing, respectively. / O programa experimental realizado no presente projeto foi desenvolvido de forma a avaliar o desempenho do resíduo de vidros planos moídos em pastas e argamassas a base de cimento Portland. Foram estudadas diferentes condições de moagem que possibilitassem a obtenção de um material com partículas da mesma ordem de gRandeza das partículas do cimento. O resíduo de vidro moído (RVM) apresentou características físico-químicas compatíveis às da pozolana, com destaque para o índice de atividade pozolânica. Obteve-se valor de 104%, empregando o cimento, que é superior a 75%, prescrito na norma brasileira. O RVM foi aplicado em pastas e argamassas como substituto parcial do cimento, para teores de 0%, 10%, 15%, e 20% em massa, para uma relação água-aglomerante de 0,4. O comportamento do RVM foi avaliado através de ensaios de difração de raios X, análise térmica, resistência à compressão, porosimetria, absorção, permeabilidade, módulo de elasticidade e reação álcaliagregado. Os resultados indicaram que as resistências mecânicas das pastas com RVM alcançaram o valor da resistência de referência a partir dos 28 dias. Nas argamassas foram obtidos resultados satisfatórios de resistência mecânica a partir dos 7 dias, iniciado pelo efeito de preenchimento e, posteriormente, pelo efeito pozolânico que superou os resultados de referência após os 28 dias, principalmente para o teor de 20%. Particularmente, o RVM aumentou a resistência à compressão em 14 e 22% após os 28 e 56 dias de cura, respectivamente.

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. / Cement paste is widely used in repositories for radioactive wastes, acting as structural and immobilization material. However, its use as backfill material in boreholes for sealed sources requires a longer service life of this material. The assessment of the cement paste behavior in long term is needed to improve the confidence that the material will perform as required during the service life of the facility. This research evaluated the changes in cement paste induced by degradation parameters. Portland cement paste specimens (cps) were submitted to accelerated degradation tests and the damage effects was evaluated by mechanical strength, variation of sample mass and volume, leaching/penetration of ions, XRD, TGA and SEM. It was observed that cps hydration was benefited by immersion (in distilled water or salt solution) and high temperatures, resulting in a higher strength. Dry storage, however, influenced the hydration process and maintained strength lower. Time of treatment and irradiation were not able to alter mineralogy and durability of cement paste.

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-05-04T18:22:01Z No. of bitstreams: 1 2012 - Adeval Alexandre Cavalcante Neto.pdf: 1289324 bytes, checksum: 75f78b3c067018946d5e3819dd1fb795 (MD5) / Made available in DSpace on 2017-05-04T18:22:01Z (GMT). No. of bitstreams: 1 2012 - Adeval Alexandre Cavalcante Neto.pdf: 1289324 bytes, checksum: 75f78b3c067018946d5e3819dd1fb795 (MD5) Previous issue date: 2012-06-25 / CAPES / The pasta is a food that is part of the table of the Brazilian people, possessing a high level of acceptability in all social classes. Because it is basically made up mostly of wheat flour is considered an energy food. Thus, it is vitally important that research be developed with alternative raw materials to replace partially the flour in the formulation of this mass and add the product better nutritional quality and / or sensory impairment. In this context an interesting alternative is the babassu mesocarp flour (Orbignya sp.). The objective of this research was the development of technology for the production of pasta mixed with the partial replacement of wheat flour (TF) by babassu mesocarp flour (BSF), seeking its nutritional enrichment and providing an alternative feed the population of Maranh?o. Four formulations of fresh noodles type have been developed, with the following composition: control (100% wheat flour), 90% flour + 10% flour mesocarp babassu, 85% flour + 15% of flour mesocarp babassu, 80% wheat flour + 20% babassu mesocarp flour. Were evaluated the physical, chemical and physico-chemical properties of flour and pasta, as well as microbiological and sensorial these. The data were processed by standard deviation, variance analysis and means compared by Tukey test (affective) and Dunnett's test (discriminative). The results of the chemical composition of flour mesocarp showed that this raw material has higher protein content than wheat flour, besides being rich in food fiber. The masses mixed with 10%, 15% and 20% of FMB, compared to controls, had increased the protein value of 28.85%, 41.60% and 51.68% and the fiber content was found to be 4.12 %, 5.28% and 6.51% respectively. Microbiological analyzes performed on the bodies testified that the products were hygienic and sanitary conditions. The addition of FMB to mass reduced the solids loss during cooking. Sensory evaluation showed an index of acceptability over 72% to pasta with 10% of FMB and 77.11% for the 15% mass of FMB, showing a good potential for use according to the literature and compared with the control were most appreciated by the judges. The pasta had a higher composite nutritional potential than the traditional mass and can be used as an alternative nutritional and income for the communities who live on the extraction of the babassu palm, using a piece of fruit that is usually neglected. / O macarr?o ? um alimento que faz parte da mesa do povo brasileiro, possuindo alto ?ndice de aceitabilidade em todas as classes sociais. Por ser constitu?do basicamente em sua maioria por farinha de trigo ? considerado um alimento energ?tico. Assim, ? de fundamental import?ncia que sejam desenvolvidas pesquisas com mat?rias primas alternativas que substituam parcialmente a farinha de trigo na formula??o dessa massa e que acrescentem ao produto melhor qualidade nutricional e/ou sensorial. Nesse contexto uma alternativa interessante, encontra-se na farinha de mesocarpo do baba?u (Orbignya sp.). O objetivo da pesquisa foi o desenvolvimento de tecnologia para a produ??o de massa aliment?cia mista com a substitui??o parcial da farinha de trigo (FT) pela farinha de mesocarpo de baba?u (FMB), visando seu enriquecimento nutricional e disponibilizando uma alternativa alimentar a popula??o maranhense. Quatro formula??es de massa fresca tipo talharim foram desenvolvidas, com as seguintes composi??es: controle (100% farinha de trigo); 90% farinha de trigo + 10% farinha de mesocarpo de baba?u; 85% farinha de trigo + 15% farinha de mesocarpo de baba?u; 80% farinha de trigo + 20% farinha de mesocarpo de baba?u. Foram avaliadas as caracter?sticas f?sicas, qu?micas e f?sico-qu?micas das farinhas e das massas aliment?cias, bem como as an?lises microbiol?gicas e sensorial destas. Os dados obtidos foram tratados por desvio padr?o, an?lise de vari?ncia e as m?dias comparadas pelo teste de Tukey (teste afetivo) e Dunnett (teste discriminativo). Os resultados da composi??o centesimal da farinha de mesocarpo mostraram que esta mat?ria prima possui maior teor prot?ico que a farinha de trigo, al?m de ser rica em fibra alimentar. As massas mistas com 10%, 15% e 20% de FMB, quando comparadas a controle, tiveram acr?scimo no valor prot?ico de 28,85%; 41,60% e 51,68% e quanto ao teor de fibras encontrado foi de 4,12%; 5,28% e 6,51%, respectivamente. As an?lises microbiol?gicas realizadas nas massas atestaram que os produtos apresentaram condi??es higi?nico-sanit?rias satisfat?rias. A adi??o de FMB ?s massas reduziu consideravelmente a perda de s?lidos durante o cozimento. A an?lise sensorial demonstrou um ?ndice de aceitabilidade acima de 72% para a massa com 10% de FMB e 77,11% para a massa com 15% de FMB, apresentando um bom potencial para consumo de acordo com a literatura e quando comparadas com a controle foram mais apreciadas pelos provadores. As massas aliment?cias mistas apresentaram um maior potencial nutritivo do que a massa tradicional e podem ser utilizadas como mais uma alternativa nutricional e de renda para as comunidades que vivem do extrativismo do coco baba?u, utilizando uma parte do fruto que normalmente ? desprezada.

O Brasil é o terceiro maior produtor de massas, com um volume de negócios anual de mais de um milhão de toneladas. Macarrão é uma fonte de energia, baixo custo, fácil de fazer, pode ser consumido em todas as estações, agrada a todos, apresenta variações de forma e cor que torna este produto tão popular. O objetivo do estudo foi o de avaliar a viabilidade de produção de um macarrão enriquecido a partir do bagaço obtido da extração de óleo de linhaça e estudar os efeitos da radiação gama no mesmo. Foram produzidas sete formulações de macarrão, sendo que duas foram irradiadas com 20kGy (20 e 40% de adição de farinha de bagaço de linhaça), duas foram produzidas com farinha do bagaço de linhaça irradiada a 10kGy nas proporções de 20 e 40%, duas não receberam nenhuma dose (nas proporções de 20 e 40%) e uma formulação de controle. As irradiações foram realizadas no irradiador multipropósito de Co60 do Instituto de Pesquisas Energéticas e Nucleares - IPEN/SP. As seguintes análises foram realizadas: determinação da umidade, acidez, pH, extrato etéreo, cinzas, proteína, fibra, textura, aderência e testes de cozimento, no Laboratório de Radiobiologia e Ambiente Centro de Energia Nuclear na Agricultura CENA/USP e na ESALQ em Piracicaba e as análises microbiológicas foram realizadas no Laboratório de Fungos Toxigênicos e Micotoxinas da USP/SP. Os valores da umidade e da acidez obtidos para os diferentes tipos de macarrão mostraram alta eficiência na secagem. As formulações M80:20, M80:20FT e M60:40 apresentaram também uma alta qualidade em relação ao aumento de massa e perda de sólidos solúveis segundo os parâmetros de Hummel. Houve também um aumento na quantidade de fibras ficando valor calórico reduzido. / Brazil is the third largest producer of pasta, with an annual turnover of more than one million tons. Pasta is a power source, low cost, convenient to make, can be eaten in all seasons, appeals to everyone, presents variations of shape and color which makes this product so popular. The aim of the study was to evaluate the feasibility of producing an enriched pasta using bagasse obtained from flaxseed oil extraction and study the effects of gamma radiation on the same. Seven preparations of noodles were produced, two of which were irradiated with 20kGy (20 and 40% of crushed flaxseed meal), two were produced with flour from crushed flaxseed irradiated to 10 kGy at the proportions of 20 and 40%, two did not receive a dose (proportions of 20 and 40%) and a control formulation. The irradiations were performed in the multipurpose irradiator of the Institute of Energy and Nuclear Research IPEN. The following analyzes were performed: determination of moisture, acidity, pH, ether extract, ash, protein, fiber, texture and cooking test, at the Laboratory of Radiobiology and Environmental Center for Nuclear Energy in Agriculture - CENA / USP. The values of moisture and acidity obtained for the different types of noodles showed high efficiency in drying. The formulations M80:20, M80:20FT e M60:40 also showed high quality in relation to the increase in the amount in mass and loss of soluble solids according to Hummel parameters. There was also an increase in the amount of fibers being reduced caloric values.

We conduct a comprehensive and systematic study of the Fermi-Pasta-Ulam (FPU) model using both equilibrium and non-equilibrium molecular dynamics simulations, with the aim being to explain the cause of the anomalous energy-transport behaviour in the model. In the equilibrium scenario, our motivation stems from the lack of a complete understanding of the effects of initial conditions on the energy dissipation among Fourier modes. We also critically reconsider the ????probes' that had been widely used to quantitatively describe the types of energy sharing in a system, and then decide on a preferred choice to be used in our equilibrium study. We establish, from strong numerical evidence, that there exists a critical energy density of approximately 0:1, above which the energy dissipation among the modes becomes independent of initial conditions and system parameters, and that the full equipartition of mode energy is never attained in the FPU model. We report, for the first time, the violation of particle positions in the FPU model at high energies, where the particles are found to pass through one another. In the non-equilibrium scenario, we critically review the Nos???Se-Hoover algorithm thermostatting method largely used by other works, and identify its weaknesses. We also review some other alternative methods and decide on the most appropriate one to be implemented throughout our work. We confirm the divergence of the thermal conductivity of the FPU model as the chain length increases, and that kfpu [symbol] No.41, in agreement with other works. Our study further shows that there exists an upper limit of the anharmonicity in the FPU model, and that any attempt to increase the strength of this anharmonicity will not succeed. We also introduce elastic collisions into the original FPU model and find that the Modified model (FPUC) still exhibits anomalous thermal conductivity. We conclude that a one-dimensional FPU-type model with ????only' nearest-neighbour interaction, regardless of being soft or hard, does not exhibit a finite thermal conductivity as the system size increases, due to the non-chaotic nature of its microscopic dynamics, the origin of which we are unable to account for. Finally, we briefly outline possible research directions.

There are about 40 durum wheat varieties registered in Turkey. Around 10 varieties are being commonly cultivated. Amanos 97, &Ccedil / esit 1252, Ege 88, Firat 93, Fuatbey 2000, Burgos, Kiziltan 91, Sari&ccedil / anak 98, Svevo and Zenith durum wheat varieties were used in this study. Semolina and pasta have been produced in an industrial plant under constant process conditions from these varieties. In general, pasta quality is determined by three main factors, the raw materials, the production recipe and the production process. In this study, the production recipe and the production process were fixed and only durum wheat varieties were variable. So, the effects coming from the production recipe and the production process on pasta quality were eliminated. Physical, chemical and sensory properties of these pasta were determined and the effect of different durum wheat varieties on pasta quality has been investigated to give a clear idea to the Turkish pasta industry about the most commonly grown durum wheat varieties in Turkey, hoping that Turkish pasta in domestic and international Markets will continue to grow with the help of clear understanding about the quality characteristics of the durum wheat they are using. v The important criteria of acceptability of pasta products is its cooking quality and cooking quality of pasta products is of importance to consumers and also to wheat producers, breeders and manufacturers. The pasta samples produced from Svevo, Zenith and Firat 93 varieties got the higher scores than others in pasta cooking quality while those produced from Sari&ccedil / anak 98, &Ccedil / esit 1252, Kiziltan 91, and Fuatbey 2000 durum wheat were evaluated as relatively low. The main reasons of cooking quality differences can be interpreted as a result of the difference in protein quantity and quality of the varieties. The bright yellow color of pasta products, rather than cooking behavior taste, is reported to be one of the most important considerations in assessing durum wheat quality. In this study, the pasta samples produced from Svevo, Zenith and Burgos varieties got the higher scores than others in pasta color (yellowness) while that produced from Firat 93 had the lowest yellow color. The main reasons of yellow color differences can be interpreted as a result of the differences in carotenoid pigments, lipoxygenase and peroxidase enzymes contents of the varieties.

Whole grain is associated with rougher texture and off-flavours which has decreased consumer acceptance. Pasta drying is also critical during production because of influence on texture and quality. The effects of drying type and whole grain content on physicochemical and qualitative properties of pasta were investigated. Increasing whole grain content lowered paste viscosity and increased cooking loss while low temperature drying improved quality. The impact of these effects on pasta texture and flavour was further explored. While bitterness, branniness, and surface roughness positively correlated with whole grain content, drying type only affected firmness. Phenolic content, headspace, and textural analysis corroborated this data. Change in pasta flavour upon addition of sodium-reduced cheese sauce was also examined. Sodium not only enhances flavour of dishes, it also suppresses bitterness. While flavours were uniquely affected upon sauce addition, sodium content did not affect bitterness. Headspace analysis using SIFT-MS showed volatile concentration to reduce, likely caused by a barrier created from the sauce. / MITACS Accelerate, Kraft Mississauga Mill

We conduct a comprehensive and systematic study of the Fermi-Pasta-Ulam (FPU) model using both equilibrium and non-equilibrium molecular dynamics simulations, with the aim being to explain the cause of the anomalous energy-transport behaviour in the model. In the equilibrium scenario, our motivation stems from the lack of a complete understanding of the effects of initial conditions on the energy dissipation among Fourier modes. We also critically reconsider the ????probes' that had been widely used to quantitatively describe the types of energy sharing in a system, and then decide on a preferred choice to be used in our equilibrium study. We establish, from strong numerical evidence, that there exists a critical energy density of approximately 0:1, above which the energy dissipation among the modes becomes independent of initial conditions and system parameters, and that the full equipartition of mode energy is never attained in the FPU model. We report, for the first time, the violation of particle positions in the FPU model at high energies, where the particles are found to pass through one another. In the non-equilibrium scenario, we critically review the Nos???Se-Hoover algorithm thermostatting method largely used by other works, and identify its weaknesses. We also review some other alternative methods and decide on the most appropriate one to be implemented throughout our work. We confirm the divergence of the thermal conductivity of the FPU model as the chain length increases, and that kfpu [symbol] No.41, in agreement with other works. Our study further shows that there exists an upper limit of the anharmonicity in the FPU model, and that any attempt to increase the strength of this anharmonicity will not succeed. We also introduce elastic collisions into the original FPU model and find that the Modified model (FPUC) still exhibits anomalous thermal conductivity. We conclude that a one-dimensional FPU-type model with ????only' nearest-neighbour interaction, regardless of being soft or hard, does not exhibit a finite thermal conductivity as the system size increases, due to the non-chaotic nature of its microscopic dynamics, the origin of which we are unable to account for. Finally, we briefly outline possible research directions.