Made available in DSpace on 2014-11-10T11:09:48Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-11-29Bitstream added on 2014-11-10T11:58:02Z : No. of bitstreams: 1 000792656.pdf: 3661871 bytes, checksum: f2c3e3e3d7a967eea0fbfe7baa565706 (MD5) / Os tubos de concreto com diâmetros superiores a 400 mm são utilizados em bueiros, travessias, drenagem pluvial, esgoto sanitário e canalizações de abastecimento; já os resíduos de borracha de pneu estão sendo aplicados com diversas finalidades, como por exemplo: combustível alternativo para as indústrias de cimento, na fabricação de solados de sapato, em borrachas de vedação, dutos pluviais, pisos para quadras poliesportivas, pisos industriais, asfalto-borracha, tapetes para automóveis e diversos tipos de concreto. Os resíduos de borracha de pneu quando adicionadas ao concreto podem melhorar algumas propriedades, tais como: impermeabilidade, flexibilidade, resistência à abrasão e resistência à corrosão. Em outro contexto, a incorporação destes resíduos no concreto surge como uma possibilidade para se atenuar impactos ambientais, ainda mais sabendo que ele é gerado em abundância durante o processo de recauchutagem. Observa-se, no entanto, que a inclusão desse resíduo pode provocar uma diminuição da resistência à compressão axial e do módulo de deformação longitudinal. Esta pesquisa tem por objetivo analisar o comportamento mecânico de protótipo de tubos de concreto feitos com diferentes teores de adições de resíduos de borracha de pneu. tais como: 10 kg/m³, 15 kg/m³, 20 kg/m³, 25 kg/m³ e 30 kg/m³, com base na norma NBR 8890 (ABNT, 2007). Os tubos de concreto possuem 600 mm de diâmetro nominal e 1,5 m de comprimento, sendo destinados aos sistemas de drenagem de águas pluviais. Os tubos de concreto foram submetidos, em escala real, ao ensaio de resistência à compressão diametral e de absorção de água, cujas amostras foram retiradas dos tubos após o ensaio de compressão diametral. Os resultados obtidos no ensaio de compressão diametral foram satisfatórios, todos os traços superaram o valor mínimo da norma, mas os resíduos de borracha de pneu não se comportaram como fibras. O teor de 15 kg ... / The concrete pipes with diameters greater than 400 mm are used in culverts, crossings, rainwater drainage, sanitary sewer and plumbing supply. The tire rubber residues are being applied to various purposes such as: alternative fuel for the cement industry, in the manufacture of shoe soles in rubber seals, rainwater pipes, flooring for sports courts, industrial floors, asphalt-rubber mats for automobiles and various types of concrete. The tire rubber residue, when added to concrete, may improve some properties such as impermeability, flexibility, abrasion resistance and corrosion resistance. In another context, incorporation in the concrete of these residues appears as a possibility to mitigate environmental impacts, especially knowing that it is generated abundantly during the retreading process. It is noted, however, that the inclusion of this residue may lead to a decrease in compressive strength and modulus of elasticity. Based on standard NBR 8890 (ABNT, 2007), this research aims to analyze the mechanical behavior of prototypes of concrete pipes made with different contents of additions of tire rubber residue, such as: 10 kg/m³, 15 kg/m³, 20 kg/m³, 25 kg/m³ and 30 kg/m³. The concrete pipes that were studied had nominal diameter of 600 mm and length of 1.5 m, being intended for drainage systems of rainwater. The concrete pipes in real scale were submitted to the test of diametral compression strength and, after their ruptures, to the water absorption test, which samples were collected from the broken pieces. The results obtained by the diametral compression test were satisfactory since all pipes made with the mixtures exceeded the minimum value of the brazilian standard, but the tire rubber residue did not behave as a fiber. The content of 15 kg of tire rubber residue per cubic meter of concrete was the one who had the best performance. The addition of tire rubber residue had not changed the characteristic of concrete related to ...

Orientador: José Luiz Pinheiro Melges / Co-orientador: Jorge Luís Akasaki / Banca: Mauro Mitsuuchi Tashima / Banca: João Henrique da Silva Rêgo / Resumo: Os tubos de concreto com diâmetros superiores a 400 mm são utilizados em bueiros, travessias, drenagem pluvial, esgoto sanitário e canalizações de abastecimento; já os resíduos de borracha de pneu estão sendo aplicados com diversas finalidades, como por exemplo: combustível alternativo para as indústrias de cimento, na fabricação de solados de sapato, em borrachas de vedação, dutos pluviais, pisos para quadras poliesportivas, pisos industriais, asfalto-borracha, tapetes para automóveis e diversos tipos de concreto. Os resíduos de borracha de pneu quando adicionadas ao concreto podem melhorar algumas propriedades, tais como: impermeabilidade, flexibilidade, resistência à abrasão e resistência à corrosão. Em outro contexto, a incorporação destes resíduos no concreto surge como uma possibilidade para se atenuar impactos ambientais, ainda mais sabendo que ele é gerado em abundância durante o processo de recauchutagem. Observa-se, no entanto, que a inclusão desse resíduo pode provocar uma diminuição da resistência à compressão axial e do módulo de deformação longitudinal. Esta pesquisa tem por objetivo analisar o comportamento mecânico de protótipo de tubos de concreto feitos com diferentes teores de adições de resíduos de borracha de pneu. tais como: 10 kg/m³, 15 kg/m³, 20 kg/m³, 25 kg/m³ e 30 kg/m³, com base na norma NBR 8890 (ABNT, 2007). Os tubos de concreto possuem 600 mm de diâmetro nominal e 1,5 m de comprimento, sendo destinados aos sistemas de drenagem de águas pluviais. Os tubos de concreto foram submetidos, em escala real, ao ensaio de resistência à compressão diametral e de absorção de água, cujas amostras foram retiradas dos tubos após o ensaio de compressão diametral. Os resultados obtidos no ensaio de compressão diametral foram satisfatórios, todos os traços superaram o valor mínimo da norma, mas os resíduos de borracha de pneu não se comportaram como fibras. O teor de 15 kg ... / Abstract: The concrete pipes with diameters greater than 400 mm are used in culverts, crossings, rainwater drainage, sanitary sewer and plumbing supply. The tire rubber residues are being applied to various purposes such as: alternative fuel for the cement industry, in the manufacture of shoe soles in rubber seals, rainwater pipes, flooring for sports courts, industrial floors, asphalt-rubber mats for automobiles and various types of concrete. The tire rubber residue, when added to concrete, may improve some properties such as impermeability, flexibility, abrasion resistance and corrosion resistance. In another context, incorporation in the concrete of these residues appears as a possibility to mitigate environmental impacts, especially knowing that it is generated abundantly during the retreading process. It is noted, however, that the inclusion of this residue may lead to a decrease in compressive strength and modulus of elasticity. Based on standard NBR 8890 (ABNT, 2007), this research aims to analyze the mechanical behavior of prototypes of concrete pipes made with different contents of additions of tire rubber residue, such as: 10 kg/m³, 15 kg/m³, 20 kg/m³, 25 kg/m³ and 30 kg/m³. The concrete pipes that were studied had nominal diameter of 600 mm and length of 1.5 m, being intended for drainage systems of rainwater. The concrete pipes in real scale were submitted to the test of diametral compression strength and, after their ruptures, to the water absorption test, which samples were collected from the broken pieces. The results obtained by the diametral compression test were satisfactory since all pipes made with the mixtures exceeded the minimum value of the brazilian standard, but the tire rubber residue did not behave as a fiber. The content of 15 kg of tire rubber residue per cubic meter of concrete was the one who had the best performance. The addition of tire rubber residue had not changed the characteristic of concrete related to ... / Mestre

Orientador: Newton de Oliveira Pinto Junior / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil / Made available in DSpace on 2018-08-03T20:38:51Z (GMT). No. of bitstreams: 1 Ramos_MarceloFrancisco_M.pdf: 4157437 bytes, checksum: c4709e78995883db4ccd27990e329973 (MD5) Previous issue date: 2002 / Resumo: Neste trabalho são apresentados os resultados de um programa experimental desenvolvido para avaliar a resistência à compressão diametral de tubos de concreto reforçado com fibras de aço. Foram moldados tubos com diâmetro nominal de 600 mm em concretos de resistências médias à compressão, aos 28 dias de idade, de aproximadamente 50MPa. Os tubos foram divididos em seis séries, sendo 5 em concreto simples, 5 em concreto armado, 10 em concreto reforçado com fibras coladas em pentes (5 com teor de 20 kglm3 e 5 com teor de 30 kgl m3) e 10 em concreto reforçado com fibras soltas (5 com teor de 20 kglm3 e 5 com teor de 30 kgl m3). O objetivo é avaliar o comportamento desses tubos de concreto reforçado com fibras de aço, verificando seu desempenho comparativamente à tubos de concreto simples e de concreto armado, quando submetidos ao ensaio de compressão diametral. Foram também determinadas as resistências à compressão simples, à tração na compressão diametral, bem como a tenacidade à flexão dos concretos empregados na produção. Os ensaios realizados demonstraram um comportamento dúctil dos tubos de concreto reforçado com fibras de aço, demonstrando que a substituição das armaduras convencionais pelas fibras de aço é possível, mantendo a mesma capacidade de suporte, com ganhos significativos de durabilidade / Abstract: In this work will be presented the results of an experimental program developed to evaluate the diametrical compressive strenght of concrete pipes reinforced with fibers of steel. They were moulded pipes with nominal diameter of 600 mm in concretes of medium compressive strenght, to the 28 days of age, of approximately 50MPa. The pipes were divided in six series, being 5 in plain concrete, 5 in reinforced concrete, 10 in concrete reinforced with agglutinated fibers of steel in combs (5 with 20 kg/m3 and 5 with 30kg/m3) and 10 in concrete reinforced with looses fibers (5 with 20kg/m3 and 5 with 30kg/m3). The objective is to evaluate the behavior of those concrete pipes reinforced with fibers of steel, verifying its acting comparatively to pipes of plain concrete and of reinforced concrete, when submitted to the test of diametrical compressive. They were also determined the compressive strenght, to the traction in the compressive diametrical, as well as the flexural toughness to the concretes employees in the production. The accomplished rehearsals demonstrated a ductile behavior of the concrete tubes reinforced with fibers of steel, demonstrating that the substitution of the conventional armors for. the fibers of steel is possible, maintaining the same support capacity, with having won significant of durability / Mestrado / Edificações / Mestre em Engenharia Civil

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This thesis describes the design of two particular types of conventional distributed amplifiers and treats a proposed split-band amplifier. The method used for the conventional designs is an iterative synthesis process developed at Stanford University in 1952. The objective was to investigate the possibility of producing distributed amplifiers of superior performance. Only amplifiers with a flat amplitude response were considered since the calculating equipment available was inadequate for the computations involved in producing amplifiers with other types of response characteristics. Three designs of one form of conventional distributed amplifier were carried out. These were amplifiers with ladder networks for delay lines and with both delay lines identical except for a possible difference in impedance level. None of the three amplifiers had theoretical characteristics which justified an attempt to construct them. The other conventional amplifier was one employing ladder-like networks for the delay lines with each of the lines symmetrical about the mid-point of its length and with both lines identical except for a possible difference in impedance level. An attempt to design one of these amplifiers produced new information beyond that reported in the original work at Stanford University. Furthermore, when using the iterative technique to design this amplifier, there seemed to be reasonable doubt as to whether or not the process was always convergent. No definite opinion on the matter was formulated since it would have required that the calculations be continued through more cycles of iteration than could reasonably be carried out with the computing equipment at hand. Finally, a proposed split-band amplifier was investigated and its theoretical gain-bandwidth characteristics were compared with those of a conventional distributed amplifier. It showed a slight advantage, but this was far outweighed by certain serious inherent disadvantages and the project was discontinued. The investigation has shown that it is impractical to carry out the calculations involved in the iterative prodecure when using a hand calculator. Also, some doubt as to the general convergence of the iterative synthesis process has been raised. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

Several studies have proposed the fallopian tube epithelium as a site of origin of ovarian cancer. The discovery of precursor lesions in the fallopian tube in patients at risk for ovarian cancer supports a probable origin for high-grade serous ovarian carcinoma in this tissue. While the fallopian tube epithelium consists of three distinct cell types, the paired box protein 2 (PAX2) positive cells and potentially the CD44 positive stem-like cells are most relevant to ovarian cancer. Loss of PAX2 expression in the fallopian tube cells is considered to be an early event in epithelial transformation, but the specific role of PAX2 in this transition is unknown. The aim of this study was to define the role of PAX2 in oviductal epithelial cells (OVE) cells and in mouse ovarian surface epithelial cells (MOSE), and to understand its contribution to the formation of serous precursor lesions in the fallopian tubes. Herein, we studied the OVE response to transforming growth factor β (TGFβ, a cytokine found in follicular fluid) and provide evidence of its potential involvement in the regulation of stem cell-like behaviors that may contribute to formation of cancer-initiating cells. Treatment of primary cultures of OVE cells with TGFβ at concentrations found in ovulatory follicular fluid induced an epithelial-mesenchymal transition (EMT) with expected changes in proliferation, cell morphology and expression of SNAIL, Vimentin and E-cadherin. EMT was also associated with decreased expression of PAX2 and an increase in the fraction of cells expressing CD44. Pax2 knockdown in OVE cells and overexpression in ovarian epithelial cells confirmed that PAX2 inhibits CD44 expression and regulates the degree of epithelial differentiation of OVE cells. These results suggest that the loss of PAX2 seen in serous tubal intraepithelial carcinomas (STIC) leads to a shift to a more mesenchymal phenotype associated with stem-like features. Pax2 overexpression in MOSE cells also induced the formation of vascular channels both in vitro and in vivo, which indicate a possible contribution of PAX2 to ovarian cancer progression by increasing the vascular channels to supply nutrients to the tumor cells. Furthermore, since loss of PAX2 in STIC was found associated with P53 and BRCA1 mutations, OVE cells with mutations of the tumor suppressor genes Trp53 and Brca1 were studied. We found that loss of Trp53 with or without loss of Brca1 increased cell proliferation and colony formation in vitro. In addition, loss of Trp53 induced OVE cells to undergo EMT and induced the expression of stem cell–associated genes. We therefore suggest a potential contribution of stem cells in initiating the precursor lesions in the fallopian tubes in combination with tumor suppressor gene mutation.

Among semi-destructive methods of measuring residual stresses in elastic materials, the blind hole-drilling strain-gage method is one of the best because it is simple, economical and accurate. It is based on the measurement of strains disturbed by machining a small diameter shallow hole in the test piece. The strains measured in three known directions permit the determination of the direction and magnitude of principal stresses and subsequently of any stress in any direction. This thesis presents the investigation of residual stresses in the longitudinal direction of a welded fabricated steel tube of 22 inch diameter, relating to a series of holes drilled in one half of a circular section of the tube. An initial assumption, substantiated later, was the existence of a uniform field of residual stresses through the thickness of the tube. Several methods for determining calibration coefficients are documented. The values of longitudinal stresses once computed are presented in a smooth curve. A straight line approximation is reconnnended for use in further studies of the effects of residual stresses on failure loads.

Using data for the longitudinal residual stress distribution in welded steel tubes, curves describing these distributions are selected for study. Each of these curves are checked for static balance across the tube cross section. The curves that exhibit an imbalance are adjusted by a combination of a simplified model for each and the use of a computer program that is developed to calculate the resulting forces and moments on the cross section. The residual stress in the area of the tube wall opposite the longitudinal weld is found to be the most important in the adjustment to obtain exact equilibrium. The method of adjustment is rational and based on maintaining a smooth curve shape that matches the raw data the closest and producing a curve that is balanced within the accuracy limits required.