Este trabalho objetivou o conhecimento do comportamento estrutural de um sistema solo-tubo plástico flexível de paredes estruturadas frente a cargas permanentes sobre a tubulação e carregamentos móveis, como os provenientes de tráfego de veículos. Para o estudo, foram construídas valas em verdadeira grandeza na Área de Pesquisas e Testes de Pavimentos DAER-RS/UFRGS em Porto Alegre, RS, onde se dispõe de um equipamento simulador de tráfego, utilizado para aplicação de cargas estáticas e cíclicas na superfície dos sistemas solo-tubo. As variáveis independentes controladas são o grau de compactação do material que envolve o tubo e altura do mesmo material sobre o tubo. As variáveis medidas são a deflexão do tubo sob carregamento do simulador e o deslocamento permanente causado pela carga de solo sobre o tubo. O controle de compactação do material de envolvimento do tubo foi realizado com três equipamentos diferentes e os resultados foram comparados. Os resultados de deflexão e deslocamento pemanente foram utilizados para cálculo dos valores de módulo de reação E' do maerial de envolvimento do tubo e foram comparados com os encontrados na literatura. Constatou-se o comportamento elástico dos tubos sob carregamento repetido, e no caso em que o tubo é instalado muito próximo da superfície, as deflexões no sistema são de tal magnitude que chegam a ser prejudiciais ao pavimento construído sobre a vala. Ficou comprovada a importância da cuidadosa compactação do material de envolvimento do tubo para o bom desempenho estrutural do sistema solo-tubo flexível. / This work aimed at the knowledge of the structural behavior of a ribbed flexible plastic buried pipe system undergoing permanent loads on the piping and mobile loads, as the ones deriving from the traffic of vehicles. For this study, full scale ditches were built at the DAER-RS/UFRGS Pavement Research and Test Area in Porto Alegre, RS, where there is a equipment for simulating traffic, used for applying both static and cyclic loads on the ditch surface. The controled independent variables are the involving material density and the height of this material on the pipe. The variables measured are the pipe deflection under simulator load and the permanent displacement caused by the soil load on the pipe. The compaction control of involving material was carried out with three different types of equipment and results were compared. The results for pemanent deflection and displacement were used to calculate the Modulus of Soil Reaction (E') values of the involving material and these were compared to the ones found in the literature. The pipe elastic behavior under repeated load was observed, and where the pipe is installed too close to the surface, the system deflections are of such magnitude that they affect the pavement built over the ditch. The careful compaction of the involving material proved to be of paramount importance to a good structural performance of the flexible buried pipe system.

Este trabalho objetivou o conhecimento do comportamento estrutural de um sistema solo-tubo plástico flexível de paredes estruturadas frente a cargas permanentes sobre a tubulação e carregamentos móveis, como os provenientes de tráfego de veículos. Para o estudo, foram construídas valas em verdadeira grandeza na Área de Pesquisas e Testes de Pavimentos DAER-RS/UFRGS em Porto Alegre, RS, onde se dispõe de um equipamento simulador de tráfego, utilizado para aplicação de cargas estáticas e cíclicas na superfície dos sistemas solo-tubo. As variáveis independentes controladas são o grau de compactação do material que envolve o tubo e altura do mesmo material sobre o tubo. As variáveis medidas são a deflexão do tubo sob carregamento do simulador e o deslocamento permanente causado pela carga de solo sobre o tubo. O controle de compactação do material de envolvimento do tubo foi realizado com três equipamentos diferentes e os resultados foram comparados. Os resultados de deflexão e deslocamento pemanente foram utilizados para cálculo dos valores de módulo de reação E' do maerial de envolvimento do tubo e foram comparados com os encontrados na literatura. Constatou-se o comportamento elástico dos tubos sob carregamento repetido, e no caso em que o tubo é instalado muito próximo da superfície, as deflexões no sistema são de tal magnitude que chegam a ser prejudiciais ao pavimento construído sobre a vala. Ficou comprovada a importância da cuidadosa compactação do material de envolvimento do tubo para o bom desempenho estrutural do sistema solo-tubo flexível. / This work aimed at the knowledge of the structural behavior of a ribbed flexible plastic buried pipe system undergoing permanent loads on the piping and mobile loads, as the ones deriving from the traffic of vehicles. For this study, full scale ditches were built at the DAER-RS/UFRGS Pavement Research and Test Area in Porto Alegre, RS, where there is a equipment for simulating traffic, used for applying both static and cyclic loads on the ditch surface. The controled independent variables are the involving material density and the height of this material on the pipe. The variables measured are the pipe deflection under simulator load and the permanent displacement caused by the soil load on the pipe. The compaction control of involving material was carried out with three different types of equipment and results were compared. The results for pemanent deflection and displacement were used to calculate the Modulus of Soil Reaction (E') values of the involving material and these were compared to the ones found in the literature. The pipe elastic behavior under repeated load was observed, and where the pipe is installed too close to the surface, the system deflections are of such magnitude that they affect the pavement built over the ditch. The careful compaction of the involving material proved to be of paramount importance to a good structural performance of the flexible buried pipe system.

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<p>The rotator cuff is a group of four muscles and tendons in the shoulder that function to lift and rotate the arm. Rotator cuff tendon tears are increasingly common: more than 545,000 rotator cuff surgeries occur annually in the US. However, treatment is often complicated by disorganized collagen matrix formed via fibrosis and results in high re-tear rates. Tendon tissue engineering seeks to solve the problem using biomaterials to promote neo-tendon formation to augment repair or regenerate tendon. However, while current biomaterials provide the opportunity to improve tendon healing, they frequently still exhibit fibrosis in preclinical studies. Therefore, a critical need exists to understand the mechanisms of aligned collagen formation when designing biomaterials for tendon tissue engineering. Matrix architecture and transient receptor potential cation channel subfamily V member 4 (TRPV4) regulate aligned collagen formation during tenogenesis in vitro, but the mechanism remains to be determined. Recently, TRPV4 stimulation was found to induce nuclear localization and activation of transcriptional co-activators Yes-associated protein (YAP). YAP expression is upregulated during tendon development, a process characterized by aligned collagen formation, and in response to physiological mechanical stimulation, suggesting it could play an important role in tendon. The objective of this work is to improve tissue engineering strategies and progress toward making a device that regenerate tendon after injury. Aim 1 incorporates tendon-derived matrix into synthetic polymer scaffolds to add biological signaling cues to induce tenogenesis. Aim 2 uses a 2D photolithography system (microphotopatterning) to optimize architectural and structural cues to promote stem cell differentiation toward tenogenic, chondrogenic, and osteogenic lineages. Aim 3 investigates dynamic tensile loading protocols to promote collagen matrix synthesis and improve engineered tendon mechanical function. Aim 4 investigates the role of TRPV4 and YAP in collagen alignment during engineered tendon development.</p>