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Presented master thesis deals with computational modelling (simulation) of welding process. Its main goal is to determine the residual stresses and deformations arising after welding. SYSWELD and ANSYS are used for simulation, both based on the finite element method. Specifically, the processes of welding fillet and butt welds are solved. Results from both software are compared with each other and verified by experimental results.

Red fillet results in a profit loss for catfish processors and producers alike; however, neither the cause nor the abundance of red fillet has been studied extensively. Therefore, an assessment of red fillet in the catfish industry was conducted along with studies subjecting catfish to poor water quality and inoculation with Aeromonas sobria. Within every catfish harvest, 0.12% of fillets were rejected due to blotchy red coloration. Histology revealed congestion of erythrocytes indicating internal hemorrhaging, and A. sobria was isolated from 63% of all red fillets compared to 28% of acceptable fillets. Acute exposure to poor water quality did not produce red fillet in catfish despite high stress levels and mortality rates (22%). Inoculation with A. sobria did induce red fillet with similar coloration to red fillets obtained from catfish processors.

Made available in DSpace on 2014-06-11T19:22:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-04Bitstream added on 2014-06-13T20:09:26Z : No. of bitstreams: 1 gattijunior_p_me_jabo.pdf: 375413 bytes, checksum: 84c43699cec0d037bc0f63dba9fc7f0c (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O objetivo deste trabalho foi avaliar os riscos para a saúde pública apresentado por tilápias, produzidas em cativeiro, comercializadas em supermercados na região nordeste de São Paulo. Para tal, análises microbiológicas foram realizadas, em 40 amostras de tilápias in natura e em 50 filés de tilápias. No peixe in natura foi analisado a água de enxaguadura da pele e o trato gastrintestinal. Os números mais prováveis de coliformes totais e termotolerantes foram determinados assim como a contagem Staphylococcus coagulase positivo e a presença de Salmonella spp. de acordo com a American Public Health Association (APHA). Os resultados obtidos foram analisados utilizando valores logarítmicos e as médias comparadas pelo teste de Tukey, com nível de 5% de probabilidade. A pele foi o tecido com maior nível de contaminação em relação ao trato gastrintestinal e músculo de tilápia in natura. O número de amostras com presença de coliformes totais e termotolerantes na água de enxaguadura da pele foi, respectivamente, 72,5% e 60%, no trato gastrintestinal 25% e 12,5% e no músculo 17,5% e 5%. A carga bacteriana foi significativamente maior no filé em relação ao músculo. Em duas amostras de filé foram verificados Staphylococcus coagulase positivo, uma acima dos parâmetros microbiológicos estabelecidos pela Resolução RDC nº 12/2001 da ANVISA. Salmonella spp. não foi detectada em nenhuma amostra analisada. As amostras de peixes estavam em boas condições para consumo, com exceção de duas amostras de filé. Os filés apresentaram maior contaminação que o músculo da tilápia in natura. Indicadores de poluição fecal demonstraram que a pele foi o órgão com maior contaminação / The objective of this work was to evaluate the risks to public health of consumption of tilápia fish growed in captivity and commercialised in supermarkets in the Northwest region of São Paulo state. In order to accomplish with the objective the researcher undertook analysis in 40 samples of fresh tilápias and in 50 fillets of the fish. In the fresh fish it was also analysed the washing water of the skin and of the gastrointestinal tract. It were determined, in accordance to the American Public Health Association (APHA), the number of total and thermotolerant fecal coliforms as well as the number of coagulase-positive Staphylococcus and presence of the bacteria Salmonella spp. The results were analyzed using logarithmic values and means compared by Tukey test with 5% of probability. The skin was the tissue with higher levels of contamination comparing with the gastrointestinal tract and muscle of the fresh tilapia. The percentage of samples with total and thermotolerant fecal coliforms in the skin washing water was 72.5% and 60% respectively; 25% and 12.5% in the gastrointestinal tract and 17.5% and 5% in the muscles. Bacterial presence was significantly higher in fillets comparing to muscles. Moreover, it was noticed presence of coagulase-positive Staphylococcus in two samples of fillet; one of them showed levels above of the microbiological parameters established by the RDC resolution no. 12/2001 ANVISA. Additionally, it was not identified presence of Salmonella spp in any of the samples analyzed. Generally, the studied samples were in good condition for human consumption, except for two samples of fillets. Fillets presented higher levels of contamination comparing with muscles of the fresh tilapia. Fecal pollution indicators have proved that the skin was the organ with higher levels of contamination

El presente trabajo de investigación busca describir las dificultades que ha ocasionado el protocolo técnico de registro sanitario de importación de productos pesqueros y acuícolas congelados impuesto por la autoridad sanitaria competente del Perú respecto a la importación y comercialización del filete de tilapia congelado proveniente de un nuevo productor chino a partir de la experiencia de la empresa Umi Foods S.A.C., por lo tanto nuestro estudio se divide en cuatro (4) capítulos, los cuales son detallados a continuación. El primer capítulo se centra en el plan de investigación, por medio del cual planteamos la pregunta, el problema y los objetivos, tanto principales como específicos y la formulación de la hipótesis inicial de la investigación. El segundo capítulo da a conocer los antecedentes de la investigación, tanto nacionales como internacionales y el marco teórico del estudio, así como las restricciones para la importación y los requisitos para la comercialización del filete de tilapia congelado. El tercer capítulo se centra en la metodología de la investigación, donde detallamos el tipo, propósito, categorías, delimitación, diseño y tamaño de muestra de la investigación. Asimismo, en este capítulo desarrollamos las entrevistas de profundidad, las cuales serán de utilidad para el recojo de información. Finalmente, el cuarto capítulo se enfoca en el respectivo análisis y discusión de resultados de nuestra investigación para así encontrar los hallazgos y realizar tanto las conclusiones como las recomendaciones finales por medio del análisis de documentos y de la información obtenida mediante las entrevistas de profundidad desarrolladas en nuestro estudio. / The present research seeks to describe the difficulties caused by the technical protocol of import sanitary registration for frozen fishery and aquiculture products from the sanitary authority of Peru regarding the import and commercialization of frozen tilapia fillet that comes from a new Chinese producer and according to the experience of the company Umi Foods S.A.C., therefore our study is divided into four chapters that are detailed as below. The first chapter focuses on the planning research, which is about proposing the research question, the main and specific problems and objectives. In this chapter we also make known about the starting hypothesis of our working research. In the second chapter we present the national and international backgrounds and the theory framework of the research as well as the import restrictions and the commercialization requirements of the frozen tilapia fillet. The third chapter explains the methodology research, which we detail the type, purpose, categories, delimitation, design and sampling size of the research. Also, in this chapter we develop depth interviews that will be very useful for the research’s collecting information. Finally, the fourth chapter is about the respective analysis and discussion of the research´s results in order to get the findings of the study and make the final conclusions and recommendations according to the documents’ analysis and to the obtained information from held depth interviews in our research. / Tesis

In this study, effect of fillet rolling process on fatigue performance of a diesel engine crankshaft was investigated. Crankshafts from two different materials, were studied / ductile cast iron EN-GJS 800-2 and micro-alloyed steel 38MnVS6. Resonance bending fatigue tests were conducted with crankshaft samples. Test plan according to staircase test methodology was used. Statistical analyses were carried out with the test data by Maximum Likelihood Estimation method in order to calculate the fatigue limits and construct the S-N curves based on Random Fatigue Limit (RFL) and Modified Basquin models. Fatigue limit calculations were also conducted by Dixon-Mood method and by Maximum Likelihood Estimation methodology for Normal and Weibull distributions. Fillet rolling process was simulated by computer based analysis in order to calculate the compressive residual stress profile at the fillet region to shed more light on the mechanisms and effect of fillet rolling. Fatigue performances of crankshafts from two types of materials were evaluated both at unrolled and fillet rolled states. Effect of fillet rolling load on fatigue performance was also evaluated with steel crankshafts. It was found that ductile cast iron showed better performance under bending fatigue tests than the steel crankshaft both at the fillet rolled and unrolled conditions. On the other hand, fillet rolling process was found to be more effective on steel crankshaft than ductile cast iron crankshaft in terms of fatigue performance improvement. It was also seen that fatigue limit increases with the fillet rolling load up to a limit where surface quality is deteriorated. Residual stress analysis showed that a higher magnitude of residual stress can develop on steel crankshaft fillet region whereas the effective depth of the residual stress is higher on ductile cast iron crankshaft with the same rolling condition. Residual stress analysis of steel crankshafts rolled at different rolling conditions show that, peak residual stress increase with the increasing rolling load is not significantly high and main effect of increased rolling load is the increased effective depth of residual stresses. The MLE methodology used in statistical analysis of the test data was found to be effective for life regression and fatigue strength distributions analysis. RFL model has provided better life regression analysis and fatigue limit calculations than Modified Basquin model. Dixon-Mood method was found to be overestimating the fatigue limit.