In the present work, an investigation of the fatigue life benefits emerging from fillet weld geometries optimization has been carried out. At first, an introduction to ageing mechanisms, corrosion and especially fatigue, acting on operating marine structures has been made. Residual stresses at weld toes, stress modes, and types, geometrical factors (weld angle, toe radius, leg length), welding techniques selected, post-welding treatment and plate‟s material are some of the principal factors affecting the fatigue life of a fillet weld joint. Especially, the accuracy of various approaches in fatigue life estimation of specific geometries under pre-set types and levels of stress is studied. It is evident so far that even the notch stress concept is the most accurate method based on S-N curves, the Fracture Mechanics approach can offer more accurate solutions of a crack development through the material. Towards this, a literature review on crack evolution aspects in welded and non-welded plates under bending and tension was performed; substantial parameters were determined and finally implemented in the LEFM model which was used for the simulation purposes of Chapter 6. As far as the crack aspect ratio evolution is concerned, an extensive reference is available in literature since many researchers have investigated its contribution to the determination of geometrical paths, commonly known as “Preferred Propagation Paths”. Their significance is related with our ability to determine accurate SIF solutions leading to precise fatigue life estimations. A typical fillet weld joint 2-D model has been developed in CAE Abaqus software and a Finite Element Analysis of subject T-profile has been carried out. Through this analysis, the fillet weld angle, the weld leg length, the weld toe curvature radio ρ and the carrying load plate thickness are examined for their impacts on the maximum surface stress. Finally, a number of stress mitigating measures are proposed and their effects are analyzed. Undoubtedly, the notch stress concept today is gradually gaining more and more acceptance among other fatigue analysis practices, hence the need for an estimation of the actual surface stresses along fillet weld toes, has become imperative. Towards this, different 2-D geometries are tested against stress concentration factors developed at weld toes, which are calculated on the basis of maximum in-plane principal stresses over nominal stresses in mode I pure bending and pure tension respectively. Moreover, validation with corresponding results from literature is provided. Finally, three different concepts for reducing the maximum surface stresses are presented. The first one proposes grinding of the weld toe area and formulation of an artificial U-notch or a part- circular profile. The second one applies to non-penetrating welds and assumes the existence of a root gap of a specific geometry which is related to the fatigue life and stress concentration factor of the fillet weld joint. Last but not least, the relatively recent concept of the variable radius notch is discussed, even though it is applicable mostly to notched bodies, not weld joints. Afterwards, a Linear Elastic Fracture Mechanics analysis of reference 2D fillet weld model is demonstrated. A number of geometrical parameters considered at previous stage for their impact on surface Stress Concentration levels at the weld toe region, have been correlated to fatigue life benefits in terms of increased number of stress cycles till failure. An extensive analysis of 9 different T-butt weld joint geometries has been provided in order to investigate how positively a possible SCF reduction can affect the fatigue life of a weld joint. Essential geometric variations (weld angle, length, toe radius, root slot) were considered in the 2D model. All calculated benefits both in pure bending and pure tension cases have been reported accordingly. Based on a linear interpolation of the points scatter (SCF, N-cycles) both in banding and tension, it was observed that a surface stress mitigation of 1% could lead to 1,33 up to 2,5% fatigue life benefit in the range of SCF=2 – 2,5. It is evident so far that the geometrical optimization of a weld joint in respect of notch stress mitigation can be a powerful tool both in shipbuilding and maintenance practice in the future. However, technically wise their application may incur high initial costs of improved tools of welding and post welding treatment and robots even though it would consist a cost effective solution in a medium/long term basis. Finally, the above process is followed by a reliability analysis of the most critical geometrical parameters affecting the fatigue life of a fillet weld joint. Reliability assessment results concerning medium, high and low cycle fatigue are provided and a comparative analysis of each factor‟s impact on fatigue life has been carried out.

Orientador: Luiz Augusto do Amaral / Banca: Naiá Carla Marchi de Rezende Lago / Banca: Oswaldo Durival Rossi Junior / Resumo: 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 / Abstract: 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 / Mestre

Submitted by Marilene Donadel (marilene.donadel@unioeste.br) on 2018-04-20T19:26:59Z No. of bitstreams: 1 Nalva_Fritzen_2015.pdf: 1186463 bytes, checksum: bb35877d759f48f8281dbc14e226c99b (MD5) / Made available in DSpace on 2018-04-20T19:26:59Z (GMT). No. of bitstreams: 1 Nalva_Fritzen_2015.pdf: 1186463 bytes, checksum: bb35877d759f48f8281dbc14e226c99b (MD5) Previous issue date: 2015-02-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The objective of this study was to analyze the productive performance, the physical and chemical composition and the cost benefit of tilapia production (Oreochromis niloticus) in cages, in three different weight classes (500, 700 and 900g) termination. 24.000 fish were used, with initial weight of 150 ± 5,4 g for analysis of cost of production, over thirty cages of 6 m3 of useful volume. A sample of five fish for cage was harvested for yield performance, including 10% of those steaks were used for chemical analysis. To survey costs and profitability, we used the Operating Cost (Effective and Total), Depreciation, Total Cost and Profit. At the end it was observed that the smaller fish (500g) showed a smaller amount of lipids (1,76%) and visceral (3,69%) and a higher content of ash (1,40%) in the fillet. The best fillet yield and main trunk was found in larger fish (900g), 32,48% and 50,82% respectively. The profitability of production, the average fish (700g) stood out (19,77%). / O objetivo neste trabalho foi analisar o desempenho produtivo, a composição físico-química e o custo benefício da produção de tilápias do Nilo (Oreochromis niloticus) em tanques-rede, em três diferentes classes de peso (500, 700 e 900g) de terminação. Foram utilizados 24.000 peixes, com peso inicial de 150±5,4g, para análise de custo da produção, distribuídos em trinta tanques-rede de 6m3 de volume útil. Uma amostra de cinco peixes por tanque foi abatida para o desempenho produtivo, dos quais 10% dos filés obtidos foram utilizados para análise bromatológica. Para o levantamento dos custos e rentabilidade, utilizou-se o Custo Operacional (Efetivo e Total), Depreciação, Custo Total e Lucro. Ao final observou-se que os peixes menores (500g) apresentaram menor quantidade de lipídeos (1,76%) e gordura visceral (3,69%) e, maior teor de matéria mineral (1,40%) no filé. O melhor rendimento de filé e tronco limpo foi encontrado nos peixes maiores (900g), 32,48% e 50,82% respectivamente. Quanto a lucratividade da produção, os peixes médios (700g) se destacaram (19,77%).

Submitted by Fabielle Cheuczuk (fabielle.cheuczuk@unioeste.br) on 2018-05-07T13:28:45Z No. of bitstreams: 2 Dissertaçao Andreia final.pdf: 1005086 bytes, checksum: b352c63e848b1a7a5cfd8e1f42b47aca (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-05-07T13:28:45Z (GMT). No. of bitstreams: 2 Dissertaçao Andreia final.pdf: 1005086 bytes, checksum: b352c63e848b1a7a5cfd8e1f42b47aca (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-02-23 / The quality of school feeding influences directly the schoolchildren’s quality of life. Some animal origin products provided to the school feeding in the municipal network of Francisco Beltrão – PR come from the family agriculture, this research aimed to evaluate the quality of samples of meat products and of fish supplied, microbiological analyzes of beef (piece and ground), pork, chicken, bovine liver and fillet of tilapia, and the facilities, equipment, utensils and manipulators, with the verification of the items that evaluate the agro-industries hygienic-sanitary conditions of producing these products. The perception of the good manufacturing practices of the agribusiness manipulators was carried out by the application of a questionnaire. The results showed that some samples of pork, bovine meat, bovine liver and fillet of tilapia are not suitable for consumption, because they present Salmonella spp. in 25g. In the pork, bovine and fish agroindustries, facilities, equipments and utensils presented contamination by aerobic mesophiles and enterobacteria, ranging from 4 CFU to> 300 CFU and 9.6x10UFC to> 300 CFU, respectively. Regarding the checklist, the cattle and fish agro-industries accounted for 85% of the items and the pork agroindustry accounted for 50% of the items. However, food handlers are aware of good manufacturing practices, they know how contamination occurs, but they do not seem to take the necessary care, which was verified in the hand swab evaluation whose counts indicated readings of up to> 300 CFU / hand. / A qualidade da alimentação escolar influencia diretamente a qualidade de vida dos escolares. Considerando que alguns produtos de origem animal fornecidos para a alimenta- ção escolar da rede municipal de Francisco Beltrão – PR são provenientes da agricultura familiar, esta pesquisa teve o objetivo de avaliar a qualidade de amostras dos produtos cárneos e do pescado fornecidos pelas agroindústrias familiares, por meio de análises microbiológicas das carnes bovina (pedaço e moída), suína, frango, fígado bovino e do filé de tilápia, e das instalações, equipamentos, utensílios e dos manipuladores, ainda com a verificação dos itens que avaliam as condições higiênico-sanitárias das agroindústrias produtoras destes produtos. A percepção das boas práticas de fabricação, dos manipuladores das agroindústrias foi realizada com a aplicação de um questionário. Os resultados obtidos demonstraram que algumas amostras de carne suína, bovina em pedaço, fígado bovino e filé de tilápia encontram-se impróprias para consumo, pois apresentaram presença de Salmonella spp. em 25g. Nas agroindústrias de suínos, bovinos e pescado, as instalações, equipamentos e utensílios apresentaram contaminação por mesófilos aeróbios e enterobactérias, que variaram de 4 UFC a > 300 UFC e 9,6x10UFC a >300 UFC, respectivamente. Com relação à lista de verificação, as agroindústrias de bovinos e de peixe atenderam à 85% dos itens e a agroindústria de suínos a 50% dos itens. Já os manipuladores de alimentos têm noção das boas práticas de fabricação, conhecem como ocorre a contaminação, mas não parecem adotar os cuidados necessários, o que foi verificado na avaliação de swab de mãos, cujas contagens apontaram leituras de até > 300 UFC/ mão.

Made available in DSpace on 2017-07-10T17:48:15Z (GMT). No. of bitstreams: 1 Paulo_Roberto_Poggere.pdf: 1235913 bytes, checksum: d755c1fed9bce078365b85e719b7f835 (MD5) Previous issue date: 2009-03-06 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The present study had as objective evaluates the performance, chemical composition, morphometrics reasons and yield of the fillet of three tilápia lineages: Supreme (SUP), Chitralada (CHIT) and Bouaké (BOU). The used experimental design was randomized entirely, composed by 3 treatments and 6 repetitions. 18 concrete tanks were used, where 30 fingerlings were stocked, with medium initial weight of 2,03 ± 0,25 g, 1,65 ± 0,06 g and 1,57 ± 0,11 g for SUP, CHIT and BOU respectively, totaling 540 fingerlings, being 180 fingerlings for each lineage. The fish were fed 3 times a day, with commercial diet of the type crumbed with 42% of CP for the alevinagem phase, and extruded with the levels of 36% CP for the growth phase and 32% CP for the fattening phase. The amount of diet was adjusted through the medium weight and temperature of the water. The biometry were accomplished biweekly, being captured 30% of the copies of each tank. The zootechnical indexes and the length data along the time were appraised through ANCOVA. The filet income was evaluated through ANOVA. Already the morphometrics reasons, were analyzed starting from MANOVA. For the zootechnical indexes, there were significant effects of the lineages on the Tax of Growth (TG), Earnings of Biomass (EB) and Final (FW) Weight. For TG and FW, CHIT differed significantly of the other ones, presenting largest TG and FW (2,543 g/day and 307 g), while SUP and BOU didn't differ significantly amongst themselves. In EB, CHIT and SUP they presented the best result (7.207,40 and 6.898,15 g, respectively), differing significantly of BOU. With relationship the morphometrics reasons, there was significant difference among the lineages. Already in the yield of the fillet without skin (YF), there were not significant effects among the lineages. The chemical composition of the fillet presented significant differences for ethereal (EE) extract and crude protein (CP) protein. For EE, the three lineages differed statistically amongst themselves, and BOU presented the largest value with 1,42%, following by SUP and CHIT. For CP, SUP (20,79%) and BOU (20,73%) they only differed of CHIT. For the growth in length, CHIT presented the largest value of L¥, with 27,39 cm, following by SUP (27,16 cm) and BOU (26,67 cm). Regarding the value of k (growth tax in length), SUP presented the largest value (0,4456), following by CHIT with 0,4349 and BOU (0,4141). In the growth in weight, CHIT obtained the largest value for W¥ with 534,15 g, following by SUP with 516,20 g and BOU 454,76 g. However, SUP was superior in the coefficient of growth alométrico (q) with 3,2442, being respectively the values of 3,2206 and 3,1773 for CHIT and BOU. It was verified that CHIT obtained the best results for TG, FW, EB and tenor of EE in the filet in comparison with SUP and BOU, besides presenting morphometrics reasons that provide a rounder format of his body being the lineage more adapted for cultivation in those imposed conditions and weight strip / O presente estudo teve como objetivo avaliar o desempenho produtivo, composição química, razões morfométricas e rendimento do filé de três linhagens de tilápia: Supreme (SUP), Chitralada (CHIT) e Bouaké (BOU). O delineamento experimental utilizado foi inteiramente casualizado, composto por três tratamentos e seis repetições. Foram utilizados 18 tanques de concreto, onde foram estocados 30 alevinos, com peso inicial médio de 2,03 ± 0,25 g, 1,65 ± 0,06 g e 1,57 ± 0,11 g para SUP, CHIT e BOU respectivamente, totalizando 540 alevinos, sendo 180 alevinos para cada linhagem. Os peixes foram alimentados três vezes ao dia, com ração comercial do tipo farelada com 42% de PB para a fase de alevinagem, e extrusada com os níveis de 36% PB para a fase de crescimento e 32% PB para a fase de engorda. A quantidade de ração foi ajustada através do peso médio e temperatura da água. As biometrias foram realizadas quinzenalmente, sendo capturados 30% dos exemplares de cada tanque. Os índices zootécnicos e os dados de comprimento ao longo do tempo foram avaliados através da ANCOVA, o rendimento de filé foi avaliado através da ANOVA e as razões morfométricas, foram analisadas a partir de MANOVA. Para os índices zootécnicos, houveram efeitos significativos das linhagens sobre a Taxa de Crescimento (TC), Ganho em Biomassa (GB) e Peso Final (PF). Para a TC e PF, a CHIT diferiu significativamente das outras, apresentando a maior TC e PF (2,543 g/dia e 307 g), enquanto a SUP e BOU não diferiram significativamente entre si. No GB, a CHIT e SUP apresentaram o melhor resultado (7.207,40 e 6.898,15 g, respectivamente), diferindo significativamente da BOU. Com relação as razões morfométricas, houve diferença significativa entre as linhagens. Já no rendimento de filé sem pele (RF), não houveram efeitos significativos entre as linhagens. A composição química do filé apresentou diferenças significativas para extrato etéreo (EE) e proteína bruta (PB). Para o EE, as três linhagens diferiram estatisticamente entre si, sendo que a BOU apresentou o maior valor com 1,42%, seguida da SUP e CHIT. Para PB, a SUP (20,79%) e BOU (20,73%) somente diferiram da CHIT. Para o crescimento em comprimento, a CHIT apresentou o maior valor de L¥, com 27,39 cm, seguida da SUP (27,16 cm) e BOU (26,67 cm). Com relação ao valor de k (taxa de crescimento em comprimento), a SUP apresentou o maior valor (0,4456), seguida da CHIT com 0,4349 e BOU (0,4141). No crescimento em peso, a CHIT obteve o maior valor para W¥ com 534,15 g, seguida da SUP com 516,20 g e BOU 454,76 g. Entretanto, a SUP foi superior no coeficiente de crescimento alométrico (q) com 3,2442, sendo os valores de 3,2206 e 3,1773 para CHIT e BOU respectivamente. Verificou-se que CHIT obteve os melhores resultados para TC, PF, GB e teor de EE no filé em comparação SUP e BOU; além de apresentar razões morfométricas que proporcionam um formato mais arredondado do seu corpo, sendo a linhagem mais adaptada para cultivo nessas condições impostas e faixa de peso

Welding is a key process for heavy steel structures, but it is also a weak link in the structure since fatigue fractures in welds are a common cause of failure. This thesis proposes several changes in order to improve the fatigue properties in acost effective way, enabling reduced weight and reduced cost of welded structures. The main idea is to adapt the weld requirements and welding procedures to the load conditions of the weld. This approach ensures that the main focus in the welding process is the critical characteristics of the welds fatigue life properties. The fatigue life critical properties are most often related to the geometrical factors of the weld such as the radius at the weld toe or the penetration in the root. The thesis describes a holistic view of the subject and covers fatigue, weld quality, weld requirements and welding procedures. It becomes evident that the traditional way of working without a direct connection to fatigue is not the best. With an adaptation to the load conditions and fatigue, it is possible to enhance the fatigue life and reduce the welding cost. The main challenge is to connect the welding process, weld requirements and fatigue life properties. It is needed for an optimised welding process of heavy structures subjected to fatigue and toget a predictable fatigue life. Welds optimised for enhanced fatigue life properties are not necessary accepted according to the requirements in a current standard. Several welding procedures are proposed for improving the fatigue life properties of the weld, which indicate a high potential for enhanced fatigue lifeof fillet welds. The idea is to replace the "standard" fillet weld with three different weld types: (i) Welds with deep penetration, (ii) Welds with large weld toe radius and (iii) Welds produced with low cost. Together with customised requirements and reduced over-welding there is a vast potential for reduced weight, reduced cost and increased productivity.The main contribution of this thesis work is the cross-functional studies including design, analysis, production and quality control. This gives a framework for improvements supporting reduced cost and reduced weight of VIII welded structures without reducing the fatigue strength. Many shortcomings have been highlighted to change the welding from a state where welds are done in a way as they "always" have, by tradition, to a more contemporary situation where weld requirements and welding procedures are actively chosen to match the load conditions of the weld. This result in requirements and welding procedures which actually are connected to the fatigue properties as defined by the loading conditions, and where auditors with high probability can say that an accepted weld actually is better than a rejected weld.

This thesis work is concerned with effect of material grade on fatigue strength of welded joints. Fatigue strength evaluation of welded joints in as welded and post weld treated condition was carried out with effective notch method. Results of peak stress method have also been compared with those of effective notch method for as welded joints. In addition, using the results of effective notch method, the effect of important weld and global geometry factors on notch stress concentration factor has been studied with 2-level design of experiment and a mathematical relation among stress concentration factor and the geometric factors has been proposed. Overall, thickness of the base plate and toe radius is found to be the most important factors determining fatigue strength of the joint. Welding induced residual stresses have also been predicted using 2D and 3D FEM analysis to see their effect on fatigue strength of the joints. Also, transversal residual stresses were measured using X-ray diffraction method to assess the accuracy of predicted results. Based on simulation results, effect of geometric factors on maximum value of transversal residual stress was also investigated.

No description available.

No description available.

The objective of the present diploma thesis was to verify the influence of monosex populations in African catfish (Clarias gariepinus) fishfarming on growth rate, growth heterogeneity, feed conversion ratio, yield and product quality in the operating conditions of a small fish farm with a recirculating aquaculture system. In six tanks with a volume of 0,3 m-3, 60 individuals with an average unit weight of 614 ? 135 g, all-male, all-female and mixed- sex (in 2 repeats each) were deployed. The fish were fed with feed in the usual and registered feed doses 4 times a day. At the end of the experiment, 119 days average fish weight reached 1445 ? 911 g. The composition of the populations was found to have a statistically significant effect on the food conversion ratio, gonadosomal index, and fillet yield. Statistically significant differences were not found in specific growth ratio (SGR), growth heterogeneity, or muscle composition (fat and protein content). The yield of fillets without skin reached only 40.74 ? 1.81% for all-female group. An economically advantageous alternative to a mixed -sex groupe with a sex ratio of 1: 1 was a all-male fishfarning groupe where the yield of skinless fillets was 46.99 ? 1.12%. Food conversions were also more favorable for all-male groups (FCR = 1.08 ? 0.08 and 1.04 ? 0.12) compared to all-female (FCR = 1.18 ? 0.21 and 1.25 ? 0.19 ). The fat content of the muscle at the end of the experiment varied between 5.10-10.53% for each group without proven dependence on the type of the group, the protein content showed only minimal differences, varied between 15.18 and 16.46%, dry mass contained muscle from 24.23 to 27.95% without proven dependence on the type of occupancy. Significant economic impact has the composition of groups when evaluating the yield of fillets without skin as the final product.