Análise do efeito de filetes de adesivo na resistência estática de juntas adesivas tubulares

A procura de otimização na construção de equipamentos e estruturas tem vindo a gerar o surgimento de novos materiais, assim como novos processos de construção e de ligação. As juntas adesivas tubulares (JAT) são uma solução e possibilitam a construção de estruturas de forma mais simples, económica, leve e até resistente. Assim surge a necessidade de estudar várias variáveis que melhorem o desempenho e construção das JAT. Esta dissertação visa estudar a influência da aplicação de filetes de adesivo, com diferentes ângulos (), nas extremidades de ligação das JAT. São também considerados dois comprimentos de sobreposição (L0) de diferentes (L0=20 mm e L0=40 mm). De forma a abranger uma ampla gama de adesivos foram considerados três adesivos de características diferentes: Araldite® AV138, que se trata de um adesivo epóxido frágil, Araldite® 2015, que também é um adesivo epóxido, mas apresenta uma ductilidade moderada, e SikaForce® 7752, que se trata de um adesivo de poliuretano dúctil. Para o estudo paramétrico numérico foram utilizados modelos de dano coesivo (MDC). Inicialmente, esta técnica foi validada com resultados experimentais obtidos em trabalhos anteriores. O trabalho numérico consistiu numa análise elástica de tensões da camada de adesivo e previsão de resistência, por MDC, em função dos parâmetros geométricos e materiais referidos. Foi também realizado um estudo sobre a variável dano. Este estudo permitiu analisar a influência das alterações geométricas consoante os diferentes tipos de adesivos, possibilitando a verificação de qual a geometria que melhor se enquadra a cada tipo de adesivo. A conjugação de parâmetros que apresentou uma resistência maior, residiu no Araldite® AV138, com =7,5° e L0=40 mm.The search for optimization in the construction of equipment and structures has been generating the appearance of new materials, as well as new construction and joining processes. Tubular adhesive joints (TAJ) are a solution and make it possible to build structures in a simpler, more economical, light and even resistant manner. Thus, there is a need to study several variables that improve TAJ performance and construction. This thesis aims to study the influence of the application of adhesive fillets, with different angles, at the TAJ bonding ends. Two different overlap lengths (L0) are also considered (L0=20 mm and L0=40 mm). In order to cover a wide range of adhesives, three adhesives of different characteristics were considered: Araldite® AV138, which is a brittle epoxy adhesive, Araldite® 2015, which is also an epoxy adhesive, but has a moderate ductility and SikaForce® 7752, which it is a ductile polyurethane adhesive. For the numerical parametric study, cohesive zone models (CZM) were used. Initially, this technique was validated with experimental results obtained in previous works. The numerical work consisted of an elastic stress analysis in the adhesive layer and strength prediction, by CZM, according to the referred geometric and material parameters. A study was also conducted on the variable damage. This study made it possible to analyse the influence of geometric changes depending on the different types of adhesives, enabling the verification of which geometry best fits each type of adhesive. The combination of parameters that showed a higher resistance, resided in Araldite® AV138, with =7,5° e L0=40 mm

Sistema tracionador de intervenção compreendendo um umbilical

PETROBRASUniversidade Federal do Rio Grande do SulEngenhariaInformáticaDepositad

Sistema tracionador de intervenção compreendendo um umbilical

PETROBRASUniversidade Federal do Rio Grande do SulEngenhariaInformáticaDepositad

Brazilian Flora 2020: Leveraging the power of a collaborative scientific network

International audienceThe shortage of reliable primary taxonomic data limits the description of biological taxa and the understanding of biodiversity patterns and processes, complicating biogeographical, ecological, and evolutionary studies. This deficit creates a significant taxonomic impediment to biodiversity research and conservation planning. The taxonomic impediment and the biodiversity crisis are widely recognized, highlighting the urgent need for reliable taxonomic data. Over the past decade, numerous countries worldwide have devoted considerable effort to Target 1 of the Global Strategy for Plant Conservation (GSPC), which called for the preparation of a working list of all known plant species by 2010 and an online world Flora by 2020. Brazil is a megadiverse country, home to more of the world's known plant species than any other country. Despite that, Flora Brasiliensis, concluded in 1906, was the last comprehensive treatment of the Brazilian flora. The lack of accurate estimates of the number of species of algae, fungi, and plants occurring in Brazil contributes to the prevailing taxonomic impediment and delays progress towards the GSPC targets. Over the past 12 years, a legion of taxonomists motivated to meet Target 1 of the GSPC, worked together to gather and integrate knowledge on the algal, plant, and fungal diversity of Brazil. Overall, a team of about 980 taxonomists joined efforts in a highly collaborative project that used cybertaxonomy to prepare an updated Flora of Brazil, showing the power of scientific collaboration to reach ambitious goals. This paper presents an overview of the Brazilian Flora 2020 and provides taxonomic and spatial updates on the algae, fungi, and plants found in one of the world's most biodiverse countries. We further identify collection gaps and summarize future goals that extend beyond 2020. Our results show that Brazil is home to 46,975 native species of algae, fungi, and plants, of which 19,669 are endemic to the country. The data compiled to date suggests that the Atlantic Rainforest might be the most diverse Brazilian domain for all plant groups except gymnosperms, which are most diverse in the Amazon. However, scientific knowledge of Brazilian diversity is still unequally distributed, with the Atlantic Rainforest and the Cerrado being the most intensively sampled and studied biomes in the country. In times of “scientific reductionism”, with botanical and mycological sciences suffering pervasive depreciation in recent decades, the first online Flora of Brazil 2020 significantly enhanced the quality and quantity of taxonomic data available for algae, fungi, and plants from Brazil. This project also made all the information freely available online, providing a firm foundation for future research and for the management, conservation, and sustainable use of the Brazilian funga and flora

Management of coronary disease in patients with advanced kidney disease

BACKGROUND Clinical trials that have assessed the effect of revascularization in patients with stable coronary disease have routinely excluded those with advanced chronic kidney disease. METHODS We randomly assigned 777 patients with advanced kidney disease and moderate or severe ischemia on stress testing to be treated with an initial invasive strategy consisting of coronary angiography and revascularization (if appropriate) added to medical therapy or an initial conservative strategy consisting of medical therapy alone and angiography reserved for those in whom medical therapy had failed. The primary outcome was a composite of death or nonfatal myocardial infarction. A key secondary outcome was a composite of death, nonfatal myocardial infarction, or hospitalization for unstable angina, heart failure, or resuscitated cardiac arrest. RESULTS At a median follow-up of 2.2 years, a primary outcome event had occurred in 123 patients in the invasive-strategy group and in 129 patients in the conservative-strategy group (estimated 3-year event rate, 36.4% vs. 36.7%; adjusted hazard ratio, 1.01; 95% confidence interval [CI], 0.79 to 1.29; P=0.95). Results for the key secondary outcome were similar (38.5% vs. 39.7%; hazard ratio, 1.01; 95% CI, 0.79 to 1.29). The invasive strategy was associated with a higher incidence of stroke than the conservative strategy (hazard ratio, 3.76; 95% CI, 1.52 to 9.32; P=0.004) and with a higher incidence of death or initiation of dialysis (hazard ratio, 1.48; 95% CI, 1.04 to 2.11; P=0.03). CONCLUSIONS Among patients with stable coronary disease, advanced chronic kidney disease, and moderate or severe ischemia, we did not find evidence that an initial invasive strategy, as compared with an initial conservative strategy, reduced the risk of death or nonfatal myocardial infarction

Health status after invasive or conservative care in coronary and advanced kidney disease

BACKGROUND In the ISCHEMIA-CKD trial, the primary analysis showed no significant difference in the risk of death or myocardial infarction with initial angiography and revascularization plus guideline-based medical therapy (invasive strategy) as compared with guideline-based medical therapy alone (conservative strategy) in participants with stable ischemic heart disease, moderate or severe ischemia, and advanced chronic kidney disease (an estimated glomerular filtration rate of <30 ml per minute per 1.73 m2 or receipt of dialysis). A secondary objective of the trial was to assess angina-related health status. METHODS We assessed health status with the Seattle Angina Questionnaire (SAQ) before randomization and at 1.5, 3, and 6 months and every 6 months thereafter. The primary outcome of this analysis was the SAQ Summary score (ranging from 0 to 100, with higher scores indicating less frequent angina and better function and quality of life). Mixed-effects cumulative probability models within a Bayesian framework were used to estimate the treatment effect with the invasive strategy. RESULTS Health status was assessed in 705 of 777 participants. Nearly half the participants (49%) had had no angina during the month before randomization. At 3 months, the estimated mean difference between the invasive-strategy group and the conservative-strategy group in the SAQ Summary score was 2.1 points (95% credible interval, 120.4 to 4.6), a result that favored the invasive strategy. The mean difference in score at 3 months was largest among participants with daily or weekly angina at baseline (10.1 points; 95% credible interval, 0.0 to 19.9), smaller among those with monthly angina at baseline (2.2 points; 95% credible interval, 122.0 to 6.2), and nearly absent among those without angina at baseline (0.6 points; 95% credible interval, 121.9 to 3.3). By 6 months, the between-group difference in the overall trial population was attenuated (0.5 points; 95% credible interval, 122.2 to 3.4). CONCLUSIONS Participants with stable ischemic heart disease, moderate or severe ischemia, and advanced chronic kidney disease did not have substantial or sustained benefits with regard to angina-related health status with an initially invasive strategy as compared with a conservative strategy

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field