924 resultados para Calculation tool in reliability


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The ever-increasing robustness and reliability of flow-simulation methods have consolidated CFD as a major tool in virtually all branches of fluid mechanics. Traditionally, those methods have played a crucial role in the analysis of flow physics. In more recent years, though, the subject has broadened considerably, with the development of optimization and inverse design applications. Since then, the search for efficient ways to evaluate flow-sensitivity gradients has received the attention of numerous researchers. In this scenario, the adjoint method has emerged as, quite possibly, the most powerful tool for the job, which heightens the need for a clear understanding of its conceptual basis. Yet, some of its underlying aspects are still subject to debate in the literature, despite all the research that has been carried out on the method. Such is the case with the adjoint boundary and internal conditions, in particular. The present work aims to shed more light on that topic, with emphasis on the need for an internal shock condition. By following the path of previous authors, the quasi-1D Euler problem is used as a vehicle to explore those concepts. The results clearly indicate that the behavior of the adjoint solution through a shock wave ultimately depends upon the nature of the objective functional.

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Background: Obstetric ultrasound has come to play a significant role in obstetrics since its introduction in clinical care. Today, most pregnant women in the developed world are exposed to obstetric ultrasound examinations, and there is no doubt that the advantages of obstetric ultrasound technique have led to improvements in pregnancy outcomes. However, at the same time, the increasing use has also raised many ethical challenges. This study aimed to explore obstetricians' experiences of the significance of obstetric ultrasound for clinical management of complicated pregnancy and their perceptions of expectant parents' experiences. Methods: A qualitative study was undertaken in November 2012 as part of the CROss-Country Ultrasound Study (CROCUS). Semi-structured individual interviews were held with 14 obstetricians working at two large hospitals in Victoria, Australia. Transcribed data underwent qualitative content analysis. Results: An overall theme emerged during the analyses, 'Obstetric ultrasound - a third eye', reflecting the significance and meaning of ultrasound in pregnancy, and the importance of the additional information that ultrasound offers clinicians managing the surveillance of a pregnant woman and her fetus. This theme was built on four categories: I:'Everyday-tool' for pregnancy surveillance, II: Significance for managing complicated pregnancy, III: Differing perspectives on obstetric ultrasound, and IV: Counselling as a balancing act. In summary, the obstetricians viewed obstetric ultrasound as an invaluable tool in their everyday practice. More importantly however, the findings emphasise some of the clinical dilemmas that occur due to its use: the obstetricians' and expectant parents' differing perspectives and expectations of obstetric ultrasound examinations, the challenges of uncertain ultrasound findings, and how this information was conveyed and balanced by obstetricians in counselling expectant parents. Conclusions: This study highlights a range of previously rarely acknowledged clinical dilemmas that obstetricians face in relation to the use of obstetric ultrasound. Despite being a tool of considerable significance in the surveillance of pregnancy, there are limitations and uncertainties that arise with its use that make counselling expectant parents challenging. Research is needed which further investigates the effects and experiences of the continuing worldwide rapid technical advances in surveillance of pregnancies.

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As a highly urbanized and flood prone region, Flanders has experienced multiple floods causing significant damage in the past. In response to the floods of 1998 and 2002 the Flemish Environment Agency, responsible for managing 1 400 km of unnavigable rivers, started setting up a real time flood forecasting system in 2003. Currently the system covers almost 2 000 km of unnavigable rivers, for which flood forecasts are accessible online (www.waterinfo.be). The forecasting system comprises more than 1 000 hydrologic and 50 hydrodynamic models which are supplied with radar rainfall, rainfall forecasts and on-site observations. Forecasts for the next 2 days are generated hourly, while 10 day forecasts are generated twice a day. Additionally, twice daily simulations based on percentile rainfall forecasts (from EPS predictions) result in uncertainty bands for the latter. Subsequent flood forecasts use the most recent rainfall predictions and observed parameters at any time while uncertainty on the longer-term is taken into account. The flood forecasting system produces high resolution dynamic flood maps and graphs at about 200 river gauges and more than 3 000 forecast points. A customized emergency response system generates phone calls and text messages to a team of hydrologists initiating a pro-active response to prevent upcoming flood damage. The flood forecasting system of the Flemish Environment Agency is constantly evolving and has proven to be an indispensable tool in flood crisis management. This was clearly the case during the November 2010 floods, when the agency issued a press release 2 days in advance allowing water managers, emergency services and civilians to take measures.

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Existing distributed hydrologic models are complex and computationally demanding for using as a rapid-forecasting policy-decision tool, or even as a class-room educational tool. In addition, platform dependence, specific input/output data structures and non-dynamic data-interaction with pluggable software components inside the existing proprietary frameworks make these models restrictive only to the specialized user groups. RWater is a web-based hydrologic analysis and modeling framework that utilizes the commonly used R software within the HUBzero cyber infrastructure of Purdue University. RWater is designed as an integrated framework for distributed hydrologic simulation, along with subsequent parameter optimization and visualization schemes. RWater provides platform independent web-based interface, flexible data integration capacity, grid-based simulations, and user-extensibility. RWater uses RStudio to simulate hydrologic processes on raster based data obtained through conventional GIS pre-processing. The program integrates Shuffled Complex Evolution (SCE) algorithm for parameter optimization. Moreover, RWater enables users to produce different descriptive statistics and visualization of the outputs at different temporal resolutions. The applicability of RWater will be demonstrated by application on two watersheds in Indiana for multiple rainfall events.

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In this paper the architecture of an experimental multiparadigmatic programming environment is sketched, showing how its parts combine together with application modules in order to perform the integration of program modules written in different programming languages and paradigms. Adaptive automata are special self-modifying formal state machines used as a design and implementation tool in the representation of complex systems. Adaptive automata have been proven to have the same formal power as Turing Machines. Therefore, at least in theory, arbitrarily complex systems may be modeled with adaptive automata. The present work briefly introduces such formal tool and presents case studies showing how to use them in two very different situations: the first one, in the name management module of a multi-paradigmatic and multi-language programming environment, and the second one, in an application program implementing an adaptive automaton that accepts a context-sensitive language.

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Esta dissertação apresenta uma metodologia de retroalimentação do ciclo de desenvolvimento de produtos, com ênfase na fase de projeto, a partir de dados obtidos em estudos de confiabilidade. A metodologia é proposta com base no escopo da norma QS-9000, norma esta que vem sendo utilizada por fornecedores e sub-fornecedores da indústria automobilística no mundo inteiro. Um estudo de caso permitiu que a metodologia fosse implementada em uma empresa certificada na norma. São aplicadas retroalimentações em ferramentas como Desdobramento da Função Qualidade (QFD), Análise dos Modos e Efeitos de Falha de Produto (DFMEA) e de Processo (PFMEA). Os resultados obtidos demonstraram que a metodologia de retroalimentação proposta é uma ferramenta útil na maturação de um produto, através da utilização dos dados de falhas em campo, bem como no momento do desenvolvimento de um produto novo, que irá suceder o atual, através da utilização da voz do cliente e dos dados de falha em campo de forma ordenada.

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A melhoria nos sistemas de manutenção é cada dia mais importante para o aprimoramento das atividades de uma empresa, tanto na área de produção como em outros setores. Pode-se afirmar, então, que uma boa sistemática de manutenção colabora para que a empresa cumpra suas funções em relação à confiabilidade, flexibilidade, rapidez, qualidade, mantendo custos competitivos. O presente trabalho analisa, de acordo com um prisma teórico e prático, um esforço de implantação da Manutenção Produtiva Total (TPM-“Total Productive Maintenance”). Ele tem como principal objetivo descrever e discutir a implantação da TPM em uma empresa fabricante de massas e biscoitos. Em um primeiro momento, a implantação aconteceu em uma linha piloto. O ponto de partida foi a apresentação da TPM com seus passos para implantação e pilares que sustentam esta ferramenta. Na seqüência, descreve-se como aconteceu a implantação desta sistemática na linha piloto da empresa, discutindo as dificuldades, vantagens e desvantagens percebidas. As conclusões do trabalho apontam para resultados percebidos na linha piloto, onde a implantação ocorreu, possibilitando a percepção de melhorias para a empresa e para seus colaboradores. Foram observadas melhorias tanto no que concerne à manutenção dos equipamentos quanto ao envolvimento das pessoas em todo o processo.

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O sucesso de um programa de perda de peso para animais de estimação depende da colaboração do proprietário. A adesão deste é fundamental para a correta instituição do manejo alimentar do paciente. Este trabalho teve por objetivo comparar a efetividade de um programa de perda de peso em dois grupos de cães, um mantido sob condições experimentais e outro com seus proprietários. Empregou-se a mesma ração hipocalórica para todos os animais. A quantidade fornecida foi restrita a 60% da necessidade energética de manutenção estimada para o peso corporal meta, definido como o peso autal reduzido em 15%. Os animais foram acompanhados durante 90 dias. Por meio de um questionário padronizado, estudou-se a percepção dos proprietários quanto à obesidade e seu tratamento. Verificou-se que o protocolo e a dieta empregados foram eficazes. Os animais controle apresentaram uma perda de peso média de 1,39% por semana. Os cães de proprietário perderam, em média, 0,75% do peso vivo por semana, resultado estatisticamente menor (P<0,05), o que sugere uma indisponibilidade dos mesmos em cumprir rigorosamente o tratamento. Mesmo com esta perda de peso modesta, foi perceptível a satisfação dos proprietários com os resultados obtidos. O uso de questionários demonstrou ser uma ferramenta importante na investigação das causas e no acompanhamento do tratamento da obesidade canina.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The oil industry`s need to produce with maximum efficiency, not to mention the safety and the environment aspects, encourages the optimization of processes. It makes them look for a level of excellence in acquisition of equipment, ensuring the quality without prejudice security of facilities and peoples. Knowing the reliability of equipment and that this stands for a system is fundamental to the production strategy to seeks the maximum return on investment. The reliability analysis techniques have been increasingly applied in the industry as strategy for predicting failures likelihood ensuring the integrity of processes. Some reliability theories underlie the decisions to use stochastic calculations to estimate equipment failure. This dissertation proposes two techniques associating qualitative (through expertise opinion) and quantitative data (European North Sea oil companies fault database, Ored) applied on centrifugal pump to water injection system for secondary oil recovery on two scenarios. The data were processed in reliability commercial software. As a result of hybridization, it was possible to determine the pump life cycle and what impact on production if it fails. The technique guides the best maintenance policy - important tool for strategic decisions on asset management.

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The analysis of mitochondrial DNA (mtDNA) is a useful tool in forensic cases when sample contents too little or degraded nuclear DNA to genotype by autosomal short tandem repeat (STR) loci, but it is especially useful when the only forensic evidence is a hair shaft. Several authors have related differences in mtDNA from different tissues within the same individual, with high frequency of heteroplasmic variants in hair, as also in some other tissues. Is still a matter of debate how the differences influence the interpretation forensic protocols. One difference between two samples supposed to be originated from the same individual are related to an inconclusive result, but depending on the tissue and the position of the difference it should have a different interpretation, based on mutation-rate heterogeneity of mtDNA. In order to investigate it differences in the mtDNA control region from hair hafts and blood in our population, sequences from the hypervariable regions 1 and 2 (HV1 and HV2) from 100 Brazilian unrelated individuals were compared. The frequency of point heteroplasmy observed in hair was 10.5% by sequencing. Our study confirms the results related by other authors that concluded that small differences within tissues should be interpreted with caution especially when analyzing hair samples. (C) 2007 Elsevier B.V.. All rights reserved.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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This article presents a cooling system for cutting tool in turning based in a toolholder with cooling fluid flowing inside its body being that this fluid must necessarily be able to phase change due to heat generated from machining processes. In this way, the fluid evaporates just under the cutting tool allowing a heat transfer more efficient than if were used a fluid without phase change once the latent heat of evaporation is beneficial for removal heat. Following, the cooling fluid evaporated passes through a condenser located out of the toolholder where it is condensated and returns to the toolholder again and a new cycle is started. In this study, the R-123, a hydrochlorofluorocarbon (HCFC) fluid, was selected for the turning of a Cr-Ni-Nb-Mn-N austenitic steel of hard machinability. The machining tests were carried out under three different machining conditions: dry machining, external cutting fluid (conventional method), and with the toolholder proposed. As result, the developed system allows a surface roughness up to 10% better than dry machining and a tool life close to the conventional method, but 32% superior to dry machining; moreover, there are environmental and economics advantages once the cooling fluid is maintained in a loop circuit.