PATRICIA DA SILVA PAGETTI DE OLIVEIRA

PATRICIA DA SILVA PAGETTI DE OLIVEIRA

Página do item completo

Resultados de Busca

Agora exibindo 1 - 5 de 5

Knowledge base about risk and safety of nuclear facilities to support analysts and decision-makers
2021 - VIEIRA NETO, ANTONIO S.; OLIVA, AMAURY M.; OLIVEIRA, PATRICIA da S.P. de; HUNOLD, MARCOS C.; SAUER, MARIA E.L.J.; ANDREA, VINICIUS
Epistemic uncertainty (related to lack of knowledge), often found in the documentation of nuclear facility engineering projects, can affect the decision-making process of managers and analysts on safety and risk issues. This article conceptualizes the nature of the major uncertainties involved in engineering projects. It describes a knowledge base developed to gather data and information related to an Open-Pool Light-water Research Reactor (OPLRR) project and whose purpose is to assist professionals who work in nuclear facilities. To reduce the epistemic uncertainties that may arise in the project, the OPLRR knowledge base is designed with a set of information that allows identifying and facilitating the forwarding of solutions to address inconsistencies and/or pending issues that may exist in the project. In this sense, the information and the documents related to the project are organized in a graphical and hierarchical architecture, allowing the knowledge base users to quickly and easily obtain information regarding the systems, processes, equipment, and components of the project. Besides that, a set of documents containing descriptions, reliability data, and some other information about the systems and components are specially created to the knowledge base, and it is crucial to reduce epistemic uncertainties once it raises the issues and the inconsistencies of the project, as well as it clarifies the interrelations between the systems, the functioning of the equipment, their failures modes and the consequences of their failures, and some other data, which are not originally contained in the documents of the project.
Knowledge base about risk and safety of nuclear facilities to support analysts and decision makers
2019 - VIEIRA NETO, ANTONIO S.; OLIVA, AMAURY M.; SAUER, MARIA E.L.J.; HUNOLD, MARCOS C.; OLIVEIRA, PATRICIA da S.P.de; ANDREA, VINICIUS
Epistemic uncertainty (uncertainty related to lack of knowledge), often found in the documentation of nuclear facility engineering projects, can affect the decision-making process of managers and analysts on safety and risk issues. This article conceptualizes the nature of the major uncertainties involved in engineering projects and describes a knowledge base developed in order to gather data and information related to the project of an Open-Pool Light-water Research Rector (OPLRR) and whose purpose is to assist professionals who work in the áreas of safety, design, operation, and maintenance of nuclear facilities. In order to reduce the epistemic uncertainties that may rise in the project, the OPLRR knowledge base is designed to contain a set of information that allows identifying and facilitating the forwarding of solutions to address inconsistencies, and/or pending issues that may exist in the project. In this sense, the information and the documents related to the project are organized in a graphical and hierarchical architecture, allowing the knowledge base users to quickly and easily obtain information regarding the systems, processes, equipment, and components of the Project. Besides that, a set of documents containing descriptions, reliability data and some other important information about the systems and components are specially created to the knowledge base and it is crucial to reduce epistemic uncertainties, once it raises the issues and the inconsistencies of the project, as well as it clarifies the interrelations between the systems, the functioning of the equipment, their failures modes and the consequences of their failures, and some other data, which are not originally contained in the documents of the project.
A reliability-based strategy for the analysis of single proton exchange membrane fuel cells
2019 - OLIVEIRA, PATRICIA da S.P. de; ANDREA, VINICIUS; SANTIAGO, ELISABETE I.; LOPES, THIAGO; ANDRADE, DELVONEI A. de; LINARDI, MARCELO
The development of power conversion systems based on fuel cells has been demanding reliability studies since the requirements associated with cost and durability of these technological products have become fundamental to their acceptance by the energy market. The experimental part of the reliability study presented in this work consisted of performing life tests with single proton exchange membrane fuel cells (PEMFCs). The proposed reliability analysis methodology covered the application of qualitative and quantitative techniques. In the qualitative approach, a Failure Mode and Effect Analysis was developed in order to identify and evaluate all potential failures associated with the operation of fuel cells. In the quantitative approach, a statistical analysis was applied to the sample data generated in long-term steady-state tests of these devices. A two-parameter exponential distribution was fitted to data and the maximum likelihood estimate for the mean time to failure (MTTF) of the fuel cells was calculated. It is important to point out that the tests performed under the scope of this study were the first long-term experiments performed with the fuel cells produced in the laboratories of IPEN-CNEN/SP, Brazil. Although the results indicated that fuel cell performance and durability were still at a level below the targets normally established for similar commercial devices, the improvement of the main components of PEMFCs has been the objective of several projects developed at the institute. Thus, the main benefit brought by this study is the proposed methodology, which can be implemented as part of a reliability growth analysis of the fuel cells and can be integrated into the design process of these devices.
The impact of the operational parameters on the PEM fuel cell long-term performance
2016 - ANDREA, V.; OLIVEIRA, P.S.P.; SANTIAGO, E.I.; LINARDI, M.
Durability represents one of the major barriers to the progress of the Proton Exchange Membrane Fuel Cells (PEMFCs). To elucidate the degradation of these devices, it is important to understand the issues regarding the long-term operation of PEMFCs. Thus, in this work it was analyzed the influence of the operational parameters such as relative humidity, cell temperature and the reactant flow rates on the long-term performance through experiments of 500 hours at steady state. It was observed that the degree of humidification strongly influences on the long-term performance. The test which presented the lowest global loss of performance (with both irreversible and reversible losses) was the one with the temperatures of the humidifiers and cell all set as 75°C and the reactants flow rates set as 300 and 200 ml.min-1 for the H2 and O2, respectively. Therefore, the water management is a key point in order to obtain better performances in long-term operation of PEMFCs.
Implementation of a laboratory infrastructure for the development of reliability and durability studies of proton exchange membrane fuel cells at UIPEN-CNEN/SP
2012 - ANDREA, VINICIUS; OLIVEIRA, PATRICIA da S.P. de; LINARDI, MARCELO