This research has first reviewed the current status and future aspects of marine and offshore safety assessment. The major problems identified in marine and offshore safety assessment in this research are associated with inappropriate treatment of uncertainty in data and human error issues during the modelling process. Following the identification of the research needs, this thesis has developed several analytical models for the safety assessment of marine and offshore systems/units. Such models can be effectively integrated into a risk-based framework using the marine formal safety assessment and offshore safety case concepts. Bayesian network (BN) and fuzzy logic (FL) approaches applicable to marine and offshore safety assessment have been proposed for systematically and effectively addressing uncertainty due to randomness and vagueness in data respectively. BN test cases for both a ship evacuation process and a collision scenario between the shuttle tanker and Floating, Production, Storage and Offloading unit (FPSO) have been produced within a cause-effect domain in which Bayes' theorem is the focal mechanism of inference processing. The proposed FL model incorporating fuzzy set theory and an evidential reasoning synthesis has been demonstrated on the FPSO-shuttle tanker collision scenario. The FL and BN models have been combined via mass assignment theory into a fuzzy-Bayesian network (FBN) in which the advantages of both are incorporated. This FBN model has then been demonstrated by addressing human error issues in a ship evacuation study using performance-shaping factors. It is concluded that the developed FL, BN and FBN models provide a flexible and transparent way of improving safety knowledge, assessments and practices in the marine and offshore applications. The outcomes have the potential to facilitate the decision-making process in a risk-based framework. Finally, the results of the research are summarised and areas where further research is required to improve the developed methodologies are outlined.

This research has reviewed the current status of offshore and marine safety. The major problems identified in the research are associated with risk modelling under circumstances where the lack of data or high level of uncertainty exists. This PhD research adopts an object-oriented approach, a natural and straightforward mechanism of organising information of the real world systems, to represent the Offshore Gas Supply Systems (OGSSs) at both the component and system levels. Then based on the object-oriented approach, frameworks of aggregative risk assessment and fault tree analysis are developed. Aggregative risk assessment is to evaluate the risk levels of components, subsystems, and the overall OGSS. Fault trees are then used to represent the cause-effect relationships for a specific risk in the system. Use of these two assessment frameworks can help decision makers to obtain comprehensive view of risks in the OGSS. In order to quantitatively evaluate the framework of aggregative risk, this thesis uses a fuzzy aggregative risk assessment method to determine the risk levels associated with components, subsystems, and the overall OGSS. The fuzzy aggregative risk assessment method is tailored to quantify the risk levels of components, subsystems, and the OGSS. The proposed method is able to identify the most critical subsystem in the OGSS. As soon as, the most critical subsystem is identified, Fuzzy Fault Tree Analysis (FFTA) is employed to quantitatively evaluate the cause-effect relationships for specific undesired event. These results can help risk analysts to select Risk Control Options (RCOs) for mitigating risks in an OGSS. It is not financially possible to employ all the selected RCOs. Therefore, it is necessary to rank and select the best RCO. A decision making method using the Fuzzy TOPSIS (FTOPSIS) is proposed to demonstrate the selection of the best RCOs to control the existing risks in the system. The developed models and frameworks can be integrated to formulate a platform which enables to facilitate risk assessment and safety management of OGSSs without jeopardising the efficiency of OGSSs operations in various situations where traditional risk assessment and safety management techniques cannot be effectively applied.

This research is carried out to improve Human Reliability Analysis (HRA) in oil tanker operations in general, to extend and enhance in specific Cognitive Reliability and Error Analysis Method (CREAM), with the aim of reducing human error and thus subsequently preventing oil tanker spills. It is concentrated on oil tanker operations to address the limitation of availability of human reliability data in the maritime domain. The continual occurrence of oil tanker spills, which was substantiated with analysis of historical data of oil tanker incidents/accidents from 1970 to 2008, provides a judicious reason to conduct this research. The critical review of Formal Safety Assessment (FSA) and HRA results in the development of a conceptual framework of HRA facilitating FSA and incorporating Human Organisational Factors (HOF), which addresses the shortcomings of the generic HRA and FSA methodologies that exist independently in the management of oil tankers to prevent oil spills. The CREAM is reviewed due to its prominent use in identifying the root causes of human error. However, its inability of providing solutions to an incident/accident investigation and robust quantification of human reliability features stimulates the development of an advanced CREAM and a human reliability quantification model using a combined Analytic Hierarchical Process (AHP) and fuzzy logic approach in this research. In addition to facilitating identification of the root causes of human error, the advanced CREAM also provides the solutions to a quantification model, which enables the development of HRA data in the maritime domain. Furthermore, lack of CREAM studies on relationships among Common Performance Conditions (CPCs) is addressed by proposing a Decision Making Trial and Evaluation Laboratory (DEMATEL) model, which allows for a comprehensive understanding of relationships and interdependencies among the CPCs. The model could also be used toappreciate and assimilate the relationships and interdependencies among human factor variables involved in other transportation systems and industrial fields. Finally, the research is concluded with an integrated AHP and fuzzy Technique for Order Preference by Similarity to the Ideal Solution (TOPSIS) model for determining the selection of an appropriate risk control option (RCO) while performing an incident/accident investigation by taking subjective judgments of decision makers into consideration. This research as a pioneer work in developing and applying advanced techniques to improve the generic CREAM in oil tanker operations establishes a foundation for future effort to improve the use of CREAM in other industries. The techniques developed can also be tailored to investigate and deal with an incident/accident effectively, resulting in the reduction of human error within the system management of any organisation.

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Resumo: A turbina Michell-Banki é basicamente uma máquina de ação, sendo que a característica mais importante das turbinas de ação é a não existência do tubo de sucção. A instalação do tubo de sucção numa turbina causa o aumento da queda disponível e como conseqüência, aumenta a potência gerada e a rotação da turbina. No presente trabalho propõe-se a instalação de um tubo de sucção numa turbina Michell-Banki, visando alcançar as melhorias já indicadas acima, lembrando que ao colocar o tubo de sucção aparece um grau de reação na máquina. Foi feito uma análise mecânica-hidráulica da turbina Michell-Banki proposta, com o objetivo de encontrar as equações que permitem calcular os diversos elementos da turbina. Desta maneira o trabalho apresenta uma metodologia para projeto de uma turbina Michell-Banki com tubo de sucção. Também são apresentadas as formas de traçar o rotor, o injetor e a pá diretriz. Finalmente o trabalho apresenta ainda as recomendações para a execução de projeto e construção da turbina. / Abstract: The turbine Michell-Banki is basically an action machine, and the important characteristic of the action turbines is the no existence of the suction tube. The installation of the suction tube in a turbine increases the available fall and as consequence, it increases the generated power. The rotation of the turbine is also increased by increasing the available fall. In the present work it's proposed the installation of a suction tube in a Michell-Banki turbine, aiming to reach the improvements already indicated above, remembering that when placing the suction tube a reaction degree appears in the machine. It was done an mechanical and hydraulics analysis of the Michell-Banki turbine with the objective of finding the equations that allow to calculate the several elements of the turbine proposed, and thus presenting a methodology for project of a turbine. Finally I described the way of drawing the rotor, the injector and the guideline shovel, as well as it is also recommended the process that should be followed to build the turbine. / Orientador: Luiz Roberto Carrocci / Coorientador: Paulo Magalhães Filho / Banca: Petronio Masanobu Tanisho / Banca: José Carlos Cesar Amorim / Mestre

Made available in DSpace on 2014-06-11T19:24:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2004-01-30Bitstream added on 2014-06-13T18:21:00Z : No. of bitstreams: 1 alexandre_db_me_botfca.pdf: 3742670 bytes, checksum: 98e41e6dc4b4d0b4dc5de6f363be576f (MD5) / Universidade Estadual Paulista (UNESP) / O Brasil é o país que possui uma das maiores reservas mundiais de hidroenergia, em razão da quantidade imensa de rios em seu território. Em diversas áreas isoladas, tais como grupos populacionais dispersos em áreas rurais, a mais importante alternativa de produção e utilização de energia renovável é representada pelas Micro, Mini e Pequenas Centrais Hidrelétricas, que promovem oferta de energia elétrica utilizando pequenos aproveitamentos hidroenergéticos. Para pequenos aproveitamentos, o projetista de uma central hidrelétrica deve, ao definir o tipo de turbina hidráulica, fixar-se nos rotores Pelton, Francis e Kaplan e nas turbinas Banki, por serem os mais freqüentemente encontrados na prática usual. O projeto destes aproveitamentos hidroenergéticos requer muitos detalhes, regras e cálculos matemáticos que exigem tempo e conhecimento do assunto, tornando desejável uma ferramenta que forneça, de forma rápida e clara, a informação sobre os dados envolvidos no dimensionamento de equipamentos. Na sociedade moderna, tal necessidade de informação é constantemente suprida pela informática, com o uso de softwares específicos para o assunto em foco. Com esta idéia, foi desenvolvido o presente trabalho, considerando-se que a criação de um software que atende aos requisitos dos projetos de aproveitamentos hidroenergéticos executa o papel importante de ser uma ferramenta de desenvolvimento da eletrificação rural. Este trabalho pretende, especificamente para geração de energia elétrica através de pequenas centrais hidrelétricas, estabelecer um roteiro completo para pré-dimensionar turbinas hidráulicas, implementar este roteiro em sistema computacional, e criar uma interface de software de fácil uso. A partir das variáveis: vazão do rio, altura de queda do rio, e altitude local, as quais são fornecidas pelo usuário... / Brazil is the country that possesses one of the largest world reservations of hydraulic power, in reason of the immense amount of rivers in its territory. In diverse isolated areas, such as dispersed population groups in rural areas, the most important alternative of production and use of renewable energy is represented by the Micro, Mini and Small Hydroelectric Power Stations, that promote offer of electric energy using small uses hydroelectric power. For small uses, the planner of hydroelectric power plants, when defining the type of hydraulic turbine, to fix itself in the Pelton, Francis and Kaplan rotors and in the Banki turbines, for they be more frequently the found in the usual practice. The project of these uses hydroelectric power requests many details, rules and mathematical calculations that demand time and knowledge of the subject, turning desirable a tool that supplies, in a fast and simple form, the information on the data involved in the sizing of equipment. In the modern society, such need of information constantly is supplied by computer science, with the use of specific software for the subject in focus. With this idea, the present work was developed, being considered that the creation of a software that assists to the requirements of the projects of uses hydroelectric power executes the important paper of being a tool of development of the rural electrification. This work intends, specifically for generation of electric energy through small Hydroelectric Power Stations, to establish a complete guide of orientation for to make initial calculations of the dimensions of hydraulic turbines, to implement this guide of orientation in computational system, and to create an interface of software of easy use. Starting from the variables: outflow of the river, height of fall of the river, and local altitude, which is supplied by the user... (Complete abstract click electronic access below)

Made available in DSpace on 2014-06-11T19:24:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-12-13Bitstream added on 2014-06-13T19:52:20Z : No. of bitstreams: 1 silva_gj_me_botfca.pdf: 760401 bytes, checksum: a6ec706f91a41e6db106a279f537ec20 (MD5) / Universidade Estadual Paulista (UNESP) / O presente estudo é uma proposta de sistema computacional de código aberto (open source), desenvolvido em linguagem PHP para dimensionar sistemas de irrigação por pivô central. O modelo realiza uma análise hidráulica do sistema, selecionando bocais a partir dos valores de pressão e vazão determinados ao longo da linha lateral, na presença e na ausência de canhão final, com ou sem o uso de reguladores de pressão, de tal forma a permitir uma adequada aplicação de água. O sistema foi desenvolvido com ferramentas gratuitas, conforme a proposta de trabalho LAMP (Linux,Apache,Mysql,PHP). Os programas de dimensionamento e avaliação foram projetados para funcionarem na Internet, como módulos do gerenciador de conteúdo Phpwebthings, onde poderão receber correções, atualizações e melhoramentos. / This study is a proposal of an open source computational system developed in PHP language to design center pivot irrigation systems. A model can select sprinkles from final lateral pressure and shows a hydraulic analysis system with flow values along the lateral, with or without end gun, with or without pressure regulators, allowing an adequate water application. The system was developed through a free tools, according to LAMP ( Linux, Apache, Mysql, PHP). The evaluation programs were designed for working in internet, as a module management of the phpwebthings content, where it can receive corrections, up-to-dating and improving.

Thesis (MTech(Civil Engineering))--Cape Peninsula University of Technology, 2006. / The performance of a centrifugal pump is altered for slurry or viscous materials (Stepanoff, 1969) and this needs to be accounted for. Usually, the suitable selection and evaluation of centrifugal pumps is based only on water pump performance curves supplied by the pump manufacturer (Wilson, Addie, Sellgren & Clift, 1997). In 1984 Walker and Goulas conducted a number of pump performance tests with kaolin clay slurries and coal slurries on a Warman 4/3 AH horizontal slurry pump and a Hazleton 3-inch B CTL horizontal pump (Walker and Goulas, 1984). Walker and Goulas have analysed the test data and correlated the performance derating both at the best efficiency flow rate (BEP) and at 10% of the best efficiency flow rate (0.1 BEP) to the modified pump Reynolds number (NRep). They have noticed that the head and the efficiency reduction ratio decreased for the pump Reynolds number less then 10⁶. Furthermore, Walker and Goulas obtained a reasonably good agreement (± 5%) between pump test data for non-Newtonian materials and pump performance prediction using the Hydraulics Institute chart. Sery and Slatter (2002) have investigated pump deration for non-Newtonian yield pseudoplastic materials. The NRep was calculated using the Bingham plastic viscosity (µp). Results have shown good agreement with regard to head and efficiency reduction ratios in comparison with previous work. However, Sery and Slatter's pump performance correlation using the HI chart did not reach the same conclusion. Error margin of ± 20% and ± 10% were found for head and efficiency respectively. This study is an attempt to reconcile the differences between Walker and Goulas (1984) and Sery and Slatter (2002) and extend the evaluation of these derating methods to pseudoplastic materials. The test work was conducted in the Flow Process Research Centre laboratory of the Cape Peninsula University of Technology using two centrifugal pumps; a Warman 6/4 and a GrW 4/3. The materials used were water, CMC solution bentonite and kaolin suspension at different concentrations (7% and 9% by weight for bentonite; 5%, 6% and 7% by weight for CMC; 17%, 19% and 21% by volume for kaolin).

Os defeitos superficiais são os maiores problemas de qualidade em barras laminadas a quente, representando inúmeros transtornos durante o processo produtivo, pois dependendo de suas características geram elevada rejeição durante o processo de inspeção. Elevada rejeição significa retrabalho e possível sucateamento. Dentre as diversas causas para a ocorrência de defeitos superficiais, estão os defeitos nos tarugos, a temperatura de laminação, conseqüência da temperatura de reaquecimento e ritmo de laminação e a remoção de carepa após o reaquecimento. Definiu-se o aço SAE 1043 para o desenvolvimento deste trabalho devido aos níveis de rejeição superficial e elevados volumes de produção, o que gera grande impacto na produção das linhas de inspeção. Os resultados obtidos a partir dos testes realizados demonstram que a temperatura de laminação até determinado limite não tem influência na rejeição superficial, mas que abaixo deste gera elevado índice de rejeição. O uso do descarepador tem grande influencia nos níveis de defeitos superficiais, e o controle de seus parâmetros principais é fundamental. O condicionamento superficial dos tarugos é o parâmetro que mais apresentou influência positiva sobre a rejeição superficial, demonstrando que defeitos pré-existentes na matéria-prima têm grande impacto no produto final da laminação. / Surface defects are major quality problems in hot rolled bars, representing numerous disturbances during the production process, as depending on their characteristics generate high rejection during the inspection process. High rejection means rework and scrap. Among the various causes for the occurrence of surface defects are defects in the billets, rolling temperature, a consequence of the reheating temperature and rate of roll and removal of scale after reheating. The steel SAE 1043 used in this work was selected due to its level of surface defects and high production volumes, which generates large impact on production inspection process. The results show that the rolling temperature of up to a certain limit does not influence the surface defects, but below this generates a high rate of rejection. The use of descaling has a large influence on the levels of surface defects, and control of its main parameters is essential. The surface conditioning of billets is the parameter that showed a positive influence on the reduction of surface defects, demonstrating that pre-existing defects in materials has large impact on the final rolled product.

The work was concerned with the design, analysis and basic demonstration of a novel hydraulically assisted fixed geometry turbocharger system intended to help overcome some of the transient issues associated with current automotive boosting technologies. The novel system was based upon use of relatively lightweight parts, where kinetic energy is recovered during vehicle braking, stored in a simple hydraulic accumulator and then used later on to rapidly accelerate the engine's turbocharger. The turbocharger is fitted with a replacement centre housing enclosing a small impulse turbine, rigidly mounted to the turbocharger shaft and powered by a jet of oil. The aim is one of helping the engine to accelerate the vehicle while operating in a region of much higher brake efficiency due to the reduction in exhaust backpressure when compared with competing variable geometry and/or compound boosting technologies. The specific tasks involved concept design and computational analysis, including specification of the turbine type and geometry together with the associated hydraulic parts. A production turbocharger was reverse engineered to confirm the feasibility of packaging the hydraulic turbine system into the centre housing of a typical fixed geometry design. Finally an experimental rig was designed and manufactured to allow basic demonstration of the system, with speeds of up to ~90000 rpm @ 200 bar pressure from the pump via the accumulator achieved in ~0.8 seconds and clear potential for further optimisation. This hydraulic boosting system is capable of attaining 70% efficiency (a product of 0.85 from the oil pump, 0.95 from the hydraulic accumulator and 0.88 of Pelton wheel). The system has higher power density at low cost compared to the main competitor ‘E Boosting - with efficiency in the region of 90%’. The cost of E boosting and need for 48 volt battery makes it less favourable compared to the hydraulic turbine system. The concept has been shown to offer significant potential to assist a turbocharger to spool up via a Novel Hydraulic Kinetic Energy Recovery System approach.