A systematic control strategy is proposed for optimal operation of plants containing integrated process units in the event of unit shutdowns or failures. This entails manipulating the degrees-of-freedom available during and after a shutdown in such a way that production is restored in a cost-optimal fashion while meeting all safety and operational constraints. In this work, we investigate the problem of coordinating various buffer tanks and recycle streams during the period of transition to minimize production losses. The problem is cast in a dynamic optimization framework. The case studies in our work are based on a simulation of a Kraft pulp mill where a process unit is shut down and taken off-line for a period of time, and is subsequently restored. Based on an estimate of the downtime, our proposed control system then computes and implements a set of optimal control trajectories that accommodates the shutdown. This work extends prior studies ([8], [24]) by considering in addition two key issues -inclusion of feedback mechanisms to counter uncertainty, and the development of a software-based modeling tool. The downtime estimate is a crucial parameter for performing the control calculations. This estimate will usually be based on past operational experience or on direct information about the prognosis of the shutdown. In practice, this estimate will not correspond exactly to the actual downtime; thus we consider re-optimization based on revised downtime estimates. The remainder of the trajectory is re-optimized from the current state of the system, and the controller performs what is essentially a mid-course correction. This feedback approach has considerable advantages over a multi-scenario optimization approach for dealing with uncertainty in the estimated downtime, in that the resulting control trajectories are less conservative. The performance of this re-optimization scheme is studied in this work under various failure scenarios. Uncertainty also exists due to model imperfections and unmeasured disturbances. We therefore account for this uncertainty by considering the trajectory optimization problem within an integrated nonlinear predictive control framework. The type of operation under consideration (response to partial shutdown conditions) is inherently unsteady in nature, and the control horizon as measured from the onset of the failure is fixed. Among the distinctive features of the controller are: a shrinking prediction horizon, an economics-driven objective function and the use of a nonlinear differential-algebraic equation-based model. The controller is also "event-cognizant" in the sense that explicitly known future events such as shutdowns and startups can be specified and accommodated within the prediction algorithm. Case studies demonstrating the performance of the overall feedback strategy are presented. In the course of this work, we developed a specialized software-based modeling tool that simplifies the tasks of representing, discretizing, and solving dynamic optimization problems. The main component of this tool is a domain-specific language named MLDO (Modeling Language for Dynamic Optimization). This tool is tailored to the representation of constructs specific to the dynamic optimization problem domain. Models written in MLDO are used as a precursors for generating intermediate AMPL-based models (discretized using an implicit Runge-Kutta method), which are subsequently solved using a large-scale nonlinear optimizer, IPOPT. / Thesis / Master of Applied Science (MASc)

Shutdown maintenance projects are an intergral part of any plant maintenance system. When a plant is shutdown, production stops and major maintenance work and modification of components is carried out. Whatever the size and scope of the shutdown, component project management. is vital if the shutdown project is to be completed successfully. This autnor has found that there is little or no literature available that treats shutdown maintenance projects as a complete study. The study of the management organisation and structure, as well as the associated resources and services required by a shutdown project manager has been neglected. The aim of this thesis project is to research and investigate shutdown maintenance and to present it as a complete study. All the aspects of shutdown maintenance project management are dealt with. This is done in tne following way. Shutdown maintenance is defined with specific objectives. Then the management organi sati on. and structure, as well as the resources and services required for shutdown projects are discussed. The shutdown project management procedure and techniques are dealt with next, and finally there is a section on the effect of condition based maintenance on shutdown maintenance projects. This thesis project serves to provide a complete perspective on snutdown proJects where this was found to be lacking in previous literature on maintenance management. This thesis provides a useful source of instruction and information to an engineer who for the first time has been given a shutdown project to complete.

The statistics from the US Department of Energy show that about one-third of the total consumption of electricity in the households and industries is due to the Air Conditioning and Refrigeration (AC & R) systems. This wide usage has prompted many researchers to develop models for each of the components of the vapor compression systems. However, there has been very little information on developing simulation models that have been validated for the conditions of start-up/shutdown operations as well as vapor compression system faults. This thesis addresses these concerns and enhances the existing modeling library to capture the transients related to the above mentioned conditions. In this thesis, the various faults occurring in a vapor compressor cycle (VCC) have been identified along with the parameters affecting them. The transients of the refrigerant have also been studied with respect to the start-up/shutdown of a vapor compression system. All the simulations related to the faults and start-up/shutdown have been performed using the vapor compression system models developed in MATLAB/Simulink environment and validated against the 3-ton air conditioning unit present in the Thermo-Fluids Control Laboratory at Texas A & M University. The simulation and validation results presented in this thesis can be used to lay out certain rules of thumb to identify a particular fault depending on the unusual behavior of the system thus helping in creating certain fault diagnostic algorithms and emphasize the importance of the study of start-up/shutdown transient characteristics from the point of actual energy efficiency of the systems. Also, these results prove the capability and validity of the finite control volume models to describe VCC system faults and start-up/shutdown transients.

No description available.

Inspired by the lack of Congressional compromise during the 2013 federal shutdown, I explore how compromise works in large groups and representative bodies. An on-line survey, personal interviews, and a discourse analysis of the Congressional Record yield a diverse collection of data, including personal and public stories of compromise. I examine the stories and other data through an eclectic mix of contemporary scholarship, borrowing literary theory from the Russian critic Mikhail Bakhtin, socio-linguistic concepts from American linguist James Paul Gee, and moral philosophy from Israeli thinker Avishai Margalit. I also incorporate the work of political scientists Amy Gutmann and Dennis Thompson, as well as the political campaign coverage of writer and essayist Joan Didion. My examination shows that differences in Discourse, Gee’s expansive model of the discourse community, underpin the uncompromising mindset that dominated the 2013 shutdown. I show that public and personal compromise have obvious differences in terms of scope and complexity, but that all successful compromises, of any size, rest on a bedrock of trust. My research uncovered more effective ways of brokering legislative compromise in the future. I also learned that public opinion polls do not influence legislative decisions. Instead, regular, personal contact, whether by phone, fax, or e-mail, is the best way to engage and influence legislators. Finally, I consider the challenges and limitations of my research, including the difficulty of collecting a large, diverse survey sample, and scheduling personal interviews with public officials.

A presente dissertação investiga a adequação do método da Corrente Crítica para a programação dos projetos de parada de plataformas marítimas de exploração de petróleo, que envolvem processos de tomada de decisões em condições de risco. O método da Corrente Crítica (Critical Chain Project Management - CCPM), baseado na Teoria das Restrições (TOC), se propõe a oferecer instrumentos de controle mais precisos e focados que os tradicionalmente utilizados no método do Caminho Crítico (Critical Path Method - CPM), indicando em que momento agir, onde e como deve ser direcionada a ação. A hipótese subjacente à pesquisa é a de que a Corrente Crítica (CCPM) traduz, de forma mais adequada que o Caminho Crítico (CPM), a incerteza existente na parada de plataforma, permitindo a elaboração de um cronograma a um só tempo mais realista e mais desafiador, no sentido de atender metas de menor interrupção na produção. Com base nessa hipótese, as duas principais perguntas que nortearam toda a investigação foram: 1. O método da Corrente Crítica é adequado à programação da parada de plataformas marítimas de exploração de petróleo? 2. Que vantagens poderia trazer em comparação aos métodos tradicionais de programação de projetos em uso nas paradas de plataformas? Para responder a tais perguntas, além de revisar a bibliografia existente sobre o assunto, optou-se por coletar depoimentos de diversos especialistas do setor, por meio de três abordagens qualitativas: pesquisa-ação, entrevistas semi-estruturadas e grupo focal. A análise e interpretação dos dados revelaram que, devido aos seus instrumentos de controle de restrição de recursos serem mais afinados, o Método da Corrente Crítica (CCPM) é mais adequado ao problema da parada de plataformas marítimas - caracterizado pelo ambiente de alta limitação de recursos e por grande paralelismo de atividades. O presente estudo leva a concluir que a implantação do novo método, por oferecer aos gestores ferramentas mais precisas de controle, resulta em melhores chances de cumprimento do prazo dos projetos. / The present study discusses the adequacy of the Critical Chain Project Management Method (CCPM) - also known as the Critical Chain Method - for scheduling projects involving shutdowns on oil platforms, as such projects involve decision-making processes under risk conditions. The CCPM is based on the Theory of Constraints and aims at providing more precise and more clearly focused control instruments than those traditionally used in the Critical Path Method (CPM). The CCPM also indicates the best moments to act and where and how the action should be directed. The hypothesis underlying the research is that the CCPM portrays, more adequately than the CPM, the uncertainty that exists in a platform shutdown. This characteristic also makes it possible to draw up a schedule that is both more realistic and more challenging, as it addresses the goal of causing less interruption of production. On the basis of this hypothesis, the two main questions that oriented the entire investigation were: 1) Is the CCPM suitable for scheduling the shutdown of an offshore oil platform and, 2) What advantages might it have over the traditional scheduling methods in use on platform shutdown? To answer these questions the authors reviewed the existing bibliography on the topic and made direct on-site observations during an actual shutdown. In addition, interviews were held with a number of specialists in the area using qualitative approaches, namely, semi-structured interviews, focus groups, and action research. The Data analysis revealed that the instruments used in the CCPM for controlling the constraints of resources are more refined, so the method has been proven to be more adequate than others for facing problems that come up in offshore platform shutdowns, which are characterized by strict constraints on resources and considerable parallelism of activities. The results have led to the conclusion that the implementation of the CCPM provides managers with more precise tools for control than the CPM, and may thus increase the chances for complying with the timeframes set down for projects.

Made available in DSpace on 2017-07-10T16:32:30Z (GMT). No. of bitstreams: 1 Rosevete M Tesser.pdf: 861852 bytes, checksum: 4c22e6c8344657fc3440f75cffc2792b (MD5) Previous issue date: 2016-02-02 / The transformations inherent in the political and economic changes interfere in the organizational environment and challenges the people management area when it comes to attracting and retaining staff. In order to identify which factors motivate impact on employee turnover in the industrial sector of garment in the Southwest of Parana, businesses and employees that make up the companies in this segment participated in the survey. The methodology used the exploratory and descriptive research to raise a survey of qualitative and quantitative approach. The data were collected between June to October 2015 in 41 garment industries in the sector of Paraná Southwest region. Data collection was conducted through a questionnaire administered to 207 employees who voluntarily requested his resignation and 211 questionnaires were applied in industries that registered shutdown of employees at this period. The Likert scale was the means of detecting the frequency of the views of employees and survey respondents companies. To provide greater consistency to the findings, the data were analyzed statistically, using cause and effect diagram and Pareto chart. Statistical analyzes were prepared with Minitab software, version 17. It was found that the factors that impact for the voluntary termination of the employee's southwestern Paraná clothing industry are factors related to personal reasons, city change and change for the non-industrial sector. The wage factor also had its relevance. Among the factors that impact for employee termination by the industry, the financial situation due to the current economic climate was the most led the industry to turn off people during the survey period, however as internal factors fulfillment of production targets and absenteeism leads the management area of human resources or companies the need to implement actions that can minimize these factors. Therefore, it is concluded that it is the factors related to the voluntary resignation of the employee or the factors related to termination by the company, both have consequence in the economic, financial or social aspect of firms and households operating in the clothing sector. / As transformações inerentes às mudanças políticas e econômicas interferem no ambiente organizacional e desafiam a área de gestão de pessoas no que tange a atração e retenção de pessoas. Com objetivo de identificar quais os fatores impactam a rotatividade no setor industrial do vestuário do Sudoeste do Paraná, empresas e funcionários que compõem as empresas deste segmento participaram da pesquisa. Portanto na metodologia utilizou-se a pesquisa exploratória e descritiva para um levantamento de abordagem quali-quantitativa. Os dados foram coletados no período de junho a outubro de 2015 em 41 indústrias do setor do vestuário da região Sudoeste do Paraná. A coleta foi realizada por meio de um questionário aplicado a 207 funcionários que voluntariamente solicitaram seu desligamento e 211 questionários foram aplicados nas indústrias que registraram desligamento de funcionários neste período. A escala de Likert foi o meio de detectar a frequência das opiniões dos funcionários e empresas respondentes da pesquisa. Para proporcionar maior consistência às conclusões, os dados foram submetidos a tratamento estatístico, utilizando-se do Diagrama causa e efeito e do Gráfico de Pareto. As análises estatísticas foram elaboradas no software Minitab, versão 17. Constatou-se que os fatores que impactaram para o desligamento voluntário, do funcionário da indústria do vestuário do Sudoeste do Paraná, são fatores relacionados aos motivos pessoais, a mudança de cidade e mudança para o setor não industrial, o fator salário também teve sua relevância. Dentre os fatores que impactaram para o desligamento do funcionário pela indústria, a situação financeira por conta do cenário econômico atual foi o que mais levou a indústria a desligar pessoas no período da pesquisa, porém como fatores internos o cumprimento das metas de produção e absenteísmo leva à área de gestão de pessoas ou recursos humanos das empresas a necessidade de, implantar ações que possam minimizar estes fatores. Portanto, observa-se com a pesquisa que, independente do cenário econômico e ou os desligamentos voluntários dos trabalhadores, ambos trazem consequência seja no aspecto econômico, financeiro ou social das empresas e famílias que atuam no setor.

<p>Skolfartyget M/S Calmare Nyckel, som ägs och opereras av Sjöfartshögskolan i Kalmar används i utbildningssyfte av både blivande nautiker och maskinbefäl.</p><p> </p><p>Driften av NOHAB-dieseln, som används som generator, har varit problemfylld med ständiga och oförklarliga stopp. Det larmsystem som installerades av Oskarshamnsvarvet var högst bristfälligt. Larmsystemet var personfarligt då det var byggd på 230volt, dessutom var larmpunkterna byggda i serie med endast en stoppindikering. Avsaknaden av elritningar över systemet gjorde att bristerna i larmsystemet inte kunde felsökas.<strong> </strong>Dessutom fanns ingen indikering i kontrollrummet utan endast lokalt vid NOHAB-dieseln.</p><p> </p><p>Vi har gjort en nyinstallation av larmsystemet på mer personsäkra 24VDC, med samtliga larmpunkter parallella och med tillhörande indikering på panel, både lokalt vid NOHAB-dieseln samt i pulpeten för god översyn av systemet. Vidare har vi gjort kompletta ritningar över systemet för en god överblick och möjlighet att felsöka.</p><p>I rapporten beskriver vi tillvägagångssättet för problemlösningar som uppstått under arbetet med att skapa ett fungerande larmsystem.</p> / <p><em> </em>School ship M/S Calmare Nyckel, owned and operated by the Maritime University of Kalmar is used for training by both prospective merchant marine officer as well as engineers. The operation of NOHAB-diesel, used as a generator, has been problematic with frequent and unexplained stop. The alarm system installed by the Oskarshamn Shipyard was highly dysfunctional. The alarm system was dangerous to personnel when it was built on 230volt, furthermore were the alarm points constructed in series with only a stop indication. The lack of electrical drawings of the system made it impossible to trouble shot the deficiencies in the alarm system. Moreover, there was no alarm indication in the control room but only locally at the NOHAB-diesel.</p><p> </p><p>We have made a new installation of the alarm system with the higher personal safety 24VDC, with all the alarms parallel with the corresponding indication on the panel, both locally at the NOHAB-diesel and on the control table for good review of the system. Furthermore, we have made complete drawings of the system enabling a good overview and the ability to troubleshoot.In this report we describe the approach to the problem solutions that have emerged in the process of creating a functioning alarm system.</p>

Skolfartyget M/S Calmare Nyckel, som ägs och opereras av Sjöfartshögskolan i Kalmar används i utbildningssyfte av både blivande nautiker och maskinbefäl.   Driften av NOHAB-dieseln, som används som generator, har varit problemfylld med ständiga och oförklarliga stopp. Det larmsystem som installerades av Oskarshamnsvarvet var högst bristfälligt. Larmsystemet var personfarligt då det var byggd på 230volt, dessutom var larmpunkterna byggda i serie med endast en stoppindikering. Avsaknaden av elritningar över systemet gjorde att bristerna i larmsystemet inte kunde felsökas. Dessutom fanns ingen indikering i kontrollrummet utan endast lokalt vid NOHAB-dieseln.   Vi har gjort en nyinstallation av larmsystemet på mer personsäkra 24VDC, med samtliga larmpunkter parallella och med tillhörande indikering på panel, både lokalt vid NOHAB-dieseln samt i pulpeten för god översyn av systemet. Vidare har vi gjort kompletta ritningar över systemet för en god överblick och möjlighet att felsöka. I rapporten beskriver vi tillvägagångssättet för problemlösningar som uppstått under arbetet med att skapa ett fungerande larmsystem. / School ship M/S Calmare Nyckel, owned and operated by the Maritime University of Kalmar is used for training by both prospective merchant marine officer as well as engineers. The operation of NOHAB-diesel, used as a generator, has been problematic with frequent and unexplained stop. The alarm system installed by the Oskarshamn Shipyard was highly dysfunctional. The alarm system was dangerous to personnel when it was built on 230volt, furthermore were the alarm points constructed in series with only a stop indication. The lack of electrical drawings of the system made it impossible to trouble shot the deficiencies in the alarm system. Moreover, there was no alarm indication in the control room but only locally at the NOHAB-diesel.   We have made a new installation of the alarm system with the higher personal safety 24VDC, with all the alarms parallel with the corresponding indication on the panel, both locally at the NOHAB-diesel and on the control table for good review of the system. Furthermore, we have made complete drawings of the system enabling a good overview and the ability to troubleshoot.In this report we describe the approach to the problem solutions that have emerged in the process of creating a functioning alarm system.

Submitted by Maria Eneide de Souza Araujo (mearaujo@ipen.br) on 2015-02-20T15:58:48Z No. of bitstreams: 0 / Made available in DSpace on 2015-02-20T15:58:48Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado em Tecnologia Nuclear) / IPEN/D / Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP