<p>Information technology (IT) is becoming the primary factordetermining the survival of most organizations. The differenttypes of systems and the wide range of objectives suggest thatdiverse evaluation methods are needed. There is a critical needfor a new approach to managing IT investments, and solving theinformation paradox should be a business imperative for allmanagers today.</p><p>Evaluating IT investments introduces different types ofproblems that investment in traditional assets does notconsider. The focal point shifts from measuring hard andquantifiable benefits that appear on a firm’s incomestatement to measuring soft, diffuse, and qualitativeimpact.</p><p>The decision to acquire new information technology poses anumber of serious evaluation problems for managers because theavailable methods for IT investment evaluation are mostlystatic and they do not consider dynamism in decision-makingprocesses.</p><p>Common problems with the methods for evaluating ITinvestments are related to their inability to take account ofthe full range of potential benefits. There is a gap betweentheory and practice in relation to the use of any method formaking decisions and for continuous evaluation of ITinvestments.</p><p>This thesis presents a new approach to evaluating benefitsof IT investments in a dynamic way, an approach consisting of acombination of dynamic information workflow models and businessprocess simulation techniques. The proposed approach givesmanagers and organizations the possibility of implementingother models for measuring different metrics and aspects of ITinvestments.</p><p>A dynamic information workflow model of an electric utilityandsimulation essays are presented in order to show how theproposed approach is applied. The performance measure selectedfor running experiments was efficiency, which was characterizedby the following selected performance indicators: cycle time,resource utilization, and activity costs. Empirical data wascollected from case studies of different utilities in CentralAmerican countries.</p><p><b>Key words:</b>Business Process Modeling and Simulation,Evaluating IT Investments, Dynamic Information Workflow Model,Electric Utilities.</p>

O presente trabalho envolve a elaboração de um modelo matemático para um processo industrial de produção de cloro e soda a partir de salmoura, visando sua otimização em termos de eficiência de produção e dos custos dos consumos de energia elétrica e vapor. O estudo contemplou duas etapas do processo: eletrólise e concentração de licor de NaOH por evaporação. Para a unidade de eletrólise não foram encontrados na literatura modelos fenomenológicos adequados à simulação do processo. Por essa razão, foram desenvolvidos modelos empíricos baseados em redes neurais tipo ?feedforward? constituídas por três camadas, a partir de dados da operação industrial. Para a unidade de evaporação foi elaborado um balanço de energia adequado à estimativa do consumo de vapor. Porém, devido à falta de modelos para previsão das relações de equilíbrio para o sistema, o modelo fenomenológico foi substituído por um modelo de redes neurais tipo ?feedforward? de três camadas também para essa unidade. Para ajuste dos modelos, uma base de dados foi montada a partir de dados de operação do processo da Carbocloro S.A. Indústrias Químicas, localizada em Cubatão-SP, analisados por meio de técnicas estatísticas multivariadas, visando detectar e eliminar erros grosseiros e dados anômalos, além de identificar correlações entre variáveis e diferentes regimes operacionais da planta de produção de cloro e soda. Os modelos ajustados para os diferentes circuitos de células de eletrólise, bem como para a etapa de evaporação, apresentaram boa concordância com os dados operacionais. Isto possibilitou sua utilização para simular a operação das unidades de células eletrolíticas e evaporação no processo industrial de produção de cloro-soda, com células tipo diafragma. O modelo matemático baseado em redes neurais foi utilizado em estudos de otimização do processo, de modo a maximizar o ganho financeiro na unidade industrial, para uma dada condição de operação. / The present work consists on the development of a mathematical model on an industrial chlorine and sodium hydroxide production plant, aiming at the optimization of production efficiency and costs saving concerning electrical energy and vapor consumption. Two process steps were considered in the study: electrolysis and NaOH-liquor concentration by evaporation. Since there are no adequate models reported in the literature for simulating electrolysis-based processes like the one considered, empirical models for the different types of electrolysis cells were developed based on the fitting of neural networks to operational data from industrial operation. In this case, feedforward neural networks containing three neuron layers were fitted to the data. The raw data obtained from industrial operation at Carbocloro plant, in Cubatão ? SP, were first treated by means of multivariate statistical techniques, with the purpose of detecting and eliminating data containing gross errors and outliers, as well as to identify correlations among variables and different operational regimes of the industrial plant. Although material and energy balances for the evaporation step have been initially adopted, this approach could not be used in simulations due to the lack of valid models to predict liquid ? vapor equilibria for the specific system. Thus, a neural network model was also fitted to data from operation of the evaporation step. Fitting of the neural network models resulted in good agreement between model predictions and measured values of the model output variables, and this enabled their use in simulation studies for the electrolysis and evaporation process steps. The neural network-based mathematical model was utilized in process optimization studies aiming at the best financial gain under given operational conditions.

O presente trabalho envolve a elaboração de um modelo matemático para um processo industrial de produção de cloro e soda a partir de salmoura, visando sua otimização em termos de eficiência de produção e dos custos dos consumos de energia elétrica e vapor. O estudo contemplou duas etapas do processo: eletrólise e concentração de licor de NaOH por evaporação. Para a unidade de eletrólise não foram encontrados na literatura modelos fenomenológicos adequados à simulação do processo. Por essa razão, foram desenvolvidos modelos empíricos baseados em redes neurais tipo ?feedforward? constituídas por três camadas, a partir de dados da operação industrial. Para a unidade de evaporação foi elaborado um balanço de energia adequado à estimativa do consumo de vapor. Porém, devido à falta de modelos para previsão das relações de equilíbrio para o sistema, o modelo fenomenológico foi substituído por um modelo de redes neurais tipo ?feedforward? de três camadas também para essa unidade. Para ajuste dos modelos, uma base de dados foi montada a partir de dados de operação do processo da Carbocloro S.A. Indústrias Químicas, localizada em Cubatão-SP, analisados por meio de técnicas estatísticas multivariadas, visando detectar e eliminar erros grosseiros e dados anômalos, além de identificar correlações entre variáveis e diferentes regimes operacionais da planta de produção de cloro e soda. Os modelos ajustados para os diferentes circuitos de células de eletrólise, bem como para a etapa de evaporação, apresentaram boa concordância com os dados operacionais. Isto possibilitou sua utilização para simular a operação das unidades de células eletrolíticas e evaporação no processo industrial de produção de cloro-soda, com células tipo diafragma. O modelo matemático baseado em redes neurais foi utilizado em estudos de otimização do processo, de modo a maximizar o ganho financeiro na unidade industrial, para uma dada condição de operação. / The present work consists on the development of a mathematical model on an industrial chlorine and sodium hydroxide production plant, aiming at the optimization of production efficiency and costs saving concerning electrical energy and vapor consumption. Two process steps were considered in the study: electrolysis and NaOH-liquor concentration by evaporation. Since there are no adequate models reported in the literature for simulating electrolysis-based processes like the one considered, empirical models for the different types of electrolysis cells were developed based on the fitting of neural networks to operational data from industrial operation. In this case, feedforward neural networks containing three neuron layers were fitted to the data. The raw data obtained from industrial operation at Carbocloro plant, in Cubatão ? SP, were first treated by means of multivariate statistical techniques, with the purpose of detecting and eliminating data containing gross errors and outliers, as well as to identify correlations among variables and different operational regimes of the industrial plant. Although material and energy balances for the evaporation step have been initially adopted, this approach could not be used in simulations due to the lack of valid models to predict liquid ? vapor equilibria for the specific system. Thus, a neural network model was also fitted to data from operation of the evaporation step. Fitting of the neural network models resulted in good agreement between model predictions and measured values of the model output variables, and this enabled their use in simulation studies for the electrolysis and evaporation process steps. The neural network-based mathematical model was utilized in process optimization studies aiming at the best financial gain under given operational conditions.

Information technology (IT) is becoming the primary factordetermining the survival of most organizations. The differenttypes of systems and the wide range of objectives suggest thatdiverse evaluation methods are needed. There is a critical needfor a new approach to managing IT investments, and solving theinformation paradox should be a business imperative for allmanagers today. Evaluating IT investments introduces different types ofproblems that investment in traditional assets does notconsider. The focal point shifts from measuring hard andquantifiable benefits that appear on a firm’s incomestatement to measuring soft, diffuse, and qualitativeimpact. The decision to acquire new information technology poses anumber of serious evaluation problems for managers because theavailable methods for IT investment evaluation are mostlystatic and they do not consider dynamism in decision-makingprocesses. Common problems with the methods for evaluating ITinvestments are related to their inability to take account ofthe full range of potential benefits. There is a gap betweentheory and practice in relation to the use of any method formaking decisions and for continuous evaluation of ITinvestments. This thesis presents a new approach to evaluating benefitsof IT investments in a dynamic way, an approach consisting of acombination of dynamic information workflow models and businessprocess simulation techniques. The proposed approach givesmanagers and organizations the possibility of implementingother models for measuring different metrics and aspects of ITinvestments. A dynamic information workflow model of an electric utilityandsimulation essays are presented in order to show how theproposed approach is applied. The performance measure selectedfor running experiments was efficiency, which was characterizedby the following selected performance indicators: cycle time,resource utilization, and activity costs. Empirical data wascollected from case studies of different utilities in CentralAmerican countries. <b>Key words:</b>Business Process Modeling and Simulation,Evaluating IT Investments, Dynamic Information Workflow Model,Electric Utilities. / NR 20140805

O propósito deste trabalho foi o desenvolvimento de um procedimento simulador de processo reproduzindo a etapa de destilação extrativa de uma unidade de extração de butadieno a partir de uma corrente de hidrocarbonetos na faixa de quatro átomos de carbono, através da adição do solvente n-metil-2- pirrolidona (NMP). Os resultados obtidos foram comparados e validados com dados de processo obtidos por uma unidade industrial de extração de butadieno. O aprofundamento nos conceitos do processo de separação através de uma ferramenta em simulador de processo capaz de predizer condições de operação permitiu avaliações de aumento de capacidade. A capacidade dos elementos internos dos equipamentos envolvidos na separação pode ser avaliada e a identificação do ponto inicial de engargalamento da unidade foi possível. O procedimento proposto também permite reduzir incertezas para identificação de novos pontos de engargalamento a partir de uma nova configuração dos elementos internos identificados como ineficientes com a elevação de carga processada. / The purpose of this study was the development of a model using a commercial process simulator software in order to reproduce the extractive distillation step of a butadiene extraction unit from a hydrocarbon stream by the addition of the solvent n- methyl-2-pyrrolidone (NMP). The results obtained from the simulations were compared with process data from an operational butadiene extraction unit. The knowledge of the separation process due the model should predict operating conditions allowing revamps on the actual asset. The internals capacity for the equipment involved in the separation could be evaluated and units bottlenecks points should be identified.

O propósito deste trabalho foi o desenvolvimento de um procedimento simulador de processo reproduzindo a etapa de destilação extrativa de uma unidade de extração de butadieno a partir de uma corrente de hidrocarbonetos na faixa de quatro átomos de carbono, através da adição do solvente n-metil-2- pirrolidona (NMP). Os resultados obtidos foram comparados e validados com dados de processo obtidos por uma unidade industrial de extração de butadieno. O aprofundamento nos conceitos do processo de separação através de uma ferramenta em simulador de processo capaz de predizer condições de operação permitiu avaliações de aumento de capacidade. A capacidade dos elementos internos dos equipamentos envolvidos na separação pode ser avaliada e a identificação do ponto inicial de engargalamento da unidade foi possível. O procedimento proposto também permite reduzir incertezas para identificação de novos pontos de engargalamento a partir de uma nova configuração dos elementos internos identificados como ineficientes com a elevação de carga processada. / The purpose of this study was the development of a model using a commercial process simulator software in order to reproduce the extractive distillation step of a butadiene extraction unit from a hydrocarbon stream by the addition of the solvent n- methyl-2-pyrrolidone (NMP). The results obtained from the simulations were compared with process data from an operational butadiene extraction unit. The knowledge of the separation process due the model should predict operating conditions allowing revamps on the actual asset. The internals capacity for the equipment involved in the separation could be evaluated and units bottlenecks points should be identified.

In der vorliegenden Habilitationsarbeit wurden technisch-konstruktive Lösungsansätze basierend auf einem entwickelten strömungs-thermomechanischen/magneto-hydro-dynamischen Simulationsmodell zur Entwicklung/Charakterisierung eines physikalischen Prozesswirkprinzips des betrachteten Mikro- und Hochleistungs- sowie Orbital-Plasma-Schweißprozesses und dessen physikalischer Effekte entwickelt. Dabei wurden die differenten Einflussgrößen beim Plasmaschweißprozess erfasst, analysiert und ihre Wirkung auf Schweißprozessverhalten und Brennerkonstruktion charakterisiert. Die damit gewonnenen Ergebnisse wurden zur werkstofflichen, technisch-konstruktiven Entwicklung der Brennerkopfmodelle hinsichtlich der Ausführungsgeometrien des Prozessgaszuführungs- und Brennerkühlsystems genutzt. Im Rahmen des erarbeiteten thermomechanischen Simulationsmodells wurden die beim Plasma-Auftragschweißen von Verbundbauteilen auftretenden Temperaturfelder, Verformungen und Eigenspannungen vorausbestimmt, untersucht und analysiert. Mittels des erarbeiteten Simulationsmodells wurden werkstoffliche, konstruktive und fertigungstechnische Maßnahmen zur Minimierung/Beeinflussung schweißbedingter Verformungen und Eigenspannungen simulativ untersucht und bewertet. / In this work, technical and constructive solutions were developed based on simulation models (process and structural) for fluid mechanical, thermomechanical and magneto-hydrodynamic effects. The simulation process included improving and characterising the physical operating principles for micro plasma welding, high performance plasma welding and orbital plasma welding. Also, the physical effects for the above plasma welding processes were studied and analysed. From these different physical properties of the parameters for the plasma welding processes, and their effects on plasma welding process behaviour and torch design were analysed and characterised. The results were used for the development and construction of plasma welding torch models, which included material selection and geometrical design such as, process gas supply design, torch cooling system design, and other related torch designs. By developing the thermomechanical simulation model, deformations and residual stresses that were generated by heating during the plasma welding process were investigated and analysed. The developed thermomechanical model included material, structural and welding specifications such as buffering and preheating. Simulations utilizing this model were used in order to reduce the residual stresses and deformations of the welded components.

- An Plasmaschweißbrennern treten starke thermomechanische Beanspruchungen aufgrund der ablaufenden thermophysikalischen Teilprozesse auf. Diese können durch funktionsgerechte werkstoffliche, konstruktive und fertigungstechnische Brennergestaltung bewerkstelligt und die Thermobilanz und Lebensdauer der Brenner verbessert werden. - Anhand des entwickelten strömungs-thermomechanischen/magneto-hydro-dynamischen Simulationsmodells wurden werkstofflich-konstruktive Lösungsansätze für Entwicklung von physikalischen Prozesswirkprinzipien der betrachteten Plasma-Schweißprozessvarianten erarbeitet. - Differente Einflussgrößen des Plasmaschweißprozesses wurden erfasst, analysiert und ihre Wirkung auf Prozessverhalten und Brennerkonstruktion ermittelt. - Die damit gewonnenen Erkenntnisse wurden für werkstoffliche, technisch-konstruktive Brennerentwicklung bzgl. der Ausführungsgeometrien, Prozessgaszuführung und Brennerkühlung genutzt.

• Für eine exakte Lichtbogenpositionierung zum Schweißpunkt werden beim Roboter – WIG-Schweißprozess folgende technische Anforderungen am Brennerkopf und dessen Wechselsystem gestellt wie: konstante Wärmeableitung und -führung im Brennerkopfbereich, schnelle Wechsel von Verschleißteilen insbesondere der Kathode, reproduzierbare Wechsel der Schweißbrennerköpfe. • Entwicklung eines neuartigen physikalischen Wirkprinzips auf Basis der Wärmeableitung – Heatpiperohr zur Gestaltung einer optimierten Wärmebilanz und Brennerkopfkühlung. • Mit dem entwickelten thermo – strömungs-mechanischen/magneto-hydro-dynamischen FE-Modells wurde die technisch-konstruktive Brennerkonstruktion mit der integrierten Wärmeableitung – Heatpiperohr für ein äußerst effektives Brennerkühlsystem unter Variation der Schweißprozessparameter zur Erzielung einer höheren Brennerdauerbelastung prozesstechnisch untersucht, analysiert und erkenntnisbezogen optimiert. • Beeinflussbar sind Lichtbogenausbildung, dessen Intensität, Verhalten sowie Temperatur- und Strömungsverhältnisse durch Prozessparameter.