Dissertations / Theses on the topic 'Wet processes'

The main objective of this work was to test the efficiency of wet oxidation processes when treating several types of aqueous wastes. On one side its performance for the abatement of chloro-organic aromatic toxic pollutants, such as 4-chlorophenol and 2,4-dichlorophenol has been studied. On the other hand, wastewater from pulp and paper mills, which has been reported to be an indirect source of entry of chlorophenols in the aquatic environment, has been investigated. More in detail, it has been taken as feed stream for the wet oxidation unit in order to investigate whether this type of waste streams can be treated by this technology or not.

Regarding Chlorophenols, special attention was drawn to the degradation of 4-chlorophenol by means of wet oxidation and wet peroxide oxidation. This aromatic compound was taken into investigation due to its harmful properties against the environment and due to its wide presence in the environment. Once it was clear that it could be degraded by these technologies, a research focused on the influence of the operating conditions in the result of the oxidation was carried out. The influence on the wet peroxide oxidation and wet oxidation reactions of the following parameters, initial concentration of the pollutant, temperature and amount of oxidizing agent (oxygen or hydrogen peroxide depending on the process) has been taken under study.

The identification and quantification of the intermediate compounds involved in the wet oxidation of 4-chlorophenol, together with a suggested mechanistic pathway, allowed the obtaining of a kinetic model, which appeared to be a useful tool for the prediction of these compounds throughout the reactions. The evolution of the free chlorine released to the solution from the degraded chlorophenol was also a useful tool when determining the kinetic pathway of the reaction.

Another objective of the work comprised the investigation of the variations of the biodegradability of the samples during the process. The knowledge of evolution of this parameter during the wet oxidation was thought to be of major importance, since high biodegradability enhancements allow the combination of a wet oxidation unit with a biological post-treatment, which is an effective and inexpensive technology to couple the oxidation.

The establishment of a comparison between wet oxidation and the wet peroxide oxidation for the removal of 4-chlorophenol was investigated as well.

Concerning wastewaters from pulp and paper mills, debarking and termo-mechanical pulp process wastewater have been treated by wet oxidation. Both waters were concentrated before oxidation in order to favor the economy of the process. Debarking wastewater was concentrated by evaporation and pulp process water by nanofiltration. The influence of the operating conditions, such as temperature and partial pressure of oxygen, on the results achieved at the end of the wet oxidation were studied and evaluated in order to find the optimum working conditions for each type of wastewater. Special attention was drawn to the evolution of Lipophilic Wood Extractive Compounds throughout the reactions. In addition, kinetic models suggested in the literature were tested to find a suitable one, which allowed the prediction of for instance, the organic load, over the duration of the reactions.

Due to the fact that wet oxidation is more economically viable when the initial waste stream is highly concentrated, a final chapter dedicated to a emerging technique, i.e., membrane technology has been included in this thesis. An investigation regarding the parameters affecting its performance, as well as the general aspects of the process has been conducted.

Enhancing mineral processing techniques is a permanent challenge in the mineral and metal industry. Indeed to satisfy the requirements on the final product (metal) set by the consuming market, control is often applied on the mineral processing whose product, the ore concentrate, constitutes the input material of the extractive metallurgy. Therefore much attention is paid on mineral processing units and especially on concentration plants. As the ore size reduction procedure is the critical step of a concentrator, it turns out that controlling a grinding circuit is crucial since this stage accounts for almost 50 % of the total expenditure of the concentrator plant. Moreover, the product particle size from grinding stage influences the recovery rate of the valuable minerals as well as the volume of tailing discharge in the subsequent process.

The present thesis focuses on an industrial application, namely the Kolwezi concentrator (KZC) double closed-loop wet grinding circuit. As any industrial wet grinding process, this process offers complex and challenging control problems due to its configuration and to the requirements on the product characteristics. In particular, we are interested in the modelling of the process and in proposing a control strategy to maximize the product flow rate while meeting requirements on the product fineness and density.

A mathematical model of each component of the circuit is derived. Globally, the KZC grinding process is described by a dynamic nonlinear distributed parameter model. Within this model, we propose a mathematical description to exhibit the increase of the breakage efficiency in wet operating condition. In addition, a relationship is proposed to link the convection velocity to the feed ore rate for material transport within the mills.

All the individual models are identified from measurements taken under normal process operation or from data obtained through new specific experiments, notably using the G41 foaming as a tracer to determine material transport dynamics within the mills. This technique provides satisfactory results compared to previous studies.

Based on the modelling and the circuit configuration, both steady-state and dynamic simulators are developed. The simulation results are found to be in agreement with the experimental data. These simulation tools should allow operator training and they are used to analyse the system and to design the suitable control strategy.

As the KZC wet grinding process is a Multi-Input Multi-Output (MIMO) system, we propose a decentralized control scheme for its simplicity of implementation. To overcome all the control issues, a Double Internal Model Control (DIMC) scheme is proposed. This strategy is a feedforward-feedback structure based on the use of both a modified Disturbance Observer (DOB) and a Proportional-Integral Smith-Predictor (PI-SP). A duality between the DOB and PI-SP is demonstrated in design method. The latter is exploited to significantly simplify the design procedure. The designed decentralized controllers are validated in simulation on the process linearized model. A progressive implementation of the control strategy is proposed in the context of the KZC grinding circuit where instrumentation might not be obvious to acquire./

Améliorer les techniques de traitement de minerais est un défi permanent dans l'industrie des minéraux et des métaux. En effet, pour satisfaire aux exigences du produit fini (métal ) fixées par le marché de consommation, la commande automatique est souvent appliquée à l'usine du traitement de minerais dont le produit, le concentré, constitue la matière première de la métallurgie extractive. Une attention particulière est donc dévolue aux unités de traitement de minerais et en particulier aux concentrateurs. Comme le processus de réduction des dimensions granulométriques du minerai est l'étape critique d'un concentrateur, il s'avère que la commande d'un circuit de broyage est cruciale, car ce stade représente près de 50 % des dépenses totales de l' usine de concentration. De plus, la dimension granulométrique du produit de l'étape de broyage influe sur le taux de récupération des minéraux utiles ainsi que sur le volume des rejets du processus ultérieur.

La présente thèse porte sur une application industrielle, à savoir le concentrateur de Kolwezi (KZC qui est un circuit de broyage humide à double boucle fermée. Comme tout processus industriel de broyage humide, ce procédé présente une problématique de commande complexe et difficile en raison de sa configuration et des exigences relatives aux caractéristiques du produit. En particulier, nous nous intéressons à la modélisation de ce procédé et à proposer une stratégie adéquate de commande dans le but de maximiser le débit de production tout en respectant les exigences quant à la finesse et à la densité de la pulpe produite.

Un modèle mathématique de chaque composant du circuit a été déterminé. Globalement, le processus de broyage de KZC est décrit par un modèle dynamique non linéaire à paramètres distribués. Dans ce modèle, une description mathématique de l'augmentation de l'efficacité du broyage en milieu humide est proposée. En outre, nous avons proposé une relation liant la vitesse de convection au débit d'alimentation de minerais dans le modèle du transport de la matière à l'intérieur des broyeurs.

Tous les modèles mathématiques ont été identifiés à partir de mesures prises sur le procédé en fonctionnement d'équilibre stable ou à partir des données obtenues grâce à des nouvelles expériences spécifiques, notamment en utilisant le moussant G41 comme traceur pour déterminer la dynamique de transport de la matière dans les broyeurs. Cette technique a produit des résultats cohérents par rapport aux études antérieurs réalisées au moyen du traceur colorant ou radioactif.

Les simulateurs statique et dynamique ont été développés sur la base de la modélisation mathématique et de la configuration du circuit. Les résultats des simulations sont en accord avec les données expérimentales. Ces outils de simulation devraient permettre la formation des opérateurs et ont été utilisés pour analyser le système et concevoir la stratégie de commande la plus appropriée.

Comme le processus de broyage humide de KZC est un système à plusieurs grandeurs d'entrée et plusieurs grandeurs de sortie, nous avons proposé une structure de commande décentralisée en raison de sa simplicité de mise en œuvre .Afin de surmonter tous les problèmes de commande, un schéma de commande à double modèle interne (CDMI) est proposée. Cette stratégie est une structure à anticipation - rétroaction basée sur l'utilisation d'un observateur de perturbations (OBP) et d'un Prédicteur de Smith doté d'un régulateur Proportionnel-Intégral (PS-PI). Une dualité entre l'OBP et le PS-PI est démontrée dans la méthode de conception. Cette propriété est exploitée pour simplifier considérablement la procédure de conception. Les régulateurs décentralisés ainsi conçus sont validés en simulation sur le modèle linéarisé du procédé. Une mise en œuvre progressive de la stratégie de commande est proposée dans le contexte du circuit de broyage de KZC où l'instrumentation peut ne pas être évidente à acquérir.

Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished

The aim of this research is to develop a wet-chemical silvering method for a three-dimensional (3D) textile material made of polyethylene terephthalate (PET) to prevent and eliminate biological contaminants in drinking water and other liquid-containing systems. Three-dimensional textile fabrics are particularly well-suited as silvered disinfection materials in water systems, because they have 3D structures, pressure-elastic textile design, and provide large contact areas. Furthermore, water can easily be passed through the structure. The developed wet-chemical procedures are based on aminosilane, which consists of at least two amine groups and is well-suited to form a silver diamine complex. The silvered textile material was coated with cationic silver. After the chemical reduction, the cationic silver turns into metallic silver on the surface of PET spacer fabrics. The surface morphology of silver-coated spacer fabrics was analyzed and the uniform silver layer on the PET fiber surface was found. X-ray diffraction and energy-dispersive X-ray spectroscopy analysis spectrums showed that the silver was immobilized on the PET fiber surface. The layer thickness and the silver amount were also determined. The silvered spacer fabrics can be used in sealing and/or cooling water systems; therefore, the silver ion release in water was analyzed. Furthermore, textile physical tests for the measurement of breaking force and elongation were carried out. No significant change in breaking force and elongation was observed after silvering of PET spacer fabric.

As multistep, multilayer processing in semiconductor industry becomes more complex, the role of cleaning solutions and etching chemistries are becoming important in enhancing yield and in reducing defects. This thesis demonstrates successful formulations that exhibit copper and tungsten compatibility, and are capable of Inter Layer Dielectric (ILD) cleaning and selective Ti etching. The corrosion behavior of electrochemically deposited copper thin films in deareated and non-dearated cleaning solution containing hydrofluoric acid (HF) has been investigated. Potentiodynamic polarization experiments were carried out to determine active, active-passive, passive, and transpassive regions. Corrosion rates were calculated from tafel slopes. ICP-MS and potentiodynamic methods yielded comparable Cu dissolution rates. Interestingly, the presence of hydrogen peroxide in the cleaning solution led to more than an order of magnitude suppression of copper dissolution rate. We ascribe this phenomenon to the formation of interfacial CuO which dissolves at slower rate in dilute HF. A kinetic scheme involving cathodic reduction of oxygen and anodic oxidation of Cu0 and Cu+1 is proposed. It was determined that the reaction order kinetics is first order with respect to both HF and oxygen concentrations. The learnings from copper corrosion studies were leveraged to develop a wet etch/clean formulation for selective titanium etching. The introduction of titanium hard-mask (HM) for dual damascene patterning of copper interconnects created a unique application in selective wet etch chemistry. A formulation that addresses the selectivity requirements was not available and was developed during the course of this dissertation. This chemical formulation selectively strips Ti HM film and removes post plasma etch polymer/residue while suppressing the etch rate of tungsten, copper, silicon oxide, silicon carbide, silicon nitride, and carbon doped silicon oxide. Ti etching selectivity exceeding three orders of magnitude was realized. Surprisingly, it exploits the use of HF, a chemical well known for its SiO2 etching ability, along with a silicon precursor to protect SiO2. The ability to selectively etch the Ti HM without impacting key transistor/interconnect components has enabled advanced process technology nodes of today and beyond. This environmentally friendly formulation is now employed in production of advanced high-performance microprocessors and produced in a 3000 gallon reactor.

This thesis examines the particle capture, fibre wetting and droplet flow processes within wet filters collecting solid and liquid aerosols and within filters collecting only liquid aerosols. The processes involved in this type of filtration were examined through a series of experiments and models developed to describe the behaviour of fibre/liquid systems. This work can be summarized in 4 categories: (1) The bounce and immediate re-entrainment of liquid and solid monodisperse aerosols under a stable filtration regime (pre cake formation) by wet and dry fibrous filters. In this work it was found that the solid particles generally exhibited a lower fractional filtration efficiency than liquid particles (of the same size), although this difference decreased in the smaller size fractions. However, for the wet filtration regime (each fibre of the filter was coated by a film of water), no significant difference in filtration efficiency was detectable between solid and liquid aerosols. Either the bounce effect of the particles is inhibited by the liquid film, or the filtration conditions in the wet filter are so different that the aerosol properties are less significant with respect to capture. (2) A microscopic study of the effect of fibre orientation on the fibre wetting process and flow of liquid droplets along filter fibres when subjected to airflow and gravity forces was conducted. The flow of the liquid collected by the fibres was observed and measured using a specially developed micro-cell, detailed in the thesis. The experimental results were compared to a theoretical model developed to describe the flow of droplets on fibres. The theory and experimental results showed a good agreement. A sensitivity analysis of the model was performed which showed the droplet radius to be the most significant parameter. The model has the potential to improve filter self-cleaning and minimise water use. (3) An experimental study of the capture of solid and liquid (oil) aerosols on fibrous filters wetted with water. Variable quantities of liquid irrigation were used, and the possibility for subsequent fibre regeneration after clogging or drying was also studied. It was found that self-cleaning (removal of solid aerosols by water) occurred even under heavily dust-laden conditions, and post evaporation of water. With the collection of oil aerosols on fibres wetted with water, a predominance of the barrel shaped droplet on the fibre was observed, with oil droplets displacing water droplets (if the oil and fibre combination created a barrel shaped droplet), creating various compound droplets of oil and water not previously reported in literature. (4) An extensive experimental investigation of the wetting processes of fibre/liquid systems during air filtration (when drag and gravitational forces are acting) has shown many important features, including droplet extension, oscillatory motion, and detachment from fibres as airflow velocity increases. The droplet oscillation is believed to be induced by the onset of the transition from laminar to turbulent flow as droplet size increases. To model such oscillation it was necessary to create a new conceptual model to account for the forces both inducing and preventing such oscillation. The agreement between the model and experimental results is satisfactory for both the radial and transverse oscillations.

This thesis examines the particle capture, fibre wetting and droplet flow processes within wet filters collecting solid and liquid aerosols and within filters collecting only liquid aerosols. The processes involved in this type of filtration were examined through a series of experiments and models developed to describe the behaviour of fibre/liquid systems. This work can be summarized in 4 categories: (1) The bounce and immediate re-entrainment of liquid and solid monodisperse aerosols under a stable filtration regime (pre cake formation) by wet and dry fibrous filters. In this work it was found that the solid particles generally exhibited a lower fractional filtration efficiency than liquid particles (of the same size), although this difference decreased in the smaller size fractions. However, for the wet filtration regime (each fibre of the filter was coated by a film of water), no significant difference in filtration efficiency was detectable between solid and liquid aerosols. Either the bounce effect of the particles is inhibited by the liquid film, or the filtration conditions in the wet filter are so different that the aerosol properties are less significant with respect to capture. (2) A microscopic study of the effect of fibre orientation on the fibre wetting process and flow of liquid droplets along filter fibres when subjected to airflow and gravity forces was conducted. The flow of the liquid collected by the fibres was observed and measured using a specially developed micro-cell, detailed in the thesis. The experimental results were compared to a theoretical model developed to describe the flow of droplets on fibres. The theory and experimental results showed a good agreement. A sensitivity analysis of the model was performed which showed the droplet radius to be the most significant parameter. The model has the potential to improve filter self-cleaning and minimise water use. (3) An experimental study of the capture of solid and liquid (oil) aerosols on fibrous filters wetted with water. Variable quantities of liquid irrigation were used, and the possibility for subsequent fibre regeneration after clogging or drying was also studied. It was found that self-cleaning (removal of solid aerosols by water) occurred even under heavily dust-laden conditions, and post evaporation of water. With the collection of oil aerosols on fibres wetted with water, a predominance of the barrel shaped droplet on the fibre was observed, with oil droplets displacing water droplets (if the oil and fibre combination created a barrel shaped droplet), creating various compound droplets of oil and water not previously reported in literature. (4) An extensive experimental investigation of the wetting processes of fibre/liquid systems during air filtration (when drag and gravitational forces are acting) has shown many important features, including droplet extension, oscillatory motion, and detachment from fibres as airflow velocity increases. The droplet oscillation is believed to be induced by the onset of the transition from laminar to turbulent flow as droplet size increases. To model such oscillation it was necessary to create a new conceptual model to account for the forces both inducing and preventing such oscillation. The agreement between the model and experimental results is satisfactory for both the radial and transverse oscillations.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Environmental Engineering
Faculty of Environmental Sciences
Full Text

The arsenic maximum contaminant level (MCL) for drinking water is likely to be lowered sometime in 2001 or 2002. If the MCL is lowered, it is speculated that there will be stricter limits imposed on the disposal and handling of arsenic-containing residuals. The purpose of this study is to determine the properties of drinking water residuals, including the chemical characteristics, the amount of arsenic that leaches in common residual handling and dewatering processes, and the hazardous potential of the residuals. Residual samples were collected from seven utilities with high arsenic concentrations in their raw water. Included in the study were four plants that coagulate with ferric chloride, two with aluminum hydroxide, and one softening plant. The residuals from each facility were acid digested and chemically characterized using ICP-AES to determine the total arsenic, aluminum and iron present. TCLP and California WET were performed to verify if the residuals were hazardous. Simulated lagoons were set up and monitored over a six-month period to determine the amount of arsenic that was leached to the liquid portion over time. Toxicity testing was performed on the residuals at 20% and 100% after two months and six months of storage. Bench-scale sand drying beds were used to dewater residuals, and the leachates were analyzed to determine if arsenic leached from residuals. The residuals were found to contain high levels of arsenic during the chemical characterization. However, all of the facilities passed the current TCLP limit of 5 mg/L. For all residuals, the California WET values were much higher than the TCLP values. In the lagoon study, redox potentials decreased and the arsenic and iron concentrations in the liquid portions increased. In the sand drying beds, very little arsenic leached; arsenic concentrations in the leachate were less than 10 ppb. Lagoon storage may not be a safe alternative for residuals containing arsenic. However, sand drying does not appear to present any threats. There were differences between the toxicity tests performed at 100% solids and 20% solids in the lagoon study. Some of the values increased and others decreased. Additionally, toxicity testing conducted after lagoon aging differed from earlier toxicity testing, due to the changing soluble arsenic. These discrepancies suggest that the test results can be affected by the percent solids and age of the residuals, and specific instructions should be given for consistent residuals testing.
Master of Science

Pressure drop and void fraction are important hydro-dynamic aspects for wet gas metering. Among differential pressure drop meters, Venturi meters are the most favoured devices for measuring unprocessed wet gas flows. However, Venturi meters are based on dry gas metering concepts, and various correlation factors have to be applied to the readings, Because the correction factors are flow-regime-dependent and only valid within specified operating flow conditions (preferably homogeneous or quasi-homogeneous flows), preconditioning or mixing devices are required. Electrical capacitance tomography (ECT) has been applied to measure wet gas separation processes. A combination of Venturi and ECT present the strengths of both principles and overcome the respective disadvantages. The combination also gives a possibility for wet gas pressure gradient calculation using void fraction measurement from ECT.

[EN] The main topic of the present thesis is the improvement of fabrication processes simulation by means of the Level Set (LS) method. The LS is a mathematical approach used for evolving fronts according to a motion defined by certain laws. The main advantage of this method is that the front is embedded inside a higher dimensional function such that updating this function instead of directly the front itself enables a trivial handling of complex situations like the splitting or coalescing of multiple fronts. In particular, this document is focused on wet and dry etching processes, which are widely used in the micromachining process of Micro-Electro-Mechanical Systems (MEMS). A MEMS is a system formed by mechanical elements, sensors, actuators, and electronics. These devices have gained a lot of popularity in last decades and are employed in several industry fields such as automotive security, motion sensors, and smartphones. Wet etching process consists in removing selectively substrate material (e.g. silicon or quartz) with a liquid solution in order to form a certain structure. This is a complex process since the result of a particular experiment depends on many factors, such as crystallographic structure of the material, etchant solution or its temperature. Similarly, dry etching processes are used for removing substrate material, however, gaseous substances are employed in the etching stage. In both cases, the usage of a simulator capable of predicting accurately the result of a certain experiment would imply a significant reduction of design time and costs. There exist a few LS-based wet etching simulators but they have many limitations and they have never been validated with real experiments. On the other hand, atomistic models are currently considered the most advanced simulators. Nevertheless, atomistic simulators present some drawbacks like the requirement of a prior calibration process in order to use the experimental data. Additionally, a lot of effort must be invested to create an atomistic model for simulating the etching process of substrate materials with different atomistic structures. Furthermore, the final result is always formed by unconnected atoms, which makes difficult a proper visualization and understanding of complex structures, thus, usually an additional visualization technique must be employed. For its part, dry etching simulators usually employ an explicit representation technique to evolve the surface being etched according to etching models. This strategy can produce unrealistic results, specially in complex situations like the interaction of multiple surfaces. Despite some models that use implicit representation have been published, they have never been directly compared with real experiments and computational performance of the implementations have not been properly analysed. The commented limitations are addressed in the various chapters of the present thesis, producing the following contributions: - An efficient LS implementation in order to improve the visual representation of atomistic wet etching simulators. This implementation produces continuous surfaces from atomistic results. - Definition of a new LS-based model which can directly use experimental data of many etchant solutions (such as KOH, TMAH, NH4HF2, and IPA and Triton additives) to simulate wet etching processes of various substrate materials (e.g. silicon and quartz). - Validation of the developed wet etching simulator by comparing it to experimental and atomistic simulator results. - Implementation of a LS-based tool which evolves the surface being etched according to dry etching models in order to enable the simulation of complex processes. This implementation is also validated experimentally. - Acceleration of the developed wet and dry etching simulators by using Graphics Processing Units (GPUs).
[ES] El tema principal de la presente tesis consiste en mejorar la simulación de los procesos de fabricación utilizando el método Level Set (LS). El LS es una técnica matemática utilizada para la evolución de frentes según un movimiento definido por unas leyes. La principal ventaja de este método es que el frente está embebido dentro de una función definida en una dimensión superior. Actualizar dicha función en lugar del propio frente permite tratar de forma trivial situaciones complejas como la separación o la colisión de diversos frentes. En concreto, este documento se centra en los procesos de atacado húmedo y seco, los cuales son ampliamente utilizados en el proceso de fabricación de Sistemas Micro-Electro-Mecánicos (MEMS, de sus siglas en inglés). Un MEMS es un sistema formado por elementos mecánicos, sensores, actuadores y electrónica. Estos dispositivos hoy en día son utilizados en muchos campos de la industria como la seguridad automovilística, sensores de movimiento y teléfonos inteligentes. El proceso de atacado húmedo consiste en eliminar de forma selectiva el material del sustrato (por ejemplo, silicio o cuarzo) con una solución líquida con el fin de formar una estructura específica. Éste es un proceso complejo pues el resultado depende de muchos factores, tales como la estructura cristalográfica del material, la solución atacante o su temperatura. De forma similar, los procesos de atacado seco son utilizados para eliminar el material del sustrato, sin embargo, se utilizan sustancias gaseosas en la fase de atacado. En ambos casos, la utilización de un simulador capaz de predecir de forma precisa el resultado de un experimento concreto implicaría una reducción significativa del tiempo de diseño y de los costes. Existen unos pocos simuladores del proceso de atacado húmedo basados en el método LS, no obstante tienen muchas limitaciones y nunca han sido validados con experimentos reales. Por otro lado, los simuladores atomísticos son hoy en día considerados los simuladores más avanzados pero tienen algunos inconvenientes como la necesidad de un proceso de calibración previo para poder utilizar los datos experimentales. Además, debe invertirse mucho esfuerzo para crear un modelo atomístico para la simulación de materiales de sustrato con distintas estructuras atomísticas. Asimismo, el resultado final siempre está formado por átomos inconexos que dificultan una correcta visualización y un correcto entendimiento de aquellas estructuras complejas, por tanto, normalmente debe emplearse una técnica adicional para la visualización de dichos resultados. Por su parte, los simuladores del proceso de atacado seco normalmente utilizan técnicas de representación explícita para evolucionar, según los modelos de atacado, la superficie que está siendo atacada. Esta técnica puede producir resultados poco realistas, sobre todo en situaciones complejas como la interacción de múltiples superficies. A pesar de que unos pocos modelos son capaces de solventar estos problemas, nunca han sido comparados con experimentos reales ni el rendimiento computacional de las correspondientes implementaciones ha sido adecuadamente analizado. Las expuestas limitaciones son abordadas en la presente tesis y se han producido las siguientes contribuciones: - Implementación eficiente del método LS para mejorar la representación visual de los simuladores atomísticos del proceso de atacado húmedo. - Definición de un nuevo modelo basado en el LS que pueda usar directamente los datos experimentales de muchos atacantes para simular el proceso de atacado húmedo de diversos materiales de sustrato. - Validación del simulador comparándolo con resultados experimentales y con los de simuladores atomísticos. - Implementación de una herramienta basada en el método LS que evolucione la superficie que está siendo atacada según los modelos de atacado seco para habilitar la simulación de procesos comple
[CAT] El tema principal de la present tesi consisteix en millorar la simulació de processos de fabricació mitjançant el mètode Level Set (LS). El LS és una tècnica matemàtica utilitzada per a l'evolució de fronts segons un moviment definit per unes lleis en concret. El principal avantatge d'aquest mètode és que el front està embegut dins d'una funció definida en una dimensió superior. D'aquesta forma, actualitzar la dita funció en lloc del propi front, permet tractar de forma trivial situacions complexes com la separació o la col·lisió de diversos fronts. En concret, aquest document es centra en els processos d'atacat humit i sec, els quals són àmpliament utilitzats en el procés de fabricació de Sistemes Micro-Electro-Mecànics (MEMS, de les sigles en anglès). Un MEMS és un sistema format per elements mecànics, sensors, actuadors i electrònica. Aquests dispositius han guanyat molta popularitat en les últimes dècades i són utilitzats en molts camps de la indústria, com la seguretat automobilística, sensors de moviment i telèfons intel·ligents. El procés d'atacat humit consisteix en eliminar de forma selectiva el material del substrat (per exemple, silici o quars) amb una solució líquida, amb la finalitat de formar una estructura específica. Aquest és un procés complex ja que el resultat de un determinat experiment depèn de molts factors, com l'estructura cristal·logràfica del material, la solució atacant o la seva temperatura. De manera similar, els processos d'atacat sec son utilitzats per a eliminar el material del substrat, no obstant, s'utilitzen substàncies gasoses en la fase d'atacat. En ambdós casos, la utilització d'un simulador capaç de predir de forma precisa el resultat d'un experiment en concret implicaria una reducció significativa del temps de disseny i dels costos. Existeixen uns pocs simuladors del procés d'atacat humit basats en el mètode LS, no obstant tenen moltes limitacions i mai han sigut validats amb experiments reals. Per la seva part, els simuladors atomístics tenen alguns inconvenients com la necessitat d'un procés de calibratge previ per a poder utilitzar les dades experimentals. A més, deu invertir-se molt d'esforç per crear un model atomístic per a la simulació de materials de substrat amb diferents estructures atomístiques. Així mateix, el resultat final sempre està format per àtoms inconnexos que dificulten una correcta visualització i un correcte enteniment d'aquelles estructures complexes, per tant, normalment deu emprar-se una tècnica addicional per a la visualització d'aquests resultats. D'altra banda, els simuladors del procés d'atacat sec normalment utilitzen tècniques de representació explícita per evolucionar, segons els models d'atacat, la superfície que està sent atacada. Aquesta tècnica pot introduir resultats poc realistes, sobretot en situacions complexes com per exemple la interacció de múltiples superfícies. A pesar que uns pocs models son capaços de resoldre aquests problemes, mai han sigut comparats amb experiments reals ni tampoc el rendiment computacional de les corresponents implementacions ha sigut adequadament analitzat. Les exposades limitacions son abordades en els diferents capítols de la present tesi i s'han produït les següents contribucions: - Implementació eficient del mètode LS per millorar la representació visual dels simuladors atomístics del procés d'atacat humit. - Definició d'un nou model basat en el mètode LS que puga utilitzar directament les dades experimentals de molts atacants per a simular el procés d'atacat humit de diversos materials de substrat. - Validació del simulador d'atacat humit desenvolupat comparant-lo amb resultats experimentals i amb els de simuladors atomístics. - Implementació d'una ferramenta basada en el mètode LS que evolucione la superfície que està sent atacada segons els models d'atacat sec per, d'aquesta forma, habilitar la simulació de processo
Montoliu Álvaro, C. (2015). Study, Modelling and Implementation of the Level Set Method Used in Micromachining Processes [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/58609
TESIS

Hydrothermal. oxidation processes at high pressure and temperature can be operated at conditions below or above the critical point of water (374.2'C and 221 bar). The former, is known as Wet Air Oxidation (WAO) and the latter is often referred to as Supercritical Water Oxidation (SCWO). The researchp resentedin this thesisa imed at investigatingt he viability of SCWO and WAO in treating 1,8- diazabicyclo [5.4.0] undec-7-ene (DBU)-containing wastewaterp roducedf rom pharmaceuticaal pplications.D BU was selecteda s a recalcitrant nitrogenous compound of industrial interest, which is difficult to treat by conventional treatmentm ethodso f industrial wastewatersI.n principle, the two processesc an be regarded to a certaine xtenta s the samep rocessw ith the main differenceb eing the conditionso f water. Among many other implications( will be discussedin the thesis),t his resultsi n the existence of two phasesin the subcriticalr angew hile it is monophasica t the supercriticalr ange. In SCWO, a laboratory scale system consisting of a plug-reactor was employed for acquisition of novel kinetic data in the supercritical region by investigating the effect of several operating parameters namely temperature, pressure, oxidant-to-organic ratio, organic concentration and residence time. The possible reactions by-products were also investigated by following the fates of carbon and nitrogen at various reaction conditions. A laboratorys cales emi-batchs ystemc onsistingo f a stirredt ank reactorw as employedf or the WAO studies to obtain novel kinetic data of the destruction of DBU in the subcritical region. The investigation was focused on the effect of reaction temperature, pressure, organic concentration and the speed of impeller. No studies on oxidant-to-organic ratio were undertakena s the systemo peratedin vast excesso f oxidant. The kinetic data acquired in both sub- and supercritical systems were consequently incorporatedin the semi-batcha nd continuousr eactore quationsfo r WAO and SCWO system respectively to develop kinetic rate expressions for both processes. It was found that the global rate expressions uccessfullyd escribedt he kinetics of SCWO in a plug flow continuous reactor, while the WAO semi-batch process was modelled by the pseudo-first order expression. Complete organic carbon removal was achieved in the SCWO system, but incomplete removal was observed in the WAO system even at extreme operation conditions. Significant proportion of nitrogen component from the waste was converted to ammonia rather than nitrogen gas.

This thesis considers the fruit of the tara tree (Caesalpinia spinosa) as a sustainable source for tanning agents and proposes alternatives to the commercial mineral salts and vegetable extracts to comply with an increasing demand that concerns lower carbon footprint and health safety. Taxonomy of the tree is described and the substances contained in the fruit are chemically characterized in order to justify that tara farm forestry is economically viable and to secure a potential worth. The value chain is fully described from fruit collection in remote Andean regions to the export for the most important leather markets. Although tara tannins have been used in the leather industry and its properties being well known, the experimental part of the work aims to optimize innovative formulations using tara as wet-white pre-tanning agent. Combinations with a selected syntan used for wet white and final article recipes are proposed
Esta tesis considera el fruto del árbol de tara (Caesalpinia spinosa) como fuente sostenible de taninos para la curtición del cuero y propone alternativas para las sales minerales y los extractos vegetales como respuesta a la creciente demanda para reducir el impacto medioambiental y la seguridad de los artículos de consumo. Se describe la taxonomía del árbol así como la caracterización de su fruto para justificar la silvicultura como práctica económicamente viable y asegurar su valor y la cadena desde la recolección de los frutos en las regiones andinas hasta la exportación a los mercados más importantes de la industria del cuero. Aunque los taninos de la tara ya se usan para la fabricación de cueros desde épocas remotas y sus propiedades están reconocidas, la sección experimental de este trabajo se orienta a optimizar fórmulas innovadoras utilizando la tara como agente de curtido wet-white. Se proponen fórmulas para artículos finales.

The research contained in this thesis addresses a major industry-threatening problem where a complete change in methodology and technology was required to replace simple manual methodology developed more than fifty years ago. The problem was solved by the implementation of a high risk and complex high technology project in two phases. The thesis describes how research into the fundamental techniques available was utilised to develop the solution following the acquisition of the knowledge required to apply the techniques in a systematic manner. An holistic study of the inbound supply chain and conversion process was necessary to achieve the depth of process change needed. It was required to achieve a step change in the now unsafe working practices that had developed over the years since the start of the wet cast industry in the Cotswolds. Starting with an ergonomic study that uncovered the priority areas for automation, the study called on the use of a wide range of research techniques from: brainstorming; structured interviews; process mapping; to the invention and innovation associated with the introduction of leading edge technology combining linear motion devices with robots and introducing emerging radio frequency identification technology to initiate product changeovers. Radio data systems were used to introduce lean, Just-in-Time (JIT) concepts to the inbound supply chain By embarking on a review of the key techniques required to achieve success, each was evaluated to enable decisions to be made on their application to the prime objective of completing an automation project that eliminated health and safety issues and achieved a major reduction in conversion costs. The major cultural change required from the existing workforce was recognised at an early stage and the thesis describes the steps that were taken to minimise the impacts of inevitable job losses and social changes required to operate an automated plant over 24 hours without stopping for breaks. With a long history of operating only dayshifts, with occasional nightshifts in peak season, it was necessary to implement a new and unique shift operating system with variable shift lengths over the year to coincide with peak and low seasons. Mitigating the harmful effects from operating rotating shift systems was researched and a strategy for the `Social Project' running in parallel with the `Technology Project' was produced. Information associated with the social changes involved was completely transparent with full consultation taking place with the workforce and the trade union representing them. The social project underpinned the high-tech project to create the success achieved from the study. High-tech complex projects are known to carry a high degree of risk associated with them. In order to combat these risks it was necessary to apply a whole range of risk management techniques and to consider risk in an holistic manner. Incorporating financial, environmental, safety and completion time risks in the risk assessment/mitigation procedures applied. Many projects include the application of risk assessment and mitigation procedures before the project starts but few employ them in the dynamic manner over all phases of the project advocated in the thesis. The evaluation of the study outcome suggests further areas of risk management improvement to aid in the execution of further projects of the nature described in the thesis. A key element in the success of the automation project was the development of a detailed specification of the Phase 2 full automation project. This was possible after completion of the smaller Phase I project and was responsible for achieving the high degree of certainty demonstrated during the execution of the second phase. Having the opportunity of devising the automation innovation from first principles using prototype development techniques helped enormously in creating the new paradigm in wet cast manufacturing processes which eliminated the major health and safety issues and produced cost savings that enabled the company to compete successfully against low-cost Far Eastern imported products.

Doutoramento em Ciências e Engenharia do Ambiente
During the last decades a significant number of studies was performed about the cycling of carbonaceous matter in the atmosphere. Despite the efforts of the scientific community, a full understanding about the composition and formation of carbonaceous aerosol in ambient air was not yet achieved, reflecting the great variety of emitting sources and the complexity of transformation processes in the atmosphere. In addition, very little is known about a specific type of carbonaceous aerosol: the indoor carbonaceous aerosol. Removal of particulate carbonaceous matter from the atmosphere is another component of the carbon cycle that has received poor attention from researchers. The main aim of this work was to contribute to a better understanding of the sources, transformation processes and removal of atmospheric carbonaceous matter. Particulate matter, organic carbon (OC) and elemental carbon (EC) concentrations were measured simultaneously in the indoor and outdoor air of residences located in urban and sub-urban areas of northwestern Mainland Portugal. Average indoor to outdoor ratios (I/O) for OC were higher than 1 in occupied residences, showing that indoor sources, such as cooking, smoking, biomass burning and movement of people, strongly influenced indoor OC concentrations. In contrast, I/O ratios for EC were close to 1, except for a smokers’ residence, suggesting that indoor concentrations were mainly controlled by outdoor sources, most likely from vehicular emissions and biomass burning. Aerosol composition was also evaluated during one year in a kerbside site located in a busy road of Oporto. Road traffic, local dust and biomass burning were found to be the most important sources of aerosol particles. Most of the aerosol constituents exhibited well-defined temporal variations, which were related with the seasonal variability of source strengths, atmospheric processes and climatic conditions. In addition, precipitation samples were collected and characterized for chemical constituents at a background site in the Azores Islands and an urban site in the city of Oporto. Transport from continental areas bordering the North Atlantic Ocean were the main source of EC in the Azores. Both local emissions and long-range transport explained the levels of water soluble organic carbon found in the same samples. Concentrations of carbonaceous matter in Oporto were considerably higher than those measured before in other background areas in Portugal, indicating a significant atmospheric contamination by anthropogenic activities.
Nas últimas décadas foram desenvolvidos vários estudos sobre a circulação atmosférica da matéria carbonácea. Contudo, apesar dos esforços da comunidade científica, não se conseguiu ainda compreender detalhadamente a composição e a formação do aerossol carbonáceo no ar ambiente, o que reflete a grande variedade de fontes emissoras e a complexidade dos processos de transformação que ocorrem na atmosfera. Acresce ainda que se sabe muito pouco sobre um caso particular do aerossol de carbono: as partículas carbonáceas em suspensão no ar interior. Outra componente do ciclo do carbono que tem merecido pouca atenção da comunidade científica é a remoção das partículas carbonáceas da atmosfera. Este trabalho tem como objetivo principal contribuir para um melhor conhecimento sobre as fontes, processos de transformação e remoção da matéria carbonácea presente na atmosfera. As concentrações de matéria particulada, carbono orgânico (CO) e carbono elementar (CE) foram medidas simultaneamente no ar interior e exterior de residências localizadas em áreas urbanas e sub-urbanas da região nordeste de Portugal Continental. Os valores médios da razão entre as concentrações no ar interior e exterior (I/E) para o CO foram superiores a 1 para as residências com ocupantes, mostrando que as fontes interiores, como a confeção de alimentos, a queima de biomassa e o movimento de pessoas, influenciaram fortemente os teores de CO. Pelo contrário, obtiveram-se valores médios próximos de 1 para a razão I/E do CE, excluindo uma residência de fumadores, sugerindo que as concentrações deste componente eram controladas por fontes externas, muito provavelmente o tráfego automóvel e a queima de biomassa. A composição do aerossol foi também avaliada durante um ano num local confinante com uma estrada de tráfego intenso na cidade do Porto. Verificou-se que as principais fontes emissoras de partículas eram o tráfego automóvel, as poeiras do solo e a queima de biomassa. Muitos dos constituintes do aerossol mostraram variações temporais bem marcadas, as quais foram relacionadas com a variabilidade sazonal das fontes emissoras, dos processos atmosféricos e das condições climáticas. Procedeu-se ainda à recolha de amostras de precipitação e posterior caracterização química num local de fundo do arquipélago dos Açores e num local urbano da cidade do Porto. A principal fonte do CE nos Açores é o transporte a longas distâncias a partir das áreas continentais que envolvem o Atlântico Norte. Os teores de carbono orgânico insolúvel tiveram origem tanto em emissões locais como no transporte a longas distâncias. As concentrações de matéria carbonácea no Porto mostraram-se substancialmente superiores às que tinham sido medidas em áreas remotas de Portugal, indicando uma contaminação significativa por atividades antropogénicas.

Surface treatments are often used in the manufacturing industry to change the surface of a product, including its related properties and functions. The occurrence of degradation and corrosion in surface treatment processes can lead to critical breakdowns over time. Critical breakdowns may impair the properties of the products and shorten their service life, which causes increased lead times or additional costs in the form of rework or scrapping.  Prevention of critical breakdowns due to machine component failure requires a carefully selected maintenance policy. Predictive maintenance is used to anticipate equipment failures to allow for maintenance scheduling before component failure. Developing predictive maintenance policies for surface treatment processes is problematic due to the vast number of attributes to consider in modern surface treatment processes. The emergence of smart sensors and big data has led companies to pursue predictive maintenance. A company that strives for predictive maintenance of its surface treatment processes is Seco Tools in Fagersta. The purpose of this master's thesis has been to investigate the occurrence of critical breakdowns and failures in the machine components of the chemical vapor deposition and post-treatment wet blasting processes by mapping the interaction between its respective process variables and their impact on critical breakdowns. The work has been conducted as a Six Sigma project utilizing the problem-solving methodology DMAIC.  Critical breakdowns were investigated combining principal component analysis (PCA), computational fluid dynamics (CFD), and statistical process control (SPC) to create an understanding of the failures in both processes. For both processes, two predictive solutions were created: one short-term solution utilizing existing dashboards and one long-term solution utilizing a PCA model and an Orthogonal Partial Least Squares (OPLS) regression model for batch statistical process control (BSPC). The short-term solutions were verified and implemented during the master's thesis at Seco Tools. Recommendations were given for future implementation of the long-term solutions. In this thesis, insights are shared regarding the applicability of OPLS and Partial Least Squares (PLS) regression models for batch monitoring of the CVD process. We also demonstrate that the prediction of a certain critical breakdown, clogging of the aluminum generator in the CVD process, can be accomplished through the use of SPC. For the wet blasting process, a PCA methodology is suggested to be effective for visualizing breakdowns.

An extensive investigation with parallel field andlaboratory exposures has been conducted to elucidateatmospheric corrosion and metal runoff processes on copper andzinc used for roofing applications. Detailed studies have beenperformed to disclose the effect of various parameters on therunoff rate including: surface inclination and orientation,natural patination (age), patina composition, rain duration andvolume, rain pH, and length of dry periods inbetween rainevents. Annual and average corrosion rates and runoff rateshave been determined consecutively during urban field exposuresin Stockholm on naturally patinated copper and zinc of varyingage and patina composition. The corrosion rate was found todecrease with time, amounting to 6.7 g Cu/(m2.y) and 5.0 gZn/(m2.y) after 48 weeks of exposure, whereas the runoff ratewas relatively constant with time on a yearly basis, being 1.3g/(m2.y) and 3.1 g/(m2.y) for copper and zinc, respectively.The annual runoff rate was found to be significantly lower thanthe corresponding corrosion rate for both copper and zinc.Somewhat higher runoff rates of copper were determined fromnaturally green-patinated copper (>40 years old, 2.0g/(m2.y)) compared to brown-patinated copper (1 year old). Themain reasons are specific environmental conditions combinedwith characteristics of the patina layer, which increase themagnitude of dissolved species flushed from the surface duringthe first flush volume of a rain event. No intrinsic effect ofpanel age on the runoff rate was seen for naturally patinatedzinc. However, differences in prevailing environmentalconditions during the initial exposure period and, hence,differences in formation rate and surface coverage of thecorrosion patina, resulted in variations in runoff rate. Thisinitial difference remained also during prolonged exposureperiods and was referred to as a memory effect.

Model roof investigations and laboratory studies showedsurface orientation and inclination to have a detrimentaleffect on the runoff rate with high runoff rates from surfacesof low inclination from horizon and surfaces exposed towardsthe wind direction.

Based on fieldexposures and literature data, a correlationwas established between the runoff rate and the prevailingSO2-concentration. The runoff rate increases with increasingSO2 level for exposure sites of similar annual precipitationquantities (500-1000 mm/y). A rain device, using artificialrain, was shown to successfully simulate outdoor rain events ofvarying intensity and pH and result in realistic runoff ratesof both copper and zinc. The device was used to monitor changesin metal concentration and quantity of runoff water duringindividual rain events. High metal concentrations are found inthe initial rain volume flushing the surface (first flush),which decreased to rather constant metal concentrations duringthe subsequent rain volume (steady-state). The magnitude offirst flush depends primarily on environmental conditions priorto a rain event and the characteristics of the corrosionpatina. The metal concentration in runoff water increases withrain acidity, decreases with rain intensity and increases withlength of the dry period preceding a rain event.

A comparison between instantaneous corrosion rates,monitored by electrochemical impedance spectroscopy using a2-electrode set-up, and runoff rates during a continuous rainevent was performed for naturally patinated copper panels.Corrosion rates were found to be approximately 10 (brownishpatina) and 25 times (greenish patina) lower than correspondinginstantaneous runoff rates.

A schematic description of the first flush and steady-stateregion of the runoff process was established. The magnitude ofthe concentration during first flush is primarily affected byprevailing environmental conditions prior to a rain event,while rain pH and intensity primarily affect the concentrationduring steady-state.

Key words:atmospheric corrosion, corrosion rate, runoffrate, copper, zinc, field study, laboratory study, roof, firstflush, rain quantity, rain intensity, rain pH, dry and wetdeposition, corrosion and runoff process.

La liqueur noire, sous-produit de l’industrie papetière, est convertie par un processus hydrothermal. Elle a été choisie pour son contenu élevé en eau (80 wt%), matière organique (14 wt%) et minéraux (6 wt%) qui font d'elle une biomasse à haute valeur ajoutée bien qu'encore peu exploitée. L'étude en batch, balayant une large gamme de température (350°C-600°C), permet d'identifier deux flux sortant : une proportion d'hydrogène élevée dans la phase gazeuse (600°C), ainsi qu'une phase solide, appelée coke, générée quelques soient les conditions opératoires utilisées. La génération de solide modifie la composition du milieu réactionnel en procédé batch et peut poser problème en cas de transposition en réacteur continu. Il est donc important de comprendre sa formation pour pallier ces verrous. L'analyse du résidu montre qu'à 350°C, pour des temps de réaction courts (<2h), de microparticules carbonées se forment. Leur taille est influencée par les vitesses de montée et descente en température. Pour des températures plus hautes, le solide ne présente pas d'intérêt morphologique et sa proportion massique augmente avec la température. Ainsi, une production d'hydrogène significative s'accompagnera d'un dépôt solide dans le réacteur. Une étude catalytique a donc été menée en vue d'augmenter la quantité d'hydrogène et de diminuer la formation de coke tout en travaillant à plus basse température. Cette étude, menée à 350°C et 450°C, montre que les réactions d'hydrogénation et d'oxydation mises en jeu par le catalyseur conduisent aux résultats escomptés. La conversion de molécules modèles de la liqueur noire, menée dans les mêmes conditions d'expériences, a permis d'appréhender les mécanismes majeurs mises en jeu lors de la conversion hydrothermale. Les microparticules à 350°C peuvent être valorisées. Cependant, le changement de taille et de morphologie au cours du temps interroge sur la possibilité de passer en réacteur continu. La formation de solide peut être évitée à partir de 450°C en présence de catalyseur, favorisant en parallèle la production d'hydrogène. De ce fait, ce travail de thèse aborde les verrous scientifiques, techniques et technologiques liés à la conversion hydrothermale de la liqueur noire et notamment de la formation du solide, en présence ou non de catalyseur
Black liquor, a by-product of paper industry, is converted by hydrothermal process. It was chosen for its high water content (80 wt%), organic material (14 wt%) and minerals (6 wt%) that make it a high-value biomass while still untapped. The study in batch, screening a wide temperature range (350°C-600°C), used to identify two outgoing flows: a high proportion of hydrogen in the gas phase (600°C) and a solid phase, called coke, generated regardless the operating conditions used. The generation of solid changes the composition of the reaction medium in batch process and can be problematic in case of transposition in continuous reactor. Thus it is important to understand its formation to overcome these obstacles. Analysis of the residue shows that at 350°C, for short reaction times (< 2h), carbonaceous micro-particles are formed. Their size is influenced by the temperature rates of rise and fall. For higher temperatures, the solid is of no morphological interest and its weight proportion increased with temperature. Thus, a significant production of hydrogen will be associated with a solid deposit in the reactor. A catalytic study was conducted to increase the amount of hydrogen and reduce the formation of coke while working at lower temperature. This study, conducted at 350°C and 450°C, shows that hydrogenation and oxidation reactions involved with the catalyst, lead to the expected results. Converting models molecules of black liquor, conducted with the same experimental conditions, helped to understand the major mechanisms involved during the hydrothermal conversion. The micro-particles at 350°C can be valorized. However, the change in size and morphology over time wondered about the possibility of implement in continuous reactor. The solid formation can be prevented from 450°C in the presence of catalyst, favoring in parallel hydrogen production. Therefore, this thesis deals with scientific, technical and technological locks related to hydrothermal conversion of black liquor and especially the solid formation, with or without catalyst

A precipitação atmosférica é considerada um importante processo de remoção de poluentes da atmosfera. A caracterização química desta matriz ambiental pode indicar a presença de espécies inorgânicas proveniente de fontes naturais e antrópicas de uma determinada região. O presente trabalho foi realizado em três locais da Região Metropolitana de Porto Alegre (RMPA), no Sul do Brasil: Porto Alegre, Canoas e Sapucaia do Sul. Onde o crescimento das atividades urbano-industriais tem provocado um significativo aumento das emissões de poluentes para a atmosfera. A análise da caracterização química da precipitação úmida foi determinada por diferentes técnicas quantitativas: íons maiores por cromatografia iônica, elementos metálicos (Espectrometria de Emissão por Plasma - ICP/AES), razões isotópicas de Pb, Difratometria de Raios-X (DRX) e Microscopia Eletrônica de Varredura (MEV), com sistema EDS (Energy Dispersive Sistem). Além disso, foi realizado também um biomonitoramento com a espécie Lolium multiflorum Lam. Gramineae, somente para 2007, a fim de relacionar estes resultados com os dados dos parâmetros químicos da precipitação úmida da região estudada. Nesta parte do presente estudo foi selecionado um local controle, em Porto Alegre. Os resultados da integração dos dados do biomonitoramento com os dados de precipitação úmida mostraram que os íons Cl-, Na+, SO4 2-, NH4 + e Ca2+ apresentaram as maiores taxas de deposição, o que representou um elevado fator de enriquecimento para os íons Ca2+, K+ e SO4 2-. Os elementos metálicos Zn, Fe e Mn apresentam as maiores taxas de deposição na maioria dos meses estudados. Os parâmetros que avaliaram o biomonitoramento, atividade da enzima nitrato redutase, teor de enxofre e acúmulo de metais na área foliar da espécie Lolium multiflorum, mostraram-se mais significativos nas estações de amostragens Sapucaia e Canoas. A análise de cluster foi aplicada para integrar os resultados do biomonitoramento e da precipitação úmida, indicando a formação de dois agrupamentos distintos: Cluster 1 identificou os meses menos chuvosos e locais de exposição que não apresentaram valores elevados das variáveis analisadas, tanto no biomonitoramento como na precipitação úmida, incluindo a estação Porto Alegre/Controle. Entretanto, o cluster 2 caracterizou-se pela correlação entre os meses que mostraram as maiores taxas de pluviometria, o maior acúmulo de elementos metálicos e o mais elevado teor de enxofre na espécie de L. multiflorum, e as maiores taxas de deposição de elementos metálicos e íons maiores nas amostras de precipitação úmida da região estudada. A precipitação atmosférica de uma determinada região pode indicar alterações em bioindicadores acumulativos, principalmente para elementos metálicos, como a espécie L. multiflorum. Os resultados da composição química da precipitação úmida dos locais estudados, durante o período de 2005 a 2007, apresentaram como íons predominantes NH4 +, SO4 2- e Ca2+. O pH apresentou um valor médio de 5,97 +/- 0,5. Foram identificadas origens naturais e antrópicas na região estudada, através da aplicação de análises estatísticas multivariadas. Observam-se como fontes naturais aerossóis marinhos (Na+, Cl- e Mg2+) e partículas da crosta terrestre (Ca2+ e Mn). E a origem antrópica foi identificada pela presença de NO3 -, SO4 2-, NH4 +, Fe, Cu e Ni, e em menor proporção H+ e F- , proveniente de atividades industriais como refino de petróleo, siderurgia, fertilizantes, termoelétricas e também emissões veiculares. O predomínio da contribuição antrópica proveniente de emissões veiculares e de atividades siderúrgicas, presentes na região estudada, pode ser identificado pelas assinaturas isotópicas de 208Pb/207Pb e 206Pb/207Pb analisadas na precipitação úmida e material particulado suspenso da RMPA. Outra parte importante do presente trabalho foi à aplicação de modelos numéricos no estudo dos processos de remoção de SO4 2- que podem ocorrer dentro e abaixo da nuvem na região estudada. Foram aplicados dois modelos, o BRAMS (Brazilian Regional Atmospheric Modeling System) para simular a estrutura vertical das nuvens e o modelo de remoção B. V. 2 (Below-Cloud Beheng, versão 2) para calcular as concentrações de SO2 e SO4 2- que podem ocorrer na remoção úmida dentro (rainout) e abaixo da nuvem (washout). As concentrações de SO4 2- medidas experimentalmente na precipitação úmida e a concentração de SO2 no ar foram utilizadas como dados na modelagem. Os resultados modelados para a remoção de SO4 2- demostraram uma boa concordância (r=0,73) com os valores observados experimentalmente na precipitação úmida dos locais estudados. E também foi observada uma predominância dos processos de remoção que ocorrem dentro da nuvem como sendo os responsáveis por cerca de 70 a 90% da concentração de SO4 2- encontrada na água de chuva, sendo corroborados por dados encontrados na literatura.
The atmospheric precipitation is considered one of the most important scavenging processes of pollutants from the atmosphere. The chemical characterization of this environmental matrix may indicate the presence of inorganic species from natural and anthropogenic sources in a determined region. This study was conducted in three cities in the Metropolitan Area of Porto Alegre (MAPA), in southern Brazil: Porto Alegre, Canoas and Sapucaia do Sul. The growth of urban-industrial activities in this region has caused a significant increase in emissions of pollutants to the atmosphere. The analysis of the chemical characterization of wet precipitation was determined by different quantitative techniques: major ions by ion chromatography, metallic elements (by Inductively Coupled Plasma - ICP/AES), Pb stable isotope ratio, X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM), with EDS (Energy Dispersive System). Moreover, a biomonitoring with Lolium multiflorum Lam Gramineae species has been realized for 2007 in order to relate these results to data from chemical parameters of wet precipitation in the region studied. For this part of the study a control site was selected in Porto Alegre. The results of the integration of data from biomonitoring with wet precipitation data showed that the ions Cl-, Na+, SO4 2-, NH4 + and Ca2+ had the highest rates of deposition, which represented a high enrichment factor for the ions Ca2+, K+ and SO4 2-. The metallic elements Zn, Fe and Mn have the highest rates of deposition in most of the months studied. The parameters evaluating the biomonitoring, activity of the enzyme nitrate reductase, sulfur and accumulation of metals in leaf samplers of L. multiflorum, were more significant in the sampling stations Sapucaia and Canoas. The cluster analysis was applied to integrate the results of biomonitoring and wet precipitation, indicating the formation of two distinct groups: Cluster 1 identified the less rainy months and sites of exposure that did not show high values of variables, both in biomonitoring and in wet precipitation, including the station Porto Alegre/Control. However, the cluster 2 was characterized by the correlation between the months that showed the highest rates of rainfall, the largest accumulation of metallic elements and high sulfur content in the species of L. multiflorum, and higher deposition rates of metallic elements and major ions in samples of wet precipitation in the region studied. It was shown that the atmospheric precipitation in a region may indicate changes in accumulative bioindicators, especially for metallic elements, such as species L. multiflorum. The results of the chemical composition of wet precipitation at the studied sites during the period 2005 to 2007 presented as predominant ions NH4 +, SO4 2- and Ca 2+. The pH presented an average of 5.97 ± 0.5. Natural and anthropogenic sources in the studied region were identified by the application of multivariate statistical analysis. As natural sources from marine aerosols observes Na+, Cl- and Mg2+ as well as Ca2+ and Mn for soil of origin respectively. The anthropogenic sources were identified by the presence of NO3 -,SO4 2-, NH4 +, Fe, Cu and Ni and to a lesser extent H+ and F-, from industrial activities as oil refinery, steel production, fertilizers, coal-fired power plants and vehicular emissions. The dominance of the anthropogenic emissions from vehicles and industrial activities, present in the studied region, can be identified by the isotopic signatures of 208Pb/207Pb and 206Pb/207Pb analyzed in wet precipitation and suspended particulate material of the MAPA. Another essential part of this work is characterized by the application of numerical models in the study the scavenging processes of SO4 2- that can occur in-cloud and below-cloud in the region studied. Two models were applied: The BRAMS (Brazilian Regional Atmospheric Modeling System) to simulate cloud vertical structure and model B. V. 2 (Below-Cloud Beheng, version 2) to calculate the concentrations of SO2 and SO4 2- that occur in-cloud and below-cloud in the event of rainfall. The experimentally observed concentrations of SO4 2- in wet precipitation and concentration of SO2 in the air were used as modeling data. The modeled results for the removal of SO4 2- showed a good correlation (r = 0.73) with the experimentally observed values of wet precipitation in the studied sites. There was also a predominance of in-cloud scavenging processes responsible for about 70 to 90% of the concentration of sulfate in rainwater, corroborating data in the literature.

Le kesteriti sono una classe di semiconduttori con un band gap diretto compresa tra 1,0 e 1,5 eV e un coefficiente di assorbimento dell'ordine di 10^4 cm^ -1 nello spettro visibile e durante gli ultimi vent’anni hanno ricevuto parecchia attenzione a causa della loro potenziale applicabilità come materiali a film sottile nel fotovoltaico. Un altro calcogenuro a film sottile, il CIGS, di composizione Cu2InxGa (1-x)Se2 è già prodotto a livello industriale, ma il costante aumento del prezzo dell’ indio ha spinto la ricerca di materiali alternativi, come il CZTS(e), che sono composti solo da elementi abbondanti (quindi relativamente a buon mercato). Al fine di soddisfare per mezzo di fonti rinnovabili la crescente domanda di energia, non solo l’ abbondanza delle materie prime è un fattore chiave, ma anche i metodi scelti per la crescita di questi materiali devono essere attentamente valutati. I processi basati sul vuoto come la co-evaporazione e lo sputtering sono stati ampiamente utilizzati per la preparazione di strati assorbitori su scala di laboratorio. Tuttavia, questi metodi sono piuttosto complessi e comprendono costi di produzione elevati. I metodi a pressione ambiente (metodi chimici) sono caratterizzati da fasi di fabbricazione più semplici rispetto ai metodi in vuoto. In questa tesi sono state studiate tre diverse tecniche di deposizione chimiche: lo spin coating di una formulazione sol-gel, il drop-casting di una sospensione composta da complessi metallo-tiourea e blade coating d una soluzione concentrata contenente formiati. Per quanto riguarda il secondo metodo, è stata posta particolare attenzione sulla fattibilità di un metodo di deposizione attuato a temperature inferiori rispetto a quelle riportate in letteratura. Successivamente il focus è stato puntato sulla ottimizzazione dei parametri di processo in modo da regolare la reologia del strato assorbitore, ovvero la composizione del solvente, la velocità di riscaldamento e raffreddamento durante i trattamenti termici, la concentrazione tiourea e l'uso di un legante polimerico. Per quanto riguarda il terzo metodo, l'obiettivo era di sfruttare il potere riducente degli anioni formiato per ottenere precursori metallici. Ulteriori studi sono stati effettutati sugli effetti del doping di sodio sulla morfologia del CZTSe. Mediante analisi termogravimetrica accoppiata a spettrometria di massa è stato anche possibile descrivere parzialmente la chimica di formazione dello strato di film precursore. Per tutti i metodi presentati la qualità degli strati assobitori è stata valutata in termini di purezza di fase, compattezza del film risultante e le prestazioni dei dispositivi fotovoltaici. I film di CZTS(e) sono stati analizzati mediante microscopia elettronica a scansione,spettroscopia EDX, spettroscopia Raman, microscopia ottica e diffrazione di raggi X. I dispositivi sono stati caratterizzati con misure di corrente-tensione sotto illuminazione e misure di efficienza quantica esterna.
CZTS(e), often referred to as kesterites, are a class of semiconductors with a direct band gap ranging between 1.0 and 1.5 eV and an absorption coefficient in the order of 104 cm-1 in the visible spectrum, and during the last two decades they have been gaining a lot of attention because of their potential use as a thin film absorbers in photovoltaics. Another thin film chalcogenide, CIGS, with composition Cu2InxGa(1-x)Se2 has already reached the commercial production stage, but the constant increase of indium price has driven hunt to alternative materials, like Cu2ZnSn(S,Se)4, which are composed only of abundant (thus relatively cheap) elements. In order to meet the terawatt-scale power generation with photovoltaics, not only the abundancy of the raw materials is a key factor, but also the method chosen for growing these materials need to be carefully considered. The vacuum-based processes including co-evaporation and sputtering have been largely used for preparing absorber layers on a laboratory scale. However, these methods have drawbacks such as the complexity in process and high production costs. Non-vacuum chemical processes are characterized by simpler fabrication steps compared to vacuum-based methods. In this thesis, three new non-vacuum deposition techniques have been studied: -the spin-coating of a sol-gel, -the drop-casting of a suspension composed of thiourea-metal complexes -the blade-coating of a metal formates containing concentrated solution. For all the methods developed in this work, the quality of the resulting absorber layers is evaluated in terms of phase purity, compactness of the film and performance of the solar cells. The CZTS(e) layers were analysed by scanning electron microscopy, energy-dispersive spectroscopy, Raman spectroscopy, optical microscopy and x-ray diffractometry. The devices were characterized with current-voltage measurements under illumination and external quantum efficiency measurements. A particular focus was set on the feasibility of a deposition method at temperatures lower than the one normally used to growth CZTS (550 °C). The aim is to use flexible substrates like polyimide that cannot sustain temperature higher than 450 °C. Then the focus was shifted on the optimization of the process parameters, namely the solvent composition, the heating and cooling rates during thermal treatments, the concentration of the sulfur source and the use of a polymeric binder, in order to produce compact absorber layers,. A preliminary study of sodium addition to the liquid formulation showed beneficial effects on the microstructure of the absorber and on the performance of solar cells produced in this work. Only with absorbers grown via the first and third method we succeed in making working devices. In particular, with a CZTSe thin film (less than 700 nm thick) produced by depositing the ink composed of metal formates and a nitrogen-rich base plus a sodium source, the highest efficiency achieved for a solar cell was 3.1%. The Jsc (29.8 mAcm-2) extracted from the J-V curve under illumination matches with some much more efficient CZTSe cells reported in the literature, indicating a good quality of the absorber layer. The Voc and the Fill Factor were 260 mV and 41% respectively, showing this low-cost solution process is very promising for further studies.

A área de gerenciamento de processos de negócio apresenta-se ativa e tem recebido atenção tanto da comunidade de pesquisa como da indústria. Uma das principais preocupações nessa área é a escolha da melhor abordagem para modelagem e implementação de processos de negócio. Atualmente, organizações possuem processos de negócio com complexas estruturas que são reavaliados e ajustados com frequência, exigindo flexibilidade das linguagens para modelagem de processos. Além disso, processos de negócio atuais também exigem ambientes para implementação capazes de garantir confiabilidade na execução de instâncias do processo modelado, especialmente em caso de falhas. Embora diversos modelos transacionais tenham sido propostos com o objetivo de garantir propriedades transacionais adaptadas ao contexto de processos de negócio, a implementação de processos transacionais ainda oferece um cenário com desafios teóricos e práticos. Neste trabalho apresentamos uma implementação da abordagem WED-flow para controle de processos transacionais. A WED-flow é uma abordagem que combina conceitos de modelos transacionais avançados, eventos e estados de dados com o objetivo principal de reduzir a complexidade no tratamento de exceções. A ferramenta de software desenvolvida é capaz de controlar a execução de instâncias de processos de negócio, permite a evolução incremental do modelo projetado e ainda disponibiliza a estrutura necessária para apoiar a implementação de mecanismos de recuperação para tratar interrupções em instâncias causadas por exceções.
Business processes management is an active area which have received increased attention from research and industry communities. A major concern is the selection of the best approach for modeling and implementing business processes. Nowadays, organizations have business processes with complex structures, which are reevaluated and adjusted frequently, requiring flexibility from modeling languages. In addition, current business processes also require implementation environments capable of ensuring execution reliability, especially in case of failures. Although several transactional models have been proposed in order to guarantee transactional properties adapted to the context of business processes, the implementation of transactional processes still offers a scenario with several theoretical and practical challenges. In this work, we present an implementation of WED-flow approach for controlling transactional processes. WED-flow is an approach which combines the concepts of advanced transactional models, events and data states for the purpose of reducing exception handling complexity. The developed software tool is able of controlling the execution of business processes instances, allows incremental evolution of the designed model and also provides the necessary structure to support recovery mechanisms implementation to handle instances interruptions caused by exceptions.

Comprehending the role that formation processes play in the constitution of an archaeological site is fundamental for a more precise interpretation of the data collected in it. Concerning shipwreck sites, such processes possess certain peculiarities which must be taken into account in the archaeological research. However, that subject is not sufficiently developed in the literature, especially in Brazil. Hence, the present work aims at discussing principles that should be considered when studying archaeological formation processes which influence shipwreck sites. To this end, a bibliographical review is conducted, firstly with a general approach and, after that, addressing the processes that act specifically at shipwreck sites. This bibliographical review brings together several works about archaeological formation processes at shipwreck sites and lays down a foundation for the next chapters. Subsequently, an analysis of three case studies is performed. In this analysis, aspects such as the research goals, the comprehensiveness of the depositional periods which are addressed and which types of processes (natural and cultural) are considered. Such analysis, led us to conclude that the authors do not entirely exploit the potential that the investigation of archaeological formation processes of shipwreck sites offer when interpreting of the material culture. With the intention of offering elements to assist researches of that field, we propose a model for the study of formation processes of shipwreck sites. Initially, we present a division of the wreckage process in eight phases. In this division are included processes that act in the pre-deposition, deposition and post-deposition, as well as natural and cultural processes. Finally, we discuss principles that should be included in the study of formation processes of archaeological sites. These principles follow the same stages of which a research typically consists: planning, data collection, data analysis and publication of the results.
A compreensão do papel que os processos de formação desempenham na constituição de um sítio arqueológico é fundamental para uma interpretação mais precisa de dados nele coletados. Em se tratando de sítios de naufrágio, há algumas particularidades na forma em que tais processos atuam, as quais devem ser levadas em consideração nas pesquisas arqueológicas. Contudo, esse é um tema pouco explorado na literatura, principalmente no Brasil. Desta forma, o presente trabalho tem como objetivo discutir princípios que devem ser considerados em um estudo de processos de formação de sítios arqueológicos de naufrágio. Para tanto, faz-se uma revisão bibliográfica sobre o tema, inicialmente em um âmbito mais geral, e, na sequência, são abordados os processos que atuam especificamente nos sítios de naufrágio. Essa revisão bibliográfica reúne diversos trabalhos sobre a formação de sítios arqueológicos de naufrágio e serve como base para os capítulos seguintes. Em seguida é feita uma análise de três estudos realizados sobre processos de formação de sítios de naufrágio. Nessa análise, levam-se em conta aspectos como os objetivos da pesquisa, a abrangência dos períodos deposicionais abordados e os tipos de processos (naturais e culturais). A partir dela, constatou-se que seus autores não exploraram com totalidade o potencial que a investigação sobre formação de sítios de naufrágio oferece para a interpretação da cultura material. Com o intuito de oferecer elementos que auxiliem pesquisadores da área, propomos um modelo para o estudo dos processos de formação em sítios de naufrágio. Numa primeira parte fazemos uma divisão do processo de naufrágio em oito fases. Nessa divisão estão incluídos processos que atuam na pré-deposição, deposição e pós-deposição, assim como processos de origem natural e cultural. Por fim, são apresentados princípios que devem ser incluídos ao se estudar a formação de um sítio arqueológico de naufrágio. Esses princípios seguem a mesma divisão das etapas de uma pesquisa: planejamento, coleta de dados, análise dos dados e publicação dos resultados.

La composition isotopique de l’eau (dO18 et dD) est couramment utilisée pour étudier le cycle de l’eau actuel et passé ainsi que ses variations. Alors que dans les zones polaires, cet outil géochimique représente les fondements de la reconstitution des climats polaires passés, de multiples questions demeurent quant aux facteurs pilotant la composition isotopique de l’eau dans les tropiques.Afin de répondre à ces questions, le présent travail de thèse a porté sur la réalisation de mesures en continu de la composition isotopique de la vapeur d’eau sur l’île de La Réunion (océan Indien), ainsi que sur l’évaluation du potentiel de ces mesures pour la compréhension des processus atmosphériques humides prévalant sur cette zone géographique. L’implantation d’un spectromètre laser à l’Observatoire Atmosphérique du Maïdo nous a permis d’obtenir une chronique de trois ans de mesures.Dans un premier temps, les différentes variabilités temporelles que présentent nos mesures ont été étudiées. Les enregistrements ne montrent aucune cyclicité saisonnière sur la composition isotopique de la vapeur d’eau. Elles indiquent en revanche une forte cyclicité diurne, ainsi qu’une variabilité synoptique associée à des évènements cycloniques.Dans un second temps, nous montrons que cette cyclicité diurne résulte de phénomènes de mouvement de couche limite atmosphérique, avec une vapeur marine qui atteint l’Observatoire durant la journée, alors que des masses d’air en provenance de la troposphère libre y parviennent durant la nuit. La présence de certaines nuits significativement plus appauvries en dO18 et dD reflète (1) une modification de la circulation atmosphérique régionale avec un renforcement des subsidences au niveau de La Réunion, lié à la position du Jet Subtropical durant l’hiver austral, et (2) tantôt une intensification de la subsidence au niveau de La Réunion, tantôt des processus de condensation locaux ou régionaux durant l’été austral.Enfin, l’étude des phénomènes cycloniques indique qu’au cours de ces périodes, un fort appauvrissement de la composition isotopique de la vapeur est observé. Celui-ci survient 2 à 3 jours avant et perdure jusqu’à 3 jours après le passage du système. Durant cette période, l’évolution de la composition isotopique de la vapeur d’eau présente une sous-structure. On note (1) un appauvrissement isotopique qui est fonction de la distance au centre du système, (2) un enrichissement isotopique au niveau du mur du système, et (3) des évolutions abruptes de la composition isotopique de la vapeur d’eau dans les bandes précipitantes dues à des processus de mélange, de condensation et/ou de recharge
The isotopic composition of water vapor (dO18 and dD) is commonly used to study present and past water cycle and its varations. If this geochemical tool has been widely used to study past polar climates, many questions remain about the factors governing the isotopic composition of water in the tropics.The goal of this thesis is (1) to monitor the isotopic composition of water vapor in Reunion island (Indian Ocean), and (2) to evaluate the potential of theses measurements for understanding humid climate processes. We have set up a laser spectrometer at the Maïdo Atmospheric Observatory, allowing us to obtain a three-year chronicle of measurements.First, we analyze the temporal variability in our measurements. The isotopic composition of water vapor does not record any seasonal cyclicity. On the other hand, a strong diurnal cycle is visible, as well as a synoptic variability associated with cyclonic events.We then focus on the diurnal cycle. We show that it results from atmospheric boundary layer motions, with a marine vapor reaching the Observatory during the day, and air masses originating from the free troposphere reaching the Observatory during the night. During some nights, vapor is significantly more depleted in dO18 and dD. During the austral winter, this phenomenon is due to a modification of the regional atmospheric circulation causing a reinforcement of subsidences at Reunion Island, related to the position of the Subtropical Jet. During the austral summer, this phenomenon is sometimes due to an intensification of the subsidence at Reunion Island, and at other times to local or regional condensation processes.Finally, we focus on cyclonic events. During these periods, a strong isotopic depletion of the vapor is observed. We show that this depletion occurs 2 to 3 days before the system and continues until 3 days after. During this period, the evolution of the isotopic composition of the water vapor has a substructure. We note (1) an isotopic depletion that is a function of the distance to the center of the system, (2) an isotopic enrichment at the system wall, and (3) an abrupt evolutions of the isotopic composition of the water vapor in the rainbands due to mixing, condensation and/or recycling processes

In Web service composition, service discovery and combining suitable services through determination of interoperability among different services are important operations. Utilizing semantics improves the quality and facilitates automation of these operations. There are several previous approaches for semantic service discovery and service matching. In this work, we exploit and extend these semantic approaches in order to make Web service composition process more facilitated, less error prone and more automated. This work includes a service discovery and service interoperability checking technique which extends the previous semantic matching approaches. In addition to this, as a guidance system for the user, a new semantic domain model is proposed that captures semantic relations between concepts in various ontologies.

Die vorliegende Arbeit befasst sich mit der grundlegenden Untersuchung von Reaktionsmustern kristalliner Si-Oberflächen in HF-basierten Lösungen. Ausgehend von den industriell genutzten HF-HNO3-H2O-Gemischen wurden wisher wenig untersuchte HF/HNO3-Konzentrationsverhältnisse, die durch gelöste Stickoxide bedingten Folgereaktionen sowie der PH-Wert als Steuerparameter zur Aufarbeitung feinkörniger Si-Rohstoffe (Korngröße ≤ 0,5 mm) identifiziert. Die in diesem Kontext zentrale Rolle der NO+-Ionen wurde durch Untersuchung der spezifischen Reaktionsmuster an kristallinen as-cut und hydrophobierten Si-Oberflächen sowie bei Umsetzungen mit Oligosilanen als Modellverbindungen bestätigt. Die aus den umfassenden analytischen Daten (FT-IR-, Raman-, NMR-Spektroskopie, IC, REM-EDX, AFM) gewonnenen Erkenntnisse liefern einen wichtigen Beitrag zum Verständnis nasschemischer Halbleiterätzprozesse und erschließen neue Anwendungsfelder.

Die vorliegende Arbeit befasst sich mit der grundlegenden Untersuchung von Reaktionsmustern kristalliner Si-Oberflächen in HF-basierten Lösungen. Ausgehend von den industriell genutzten HF-HNO3-H2O-Gemischen wurden wisher wenig untersuchte HF/HNO3-Konzentrationsverhältnisse, die durch gelöste Stickoxide bedingten Folgereaktionen sowie der PH-Wert als Steuerparameter zur Aufarbeitung feinkörniger Si-Rohstoffe (Korngröße ≤ 0,5 mm) identifiziert. Die in diesem Kontext zentrale Rolle der NO+-Ionen wurde durch Untersuchung der spezifischen Reaktionsmuster an kristallinen as-cut und hydrophobierten Si-Oberflächen sowie bei Umsetzungen mit Oligosilanen als Modellverbindungen bestätigt. Die aus den umfassenden analytischen Daten (FT-IR-, Raman-, NMR-Spektroskopie, IC, REM-EDX, AFM) gewonnenen Erkenntnisse liefern einen wichtigen Beitrag zum Verständnis nasschemischer Halbleiterätzprozesse und erschließen neue Anwendungsfelder.

Num curto período de tempo, a Web tornou-se o aspecto central de muitas aplicações em diferentes áreas. Rapidamente, cresceu e diversificou seu uso, e diversos setores de negócio realizam suas operações no ambiente da Web. Entretanto, à medida que cresce a extensão de uso de aplicações Web, que se tornam mais complexas, aumenta a preocupação com a maneira como as aplicações são desenvolvidas. Freqüentemente, a abordagem de desenvolvimento é ad hoc, desprovida de técnicas sistemáticas e de metodologias sólidas, resultando em aplicações de baixa qualidade. A fim de alcançar aplicações Web bem sucedidas, há a necessidade de melhores princípios de esenvolvimento que devem considerar as características especiais dessas aplicações. Dessa forma, o objetivo do trabalho é propor Processos de Apoio ao desenvolvimento das aplicações Web, baseando-se nas características dessas aplicações e nos Processos de Apoio da ISO/IEC 12207. Os processos de Apoio visam auxiliar outros processos do ciclo de vida da aplicação a alcançar produtos de qualidade e o sucesso do projeto
Within a short period, the Web has become the central aspect of many applications in different areas. Rapidly, it has grown and diversified in its scope and use. Diverse business sectors improve their operations in Web environment. The Web application has become more complex and it has increased the concern with the way the application is developed. Frequently, the development is ad hoc, unprovide of systematic methods and methodologies, resulting in poor quality applications. In order to have successful Web applications, it is necessary better principles of development that have to consider the characteristics of these applications. The objective of this work is to propose Supporting Process for development Web applications, based on the characteristics of these applications and the Supporting Process of ISO/IEC 12207. The Supporting processes aim to assist other processes of the cycle of life of the application to reach quality products and successful projects

Le développement rapide du World Wide Web depuis les années 1990 a entraîné l'accroissement dunombre de sites web et l'intensification de la concurrence. Parallèlement, les moteurs de recherche ontjoué un rôle majeur en facilitant la recherche d'informations sur le web, au point de devenir une sourceinépuisable de trafic dont les propriétaires de sites web souhaitent profiter. Afin de capter un maximumde trafic qualifié, il est devenu nécessaire de se démarquer pour améliorer la visibilité d'un site web surles moteurs de recherche. Pour cela les propriétaires de sites web peuvent faire appel à des entreprisespratiquant le référencement web, et plus particulièrement le référencement naturel qui regroupel'ensemble des techniques d'optimisation permettant d'indexer et de positionner les pages d'un site webau plus haut niveau dans les résultats de recherche. L'activité de référencement web est conduite par leréférenceur qui, en optimisant un certain nombre de critères au sein du site web, améliore sonpositionnement. Mais les résultats obtenus sont incertains, car les algorithmes de classement desmoteurs de recherche sont en perpétuelle mutation. Dès lors, il est devenu nécessaire pour le référenceurd'avoir une meilleure maîtrise du processus de référencement web et d'être aidé dans ses prises dedécisions afin de satisfaire ses clients. Nos travaux de recherche ont permis d'apporter troiscontributions :- Établissement d'un cadre efficace pour l'activité de référencement à partir de la définition desdifférentes étapes du processus de référencement web en s'inspirant d'un méta-modèle d'ingénierie ;- Modélisation du processus de référencement web à partir d'un modèle d'agents afin de permettreune meilleure compréhension de son fonctionnement et de contrôler efficacement les différentesinteractions ;- Conception d'un système d'aide à la décision à partir de notre modèle d'agents servant desupport à l'activité de référencement web.Ces trois contributions majeures nous ont permis de répondre à notre problématique de recherche qui seproposait de répondre à la question suivante : « Comment concevoir le processus de référencement webpour améliorer sa maîtrise par le couple référenceur / client ? »
The World Wide Web has quickly grown since the 90s, and it has led to an increase in the number ofwebsites and the intensification of the competition. In parallel, search engines have played a major roleby facilitating the research of information on the web, to the point of being an infinite source of traffic ofwhich websites' owners would like to take advantage. In order to capture the maximum of qualifiedtraffic, it has become necessary to stand out from the competitors to improve the visibility of a websiteon search engines. To do that, websites' owners can resort to firms which practice Search EngineOptimization (SEO). The latter gathers all the optimization techniques which make it possible to improvethe ranking of web pages at the highest rank in the search results. The activity of search engineoptimization is done by a SEO practitioner who, by optimizing some technical criteria, improves theranking of the website. But the obtained results are uncertain, because of the ever-changing rankingalgorithms of search engines. Consequently, it has become necessary for the SEO practitioner to have abetter mastery of the SEO process and to be helped in its decision makings in order to satisfy its clients.Our research works have allowed us to make three contributions:- Creation of an efficient structure for the SEO activity from the definition of the different steps ofthe SEO process and the use of an engineering meta-model;- Modeling of the SEO process by using a multi-agent system in order to enable a betterunderstanding of its functioning and to efficiently master its different interactions;- Design of a decision support system thanks to our agent-based model to support the SEOa c t i v i t y .These three main contributions enabled us to answer our research question which was: "How to designthe search engine optimization process in order to improve its mastery by the SEO practitioner and theclient ?"

Las aplicaciones Web son consideradas actualmente un elemento esencial e indispensable en toda actividad empresarial, intercambio de información y motor de redes sociales. La usabilidad, en este tipo de aplicaciones, es reconocida como uno de los factores clave más importantes, puesto que la facilidad o dificultad que los usuarios experimentan con estas aplicaciones determinan en gran medida su éxito o fracaso. Sin embargo, existen varias limitaciones en las propuestas actuales de evaluación de usabilidad Web, tales como: el concepto de usabilidad sólo se soporta parcialmente, las evaluaciones de usabilidad se realizan principalmente cuando la aplicación Web se ha desarrollado, hay una carencia de guías sobre cómo integrar adecuadamente la usabilidad en el desarrollo Web, y también existe una carencia de métodos de evaluación de la usabilidad Web que hayan sido validados empíricamente. Además, la mayoría de los procesos de desarrollo Web no aprovechan los artefactos producidos en las fases de diseño. Estos artefactos software intermedios se utilizan principalmente para guiar a los desarrolladores y para documentar la aplicación Web, pero no para realizar evaluaciones de usabilidad. Dado que la trazabilidad entre estos artefactos y la aplicación Web final no está bien definida, la realización de evaluaciones de usabilidad de estos artefactos resulta difícil. Este problema se mitiga en el desarrollo Web dirigido por modelos (DWDM), donde los artefactos intermedios (modelos) que representan diferentes perspectivas de una aplicación Web, se utilizan en todas las etapas del proceso de desarrollo, y el código fuente final se genera automáticamente a partir estos modelos. Al tener en cuenta la trazabilidad entre estos modelos, la evaluación de estos modelos permite detectar problemas de usabilidad que experimentaran los usuarios finales de la aplicación Web final, y proveer recomendaciones para corregir estos problemas de usabilidad durante fases tempranas del proceso de desarrollo Web. Esta tesis tiene como objetivo, tratando las anteriores limitaciones detectadas, el proponer un método de inspección de usabilidad que se puede integrar en diferentes procesos de desarrollo Web dirigido por modelos. El método se compone de un modelo de usabilidad Web que descompone el concepto de usabilidad en sub-características, atributos y métricas genéricas, y un proceso de evaluación de usabilidad Web (WUEP), que proporciona directrices sobre cómo el modelo de usabilidad se puede utilizar para llevar a cabo evaluaciones específicas. Las métricas genéricas del modelo de usabilidad deben operacionalizarse con el fin de ser aplicables a los artefactos software de diferentes métodos de desarrollo Web y en diferentes niveles de abstracción, lo que permite evaluar la usabilidad en varias etapas del proceso de desarrollo Web, especialmente en las etapas tempranas. Tanto el modelo de usabilidad como el proceso de evaluación están alineados con la última norma ISO/IEC 25000 estándar para la evaluación de la calidad de productos de software (SQuaRE). El método de inspección de usabilidad propuesto (WUEP) se ha instanciado en dos procesos de desarrollo Web dirigido por modelos diferentes (OO-H y WebML) a fin de demostrar la factibilidad de nuestra propuesta. Además, WUEP fue validado empíricamente mediante la realización de una familia de experimentos en OO-H y un experimento controlado en WebML. El objetivo de nuestros estudios empíricos fue evaluar la efectividad, la eficiencia, facilidad de uso percibida y la satisfacción percibida de los participantes; cuando utilizaron WUEP en comparación con un método de inspección industrial ampliamente utilizado: La Evaluación Heurística (HE). El análisis estadístico y meta-análisis de los datos obtenidos por separado de cada experimento indicaron que WUEP es más eficaz y eficiente que HE en la detección de problemas de usabilidad. Los evaluadores también percibieron más satisfacción cuando se aplicaron WUEP, y les
Fernández Martínez, A. (2012). A Usability Inspection Method for Model-driven Web Development Processes [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/17845
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Com o intuito de tornarem-se mais eficientes, muitas organizações -- empresas, órgãos governamentais, centros de pesquisa, etc. -- optam pela utilização de ferramentas de software para apoiar a realização de seus processos. Uma opção que vem se tornando cada vez mais popular é a utilização de sistemas de Gestão de Processos de Negócio (GPN), que são ferramentas genéricas, ou seja, não são específicas a nenhuma organização, altamente configuráveis e ajustáveis às necessidades dos objetos de atuação de cada organização. Uma das principais responsabilidades de um sistema de GPN é prover mecanismos de tratamento de exceções à execução de instâncias de processos de negócio. Exceções, se forem ignoradas ou se não forem corretamente tratadas, podem causar o aborto da execução de instâncias e, dependendo da gravidade da situação, podem causar falhas em sistemas de GPN ou até mesmo em sistemas subjacentes (sistema operacional, sistema gerenciador de banco de dados, etc.). Sendo assim, mecanismos de tratamento de exceções têm por objetivo resolver a situação excepcional ou conter seus efeitos colaterais garantindo, ao menos, uma degradação controlada (graceful degradation) do sistema. Neste trabalho, estudamos algumas das principais deficiências de modelos atuais de tratamento de exceções, no contexto de sistemas de GPN, e apresentamos soluções baseadas em Modelos Transacionais Avançados para contorná-las. Isso é feito por meio do aprimoramento dos mecanismos de tratamento de exceções da abordagem de modelagem e gerenciamento de execução de processos de negócio WED-flow. Por fim, estendemos a ferramenta WED-tool, uma implementação da abordagem WED-flow, através do desenvolvimento de seu gerenciador de recuperação de falhas.
With the aim of becoming more efficient, many organizations -- companies, governmental entities, research centers, etc -- choose to use software tools for supporting the accomplishment of its processes. An option that becomes more popular is the usage of Business Process Management Systems (BPM), which are generic tools, that is, not specific to any organization and highly configurable to the domain needs of any organization. One of the main responsibilities of BPM Systems is to provide exception handling mechanisms for the execution of business process instances. Exceptions, if ignored or incorrectly handled, may induce the abortion of instance executions and, depending on the gravity of the situation, induce failures on BPM Systems or even on subjacent systems (operational system, database management systems, etc.). Thus, exception handling mechanisms aim to solve the exceptional situation or stopping its collateral effects by ensuring, at least, a graceful degradation to the system. In this work, we study some of the main deficiencies of present exception handling models -- in the context of BPM Systems -- and present solutions based on Advanced Transaction Models to bypass them. We do this through the improvement of exception handling mechanisms from WED-flow, a business process modelling and instance execution managing approach. Lastly, we extend the WED-tool, an implementation of WED-flow approach, through the development of its failure recovery manager.

Dynamic selection and composition of autonomous and loosely-coupled Web services is increasingly used to automate business processes. The typical long-running characteristic of business processes imposes new management challenges such as dynamic adaptation of running process instances. However, current process orchestration engines provide limited flexibility to dynamically adapt to changing runtime conditions (e.g., presence of faults). Additionally, current process specification languages exhibit some limitations regarding modularity of crosscutting management concerns. In particular, monitoring and adaptation logic is often scattered across several process definitions and intertwined with the business logic. This leads to monolithic and complex processes that are hard to understand, reuse, maintain, and evolve. To address these limitations, we developed a policy-based change management framework, named Manageable and Adaptable Service Compositions (MASC), to declaratively express crosscutting monitoring and process adaptation concerns in a separate and modular way. MASC policies use a set of simple, but flexible and relatively powerful, constructs to declaratively specify policies that govern: (1) discovery and selection of services to be used, (2) monitoring to detect the need for adaptation, (3) reconfiguration and adaptation of the process to handle special cases (e.g., context-dependant behaviour) and recover from typical faults in service-based processes. The identified constructs are executed by a lightweight service-oriented management middleware named MASC middleware. The adaptation is transparent because it preserves the original functional behaviour of the business process and does not tangle the adaptation logic with that of the business process. Additionally, policies do not have to be necessarily defined when designing the process; they can also be introduced later during deployment or at runtime. We implemented a MASC proof-of-concept prototype and evaluated it on Stock Trading case study scenarios. We conducted extensive studies to demonstrate the feasibility of the proposed techniques and illustrate the benefits of our approach in providing adaptive composite services using the policy-based approach. Our performance and scalability studies indicate that MASC middleware is scalable and the introduced overhead are acceptable.