This thesis represents an important contribution to facilitate the efficient creation of detailed inventories to carry out Life Cycle Assessment (LCA) studies of urban wastewater systems. Specifically, this thesis provides a tool to carry out an evaluation of the environmental impact of the construction of sewer systems. The work also shows that is necessary to consider the construction of wastewater treatment plants (WWTPs) when these studies are carried out and provides a set of useful linear regressions to calculate in a quickly and precise way the inventories for the civil works of small to medium WWTPs. Finally, the application of this methodology to evaluate the integrated management of different WWTPs is also presented together with an application of the water footprint in WWTPs to demonstrate that it can be also a valid tool to calculate its environmental impact. / Aquesta tesi representa una contribució important per facilitar la realització d'inventaris detallats per dur a terme estudis d'Anàlisi de Cicle de Vida (ACV) al sistema urbà d'aigua residual i que es poden obtenir d’una forma ràpida i amb resultats satisfactoris. Concretament, amb la tesi es presenta una eina per poder realitzar estudis d'impacte ambiental per la construcció de sistemes de col•lectors d'aigua residual. També demostra que cal tenir en compte la construcció de depuradores en aquest tipus d'estudis i també facilita una sèrie de regressions lineals útils per calcular de forma ràpida i precisa els inventaris per l’obra civil de depuradores d’una mida petita o mitjana. Finalment, també es presenta l'aplicació de la metodologia per avaluar la gestió integrada de diferents depuradores i l'aplicació de la petjada hídrica en depuradores per demostrar que també pot ser una eina molt vàlida per calcular d’una forma senzilla el seu impacte ambiental.

The energy demand increase and the generation of wastes is being the major problem regarding the next generation sustainability. Both problems can be corrected through the implementation of anaerobic digestion, a waste treatment technology able to produce electricity, heat and a fertilizer. The anaerobic co-digestion between two wastes with complementary characteristics has been widely studied to improve the methane production in anaerobic digesters. However, to increase the methane production from lignocelulosics substrates is still one of the main challenges of anaerobic digestion. Lignocelulosic components are a tridimensional structure between lignin, hemicellulose and cellulose, which bonds are extremely difficult to degrade by conventional anaerobic bacteria. Besides, those components can be found in a wide range of substrates such as municipal solid wastes, agro-wastes and energy crops. In the following thesis, the increase of the economic viability of anaerobic digestion plants treating lignocelulosic materials has been studied. Initially, the transitory state while the co-substrate was changed in the anaerobic co-digestion between sewage sludge and fruit waste was studied. The stability of the reactors was not drastically affected when the co-substrate was changed, but, the use of a co-substrate with a high concentration of fibers did not improve the methane production too much. Secondly, in order to consider the valorization of lignocellulosic components through the production of by-products, the effect of these components on the municipal solid wastes anaerobic digestion performance was evaluated. When the paper waste was removed, the biodegradability of the feedstock increased allowing the specific methane production to increase. Nevertheless, the digester was more fragile against instabilities and the digestate quality decreased if short retention times are applied. Next, low-temperature and ultrasounds pretreatments, strategies that have not been used too much for the degradation of lignocellulosic components, were studied to increase the methane production during the anaerobic co-digestion of barley waste and pig manure. Low-temperature and ultrasound pretreatment increased the methane production in a 27 and 12% respectively but only the first one had a positive energy balance. Finally, rumen, a waste from the slaughterhouse industry was used as inoculum and as co-substrate to bring hydrolytic bacteria able to improve the degradation of Napier grass. The results showed that, when rumen is used as inoculum it need to be mixed with an inoculum with high buffer capacity and a co-substrate with alkalinity need to be used to avoid long start-up periods. The methane production only increased at the beginning and in a long-term, the microbial community was governed by the substrate and not by the rumen. However, rumen did not increase the methane production when it was used as a co-substrate because the digester conditions were not optimal for the activity of hydrolytic bacteria. All the experiments were carried out in the laboratory and the conclusions are considered a progress for the energy production through the use of lignocellulosic substrates. / El incremento de la demanda energética y la consecuente generación de residuos ponen en peligro la sostenibilidad del futuro. Es por eso que la digestión anaeróbica resulta ser una solución factible para mitigar el problema ya que se puede generar electricidad, calor y fertilizante a partir de los residuos orgánicos. El incremento de la producción de metano se consiguió a partir de la co-digestión de residuos con características complementarias. Aun así, no siempre se consigue extraer todo el potencial metanogénico de los residuos, especialmente, en el caso de los sustratos ligno-celulósicos. Los compuestos ligno¬celulósicos son estructuras complejos entre la lignina, la hemicelulosa y la celulosa con enlaces resistentes a la degradación microbiana que se encuentran en los residuos agro-industriales, los residuos municipales y los cultivos energéticos. En la tesis, se ha buscado aumentar la viabilidad económica de las plantas de digestión anaeróbica que tratan residuos con componentes ligno-celulósicos. Se usaron distintas nuevas estrategias para aumentar la degradabilidad de la materia ligno-celulósica como los pretratamientos térmicos de baja temperatura y de ultrasonidos y la integración del rumen, un residuo de la industria cárnica, para aportar bacterias hidrolíticas. Para valorar la opción de separar estos componentes para la formación de sub-productos, se estudió su efecto sobre el rendimiento del digestor en términos de estabilidad, producción de metano y calidad del digerido para así poder implementar la producción se sub-productos. Los estudios realizados en esta tesis doctoral se llevaron a cabo a escala de laboratorio y las conclusiones han supuesto un avance para el aprovechamiento energético de los residuos ligno-celulósicos en el futuro.

La consulta íntegra de la tesi, inclosos els articles no comunicats públicament per drets d'autor, es pot realitzar prèvia petició a l'Arxiu UPC / This Thesis focuses on the study of the catalytic production of hydrogen from a biofuel, namely the bioethanol. It also studies the subsequent purification of pre-cleaned reformate streams. The end use of the hydrogen produced is to feed fuel cells to power portable and mobile applications. In this Thesis, two types of catalysts have been developed. One consisting of RhPd/CeO2 catalysts aimed at generating hydrogen via the ethanol steam reforming. On the other hand, Au/TiO2 catalysts have been investigated to eliminate carbon monoxide from reformate streams. The developed catalysts have been tested under practical operational conditions. The developed catalysts have been characterized ex situ, in situ and under reaction conditions. The operando studies allowed for the investigation of the reorganization of the metals driven by the reactive atmosphere. Finally, the miniaturization of the hydrogen production and purification scale has been investigated. To achieve this goal, the developed catalysts have been implemented on microreactors composed of channels measuring only few microns. / A la present Tesi doctoral s'estudien la producció catalítica d'hidrogen a partir d'un biocombustible, el bioetanol, i la seva posterior purificació per alimentar piles de combustible que proporcionin energia a aplicacions portàtils i mòbils. S'han desenvolupat dues famílies de catalitzadors, una de RhPd/CeO2 per generar hidrogen a partir de la reformació amb vapor d'etanol, i l'altra d'Au/TiO2 per eliminar el monòxid de carboni dels corrents de reformació pre-purificats. Els catalitzadors han estats estudiats en condicions de reacció properes a la indústria. En aquesta tesi s'han caracteritzat els catalitzadors ex situ, in situ i també en condicions “operando” o de reacció. L'estudi en “operando” dels catalitzadors ha permès investigar la reorganització induïda pels reactius dels components del catalitzador. Finalment, també s'ha estudiat la miniaturització tant del sistema de generació com de purificació de l'hidrogen per tal d'alimentar aplicacions de petit consum. Per això, s'han utilitzat microreactors composats de canals en l'escala del micròmetre.

The development of treatment processes to reduce or reuse sewage sludge is crucial for a proper environmental management. Segregating primary from secondary sludge allows for better reuse of secondary sludge, since digested secondary sludge is better suited for agricultural application, containing about double concentration in nutrients but significantly less contaminants. However, secondary sludge (also called waste activated sludge (WAS)) is difficult to dewater compared with primary sludge due to the existence of colloidal materials and extracellular polymeric substances (EPSs), which strongly retain water. WAS is also more difficult to digest under anaerobic conditions due to the presence of glycan strands in microbial cell walls. The low dewaterability and digestibility of WAS can be improved by applying treatments, which can partially disintegrate the WAS by disrupting flocs and cells and solubilising the EPSs. The treatments studied in this thesis were ultrasound, low-temperature thermal and alkali with NaOH. Specifically, it has been analysed the effect of the aforementioned treatment on WAS rheology, dewatering, hygienisation and anaerobic digestion. Rheology is the study of stress-strain relationships of viscoelastic materials. All the sludges analysed (untreated and treated) behaved as non-Newtonian pseudoplastic fluids, which indicates that the viscosity decreases with the applied shear rate. The sludges were also thixotropic (showing a hysteresis area in the plot of stress versus shear rate), which means that the viscosity is time dependent. The three aforementioned treatments resulted in the reduction of the steady state viscosity and the hysteresis area. Complementarily, a rheological structural model was proposed to examine the variations in the thixotropic behaviour of WAS after the application of the treatments. Sludge dewatering is essential to obtain a product dry enough to allow a reduction in storage volume. The three conditions of the thermal treatment (60, 80 and 90 ºC; 1 h, including the heating time to reach the temperature) and the higher intensities of ultrasound (27,000 kJ/kg TS) and alkali (157 g NaOH/kg TS) treatments improved sludge dewatering by centrifugation. To further evaluate the effect of treatments on the sludge dewatering, the EPSs contained in sludge were extracted and characterised. The EPSs were fractionated to generate two different EPS fractions: loosely bound EPSs (LB-EPSs) and tightly bound EPSs (TB-EPSs), where the latter is the innermost fraction and harder to release. An analysis of the untreated sludge revealed that the proteins, followed by the humic acids and polysaccharides, were the major constituents of the EPSs. Each of these components was primarily observed in the TB-EPS fraction. The treatments, particularly the alkali treatment, thoroughly solubilised the EPS, as indicated by the increase in the TOC, protein, humic acid and polysaccharide contents in the LB-EPS fraction. As a result, the dewaterability of WAS was improved. Hygienisation of the sludge is of uttermost importance if the sludge is intended for agriculture. The level of hygienisation was evaluated using three indicator organisms: Escherichia coli, somatic coliphages (SOMCPH) and spores of sulfite-reducing clostridia (SSRC). The thermal treatment at 80 ºC and the alkali treatment at 157 g NaOH kg TS allowed the hygienisation of the sludge, thus satisfying normal levels accepted by the EPA and the 3rd official draft from the EU. Conversely, the conditions tested for the ultrasound treatment barely reduced the levels of microbial indicators. Mesophilic anaerobic digestion is a widely used method to stabilise the sludge. The alkali pre-treatment (157 g NaOH/kg TS) exhibited the greatest methane production increase (34%) followed by the ultrasonication (27,000 kJ/kg TS; 13%), whereas the thermal pre-treatment (80 ºC, 15 min) presented a methane potential similar to the untreated sludge. However, the use of NaOH as a pre-treatment is rather limited because of the rising sodium concentration in the digester. / El desarrollo de procesos para la reducción o reutilización de los lodos resulta determinante para una apropiada gestión medioambiental. Tratando por separado el lodo activado del primario (y no la mezcla como suele hacerse) se favorece el uso del lodo activado en agricultura tras su digestión, ya que el lodo activado contiene el doble de nutrientes y menor carga contaminante que el primario. No obstante, el lodo activado (también denominado lodo secundario o biológico) es más difícil de deshidratar que el primario, ya que presenta una estructura interna organizada de flóculos unidos por las sustancias poliméricas extracelulares (EPSs, por sus siglas en inglés), las cuales atrapan el agua. En este contexto, la reología, que es la ciencia que estudia las relaciones entre la fuerza y la deformación de los materiales, es una herramienta muy útil para la caracterización de la viscosidad o estructura interna de los lodos. El lodo activado es también más difícil de digerir anaeróbicamente debido a las cadenas de glicanos presentes en las paredes celulares de las bacterias. En resumen, para poder deshidratar y digerir un lodo activado será necesario acondicionarlo previamente mediante tratamientos, con el fin de solubilizar las EPSs y aumentar su biodegradabilidad. Si además el lodo quiere destinarse a agricultura deberá estar higienizado. En esta tesis se ha estudiado el efecto de tres tratamientos (ultrasonido, térmico a baja temperatura y alcalino con NaOH) sobre la reología, deshidratación, higienización y digestión anaerobia de lodos activados. Los tres tratamientos redujeron considerablemente la viscosidad del lodo debido a la solubilización de la las EPSs. Así mismo, la solubilización de la EPSs facilitó la expulsión del agua confinada dentro de los flóculos del lodo, mejorando la deshidratación mediante centrifugación. El tratamiento alcalino con dosis de NaOH elevadas fue el que más EPSs solubilizó, de manera que fue el que permitió extraer más agua y el que más aumentó la producción de metano, además de higienizar el lodo. No obstante, este tratamiento tiene el inconveniente de incrementar la concentración de sodio en el digestor, lo cual podría llegar a inhibir el proceso de digestión. Los ultrasonidos redujeron notablemente la viscosidad, además de mejorar la deshidratación y la digestión del lodo. Sin embargo, este tratamiento no fue capaz de higienizar el lodo. El tratamiento térmico a baja temperatura aumentó muy ligeramente la producción de metano (posiblemente debido al corto tiempo de exposición) y permitió deshidratar e higienizar el lodo.

The aim of this thesis is studying and characterizing a ball burnishing process assisted with vibrations. By introducing vibrations in the overall process, results are enhanced if compared to the ones derived from a conventional ball burnishing operation. The main contribution of this research is exploring the effectiveness of a special vibrations-assisted ball-burnishing tool, with no current commercial homologous. The first step of the research was obtaining a model to predict the dynamic behavior of the tool's plates, taking into account the physical analysis of the vibration of rigid thin plates. The results were used to determine the most relevant features of the vibrations-assisted tool, and its nominal working frequency. From here, a functional prototype was manufactured, and was used to perform the experimental tests on specimens made of two materials: aluminum A92017 and steel G10380. To evaluate the benefits of the process, the following quality indicators were taken into account: average surface roughness, micro-hardness profile and compressive residual stresses induced in the tested specimens. Furthermore, the additional forces and energy added to the process due to the assistance of the vibrations were calculated. An experimental study of the footprint shape after burnishing was then carried out. Tests were performed in two conditions along the whole thesis: conventional burnishing and assisted by vibrations. The results achieved in both conditions were / El objetivo fundamental planteado en esta tesis es el estudio del proceso de bruñido con bola asistido por vibraciones. La introducción de las vibraciones se realiza para mejorar los resultados que se obtienen en un bruñido convencional, siendo ésta una aportación novedosa, ya que no existe en el mercado ninguna herramienta con características homólogas. Se ha partido de la obtención de un modelo para predecir el comportamiento dinámico de las placas que conforman la herramienta, a partir del análisis físico del fenómeno de la vibración de una placa delgada rígida, el cual ha posibilitado predeterminar las características más relevantes de la herramienta y la frecuencia a la que trabajará la misma. A partir de aquí se ha fabricado un prototipo funcional con el que se realizarán y se presentarán las pruebas experimentales en piezas de dos materiales: aluminio A92017 y acero G10380. Para evaluar las bondades del proceso se han tomado como indicadores de la calidad del mismo: la rugosidad superficial, la micro-dureza del perfil bruñido y las tensiones residuales compresivas introducidas en las piezas ensayadas. Además, se calculan las fuerzas adicionales aportadas al proceso de bruñido, así como la energía añadida a éste, producto de la asistencia de las vibraciones. En una última etapa se lleva a cabo un estudio experimental de la forma de la huella que deja la pasada de bruñido. Se efectúan ensayos de bruñido convencional y asistido con vibraciones y se analizan los resultados alcanzados en ambas condiciones. Al finalizar, se llegan a conclusiones importantes sobre el proceso de bruñido con bola asistido con vibraciones, y sobre las hipótesis y objetivos que establecieron los puntos de partida de esta tesis. Además, se realizan toda una serie de recomendaciones acerca de nuevos estudios que podrían abordarse en un futuro inmediato, cuyas bases fundamentales quedan establecidas en este trabajo.

En estructures pretesades sotmeses a ambients corrosius, s'està estudiant la possibilitat de substituir els tendons d’acer per tendons que no pateixin els efectes de la corrosió. En aquest sentit, els materials compostos Fibre Reinforced Polymer (FRP) són una opció duradora en el disseny d'estructures de formigó pretesat degut a les seves altes propietats mecàniques, pes lleuger i alta resistència a la corrosió. No obstant, un dels reptes associats amb aquesta opció es troba en el desenvolupament d'un sistema d'ancoratge adequat per als tendons de FRP . Per això aquesta investigació ha estudiat la resposta mecànica d’ancoratges d’unió adhesiva per a tendons de FRP sota càrregues quasi-estàtiques, de fatiga i en funció del temps. Aquest objectiu s'ha aconseguit mitjançant la combinació d'una campanya experimental i un treball de modelatge amb el mètode dels elements finits. En aquest sentit s’han dut a terme assaigs experimentals quasi-estàtics en els ancoratges d’unió adhesiva, observant que la ruptura del sistema es produïa en la unió adhesiva entre l’adhesiu i el tendó. En conseqüència, les principals variables estudiades van ser l’espessor de l'adhesiu i la longitud d’adhesió. A través d’una campanya de modelatge numèric amb diferents models, de complexitat creixent, del material adhesiu, es va investigar la resposta quasi-estàtica de l'ancoratge i el seu mecanisme de fallada. El model numèric va ser capaç de predir les dades enregistrades experimentalment quan el modelatge de l’adhesiu es va realitzar amb elements cohesius amb dany progressiu. A més, s’ha desenvolupat una formulació analítica (i validat amb èxit) amb l'objectiu de proporcionar una distribució aproximada de les tensions de tall que es produeixen en la capa adhesiva per ancoratges amb adhesius que es comporten principalment elàstic lineal fins a ruptura. D’altra banda l'ancoratge d’unió adhesiva també es va investigar sota els fenòmens dependents del temps. Per això es van dur a terme assaigs de fluència en unions simples Single Lap Joints ( SLJs ), per tal d'obtenir una llei experimental de fluència, i es van realitzar assaigs de relaxació de la tensió en els ancoratges per estudiar la pèrdua de càrrega en funció del temps. Durant aquests assaigs de relaxació es va estudiar la tècnica del retesat amb l’objectiu d’estudiar l’evolució de les pèrdues de tensió. Es va observar que la tècnica del retesat permet assolir càrregues de treball superiors amb una pèrdua de càrrega mínima. A més a través d’un model visco-plàstic es va predir el temps de fallada a fluència de les SLJs i els ancoratges, basat en la llei de Bailey-Norton i calibrat amb les dades experimentals obtingudes en els assaigs de fluència de les SLJs. El dany de fluència es va modelar mitjançant la degradació de la tensió de fluència plàstica de l'adhesiu i el model numèric es va utilitzar per predir la pèrdua de càrrega dels ancoratges sota el fenomen de relaxació de la tensió. Els resultats enregistrats experimentalment van ser predits adequadament amb el model numèric proposat. Finalment, es va investigar la resposta a la fatiga dels ancoratges d’unió adhesiva. Es van avaluar quatre configuracions d’ancoratge sota tres càrregues de fatiga d'amplitud constant. Els resultats experimentals van permetre l’obtenció d’una corba de vida a fatiga dels ancoratges en funció del nombre de cicles. Mitjançant el mètode d’elements finits, també es va investigar el comportament a fatiga. La llei cohesiva obtinguda en l'anàlisi quasi-estàtic es va utilitzar en el model de la fatiga, on el dany per fatiga s’ha basat en la degradació de les propietats dels elements cohesius. El model numèric va predir amb èxit l'evolució dany per fatiga i la vida per fatiga observada experimentalment . A partir del treball experimental i numèric realitzat en aquesta recerca, es proposen les recomanacions més pertinents per a un possible ús dels ancoratges d’unió adhesiva per tendons FRP en aplicacions de pretensat. / In prestressed structures subjected to corrosive environments, consideration is being given to replacing the steels tendons with non-corrosive tendons. In this respect, Fibre Reinforced Polymer (FRP) materials are a durable option in the design of prestressed concrete structures for use in corrosive environments due to their high mechanical properties, light weight and high resistance to corrosion. However, one of the challenges associated with this option lies in developing a suitable anchorage system for FRP tendons. In the present work, the mechanical response of circular adhesively bonded anchorages for FRP tendons has been investigated under quasi-static, time-dependent and fatigue loading. This has been achieved through a combination of an experimental campaign and finite element modelling work. Experimental quasi-static tests of adhesively bonded anchorages were undertaken with failure occurring in the adhesive-tendon interface. The main variables assessed were the adhesive thickness and the bonded length. In order to investigate the quasi-static response of the bonded anchorage and its failure mechanism, a campaign of numerical modelling was carried out with different material models of increasing complexity for the adhesive layer. A cohesive zone model with progressive damage in the bonded joint was found to be in reasonable agreement with the experimentally recorded data. Additionally, an analytical formulation was developed (and validated against experimental data) with the aim to provide an approximate shear stress distribution in the bonded joint for circular anchors with adhesives which mainly behave linearly elastic up to failure. The adhesively bonded anchor for FRP tendons was also investigated under the time-dependent phenomena. Creep tests on Single Lap Joints (SLJs) were conducted in order to obtain an experimental creep law whereas stress relaxation tests were conducted on adhesively bonded anchorages to study the load loss in time. Furthermore, the restressing technique was assessed during the stress relaxation tests by restressing the specimens, to the original tensioning load, when the load loss was stabilised and constant. It was found that the restressing technique allows for the working load of the composite tendon to be reached with a minimum load loss. A visco-plastic material model, based on the Bailey-Norton law, was calibrated with the experimental data obtained from the creep tests and utilised to predict the creep time to failure of SLJs and anchorages. The creep damage was modelled by degrading the plastic yield stress of the adhesive. The viscoelastic model was also used to predict the load loss of the anchors under the stress relaxation phenomenon. The predicted load loss results were found to be in good agreement with the experimental results recorded. Finally, the fatigue response of the bonded anchorages was investigated. Anchorages with four different adhesive thicknesses were evaluated under three constant amplitude fatigue loadings. The experimental fatigue response of adhesively bonded anchorages was discussed and an experimental load-life average curve was obtained for all the anchorages. The fatigue behaviour was also predicted using Finite Element Analysis. A multi-linear traction-separation cohesive zone model was implemented at the adhesive-tendon interface. The cohesive law obtained in the quasi-static analysis was utilised in the fatigue model. The fatigue damage model utilised in this research was based on the degradation of the cohesive elements taking into account the fatigue damage evolution. The damage model was able to successfully predict the fatigue damage evolution and failure life experimentally observed. From the experimental and numerical work conducted in this investigation, the most relevant recommendations are proposed for a potential use of adhesively bonded anchorages for CFRP tendons in prestressing applications.

Neste trabalho foi estudado um problema de dimensionamento de lotes em uma indústria química brasileira, cujo objetivo era determinar o tamanho dos lotes dos produtos para atender às demandas, minimizando os custos produtivos. Os itens podem ser produzidos em máquinas paralelas distintas, através de diferentes processos, e devem ser armazenados em taques cativos, exclusivos a um produto, ou multipropósitos, compartilhado entre produtos, desde que não simultaneamente. Foram propostos dois modelos matemáticos de programação inteira mista para representar o problema, o primeiro apresentava uma função objetivo compreendendo o preço das matérias-primas consumidas nas reações, os gastos com a estocagem de produtos e o custo de descarte de produtos quando os tanques de armazenamento não tiverem capacidade suficiente para armazená-los, já o segundo estendendo este modelo para considerar custos de preparação de máquina. Experimentos computacionais com os modelos propostos, utilizando instâncias geradas a partir dos dados fornecidos pela empresa, mostraram que o software de otimização empregado foi capaz de resolver poucas instâncias, após uma hora de processamento. Portanto, foram propostas heurísticas construtivas do tipo LP-and-fix e relax-and-fix, além de heurísticas de melhoria do tipo fix-and-optimize. Após serem realizados testes com essas heurísticas, constatou-se que algumas proporcionaram a obtenção de soluções factíveis de boa qualidade, quando comparadas às obtidas pelo software, sendo ainda capazes de resolver um maior número de instâncias / In this dissertation the lot sizing problem in a chemical Brazilian industry was studied, with the goal to determine the products lot size to satisfy the demands, minimizing the production costs. The items can be produced on distinct parallel machines through different processes and then must be stored in exclusive tanks, used by only one product, or multipurpose tanks, when more than one product can use the tank, but not simultaneously. Two models were proposed to represent the problem, the first one aiming to minimize the price of raw material consumed in the reactions, storage product spending and the cost of discarting products when the storage tanks do not have enough capacity to store them, and the second one considering setup cost either. Computational experiments using the proposed models, with instances were generated from the data provided by the company, showed that the used optimization software was able to solve only few instances after processing for one hour. In this dissertation we propose constructives heuristics such LP-and-fix and relax-and-fix, and improving heuristics like fix-and-optimize. After performing the tests with those heuristics, it was found that some of them provided feasible solutions with good quality, when compared to the ones obtained by the software, and they were also able to solve a larger number of instances

Este trabalho é norteado pela hipótese de que subsidiárias de empresas multinacionais do setor químico têm expandido seu papel no país ao longo das últimas décadas, indo além das atividades tradicionais como venda e produção, passando a realizar novas atividades como pesquisa e desenvolvimento (P&D) e marketing estratégico. As atividades de P&D por sua vez também têm evoluído desde projetos mais básicos focados em ajustes de formulações às condições locais para projetos mais complexos que geram novos conhecimentos e possuem alto potencial de aplicação em outras geografias. Por meio de um estudo de caso em uma unidade de negócios de uma subsidiária brasileira de uma multinacional da indústria química, este trabalho investiga, descreve e discute a natureza da inovação nesta unidade de análise. Neste trabalho, são estudados atributos do pool de ideias e do pipeline de projetos proveniente da unidade de negócios sob a luz de informações internas e do referencial teórico proveniente de uma revisão sistemática da literatura. Observou-se que há um grande foco e estímulo ao desenvolvimento da inovação na unidade de análise, e que a mesma parece estar em um processo evolutivo em que se começa a notar o surgimento de ideias e de projetos de inovação disruptivos. A partir do estudo de caso e da discussão baseada em dados internos e na literatura, é possível ilustrar o funcionamento das atividades de P&D em uma multinacional da indústria química com subsidiária baseada no Brasil. Como sugestões para trabalhados futuros é apontada a possibilidade de se organizar um estudo da inovação em subsidiárias no Brasil que envolvam diferentes empresas e setores da indústria. / This work is guided by the hypothesis that subsidiaries of multinational chemical companies have expanded their role in the country over the last decades, going beyond traditional activities such as sale and production, starting to carry out new activities such as research and development (R&D) and strategic marketing. R&D activities have also evolved from more basic projects focused on formulation adjustments to local conditions, to more complex projects that generate new knowledge and have a high potential for application in other geographies. Through a case study in a business unit of a Brazilian subsidiary of a chemical industry multinational, this work investigates, describes and discusses the nature of innovation in this unit of analysis. In this work, the attributes of the idea pool and the project pipeline from the business unit are studied in the light of internal information and the theoretical framework from a systematic review of the literature. It was observed that there is a great focus and stimulus to the development of innovation in the unit of analysis, and that it seems to be in an evolutionary process in which one begins to notice the emergence of ideas and disruptive innovation projects. From the case study and the discussion based on internal data and literature, it is possible to illustrate the operation of R & D activities in a multinational chemical industry with a subsidiary based in Brazil. As suggestions for future work is pointed out the possibility of organizing a study of innovation in subsidiaries in Brazil that involves different companies and types of industries.

A presente pesquisa tem como principal tema a decisão estratégica de fazer ou comprar no contexto do setor químico. Apesar de ser um tema relativamente recorrente, o foco da literatura neste tipo de pesquisa tem sido no contexto da indústria automotiva e/ou eletroeletrônica. Indaga-se, então, se existe aderência entre os modelos teóricos e o que ocorre nas empresas do contexto químico brasileiro. O desenvolvimento teórico desta pesquisa teve por base uma compilação dos principais modelos de fazer ou comprar apresentados pela literatura desde final da década de 1980. O desenvolvimento empírico teve por base uma pesquisa qualitativa, predominantemente exploratória, baseada na técnica de estudo de casos múltiplos, contando com uma amostra de duas empresas de grande porte no contexto químico brasileiro. Foi verificado que existe um razoável nível de aderência entre o que preconiza a literatura e o que é feito nas empresas pesquisadas, mas existem algumas contribuições relevantes que podem ser consideradas para os modelos de fazer ou comprar existentes na literatura. / The main theme of this research is the strategic decision making process associated with make-or-buy decisions. Said theme has been developed in the literature with primary focus on automotive and hardware industries, not chemical industry, what leads to the main question of this research: what is the adherence level between the literature and the actual behavior of the chemical industry, when going through this type of strategic decision making process? The literature research development was primarily based on a compilation of different makeor- buy decision models which have been presented by the literature since late eighties. The empirical research development was based on an exploratory qualitative approach, with the aide of multiple case studies techniques on a small sample of two large Brazilian chemical enterprises. The main result indicates a reasonable level of adherence to what the literature has presented so far, however there are other important aspects that should be taken as relevant contributions from the empirical research to the existing make-or-buy decision process models.

A adoção crescente das normas internacionais de contabilidade, as IFRS, é o reflexo de que a comunicação entre empresas, credores, investidores e demais \"stakeholders\" acompanha as mudanças radicais observadas nos negócios. O trabalho de elaboração de tais normas internacionais ficou a cargo do \"Board\" do IASB e já se identifica ampla convergência no plano mundial rumo às citadas IFRS. A IFRS 1, denominada \"First Time Adoption\" refere-se aos requisitos a serem observados no primeiro exercício em que uma empresa publica suas demonstrações em norma contábil local e em IFRS. Este estudo tem por objetivo verificar se, no ano da primeira adoção, há diferença nos grupos de contas patrimoniais do ativo e do passivo nos balanços das empresas dos setores químico e de mineração listadas nas bolsas do Reino Unido, da França e da Alemanha, calculados com base no último balanço em norma contábil local, em relação aos mesmos grupos da primeira demonstração publicada em IFRS. Através da pesquisa nas bolsas de valores destes três países, foram analisadas 42 empresas, sendo 18 empresas de mineração e 24 companhias do segmento químico. Foram utilizados os testes estatísticos t-student para amostras emparelhadas e Wilcoxon para a comparação das médias das diferenças das proporções de cada grupo do patrimônio em relação ao ativo ou passivo total. Os resultados demonstram que existe diferença significativa na estrutura dos grupos do ativo e do passivo pré e pós-adoção das IFRS, tanto na comparação entre países quanto na comparação entre setores. Os resultados mostram também que cada grupo sofreu impactos de magnitudes diferentes. Para os setores e países desta amostra, a comparação dos resultados desfaz a conclusão equivocada de que a adoção das normas contábeis internacionais traz consigo o benefício da uniformidade do padrão contábil e que os efeitos das alterações nos grupos patrimoniais em decorrência da transição de um padrão contábil local para as IFRS devem ser levados em consideração quando da escolha do balanço para uma análise no ano da primeira adoção. / The increasing adoption of International Financial Reporting Standards, IFRS, is consequence of the communication among enterprises, creditors, investors and stakeholders that is following the deep changes that have been taken place in the businesses. The international standards were set by IASB and it has already been identified a worldwide convergence toward IFRS. IFRS 1, named as First Time Adoption, applies to the requisites that have to be considered in the first-year balance sheet in IFRS reconciled with the local GAAP. This study has for objective to verify if there are differences in the current and noncurrent assets as well as in the current and non-current liabilities groups stated within the balance sheets of mining and chemicals companies listed at London Stock Exchange, Frankfurt Stock Exchange and Paris-Euronext, considering the local GAAP for each country and the first time adoption of IFRS. After a research in the referred stock exchanges, 42 companies (18 mining and 24 chemicals) have been picked and taken into analysis. The statistics are based on Wilcoxon and t-student for paired samples tests. They have compared the average of the differences in the current and non-current groups in relation to total assets or liabilities. The results show there are significant differences in the groups of assets and liabilities taken before and after the first adoption of international financial reporting standards, considering both comparisons between countries and sectors. The results also demonstrate that the groups of current and non-current accounts were impacted in different percentiles with the adoption of IFRS 1. The comparison of results illustrates that, when the analysis of a balance sheet in the first year adoption is necessary, the IFRS have not benefited the uniformity on accounting standards for the sectors and countries that have been used in this study and the effects of changes within assets and liabilities groups have to be taken into account as consequence of the transition from UK-GAAP, GER-GAAP and FRAGAAP to IFRS.