A reestruturação do Setor Elétrico Brasileiro introduziu uma nova categoria de clientes no mercado consumidor. Os chamados Clientes Livres, ao contrário dos Clientes Cativos, podem formalizar a aquisição de energia elétrica para atendimento dos requisitos de seu processo produtivo, através de contratos bilaterais, onde os prazos, os preços e os volumes são livremente negociados entre os agentes. A segmentação imposta pelas reformas do setor promoveu a competição na atividade de comercialização, repercutindo em novas responsabilidades para os agentes setoriais, com oportunidades para a busca de resultados financeiros, mas, por outro lado, com riscos associados que requerem adequado gerenciamento. Conseqüentemente, o estabelecimento de contratos neste ambiente evidencia a importância da adoção de estratégias de hedge adequadas para mitigar os riscos de exposição financeira dos Clientes Livres ao Mercado de Curto Prazo. Sob essa perspectiva, o texto aborda a formação de preços contratuais no curto e longo prazos, propõe critérios de risco para aferir as estratégias mais promissoras, de acordo com o perfil do consumidor, de modo a otimizar a obtenção de energia no Ambiente de Contratação Livre, contemplando, também, o efeito da recente possibilidade da comercialização dos excedentes de energia elétrica, como forma de flexibilização contratual para esta categoria de consumidores. / The power sector reforms in Brazil introduced a new sort of consumers in the electricity market. The Free Consumers are able to choose their suppliers and freely negotiate contractual terms. The restructuring process of electricity industry promoted the competition into the retail sales subindustry. It gave new responsibilities to market participants and also potential opportunities to reduce its energy costs. On the other hands, the Free Customers are requested to manage their own risks. It is important therefore the establishment of contracting strategies to hedge against price risks. As consequence, the purpose of this study is to address a methodology to implement short and long-term contract pricing and evaluate the risks associated with its strategies. Moreover, the work identifies the contracting decisions to optimize electricity costs accordingly to customer´s needs. Finally, it is presented a study on contract flexibility where an opportunity could be given to such kind of consumers, making possible to resell part of their electricity contracts.

A reestruturação do Setor Elétrico Brasileiro introduziu uma nova categoria de clientes no mercado consumidor. Os chamados Clientes Livres, ao contrário dos Clientes Cativos, podem formalizar a aquisição de energia elétrica para atendimento dos requisitos de seu processo produtivo, através de contratos bilaterais, onde os prazos, os preços e os volumes são livremente negociados entre os agentes. A segmentação imposta pelas reformas do setor promoveu a competição na atividade de comercialização, repercutindo em novas responsabilidades para os agentes setoriais, com oportunidades para a busca de resultados financeiros, mas, por outro lado, com riscos associados que requerem adequado gerenciamento. Conseqüentemente, o estabelecimento de contratos neste ambiente evidencia a importância da adoção de estratégias de hedge adequadas para mitigar os riscos de exposição financeira dos Clientes Livres ao Mercado de Curto Prazo. Sob essa perspectiva, o texto aborda a formação de preços contratuais no curto e longo prazos, propõe critérios de risco para aferir as estratégias mais promissoras, de acordo com o perfil do consumidor, de modo a otimizar a obtenção de energia no Ambiente de Contratação Livre, contemplando, também, o efeito da recente possibilidade da comercialização dos excedentes de energia elétrica, como forma de flexibilização contratual para esta categoria de consumidores. / The power sector reforms in Brazil introduced a new sort of consumers in the electricity market. The Free Consumers are able to choose their suppliers and freely negotiate contractual terms. The restructuring process of electricity industry promoted the competition into the retail sales subindustry. It gave new responsibilities to market participants and also potential opportunities to reduce its energy costs. On the other hands, the Free Customers are requested to manage their own risks. It is important therefore the establishment of contracting strategies to hedge against price risks. As consequence, the purpose of this study is to address a methodology to implement short and long-term contract pricing and evaluate the risks associated with its strategies. Moreover, the work identifies the contracting decisions to optimize electricity costs accordingly to customer´s needs. Finally, it is presented a study on contract flexibility where an opportunity could be given to such kind of consumers, making possible to resell part of their electricity contracts.

In Peru, the right to choose freely among products and services has not been developed in extent, right contained in the Code of Protection and Defense of the Consumer. In that order of ideas, this right is not alleged in courts to be enforced due its content is not well known. Therefore, our research has the purpose of analyzing common situations, where the right to choose freely among products and services is discussed with the objective to limiting its scope clear and evenly, which would greatly contribute to its compliance. / En el Perú, no se han desarrollado en extenso los alcances del derecho a elegir, libremente, entre productos y servicios, consagrado, actualmente, en el artículo 1º, inciso 1, literal f ) del Código de Protección y Defensa del Consumidor. En ese sentido, podemos manifestar que este derecho no se hace respetar a plenitud por parte de los consumidores, en la medida que su real contenido no es conocido. Por ende, en este breve artículo queremos pasar revista a aquellas situaciones de la vida cotidiana, en las cuales el respeto al derecho a elegir está en discusión, con el fin de que aplicando, básicamente, el método deductivo se clarifiquen los alcances del mismo, y situaciones que hoy no son pasibles de cumplimiento por parte de los proveedores, lo sean.

Ce travail présente une étude de la dynamique interfaciale de gouttes oscillantes dans une plage étendue de fréquences, en particulier dans le domaine des hautes fréquences. Nous avons développé une méthode de caractérisation de la dynamique des oscillations de gouttes, en présence d’un forçage externe imposé, sous la forme de variations de volume périodiques de faible amplitude sur une goutte attachée à l’extrémité d’un capillaire. Cette méthode permet d’identifier les modes d’oscillation des gouttes et d’en mesurer les fréquences et les taux d’amortissement. Cette méthode a été appliquée à différents systèmes liquide-liquide, en l’absence ou en présence de surfactants. Dans ce dernier cas, elle permet d’évaluer l’effet du comportement viscoélastique des interfaces sur la dynamique des oscillations. Ainsi 3 types d’interfaces ont été identifiés. Pour les interfaces de premier type (heptane/eau sans ajout de surfactant), chaque mode propre est modélisé par un oscillateur linéaire peu amorti. Les fréquences propres et les taux d’amortissement sont bien prédits par la théorie linéaire. Les interfaces de types 2 et 3 sont obtenues en ajoutant du pétrole brut à la phase dispersée. Les surfactants naturellement présents dans le pétrole (asphaltènes, résines) s’adsorbent à l’interface et lui confèrent des propriétés viscoélastiques. Pour les interfaces jeunes (type 2, moins de 20 minutes de vieillissement), les fréquences propres mesurées restent bien prédites par la théorie, qui considère des interfaces non contaminées, tandis que les taux d’amortissement sont de loin supérieurs aux valeurs théoriques. D’autre part, les interfaces vieillies (type 3) présentent des modes propres différents avec des fréquences de résonance supérieures à celles des interfaces jeunes. Dans ce cas, la dynamique de l’interface à haute fréquence est régie par l’élasticité du réseau formé par les espèces amphiphiles du pétrole brut. Les oscillations libres d’une goutte en ascension dans une phase externe stagnante, pour un système liquide-liquide sans ajout de surfactants, ont été étudiées. Les valeurs mesurées de la fréquence d’oscillation des 4 premiers modes sont en adéquation avec la théorie linéaire. Cependant les valeurs mesurées du taux d’amortissement sont très élevées par rapport aux valeurs théoriques, pour une interface non contaminée. En effet, des espèces résiduelles adsorbées à l’interface provoquent l’apparition d’un gradient de tension interfaciale par effet Marangoni et par suite une production de vorticité plus intense dans les couches-limites, ce qui conduit à l’augmentation de l’amortissement des oscillations. / We present an experimental study of oscillating drop interfacial dynamics at a wide frequency range, especially at high frequency. A characterization method of drops oscillation dynamics has been developed. The oscillations are generated by imposing low amplitude periodic variation of volume to a drop which is attached to a capillary tip. The present method is based on the identification of the drop eigenmodes and the determination of their frequencies and damping rates. It has been applied to characterize several liquid-liquid systems. Three types of interface have been identified. For interfaces of type 1 (heptane/water without added surfactant), each eigenmode is modelled by a weakly damped linear oscillator. Eigenfrequencies and damping rates are well predicted by the linear theory. Interfaces of Types 2 and 3 are obtained by adding crude oil to the disperse phase. Oil native surfactants (asphaltenes, resins) adsorb on the drop interface and provide the latter with viscoelastic behaviour. For young interfaces (type 2 with aging time below 20 minutes), eigenfrequencies remain well predicted by the theory, which deals with non contaminated interfaces, whereas the measured damping rates are significantly higher than the theoretical values. On the other hand, aged interfaces (type 3) exhibit different eigenmodes, of which eigenfrequencies are much higher than the resonance frequencies measured for the young interfaces. At high frequency, the dynamics of aged interfaces are governed by the elasticity of the network constituted by the crude oil amphiphilic species, while the dynamics of young interfaces are governed by interfacial tension. Freely decaying oscillations of a rising drop in a liquid at rest without added surfactant were also considered. Measured frequencies for the first four eigenmodes are in good agreement with the linear theory. However, measured damping rates are much higher than the theoretical rates for non contaminated interfaces. In fact, residual adsorbed species at the heptane/water interface induce Marangoni effects and thus gradients of interfacial tension. Therefore, vorticity production within the boundary layers is enhanced, which explains the observed increase of the oscillation damping rates.

This diploma work focuses on freely available and professional electronic information resources for environmental issues. These resources are only accessible from computer networks (such as the Internet or other digital data distribution networks). The thesis is divided into three parts. The first part defines typical users of such resources in connection with their user needs. In the other two parts freely available and professional electronic information resources for environmental issues are classified and reviewed while several resources are completed with both qualitative and quantitative analyses. This work also contains analyses of resources availability and it is provided with charts and graphs for better understanding of the topic.

En même temps que le traité de Lisbonne conférait valeur juridique contraignante à la charte des droits fondamentaux de l’Union européenne, il créait, par l’article 67, paragraphe 1, du traité sur le fonctionnement de l’Union européenne, une obligation pour l’Union et les États membres de respecter les droits fondamentaux dans la construction de l’espace de liberté de sécurité et de justice. Parce qu’il vise chacune des normes composant cet espace, ce commandement interroge particulièrement dans l’espace judiciaire européen en matière civile et commerciale où les règles de coordination des ordres juridiques nationaux sont partiellement réfractaires à l’influence des droits fondamentaux. La polysémie de la notion de respect permet d’envisager divers modes d’articulations de la charte et du droit de l’espace judiciaire européen en matière civile et commerciale. Si le principe hiérarchique paraît la modalité la plus évidente pour assurer le respect de la charte, il s’avère inapte à y parvenir, tant par lui-même que par le contexte spécifique d’application de la charte qu’impose l’espace judiciaire européen. Aussi conviendrait-il d’y substituer un mode d’articulation plus souple, la combinaison, afin de conformer la construction de l’espace sous étude à l’article 67, paragraphe 1, du traité sur le fonctionnement de l’Union européenne. / When the treaty of Lisbon gave Charter of Fundamental Rights of the European Union its legally binding force, it gave rise, in article 67, paragraph 1, of the Treaty on the Functionning of the European Union, to a legal obligation to respect fundamental rights while building the Freedom, Security and Justice Area. As this legal obligation concerns all the rules of this space, it raises questions in the European Judicial Area in civil and commercial matter where rules coordinating national legal systems are partially resistant to the influence of fundamental rights. Polysemy of the notion of respect make it possible to consider different ways for the Charter and the European Judicial Area law to interact. If the hierarchical principle seems to be the most obvious way to ensure the respect of the Charter, it transpires to be inappropriate by itself and because of the specific context fort the application of the Charter commanded by the European Judicial Area. So, it would be more convenient to substitue the hierarchical principle with a more supple way of interaction, the combination, so as to conform the studied space to the article 67, paragraph 1, of the Treaty on the Functionning of the European Union.

Persistent organic pollutants (POPs) are hydrophobic substances that readily sorb to organic matter in particles and colloids instead of being freely dissolved in the water phase. This sorption affects the bio­availability and environmental transport of the POPs. The major part of this thesis concerns the role of sediments as secondary sources of POPs. As the primary emissions decrease, contaminated sediments where POPs have accumulated can become the main source of contamination. If the contaminated sediment by time becomes covered with cleaner layers, the POPs are buried and no longer in contact with the aquatic environment. Experiments in this thesis showed, however, that new invading species can alter the sediment-water dynamics as a result of their bioturbation, i.e. mixing of sediment particles and pore-water. Marenzelleria spp., invading species in the Baltic Sea that burrow deeper than native species, were found to increase the remobilization of buried contaminants. The sediment-to-water flux was inversely related to the burial depth (2-10 cm) of the POP congeners (polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers) and also inversely related to the hydrophobicity of the congener. The flux was therefore most pronounced for less hydrophobic contaminants, which was linked to the bioirrigating behaviour of these species. Marenzelleria spp. also accumulated the buried POPs and increased concentrations in surface sedi­ment. Contaminants previously considered buried at a ’safe’ depth can thus be remobilized as a result of the invasion of Marenzelleria spp. in the Baltic Sea. One method to decrease the remobilization of contaminants from sediments is ’capping’, i.e. a layer of clean material is placed as a cap on the sediment. By amending the cap with active materials, which sequester the POPs and decrease their availability, thinner layers can be used (’active capping’ or ’thin-layer capping’). Results from an experiment with thin-layer capping using different active materials (activated carbon (AC) and kraft lignin) showed that both the sediment-to-water flux and the bioaccumulation by benthic species of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), hexachlorobenzene (HCB) and octachlorostyrene (OCS) decreased with increased thick­ness of the cap layer (0.5-5 cm). Amendments with active materials further increased the cap efficiency. AC was more efficient than kraft lignin, and a 3 cm cap with 3.3% AC reduced the flux and bioaccumulation with ~90%. The reduction of the sediment-to-water flux was inversely related to the hydrophobicity of the POP, and reductions in the flux had similar magnitudes as reductions in the concentration in deep-burrowing polychaetes, demonstrating the importance of bioturbation for sediment-to-water transport. In a one-year study on the levels of PCDD/Fs, PCBs, and HCB in a coastal area of the Baltic Sea, the correlations between the POP levels and the levels of particles and organic carbon in the water were found to differ for POPs of different structure and hydrophobicity. The levels of PCDD/Fs decreased to one third in May, which could be related to the increased sedimentation, i.e. water-to-sediment transport, during spring bloom.