The sinking of dense shelf waters down the continental slope (or “cascading”) contributes to oceanic water mass formation and carbon cycling. Cascading is therefore of significant importance for the global overturning circulation and thus climate. The occurrence of cascades is highly intermittent in space and time and observations of the process itself (rather than its outcomes) are scarce. Global climate models do not typically resolve cascading owing to numerical challenges concerning turbulence, mixing and faithful representation of bottom boundary layer dynamics. This work was motivated by the need to improve the representation of cascading in numerical ocean circulation models. Typical 3-D hydrostatic ocean circulation models are employed in a series of numerical experiments to investigate the process of dense water cascading in both idealised and realistic model setups. Cascading on steep bottom topography is modelled using POLCOMS, a 3-D ocean circulation model using a terrain-following s-coordinate system. The model setup is based on a laboratory experiment of a continuous dense water flow from a central source on a conical slope in a rotating tank. The descent of the dense flow as characterised by the length of the plume as a function of time is studied for a range of parameters, such as density difference, speed of rotation, flow rate and (in the model) diffusivity and viscosity. Very good agreement between the model and the laboratory results is shown in dimensional and non-dimensional variables. It is confirmed that a hydrostatic model is capable of reproducing the essential physics of cascading on a very steep slope if the model correctly resolves velocity veering in the bottom boundary layer. Experiments changing the height of the bottom Ekman layer (by changing viscosity) and modifying the plume from a 2-layer system to a stratified regime (by enhancing diapycnal diffusion) confirm previous theories, demonstrate their limitations and offer new insights into the dynamics of cascading outside of the controlled laboratory conditions. In further numerical experiments, the idealised geometry of the conical slope is retained but up-scaled to oceanic dimensions. The NEMO-SHELF model is used to study the fate of a dense water plume of similar properties to the overflow of brine-enriched shelf waters from the Storfjorden in Svalbard. The overflow plume, resulting from sea ice formation in the Storfjorden polynya, cascades into the ambient stratification resembling the predominant water masses of Fram Strait. At intermediate depths between 200-500m the plume encounters a layer of warm, saline AtlanticWater. In some years the plume ‘pierces’ the Atlantic Layer and sinks into the deep Fram Strait while in other years it remains ‘arrested’ at Atlantic Layer depths. It has been unclear what parameters control whether the plume pierces the Atlantic Layer or not. In a series of experiments we vary the salinity ‘S’ and the flow rate ‘Q’ of the simulated Storfjorden overflow to investigate both strong and weak cascading conditions. Results show that the cascading regime (piercing, arrested or ‘shaving’ - an intermediate case) can be predicted from the initial values of S and Q. In those model experiments where the initial density of the overflow water is considerably greater than of the deepest ambient water mass we find that a cascade with high initial S does not necessarily reach the bottom if Q is low. Conversely, cascades with an initial density just slightly higher than the deepest ambient layer may flow to the bottom if the flow rate Q is high. A functional relationship between S/Q and the final depth level of plume waters is explained by the flux of potential energy (arising from the introduction of dense water at shallow depth) which, in our idealised setting, represents the only energy source for downslope descent and mixing. Lastly, the influence of tides on the propagation of a dense water plume is investigated using a regional NEMO-SHELF model with realistic bathymetry, atmospheric forcing, open boundary conditions and tides. The model has 3 km horizontal resolution and 50 vertical levels in the sh-coordinate system which is specially designed to resolve bottom boundary layer processes. Tidal effects are isolated by comparing results from model runs with and without tides. A hotspot of tidally-induced horizontal diffusion leading to the lateral dispersion of the plume is identified at the southernmost headland of Spitsbergen which is in close proximity to the plume path. As a result the lighter fractions in the diluted upper layer of the plume are drawn into the shallow coastal current that carries Storfjorden water onto the Western Svalbard Shelf, while the dense bottom layer continues to sink down the slope. This bifurcation of the plume into a diluted shelf branch and a dense downslope branch is enhanced by tidally-induced shear dispersion at the headland. Tidal effects at the headland are shown to cause a net reduction in the downslope flux of Storfjorden water into deep Fram Strait. This finding contrasts previous results from observations of a dense plume on a different shelf without abrupt topography. The dispersive mechanism which is induced by the tides is identified as a mechanism by which tides may cause a relative reduction in downslope transport, thus adding to existing understanding of tidal effects on dense water overflows.

Les crises se développent en temps et en espace via les liens de dépendances entre les réseaux techniques vitaux au fonctionnement de la société : on parle alors d’effets cascade. Après avoir étudié les risques d’effets cascade liés aux actions des sapeurs-pompiers, ce travail compare deux modélisations techniques de ces effets cascades : les bases de données orientée graphe - contenant des zones d’influence statiques de chaque infrastructure réseau, et le couplage faible de deux simulateurs pour obtenir des zones d’influence évolutive – approche dont ce rapport propose une méthodologie d’application. Cette thèse s’intéresse également à l’amélioration de l’évaluation des conséquences d’un scénario de crise, en proposant une modélisation de l’évolution quotidienne des densités humaines sur un territoire. Un effet cascade entre réseaux techniques est facilité par la vulnérabilité de chaque infrastructure et ralenti par la résilience de chaque système. Cette thèse soumet donc une méthode d’évaluation de la vulnérabilité et la résilience des réseaux techniques, transposable aux différents réseaux et scénarios. Elle l’applique à des scénarios détaillés proposés par les opérateurs de trois réseaux d’eau potable, et discute de son extension à d’autres réseaux techniques. Ces résultats visent à proposer à la sécurité civile une vision globale des vulnérabilités et des stratégies de résilience mises en place par les opérateurs, et permet aux opérateurs de construire des outils de suivi de leurs capacités de résilience en cas de scénarios de crise. / Crisis spread spatially and temporally inside the society through dependency links between physical critical networks: these phenomena are called cascading effects. After exploring cascading effects linked to the intervention of the fire brigade, this PhD thesis compares two modelling techniques: graph oriented database incorporating static impacts zones, and coupling of simulators in order to define evolutionary impacts zones – a method for applying this latest approach is proposed. It suggests also improving the automatic assessment of consequences per crisis scenario, in modelling the variation of population density on a territory. The vulnerability of each infrastructure contributes to cascading effects but the system resilience helps to stop them. This work proposes a global method for assessing vulnerability and resilience of physical critical networks (PCN). It has been applied first on detailed scenarios proposed by three different water utility companies. This work discusses then the extension of this approach to others PCNs. These results aim at helping the civil safety institutions to have a global view of PCNs vulnerability and resilience strategies proposed by utility companies. They aim also to help utility companies to have indicators for assessing and following their weak and strength facing threats, and to better identify axes of improvement.

Background – Circular economy (CE) is gaining more and more importance in research, based on the great desire to change the linear fashion economy to a circular. A Product Service System (PSS) can contribute to the achievement of CE, as PSSs, such as take-back or repair services, bring back the garments to the fashion retail company into the CE. Regarding, closed-loop goals have been created from which the third goal needs to be recently achieved by the fashion industry. Closed-Loop Goal 3 deals with the cascading flow of garments, which sends a garment into multiple usage loops. To accomplish the cascading garment flow, this method connects several PSSs to close the loop, and fewer garments end in landfill. To achieve that, the involvement of customers and business partners is essential as they are purchasing and repatriating garments and materials into the cascading loops. Purpose – The research purpose is to offer new knowledge regarding how fashion retailers can implement cascading loop systems in the textile Closed-Loop Supply Chain (CLSC) and narrow the research gap of cascading loop creations. The study aims to investigate how to involve customers and business partners in PSSs through the digitalisation of cascading garment flow. By doing so, the cascading garment flow intends to achieve improved sustainable performance by allowing used garments to enter a cascading garment flow system.  Methodology – This thesis is a single case study that has been conducted through an abductive approach. The research is built on different customer and business partner involvement theories and the triple bottom line theory. Semi-structured interviews have been conducted as primary data collection. Additionally, the data has been supplemented by secondary data in the form of company documents such as sustainability reports. Afterwards, the data has been analysed qualitatively by thematic analysis and by the SDG assessment tool.  Findings – The results have shown that a mixture of smart service tools, stakeholder and customer communication can achieve customers and business partners' involvement in creating a cascading garment flow. Additionally, the findings offer an insight into the potential contribution of the SDG goal achievement, which is showing that the digitalised PSSs involving customers and business partners in the cascading flow can potentially obtain sustainable performance.  Practical implications & Research limitations – The cascading garment flow as the Closed Loop Goal 3 in CE is still a relatively unexplored area. However, the implementation is essential for sustainable performance and development. Therefore, it is suggested that other issues within the cascading garment flow should be investigated. Additionally, this research was mainly districted by the smaller selection of literature of former research, which did not offer much support.

This thesis concerns itself with the problems of manipulation with Cascading Style Sheets. The first aim is to create a library for manipulation with Cascading Style Sheets - an object interface of Cascading Style Sheet is proposed, a parser is generated by means of an appliance of JavaCC, the implementation of interface is completed and as a whole connected to a functional unit. The library enables reading Cascading Style Sheet and its transfer into an object representation, editing and subsequently exporting back to the text file. The second part of the thesis deals with the implementation of library for assign property values - every (X)HTML document is formed by the tree of elements to which the rules are consequently searched for in CSS and their declarations are asigned in the correct order. In conclusion of the thesis the DEMO application, which illustrates the possibilities of both libraries and facilitates performing of experiments or testing, is described. Hereafter the technique of profiling, which enables to find out the efficiently demanding passages, which can be optimised further, in the source code, is shown.

No description available.

As represas construídas em cascata no rio Tietê (Barra Bonita, Bariri, Ibitinga, Promissão, Nova Avanhandava e Três Irmãos) constituem em sistemas artificiais com grande importância ecológica, econômica e social. Com base nos dados físico-químicos e biológicos das seis represas, foram avaliadas as condições limnológicas, abundância da comunidade fitoplanctônica e zooplanctônica e o estado de trofia dos reservatórios através da aplicação do índice do estado trófico, desenvolvido por Carlson (1977). A utilização da concentração de fósforo para determinação do índice é o que deu melhor resultado, mostrando uma redução gradual de sua concentração nas represas seqüenciais, principalmente no período do verão. Os reservatórios que se mostraram eutróficos como o de Barra Bonita, Bariri e Ibitinga apresentaram uma maior abundância e freqüência de florescimento das algas pertencentes a classe Cyanophyceae principalmente das espécies Microcystis aeruginosa. Algumas espécies de Rotifera, como Asplanchna sieboldi, Brachionus caliciflorus e Kellicottia bostoniensis, e de Copepoda Calanoida Notodiaptomus iheringi, também serviram de indicativos do estado trófico dos sistemas, já que esses estão associados a ambientes eutróficos. / Reservoirs built in cascade in Tietê river (Barra Bonita, Bariri, Ibitinga, Promissão, Nova Avanhandava and, Três Irmãos) constitute artificial systems with a high ecological, economic and social relevance. Based on the physical, chemical and biological data from the six reservoirs, limnological conditions were evaluated, the abundance of phytoplankton and zooplankton communities and the trophic state of reservoirs through the application of trophic state index, developed by Carlson (1977). The use of phosphorus concentration to determine the index gave the best result, showing a gradual reduction of its concentration in the sequential reservoirs, especially in summer period. The reservoirs that showed up to be eutrophic like Barra Bonita, Bariri and Ibitinga presented a higher abundance and frequency in development of algae belonging to the Cyanophyceae class, especially of Microcystis aeruginosa species. Some species of Rotifera such as Asplanchna sieboldi, Brachionus calyciflorus and, Kellicottia bostoniences, and of Copepoda Calanoida Notodiaptomus iheringi, also served as indicative of trophic state for these systems, since they are associated to eutrophic environments.

Ces travaux de thèse s’intéressent à une stratégie de fin de vie naissante : le repurposing. Nous le définissons comme un processus industriel par lequel des produits en fin d’usage sont réutilisés dans des applications distinctes. À la fin de leur premier usage, les produits sont réintégrés dans la chaine industrielle en vue d’une nouvelle utilisation dans une autre application. On parle également d’utilisations en cascade. Le but avoué est la conservation de la valeur-ajoutée des produits, aussi longtemps que possible. Cette stratégie s’inscrit aux côtés d’autres stratégies de réutilisation plus connues telles que le réemploi et le remanufacturing.L’illustration principale de la littérature, qui constitue également notre terrain d’étude, concerne les batteries au lithium. Utilisées initialement dans les véhicules électriques, elles sont aujourd’hui recyclées lorsque leurs capacités de stockage diminuent de 20 à 30%. Prolonger leur durée de vie par une seconde application, e.g. un usage stationnaire, permettrait de différer les étapes de recyclage tout en maximisant le maintien de la valeur ajoutée lors de la fabrication. Malgré ces avantages, les exemples de transformations de produits pour des applications en cascade restent à l’état de démonstrateurs, en particulier parce qu’aujourd’hui ces produits et leur chaine de valeur ne sont pas conçus avec des stratégies supportant leur réutilisation.L’objectif de ces travaux est d’apporter aux équipes de conception une vision claire de ce qu’est la stratégie de réutilisation en cascade, de comment l’intégrer lors des étapes amont du processus de conception et de guider l’évaluation environnementale correspondante, afin de les accompagner pour une réelle industrialisation des produits repurposés. En ce sens, nous émettons trois propositions.La première consiste en une classification des caractéristiques propres aux solutions en cascade selon trois axes : le produit, le processus de (re)fabrication et le modèle d’affaire envisagé. À travers ce cadre, nous décrivons les dimensions et les caractéristiques des offres de produits repurposés. Elles sont alors utilisables pour l’établissement de compromis dès les phases amont de conception. Celles-ci sont issues d’une étude bibliographique couplée à des études de terrain.Notre deuxième proposition concerne le processus de conception de tels produits. En effet, plusieurs spécificités sont à prendre en compte en comparaison d’une activité de conception classique : récupération du produit en fin d’usage, applications ultérieures pas ou peu définies, besoins flous, usage influençant les performances, etc. Une étape de conception pour les produits repurposés devra donc être intégrée en amont du processus de repurposing afin d’optimiser les solutions ultérieures. En complément, plusieurs recommandations pour la conception d’un produit repurposé sont formulées. Intégrées au plus tôt, elles visent à faciliter la réutilisation des produits en tenant compte des parties-prenantes, des phases du cycle de vie, des aspects temporels et en gérant mieux l’information.Enfin, un cadre générique structurant la réalisation d’analyses du cycle de vie de ces solutions est proposé. Les ACVistes pourront ainsi plus facilement tenir compte des spécificités de ces stratégies, car la complexité des modélisations ACV pour les produits aux applications en cascade nécessite davantage de rigueur et de précision que pour des produits à application unique. Pour supporter ce cadre, trois recommandations à destination des équipes de conception sont émises. Elles permettent la formalisation d'éléments de contexte pour améliorer la comparaison avec d’autres études et d’informations en vue des analyses de sensibilité.Ces trois propositions sont implémentées sur deux cas d’étude ‘batterie’, au cours de séances de travail regroupant des parties-prenantes de l’ensemble du cycle de vie : commanditaire, équipes de conception, logisticiens, recycleur, etc. / This PhD dissertation focuses on an innovative end-of-life strategy: repurposing. We define ‘repurposing’ as a manufacturing process through which products nearing their end-of-life are reused in different applications. At the end of their intended use, products are reintegrated into the manufacturing chain and adapted for their next application. We also refer to this strategy as cascading application reuse (CAR). The main purpose of CAR is the preservation of the added-value of such products. This strategy is in line with other reuse strategies such as direct reuse and remanufacturing.The central illustration in our case study addresses lithium-ion batteries used in electric vehicles, which are recycled when the battery’s charging capacity falls below 80%. Extending the component lifespan with a second application, e.g. stationary application, postpones introduction into the waste stream, retaining the added-value from the original manufacturing process. Despite these advantages, examples of product adaptation for CAR remain at a proof-of-concept scale - currently these products and their value chains are not yet designed with strategies supporting reuse.The objective of this research is to provide a clear vision to design teams about repurposing strategies, how to integrate the strategies during the upstream stages of the design process and how to facilitate the corresponding lifecycle assessment. The objective is to support designers during the manufacturing of repurposed products. We make three proposals.The first consists of classifying the characteristics specific to the repurposing strategy according to three axes: the product, the (re)manufacturing process and the business model. Through this framework, we describe the dimensions and characteristics of what the repurposed product offers, which are integral during the design activity. These attributes are the result of a study of the relevant literature coupled with several field investigations.Our second proposal concerns the design process for such products. Indeed, several differences with classical design practices appear: the need for product recovery at the end of use, subsequent applications and needs not fully defined, which affect performance, etc. A design stage for repurposed products must therefore be integrated before subsequent applications in order to optimise redesign solutions. Integrated as early as possible, they aim to facilitate product reuse by taking into account stakeholders, life cycle phases, time aspects and better information management.Finally, a generic framework structuring the carrying out of life cycle analyses of repurposing is proposed. This will simplify the inclusion of their specificities for life cycle assessments (LCA) practitioners. Indeed, the complexity of LCA modelling for cascading applications products requires more rigour and precision than single application products. To support this framework, three recommendations for design teams are made, the objective of which is to better formalise the information from the design process. These recommendations support the formalisation of contextual elements to improve comparison with other studies and the organisation of information for sensitivity analyses.These three proposals are implemented on two battery case studies, during working sessions involving stakeholders representing the complete life cycle: sponsor, design teams, logisticians, recycler, etc.

<p>Currently, our world is getting more and more connected: information flows are everywhere at anytime. We are only at the beginning of the communication era. However, few want to know how those data are delivered as long as they are well delivered. Which paths they take, using optical fibres or regular copper cables, such questions do not matter for end-customers.</p><p>As a part of a telecommunication company, these questions do really matter. As networks become increasingly complex, it is significant to keep them under control and make them reliable to deliver high-quality services to users.</p><p>One of our main problems is how to get a representation of this network. More precisely how to get a relevant image of elements that compose this huge web and what points are significant in order to increase the quality of offered services. This thesis will try to answer these questions.</p>

There is a growing interest in investigating the high order contingency events that may result in large blackouts, which have been a great concern for power grid secure operation. The actual number of high order contingency is too huge for operators and planner to apply a brute-force enumerative analysis. This thesis presents a heuristic searching method based on particle swarm optimization (PSO) and tabu search to select severe high order contingencies. The original PSO algorithm gives an intelligent strategy to search the feasible solution space, but tends to find the best solution only. The proposed method combines the original PSO with tabu search such that a number of top candidates will be identified. This fits the need of high order contingency screening, which can be eventually the input to many other more complicate security analyses. Reordering of branches of test system based on severity of N-1 contingencies is applied as a pre-processing to increase the convergence properties and efficiency of the algorithm. With this reordering approach, many critical high order contingencies are located in a small area in the whole searching space. Therefore, the proposed algorithm tends to concentrate in searching this area such that the number of critical branch combinations searched will increase. Therefore, the speedup ratio is found to increase significantly. The proposed algorithm is tested for N-2 and N-3 contingencies using two test systems modified from the IEEE 118-bus and 30-bus systems. Variation of inertia weight, learning factors, and number of particles is tested and the range of values more suitable for this specific algorithm is suggested. Although illustrated and tested with N-2 and N-3 contingency analysis, the proposed algorithm can be extended to even higher order contingencies but visualization will be difficult because of the increase in the problem dimensions corresponding to the order of contingencies.

Currently, our world is getting more and more connected: information flows are everywhere at anytime. We are only at the beginning of the communication era. However, few want to know how those data are delivered as long as they are well delivered. Which paths they take, using optical fibres or regular copper cables, such questions do not matter for end-customers. As a part of a telecommunication company, these questions do really matter. As networks become increasingly complex, it is significant to keep them under control and make them reliable to deliver high-quality services to users. One of our main problems is how to get a representation of this network. More precisely how to get a relevant image of elements that compose this huge web and what points are significant in order to increase the quality of offered services. This thesis will try to answer these questions.