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We are facing the problems of climate change, the unfair share and over use of Earth’s resources. Global North overuses, Sweden has an ecological footprint of four planets. The challenge is to change our lifestyles. This thesis is trying out a method to diffuse ideas of sustainable development (SD) and for citizen participation. I created a future vision of a sustainable neighborhood inspired by Jane Jacobs and the concept of densification. This I presented to three homogenous focus groups: the next-door neighborhood, home owners and people in rentals. Free discussion then followed, and then a questionnaire. The findings where that the participants, fifteen of sixteen, thought the method gave them new ideas, allowed them to share their knowledge, and that it was a good method for participation. I thought that it was a ‘fun’ method. Focus groups research works more the way people normally interact, as did the literature show. I could see the learning process, that Patsy Healey describes, the creation of cultures, and also how the issue of SD was explored. It was time consuming to recruit participants. The tendency was that volunteers liked to talk, had an interest in planning, although not all in favor of SD. Many resembled me, in age and cultural background. The method could be useful to deepen dialog with citizens, especially in an early stage of planning. The vision should be ‘daring’ to spur good discussions, that may land in a compromise on SD. / Vi står inför klimatförändringar, den ojämna fördelningen och överanvändningen av jordens resurser. Nord överanvänder, Sverige har ett ekologiskt fotavtryck på fyra planeter. Utmaningen är att ändra vår livsstil. Denna uppsats prövar en metod för att sprida idéer om hållbar utveckling och för medborgardeltagande. Jag skapade en vision för ett hållbart grannskap inspirerad av Jane Jacobs och begreppet förtätning. Denna presenterade jag för tre homogena fokusgrupper: de i närmsta grannskapet, de som ägde sitt boende och de som hyrde. Sedan följde fri diskussion och sedan en enkät. Resultatet blev att deltagarna, femton av sexton, tyckte att metoden gav dem nya idéer, tillät dem att dela sina kunskaper och att det var en bra metod för deltagande. Jag tyckte att det var en ’rolig’ metod. Forskning med fokusgruppers fungerar mer som man vanligen umgås, vilket även litteraturen visade. Jag kunde se lärandeprocessen, som Patsy Healey beskriver, skapandet av kulturer och också hur begreppet hållbar utveckling undersöktes. Det var tidskrävande att rekrytera deltagare. Tendensen var att de frivilliga gillade att prata, var intresserade av planering, men inte alla positiva till hållbar utveckling. Många påminde om mig, i ålder och kulturell bakgrund. Metoden kan vara användbar till att fördjupa dialogen med medborgare, speciellt i ett tidigt stadie av planering. Visionen ska vara ’vågad’ för att sätta igång bra diskussioner och landa i en kompromiss i hållbar utveckling.

Une méthode de couplage continu-discret a été développée pour simuler les mécanismes complexes d'endommagement de la silice soumise à un choc laser de haute puissance. Dans un premier temps, une classification des méthodes numériques existantes a été faite pour choisir celles les mieux adaptées à la simulation du comportement sous choc de la silice. Comme résultat de cette classification, deux méthodes ont été retenues: la méthode des éléments discrets (DEM) et la méthode des éléments naturels contraints (CNEM). Ces méthodes sont alors couplées en se basant sur la technique dite "Arlequin". Puis, un modèle numérique permettant de tenir compte des différents phénomènes qui caractérise le comportement de la silice sous haute pression a été développé. Pour bien caractériser les mécanismes de fissuration de la silice à l’échelle microscopique, un nouveau modèle de rupture a été développé dans ce travail. Finalement, ces deux modèles, modèle de comportement et modèle de rupture, ont été intégrés dans la méthode du couplage pour simuler d'un point de vue mécanique le choc laser sur un échantillon en silice. / A discrete-continuum coupling approach has been developed to simulate the laser-induced damage in silica glass. First, a classification of the different numerical methods has been performed to select the ones that best meet the objectives of this work. Acting upon this classification, the Discrete Element Method (DEM) and the Constrained Natural Element Method (CNEM) have been retained. Subsequently, a coupling approach between these methods has been proposed. This approach is based on the Arlequin technique. In the second part, a numerical model of the silica glass mechanical behavior has been developed to better characterize the silica glass response under highly dynamic loadings and particularly loading generated by a laser beam. To correctly characterize the silica glass cracking mechanisms, a new fracture model has been proposed in this work. Finally, all these developments have been used to simulate the laser-induced damage in silica glass.

L’évolution des lois relatives à l’utilisation de produits biocides impose d’étudier des méthodes innovantes de traitement du bois. Dans ce contexte, les travaux de recherche présentés s’intéressent à une nouvelle alternative dite « non-biocide » impliquant la fabrication de composites bois massif / polymères obtenus par imprégnation de monomères et polymérisation in situ provoquée par chauffage. Le méthacrylate de méthyle, quatre acrylates organiques et trois acrylates hydrosolubles, ainsi que l’alcool furfurylique ont été testés. Les composites fabriqués ont été caractérisés : le polymère est bien présent dans le bois et il peut être résistant au lessivage à l’eau. Le bois a été densifié, les composites sont alors moins hydrophiles et plus stables dimensionnellement ; les propriétés mécaniques sont améliorées. Le traitement peut induire une durabilité conférée élevée. Parallèlement, une méthode d’imprégnation innovante a été testée : l’imprégnation axiale. Ce procédé consiste en l’imprégnation basse pression de billons de bois vert par une solution de traitement transitant via les voies naturelles de circulation de la sève. Des billons ont été imprégnés avec une solution de cuivre, dosé ultérieurement afin de s’assurer de la bonne répartition du produit dans le bois ; cela a permis la validation du procédé d’imprégnation axiale pour le hêtre, le charme et le bouleau. Enfin, des composites ont été fabriqués par imprégnation axiale de solutions aqueuses polymérisables à base d’alcool furfurylique ; ils sont résistants à la lixiviation à l’eau et moins hydrophiles que le bois naturel. Leur durabilité face aux champignons lignivores est améliorée, particulièrement dans le cas du traitement le plus concentré / The evolution of laws on the use of biocide products makes it necessary to explore innovative methods of treating wood. In this context, the presented research focuses on a new alternative called a "non-biocide" treatment method involving the manufacture of solid wood-polymer composites obtained by impregnation of monomers and in situ polymerization caused by heating. Methyl methacrylate, four organic acrylates and three water-soluble acrylates, and furfuryl alcohol were tested. Composites manufactured were characterized: the polymer is present in the timber and may be resistant to leaching in water. Wood has been densified, while the composites are less hydrophilic and more dimensionally stable; the mechanical properties are improved. Treatment can induce high durability. Otherwise, an innovative method of impregnation was tested: axial impregnation. This process consists in the low-pressure impregnation of green wood ridges by treatment solution transiting via natural pathways of sap circulation. Ridges were impregnated with a copper solution, later determined to ensure good distribution of the product in the timber; this allowed the validation of the axial impregnation method for beech, hornbeam and birch. Finally, the composites were produced by axial impregnation of polymerizable aqueous solutions based on furfuryl alcohol; they are resistant to water leaching and less hydrophilic than the original wood. Their durability in the presence of wood-destroying fungi is improved, particularly in the case of the more concentrated treatment

L'objectif de ce travail de thèse consistait à développer d'une technologie de mise en forme de poudres d'aciers faiblement alliés nitrurées afin d'introduire le nitrure ε-Fe2-3N dans la masse de la pièce mécanique.Pour atteindre cet objectif, deux voies ont été étudiées :- réaliser des pièces frittées à partir de poudre d'acier nitrurée ou nitrurée-enrobée (contenant une teneur importante en nitrure ε),- nitrurer et densifier une poudre d'acier pendant l'étape de frittage.La nitruration d'une poudre d'acier 4140 lors du frittage en CIC s'est avérée insuffisante vis-à-vis des teneurs en nitrure ε nécessaires pour l'application industrielle.L'étude de la stabilité, en CIC, de la poudre d'acier 4140 nitrurée a démontré la conservation des nitrures γ' et ε en grande proportion jusqu'à des températures de 650°C, quel que soit la nature du cycle de CIC appliqué. L'étude de la stabilité, à 600°C, de poudres d'acier nitrurées placées en capsules scellées a montré une légère dénitruration de ces poudres pendant le traitement.Des essais de densification de ces poudres d'acier nitrurées ont ensuite été réalisés par frittage SPS puis CIC. Afin de densifier les particules d'acier nitrurées, nous avons choisi d'utiliser un liant. Les essais de frittage SPS ont permis de mettre en évidence les paramètres expérimentaux les plus pertinents pour l'obtention d'un matériau dense et comportant le nitrure ε, et de proposer des préconisations sur les compositions acier-liant. Ces compositions ont été testées en CIC avec succès. Deux d'entre elles ont ainsi permis l'obtention de matériaux denses aux propriétés tribologiques et mécaniques satisfaisantes pour l'application industrielle. / The aim of this Ph.D thesis was to develop a technology to shape nitrided low-alloyed steels powders to introduce the ε-Fe2-3N nitride in the volume of the mechanical component.To achieve this goal, two approaches were considered:- the sintering of coated nitrided steel powder or nitrided steel powder (containing a high content of ε nitride),- the simultaneous densification and nitriding of low-alloy steel powder during the sintering step.Nitriding 4140 steel powder during hot isostatic pressing (HIP) does not allow producing sufficient ε-phase content for industrial application.The stability study of nitrided 4140 steel powder during HIP shows that a huge proportion of nitrides (γ' and ε) is conserved at 650°C, regardless of the HIP cycle. The stability study, at 600°C, of nitrided steel powders placed in sealed evacuated glass tubes, shows a slight denitriding of these powders during the process.Thus, densification of these nitrided steel powders was made by spark plasma sintering (SPS) and HIP. To densify the nitrided steel particles, we have used a copper-phosphorous binder. From SPS experiments, we have deduced the most relevant experimental parameters to obtain a dense material containing ε-phase, and we have proposed recommendations on the composition of nitrided steel-binder mixture. The identified compositions were successfully sintered by HIP. Two of them allow obtaining dense materials with interesting tribological and mechanical properties for industrial application.

Public urban green spaces are crucial parts of cities due to the many connections existing between urban greenery and well-being. Additionally, public urban green space represents a wide range of spatial concepts, such as parks, urban forests, commons, in-between-spaces, and gardens. This study explores challenges for contemporary public urban green space in an increasingly urban world, with high demands on urban growth, and simultaneously the need for more sustainable societies and cities. The aim is to problematize the complex reality for contemporary public urban green space from an urban planning perspective in times of urban densification strategies, global competitiveness between cities and trends of ‘re-naturing’.   The scope of this thesis is based on four high profile case studies. The Green Walkable City in Stockholm and The Green Living Spaces in Birmingham constitute planning strategies with a holistic approach to urban green space, including a strong focus on well-being. The High Line in New York and Parklets in San Francisco represent urban green space concepts, influential both at the local level and in the larger urban planning debate. The results point to a need to acknowledge the complexity inherent to urban green space provision, design, and management. This study contributes with insights of direct connections between narratives of nature, materialized urban greenery projects and conceptualizations of functionality of nature in urban planning projects. From the post-industrial, pristine flirting, crafted wilderness of the High Line; a symbolic but cosmetic scrambling with planters and narratives of parks of parklets; dualistic argumentations of natural values connected to quality over quantity of nature in a densifying and growing Stockholm; to pragmatic yet emotional and ambitious conceptualizations of human nature in biohilic urbanism and green space planning in Birmingham. Gentrification, publicness and production of public space and densification strategies are central themes in urban studies – and public urban green space can play an active role in these processes. / <p>QC 20160518</p>

Det är allmänt känt att det sker en kontinuerlig ökning av världens befolkning och följden av detta är att städer växer kraftigt. Det medför en förtätning i stadskärnan och som en konsekvens sker en konflikt mellan grönstrukturen och nybyggnationer. Varje kommun strävar efter tillväxt och balansen för hållbar tillväxt är subtil och det är här intresset för uppsatsen grundar sig.  Uppsatsens syfte är att undersöka hur stor plats grönstrukturen får i planeringen av Karlstads stadskärna. För att besvara syftet studeras förtätningens olika utmaningar, samt hur ekocentrism och antropocentrismens etiska synsätt uttrycks i planeringen. Synsätten skapar en förståelse för hur och för vem stadsrummet planeras för. Det finns en skildring i planeringen där antropocentrismen under en längre tid kritiseras av ekocentrismen. Det har genomförts en kvalitativ metod för att besvara syftet och frågeställningarna. En dokumentanalys har utförts, samt en gruppintervju med representanter från Karlstads kommun. Resultatet om grönstrukturen i centrum visar sig ha många likheter mellan de olika metoderna, vilket ökar uppsatsens trovärdighet. I samband med att staden förtätas minskar gaturummet och det leder till att det skapas en konflikt mellan olika aktörers intressen för platsens användning. Aktörer har ett stort intresse av en hög ekonomisk tillväxt och det innebär att grönskan värderas lägre i planeringen mot en hållbar stadsutveckling till skillnad från bostäder, verksamheter och parkeringsplatser. Grönstrukturen saknar riktlinjer i planeringen, vilket gör att grönskan är svår att motivera när samhällsplaneringen styrs av en antropocentrisk syn. Sammanfattningsvis skapar det svårigheter när grönstrukturens plats ska motiveras i Karlstads växande stad. / It´s commonly known that there is a continuous increase of the world´s population and the consequence of this is that cities are growing rapidly. This means a densification in the center of the city and a consequence of this is a conflict between the green structure and the new construction. Each city seeks for growth and the balance for sustainable development is subtle and this is where the essay found its interest.  The purpose of the essay is to look over how big influence the green structure gets in the planning of Karlstads city. In order to answer the purpose, the various challenges of the densification are studied, as well as how ecocentrism and anthropocentrism ethical approach is expressed in the planning. The approach creates an understanding of how and for whom the urban space is planned. There is a depiction in the planning where anthropocentrism has long been criticized by ecocentrism. A qualitative method has been implemented to answer the purpose and the questions. A document analysis has been performed, as well as a group interview with representatives from Karlstads kommun. The result of the green structure in the city proves to have many similarities between the different methods, which increases the credibility of the essay. In connection with the city being densified, the street space decreases and this leads to a conflict being created between the various developers interests for the use of the space in the city. Developers have an interest in high economic growth and this means that the greenery is valued lower in the planning for sustainable urban development, unlike housing, businesses and parking spaces. The green structure lacks guidelines in the planning, which means that the greenery is difficult to justify when the planning of society is governed by an anthropocentric view. In summary, it creates difficulties when the location of the green structure must be motivated in Karlstad's growing city.

[pt] O estudo a respeito de homojunções e heterojunções se apresenta como de grande interesse científico e tecnológico, pois os mecanismos de formação e de atuação dessas estruturas ainda não são plenamente conhecidos. Essas junções estão na base de diferentes tecnologias, tais como, diodos, transistores, capacitores e supercapacitores, varistores, células fotovoltaicas, detectores de luz UV, diversos tipos de sensores, catalisadores e fotocatalisadores, entre outros. A presente tese de doutorado visa contribuir para o desenvolvimento de sistemas cerâmicos policristalinos (micro e nanoestruturados) à base de ZnO e SnO2 e para a compreensão dos mecanismos de formação das homojunções e heterojunções presentes nesse sistema material e suas relações com o comportamento varistor, em termos da estabilidade e degradação dessas junções. Microscopia eletrônica de varredura, espectroscopia de raios-X por dispersão de energia e difração de raios-X foram utilizadas para a caracterização microestrutural. Análises térmica e dilatométrica foram utilizadas para a determinação dos parâmetros e mecanismos de densificação e sinterização que dão origem às junções consideradas. Para a determinação das características elétricas foi utilizada a análise de capacitância e levantamento das curvas de polarização. Em função das composições químicas avaliadas foram obtidas microestruturas composta por homojunções e heterojunções, com diferentes níveis de densificação e características varistoras, ou seja, comportamento não-linear entre tensão e corrente elétrica, com tensões de chaveamento de diferentes magnitudes, permitindo relacionar o comportamento eletrotérmico dos varistores com as características das homojunções e heterojunções consideradas. / [en] The study about homojunctions and heterojunctions has scientific and technological value, because the mechanisms of formation and performance of these structures are not fully known. These junctions are in the base of different technologies, such as diodes, transistors, capacitors and supercapacitors, varistors, photovoltaic cells, detector of UV light, many kinds of sensors, catalysts and photocatalysts, among others. The present thesis aims to contribute to the development of polycrystalline ceramic systems (micro and nanostructured) based on ZnO and SnO2 and to the understanding ofthe mechanisms of formation of homojunctions and heterojunctions present in these systems and their relations with the varistor behavior, in terms of stability and degradation. Scanning electron microscopy, X-ray energy dispersive spectroscopy and X-ray diffraction were used to the microstructural characterization. Thermal and dilatometric analyses were used to determine the parameters and mechanisms of densification and sintering that give rise to the junctions considered. For the determination of the electrical characteristics, analysis of capacitance and polarization curves were used. Depending on the chemical compositions a variely of microstructures were obtained containing homojunctions and heterojunctions, with different densification levels and distinct varistors characteristics, that it, nonlinear behavior between voltage and electric current, with different magnitudes of switching voltages permitting to correlate the electrothermal behavior of varistors with the characteristics of homojunctions and heterojunctions considered.

Made available in DSpace on 2017-07-21T20:42:35Z (GMT). No. of bitstreams: 1 ALEXEYOSA.pdf: 5421732 bytes, checksum: d315c8a952abc240783ef27ca2d03d74 (MD5) Previous issue date: 2011-03-30 / The ceramic materials have great potential for structural applications because of their have excellent mechanical properties, eg, high hardness, high mechanical strength and resistance to aggressive media. However their low toughness and bending resistance, limiting their range of applications and open interest for researchers for better mechanical properties. Inclusions of nanometric particles in ceramic matrix, called nanocomposites, and the control of ceramic processing, by controlling grain size and densification, can be used for produce ceramic products with higher strength and toughness. One method to control the microstructure that has been studied is the two-step sintering, which has been successfully applied for the densification of nanometric and ultra fine ceramic powders without grain growth. In this work, the two-step sintering of nanocomposite of alumina with 5% volume nanoparticles zirconia was studied. Two proposals in two-step of sintering were studied, of which one consisted to heat the nanocomposite to a high temperature and then rapid cool down to a lower temperature sintering, and on the other proposal was made a step at a temperature below the initiation of densification, followed by heating to the maximum densification rate temperature. The sintering temperature for steps were chosen from constant-heating-rate and conventional sintering. The results showed that the two proposals were efficient to control the grain growth and densification in alumina-zirconia nanocomposites, and, with the sintering in twosteps, it was possible to reduce the grain size up to 70% of the grain size of nanocomposite sintered conventionally. / Os materiais cerâmicos apresentam grande potencial para aplicações estruturais, pois possuem excelentes propriedades mecânicas como, por exemplo, alta dureza, alta resistência mecânica à compressão e inércia química. Porém, a sua baixa tenacidade à fratura e baixa resistência à flexão, limitam sua gama de aplicações e gera interesse para estudos em busca de melhores propriedades mecânicas. A inclusão de partículas nanométricas numa matriz cerâmica, que são os chamados nanocompósitos, e o controle do processamento cerâmico, através do controle do tamanho de grão e densificação, podem auxiliar na obtenção de produtos cerâmicos de maior resistência mecânica e tenacidade. Um método de controle da microestrutura que vem sendo estudado é a sinterização em duasetapas, a qual vem sendo aplicada com sucesso para a densificação de pós cerâmicos nanométricos e ultra finos sem crescimento de grãos. Nesse trabalho, foi estudada a sinterização em duas-etapas de nanocompósitos de alumina com 5% em volume de partículas de zircônia nanométrica. Duas propostas de sinterização em duas etapas foram estudadas. Uma consistiu em aquecer o nanocompósito rapidamente a uma alta temperatura e em seguida resfria-lo ao patamar de sinterização; na outra proposta foi feito um patamar de queima numa temperatura abaixo do início do processo de densificação, seguido do aquecimento do nanocompósito até a temperatura de máxima taxa de densificação. As temperaturas para as etapas de sinterização foram escolhidas a partir da sinterização a taxa de aquecimento constante e da sinterização convencional. Os resultados mostraram que a duas propostas estudadas foram eficientes para controlar o crescimento de grãos e a densificação nos nanocompósitos alumina-zircônia, sendo que, com as sinterizações em duas-etapas, foi possível reduzir o tamanho de grão em até 70% do valor do tamanho de grão do nanocompósito sinterizado convencionalmente.

Le changement démographique de Tunis et du Grand Tunis et le développement de l’habitat spontané ont amené la ville de Tunis à être une métropole internationale, avec une zone médiane s’étalant sur 30 km. Partant d’un régime complexe comportant énormément de contraintes structurelles et procédurales, et considérant les limites des politiques foncières poursuivies, l’accès au sol urbain en Tunisie est de plus en plus dépendant des régulations du marché. Le gouvernement tunisien envisage l’étude d'un futur projet de ville nouvelle dans une localité, appelée Fejja, située à vingt cinq kilomètres de la capitale. Ce projet conciliera une zone industrielle et une zone d'habitat dans une dynamique de développement économique et durable. Cette ville nouvelle sera la première ville nouvelle en Tunisie.L’étalement spatial du grand Tunis résulte de plusieurs facteurs parmi lesquels le facteur foncier est stratégique dans la mesure où les lotisseurs clandestins d’une part, les propriétaires fonciers d’autre part, sont à l’origine du développement d’un marché foncier spécifique car destiné aux populations économiquement modestes. En termes de politique d’habitat, l’Etat étant dans l’incapacité de produire une offre foncière adaptée à cette population, tolère le développement en périphérie de ce type d’habitat.Le présent travail de recherche consiste à analyser les différentes phases du processus d'urbanisation de Tunis, et de déterminer les mécanismes sous-jacents qui sous-tendent ce processus, tels que la densification, la péri-urbanisation et les projets d’aménagement du territoire par le biais de la création d’une ville nouvelle. / A combination of demographic changes and the development of informal settlements in Tunis and its surrounding area mean that the city now constitutes what is an international metropolis, with a median zone extending over 30 km. Given the complexity of the system originally in place, with its many structural and procedural constraints, along with the limitations of land policies which have already been pursued, access to urban land in Tunisia is increasingly dependent on market regulation. The Tunisian government is now studying the proposal of a future project of a new town in a locality called Fejja, located approximately thirty-five kilometers from the capital. The first of its kind in Tunisia, this project aims to reconcile an industrial park with a zone of habitat within the dynamics of an economically sustainable and durable development.The urban sprawl of Grand Tunis is the result of a number of factors; one of which being the illegal developers and the landowners. Those factors are responsible for the development of a land market designed specifically for people with low income. In terms of housing policy, the state has so far proved unsuccessful it its attempts to provide a land offer which is suitably adapted to this community. It has thus decided to tolerate such housing developments which are now common to the outskirts of the city. This work consists in analyzing the different phases of the urbanization process of Tunis, and to determine the underlying mechanisms behind this process, such as densification, peri-urban and regional development projects through the creation of a new town.