Ces méthodes ont pour but commun l'étude des transitions de phase sous l'aspect analytique de singularités de fonctions. On présente les modèles discrets à spins d'Ising qui servent de support à ce travail. Les fonctions d'énergie de la physique statistique sont alors étudiées dans un contexte général d'approximations de singularités de fonctions convexes. Autour de la notion de matrice de transfert sont élaborées des propriétés de localisation de racines de polynômes. On termine par l'élaboration d'algorithmes de calcul formel de quelques fonctions fondamentales de la physique statistique: fonction de partition, énergie libre. On donne un panorama assez vaste des résultats obtenus à l'aide de ces algorithmes

Nous présentons d'abord les théorèmes du No Free Lunch en nous basant sur le papier de D.H. Wolpert et W.G. Macready (version IEEE 1997) mais aussi les multiples réactions que ces résultats ont provoquées dans la communauté de l'optimisation. Convaincus dès lors de l'intérêt d'une approche globale des problèmes et de la nécessité de la recherche de propriétés générales - et spécialement des invariances par symétries -, nous tentons ensuite de mettre en oeuvre cette méthode dans le cadre de la coloration de graphes simples et non orientés. Ce champ est retenu en raison de son intérêt propre, mais aussi pour son caractère de modèle fécond dans de multiples problèmes d'optimisation. Nous faisons émerger la notion de décomposition d'un graphe en cliques maximales et celle de suites constructives qui permettent de reconstruire un graphe à partir de ses composants élémentaires (primary cliques), véritables équivalents des nombres premiers pour les entiers naturels. Nous produisons un algorithme principal et en étudions deux cas singuliers; ensemble ils fournissent une partition de l'ensemble des colorations valides du graphe étudié. Par suite nous retrouvons le polynôme chromatique de manière formelle, indépendamment du nombre de couleurs disponibles. Nous établissons une correspondance de Galois entre colorations valides et sous-graphes engendrés par des familles emboîtées de cliques maximales pourvu qu'elles soient des décompositions complètes de sous-graphes croissants du graphe total.

Le sulfure de Nickel (NiS) peut former des inclusions dans les verres trempés conduisant à une frac-ture due à la transformation de phase avec changement de volume. Un traitement thermique, provo-quant cette transformation de phase, est actuellement utilisé afin de réduire cet effet. Pour proposer des traitements plus efficaces, une étude allant des mécanismes de transformation jusqu'à la modéli-sation a été menée. Selon la composition et la température, deux mécanismes de transformation (avec ou sans partition) ont été mis en évidence par l'étude microstructurale et calorimétrique donne les lignes directrices de la modélisation. Une étude in situ en microscope optique a fourni les informa-tions complémentaires indispensables (taux de germination, mobilité des interfaces) pour construire des modèles cinétiques. La modélisation décrit la transformation en condition isotherme pourra être adaptée aux conditions anisothermes proches du traitement industrie

<p>This thesis focuses on the territorial dimension of democracy by studying the division of Swedish municipalities. It consists of two parts focusing on two types of changes to the division of municipalities: amalgamation and secession.</p><p>The consequences of a series of amalgamation reforms are the starting point for the first part. The question is if the new structure of the municipalities following from amalgamation, e.g. increased size, changed centre-periphery relations and an increased number of urban areas within municipalities, has had any importance for local democracy. The structural factors are looked at in the light of three aspects of democracy: municipalities as community units, their democratic legitimacy and political participation. This study shows that amalgamations can have negative effects for democracy and the conclusion is that the optimal division, from a democratic point of view, is one of small municipalities with only one dominating urban area in each municipality.</p><p>As for secession, the study shows that few citizens want their part of the municipality to secede, except for those who live in parts that have had an application for secession rejected in recent years. The most important reason for supporting secession is that it would improve democracy. The main reason for opposing secession is that it would lead to decreased efficiency. The study also shows that certain conditions may change the attitude to secession, but these conditions cannot explain why a higher proportion than average is positive to secession in municipality parts that have applied for secession in recent years.</p>

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This thesis focuses on the territorial dimension of democracy by studying the division of Swedish municipalities. It consists of two parts focusing on two types of changes to the division of municipalities: amalgamation and secession. The consequences of a series of amalgamation reforms are the starting point for the first part. The question is if the new structure of the municipalities following from amalgamation, e.g. increased size, changed centre-periphery relations and an increased number of urban areas within municipalities, has had any importance for local democracy. The structural factors are looked at in the light of three aspects of democracy: municipalities as community units, their democratic legitimacy and political participation. This study shows that amalgamations can have negative effects for democracy and the conclusion is that the optimal division, from a democratic point of view, is one of small municipalities with only one dominating urban area in each municipality. As for secession, the study shows that few citizens want their part of the municipality to secede, except for those who live in parts that have had an application for secession rejected in recent years. The most important reason for supporting secession is that it would improve democracy. The main reason for opposing secession is that it would lead to decreased efficiency. The study also shows that certain conditions may change the attitude to secession, but these conditions cannot explain why a higher proportion than average is positive to secession in municipality parts that have applied for secession in recent years.

The compositional technique of cross partitioning is one of Luigi Dallapiccola's most used twelve-tone devices. Through a detailed analysis of three contrapuntal canonic movements from Dallapiccola's Quaderno Musicale di Annalibera, I examine his use of cross partitioning as a motivic tool and as a referential collection. The development of the BACH motive and the derivation of tone-row statements reflects on Dallapiccola's extensive use of cross partitioning and his compositional principles used to achieve a sense of polarity. Upon a preliminary analysis based on set-theory analysis set out by Joseph Straus I draw an interpretive analysis through Alegant's cross partitioning model as well as develop my own set of parameters for interpretation in regards to polarity which is based on intervallic stability.

The study and recognition of graph families (or graph properties) is an essential part of combinatorics. Graph colouring is another fundamental concept of graph theory that can be looked at, in large part, as the recognition of a family of graphs that are colourable according to certain rules. In this thesis, we study additive induced-hereditary families, and some generalisations, from a colouring perspective. Our main results are: · Additive induced-hereditary families are uniquely factorisable into irreducible families. · If <i>P</i> and <i>Q</i> are additive induced-hereditary graph families, then (<i>P</i>,<i>Q</i>)-COLOURING is NP-hard, with the exception of GRAPH 2-COLOURING. Moreover, with the same exception, (<i>P</i>,<i>Q</i>)-COLOURING is NP-complete iff <i>P</i>- and <i>Q</i>-RECOGNITION are both in NP. This proves a 1997 conjecture of Kratochvíl and Schiermeyer. We also provide generalisations to somewhat larger families. Other results that we prove include: · a characterisation of the minimal forbidden subgraphs of a hereditary property in terms of its minimal forbidden induced-subgraphs, and <i>vice versa</i>; · extensions of Mihók's construction of uniquely colourable graphs, and Scheinerman's characterisations of compositivity, to disjoint compositive properties; · an induced-hereditary property has at least two factorisations into arbitrary irreducible properties, with an explicitly described set of exceptions; · if <i>G</i> is a generating set for <i>A</i> &#959; <i>B</i>, where <i>A</i> and <i>B</i> are indiscompositive, then we can extract generating sets for <i>A</i> and <i>B</i> using a <i>greedy algorithm</i>.

Arsenic and antimony are important trace elements in magmatic-hydrothermal systems, geothermal systems and epithermal deposits, but their partitioning behavior between melt and aqueous fluid is not well understood. The partitioning of arsenic and antimony between aqueous fluid and granitic melt has been studied in the system SiO2-Al2O3-Na2O-K2O-H2O at 800 degree C and 200 MPa. The partition coefficients of As and Sb between aqueous fluid and melt, are 1.4 +- 0.5 and 0.8 +- 0.5, respectively. The partitioning of As is not affected by aluminum saturation index (ASI) or SiO2 content of the melt, or by oxygen fugacity under oxidized conditions (log fO2 > the nickel-nickel oxide buffer, NNO). The partitioning of Sb is independent of and SiO2 content of the melt. However, aluminum saturation index (ASI) does affect Sb partitioning and Sb partition coefficient for peralkaline melt (0.1 +- 0.01) is much smaller than that for metaluminous melts (0.8 +- 0.4) and that for peraluminous melts (1.3 +- 0.7). Thermodynamic calculations show that As(III) is dominant in aqueous fluid at 800 degree C and 200 MPa and XPS analysis of run product glass indicate that only As(III) exists in melt, which confirms the finding that does not affect As partitioning between fluid and melt. XPS analysis of run product glass show that Sb(V) is dominant in melt at oxidized conditions (log fO2 > -10). The peralkaline effect only exhibits on Sb partitioning, not on As partitioning at oxidized conditions, which is consistent with the x-ray photoelectron spectroscopy (XPS) measurements that As(III) and Sb(V) are dominant oxidation states in melt under oxidized conditions, because the peralkaline effect is stronger for pentavalent than trivalent cations. Permeable reactive barriers (PRBs) are an alternative technology to treat mine drainage containing sulfate and heavy metals. Two column experiments were conducted to assess the suitability of an organic carbon (OC) based reactive mixture and an Fe0-bearing organic carbon (FeOC) based reactive mixture, under controlled groundwater flow conditions. The organic carbon (OC) column showed an initial sulfate reduction rate of 0.4 μmol g(oc)-1 d-1 and exhausted its capacity to promote sulfate reduction after 30 pore volumes (PVs), or 9 months of flow. The Fe0-bearing organic carbon (FeOC) column sustained a relative constant sulfate reduction rate of 0.9 μmol g(oc)-1 d-1 for at least 65 PVs (17 months). The microbial enumerations and isotopic measurements indicate that the sulfate reduction was mediated by sulfate reducing bacteria (SRB). The cathodic production of H2 by anaerobic corrosion of Fe probably is the cause of the difference in sulfate reduction rates between the two reactive mixtures. Zero-valent iron can be used to provide an electron donor in sulfate reducing PRBs and Fe0-bearing organic carbon reactive mixture has a potential to improve the performance of organic carbon PRBs. The δ34S values can be used to determine the extent of sulfate reduction, but the fractionation is not consistent between reactive materials. The δ13C values indicate that methanogenesis is occurring in the front part of both columns. Arsenic and antimony in groundwater are great threats to human health. The PRB technology potentially is an efficient and cost-effective approach to remediate organic and inorganic contamination in groundwater. Two column experiments were conducted to assess the rates and capacities of organic carbon (OC) PRB and Fe-bearing organic carbon (FeOC) PRB to remove As and Sb under controlled groundwater flow conditions. The average As removal rate for the OC column was 13 nmole day-1 g-1 (dry weight of organic carbon) and its removal capacity was 11 μmole g-1 (dry weight of organic carbon). The remove rate of the FeOC material was 165 nmole day-1 g-1 (dry weight of organic carbon) and its minimum removal capacity was 105 mole g-1 (dry weight of organic carbon). Antimony removal rate of the OC material decreases from 8.2 to 1.4 nmole day-1 g-1 (dry weight of organic carbon) and its removal capacity is 2.4 μmole g-1 (dry weight of organic carbon). The minimum removal rate of FeOC material is 13 nmole day-1 g-1 (dry weight of organic carbon) and its minimum removal capacity is 8.4 μmole g-1 (dry weight of organic carbon). The As(III) : [As(III)+As(V)] ratio increased from 1% in the influent to 50% at 5.5 cm from the influent end, and to 80% at 15.5 cm from the influent end of the OC column. X-ray absorption near edge spectroscopy (XANES) shows As(III)-sulfide species on solid samples. These results suggest that As(V) is reduced to As(III) both in pore water and precipitate as As sulfides or coprecipitate with iron sulfides. The arsenic reduction rate suggests that As(V) reduction is mediated by bacterial activity in the OC column and that both abiotic reduction and bacterial reduction could be important in FeOC.

The study and recognition of graph families (or graph properties) is an essential part of combinatorics. Graph colouring is another fundamental concept of graph theory that can be looked at, in large part, as the recognition of a family of graphs that are colourable according to certain rules. In this thesis, we study additive induced-hereditary families, and some generalisations, from a colouring perspective. Our main results are: · Additive induced-hereditary families are uniquely factorisable into irreducible families. · If <i>P</i> and <i>Q</i> are additive induced-hereditary graph families, then (<i>P</i>,<i>Q</i>)-COLOURING is NP-hard, with the exception of GRAPH 2-COLOURING. Moreover, with the same exception, (<i>P</i>,<i>Q</i>)-COLOURING is NP-complete iff <i>P</i>- and <i>Q</i>-RECOGNITION are both in NP. This proves a 1997 conjecture of Kratochvíl and Schiermeyer. We also provide generalisations to somewhat larger families. Other results that we prove include: · a characterisation of the minimal forbidden subgraphs of a hereditary property in terms of its minimal forbidden induced-subgraphs, and <i>vice versa</i>; · extensions of Mihók's construction of uniquely colourable graphs, and Scheinerman's characterisations of compositivity, to disjoint compositive properties; · an induced-hereditary property has at least two factorisations into arbitrary irreducible properties, with an explicitly described set of exceptions; · if <i>G</i> is a generating set for <i>A</i> &#959; <i>B</i>, where <i>A</i> and <i>B</i> are indiscompositive, then we can extract generating sets for <i>A</i> and <i>B</i> using a <i>greedy algorithm</i>.