Dissertations / Theses on the topic 'Formation Los Molles'

Les nannofossiles calcaires représentent un groupe diversifié de fossiles, remontant au Trias supérieur et s'étendant jusqu'à nos jours, caractérisés par leur composition calcaire et une taille inférieure à 30 µm. Parmi eux, les coccolithophoridés, qui constituent la fraction la plus importante du nannoplancton calcaire, c'est-à-dire des algues unicellulaires flagellées typiquement marins appartenant à la sous-classe Calcihaptophycidae, recouvertes de plaques de carbonate de calcium (coccolithes). Les représentants fossiles des coccolithophoridés correspond à leurs restes d'exosquelette, généralement conservés sous une forme désagrégée, comme des coccolithes individuels. Leur présence dans les océans est essentielle, car ils constituent l'un des principaux groupes de producteurs primaires marins. Les données géologiques suggèrent que les coccolithophoridés ont maintenu leurs exigences écologiques presque inchangées au fil du temps, et ainsi nous permettant de reconstruire de manière fiable les conditions paléoenvironnementales, paléobiogéographiques et paléoclimatiques. L'objectif général de cette thèse est d'étudier les associations de nannofossiles calcaires des sédiments marins du Jurassique inférieur-moyen au sud haut structural de Huincul du bassin de Neuquén (Argentine) et de combiner ces informations avec celles déjà disponibles afin d'élargir et d'améliorer les ressources biostratigraphiques du bassin. En comparant ces enregistrements avec des associations de nannofossiles calcaires provenant d'autres endroits du monde, nous visons à établir des corrélations d'âge globales et à évaluer les relations paléobiogéographiques, afin de générer un modèle biostratigraphique local. L'étude se concentre sur des échantillons provenant de trois sections d'affleurement et de deux forages d'exploration. Un total de 102 échantillons de surface et 111 échantillons de subsurface ont été étudiés. En outre, des analyses géochimiques (i.e. les isotopes stables du carbone, la matière organique totale et la composition élémentaire) ont été effectuées sur 384 échantillons d'affleurement. Des techniques de décantation aléatoire et de décantation par gravité ont été utilisées pour traiter les échantillons de nannofossiles. Le degré de similitude entre les associations de nannofossiles a été évalué en effectuant une analyse NMDS et une analyse UPGMA, en utilisant l'indice de similitude de Dice. La pyrolyse et la spectrométrie de masse du rapport isotopique ont été utilisées pour traiter les échantillons en vue de l'analyse de la matière organique totale et des isotopes stables, respectivement. Pour l'analyse élémentaire, la technique de diffraction des rayons X a été utilisée. Quarante-neuf espèces sont ici décrites, répartis dans neuf famillies et une espèce insertae sedis, dont cinq sont reconnues pour la première fois pour le bassin et le Pacifique sud-est. Six biozones et de nombreuses sous-zones sont reconnues en surface et subsurface, et sont en corrélation avec les schémas biostratigraphiques de la région de la Téthys. Elles correspondent au Pliensbachien à l'Aalénien moyen - Bajocien inférieur (NJT4–NJT9). Trois intervalles d'excursions isotopiques négatives accompagnées d'augmentations de la teneur en matière organique sont identifiés. Le premier d'entre eux est considéré comme l'équivalent temporel de le T-OAE. Les autres excursions de grande amplitude enregistrées au Toarcien moyen et dans l'intervalle Toarcien-Aalénien représentent le premier enregistrement de ce type pour l'intervalle Toarcien-Aalénien dans le bassin de Neuquén, et le deuxième enregistrement pour l'hémisphère sud. Les associations de nannofossiles calcaires du Pliensbachien sont liées à celles de la région de Téthys. Le Corridor hispanique est identifié comme la voie de dispersion des nannofossiles calcaires entre les océans Paléo-Pacifique et Téthys au cours du Jurassique inférieur, ce qui indique que son ouverture remonte au moins au début du Pliensbachien
Calcareous nannofossils represent a diverse group of fossils, dating back to the Late Triassic and extending their record to the present day, characterised by their calcareous composition and a size under 30 microns. Among them oustand the coccolithophorids, which constitute the most important fraction of calcareous nannoplankton, i.e. flagellated unicellular algae belonging to the Subclass Calcihaptophycidae, covered by calcium carbonate plates (coccoliths), and typically marine inhabitants of the photic zone. The representation of coccolithophorids in the fossil record corresponds to their exoskeletal remnants, commonly preserved in a disaggregated form, as individual coccoliths. Their presence in the oceans is key as they are one of the main groups of marine primary producers. Evidence from the geological record suggests that coccolithophorids have maintained their ecological requirements almost invariant over time, making them key to reconstruct palaeoenvironmental, palaeobiogeographical and palaeoclimatic conditions. The aim of this thesis is to study the calcareous nannofossil associations of Early-Middle Jurassic marine sediments, south of the Huincul High, Neuquén Basin (Argentina). By combining this information with that already available, we seek to expand and improve the biostratigraphic resources of the basin, determine similarities with assemblages from other regions of the world, and evaluate the response of these organisms to important palaeoenvironmental events. The study focuses on samples from three outcrop sections —named El Matuasto I, II and III— and two exploratory boreholes —YPF.Nq.BCE.x-1 and YPF.Nq.PTU.x-2—. A total of 102 surface samples, 20 core samples and 91 drill cuttings samples were studied. In addition, geochemical analyses (i.e., stable carbon isotopes, total organic matter and elemental composition) were performed on 384 outcrop samples. Random settling and gravity settling techniques were used to process the calcareous nannofossil samples. Quantitative analysis of nannofossils required counting at least 300 individuals; in case of a sample with low abundance, counting stopped at 450 fields of view. The degree of similarity between nannofossil associations was assessed by running NMDS and UPGMA analyses, both using the Dice index. Pyrolysis and isotope ratio mass spectrometry were used to process samples for total organic matter and stable isotope analysis, respectively. For the elemental analysis, the X-ray diffraction technique was executed. In all cases, samples containing shell remains and/or evidence of weathering were avoided. Forty-nine species are described, distributed in nine families and one species insertae sedis, of which five are recognised for the first time for the basin and the southeast Pacific area, and most of them are illustrated. Six biozones and numerous subzones are recognized on the surface and subsurface sections and correlate with biostratigraphic schemes of the Tethys region. These correspond to the Pliensbachian (Biozone NJT4) to the middle Aalenian - early Bajocian (Biozone NJT9). Three intervals of negative isotopic excursions accompanied by increases in organic matter content are identified. Applying the biostratigraphic framework, the first of these is considered to be the time-equivalent of the Toarcian Oceanic Anoxic Event (T-OAE). The other high-amplitude isotope excursions recorded in the middle Toarcian and in the Toarcian-Aalenian interval represent the first record of their kind for the Toarcian - Aalenian interval in the Neuquén Basin, and the second record for the southern hemisphere. The Pliensbachian calcareous nannofossil associations recognized in one of the sections are biogeographically related to those of the Tethys region. The Hispanic Corridor is identified as the pathway of calcareous nannofossil dispersal between the Pacific and Tethys oceans during the Early Jurassic, indicating its time of opening at least from the early Pliensbachian

Cette thèse aborde deux thématiques chères à la matière molle, à savoir, l’apparition d’interaction médiées par le milieu entre objets de taille nanométrique ou micrométrique, et la notion de tension de surface dans les systèmes hors de l’équilibre. La première partie de cette thèse est consacrée à l’étude de systèmes dans lesquelles les interactions entre particules sont médiées par un champ fluctuant. Nous étudions dans un premier temps un système hors d’équilibre et nous montrons que l’existence d’interactions médiées associées à l’activité des particules qui place le système hors de l’équilibre conduit à la formation de structures complexes. Nos prédictions s’appuient sur des méthodes de mécanique statistique mais surtout sur des méthodes de dynamique non-linéaire utilisées pour prédire l’apparition de motifs dans les systèmes dans lesquels il existe une quantité conservée. Le seconde étude de cette partie est dédiée à l’explication des interactions émergentes observées expérimentalement dans des systèmes de particules colloidales insérées dans des phases lamellaires lyotropiques. En partant de la description microscopique des interactions entre particules et couches de surfactants, nous calculons de façon exacte la force effective qui émerge entre particules seulement. Ces résultats analytiques sont ensuite utilisés pour distinguer et identifier, parmi deux types possibles d’interactions entre lamelles et particules, lequel est observé dans notre système expérimental à l’étude. La seconde partie de cette thèse s’attache à identifier la notion de tension de surface dans les fluides actifs. Nous parvenons à proposer une définition de la tension de surface qui relie les forces macroscopiques aux forces microscopiques existant entre particules, ou entre particules et un mur confinant. Lorsque le fluide actif est en contact avec un mur, la tension de surface solide-fluide est en général d’une nature plus complexe que celle que l’on peut définir pour son analogue d’équilibre. Par ceci, nous entendons que la valeur mesurée de la tension de surface peut dépendre de la géométrie ou d’autres détails de l’appareil de mesure utilisé. Nous montrerons également que des appareils de mesure correctement choisis permettent d’accéder à une tension de surface intrinsèque au matériau(et non plus à la géométrie), caractéristique d’une variable d’état d’équilibre. Les séparations de phases de type liquide-vapeur peuvent être également rencontrées dans les assemblées de particules auto-propulsées, lorsque celles-ci sont sujettes à une séparation de phase induite par la motilité. Nous montrons alors que la tension de surface associée à l’interface liquide-vapeur possède une définition mécanique cohérente avec avec son interprétation d’équilibre
This thesis focuses on two topics ubiquitous in soft matter: first, mediated interactions between nano-to-micrometer sized objects, second, surface tension in out-of-equilibrium systems. The first part of this thesis is devoted to the properties of a system of particles whose interactions are mediated by a fluctuating background. We start with a nonequilibrium study and we show that the combination of mediated interactions and of the nonequilibrium drive leads to complex structures. Our predictions, beyond statistical mechanical methods, rest on extending the methods of nonlinear dynamics in pattern forming systems, to systems with a local conservation law. The second study of this part is dedicated to an equilibrium experimental system of colloidal particles embedded in lyotropic lamellar phases. Relying on a bottom-up approach, we implement the details of the interaction between each colloidal particle and each lamella to come up with an exact description of the effective force emerging between colloids. These analytical results are then used to discriminate between two types of interaction, both being possibly encountered in experiments. The second part of this thesis focuses on the notion of surface tension for interfaces involving active fluids. We will come up with a definition relating macroscopic forces to microscopic ones, either between particles or, when applicable, between particles and a confining medium. When the active fluid is in contact with a solid boundary, the solid-fluid surface tension is, in general, a more complex quantity than its equilibrium counterpart. By this we mean that its value may depend on the geometry or other details of the measuring device. We will also show that a carefully designed probe allows us to access an equation-of-state-abiding surface tension akin to its equilibrium counterpart. Liquid-vapor interfaces can also be encountered in assemblies of self-propelled particles when these undergo a motility-induced phase separation. We show also that the surface tension associated to a liquid-vapor interface possesses a mechanical definition that echoes the equilibrium one

Esta tese tem como objetivo principal a proposição de solução para o problema do encaixe de moldes em tecidos listrados da indústria do vestuário. Os moldes são peças com formato irregular que devem ser dispostos sobre a matéria-prima, neste caso o tecido, para a etapa posterior de corte. No problema específico do encaixe em tecidos listrados, o local em que os moldes são posicionados no tecido deve garantir que, após a confecção da peça, as listras apresentem continuidade. Assim, a fundamentação teórica do trabalho abrange temas relacionados à moda e ao design do vestuário, como os tipos e padronagens de tecidos listrados, e as possibilidades de rotação e colocação dos moldes sobre tecidos listrados. Na fundamentação teórica também são abordados temas da pesquisa em otimização combinatória como: características dos problemas bidimensionais de corte e encaixe e algoritmos utilizados por diversos autores para solucionar o problema. Ainda na parte final da fundamentação teórica são descritos o método Cadeia de Markov Monte Carlo e o algoritmo de Metropolis-Hastings. Com base na pesquisa bibliográfica, foram propostos dois algoritmos distintos para lidar com o problema de encaixe de moldes em tecidos listrados: algoritmo com pré-processamento e algoritmo de busca do melhor encaixe utilizando o algoritmo de Metropolis-Hastings. Ambos foram implementados no software Riscare Listrado, que é uma continuidade do software Riscare para tecidos lisos desenvolvido em Alves (2010). Para testar o desempenho dos dois algoritmos foram utilizados seis problemas benchmarks da literatura e proposto um novo problema denominado de camisa masculina. Os problemas benchmarks da literatura foram propostos para matéria-prima lisa e o problema camisa masculina especificamente para tecidos listrados. Entre os dois algoritmos desenvolvidos, o algoritmo de busca do melhor encaixe apresentou resultados com melhores eficiências de utilização do tecido para todos os problemas propostos. Quando comparado aos melhores resultados publicados na literatura para matéria-prima lisa, o algoritmo de busca do melhor encaixe apresentou encaixes com eficiências inferiores, porém com resultados superiores ao recomendado pela literatura específica da área de moda para tecidos estampados.
This thesis proposes the solution for the packing problem of patterns on striped fabric in clothing industry. The patterns are pieces with irregular form that should be placed on raw material which is, in this case, the fabric. This fabric is cut after packing. In the specific problem of packing on striped fabric, the position that patterns are put in the fabric should ensure that, after the clothing sewing, the stripes should present continuity. Thus, the theoretical foundation of this project includes subjects about fashion and clothing design, such as types and rapports of striped fabric, and the possibilities of rotation and the correct place to put the patterns on striped fabric. In the theoretical foundation, there are also subjects about research in combinatorial optimization as: characteristics about bi-dimensional packing and cutting problems and algorithms used for several authors to solve the problem. In addition, the Markov Chain Monte Carlo method and the Metropolis-Hastings algorithm are described at end of theoretical foundation. Based on the bibliographic research, two different algorithms for the packing problem with striped fabric are proposed: algorithm with pre-processing step and algorithm of searching the best packing using the Metropolis-Hastings algorithm. Both algorithms are implemented in the Striped Riscare software, which is a continuity of Riscare software for clear fabrics developed in the Masters degree of the author. Both algorithms performances are tested with six literature benchmark problems and a new problem called “male shirt” is proposed here. The benchmark problems of literature were iniatially proposed for clear raw material and the male shirt problem, specifically for striped fabrics. Between the two developed algorithms, the algorithm of searching the best packing has shown better results with better efficiencies of the fabric usage for all the problems tested. When compared to the best results published in the literature for clear raw material, the algorithm of searching the best packing has shown packings with lower efficiencies. However, it showed results higher than recommended for the specific literature of fashion design for patterned fabrics.

Dans le cadre de cette thèse expérimentale, nous étudions le décollement en géométrie de probe tack lors de la transition d'un liquide visqueux vers un solide élastique mou. Notre système modèle (du PDMS à différents degrés de réticulation) assure une transition continue entre ces classes de matériaux. Au début du décollement, une instabilité de digitation avec une longueur d'onde caractéristique apparaît. Pour une huile newtonienne nous expliquons le coarsening des structures par analyse de stabilité linéaire. Pour des propriétés du liquide jusqu'au solide, nous identifions des mécanismes volumiques ou interfaciaux et analysons quantitativement leur longueur d'onde initiale respective. Nous montrons que le mécanisme de décollement est déterminé par la viscoélasticité linéaire et des propriétés de surface. Au cas interfacial, nous expliquons la dépendance en vitesse de l'énergie d'adhésion par des propriétés volumiques et confirmons ainsi une loi empirique. En adaptant une technique 3D récente, nous visualisons in situ la ligne de contact entre le matériau viscoélastique et le substrat rigide, offrant ainsi un accès direct aux conditions aux limites.

Les bulles sont des objets du quotidien qui nous ont amusés étant enfant. Elles sont aussi une source d’inspiration pour les artistes et un outil pédagogique important pour introduire diverses notions de physique. Il n’est pas étonnant que ces objets soient à l’origine de recherches scientifiques depuis des siècles. Dans ce manuscrit, nous nous intéressons à la formation, au transport et à la destruction de bulles interfaciales c’est à dire des bulles en contact avec un solide ou une interface air-liquide. D’abord, nous présentons une expérience sur la formation de bulles interfaciales par impact, à vitesse constante, de films liquides sur la surface d’un bain du même liquide. L’air piégé entre la surface libre du bain et le film liquide conduit à la formation une bulle dont la taille augmente avec la vitesse d’impact. Nous montrons l’existence de deux régimes d’écoulements d’air qui contrôlent la formation de ces bulles : l’un régi par un mécanisme visco-capillaire à basse vitesse d’impact, l’autre, à haute vitesse d’impact, par une compétition entre inertie et capillarité. Nous présentons par la suite une étude sur la vidange d’une bulle interfaciale. Nous revisitons le problème classique de la vidange d’un réservoir en étudiant le cas d’un réservoir déformable, c’est à dire une bulle interfaciale posée sur une plaque percée d’un trou. La vidange est étudiée en fonction des paramètres clefs géométriques et physico-chimiques du problème. Nous montrons que le temps de vidange peut être compris en modélisant l’écoulement d’air qui s’échappe d’une bulle à l’aide du théorème de Bernoulli, et que le déplacement d’une bulle pendant la vidange est piloté par la capillarité et est limité par la friction agissant au pied de la bulle. Nous développons dans le dernier chapitre une méthode éducative pour mesurer la viscosité de l’air avec un matériel expérimental simple de nos vies quotidiennes : un smartphone, un entonnoir, un tube et de l’eau savonneuse. L’expérience consiste à étudier le déplacement spontané d’un film liquide mince dans un entonnoir. Nous montrons que cette expérience peut servir de viscosimètre à air dans des conditions pour lesquelles l’écoulement de l’air peut être décrit par l’équation de Poiseuille et le film liquide se déplace de façon quasi-statique
Bubbles are everyday-life fluid objects that amused us when we were children. Also, they are a source of the inspiration for artists and an important educational tool to introduce several notions of physics. Not surprisingly, these objects are at the origin of many scientific studies for centuries. In this manuscript, we are interested in the formation, travel and destruction of interfacial bubbles, i.e., bubbles in contact with a solid or an air-liquid interface. First, we present an experiment about the formation of interfacial bubbles by the impact, at constant velocity, of liquid films on the free surface of a liquid bath. The air trapped between the bath and the liquid film drives the formation of an interfacial bubble and its size increases with the impact velocity. We show the existence of two distinct regimes of the air flow : one of them is governed by a visco-capillary mechanism at low impact velocity, the other, at high impact velocity, is driven by a competition between inertia and capillarity. Thereafter, we present a study about shrinking surface soap bubbles. We revisit the classical problem of the draining of a tank studying the case of a deformable tank, i.e. , an interfacial bubble sitting on a plate drilled with a circular orifice. Shrinking is studied as functions of key setting geometric and physicochemical parameters of the problem. We show the shrinking time can be understood with a model for the air flow based on Bernoulli’s principle, and a motion of a bubble during the shrinking that is driven by capillarity and is limited by the friction acting on its foot. We develop in the last chapter an educative method to measure the air viscosity with simple experimental equipment regularly used in our everyday life : a smartphone, a funnel, a pipe and soap solution. The experiment consists of studying the spontaneous motion of a thin liquid film in a funnel. We show this experiment can be used as a viscosimeter for gases (air in our experiments) with the conditions make the air flow describable by the Poiseuille’s equation and the liquid film moves quasi-statically

Abstract The effects of dietary sucrose and systemic glucocorticoid treatment on the response of the pulpodentinal complex to dental caries were examined in an experimental rat model. The possible role of dentinal caries on dentin formation was also examined. After 5-6 weeks of a dietary and/or medication period, the areas of dentin formation and dentinal caries were quantified in the molars of growing animals. Also the number and severity of caries lesions were estimated. The 43% sucrose diet significantly reduced dentin formation and increased dentinal caries progression. Although glucocorticoid medication alone reduced dentin formation, without dietary sucrose it did not have an effect on caries. In combination of these two, glucocorticoids further increased the progression of dentinal caries, however without significant increase in the number of caries lesions. The cariogenic bacterial inoculation of rats fed a sucrose or control diet increased the progression of dentinal caries. The relationship between cariogenic bacteria and caries was not strong, but there was a stronger relationship between the total amount of dietary sucrose and dentinal caries. In addition to the overall reduction of dentin formation there was no difference in the amount of dentin formed between intact and carious fissures in the sucrose diet group. On the contrary, rats receiving the control diet positively responded to the dentinal caries by increasing dentin formation to prevent pulpal exposure. Whereas the high sucrose diet impaired both the deposition and mineralization of the dentin matrix, glucocorticoids affected matrix formation only. These results indicate that the functional alterations in the pulpo-dentinal complex might contribute to dentinal caries progression in a cariogenic environment, irrespective of the causative mechanism.

Mollusc shells are unique adaptations that serve to protect the organisms that make them, and are a defining feature of the phylum. However the molecular underpinnings of shell forming processes are still largely unexplored. To further understand mollusc shell formation, I studied three bivalve species in this project: the blue mussel Mytilus edulis, the Pacific oyster Crassostrea gigas, and the king scallop Pecten maximus. While previous analyses of the shell proteomes showed species specificity, transcriptomes of the mantle tissues revealed more commonalities. To reconcile these differences, I studied differential gene expression in shell damage-repair experiments and during the formation of the first larval shell, to produce a comprehensive overview of shell formation processes. Expression data showed large biological variability between individuals, requiring matched-pair experimental designs to detect differential gene expression during shell repair. Loci differentially expressed during shell repair and in the larvae encoded shell matrix proteins, transmembrane transporters, and novel transcripts. A large number of shell matrix proteins, encoded in differentially expressed loci, were common in all three species during shell formation, indicating that shell forming proteins between different species may be more common than previously thought. Differential expression of transmembrane transporters during shell repair indicated that the animals may be regulating bicarbonate ions during shell formation. Finally, the experiments revealed novel transcripts, with unknown annotations to public datasets, that may putatively be involved in shell formation.

In What is Philosophy? (1994) Deleuze and Guattari distinguish between three kinds of thought each in its own way capable of creation: philosophic, scientific, and artistic. The three forms exist as three separate planes. The philosopher creates concepts on the plane of immanence; the scientist lays down functions on the plane of reference or coordination by creating figures or undertaking partial observations; the artist creates affects or sensations on the plane of composition. These three forms of thought are understood as the three active responses of the human brain faced with the chaos of Being; active and necessarily ongoing responses laying down planes on which their concepts, affects, and functions are constantly in movement. These forms are distinguished from 'opinion', a reactive response which pretends that chaos can be tamed once and for all by insisting that concepts, functions, and affects can be forever fixed in place. The three forms not only define themselves against chaos then, they are also in constant conflict with opinion which strives to limit their creation. Throughout What is Philosophy? the purity of the distinction between the three planes is stressed. Indeed Deleuze and Guattari‘s project in this their final book together is to think these very distinctions, to unravel strands of discourse that often appear hopelessly intertwined, to trace the defining creative potential of each discipline. Their chapter on art in particular (’Percept, Affect, and Concept’) seems a remarkable process of alchemy in which the very essence of art is distilled. They demonstrate that art does not represent, it creates affects or sensations (through the transmission of perceptions) which occur in the present existence of the spectator, reader, or listener. The artist invents affects before unknown, and we experience them immanently when we experience the art. These sensations are not representations: we feel, we really feel the affects that have been created. The purity of the distinctions is one of the things which resonates. Deleuze and Guattari conclude that the 'three planes, along with their elements, are irreducible' (1994, 216). Yet in drawing this conclusion they concede that there is of course interference; that the distinctions they have made so clear for us, which have been defined with such elegance, were drawn in fact from a seeming confusion. The chaos is still present. Their book has demonstrated the process of philosophic creation they have described: they have created concepts and set them in motion on the plane of immanence which has been formed over chaos. Yet in the process they have demonstrated that the chaos is not alone in being real, they have indicated an order which also really is.

En fonderie d'aluminium, la présence de microporosités au sein des pièces moulées nuit considérablement à leurs propriétés mécaniques. On comprend par conséquent que la modélisation et la prédiction de la formation des microporosités peuvent être d'un grand soutien pour le fondeur. Dans cette étude, nous avons observé tout d'abord expérimentalement la sensibilité à la formation des microporosités d'alliages binaires d'aluminium-silicium (Al-3%Si, Al-7%Si, Al-11%Si) dans des conditions de solidification unidirectionnelle ou uniforme. La caractérisation de nos essais nous a permis de retrouver certaines tendances déjà observées expérimentalement dans la littérature et notamment une augmentation de la fraction volumique de pores avec: la teneur initiale en hydrogène dissous, une microstructure plus grossière, une pression extérieure plus faible. Au vu de ces résultats, nous avons alors adopté une approche thermodynamique ou nous avons montré notamment que, dans l'intervalle de solidification des alliages d'aluminium, la diminution de la température et l'enrichissement en soluté du liquide résiduel peuvent diminuer considérablement la solubilité de l'hydrogène. Dans ces conditions, la formation des microporosités peut avoir lieu dans les premiers stades de la solidification ou les pertes de pression associées au retrait de solidification sont alors négligeables. Notre étude a abouti à la définition d'un modèle analytique de prédiction de la fraction volumique de pores se caractérisant par les deux étapes suivantes: 1) la détermination de la fraction solide critique à partir de laquelle la formation des microporosités devient thermodynamiquement possible, 2) le calcul de la fraction volumique de pores à partir de la résolution du bilan de masse pour l'hydrogène. Notre approche peut être utilisée pour d'autres alliages d'aluminium et/ou dans des conditions de solidification plus compliquées

Nous analysons l'ecoulement le long de surfaces planes ou axisymetriques pour des polymeres fondus de grandes masses moleculaires, pouvant presenter des interactions varies avec le materiau de paroi. Le glissement du fluide aux parois et la stabilite sont au cur de l'etude. On considerera des surfaces en acier inoxydable, des surfaces de silice, et diverses surfaces fluorees. La rugosite des parois de silice peut etre tres faible, jusqu'a environ 5 angstrom. La composition chimique exacte, et l'etat de surface de chacune de ces filieres ont ete precisees par des analyses physico-chimiques adaptees. Le glissement aux parois a ete analyse et quantifie au moyen d'un banc de birefringence et d'un velocimetre laser. Nous avons trouve une relation entre l'apparition du glissement, l'energie de surface et la rugosite des parois. Selon les conditions experimentales, le glissement peut etre adhesif ou cohesif. En terme de stabilite, le glissement retarde, voire elimine l'apparition des instabilites de surface telles que le defaut de peau de requin. Son impact sur les procedes de fabrication est evident

Les interactions collectives, quoique récurrentes chez les microbes, sont paradoxales du point de vue de la sélection naturelle : les traits individuels qui les sous-tendent sont coûteux, donc sujets à l'exploitation de " tricheurs ". Parmi les modèles théoriques, la plupart privilégient des formalismes statiques et idéalisés, et négligent les processus physiques de formation de groupes. Dans une 1ère partie, je décris un cadre formel général pour modéliser les dynamiques évolutives d'un trait social qui augmente la propension à interagir et la cohésion des groupes. Je prouve que la meilleure agrégation des sociaux (attachement différentiel) leur suffit à s'assortir sans besoin de capacités de reconnaissance mutuelle, allégeant l'hypothèse d'attachement préférentiel fréquemment invoquée dans la littérature en l'absence de sélection de parentèle. Dans une 2nde partie, j'étaye cette preuve de principe en spécifiant un modèle computationnel d'agrégation où les individus exercent les uns sur les autres des forces d'interaction d'intensité dépendant de leur type. Je montre que l'émergence et le maintien de la socialité sont compatibles avec de tels processus de formation de groupes, en détaillant à quelles conditions sur les paramètres écologiques et microscopiques. Ce travail constitue une suggestion de scénario mécaniste pour l'évolution de la socialité au sein de groupes de taille arbitraire, ne requérant ni capacités cognitives pour les individus ni apparentement génétique. Il se veut éclairant sur les déterminants évolutionnistes de la structure sociale d'organismes tels que les dictyostélides et les myxobactéries, ainsi que sur les origines possibles de la multicellularité.

Диссертация на соискание ученой степени кандидата технических наук по специальности 05.17.11 – технология тугоплавких неметаллических материалов. – Национальный технический университет "Харьковский политехнический институт", Харьков, 2015. Диссертация посвящена разработке технологии силикаткальциевых легковесных изделий, полученных прямым твердофазовым синтезом из сырьевых материалов Украины. Исследовано влияние вида и количества известьсодержащих компонентов на фазовый состав и свойства силикаткальциевых легковесных изделий. Установлено, что высокий выход псевдоволластонита (до 92 об. %), полученного путем прямого твердофазного синтеза при одноразовой термообработке непосредственно в изделиях, образуется за счет использования комбинированного известьсодержащего материала, состоящего из мела и гипса полуводного в соотношении 3:1 в пересчете на СаО. Показано, что для изготовления силикаткальциевых легковесных изделий целесообразно использовать кварц молотый пылевидный с преобладающим размером частиц 4–20 мкм. Определена эффективная влажность массы (33 %) для литья легковесных изделий. На основании результа-тов исследования установлены рациональный состав шихты (43 мас. % мела, 20 мас. % гипса полуводного и 37 мас. % кварца пылевидного) и технологические параметры, обеспечивающие получение изделий с кажущейся плотностью 800–1000 кг/м³ и пределом прочности при сжатии 5,0–6,0 МПа с использованием в качестве основного порообразователя воды. Разработана технология силикаткальциевых легковесных изделий с низкими кажущейся плотностью и теплопроводностью, микропористой структурой, высоким содержанием псевдоволластонита, устойчивых к действию расплава алюминия, которая внедрена в ПАО "УкрНИИО имени А. С. Бережного".
The thesis for a candidate’s degree of technical science on the speciality 05.17.11 – technology of hard-melting nonmetallic materials. – National Technical University "Kharkiv Polytechnic Institute", Kharkiv, 2015. The thesis is devoted to the development of calciumsilicate lightweight products technology, obtained by direct solid phase synthesis of raw materials Ukraine. The ration-al composition and technological parameters has been established, which provide calciumsilicate lightweight products with the apparent density 500 – 1000 kg/m³ and compressive strength limit 1,6–6,0 MPa. Is determined that high yield psevdowollastonite (up to 92 vol.%) formed by the use of combined lime contains material, consisting of chalk and gypsum at a ratio of 3: 1 in terms of CaO. Done thermodynamic analysis and the processes of phase formation during heat treatment in the composition of samples, including chalk, gypsum hemihydrate and quartz and pure calcium oxide and silicon with nonstoichiometrically ratio oxides CaO: SiO₂ (0,9) for the formation of wollastonite are investigated. It was established that the formation psevdowollastonite in a mixture of raw materials flows through the formation of intermediate compounds – larnite and β-wollastonite. Is determined that test samples of lightweight products characterized by a microporous structure. The products recommended for application at temperatures up to 1300 and 1250 °C. It is shown that the immutability the phase composition calciumsilicate lightweight products and exclusion of volume changes at polymorphic transformations wollastonite in psevdowollastonite during their service in the thermal aggregates is ensured by directed synthesis psevdowollastonite in products during their heat treatment. It was established that the thermal conductivity of test samples with microporous structure in the ~ 1,2–2,5 times less compared to macroporous chamotte lightweight products. Is de-termined that the developed products resistant to molten aluminum, and it is expedient recommended instead materials containing asbestos. Calciumsilicate lightweight products technology put into production in PJSC "The URIR named after A. S. Berezhnoy".

Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.17.11 – технологія тугоплавких неметалічних матеріалів. – Національний технічний університет "Харківський політехнічний інститут", Харків, 2015. Дисертацію присвячено розробці технології силікаткальцієвих легковагих виробів, що отримані прямим твердофазовим синтезом з сировинних матеріалів України. Встановлено раціональний склад шихти та технологічні параметри, що забезпечують отримання силікаткальцієвих легковагих виробів з уявною щільністю 500–1000 кг/м³ та границею міцності при стисненні 1,6–6,0 МПа. Визначено, що високий вихід псевдоволастоніту (до 92 об. %) утворюється за рахунок використання комбінованого вапновміщуючого матеріалу, що складається з крейди і гіпсу напівводяного у співвідношенні 3: 1 у перерахунку на СаО. Виконано термодинамічний аналіз і досліджено процеси фазоутворення при термообробці у зразках складу, що включає крейду, гіпс напівводяний і кварц пиловидний та з чистих оксидів кальцію і кремнію з нестехіометрічним (0,9) для утворення воластоніту співідношенням СаО : SiO₂. Встановлено, що утворення псевдоволастоніту у суміші сировинних матеріалів протікає через утворення проміжних сполук – ларніту і β-воластоніту. Визначено, що дослідні зразки легковагих виробів характеризуються мікропористою структурою. Отримані вироби рекомендовані для служби при температурах до 1300 і 1250 ⁰С. Показано, що незмінність фазового складу силікаткальцієвих легковагих виробів, а також виключення об'ємних змін при поліморфному перетворенні воластоніту у псевдоволастоніт при їх службі в теплових агрегатах забезпечується за рахунок цілеспрямованого синтезу у виробах псевдоволастоніту при їх термообробці. Встановлено, що теплопровідність дослідних зразків легковагих виробів, які мають мікропористу структуру, у ~ 1,2–2,5 рази має більш низькі значення порівняно з крупнопористими шамотними легковагими виробами. Визначено, що розроблені вироби стійкі до розплаву алюмінію і доцільно рекомендувати їх замість азбествміщуючих матеріалів. Технологію силікаткальцієвих легковагих виробів впроваджено у виробництво у ПАТ "УкрНДІВ ім. А. С. Бережного".
The thesis for a candidate’s degree of technical science on the speciality 05.17.11 – technology of hard-melting nonmetallic materials. – National Technical University "Kharkiv Polytechnic Institute", Kharkiv, 2015. The thesis is devoted to the development of calciumsilicate lightweight products technology, obtained by direct solid phase synthesis of raw materials Ukraine. The ration-al composition and technological parameters has been established, which provide calciumsilicate lightweight products with the apparent density 500 – 1000 kg/m³ and compressive strength limit 1,6–6,0 MPa. Is determined that high yield psevdowollastonite (up to 92 vol.%) formed by the use of combined lime contains material, consisting of chalk and gypsum at a ratio of 3: 1 in terms of CaO. Done thermodynamic analysis and the processes of phase formation during heat treatment in the composition of samples, including chalk, gypsum hemihydrate and quartz and pure calcium oxide and silicon with nonstoichiometrically ratio oxides CaO: SiO₂ (0,9) for the formation of wollastonite are investigated. It was established that the formation psevdowollastonite in a mixture of raw materials flows through the formation of intermediate compounds – larnite and β-wollastonite. Is determined that test samples of lightweight products characterized by a microporous structure. The products recommended for application at temperatures up to 1300 and 1250 °C. It is shown that the immutability the phase composition calciumsilicate lightweight products and exclusion of volume changes at polymorphic transformations wollastonite in psevdowollastonite during their service in the thermal aggregates is ensured by directed synthesis psevdowollastonite in products during their heat treatment. It was established that the thermal conductivity of test samples with microporous structure in the ~ 1,2–2,5 times less compared to macroporous chamotte lightweight products. Is de-termined that the developed products resistant to molten aluminum, and it is expedient recommended instead materials containing asbestos. Calciumsilicate lightweight products technology put into production in PJSC "The URIR named after A. S. Berezhnoy".

Abstract Slope to Basin-floor Evolution of Channels to Lobes, Jurassic Los Molles Formation, Neuquén Basin, Argentina Nataleigh Kristine Vann, MS Geo Sci The University of Texas at Austin, 2013 Supervisor: Ronald J. Steel and Cornel Olariu The relatively steep and short-headed Neuquén Basin margin provides an excellent laboratory for demonstrating down slope changes in sediment gravity flow bed thickness, grain size and facies, as well as channel to lobe transitions. Approximately 400m high clinoformal, shelf-slope-basin-floor deposits of Jurassic Los Molles Formation outcrops are evaluated for reservoir scale definition of facies and architectures in the La Jardinera field area, Neuquén Basin. Slope deposits represent the accretionary front of the prograding shelf margin that were fed by a coarse grained shelf (Lajas Formation). Mapping of a high-resolution satellite images draped on digital elevation model resolved a sub-meter stratigraphic framework. Thirty-three measured sections from outcrops exposed along a 5km transect characterize the evolution of sand body architectures from the shelf edge to the basin floor. The Neuquén Basin margin is typified by four main depositional environments that transition from shelf edge incisions filled with conglomerates, to confined channels in upper- to middle-slope reaches, to weakly confined channels on the lower slope to sheet-like lobes and distributary channel complexes that drape onto both the lower slope and basin floor. Along the slope to basin floor profile the depositional architecture changes by overall decrease in grain size, amalgamation of beds and degree of erosion. Confined slope channels are up to 25m deep, isolated within muddy slope deposits and have complex multistory fills marked by basal and internal erosive contacts lined with mud-clast and/or pebble conglomerates. Channel axes contain amalgamated, medium to coarse sandstones that thin and fine towards channel margins over 100m. Down dip, lower slope channels are up to 400m wide and less than 10m thick. A marked reduction in mud clasts and conglomeratic material at basal erosional surfaces in weakly confined channels represent a downslope decrease in flow energy. However, distinct meter scale erosion surfaces continue to be recognizable where thin ripple laminated sands are truncated on channel margins by amalgamated structureless sands. Erosional surfaces are absent in laterally extensive (>5km), sheet-like lobes of basin-floor fans that are generally finer grained than lower or upper slope channel fills. There are lenticular debrites and thin micro-conglomerates associated with basin-floor fans.
text

This study focuses on the facies changes from the lower slope to toe-of-slope to basin floor over a 10 km outcrop belt, in down-dip and oblique-strike directions to the basin margin. The Jurassic Los Molles Formation in Neuquen Basin, Argentina represents the slope and basin floor of basin margin clinoforms, coeval with the shallow water and fluvial deposits named Las Lajas and Challaco formations respectively. The shallow and deep water deposits are diachronously linked in an Early-Mid Jurassic source-to-sink system developed in a back-arc basin during the incipient development of the Andes Mountains. Satellite images, high resolution panorama pictures and measured sections were used to correlate and interpret the spatial variability and overall geometry of the base of slope to basin floor units. The observations of this study refine the model for the channel-to-lobe transition zone with increase recognition and quantification of facies and architecture variability. The Los Molles basin margin was coarse grained and was ideal to observe changes in the geometry and depositional facies of channel-to-lobe deposits from updip to downdip continuous over an 8 km outcrop belt. The described channel-to-lobe transition zone clearly shows a downdip change in bed boundaries from dominantly erosive to non-erosional (bypass) to depositional and with a range of distinct facies changes. In the transition zone the sand to shale ratio is high (N:G: 65-70 %), with gutter casts and deep scours, with a high degree of amalgamation, gravel lags, mud rip-up clasts and laterally migrating beds. Within the same depositional unit (deep water lobe), at the base of the slope, the dominant sandstone beds change from amalgamated structureless and normal graded sandstone beds in the channelized lobe axis to parallel laminated and normally graded in the channelized lobe off-axis areas. Similar facies changes have been observed along proximal to distal direction. The lateral change of the dominant structures in the beds indicates changes in the flow regime and depositional style.
text

Research Doctorate - Doctor of Philosophy (PhD)
In this work, the relationship between the conditions of carbon deposition from molten carbonate systems and the characteristics of the produced carbons is investigated. Throughout this thesis, both physical and electrochemical analysis techniques have been used to identify variation in the morphological, structural, and electrochemical characteristics of synthesised carbons. The mechanisms and specifics of carbon growth at substrates under certain conditions, with carbon growth at a nucleating metal such as copper being identified and investigated as a special case which gives rise to unique carbon morphologies, and the trends in the variation of physical characteristics of carbons produced through molten carbonate reduction with deposition parameter variation has been explained both in terms of energy of deposition systems and, for the special case of deposition at copper, from a nucleation and growth perspective. The charge-storage characteristics of synthesised carbons has been investigated using cyclic-voltammetry (CV), step potential electrochemical spectroscopy (SPECS), and electrochemical impedance spectroscopy (EIS), and high capacitances associated with high degrees of folding and surface functionalisation have been associated with highly amorphous carbons deposited under low system energy conditions. The presence of inductive behaviour has been identified in the synthesised materials when cycled at an intermediate frequency, and this has been attributed largely to diffusion processes within the microporous structure of the materials. The synthesised carbons have been identified as consisting of a combination of graphitised and amorphous phases with varied topographies. Highly amorphous carbons with high degrees of oxygen functionalisation have been identified as superior for aqueous supercapacitor applications using CV, SPECS, and EIS, and deconvolution of the electric double layer and pseudocapacitive contributions to the total capacitive using SPECS have allowed for links to be drawn between the structure of synthesised carbons and their supercapacitive performance. The parameters of molten carbonate reduction and the cell parameters in three electrode supercapacitors have been optimised to allow for the synthesis of high performing aqueous supercapacitors, with carbons with excellent cycling stability and performances as high as 425 F g^-1 being examined in 0.5 M Na₂SO₄ electrolytes.

Com base na observação do meio natural, é ensaiada a exploração de como utilizar a Natureza enquanto raiz do processo criativo, com o objetivo de identificar formas e elementos característicos já existentes no meio natural e propriedades únicas da matéria. Estas poderão ser utilizadas ou integradas na concepção de objectos, recorrendo à Natureza como agente criativo. Ela sugere, eu aplico. A forma e matéria são recolhidos por deterem determinadas características, e são experimentadas aplicando meios de transformação, maquinação e outras técnicas. Os recursos utilizados são tão elementares quanto possível, tendo em consideração a forma-prima1, de modo a criar algo que transponha e exemplifique a singularidade, delicadeza e personalidade da natureza física em cada peça. A árvore foi o elemento em que o trabalho se centrou. A beleza, as formas e a matéria que proporciona sugeriram três abordagens diferentes: a primeira visa a utilização de ramos em curva ou com bifurcações, tirando partido do valor mecânico proporcionado pela direcção dos veios, permitindo serem componentes de um objecto; a segunda, como complemento à primeira, foca-se na experimentação e produção de aglomerado em caruma; e por fim, a terceira abordagem remete para a experiência e trabalho em vidro soprado, no qual, tanto o vazio de um tronco sem núcleo (cerne), como também, o espaço entre os ramos de uma árvore são utilizados como molde.