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Pastato aprūpinimas šiluma šilumos siurbliu su šiluminiu poliumi / Heat supply to the building using a heat pump with energy pilesŽostautas, Mauricijus 26 July 2012 (has links)
Baigiamajame magistro darbe nagrinėjamas pastato, aprūpinimas šiluma šilumos siurbliu su šiluminiais poliais. Yra apžvelgtos esamos giliosios bei sekliosios geoterminės energijos panaudojimo panaudojimo galimybės Lietuvoje. Aprašytos prielaidos ir supaprastinimai šiluminių polių skaičiavimui, aprašytos skaičiavimo metodikos. Atlikti šiluminių polių skaičiavimai, naudojantis penkiomis metodikomis. Aprašytas pasirinktas pastatas, apskaičiuoti atitvarų šiluminiai rodikliai, nustatyta pastatui reikalinga šiluminė galia. Naudojantis „Design builder“ modeliavimo programa sukurtas pastato modelis ir apskaičiuoti pastato šilumos bei vėsos poreikiai metų laikotarpiu. Pagal nustatytus poreikius modeliavimo programa „EED“ sumodeliuoti šildymo vėsinimo ciklai dvidešimt penkeriems metams į priekį. Sistema palyginta su baziniu šilumos šaltiniu. Išnagrinėjus gautus rezultatus pateikiamos rekomendacijos bei baigiamojo darbo išvados. Darbą sudaro 11 dalių: įvadas, geoterminės energijos panaudojimo galimybės Lietuvoje, šilumos siurblių tipai, šiluminių polių skaičiavimo metodikos bei skaičiavimai, nagrinėjamo pastato aprašymas, pastato šiluminės galios skaičiavimas, pastato šilumos/vėsos poreikių modeliavimas „Design builder“ programa, šiluminių polių skaičiavimas „EED“ programa, nagrinėjamos sistemos palyginimas su baziniu šilumos šaltiniu, rekomendacijos, išvados ir literatūros sąrašas. Darbo apimtis 68 p. teksto be priedų, 49 iliustr., 16 lent., 29 literatūros šaltiniai. / The final master thesis presents analysis of heat supply to the building using a heat pump with energy piles. There is an overview of shallow and deep geothermal energy utilization current possibilities in Lithuania. The assumptions and simplifications of the calculation for the energy piles are described as well as the calculation methodology. Calculations of the energy piles are performed, using five methods. The chosen building is described, thermal performance of partitions are calculated and the building heating capacity is calculated. . Using the "Design Builder" building simulation program a model was generated and the calculations of annual heating and cooling demand are performed. According to the demand of building using simulation program "EED" heating /cooling cycles are calculated of twenty-five years ahead. The system was compared with the basic heat source. After analyzing all results conclusions are given. Thesis consists of 11 parts: introduction, overview of geothermal energy resources usage posibilities in Lithuania, types of heat pumps, calculation methods and calculations of energy piles, description of the building data, calculation of building heating system power, simulation of heat /cooling demand of the building with "Design Builder" program, calculation of energy piles with "EED" modeling program, Comparison of the system with the basic source of heat, recommendations, conclusions and references, Volume of the thesis 68 p. of the text... [to full text]
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Fabrication de piles à combustible par procédés d'impressionBois, Chloe 26 October 2012 (has links) (PDF)
Les piles à combustibles sont une alternative à l'utilisation de ressources fossiles. Cependant, l'énergie qu'elles produisent reste chère et les procédés de fabrication actuels ne sont pas adaptés à des productions à grande échelle. Une piles de type PEMFC (Proton Exchange Membrane Fuel Cell) essont un système constitué de cinq couches dans lequel la membrane et les deux couches de diffusion peuvent être considértestées comme support d'impression et les deux couches actives peuvent être imprimées par des procédés continus.Ce travail démontrea la pertinence du procédé d'impression appelé flexographiquee dans la fabrication de composants de PEMFC. La flexographieCe procédé offre permet de produire de grandes surfaces de production avec peu de perte de matière fonctionnelle. Malgré la faible imprimabilité des supports choisis, elle permit la fabrication des couches actives aux performances similaires à celles fabriquéesites par procédés conventionnels ont pu être réalisées grâce à la flexogaphie.
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Reconnaissance de tâches par commande inverseHak, Sovannara 02 November 2011 (has links) (PDF)
Des méthodes efficaces s'appuyant sur des outils statistiques pour réaliser de la reconnaissance de mouvement ont été développé. Ces méthodes reposent sur l'apprentissage de primitives situé dans des espaces approprié, par exemple l'espace latent de l'espace articulaire et/ou d'espace de tâches adéquat. Les primitives apprises sont souvent séquentielle: un mouvement est segmenté selon l'axe des temps. Dans le cas d'un robot humanoïde, le mouvement peut être décomposé en plusieurs sous-tâches simultanées. Par exemple dans un scénario de serveur, le robot doit placer une assiette sur la table avec une main tout en maintenant son plateau horizontal avec son autre main. La reconnaissance ne peut donc pas se limiter à une seule et unique tâche par segment de temps consécutif. La méthode présenté dans ces travaux utilise la connaissance des tâches que le robot est capable d'accomplir, ainsi que des contrôleurs qui génèreront les mouvements pour réaliser une rétro ingénierie sur un mouvement observé. Cette analyse est destinée à reconnaître des tâches qui ont été exécutées de manière simultanées. La méthode repose sur la fonction de tâche et les projection dans l'espace nul des tâches afin de découpler les contrôleurs. L'approche a été appliquée avec succès sur un vrai robot pour distinguer des mouvements visuellement très proches, mais sémantiquement différents.
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Elaboration et optimisation d'électrodes de piles PEMFC à très faible taux de platine par pulvérisation plasmaMougenot, Mathieu 20 October 2011 (has links) (PDF)
Cette thèse réalisée dans le cadre des projets PIE CNRS AMELI-0Pt et AMEPlas et ANR AMADEUS a regroupé plusieurs entités autour de la thématique des piles à combustible : Dreux Agglomération puis l'Agence Innovation Made In Dreux (MID), le GREMI, le LACCO et initialement l'industriel MHS Equipment. L'objectif de ce travail est l'élaboration par voie plasma et l'optimisation d'électrodes de piles à combustible de type PEMFC et SAMFC dans le but d'obtenir de bonnes performances avec des charges de platine ultra faibles ou sans platine. Le projet a été organisé en quatre étapes : l'étude de la croissance simultanée de platine et de carbone co-pulvérisés par plasma, la dispersion optimale de quantités ultra faibles de catalyseur, le remplacement du platine par un alliage bimétallique à base de palladium, et le dépôt direct du catalyseur sur la membrane par plasma. En utilisant un faisceau synchrotron de rayons X (Synchrotron SOLEIL), en collaboration avec le CRMD, l'étude GISAXS des couches minces Pt-C co-pulvérisés a révélé l'organisation particulière du platine dans ce type de nanostructure. Ces couches minces Pt-C offrent d'excellentes performances (20 kW.gPt-1) avec des charges de platine ultra faibles. Des électrodes PdPt (5 %at Pt) faiblement chargées permettent d'atteindre de bonnes performances en PEMFC quasiment sans platine (12,5 kW.gPd-1 et 250 kW.gPt-1). L'étude de l'activité de catalyseurs PdAu vis-à-vis de l'oxydation du glycérol a révélé l'origine des effets synergiques du palladium et de l'or en milieu alcalin. Le dépôt plasma direct de platine associé ou non au dépôt de carbone sur membrane a été optimisé. Les performances obtenues avec des CCM (Catalyst Coated Membrane) plasma démontrent l'intérêt de ce type d'architecture.
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Static pile-soil-pile interaction in offshore pile groupsChaudhry, Anjum Rashid January 1994 (has links)
This thesis is a theoretical study, using both finite element and boundary element methods, of the behaviour of single-piles and pile groups under vertical and lateral loading. It offers an improved understanding of the soil-structure interaction that occurs in pile groups, particularly closely spaced piles subjected to lateral loads. The potential of a two- dimensional idealisation of what is a three-dimensional problem is demonstrated by achieving real insight into the complex nature of pile-soil and pile-soil-pile interaction in pile groups. A new load transfer mechanism is presented for a rigid, axially loaded vertical pile. From this an improvement is then derived to the analytical solution for pile head settlement given by Randolph and Wroth (1978). The improved mechanism has the further merit that it can be applied also to solutions for flexible piles and pile groups. The improved analytical solution is further adapted in the development of two correcting layers specifically for vertically loaded piles to model infinite boundaries in the finite element model. The correcting layers help in establishing superiority of the finite element method over the boundary element method. To model pile-soil interaction, a purely cohesive interface element is developed and then validated by performing various two-dimensional test problems, including stability analysis of flat surface footings. Footing-soil interface tension is successfully modelled in this way - an outcome that entails a significant modification to the Hansen (1970) bearing capacity solution. Stability analysis is also carried out of conical footings using a three-dimensional finite element model: the results help to explain the applicability of the existing bearing capacity theories to conical footings. The ultimate lateral soil reaction is determined and various pile loading stages are investigated through parametric studies. Study of the stage immediately following pile installation (i.e. the consolidation stage) highlights the need to develop an effective stress analysis for laterally loaded piles. Pile-soil interaction is studied using the cohesive interface element presented earlier, which proves to be quite successful in smoothing out the stress discontinuities around the pile. A new material model for frictional soils is presented, and validated by using it to model an extension test: it captures well post-peak behaviour and takes care of the effects of dilation on the response of laterally loaded piles. Finally, mechanisms of interaction in closely spaced pile groups are studied. Simple analytical expressions are derived which quantify the effects of interaction. A new method of analysis is presented for single-piles and pile groups which offers a considerable degree of reliability without having to do either impossibly expensive full scale field tests or prohibitively expensive full three-dimensional analysis using the currently available computers.
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A model study of the end bearing capacity of piles in layered calcareous soilsEvans, Keith Martin January 1987 (has links)
The results of a series of over 120 model tests to study the end bearing capacity of piles in layered calcareous soils are described. The tests were carried out on samples enclosed in a cylindrical testing chamber, 450 mm diameter and 450 mm high, which allowed independent control of horizontal and vertical stress in the range 25 kPa to 500 kPa. The samples consisted of a loose, uncemented calcareous sand consisting predominantly of foraminifera and mollusc micro-organisms (D50 = 0.2 mm, calcium carbonate content 92%). Into this was built a layer of the same material artificially cemented by a gypsum plaster. The layer had similar properties to naturally cemented deposits, and layers with unconfirmed crushing strengths in the range 500 kPa to 4000 kPa have been prepared. All samples were tested dry. Closed end model piles of 16mm diameter were jacked at 0.1mm/s into the sample, and continuous profiles of end bearing capacity obtained during penetration. A parametric study has been carried out to examine the effects on the bearing capacity of stress level, K0, cemented layer thickness (0.5 pile diameters to 5.0 pile diameters) and layer strength. In addition, tests have been conducted with different pile geometry, multiple cemented layers, and using dynamic installation techniques. The study has identified ranges of parameters for which brittle failure of the cemented layer occurs (low stress levels and high layer strengths) and ranges where the failure is ductile (high stresses and low layer strengths). Characteristic patterns have been observed of the variation of end bearing with position as a layer is penetrated. Examination of the samples after testing has revealed details of failure mechanisms. Simple procedures are proposed for modelling the bearing capacity of such layered systems, and some implications of the results for design methods are discussed.
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The axial capacity of driven piles in clayCoop, Matthew R. January 1987 (has links)
An instrumented model pile was used to investigate the fundamental behaviour in clay soils of driven cylindrical steel piles used for offshore structures. Four test-bed sites were chosen; two in stiff heavily consolidated clays, and two in normally/lightly overconsolidated clays. Data from these sites confirm that a residual shear surface is formed along the pile during installation, the location of which relative to the shaft surface appears to depend on the shaft roughness. Comparisons with other site investigation data and cavity expansion theoretical predictions indicate that stress relief immediately behind the pile tip during driving gives rise to total radial stresses and pore pressures measured on the pile shaft which are lower than predicted. This stress relief is particulary severe in the stiffer clays. The data did however show that the installation total radial stresses and pore pressures are governed by the initial in-situ stresses and undrained shear strength as is predicated by the theory. During reconsolidation, pore pressures close to the instrument rise initially in all clays, and radial effective stresses drop. The slow recovery in radial effective stress during the later stages of reconsolidation was in some cases insufficient to return it to levels recorded during installation. However, the generation of negative pore pressures during undrained loading increased the radial effective stress and shaft friction at failure. This effect is particularly important in the normally consolidated clays, and is responsible for the set-up of shaft capacity seen in such clays, which might not be observed if the loading were drained. The observed behaviour was therefore quite different from the monotonic increase in radial effective stress during reconsolidation, followed by decrease during undrained loading which was expected from a review of current theory.
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Investigation of the end bearing performance of displacement piles in sandXu, Xiangtao January 2007 (has links)
[Truncated abstract] The axial performance of piles in sand remains an area of great uncertainty in geotechnical engineering. Over the years, database studies have shown that the existing method for offshore piles (e.g. API 2000) is unreliable. There is therefore a clear need for an improved predictive method, which incorporates the state-ofthe- art understanding of the underlying controlling mechanisms. This Thesis is dedicated to address the factors influencing the end bearing performance of displacement piles in siliceous sand with a view to proposing and justifying an improved design formulation. Firstly, a database of displacement pile load tests in sand with CPT data was compiled in collaboration with James Schneider (Schneider 2007). It features the widest database with also the latest available pile load test data (e.g. Euripides, Ras Tanajib, Drammen etc) in electronic form. Evaluation of the three new CPTbased methods (Fugro-05, ICP-05 & NGI-05) against this database has revealed a broadly similar predictive performance despite their end bearing formulations being remarkably different. This anomaly promoted the author to extend the database to include additional tests with base capacity measurements to form new base capacity databases for driven and jacked piles, which resulted in the UWA- 05 method for end bearing of displacement piles in sand. This method accounts for the pile effective area ratio, differentiates between driven and jacked piles, and employs a rational qc averaging technique. ... Field tests were performed in Shenton Park, Perth to supplement the database study and, in particular, to examine the effect of the incremental filling ratio (IFR). 10 open-ended and 2 closed-ended piles were tested in compression followed by tension. The test results provide strong support for the UWA-05 method for base capacity evaluation employing the CPT qc values and the effective area ratio. A series of jacked pile tests was carried out on the UWA beam centrifuge, to further explore the factors affecting pile base response. In total, four uniform and four layered centrifuge samples were prepared and tested at various stress levels and relative densities using three separate pile diameters. The resistance ratio (qb0.1/qc,avg) is found to be independent of the absolute pile diameter, effective stress and soil relative density. The tests in layered soil enabled quantification of the reduction in penetration resistance when a pile/cone approaches a weak layer and revealed the significant influence on base stiffness of underlying soft clay layers. The stiffness decay curves (G/GIN vs. w/D, where GIN is initial operational shear stiffness) measured in static load tests were found to vary with ratios of GIN/qc, while there was a unique relationship between G/GIN and qb/qc. A detailed parametric study was carried out (using the FE code PLAXIS) by idealising pile penetration using a spherical cavity expansion analogue in layered soil. The numerical predictions compare well with the centrifuge results and their generalization enabled guidelines to be established for end bearing in layered soil.
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Vers l’éco-conception des piles à combustible : développement d'un procédé de recyclage des catalyseurs des systèmes de PEMFC à base de platine / Fuel cells eco-designDuclos, Lucien 04 October 2016 (has links)
Les piles à combustible (PAC) de type PEMFC permettent d’assurer la conversion d’énergie chimique en énergie électrique en utilisant de l’hydrogène pouvant être produit à partir de sources renouvelables. La catalyse des réactions mises en jeu lors de cette conversion d’énergie nécessite l’utilisation de platine, dont les ressources sont faibles et la production (extraction et raffinage) complexe. De plus, du fait de son prix élevé, ce métal représente une part importante du coût de production des PEMFC. Aujourd’hui, le prix de cette technologie doit être réduit pour qu’elle soit économiquement compétitive et puisse être commercialisée à grande échelle. En outre, les charges en platine dans les électrodes de piles à combustible ne peuvent être réduites significativement sans altération de la performance et de la durabilité de ces systèmes. Donc, le développement d’une filière de recyclage pour assurer la récupération du Pt en fin de vie des PAC pourrait permettre une réduction du coût de production des PEMFC.Cette thèse a consisté à mettre en place une voie de recyclage du platine d’assemblages membrane-électrodes (AME) de PEMFC. Un procédé hydrométallurgique composé des étapes suivantes : (i) lixiviation, (ii) séparation et (iii) récupération du platine a été développé. Différentes alternatives de lixiviation (HCl/H2O2, HCl/HNO3), de séparation (par résine ou solvant), de récupération (sous forme de nanoparticules ou de sel) ont été testées. Le fonctionnement de ces processus de récupération du platine a alors été optimisé à partir de produits modèles (Pt/C et solutions synthétiques). Le choix de ces derniers a ensuite été orienté grâce à une étude d’analyse du cycle de vie (ACV) réalisée à l’échelle de l’AME.Enfin, 76% du platine contenu dans des AME composées de catalyseurs Pt-Co a pu être récupéré. Ce rendement a pu être obtenu après mise en place du procédé composé des étapes suivantes : (i) dissolution du Pt par lixiviation avec le mélange HCl/H2O2, (ii) séparation du cobalt sur résine échangeuse d’ions, (iii) récupération sous forme de nanoparticules par la voie polyol. Les résultats finaux d’ACV ont montré que le recyclage du platine permettrait une nette réduction des impacts environnementaux du cycle de vie d’AME de PEMFC. / The proton exchange membrane fuel cells (PEMFC) can be used to convert chemical energy into electrical energy using hydrogen which can be produced from renewable sources. Platinum (Pt) is the best catalyst used to perform PEMFC electrochemical reaction catalysis. However Pt resources are low and his production (extraction and refining) is complex. Moreover the platinum price represents an important part of the PEMFC stack cost. Nowadays this technology is too expensive to be competitive with conventional energy conversion systems, and cannot be commercialized at a large scale. In addition, PEMFC electrode platinum loading could not be reduced without affecting the system performance and durability. Thus PEMFC production cost could be reduced by recovering platinum from used fuel cells.The main goal of this thesis was to develop a platinum recovery way from fuel cells membrane electrodes-assemblies (MEAs). In order to achieve this objective the following steps were combined in a hydrometallurgical process: (i) leaching, (ii) separation, (iii) recovery. Several alternatives were tested for each step: leaching (HCl/H2O2, HCl/HNO3), separation (resin or solvent), and platinum recovery (as nanoparticles or as a complex). These platinum recovery steps were optimized using Pt/C catalysts and synthetic solutions. Then life-cycle analysis (LCA) methodology has been used to help with the process selection.Finally, about 76% of the platinum contained in multi-metallic catalysts (PtCo/C) MEAs has been recovered. The following path has been followed in this case: (i) dissolution in HCl/H2O2 solution, (ii) separation from cobalt with an ion exchange resin, (iii) recovery has nanoparticles using the polyol process. The LCA study final results showed that a significant reduction of PEMFC MEA life-cycle environmental impact could be achieved by recycling Pt at these systems end-of-life.
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Instalação e capacidade de carga axial de estacas modelo fluidizadas em solos arenosos / Installation and axial load capacity of fluidized model piles in sandy soilsPassini, Larissa de Brum January 2015 (has links)
O objetivo desta tese foi verificar a viabilidade de utilização de jatos de água verticais circulares, únicos e contínuos, provenientes da ponteira de uma estaca torpedo, para auxiliar sua instalação por peso próprio no leito marinho, através da fluidização do solo. Foram realizados ensaios de laboratório, em modelo reduzido, utilizando hastes para simular estacas torpedo (sem aletas) seguindo a lei de semelhança pelo número de Froude. Os ensaios de instalação por peso próprio, com e sem fluidização, ocorreram sem altura de queda, com a estaca modelo em contato com a superfície do leito. Trabalhou-se com três diâmetros de estacas, seis massas, quatros vazões e areia fina saturada compactada em duas densidades relativas iniciais (média e densa). Os ensaios de arrancamento, em leito arenoso fluidizado e não fluidizado, foram realizados imediatamente, 4, 24 e 48 horas após a instalação dos modelos. A metodologia de instalação proposta mostrou-se viável, quando o jateamento é aplicado desde a superfície em solo arenoso. As profundidades instaladas atingidas por fluidização (L/de > 50) foram consideravelmente superiores às profundidades cravadas por apenas peso próprio (L/de < 5). A geometria da zona perturbada durante a instalação por fluidização dos modelos, permaneceu constante e paralela ao fuste, com geometria de aproximadamente 2de em relação ao modelo, independentemente da vazão aplicada e da densidade relativa inicial do solo. A partir das leis de análise dimensional, uma expressão para a profundidade instalada das estacas modelo foi proposta, mostrando que a mesma é função do peso e da geometria do modelo, das propriedades físicas do solo e do fluido, e de sua vazão. Quanto maior a massa do modelo e a vazão aplicada e menor a densidade relativa, maior a profundidade atingida e maior a velocidade inicial de instalação. Constatou-se que a capacidade de carga axial dos modelos depende da densidade relativa, do diâmetro do modelo e do método de instalação (com e sem fluidização). Independentemente da densidade relativa inicial, o solo fluidizado convergiu para a mesma densidade relativa final, próxima as suas condições no estado crítico. As estacas em solo fluidizado apresentaram ganho resistência com o tempo (efeito de setup), com capacidade de carga inferior às estacas cravadas em solo não fluidizado. / The aim of this thesis was to investigate the feasibility of using circular vertical water jets, single and continuous, from the tip of a torpedo pile, to assist its installation by own weight on the seabed, through soil fluidization. Laboratory model tests were carried out, using tubes to simulate torpedo piles (without wings) following the law of similarity defined by the Froude number. The installation tests by the pile own weight, with and without fluidization, occurred without drop height, with the piles in contact with the surface of the bed. Three diameters of model piles and six masses, four flow rates and saturated sand at two initial relative densities (medium and dense) have been used in this set of experiments. Pullout tests in fluidized and nonfluidized soils were performed immediately, 4, 24 and 48 hours after the installation of the models. The proposed installation methodology proved to be feasible when the fluidization is applied from the surface in sandy soils. The installation depths achieved by fluidization (L/de > 50) were significantly higher than the depths reached by pile own weight (L/de < 5). The geometry of the perturbed zone during model installation by fluidization remained constant and parallel to the shaft in a geometry of about 2de of the pile model, regardless of the applied flow rate and the initial relative density of the soil. Following the laws of dimensional analysis, an expression for the embedment of fluidized piles is derived, showing that the penetration depth is a function of pile weight and geometry, fluidized water jet flow rate and velocity, as well as the soil and fluid properties. Increasing the model mass and fluidized flow rate and decreasing the relative density leads to an increase in the depth reached and the initial speed of installation. The axial load capacity of the models depends on the soil relative density, piles diameter and installation method (with and without fluidization). Regardless the initial relative density, the fluidized soil converged to the same final relative density, near its conditions of critical state. Piles installed in fluidized soil presented gain of axial capacity over time (setup effect) with lower resistance than piles driven in nonfluidized soil.
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