Le travail de cette thèse constitue une contribution à l'étude des capteurs solaires thermiques. Ainsi, nous cherchons à comprendre les mécanismes d'écoulement et de transfert en convection naturelle interne, en géométrie tridimensionnelle dans la lame d'air d'un capteur solaire dans le but de trouver la conception optimale qui permet un contrôle thermique adéquat et une performance énergétique.Une partie de cette thèse est donc consacrée à une simulation numérique basée sur la mise au point d'un modèle de la convection naturelle dans la lame d'air de forme parallélépipédique fermée contenant de l'air et inclinée d'un angle α. Les simulations ont été faites afin de déterminer les champs de température et de vitesse sous l'influence de la variation de l'épaisseur de la lame d'air, le flux de chaleur apporté à l'absorbeur et la présence d'obstacles dans la lame d'air. Ces simulations ont été effectuées avec et sans rayonnement dans la lame d'air. Le logiciel de calcul utilisé pour cette étude est le CFD fluent, basé sur la méthode des volumes finis Les résultats obtenus montrent l'influence de l'épaisseur de lame d'air sur le régime d'écoulement ; ce dernier peut être stationnaire stable ou instationnaire. Les valeurs du coefficient du transfert thermique ont été calculées pour tous les cas étudiés et une comparaison de l'écoulement avec et sans rayonnement a été faite. / This thesis aims to study the solar thermal collectors. Thus, we seek to understand the mechanisms of natural convective heat transfer in the air gap of a solar collector, in order to find an optimal design which allows adequate thermal control and energy performance.Part of this thesis is devoted to the numerical simulation using fluent, based on the development of natural convection model in an inclined parallelepiped air gap of solar collector. Fluent CFD software is based on the finite volume method. The simulations were carried out to determine the velocity and temperature fields under the effect of the air gap thicknesses, the heat flux provided to the absorber and the presence of obstacles in the air gap. The results show the effect of the air gap thickness on the flow regime, which can be steady or unsteady. These simulations were performed with and without the coupling of convection-radiation in the air gap. Values of the coefficient of heat transfer was calculated for different cases and a comparison for both cases with and without taking into account radiation was made. The numerical study was followed by an experimental work based on the study of solar collector. To reduce heat losses, experiments were carried out to evaluate the thermal behavior of solar collector under external conditions (sunshine, temperature...etc) and the coolant flow rate for various gap air thicknesses. The results show the effect of the air gap thickness on the thermal performance and the importance of having an optimum thickness for better performance. Similarly, the introduction of barriers also contributes to improve the performance of the solar collector.

Cette thèse a pour principal objectif d'analyser l'existence des groupes de collectionneurs d'art contemporain en France au niveau régional (l'exemple de la région Languedoc-Roussillon sera approfondi) et au niveau national de 1980 à nos jours. Il s'agira de cerner les contours et l'organisation de ce groupe social, d'en comprendre les caractéristiques communes ainsi que la sociabilité qui lui est propre et les interactions entre ses membres. La compréhension des modes de différenciation et d'éventuelle hiérarchisation du groupe des collectionneurs d'art contemporain peut nous aider à comprendre les mécanismes qui sous-tendent les décisions et, notamment la dimension d'impulsion dans l'achat d'œuvres d'art. Certains des collectionneurs devenant des leaders dans leur groupe social, leur poids économique, mais aussi social, et leur implication sur le marché de l'art à différents niveaux leur offrent la possibilité d'influer sur la cote des artistes d'art contemporain, ce qui sera analysé dans ce travail de thèse. le marché de l'art contemporain est un marché financier et spéculatif. Il s'apparente, par de nombreux aspects, aux marchés économiques classiques et peut faire l'objet de placements dont il conviendra de faire ressortir les logiques. Par ailleurs certaines caractéristiques semblent indiquer qu'une part de similitude existerait entre le groupe social des collectionneurs et celui de la grande bourgeoisie. Ce travail doit nous permettre de mieux comprendre les interactions entre ces deux groupes. La méthodologie employée pour ce travail sollicitera un certain nombre d'outils propres aux sciences sociales et humaines : l'entretien compréhensif, l'enquête quantitative, l'étude documentaire et l'enquête de notoriété, l'immersion et l'observation participante. / The purpose of this thesis is to analyse contemporary art collectors in France from 1980 to the present, and the way they have come together, sketching this social group’s outline and organization in order to figure out its common characteristics as well as its particular sociability and the interactions among its members. Studying the integration and differentiation dynamics, as well as a potential hierarchy within this group of contemporary art collectors, may help understand certain mechanisms upon which the members’ decisions are based, in particular the concept of buying artwork on impulse. This research was done by building a social visibility index for collectors, by studying their role in contemporary art associations, and by conducting thirty-nine comprehensive interviews with private collectors. In this way, we were able to shed light on a true social group and its multifaceted involvement in the art world. We were likewise able to understand the use of contemporary art as a tool for social differentiation or even as a way for an intellectual and economic elite to distinguish itself from the rest of the population, thereby protecting itself from the cultural democratization and maintaining sufficient distance from new economic elites who use contemporary art more selectively as a tool for social and financial status.

One of the traditional approaches to reduce costs of solar energy is to use inexpensive reflectors to focus the light onto highly efficient solar cells. Several research projects have resulted in designs, where the excess heat is used as solar thermal energy. Unlike a solar thermal system, which has a selective surface to reduce the radiant heat loss, a CPV/T (Concentrating PhotoVoltaic/Thermal) system uses a receiver covered with solar cells with high thermal emittance. This project analyzes whether the heat loss from the receiver can be reduced by covering parts of the receiver surface, not already covered with solar cells, with an optically selective coating. Comparing different methods of applying such a coating and the long-term stability of low cost alternatives are also part of the objectives of this project. To calculate the heat loss reductions of the optically selective surface coating a mathematical model was developed, which takes the thermal emittances and the solar absorptances of the different surfaces into account. Furthermore, a full-size experiment was constructed to verify the theoretical predictions. The coating results in a heat loss reduction of approximately 20 % in such a CPV/T system and one of the companies involved in the study is already changing their design to make use of the results.

Im Rahmen der vorliegenden Arbeit wurden Fertigungstechnologien zur kostengünstigen Herstellung eines neuartigen solarthermischen Kollektors entwickelt. Dieser Kollektor soll aus einem profilierten Grundkörper aus Schaumglas bestehen, welcher mit Flachglas abgedeckt ist. Die Herstellung des Schaumkörpers wurde betrachtet von der Auswahl der Rohstoffe, über die Entwicklung geeigneter Verfahrensparameter, bis zur Formgebung. Ein Schaumkörper mit profilierter Oberfläche konnte im Maßstab von 600 x 600 x 130 mm³ hergestellt werden. Zur Kosteneinsparung wurde hierfür ein Reststoff aus der Glas verarbeitenden Industrie verwendet. Um den Kollektor in ein hydraulisches System eingliedern zu können, wurde eine Technologie zur Einbindung von Rohrleitungsanschlüssen entwickelt. Emaillierte Rohrbögen aus Gusseisen konnten im Schäumungsprozess fest in den Schaumkörper integriert werden. Weiterhin wurden zwei Möglichkeiten zur Anbindung der Deckgläser untersucht. Dabei wurden mittels Klebung durch EVA-Folie eine höhere Verbundfestigkeit erreicht als mittels Löten durch Aluminium-Blech.

This project investigates the optimisation of platinum-group metals recovery at the Mimosa Mine in Zimbabwe. The first part of this research investigates how collector performance can be improved by using collector combinations (mixtures) of the standard sodium iso-butyl xanthate with a secondary collector. The synergistic effect of the sodium-iso-butyl-xanthate (SIBX) combined with trithiocarbonates (TTCs) or dithiophosphates (DTP) was investigated. The short chain and the long chain TTCs were investigated. These collector combinations were studied at various molar percent ratios. The SIBX:DTP combination was studied at a 1:1 mass ratio or molar ratio of 1:1.3. Amongst all the collector combinations, it was established that the SIBX/DTP combination improved sulphur recoveries by 10% and subsequently the PGE+Au recovery by 10% compared to when the SIBX was used on its own. The C4-TTC showed poor performance in the sulphur recovery; however an improvement in PGE + Au recovery was noticeable. There was generally no significant metallurgical improvement with respect to final grades and recoveries with C10 and C12TTC mixtures with SIBX. However, the 6.25 molar per cent substitution of SIBX by C12TTC appeared to show some improvement on sulphur but not on PGM+Au recovery and grade. It was therefore concluded that the SIBX/DTP combination at 1:1 mass ratio (total moles of 0.64) showed a potential to improve the grades and recoveries of the Mimosa Mine. The Mimosa ore is characterised by an unusually large amount of talc, which often causes problems during the flotation of the PGM minerals due to the fact that talc consumes high amount of reagents. Therefore the purpose of the second part of this thesis was to investigate the possibility of removing talc prior to the flotation process by de-sliming. Two cyclones (36.9 mm and 76.0 mm) were used for de-sliming the flotation feed. De-sliming the ore was able to reduce the depressant dosage up to 300 g/t as opposed to 500 g/t that is used at Mimosa Mine. / Dissertation (MSc)--University of Pretoria, 2008. / Materials Science and Metallurgical Engineering / unrestricted

Considéré comme une étude préparatoire subordonnée à l’œuvre finale, le dessin a longtemps été un objet de collection réservé aux artistes et à quelques connaisseurs. À partir de la seconde moitié du XVIIIe siècle, ce regard porté sur le dessin évolue indéniablement. En prenant appui sur diverses sources (inventaires après décès, catalogues de ventes, presse périodique, correspondances, livrets et critiques d’expositions…), cette étude tente de déterminer quels facteurs contribuent à l’émergence de ce goût et de quelles manières il se manifeste au sein de divers Salons, sur le marché de l’art ainsi que dans les cabinets privés. La croissance du nombre de collectionneurs de dessins à partir de la seconde moitié du XVIIIe siècle constitue l’une des principales manifestations de la diffusion de ce goût. Nous avons ainsi cherché à déterminer qui sont ces « nouveaux » collectionneurs, quelle place est accordée au dessin au sein de leurs cabinets et quelles sont les grandes tendances de leurs goûts. Ces nombreuses collections qui apparaissent au cours du XVIIIe siècle réunissent plusieurs dizaines, centaines, voire milliers de feuilles. Nous avons ainsi étudié les méthodes de classement, de conservation et de présentation des dessins. Aborder cette question des pratiques quotidiennes implique de s’intéresser aussi aux nouvelles formes de sociabilité qui se développent autour de ce dernier. À l’instar du cabinet de tableaux, la collection de dessins devient au cours du XVIIIe siècle un espace de rencontre, d’échange et de formation. De plus, le XVIIIe est aussi marqué par l’essor du dessin en amateur, comme en témoignent les nombreuses feuilles conservées aujourd’hui dans les plus grands musées. / Considered as a preliminary work to painting, the drawing has for a long time been considered as a collection’s item only reserved to artists and a few connoisseurs. However, from the second half of the 18th century, this look at the drawing undeniably changed. On the basis of various sources (inventories after death, sales catalogs, correspondences, press, booklets and critics of exhibitions …), this study mainly aims at understanding which factors contributed to the emergence of this taste, and how this became perceptible in Salons, in the art market and in private collections. The growing number of drawing collectors in the second half of the 18th century, is one of the most significant expression of this emergence of a taste for drawings. We tried to determine who were these “new” collectors, which place was given to drawing in their cabinets and what were the main trends of the collectors’ tastes. These numerous collections which appeared during the second half of the 18th century included several tens, hundreds or even thousands of sheets. We thus studied the methods of classification, presentation and conservation of drawings. However, studying this issue of collectors’ daily practices involved to additionally study the new forms of sociability which developed around the drawings. Like the cabinet of paintings, the collection of drawings became a place of meeting, exchanging and educating ones’ self. Moreover, the 18th century was particularly marked by the rise of the amateur drawing, as evidenced by the large number of sheets which are conserved in the greatest museums.

La basura y los desechos son problemas presentes desde un inicio en las ciudades y proponen verdaderos problemas urbanos, sanitarios y sociales para estas. La ciudad de Lima entre sus diversas dinámicas económicas urbanas posee lugares donde el reusó de basura se constituye como una actividad económica central. Uno de estos es el barrio de Manzanilla, donde si bien tradicionalmente se promueve una actividad beneficiosa para la ciudad como lo es la economía circular (específicamente el reusó), esta de desarrolla en desorden tugurización e inseguridad. El proyecto se inserta como parte del actual plan de regeneración urbana que la municipalidad de Lima prevé para esta zona de la ciudad y así servir como equipamiento urbano especializado en la venta de productos reusables. Al mismo tiempo, el proyecto usa el mismo concepto del reúso, el reúso de estructura industriales antiguas presentes en el terreno y les da una nueva función como estructuras virtuales, referenciales y museográficas. / Garbage and waste are problems present from the beginning in the cities and propose real urban, health and social problems for them. Lima among its diverse urban economic dynamics has neighborhoods where reuse is constituted as a central economic activity. One of these is the neighborhood of Manzanilla, where although traditionally promotes a beneficial activity for the city as it is the reused it develops in disorder, slum and insecurity. The project is inserted as part of the urban regeneration plan that the Municipality of Lima envisages for this area of the city and thus serve as urban equipment specialized in the sale of reusable products. At the same time the project uses the same concept of reuse, the reuse of old structures present in the field and gives them a new function as virtual, referential and museographic structures. / Tesis

The first part of diploma thesis describes how to measure the parameters of solar thermal collector and solar thermal system. The computational part analyzes heat consumption in the evaluated building and describes design of the solar thermal system for domestic hot water. Last part focuses on the energy assessment of the designed solar system above and evaluation of the solar system, which is located at the Faculty of Civil Engineering in BUT.

The presented MSc. thesis is focused on the introduction and application of PDMS software in the process piping designing area. The introduction to the employing of the PDMS software is elaborated in the first part of the thesis as practical user manual of this software followed by the benefits of this software as a recognized supportive design program are consequently illustrated on partial solved cases from common design practice. The particular benefit of deploying PDMS in design practice is demonstrated in the thesis by economic evaluation of two selected solved industrial projection cases where design optimization of process piping system is solved with the support of this software system. Introduction of new ones broadening possibilities and current trends in the supportive design software systems, specifically using the scanner and supporting Everything3D are also presented as part of the thesis on a concrete example of the reconstruction of the boiler room.

In the first part of my thesis, I was studying materials about using solar energy. Then I write search about all components that are necessary to be used in solar systems. After that I designed the structure of solar system used for heating the hot water for a family house about 4 persons. For this system I designed a regulator and one layer circuit board using Eagle layout editor 4.12r2, which I assembled and tested. This followed creating and debugging program for microprocessor that controls the whole device. This functional regulator for solar collectors connected in a box together with the necessary electronic components is my final product of this project.