Cette thèse a pour objet l'architecture de passage qui ponctuait le parcours d'un visiteur ou d'un citoyen au sein du paysage urbain micrasiatique : propylées, portes urbaines et arcs sur rue. Notre travail portait sur les cités d'Asie Mineure, sans cadre géographique restrictif, afin d'obtenir une vision globale du phénomène étudié. L'étude a été partagée en deux grands ensembles : les propylées d'un côté et les portes urbaines et arcs sur rue d'un autre. Les propylées constituaient les entrées monumentales de sanctuaires, agoras, gymnases et bouleutérions. Notre étude comprend les propylées depuis l'époque classique jusqu'à l'époque romaine. Les propylées classiques constituaient essentiellement les entrées monumentales des grands sanctuaires-terrasses hécatomnides de Carie. A l'époque hellénistique, les propylées se sont multipliés et se trouvaient désormais en contextes cultuels et profanes. Les propylées romains représentaient pour la plupart des entrées monumentales rajoutées à des complexes préexistants, peu appartenaient à un nouveau complexe. Nous trouvons des propylées qui reprenaient des formules de l'époque hellénistique, des propylées à façade monumentale édiculée, des propylées qui adoptaient la forme de l'arc romain et enfin des propylées qui reprenaient la forme des salles impériales. Les portes urbaines totalement dépourvues de tout caractère défensif se sont développées grâce au climat de sécurité de la Pax Romana. Elles marquaient la séparation entre l'intérieur et l'extérieur de la ville, constituaient un véritable repère topographique et, comme la première image que le visiteur avait de la ville, elles annonçaient la splendeur de la ville et projetaient la valeur de l'urbanistas. Ces portes urbaines étaient soit de nouvelles portes insérées dans les anciens remparts, soit libres de tout rempart, soit un réaménagement des anciennes portes. Les arcs sur rue étaient construits sur une rue à colonnades ou à un carrefour pour des raisons urbanistiques et organiques et esthétiques. Tout en embellissant un parcours, ils ponctuaient et articulaient celui-ci et servaient aussi de points de repère. Leurs façades, richement décorées, participaient à l'embellissement et à l'animation des paysages urbains. Ces arcs apparaissaient comme une composante d'un programme urbanistique. Certains arcs étaient honorifiques ou commémoratifs. A l'époque romaine, l'architecture de passage reflétait les changements de la vie politique et de la structure sociale. L'autoreprésentation, la propagande impériale et la vive concurrence entre les cités vont jouer un rôle important dans la conception de ces monuments. Leur richesse et leur magnificence devaient impressionner les visiteurs et donc augmenter l'image reflétée par la cité de sa puissance et de sa gloire.Ils participaient donc à l'ornementation de la cité. / This thesis deals with the architecture of passage that punctuate the course of a visitor or a citizen in the urban landscape of Asia Minor : propylaea, city-gates and arches on street. Our work focused on the cities of Asia Minor with no geographical limits in order to provide an overall view of the phenomenon. This study was divided into two major groups : the propylaea on the one hand and city-gates and arches on street on the other hand. The propylaea were the monumental entrances to shrines, agorai, gymnasiums and bouleuteria. Our study includes the propylaea from the classical period to the Roman era. Classical propylaea were mainly the monumental entrances to the major hecatomnid's shrines-terraces of Caria. In the Hellenistic period, the propylaea multiplied and tuned into religious and secular backgrounds. Most Roman propylaea made up monumental entrances added to existing complexes, few being part of a new one. We find some propylaea that went back over formulas of the Hellenistic period, others with monumental edicular façade, those in the form of the a Roman arch and finally the propylaea reproducing the form of "Marmorsaal". City-gates, that were completely devoid of any defensive features, developed in the peaceful period of the Pax Romana. They marked the boundary between the inside and the outside of the city, were a real topographical landmark and, as the first glimpse of the city for the visitors, heralded its splendor and highlighted the value of the urbanitas. These city-gates were either new city-gates inserted into the ancient city-walls, free of any city-walls, or old city-gates rearranged. The street arches were built on a colonnaded street or at a crossroads for urban, organic and aesthetic reasons. While beautifying a course, they structured and punctuated it as well as serving as landmarks. Their richly decorated facades participated in the beautification and animation of the urban landscape. These arches appear as a component of an urban program. Some of them were honorific or commemorative. In Roman times, the architecture of passage reflected changes in the political life and social structure. The self-representation, the imperial propaganda and the fierce competition between cities would play a major part in the designing of these monuments. Their richness and splendor must have impressed visitors and thus enhanced the city's power and glory picture. They participated in its ornamentation.

A CO2 emission analysis and system investigation of a direct fuel cell waste energy recovery and power generation system (DFC-ERG) for pressure letdown stations was undertaken. The hybrid system developed by FuelCell Energy Inc. is an integrated turboexpander and a direct internal reforming molten carbonate fuel cell system in a combined circle. At pressure letdown stations, popularly called city gates, the pressure of natural gas transported on long pipelines is reduced by traditional pressure regulating systems. Energy is lost as a result of pressure reduction. Pressure reduction also results in severe cooling of the gas due to the Joule Thompson effect, thus, requiring preheating of the natural gas using traditional gas fired-burners. The thermal energy generated results in the emission of green house gases. The DFC-ERG system is a novel waste energy recovery and green house gas mitigation system that can replace traditional pressure regulating systems on city gates. A DFC-ERG system has been simulated using UniSim Design process simulation software. A case study using data from Utilities Kingston’s city gate at Glenburnie was analysed. The waste energy recovery system was modelled using the design specifications of the FuelCell Energy Inc’s DFC 300 system and turboexpander design characteristics of Cryostar TG120. The Fuel Cell system sizing was based on the required thermal output, electrical power output, available configuration and cost. The predicted performance of the fuel cell system was simulated at a current density of 140mA/cm2, steam to carbon ratio of 3, fuel utilization of 75% and oxygen utilization of 30%. The power output of the turboexpander was found to strongly depend on the high pressure natural gas flowrate, temperature and pressure. The simulated DFC-ERG system was found to reduce CO2 emissions when the electrical power generated by the DFC-ERG system replaced electrical power generated by a coal fired plant. / Thesis (Master, Chemical Engineering) -- Queen's University, 2010-08-31 02:02:11.392