The objectives of this study are to measure the non-methane volatile organic carbon (NMVOC&#039 / s) emissions from passenger cars in Turkey having gasoline engines, to determine emission factors of these vehicles for BTEX compounds and comparison of emission factors obtained in this study with the emission factors of the other countries. This study was conducted in two parts: The first part was to determine the categories of passenger cars widely used in Turkey, and also to determine the average carbon monoxide (CO) and hydrocarbon (HC) emissions at idle condition for these car types based on the exhaust emission measurements of Ankara &Ccedil / evre Koruma Vakfi (AN&Ccedil / EVA). The second part of the study was to analyze the gas composition of exhaust gasses at different road conditions for BTEX components by using gas chromatography. The results of the study have shown that the cars named under &lsquo / &lsquo / Tofas&rsquo / &rsquo / constitute 31.5% and &lsquo / &lsquo / Fiat&rsquo / &rsquo / 13.1% of the total cars in Turkey and they are manufactured by the same company. Therefore, studies have been performed with &lsquo / &lsquo / Tofas/Fiat&rsquo / &rsquo / cars. The highest emission factors among hydrocarbons investigated in this study were found for toluene and m-xylene. Generally, as driving speed increases the emissions of HC&rsquo / s are found to decrease in concentration. It was interesting to note that the highest emissions occur at 30 km/hr speed which is the mostly used speed in crowded streets and busy intersections. Therefore, it was concluded that it is very important to take measures for emissions in the city traffic. Cold start emissions were also found to be higher than the hot start emissions.

In this study, combustion performances and emission characteristics of olive cake and olive cake+coal mixture are investigated in a bubbling fluidized bed of 102 mm inside diameter and 900 mm height. The average particle sizes of coal and olive cake used in the experiments were 1.57 mm and 1.52 mm, respectively. Flue gas concentrations of O2, CO, SO2, NOx, and total hydrocarbons (CmHn) were measured during combustion experiments. Operational parameters (excess air ratio, secondary air injection) were changed and variation of pollutant concentrations and combustion efficiency with these operational parameters were studied. The temperature profiles measured along the combustor column was found higher in the freeboard for olive cake than coal due to combustion of hydrocarbons mostly in the freeboard. The location of the maximum temperature in the freeboard shifted to the upper part of the column, as the volatile matter content in the fuel mixture increased. Combustion efficiencies in the range of 83.6-90.1% were obtained for olive cake with the excess air ratio of 1.12-2.30. The corresponding combustion efficiency for coal was 98.4-99.7% under the same conditions. As the CO and hydrocarbon concentration in the flue gas increased, the combustion efficiency decreased. Also co-combustion experiments of olive cake and coal for various mixing ratios were carried out. As the amount of olive cake in the fuel mixture increased, SO2 emissions decreased because of the very low sulfur content of olive cake. In order to increase the combustion efficiency, secondary air was injected into the freeboard which was a good solution to decrease the CO and hydrocarbon emissions, and to increase the combustion efficiency. For the setup used in this study, the optimum operating conditions with respect to NOx and SO2 emissions were found as 1.35 for excess air ratio, and 30 L/min for secondary air flowrate for the combustion of 75 wt% olive cake and 25 wt% coal mixture. Highest combustion efficiency of 99.8% was obtained with an excess air ratio of 1.7, secondary air flow rate of 40 L/min for the combustion of 25 wt% olive cake and 75 wt% coal mixture.

Carbon dioxide is one of the greenhouse gases which have strong impacts on the environment and its amount in the atmosphere is far beyond to be ignored. Carbon dioxide levels are projected to be reduced by sequestering it directly to the underground. High amounts of carbon dioxide can be safely stored in underground media for very long time periods. Storage in depleted gas reservoirs provides an option for sequestering carbon dioxide. In 2002, production of Kuzey Marmara gas reservoir has been stopped due to gas storage plans. Carbon dioxide sequestration in Kuzey Marmara field has been considered in this study as an alternative to the gas storage projects. Reservoir porosity and permeability maps were prepared with the help of Surfer software demo version. These maps were merged with the available Kuzey Marmara production information to create an input file for CMG-GEM simulator and a three dimensional model of the reservoir was created. History match of the field model was made according to the 1998-2002 production data to verify the similarity between the model and actual reservoir. Kuzey Marmara field is regarded as a candidate for future gas storage projects. The reservoir still contains producible natural gas. Four different scenarios were prepared by considering this fact with variations in the regional field properties and implemented into previously built simulation model. These scenarios primarily focus on sequestering carbon dioxide while producing as much as natural gas possible. After analyzing the results from the scenarios it is realized that / CO2 injection can be applied to increase natural gas recovery of Kuzey Marmara field but sequestering high rate CO2 emissions is found out to be inappropriate.

La thèse de doctorat est consacrée aux aspects afférents à l’art dans l’œuvre de Marcus Terentius Varro, encyclopédiste romain du premier siècle avant notre ère. Son œuvre, en partie conservée, en partie réduite à l’état de fragments, a été transmise notamment par Pline l’Ancien, Aulu-Gelle et différents grammairiens romains. En guise de propédeutique, un développement sur un ouvrage de Varron, les 'Disciplinarum Libri', est proposé, situant les arts libéraux dans un cadre philosophique, suivi de la genèse de la critique d’art varronienne, remontant à Platon et Aristote ainsi qu’à Xénocrate d’Athènes. En parallèle, les conceptions artistiques de Cicéron, contemporain de Varron, sont présentées. S’ensuit une partie consacrée à l’architecture qui s’intéresse aux demeures des hommes, puis aux demeures des dieux. Un excursus se focalise sur la 'uilla' de Varron à Casinum ainsi que sur son tombeau. Dans la partie suivante sont présentés les regards du Réatin sur les sculpteurs grecs et hellénistiques, puis sur ceux de son temps, chacun faisant l’objet d’un développement particulier. La même approche est ensuite employée au sujet de la peinture, proposant des notices individuelles sur les peintres grecs et romains et offrant des prolongements par le biais de l’étude d’une Satire Ménippée particulièrement liée au sujet de la thèse ainsi que par l’analyse de l’œuvre qui a offert à Varron un terrain privilégié pour exprimer ses jugements de critique d’art : le 'De imaginibus'. Une ample synthèse conclusive expose les influences exercées par les opinions et les écrits d’un Varron aux goûts esthétiques marqués d’éclectisme, appréciant des œuvres du passé et du présent, figurant des dieux et des hommes, des paysages et des objets, avec toutefois une préférence marquée pour le classicisme et la tradition. Enfin, un développement final envisage la question de l’influence des écrits varroniens relatifs aux arts sur le classicisme augustéen ainsi que sur la politique de restauration conduite par le vainqueur d’Actium. / This thesis is devoted to aspects related to art in the work of Marcus Terentius Varro, a Roman encyclopedist from the first century BCE. His work, partly preserved, partly reduced to fragments, was passed on namely by Pliny the Elder, Aulus Gellius, and various Roman grammarians. The first part will emphasize on one of Varro’s works, the 'Disciplinarum Libri', in order to situate liberal arts in a philosophical framework, and on the genesis of varronian art criticism, dating back to Plato and Aristotle as well as Xenocrates of Athens. In parallel the artistic concepts of Cicero, contemporary with Varro, are presented. This section is followed by one dedicated to architecture, relating to men’s dwellings, and the homes of the gods. An excursus focuses on the villa of Varro in Casinum and on his tomb. In the next section, the views of the Reatinian on Greek and Hellenistic sculptors as well as the ones of his era are presented, each being subject of a particular development. The same approach is then applied on painting, offering individual notes on the Greek and Roman painters. Extensions are brought through the study of a Menippean Satire which is particularly related to the topic of the thesis, and by the analysis of 'De imaginibus', the work which gave Varro a fertile ground for expressing judgments of art criticism. A thorough conclusive synthesis exposes the influences exerted by the opinions and writings of Varro, whose aesthetic tastes can be described as eclectic. He enjoyed the works of past and present, depicting gods and men, landscapes and objects, but kept a marked preference for classicism and tradition. A final development considers the question of the influence of art-related varronian writings on Augustan classicism, and considers the restoration policy led by the victor of Actium.