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Öğe Characteristics and biogas potential of extended aeration activated sewage sludge(WFL Publisher Ltd., 2014) Çoban, V.; Çagman, S.; Eyidogan, M.; Kaya, D.As a result of the gradual decrease in the rural population and developments in urbanisation within the last century, the emerging problem of domestic wastewater was tried to be solved with wastewater treatment plants. Haphazardly release of wastewater from households into the nature causes water contamination at rivers, lakes and underground waters because it contains heavy metals. Water contamination is caused by the collapsible, dissolved or suspended chemical and biological substances within wastewater. These chemical and biological substances in wastewater while decomposing in the nature, release odours, decrease the amount of dissolved oxygen in the waters and lead to the development of weeds and algae. Wastewater released to the environment without any treatment has also affected plant, animal, and human health negatively. In this study, characteristics and biogas potential of Extended Aeration Activated Sewage Sludge were defined using anaerobic treatment methods. Dry matter, organic dry matter, chemical oxygen demand, ammonium nitrogen and various heavy metal analyses were carried out and the obtained results throughout the study were presented.Öğe Determination of the new risk factors for predicting long term mortality in patients undergoing transfemoral tavi procedure: can the conventional risk scores be used as a long term mortality predictor(Oxford Univ Press, 2018) Alpaslan, E.; Dursun, H.; Tanriverdi, Z.; Colluoglu, T.; Kaya, D.[No abstract available]Öğe Energy exergy efficiencies and environmental effects of mixed fuelled (solid plus gas) industrial facility steam boiler(Elsevier Sci Ltd, 2013) Kaya, D.; Eyidogan, M.; Ozkaymak, M.; Turhan, F.; Kilinc, E.; Kayabasi, E.; Sahin, Z.In this paper, an experimental study has been performed for mixed (solid + gas) fuelled boiler operating at 7000 kPa pressure and 778.15 K temperature with a nominal capacity of 25 kg s(-1) in order to find improvement in the boiler efficiency and to reduce its environmental emissions. In this scope, while the boiler was working under operating conditions, temperature, pressure, velocity, and combustion gas measurements were performed and the measured data were used to establish mass and energy balance. Main efficiency loses were identified as operation of the boiler with high excess air factor (39.78%), leakage air in the rotary air hater and surface thermal losses. Calculations, were performed with the use of measured data, estimated that the boiler and second law efficiency were calculated as 85.3 and 39.6% respectively. When the injected heat value on water is 67 433.65 kW in the boiler, by the reduction of excess air factor is 550 kW and by the prevention of leakage air is 1251.6 kW, including totally saving amount is 1801.7 kW. Financial value of this saving was calculated about 309 465$.Öğe Energy saving and emission reduction opportunities in an industrial annealing furnaces(Gazi Universitesi Muhendislik-Mimarlik, 2014) Eyido?an, M.; Kaya, D.; Dursun, S.; Taylan, O.In this study, "energy efficiency" study has been performed for a LNG (Liquefied Natural Gas) fuel annealing furnace. Within this frame, temperature, pressure, velocity, and gas analysis measurements have been made and energy and mass balances have been formed. From the measured data, the furnace total efficiency was calculated as 52.76%. The main efficiency losses: operating furnace at high air excessiveness coefficient, inadequacy of air preheater heater (recuperator) heat transfer surface area and surface thermal losses.Öğe Evaluation of structural valve deterioration and bioprosthetic valve failure utilizing the new European consensus definition in patients undergoing TAVI with first-generation devices: Outcomes beyond 5 years from a single center in Turkey(Turkish Society of Cardiology, 2021) Sentürk, B.; Dursun, H.; Çöllüoglu, T.; Özdamar, H.; Ekin, T.; Tanriverdi, Z.; Kaya, D.Objective: The long-term durability of transcatheter aortic bioprosthetic valves continues to be a major concern. Standardized criteria of the structural valve deterioration (SVD) and bioprosthetic valve failure (BVF) have recently been defined. Limited studies have evaluated the long-term durability of transcatheter aortic valve implantation (TAVI) according to these new definitions. We aim to analyze the durability of TAVI beyond 5 years and to report the frequency of SVD and BVF. Methods: A total of 89 patients who had undergone TAVI and had theoretically completed at least 5 years after the procedure were included. Either a Medtronic CoreValve or an Edwards SAPIEN XT valve were implanted in the patients. New standardized definitions were used to evaluate SVD and BVF. Results: The mean age of the patients was 78.70±6.95 years. SVD occured in 4 (4.5%) patients during 6 years of follow-up. Severe SVD was observed in 2 patients (2.2%), and these patients had the New York Heart Association class II symptoms. Both patients with severe SVD also met the criteria of BVF. Moderate SVD was observed in 2 patients (2.2%), and these patients had no valve-related symptoms. Of the 4 SVD cases, 2 were associated with increased mean transaortic gradients, whereas the remaining 2 cases were associated with intraprosthetic aortic regurgitation. All patients with SVD are still alive, and none of them have required aortic valve reintervention. Conclusion: Although first-generation TAVI devices were used, we determined the low rate of SVD and BVF at the 6-year follow-up. It may be suggested that there is no major concern associated with TAVI even with first-generation devices regarding long-term durability. © Copyright 2021 by Turkish Society of Cardiology - Available online at www.anatoljcardiol.com
