Browsing by Author "Kurt, Merve"
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Item Open Access The concept of authenticity in the protection of industrial heritage : the case of Samsun Tobacco Factory Building(2014) Kurt, MerveThe gradual changes in almost all aspects of life brought about by the industrial developments left their spatial and social traces. These sometimes revolutionary variations have inscribed their identity in entire cities. The protection of these traces lies behind the protective thought and activities for cultural heritages. Industrial heritage, as one of the important constituents of the cultural heritage, has become a central issue for the world heritage protection activities. Within a historical perspective, through the late 18th and 19th centuries’ Industrial Revolution, all production processes and methods have seen radical changes and the new industrial technology affected the factories and manufacturing sites. These changes, however, were not confined to these past centuries. The rapid advancements in industry continued to force adjustments of these industrial sites or brought their abandonments. Today, there are many studies, groups, conferences, thus a powerful discourse upon the protection and re-evaluation of industrial heritage. In the protection and re-evaluation process, “authenticity” appears as an important concept. With this in mind, this study investigates the importance of authenticity within the concept of collective memory and analyses its status in the process of the industrial heritage protection in architecture. Through the case study of Samsun Tobacco Factory (1886), which was turned into a shopping mall in 2012, these arguments are developed and the analysis is made. This study aims to put a special emphasis on such sites as a value for the socio-cultural dynamics and historical sustainability of the urban life and bring a criticism upon their commercialized re-evaluation and reuse that may create incompatibilities with the spatial/architectural authenticity and with the collective memory of a city.Item Open Access Exothermic catalytic decomposition of energetic ionic liquids on iridium based catalysts(2022-01) Kurt, MerveHydrazine (N2H4) is the most commonly used propellant for in-orbit spacecraft propulsion. However, utilization of hydrazine in space missions has challenges associated with health, environment and safety risks. Energetic ionic liquids (EILs) such as ammonium dinitramide (ADN) present themselves as environmentally friendly alternative fuels to hydrazine. EILs can be decomposed efficiently and safely in the presence of a heterogenous catalyst. In this context, monometallic catalysts containing Ir and Al2O3 were synthesized using both wetness impregnation and incipient to wetness impregnation methods, and the structural properties of these catalysts were investigated. Furthermore, the effects of the Al2O3 support material on Ir dispersion and catalytic performance of anaerobic ADN decomposition were studied. In order to improve the Ir active site dispersion on the Al2O3 support material, promoters such as La and Ce were added to the catalyst systems and different pretreatment conditions were applied to the synthesized catalysts. Furthermore, LaMnO3 (perovskite) promoted alumina catalysts with Ir active sites were also studied. Catalysts with high performance, 5Ir/TH100 (5Ir/Al2O3), 5Ir/L3 (5Ir/La-Al2O3), and 5Ir/Sir10 (5Ir/Si-Al2O3) were investigated with in-situ X-ray Absorption Near Edge Spectroscopy (XANES), in-situ Extended X-ray Absorption Fine Structure (EXAFS), in-situ Fourier Transform Infrared Spectroscopy (in-situ FTIR), Temperature Programmed Desorption (TPD), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Energy Dispersive X-ray (EDX), Pyridine adsorption via FTIR, CO Chemisorption, X-ray Photoelectron Spectroscopy (XPS) and X-ray Fluorescence (XRF) analysis techniques. Our findings revealed that 5Ir/TH100 and 5Ir/L3 catalysts favorably lowered the onset temperature of the ADN decomposition reaction, whereas 5Ir/Sir10 boosted the pressure generation during the reaction. The formation of mostly metallic Ir nanoparticles on 5Ir/TH100 and 5Ir/L3 enables the lowering of the activation energy of the reaction. On the other hand, enhancement in the pressure generation for 5Ir/Sir10 catalyst is associated with the generation of small oxidic Irn x+ clusters which are strongly interacting with the SiOx-AlOx surface domains of the support material. The fundamental structure-functionality relationships unraveled in the current work may allow design of novel catalytic systems for aerospace monopropellant propulsion systems with higher performance by simultaneous exploitation of Ir active sites with different electronic properties.Item Open Access Influence of La and Si promoters on the anaerobic heterogeneous catalytic decomposition of ammonium dinitramide (ADN) via alumina supported iridium active sites(Elsevier, 2022-02-25) Kurt, Merve; Kap, Zeynep; Senol, Sinem; Ercan, Kerem Emre; Sika-Nartey, Abel Tetteh; Kocak, Yusuf; Koc, A.; Esiyok, H.; Caglayan, B. S.; Aksoylu, A. E.; Ozensoy, EmrahStructural origins of the promotional effects of the La or Si doping of alumina supported Ir catalysts in anaerobic ammonium dinitramide decomposition were investigated. Our findings reveal that Ir/Al2O3 and Ir/La-Al2O3 favorably lower the onset temperature of the ADN decomposition reaction, whereas Si doping boosts the pressure generation during the reaction. Formation of mostly metallic Ir nanoparticles for Ir/Al2O3 and Ir/La-Al2O3 enables the lowering of the activation energy of the reaction. On the other hand, enhancement due to Si promotion is associated to the generation of small oxidic Irnx+ clusters which are strongly interacting with the SiOx-AlOx surface domains of the support material. Fundamental structure-functionality relationships unraveled in the current work may allow design of novel catalytic systems for aerospace monopropellant propulsion systems with higher performance by simultaneous exploitation of Ir active sites with different electronic properties.Item Open Access Trade-off between NOx storage capacity and sulfur tolerance on Al2O3/ZrO2/TiO2–based DeNOx catalysts(Elsevier, 2019) Say, Zafer; Mihai, O.; Kurt, Merve; Olsson, L.; Özensoy, EmrahAl2O3/ZrO2/TiO2 (AZT) ternary mixed oxides functionalized with Pt and BaO were synthesized in powder and monolithic forms and were utilized in NOx Storage Reduction/Lean NOx Trap (NSR/LNT) catalysis as novel catalytic materials. Adsorption of NOx and SOx species and their interactions with the catalyst surfaces were systematically investigated via in-situ FTIR technique revealing different NOx coordination geometries governed by the presence and the loading of BaO in the powder catalyst formulation. While BaO-free Pt/AZT stored NOx as surface nitrates, BaO incorporation also led to the formation of bulk-like ionic nitrate species. NOx adsorption results obtained from the current Temperature Programmed Desorption (TPD) data indicated that NOx Storage Capacity (NSC) was enhanced due to BaO incorporation into the powder catalyst and NSC was found to increase in the following order: Pt/AZT < Pt/8BaO/AZT < Pt/20BaO/Al2O3 < Pt/20BaO/AZT. Increase in the NSC with increasing BaO loading was found to be at the expense of the formation of bulk-like sulfates after SOx exposures. These bulk-like sulfates were observed to require higher temperatures for complete regeneration with H2(g). Catalytic activity results at 473 K and 573 K obtained via flow reactor tests with monolithic catalysts suggested that Pt/AZT and Pt/8BaO/AZT catalysts with stronger surface acidity also revealed higher resistance against sulfur poisoning and superior SOx regeneration in spite of their relatively lower NSC. Monolithic Pt/ 20BaO/AZT catalyst revealed superior NSC with respect to the conventional Pt/20BaO/Al2O3 benchmark catalyst at 573 K after sulfur regeneration. On the other hand, this trend was reversed at high-temperatures (i.e. 673 K). Preliminary results were presented demonstrating the enhancement of the high-temperature NSC of AZTbased materials by exploiting multiple NOx-storage components where BaO functioned as the low/mid-temperature NOx-storage domain and K2O served as the high-temperature NOx storage domain. Enhancement in the high-temperature NOx-storage in the BaO-K2O multiple storage domain systems was attributed to the formation of additional thermally stable bulk-like nitrates upon K2O incorporation.