Browsing by Author "Gülçimen, Sedat"

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Characterizing boron-enhanced one-part alkaline-activated mortars: Mechanical properties, microstructure and environmental impacts
(ELSEVIER, 2024) Örklemez, Ezgi; İlkentapar, Serhan; Durak, Ugur; Gülçimen, Sedat; Uzal, Niğmet; Uzal, Burak; Karahan, Okan; Atiş, Cengiz Duran; 0000-0002-8967-3484; 0000-0002-3810-7263; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü; Gülçimen, Sedat; Uzal, Niğmet; Uzal, Burak
Since alkali activators negatively effect the environmental impact assessment, it is necessary to develop the alternative activators from natural sources with low environmental impact. Therefore, in this study, the usage of boron refined products colemanite, ulexite and boron pentahydrate as activators in slag-based alkali-activated mortar systems was investigated in detail. Flexural and compressive strength tests, isothermal calorimetry measurement, thermogravimetric and differential thermal analysis, inductively coupled plasma mass spectrometry analysis, field emission scanning electron microscopy, and energy dispersive analysis and elemental mapping and X-ray diffraction analysis were carried out on the samples. In addition, sample production was subjected to life cycle analysis (LCA) with a cradle-to-gate approach using two different transportation scenarios. According to the results obtained, it was determined that colemanite, ulexite and boron penta hydrate, when used in optimum proportions, had a positive effect on strength (up to increase 40% compressive strength by 20% ulexite replacement) and could be used as an activator in slag-based alkali-activated systems. The positive results obtained in strength as a result of using boron-refined products are also supported by other test results conducted within the scope of the study. Furthermore, according to the LCA results, it was observed that there was a significant decrease in global warming potential with the substitution of 20% colemanite, ulexite or boron pentahydrate as activators, not only compared to the reference sample but also traditional cementitious systems.
A life cycle approach for sustainable and energy efficient urban transport
(Abdullah Gül Üniversitesi / Fen Bilimleri Enstitüsü / Sürdürülebilir Kentsel Altyapı Mühendisliği Ana Bilim Dalı, 2021) Gülçimen, Sedat; AGÜ, Fen Bilimleri Enstitüsü, Sürdürülebilir Kentsel Altyapı Mühendisliği Ana Bilim Dalı
The objective of this thesis study is to evaluate the sustainability of the urban transport system in Kayseri. In the first part, a life cycle sustainability assessment (LCSA) of the tramway system was performed using a cradle‐to‐grave approach by integrating the environmental, economic, and social aspects for the case of Kayseri, Turkey. The LCSA results revealed that the operation and maintenance phase were determined as the main contributor to the environmental load of the tramway system within its entire life cycle. For economic assessment, the main contributor to the total life cycle cost was energy cost. In the social performance evaluation, it is found that the industry performs well for society, the local community, and workers but has a weaker social performance for the consumer due to a weak feedback mechanism. In the second part, urban transport alternatives were evaluated with the integration of Hesitant Fuzzy Analytical Hierarchy Process (HF-AHP) and Multiple Attribute Utility Models (MAUT) methods. Eight sustainable transport indicators were selected and the weights of selected indicators are calculated with the utilization of HF-AHP. Based on HF-AHP results, the number of fatalities/injuries has been determined as the most significant indicator among the eight indicators with 0.158 normalized weight. Then, twelve urban transport alternatives were ranked by using the MAUT method to decide the most sustainable urban transport alternative. The results of this integrated methodology present that alternative 11, which is dominated by low-motorized vehicles, has been determined as the best sustainable alternative and alternative 1 is the worst sustainable alternative which is dominated by high-motorized vehicles with 0.69 and 0.27 of total utility values, respectively.
Wind farm site selection using GIS-based multicriteria analysis with Life cycle assessment integration
(SPRINGER, 2024) Demir, Abdullah; Dinçer, Ali Ersin; Çiftçi, Cihan; Gülçimen, Sedat; Uzal, Nigmet; Yılmaz, Kutay; 0000-0002-6392-648X; 0000-0002-4662-894X; 0000-0001-9199-6437; 0000-0002-8967-3484; 0000-0002-0912-3459; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü; Demir, Abdullah; Dinçer, Ali Ersin; Çiftçi, Cihan; Gülçimen, Sedat; Uzal, Nigmet
The sustainability of wind power plants depends on the selection of suitable installation locations, which should consider not only economic and technical factors including manufacturing and raw materials, but also issues pertaining to the environment. In the present study, a novel methodology is proposed to determine the suitable locations for wind turbine farms by analyzing from the environmental perspective. In the methodology, the life cycle assessment (LCA) of wind turbines is incorporated into the decision process. The criteria are ranked using analytical hierarchy process (AHP). The study area is chosen as the western region of Türkiye. The obtained suitability map reveals that wind speed is not the sole criterion for selecting a site for wind turbine farms; other factors, such as bird migration paths, distance from urban areas and land use, are also crucial. The results also reveal that constructing wind power plants in the vicinity of İzmir, Çanakkale, Istanbul, and Balıkesir in Türkiye can lead to a reduction in emissions. İzmir and its surrounding area show the best environmental performance with the lowest CO2 per kilowatt-hour (7.14 g CO2 eq/kWh), to install a wind turbine due to its proximity to the harbor and steel factory across the study area. Çanakkale and the northwest region of Türkiye, despite having high wind speeds, are less environmentally favorable than İzmir, Balıkesir, and Istanbul. The findings of LCA reveal that the nacelle and rotor components of the wind turbine contribute significantly (43–97%) to the environmental impact categories studied, while the tower component (0–36%) also has an impact.