İnşaat Fakültesi

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http://hdl.handle.net/11527/16710

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  • Öge
    9. Türkiye Deprem Mühendisliği Konferansı Bildiriler Kitabı, 2-3 Haziran 2021, İstanbul
    (TMMOB, Türkiye Deprem Vakfı, 2021-06-02) İnşaat Mühendisliği ; Tönük, Gökçe ; Dalgıç, Korhan Deniz ; Halıcı, Ömer Faruk
    Depremde oluşan yapısal hasar dağılımları ile yerel zemin koşulları arasında yakından ilişki olduğu gözlenmiştir. Son 60-70 yılda hasar dağılımları yanında, aletsel ölçümlerle de kanıtlanan bu ilişki, çok disiplinli deprem mühendisliği dalında içinde geoteknik deprem mühendisliği alt dalının gelişmesine yol açmıştır. Yerel zemin koşullarının deprem etkisinde yapısal davranış üzerinde etkileri iki ana başlık altında toplanabilmektedir: (1) tekrarlı(çevrimli) deprem yükleri altında temel zemininde ortaya çıkabilecek taşıma gücü kaybı, aşırı oturmalar ve yer değiştirmeler; (2) deprem hareketi özelliklerinde meydana gelen değişimler ve buna bağlı olarak yapının maruz kaldığı sarsıntı şiddeti ve atalet kuvvetlerinde meydana gelen değişimler. Deprem hasarlarının azaltılmasına yönelik çalışmalarda deprem yükleri etkisinde zeminlerin davranışının incelenmesi (dinamik zemin özelliklerinin belirlenmesi) için laboratuvar deney yöntemlerinde önemli gelişmeler yaşanırken, zemin davranışını modellemeye yönelik bünye denklemleri ve analiz yöntemleri de geliştirilmiştir.
  • Öge
    A C0 continuous mixed FE formulation for bending of laminated composite plates based on unified HSDT
    (Wiley, 2024) Bab, Yonca ; Kutlu, Akif ; orcid.org/0000-0002-1807-9306 ; orcid.org/0000-0001-6865-3022 ; İnşaat Mühendisliği
    This study proposes a unified C0 continuous mixed finite element (MFE) formulation for the accurate and efficient prediction of stress components in laminated composite plates relying on Higher Order Shear Deformation Theory (HSDT). This unified form of the MFE accepts any convenient function for the representation of transverse shear deformation. The Hellinger–Reissner variational principle is employed for the derivation of MFE equations within a two-field formulation involving stress resultants along with kinematical variables. Thus, the displacement and stress resultant fields are obtained directly from the global solution of the system of equations. In this manner, the in-plane stress components are calculated over constitutive relations at the nodes without any need for error-prone spatial derivatives. Furthermore, the independent interpolation of kinematic and stress resultant type variables allows the numerical solution to overcome the shear-locking problem and ensure C0 continuity requirement. Numerical examples include convergence and comparison tests of predicted displacements and stress components under various boundary conditions and material configurations. Various test cases are considered for both the thin and thick plates subjected to sinusoidal and uniformly distributed loads. It is demonstrated that the proposed MFE formulation can capture stress components with high accuracy while being computationally efficient.
  • Öge
    An integrated groundwater vulnerability and artificial recharge site suitability assessment using GIS multi-criteria decision making approach in Kayseri region, Turkey
    (Springer, 2024) Mouhoumed, Rachid Mohamed ; Ekmekçioğlu, Ömer ; Özger, Mehmet ; 0000-0001-7346-4699 ; 0000-0002-7144-2338 ; İnşaat Mühendisliği
    Groundwater resources worldwide face significant challenges that require urgent implementation of sustainable measures for effective long-term management. Managed aquifer recharge (MAR) is regarded as one of the most promising management technologies to address the degradation of groundwater resources. However, in urban aquifers, locating suitable areas that are least vulnerable to contamination for MAR implementation is complex and challenging. Hence, the present study proposes a framework encapsulating the combined assessment of groundwater vulnerability and MAR site suitability analysis to pinpoint the most featured areas for installing drywells in Kayseri, Turkey. To extrapolate the vulnerable zones, not only the original DRASTIC but also its multi-criteria decision-making (MCDA)–based modified variants were evaluated with regard to different hydrochemical parameters using the area under the receiver operating characteristic (ROC) curve (AUC). Besides, the fuzzy analytical hierarchy process (FAHP) rationale was adopted to signify the importance level of criteria and the robustness of the framework was highlighted with sensitivity analysis. In addition, the decision layers and the attained vulnerability layer were combined using the weighted overlay (WOA). The findings indicate that the DRASTIC-SWARA correlates well with the arsenic (AUC = 0.856) and chloride (AUC = 0.648) and was adopted as the vulnerability model. Groundwater quality parameters such as chloride and sodium adsorption ratio, as well as the vadose zone thickness, were found to be the most significant decision parameters with importance levels of 16.75%, 14.51%, and 15.73%, respectively. Overall, 28.24% of the study area was unsuitable for recharge activities with high to very high vulnerability, while the remaining part was further prioritized into low to high suitability classes for MAR application. The proposed framework offers valuable tool to decision-makers for the delineation of favorable MAR sites with minimized susceptibility to contamination.
  • Öge
    Analysis of particle size distribution of organic carbon for landfill leachate : implications for sustainable treatment
    (Wiley, 2023) Doğruel, Serdar ; Kaya, Beste ; Soylu, Dilşad ; Çokgör, Emine ; Baran, Aydın ; Sözen, Seval ; Orhon, Derin ; orcid.org/0000-0003-4214-8436 ; orcid.org/0000-0001-6158-4132 ; orcid.org/0000-0002-5417-0318 ; orcid.org/0000-0002-4904-6056 ; orcid.org/0000-0003-2027-604X ; orcid.org/0000-0002-6823-3498 ; Çevre Mühendisliği
    BACKGROUND Landfill leachate has a complex composition requiring experimental support to formulate a sustainable treatment strategy. This study utilized the particle size distribution (PSD) of the chemical oxygen demand (COD) content to assess the profile of biodegradable and inert COD fractions; it also emphasized the functions and benefits of ultrafiltration and nanofiltration modules coupled to an activated sludge process. The evaluation profited from the field data of a landfill site in Istanbul, where the leachate was actually treated in a membrane bioreactor (MBR) plant. RESULTS COD and total nitrogen levels fluctuated between 10 100–31 200 mg L−1 and 1150–2800 mg L−1, respectively. PSD analysis for COD, conducted at two extremes, displayed similar results, where the majority of the COD was observed to accumulate at the low extremity of the particle size, 70–72% below 2 nm. Therefore, direct membrane filtration of leachate yielded low COD removals that were limited to 9% with ultrafiltration and to 31–35% with nanofiltration. COD fractionation indicated a ratio of 5% for the inert COD in leachate. The permeate COD of ultrafiltration in the existing plant was 2000 mg L−1, much higher than the inert fraction ratio, which was further reduced to 266 mg L−1 by nanofiltration. CONCLUSION PSD analysis was an integral complement of respirometry for establishing the size-biodegradation relationships of different COD fractions. It located the majority of soluble COD fractions below 0.55 nm, thus implying the necessity of a biological process. PSD also identified the generation of soluble residual metabolic products, indicating that residual COD escaping treatment would be equally significant to the removal potential of the biodegradable substrate.
  • Öge
    Assessment of Microbial Diversity during Thermophilic Anaerobic Co-Digestion for an Effective Valorization of Food Waste and Wheat Straw
    ( 2022-12-21) Yangın Gömeç, Çiğdem ; Agnihotri, Swarnima ; Ylitervo, Päivi ; Sárvári Horváth, Ilona ; 0000-0003-3519-4821 ; Environmental Engineering
    In this study, predominant bacterial and archaeal populations and their roles during anaerobic mono-digestion of food waste (FW) and co-digestion of FW with straw pellets (SP) at thermophilic temperature (53 ± 1 °C) were assessed by Next Generation Sequencing (NGS) analysis at organic loading rates (OLRs) of 3.0 and 7.0 gVS/L/d. Depending on the seed; results revealed that Firmicutes, Bacteroidetes, and Proteobacteria were, respectively the most prevalent bacterial phyla at both OLRs investigated. On the other hand, Euryarchaeota was dominated by methanogens playing crucial role in biogas production and correlated mainly with the activities of Methanobacteria and Methanomicrobia at class level. Acetoclastic Methanosaetae was the predominant genus at OLR = 3.0 gVS/L/d; however, shared the same predominance with hydrogenotrophic methanogens Methanospirillium at the highest OLR. Although no clear effect in response to straw addition at OLR of 3.0 gVS/L/d could be seen in terms of methanogenic archaea at genus level, hydrogenotrophic methanogens revealed some shift from Methanobacterium to Methanospirillium at higher OLR. Nevertheless, no prominent microbial shift in the presence of wheat straw at increased OLR was likely due to adapted inoculation at start-up which was also demonstrated by relatively stable biogas yields during co-digestion.
  • Öge
    CICE 2020/2021 Abstract Book
    (International Institute for FRP in Construction, 2021-12-08) Ilki, Alper ; Ispir, Medine ; Inci, Pınar
    This book includes the abstracts of 216 papers from 34 countries and other relevant information about CICE 2020/2021 conference. The great contributions of our keynote speakers, invited theme lecturers and all speakers are highly appreciated. The quality of the contributions submitted to CICE 2020/2021 was very high, and as organizers we had the chance to invite more than 100 papers to special collections/issues of ASCE Journal of Composites for Construction, Construction and Building Materials Journal, and Turkish Journal of Civil Engineering based on the suggestions of the reviewers
  • Öge
    Combination of ozonation with GAC, AIX and biochar post-treatment for removal of pharmaceuticals and transformation products from municipal WWTP effluent
    (Royal Society of Chemistry, 2024) Fakioglu, Malhun ; Golovko, Oksana ; Baresel, Christian ; Ahrens, Lutz ; Öztürk, İzzet ; https://orcid.org/0000-0003-1475-2249 ; https://orcid.org/0000-0002-8274-5326 ; Çevre Mühendisliği
    Pharmaceuticals have been detected in water and wastewater, resulting in increasing research attention towards the elimination of these substances from aqueous environments. Due to the limitations of conventional processes in wastewater treatment plants (WWTPs) to fully eliminate these compounds, more research is needed on complementary advanced treatment technologies. This study aims to examine the removal efficiency for 24 selected pharmaceuticals and the fate of their 7 main metabolites including several oxidation transformation products by various technique combinations applied on the effluent from a full-scale WWTP. Investigated treatment options include ozonation (O3) combined with either granular activated carbon (GAC), two different types of biochar, and anion exchange (AIX) in a continuously operated laboratory-scale system. The average removal of analyzed pharmaceuticals ranged between 8.8–97% with an O3 dose of 0.28 g O3/g DOC (dissolved organic carbon), whereas it ranged from 86–99% for higher O3 dosages (0.96 and 2.17 g O3/g DOC). Overall, the investigated metabolites of pharmaceuticals exhibited lower removal efficiency (between −33 and 99%) with ozone compared to the parent compounds at all O3-dosages. Concentrations of oxidation transformation products such as citalopram N-oxide were increased after ozone treatment, whereas it was decreased after the columns at different rates. The bromate concentrations during all three O3-dosages (0.28, 0.96 and 2.17 g O3/g DOC) were below 5 μg L−1. GAC was the best performing sorbent among all materials, where even after two weeks of continuous operation, nearly all compounds were removed below quantification levels. Although biochar 1 showed better performance (30–89%, mean = 68%) than biochar 2 (8.5–82%, mean = 38%), both sorption materials showed reduced sorption capacity over the time period of two weeks for most of the target compounds. On the other hand, AIX had lower removal rates ranging between 2–55% (mean = 20%). Regarding the combination of O3 with the individual sorbent materials, GAC was the most successful combination with O3 for the removal of pharmaceuticals (>99%) and oxidation transformation products (>60%). The combination of O3 with biochar 1 was more successful (mean = 91%) than the combination with biochar 2 (mean = 79%), where the combination of O3 with AIX showed the lowest removal rates (mean = 58%).
  • Öge
    Deprem risk yönetiminde yazılım ve deprem mühendisliği çalıştayı bildiriler kitabı
    (İTÜ Yayınevi, 2022-05-26) Deprem Risk Yönetiminde Yazılım ve Deprem Mühendisliği Çalıştayı: 2022 ; İnşaat Mühendisliği ; Baş, Selçuk ; Püskülcü, Seyhun ; İlki, Alper ; Akşit, Mehmet
    "Deprem olgusu, ülkemiz için göz ardı edilemeyecek bir gerçekliktir. Son yıllarda yazılım, sistem mühendisliği ve yapay zekâ alanlarında gözlemlenen gelişmeler, deprem mühendisliği alanında yürütülen çalışmalarda da etkinliğini arttırmaktadır. Bu amaçla, ülkemizde deprem mühendisliği alanında yurtiçi/yurtdışı birçok bilimsel aktiviteye öncülük eden Türkiye Deprem Vakfı (TDV), deprem risklerinin yönetimi konusunda yazılım mühendisliği ve deprem mühendisliği alanlarında çalışan uzmanları bir araya getirmek amacıyla 26 Mayıs 2022 tarihinde, “Deprem Risk Yönetiminde Yazılım ve Deprem Mühendisliği (YDMÇ-2022)" çalıştayını çevrim içi olarak düzenlemiştir. Çalıştaya internet üzerinden 252 kişi kaydolmuştur. Bizim tespitlerimize göre, bu toplantı sözü geçen konuda dünyada düzenlenen ilk çalıştaydır."
  • Öge
    Design and nonlinear dynamic response of a steel stack
    (Springer, 2024) Vatansever, Cüneyt ; Çayır, Haşim ; 0000-0002-9954-925X ; 0000-0001-8131-4703 ; İnşaat Mühendisliği
    Industrial stacks are built in order to reduce atmospheric pollution and release gases to the higher level of the atmosphere. Since they are high and slender structures, they are significantly affected by lateral forces, in particular, induced by winds and earthquakes. This paper aims to summarize the design principles for steel stacks given in the international standards, codes and specifications considering the evaluation of the results from the investigation on nonlinear dynamic response of a typical steel stack subjected to the earthquake. For this purpose, a typical self-supporting steel stack has been designed and its performance under earthquake and wind forces has been investigated in terms of the applied design principles, such as the displacement limit and the potential plastic deformations. The study is accomplished by using finite element models employing nonlinear time history and pushover analyses. The numerical results are presented particularly by considering the design principles used for the model. The results show that wind loads considered are more pronounced in the design of industrial steel stacks than earthquake especially in terms of limiting top displacement. The flue openings which reduce strength and lateral stiffness of the stack web is significantly effective in the lateral behavior of the stack. Moreover, the principles considered are found applicable for the design of such steel stacks. Based on the results from nonlinear time history analyses, no yielding and plastic deformation are detected along the stack.
  • Öge
    Developing GeoAI ıntegrated mass valuation model based on LADM valuation ınformation Great Britain country profile
    (Wiley, 2024) Mete, Muhammed Oğuzhan ; orcid.org/0000-0002-9312-1965 ; Geomatics Engineering
    Access to information pertaining to land facilitates strategic planning for individuals, businesses, and governmental entities and allows them to anticipate and address contemporary challenges such as climate change, housing requirements, and economic prosperity. Improvements in information technologies contribute to data creation, analysis, and dissemination processes that enable gaining knowledge about land-related events. Greater use of location data within property technologies gives rise to an efficient and sustainable land administration system. GeoAI can contribute greatly to the solution of spatial problems by extracting information from complex data through geospatial intelligence. Property valuation requires a spatially explicit model to evaluate locational factors with spatial analyses. In this study, a Land Administration Domain Model (LADM)-based mass valuation model is developed for Great Britain by integrating GeoAI techniques. First, the LADM Valuation Information package is matched with the country's current organizational structure and it is extended according to the needs to create a country profile. After developing the conceptual model, a database schema is created and automatic conversion to the physical model is conducted. Loading different data sources into the database, a mass valuation application is carried out through spatial analysis and Random Forest regression analysis. As a result, a highly accurate and holistic valuation model is implemented based on the international land administration standards.
  • Öge
    Disaster management with cloud-based geographic information systems : site selection of landfill areas after Kahramanmaraş, Türkiye earthquake sequence
    (Springer, 2024) Mete, Muhammed Oğuzhan ; Bıyık, Muhammed Yahya ; 0000-0002-9312-1965 ; 0000-0001-9848-9673 ; Harita Mühendisliği
    On February 6, 2023, the earthquakes centered on Kahramanmaraş-Pazarcık and Kahramanmaraş-Elbistan affected several provinces in the region and generated a vast amount of demolition waste. This study aims to develop a site selection model for the most suitable landfill areas after the earthquake using open-source Geographic Information Systems (GIS) software and the Best-Worst Method (BWM). First, the study identifies decision criteria with a Delphi expert panel. Next, it determines the weights using the BWM based on pairwise comparison. Spatial data of the determinants were obtained from open data portals, and proximity, overlay, and slope analyses were carried out for the disaster region. Combining the output data layer of each criterion, a suitability map of the landfills was produced. As a result, 36,2% (29,826 kms square) of the study area was classified as suitable and very suitable. In this study, a cloud GIS-based decision support platform was developed to act quickly and initiate recovery processes within the scope of disaster management of the destructive earthquake. The suitability map and potential sites were shared with the responsible teams in the disaster area so that the potential sites could be displayed on the map and the suitable areas could be navigated on appropriate routes. The findings of the study revealed that the use of open data and cloud GIS framework in the disaster management process enables quick, reliable, and cost-effective actions in the immediate aftermath of disasters.
  • Öge
    Effect of photocatalytic pretreatment on the membrane performance in nanofiltration of textile wastewater
    (Springer, 2024) Korkut, Sevde ; Ormancı-Acar, Türkan ; Keskin, Başak ; Ağtaş, Meltem ; Karahan, Özlem ; Demir, Tuğba U. ; Ünal, Serkan ; Menceloğlu, Yusuf Z. ; Koyuncu, İsmail ; Çevre Mühendisliği
    Traditional methods like biological treatment, flocculation-coagulation, adsorption, and advanced oxidation are commonly employed for textile wastewater treatment, but their sustainability is hindered by issues such as the adverse impact of textile wastewater on microorganisms and the requirement for substantial chemical usage. In response to increasingly stringent legal discharge standards, membrane technologies are emerging as prominent alternatives for effective textile wastewater treatment. The application of photocatalysis as a pretreatment to improve effluent quality and treatment performance has shown effective results in the treatment of textile wastewater by nanofiltration (NF). However, innovative solutions are needed to improve the efficiency of UV photocatalytic reactors. Here, the TiO2/halloysite nanotube (HNT) photocatalyst was shown to completely remove dyes under UV illumination. Two wastewater samples from photocatalytic (PC) pretreatment were treated using innovative NF membranes with different contents. The study examined the impact of PC pretreatment on the flux of wastewater from a textile factory heat recovery tank, which increased from 18.32 to 27.63 L/m2.h. The membranes achieved > 98% removal in COD, while bare membrane achieved 95% removal in conductivity. The addition of s-DADPS as monomer and HNT as nanoparticles to the membranes with different compositions affected the cross-linking in the TFC layer. During the tests conducted on the water extracted from the dyeing tank, the color was completely eliminated without any loss of flux. Additionally, improvements in COD removal were observed.
  • Öge
    Energy Production from Biomass Valorization
    ( 2023-05-24) Yangın Gömeç, Çiğdem ; Sárvári Horváth, Ilona ; Martin, Carlos ; 0000-0003-3519-4821 ; Environmental Engineering
  • Öge
    Enhanced energy recovery in municipal wastewater treatment plants through co-digestion by anaerobic membrane bioreactors : current status and future perspectives
    (Springer, 2024) Cengiz, Ali İzzet ; Güven, Hüseyin ; Özgün, Hale ; Erşahin, Mustafa Evren ; 0000-0002-4715-9567 ; 0000-0001-6754-0106 ; 0000-0001-8784-8351 ; 0000-0003-1607-0524 ; Çevre Mühendisliği
    Today, the transition to renewable energy from conventional energy practices is more important than ever to establish energy security and mitigate climate change. The wastewater treatment plants (WWTP) consume a remarkable amount of energy and cause significant greenhouse gas emissions. The energy balance of WWTP can be improved by implementing energy-efficient applications such as anaerobic digestion. However, most of the existing WWTPs utilize only sewage sludge in conventional anaerobic digesters (CAD) which results in low biogas generation. Generally, co-digestion is indicated as an effective solution for the low biogas generation faced in mono-digestion. Moreover, recently, anaerobic membrane bioreactors (AnMBR) have been promoted as a prominent alternative to CADs. This paper overviews the current situation of co-digestion applications by AnMBRs for municipal WWTPs. Furthermore, the environmental and economic aspects of these applications were reviewed. Lastly, challenges and future perspectives related to the co-digestion applications by AnMBR were thoroughly discussed.
  • Öge
    fib Symposium 2023, Istanbul - Building for the future : durable, sustainable, resilient : book of abstracts
    (İTÜ Yayınevi, 2023) İnşaat Mühendisliği ; İlki, Alper ; Çavunt, Derya ; Çavunt, Yavuz Selim
    Concrete is a widely used material in the construction industry due to its versatility, strength, and durability. However, the production of concrete has a significant impact on the environment, contributing to carbon emissions, resource depletion, and waste generation. This has led to an increasing need to address sustainability concerns in the construction industry. As the world population grows and the impact of climate change becomes more severe, the demand for sustainable buildings has also increased. Sustainable buildings minimize their environmental impact by reducing resource consumption, minimizing waste generation, and improving energy efficiency. Moreover, durable and resilient structures are crucial aspects of sustainable construction. Structures that can withstand the test of time and natural disasters reduce the need for frequent repairs and replacements, thereby reducing the resources needed for ongoing maintenance. Sustainable structures also provide long-term financial benefits by reducing operational costs. This is achieved through measures such as energy-efficient designs and the use of sustainable materials. In this aspect, it is essential for the construction industry to prioritize sustainability to ensure a better future for the world.
  • Öge
    Filling the ponds of Hattuşa - a geohydrological approach to determine inflows by time and volume
    (Springer, 2024) Wittenberg, Hartmut ; Aksoy, Hafzullah ; 0000-0001-6467-1194 ; 0000-0001-5807-5660 ; İnşaat Mühendisliği
    In the ruins of Hattuşa, the capital of the Hittite Empire more than 3,000 years ago, large, sedimented water storage ponds have been uncovered since 1998. An investigation based on time series of measured groundwater levels, showed that the ponds were supplied from layered aquifers which were opened at their source horizons directly at the uphill edge of the pond. When the groundwater level at the pond exceeds a threshold given by the geology at that edge, water pours into the pond. The principles and the path of filling become clear, but not the volumes and time distribution of the transfers. These results of the previous studies were amply published and are shortly summarized. The present investigation is also based on the time series of groundwater levels and of the discharge of a modern fountain as well as the local hydrogeological properties. The approach is simple but shows the effect of storage in the aquifer which delays the outflow into the pond, so that water from the rainy season was available in the dry season. Also, the annual outflow values are determined. Besides gaining knowledge it is an aim of the article to encourage interdisciplinary and process-oriented thinking.
  • Öge
    Formative drought rate to quantify propagation from meteorological to hydrological drought
    (Wiley, 2024) Yıldırım, Işılsu ; Aksoy, Hafzullah ; Hrachowitz, Markus ; orcid.org/0000-0002-4064-624X ; orcid.org/0000-0001-5807-5660 ; orcid.org/0000-0003-0508-1017 ; İnşaat Mühendisliği
    In this study, we propose a probabilistic metric, the formative drought rate (FDR), to quantify drought propagation. It is the probability that a meteorological drought in precipitation forms a hydrological drought in streamflow. Drought events were identified based on the standardized precipitation index and streamflow drought index, respectively, at 1-, 3-, 6- and 12-month timescales. The method was tested in three river basins in Turkey (Kucuk Menderes, Gediz and Ergene). In each river basin, meteorological stations were coupled with streamflow gauging stations to form pairs of stations depending on their distance from each other and the length of their common record periods. The FDR was calculated across all timescales for each pair of stations. It was found capable to describe the river basin-specific spatial and temporal variability of drought propagation. As the FDR is defined in the form of probability, it is expected to be a useful metric for quantifying propagation from meteorological to hydrological drought. Thus, it carries a potential for scientific research and practice in water resources management.
  • Öge
    Fresh, setting, and hardened properties of fly ash concrete with nano-silica
    (Springer, 2024) Baran, Servan ; Baran, Ahmet ; Bıçakcı, Sidar Nihat ; Turkmenoğlu, Hasan Nuri ; Atahan, Hakan Nuri ; 0000-0003-2136-149X ; 0000-0002-1545-0376 ; 0000-0003-4765-8590 ; 0000-0002-7917-3021 ; İnşaat Mühendisliği
    Nano-silica (NS) may counteract the drawbacks of fly ash (FA), such as delayed setting and low early strength, by accelerating hydration and providing higher early strength in concrete. In this study, concrete mixtures having 4 different FA replacement ratios (0%, 20%, 35%, and 50% by vol.) and 3 different NS dosages (0%, 1.7%, and 3.4% by vol.) were prepared. Effect of NS on the rheology, setting times and temperature evolution during the setting period, microstructure, compressive strength, and modulus of elasticity (MOE) of concrete at constant slump (20 ± 1 cm) were investigated. Plasticizers influenced the rheological and setting properties of concrete designed at constant consistency. In terms of these properties, although there have been cases where the use of NS has shown controversy results compared to the common knowledge in literature, this situation has been associated with the demand for the plasticizers consumed to obtain constant slump. In general, NS accelerated the setting times of concrete, however, it could not completely tolerate the delay caused by FA. According to 7-day mechanical test results, using 3.4% NS almost fully recovered the 20% strength loss caused by 20% FA replacement. Even if compressive strength close to NS-free REF mixture could not be achieved with high volume FA replacement (50%), at 7 days, MOE results, comparable to NS-free REF concrete, could be achieved using 3.4% NS. At later ages, although the compressive strength varied over a wide range, i.e., from 30 to 75 MPa, MOE of FA concrete have become almost independent of the strength.
  • Öge
    Impact of food waste addition in energy efficient municipal wastewater treatment by aerobic granular sludge process
    (Springer, 2024) Çiçekalan, Büşra ; Berenji, Nastaran Rahimzadeh ; Aras, Muhammed Furkan ; Güven, Hüseyin ; Koyuncu, İsmail ; Erşahin, Mustafa Evren ; Özgün, Hale ; 0000-0002-1806-9917 ; 0000-0001-6431-383X ; 0000-0002-0811-9001 ; 0000-0001-6754-0106 ; 0000-0001-8354-1889 ; 0000-0003-1607-0524 ; 0000-0001-8784-8351 ; Çevre Mühendisliği
    Recently, one of the main purposes of wastewater treatment plants is to achieve a neutral or positive energy balance while meeting the discharge criteria. Aerobic granular sludge (AGS) technology is a promising technology that has low energy and footprint requirements as well as high treatment performance. The effect of co-treatment of municipal wastewater and food waste (FW) on the treatment performance, granule morphology, and settling behavior of the granules was investigated in the study. A biochemical methane potential (BMP) test was also performed to assess the methane potential of mono- and co-digestion of the excess sludge from the AGS process. The addition of FW into wastewater enhanced the nutrient treatment efficiency in the AGS process. BMP of the excess sludge from the AGS process fed with the mixture of wastewater and FW (195 ± 17 mL CH4/g VS) was slightly higher than BMP of excess sludge from the AGS process fed with solely wastewater (173 ± 16 mL CH4/g VS). The highest methane yield was observed for co-digestion of excess sludge from the AGS process and FW, which was 312 ± 8 mL CH4/g VS. Integration of FW as a co-substrate in the AGS process would potentially enhance energy recovery and the quality of effluent in municipal wastewater treatment.
  • Öge
    Implementation of 3D spatial planning through the integration of the standards
    (Wiley, 2024) Güler, Doğuş ; orcid.org/0000-0002-3191-103X ; Harita Mühendisliği
    To plan future land use, zoning plans (i.e., spatial plans) are prepared to get the most out of land for both the public and the government. These plans manifest which facilities can be built and where they can be built on land based on defined requirements such as building height and road length. The Land Administration Domain Model (LADM) is well-known and widely used standard for describing Rights, Restrictions, and Responsibilities (RRRs) with respect to land and buildings. The next version of the standard will contain the Spatial Plan Information (SPI) part to enable better land-use planning. Three-dimensional (3D) land-use planning has gained attention to delineate detailed requirements inclusively and allow different spatial analysis that provides a basis for decisions in the planning. Data standards pertaining to 3D geoinformation are vital to put into practice 3D spatial planning. To this extent, CityJSON is proposed for the effortless and efficient use of 3D city models. This article thus first aims to extend the CityJSON schema based on the proposed SPI part of the LADM such that it allows modeling, storing, visualizing, and utilizing the features and attributes required for the implementation of 3D spatial planning. Then, the usability of the proposed extension schema is demonstrated by the real-world use cases that benefit from the exemplary CityJSON files that are created based on approved zoning plans in the country. The results of this study show that there is an important opportunity coming from the integration of international standards that enables semantic information along with their spatial counterparts within 3D spatial planning.