Atılım Academic Archive
Atılım Academic Archive; It is a digital open archive created for the Atılım University research ecosystem, which includes peer-reviewed articles, technical reports, study reports, master's / doctoral theses and more.
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Techno-Economic assessment of PV, wind, and geothermal energy hybrid system for green hydrogen production: A case study in Denizli, Türkiye
(Elsevier Ltd, 2026) Devrim, Yılser; Nalbant Atak, Yagmur; Erdogan, Anil
This study presents a scenario-based techno-economic assessment of grid-connected green hydrogen production in Denizli, Türkiye using a hybrid renewable energy system integrating photovoltaic (PV), wind turbine (WT), and geothermal power plant (GP) with a proton exchange membrane electrolyzer (PEMEL). A demand-driven electrolyzer sizing approach is adopted, and four configurations (PV–WT–GP, PV–GP, WT–GP, and PV–WT) are evaluated under three hydrogen production levels (750, 1000, and 1500 kg/day), resulting in twelve scenarios. An energy balance model simulates operation and grid interaction, while techno-economic performance is evaluated via net LCOH. LCOH ranges from 8.8 to 18.8 €/kg H2, lowest for PV–WT–GP at low output. Higher capacity increases dependence on grid and costs, indicating diseconomies of scale. Sensitivity analysis shows electricity import/export prices strongly affect LCOH, especially at larger scales, highlighting the role of hybrid design and geothermal integration. © 2026 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
Structure–Property–Performance Relationship of Graphene Oxide Modified Composite Membranes for Anion Exchange Membrane Electrolyzers
(John Wiley and Sons Inc, 2026) Devrim, Yılser; Altinisik, Hasan; Abay, Ogün; Özalp, Ercan; Kim, Hern; Önel, Nisa Gökçen
In this study, graphene oxide (GO)-modified poly (phenylene oxide, PPO) anion exchange membranes (F/GO) were developed forapplication in anion exchange membrane electrolyzers (AEMELs). The incorporation of GO enhanced membrane hydration, ion-exchange capacity, and hydroxide-ion conductivity, resulting in an ~15% increase in current density at 2.0 V and 80°C (0.551 A/cm2) compared with the pristine membrane (0.480 A/cm−2). The F/GO membranes also showed enhanced hydrogen productionrates and an HHV-based energy efficiency of 76% at 0.5 A/cm2 and 80°C. These results underscore the potential for F/GO mem-branes in scalable AEMEL applications. Mechanical and alkaline stability tests confirmed robustness under harsh conditions.These findings demonstrate that the incorporation of GO provides a simple, scalable, and potentially lower-cost modificationstrategy compared with highly engineered polymer architectures, while also improving overall electrolyzer performance, high-lighting the potential of GO-modified membranes for practical hydrogen production in AEMEL systems.
Bayesian polarimetric multi-source direction-of-arrival estimation for transient astronomy with sparse radio interferometric subarrays
(Elsevier B.V., 2026) Tank, Fatih; Zeghdoudi, Halim
Modern radio interferometers are increasingly challenged by fast transient events, complex radio-frequency interference (RFI), and observing conditions in which near-field and far-field emitters may coexist. Although classical direction-of-arrival (DOA) techniques can achieve high angular resolution, they are often developed for specific array geometries, tend to focus on single-source settings, and usually provide little information about uncertainty. Imaging-based methods, while powerful, are computationally demanding and can introduce delays that are not well suited to real-time transient astronomy. In this work, we propose a Bayesian, polarization-aware framework for multi-source DOA estimation in arbitrary radio interferometric arrays. Starting from baseline-level covariance modeling and polarization-sensitive phase information, we build a probabilistic formulation that jointly infers source direction, polarization state, and, when relevant, source range. Because interferometric phase is inherently wrapped, uncertainty is modeled explicitly using circular statistical distributions, and posterior inference is carried out through a variational Bayesian scheme that remains computationally efficient. Compared with deterministic or purely data-driven approaches, the proposed method offers a more physically grounded and statistically interpretable alternative. It incorporates array geometry, polarization structure, and prior astronomical knowledge directly into the inference process, while also delivering calibrated uncertainty estimates for source localization. Simulations using realistic LOFAR and SKA-Low configurations show robust multi-source separation, stable performance across wide bandwidths, and improved resilience in low signal-to-noise and near-field conditions. Overall, the proposed framework enables imaging-free, uncertainty-aware localization of fast radio bursts, solar radio emission, and terrestrial RFI. It provides a statistically principled and computationally practical route toward real-time transient localization in next-generation radio observatories. © 2026 The Authors.
An Approach for Neighborhood Form Generation for Post-Disaster and Post-Conflict Temporary Housing Settlements
(Springer Nature, 2025) Akdede, Nil; Özer, Bekir; Dino, İpek Gürsel
Temporary housing settlements are one of the most significant post-crisis
responses following detrimental disasters and forced displacement. However, the urgency to provide immediate shelter often results in the use of conventional methods that overlook fundamental spatial design considerations. Recognizing the need for a new approach to settlement generation, this study introduces a novel method ology for neighborhood form generation in post-disaster and post-conflict tempo rary housing settlements during the preparedness period of disaster management. In this study, a three-step methodology is adopted. First, design codes for post disaster and post-conflict temporary housing settlements are thoroughly investigated through a comprehensive literature review. Then, the layout elements and basic spatial assumptions guiding the neighborhood form generation are identified. Finally, the requirements and constraints for neighborhood form generation in post-disaster and post-conflict temporary housing settlements are formulated, incorporating spatial design considerations. In contrast to the prevailing focus on housing design in various projects and approaches, the proposed approach, emphasizing spatial design considerations, holds promise for affected communities by enabling livable neigh borhoods and for humanitarian workers involved in the provision and design of PDPC settlements. This offers a new approach to enhance shelter response efforts.
İNTESTİNAL NEMATODLAR
(NOBEL TIP KİTABEVLERİ, 2025) Usluca, Selma; Demirel, Filiz
İntestinal nematodların tümünde (Ascaris lumbricoides, Tric huris trichura, Enterobius vermicularis, Strongyloides stercoralis ve kancalı kurtlar) kesin konak insandır ve ara konağa ihtiyaç duymadan yaşam döngülerini tamamlarlar (1). Enfeksiyon yumurtalarla kontamine su ve gıdaların ağız yoluyla alınması (A. lumbricoides ve T. trichiura) ve dışkıyla kirlenmiş toprak la temas sonucu enfektif larvaların deriden nüfuz etmesi yo luyla (kancalı kurtlar ve Strongyloides stercoralis) bulaşır (2). Toprakla bulaşan helmintler olarak gruplandırılan A. lumb ricoides, T. trichiura ve kancalı kurt (Ancylostoma duodenale ve Necator americanus) enfeksiyonları ihmal edilen 13 önemli tropikal hastalık arasında en yaygın olanlarıdır (3, 4). Dünya Sağlık Örgütü (DSÖ) bu hastalıkların endemik olduğu ülkelerde özellikle risk altındaki gruplar olarak kabul edilen üreme çağındaki kadınlar (gebeliğin ilk üç ayı hariç), okul öncesi ve okul çağındaki çocukların yanı sıra, diğer risk altındaki grupları da hedef alan toplu antihelmintik ilaç uygu laması yoluyla enfeksiyon yoğunluğunu ve yaygınlığını azal tarak morbiditeyi kontrol altına almayı amaçlamaktadır (5-7). Bu hastalıklar sıklıkla düşük ve orta gelirli ülkelerde yaygın olmasına rağmen, yüksek gelirli ülkelerde de hassas nüfuslar da görülebilmektedir (5, 8). Yetersiz besin alımı, paraziter has talıklara duyarlılığı artırabilmektedir. Düşük sosyo-ekonomik durum, düşük eğitim düzeyleri, kötü sağlık koşulları, yeterli temiz suya erişimin olmaması, yetersiz sanitasyon ve hijyen koşulları, su kaynaklarına yakın mesafede yaşamak ve mesle ki durumun (çi çilik ve balıkçılık) bu enfeksiyonlar açısından risk oluşturduğu bilinmektedir (3, 5). Gelişmekte olan ülkele rin çoğunda fizyolojik, zihinsel ve fiziksel gelişimin kritik dö nemi olan beş ila 15 yaş arasındaki okul çağı çocukları kronik helmint enfeksiyonu açısından en yüksek risk altındadır (9). Gebelikte humoral bağışıklık korunurken, hücresel bağışıklıkta zayıflama görülmekte, gestasyonel immünolojik değişiklikler nedeniyle paraziter enfeksiyonlara duyarlılık artmaktadır. Parazitler besin maddeleri için konakla rekabete girerek veya besinlerin emilimini engelleyerek besin maddelerinin eksikliğine yol açabilmektedir. Bu durum annenin nispeten daha düşük bir parazit yükünden daha fazla etkilenmesine neden olmaktadır. Bağırsak parazitleri beslenme durumunu farklı mekanizmalarla da etkileyebilmektedir. Bu enfeksiyonlar iş tahı ve dolayısıyla yiyecek alımını azaltmakta, besin emilimini engelleyen bağırsak iltihabına, bağırsak mukozasına zarar vererek malabsorbsiyona ve ishale neden olmaktadır. Kancalı kurtlar ayrıca bağırsakta kan kaybına yol açar (10). Bu enfeksiyonlar okul çağındaki çocuklarda büyüme geriliği, entelektüel ve bilişsel fonksiyonlarda bozukluğa neden olabilir (3, 6, 9, 11, 12). A. lumbricoides ve T. trichiura enfeksiyonları özellikle okul çağındaki çocuklarda en yüksek oranda saptanırken, kancalı kurt enfeksiyonları ergenlik ve genç erişkinlik döneminde daha fazla görülür (12).