Araştırma Çıktıları | TR-Dizin | WoS | Scopus | PubMed

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Citation - WoS: 6
Citation - Scopus: 6
3-Sulfopropyl Methacrylate Based Cryogels as Potential Tissue Engineering Scaffolds
(Taylor & Francis Ltd, 2020) Durukan, Adile Yuruk; Isoglu, Ismail Alper; 01. Abdullah Gül University; 04. Yaşam ve Doğa Bilimleri Fakültesi; 04.01. Biyomühendislik
In this study, we developed cryogels containing 3-sulfopropyl methacrylate (SPMA) and 4-vinyl pyridine (4-VP) as a potential scaffold for tissue engineering applications. Cryogels with varying monomer ratios were synthesised by chemical cross-linking under cryogelation conditions. Effect of initiators and cross-linker amount (0.025-0.15 g MBA; 0.012-0.05 g APS; 2.5-12.5 mu l TEMED) and also freezing temperature (-20 and -80oC) were investigated, and the conditions were optimised according to the morphological structures examined by SEM. The functional groups of the materials were characterised by FT-IR. Compression test and swelling were applied to investigate mechanical properties and water absorption ability, respectively. As a preliminary study, selected materials were tested for cell cytotoxicity with MTT. According to our results, the ionic and biocompatible cryogels prepared in this study possessing a highly porous and interconnective structure with good mechanical characteristics and swelling properties can be suitable as tissue scaffolds for many applications.
Citation - Scopus: 3
50 Years of Resources Policy – What Is Next? Key Areas of Future Research
(Elsevier Ltd, 2024) Fleming-Munoz, David A.; Campbell, Gary A.; Ley, Yalin; Arratia-Solar, Andrea; Aroca, Patricio A.; Atienza-Ubeda, Miguel; Kumral, Mustafa; 01. Abdullah Gül University
In 2024, Resources Policy reaches its 50th anniversary as a journal. Fifty years leading the field of mineral and fossil fuel policies and economic research worldwide. Considering this special milestone, we provide a forward-looking view in this paper, highlighting seven areas we believe are critical for robust research that Resources Policy should publish in the future. Leveraging our research expertise and knowledge with the journal, these seven areas of future research include implications of post-mining and energy transitions, the dark side of critical minerals, the increasing substitution of local labour by alternative inputs, the role of the resource curse in resilience considerations, the cleaner production role of mining, macroeconomic frameworks, and the future of mining beyond mines (deep-sea and space mining). We believe more research is needed in these seven research areas, which can enhance our understanding of critical aspects, reduce uncertainty, and provide novel ways to address societal, environmental, economic and policy challenges related to the extraction and use of minerals and fossil fuels. © 2024 Elsevier B.V., All rights reserved.
Citation - WoS: 2
Citation - Scopus: 1
94.8 Km-Range Direct Detection Fiber Optic Distributed Acoustic Sensor
(Optica Publishing Group (Formerly OSA), 2019) Uyar, F.; Onat, T.; Unal, C.; Kartaloǧlu, T.; Ozdur, I.; Özbay, E.; 01. Abdullah Gül University
This work demonstrates an ultra-long range direct detection fiber optic distributed acoustic sensor which can detect vibrations at a distance of 94.8 km with 10 m resolution along the sensing fiber. © 2023 Elsevier B.V., All rights reserved.
Citation - WoS: 2
Citation - Scopus: 3
94.8 Km-Range Direct Detection Fiber Optic Distributed Acoustic Sensor
(Institute of Electrical and Electronics Engineers Inc., 2019) Uyar, Faruk; Onat, Talha; Unal, Canberk; Kartaloǧlu, Tolga; Ozdur, Ibrahim T.; Özbay, Ekmel; 01. Abdullah Gül University
This work demonstrates an ultra-long range direct detection fiber optic distributed acoustic sensor which can detect vibrations at a distance of 94.8 km with 10 m resolution along the sensing fiber. © 2019 Elsevier B.V., All rights reserved.
A Comparative Study of Existing and Current On-Site Documentation of Anatolian Seljuk Kümbets
(Elsevier Ltd, 2025) Güzelci, O.Z.; Türel, A.; 01. Abdullah Gül University
During the Anatolian Seljuk period (1077–1307), monumental tombs known as kümbets emerged as a distinct architectural typology in present-day Türkiye. 2D drawings of these structures, produced since the early 20th century, contain inconsistencies that necessitate verification and accurate documentation. This study digitally documents Anatolian Seljuk kümbets in 3D to generate updated 2D sections reflecting their current condition and compares these with previously published drawings. The methodology includes collecting available 2D sections, digitally documenting kümbets through field studies, generating new 2D sections from 3D models, and systematically comparing these datasets. Two image-based metrics are employed in the comparison: the Exact Pixel Match Ratio (EPMR), which evaluates pixel-level alignment, and the Structural Similarity Index Measure (SSIM), a standard indicator for visual similarity. The results provide a comparative framework for assessing previous drawings and present a verified, up-to-date dataset of kümbet sections for future research. © 2025 Elsevier B.V., All rights reserved.
A Comprehensive Review on the Extraction and Recovery of Lithium from Primary and Secondary Sources: Advances Toward Battery-Grade Materials
(Wiley, 2025) Top, Soner; Kursunoglu, Sait; Altiner, Mahmut; 01. Abdullah Gül University; 02.07. Malzeme Bilimi ve Nanoteknoloji Mühendisliği; 02. Mühendislik Fakültesi
Lithium-ion battery (LIB) technologies have become indispensable to modern energy systems, driving global demand for high-purity lithium compounds. This review focuses on lithium recovery and purification strategies for battery-grade lithium carbonate (Li2CO3) and lithium hydroxide (LiOH), addressing both primary sources (brines and minerals) and secondary sources (waste materials). Industrially established processes, such as evaporation-based brine treatment and conventional metallurgical methods, are discussed alongside emerging techniques, including membrane separation, solvent extraction, and CO2-assisted precipitation. Particular attention is given to lithium precipitation mechanisms, the behaviour of co-existing ions during extraction, and the specific quality requirements for cathode material synthesis. By evaluating process scalability, environmental impact, and product purity, this review provides a comprehensive understanding of current practices and future directions. Additionally, it highlights the growing importance of lithium in the context of accelerating electric vehicle (EV) adoption, underscoring the bright and expanding future of the lithium industry.
Citation - WoS: 3
Citation - Scopus: 3
Ab Initio Simulation of Amorphous BC3
(Elsevier, 2020) Durandurdu, Murat; 01. Abdullah Gül University; 02.07. Malzeme Bilimi ve Nanoteknoloji Mühendisliği; 02. Mühendislik Fakültesi
We report the structural and electrical properties of an amorphous BC3 model based on ab initio molecular dynamics simulations. The amorphous network is achieved from the melt and has a layer-like structure consisting of mainly hexagonal (six membered) rings as in the crystal. However, the distribution of boron atoms in the noncrystalline configuration appears to differ significantly from that of boron atoms in the crystal. The network is a solid solution and has randomly distributed nanosized graphene-like domains at each layer. Boron atoms have a tendency to form more overcoordinated defects involving with boron-boron homopolar bond(s). The mean coordination of boron and carbon atoms is 3.2 and 3.0, respectively. Interestingly the amorphous configuration is found to have a slightly higher density and bulk modulus than the crystal, which are attributed to the existence of overcoordinated units in the amorphous state. Based on the localization of the band tail states, noncrystalline BC3 is speculated to be a semiconducting material.
Citation - WoS: 1
Citation - Scopus: 1
Ab Initio Study of Boron-Rich Amorphous Boron Carbides
(Wiley, 2023) Yildiz, Tevhide Ayca; Durandurdu, Murat; 01. Abdullah Gül University; 02.07. Malzeme Bilimi ve Nanoteknoloji Mühendisliği; 02. Mühendislik Fakültesi
Amorphous boron carbide compositions having high B contents (BxC1-x, 0.50 <= x <= 0.95) are systematically created by way of ab initio molecular dynamics calculations, and their structural, electrical, and mechanical characteristics are inclusively investigated. The coordination number of both B and C atoms increases progressively with increasing B/C ratio and more close-packed materials having pentagonal pyramid motifs form. An amorphous diamond-like local arrangement is found to be dominant up to 65% B content, and beyond this content, a mixed state of amorphous diamond- and B-like structures is perceived in the models because sp(3) hybridization around C atoms is still leading one for all compositions. The pentagonal pyramid motifs around C atoms are anticipated to appear beyond 65% content. The intericosahedral linear C-B-C chains do not form in any model. All amorphous boron carbides are semiconducting materials. The mechanical properties gradually increase with increasing B concentration, and some amorphous compositions are proposed to be hard materials on the basis of their Vickers hardness estimation.
Absolute Phase Noise Analysis of a Harmonically Modelocked Semiconductor Laser
(Optica Publishing Group (formerly OSA), 2017) Özharar, Sarper; Ozdur, Ibrahim T.; 01. Abdullah Gül University
We have designed and built a fiber coupled semiconductor laser at 1550 nm, which is harmonically mode-locked at 10 GHz by an external RF oscillator. The absolute phase noise of the laser is measured and discussed for two different cavity lengths. © 2023 Elsevier B.V., All rights reserved.
Citation - WoS: 6
Citation - Scopus: 6
Absorption Enhancement by Semi-Cylindrical Structures for an Organic Solar Cell Application
(Optical Soc Amer, 2020) Hah, Dooyoung; 01. Abdullah Gül University; 02. Mühendislik Fakültesi; 02.05. Elektrik & Elektronik Mühendisliği
Organic solar cells are attractive for various applications with their flexibility and low-cost manufacturability. In order to increase their attractiveness in practice, it is essential to improve their energy conversion efficiency. In this work, semi-cylindrical-shell-shaped structures are proposed as one of the approaches, aiming at absorption enhancement in an organic solar cell. Poly(3-hexylthiophene-2,5-diyl) blended with indene-C60 bisadduct (P3HT:ICBA) is considered as the active layer. Light coupling to the guided modes and a geometrical advantage are attributed to this absorption enhancement. Finite-difference time-domain methods and finite element analysis are used to examine the absorption spectra for two types of devices, i.e., a debossed type and an embossed type. It is shown that absorption enhancement increases as the radius of the cylinder increases, but reaches a saturation at about 4-mu m radius. The average absorption enhancement with an active layer thickness of 200 nm and radius of 4 mu m, and for incidence angles between 0 degrees and 70 degrees, is found as 51%-52% for TE-polarized input and as 30%-33% for TM-polarized input when compared to a flat structure. Another merit of the proposed structures is that the range of incidence angles where the integrated absorption is at the level of the normal incidence is significantly broadened, reaching 70 degrees-80 degrees. This feature can be highly useful especially when organic solar cells are to be placed around a round object. The study results also exhibit that the proposed devices bear broadband absorption characteristics. (C) 2020 Optical Society of America
Acoustic Transformation of Rock-Cut Caves Into Performance Spaces
(European Acoustics Association, EAA, 2023) Aslan, Ahmet; Şaher, Konca; Tozoğlu, Ahmet Erdem; 01. Abdullah Gül University; 05.01. Mimarlık; 05. Mimarlık Fakültesi
Cappadocia Region in Turkey is a center of attention as a tourism destination with its rock-cut caves, some of which are being used as performance spaces for concerts, festivals and local entertainment activities. However, these spaces are not fully investigated for their acoustic performance before being transformed into performance venues. This paper reports on the findings of an initial survey which presents a systematic mapping of the rock-cut caves used as performance spaces to locate, explore and document a sample of structures scattered in this historic district. A typological classification based on volume, size, type of tuff rock material and historical original use has been proposed and an acoustic analysis of some selected rock-cut caves has been carried out. The acoustic analysis included reverberation time calculations and simulations based on apparent volume, and tuff stone absorption characteristics, which were studied by other researchers in the area. © 2024 Elsevier B.V., All rights reserved.
Citation - Scopus: 49
Activation of Methane by Os+: Guided-Ion and Theoretical Studies
(2013) Armentrout, Peter B.; Parke, Laura G.; Hinton, Christopher S.; Citir, Murat; 01. Abdullah Gül University
Activation of methane by the third-row transition-metal cation Os + is studied experimentally by examining the kinetic energy dependence of reactions of Os+ with CH4 and CD4 using guided-ion-beam tandem mass spectrometry. A flow tube ion source produces Os+ in its electronic ground state and primarily in the ground spin-orbit level. Dehydrogenation to form [Os,C,2 H]++H2 is exothermic, efficient, and the only process observed at low energies for reaction of Os+ with methane, whereas OsH+ dominates the product spectrum at higher energies. The kinetic energy dependences of the cross sections for several endothermic reactions are analyzed to give 0K bond dissociation energies (in eV) of D0(Os+-C)=6.20±0. 21, D0(Os+-CH)=6.77±0.15, and D0(Os +-CH3)=3.00±0.17. Because it is formed exothermically, D0(Os+-CH2) must be greater than 4.71eV, and a speculative interpretation suggests the exothermicity exceeds 0.6eV. Quantum chemical calculations at the B3LYP/def2-TZVPP level show reasonable agreement with the experimental bond energies and with previous theoretical values available. Theory also provides the electronic structures of the product species as well as intermediates and transition states along the reactive potential energy surfaces. Notably, the structure of the dehydrogenation product is predicted to be HOsCH+, rather than OsCH2+, in contrast to previous work. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. © 2013 Elsevier B.V., All rights reserved.
Active Control of the Nanoparticle Self-Assembly for Photonic Applications
(META Conference, 2023) Erdem, Talha; 01. Abdullah Gül University; 02. Mühendislik Fakültesi; 02.05. Elektrik & Elektronik Mühendisliği
Colloidal nanoparticles enable collective utilization of the inherent properties of the nanoparticles. Furthermore, their collective optical response can be fine-tuned employing DNA-driven self-assembly. Here, we present that the optical transmission of self-assembled DNA-functionalized gold nanoparticle network can be actively manipulated using an external optical excitation. We also show control of optical polarization of emitted light from semiconducting supraparticle networks hybridized with magnetic supraparticles. These results prove the potential of programmed nanoparticle self-assembly in tailoring optical features of colloidal systems. © 2023 Elsevier B.V., All rights reserved.
Citation - WoS: 5
Citation - Scopus: 4
Active Subnetwork Ga: A Two Stage Genetic Algorithm Approach to Active Subnetwork Search
(Bentham Science Publ Ltd, 2017) Ozisik, Ozan; Bakir-Gungor, Burcu; Diri, Banu; Sezerman, Osman Ugur; 01. Abdullah Gül University; 02. 04. Bilgisayar Mühendisliği; 02. Mühendislik Fakültesi
Background: A group of interconnected genes in a protein-protein interaction network that contains most of the disease associated genes is called an active subnetwork. Active subnetwork search is an NP-hard problem. In the last decade, simulated annealing, greedy search, color coding, genetic algorithm, and mathematical programming based methods are proposed for this problem. Method: In this study, we employed a novel genetic algorithm method for active subnetwork search problem. We used active node list chromosome representation, branch swapping crossover operator, multicombination of branches in crossover, mutation on duplicate individuals, pruning, and two stage genetic algorithm approach. The proposed method is tested on simulated datasets and Wellcome Trust Case Control Consortium rheumatoid arthritis genome-wide association study dataset. Our results are compared with the results of a simple genetic algorithm implementation and the results of the simulated annealing method that is proposed by Ideker et al. in their seminal paper. Results and Conclusion: The comparative study demonstrates that our genetic algorithm approach outperforms the simple genetic algorithm implementation in all datasets and simulated annealing in all but one datasets in terms of obtained scores, although our method is slower. Functional enrichment results show that the presented approach can successfully extract high scoring subnetworks in simulated datasets and identify significant rheumatoid arthritis associated subnetworks in the real dataset. This method can be easily used on the datasets of other complex diseases to detect disease-related active subnetworks. Our implementation is freely available at https://www.ce.yildiz.edu.tr/personal/ozanoz/file/6611/ActSubGA.
Adaptive Re-Use of Medieval Caravanserais in Central Anatolia
(Gangemi Editore S P A, 2019) Yoney, Nilufer Baturayolu; Asiliskender, Burak; Urfalioglu, Nur; 01. Abdullah Gül University; 05.01. Mimarlık; 05. Mimarlık Fakültesi
Kayseri, located at the junction of two major trade routes from northeast to southwest and from southeast to northwest, has been a commercial center for at least 4,000 years. The 23,500 tablets found at the Assyrian trade colony in Kanesh-Karum dating around 2,000 BCE and located 20km from the modern city provide ample proof. The great number and relevant size of Medieval caravanserais around the city as well as commercial buildings at the center indicate that this importance continued. Some of these caravanserais are already in use, albeit with inadequate architectural preservation measures while others are abandoned and/or partially destroyed. Indeed, the preservation, restoration and adaptive re-use of Medieval buildings is a major problematic, bringing out issues and interventions related to lacunae and reintegration, liberation or clearance of additions, structural strengthening with traditional/contemporary technologies, partial reconstruction, consolidation, cleaning and conservation of original building materials, and preventive maintenance. This paper aims to consider the possible presentation and adaptive re-use of Seljukid caravanserais over and inventory of accessible and at least partially preserved examples, focusing on eight case studies from the late 12th and 13th centuries: Karatay Han (1240), Tuzhisar Sultan Han (1232-1236), Eshab-i Kehf Han (before 1235), Cirgalan Han, Saruhan, Agzikarahan (1231-1240), Alayhan and Oresin Han.
Citation - Scopus: 2
Adaptive Reuse of Industrial Heritage: Resilience or Irreparable Loss
(Docomomo, 2016) Baturayoğlu Yöney, Nilüfer; Asiliskender, Burak; Özer, Aysegul; 01. Abdullah Gül University; 05.01. Mimarlık; 05. Mimarlık Fakültesi
The restoration and adaptive reuse of industrial heritage buildings and complexes, which present structurally and functionally resilient shells, provide us with an interesting dilemma in theory and practice: made of hard wearing materials to house straining functions and to last as long as possible, they are also flexible enough to adapt to almost any new purpose as a container. However, the presence of original machinery and equipment as well as designs based on machine-buildings may reduce the possibilities of adaptive reuse to a museum, where the buildings exhibit themselves, retaining the social, economic, historic and public aspects of cultural heritage as documents. Although originally built on the outskirts of urban settlements, today most industrial heritage complexes occupy central locations in the metropolitan sprawl of major cities. If disused, they are considered obsolete brownfields by local authorities and citizens despite personal and collective memories that may be attached to them. Their conversion into new uses presents major technical difficulties that require expertise in design and implementation. This paper discusses the theoretical and practical aspects of the adaptive reuse of industrial heritage and inherent problems, focusing on the case of the Sümerbank Kayseri Textile Factory (I. Nikolaev, Turkstroj, 1932-1935), which is being transformed into the campus of Abdullah GUI University. The restoration, renovation and adaptive reuse projects for different components of the complex follow similar principles of preservation and sustainability while they are modified to fit the architectural and technological characteristics of each building. Thus, although conversive and easily adaptable, the preservation of industrial architectural heritage becomes a dilemma between disruption and continuity, which the architects have to solve going beyond the possibilities of mere building stock on the one hand and that of the museum on the other. © 2017 Elsevier B.V., All rights reserved.
Citation - WoS: 1
Citation - Scopus: 1
Addressing the Modern Regimes of Urban Spectacle: Revisiting the Ottoman General Exhibition of 1863 in Istanbul
(Sage Publications inc, 2024) Tozoglu, Ahmet Erdem; 01. Abdullah Gül University
One of the most spectacular events of the Ottoman experience of modernity was the inauguration of the Ottoman General Exposition in Istanbul in 1863. The ancient Hippodrome, which is one of the most prominent venues of the city and the setting of memorable celebrations and festivals for centuries, hosted the event and provided the visitors with the opportunity to become part of the modern regimes of gaze and spectacle. This article posits three observer roles to reveal the multilayered structure of urban spectacle in mid-century Istanbul, namely the sultanic gaze, spectacle of the ordinary citizens, and the mediated experience of the foreigner. To understand the particularities of each position, I utilize several visual and textual documents about the exhibition event. Though just a single case in Ottoman urban history, the exposition enables us to understand how the new manner of modern urban spectacle emerged during a spectacular public event in Istanbul.
Citation - WoS: 5
Citation - Scopus: 5
Admissible Invariants of Genus 3 Curves
(Springer Heidelberg, 2015) Cinkir, Zubeyir; 01. Abdullah Gül University; 02.02. Endüstri Mühendisliği; 02. Mühendislik Fakültesi
Several invariants of polarized metrized graphs and their applications in Arithmetic Geometry are studied recently. In this paper, we explicitly calculated these admissible invariants for all curves of genus 3. We find the sharp lower bound for the invariants phi, lambda and epsilon for all polarized metrized graphs of genus 3. This improves the lower bound given for Effective Bogomolov Conjecture for such curves.
Adult Zebrafish Brain as a Demyelination Model and Role of WNF Signaling in Remyelination
(Wiley, 2024) Bora, U.; Demirbasoglu, E. S.; Turhanlar-Sahin, E.; Guner, H.; Ozhan, G.; 01. Abdullah Gül University; 04. Yaşam ve Doğa Bilimleri Fakültesi; 04.02. Moleküler Biyoloji ve Genetik
Citation - WoS: 3
Citation - Scopus: 4
Advanced Hybrid Machine Learning Methods for Predicting Rainfall Time Series: The Situation at the Kütahya Station in Türkiye
(Springer Heidelberg, 2025) Ilkentapar, Mucella; Citakoglu, Hatice; Talebi, Hamed; Akturk, Gaye; Spor, Pinar; Caglar, Yasin; Aksit, Serhat; 01. Abdullah Gül University; 02.03. İnşaat Mühendisliği; 02. Mühendislik Fakültesi
Long-term variations in rainfall patterns, known as rainfall variability, have increasingly impacted ecological and socioeconomic systems, particularly in regions with high sensitivity. Consequently, accurate forecasting of rainfall at both short- and long-term time scales is essential, necessitating a comprehensive analysis of historical rainfall time series data collected from meteorological stations. In this study, K & uuml;tahya Province was selected as the study area, utilizing monthly rainfall data from its sole meteorological station spanning the period from 1960 to 2023. The dataset was partitioned into a training set (January 1960-March 2008) and a test set (April 2008-December 2023). Lagged rainfall values at t-1, t-2, and t-3 were used as input variables to predict rainfall at time t. The primary objective of this research is to assess the effectiveness of various preprocessing techniques in developing hybrid machine learning models for rainfall prediction. Gaussian Process Regression (GPR), Support Vector Machines, and Adaptive Neuro-Fuzzy Inference System were employed as machine learning methods. Furthermore, multiple signal decomposition techniques, including Complete Ensemble Empirical Mode Decomposition (CEEMD), Tunable Q-Factor Wavelet Transform, Empirical Mode Decomposition, Robust Empirical Mode Decomposition, Variational Mode Decomposition, Empirical Wavelet Transform, and Ensemble Empirical Mode Decomposition (EEMD), were utilized as preprocessing steps to enhance model performance. The predictive performance of the developed hybrid models was evaluated using various statistical measures. Among the evaluated models, the CEEMD-GPR hybrid model exhibited the best prediction performance with Coefficient of Determination (R2 = 0.998) and Nash-Sutcliffe Efficiency (NSE = 0.998) values close to 1, Mean Absolute Error (MAE = 1.42) and Mean Squared Error (RMSE = 1.79) values close to zero. These findings indicate that CEEMD demonstrated superior decomposition efficiency compared to the other six decomposition techniques. Additionally, the Kruskal-Wallis test conducted during the analysis phase yielded a statistical significance level of p > 0.05, confirming that the observed and predicted rainfall data originated from the same distribution. Consequently, the effectiveness and reliability of the proposed hybrid models for rainfall prediction were validated.

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