TR-Dizin
Permanent URI for this collectionhttps://hdl.handle.net/20.500.14411/21
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Article Isometric Representations of Calibrated Ordered Spaces on C(X)(Ankara University, Fac Sci, 2025) Ay, Serdar; Serdar, A. Y.The problem of characterizing normed ordered spaces which admit a representation in the algebraic, order and norm sense as a subspace of $C(X)$, the space of all continuous functions on a compact Hausdorff space is a classical problem that has been considered by many authors. In this article we consider the more general case of calibrated ordered spaces, that is, ordered spaces with a specified family of seminorms generating its topology. For such spaces equivalent conditions on representability as a subspace of $C(X)$ for some locally compact Hausdorff space $X$, in the algebraic, order and seminorm sense are stated and proved. Some characterizations appear to be new even in the normed case. A recent result on isometric representations of locally ordered spaces fall under the results in this paper with more general statements. As an application of the main theorems, we state and prove a characterization of norm additivity property of two positive functionals.Article Influence of Synthesis Parameters on the Structural Formation of Mayenite via the Citrate Sol-Gel Method(Tubitak Scientific & Technological Research Council Turkey, 2025) Eryildirim, Busra; Oktar, Nuray; Dogu, DorukMayenite (Ca12Al14O33) has remarkable properties such as high oxygen mobility, ionic conductivity, and catalytic activity. It has many different applications, including oxide-conducting electrolytes, fluorescent lamps, moisture sensors, hydrogen-permeable membranes, oxygen pumps, hydrogen storage, and catalysis. However, pure and homogeneous mayenite synthesis parameters have not yet been fully explored. This study examines the effect of synthesis parameters including metal salt (MS) to citric acid (CA) molar ratios (1:1 and 1:2), pH (0.4-2), and calcination temperature (900-1200 degrees C) in citrate sol-gel method on the crystal structure of mayenite. Synthesized materials were examined by thermogravimetric (TG), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, N2 adsorption-desorption, scanning electron microscopy (SEM), inductively coupled plasma-optical emission spectrometry (ICP-OES), Fourier-transform infrared spectroscopy (FTIR), and pyridine adsorbed diffuse reflectance Fourier-transformed infrared spectroscopy (DRIFTS) analyses. The results show that all 3 parameters contribute to the mayenite phase formation and different impurity phases can be observed depending on the synthesis parameters. With no pH adjustment and an MS to CA ratio of 1, other phases of calcium aluminate mostly form. Mayenite becomes the main phase by doubling the CA amount. Besides CA, pH is also an important factor in mayenite synthesis. When the pH was adjusted to 2 with the MS to CA ratio at 1:1, mayenite was formed as the main phase, but other phases of calcium aluminate were also observed in the structure. XRD results show that all parameters studied influence the crystal structure of the final material, including the calcination temperature. This study shows that pure mayenite can be synthesized with a calcination temperature of 1200 degrees C, at a pH of 2, and the MS to CA molar ratio of 1:2.Article W-Band RCS Prediction of Small Objects: Comparing Two Widely Used Methods with Experimental Validation(Gazi University, 2025) Kara, Ali; Aydın, Elif; Yardım, Funda Ergün; Sezgin, Deniz; Ergun Yardim, FundaThis paper compares the accuracy of Shooting and Bouncing Rays and Electric Field Integral Equation methods for Radar Cross Section prediction of small objects at 77-81 GHz band. Existing studies on RCS prediction methods often lack comprehensive comparisons between computational and experimental results, particularly for small objects measured with a 77 GHz radar. This study addresses this gap by presenting an in-depth analysis of both simulation and measurement data. In this work, three targets with varying geometries and materials were measured with a frequency modulated continuous wave radar and simulated using Ansys HFSS and CST Studio Suite. The measurements were performed with a commercial off-the-shelf (COTS) frequency modulated continuous wave radar operating at 77–81 GHz. This study aims to emphasize the importance of considering both efficiency and accuracy when opting for an RCS prediction method. Overall, the outcomes of both methods have largely demonstrated good alignment. It has been noted that, while Shooting and Bouncing Rays method offers promising time-saving advantages, Electric Field Integral Equation method remains a valuable tool for complex geometries where precise results are crucial.Article ISAR Imaging of Drone Swarms at 77 GHz(Tubitak Scientific & Technological Research Council Turkey, 2025) Coruk, Remziye Busra; Kara, Ali; Aydin, ElifThe proliferation of easily available, internet-purchased drones, coupled with the emergence of coordinated drone swarms, poses a significant security threat for airspace. Detecting these swarms is crucial to prevent potential accidents, criminal misuse, and airspace disruptions. This paper proposes a novel inverse synthetic aperture radar (ISAR) imaging technique for high-resolution reconstruction of drone swarms at 77 GHz millimeter wave (mmWave) frequency, offering a valuable tool for military and defense antidrone systems. The key parameters affecting down-range and cross-range resolution (0.05 m), ultimately enabling the generation of detailed ISAR images are discussed. Here, we create diverse scenarios encompassing various swarm formations, sizes, and payload configurations by employing ANSYS simulations. To enhance image quality, different window functions are evaluated, and the Hamming window is selected due to its highest peak signal-to-noise ratio (PSNR) (16.3645) and structural similarity (SSIM) (0.9067) values, ensuring superior noise reduction and structural preservation. The results demonstrate that the effectiveness of high-resolution ISAR imaging in accurately detecting and characterizing drone swarms pave the way for enhanced airspace security measures.Article Citation - WoS: 3Citation - Scopus: 1Caval Valve Implantation Procedure in 7 Cases of Torrential Tricuspid Regurgitation and Step-By Description of the Procedure(Kare Publ, 2025) Sarıçam, Ersin; Barcin, Cem; Çelebi, Aksüyek Savaş; Asfour, Mohamed; Bozbas, Huseyin; İlkay, Erdoğan; Cam, Ersin; Celebi, Savas A.Tricuspid regurgitation (TR) is an increasingly prevalent and clinically significant health problem.1 Due to the growing understanding of the importance of TR, the tricuspid valve has transitioned from being a forgotten valve to one of significant concern. Tricuspid regurgitation is often functional, and as it progresses to moderate or severe stages, hospital admissions increase and prognosis worsens.1,2 There are no effective pharmacological treatments for TR, and the 5-year survival rate with medical management is reported to be less than 50%.3 Therefore, early diagnosis and timely intervention for TR is crucial. Both surgical and percutaneous treatment options are available for severe TR. The mortality rate for isolated TR surgery is generally high.4 In recent years, transcatheter treatments have become feasible for this patient group, and accumulating evidence shows that transcatheter treatment is superior to medical management.5,6 Transcatheter interventions for TR can be performed in 4 ways, 2 involving repair and 2 involving valve We aimed to present our experience with transcatheter caval valve implantation (CAVI) in 7 patients with torrential TR who were not suitable for surgical intervention or transcatheter edge-to-edge repair (T-TEER) due to severe coaptation defects, review the current literature, and provide a step-by-step description of the procedure.Article An Application of Stochastic Maximum Principle for a Constrained System With Memory(Ankara Univ, Fac Sci, 2025) Savku, EmelIn this research article, we study a stochastic control problem in a theoretical frame to solve a constrained task under memory impact. The nature of memory is modeled by Stochastic Differential Delay Equations and our state process evolves according to a jump-diffusion process with time-delay. We work on two specific types of constraints, which are described in the stochastic control problem as running gain components. We develop two theorems for corresponding deterministic and stochastic Lagrange multipliers. Furthermore, these theorems are applicable to a wide range of continuous-time stochastic optimal control problems in a diversified scientific area such as Operations Research, Biology, Computer Science, Engineering and Finance. Here, in this work, we apply our results to a financial application to investigate the optimal consumption process of a company via its wealth process with historical performance. We utilize the stochastic maximum principle, which is one of the main methods of continuous-time Stochastic Optimal Control theory. Moreover, we compute a real-valued Lagrange multiplier and clarify the relation between this value and the specified constraint.Article Citation - WoS: 1From Partners To Rivals: Normative Power Europe Meets Normative Power China(International Relations Council of Turkey, 2025) Sahin, Gözde Yilmaz; Yilmaz, GoezdeThe European Union (EU) has been promoting its norms, values, and rules for decades. However, in the current international environment, the EU’s normative power is not being received well outside the EU, particularly in reference to the growing power of illiberal states. Within that context, this study explores EU-China relations across time and unpacks the position of normative power Europe towards China and the Chinese response. The study foregrounds the fruitless attempts of the EU to project its transformative power onto China and the growing resistance by China against this, which it expresses by presenting itself to the West as an alternative power with an alternative understanding of international politics.Article Citation - WoS: 1Citation - Scopus: 2Cannabinoid Receptor Ligands Modulate Fibrosis and Inflammation in Idiopathic Pulmonary Fibrosis: a Preliminary Study(Tubitak Scientific & Technological Research Council Turkey, 2024) Kose, Sevil; Onen, Selin; Gizer, Merve; Boduroglu, Esin; Gonullu, Ugur; Korkusuz, PetekBackground/aim: No specific pharmacological treatment regimen for idiopathic pulmonary fibrosis (IPF) exists. Therefore, new antiinflammatory therapeutic strategies are needed. Cannabinoids (CBs), known for their inflammation-modulating and antifibrotic effects, may be potential medication candidates for treating IPF. We aim to evaluate the inflammation-modulating and antifibrotic effects of CB receptor (CBR) agonists and antagonists in lipopolysaccharide-stimulated normal human lung fibroblast, epithelial cells, IPF fibroblast cells, and monocytes. Materials and methods: We detected CBRs in normal human lung fibroblasts (LL24) and IPF fibroblast cells (LL29), epithelial cells (A549) and monocytes (THP-1) by flow cytometry. We determined TGF-(31, IL-8, and TNF-alpha inflammatory cytokines in the LL24, LL29, A549, and THP-1 cell culture supernatants on days 1 and 5 by ELISA. We evaluated the cell viability in LL24, LL29, and A549 cells on days 1, 3, and 5 spectrophotometrically and detected collagen Type I (ColI) production in the LL24 and LL29 cell culture supernatants on days 1, 3, and 5 by ELISA. Results: LL24, LL29, A549, and THP-1 cells exhibited CB1 (CB1R) and CB2 (CB2R) receptors. CB1R and CB2R agonists WIN55,2122 and JWH015 inhibited fibroblastic and epithelial cell proliferation on day 5. TGF-(31 and TNF-alpha release increased, while IL-8 release decreased in LL24, LL29, A549, and THP-1 cells in response to the administration of WIN55,212-2 and JWH015 at a 10-2 mM concentration. CB1R and CB2R antagonists AM251 and AM630 did not block agonistic responses, suggesting a nonclassical CBRmediated pathway. CB2R agonist JWH015 decreased ColI expression in IPF lung fibroblasts LL29 on day 3. Conclusion: These results suggest that CB signaling regulates the progression of pulmonary inflammation and fibrosis via CBR activation. This may offer a potential pharmacological tool for developing antifibrosis therapies.Article Makroekonomik ve Sosyo-politik Endeks Nitelikli Çalışan Başına Reel Gsyh’yi Nasıl Etkiler? Türk Cumhuriyetleri’nden Kanıtlar(2023) Çelik, Eşref Uğur; Erdal, Fehmi Buğra; Küçüker, Mustafa Can; Omay, TolgaBu çalışmada, nitelikli çalışan başına reel GSYH düzeyini etkileyen sosyoe- konomik faktörler üzerinde durulmuştur. Bu amaçla Türk Cumhuriyetleri için makroekonomik ve sosyo-politik performans endeksleri oluşturulmuştur. Yeni oluşturulan bu endeksler kullanılarak, nitelikli çalışan başına düşen reel GSYH düzeyinin belirleyicileri literatürde ilk kez analiz edilmektedir. Ampi- rik sonuçlar, belirli eşik düzeylerinin nitelikli çalışan başına reel GSYH düze- yini önemli ölçüde etkilediğini göstermektedir. Sonuç olarak, çalışmada yer verilen ülkelerin politika yapıcıları, ülkelerinin refahı açısından iyi organize edilmiş politikalar yürütmek için makroekonomik ve sosyo-politik perfor- mans endekslerin eşik değerlerini ciddi şekilde göz önünde bulundurmalıdır.Article Millî Mücadele Dönemi’nde Yunan Ordusu’nun Bursa'yı İşgali(2023) Birlik, Gültekin K.İstanbul’un 16 Mart 1920’deki resmî işgalinin amaçlarından biri de, millî kuvvetleri İstanbul’dan uzak tutmak olmuştur. Bununla birlikte, millî kuvvetler 4 Temmuz’da İstanbul Beykoz’da İngilizlere karşı saldırı gerçekleştirmiştir. Beykoz saldırısını büyük bir tehdit olarak algılayan İngilizler, İstanbul’u ve Boğazları denetim altında tutabilmek için Bursa’nın Yunan kuvvetlerince işgaline, işgali kolaylaştırmak için de Mudanya ve Gemlik’in İngiliz kuvvetlerince işgal edilmesine 4 Temmuz 1920’de karar vermiştir. Bursa’nın işgaliyle, İstanbul’un ve Boğazların kontrol altında tutulması amaçlanmıştır. Ancak, İstanbul hükûmetinin propagandasıyla işgalin amacı, millî kuvvetlerden kaynaklandığı iddia edilen “asayiş sorununu çözmek” olarak gösterilmiştir. 22 Haziran 1920’de başlayan Yunan ileri harekâtına karşı, ilk kez olarak Bursa’nın batısında savunma yapılmasına karar verilmiştir. Fakat İstanbul hükûmetinin Millî Mücadele aleyhinde yaptığı etkili propaganda, Bursa’yı savunacak olan 56’ncı Tümenin askerleri arasında yaygın olarak firarların yaşanmasına sebep olmuştur. Firarlar nedeniyle birliklerin etkinliklerinin ortadan kalkmasına, Mudanya ve Gemlik’in İngiliz kuvvetlerince işgal edilmesiyle geri çekilme yollarının kesilmesi ihtimali de eklenince, Bursa’nın batısında yapılmaya çalışılan savunma başarılı olamamıştır. Yunan kuvvetlerinin Eskişehir yönündeki harekâtına engel olabilmek için, Bursa’nın tahliye edilmesi zorunluluğu ortaya çıkmış, tahliye sonrasında Bursa’nın yönetimini devralmak üzere mahalli bir heyetin seçimi yapılmıştır. Heyet, yapılan propaganda sonucu Bursa’nın işgal nedenini, “asayiş sorunu” olarak görmüş ve asayişin sağlanacağı garantisini vererek, işgali önlemek için girişimde bulunmak istemiştir. Fransızları aracı ederek İngilizlerle görüşmek amacında olan heyetin bu girişimini Mustafa Kemal Paşa, Fransızlar aracılığıyla İngilizlerin himayesine girmek olarak görmüş ve engellemiştir. Yakınlığı sebebiyle zaten İstanbul hükûmetinin etkisi altında bulunan Bursa, yapılan propagandanın etkisiyle, askerî birliklerin firarlarla dağılması sonucunda savunulamamış ve Yunan kuvvetleri tarafından 8 Temmuz 1920’de işgal edilmiştir.