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Article Citation - WoS: 14Citation - Scopus: 15Yielding of Two-Layer Shrink-Fitted Composite Tubes Subject To Radial Pressure(Springer Heidelberg, 2005) Eraslan, AN; Akis, TYielding of two-layer shrink-fitted composite tubes with axially constrained ends subject to either internal or external pressure is investigated in detail. In the framework of small deformations, a state of plane strain and von Mises yield criterion, analytical expressions are obtained for critical values of the pressure leading to plastic flow. It is shown that, depending on material properties and tube dimensions, different modes of plastic deformation may occur. Yielding may commence at the inner tube or at the outer tube or simultaneously in both tubes. The conditions for different nature of plastic flow are determined. Using analytical expressions obtained for critical values of the parameters and properties of real engineering materials, various numerical examples are handled and the variation of elastic limit pressure with interference and interface radius is explained.Article Citation - WoS: 29Citation - Scopus: 36Fixed Point Results on a Class of Generalized Metric Spaces(Springer Heidelberg, 2012) Aydi, Hassen; Karapinar, Erdal; Lakzian, HosseinBrianciari ('A fixed point theorem of Banach-Caccioppoli type on a class of generalized metric spaces,' Publ. Math. Debrecen 57 (2000) 31-37) initiated the notion of the generalized metric space as a generalization of a metric space in such a way that the triangle inequality is replaced by the 'quadrilateral inequality,' d(x, y) <= d(x, a) + d(a, b) + d(b, y) for all pairwise distinct points x, y, a, and b of X. In this paper, we establish a fixed point result for weak contractive mappings T : X -> X in complete Hausdorff generalized metric spaces. The obtained result is an extension and a generalization of many existing results in the literature.Article Factors Influencing the Transition Time From Psoriasis to Psoriatic Arthritis: A Real-World Multicenter Analysis(Springer Heidelberg, 2025) Kilic, Gamze; Kilic, Erkan; Tekeoglu, Ibrahim; Sargin, Betul; Cengiz, Gizem; Balta, Nihan Cuzdan; Nas, KemalTo identify clinical and demographic predictors associated with the timing of transition from psoriasis (PsO) to psoriatic arthritis (PsA), and to compare the characteristics of patients with concurrent PsO-PsA onset versus those with prolonged transition. A multi-center, observational study was conducted using data from the Turkish League Against Rheumatism (TLAR) network including PsA patients fulfilling CASPAR criteria. Patients were categorized into two groups: Group 1 (concurrent PsO and PsA onset within +/- 1 year) and Group 2 (prolonged transition to PsA, > 1 year after PsO). Demographic, clinical, and laboratory characteristics, disease activity, and patient-reported outcomes were compared between groups. Logistic regression was employed to determine independent predictors of prolonged transition. Among 799 patients (mean age 46.8 +/- 12.3 years), 237 (29.7%) had concurrent onset and 562 (70.3%) had a prolonged transition, with a mean PsO-to-PsA interval of 12.9 +/- 9.6 years. Depression (p = 0.005) and fatigue levels (p = 0.011) were significantly higher in patients with prolonged transition to PsA. Multivariate analysis revealed that scalp psoriasis (OR = 7.162), nail psoriasis (OR = 3.270), family history of PsO (OR = 1.813), and enthesitis ever (OR = 2.187) were associated with prolonged transition. Conversely, family history of PsA (OR = 0.421) and older age at PsO onset (OR = 0.957) predicted shorter transition. Prolonged transition from PsO to PsA is influenced by distinct clinical and demographic factors. Scalp/nail psoriasis, family history of PsO, and enthesitis ever may signal higher risk for prolonged PsA onset. Recognizing these markers can support timely referral and intervention, minimizing diagnostic delay and improving long-term patient outcomes.Article Citation - WoS: 5Citation - Scopus: 7Emulating Erasmus? Turkey's Mevlana Exchange Program in Higher Education(Springer Heidelberg, 2019) Yilmaz, GozdeIn today's world, globalization and internationalization of education necessitate new initiatives to catch the new era. Turkey, as a country in between the east and the west, attempts to do so through its recent exchange program in higher education. Interestingly, Turkey's Mevlana exchange program as an ambitious project in higher education denotes an instance of policy transfer: taking the EU model (i.e., Erasmus) and slightly adjusting it to the national circumstances. This article unpacks Turkey's Mevlana program to demonstrate the process of policy transfer by focusing on different questions posed within the policy transfer literature. It argues that Mevlana is drawn from Erasmus, and it is created as a tool of soft power that is increasingly exercised by Turkey due to its changing focus within the Turkish foreign policy of 2000s.Article Citation - WoS: 21Citation - Scopus: 21A Study on the Dark and Illuminated Operation of Al/Si3< Schottky Photodiodes: Optoelectronic Insights(Springer Heidelberg, 2024) Surucu, Ozge; Yildiz, Dilber Esra; Yildirim, MuratThis work extensively investigates the operation of an Al/ Si3N4/p-Si Schottky-type photodiode under dark and varying illumination intensities. The photodiode is fabricated by employing the metal-organic chemical vapor deposition (MOCVD) method. A thorough electrical characterization is performed at room temperature, encompassing measurements of current-voltage (I-V), current-time (I-t), capacitance-time (C-t), and conductance time (G-t). The photodiode's rectification factor and reverse bias area increased under illumination. The relationship between light power density, barrier height, and diode ideality factor is found. The study also found a strong correlation between light intensity and applied voltage on series resistance (R-s) and shunt resistance (R-sh). R-s values are calculated using Cheung's functions, revealing the diode's resistance behavior. The study also examines the photodiode's photoconductivity and photoconductance, finding a non-linear relationship between photocurrent and illumination intensity, suggesting bimolecular recombination. Calculated photosensitivity (K), responsivity (R), and detectivity (D*) values show the device's light response effectiveness, but efficiency decreases at higher illumination intensities. Transient experiments indicate stable and reproducible photocurrent characteristics, revealing photogenerated charge temporal evolution. This study provides a complete understanding of the Al/Si3N4/p-Si Schottky photodiode's behavior under different illumination intensities. The findings advance optoelectronic device knowledge and enable their use in advanced technologies.Letter Theoretical Modelling of Magnetron Sputtering of Boron Nitride Coating(Springer Heidelberg, 2023) Rake, Nakka; Kaftanoglu, Bilgin; Hacaloglu, Tugce; Aydogan, AsudeThe fundamentals of the magnetron sputtering (MS) technique are simple. However, the complex interplay of various physical and chemical sub-processes lies in its simplicity. The direct simulation Monte Carlo (DSMC) method is used to model the MS of the Boron Nitride (BN) coating. The Lorentz force, which is created by an electric field, magnetic field and particle collision, is utilised to model the BN coating. Three distinct bias voltages are used to generate three different BN-coating models under the same conditions. The modelling of BN coatings reveals that the deposition rate decreases as the substrate voltage increases.Article Citation - WoS: 162Citation - Scopus: 167Economic Policy Uncertainty, Energy Consumption and Carbon Emissions in G7 Countries: Evidence From a Panel Granger Causality Analysis(Springer Heidelberg, 2020) Pirgaip, Burak; Dincergok, BurcuWe investigate the causal relationship between economic policy uncertainty (EPU) and energy consumption and carbon (CO2) emissions in G7 countries. We employ a bootstrap panel Granger causality test developed by Konya (Econ Model 23:978-992, 2006), using a yearly data set spanning from 1998 to 2018. Our test results provide significant support for a unidirectional causality running from EPU to energy consumption in Japan; from EPU to CO2 emissions in the USA and Germany; and from EPU to both energy consumption and CO2 emissions in Canada. In Italy, causality runs from CO2 emissions to EPU, but a bidirectional causality between EPU and energy consumption exists as well. We also explore a unidirectional causality that runs from energy consumption to CO2 in the USA. Based on the overall findings, we draw important implications for policymakers and we strongly recommend for G7 countries to take into account possible negative effects of EPU on energy conservation policies, which should be embarked upon to reduce energy consumption and CO2 emissions, as committed in their recent climate mandate.Article Citation - WoS: 3Citation - Scopus: 6Experimental Analysis of the Behavior of Composite Column-Reinforced Concrete Beam Joints(Springer Heidelberg, 2021) Tunc, Gokhan; Dakhil, Abdulrrahman; Mertol, Halit CenanThis study assesses the seismic performance of steel-reinforced concrete (SRC) composite columns connected to reinforced concrete (RC) beam joints, and their ability to dissipate seismic energy through inelastic deformations. In this article, experimental aspects regarding the seismic performance of high-ductility and low-ductility steel-concrete composite frame were investigated. The principle design parameter in this study was ductility, which is considered a conceptual framework in Efficiency-Based Seismic Engineering. Thus, attention was focused on assuring various ductility ranges of joints obtained through a detailed study of the Turkish Earthquake Code (TEC 18) [Ministry of Public Works and Housing.: Turkiye Bina Deprem Yonetmeligi (Turkey's Earthquake Code for Buildings). Official Gazette (2018) (in Turkish).]. After identifying deficiencies and the energy dissipation capacity in the newly proposed joints, two half-scaled frames with specific ductility-related designs were constructed, instrumented, tested, and analyzed. The specimens were tested under displacement-controlled lateral cyclic loading that incorporated constant axial loading to create cyclic tension and compression facets across the joint areas. The test results proved that the SRC column-RC beam frames employing an extra column reinforcement ratio exhibit slightly better seismic performance. Due to the presence of structural steel, the shear failure of the joint was effectively prevented, even after the formation of the plastic hinge on the interface of the beam. During the testing, the column rebars, to some extent, made a minor contribution to the joint strength of the specimen compared to the structural steel that absorbed almost all of the load applied to the frame.Article Citation - WoS: 10Citation - Scopus: 11Determination of the Relationship Between Uniaxial and Triaxial Swelling Equations for Clay Bearing Rocks(Springer Heidelberg, 2013) Bilir, M. Erdinc; Sari, Y. Dursun; Ozarslan, Ahmet; Genis, Melih; Sel, IbrahimDesign in swelling mediums is mostly based on uniaxial data since the standards proposed by the International Society for Rock Mechanics Commission on Swelling Rocks for uniaxial tests are in the form of recommendations, triaxial sets are not highly available; and there is no standard developed for triaxial tests. The main purpose of this study is to define the relationship between the uniaxial and the triaxial swelling equations and to predict the triaxial values using the uniaxial data. The other purpose of the study is to contribute to the development of the standards and to expand the data available in the literature about triaxial swelling behavior. Numerous uniaxial and triaxial swelling tests were performed on the samples from seven different locations, in Turkey, in a state of the art swelling laboratory. As a result of the determination of the triaxial swelling behavior of these samples, the relationships between the uniaxial and the triaxial swelling data for the individual samples as well as the whole set of samples are expressed by the equations derived from the statistical analyses.Article Citation - WoS: 12Citation - Scopus: 11Integrated Approach for Determining Spatio-Temporal Variations in the Hydrodynamic Factors as a Contributing Parameter in Landslide Susceptibility Assessments(Springer Heidelberg, 2019) Canoglu, Mustafa Can; Aksoy, Husnu; Ercanoglu, MuratAlthough general approaches to the effect of water on the mechanisms causing landslides have been adopted, the work presented in this paper was carried out to quantify the landslide susceptibility variation in space and time, integrating the soil moisture distribution and routing (SMDR) model and landslide susceptibility concept. The approach proposed in the present study reflects the temporal effects of the saturation degree index (SDI) on landslide susceptibility as a new index to understand the effect of soil saturation. The topographic wetness index (TWI) is a conventional parameter that represents the relative wetness on landsliding. The new proposed landslide susceptibility approach is used in the study area to understand the effect of soil saturation and the emergence of the Dereba landslide in the study area. The comparative results of landslide susceptibility maps obtained from the new approach utilizing the proposed SDI and conventional TWI are remarkable. Accordingly, a new substantial method is proposed using the attainable monthly mean meteorological data to generate monthly landslide susceptibility maps. The results obtained for the Dereba landslide using the proposed method are validated with the other landslide that has occurred in the same watershed. The results revealed that the approach proposed in this study was compatible with the landslide mechanism in the study area and may help to express the water effect in landslide susceptibility analyses.
