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Conference Object Citation - WoS: 7Citation - Scopus: 7Effect of Hardening Models on Different Ductile Fracture Criteria in Sheet Metal Forming(Springer France, 2016) Dizaji, Shahram Abbasnejad; Darendeliler, Haluk; Kaftanoglu, BilginPrediction of the fracture is one of the challenging issues which gains attention in sheet metal forming as numerical analyses are being extensively used to simulate the process. To have better results in predicting the sheet metal fracture, appropriate ductile fracture criterion (DFC), yield criterion and hardening rule should be chosen. In this study, the effects of different hardening models namely isotropic, kinematic and combined hardening rules on the various uncoupled ductile fracture criteria are investigated using experimental and numerical methods. Five different ductile fracture criteria are implemented to a finite element code by the user subroutines. The criterion constants of DFCs are obtained by the related experimental tests. The in-plane principle strains obtained by the finite element analyses for different DFCs are compared with the experimental results. Also, the experimental results are used to evaluate the principle strain values calculated by the finite element analysis for different combinations of DFCs and hardening rules. It is shown that some DFCs give better predictions if the appropriate hardening model is employed.Article Citation - WoS: 5Citation - Scopus: 5Development and Psychometric Analysis of a Pediatric Oncology Nurses' Educational Needs Scale(Wiley, 2023) Kudubes, Asli Akdeniz; Semerci, Remziye; Ozbay, Sevil Cinar; Ay, Ayse; Boztepe, HandanBackground/objectivesIt is important to determine the educational needs of pediatric oncology nurses in order to maximize and implement nursing care interventions. Therefore, this study aims to develop a valid and reliable measurement tool to determine pediatric oncology nurses' educational needs and examine its psychometric properties. Design/methodsThis methodological study was conducted with 215 pediatric oncology nurses in Turkey between December 2021 and July 2022. Data were collected with the "Nurse Information Form" and "Pediatric Oncology Nurses' Educational Needs Scale." IBM SPSS 21.0 and IBM AMOS 25.0 software programs were used for data analysis, and descriptive statistics were used to analyze numeric variables. Exploration and confirmatory factor analyses were performed to determine the scale's factorial structure. ResultsThe factorial analysis was used to test the structural validity of the scale. A five-factor structure consisting of 42 items was developed. The Cronbach's alpha coefficient for "Illness" was .978, "Chemotherapy and Side Effect" was .978, "Another Therapy and Side Effect" was .974, "Palliative Care" was .967, "Supportive Care" was .985, and the total score was .990. Fit indices resulting from the study were chi(2)/SD: 3.961, root mean square error of approximation (RMSEA): 0.072, goodness-of-fit index (GFI): 0.95, comparative-of-fit index (CFI): 0.96, and normed fit index (NFI): 0.95. ConclusionThe Pediatric Oncology Nurses' Educational Needs Scale is a valid and reliable scale for pediatric oncology nurses to determine their educational needs.Article Citation - WoS: 14Citation - Scopus: 14Analysis of Temperature-Dependent Forward and Leakage Conduction Mechanisms in Organic Thin Film Heterojunction Diode With Fluorine-Based Pcbm Blend(Springer, 2020) Yildiz, D. E.; Gullu, H. H.; Toppare, L.; Cirpan, A.The forward and reversed biased current-voltage behaviors of the organic diode were detailed in a wide range of temperatures. In this diode, a donor-acceptor-conjugated copolymer system was constructed with poly((9,9-dioctylfluorene)-2,7-diyl-(2-dodecyl-benzo[1,2,3]triazole)) as a partner of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). Two-order of magnitude rectification ratio was achieved, and the temperature-dependent values of saturation current, zero-bias barrier height, and ideality factor were extracted according to the thermionic emission model. The temperature responses of these diode parameters showed an existence of inhomogeneity in the barrier height formation. As a result, the observed non-ideal behavior was explained by Gaussian distribution of barrier height where low-barrier regions are effective in the forward biased conduction mechanism at low temperatures. Together with this analysis, series resistances were evaluated using Cheung's functions and also density of interface states were investigated. On the other hand, reverse biased current flow was found under the dominant effect of Poole-Frenkel effects associated with these interfacial traps. The reverse current conduction mechanism was detailed by calculating characteristic field-lowering coefficients and barrier height values in the emission process from the trapped state in the range of temperatures of interest.Article Citation - WoS: 3Evaluation of the Effects of Avatar on Learning Temporomandibular Joint in a Metaverse-Based Training(Wiley, 2024) Basmaci, Fulya; Bulut, Ali Can; Ozcelik, Erol; Ekici, Saliha Zerdali; Kilicarslan, Mehmet Ali; Cagiltay, Nergiz ErcilPurposeAvatars, representing users in the digital world, can influence users' behavior and attitudes. This study evaluates the impact of representing dental students receiving temporomandibular joint (TMJ) education in the metaverse via an anonymous or identified avatar.MethodsParticipants included 80 dental students in their fourth and fifth years of study. They were randomly assigned to either the avatar group (identified avatar) or the control group (anonymous avatar). Prior to training, participants completed a demographic questionnaire and a pretraining knowledge assessment. TMJ training was conducted in the metaverse for both groups. Pre- and post-training assessments included the Spielberger State-Trait Anxiety Inventory and a shyness scale to ensure group comparability. A post-test consisting of five questions was administered to both groups after 2 weeks of training.ResultsThere were no significant differences in pretraining scores for prior knowledge (p = 0.67), trait anxiety (p = 0.28), state anxiety (p = 0.92), or shyness (p = 0.42) between the avatar and control groups, indicating comparability at baseline. Post-training analysis revealed significantly higher post-test scores in the avatar group (median = 80) compared to the control group (median = 60) (p = 0.03).ConclusionsMetaverse environments offer various benefits for students, educators, and educational institutions in health education programs. Representing learners and their identities in training environments can enhance learning outcomes.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: 2Citation - Scopus: 1The Continuity in Q of the Lupaş Q-Analogues of the Bernstein Operators(Academic Press inc Elsevier Science, 2024) Yilmaz, Ovgue Gurel; Turan, Mehmet; Ostrovska, Sofiya; Turan, Mehmet; Ostrovska, Sofiya; Turan, Mehmet; Ostrovska, Sofiya; Mathematics; MathematicsThe Lupas q-analogue Rn,q of the Bernstein operator is the first known q-version of the Bernstein polynomials. It had been proposed by A. Lupas in 1987, but gained the popularity only 20 years later, when q-analogues of classical operators pertinent to the approximation theory became an area of intensive research. In this work, the continuity of operators Rn,q with respect to parameter q in the strong operator topology and in the uniform operator topology has been investigated. The cases when n is fixed and n -> infinity have been considered. (c) 2022 Elsevier Inc. All rights reserved.Article Citation - WoS: 3Citation - Scopus: 3Drbem Solution of Mhd Flow With Magnetic Induction and Heat Transfer(Tech Science Press, 2015) Pekmen, B.; Tezer-Sezgin, M.; MathematicsThis study proposes the dual reciprocity boundary element (DRBEM) solution for full magnetohydrodynamics (MHD) equations in a lid-driven square cavity. MHD equations are coupled with the heat transfer equation by means of the Boussinesq approximation. Induced magnetic field is also taken into consideration. The governing equations in terms of stream function, temperature, induced magnetic field components, and vorticity are solved employing DRBEM in space together with the implicit backward Euler formula for the time derivatives. The use of DRBEM with linear boundary elements which is a boundary discretization method enables one to obtain small sized linear systems. This makes the whole procedure computationally efficient and cheap. The results are depicted with respect to varying physical parameters such as Prandt1 (0.005 <= Pr <= 1), Reynolds (100 <= Re <= 2500), magnetic Reynolds (1 <= Rein <= 100), Hartmann (10 <= Ha <= 100) and Rayleigh (10 <= Ra <= 10(6)) numbers for discussing the effect of each parameter on the flow and temperature behaviors of the fluid. It is found that an increase in Ha slows down the fluid motion and heat transfer becomes conductive. Centered square blockage causes secondary flows on its left and light even for small Re. Strong temperature gradients occur around the blockage and near the moving lid for increasing values of Ra.Article Citation - WoS: 11Citation - Scopus: 12Some Fixed Point Results on Interpolative Metric Spaces(Pergamon-elsevier Science Ltd, 2025) Karapinar, Erdal; Agarwal, Ravi P.This paper aims to introduce some basic fixed point theorems on interpolative metric space that is a natural extension of standard metric space.Article Citation - WoS: 1Citation - Scopus: 2On the First Time of Ruin in Two-Dimensional Discrete Time Risk Model With Dependent Claim Occurrences(Taylor & Francis inc, 2018) Eryilmaz, SerkanThis article is concerned with a two-dimensional discrete time risk model based on exchangeable dependent claim occurrences. In particular, we obtain a recursive expression for the finite time non ruin probability under such a dependence among claim occurrences. For an illustration, we define a bivariate compound beta-binomial risk model and present numerical results on this model by comparing the corresponding results of the bivariate compound binomial risk model.Article Citation - WoS: 5Citation - Scopus: 7G-Csf Treatment of Healthy Pediatric Donors Affects Their Hematopoietic Microenvironment Through Changes in Bone Marrow Plasma Cytokines and Stromal Cells(Academic Press Ltd- Elsevier Science Ltd, 2021) Aerts-Kaya, Fatima; Kilic, Emine; Kose, Sevil; Aydin, Gozde; Cagnan, Ilgin; Kuskonmaz, Baris; Uckan-Cetinkaya, DuyguAlthough G-CSF mobilized peripheral blood stem cell (PBSC) transplantation is commonly used in adults, bone marrow (BM) is still the preferred stem cell source in pediatric stem cell transplantation. Despite the fact that G-CSF is increasingly being used to enhance the hematopoietic stem/progenitor cell (HSPC) yield in BM transplantation (G-BM), the direct effects of G-CSF on the pediatric BM microenvironment have never been investigated. The BM hematopoietic niche provides the physical space where the HSPCs reside. This BM niche regulates HSPC quiescence and proliferation through direct interactions with other niche cells, including Mesenchymal Stromal Cells (MSCs). These cells have been shown to secrete a wide range of hematopoietic cytokines (CKs) and growth factors (GFs) involved in differentiation, retention and homing of hematopoietic cells. Here, we assessed changes in the BM microenvironment by measuring levels of 48 different CKs and GFs in G-BM and control BM (C-BM) plasma from pediatric donors. In addition, the effect of G-CSF on cell numbers and characteristics of HSPCs and MSCs was assessed. IL-16, SCGF-b, MIP-1b (all >1000 pg/mL) and RANTES (>10.000 pg/mL) were highly expressed in healthy donor pediatric BM plasma. Levels of IL-3, IL-18, GROa, MCP-3 (p<0.05) were increased in G-BM, whereas levels of RANTES (p<0.001) decreased after G-CSF treatment. We found a negative correlation with increasing age for IL2-Ra and LIF (p<0.05). In addition, a concomitant increase in the number of both hematopoietic and fibroblast colony forming units was observed, indicating that G-CSF affects both HSPC and MSC numbers. In conclusion, G-CSF treatment of healthy pediatric donors affects the hematopoietic BM microenvironment by expansion of HSPC and MSC numbers and modifying local CK and GF levels.
