Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 1Citation - Scopus: 1Completeness of Energy Eigenfunctions for the Reflectionless Potential in Quantum Mechanics(Aip Publishing, 2024) Erman, Fatih; Turgut, O. TeomanThere are a few exactly solvable potentials in quantum mechanics for which the completeness relation of the energy eigenstates can be explicitly verified. In this article, we give an elementary proof that the set of bound (discrete) states together with the scattering (continuum) states of the reflectionless potential form a complete set. We also review a direct and elegant derivation of the energy eigenstates with proper normalization by introducing an analog of the creation and annihilation operators of the harmonic oscillator problem. We further show that, in the case of a single bound state, the corresponding wave function can be found from the knowledge of continuum eigenstates of the system. Finally, completeness is shown by using the even/odd parity eigenstates of the Hamiltonian, which provides another explicit demonstration of a fundamental property of quantum mechanical Hamiltonians.Article Citation - WoS: 3Citation - Scopus: 3Two Decades of Research on Roma in Türkiye: Socioeconomic Exclusion, Identity, and State Policies(Liverpool Univ Press, 2024) Celik, Faika; Uştuk, Ozan; Ustuk, OzanThe scholarly investigation of Roma communities in Turkiye has intensified since the 2000s, largely driven by Turkiye's EU accession candidacy and subsequent adaptation process. This alignment, along with internal developments, prompted governments to prioritize Roma issues, implement projects, and issue action plans. The Roma Civil Society Movement in the 1990s further highlighted Roma challenges, resulting in a diverse body of literature. This study critically examines academic literature to map prevailing trends and thematic foci. Key areas of scholarly engagement include the various dimensions of socio-economic exclusion faced by Roma in education, employment, housing, and health. Additionally, scholars analyze how Roma negotiate and resist pejorative representations, construct their identities, and organize to address contemporary challenges. State policies affecting Roma, from past to present, also receive considerable attention. By critically engaging with this scholarship, the present study highlights significant progress and ongoing challenges in Romani Studies in Turkiye, offering insights into future research directions.Article Machinability Investigation on Cnc Milling of Recycled Short Carbon Fiber Reinforced Magnesium Matrix Composites(Iop Publishing Ltd, 2024) Atasoy, Sahin; Kandemir, SinanThis study investigates the machinability of magnesium matrix composites reinforced with short carbon fibers, which represent novel materials in the field. AZ91 alloy and its composites containing 2.5 and 5 wt% recycled carbon fiber (rCF) reinforcements were used as workpieces. Face milling was conducted using uncoated carbide cutting tools under dry cutting conditions with varied cutting speeds (480-560-640 m min(-1)) and feed rates (0.65-0.8-0.95 mm min(-1)). The experimental design was based on the Taguchi L-9 (3(3)) orthogonal array. Analysis included cutting forces, surface roughness, wear on cutting inserts, and chip morphology to assess machinability. Taguchi, analysis of variance, and regression methods were employed to analyze cutting force and surface roughness results. Findings indicated satisfactory machinability for AZ91 alloy and comparatively poorer performance for the 5 wt% rCF reinforced composite, with increased reinforcement content correlating with higher cutting force and surface roughness. SEM and EDX analyses revealed significant built-up layer formation on cutting inserts, with predominantly spiral-shaped continuous chips observed in the experiments. Overall, the study affirmed the machinability of the composites and identified suitable cutting parameters for further investigations.Article Citation - WoS: 2Citation - Scopus: 2Exploring the Use of Water-Extracted Flaxseed Hydrocolloids in Three-Dimensional Cell Culture(Mary Ann Liebert, inc, 2024) Yildirim-Semerci, Ozum; Bilginer-Kartal, Rumeysa; Arslan-Yildiz, AhuPlant-derived hydrocolloids offer promising prospects in biomedical applications. Among these, Flaxseed hydrocolloid (FSH) can form a soft, elastic, and biocompatible hydrocolloid with tunable viscosity and superior swelling capacity, making it an attractive scaffold. This study introduces a green extraction method for FSH, employing a single-step aqueous extraction process and fabrication of FSH scaffold. Despite growing interest, the pristine form of FSH has not been investigated for sustainable long-term three-dimensional (3D) cell culture. Here, FSH scaffolds were thoroughly characterized for their morphological, chemical, mechanical, and biological properties. 3D cell culture experiments were conducted using NIH-3T3 mouse fibroblast cells, and cell viability was assessed using live/dead and Alamar Blue assays. High cell viability was sustained for long term compared with 2D cell culture. Cell adhesion and 3D cellular morphology on FSH scaffold for 30 days were monitored by scanning electron microscopy analysis. Also, collagen type-I and F-actin expressions were analyzed by immunostaining after 30 days of culture, resulting in 5- and 4-fold increments of fluorescence intensity, respectively. Results indicate sustained cell viability in the long term and favorable cell-material interaction, demonstrating the potential of FSH as a scaffold. This study emphasizes the importance of the green extraction approach, improving the biocompatibility and functionality of FSH tissue engineering applications. Impact Statement Flaxseed hydrocolloid (FSH) is a promising scaffold for biomedical applications due to its biocompatibility and tunable properties. This study introduces a green extraction method for FSH and evaluates its use in 3D cell culture with NIH-3T3 mouse fibroblast cells. The findings indicate high cell viability and enhanced cell-material interactions over 30 days, highlighting the potential of FSH for tissue engineering.Article Citation - WoS: 1Citation - Scopus: 1Chemical Composition Optimization and Isothermal Transformation of Δ-Transformation Plasticity Steel for the Third-Generation Advanced High-Strength Steel Grade(Wiley-v C H verlag Gmbh, 2024) Okur, Onur; Davut, Kemal; Palumbo, Gianfranco; Nalcaci, Burak; Guglielmi, Pasquale; Yalcin, Mustafa Alp; Erdogan, MehmetA new low-manganese transformation-induced plasticity steel is designed with optimized nickel content to achieve superior strength and ductility while minimizing the use of expensive nickel. The steel is optimized using JMatPro software, then cast, and hot rolled. To assess the effect of intercritical annealing on austenite (martensite at room temperature) volume fraction and carbon content, hot-rolled steel samples quenched from different annealing temperatures (680-1100 degrees C) are used. Additionally, hot-rolled steel coupons are intercritically annealed at about 50% austenite formation temperature (740 degrees C) and then subjected to isothermal treatments at 300-425 degrees C for varying times (10-90 min). After optimizing these treatments to maximize retained austenite (RA), tensile specimens are heat-treated first at 740 degrees C and then isothermally at 325 degrees C. Thermodynamic calculations suggest that aluminum combined with silicon may lead to the delta ferrite formation, and even minimal nickel content can stabilize a considerable amount of austenite. In the experimental studies, it is shown that lower-temperature bainitic holding enhances austenite stability by enriching the carbon content. Optimized two-stage heat treatments yield up to 25.8% RA, with a tensile strength of 867.2 MPa and elongation of 40.6%, achieving a strength-elongation product of 35.2 GPax%, surpassing the third-generation advanced high-strength steel grades minimum requirement of 30 GPax%.Article Effect of Random Structural Variations on the Optical Properties of Honeycomb Photonic Crystals(Taylor & Francis Ltd, 2024) Tuncturk, Yigit; Sozuer, H. SamiPeriodic dielectric structures called photonic crystals are being used in various sensors and devices. Since photonic crystals are designed to operate within certain frequency ranges, accuracy in structure becomes important. In this work, we investigate the effects of two types of randomness, surface roughness and positional randomness, on the optical properties of the honeycomb photonic crystal. We employed the plane wave expansion method to investigate the effects of random perturbations of the shape and the position of the structure on the density of states. We also employ the finite-difference time-domain method to calculate the transmission spectrum as a consistency check. We find that both surface roughness and positional imperfections cause significant changes in the DOS. As the degree of randomness is increased, transverse electric and transverse magnetic gaps are narrowed and complete gaps totally disappear at $ 45\% $ 45% of surface roughness.Article On the Rings Whose Injective Right Modules Are Max-Projective(World Scientific Publ Co Pte Ltd, 2024) Alagoz, Yusuf; Buyukasik, Engin; Yurtsever, Haydar BaranRecently, right almost-QF (respectively, max-QF) rings that is the rings whose injective right modules are R-projective (respectively, max-projective) were studied by the first two authors. In this paper, our aim is to give some further characterizations of these rings over more general classes of rings, and address several questions about these rings. We obtain characterizations of max-QF rings over several classes of rings including local, semilocal right semihereditary, right non-singular right Noetherian and right non-singular right finite dimensional rings. We prove that for a ring R being right almost-QF and right max-QF are not left-right symmetric. We also show that right almost-QF and right max-QF rings are not closed under factor rings. This leads us to consider the rings all of whose factor rings are almost-QF and max-QF.Article Citation - WoS: 2Citation - Scopus: 2Mapk Pathway and Nis in B-Cpap Human Papillary Thyroid Carcinoma Cells Treated With Resveratrol(Elsevier Gmbh, 2024) Kocabas, Gokcen Unal; Blatti, Asli Kisim; Berdeli, Afig; Ozgen, Ahmet Gokhan; Yurekli, Banu SarerBackground: Resveratrol, a herbal phytoalexin, is known to have anti-tumor effects in several tumors including thyroid cancer cells. Aim: The aim of this study was to determine the effects of resveratrol on the expression of BRAF, ERK and NIS mRNA levels and protein expression in B-CPAP human thyroid papillary cancer cell line. Methods: B-CPAP cells were treated with resveratrol at concentrations of 10-100 mu M for 24-48-72 h. Cell viability was assessed by XTT Cell Proliferation Assay. BRAF, ERK and NIS mRNA levels were evaluated by rtPCR method. Protein expressions were evaluated by Western Blot method. Results: Resveratrol was found to inhibit cell proliferation in a time and dose dependent manner. The IC50 values of resveratrol were 18.7 mu M and 56.8 mu M after 48 h and 72 h respectively. Resveratrol treatment of B-CPAP cells resulted in up to 1.5-fold reduction in BRAF mRNA and up to 5.5 fold reduction in ERK mRNA levels. NIS mRNA levels showed up to 3-fold increase. Western Blot studies confirmed the rt- PCR results with a decrease in BRAF and ERK, and increase in NIS protein expressions. Conclusion: This study demonstrated that resveratrol inhibits thyroid papillary carcinoma cell proliferation and reduces poor prognostic BRAF and ERK mRNA and protein expressions, while increasing NIS mRNA and protein expression suggesting a redifferentiating effect. More studies are needed to evaluate resveratrol as a novel therapeutic agent in the treatment of papillary thyroid cancer.Article Thermal Mixing Analysis in a Ladle Utilizing Physical and Numerical Modeling Through Planar Laser-Induced Fluorescence (plif) Technique(Iron and Steel Institute of Japan, 2024) Amaro-Villeda,A.; Dutta,A.; Guevara-Castillo,M.; Jardón-Pérez,L.E.; Ramírez-Argáez,M.A.Thermal mixing during the gas stirring operation and arc heating in a steel ladle is analyzed through the modern tools of a physical model using PIV (Particle Image Velocimetry) and thermal PLIF (Planar Laser Induced Fluorescence), whose velocity and temperature fields were used to fine-tune and validate a multiphase Eulerian two-phase mathematical model. Agreement on both fluid dynamics and thermal evolution is reasonably good between experiments and the predictions obtained by the mathematical model of the physical model. The analysis coming from the numerical model validated by the physical model measurements included the thermal mixing and energy efficiency of single nozzle injection in centric and eccentric (4/5R) gas injection. It turned out that energy efficiency in the centric gas injection is 20% more efficient than in eccentric injection. Then, under the same heat flux provided, the maximum temperature of the water in the centric gas injection would be higher than the maximum temperature reached in the eccentric mode with the same gas flow rate. Good heat transfer happens when the heat source impinges in a fluid region with high circulation and turbulent dispersion. © 2024 The Iron and Steel Institute of Japan.Article Citation - Scopus: 11Non-Linear Regional Income Divergence and Policies: Turkey Case(Hellenic Association of Regional Scientists, 2015) Duran,H.E.The literature on economic convergence is strongly influenced by Neo-Classical Growth model. It describes a monotone saddle path along which each economy converges towards a unique steady state. Commonly employed method in convergence analysis is the linear cross-sectional regressions which links the annual growth rate of regions to their initial income level. Ignoring the non-linearities is important from a policy perspective that implications obtained from a linear regression can be very different to the policies learned from a nonlinear case. Aim of the present study is to analyze regional income convergence in Turkey by using nonparametric convergence regressions. We implement our study for 67 provinces and a period 1975-2000. We find that the relationship between initial income and growth takes a inverted-U shape which means that the very low-income and high-income group of provinces experince a slow growth pattern compared to middle-income group. This has several implications for regional economic policies. First, middle-income provinces are able to stimulate their economies and fulfill their potential for convergence by market forces. Second, however, the very low-income provinces need a substantial help and assistance.It, therefore, becomes a natural necessity to direct policy instruments such as subsidies, direct and indirect income transfers, tax exemptions and other resources to these areas. In this way, nonparametric estimations provide a very useful guide to the way how the resources should be allocated across provinces. © 2015 Hellenic Association of Regional Scientists. All rights reserved.