Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article An Interior Inverse Generalized Impedance Problem for the Modified Helmholtz Equation in Two Dimensions(Wiley-v C H verlag Gmbh, 2025) Yaman, Olha Ivanyshyn; Ozdemir, GaziWe consider the inverse interior problem of recovering the surface impedances of the cavity from sources and measurements placed on a curve inside of it. The uniqueness issue is investigated, and a hybrid method is proposed for the numerical solution. The approach takes advantages of both direct and iterative schemes, such as it does not require an initial guess and has an accuracy of a Newton-type method. Presented numerical experiments demonstrate the feasibility and effectiveness of the approach.Article Citation - WoS: 5Citation - Scopus: 5Light-Induced, Liquid Crystal-Templated Fabrication of Large-Area Pure Nanoporous Gold Films With High-Density Plasmonic Cavities(Amer Chemical Soc, 2024) Orhan, Ozan Baran; Polat, Nahit; Demir, Seren; Balci, Fadime Mert; Balci, SinanNanoporous gold (NPG) films are three-dimensional gold (Au) frameworks characterized by a uniform distribution of nanoscale irregular pores. Typically produced via a dealloying process, where the less noble silver (Ag) is selectively etched out, NPG films offer a large surface area, excellent chemical stability, remarkable catalytic activity, unique optical properties, and biocompatibility. These attributes make them invaluable for applications in catalysis, plasmonics, biosensors, and nanophotonics. However, the presence of residual Ag from the dealloying process can limit their performance in certain applications. In this study, we report a novel method for the fabrication of ultrapure, large-area NPG films (several cm2) using a light-induced and liquid crystal-templated method. A hexagonal lyotropic liquid crystal containing a strong acid and a nonionic surfactant is combined with an aqueous solution of HAuCl4, followed by the photochemical synthesis of gold nanoparticles (NPs) within the liquid crystal. After calcination of the Au NP-containing liquid crystal film at high temperature, pure NPG films are produced. We demonstrate surface-enhanced Raman spectroscopy (SERS) of Rhodamine 6G (R6G) molecules adsorbed on the NPG films and detect extremely low concentrations (below 10-6 M) of R6G. Additionally, we thoroughly investigated the formation and optical properties of the NPG films. The results reveal that the ultrapure NPG films contain high-density plasmonic nanocavities, where substantial electromagnetic fields are generated, leading to significant enhancement of optical processes at nanoscale dimensions.Article Citation - WoS: 2Citation - Scopus: 2The Unlimited Joy, 'once You Start You Can't Stop': Masculinity in Domestic Technology Commercials in Turkey(Taylor & Francis Ltd, 2024) Karaosmanoglu, Defne; Ata, Leyla Bektas; Emgin, BaharRecently, studies have begun examining men's interaction with domestic space to explore changing forms of masculinity and domesticity, arguing that housework has become a leisure activity for men, with domestic technologies serving as tools (toys) for them to engage with. In this article, we explore how men in Turkish television commercials of domestic technologies are portrayed and how these portrayals construct and reconstruct discourses of domesticity and masculinity. We aim to understand men's relationship with masculinity, home and domestic work in these commercials. Alongside leisure and fun, we explore the construction of discourses of masculinity and domesticity through specific themes such as the naughty scientist, the self-seeking purchaser, and the flirtatious chef. We argue that seeing more men on screen does not democratise domesticity since the equal share of workload at home is still far from being realised even in these portrayals. We also argue that domesticity is aestheticized with the participation of men and technology. Finally, women are used as instruments by men in reconstructing their masculinity through heterosexuality.Article Citation - WoS: 1Citation - Scopus: 2Concurrent Boron Removal From Reverse Osmosis Concentrate and Energy Production Using a Microbial Desalination Cell-Donnan Dialysis Hybrid System(Royal Soc Chemistry, 2024) Goren, A. Yagmur; Okten, H. EserThe removal of boron from aqueous solutions offers an important opportunity to improve the management of sustainable resources. In this regard, microbial desalination cells (MDCs) are a promising bioelectrochemical approach for effective water treatment, but the integrated MDC-Donnan Dialysis (DD) process for boron removal from reverse osmosis (RO) concentrated effluents has not been investigated before. Integration of the DD process with MDC is investigated in this paper for the first time to enhance the efficiency of the process by providing pre-treatment and natural pH manipulation. Therefore, the MDC process was evaluated for boron removal from boron-containing synthetic solution, geothermal water, and RO-concentrated effluent with the help of the DD system. The highest boron removal performance, with an efficiency of 72.1% in the desalination chamber and 74.8% in the DD-feed chamber, was obtained for boron-containing synthetic solution, while the COD removal efficiency was almost 90% in all water resources. However, the maximum power density was 4818 mW m-2 with a closed circuit voltage of 1317 mV for RO concentrated water treatment due to its high ionic strength. Moreover, the most crucial output of this study is that the pH value of the system did not need to be adjusted continuously to convert the uncharged boric acid into the borate ion in the charged form owing to better manipulation of the pH by the DD system. Overall, the integrated MDC-DD system provided promising results, presenting effective boron-containing water desalination, yeast wastewater treatment, and enhanced energy production.Article Citation - WoS: 10Citation - Scopus: 10Structural, Electronic, Vibrational, and Thermoelectric Properties of Janus Ge 2 P<i> X</I> (<i> X</I> = N, As, Sb, and Bi) Monolayers(Amer Physical Soc, 2024) Ozbey, Dogukan Hazar; Varjovi, Mirali Jahangirzadeh; Sargin, Gozde Ozbal; Sevincli, Haldun; Durgun, EnginTwo-dimensional (2D) Janus systems have garnered significant scientific interest owing to their novel properties and potential applications. The growing interest in these materials is driven by the idea that their structural asymmetry offers unprecedented opportunities for enhancing thermoelectric performance and unlocking groundbreaking advancements in energy conversion and waste heat utilization. In this context, we present a comprehensive study on the structural, vibrational, electronic, thermal, and thermoelectric properties of Janus Ge2PX(X = N, As, Sb, and Bi) monolayers, using first-principles calculations combined with the Landauer formalism. The suggested configurations exhibit dynamical stability and retain structural integrity even at elevated temperatures. Electronic structure calculations employing hybrid functionals (HSE06) with spin-orbit coupling reveal that Ge2PAs and Ge2PSb monolayers exhibit anisotropic characteristics as indirect semiconductors, while Ge2PN and Ge2PBi exhibit metallic behavior. We also compare the thermal, electronic, and thermoelectric transport properties of these proposed monolayers to binary 2D GeP in the ballistic limit. Notably, both Ge2PAs and Ge2PSb exhibit n-type figure of merit (ZT ) values exceeding 1 at 800 K, with their n-type ZT values surpassing that of GeP at room temperature. Our analysis underscores the distinctive structural and electronic properties of Ge2PAs and Ge2PSb monolayers, accompanied by their highly promising thermoelectric performance. These findings position them as strong candidates for energy harvesting and conversion applications.Article Citation - WoS: 5Citation - Scopus: 5Nonreciprocal Transmission Enabled by Time Modulation of Penetrable Metasurface Assisted by Surface Waves(Aip Publishing, 2024) Yilmaz, H. Onder; Yaman, FatihThis study introduces a novel approach to achieving nonreciprocal transmission by implementing time modulation to the bianisotropic metasurface. For the first time, we present the analytical solution of the excitation of anti-symmetric surface waves on penetrable metasurfaces depending on the excitation direction. Exploiting this finding, we numerically demonstrate asymmetric control of the transmission coefficient under a fast-time scale by employing solely time modulation. This approach lowers the complexity of the modulation scheme and implementation encountered in the space-time modulation technique. We develop and simulate a 3D unit cell model in the microwave domain, which forms a surface cavity that incorporates time-varying capacitors. The impedance transfer matrix method and harmonic balance numerical solutions are applied to the retrieved equivalent circuit for the numerical simulations. The results reveal optimized phase-coherent and incoherent nonreciprocal transmission at the significant isolation level ( >= 40 dB) for forward and backward transmissions. We discuss the consistency and discrepancies between numerical methods and consider the impact of the losses and nonlinearity on the metastructure performance. (c) 2024 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) licenseReview Citation - WoS: 10Citation - Scopus: 12Trends in Authentication of Edible Oils Using Vibrational Spectroscopic Techniques(Royal Soc Chemistry, 2024) Ozen, Banu; Cavdaroglu, Cagri; Tokatli, FigenThe authentication of edible oils has become increasingly important for ensuring product quality, safety, and compliance with regulatory standards. Some prevalent authenticity issues found in edible oils include blending expensive oils with cheaper substitutes or lower-grade oils, incorrect labeling regarding the oil's source or type, and falsely stating the oil's origin. Vibrational spectroscopy techniques, such as infrared (IR) and Raman spectroscopy, have emerged as effective tools for rapidly and non-destructively analyzing edible oils. This review paper offers a comprehensive overview of recent advancements in using vibrational spectroscopy for authenticating edible oils. The fundamental principles underlying vibrational spectroscopy are introduced and chemometric approaches that enhance the accuracy and reliability of edible oil authentication are summarized. Recent research trends highlighted in the review include authenticating newly introduced oils, identifying oils based on their specific origins, adopting handheld/portable spectrometers and hyperspectral imaging, and integrating modern data handling techniques into the use of vibrational spectroscopic techniques for edible oil authentication. Overall, this review provides insights into the current state-of-the-art techniques and prospects for utilizing vibrational spectroscopy in the authentication of edible oils, thereby facilitating quality control and consumer protection in the food industry. The authentication of edible oils has become increasingly important for ensuring product quality, safety, and compliance with regulatory standards.Article Citation - WoS: 3Citation - Scopus: 3Novel Injectable Calcium-Magnesium Phosphate Cement-Based Composites With Piezoelectric Properties: Advancements in Bone Regeneration Applications(Springer, 2024) Sakar, Neslihan; Albayrak, Aylin Ziylan; Karakaya, Merve; Adem, Umut; Tansel, TunayDesigning a novel injectable bone cement is an important approach to the success of bone healing in minimally invasive surgeries. As natural bone has a piezoelectric property, which is crucial in bone regeneration, this study focused on the development of a novel injectable composite bone cement with piezoelectric properties. For the composite composition, calcium and zirconium doped barium titanate (BCZT) was used for its piezoelectric property, while calcium phosphate and magnesium phosphate cement (CMPC) were preferred for its bone-like properties. In this framework, first BCZT, CMPC, and their composites were prepared, and their phase structures, particle size distributions, and piezoelectric and dielectric properties were investigated. Then, the composite bone cements were prepared by mixing CMPC with BCZT in three different ratios (20%, 30%, and 40%). Next, polysorbate 80 solution was added to the cement mixtures to prepare the injectable pastes. Finally, injectability, setting time, and compressive strength of the composites were assessed. As a result, the composite bone cement containing 30% BCZT has the potential to be used as an injectable bone cement in invasive orthopedic surgery.Article Citation - WoS: 1Citation - Scopus: 1Quantum Transport Regimes in Quartic Dispersion Materials With Anderson Disorder(Aip Publishing, 2024) Polat, Mustafa; Ozkan, Hazan; Sevincli, HaldunMexican-hat-shaped quartic dispersion manifests itself in certain families of single-layer two-dimensional hexagonal crystals such as compounds of groups III-VI and groups IV-V as well as elemental crystals of group V. A quartic band forms the valence band edge in various of these structures, and some of the experimentally confirmed structures are GaS, GaSe, InSe, SnSb, and blue phosphorene. Here, we numerically investigate strictly one-dimensional and quasi-one dimensional (Q1D) systems with quartic dispersion and systematically study the effects of Anderson disorder on their transport properties with the help of a minimal tight-binding model and Landauer formalism. We compare the analytical expression for the scaling function with simulation data to distinguish the domains of diffusion and localization regimes. In one dimension, it is shown that conductance drops dramatically at the quartic band edge compared to the quadratic case. As for the Q1D nanoribbons, a set of singularities emerge close to the band edge, suppressing conductance and leading to short mean-free-paths and localization lengths. Interestingly, wider nanoribbons can have shorter mean-free-paths because of denser singularities. However, the localization lengths sometimes follow different trends. Our results display the peculiar effects of quartic dispersion on transport in disordered systems. (c) 2024 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) licenseArticle Citation - WoS: 4Citation - Scopus: 4Anisotropic Single-Layer Tilted Α-Bi: Identification of Uniaxial Strain Via Raman Spectrum(Amer Chemical Soc, 2024) Dogan, Kadir Can; Yagmurcukardes, MehmetIn the present study, the structural, vibrational, electronic, and elastic properties of single-layer alpha-Bi are investigated by performing density functional theory-based first-principles calculations. Structural optimizations show that free-standing alpha-Bi possesses a tilted black phosphorus-like anisotropic structure. The phonon band dispersions and linear-elastic parameters reveal the dynamical and mechanical stability of the alpha-Bi structure, respectively. In addition, quantum molecular dynamics simulations indicate the thermal stability of the single layer at room temperature. Electronically, it is found that alpha-Bi exhibits an indirect band gap semiconducting behavior, whose hole and electron effective masses are shown to be orientation-dependent with the latter being more anisotropic. Such anisotropic effective masses reveal orientation-dependent transport properties in single-layer alpha-Bi. Moreover, the orientation-dependent elastic features of alpha-Bi show that at an angle of 45 degrees with respect to the zigzag (ZZ) orientation, an auxetic behavior is predicted for the structure. Furthermore, the impact of uniaxial strains along the two main orientations (ZZ and armchair directions) is investigated on the vibrational properties of single-layer alpha-Bi. The phononic stability of the structure is first predicted at the strain limits (+/- 5) for both directions, and the results reveal the preserved stability of the single layer under both compressive and tensile strains. The calculated Raman spectra under uniaxial strains show that the type (compressive or tensile) and the direction of the applied strain can be deduced from the Raman spectra analysis. Overall, strain-induced modifications in the Raman spectrum of 2D alpha-Bi in terms of the peak positions may be useful tools for the characterization of induced strain in experimental studies.