Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Güler, Ömer(32)
- Akkurt, Nevzat(27)
- Tekin, H.O.(27)
- ALMisned, Ghada(24)
- Gul, Muhammet(20)
- Yucesan, Melih(14)
- Xu, Qian(12)
- Baykal, Duygu Sen(11)
- Güler, Seval Hale(11)
- Taşgın, Yahya(10)
- Kavaz, E.(9)
- Kilic, G.(8)
- Zengin, Gokhan(8)
- Durmus, Hasan(7)
- Guler, Omer(7)
- Xiong, Yaxuan(7)
- Yılmaz, Demet(7)
- Özkul, İskender(7)
- Yayla, Nihal(6)
- Zhang, Hui(6)
- Alkarrani, Hessa(5)
- Baloglu, Ulas Baran(5)
- Celik, Erkan(5)
- Du, Yanping(5)
- Ilik, E.(5)
- Kanca, M. Sait(5)
- Kök, Mediha(5)
- Mahomoodally, Mohamad Fawzi(5)
- Ortiz-Barrios, Miguel(5)
- Qiang, Yujie(5)
- Yang, Gang(5)
- Zakaly, Hesham M.H.(5)
- Aghakhani, S.(4)
- Basgoz, Oykum(4)
- Birdogan, Selcuk(4)
- Caprioli, Giovanni(4)
- Etli, Serkan(4)
- Guler, Seval Hale(4)
- Kahraman, Gökhan(4)
- Liu, Lin(4)
Yayınlar
- MakaleYalnız künye2027Scopus SJRQ2Design, structural characterization, and simulated radiation-transport assessment of high-entropy (GdErSmEuYb)2X2O7 (X = Hf, Zr, Ce, Si) rare-earth oxides
Güler, Ömer; Güler, Seval Hale; Yayla, Nihal; Baykal, Duygu Sen; Durmus, Hasan; Tekin, Huseyin Ozan; ALMisned, Ghada
This study investigates the structural, microstructural, surface-chemical, and radiation attenuation behaviour of high-entropy rare-earth oxide (HEO) powder compositions synthesized as TBC-related candidate coating materials, whose radiation attenuation potential was assessed within a computational Inconel-718-based sandwich model. Four compositions, namely (GdErSmEuYb)2Hf2O7, (GdErSmEuYb)2Ce2O7, (GdErSmEuYb)2Zr2O7, and (GdErSmEuYb)2Si2O7, were synthesized via high-energy ball milling followed by calcination at 1200 °C. X-ray diffraction results revealed the formation of distinct crystal structures depending on B-site chemistry, including defective fluorite and silicate-type phases. SEM-EDS mapping confirmed homogeneous elemental distribution, while XPS analysis demonstrated mixed valence states and different oxygen vacancy concentrations across the compositions. To evaluate radiation attenuation performance, a sandwich-type geometry consisting of a 10 mm Inconel-718 core with symmetrically defined simulated HEO layers was modelled using Monte Carlo simulations. Gamma-ray transmission was analyzed over an energy range of 0.276-1.332 MeV, and fast neutron attenuation was assessed at 4.5 MeV. The results showed that transmission factors decreased with increasing coating thickness, with the effect being more pronounced at lower photon energies. Among the investigated compositions, the Hf-based system exhibited the most favorable predicted attenuation response for both gamma rays and fast neutrons under the defined simulation conditions. Theoretical half-value layer calculations also showed good agreement with the simulation results. Overall, the findings indicate that high-entropy rare-earth oxide coatings may provide an additional radiation attenuation contribution when incorporated as layers in Inconel-718-based systems. However, since direct thermal-barrier properties such as thermal conductivity, thermal diffusivity, thermal cycling resistance, and thermal-stress behavior were not evaluated in the present work, the present study should be interpreted as a structural and radiation-transport assessment of TBC-related coating candidates rather than a direct demonstration of thermal-barrier performance.
- MakaleAçık Erişim2026Scopus SJRQ1Integrating experimental and atomistic insights into the rejuvenation of aged binder using bio-based rejuvenators
Kurban, Mustafa; Yalcin, Beyza Furtana; Yilmaz, Mehmet; Akpinar, Sinan; Kök, Baha Vural; Hekim, Seda; Özdemir, Ahmet Münir; Yalcin, Erkut; Göktaş, Fahrettin
This study integrates experimental and computational methods to evaluate the rejuvenation performance of an aged asphalt binder using two novel bio-based additives, 1T and 2T. The aged binder, sourced from reclaimed asphalt pavement (RAP), was modified with 25 wt% of each rejuvenator (denoted as 1T25 and 2T25, respectively). SARA (Saturates, Aromatics, Resins, Asphaltenes) fractionation and colloidal indices were used to assess compositional recovery. Both additives increased aromatic and resin contents while reducing asphaltenes. The 2T-modified binder achieved the highest colloidal stability (Ic = 0.29) and the most pronounced improvement in stability indicators (CI and Ic) among the tested systems. Complementary molecular dynamics (MD) simulations using the COMPASSII force field modeled the structural and thermodynamic behavior of RAP and rejuvenated systems. The 2T25 system exhibited higher density and more compact molecular packing, suggesting stronger cohesive organization and reduced free volume, whereas 1T25 showed greater molecular spacing and flexibility. RDF analysis and converged thermodynamic/structural trajectories (energy, temperature, cell length, and density stabilization) further supported rejuvenator-dependent rearrangement of packing during equilibration. Overall, MD acts as a mechanistic bridge that interprets experimental SARA/CI/Ic trends and supports design-oriented development of sustainable rejuvenators.
AtıfScopus2OpenAlex1
İncele - MakaleYalnız künye2026Scopus SJRQ1Compositionally segmented thermoelectric BiSbTe thin films on Cr/Si(100)
Yüzüak, G. Durak; Yüzüak, E.
Compositionally segmented thermoelectric (CS-TE) structures improve thermal energy conversion efficiency across large thermal gradients. However, their increased design complexity complicates performance modeling and optimization. In this study, we fabricate CS-TE BiSbTe thin films on Cr-buffered Si(100) substrates. By adopting a multidisciplinary approach, we aim to broaden the technological applicability and strategic relevance of advanced TE systems. We systematically analyze the influence of deposition pressures (5, 7, and 10 mTorr) on TE performance. Variations in working pressure alter the Bi/Sb atomic ratio in the films, while the Te content remains stable. This enables the controlled formation of CS structures. At 323 K, the power factor (PF) of TE thin films reaches 0.7, 2.4, and 7.3 mW/mK2 under 5, 7, and 10 mTorr deposition conditions, respectively. The Cr-buffered layer significantly improves the electrical conductivity of CS-TE BiSbTe films. We further engineer a p-type single-leg device integrating nanostructured Bi0.35Sb1.65Te3, Bi0.37Sb1.63Te3, and Bi0.4Sb1.60Te3 layers. These materials are optimized to achieve peak TE PF values across a wide temperature range (320 to 500 K) while ensuring robust interfacial adhesion. The CS-TE device generates 3 mW/cm2, showing a 15% improvement over single-composition samples at a 100 K temperature difference.
AtıfScopus3WoS3OpenAlex2İncele - MakaleYayıncıda açık erişim2026Scopus SJRQ1Geoeconomic dependency in selected rare-earth metals and compounds: A product-level trade network analysis
Ateş, Erdem
This study examines trade concentration, network structure, and China-centered import dependency in three selected rare-earth metal and compound categories (HS 280530, HS 284610, and HS 284690) over 2012–2024. Using bilateral trade data from the CEPII BACI database, the analysis combines concentration ratios and the Herfindahl–Hirschman Index with bilateral trade-flow networks, centrality measures, cosine-similarity networks, and country-level China Import Dependency Ratios (CID). The results reveal substantial product-level heterogeneity. Trade concentration and network structure evolve differently across the three categories, while changes in similarity-network density, community structure, and modularity are particularly pronounced for HS 284690. Trade shares and network centrality do not always move in parallel, indicating that market concentration and structural network position capture distinct dimensions of trade organization. Country-level dependency analysis further shows increasing reliance on China across all three product categories: both mean CID and the share of importing countries sourcing at least 50% of their imports from China increase between 2012 and 2024. Overall, the findings demonstrate the value of integrating concentration, network, and dependency measures to identify product-specific patterns of geoeconomic exposure in selected rare-earth metals and compounds.
- MakaleAçık Erişim2026Scopus SJRQ1Optimization, high-temperature resistance, and sulfate durability of basalt powder–blended alkali-activated slag mortars
Arslan, Furkan; Dener, Murat; Karataş, Mehmet; Benli, Ahmet
This study investigates the feasibility of using basalt powder (BP), an industrial by-product with limited reactivity, as a partial substitute for granulated blast furnace slag (GBFS) in alkali-activated systems. A comprehensive experimental program was conducted in two stages: first, a systematic optimization was performed by varying mixture parameters, including BP content, alkali dosage, activator modulus, and curing temperature to evaluate compressive strength development; second, selected binder compositions were used to produce self-compacting mortars, which were further examined for flexural strength, high-temperature resistance, and sulfate durability. The results demonstrated that moderate substitution levels (up to 20–30 % BP) could achieve satisfactory compressive strength, particularly under elevated curing temperature (60 °C) with 8 % Na2O and low to moderate modulus values. At 300 °C, mixtures with 20 % BP exhibited strength enhancement due to additional geopolymerization, demonstrating superior thermal stability compared to the control. Crucially, the incorporation of BP enhanced sulfate resistance, with the 40 % BP mixture exhibiting a slight increase in compressive strength after long-term exposure, in contrast to the marked deterioration of the GBFS-only system. Consequently, this study demonstrates that BP can be effectively utilized as a sustainable binder component, offering a practical solution for waste management while enhancing the durability of alkali-activated mortars against aggressive conditions.
AtıfScopus15WoS13OpenAlex10İncele - MakaleYayıncıda açık erişim2026Scopus SJRQ1Experimental study of an alternative precast concrete beam–column connection with embedded steel block detail
Baltaci, Alihan; Sunca, Fezayil; Şahi̇n, Muhammed Cihat; Şen, Doğa; Keçeci̇, Bedirhan; Polat, Alper; Altunişik, Ahmet Can
Precast systems have gained increasing popularity due to their advantages in construction speed, cost efficiency, and quality control. However, past earthquakes have revealed that beam–column connections are often the most vulnerable regions in precast structures, making their seismic performance a critical area of investigation. This study investigates the cyclic behavior of two full-scale precast specimens with different beam–column connection configurations: a code-compliant, Moment-Resisting Emulative-Welded Connection detail (MRCON) and an alternative Embedded Steel Block Connection detail (ESBCON). Both specimens were tested under quasi-static reversed cyclic loading to evaluate their hysteretic response, energy dissipation, stiffness degradation, residual displacements, and modal characteristics. The results demonstrate that while MRCON provided higher initial stiffness and energy dissipation, it experienced severe localized damage and rapid structural deterioration at larger drift ratios. In contrast, the embedded steel block in ESBCON successfully distributed the damage across a wider joint region, leading to a more gradual stiffness reduction and slightly lower residual displacements. Although the overall structural efficiency of ESBCON was partially hindered by the slippage of the steel block, it achieved a competitive level of moment transfer capacity compared to the conventional welded connection detail, highlighting its potential as a damage-distributing alternative once slip-mitigating modifications (surface roughening to enhance bond and embedding within the column) are implemented.
- MakaleYalnız künye2026Scopus SJRQ1Exploring the photocatalytic potential of NbTiZrW-based high-entropy alloys with Hf/Mo/Ta additions: Influence of alloying elements on their structural and photocatalytic performance
Zakir, O.; Guler, O.; Idouhli, R.; Aklalouch, M.; Dikici, B.; Khadiri, M.E.; Abouelfida, A.; Selen, V.; Şimşek, T.
In this study, the photocatalytic performance of NbTiZrW-based high-entropy alloys (HEAs) with Hf, Mo, and Ta additions was investigated. The alloys were synthesized by mechanical alloying for 120 h under a high-purity Ar atmosphere to prevent oxidation. The photocatalytic activity of the samples was evaluated based on the degradation of methylene blue (MB) under UV irradiation. Structural and chemical characterizations were performed using energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The results showed that MB removal by adsorption reached 22.96 % for NbTiZrWHf, 21.90 % for NbTiZrWTa, and 47.01 % for NbTiZrWMo. The incorporation of Mo into the NbTiZrW alloy was found to enhance electrostatic interactions between MB molecules and the alloy surface. Upon UV irradiation, the degradation efficiency increased significantly, reaching 32.84 % for NbTiZrWHf, 82.02 % for NbTiZrWTa, and 46.13 % for NbTiZrWMo within 3 h. The improved performance of the NbTiZrWHf alloy was attributed to its low particle size, which provided a larger number of active sites for photocatalytic activity, as confirmed by SEM analysis.
AtıfScopus1OpenAlex1İncele - MakaleAçık Erişim2026Scopus SJRQ1Positive body image is a pathway between nature contact and life satisfaction across 58 nations
Swami, Viren; Voracek, Martin; Stieger, Stefan; Aavik, Toivo; Ranjbar, Hamed Abdollahpour; Adebayo, Sulaiman Olanrewaju; Afhami, Reza; Ahmed, Oli; Aimé, Annie; Akel, Marwan
Time spent in nature benefits human mental and physical well-being. However, much of the variance in outcomes of nature contact remains unexplained, suggesting that new mechanistic pathways need to be considered. Here, we tested a novel conceptual model linking nature contact with life satisfaction via pathways involving positive experiences of living in and experiencing the world through the physical self. Using data from the Body Image in Nature Survey (BINS; N = 50,363), representing respondents from 58 nations and speaking 36 different languages, we find that nature contact is associated with greater self-compassion and greater perceived restoration in nature, which in turn are associated with more positive body image. In addition, more positive body image is associated with greater life satisfaction. These associations were robust to sensitivity tests, generalised to all gender identities and age groups, and held individually in almost all national groups and languages. Although replications are needed, we propose that the materialities of natural environments help to link bodily experiences to the production and experience of well-being, a process that is largely stable across national groups.
AtıfScopus4OpenAlex3
İncele - MakaleYalnız künye2026Scopus SJRQ1Engineering Ti-Zr-Hf high-entropy alloys (HEA) with rare-earth and boron additives for microstructure-controlled mixed-field radiation shielding: Fabrication, physical, structural and experimental γ-ray & fast-n shielding properties
Özkul, İskender; Güler, Ömer; Kavaz, E.; Kalay, Ece; Güler, Seval Hale; ALMisned, Ghada; Tekin, H.O.
This study investigates three newly designed Ti-Zr-Hf-based high-entropy alloys such as TiZrHfGdSm (N1), TiZrHfEr (N2), and TiZrHfGdEuB (N3), with the aim of understanding how selected rare-earth and boron additions influence microstructural evolution and dual γ-ray/fast-neutron shielding performance. All alloys were synthesized by arc melting and evaluated through thermodynamic modelling, X-ray diffraction, scanning electron microscopy with elemental mapping, and mixed-field attenuation measurements. The results show that each composition forms an HCP-type solid-solution matrix with composition-dependent lattice distortion and secondary phase formation. Among the studied systems, the Er-modified alloy N2 develops the most spatially uniform elemental distribution and demonstrates the most balanced combination of γ-ray attenuation, effective atomic number, buildup behaviour, and fast-neutron removal efficiency. N1 and N3, containing multiple rare-earth elements and, in the case of N3, boron-induced borides, exhibit distinct grain features and provide valuable insights into how multi-element additions shape photon and neutron interaction pathways. Comparative examination confirms that shielding performance in these HEAs is governed by the interplay of elemental cross sections, density, and microstructural uniformity. The findings highlight Ti-Zr-Hf-RE(B) alloys as promising platforms for multifunctional radiation-shielding materials and provide a compositional framework for future optimization in nuclear, medical, and aerospace applications.
AtıfScopus2OpenAlex2İncele - MakaleAçık Erişim2026Scopus SJRQ1Real-time photovoltaic voltage data-driven dynamic green s-box generation framework for smart grid security
Aydın, Yılmaz; Garipcan, Ali Murat; Özkaynak, Fatih
In this study, a dynamic substitution box (s-box) generation method is proposed using real-time voltage data obtained from photovoltaic (PV) panels as an environmentally sensitive entropy source. These data, affected by environmental conditions such as solar radiation and temperature, exhibit irregular and unpredictable temporal behavior, offering strong potential for cryptographic randomness generation. In this context, the 0–1 test, Kolmogorov Entropy (KE), scale-index analysis, and the National Institute of Standards and Technology (NIST) SP 800-22 test suite are applied to PV voltage data collected at 1-minute intervals, experimentally confirming their chaotic dynamics and high-entropy characteristics. Following appropriate preprocessing and nonlinear mathematical transformations, the validated data are utilized to generate 8-bit s-box structures. The cryptographic strength of the generated s-boxes is quantitatively evaluated using standard security metrics, including nonlinearity (NL), Differential Probability (DP), Linear Probability (LP), Strict Avalanche Criterion (SAC), and Bit Independence Criterion (BIC). The findings reveal that PV data can serve as a functional resource not only for energy monitoring but also for randomness-based cryptographic construction. This approach enables lightweight cryptographic solutions for resource-constrained edge devices requiring <1 KB of memory and supports context-aware data security in renewable energy infrastructures.
- MakaleYalnız künye2026Scopus SJRQ2Structural evolution and radiation shielding performance of nano-HfO2 doped lithium borotellurite glasses
Durmus, Hasan; Kilic, G.; Ilik, E.; Kavaz, E.; Güler, Ömer; Birdogan, Selcuk; ALMisned, Ghada; Tekin, H.O.
This study investigates the structural evolution and radiation shielding performance of lithium borotellurite glasses reinforced with nano-sized HfO2. We report on the competitive dynamics between the depolymerizing nature of the Li + network modifier and the high field strength Hf4+ nano-dopant, a relationship not previously explored in this matrix. Structural analysis via XRD and TEM reveals that the glass remains fully amorphous with homogeneously dispersed Hf rich nanodomains up to 4 mol%. A critical solubility threshold is identified at 6 mol%, where the precipitation of HfO2 and HfTe3O8 crystalline phases marks a distinct transition from an amorphous state to a glass-ceramic microstructure. Physical property measurements indicate that Hf4+ ions primarily occupy interstitial free volumes, leading to enhanced material density without significant network dilation. The incorporation of nano-HfO2 significantly augments gamma-ray attenuation efficiency, particularly in the low-energy region, by substantially increasing the effective atomic number and reducing the half value layer. Furthermore, the glasses exhibit robust fast-neutron shielding capabilities, outperforming conventional materials such as graphite and B4C. These findings establish nano-HfO2 as a potent structural and radiative modifier, providing a novel roadmap for designing high-density, multifunctional glass-ceramic shields for advanced nuclear applications.
AtıfScopus1OpenAlex1İncele - MakaleAçık Erişim2026Scopus SJRQ1Large-eddy simulation of flow over a square prism with moving belts
You, Rui; Fırat, Erhan
This three-dimensional (3D) numerical study investigates the feasibility of controlling the intermittently reattaching flow (IRF) by using the moving-surface boundary-layer control (MSBC) method. To this end, a fixed square prism was preferred due to its geometric simplicity and was equipped with moving belts that placed side surfaces close to the trailing edges. The effects of three dimensionless key parameters including velocity ratio (i.e., VR, the ratio of the velocity of the moving belt to the freestream velocity), length ratio (i.e., LR, the ratio of the belt length to the edge length of the square prism), and gap ratio (i.e., GR, the ratio of the spanwise distance between the neighboring belts to the edge length of the square prism) mainly on the aerodynamic characteristics were investigated using large-eddy simulation (LES). The findings suggest that the rise in VR and LR parameters leads to a proportional decrease in the time-averaged drag, 〈CD〉, attributable to their contribution to the linear momentum transfer mechanism by the moving surfaces. This mechanism, firstly, provides an additional thrust to the prism in the opposite direction of the main flow. Secondly, this mechanism increases the base pressure by stretching the shear layers from the leading edges of the prism in the streamwise direction. For LR = 0.4 and VR = 4, a 17 % reduction in 〈CD〉 was observed. Additionally, the root-mean-square (RMS) values of fluctuating drag and lift coefficients, CD-RMS and CL-RMS, have decreased by 71 % and 55 %, respectively. Conversely, the increase in the GR parameter led to an increase in the spanwise distance between each individual moving belt and a reduction in the positive effect of the linear momentum transfer mechanism on the 〈CD〉 reduction. The segmentation of moving belts along the spanwise direction also triggered the vorticity redistribution mechanism concurrently. The study also elucidated the underlying mechanisms that led to the failure of the vorticity redistribution mechanism to adequately reduce the 〈CD〉.
- MakaleYalnız künye2026Scopus SJRQ2Depositional settings and basin-fill evolution of the restricted platform system on the Intra Pontide belt during the Late Eocene-?Early Oligocene transition, western black sea region, Turkey
Us, Muhammed Sami; Tekin, Erdoğan; Akgün, Funda; Kayseri-Özer, Mine Sezgül; Varol, Baki Erdoğan
This study presents an integrated sedimentological, microfacies, and palynological analyses of the Late Eocene–?Early Oligocene (Priabonian–?Rupelian) Akçapınar Formation, exposed along the Soğanlı Stream in the Intra-Pontide Belt of the Western Black Sea region, Turkey. The formation, which overlies the evaporitic Pürçükören Formation and locally the Soğanlı Formation, records deposition in restricted shallow-marine to a lagoonal setting during a phase of significant tectonic and climatic reorganization. Detailed field mapping and measured stratigraphic sections, supported by petrographic, XRD, and SEM analyses, reveal mud-supported textures, limited faunal diversity, and thin-shelled gastropods, consistent with low-energy, brackish conditions. Palynological assemblages, identified here for the first time, refine the age constraints and document freshwater influence, whereas mineralogical data indicate alternating arid (smectite-rich) and humid (chlorite–illite-rich) intervals. Microfacies patterns (Mf1–Mf4) and lithofacies associations (Lf1–Lf8) were synthesized into three-dimensional depositional models, illustrating progressive basin restriction, episodic subaerial exposure, and evaporite precipitation. The multi-proxy approach, integrating sedimentology, microfacies, palynology, and mineralogy, refined the depositional model of the Akçapınar Formation, revealing facies heterogeneity driven by the interplay of tectonically induced basin isolation, relative sea-level fluctuations, and paleoclimatic oscillations during the Eocene–Oligocene transition, and providing new insights into the paleogeographic evolution of the northern Neo-Tethys during the final stages of its closure.
- MakaleAçık Erişim2026Scopus SJRQ1Sustainable material pathways: Utilizing biomass-derived bio-oils from agricultural wastes to restore aged asphalt binder properties
Yalcin, Beyza Furtana; Yilmaz, Mehmet; Yalcin, Erkut; Kok, Baha Vural
This study explores the valorization of agricultural biomass wastes into high-value bio-based materials by evaluating the performance of pyrolysis-derived bio-oils obtained from straw, pine cone, and olive pomace for the rejuvenation of aged asphalt binders. The effectiveness of these biomass-derived bio-oils was comparatively assessed against two commercial rejuvenators to enhance binder reusability using renewable resources. The optimum rejuvenator dosages were determined through penetration, viscosity, and dynamic shear rheometer (DSR) tests, while the associated physical and chemical modifications were investigated using FTIR, SEM-EDS, and elemental analyses. Penetration and viscosity results indicated that all rejuvenators significantly reduced binder stiffness and improved fluidity. DSR analysis indicated that increasing rejuvenator content reduced G∗/sin δ values, reflecting a decrease in binder stiffness and a softening effect of the rejuvenators, which contributes to restoring the viscoelastic balance of the aged binder. FTIR results demonstrated that biomass-derived bio-oils, particularly those from pine cone and straw, effectively reduced carbonyl (C=O) and sulfoxide (S=O) functional groups, indicating strong chemical rejuvenation. SEM-EDS analyses showed that the heterogeneous and porous morphology of bio-oils promoted improved interaction with the asphalt binder. Based on the combined results of the three experimental approaches, the optimum rejuvenator dosages were identified as 25% for commercial products, 35% for pine cone and olive pomace bio-oils, and 45% for straw bio-oil. Overall, the findings highlight that biomass-derived bio-oils produced via pyrolysis offer a sustainable and performance-effective pathway for converting agricultural residues into value-added materials, supporting circular bioenergy and biomass utilization strategies.
AtıfScopus2WoS3OpenAlex3İncele - MakaleYalnız künye2026Scopus SJRQ1Effect of Ni–Co–Cr additions on the microstructural and magnetic field–induced radiation shielding behavior of Fe–Si–B alloys
Taşgın, Yahya; Taşar, Fatih
Fe–Si–B–based amorphous metallic glasses were synthesized via powder metallurgy and arc melting, followed by alloying with 10 wt% Ni, Co, or Cr. The alloys were examined in both as-cast and heat-treated conditions to assess the combined influence of composition, thermal relaxation, and magnetic processing on their mechanical and radiation-shielding properties. Microstructural characterizations (XRD, SEM, EDS) confirmed homogeneous alloying and the presence of Fe2B, Fe0.91Si0.09, and Ni/Co/Cr-boride phases. After alloying and heat treatment, the average Vickers hardness increased from 313 HV (base Fe-Si-B) to 480 HV. All synthesized samples were exposed to a 1 T magnetic field, and their gamma-ray attenuation behavior was subsequently evaluated using a Ba-133 source (80.99–383.85 keV). After magnetic exposure, the linear attenuation coefficient (LAC) increased by ≈ 3–4% for Co-doped alloys, ≈ 2% for Ni-doped and base Fe–Si–B alloys, and < 0.5% for Cr-doped alloys, accompanied by a corresponding reduction in half-value layer (HVL) from 1.86 cm to 1.79 cm. The fast-neutron removal cross-section (ΣR) also exhibited a modest rise (≈2%). These enhancements are attributed to field-induced microstructural relaxation, including domain alignment, internal-stress reduction, and partial free-volume collapse, which subtly modify the local electron-density distribution without altering the bulk composition. Overall, the findings demonstrate that Ni–Co–Cr alloying, combined with controlled magnetic-field exposure, offers an effective and non-destructive route to enhance both the mechanical durability and γ-ray/fast-neutron shielding performance of Fe-based amorphous alloys, highlighting their potential for magnetically tunable protective coatings and advanced smart-shielding applications. In some applications, both the magnetic properties and radiation shielding properties of the material used are important. This study investigates the effects of Ni, Co, and Cr on the magnetic properties of the Fe-Si-B alloy, while also demonstrating changes in radiation shielding properties.
AtıfScopus1WoS1OpenAlex1İncele - MakaleAçık Erişim2026Scopus SJRQ1Radiation shielding performance of (SmEuYbLaEr)2TaO4 high-entropy oxide reinforced Cu matrix composites
Taşgın, Yahya; Yılmaz, Demet; Kanca, M. Sait; Kök, Mediha; Yayla, Nihal; Güler, Ömer
High-entropy oxides (HEOs) containing rare earth elements are attracting increasing interest due to their thermal stability and potential for use in radiation shielding applications. In this study, the high-entropy oxide (SmEuYbLaEr)2TaO4 was synthesized via mechanical alloying (MA) followed by calcination and incorporated into a Cu matrix at different reinforcement levels to produce volumetric composites. Structural, thermal, and microstructural analyses confirmed the successful formation of a stable HEO phase and its effective dispersion within the Cu matrix. The radiation shielding performance of the composites was experimentally evaluated over a wide range of photon energies using standard gamma-ray sources. The results showed that shielding performance depends largely on both photon energy and HEO content. Increasing the HEO concentration significantly reduced the half-value layer (HVL) while substantially increasing the mass attenuation coefficient (MAC) and radiation protection efficiency (RPE), particularly in the low- and medium-energy regions where the photoelectric effect is dominant. Among the materials studied, the Cu composite containing 20 wt% HEO exhibited the best overall shielding performance. These results demonstrate that (SmEuYbLaEr)2TaO4 is an effective additive for improving the radiation shielding capability of Cu-based composites and highlight its potential for advanced radiation protection applications.
AtıfScopus1OpenAlex1İncele - MakaleAçık Erişim2026Scopus SJRQ1Comparative assessment of individual rare-earth oxides and high-entropy rare-earth oxides reinforcements on the structural, physical, and radiation transmission properties of Inconel 718
Gül, Ali Oktay; Gökhan Albayrak, M.; Güler, Ömer; Özkul, İskender; Baykal, Duygu Sen; Almisned, Ghada; Tekin, H.O.
This study addresses a fundamental materials design question for radiation-resistant superalloys: whether rare-earth (RE) oxides are more effective when incorporated individually or when introduced collectively in a high-entropy rare-earth oxide (HE-RE2O3) form. In this context, Inconel 718 (IN718) composites were reinforced with single RE2O3 phases such as Sm2O3, Tm2O3, Er2O3, Yb2O3, Eu2O3, and La2O3 at 10 wt% and with a mechanically alloyed HE-RE2O3 phase at 1-20 wt%. Structural analyses confirmed the formation of a single-phase HE-RE2O3 with a cubic bixbyite structure and its stable integration into the IN718 matrix. Gamma-ray shielding properties were systematically evaluated over a wide photon energy range. The HE-RE2O3 reinforced samples, particularly at higher loadings, exhibited consistently higher mass and linear attenuation coefficients, elevated effective atomic numbers, reduced half-value layers, and lower buildup factors compared to both the base alloy and single-oxide reinforced counterparts, demonstrating a clear collective attenuation effect. Fast neutron removal cross sections showed more moderate variations, reflecting the dominance of neutron scattering and mass-dependent interaction mechanisms rather than atomic number effects. It can be concluded that incorporating RE elements through a high-entropy oxide configuration provides a more effective and collective compositional contribution for enhancing the radiation shielding performance of IN718 than adding RE oxides individually, offering a promising pathway for advanced nuclear and radiation-relevant applications.
AtıfScopus1OpenAlex1İncele - MakaleAçık Erişim2026Scopus SJRQ2Designing a novel FeCoNiMnCu high-entropy Alloy: Synthesis, structural evolution, magnetic behavior, and radiation shielding performance
Güler, Ömer; Şimşek, Telem; Şimşek, Tuncay; Evin, Ertan; Baykal, Duygu Sen; ALMisned, Ghada; Tekin, H.O.
In this study, a novel FeCoNiMnCu HEA was synthesized via mechanical alloying and exhibited a single-phase face-centered cubic (FCC) structure with a crystallite size of 11.7 nm and a lattice strain of 0.81 %. Magnetic characterization revealed soft ferromagnetic behavior with a saturation magnetization of 32 emu/g at 300 K, increasing to 53 emu/g at 10 K. The alloy demonstrated excellent gamma-ray attenuation, with lower half-value layer (HVL) and mean free path (MFP) values than conventional shielding materials. Notably, its fast neutron removal cross-section (ΣR = 0.1654 cm−1) outperformed standard materials such as B4C, graphite, and water in the fast neutron energy range. These findings underline the multifunctional performance of FeCoNiMnCu HEA, highlighting its strong potential for use in advanced nuclear reactor components and radiation shielding technologies.
AtıfScopus10OpenAlex6İncele - MakaleYayıncıda açık erişim2026Scopus SJRQ1Explainable AI-based deep learning architectures for hydrogen prediction in biomass syngas and photocatalysis processes: Towards a sustainable and efficient energy economy
Imak, Andaç
This study, focusing on sustainable energy production and particularly the hydrogen (H2) economy, presents an advanced artificial intelligence (AI) framework for accurately predicting H2 production from sucrose photocatalysis catalyzed by LaFeO3 (GLFO) and the H2 concentration in syngas derived from biomass conversion. The research was conducted along two main directions: (i) deep learning (DL) architectures comprising nine specially designed recurrent neural network-based models and (ii) six conventional machine learning (ML) algorithms. For both H2 production systems, the best-performing models were identified and further interpreted using explainable AI (XAI) based on SHapley Additive exPlanations (SHAP). Among all investigated algorithms, a hybrid One-dimensional Convolutional Neural Network–Bidirectional Long Short-Term Memory–Bidirectional Gated Recurrent Unit (1D-CNN–BiLSTM–BiGRU) model demonstrated the highest predictive performance. Using 10-fold cross-validation, the proposed model achieved outstanding accuracy, with an R2 value of 0.9987 ± 0.0011 for photocatalytic H2 production prediction and 0.9980 ± 0.0006 for syngas H2 concentration prediction. These results highlight the potential of the proposed framework as a precise, reliable, and practical methodological approach for modeling and optimizing complex thermochemical energy systems.
- MakaleYayıncıda açık erişim2026Scopus SJRQ1Tailoring of Dy2O3-B4C hybrid-reinforcements in Fe-Co-Ni-Cr-W High-Entropy Alloy (HEA) matrix for correlating structural, mechanical, and experimental gamma-ray transmission behaviour
Özkul, İskender; Güler, Ömer; Camgoz, Berkay; ALMisned, Ghada; Yaprak, Gunseli; Tekin, H.O.; Durmus, Hasan
This study investigates the structural, mechanical, and experimental gamma-ray attenuation properties of Fe-Co-Ni-Cr-W high-entropy alloy (HEA) composites reinforced with varying concentrations of Dy2O3 and B4C. A series of samples (S0-S4) was synthesized via vacuum arc melting to evaluate the synergistic effects of rare-earth oxide and carbide additions on a stable multi-component matrix. Thermodynamic assessments confirmed that the base alloy aligns with solid-solution formation criteria (1.61R configurational entropy, Ω = 10.33), which was experimentally validated by XRD patterns revealing a consistent FCC crystal structure across all compositions. SEM-EDS mapping further verified the successful integration of reinforcements as discrete secondary phases within the HEA matrix. Mechanical characterization showed that ceramic incorporation significantly enhances the hardness of the monolithic HEA, with the hybrid-reinforced S3 sample achieving a peak value of 628 HV. This improvement is attributed to the combined effects of oxide dispersion strengthening and microstructural refinement induced by B4C. Experimental gamma-ray transmission tests, conducted using a high-purity germanium (HPGe) detector in the 276-383 keV energy range, demonstrated that the S3 configuration provides the most efficient shielding performance, characterized by the lowest transmission factors. Interestingly, the results suggest that beyond an optimal threshold, increased reinforcement loading, as seen in S4 sample, may lead to minor performance trade-offs due to phase distribution dynamics. The findings highlight that the development of multifunctional HEA-based shields requires a delicate balance between reinforcement volume fraction and microstructural homogeneity to maximize both structural and shielding efficiency.
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