Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Gul, Muhammet(110)
- Güler, Ömer(70)
- Akkurt, Nevzat(69)
- Serdar, Osman(57)
- Yucesan, Melih(55)
- Celik, Erkan(53)
- Tekin, H.O.(52)
- ALMisned, Ghada(49)
- Bulut, Hasan(49)
- Baskonus, Haci Mehmet(48)
- Paksoy, Mehmet Yavuz(46)
- Yildirim, Numan(45)
- Kocabaş, Mehmet(41)
- Yildirim, Nuran Cikcikoglu(41)
- Zengin, Gokhan(40)
- Alataş, Mevlüt(39)
- Ince, Muharrem(38)
- Benzer, Fulya(37)
- Mete, Suleyman(34)
- Aslan, Naim(33)
- Kutlu, Banu(33)
- Yildirim, Ozal(33)
- Topal, Murat(32)
- Tanyol, Mehtap(30)
- Batan, Nevzat(28)
- Özkul, İskender(28)
- Kök, Mediha(27)
- Utku, Anıl(27)
- Can, Erkan(26)
- Danabas, Durali(26)
- Sulaiman, Tukur Abdulkadir(26)
- Ates, Mehmet(25)
- Ezer, Tülay(25)
- Guler, Omer(25)
- Kutluyer, Filiz(25)
- Say, Yakup(25)
- Serin, Faruk(25)
- Erguven, Gokhan Onder(24)
- Onat, Onur(24)
- Cakilcioglu, Ugur(23)
Yayınlar
- 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.
- MakaleYalnız künye2026Scopus SJRQ1Innovative solutions for aquaculture: detecting fish diseases with hybrid deep learning model and explainable artificial intelligence
Utku, Anıl; Barut, Abdulkadir; Alofaysan, Hind
Early identification of fish diseases is critical to maintain aquaculture and minimize its financial burden. In the diagnosis of diseases, time is critical and scientists’ experience is imperative, which makes the artificial intelligence-based models necessary. It is intended by this study to integrate deep learning with explainable artificial intelligence methods to establish an artificial intelligence-powered framework for early detection of disease in fish. In this study, we developed a hybrid artificial intelligence system designed to detect diseases in freshwater fish by analyzing skin images. The primary objectives of the system are to minimize economic losses, prevent further disease spread, and ultimately increase aquaculture productivity. For this purpose, we used a dataset consisting of images from seven different disease categories, with 250 images in each class. A new hybrid model, Residual Network-50–Vision Transformer, was developed by integrating the strengths of Residual Network-50 and Vision Transformer architectures to improve classification accuracy. The proposed model was subjected to rigorous comparison with established architectures, including Visual Geometry Group 16, Mobile Convolutional Neural Network Version 2, Efficient Neural Network–Baseline Model B0, standalone Vision Transformer, and the original Residual Network-50. The results demonstrated that Residual Network-50–Vision Transformer outperformed the model, achieving an impressive 99.14% accuracy rate. Furthermore, the study employed local interpretable model-independent explanations to explain which image features most significantly influence the model’s classification decisions, thereby enhancing the interpretability and confidence in the model’s output. The application of such advanced image processing models in combination with explainable AI techniques demonstrates significant potential to support sustainable aquaculture by reducing disease outbreaks and associated financial losses.
AtıfScopus3OpenAlex2
İncele - 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 - MakaleAçık Erişim2026Scopus SJRQ2Microstructure and Dry-Sliding Tribology of HVOF-Sprayed NiCrBSi/WC-Co Coatings on AZ91D
Gürgenç, Turan; Macit, Cevher Kürşat; Sömer, Medeni; Aksakal, Bünyamin; Ayık, Merve; Say, Yakup
High-velocity oxy-fuel (HVOF)-sprayed NiCrBSi coatings containing 0, 10, 30, and 50 wt.% WC-Co were evaluated on AZ91D magnesium alloy to determine how the discrete reinforcement level affects surface topography, phase constitution, Vickers microhardness, dry-sliding friction, mass loss, and wear-track microchemistry. As-sprayed surfaces were characterized by three-dimensional profilometry; coating cross-sections and worn surfaces by optical microscopy and SEM/EDS; phase constitution by XRD; and mechanical response by HV0.1 indentation. Dry-sliding tests were performed at 10, 30, and 50 N over 100–1000 m. Increasing WC-Co content raised Sa from 8.8 ± 0.3 to 13.0 ± 0.5 µm and Vickers microhardness from 776 ± 4 to 959 ± 5 HV0.1. XRD indicated a γ-Ni-based matrix containing boride/carbide constituents, while WC, W2C, and Co became increasingly prominent in the reinforced coatings. Boride assignments are based on diffraction evidence, whereas B and C EDS signals were treated semi-quantitatively. The 50 wt.% WC-Co coating exhibited the lowest mass loss and mean coefficient of friction at every load. Its mean friction coefficients were 0.31, 0.35, and 0.41 at 10, 30, and 50 N, corresponding to reductions of 40.1%, 38.9%, and 36.2% relative to AZ91D. At 1000 m, its mass-normalized wear rate indices were 9.0 × 10−4, 4.0 × 10−4, and 5.3 × 10−4 mg N−1 m−1, respectively. Post-wear mapping showed the largest field-scale W-Co-rich fraction in the 50 wt.% coating; however, isolated spectra containing more than 94 wt.% Mg are compatible with local coating penetration/substrate exposure and/or Mg-rich debris. The 50 wt.% composition therefore provided the best combined response among the four tested levels, while intermediate compositions are required to identify a continuous-composition optimum.
- MakaleYalnız künye2026Scopus SJRQ3New national and regional bryophyte records, 86
Wilbraham, J.; Abdirasulov, F.; Aguirre, J.; Alataş, M.; Álvaro Alba, W.R.; Aslan Ergenekon, Z.; Aswathy Raj, K.; Ayhan, E.; Batan, N.; Bednarek-Ochyra, H.
- MakaleYalnız künye2026Scopus SJRQ3Impact of ZnF2 and PbF2 on the radiation attenuation performance of the fluoride-based bismuth borate glass system
Aşkın, A.
Among the various types of glasses, fluoride-based glasses stand out due to their chemical and mechanical stability, low refractive indices, low phonon energies, and low transition temperatures. In this study, key radiation shielding parameters, including the mass attenuation coefficient (µm), half-value thickness (HVL), mean free path (MFP), transmission fraction (T), effective atomic number (Zeff), exposure build-up factors (EBF) and fast neutron removal cross-section (∑R), of the newly developed fluoride-based glass system, xZnF2—(25-x)PbF2—25Bi2O3—49.8B2O3—0.2Cr2O3 (where x is between 0, and 25 mol%), were evaluated. The data was gathered through Monte Carlo simulations, utilizing the Geant4 framework for a germanium detector and the PHY-X/PSD software. The parameters were assessed for gamma-ray energies ranging from 0.284 to 1.33 MeV across all glass samples. The results clearly show that the presence of PbF2 significantly enhances radiation shielding, owing to the high atomic number (Z) of lead. The highest µm and Zeff values were found to be highest and MFP, HVL, and T values were found to be lowest for the glass sample with the highest PbF2 content. Furthermore, the ∑R values of the glasses were observed to decrease as the PbF2 content reduced, highlighting the importance of high-Z elements in neutron absorption. Therefore, gamma and neutron shielding abilities of the studied glasses improve with the addition of PbF2 into the glass structure and glass system containing 25% mole PbF2 exhibits superior gamma and neutron shielding performance compared to shielding concrete.
AtıfScopus1WoS1İncele - MakaleYalnız künye2026Scopus SJRQ2A Bernstein polynomial estimation of the moment generating function
Susam, Selim Orhun
We study Bernstein polynomial smoothing for nonparametric estimation of the moment generating function (MGF) of a distribution supported on (Formula presented.). We prove strong consistency of the Bernstein-smoothed MGF estimator and show that, when the smoothing degree m grows sufficiently fast, it shares the same (Formula presented.) asymptotic normal distribution as the empirical MGF estimator, with variance (Formula presented.). A second-order bias–variance expansion reveals that Bernstein smoothing yields a bias of order (Formula presented.) and a variance-reduction term of order (Formula presented.). This leads to the optimal smoothing rate (Formula presented.) for pointwise mean squared error (MSE) minimization. Simulation results confirm that the Bernstein estimator is especially effective in challenging boundary-dominated settings, notably for U-shaped beta models and for larger positive t values. Overall, Bernstein polynomial smoothing provides a simple, theoretically justified, and practically effective tool for nonparametric MGF estimation on compact supports.
- MakaleAçık Erişim2026Scopus SJRQ2Which implant for Pauwels type 2 femoral neck fractures: a biomechanical study
Aydın, Oğuz; Kazez, Muhammed; Say, Yakup; Belhan, Oktay
Objective: Femoral neck fractures (FNF) in young patients are relatively rare but can lead to severe complications if not treated appro-priately. Pauwels type 2 fractures, characterized by moderate inclination, require surgical stabilization. However, no consensus exists regarding the optimal implant that provides superior biomechanical stability. This study aims to compare the biomechanical properties of 3 different fixation systems for the surgical treatment of Pauwels type 2 FNF. Methods: A total of 21 bovine femurs of similar age and size were selected and divided into 3 fixation groups: dynamic hip screw (DHS), cannulated screws (CS), and major plate (MP). Each specimen underwent axial compression testing to assess the maximum load-bearing capacity, shear force resistance, and deformation characteristics of the fixation methods. Results: The results showed that the CS group exhibited the highest shear stress resistance, followed by the DHS group, while the MP group showed significantly lower mechanical strength and elongation (P <.05). Although DHS provided substantial stability, CS demon-strated superior overall mechanical performance. In contrast, the MP system showed significantly lower resistance compared to the other 2 fixation methods. Conclusion: This biomechanical study highlights the importance of implant selection in the management of Pauwels type 2 FNF. Although previous investigations have questioned the adequacy of CS fixation in highly unstable Pauwels type 3 fractures, the results suggest that CS may be a reliable and effective option for the relatively more stable Pauwels type 2 pattern. Because the tests were performed on bovine femur models, which do not fully reflect the structural characteristics of human bone, these findings should be interpreted with caution. Further biomechanical studies using human cadaveric specimens are required to confirm the applicability of these results to clinical practice.
- MakaleAçık Erişim2026Scopus SJRQ1Effects of Melatonin Formulations on Caffeine-Evoked Cortical Activity and Pentobarbital-Induced Sleep in Mice
Sahin, Nurhan; Yabas, Mehmet; Er, Besir; Erten, Fusun; Kursun, Oznur Ece Durmaz; Cikim, Ismail Gurkan; Kaplan, Berkan; Erek, Gozde; Ozmen, Busra; Orhan, Cemal
Melatonin has chronobiotic, antioxidant, anti-inflammatory, and neuromodulatory properties, and its oral effects may vary according to formulation. This study compared conventional melatonin with a lipid-multiparticulate (LMP) formulation in two acute pharmacological mouse paradigms. Eighty-four male BALB/c mice were assigned to caffeine-evoked cortical activity or pentobarbital-induced sedative-hypnotic experiments. Mice received caffeine (7.5 mg/kg, i.p.) alone or with standard or LMP-melatonin (10 or 20 mg/kg, oral). ECoG recorded cortical electrical activity under urethane anaesthesia. In a separate cohort, latency to and duration of pentobarbital-induced loss of the righting reflex were measured. Circulating neurochemical and redox markers, as well as neurotransmitter- and inflammation-related gene and protein expression, were evaluated. Caffeine increased spike frequency and altered ECoG amplitude, together with unfavorable changes in circulating neurochemical and redox markers and in neurotransmitter receptor- and inflammation-related outcomes. Both melatonin formulations attenuated several of these changes in a dose-dependent manner, with the strongest effects generally observed in the high-dose LMP-melatonin group. Compared with conventional melatonin, LMP-melatonin produced greater modulation of ECoG activity, circulating biochemical markers, neurotransmitter-receptor expression, and IL-6 and TNF-α-related outcomes. LMP-melatonin also produced a greater reduction in the latency to and a greater prolongation of the duration of pentobarbital-induced loss of the righting reflex. LMP-melatonin produced greater formulation-dependent effects than conventional melatonin on caffeine-evoked cortical electrical activity, pentobarbital-induced sedative-hypnotic responses, and selected biochemical and molecular outcomes. However, pharmacokinetic exposure, physiological sleep stages, sleep architecture, sleep quality, and direct measures of neuronal injury were not assessed. Therefore, the findings do not directly establish enhanced bioavailability, physiological sleep promotion, or neuroprotection.
- MakaleYalnız künye2026Scopus SJRQ1Impact of hybrid Er2O3 and B4C additions on structural characteristics and experimental gamma-ray transmission behavior of Ni–Co–Fe–Cr–Mo high-entropy alloys
Özkul, İskender; Güler, Ömer; Durmus, Hasan; Camgoz, Berkay; ALMisned, G.; Yaprak, Gunseli; Tekin, H.O.
This study examines how Er2O3 and B4C additions affect the structural, microstructural, mechanical, and gamma-ray attenuation behaviour of Ni–Co–Fe–Cr–Mo high-entropy alloy composites. Five samples, labelled S0–S4, were produced by vacuum arc melting with different single and combined reinforcement contents. Thermodynamic calculations showed that the metallic matrix meets the general conditions expected for solid-solution HEA formation. XRD results indicated that an FCC-based matrix remained dominant in all samples. Reflections related to Er2O3 were identified in the Er2O3-containing compositions, while several weak secondary reflections could not be assigned with certainty because of their low intensity and peak overlap. SEM-EDS analysis confirmed the presence of Er-, O-, B-, and C-containing regions and also revealed local compositional variations within the microstructure. The reinforcement additions produced a clear increase in microhardness, with the highest value of 693 ± 51 HV0.5 obtained for the hybrid-reinforced S3 sample. Gamma-ray attenuation was measured at 276, 302, 356, and 383 keV using a high-purity germanium (HPGe) detector under narrow-beam condition. S4 showed the lowest nominal transmission factor at most energies at its actual sample thickness. However, after correcting for thickness using the Beer-Lambert relationship, S2 generally showed the highest nominal linear attenuation coefficient, while S4 gave closely comparable values at several energies. Some of the differences between samples were within the propagated counting uncertainties and were therefore interpreted with caution. Overall, the results show that the composition giving the highest hardness does not necessarily provide the strongest thickness-normalized gamma-ray attenuation. The attenuation behaviour is influenced by several factors, including reinforcement composition, sample thickness, density, phase distribution, microstructural heterogeneity, and measurement uncertainty. These findings highlight the need to optimize reinforced HEA composites according to the specific mechanical and radiation-related property being targeted.
- BildiriYalnız künye2026Scopus SJRQ4Residual-Based Evaluation of Basin and Basin Edge Effects in Türkiye: Implications for Regional Site Amplification Modeling
İçen, Abdullah; Ilki, A.; Goksu, C.; Cinar, T.; Erdik, M.
This study investigates basin, basin edge and complex topography effects in ground motion records using residuals from empirical ground motion models, to better understand regional site amplification patterns in Türkiye. Using data from the updated Strong Motion Database of Türkiye (SMD-TR) strong-motion database, we compute residuals using site amplification function and analyze their spatial distribution across regions. The clustering technique, Gaussian Mixture Models (GMM), is employed to identify regions with coherent residual patterns, primarily to capture regional site effects. After regionalization, peak amplifications within the VS30 range of 400–550 m/s are examined for potential associations with sedimentary basins or basin edge effects. The results reveal systematic amplification anomalies within the VS30 range of 400–550 m/s that are not fully captured by conventional site proxies such as VS30. Notably, residuals consistently cluster along basin edges and within deep valley regions, indicating the influence of complex three-dimensional and topographic amplification mechanisms. These observations underscore the limitations of current site characterization approaches and motivate further refinement of site response models, particularly for partially non-ergodic applications in seismic hazard analysis. This study focuses on residual-based evaluations to identify potential basin, basin-edge, and topographic effects that warrant more detailed investigation.
- MakaleAçık Erişim2026Scopus SJRQ2Synergistic Effects of Caffeine and Paclitaxel in Breast Cancer Cells: Mechanistic Insights Into NF-κB and Nrf2 Signaling
Gencoglu, Hasan; Delioglu, Saime; Nergiz, Mehmet Akif; Metin, Rumeysa; Erten, Fusun; Tokmak, Muhammed; Orhan, Cemal; Sahin, Kazim
Breast cancer remains one of the most prevalent malignancies among women. Recent studies have explored the potential of phytochemicals such as caffeine as chemosensitizing agents in enhancing the efficacy of standard chemotherapeutics like paclitaxel. This study aimed to investigate the cytotoxic, apoptotic, inflammatory, and oxidative stress-related effects of caffeine alone and in combination with paclitaxel in MCF-7 cells. Cells were treated with various concentrations of caffeine (1–100 mM), paclitaxel (0–350 µg/mL), and their combinations for 24, 48, and 72 h. Cell viability was assessed using the MTS assay, and IC₅₀ values were calculated. The expression levels of Bax, Bcl-2, NF-κB, and Nrf2 proteins were analyzed by Western blotting. Both caffeine and paclitaxel induced time- and dose-dependent reductions in MCF-7 cell viability. The combination treatment showed synergistic cytotoxicity, with significantly lower IC₅₀ values compared to single-agent treatments. Western blot analysis showed that both treatments boosted pro-apoptotic Bax and decreased anti-apoptotic Bcl-2, with slightly less effect in the combination group. NF-κB levels increased considerably in caffeine and paclitaxel groups, but were lower in the combination group compared to paclitaxel alone, suggesting a possible reduction in inflammatory signaling. Nrf2 expression increased significantly with caffeine, suggesting oxidative stress responses. In MCF-7 cells, caffeine enhanced paclitaxel's pro-apoptotic and cytotoxic actions and modified inflammation and oxidative stress pathways in a complicated, dose-dependent manner. Cytotoxicity was synergistic; however, apoptotic and stress indicators may be antagonistic. In clinical circumstances, caffeine may be an adjuvant in breast cancer treatment, however mechanistic and in vivo investigations are needed.
AtıfScopus2WoS2OpenAlex1
İncele - MakaleAçık Erişim2026Scopus SJRQ2Local Scour Process in Conduit Aerated Water Jets
Tuna, M. Cihat; Acar, Ramazan; Tunç, Mustafa
High-velocity water jets emerging from hydraulic structures cause local scouring in downstream areas, creating significant risks to structural safety. In this study, the effects of natural aeration provided through pressurized pipes on jet-induced scouring were investigated through laboratory experiments. A total of 60 experiments were conducted for different gate openings, flow rates, and downstream water levels; the scour geometries created by aerated and non-aerated jets were compared. The aeration level was defined by the dimensionless air-to-water flow ratio (Qa/Qw); maximum scour depth, scour length, scour slope angle, and jet fall distance were considered as basic evaluation parameters. The experimental results showed that increased aeration significantly reduced the maximum scour depth and scour length while moving the point of contact of the jet further upstream. While the scour depth and slope angles reached their highest values in non-aerated jets, shallower and flatter scour profiles were formed in aerated conditions. An empirical relationship predicting the maximum scour depth using experimental data has been developed and found to be in high correlation with the measured values (R2 = 0.93). The findings reveal that channel aeration is an effective method for reducing scouring and demonstrate that this approach can be considered a safe and economical alternative in the design of spillways, wastewater treatment plants, and similar hydraulic systems.
- MakaleAçık Erişim2026Scopus SJRQ1Effects of putrescine and MAP on quality, phenolics, and organic acids in strawberry tree fruits
Gundogdu, Muttalip; Yücel, Gül; Çolak, Ayşen Melda; Aglar, Erdal
Background: Strawberry tree (Arbutus unedo L.) fruits are rich in bioactive compounds but are highly perishable due to their high respiration rate and soft tissue structure, leading to rapid post-harvest quality losses. Therefore, developing sustainable strategies to maintain quality and extend shelf life is of great importance. Methods: In this study, the individual and combined effects of putrescine (1 mM) and modified atmosphere packaging (MAP) on the post-harvest quality and biochemical properties of strawberry tree fruits were investigated. Fruits harvested at full maturity were stored at 4 ± 1 °C and 90 ± 5% relative humidity for 15 days, and key quality parameters including weight loss, decay rate, respiration rate, soluble solids content, titratable acidity, vitamin C, organic acids, and phenolic compounds were periodically analyzed. Additionally, correlation analysis and principal component analysis (PCA) were performed to evaluate the relationships among variables. Results: Storage duration significantly increased weight loss and decay rate, while decreasing organic acids, vitamin C, and phenolic compounds (p ≤ 0.001). At the end of storage, weight loss reached 2.97% in control fruits, whereas it decreased to 1.14% in the Put + MAP treatment, representing a reduction of approximately 61.6%. Similarly, decay rate decreased from 6.55% (control) to 3.34% (Put + MAP). Respiration rate was also significantly suppressed, with the lowest values observed in the combined treatment. Furthermore, malic acid (1.38 vs. 0.80 g/100 g) and vitamin C (36.90 vs. 28.37 mg/100 g) were better preserved in Put + MAP-treated fruits compared to control at day 15. PCA results confirmed that Put + MAP treatment maintained the most balanced profile between quality attributes and biochemical stability. Conclusion: The combined application of putrescine and MAP exhibited a strong synergistic effect by simultaneously reducing respiration, limiting water loss and decay, and preserving bioactive compounds. This study demonstrates that integrating a natural bioregulator (putrescine) with an environmentally friendly packaging system (MAP) represents an innovative and practical approach for extending the shelf life and maintaining the nutritional quality of strawberry tree fruits. This strategy also has high potential for application in other highly perishable soft fruits.
- DüzeltmeAçık Erişim2026Scopus SJRQ3Erratum to: Sequence Analysis and Genetic Diversity of ndhF of the Chloroplast DNA (cpDNA) of Chrysophthalmum (Asteraceae) Species in Türkiye
Sevindik, Emre; Gelir, Seda Nur; Demircan, Şelale; Çiftçi, İbrahim; Paksoy, Mehmet Yavuz
The article number was incorrectly given as 30 but should have been 29.
- 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.
- MakaleAçık Erişim2026Scopus SJRQ1Geospatial evaluation of river basin small hydropower potential using AHP
Korkmaz, Meral
This study develops an integrated Geographic Information Systems (GIS) and Analytic Hierarchy Process (AHP) framework to accurately identify small hydropower plants sites that support sustainable water–energy planning. The approach is applied to the Peri River Basin in Eastern Türkiye by combining multisource remote sensing datasets with a semi-automated narrow-valley detection technique to enhance the spatial precision of site selection. Nine hydrological and physiographic criteria including stream order, rainfall, slope, geology, drainage density, elevation, land use land cover, Stream Power Index SPI and Topographic Wetness Index TWI were weighted using the AHP method to generate a five-class suitability map for small hydropower plants development. A major contribution of this study is the explicit integration of valley morphology into the conventional GIS–AHP workflow, which significantly improves the identification of hydropower favorable river segments. Results indicate that approximately 3% of the basin exhibits very high suitability, while 46% is moderately suitable for run-of-river small hydropower plants development. Model validation was performed by overlaying the suitability map with the locations of existing dams/hydropower facilities, showing that current facilities are mainly located in high-suitability zones. Separately, the workflow identified 13 newly proposed high-suitability candidate dam sites (P1–P13), selected from screened suitable dam points using narrow-valley detection criteria. By minimizing ecological disturbance and aligning with watershed-based management principles, the proposed GIS-supported multicriteria method provides a transferable and cost-effective decision-support tool for small-hydropower planning in rural and mountainous basins, offering practical contributions to sustainable resource management and the water–energy nexus.
AtıfScopus2WoS2OpenAlex4İncele - 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 SJRQ1Physical education and sports teacher candidates’ perspectives on meaning in life and smartphone addiction: a mixed-method study
Şahin, Aykut; Öner, Burak
Objective – This study aims to examine the relationship between physical education and sports (PES) teacher candidates’ levels of meaning in life and smartphone addiction, and to explore in depth how this relationship occurs through qualitative data. Methods – The study was conducted using the explanatory sequential design, one of the mixed-method designs. The quantitative part of the study included 392 PES teacher candidates studying at four universities in Turkey. Quantitative data were collected using the Meaning in Life Questionnaire and the Smartphone Addiction Scale—Short Form. Results – The findings showed a low-level, negative, and significant relationship between the presence of meaning and smartphone addiction, whereas no significant relationship was found between the search for meaning and smartphone addiction. Additionally, a low-level, positive, and significant relationship was determined between the presence of meaning and the search for meaning. In the qualitative phase of the research, semi-structured interviews were conducted to support the quantitative findings. Participants’ views indicated that sports provide individuals with meaning in life and partially balance smartphone use. Conclusion – As a result, it was determined that the concept of the search for meaning is influenced by the sports context and the sample’s characteristics, and is not a direct risk factor for smartphone addiction; rather, the search for meaning may be an indicator of adaptation or personal development, not merely a lack of a meaningful life. In contrast, it was concluded that experiencing a high level of meaningful life among PES teacher candidates has a protective effect against the risk of smartphone addiction.
- MakaleAçık Erişim2026Scopus SJRQ2Sustainable self-compacting mortars: mechanical, durability and microstructural evaluation with cement replacement materials under aggressive environmental conditions
Karabulut, Büşra; Yön, Merve Şahin; Karataş, Mehmet
The aim of this study is to assess the mechanical, physical and durability properties of environmentally friendly self-compacting mortars produced using materials containing industrial waste and natural stone. The test series were produced by substituting diatomite (D) and C class fly ash (F) with Portland cement (PC) up to 30% by weight. To evaluate the workability, mechanical and durability properties of self-compacting mortars (SCM), a total of 19 series, one of which was a reference sample, were prepared. The samples, whose mechanical properties and durability properties were investigated under sulphate attack and freeze-thaw effects, were prepared as 40 × 40 × 160 mm, and the series, whose physical properties were examined, were prepared as 50 × 50 × 50 mm. Also, SEM/EDS (Scanning Electron Microscope - Energy Dispersive X-Ray) and XRD (X-Ray Diffraction) analyses were carried out to evaluate the microstructural properties of the mixtures. When the 90-day compressive strength results were examined, it was determined that the highest decrease in compressive strength compared to the control sample occurred in the D20F10 sample with a rate of 61%, and the least decrease occurred in the D5 series with a rate of 10%. When the losses in compressive strength were evaluated after 50 freeze-thaw cycles, it was determined that there was a 100% reduction in the binary and ternary series containing D15 and D20. After six months of sulphate exposure, the D5F25 sample exhibited the most significant compressive strength reduction at roughly 40%, whereas the D15F15 series experienced the least compressive strength decline at around 5%.
