Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Bayrakdaroğlu, Serdar(4)
- Coruh, Emine(4)
- Yılmaz, Coşkun(4)
- Bjelotomić Oršulić, Olga(3)
- Ceylan, Halil İbrahim(3)
- Demir Şahin, Demet(3)
- Karabudak, Filiz(3)
- Koçak, Tevfik(3)
- Merdan, Mehmet(3)
- Akdemir, Enes(2)
- Altuğ, Tolga(2)
- Anıl, Berna(2)
- Aydın, Ahmet Serhat(2)
- Ağagündüz, Duygu(2)
- Cavusoglu, Ibrahim(2)
- Dhahbi, Wissem(2)
- Eker, Hasan(2)
- Gökrem, Levent(2)
- Kurnaz, Muammer(2)
- Melek, Mesut(2)
- Muntean, Raul Ioan(2)
- Söyler, Mehmet(2)
- Türkkan, Tuğba(2)
- Yalvac, Sefa(2)
- Yılmaz, Ali Kerim(2)
- Çam, Alper Veli(2)
- Özbek, Adem(2)
- Abdelkader, Salim Bourchid(1)
- Afacan, Kamil Bekir(1)
- Akar, Bülent(1)
- Akbulut Yıldız, Gizem(1)
- Akbulut, Cansu(1)
- Akbulut, Zeynep(1)
- Akdeniz, Ferhan(1)
- Akgun, Cagri(1)
- Akin, Meleksen(1)
- Aksüt, Yavuz Selim(1)
- Aktaş, Esra(1)
- Akyol, Pelin(1)
- Alan, Hale(1)
Yayınlar
- MakaleAçık Erişim2026Towards Greening the BRICS: Uncovering the Impact of Green Energy, Green Technology and Forest Cover on Environmental Quality
Henni, Mohamed Djafar; Ayaydın, Hasan; Akbulut Yıldız, Gizem; Orhan, Abdullah; Pilatin, Abdulmuttalip; Abdelkader, Salim Bourchid
The BRICS economies, facing the threat of climate change, face a policy challenge in transitioning from fossil-fuel-based energy systems and improving environmental quality. This necessitates urgent policy changes in the outdated energy infrastructure of BRICS countries. However, there still remains a policy gap regarding how countries in the BRICS, a group of rapidly developing economies, can grow their economies in line with the Sustainable Development Goals. The aim of our study is to investigate the impact of green energy, green technology, and forest cover on environmental quality in BRICS countries. The BRICS group of countries offers an ideal field of study for both examining the impacts of green energy, green technology, and forest areas on environmental quality in developing economies, as well as for evaluating national and global energy policies. Although numerous studies have empirically examined the relationship between environmental variables and green initiatives, the impact of green initiatives on the load capacity factor has been overlooked. These studies have generally used various econometric methods and have not included machine learning in the process. This study addresses this research gap by focusing on green energy and green technology, which are preferred for their various advantages and make significant contributions to the load capacity factor. To analyze this relationship in BRICS economies between 2000 and 2022, the Augmented Mean Group (AMG) estimator and Machine Learning algorithms were used. According to the results, strong evidence emerges of a positive relationship between green energy, the digital economy, forested area, and the load capacity factor, while a negative relationship exists between green technology, growth, and the load capacity factor. Based on robust empirical findings, renewable energy sources are a key driver of clean energy adoption and can ultimately increase the load capacity factor in BRICS economies. The results also imply that, since developments in green technological innovation in BRICS countries are still in their infancy, investments in green technologies for a sustainable environment need to be qualitatively increased.
- MakaleAçık Erişim2026Thermochemical Activation of Lightweight Slag–Perlite Alkali-Activated Slag (AAS): Overcoming Aggregate Brittleness and Sulfate Degradation
Eker, Hasan; Demir Şahin, Demet
The successful realization of a circular economy in the cement industry, coupled with a substantial reduction in carbon emissions, relies on the development of sustainable alternative binder systems. This study investigated the physicomechanical performance and sulfate resistance of composites produced by alkali activation of natural perlite and blast furnace slag. The aim of the research was to improve mechanical properties under low- and medium-alkalinity conditions (5–10 M NaOH). The samples were cured at an ambient temperature of 20 °C and then treated with heat at 60 °C. These samples were then mechanically processed and subjected to five soak–dry cycles in 5% and 10% Na2SO4 solutions. The results showed that heat treatment resulted in the formation of a dense C-A-S-H gel, increasing compressive strength approximately eightfold, from 11.64 MPa to 92 MPa. However, perlite’s porous and brittle structure limits its flexural strength to 0.27 MPa; this value is insufficient for structural applications. Under severe sulfate attack (10% Na2SO4), samples cured at ambient temperature showed a 12% mass increase in the first cycle due to solution infiltration into capillary voids. As a consequence of extensive ettringite and gypsum formation, the specimens experienced severe deterioration, resulting in a complete loss of mechanical integrity and a residual compressive strength of 0 MPa. In contrast, heat-treated samples showed limited ion diffusion due to a denser matrix and an improved aggregate interface transition zone, resulting in a 2.6% mass increase and a residual compressive strength of 5.17 MPa. Consequently, the obtained findings indicate that thermally treated alkali-activated slag–perlite composites exhibit high resistance against sodium sulfate attack and may have potential for use in specific industrial environments with high sulfate concentrations. However, the performance of these materials under more complex aggressive conditions, such as mining environments involving magnesium sulfate exposure and acidic drainage waters, should be further validated through future studies.
- MakaleAçık Erişim2026Isolation and Preliminary In Vitro Characterization of a Honey-Derived Bacillus licheniformis Isolate
Usta, Mehtap; Zengin, Kübra; Kara, Yakup; Nalçacıoğlu, Remziye; Demirbağ, Zihni; Yıldız, Oktay; Kolaylı, Sevgi
Background/Objectives: Despite its hostile physicochemical environment characterized by high osmotic pressure, acidic pH, and low water activity, honey serves as a unique ecological niche for resilient microorganisms. This study aimed to recover bacterial isolates from honeys of different botanical origins and to characterize the probiotic-associated properties of a honey-derived Bacillus licheniformis isolate. Methods: A total of 20 bacterial isolates were recovered from four honey samples, including two blossoms and two honeydew honeys. 16S rRNA gene sequence analysis showed that the recovered isolates had taxonomic assignments consistent with Bacillus licheniformis. Because 16S rRNA sequencing does not provide sufficient resolution to establish strain-level diversity or clonality, one isolate, designated Blhoney, was selected for subsequent molecular and functional characterization. Results: In vitro assays revealed that Blhoney exhibits robust tolerance to simulated gastrointestinal stress, including extreme acidity (pH 1–3), bile salts (0.3–1%), pepsin, and pancreatin, maintaining viability for up to 24 h. Phenotypic antimicrobial testing demonstrated measurable inhibition zones for erythromycin, kanamycin, chloramphenicol, ampicillin, tetracycline, gentamicin, streptomycin, and spectinomycin, whereas no measurable inhibition zones were observed for penicillin G, rifampicin, ciprofloxacin, or ceftazidime. However, MIC determination and standardized breakpoint interpretation were not performed; therefore, these findings were interpreted solely as preliminary phenotypic inhibition-zone observations. Although the isolate did not display direct antagonistic activity against the tested bacterial pathogens under experimental conditions, its persistence under the tested gastrointestinal stress conditions supports further investigation of its probiotic-associated characteristics. Conclusions: Overall, these findings indicate that the honey-derived Blhoney isolate exhibits preliminary probiotic-associated characteristics under the tested in vitro conditions. However, further strain-level genomic and safety characterization is required before its potential probiotic application can be established.
- MakaleAçık Erişim2026Prioritization of Internal and External Corporate Sustainability Dimensions: Evidence from Sustainability Auditors Using AHP
Wang, Yufu; Yeşilçelebi, Gül; Tosunoğlu Kusan, Büşra; Çam, Alper Veli; Dumitru, Mihaela
Corporate sustainability has traditionally been evaluated through environmental, social, and economic dimensions. However, increasing sustainability challenges, stakeholder expectations, and regulatory requirements indicate that sustainability extends beyond conventional performance measures and requires an integrated perspective that considers both internal organizational capabilities and external institutional conditions. This study develops an integrated internal–external sustainability framework and prioritizes sustainability dimensions from the perspective of licensed sustainability auditors in Türkiye. The proposed framework comprises governance, ethical, behavioral, cultural, environmental, social, economic, legal, and technological dimensions. The Analytic Hierarchy Process (AHP) was applied to pairwise comparison data collected from 15 licensed sustainability auditors to determine the relative importance of these dimensions. The results indicate that external sustainability dimensions received substantially higher priority (70.97%) than internal dimensions (29.03%), demonstrating that sustainability assessments are primarily shaped by environmental challenges, regulatory requirements, stakeholder expectations, technological developments, and market conditions. Among the nine corporate sustainability dimensions, environmental sustainability received the highest overall priority, followed by technological, ethical, social, economic, legal, governance, cultural, and behavioral dimensions. These findings suggest that although internal organizational capabilities remain important, corporate sustainability is predominantly influenced by external institutional and environmental factors. By proposing an integrated internal–external sustainability framework, this study extends conventional sustainability assessment approaches and contributes to the sustainability governance and assurance literature. The findings also provide practical implications for sustainability reporting, assurance, governance, and strategic decision-making by identifying the sustainability dimensions that deserve the greatest managerial and regulatory attention.
- MakaleYayıncıda açık erişim2026Chitosan-Based Colloidal Delivery Systems as Natural Carriers for Propolis: Physicochemical Characterization and Application in Walnut Sausages
Mesci Dindar, Esra; Arserim-Uçar, Dılhun Keriman; Ayna, Adnan
In this study, a chitosan-based colloidal delivery systems (CDs) was developed as a natural delivery system for phenolic compounds from propolis extracts obtained via accelerated solvent extraction (ASE) and evaluated for improving the functional properties of walnut sausages. ASE propolis extract was incorporated into a chitosan (C)-based colloidal delivery system formulated with varying concentrations of diacetyl tartaric acid ester of mono- and diglycerides (DATEM) and lecithin (L). The formulation containing 2.5% chitosan, 12% DATEM and propolis, with a particle size of 265.9 nm and a ζ-potential of +40.8 mV, was selected for further characterization and food applications. The phenolic encapsulation of CDs depended on the structural characteristics of individual phenolic compounds, with chrysin (70.51%), vanillin (65.12%), and benzoic acid (51.26%) exhibiting the highest encapsulation; CD-treated walnut sausages decreased the lipid oxidation and improved the storage stability of the walnut sausages during storage. These findings indicate that the chitosan-based colloidal delivery system is a promising carrier for improving the encapsulation of propolis phenolics in walnut sausages.
- MakaleAçık Erişim2026A Personalized Target Placement Optimization Framework for VR-Based Upper Extremity Rehabilitation
Türe, Hayati; Kalfa, Eren; Aslan, Muhammed Emin; Işık, Buket Özdemir; Topçu, Osman; Özdemir, Erhan; Sarıhan, Köksal
Featured Application: The proposed framework can be directly integrated into existing VR rehabilitation platforms to provide real-time personalized target placement for post-stroke upper extremity therapy, requiring no additional hardware beyond a standard CPU. Virtual reality (VR)-based rehabilitation is an established modality for upper extremity motor recovery; however, existing systems frequently rely on fixed, random, or therapist-tuned target placement that disregards patient-specific motor capacity and population-level priors. This study proposes a cross-patient collaborative swarm intelligence framework that derives zone-based patient profiles from real VR trajectories and augments them with a similarity-weighted cohort prior distilled from clinically similar patients’ successful trajectory clouds and zone-transition graphs. A hybrid Ant Colony Optimization (ACO)–Particle Swarm Optimization (PSO) algorithm optimizes 12 targets per session across a 27-zone ( (Formula presented.) ) workspace using a five-component fitness function encompassing reachability, zone balance, movement efficiency, heatmap-guided challenge coverage, and swarm-flow consistency. The framework was evaluated retrospectively on a single-center cohort of 36 post-stroke patients and 6373 sessions under a leakage-safe simulation protocol with 70/30 chronological splits; outcomes are model-based proxy success rates derived from each patient’s profile rather than directly observed task success. The hybrid strategy achieved a mean simulated success rate of 85.5% ± 5.5%, a 36.4% relative improvement over random placement (Wilcoxon (Formula presented.), Cohen’s (Formula presented.) ); the leakage-safe split yielded 80.1% on the held-out segment versus 61.1% for random, with no statistically significant train–test gap ( (Formula presented.) ). Ablation confirmed both PSO and ACO are individually necessary ( (Formula presented.) pp, (Formula presented.) ). Total session-start computation is 78 ms on standard CPU hardware. These findings constitute a proof-of-concept that collaborative personalized swarm optimization can substantially outperform heuristic target placement under in silico evaluation; clinical efficacy in terms of standardized motor outcome measures remains to be established in a prospective randomized controlled trial, and the findings should be replicated across centers, task modes, and a larger cohort before generalization.
- MakaleAçık Erişim2026Assessment of Atmospheric Acidifying Pollutant Trends and Their Potential Impact on Aquatic Carbon Stability in a Semi-Arid Basin: The Case of Konya
Tona, Aziz Uğur; Demir, Vahdettin
The behavior of the carbon cycle within the Land-Ocean Aquatic Continuum (LOAC) is shaped not only by aquatic processes but also by chemical interactions occurring at the atmosphere–water interface. In particular, the transport of acid rain precursors such as SO2 and NOx to surface waters via deposition can alter the water’s pH balance, thereby affecting Dissolved Inorganic Carbon (DIC) fractions and CO2 emission potential. In this study, air quality measurements from three monitoring stations (Bosna, Karatay, and Meram) in Konya province of Türkiye, along with precipitation and temperature data from a representative meteorological station for the period 2021–2023, were analyzed using the Mann–Kendall Trend Test. Additionally, seasonal pH values of groundwater were examined, and their trends were compared with those of the other variables. The findings reveal striking differences on a station basis. At the Bosna station, while NO (Z = 10.80), NO2 (Z = 9.47), and NOx (Z = 10.04) showed strong increasing trends, O3 decreased significantly (Z = −15.14). At the Karatay station, significant increasing trends were detected for CO (Z = 10.01), PM10 (Z = 8.59), SO2 (Z = 5.55), and NOx (Z = 2.44), whereas O3 exhibited a negative trend (Z = −6.54). At the Meram station, a significant decrease was observed in CO (Z = −11.63), while NO2 showed an increasing trend (Z = 3.03). Analysis of meteorological series indicated no significant trend in precipitation (Z = −0.04), but a distinct increase in temperature (Z = 2.90, p < 0.01). These findings suggest that the increasing NOx load in the Konya atmosphere accelerates O3 consumption and, combined with rising temperatures, creates a potential for change in the carbon chemistry of aquatic systems. The results demonstrate that atmospheric pollutant trends constitute an indirect but significant pressure factor on the aquatic carbon cycle in semi-arid regions and highlight the necessity of integrating atmospheric processes into carbon budget analyses within the scope of LOAC.
- MakaleAçık Erişim2026Structure-Dependent Triglyceride Protection of Freeze-Dried Lactiplantibacillus plantarum: Storage Protection Window, Lipid Oxidation, and Stress Adaptation
Sun, Zheneng; Zhang, Nan; Wang, Xiaomai; Wei, Xinyao; Ozturk, Samet; Liu, Shuxiang
Lipid-rich matrices can protect probiotics by limiting direct exposure to moisture, oxygen, and gastrointestinal stressors. However, triglycerides are chemically dynamic during storage, and differences in fatty acid structure and oxidation susceptibility may determine whether they exert protective or detrimental effects. In this study, tricaprylin, triolein, and trilinolein were evaluated as post-drying lipid storage matrices for freeze-dried Lactiplantibacillus plantarum 124 during storage at 25 °C, and 37 °C was used to accelerate lipid oxidation. Survival during storage, fatty acid chain retention, oxidation-derived products, stress tolerance, qualitative confocal imaging of membrane-integrity patterns, and transcriptomic responses were analyzed. After 30 d at 25 °C, log reductions were 0.30, 0.24, and 0.24 log10 units in the tricaprylin, triolein, and trilinolein groups, respectively, compared with 0.60 log10 units in the oil-free control, defining a common protective window. Tricaprylin showed the highest fatty acid chain retention, whereas trilinolein exhibited the greatest loss and strongest oxidative change. GC–MS detected no representative oxidation-derived products in tricaprylin, while unsaturated triglycerides generated dimethyl azelate and methyl 9-oxononanoate. Cells recovered from the protective window showed improved acid and bile tolerance, with survival increasing from 30.48% to 53.43–55.65% and from 14.85% to 22.49–27.79%, respectively. Confocal imaging further showed better-preserved membrane-integrity patterns in the triglyceride-treated groups after acid exposure. Transcriptomics indicated enhanced transport, redox, DNA-related, and cell-envelope responses, accompanied by reduced translation and growth-associated metabolism. Within the experimental conditions tested, these results suggest that triglyceride-associated attenuation of viability loss varies among triglyceride systems and across storage stages, while excessive oxidation of unsaturated triglycerides may weaken probiotic stability.
- MakaleAçık Erişim2026Topic Modeling of Occupational Accident Narratives in the Manufacturing Sector Using BERTopic: Sector-Specific Accident Pattern Analysis
Aktaş, Esra; Atmaca, Hatice Ediz
Despite technological developments and increasing awareness in the field of occupational health and safety, occupational accidents remain one of the fundamental problems that continue to have significant economic and social consequences. Particularly in the manufacturing sector, the diversity of production processes, differences in the machinery and equipment used, and the complexity of working environments cause occupational accidents to exhibit risk patterns that are both shared across sectors and specific to individual sectors. In this context, this study conducted a topic modeling analysis using the BERTopic algorithm on 1,600,000 occupational accident narratives to identify sector-specific risk patterns and error types associated with 24 different economic activities within the manufacturing sector. To improve topic modeling performance, a multilingual SentenceBERT-based embedding model and a Turkish-specific tr-MTEB embedding model were compared, and the analysis was carried out using the model that provided higher representational capacity and better topic separation performance for the occupational accident narratives. The findings show that, although the sectors differ in terms of production structure, types of machinery and equipment used, material characteristics, and working environments, occupational accidents largely cluster around similar risk mechanisms. As a result, it was determined that the BERTopic method makes the sectoral risk patterns embedded in occupational accident narratives more visible and provides an analytical basis for developing sector-specific prevention strategies in occupational safety practices.
- MakaleAçık Erişim2026Process Intensification Sonocatalytic Degradation of Malachite Green Wastewater over Hydrothermally Engineered M-ZLT@Co3O4 Nanocatalyst: Structure–Activity Relationships, Radical-Mediated Mechanism and Degradation Pathways
Kıranşan, Murat
This study reports the sonocatalytic degradation of malachite green (MG) in media using synthesized Co3O4 nanoparticles and a CTAB-modified zeolite supported Co3O4 hybrid nanocatalyst (M-ZLT@Co3O4). The catalysts were characterized by XRD, FT-IR, SEM-EDX, TEM, XRF, N2 adsorption–desorption, BET, and BJH analyses, verifying crystalline Co3O4 formation, successful immobilization on the modified zeolite support, porous architecture, morphology and elemental distribution. Under optimized conditions of 1 g L−1 catalyst dosage, 20 mg L−1 MG concentration, natural pH, and 300 W L−1 ultrasonic power, M-ZLT@Co3O4 achieved 99.31% ± 0.45% degradation within 120 min. Decreasing the MG concentration to 5 mg L−1 increased the efficiency to 99.96% ± 0.64%, confirming high activity at low pollutant loading. The degradation followed pseudo-first-order kinetics, with kapp values of 0.0042–0.0595 min−1 depending on catalyst dosage, 0.0046–0.0667 min−1 for initial MG concentration, and 0.0117–0.0620 min−1 under pH conditions. Water matrix inhibition followed distilled water (99.31%) > tap water (96.08%) > river water (88.84%) > lake water (86.90%), whereas higher ultrasonic power increased degradation from 91.98% at 200 W L−1 to 99.90% at 500 W L−1. Dye degradation followed MG (99.31%) > CR (95.78%) > BY2 (92.15%) > MV (90.24%) > AO7 (85.62%) > RB19 (82.49%). Comparative tests demonstrated performance for US/M-ZLT@Co3O4 (99.31%) compared with US/Co3O4 nanoparticles (78.48%), US/ZLT (72.86%), and US/MG alone (35.71%). The best activity was obtained at 0.8–2 g L−1 catalyst dosage and 5–20 mg L−1 MG concentration, while reusability tests showed a decrease from 99.31% to 78.82% after six cycles, indicating promising stability.
- MakaleAçık Erişim2026A Non-Newtonian Extension of Laplace–Sumudu–Elzaki Transforms
Yalcin, Numan
Classical Laplace-, Sumudu-, and Elzaki-type transforms are formulated within additive analytical frameworks and do not naturally accommodate multiplicative scaling structures arising in non-Newtonian calculus. Motivated by this limitation, this study introduces a non-Newtonian Laplace–Sumudu–Elzaki transform (NNLSET) based on logarithmic scaling mechanisms, multiplicative measures, and power-type kernels. The proposed framework is constructed by replacing the classical measure dt with the multiplicative measure (Formula presented.) and the linear scaling structure (Formula presented.) with the nonlinear scaling structure (Formula presented.). Using the logarithmic transformation (Formula presented.), a canonical kernel representation of the form (Formula presented.) is derived, establishing a correspondence between multiplicative power-type kernels and weighted exponential structures in the logarithmic domain. Within an admissible weighted function framework, several analytical properties of the transform are established, including existence, boundedness, stability, uniqueness, restricted recoverability, and a logarithmic derivative representation associated with expressions of the form (Formula presented.). A comparative analysis with the classical Laplace–Sumudu–Elzaki framework, together with illustrative differential-equation examples, a representative nonlinear MEMS oscillator, and a numerical computation, is presented. The obtained results demonstrate that the NNLSET provides a mathematically consistent framework for the analysis of multiplicative structures, logarithmic scaling phenomena, and logarithmically structured differential equations. Its applicability is further illustrated through the analysis of a representative nonlinear MEMS oscillator.
- MakaleAçık Erişim2026Citizen-Science Data Reveal Global Diversity Patterns in the Gecko Genus Hemidactylus
Kurnaz, Muammer; Berber, Ahmet Ali; Akbulut, Cansu
Understanding how species richness is distributed across space is a central goal of macroecology and biogeography. The gecko genus Hemidactylus ranks among the most speciose and broadly distributed of all squamate genera, with species spanning tropical and subtropical environments on most continents. Yet the large-scale structure of its diversity has rarely been examined at a global scale. Here we assembled georeferenced occurrence data for the genus from the Global Biodiversity Information Facility (GBIF Access data is 14 March 2026) and, following cleaning and quality control, retained 143,858 records covering 157 currently recognized species (approximately 79% of the genus) to characterize broad-scale biodiversity patterns. Our analyses addressed the latitudinal diversity gradient, the distribution of species range sizes, continental richness, spatial clustering of diversity, and regional beta diversity. Richness declined steadily from the tropics toward the poles, producing a pronounced latitudinal diversity gradient (Pearson r = −0.71, p < 0.001). A generalized additive model captured a strong non-linear association between latitude and richness (deviance explained = 98.1%), consistent with tropical regions acting as principal centers of diversity. Range-size distributions were markedly right-skewed, with the majority of species restricted to comparatively small areas; however, these estimates co-varied strongly with per-species sampling effort (r = 0.90) and warrant cautious interpretation. We found only a weak, marginally significant association between range size and latitudinal midpoint, offering little support for Rapoport’s rule in the genus. At the continental scale, Hemidactylus diversity was overwhelmingly concentrated in Afro-Asian tropical regions (Asia, 93 species; Africa, 66), whereas Europe and Oceania supported few species (four each). Spatial analyses indicated significant autocorrelation in richness (Moran’s I = 0.56, p < 0.001) and well-defined diversity hotspots in East Africa, the Indian subcontinent, and Southeast Asia, and regional beta diversity was high (Jaccard dissimilarity up to 0.97), reflecting pronounced faunal turnover among continents.
- MakaleAçık Erişim2026Enhanced Computational Efficiency in Solving Delay Fractional Partial Differential Equations Through the Yang Decomposition Method
Ali, Mustafa Ahmed; Merdan, Mehmet
This study presents the Yang Transform Adomian Decomposition Method (YTADM), a semi-analytical framework for solving one-dimensional linear and nonlinear delay fractional partial differential equations involving the Caputo fractional derivative. The proposed method combines the Yang transform with the Adomian decomposition method to construct recursive solution series while efficiently handling delayed nonlinear terms. The applicability of the proposed framework is demonstrated through several examples, including proportional-delay Burgers-type equations, and its convergence properties are analyzed. The obtained results show that YTADM yields rapidly convergent semi-analytical approximations and provides an effective framework for solving one-dimensional delay fractional partial differential equations.
- MakaleAçık Erişim2026Comparative Mechanical and Thermal Performance of Graphene- and Silver Nanoparticle-Reinforced PLA Fabricated by FDM 3D Printing
Karabudak, Filiz
The increasing demand for high-performance and multifunctional polymer materials has driven interest in improving the mechanical properties of polymer components produced through additive manufacturing. This study aims to systematically investigate and comparatively evaluate the effects of low-content nanofiller incorporation on the structural, thermal, and mechanical performance of PLA-based materials produced via fused deposition modeling (FDM), with a focus on identifying filler-dependent behavior under different loading conditions. In this study, polylactic acid (PLA) composites reinforced with 0.5 wt.% graphene (Gr) and 0.5 wt.% silver (Ag) nanoparticles, added separately, were produced using fused deposition modeling (FDM) and comparatively investigated. Each nanofiller was incorporated individually into PLA-based filaments, and standard test specimens were fabricated via 3D printing. Structural, thermal, and mechanical properties were evaluated using tensile, compressive, and three-point bending tests, along with SEM, EDS, XRD, FTIR, DSC, and TGA analyses. The results showed that pure PLA exhibited typical brittle behavior and a single-stage thermal degradation profile. The tensile strength of pure PLA was 41.93 MPa, and the flexural strength was 70.76 MPa. The addition of 0.5 wt.% graphene led to noticeable improvements, particularly in flexural properties, while only a minimal (almost negligible) increase was observed in tensile strength, with tensile strength increasing to 42.24 MPa (+0.74%) and flexural strength increasing to 110.78 MPa (+56.6%). In contrast, 0.5 wt.% Ag exhibited mixed and load-dependent mechanical behavior, with slight improvements in flexural strength but reductions in tensile and compressive properties, where tensile strength decreased to 22.13 MPa (−47.2%) while flexural strength increased to 112.06 MPa (+58.3%). Structural and thermal analyses indicated that both nanofillers did not significantly alter the PLA matrix chemically, while contributing to controlled changes in material properties primarily through physical interactions. The novelty of this work lies in the comparative evaluation of graphene and silver nanoparticle reinforcement at a fixed low loading level within FDM-processed PLA, combined with a comprehensive and correlated analysis of mechanical, structural, and thermal behavior on the same specimen sets, enabling a clearer understanding of filler-dependent performance mechanisms in additively manufactured nanocomposites. Overall, it was concluded that low-rate nanofiller additions, when properly dispersed, may lead to selective improvements in the performance of PLA-based composites depending on filler type and loading mode, and show potential for advanced engineering applications such as lightweight structural components, functional sensors, and additive-manufactured parts requiring tailored mechanical performance and multifunctionality.
- MakaleAçık Erişim2026Motion-Robust Optical Granulometry for Comminution Circuits: A Multi-Stream Temporal Deep Learning Framework
Hasozdemir, Kursat; Meral, Mert; Kahraman, Muhammet Mustafa
Accurate near-real-time granulometry is critical for optimizing energy efficiency in comminution circuits, yet standard optical monitoring systems fail under the harsh conditions of industrial mining. High conveyor velocities induce motion blur, while heavy dust loads occlude particle boundaries, leading to severe under-counting of fine fractions and an overestimation of product coarseness. This paper proposes a novel tracking framework to overcome these limitations. The method integrates a five-frame temporal rolling buffer with a multi-stream augmentation architecture that decouples motion and texture features. Experimental validation on the feed of a secondary conical crusher at an operational facility demonstrates that the proposed framework recovers significant particle data lost by baseline models, correcting the measured D80 and D50 values of the crushed material. This correction reveals a finer true load, enabling more precise closed-loop control of crusher settings and reducing unnecessary energy consumption.
- MakaleYayıncıda açık erişim2025Convergence on Kirk Iteration of Cesàro Means for Asymptotically Nonexpansive Mappings
Cona, Lale; Şimşek, Deniz
This article addresses the convergence of iteration sequences in Cesàro means for asymptotically nonexpansive mappings. Specifically, this study explores the behavior of Kirk iteration in the Cesàro means in the context of uniformly convex and reflexive Banach spaces equipped with uniformly Gâteaux differentiable norms. The focus is to determine the conditions under which the Kirk iteration sequence converges strongly or weakly to a fixed point. Finally, some examples are given in this article to demonstrate the advantages of the preferred iteration method and to verify the results obtained.
- MakaleAçık Erişim2025Motivating Green Transition: Analyzing Fuel Demands in Turkiye Amidst the Climate Crisis and Economic Impact
Coruh, Emine; Yıldız, Mehmet Selim; Urak, Faruk; Bilgic, Abdulbaki; Cengiz, Vedat
Decarbonizing the transportation sector is critical for sustainable development, particularly in rapidly urbanizing countries like Turkiye. This study analyzes fuel demand elasticities for diesel, gasoline, and LPG across 12 NUTS-1 regions of Turkiye in 2022, using a panel random effects SUR approach. The model accounts for regional variation and fuel interactions, producing robust estimates that uncover significant spatial and temporal differences in consumption patterns. Uniquely, diesel demand displays a significantly positive price elasticity, challenging the conventional assumption of inelasticity. Gasoline demand is moderately price-sensitive, while LPG appears relatively unresponsive. Strong cross-price elasticities—especially between diesel and gasoline—point to substitution effects that can inform more adaptive policy frameworks. Seasonal fluctuations and Istanbul’s outsized impact also shape national trends. These findings underscore the need for differentiated region- and fuel-specific strategies. While higher gasoline taxes may effectively reduce demand, lowering diesel and LPG use will require complementary measures such as infrastructure upgrades, behavioral incentives, and accelerated adoption of alternative fuels. The study advocates for regionally adjusted carbon pricing, removal of implicit subsidies, and targeted support for electric and hybrid vehicles. Aligning fiscal tools with actual demand behavior can enhance both the efficiency and equity of the transition to a low-carbon transportation system.
- MakaleAçık Erişim2025A Video-Based Mobile Palmprint Dataset and an Illumination-Robust Deep Learning Architecture for Unconstrained Environments
Koşmaz Sünnetci, Betül; Bingöl, Özkan; Gedikli, Eyüp; Ekinci, Murat; Doğan, Ramazan Özgür; Türk, Salih; Güngör, Nihan
Featured Application: The proposed framework facilitates secure and user-friendly biometric authentication on mobile platforms, particularly in mobile payment and access control scenarios, under unconstrained conditions. The widespread adoption of mobile devices has made secure and user-friendly biometric authentication critical. However, widely used modalities such as fingerprint and facial recognition show limited robustness under uncontrolled illumination and on heterogeneous devices. In contrast, palmprint recognition offers strong potential because of its rich textural patterns and high discriminative power. This study addresses the limitations of laboratory-based datasets that fail to capture real-world challenges. We introduce MPW-180, a novel dataset comprising videos of 180 participants recorded on their own smartphones in everyday environments. By systematically incorporating diverse illumination conditions (with and without flash) and natural free-hand movements, MPW-180 is the first dataset to adopt a bring-your-own-device paradigm, providing a realistic benchmark for evaluating generalization in mobile biometric models. In addition, we propose PalmWildNet, an SE-block-enhanced deep learning architecture trained with Triplet Loss and a cross-illumination sampling strategy. The experimental results show that conventional methods suffer over 50% performance degradation under cross-illumination conditions. In contrast, our method reduces the Equal Error Rate to 1–2% while maintaining an accuracy above 97%. These findings demonstrate that the proposed framework not only tolerates illumination variability but also learns robust illumination-invariant representations, making it well-suited for mobile biometric authentication.
- MakaleAçık Erişim2025Investigation of Tensile and Fatigue Behavior of Cr/CrN/TiCrN/TiCrCN Multilayer Films Coated on AA6063 and AZ91 Alloys by Closed-Field Unbalanced Magnetron Sputtering Process
Yeşildal, Ruhi; Sezer, Sadberk; Karabudak, Filiz
Despite the widespread use of Mg and Al alloys among light metals in the automobile and aviation industries, they have low tensile and fatigue strength. Therefore, in the present work, AZ91 Mg and AA6063 Al alloys were coated with a multilayer transition metal nitride film (Cr/CrN/TiCrN/TiCrCN) to increase fatigue and tensile strength. Films with Cr/CrN/TiCrN/TiCrCN microstructure architecture were synthesized on the surfaces of AZ91 Mg and AA6063 Al alloys using the CFUBMS (closed-field unbalanced magnetron sputtering) system, one of the PVD (physical vapor deposition) techniques. Films’ structural properties were analyzed by XRD, SEM, and EDAX, whereas mechanical properties were investigated using tensile and rotary bending fatigue testing machines. According to the SEM examination, the Cr, CrN, TiCrN, and TiCrCN multilayer nitride films on the two alloys have a columnar and dense microstructure. The XRD analysis detected Cr (211), CrN (111) and (200), TiN (111), (200) and (222), and TiCN (200) and (311) diffraction peaks. The Cr/CrN/TiCrN/TiCrCN multilayer coating increased the fatigue limit value of AZ91 by 11.22% from 70.26 MPa to 78.15 MPa. The fatigue limit value of AA6063 decreased by 9.79% from 79.71 MPa to 71.9 MPa. After coating, the tensile strength value of AZ91 increased from 137.89 MPa to 139.65 MPa, while the tensile strength of AA6063 decreased from 129.35 MPa to 118.16 MPa.
- MakaleAçık Erişim2025Intersession Robust Hybrid Brain–Computer Interface: Safe and User-Friendly Approach with LED Activation Mechanism
Aydın, Sefa; Melek, Mesut; Gökrem, Levent
This study introduces a hybrid Brain–Computer (BCI) system with a robust and secure activation mechanism between sessions, aiming to minimize the negative effects of visual stimulus-based BCI systems on user eye health. The system is based on the integration of Electroencephalography (EEG) signals and Electrooculography (EOG) artefacts, and includes an LED stimulus operating at a frequency of 7 Hz for safe activation and objects moving in different directions. While the LED functions as an activation switch that reduces visual fatigue caused by traditional visual stimuli, moving objects provide command generation depending on the user’s intention. In order to evaluate the stability of the system against physiological and psychological conditions, data were collected from 15 participants in two different sessions. The Correlation Alignment (CORAL) method was applied to the data to reduce the variance between sessions and to increase stability. A Bootstrap Aggregating algorithm was used in the classification processes, and with the CORAL method, the system accuracy rate was increased from 81.54% to 94.29%. Compared to similar BCI approaches, the proposed system offers a safe activation mechanism that effectively adapts to users’ changing cognitive states throughout the day by reducing visual fatigue, despite using a low number of EEG channels, and demonstrates its practicality and effectiveness by performing on par or superior to other systems in terms of high accuracy and robust stability.