Yazarlar
- Bulut, H. Alperen(11)
- Ertugay, Neşe(6)
- Gürses, Ahmet(6)
- Manga, Muge(6)
- Aka, Salih(5)
- Baş, Fatih İrfan(5)
- Destek, Mehmet Akif(5)
- Yavuz, Emre(5)
- Akoğuz, Harun(4)
- Akşit, Zeynep(4)
- Caglar, Bulent(4)
- Demirci, Oğuz Kürşat(4)
- Kandil, Ufuk(4)
- Kocakaplan, Nihal(4)
- Kumbasaroglu, Atila(4)
- Malkoç, Emine(4)
- Akın, Fatih(3)
- Açikyildiz, Metin(3)
- Bayata, Halim Ferit(3)
- Bayrak, Osman Ünsal(3)
- Dede, Tayfun(3)
- Doğan, Bilge(3)
- Doǧar, Çetin(3)
- El Nemr, Ahmed(3)
- Ertugay, Nese(3)
- Gençcelep, Hüseyin(3)
- Güner, Eda Keleş(3)
- Jagan, J.(3)
- Keleş, Ömer Faruk(3)
- Samui, Pijush(3)
- Turan, Ahmet İhsan(3)
- Ulusu, Hayati(3)
- Ulusu, İsmet(3)
- Yalciner, Hakan(3)
- Yavuz, Sevtap Caglar(3)
- Yılmaz, Mehmet(3)
- Çolak, Muhammed Ali(3)
- Özdemir, Agah Oktay(3)
- Şahin, Remzi(3)
- Acar, Filiz Nuran(2)
Yayınlar
- Review ArticleAçık Erişim2026Phenolic Compounds Found in Citrus Species
Akşit, Zeynep; Yenice, Fatma
Citrus fruits contain many components that are beneficial for health, including minerals, vitamins and dietary fibers. They are also the main source of many bioactive compounds with disease-preventing properties, such as flavonoids and limonoids. Flavonoids are a group of pigments found in plants and are responsible for the coloring of flowers and fruits. The richest source of flavonoids in food is fruits and vegetables. The inedible parts of citrus fruits, such as the juice and pulp of the fruit, are as rich in phenolic compounds as the edible parts of the fruit. Citrus peels and seeds are very rich in phenolic acids and flavonoids, and the peels contain more flavonoids than the seeds. The waste parts of citrus fruits, such as peels and seeds, are especially rich in flavonoids and phenolic compounds, and these compounds have important properties for health. Recycling the millions of tons of citrus waste released worldwide has significant potential in environmental and economic terms. Recovery of secondary metabolites from peels contributes to the prevention of chronic diseases as a natural antioxidant source, while reducing oxidation in foods and has the potential to extend shelf life. The phenolic and flavonoid content of citrus waste varies depending on the species, growing conditions and harvest time. The use of citrus waste in food, cosmetics and pharmaceutical industries not only reduces environmental pollution but also enables the development of value-added products in terms of health and nutrition.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2026Erzincan Ham Perlit Agregası Kullanılarak Taşıyıcı Hafif Beton Üretilebilirliğinin Araştırılması
Gül, Rüstem; Ulusu, İsmet
Maksimum agrega tane çapı 12.5 mm olan ve granülometrisi Fuller denklemine uygun olan ham perlit agregası kullanılarak taşıyıcı hafif beton üretimi üzerine bir çalışma gerçekleştirilmiştir. Bu amaçla; 150, 200, 250, 300 ve 350 kg/m³ olmak üzere beş farklı çimento dozajında ve iki farklı çökme (slump) değerinde beton numuneleri hazırlanmıştır. Taze betonun işlenebilirliğini düzenlemek amacıyla, tüm karışımlara çimento ağırlığının %1’i oranında akışkanlaştırıcı katkı ilave edilmiştir. Taze ve sertleşmiş betonun fiziksel ve mekanik özellikleri ASTM standartlarına göre belirlenmiştir. Araştırma sonuçlarına göre; perlit agregası kullanılarak 1600 ile 1900 kg/m³ birim hacim ağırlığı arasında taşıyıcı hafif beton üretiminin mümkün olduğu görülmüştür. En yüksek basınç dayanımı, 350 kg/m³ bağlayıcı miktarıyla 90 gün sonunda 35 MPa olarak elde edilmiştir. Araştırma sonuçlarına göre; betonun mekanik ve fiziksel özellikleri üzerinde en etkili iki parametre çökme değeri ile bağlayıcı miktarıdır. Üretilen betonların yarmada çekme dayanımı, basınç dayanımının %11’i olarak belirlenmiş ve su emme oranı %8 olarak tespit edilmiştir.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2026Investigation of cutting temperature, cutting force and surface roughness in turning of inconel 625 superalloy under different eco-friendly cooling/lubrication conditions
Siyambas, Yusuf
Inconel 625 superalloy is widely used in aerospace and energy industries; however, its low thermal conductivity, severe work-hardening tendency, and strong chemical affinity with cutting tools make it difficult to machine. This study systematically investigated the machinability of Inconel 625 under fifteen environmentally friendly cooling/lubrication conditions, including dry machining, high-pressure air cooling (HPAC), vortex air cooling, minimum quantity lubrication (MQL), and hybrid strategies. Machining performance was evaluated using cutting temperature, cutting force, surface roughness, tool wear, total machining cost, and carbon emission. Hybrid cooling/lubrication conditions significantly improved machining performance, reducing cutting temperature by up to 56.04%, cutting force by 11.48%, and surface roughness by 74.08%. Dry machining exhibited the lowest machining cost and carbon emission because no auxiliary cooling/lubrication equipment was employed. Grey Relational Analysis (GRA), integrating technical, economic, and environmental performance indicators, identified the HPAC (14 bar) + MQL (0.90 ml/min) condition as the optimum sustainable machining condition among the tested alternatives. SEM and EDS analyses confirmed that hybrid cooling/lubrication effectively suppressed built-up edge formation and adhesive wear. The proposed experimental framework provides a practical approach for selecting sustainable cooling/lubrication strategies for machining Inconel 625 by simultaneously considering machining performance, economic efficiency, and environmental impact. Le superalliage Inconel 625 est largement utilis & eacute; dans les secteurs de l'a & eacute;rospatiale et de l'& eacute;nergie. Cependant, sa faible conductivit & eacute; thermique, sa forte tendance & agrave; l'& eacute;crouissage et sa forte affinit & eacute; chimique avec les outils de coupe le rendent difficile & agrave; usiner. Cette & eacute;tude a examin & eacute; syst & eacute;matiquement l'usinabilit & eacute; de l'Inconel 625 sous quinze conditions de refroidissement/lubrification respectueuses de l'environnement, notamment l'usinage & agrave; sec, le refroidissement par air haute pression (HPAC), le refroidissement par air vortex, la lubrification minimale (MQL) et des strat & eacute;gies hybrides. On a & eacute;valu & eacute; les performances d'usinage en utilisant la temp & eacute;rature de coupe, la force de coupe, la rugosit & eacute; de surface, l'usure de l'outil, le co & ucirc;t total d'usinage et les & eacute;missions de carbone. Les conditions de refroidissement/lubrification hybrides ont am & eacute;lior & eacute; significativement les performances d'usinage, r & eacute;duisant la temp & eacute;rature de coupe jusqu'& agrave; 56.04%, la force de coupe de 11.48% et la rugosit & eacute; de surface de 74.08%. L'usinage & agrave; sec pr & eacute;sentait le co & ucirc;t d'usinage et les & eacute;missions de carbone les plus faibles, puisque l'on a utilis & eacute; aucun & eacute;quipement auxiliaire de refroidissement/lubrification. L'analyse relationnelle grise (GRA), int & eacute;grant des indicateurs de performance techniques, & eacute;conomiques et environnementaux, a identifi & eacute; la condition HPAC (14 bars) + MQL (0.90 ml/min) comme la condition d'usinage durable optimale parmi les choix & eacute;valu & eacute;s. Les analyses de MEB et d'EDS ont confirm & eacute; que le refroidissement/lubrification hybride supprimait efficacement la formation de bordures renforc & eacute;es et l'usure adh & eacute;sive. Le cadre exp & eacute;rimental propos & eacute; offre une approche pratique pour la s & eacute;lection de strat & eacute;gies de refroidissement/lubrification durables pour l'usinage de l'Inconel 625, en consid & eacute;rant simultan & eacute;ment les performances d'usinage, l'efficacit & eacute; & eacute;conomique et l'impact environnemental.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2026Removal of Malachite Green from Aqueous Solutions by Using Bi4V2O11 Nanosheet
Yavuz, Emre; Dundar, Ozan Ali; Yavuz, Sevtap Caglar; Yilmaz, Erkan; Ozdokur, Kemal Volkan; Cirak, Burcu Bozkurt; Caglar, Bulent; Cirak, Cagri; Arar, Özgür
Introduction: Transition metal oxides are highly effective for dye removal due to their adaptable surface chemistry, availability, and robust mechanical and thermal properties. Among them, Bi4V2O11 nanosheets offer potential due to their morphology and high surface area. To synthesize Bi4V2O11 nanosheets and evaluate their performance in removing malachite green, focusing on the impact of adsorbent amount, contact time, and interfering ions on dye removal efficiency. This study aims to evaluate the performance of Bi4V2O11 nanosheets in removing malachite green dye from aqueous solutions and to examine the effects of adsorbent dosage, contact time, and the presence of coexisting ions on the sorption process. Methods: Bi4V2O11 nanosheets were synthesized and used to remove the malachite green dye. Batch experiments were conducted to study the effects of adsorbent dose, contact time, and coexisting ions (Na+, Ca2+, and tannic acid). Equilibrium data were fitted to the Langmuir isotherm model to determine the maximum sorption capacity. Results: Malachite green sorption using Bi4V2O11 nanosheets reached equilibrium within 240 minutes, demonstrating efficient dye removal under the tested conditions. The sorption process conformed to the Langmuir isotherm model, indicating monolayer adsorption with a maximum capacity of 47.27 mg/g. While the presence of Na+ and tannic acid had negligible effects on dye removal efficiency, the coexistence of Ca2+ significantly reduced the removal efficiency from 95% to 58%, highlighting the potential impact of divalent ions on the adsorption process. Discussion: Bi4V2O11 nanosheets are effective adsorbents for malachite green removal, demonstrating high sorption capacity and resilience to Na+ and tannic acid interference. However, the presence of Ca2+ significantly reduces removal efficiency, highlighting the need for further optimization in practical applications. Conclusion: Bi4V2O11 nanosheets offer high sorption capacity and structural stability, environment friendly synthesis procedure, making them feasible for small-scale or pre-treatment applications. 2026, Bentham Science Publishers
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2026Monitoring of the compatibility between the radon gas emanation and the self-compacting concrete properties using different mineral admixture
Bulut, H. Alperen; Şahin, Remzi
The relationships between radon gas emanation, permeability, and compressive strength in Self-Compacting Concretes containing different ratios of fly ash, silica fume, and ground granulated blast furnace slag (respectively of 5%, 12.5%, and 20%) were comprehensively investigated. Permeability tests were performed according to both traditional (sorptivity) and indirect (rapid chloride ion permeability) methods, and the relationship between Brunauer-Emmett-Teller analyses and radon concentration of self-compacting concretes was also analysed. Based on 120-day data, the optimum ratios for the combination of high compressive strength and low Average Radon Activity Concentration were determined to be 5% fly ash and 20% silica fume. As the sorptivity coefficients of self-compacting concretes containing silica fume and ground granulated blast furnace slag increased, the Average Radon Activity Concentration also increased. This later decreased with the increase in the sorptivity coefficient of the mixtures. The rapid chloride ion permeability of the control, fly ash-, ground granulated blast furnace slag-, and silica fume-added concrete was found to be 6077 Coulomb, 2989 Coulomb, 1668 Coulomb, and 1137 Coulomb, respectively. The relationship between rapid chloride ion permeability and Average Radon Activity Concentration of the mixtures varied depending on the type of mineral additive. The 90-day sample containing 12.5% fly ash had the highest Brunauer-Emmett-Teller surface area (33.01 m2/g) and cumulative pore volume (0.071 cm3/g) values. This study provides a novel perspective by simultaneously examining the relationships between radon activity concentration, permeability properties, and compressive strength of self-compacting concretes produced with different mineral additives. Unlike previous studies, this work establishes direct correlations between radon emanation and both sorptivity and chloride ion permeability, identifying silica fume and ground granulated blast furnace slag as effective additives for achieving low-permeability and low-radiation concrete. These findings offer a new approach for developing durable and radiologically safer self-compacting concrete mixtures.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2026Multidimensional Sustainability Performance Measurement in the Banking Industry: A Data-Driven Grey Decision-Support Framework
Işık, Özcan; Shabir, Mohsin; Oğuz, Alparslan; Alkan, Okan
Given the critical role that banks play in sustainable development through their financial intermediation and capital allocation functions, assessing their sustainability performance has become an increasingly important research issue. In response, this research introduces a data-driven grey decision-support framework for assessing multidimensional sustainability performance in the banking industry. Sustainability indicators are systematically identified through text-mining-based content analysis of banks' sustainability reports and annual activity reports. The empirical analysis covers nine banks continuously included in the BIST Sustainability Index over the 2020–2024 period. To reflect temporal variability in sustainability disclosures, the assessment is formulated under grey interval numbers. Within this decision-support framework, Grey LODECI is employed to identify criterion importance, while Grey SWI is utilized to rank bank performance in terms of sustainability. This manuscript also offers useful implications for bank managers, regulators, investors, and sustainability rating agencies by supporting more comprehensive sustainability benchmarking and more informed strategic and regulatory decision-making.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2026Assessment of Low-Temperature Fracture Behavior in Bituminous Mixtures Incorporating Sustainable Waste Additives: SCB Testing and Finite Element Analysis
Keleş, Ömer Faruk; Çolak, Muhammed Ali; Demiriz, Ahmet Oğuz; Baş, Fatih İrfan
In this study, the combined effect of waste lubricating oil (WLO) and waste pine branch ash (WPBA) was investigated to improve the low-temperature fracture behavior of asphalt mixtures. To investigate the low-temperature fracture behavior of the mixtures containing 2%–6% WLO and 3%–12% WPBA, the semi-circular bending (SCB) test was conducted at −15 °C, and the experimental results were analyzed using a statistical approach. Fracture toughness (K(IC)), total fracture energy (GF) and its pre-peak and post-peak components, crack resistance index (CRI), flexibility index (FI), and toughness index (TI) were determined. The findings indicate that the optimal combination depends on the fracture parameter under consideration. The best fracture toughness results, K(IC) = 24.96 MPa·mm0.5, indicating increased resistance to crack initiation, was obtained at 4% WLO and 12% WPBA content. On the other hand, the best fracture energy results, GF = 1.202 N/mm, reflecting an increase in energy dissipation during crack propagation, was obtained at 4% WLO and 9% WPBA content. The highest FI, CRI, and TI values were obtained with 6% WLO and 9% WPBA, corresponding to increases of approximately 66%, 69%, and 16%, respectively, compared with the reference mixture. This resulted in greater crack-initiation resistance, improved post-peak deformation capacity, and higher energy-dissipation capacity, although the greater WLO content led to a decrease in structural integrity. When the results are evaluated overall, it is understood that the use of WLO in the mixtures increases deformation capacity, while the use of WPBA controls crack propagation through its hardening and filling effects. In mixtures containing 4% WLO and 9%–12% WPBA, a balanced behavior was achieved in terms of crack initiation, crack propagation, and stiffness under low-temperature conditions.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2026Functional Lightweight Concrete Systems for Sustainable Load-Bearing Applications: Experimental Assessment of Perlite-Modified Reinforced Concrete Beams
Polat, Melih Sakir; Turan, Ahmet İhsan; Kucuk, Mesut; Kumbasaroglu, Atila; Yalciner, Hakan; Ayaz, Yasar
The increasing demand for sustainable structural materials in the construction industry has intensified the need to develop high-performance and environmentally efficient reinforced concrete systems. In this context, the incorporation of functional material-enhanced concrete systems, including raw lightweight aggregates such as perlite, offers a promising pathway for reducing environmental impact while maintaining adequate structural performance. This study experimentally investigates the flexural behavior of reinforced concrete (RC) beams incorporating raw perlite aggregates within a functional material-enhanced structural framework. A total of four RC beams with identical geometry and reinforcement details were produced, including perlite aggregate beams (P25 and P40) and conventional aggregate beams (C25 and C40), corresponding to compressive strength classes of 25 MPa and 40 MPa. All specimens were tested under monotonic flexural loading conditions. The structural response was evaluated in terms of load–displacement behavior, stiffness degradation, ductility, energy dissipation capacity, moment–curvature response, and failure modes. The results indicate that perlite aggregate beams exhibit reduced stiffness and energy dissipation capacity compared to conventional counterparts at comparable mixture-average compressive-strength levels. However, the high-strength perlite beam (P40) demonstrated comparable flexural capacity and ductility to the normal-strength conventional beam (C25), highlighting its potential for sustainable structural applications. Furthermore, a building-scale environmental assessment based on a representative three-story reinforced concrete structure demonstrates that the use of raw perlite aggregates significantly reduces energy consumption, CO2-equivalent emissions, and water usage. From a functional materials perspective, the findings provide a basis for the future development of multifunctional load-bearing concrete systems, where lightweight aggregate substrates can be combined with protective or performance-enhancing coating technologies to achieve improved durability, environmental resistance, and structural efficiency. This integration could further enhance durability and long-term structural performance in load-bearing applications.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2026A novel multi-objective optimization model for the time–cost–environmental impact trade-off in construction projects using a strength Pareto-based whale optimization algorithm
Yılmaz, Mehmet; Dede, Tayfun
The construction industry, a key contributor to global economic development, significantly impacts environmental pollution through greenhouse gas emissions. While conventional construction project management prioritizes cost and time reduction, environmental considerations are increasingly critical. This study addresses the time-cost-environmental impact trade-off problem by introducing a strength Pareto-based whale optimization algorithm (SP2WOA). The algorithm enhances solution diversity and achieves well-distributed Pareto fronts by integrating strength Pareto operators with the whale optimization algorithm. Its effectiveness is demonstrated through three diverse construction projects. Compared to previous algorithms (non-dominated sorting genetic algorithm-II, opposition-based multi-objective differential evolution, golden ratio-based opposite teaching-learning-based optimization and enhanced multi-objective grasshopper optimization algorithm), SP2WOA achieves superior balances between time, cost and environmental impact, using 33-60% fewer function evaluations. Statistical analysis using Wilcoxon rank tests confirms SP2WOA's superiority in both hypervolume and spread metrics. The results demonstrate that SP2WOA offers a valuable tool for sustainable construction project management.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2026THE RELATIONSHIP BETWEEN EXTERNAL DEBT AND ENVIRONMENTAL QUALITY IN TÜRKIYE: A FRACTIONAL FREQUENCY FOURIER ARDL BOUNDS TEST APPROACH
Akın, Fatih
As efforts to achieve global sustainability goals intensify, it is increasingly important to understand the environmental consequences of countries’economic policies, particularly the impact o fmacroeconomic variables such as external debt. This study analyses the impact of Türkiye’s external debt on environmental sustainability for 1970–2023 using the Fractional Frequency Fourier Autoregressive Distributed Lag (FFF-ARDL) method. Moreover, the variables of economic growth, renewable energy consumption (REN), and non-renewable energy (NREN) consumption were included in the model, and the Environmental Kuznets Curve (EKC) hypothesis was tested. Carbon dioxide (CO2) emissions were used as a proxy for environmental sustainability. The long-run coefficient findings indicate that increases in external debt reduce CO2 emissions, while economic growth initially increases emissions but then declines after a certain income threshold, confirming the EKC hypothesis. Moreover, REN energy consumption decreases CO2 emissions, whereas NREN energy consumption increases them. The Fourier Toda-Yamamoto test results indicate unidirectional causality running from CO2 emissions, REN, and external debt to NREN consumption. There is also unidirectional causality running from economic growth, REN, and NREN consumption to external debt. These findings suggest that Türkiye’s external debt management and the transition toward REN sources are crucial for reducing CO2 emissions.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2026Chemical Characterization and Antimicrobial Activity of Pyrolysis Liquids from Walnut Residue
Koc, Ibrahim; Ogun, Erdal; Geven, Fatmagul; Guney, Kerim; Yildiz, Faruk; Kaya, Ozkan
Pyrolysis liquid (PL) derived from biomass pyrolysis exhibits biopesticidal properties and represents a promising value-added product within the sustainable circular economy framework. However, knowledge about the antimicrobial potential of PLs produced from walnut residue at different pyrolysis temperatures remains limited. We investigated the chemical composition and antimicrobial activity of PLs obtained from agricultural walnut residue (Juglans regia L.) against selected plant pathogenic bacteria and fungi. PLs were produced at four temperature ranges: 200–300 °C (W-1), 300–400 °C (W-2), 400–500 °C (W-3), and 500–600 °C (W-4). Chemical characterization was performed using Gas chromatography–mass spectrometry (GC-MS), High-performance liquid chromatography (HPLC), and Inductively coupled plasma optical emission spectrometry (ICP-OES), with determination of total phenolic and flavonoid contents. Pyrolysis temperature significantly influenced the chemical profile and bioactive compound content of the PLs, with W-4 showing the highest total phenolic and flavonoid levels. Heavy metal analysis indicated minimal contamination in all samples. Antibacterial activity was observed in stock solutions, whereas diluted applications showed limited effects. The W-4 fraction showed the strongest antibacterial activity and exhibited MIC values of 12.50 µL/mL against Clavibacter michiganensis subsp. michiganensis, Xanthomonas euvesicatoria, and Pseudomonas syringae pv. syringae, and 25.00 µL/mL against Erwinia amylovora. Antifungal activity differed markedly across temperature ranges, with W-3 and W-4 displaying superior activity against Fusarium oxysporum and Verticillium dahliae, achieving complete mycelial growth inhibition at 5%, compared to 10% for W-2 and 20% for W-1. Positive controls confirmed assay validity (ciprofloxacin for antibacterial assays and cycloheximide for antifungal assays), whereas negative controls showed no inhibitory effect. Overall, higher pyrolysis temperatures, particularly 400–600 °C, enhanced the antimicrobial potential of walnut residue-derived PLs, supporting their possible use as bio-based antifungal agents for sustainable crop protection.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2026ZnBi2O4/Ag2WO4 nanocomposite for efficient photocatalytic removal of dye and pharmaceutical pollutants
Yavuz, Sevtap Caglar; Emul, Zeynep; Icer, Fatih; Yavuz, Emre; Ozdokur, Volkan Kemal; Cirak, Burcu Bozkurt
This paper targets to synthesize a nano-composite with high photocatalytic performance and research the possibility of utilizing it for dye and drug removal from wastewater. Herein, ZnBi2O4/Ag2WO4 nanocomposite photocatalyst was successfully synthesized via two step hydrothermal/precipitation method. The photocatalytic activity of the synthesized nanocomposite was evaluated by its effect on the degradation of methylene blue dye and sulfamerazine drug under UV light. The results revealed that the ZnBi2O4/Ag2WO4 nanocomposite achieved a significantly higher photocatalytic efficiency (96% degradation of methylene blue in 1 h) compared to ZnBi2O4 (41%) and Ag2WO4 (76%) within only 60 min. The exceptional photocatalytic degradation efficiency of the ZnBi2O4/Ag2WO4 nanocomposite against methylene blue and sulfamerazine can be attributed to the effects of reduced charge carrier recombination resulting from the synergistic effect of surface adsorption-photocatalytic degradation interaction of ZnBi2O4 and Ag2WO4.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2026Experimental evaluation of reinforced concrete columns produced with natural perlite aggregates under cyclic loading
Atlı, Sefa; Yalciner, Hakan; Kumbasaroglu, Atila; Ayaz, Yaşar; Turan, Ahmet İhsan; Bulut, H. Alperen; Naimi, Sepanta
A total of four reinforced concrete (RC) columns were tested to compare the structural capacities of RC columns produced by natural perlite aggregates and conventional concrete. The structural performance of the RC columns made from natural perlite aggregates was compared to conventional RC columns regarding the same concrete strength levels, sectional properties, and reinforcement layouts of conventional RC columns. The RC columns were tested under a combined constant axial load ratio of 30% with cyclic loading for two concrete strength levels, namely, 25 and 40 MPa. Load–displacement curves, energy absorption capacities, stiffness degradation, the moment-curvature relationship, the plastic hinge mechanism, and the ductility index were experimentally obtained at two different concrete types along with the measured stress–strain properties of the conventional and perlite concrete. The test results showed that the construction of the RC columns using only perlite may become possible in the future by providing an adequate concrete stress–strain capacity, which will be improved. Additionally, the use of natural perlite aggregates can contribute to sustainable construction practices by reducing the reliance on conventional aggregates.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2026The effect of elevated temperature on the mechanical properties of concrete produced with raw perlite aggregate
Ozturk, Akif Berke; Turan, Ahmet İhsan; Kumbasaroglu, Atila; Yalciner, Hakan; Ayaz, Yaşar
Deterioration caused by elevated temperatures in the micro- and macrostructure of concrete can lead to significant reductions in its mechanical performance, making it crucial to assess the residual behavior of concrete elements after thermal exposure. This study experimentally investigates the effects of elevated temperatures (25 °C, 200 °C, 400 °C, and 600 °C) on cubic and prismatic specimens produced with two different aggregate types (raw perlite aggregate and conventional coarse aggregate) across four mixtures (C25, C40, P25, and P40). Destructive (compressive and flexural strength) and non-destructive (ultrasonic pulse velocity, scanning electron microscopy) tests were conducted before and after thermal loading. Increasing the temperature to 600 °C reduced the compressive strength of conventional mixtures by 34.91 % (C25) and 41.79 % (C40), whereas perlite-based concretes exhibited significantly lower reductions of 9.91 % (P25) and 12.80 % (P40). Mass loss remained negligible (<2 %) up to 200 °C, increased to 4–6 % for conventional mixtures and 6–11 % for perlite-based mixtures at 400 °C, and reached 25–40 % and nearly 47 %, respectively, at 600 °C. UPV results revealed a substantial degradation in internal integrity at high temperatures, with decreases of 49–60 % in conventional concretes and only 16–17 % in perlite-based mixtures at 600 °C. Although the flexural strength of P25 and P40 was initially lower at 25 °C, their post-heating performance became comparable to conventional mixtures, showing similar residual flexural behavior at elevated temperatures. SEM observations further confirmed that perlite-based concretes exhibited fewer microcracks and reduced matrix deterioration compared to conventional mixtures. Overall, the findings clearly demonstrate that raw perlite aggregate significantly enhances the thermal resistance, internal stability, and residual durability of concrete, making it a promising sustainable alternative for structures exposed to elevated temperature environments.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2026Waste Management Strategies for Environmental Wellbeing: Exploring the Roles of Environmental Regulations and Green Finance in Reducing Carbon Intensity
Caglar, Abdullah Emre; Destek, Mehmet Akif; Demirdag, Ismail; Manga, Muge; Aydın, Sercan
Rising industrial activity, urban expansion, and economic growth continue to intensify waste generation and greenhouse gas emissions, placing growing pressure on environmental sustainability. In this setting, reducing the carbon intensity of electricity generation has become a key policy priority, particularly in advanced economies pursuing long-term decarbonization. Grounded in Ecological Modernization Theory and the Porter Hypothesis, this study examines the effects of waste management, environmental regulations, green finance, and economic growth on the carbon intensity of electricity generation in the G-6 economies, namely France, Germany, Italy, Japan, the United Kingdom, and the United States. This article contributes to the literature in two ways. First, the paper ensures a focused assessment of the direct roles of waste management, environmental regulations, and green finance in shaping carbon intensity in advanced economies. Second, it investigates whether the effectiveness of green finance depends on the stringency of environmental regulation. Utilizing panel data of the 2000–2020 period, drawn from Our World in Data, the World Development Indicators, the OECD, and the IEA, the analysis employs the CS-ARDL and AMG estimators to address issues of cross-sectional dependence and heterogeneity. The findings show that waste management, environmental regulations, and economic growth reduce carbon intensity in the long run, whereas green finance on its own does not have a statistically significant effect. However, green finance becomes effective when combined with stricter environmental regulations. These findings underscore the importance of coordinated policy design and offer practical insights to advance progress toward SDGs 11, 12, and 13.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2026A comprehensive approach for lightweight polymer concrete production: Determination of the effect of resin and perlite types on high temperature, freeze-thaw behavior and damage mechanisms of polymer concrete
Gülnahar, Bedirhan İhsan; Alperen Bulut, H.
The purpose of this study is to examine the durability performance of lightweight polymer concrete produced using natural and expanded perlite aggregates under extreme conditions. Within this scope, the effects of perlite aggregates on both the macroscopic performance and microstructural properties of polyester and vinylester resin polymer concrete matrices have been evaluated in an original manner using a comprehensive and comparative approach. In the experimental study, 5% and 10% by volume of quartz aggregates were replaced with natural and expanded perlite. The durability performance of the produced polymer concrete has been tested under extreme environmental conditions, including exposure to high temperatures (50°C, 100°C, 150°C, and 200°C) and freeze-thaw cycles (up to 300 cycles). Additionally, microstructural analyses were performed using weight loss, compressive strength loss, visual evaluations, and scanning electron microscopy (SEM) to investigate the damage mechanisms. The results obtained show that significant changes occur in the durability performance of polymer concrete under extreme conditions, depending on the type of perlite and the ratio of use. Natural perlite aggregates have demonstrated higher durability and minimal performance loss by providing better adhesion with both resin types. However, the high porosity of expanded perlite increased the permeability of the matrix and caused significant deterioration. Vinylester resin polymer concrete has been found to exhibit superior resistance to both high temperatures and freeze-thaw cycles compared to polyester resin concrete. Among all mixtures, vinylester resin polymer concrete containing 5% natural perlite showed the most stable internal structure with the lowest durability losses. These results reveal that natural perlite, a local and sustainable lightweight aggregate, offers an important alternative for the low-carbon building material concept by enhancing the environmental performance of polymer concrete.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2026Valorization of fruit pits from Prunus laurocerasus and Prunus cerasifera as agro-food byproducts: Bioactive properties and safety assessment for potential food additive applications
Güven, Zühal Bayrakçeken; Karadayı, Mehmet; Yilmaz, Mustafa Abdullah; Tugay, Osman; Cakir, Oguz
BACKGROUND: Food additives are widely used to extend the shelf life of foods and maintain their quality. In this study, the potential of Prunus laurocerasus and Prunus cerasifera fruit pits (endocarp and seed) as food additives was investigated in terms of cytotoxicity, antigenotoxicity, antioxidant activity, enzymatic anti-browning, and urease enzyme inhibition, and their phytochemical contents were comprehensively analyzed. RESULTS: While the extracts showed low cytotoxicity against the healthy L929 cell line, they exhibited a concentration-dependent increase in selective cytotoxicity against A549, CaCo-2, Hep3B, MCF-7, and PC-3 cells. Furthermore, the genotoxic safety of the extracts was assessed in both prokaryotic and eukaryotic model test systems. The extracts showed no cytogenotoxic or mutagenic effects in the Allium cepa and Ames/Salmonella assays. P. cerasifera endocarp ethyl acetate extract exhibited the highest antioxidant activity (DPPH, CUPRAC, and TEAC: 576.24, 402.42, and 680.14 mg Trolox g−1 extract, respectively) and strong enzyme inhibition, with tyrosinase (IC50: 10.46 ± 1.48 μg mL−1) nearly comparable to kojic acid and potent urease inhibition (IC50: 28.60 ± 2.08 μg mL−1). Phytochemical analysis of the extracts was performed using liquid chromatography–tandem mass spectrometry, with epicatechin (10.722 mg g−1 extract) detected in the highest amount in the endocarp of P. laurocerasus and quinic acid (11.679 mg g−1 extract) detected in the endocarp of P. cerasifera. CONCLUSION: Overall, according to the conducted cytotoxicity and genotoxicity assays, P. laurocerasus and P. cerasifera fruit pits were found to be safe, rich in bioactive phytochemicals, and exhibited strong antioxidant and enzyme inhibitory activities, highlighting their potential as sustainable functional ingredients or natural food additives.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2026Investigation of production and performance evaluation of high-strength lightweight concrete (HSLWC) produced with regional volcanic aggregates (RVA)
Ulusu, İsmet; Ulusu, Hayati; Gül, Rüstem
This study investigates the feasibility of producing high-strength lightweight concrete using regional volcanic aggregate (RVA) and examines the performance of the produced concrete. Various mix designs conforming to ASTM and TS EN standards were applied to achieve the targeted strength and density. The study also investigated the effect of water/cement ratio (W/C) and cement content on the mechanical and physical properties of high-strength lightweight concrete. Experimental tests such as compressive strength, tensile strength, density, water absorption, and elastic modulus were conducted to determine the effect of cement content and lightweight aggregate on the overall behavior of the concrete. To ensure adequate workability, superplasticizer was added to all mixes at a rate of 1.5% of the cement weight. The slump values of fresh concrete met modern requirements for good workability, pumpability, and high strength. The results showed that, provided a superplasticizer is used, high-strength concrete with a density range of 1830 to 1915 kg/m³ can be produced using 450 kg/m³ of cement. The results show that the porous structure and pozzolanic properties of RVA significantly increase the mechanical strength of concrete and, thanks to its porous structure, reduce its unit weight by 20–25%. The highest compressive strength recorded within 90 days for a mixture containing 650 kg/m³ of cement was 87 MPa. It was concluded that the W/C ratio and cement content have a significant effect on the mechanical and physical properties of these concretes.
RDL Kalıcı Kaydıİncele - Conference ObjectYalnız künye2026Application of Arithmetic Optimization Algorithm (AOA) for Time–Cost–Quality–Environmental Impact Optimization in Construction Projects
Yılmaz, Mehmet; Dede, Tayfun; Rao, Ravipudi Venkata; Rao, R.V.; Taler, J.; Taler, D.
This study aims to investigate the relationship between time, cost, quality, and environmental impact in construction projects using arithmetic optimization algorithm. Project managers have prioritized time and cost concepts in traditional project planning. It is seen that other factors affecting the success of the project are ignored. However, with the impact of technological and sociocultural changes, awareness of sustainability and environmental factors has increased. For this reason, there are studies showing that environmental impact is taken into account at least as much as time, cost, and quality in project management. Therefore, this study evaluates the performance of the arithmetic optimization algorithm (AOA) on the many-objective time–cost–quality–environmental impact problem. The performance of the AOA was compared with the adaptive selection slime mold algorithm (ASSMA), which is known to give good results in the literature. The results show that the AOA outperforms the ASSMA in terms of cost, environmental impact, and quality with 25% less function evaluation.
RDL Kalıcı Kaydıİncele - Book ChapterYalnız künye2026Optimization of Time–Cost-Environmental Impact Problems in Construction Projects with Grey Wolf Algorithm
Dede, Tayfun; Yılmaz, Mehmet
In the conventional construction project management, the main focus is generally on the completion time and budget of the project. One of the main objectives of many decision-makers is to complete the project quickly and stay within the specified cost. However, the concepts of sustainability and environmental impact have recently gained prominence on a global scale, which has necessitated greater consideration of the environmental impacts of construction projects. Various scenarios and alternatives are generated during the project planning phase and each of these alternatives has different impacts on the total duration, cost and environmental impact of the project. Therefore, it has become critical for decision makers to identify the most appropriate option. The options selected for the activities can directly affect the overall success, efficiency and sustainability of the project. In the literature, many optimization algorithms have been proposed to solve such multi-objective problems. In this study, the effect of the grey wolf optimization algorithm, inspired by the hunting behavior of grey wolves in nature, on multi-objective time–cost-environmental impact problems encountered in the planning phase of construction projects is investigated. The performance and efficiency of the algorithm are compared with the algorithms in the literature.
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