Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Interaction of Hazelnut-Derived Polyphenols With Biodegradable Film Matrix: Structural, Barrier, and Functional Properties(Multidisciplinary Digital Publishing Institute (MDPI), 2026) Hızır-Kadı, I.; Demircan, E.; Özçelik, B.The study presents a sustainable approach to valorizing hazelnut processing by-products, specifically skins and shells, through their conversion into bioactive polyphenol-rich extracts using pressurized hot water extraction (PHWE), an environmentally friendly green technology. PHWE yielded extracts with total phenolic contents of 25.4 mg GAE/g dw (shell) and 83.7 mg GAE/g dw (skin), which were incorporated into biodegradable poly(vinyl alcohol)/carboxymethyl cellulose (PVA/CMC) films at concentrations of 1–3% (w/v). The resulting composites were comprehensively characterized in terms of structural, mechanical, thermal, and barrier properties. FTIR, DSC, and XRD analyses demonstrated strong hydrogen bonding, increased thermal stability, and reduced crystallinity due to polyphenol–polymer interactions. Phenolic incorporation enhanced UV-blocking capability, increased antioxidant activity by up to five-fold, and reduced oxygen permeability from 0.048 to 0.015 (cm3·mm·m−2·day−1·atm−1) (69% reduction, p < 0.05), compared to neat PVA while maintaining desirable transparency (>70%). Optimal formulations (HSkE-II) exhibited a 39% increase in elongation at break and improved flexibility without compromising film integrity. Application tests using fresh-cut apples, watermelon, and chicken revealed significant reductions in microbial growth (up to ~1.2 log CFU/g), lipid oxidation, and weight loss during storage, confirming the films’ potential for active food packaging. This work highlights an efficient valorization strategy for nut industry by-products and demonstrates their functional integration into sustainable biodegradable packaging systems. © 2025 by the authors.Article A Study of the Environmental Challenges En Marche Towards Net-Zero: Case Study of Turkish Steel Industry(Multidisciplinary Digital Publishing Institute (MDPI), 2026) Özdamar, A.B.; Kaya, M.; Bektas, A.; Bhattacharyya, S.; Şahindoğan, M.; Birat, Jean-Pierre; Dutta, A.The Turkish steel industry aims to reduce its sectoral carbon dioxide (CO<inf>2</inf>) emissions by 55% by 2030, in line with Türkiye’s Paris Agreement commitments and the European Green Deal (EGD), and consistent with the ambition of the European Union’s economy-wide ‘Fit for 55’ emissions-reduction target. Türkiye faces significant challenges in achieving net-zero greenhouse gas (GHG) emissions, particularly as a developing country confronting the impacts of climate change and in the market situation, such as the effects of the ongoing Russia-Ukraine conflict, limited access to affordable raw materials, and rising operational costs. This study serves as a guideline for the Turkish steel sector’s roadmap towards modernization and eventual compliance with net-zero targets. The consideration and integration of new technologies planned for the Turkish steel industry, in both electric arc furnace (EAF) and blast furnace-basic oxygen furnace (BF-BOF) facilities, have been outlined in conjunction with green hydrogen and with Carbon Capture and Storage (CCS) technologies. Four different scenarios were analysed to understand the reduction in CO<inf>2</inf> emissions: (1) In a Business-As-Usual (BAU) scenario without any reduction, (2) 39.9% CO<inf>2</inf> emission reduction with the Moderate scenario, (3) 59.6% reduction with the Advanced scenario, and (4) 82.9% reduction in CO<inf>2</inf> emissions from the Turkish steel sector with the Net-Zero scenario. To quantify the uncertainty in these long-term projections, a Monte Carlo simulation was conducted, generating probabilistic confidence intervals that reinforce the robustness and credibility of the net-zero pathway. The official roadmap for the sector is not available as of today; however, an in-depth discussion with a policy innovation leading to it is the objective of this study. © 2026 by the authors.Article Amino Acid Selection Altered Silver Nanoparticles Morphology and Formation of Silver Oxide Layers(Multidisciplinary Digital Publishing Institute (MDPI), 2025) Bolat, Ş.; Sancak, Z.; Gumus, A.; Yazgan, I.Amino acids are not just monomers of proteins, but they can also carry biological functions. L-cysteine (Cys), L-proline (Pro), L-asparagine (Asn), and L-glutamic acid (Glu) were used to evaluate how different amino acid chemistries alter the morphology and size of the silver nanoparticles (AgNPs) synthesized in the presence of two carbohydrate ligands, which were lactose methoxyaniline (LMA) and galactose 5-aminosalicylic acid (G5AS). UV–vis, infrared (IR), High-Resolution Transmission Electron Microscopy (HR-TEM) and X-ray diffraction (XRD) characterizations revealed that the effect of amino acids on the characteristics of the AgNPs showed dependence on the carbohydrate ligand chemistry. In the case of LMA, AgNPs shifted from aggregates to anisotropic nanoparticles, larger aggregates, and a mixture of anisotropic and 1D nanoparticles in the presence of Cys, Glu, Asn and Pro amino acids, respectively. In contrast to this, the introduction of Cys and Asn caused the formation of cluster-like AgNPs and larger rounded nanoparticles, while G5AS-synthesized AgNPs were multigonal 0D particles. Moreover, Glu and Pro contributed the resistance of silver oxide formation on the particles. Antibacterial characterization showed that LMA_Glu_AgNPs were the most effective ones, while LMA_Cys_AgNPs and G5AS_Cys_AgNPs, which were the smallest AgNPs, did not show any significant antibacterial activity. © 2025 Elsevier B.V., All rights reserved.Article Citation - WoS: 5Citation - Scopus: 6Effect of Graphene Nanoplatelet Content on Mechanical and Elevated-Temperature Tribological Performance of Self-Lubricating Ze10 Magnesium Alloy Nanocomposites(Multidisciplinary Digital Publishing Institute (MDPI), 2024) Kandemir,S.; Yöyler,S.; Kumar,R.; Antonov,M.; Dieringa,H.Magnesium (Mg) and graphene in alloy formulations are of paramount importance for lightweight engineering applications. In the present study, ZE10 Mg-alloy-based nanocomposites reinforced with graphene nanoplatelets (GNPs) having a thickness of 10–20 nm were fabricated via ultrasound-assisted stir casting. The effect of GNP contents (0.25, 0.5, and 1.0 wt.%) on the microstructure, Vickers hardness, and tensile properties of nanocomposites was investigated. Further, tribological studies were performed under a ball-on-disc sliding wear configuration against a bearing ball counterbody, at room and elevated temperatures of 100 °C and 200 °C, to comprehend temperature-induced wear mechanisms and friction evolution. It was revealed that the GNP addition resulted in grain coarsening and increased porosity rate of the Mg alloy. While the composites exhibited improved hardness by 20–35% at room temperature and 100 °C, a minor change was observed in their hardness and tensile yield strength values at 200 °C with respect to the GNP-free alloy. A notable improvement in lowering and stabilizing friction (coefficient of friction at 200 °C~0.25) and wear values was seen for the self-lubricating GNP-added composites at all sliding temperatures. The worn surface morphology indicated a simultaneous occurrence of abrasive and adhesive wear mode in all samples at room temperature and 100 °C, while delamination and smearing along with debris compaction (tribolayer protection) were the dominant mechanisms of wear at 200 °C. Inclusively, the results advocate steady frictional conditions, improved wear resistance, and favorable wear-protective mechanisms for the Mg alloy–GNP nanocomposites at room and elevated temperatures. © 2024 by the authors.