Sürdürülebilir Kalkınma Amaçları

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• MakaleAçık Erişim2026/r/gumushane/12277
  Valorization of Moss biomass as a natural porous Matrix for shape-stable phase change material (PCM) composites

  Can, Ahmet; Ganguly, Sauradipta; Gencel, Osman; Sarı, Ahmet; Erata, Hüseyin

  Phase change materials (PCMs) are used to improve energy efficiency, particularly in building heat storage and passive thermal management applications. In this study, moss biomass ( Calliergonella cuspidata (Hedw.) Loeske) (Ca) was evaluated as a natural porous matrix, and a novel non leachable composite phase change material (PCM) was developed based on n-octadecane (n-OD). The moss biomass was impregnated with 60% n-OD by direct mixing method, and its structural stability was enhanced by the addition of Sodium silicate (SS) at 10% and 30% (by wt%) respectively. The morphological, chemical, and thermal properties of the composites were characterized by SEM, EDS, FTIR, DSC, TGA, XRD, and thermal conductivity analyses. SEM-EDS results showed that the moss biomass (Ca) had high porosity, with the addition of SS resulting in a more compact and homogeneous structure. FTIR analyses exhibited the formation of Si–O–Si bands, indicating successful integration of SS into the matrix. According to DSC analysis, the Ca/n-OD(60%) composite had a melting temperature of 26.1 °C and a melting enthalpy of 153.7 J/g whereas for the SS-added variants, these values were measured as 148.3 J/g (10%) and 144.2 J/g (30%), respectively. The enthalpy losses of only 2–3 J/g after 700 heating-cooling cycles indicated high thermal stability. TGA and XRD analyses showed that the addition of SS increased the thermal resistance of the composites, creating an amorphous network structure. The results indicate that moss-based Ca/n-OD/SS composites, with their compact, leak-free structure, high heat storage capacity, and excellent cyclic stability, hold promise as eco‑friendly materials for subsequent applications in: thermal energy storage for buildings, solar energy systems, and the thermal management of electronic components.

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• MakaleYalnız künye2025/r/gumushane/12355
  Characterization, corrosion, adhesion and wear properties of Al2O3 and Al2O3:TiB2 composite coating on Al 7075 aluminum alloy by one-step micro-arc oxidation method

  Sukuroglu, Suleyman

  This study was carried out in order to increase the usage areas of Al 7075 alloy, which is preferred as an engineering material in the aerospace industry, defense industry and automotive industry, in high temperature applications, wear resistance in different environments and corrosion resistance in aggressive environments. For this purpose, the focus was on the growth of Al2O3 and Al2O3:TiB2 doped composite coatings on the surface of Al 7075 aluminum alloy by the MAO method, and the structural, morphological, corrosion, adhesion and wear properties of the grown coatings in three different environments (atmospheric conditions, brine containing 3.5 % NaCl and oil). Firstly, Al2O3 coatings were grown in electrolytic solution number 1. Secandly, Al2O3:TiB2 doped composite coatings were grown in electrolytic solution number 2 and the phase structure, microstructure and chemical composition of the grown coatings were determined by X-ray Diffraction, Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy, respectively. The abrasion behavior of the coatings in three different environments was determined by a pin-on disc abrasion tester, adhesion resistances were determined by a Scratch Test, and corrosion resistance was determined by a potentiodynamic polarization tester. It was observed that dense and uniform coatings were grown on the surfaces of TiB2 nanoparticle-added (Al2O3:TiB2) coatings, porosity and pore sizes on the surfaces of the coatings were reduced and microcracks were reduced. In addition, it was determined that the corrosion resistance and wear resistance of composite coatings (Al2O3:TiB2) grown with nanoparticle addition increased, and coatings with high bond strength with the substrate were grown.

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• MakaleAçık Erişim2024/r/gumushane/11742
  Prediction of effect of fabrication parameters on the properties of B4C ceramic particle reinforced AA2024 matrix nanocomposites using neural networks

  Varol, Temel; Çanakçı, Aykut; Özşahin, Şükrü; Beder, Murat; Akçay, Serhatcan Berk

  In the present study, a prediction model was created to predict the impact of B4C content, milling time and matrix size on the hardness and density of AA2024-B4C nanocomposites produced by means of flake powder metallurgy. The process involved synthesizing AA2024-B4C nanocomposite powders by mechanical milling followed by preparing nanocomposites by hot pressing. The matrix size of the AA2024 alloy powders, the milling time, and the B4C content were selected as the input parameters. On the other hand, the density and the hardness of the AA2024-B4C nanocomposites were designed as the output parameters. The results showed that the sintered density is significantly improved by decreasing matrix size. It was found that density of AA2024–3 wt%B4C nanocomposites is lower than AA2024–1 wt%B4C nanocomposites. However, the hardness of AA2024–3 wt%B4C nanocomposites is better than AA2024–1 wt%B4C nanocomposites. The AA2024-B4C nanocomposite prediction model could predict hardness and density with a mean absolute percentage error (MAPE) of 0.32% and 1.38%. The results show that the ANN model is a useful tool for the matrix size effect prediction, milling time and B4C content on the density and hardness of AA2024-B4C nanocomposites prepared by flake powder metallurgy.

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