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Öğe Novel green hydrochar production for renewable fuel substitutes, and experimental investigation of its usability on CI engine performance, combustion, and emission characteristics(Elsevier, 2025-01-21) Sarıdemir, Suat; Polat, Fikret; Simsir, Hamza; Uysal, Cuneyt; Ağbulut, ÜmitIn the present work, green hydrochars from renewable sources (cellulose (HC-Cel), and glucose (HC-Glu) are obtained via the hydrothermal carbonization method. Then different dosages (100 ppm, and 200 ppm) of these nano-sized hydrochar particles are added to the waste cooking oil biodiesel (20 %) and diesel blends (80 %) with the aid of an ultrasonification process. The experiments are performed at an indirect injection, water-cooled, three-cylinder diesel engine. During the experiments, the engine runs at a fixed engine speed of 2000 revolutions per minute (rpm), and at different loading conditions (15–60 Nm with intervals of 15 Nm). Then the impact of hydrochar addition to the diesel-biodiesel blends under these operation parameters is discussed in terms of engine behaviors (combustion, performance, and environmental). Considering the engine performance outputs, the brake specific fuel consumption (BSFC), and brake thermal efficiency (BTE) metrics for B20 are firstly 9.74 % higher, and 9 % lower than D100. The addition of 100 ppm HC-Glu, 200 ppm HC-Glu, 100 ppm HC-Cel, 100 ppm HC-Cel, and 200 ppm HC-Cel to B20 decreased the BSFC values by 17 %, 21.9 %, 15.31 %, 22.76 %, and enhanced the BTE by 13 %, 16 %, 12.07 %, 16.7 %, respectively. On the other hand, significant drops of 27.45 %, 39.22 %, 18.63 %, and 30.39 % for Carbon monoxide (CO) emission, 7.80 %, 12.52 %, 9.11 %, and 11.54 % for Nitrogen oxide (NOx) emission, and 8.91 %, 19.80 %, 5.94 %, and 15.84 % for uHC emission are recorded for B20 + 100 ppm HC-Glu, B20 + 200 ppm HC-Glu, B20 + 100 ppm HC-Cel, and B20 + 200 ppm HC-Cel test fuels, respectively. In conclusion, this work proves that hydrochars are efficient green agents to improve the worsened engine combustion, performance, and emission characteristics of diesel-biodiesel binary mixtures.Öğe The comparative evaluation of the wear behavior of epoxy matrix hybrid nano-composites via experiments and machine learning models(Elsevier, 2025-04) Aydın, Fatih; Karaoğlan, Kürşat Mustafa; Pektürk, Hatice Yakut; Demir, Bilge; Karakurt, Volkan; Ahlatçı, HayrettinThis study evaluated the wear behavior of multiwall carbon nanotube (MWCNT) doped non-crimp fabric carbon fiber reinforced polymer (NCF-CFRP) composites produced through vacuum infusion. Compared to 0 wt% MWCNT reinforced composite, the wear loss of 1 wt% MWCNT reinforced composite under loads of 10 N and 30 N decreased by 48.1 % and 61.1 %, respectively, for sliding distance of 1000 m. Additionally, the study evaluated various Machine Learning models including Deep Multi-Layer Perceptron (DMLP), Random Forest Regression, Gradient Boosting Regression, Linear Regression (LR), and Polynomial Regression for predicting wear loss. The DMLP model exhibited enhanced predictive capabilities in the testing phase (R²=0.9726) compared to its training performance (R²=0.9531), while the LR model maintained stable performance characteristics between training (R²=0.9712) and testing (R²=0.9454) phases.Öğe A comparative study of thermal sprayed Al₂ O₃-TiO₂ coatings on PM AISI 316L(Elsevier, 2024-11-25) Tankal, Kenan; Güney, Bekir; Erden, Mehmet AkifThe widespread use of stainless steels (SS) in various applications is hindered by their inadequate wear resistance, hardness and high density. Structural metallic components fabricated via powder metallurgy (PM) exhibit lower densities compared to those produced by conventional methods due to their inherent high porosity. However, this compromises their mechanical and corrosion performance. This study has investigated the application of pure Al2O3 and Al2O3 + 13 %TiO2 powders with varying particle sizes on PM AISI 316L substrates to enhance their mechanical and wear properties. The phase composition, microhardness, coating morphology, surface roughness, porosity and wear rate of coated and uncoated samples were comparatively analysed to elucidate the influence of both TiO2 addition and coating powder particle size on the mechanical properties and surface morphology of the samples. Microstructural and XRD studies confirmed good mechanical and metallurgical bonding of the coatings to the substrate. All of the coated samples exhibited 24 to 34 times higher surface roughness and 1.3 to 2.1 times lower porosity values compared to the substrate. The finer sized TiO2 added alumina-based coating powder reduced the surface roughness and porosity value to 1.8 and 1.4 times respectively while the use of the coarser sized one reduced these values to 1.3 and 1.2 times respectively compared to the pure Al2O3 coated surface. 8-times higher hardness and 70-times lower wear rate values compared to the substrate were the most significant improvements observed in the pure Al2O3 coated surface among all coated samples. Although TiO2 addition to the coating powder decreased hardness by 1.1 times and increased wear rate by 1.8 times, spraying finer TiO2 added coating powders resulted in a slight improvement in both hardness and wear resistance compared to the coarser one.
