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    A Novel Approach to the Development of Natural Resin-Based Biopolymer in the Presence of a Reusable Catalyst: Characterization and Modeling of Material Properties
    (Wiley, 2025) Angin, Naile; Ertas, Murat; Aras, Omur; Genc, Merve
    The rise in environmental and health concerns has led to increasing attention to nature-derived materials. Natural resin (NR) is secreted by pine trees, and it is a great monomer source for synthesizing biopolymers. The objective of this study is to produce terpene rosin phenolic resin (TRPR) from NR, turpentine, and phenol by applying a novel polymerization technique. An environmentally friendly and reusable catalyst (Amberlyst15) was chosen instead of traditional ones. TRPR samples were chemically characterized using Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), and gel permeation chromatography (GPC) analysis. The average molecular weight (Mw) of TRPR was detected as 560 g/mol. Artificial neural network (ANN) modeling was designed with three inputs (pressure, temperature, and terpene/NR ratio) and four outputs (reaction yield, acid value, saponification value, and softening point). The highest TRPR yield was obtained with a terpene/NR ratio of (1/2) at 80 degrees C and under 3 atm. The lowest acid and saponification values were calculated as 90.54 and 100.11 mg KOH/g, respectively. The softening point of TRPR reached 80 degrees C and it was suggested for use in the paper, ink, and adhesive industries. image
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    Aging resistance and adhesion strength of cold plasma treated aluminum-polypropylene joints: The role of surface treatments and curing agents
    (Elsevier Sci Ltd, 2025) Oymak, Zumre; Aras, Omur
    With the developing technology, Aluminum (Al) - Polypropylene (PP) composite materials, which combine lightness and high durability, are widely used especially in the aviation and automotive sectors. In this study, different combinations of surface treatment methods such as; sanding, sandblasting, chemical etching, anodization and cold vacuum plasma, were applied to the surface of PP and Al plates. After treatment procedures, these surfaces bonded with epoxy adhesives prepared with Triethylenetetramine (Teta), m-Xylenediamine (Mx) and Phenalkamine (PA) curing agents. The effect of the aging process on the bonding strength was investigated on various samples kept in a hot water bath for 2 months. Contact angle measurement, topography analyses, FTIR and tensile test measurements were conducted for evaluation of the given effects. In the experiments, the highest strength was obtained by bonding of sanded/plasma-treated PP plates with the chemical etched/ anodized/plasma-treated Al plates. Compared to the non-surface treatment plates, an increase of 558.72 % was achieved and a tensile strength of 1840 N (9.2 MPa) was handled. According to the aging results, it was determined that the greatest decrease in adhesion strength occurred in the plates bonded with Teta, while the least decrease occurred with PA curing agent. More resistant structures to the aging were obtained by first sandblasted, then anodized and then plasma applied aluminum plates bonded with sanded and plasma activated PP surfaces. It was determined that especially plasma-treated surfaces were more resistant to the aging than nonplasma activated surfaces.
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    AI-Driven Modeling and Statistical Assessment of AgO/ZnO/g-C3N4 Photocatalysts on Wastewater Treatment: Impact of UV-Visible Light
    (Wiley-V C H Verlag Gmbh, 2025) Yoney, Busra; Aras, Omur
    Minimizing the environmental impact of dye-laden wastewater, remains a critical challenge with high economic implications. This study focuses on the development and optimization of g-C3N4-based photocatalysts doped with AgO and ZnO at varying Zn (0%-100%) and Ag (0%-2.5%) loadings. Catalysts were applied at four dosages (0.03-0.12 g/100 mL), and their methylene blue degradation efficiencies were evaluated over time intervals up to 3 h. Photocatalysts were synthesized using both conventional and ultrasound-assisted (US-assisted) co-precipitation methods. The US-assisted synthesis yielded improved morphology and dispersion, as evidenced by SEM-EDS and XRD analyses, and enhanced photocatalytic performance. Experimental data were used to train three AI models; artificial neural network (ANN), support vector regression (SVR), and Random forest (RF). SVR exhibited the highest predictive accuracy (R-2 = 0.9854, RMSE = 0.0401), while ANN and RF also showed strong performance (R-2 approximate to 0.980). Model robustness was validated through residual analysis and statistical tests. To assess the influence of input variables, one-way and multi-factor Type II ANOVA were conducted. Zn and Ag content, catalyst dosage, and reaction time were all statistically significant (p < 0.05), with US treatment and Zn loading having the most dominant effects. Ag's contribution was also significant but more composition-dependent.
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    Effect of pre-anodizing, electrocoating processes and fatty acid chain length on morphology, roughness and durability of ZnO-coated superhydrophobic surfaces
    (Springer Heidelberg, 2022) Aras, Omur; Baydir, Enver; Akman, Bugra
    Anodizing process was applied for the first time in this study for pre-modification of the 1050 aluminum surface before the zinc electrodeposition to obtain superhydrophobic surface by modifying with palmitic, lauric and stearic acid for the comparison. The effect of the pre-anodizing process, the electrodeposition time and the acid chain length on the super-hydrophobicity and durability was investigated in detail to explain the relationships between the roughness, morphology and acid chain length. Anodized, electrocoated and modified surfaces were characterized by FTIR, XRD, SEM and topography analysis. The highest contact angles were 154 degrees, 157 degrees and 160 degrees for electrodeposition process modified with lauric, palmitic and stearic acid, respectively. Sandpaper abrasion, UV, pH and temperature tests showed that molecular length, pre-anodizing and coating time strongly related the durability and super-hydrophobicity of the coated surfaces. As a result, anodizing time has a great impact on the durability and contact angle compared to non-anodized plates thanks to the creating macro-roughness.
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    Mineralization of o-tolidine by electrooxidation with BDD, Ti/Pt and MMO anodes
    (Desalination Publ, 2019) Can, Orhan Taner; Bayramoglu, Mahmut; Sozbir, Mustafa; Aras, Omur
    The present study deals with the electrooxidative mineralization of o-tolidine from aqueous solution using various Ti/Pt, mixed metal oxide (MMO) and boron doped diamond (BDD) anodes. The experiments were carried out in two phases. In the first phase, the effect of anode type on the total organic carbon (TOC) removal efficiency was investigated at various pH levels. Furthermore, the second phase was carried out with the most effective anode, to investigate the effects of various operating parameters on the TOC removal efficiency, such as current density, stirring speed, inter electrode distance, concentrations of o-tolidine and the electrolyte. Also, specific energy consumption (SEC) based on the amount of electricity consumed for TOC removal was estimated. The results showed that BDD anode was much more efficient than Ti/Pt and MMO anodes for the mineralization of o-tolidine. The current density and stirring speed were the most effective parameters. With BDD anode, TOC removal efficiency realized as 54.6% and 79.9% for the current density of 25 mA/cm(2) and 125 mA/cm(2) respectively, at 150 min of processing time. On the other hand, TOC removal efficiency realized as 51.5% and 79.1% at stirring speeds of 0 and 1000 rpm at 150 min.
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    Synergy of 3D, porous supports and surface alkalinity tendency in Cu/ZnO catalysts for methanol steam reforming
    (Pergamon-Elsevier Science Ltd, 2026) Baydir, Enver; Aras, Omur
    The growing recognition of hydrogen as a strategic energy carrier has increased the need for efficient lowtemperature processes. Methanol steam reforming (MSR) is promising due to its mild operating conditions. Packed-bed reactors are widely used; however, achieving high conversion and selectivity is difficult because of heat and mass transfer limitations and poor reactant-catalyst contact, often requiring higher temperatures or alternative designs. This work addresses these challenges by developing three-dimensional, porous supports with controlled Ca modification. Zeolite- and kaolin-based supports were prepared by wet granulation and modified with different Ca(OH)2 loadings. Moderate Ca addition promoted CaO formation and improved porosity, whereas excessive loading reduced it, impairing performance. Z-HP-15Ca@Cu/ZnO showed the best zeolite performance, while K-HP-10Ca@Cu/ZnO was optimal for kaolin. Statistical analysis confirmed higher conversion for zeolitebased catalysts. Overall, this strategy couples Ca-derived surface species with support porosity to achieve high MSR performance at low temperatures.
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    The role of CO adsorption and CuO formation on the catalyst deactivation during the long-term performance evaluation of methanol steam reforming process for hydrogen production: Comparison of sono-coprecipitation and spray pyrolysis method
    (Pergamon-Elsevier Science Ltd, 2022) Baydir, Enver; Aras, Omur
    In this study, microreactors were coated with catalysts synthesized by two different methods and hydrogen was produced by methanol steam reforming. The structure of the catalysts was characterized by XRD, SEM and EDS analyses in the synthesis, activation and after long-term evaluation stages. The effect of CO adsorption and the structural changes of catalysts on the product stream and conversion were investigated and compared in detail. As a result, it was observed that the catalyst prepared by sono-coprecipitation (SCC) was more active although lost its performance much faster. Considering the performance graphs, SEM/EDS analyses and XRD results, it was revealed that the main reason for the performance decrease of the SPC-reactor (spray pyrolysis coating) was the increase of CO adsorption on the surface. Also, the formation of CuO structures and CO adsorption in the SCC-reactor were responsible for the faster performance decrease.(c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.