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    Advanced tribological performance of PVD AlTiCrN and TiCrN coatings under dry and lubricated conditions
    (Elsevier Ltd, 2026) Ataş Bakdemir, Seda; Özkan, Doğuş; Arpacı, Kürşat Alp; Türküz, Cenk; Konar, Melisa; Sulukan, Egemen
    TiCrN and AlTiCrN multilayer coatings were fabricated on H13 steel substrates through the cathodic arc physical vapor deposition (PVD) technique. Comprehensive structural, mechanical, and tribological characterizations were performed to evaluate their behavior under dry and lubricated sliding conditions. When the mechanical properties of the coatings are evaluated, it is observed that although the AlTiCrN coating exhibits higher hardness (29.38 GPa) compared to the TiCrN coating (24.15 GPa), its adhesion strength is lower, corresponding to an HF4 classification. XRD and Raman analyses confirmed the formation of both coatings with a preferred (200) orientation and characteristic Ti–Cr–Al–N vibrational modes. AFM results demonstrated higher surface roughness for AlTiCrN due to increased droplet density. Tribological tests showed that TiCrN provided superior friction and wear performance under dry conditions, whereas AlTiCrN exhibited better tribological response under lubrication and wear resistance at lower loads, though localized spallation occurred at higher loads, indicating load-dependent degradation. SEM/EDX analysis revealed oxide formation on the wear scars of the TiCrN coating, which contributed to its lower COF under dry conditions, whereas the AlTiCrN coating preserved its constituent elements without oxide formation or substrate exposure. Under lubricated conditions, TiCrN showed localized Fe signals indicating partial substrate exposure and abrasive wear, whereas AlTiCrN retained its surface composition, confirming better wear protection.
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    Enhancing efficiency in Peltier-cooled atmospheric water harvesting: a mathematical modeling and experimental study
    (Elsevier Ltd, 2026) Heidarnejad, Parisa; Sulukan, Egemen; Dedecan, Abdullah; Köse, Ali; Yıldırım, Furkan
    Water scarcity is one of the biggest global challenge, threatening current generation and necessitating alternative solutions. Among various technologies, atmospheric water harvesting systems offer a viable solution. The objective of this study is to present and assess an innovative geometry for Peltier-cooled atmospheric water harvesting system intended to improve drinkable water production through enhancing both mixing and heat transfer in the cold-side extended surfaces. The initial section of this study involves mathematical modeling. Findings of modeling section, illustrate an output of 1.97 L/day under conditions of 84.8% relative humidity and an ambient temperature of 32°C. The second section involves the design, fabrication, and performance evaluation of the system. The experimental observations indicate a water generation of 1.97 L/day in Test 1 (84.8% relative humidity, 32˚C), 1.63 L/day in Test 2 (85.8% relative humidity, 24.2˚C), 1.45 L/day in Test 3 (79% relative humidity, 25.4˚C), 1.29 L/day in Test 4 (76% relative humidity, 30˚C), and 1.13 L/day in Test 5 (69% relative humidity, 22.5˚C). These findings demonstrates the significant impact of environmental factors on the system's water generation performance. Moreover, novel geometry of the air inlet and exit channels improved the effectiveness of the water harvesting of the prototype across all test scenarios when compared with results reported in the literature. The outputs derived from modeling and experimental analysis, exhibit a strong correlation, thereby validating the model and highlighting the capability of the proposed system as a sustainable approach to global water scarcity problems.