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    Al-5Cu/B4Cp composites: The combined effect of artificially aging (T6) and particle volume fractions on the corrosion behaviour
    (Elsevier, 2020) Tozkoparan, Burak; Dikici, Burak; Topuz, Mehmet; Bedir, Fevzi; Gavgali, Mehmet
    In this study, the Al-5Cu matrix composites reinforced with different boron carbide (B4C) particle volume fractions have been successfully produced by the hot-pressing method. Then, the artificially aging (T6) was applied to the composites for increasing their mechanical properties. The combined effect of the T6 heat treating and the B4C particle volume fraction on the corrosion behaviour of the composites were investigated by potentiodynamic scanning (PDS) technique under aerated and deaerated 3.5% NaCl marine environments. The effect of the T6 treating on the hardness and corrosion susceptibilities of the composites were also evaluated microstructurally to contribute to their industrial use and production processes. The microstructural characterization of the composites was carried out by using a scanning electron microscope (SEM) with an attached energy dispersive spectrum (EDS) and X-ray diffraction (XRD). It was found that the corrosion susceptibilities of the composite have been interestingly decreased with increasing the B4C particle volume fraction in the matrix while the T6 treatment enhances the pitting susceptibility of the composites. The reason of the behaviour has been discussed in details the text. (C) 2020 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.
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    The effect of high TiC particle content on the tensile cracking and corrosion behavior of Al-5Cu matrix composites
    (Sage Publications Ltd, 2020) Dikici, Burak; Bedir, Fevzi; Gavgali, Mehmet
    The high-TiC particle volume fraction on the mechanical properties and corrosion behavior of the A-5Cu matrix composites were investigated with porosity, hardness, tensile tests, and polarization measurements. The composites reinforced with 18, 27, and 50 vol% TiC particulates were produced successfully by using hot-pressing technique under Ar atmosphere and characterized by scanning electron microscope, electron dispersive spectroscope, and X-ray diffraction. The corrosion susceptibilities of the composites were compared with potentiodynamic scanning technique. It was found that the hardness of the composites increases while the fracture strength decreases with increasing TiC reinforcement content in the matrix. The corrosion susceptibilities of 18 and 27 vol% TiC-reinforced composites are almost the same; the corrosion rate of 50 vol% TiC-reinforced composite was approximately 10 times higher than the composites reinforced with 18 and 27 vol% TiC particles in the 3.5% NaCl. In addition, some preferential corrosion attacks were detected at TiC/matrix interfaces and in TiC clusters during the corrosion process of the composites. Therefore, the porosity content in the composites was almost the same level.
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    Is Urinary Kidney Injury Molecule-1 a Noninvasive Marker for Renal Scarring in Children With Vesicoureteral Reflux?
    (Elsevier Science Inc, 2013) Toker, Aysun; Ziypak, Tevfik; Orsal, Ebru; Laloglu, Esra; Bedir, Fevzi; Aksoy, Yilmaz
    OBJECTIVE To examine whether (1) levels of urinary kidney injury molecule-1 (KIM-1), a transmembrane protein and biomarker for renal tubular damage, increase in children with of vesicoureteral reflux (VUR), and (2) if KIM-1 predicts the grade of renal scarring in children with VUR. METHODS The study included 59 VUR patients with renal scarring, 5 VUR patients without renal scarring and 25 healthy controls aged 1 to 17 years. Dimercaptosuccinic acid scans were performed for determination of scarring and graded by 3 independent, blinded pediatric urologists for renal scarring according to the Randomized Intervention for Children with VUR study criteria. Spot urine samples were obtained. Urinary KIM-1 and creatinine levels were measured and the KIM-1/creatinine ratio was calculated. RESULTS Urine geometric mean KIM-1 levels (ng/mg creatinine) were significantly higher in VUR patients than in healthy controls (P = .018). Although the correlation between VUR grade and geometric mean KIM-1 levels was not significant, a positive correlation was found for scarring grade and geometric mean KIM-1 levels (r = .30, P = .02). When the patients were divided by subgroups according to scarring grade (group I, grade 1; group II, grades 2 and 3; group III, grade 4), the log KIM-1 in group III was significantly higher than in group I (P = .004). CONCLUSION Urinary KIM-1 levels might be used as a noninvasive marker, particularly in showing severe scarring in children with VUR. UROLOGY 81: 168-172, 2013. (C) 2013 Elsevier Inc.