This study presents a failure analysis in two reformer tubes used for hydrogen production in a petrochemical industry. These tubes (Tube A and Tube B) were made by the centrifugal casting of HP-Nb alloy in such a way that one contained titanium as a micro-element, and the other was free from titanium in its chemical composition. Although the two tubes were subjected to similar creep conditions, Tube A failed after only 46,000 h of operation against the design life of 100,000 h. SEM images showed initiation and growth of creep pores next to chromium carbide particles, as well as the formation of microcracks in Cr23C6 carbides. Pore initiation occurs as a result of grain boundary sliding and is strongly dependent on structural morphology. The tube containing titanium (Tube B) showed higher thermal stability and higher creep resistance than the tube without titanium (Tube A), which was due to the formation of finer and more discrete carbide particles. The final fracture of the tube without titanium (Tube A) occurred due to the coalescence of creep pores and the creation of grain boundary cracks.@en

This paper investigates the synthesis and characterization of photoactive TiO₂/CuO nanocomposites for the simultaneous antibacterial applications and photocatalytic removal of Amoxicilline from wastewaters. Effective removal of biological and organic contaminants from water resources has become a global challenge due to contaminants' complexity and extensive use. TiO₂/CuO heterojunctions with different CuO loadings were synthesized using a straightforward precipitation method. Electron microscopy, energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Fourier transformed infrared (FTIR), ultraviolet–visible (UV-VIS) analyses were used to characterize synthesized samples. Antibacterial activities of samples were investigated against Staphylococcus aureus. Also, the applicability of synthesized powders in the photocatalytic removal of Amoxicilline from wastewater was methodically investigated. Results showed that the photocatalytic activity of synthesized TiO₂/CuO nanocomposites is highly dependent on the CuO loadings of samples. CuO loading can also increase the light absorption within the visible light region, making TiO₂/CuO samples applicable in the visible light region. Results also showed that CuO loading greatly enhances the antibacterial characteristics of samples.

@en