New article published in 12(4A) - ENAN / INAC 2024

X-ray Computed Microtomography for the Inspection of Flexible Risers

Abstract: The integrity of flexible risers, essential for transporting oil from wells to platforms, is often compromised by residual gases such as CO₂ and H₂S, which cause fatigue through corrosion. The marine environment, with its bending loads, radial forces, and internal and external pressures, intensifies this process, requiring continuous monitoring and maintenance to prevent the degradation of the metallic layers. Flexible risers are composed of polymeric and metallic barriers, each with specific functions to ensure flexibility and pressure resistance. However, the rupture of wires in the tensile armor layers, often initiated by manufacturing defects, represents a significant failure mechanism. A gap has been identified in current inspection methods, which are intrusive or have limited sensitivity in some regions of the risers. To address this issue, the use of X-ray Computed Microtomography (microCT) is proposed as a non-invasive technique to detect microcracks in the layers of flexible risers. In this study, a section of flexible riser 440 mm in length and 155 mm in diameter was scanned by the Phoenix V|tome|x M/Waygate Technologies microtomograph, which has a 500 W range microfocus tube and a GE PXR250RT detector with a pixel size of 200 µm. Subsequently, the projections were reconstructed, and the images were analyzed in specialized software. The results showed defects along all layers of the riser. The application of microCT to enhance defect detection is suggested, which could contribute to safer and more reliable offshore oil and gas operations. Read full article. 

X-ray radiographic analysis of the two wooden sculptures of 18th century

Abstract: The X-ray radiography technique is highly efficient in investigating the manufacturing techniques employed by an artisan when creating a sculpture, as well as assessing the state of conservation and restoration processes. For instance, it allows the determination of whether the artist carved the sculpture from a single piece of massive wood or if it was sculpted in multiple parts, subsequently assembled using nails, hooks, or metal spikes. It also provides insights into whether the artwork underwent certain restoration processes and reveals its current state of preservation or degradation. This information can offer insights into the artist preferred creation technique, potentially the most popular technique of the time. It can also help estimate the period when the artwork underwent restoration and aid in choosing the appropriate restoration technique. In this study, we present the results of an investigative analysis of the internal structure, using digital X-ray radiography, of two wooden sacred sculptures representing biblical characters King David and his wife Bathsheba, dating back to the 18th century and housed in the Church of Our Lady of Pilar in Duque de Caxias, RJ, Brazil. Both sculptures are covered with layers of stain, with a prevailing golden hue on the garments. The obtained radiographic images show that the artist carved various parts of the sculptures and later assembled them using metal pegs. Additionally, recent nails were visible, indicating that the sculptures underwent a restoration process. All digital radiographic images were captured in high resolution using a flat-panel detector. Read full article.