Multiwall carbon nanotubes (MWCNTs) were easily and efficiently decorated with Pd nanoparticles through a vapor-phase impregnation-decomposition method starting from palladium acetylacetonates. The sensor device consisted on a film of sensitive material (MWCNTs-Pd) deposited by drop coating on platinum interdigitated electrodes on a SiO2 substrate. The sensor exhibited a resistance change to ozone (O3) with a response time of 60 s at different temperatures and the capability of detecting concentrations up to 20 ppb. The sensor shows the best response when exposed to O3 at 120 °C. The device shows a very reproducible sensor performance, with high repeatability, full recovery and efficient response.

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This study presents, for the first time, the mechanical behavior of API 5L pipeline steels X42, X52, X60, X70, X80, and X100 with external and internal corrosion defects as well as a combination of both defects that has been named external–internal corrosion defects. The conventional methods to predict failure pressure in corroded pipes, such as B31G, RSTRENG-1, SHELL, DNV-99, PCORRC, and FITNET FFS, have also been discussed in this article. In addition, pipeline failure pressure has been estimated using the finite element method, considering that it is the best approach to calculate actual failure pressure. The external and internal corrosion defect investigated in this research manifests as a rectangular shape with spherical ends at the edges. When the external–internal corrosion defect appears, failure pressure data decrease dramatically because of severe damage. This is due to the decrease in the ligament (effective area) caused by the corrosion defect. To have a good estimation of the pipeline failure pressure with an external–internal corrosion defect, DNV-99 method can be used with acceptable certainty.

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