Methane thermal decomposition is a promising technology for producing CO₂-free hydrogen. This study experimentally examines how temperature (1,000–1,400^oC) and residence time affect methane decomposition in a ceramic tubular reactor. The results show that both the methane conversion rate and hydrogen yield increased with temperature, reaching approximately 95% and 45%, respectively, at 1,400^oC. At lower temperatures (1,000–1,200^oC), residence time had a significant impact, while at higher temperatures (1,300–1,400^oC), temperature became the predominant factor. Additionally, the formation of C₂ hydrocarbons, particularly acetylene (C₂H₂), increased as residence time decreased, negatively affecting both methane conversion and hydrogen yield. Analysis of the solid carbon by-products identified two distinct forms: amorphous, spherical carbon black particles and a semi-graphitic, crystalline carbon film. These findings provide essential data for optimizing the conditions of methane thermal decomposition.

This study numerically investigates the spreading and retracting dynamics of Janus drops on the inner surfaces of cylinders using the Volume of Fluid method. The results indicate that increasing surface curvature enhances spreading in the axial direction and promotes the detachment of the low-viscosity water component, particularly under conditions of high viscosity ratio and Weber number. A regime map is constructed to identify the critical conditions for separation, revealing that surfaces with intermediate curvature exhibit higher separation efficiency compared to those with high curvature. The temporal evolution of axial momenta in the x and z directions highlights the role of viscosity contrast in inducing asymmetric deformation. A scaling law for residence time is proposed as a function of Weber number, which aligns well with simulation results in the high Weber number regime. These findings provide fundamental insights for optimizing surface curvature and fluid composition to enhance drop separation and may benefit applications such as selective liquid extraction, surface cleaning, and microfluidic manipulation.