Detection of early-stage corrosion on slender steel members is crucial for preventing buckling failures of steel structures. An active photoacoustic fiber optic sensor (FOS) system is reported herein for the early-stage steel corrosion detection of steel plates and rebars using surface ultrasonic waves. The objective of this study is to investigate a potential method for detecting surface corrosion/rust of steel rods using numerically simulated surface ultrasonic waves. The finite element method (FEM) was applied in the simulation of propagating ultrasonic waves on steel rod models. The pitch-catch mode of damage detection was adopted, in which one source (transmitter) and one sensor (receiver) were considered. In this research, radial displacements at the receiver were simulated and analyzed by short-time Fourier transform (STFT) for detecting, locating, and quantifying surface rust located between the transmitter and the receiver. From our time domain and frequency domain analyses, it was found that the presence, location, and dimensions (length, width, and depth) of surface rust can be estimated by ultrasonic wave propagation.

Detection of early stage corrosion on slender steel members is crucial for preventing buckling failures of steel structures. An active photoacoustic fiber optic sensors (FOS) system has been reported for early stage steel corrosion detection of steel plates and rebars using surface ultrasonic waves. The objective of this paper is to investigate the surface corrosion/rust detection problem on steel rods using numerically simulated surface ultrasonic waves. The finite element method (FEM) is applied in simulating the propagation of ultrasonic waves on steel rod models. Transmission mode of damage detection is adopted, in which one source (transmitter) and one sensor (receiver) are considered. In this research, radial displacements at the receiver were simulated and analyzed by short-time Fourier transform (STFT) for detecting, locating, and quantifying a surface rust located between the transmitter and the receiver. From our time domain and frequency domain analyses, it is found that the presence, location, and dimensions (length, width, and depth) of surface rust can be estimated by ultrasonic waves propagating through the surface rust.

The escalating levels of atmospheric CO₂, primarily attributed to human activities, underscore the urgent need for innovative solutions to mitigate environmental challenges. This study delves into the electrochemical reduction of CO₂ as a promising avenue for sustainable carbon capture and utilization. Focused on the formation of formate (HCOO⁻/HCOOH), a high-value product, the research explores the integration of nonthermal plasma (NTP) with electrochemical processes—an approach rarely studied in existing literature. A comprehensive investigation involves varying parameters such as plasma discharging voltage, carrier gas, discharging mode, electrolysis voltage, polarity, and plasma type. The electrochemical tests employ a 10 wt.% Pd/C catalyst, and formate production is quantitatively analyzed using NMR. Results reveal that NTP significantly enhances CO₂ reduction, with key factors influencing formate yield elucidated. The study reveals the complexity of CO₂ electrochemical reduction, providing novel insights into the synergistic effects of NTP. These findings contribute to advancing sustainable technologies for CO₂ utilization, paving the way for more efficient and environmentally friendly processes in the pursuit of a carbon-neutral future.

We report ambient‐condition ammonia synthesis via plasma‐mediated electrocatalysis that couples a nonthermal plasma (NTP) with an electrochemical cell. In this hybrid scheme, the plasma pregenerates long‐lived, soluble nitrogen intermediates (predominantly NO ₃ ⁻ /NO ₂ ⁻ ) from N ₂ /H ₂ O, which are subsequently electrochemically reduced to NH ₃ . Using a dual‐chamber H‐cell (2.5 kV NTP, ~6–7 mA plasma current; −0.5 V vs. Ag/AgCl), we find that Ar plasma doubles NH ₃ production relative to electrochemistry alone, and N ₂ plasma provides a further approximately 50% increase. Acidic electrolytes are critical: 0.5 M H ₂ SO ₄ maximizes NH ₃ yield, while tuning acid concentration balances NH ₃ selectivity against HER. Humidifying the N ₂ plasma increases nitrate from approximately 5400 to approximately 7100 ppm and boosts NH ₃ by approximately 21%, consistent with enhanced formation of soluble nitrogen intermediates. Catalyst screening shows PtIr and Pd outperform Pt/C, NbN, and NbO ₂ , indicating that in the plasma‐assisted regime the rate‐limiting step shifts from nitrate activation to hydrogenation, favoring catalysts that efficiently supply surface hydrogen. Time‐resolved measurements reveal steady NH ₃ accumulation with nonmonotonic NO ₃ ⁻ evolution, reflecting a competition between plasma‐driven formation and electroreduction. Under optimized conditions (N ₂ plasma; 0.3 M–0.5 M H ₂ SO ₄ ), the Faradaic efficiency (FE) reaches up to 47%; total specific energy consumption for our present setup is approximately 73 kWh/kg NH ₃ , dominated by the plasma input, indicating clear opportunities for reduction via high‐frequency operation and reactor optimization. These results establish plasma–electrochemical coupling as a tunable route to decentralized, ambient NH ₃ synthesis and outline design principles for plasma‐compatible electrocatalysts and reactors.