This study presents a sound-based tool-wear monitoring system designed to overcome the limitations of conventional methods that focus solely on gradual and predictable wear patterns. The proposed system employs low-cost, high-frequency microphones and advanced signal processing—featuring analog/digital filtering, oversampling, signal conditioning, PLL-based synchronization, and feature extraction (ZCR, RMS)—to capture acoustic emissions during machining. Key innovations include optimized microphone placement, a custom PCB, and real-time data transfer via WiFi to MATLAB for analysis. Using the TreeBagger machine-learning algorithm, the system accurately predicts tool wear, detecting both gradual and abrupt wear patterns. Tested on EN 1.4307 (AISI/ASTM 304L) stainless steel, the system demonstrated robust performance in real-time tool-condition assessment. Its scalable and cost-effective design allows for the integration of additional sensors and features, providing a non-invasive and adaptive solution to enhance machining efficiency and reduce operational costs.

The growing demand for electrification increases the likelihood of airport system interferencecaused by electromagnetic emissions. Studies have shown that equipment, installations, andvehicles (including trains, cars, and aircraft) may exceed emissions limits established by manyairports. While minor airport system disruptions, such as radio noise squelch, have been presentfor years, rising emissions may pose risks to critical radio communication and navigationsystems potentially leading to severe consequences. This work provides an overview of airport-related electromagnetic emission standards, comparingproduct-specific standards with current airport emission regulations. The analysisevaluates emission limits across various standards, emphasizing measurement methods, such asdistance, bandwidth, and detectors, alongside their underlying principles. The paper outlineskey challenges which may impact airport operations as electrification expands within both theairport environment and aircraft themselves. Results highlight the complexity of diverse airport environments, showing that a single standardacross an entire airport is impractical. Some equipment will inevitably produce emissions,making product (family) standards, which are hierarchically superior to generic ones, a priority.Notably, road vehicles, high-power equipment and electronic discharge machining productsmay emit significantly more than current regulations permit. Furthermore do preliminarymeasurements indicate that electrically propelled aircraft, airport installations and ground powerunits generate substantial emissions, with high likelihood exceeding defined limits. Overall, the findings presented indicate that further investigations are relevant for standardisation,its implementation, and the impact of emissions from various sources on airport operations.

The growing demand for electrification increases the likelihood of airport system interferencecaused by electromagnetic emissions. Studies have shown that equipment, installations, andvehicles (including trains, cars, and aircraft) may exceed emissions limits established by manyairports. While minor airport system disruptions, such as radio noise squelch, have been presentfor years, rising emissions may pose risks to critical radio communication and navigationsystems potentially leading to severe consequences. This work provides an overview of airport-related electromagnetic emission standards, comparingproduct-specific standards with current airport emission regulations. The analysisevaluates emission limits across various standards, emphasizing measurement methods, such asdistance, bandwidth, and detectors, alongside their underlying principles. The paper outlineskey challenges which may impact airport operations as electrification expands within both theairport environment and aircraft themselves. Results highlight the complexity of diverse airport environments, showing that a single standardacross an entire airport is impractical. Some equipment will inevitably produce emissions,making product (family) standards, which are hierarchically superior to generic ones, a priority.Notably, road vehicles, high-power equipment and electronic discharge machining productsmay emit significantly more than current regulations permit. Furthermore do preliminarymeasurements indicate that electrically propelled aircraft, airport installations and ground powerunits generate substantial emissions, with high likelihood exceeding defined limits. Overall, the findings presented indicate that further investigations are relevant for standardisation,its implementation, and the impact of emissions from various sources on airport operations.