Experimental and Numerical Investigation of the Use of Ultrasonic Waves to Assist Laser Welding.

This study evaluates the enhancement of laser welding using ultrasonic waves aimed at reorganising the intermetallic position in such a fashion that leads to increased mechanical properties of welds in battery pack assemblies for electric vehicles. The experiment employed 20 kHz and 40 kHz High-Power Ultrasound Transducers (HPUTs) in both contact and contactless modes. A simplified experimental configuration is suggested to represent conditions similar to those found in electric vehicle battery pack assemblies. Measurements of vibration transmission to aluminium alloy 1050 plates revealed more than a 1000-fold increase in acceleration amplitude in contact mode compared to contactless mode. The 20 kHz transducer in contactless mode demonstrated superior performance, showing a 10% increase in load and 27% increase in extension compared to welding without ultrasonic assistance. On the other hand, the 40 kHz transducer, while still improved over non-ultrasonic methods, showed less pronounced benefits. This suggests that lower-frequency ultrasonic assistance (20 kHz) is more effective in this specific context. The study explores ultrasonic assistance in laser welding copper (Cu101) to aluminium alloy 1050 using 20 kHz and 40 kHz HPUTs, showing that both transducers enhance microstructural integrity by reducing copper homogenisation into aluminium, with the 20 kHz frequency proving more effective in this context. A numerical simulation was conducted to evaluate the transmission of pressure into the molten pool of the weld, correlated with the vibration results obtained from the 20 kHz transducer. The numerical simulation confirms that no cavitation is initiated in the molten pool area, and all improvements are solely due to the ultrasonic waves.

Rare diseases and space health: optimizing synergies from scientific questions to care.

Knowledge transfer among research disciplines can lead to substantial research progress. At first glance, astronaut health and rare diseases may be seen as having little common ground for such an exchange. However, deleterious health conditions linked to human space exploration may well be considered as a narrow sub-category of rare diseases. Here, we compare and contrast research and healthcare in the contexts of rare diseases and space health and identify common barriers and avenues of improvement. The prevalent genetic basis of most rare disorders contrasts sharply with the occupational considerations required to sustain human health in space. Nevertheless small sample sizes and large knowledge gaps in natural history are examples of the parallel challenges for research and clinical care in the context of both rare diseases and space health. The two areas also face the simultaneous challenges of evidence scarcity and the pressure to deliver therapeutic solutions, mandating expeditious translation of research knowledge into clinical care. Sharing best practices between these fields, including increasing participant involvement in all stages of research and ethical sharing of standardized data, has the potential to contribute to humankind's efforts to explore ever further into space while caring for people on Earth in a more inclusive fashion.