In this paper, the surface acoustic wave velocity results acquired from the inspection of specially manufactured and characterised alumina ceramic materials are presented. Ultrasonic velocity data of alumina-based ceramics in the range 60-100% theoretical density was generated utilising non-contacting laser-ultrasonic measurements based on laser generation and detection of surface acoustic waves with the objective of creating a routine technique for industrial advanced alumina inspection. With linear fitting the surface acoustic wave velocity data serves as a calibration graph for using laser ultrasonics for routine monitoring of alumina. A second laser ultrasonic technique based on the laser generation and foil transducer detection of surface acoustic waves was used to validate the surface acoustic wave velocities measured by the laser generation/detection technique.
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http://dx.doi.org/10.1016/s0041-624x(99)00164-x | DOI Listing |
Sci Rep
January 2025
School of Mechanical and Engineering, Liaoning Technical University, Fuxin, 123000, China.
As the depth of coal mining in China continues to increase, the fracturing of coal rock masses has an increasingly complex impact on the surrounding rock roadways. The majority of the mine's roadways run through coal rock masses with hard roofs and soft bottoms, which typically exhibit complex dynamic behaviour. To further research the mechanical behaviour and fracture evolution of coal rock masses under hard-roof and soft-floor conditions, the study is based on the majority of working faces in a mine, which have hard roofs and soft floors.
View Article and Find Full Text PDFMagn Reson Med
January 2025
MRI Research Centre, Physics, University of New Brunswick, Fredericton, New Brunswick, Canada.
Purpose: Magnetic resonance elastography (MRE) provides detailed maps of tissue stiffness, helping to diagnose various health conditions, but requires the use of expensive clinical MRI scanners. Our approach utilizes compact, cost-effective portable MR sensors that offer bulk characterization of material properties in a region of interest close to the surface (within 1-2 cm). This accessible instrument could enable routine monitoring and prevention of diseases not readily evaluated with conventional tools.
View Article and Find Full Text PDFJ Mech Behav Biomed Mater
January 2025
Laboratory for Biomechanics and Biomaterials (LBB), Department of Orthopedic Surgery, Hannover Medical School, Anna-von-Borries-Strasse 1-7, 30625, Hannover, Germany. Electronic address:
In hip arthroplasty, relative movements between the femoral stem and bone can lead to implant loosening, resulting in extensive bone loss. Acoustic emission (AE) analysis is a promising technique for a nondestructive and noninvasive detection of these relative movements. To develop such a detection method, in vitro investigations using piezoelectric AE sensors on implant stems in artificial or human femora are required to characterize the AE signals induced by loosening.
View Article and Find Full Text PDFSci Total Environ
January 2025
Center for Marine Sensors, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, 26382 Wilhelmshaven, Germany.
Microplastics (MP) are known to be ubiquitous. The pathways and fate of these contaminants in the marine environment are receiving increasing attention, but still knowledge gaps exist. In particular, the link between mass-based MP quantification and oceanographic parameters is often lacking.
View Article and Find Full Text PDFSensors (Basel)
January 2025
Beijing Key Laboratory for Precision Optoelectronic Measurement Instrument and Technology, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China.
Optical freeform surfaces are widely used in imaging and non-imaging systems due to their high design freedom. In freeform surface manufacturing and assembly, dynamic freeform surface measurement that can guide the next operation remains a challenge. To meet this urgent need, we propose a dynamic interferometric method based on a machine learning-configured deformable mirror (DM).
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