We proposed a quasi-distributed vibration sensing technique using in-line weak reflectors and optical frequency domain reflectometry (OFDR). As a result, we achieved an 8 kHz measurable vibration frequency with a 15-20 cm spatial resolution employing a low repetition rate (∼8 Hz). Moreover, a measurable frequency of 30 kHz was achieved for a 1.5 m spatial resolution. The ability of the system to determine the frequency and amplitude of several sections vibrating simultaneously is evaluated for different configurations. Because of the simple arrangement, high detectable frequency, and high sensitivity, this approach is expected to be especially well suited for mechanical vibration sensing applications, particularly in medium-sized structures.
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http://dx.doi.org/10.1364/OL.44.001884 | DOI Listing |
J Am Chem Soc
January 2025
Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433, China.
Metal fatigue, characterized by the accumulation of dislocation defects, is a prevalent failure mode in structural materials. Nondestructive early-stage detection of metal fatigue is extremely important to prevent disastrous events and protect human life. However, the lack of a precise quantitative method to visualize fatigue with spatiotemporal resolution poses a significant obstacle to timely detection.
View Article and Find Full Text PDFJ Inherit Metab Dis
January 2025
Department of Neurology and Pediatric Neurology, Emma Children's Hospital, Amsterdam Leukodystrophy Center, Amsterdam University Medical Center, Amsterdam, The Netherlands.
This study presents the longest systematic prospective follow-up of spinal cord disease in adult male ALD patients to date. Standardized yearly quantitative data collection included scoring of the EDSS, SSPROM, 6-min walking test (6MWT), urological and quality of life questionnaires and vibration sense of the hallux. Progression rates were compared between patients with mild (EDSS ≤ 2.
View Article and Find Full Text PDFMicrosyst Nanoeng
January 2025
School of Engineering, University of Southern Queensland, Springfield, QLD, 4300, Australia.
Various hydrogels have been explored to create minimally invasive microneedles (MNs) to extract interstitial fluid (ISF). However, current methods are time-consuming and typically require 10-15 min to extract 3-5 mg of ISF. This study introduces two spiral-shaped swellable MN arrays: one made of gelatin methacryloyl (GelMA) and polyvinyl alcohol (PVA), and the other incorporating a combination of PVA, polyvinylpyrrolidone (PVP), and hyaluronic acid (HA) for fast ISF extraction.
View Article and Find Full Text PDFSensors (Basel)
December 2024
Institute of Mechanical Intelligence, Scuola Superiore Sant'Anna, Via G. Moruzzi 1, 56124 Pisa, Italy.
CloudSim is a versatile simulation framework for modeling cloud infrastructure components that supports customizable and extensible application provisioning strategies, allowing for the simulation of cloud services. On the other hand, Distributed Acoustic Sensing (DAS) is a ubiquitous technique used for measuring vibrations over an extended region. Data handling in DAS remains an open issue, as many applications need continuous monitoring of a volume of samples whose storage and processing in real time require high-capacity memory and computing resources.
View Article and Find Full Text PDFChildren (Basel)
December 2024
Department of Women's and Children's Health, Division of Paediatric Neurology, Karolinska Institutet, Karolinska University Hospital, S-17176 Stockholm, Sweden.
Background/objectives: Proprioception and sensory disorders have been reported in children with arthrogryposis multiplex congenita (AMC) and myelomeningocele (MMC), but valid and reliable assessment tools are limited in accurately identifying the sensory aspects of motor disorders. This study aimed to investigate the somatosensory status in the feet and legs. An additional purpose of this study was to explore pain, skin irritations, and health status.
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