A new approach to nonlinear frequency mixing based on local damage resonance is proposed, analysed and tested experimentally for flexural waves in composites. The method is free from stringent requirements on the mode types and frequencies for interacting waves. The resonance of damage enhances strongly its higher-order nonlinear response and boosts the efficiency of generation for numerous-order combination frequencies. The damage resonance combined with its strong nonlinearity also provides locality of nonlinear interaction even for continuous wave operation. The combination frequencies generated locally in the damaged area are the footprints of damage and used for its detection, location and visualization. A single C-scan yields a number of images of the defect corresponding to various nonlinearly generated frequencies. Various versions of the resonant frequency mixing are considered and applied to nonlinear imaging of defects in composite materials.
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http://dx.doi.org/10.1016/j.ultras.2020.106221 | DOI Listing |
Viruses
December 2024
Departamento de Biología del Estrés y Patología Vegetal, Centro de Edafología y Biología Aplicada del Segura (CEBAS)-CSIC, C.P. 30100 Murcia, Spain.
Mixed infections of plant viruses are common in crops and represent a critical biotic factor with substantial epidemiological implications for plant viral diseases. Compared to single-virus infections, mixed infections arise from simultaneous or sequential infections, which can inevitably affect the ecology and evolution of the diseases. These infections can either exacerbate or ameliorate symptom severity, including virus-virus interactions within the same host that may influence a range of viral traits associated with disease emergence.
View Article and Find Full Text PDFSensors (Basel)
December 2024
Department of Electrical, Computer and Biomedical Engineering, Toronto Metropolitan University, Toronto, ON M5B2K3, Canada.
Unmanned aerial vehicle (UAV)-enabled vehicular communications in the sixth generation (6G) are characterized by line-of-sight (LoS) and dynamically varying channel conditions. However, the presence of obstacles in the LoS path leads to shadowed fading environments. In UAV-assisted cellular vehicle-to-everything (C-V2X) communication, vehicle and UAV mobility and shadowing adversely impact latency and throughput.
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December 2024
Université de Lyon, UCBL1 Laboratoire Inter Universitaire de Biologie de la Motricité, EA 7424, 69100 Villeurbanne Cedex, France.
This study investigated muscle activation, shocks, and vibrations of the upper extremities during tennis serves between junior and adult tennis players. Thirty-five well-trained tennis players (15 juniors and 20 adults) performed 10 maximal successful tennis serves. Two triaxial accelerometers recorded the shock and vibration on the racket and the hand on the dominant side.
View Article and Find Full Text PDFNutrients
December 2024
Department of Pharmaceutical Botany, Faculty of Pharmacy, "Iuliu Hatieganu" University of Medicine and Pharmacy, 400337 Cluj-Napoca, Romania.
Micronutrient deficiencies (MNDs) are commonly reported after bariatric and metabolic surgery, including laparoscopic sleeve gastrectomy (LSG). Nevertheless, the micronutrient status changes over time and the influence of sex or initial body mass index (BMI) on these changes are less explored. This study aims to investigate the changes in micronutrient levels at 6 and 12 months after LSG and the potential influence of sex or baseline BMI (≥40 kg/m) on these changes in patients submitted to LSG.
View Article and Find Full Text PDFMicroorganisms
December 2024
Animal Production and Health Laboratory, Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Wagramer Strasse 5, P.O. Box 100, 1400 Vienna, Austria.
Abortion is one of the major causes of economic losses in livestock production worldwide. Because several factors can lead to abortion in cattle, sheep and goats, laboratory diagnosis, including the molecular detection of pathogens causing abortion, is often necessary. Bacterial zoonotic diseases such as brucellosis, coxiellosis, leptospirosis, and listeriosis have been implicated in livestock abortion, but they are under diagnosed and under-reported in most developing countries, including Botswana.
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