Results 11 to 20 of about 3,001,234 (205)
Air-Coupled Photoacoustic Detection of Airborne Particulates. [PDF]
Int J Thermophys, 2023 <p>In this study, we present a novel method to detect airborne particulates using air-coupled photoacoustics, with a goal toward detecting viral content in respiratory droplets. The peak photoacoustic frequency emitted from micrometer-sized particulates is over 1000 MHz, but at this frequency, the signals are highly attenuated in air ...
Strohm EM +4 more
europepmc +3 more sources
Ultrasonic air-coupled capacitive arrays [PDF]
A model is developed which is capable of predicting the pressure field of a rectangular source, as measured by a finite-sized receiver. This novel method treats the problem in a new way, which allows an integration to be performed over the area of the ...
Neild, Adrian
core +1 more source
Fabrication and Modeling of Matching System for Air-Coupled Transducer. [PDF]
Micromachines (Basel), 2022 The tremendous acoustic impedance difference between the piezoelectric composite and air prevents the ultrasonic transition, resulting in low amplitude for the received signal for the composite defect detection using an air-coupled transducer. The matching system, which includes the matching layers and bonding layers attached to the piezoelectric ...
Zhou J, Bai J, Liu Y.
europepmc +4 more sources
Theory of Air-Coupled Flexural Waves [PDF]
Journal of Applied Physics, 1951 The theory of air-coupled flexural waves in a floating ice sheet is derived for the case of an impulsive point source situated either in the air or in the water. It is found that new branches are introduced to the dispersion curve of flexural waves as a result of coupling to compressional waves in the atmosphere. Experimental data are briefly reviewed.
Press, Frank, Ewing, Maurice
openaire +3 more sources
Phased array probes for air-coupled ultrasonic testing based on cellular polymer
Research and Review Journal of Nondestructive Testing, 2023 Air-coupled ultrasonic testing is an established alternative to conventional ultrasonic methods for testing of light-weight components in aerospace and automotive industry.
Mate Gaal +6 more
doaj +1 more source
Air-Coupled Ultrasonic Ferroelectret Receiver with Additional DC Voltage
Proceedings, 2017 Highly sensitive air-coupled ultrasonic sensors are essential for various applications such as testing of composite materials. One of the major challenges for the development of air-coupled ultrasonic sensors is the impedance matching to air.
Mate Gaal +3 more
doaj +1 more source
Application of Micro-Electro-Mechanical Sensors Contactless NDT of Concrete Structures
Sensors, 2015 The utility of micro-electro-mechanical sensors (MEMS) for application in air-coupled (contactless or noncontact) sensing to concrete nondestructive testing (NDT) is studied in this paper.
Suyun Ham, John S. Popovics
doaj +1 more source
ISPRS International Journal of Geo-Information, 2015 Spectral Analysis of Surface Wave (SASW) is widely used in nondestructive subsurface profiling for geological sites. The air-coupled SASW is an extension from conventional SASW methods by replacing ground-mounted accelerometers with non-contact ...
Yifeng Lu +3 more
doaj +1 more source
Comparative Study of Coupling Techniques in Lamb Wave Testing of Metallic and Cementitious Plates
Sensors, 2019 Lamb waves have emerged as a valuable tool to examine long plate-like structures in a faster way compared to conventional bulk wave techniques, which make them attractive in non-destructive testing.
Santiago Vázquez +5 more
doaj +1 more source
Contactless Ultrasonic Wavefield Imaging to Visualize Near-Surface Damage in Concrete Elements
Applied Sciences, 2019 We present work to detect and visualize near-surface damage in concrete using contactless ultrasonic wavefield imaging technology. A fully contactless ultrasonic scanning system that utilizes a micro-electro-mechanical systems (MEMS) ultrasonic ...
Homin Song, John S. Popovics
doaj +1 more source