Applications of Centimetric Radio Waves in Nondestructive Testing

2009 ◽  
pp. 3-3-22
Keyword(s):  
Nondestructive Testing ◽  
Radio Waves

Nondestructive Testing in Asphalt Pavements Using Ground Penetrating Radar (GPR)

2013 ◽  
Vol 303-306 ◽  
pp. 525-528 ◽  
Author(s):  
Maria Teresa Françoso ◽  
Carolina Oyama Mota ◽  
Tadeu Rosanti Sugahara Medeiros Lima ◽  
Creso De Franco Peixoto
Keyword(s):  
Nondestructive Testing ◽  
Real Time ◽  
Ground Penetrating Radar ◽  
Asphalt Pavements ◽  
State University ◽  
Radio Waves ◽  
Specialized Software ◽  
Ground Penetrating ◽  
Non Destructive

This paper presents the results of using the system GPR (Ground Penetrating Radar), as an alternative that uses radio waves at frequencies from 10 to 2500 MHz to get data that enable non-destructive conduct inspections of underground or concrete structures in real time. The research aims to investigate asphalt pavements, analyzing the variations in the responses, which can reveal the presence of pathologies or defects. A case study was made acquiring data, at the State University of Campinas - UNICAMP, in Campinas – SP – Brazil, with antennae 270 and 1600 MHz, in pavements with visible defects of patching and alligator cracks, initially with the dry structure and later, wet. The results were processed in specialized software (Radan 7.0) to generate terrain profiles. The GPR showed effective when there is a change in material employed as in the case of patching, because it was possible to detect layers compromised by intensive request of traffic, the start and end of application of the patching and even deformations in the new layer. In contrast, the alligator cracking did not reach the same result, not presenting accuracy in recognizing the defect. The extent of defect was the only well defined feature in the images.

Radio Measurements of Coronal Magnetic Fields

1994 ◽  
Vol 144 ◽  
pp. 21-28 ◽  
Author(s):  
G. B. Gelfreikh
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Solar Corona ◽  
Active Regions ◽  
High Sensitivity ◽  
Coronal Magnetic Field ◽  
Transverse Magnetic ◽  
Radio Sources ◽  
Radio Waves ◽  
Solar Active Regions

AbstractA review of methods of measuring magnetic fields in the solar corona using spectral-polarization observations at microwaves with high spatial resolution is presented. The methods are based on the theory of thermal bremsstrahlung, thermal cyclotron emission, propagation of radio waves in quasi-transverse magnetic field and Faraday rotation of the plane of polarization. The most explicit program of measurements of magnetic fields in the atmosphere of solar active regions has been carried out using radio observations performed on the large reflector radio telescope of the Russian Academy of Sciences — RATAN-600. This proved possible due to good wavelength coverage, multichannel spectrographs observations and high sensitivity to polarization of the instrument. Besides direct measurements of the strength of the magnetic fields in some cases the peculiar parameters of radio sources, such as very steep spectra and high brightness temperatures provide some information on a very complicated local structure of the coronal magnetic field. Of special interest are the results found from combined RATAN-600 and large antennas of aperture synthesis (VLA and WSRT), the latter giving more detailed information on twodimensional structure of radio sources. The bulk of the data obtained allows us to investigate themagnetospheresof the solar active regions as the space in the solar corona where the structures and physical processes are controlled both by the photospheric/underphotospheric currents and surrounding “quiet” corona.

Radio Waves Kill Insect Pests

1933 ◽  
Vol 148 (5) ◽  
pp. 272-273 ◽  
Author(s):  
J. H. Davis
Keyword(s):  
Insect Pests ◽  
Radio Waves

Ultra Short Baseline (USBL) Calibration for Positioning of Underwater Objects

2019 ◽  
Vol 2 (2) ◽  
pp. 73-85
Author(s):  
Bagus Septyanto ◽  
Dian Nurdiana ◽  
Sitti Ahmiatri Saptari
Keyword(s):  
Acoustic Wave ◽  
Scale Factor ◽  
Positioning System ◽  
Radio Waves ◽  
Short Baseline ◽  
Error Angle ◽  
Satellite Navigation System ◽  
The Earth ◽  
Underwater Positioning ◽  
Radio Signals

In general, surface positioning using a global satellite navigation system (GNSS). Many satellites transmit radio signals to the surface of the earth and it was detected by receiver sensors into a function of position and time. Radio waves really bad when spreading in water. So, the underwater positioning uses acoustic wave. One type of underwater positioning is USBL. USBL is a positioning system based on measuring the distance and angle. Based on distance and angle, the position of the target in cartesian coordinates can be calculated. In practice, the effect of ship movement is one of the factors that determine the accuracy of the USBL system. Ship movements like a pitch, roll, and orientation that are not defined by the receiver could changes the position of the target in X, Y and Z coordinates. USBL calibration is performed to detect an error angle. USBL calibration is done by two methods. In USBL calibration Single Position obtained orientation correction value is 1.13 ̊ and a scale factor is 0.99025. For USBL Quadrant calibration, pitch correction values is -1.05, Roll -0.02 ̊, Orientation 6.82 ̊ and scale factor 0.9934 are obtained. The quadrant calibration results deccrease the level of error position to 0.276 - 0.289m at a depth of 89m and 0.432m - 0.644m at a depth of 76m

Evaluation of Spatial Resolution of Nondestructive Testing of Thermal Barrier Coating by Terahertz Imaging

2012 ◽  
Vol 132 (10) ◽  
pp. 864-870
Author(s):  
Tetsuo Fukuchi ◽  
Norikazu Fuse ◽  
Mitsutoshi Okada ◽  
Tomoharu Fujii ◽  
Maya Mizuno ◽  
...  
Keyword(s):  
Nondestructive Testing ◽  
Thermal Barrier Coating ◽  
Spatial Resolution ◽  
Terahertz Imaging ◽  
Thermal Barrier ◽  
Barrier Coating

Nondestructive Testing using Terahertz Waves

2015 ◽  
Vol 135 (11) ◽  
pp. 647-650 ◽  
Author(s):  
Tetsuo Fukuchi ◽  
Norikazu Fuse ◽  
Maya Mizuno ◽  
Kaori Fukunaga
Keyword(s):  
Nondestructive Testing ◽  
Terahertz Waves
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