In-situ pitting corrosion detection using high-frequency T(0,1) guided wave mode in gas distribution tubes at operating temperatures

2021 ◽  
Vol 6 (4) ◽  
pp. 247-256
Author(s):  
Aditya Chilukuri ◽  
Nishanth Raja ◽  
Krishnan Balasubramaniam
Keyword(s):  
Pitting Corrosion ◽  
High Frequency ◽  
Wave Mode ◽  
Guided Wave ◽  
Gas Distribution ◽  
Corrosion Detection ◽  
Operating Temperatures

High Frequency Guided Wave Propagation and Scattering in Silicon Wafers

2021 ◽  
pp. 1-18
Author(s):  
Jean-Luc Robyr ◽  
Mathieu Simon ◽  
Bernard Masserey ◽  
Paul Fromme
Keyword(s):  
Wave Propagation ◽  
Wave Field ◽  
High Frequency ◽  
Surface Defects ◽  
Wave Mode ◽  
Guided Wave ◽  
Silicon Wafers ◽  
Monocrystalline Silicon ◽  
Custom Made

Abstract Thin monocrystalline silicon wafers are employed for the manufacture of solar cells with high conversion efficiency. Micro-cracks can be induced by the wafer cutting process, leading to breakage of the fragile wafers. High frequency guided waves allow for the monitoring of wafers and detection and characterization of surface defects. The material anisotropy of the monocrystalline silicon leads to variations of the guided wave characteristics, depending on the guided wave mode and propagation direction relative to the crystal orientation. Selective excitation of the first anti-symmetric A0 wave mode at 5 MHz center frequency was achieved experimentally using a custom-made wedge transducer. Strong wave pulses with limited beam skewing and widening were measured using non-contact laser interferometer measurements. This allowed the accurate characterization of the Lamb wave propagation and scattering at small artificial surface defects with a size of less than 100 µm. The surface extent of the defects of varying size was characterized using an optical microscope. The scattered guided wave field was evaluated, and characteristic parameters extracted and correlated to the defect size, allowing in principle detection of small defects. Further investigations are required to explain the systematic asymmetry of the guided wave field in the vicinity of the indents.

scholarly journals Modeling and Experimentation of Thickness Mode E/M Impedance and Rayleigh Wave Propagation for Piezoelectric Wafer Active Sensors on Thick Plates

2014 ◽  
Author(s):  
Tuncay Kamas ◽  
Victor Giurgiutiu ◽  
Bin Lin
Keyword(s):  
Rayleigh Wave ◽  
High Frequency ◽  
Rayleigh Waves ◽  
Wave Mode ◽  
Elastic Plates ◽  
Active Sensors ◽  
Piezoelectric Wafer Active Sensors ◽  
Piezoelectric Wafer ◽  
Thickness Mode

This paper discusses theoretical and experimental analyses of the standing harmonic waves through the electro-mechanical impedance spectroscopy (EMIS) and guided surface acoustic waves (SAW) through the guided wave propagation (GWP) analyses. Both EMIS and GWP analyses have been carried out by utilizing piezoelectric wafer active sensors (PWAS) for in situ structural inspection. PWAS has recently been extensively employed in many applications such as nuclear-structural as well as aero-structural health monitoring and non-destructive evaluations (NDE). EMIS method is utilized for high frequency local modal sensing to determine the dynamic characteristics of PWAS bonded on nuclear-structural component for in-situ ultrasonics. Rayleigh waves a.k.a., SAW, were generated in relatively thick isotropic elastic plates. Rayleigh waves have the property of propagating close to the plate surface, with rapid attenuation with depth. The polarization of Rayleigh waves lies in a plane perpendicular to the surface so that the effective penetration depth is less than a wavelength. Rayleigh waves are a high frequency approximation of the first symmetric (S0) and anti-symmetric (A0) Lamb wave modes. As the frequency becomes very high the S0 and the A0 wave speeds coalesce, and both have the same value. This value is exactly the Rayleigh wave speed and becomes constant along the frequency. In the first part of the study, simplified theoretical constrained PWAS-EMIS model is briefly discussed in relatively high frequency range (in MHz order of magnitude) in terms of thickness mode. Analytical predictive thickness mode impedance simulations of PWAS bonded on plate-like host structures are presented in corresponding with the experiments. For the experimental analyses, PWAS transducers are affixed on isotropic elastic plates such as aluminum plate in relatively high thickness and on a rail I-beam. The extent of the agreement between the experimental and analytical EMIS analyses of PWAS in thickness mode is presented. The study is followed with GWP tests through the pitch-catch method. Rayleigh wave signal packets which are generated in the relatively thick plate and a rail I-beam in high frequency region are assessed along with the experimental thickness mode PWAS-EMIS results. The tuning curve of Rayleigh wave is determined to show the tuning effect of the structure thickness on producing a dominant Rayleigh wave mode. The significant usage of the tuned Rayleigh wave mode is essentially discussed for the applications in the in-situ inspection of relatively thick structures such as nuclear power plant structures. The paper ends with summary, conclusions and suggestions for future work.

Study of initial stages of pitting corrosion on aluminum in alkaline chloride solutions by in situ optical microscopy and methods of computer vision

2019 ◽  
pp. 33-44
Author(s):  
M.A. Maleeva ◽  
◽  
M.R. Enikeev ◽  
N.A. Gladkikh ◽  
M.A. Petrunin ◽  
...  
Keyword(s):  
Computer Vision ◽  
Optical Microscopy ◽  
Pitting Corrosion ◽  
Chloride Solutions

In-situ compaction and sintering of Al2O3 – GNP nanoparticles using a high-frequency induction system

2018 ◽  
Vol 60 (7-8) ◽  
pp. 727-732
Author(s):  
Uğur Çavdar ◽  
İ. Murat Kusoglu ◽  
Ayberk Altintas
Keyword(s):  
High Frequency ◽  
Induction System ◽  
High Frequency Induction

scholarly journals Location of agate geodes in Permian deposits of Simota gully using the GPR

2021 ◽  
Author(s):  
Michał Mierczak ◽  
Jerzy Karczewski
Keyword(s):  
Signal Processing ◽  
High Frequency ◽  
Electromagnetic Energy ◽  
Reflection Coefficients ◽  
Electric Permittivity ◽  
Pyroclastic Deposits ◽  
High Attenuation ◽  
Subsurface Geology ◽  
Study Test

AbstractThe article describes the establishment of the location of agate geodes using the GPR method in the area of the Simota gully (Lesser Poland Voivodeship). Agates (a multicolored variety of gemstone of chalcedony group) have multifaceted values that informed their study. Traditional methods of geode location are less reliable, hence the attempt to use the GPR method. Measurements were taken at two study test sites with subsurface geology of weathered melaphyre and pyroclastic deposits using a GPR system (ProEx). A high-frequency antenna (1.6 GHz) was used along with the pre-established profiles of lengths of 6-m and 10-cm intervals. Furthermore, simple soil tests using the soil sampler tool were made prior to the GPR measurement. The GPR results show significant high attenuation of the electromagnetic energy interpreted to be due to clay components of the regolith. Advanced signal processing procedures (such as the attribute of the signal) were used on the data for better enhancement that aided interpretation. Other anomalies depicted on the radargrams were thought to be the presence of roots, pieces of melaphyres-targeted agates. Furtherance to ascertain the reflection coefficients as recorded on the GPR data, in situ samples (root pieces, melaphyres, agates) taken were tested in the laboratory for electric permittivity property. Based on the interpretation results, several agate geodes were dug out from the ground.

Value of information of in situ inspections of mooring lines

2021 ◽  
pp. 1748006X2098740
Author(s):  
Jorge Mendoza ◽  
Jacopo Paglia ◽  
Jo Eidsvik ◽  
Jochen Köhler
Keyword(s):  
Pitting Corrosion ◽  
Value Of Information ◽  
Structural Reliability ◽  
Structural Safety ◽  
Statistical Dependence ◽  
Mooring System ◽  
Mooring Lines ◽  
Corrosion Condition ◽  
Chain Links

Mooring systems that are used to secure position keeping of floating offshore oil and gas facilities are subject to deterioration processes, such as pitting corrosion and fatigue crack growth. Past investigations show that pitting corrosion has a significant effect on reducing the fatigue resistance of mooring chain links. In situ inspections are essential to monitor the development of the corrosion condition of the components of mooring systems and ensure sufficient structural safety. Unfortunately, offshore inspection campaigns require large financial commitments. As a consequence, inspecting all structural components is unfeasible. This article proposes to use value of information analysis to rank identified inspection alternatives. A Bayesian Network is proposed to model the statistical dependence of the corrosion deterioration among chain links at different locations of the mooring system. This is used to efficiently update the estimation of the corrosion condition of the complete mooring system given evidence from local observations and to reassess the structural reliability of the system. A case study is presented to illustrate the application of the framework.

Design of in situ sample rotation mechanism for angle-dependent study of cantilever-detected high-frequency ESR

2013 ◽  
Vol 227 ◽  
pp. 9-13 ◽  
Author(s):  
E. Ohmichi ◽  
S. Hirano ◽  
H. Ohta
Keyword(s):  
High Frequency ◽  
Sample Rotation

scholarly journals Mechanism of acetylcholine-induced Ca2+ oscillation with high frequency in individual endothelial cells in rat aorta in situ

1998 ◽  
Vol 76 ◽  
pp. 149
Author(s):  
Gousei Lee ◽  
Hisayuki Qhata ◽  
Yosuke Ujike ◽  
Chieko Yanagi ◽  
Kazutaka Momose
Keyword(s):  
Endothelial Cells ◽  
High Frequency ◽  
Rat Aorta
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