Low‐frequency search unit for ultrasonic testing of concrete

1988 ◽  
Vol 84 (S1) ◽  
pp. S72-S72
Author(s):  
Kanji Imoto ◽  
Koji Ohta ◽  
Takeharu Watanabe
Keyword(s):  
Ultrasonic Testing ◽  
Low Frequency ◽  
Frequency Search

scholarly journals KIC 8975515: A fast-rotating (γ Dor – δ Sct) hybrid star with Rossby modes and a slower δ Sct companion in a long-period orbit

2020 ◽  
Vol 638 ◽  
pp. A57
Author(s):  
A. Samadi-Ghadim ◽  
P. Lampens ◽  
D. M. Jassur ◽  
P. Jofré
Keyword(s):  
Fourier Spectrum ◽  
Low Frequency ◽  
Careful Analysis ◽  
Rotational Frequency ◽  
Echelle Spectrograph ◽  
Mean Values ◽  
Frequency Regime ◽  
Rotating Star ◽  
Frequency Search ◽  
Fast Rotating

Aims. KIC 8975515 is a double-lined spectroscopic binary system with hybrid nature. Regular monitoring with the échelle spectrograph HERMES show that both components have matching atmospheric properties (Teff ∼ 7400 K), and that one of them is a fast rotator (v sin i = 162 versus 32 km s−1). Our aim is to study the Kepler light curve in order to determine the frequencies of the pulsations, to search for regular spacing patterns in the Fourier spectrum, if any, and to discuss their origin in the context of binarity and fast rotation. Methods. In this paper, we study the properties of the stellar pulsations based on a careful analysis of the Fourier spectrum. This was done by performing repeated frequency-search analyses with successive prewhitenings of all the significant frequencies detected in the spectrum. Moreover, we searched for regular period spacing among the g modes as well as frequency splitting among the g and p modes in frequency. Results. In the low-frequency regime, one series of prograde g modes and four series of retrograde r modes, were detected. The r modes are well-distributed with respect to the harmonics of the rotational frequency of the fast-rotating star frot = 1.647 d−1. The dominant g mode is f2 = 2.37 d−1. The strongest p mode is f1 = 13.97 d−1. We identified two multiplets of regularly split p modes with the mean values of 0.42 d−1 and 1.65 d−1. In addition, we also identified a few incidences of mode coupling (between f1 and a g or r mode). Conclusions. We detected five series of retrograde r and prograde g modes as well as two multiplets of p modes with rotational frequency splitttings related to both components of KIC 8975515. We identified the fast-rotating component as a hybrid pulsator with r modes, and the slowly-rotating component as a δ Sct pulsator.

scholarly journals Low-frequency Ultrasonic Testing Of Process Piping By Guided Waves

2016 ◽  
Vol 2016 (1) ◽  
pp. 7-13
Author(s):  
V.A. Troitskii ◽  
◽  
M.N. Karmanov ◽  
V.M. Gorbik ◽  
N.V. Lukashev ◽  
...  
Keyword(s):  
Ultrasonic Testing ◽  
Guided Waves ◽  
Low Frequency ◽  
Process Piping

Ultrasonic NDE Technology Comparison for Measurement of Long Seam Weld Anomalies in Low Frequency Electric Resistance Welded Pipe

2018 ◽  
Author(s):  
Luis Torres ◽  
Matthew Fowler ◽  
Jason Bergman
Keyword(s):  
Ultrasonic Testing ◽  
Low Frequency ◽  
Management Approach ◽  
Electric Resistance ◽  
Seam Weld ◽  
Tool Performance ◽  
Ultrasonic Nde ◽  
Welded Pipe ◽  
Continuous Technology ◽  
Non Destructive

In the pipeline industry, a widely accepted methodology for integrity crack management involves running ultrasonic In-Line Inspection (ILI) technologies. After an ILI tool run is completed, the performance of the tool is typically validated by excavating the pipeline and conducting in-the-ditch investigations. Ultrasonic Non-Destructive Evaluation (NDE) techniques are used in the field to characterize and measure crack-like features. These in-the-ditch measurements are compared back to ILI results in order to validate tool performance and drive continuous technology improvements. Since validation of the ILI tool relies on NDE measurements, acquiring accurate and representative data in the field is a critical step in this integrity crack management approach. Achieving an accurate field inspection comes with its challenges, some of which relate to complex long seam weld conditions present in older vintage pipelines including: weld misalignment, weld trim issues, and dense populations of manufacturing anomalies. In order to better understand the challenges associated with complex long seam weld conditions, an evaluation and comparison of the performance of NDE technologies currently available was conducted. In this study, a portion of a Canadian pipeline with complex long seam weld conditions was cut-out and removed from service. Multiple NDE crack inspection technologies and methods from three different vendors were used to assess the condition of the long seam weld. Conventional Ultrasonic Testing (UT), Phased Array Ultrasonic Testing (PAUT), Time of Flight Diffraction (TOFD), and variations of Full Matrix Capture Ultrasonic Testing (FMCUT) were used to assess the long seam weld and their results were compared. The performance of all NDE technologies is baselined by comparing them with destructive examination of sections of the long seam weld. The newer NDE assessment methodologies were shown to be consistently more accurate in characterizing long seam features.

scholarly journals Review of Current Guided Wave Ultrasonic Testing (GWUT) Limitations and Future Directions

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 811
Author(s):  
Samuel Chukwuemeka Olisa ◽  
Muhammad A. Khan ◽  
Andrew Starr
Keyword(s):  
Ultrasonic Testing ◽  
Low Frequency ◽  
Cost Effective ◽  
Guided Wave ◽  
Operating Conditions ◽  
Damage Effect ◽  
Temperature Influence ◽  
Future Directions ◽  
Metallic Structures ◽  
Non Destructive

Damage is an inevitable occurrence in metallic structures and when unchecked could result in a catastrophic breakdown of structural assets. Non-destructive evaluation (NDE) is adopted in industries for assessment and health inspection of structural assets. Prominent among the NDE techniques is guided wave ultrasonic testing (GWUT). This method is cost-effective and possesses an enormous capability for long-range inspection of corroded structures, detection of sundries of crack and other metallic damage structures at low frequency and energy attenuation. However, the parametric features of the GWUT are affected by structural and environmental operating conditions and result in masking damage signal. Most studies focused on identifying individual damage under varying conditions while combined damage phenomena can coexist in structure and hasten its deterioration. Hence, it is an impending task to study the effect of combined damage on a structure under varying conditions and correlate it with GWUT parametric features. In this respect, this work reviewed the literature on UGWs, damage inspection, severity, temperature influence on the guided wave and parametric characteristics of the inspecting wave. The review is limited to the piezoelectric transduction unit. It was keenly observed that no significant work had been done to correlate the parametric feature of GWUT with combined damage effect under varying conditions. It is therefore proposed to investigate this impending task.

Analytical Optimization of Low-Frequency Search Coil Magnetometers

2012 ◽  
Vol 12 (8) ◽  
pp. 2719-2723 ◽  
Author(s):  
A. Grosz ◽  
E. Paperno
Keyword(s):  
Low Frequency ◽  
Search Coil ◽  
Frequency Search

Air-Coupled Ultrasound: A New Paradigm in NDE

2007 ◽  
Author(s):  
Vinay Dayal ◽  
David K. Hsu ◽  
Adam H. Kite
Keyword(s):  
Ultrasonic Testing ◽  
Composite Structures ◽  
Low Frequency ◽  
New Paradigm ◽  
Very Low Frequency ◽  
Ultrasonic Investigation

In any ultrasonic investigation, the contact between the transducer and the object has always been a source of problem. With the introduction of the air-coupled ultrasonic probes the couplant is totally eliminated. The limitation of these probes is that they are of very low frequency and as a result they bring their set of restrictions. We present here a couple of results of our investigations of composite structures with air-coupled transducers. The resonance of structures is an important factor which is able to explain observations of air-coupled ultrasonic testing.

Simplified Design of a Low Frequency Search Coil Magnetometer

2019 ◽  
Author(s):  
Madalina BUCUR ◽  
Georgiana ROSU ◽  
Adelina BORDIANU ◽  
Lucian PETRESCU ◽  
Valentin IONITA ◽  
...  
Keyword(s):  
Low Frequency ◽  
Search Coil ◽  
Frequency Search

scholarly journals Nedestruktivní zkoušení trubek pomocí metody LFET, UT a ET / Nondestructive testing of tubes using the LFET, UT and ET methods

2015 ◽  
Vol 59 (3) ◽  
pp. 77-80
Author(s):  
M. Mráz
Keyword(s):  
Nondestructive Testing ◽  
Ultrasonic Testing ◽  
Low Frequency ◽  
Electromagnetic Testing

Dlouhodobým cílem programu řízení životnosti tlakových částí kotlů je eliminace poruchových odstávek a bezpečné provozování těchto zařízení. K detekci kritických blokací ohybů trubek odloupnutými částicemi epitaktické vrstvy byla ve spolupráci s EPRI vybrána metoda LFET (Low Frequency Electromagnetic Testing) a pro měření celkové tloušťky oxidické vrstvy metoda UT (Ultrasonic Testing), které nacházejí uplatnění zejména v USA. Ultrazvukový tloušťkoměr je použitelný pouze pro feritické materiály. Upravená metoda vířivých proudů (ET) bude sloužit ke stanovení tloušťky epitaktické vrstvy na austenitických ocelích.

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