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

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.

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

Volume 1: Pipeline and Facilities Integrity ◽

10.1115/ipc2018-78704 ◽

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.

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Screening in Child Health Care: Where Are We Now and Where Are We Going?

PEDIATRICS ◽

10.1542/peds.54.5.631 ◽

1974 ◽

Vol 54 (5) ◽

pp. 631-640

Author(s):

A. Frederick North

Keyword(s):

Neonatal Screening ◽

Low Frequency ◽

Cost Effective ◽

Direct Costs ◽

Screening Tests ◽

Child Health Care ◽

False Negatives ◽

Future Directions ◽

Screening Programs ◽

The Cost

The preceding papers1-7 in this symposium discuss criteria for evaluating screening tests and screening programs and demonstrate how these criteria can be applied to several screening techniques of particular current interest. This paper will briefly review how a number of procedures measure up to the suggested criteria for screening tests and suggest some future directions which must be pursued if screening is to be based on science rather than on polemic. WHERE ARE WE NOW? Table I lists a number of diseases, functions and tests which have been considered to be of use in screening. For each of these it also gives my own estimate of how well each disease meets the criteria listed by Frankenburg2 and how well the available tests meet his criteria for effectiveness, direct costs, costs of false positives, and costs of false negatives. In the following paragraphs some of the considerations which led to these judgments are discussed. Phenyketonuria Despite its low frequency, the cost effectiveness of screening for PKU is well demonstrated, tests are adequately sensitive and specific, and with expert management the potentially high costs of false-positive tests can largely be eliminated.3 Galactosemia Though even rarer than PKU, current methods make routine neonatal screening both feasible and cost effective, provided that the test is combined with routine PKU screening.8 Other Inborn Metabolic Errors With the kind of regionalized facilities and planning discussed by Scriver,3 testing for these diseases can be added to routine neonatal screening at very little additional cost. Some of them lend themselves to effective early treatment; with others, genetic counsulling is the only currently available useful intervention.

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CAD Of Anticorrosive Protection Of Steel Structures

Promyshlennoe i Grazhdanskoe Stroitel stvo ◽

10.33622/0869-7019.2019.09.18-23 ◽

2019 ◽

pp. 18-23

Keyword(s):

Protective Coating ◽

Computer Aided Design ◽

Steel Structures ◽

Cost Effective ◽

Operating Conditions ◽

Computational Tool ◽

Protection Method ◽

Cost Effective Method ◽

The Cost ◽

Aided Design

The choice of cost-effective method of anticorrosive protection of steel structures is an urgent and time consuming task, considering the significant number of protection ways, differing from each other in the complex of technological, physical, chemical and economic characteristics. To reduce the complexity of solving this problem, the author proposes a computational tool that can be considered as a subsystem of computer-aided design and used at the stage of variant and detailed design of steel structures. As a criterion of the effectiveness of the anti-corrosion protection method, the cost of the protective coating during the service life is accepted. The analysis of existing methods of steel protection against corrosion is performed, the possibility of their use for the protection of the most common steel structures is established, as well as the estimated period of effective operation of the coating. The developed computational tool makes it possible to choose the best method of protection of steel structures against corrosion, taking into account the operating conditions of the protected structure and the possibility of using a protective coating.

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Infrared Emission Spectroscopy as a Reliability Tool

ISTFA 1999: Conference Proceedings from the 25th International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa1999p0077 ◽

1999 ◽

Author(s):

Q. Kim ◽

S. Kayali

Keyword(s):

Spatial Resolution ◽

Emission Spectroscopy ◽

Hot Spot ◽

Cost Effective ◽

Infrared Emission ◽

Test System ◽

Operating Conditions ◽

Yield Enhancement ◽

Infrared Emission Spectroscopy ◽

Channel Temperature

Abstract In this paper, we report on a non-destructive technique, based on IR emission spectroscopy, for measuring the temperature of a hot spot in the gate channel of a GaAs metal/semiconductor field effect transistor (MESFET). A submicron-size He-Ne laser provides the local excitation of the gate channel and the emitted photons are collected by a spectrophotometer. Given the state of our experimental test system, we estimate a spectral resolution of approximately 0.1 Angstroms and a spatial resolution of approximately 0.9 μm, which is up to 100 times finer spatial resolution than can be obtained using the best available passive IR systems. The temperature resolution (<0.02 K/μm in our case) is dependent upon the spectrometer used and can be further improved. This novel technique can be used to estimate device lifetimes for critical applications and measure the channel temperature of devices under actual operating conditions. Another potential use is cost-effective prescreening for determining the 'hot spot' channel temperature of devices under normal operating conditions, which can further improve device design, yield enhancement, and reliable operation. Results are shown for both a powered and unpowered MESFET, demonstrating the strength of our infrared emission spectroscopy technique as a reliability tool.

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