Time of Flight Extraction of Dispersive Lamb Wave by Ridge Analysis

2018 ◽  
Author(s):  
Zhe Wang ◽  
Songling Huang ◽  
Qing Wang ◽  
Shen Wang ◽  
Wei Zhao
Keyword(s):  
Lamb Wave ◽  
Time Of Flight

Lamb Wave Inspection of Concrete Beams

1999 ◽  
Author(s):  
Y. C. Jung ◽  
T. Kundu ◽  
M. Ehsani
Keyword(s):  
Lamb Wave ◽  
Concrete Beams ◽  
Lamb Waves ◽  
Time Of Flight ◽  
Signal Amplitude ◽  
Internal Defects ◽  
Longitudinal Waves ◽  
Ultrasonic Methods ◽  
Wave Technique ◽  
Flight Measurements

Abstract The feasibility of detecting defects in concrete beams using Lamb waves is investigated in this paper. The traditional ultrasonic methods for inspecting defects in concrete use the reflection and scattering of longitudinal waves by internal defects. Signal amplitude and time of flight measurements provide information about the internal defects in concrete. However, these methods are time consuming and often fail to detect honeycombs, closed cracks and small defects. In this paper the potential of the Lamb wave technique to detect those defects in large concrete beams is investigated. The Lamb wave technique is found to be reliable for detecting such defects in concrete beams.

A time-of-flight revising approach to improve the image quality of Lamb wave tomography for the detection of defects in composite panels

2018 ◽  
Vol 25 (3) ◽  
pp. 587-592 ◽  
Author(s):  
Liang Chen ◽  
Qiang Xiao ◽  
Wei Liang ◽  
Jingxian Hong ◽  
Xingjiang Zou
Keyword(s):  
Composite Materials ◽  
Lamb Wave ◽  
Structural Integrity ◽  
Time Of Flight ◽  
Visual Quality ◽  
Reconstruction Algorithm ◽  
Tomographic Images ◽  
Data Revision ◽  
Wave Tomography

Abstract Lamb wave tomography can be used to evaluate structural integrity. The time-of-flight (TOF) data are usually recorded as input to the reconstruction algorithm. For composite materials, TOF estimation is complicated due to their anisotropy. To reduce the effects of anisotropy on image reconstruction, the TOF data of flawed plates are revised according to baseline data obtained from an unflawed plate. Tomographic images are reconstructed using the original and revised TOF data, respectively. Results show that images reconstructed using the revised TOF data have better visual quality and that TOF data revision can substantially reduce the artifacts resulting from anisotropy in defect detection of composite materials.

Applications of Time-OF-Flight Secondary Ion Mass Spectrometry (TOF-SIMS)

1990 ◽  
Vol 48 (2) ◽  
pp. 308-309
Author(s):  
Bruno Schueler ◽  
Robert W. Odom
Keyword(s):  
Mass Spectrometry ◽  
Secondary Ion Mass Spectrometry ◽  
Structural Information ◽  
Time Of Flight ◽  
Biological Tissues ◽  
Polymer Surfaces ◽  
Tof Sims ◽  
Secondary Ions ◽  
Ion Mass Spectrometry ◽  
Secondary Ion

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) provides unique capabilities for elemental and molecular compositional analysis of a wide variety of surfaces. This relatively new technique is finding increasing applications in analyses concerned with determining the chemical composition of various polymer surfaces, identifying the composition of organic and inorganic residues on surfaces and the localization of molecular or structurally significant secondary ions signals from biological tissues. TOF-SIMS analyses are typically performed under low primary ion dose (static SIMS) conditions and hence the secondary ions formed often contain significant structural information.This paper will present an overview of current TOF-SIMS instrumentation with particular emphasis on the stigmatic imaging ion microscope developed in the authors’ laboratory. This discussion will be followed by a presentation of several useful applications of the technique for the characterization of polymer surfaces and biological tissues specimens. Particular attention in these applications will focus on how the analytical problem impacts the performance requirements of the mass spectrometer and vice-versa.

Lamb Wave Tomography and Its Application in Pipe Erosion/Corrosion Monitoring

1996 ◽  
Vol 8 (1) ◽  
pp. 189-197
Author(s):  
J. Pei ◽  
M. I. Yousuf ◽  
F. L. Degertekin ◽  
B. V. Honein ◽  
B. T. Khuri-Yakub
Keyword(s):  
Lamb Wave ◽  
Corrosion Monitoring ◽  
Erosion Corrosion ◽  
Wave Tomography

Assessment of extracranial-intracranial bypass in Moyamoya disease using 3T time-of-flight MR angiography: Comparison with CT angiography

VASA ◽  
2014 ◽  
Vol 43 (4) ◽  
pp. 278-283 ◽  
Author(s):  
Qian Chen ◽  
Rongfeng Qi ◽  
Xiaoqing Cheng ◽  
Changsheng Zhou ◽  
Song Luo ◽  
...  
Keyword(s):  
Image Quality ◽  
Moyamoya Disease ◽  
Mr Angiography ◽  
Time Of Flight ◽  
Consecutive Series ◽  
Tof Mra ◽  
Bypass Patency ◽  
Significant Difference ◽  
Contrast Technique ◽  
Vessel Integrity

Background: To evaluate the value of time-of-flight MR angiography (TOF MRA) for the assessment of extracranial-intracranial (EC-IC) bypass in Moyamoya disease in comparison with computed tomography angiography (CTA). Patients and methods: A consecutive series of 23 patients with Moyamoya disease were analyzed retrospectively. Twenty three patients underwent 25 procedures of extracranial-intracranial bypass. Cranial CTA was performed within one week after the surgery to assess bypass patency. Then TOF MRA was scanned within 24 h after CTA on a 3T MRI system. Using 5-point scales (0 = poor to 4 = excellent), two radiologists rated the image quality and vessel integrity of bypass for three segments (extracranial, trepanation, intracranial). Results: Image quality was high in both CTA and TOF MRA (mean quality score 3.84 ± 0.37 and 3.8 ± 0.41), without statistical difference (p = 0.66). Mean scores of TOF MRA with respect to bypass visualization were higher than CTA in the intracranial segment (p = 0.026). No significant difference of bypass visualization regarding the extracranial and trepanation segments was found between TOF MRA and CTA (p = 0.66 and p = 0.34, respectively). For the trepanation segment, TOF MRA showed pseudo lesions in 2 of all 25 cases. Conclusions: 3T TOF MRA, a non-contrast technique not exposing the patients to radiation, proved to be at least equal to CTA for the assessment of EC-IC bypass, and even superior to CTA with respect to the intracranial segment. In addition, readers should be aware of a potential overestimation showing focal pseudo lesions of the bypass at the trepanation segment in TOF MRA.

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