Ultrasonic Tomographic Imaging of an Encased, Highly Attenuating Solid Medium

Gan, Tat Hean; Hutchins, David A.; Billson, D.R.; Wong, Franklin

doi:10.1080/09349840109409693

Cited by 8 publications

(2 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Cross-correlation between the transmitted pulse and the received pulses results in a waveform containing the same time, amplitude, and spectral information as the received pulse (amplitude and frequency information is preserved). Pulse compression has recently been used with broadband air-coupled transducers, where energy transmission, SNR, and TOF accuracy are relatively low compared with conventional direct-coupled ultrasound (Gan et al 2001a;Gan et al 2001b;Gan et al 2004;Berriman et al 2005). Gan et al (2001a) found that pulse compression provided the air-coupled system with the ability to detect received pulses even when they were well below the noise floor due to the frequency-encoded transmitted pulse.…”

Section: Technical Backgroundmentioning

confidence: 99%

Density and Flow-Velocity Measurement Technology for Dredging Applications - Proof of Concept Study

Greenwood¹,

Tucker²,

Diaz³

2004

View full text Add to dashboard Cite

SummaryThe U.S. Army Corps of Engineers (USACoE) is searching for advanced technologies to provide physical property information about the dredge slurry traveling through the pipe in real-time, including density and the flow rate of the slurry. During the latter part of FY07, the USACoE funded a proof-ofconcept study at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington, to investigate potential technical solutions to this problem by evaluating the viability of a patented acoustic method for measuring density and the advanced measurement approach employed using pulsecompression acoustics. A trip to Coos Bay, Oregon, was taken by PNNL staff in mid-August to observe the operation of the USACoE dredger ship Essayons, which dredges sand from the ocean floor and to acquire samples of dredge slurry material extracted from the Bay for use in this study.PNNL staff conducted a proof-of-concept evaluation study on these dredge slurry samples to determine the viability for eventual design and testing of an ultrasonic density sensor and flow meter. Two sets of trials were conducted in this study: 1) basic ultrasonic property measurements and signal transmission trials in through-transmission mode using both mono-frequency tone-burst and pulsecompression approaches, and 2) real-time density measurements. This technical letter report provides a summary of the work conducted and the results obtained, and documents the conclusions and recommendations from this proof-of-concept evaluation.The Essayons employs both a radioactive density sensor and a sonic flow meter; both commercially available devices. The current density sensor operates and performs satisfactorily, but the USACoE wants to replace these technologies, especially the density sensor, due to cost, maintenance and security protocols, and paperwork issues associated with their use. The operation of the current sonic flow meter can be problematic.Although the ultrasonic pulse-compression technique could not penetrate the slurry generated in the laboratory setup, the results are still inconclusive due to the large amount of air introduced into the slurry as a result of the mixing process required for particle suspension. The conditions seen in the laboratory may not be representative of the slurry conditions generated in a pipe from dredge material pulled from the sea floor during routine dredging operations. It is anticipated that a pair of transducers placed on the outside of the dredge piping may demonstrate successful penetration of the slurry and allow for observable waveforms to accurately measure wave speed and relative attenuation, which are linearly related to the density of the slurry. This would allow for an alternate indication of specific gravity to the radiation density measurement currently used, and provide a means for measurement of flow rate using through-transmission methods. Further study onboard a dredging ship is recommended.Data were obtained using the PNNL ultrasonic density sensor for sand slurries having a density of 1.17 ...

show abstract

Section: Technical Backgroundmentioning

confidence: 99%

Density and Flow-Velocity Measurement Technology for Dredging Applications - Proof of Concept Study

Greenwood¹,

Tucker²,

Diaz³

2004

View full text Add to dashboard Cite

show abstract

“…Pulse compression has recently been used with broadband aircoupled transducers, where energy transmission, signal-to-noise ratio (SNR), and TOF accuracy are relatively low compared with conventional direct coupled ultrasound. 5,6,7,8 Gan et al 6 found that pulse compression provided the air-coupled system with the ability to detect received pulses even when they were well below the noise floor due to the frequency encoded transmitted pulse. In addition, they were able to resolve closelyspaced return echoes from various reflection sources with high accuracy, which was not possible with typical ultrasonic tone burst or square wave excitation technologies.…”

Section: Figure 1 the Container Screening Device (Csd) Alpha Unitmentioning

confidence: 99%

Through-container measurement of acoustic signatures for classification/discrimination of liquid explosives (LEs) and precursor threat liquids

et al. 2008

View full text Add to dashboard Cite

Work at the Pacific Northwest National Laboratory has demonstrated that ultrasonic property measurements can be effectively employed for the rapid and accurate classification/discrimination of liquids in small, carryon, standard "stream-of-commerce" containers. This paper focuses on a set of laboratory measurements acquired with the PNNL prototype device as applied to several types of liquids (including threat liquids and precursor chemicals) to the manufacture of LEs in small commercially available plastic containers.

show abstract

Nondestructive Testing

Brunner¹,

Hack²,

Neuenschwander³

2004

Encyclopedia of Polymer Science and Technology

View full text Add to dashboard Cite

Because of their unique properties, polymers and polymer–matrix composites pose both challenges and opportunities for nondestructive testing. The increasing use of these materials creates a demand for nondestructive verification of properties, structural integrity determination, or service‐life prediction. On the other hand, development of new nondestructive test methods, improved sensitivity, or faster data acquisition and analysis may allow for nondestructive testing applications that hitherto did not seem feasible or economical. This article provides a brief overview of established methods and emerging applications in nondestructive testing of polymers and polymer–matrix composites.

show abstract

Ultrasonic Tomographic Imaging of an Encased, Highly Attenuating Solid Medium

Cited by 8 publications

References 28 publications

Density and Flow-Velocity Measurement Technology for Dredging Applications - Proof of Concept Study

Density and Flow-Velocity Measurement Technology for Dredging Applications - Proof of Concept Study

Through-container measurement of acoustic signatures for classification/discrimination of liquid explosives (LEs) and precursor threat liquids

Nondestructive Testing

Contact Info

Product

Resources

About