scholarly journals A Double Transducer for High Precision Ultrasonic Time-Domain Reflectometry Measurements

Sensors ◽  
2015 ◽  
Vol 15 (7) ◽  
pp. 15090-15100 ◽  
Author(s):  
Sam Stade ◽  
Tuomas Hakkarainen ◽  
Mari Kallioinen ◽  
Mika Mänttäri ◽  
Tuure Tuuva
Keyword(s):  
High Precision ◽  
Time Domain ◽  
Time Domain Reflectometry ◽  
Ultrasonic Time

Monitoring membrane biofouling via ultrasonic time-domain reflectometry enhanced by silica dosing

2013 ◽  
Vol 428 ◽  
pp. 24-37 ◽  
Author(s):  
S.T.V. Sim ◽  
S.R. Suwarno ◽  
T.H. Chong ◽  
W.B. Krantz ◽  
A.G. Fane
Keyword(s):  
Time Domain ◽  
Time Domain Reflectometry ◽  
Membrane Biofouling ◽  
Ultrasonic Time

Active Scour Monitoring using Ultrasonic Time Domain Reflectometry of Buried Slender Sensors

2021 ◽  
Author(s):  
Morgan Funderburk ◽  
Jamie Tran ◽  
Michael Todd ◽  
Anton Netchaev ◽  
Kenneth J Loh
Keyword(s):  
Time Domain ◽  
Extreme Event ◽  
Lamb Waves ◽  
The United States ◽  
External Pressure ◽  
Time Domain Reflectometry ◽  
Scour Monitoring ◽  
Ultrasonic Time ◽  
Bridge Failure ◽  
Soil Interface

Abstract Local scour is a growing cause of bridge failure in the United States and around the world. In the next century, the effects of climate changes will make more bridges susceptible to scour failure more than ever before. This study aims to harness the spatially continuous monitoring capabilities of ultrasonic time-domain reflectometry to detect a soil interface for the purposes of scour monitoring. In this study, a long, slender plate is coupled with two flexible piezoelectric devices that propagate Lamb waves along the length of the plate to form the scour sensor. The sensor was tested for sensitivity to external pressure using metal weights, and was able to detect the position of the pressure up at a length of up to ~ 20 feet. The sensor was tested under simulated scour conditions, being buried in sand at various depths. The results show that the Lamb wave scour sensor is capable of reliably detecting a soil interface at 1 ft intervals. The scour sensor was also able to detect uncompacted soil interfaces, which is important considering the issue of scour hole refill following an extreme event.

In situ monitoring of wastewater biofilm formation process via ultrasonic time domain reflectometry (UTDR)

2018 ◽  
Vol 334 ◽  
pp. 2134-2141 ◽  
Author(s):  
Jinfeng Wang ◽  
Hongqiang Ren ◽  
Xianhui Li ◽  
Jianxin Li ◽  
Lili Ding ◽  
...  
Keyword(s):  
Time Domain ◽  
Formation Process ◽  
Biofilm Formation ◽  
Time Domain Reflectometry ◽  
In Situ Monitoring ◽  
Ultrasonic Time

Monitoring of CaSO4 deposition behaviors on biofilm during nanofiltration via ultrasonic time-domain reflectometry (UTDR)

2010 ◽  
Vol 61 (11) ◽  
pp. 2853-2861 ◽  
Author(s):  
Y. L. Hou ◽  
J. X. Li ◽  
Y. N. Gao ◽  
X. C. Xu ◽  
Y. Cai ◽  
...  
Keyword(s):  
Time Domain ◽  
Pressure Effect ◽  
Membrane Surface ◽  
Time Domain Reflectometry ◽  
Sem Images ◽  
Differential Signal ◽  
Flux Decline ◽  
Ultrasonic Time ◽  
Ultrasonic Measurements ◽  
Non Destructive

The ultrasonic time-domain reflectometry (UTDR) as a non-destructive real-time method was employed to monitor the CaSO4 deposition behaviors on biofilm during nanofiltration (NF). Two parallel experiments were performed to compare the different behaviors of CaSO4 deposition with and without biofilm on the membrane. Results showed that the flux decline during combined fouling was slower than that in case of CaSO4 fouling alone. The Ca2 +  rejection obtained with biofilm was higher than that without. A larger acoustic differential signal obtained by UTDR in the combined fouling revealed a denser and thicker layer formed on the membrane surface. Furthermore, the amount of CaSO4 deposition on the biofouled membrane was more than that on non-biofouled membrane as a result of microorganisms as crystal nucleus to induce CaSO4 crystallization and deposition. SEM images indicate that the CaSO4 crystals deposited in order on the non-biofouled membrane, whereas on the biofouled membrane they were embedded in the biofilm. The denser and thicker fouling layer formed with biofilm was impermeable, resulting in a high Ca2 +  rejection. The complexation of Ca with polysaccharide in biofilm would eliminate the cake-enhanced osmotic pressure effect leading to a slow flux decline. To sum up, the independent measurements corroborate the ultrasonic measurements.

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