Nondestructive evaluation of early age properties of concrete using a polymer based piezoelectric sensor (Conference Presentation)

2018 ◽  
Author(s):  
Ehsan Ghafari ◽  
Ying Yuan ◽  
Na Lu ◽  
Romika Roshan Kotian
Keyword(s):  
Nondestructive Evaluation ◽  
Piezoelectric Sensor ◽  
Early Age

Curing Strength Monitoring of Early-Age Concrete Based on Velocity of Guided Wave Using Embedded Plate-Type PZT Sensor Module

2013 ◽  
Vol 281 ◽  
pp. 645-648
Author(s):  
Ju Won Kim ◽  
Eun Seok Shin ◽  
Chang Gil Lee ◽  
Seung Hee Park ◽  
Seo Kinn Hong
Keyword(s):  
Compressive Strength ◽  
Wave Velocity ◽  
Steel Plate ◽  
Piezoelectric Sensor ◽  
Guided Wave ◽  
Early Age ◽  
Monitoring Method ◽  
Sensor Module ◽  
Early Age Concrete ◽  
Plate Type

In this study, a guided wave based nondestructive curing strength monitoring method is proposed to monitor the curing strength of the early-age concrete. This approach used the embedded steel plate-type PZT sensor module which was fabricated by bonding the two pieces of piezoelectric sensor to a steel plate. The steel plate provided the constant path for guided wave propagation and it protected the piezoelectric sensors from impacts and environmental variations. To measure the guided wave signals from the early-age concrete, fabricated sensor modules were landfilled at the same time with concrete placement.While the concrete was curing, guided wave signals were measured by pitch-catch method continuously at regular intervals. Wavelet transform process was performed to improve the quality of the signal by removing the signal’s noise of undesired frequencies. The TOF (Time of flight) of guidedwave was extract from de-noised signal using peak tracing algorithm to calculate the velocity of wave. The calculated wave velocity hysteresis according to the curing time was traced to analysis the pattern of variations of wave velocity. Finally, specific equations to estimate the strength of the concrete were derived using regression analysis based on the wave velocity and compressive strength from destructive compressive strength test.

A Community Based High Risk Register for Hearing Loss

1982 ◽  
Vol 47 (4) ◽  
pp. 373-375 ◽  
Author(s):  
James L. Fitch ◽  
Thomas F. Williams ◽  
Josephine E. Etienne
Keyword(s):  
Hearing Loss ◽  
System Identification ◽  
High Risk ◽  
Language Learning ◽  
Education Program ◽  
Communication System ◽  
Auditory Signal ◽  
Early Age ◽  
Community Based ◽  
Children With Hearing Loss

The critical need to identify children with hearing loss and provide treatment at the earliest possible age has become increasingly apparent in recent years (Northern & Downs, 1978). Reduction of the auditory signal during the critical language-learning period can severely limit the child's potential for developing a complete, effective communication system. Identification and treatment of children having handicapping conditions at an early age has gained impetus through the Handicapped Children's Early Education Program (HCEEP) projects funded by the Bureau of Education for the Handicapped (BEH).

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