All-season monitoring of concrete repair in an urban tunnel in Brussels using embedded ultrasonic transducers with emphasis on robustness to environmental variations

2021 ◽  
Author(s):  
Cédric Dumoulin ◽  
Arnaud Deraemaeker
Keyword(s):  
Ultrasonic Transducers ◽  
Concrete Repair ◽  
Environmental Variations

The heritability of mental traits in humans: A proposal for a more coherent discussion

2003 ◽  
Vol 62 (1) ◽  
pp. 5-10 ◽  
Author(s):  
Manfred Velden
Keyword(s):  
Heritability Estimate ◽  
Environmental Variations ◽  
Heritability Estimates

It is proposed to simplify the debate about the heritability of mental traits in humans by concentrating on two crucial issues: Population specificity of heritability estimates and the relation of these estimates to the malleability of the trait to which they refer. It is demonstrated that due to vast differences between the environmental variations of populations there would have to be a heritability estimate for every imaginable population, and that a heritability estimate allows no predictions whatsoever about the malleability of the trait in question. It is therefore concluded that this field of research should be abandoned.

Modelling of functionally graded piezoelectric ultrasonic transducers

2007 ◽  
Author(s):  
Wilfredo M. Rubio ◽  
Flavio Buiochi ◽  
Julio C. Adamowski ◽  
Emilio C. N. Silva
Keyword(s):  
Functionally Graded ◽  
Ultrasonic Transducers ◽  
Functionally Graded Piezoelectric

Ultrasonic transducers using PVDF

1991 ◽  
Vol 115 (1) ◽  
pp. 267-278 ◽  
Author(s):  
S. Hurmila ◽  
H. Stubb ◽  
J. Pitkanen ◽  
K. Lahdenpera ◽  
A. Penttinen ◽  
...  
Keyword(s):  
Ultrasonic Transducers

Effect of mechanical restraint on the rate of corrosion in concrete

1998 ◽  
Vol 25 (1) ◽  
pp. 81-86 ◽  
Author(s):  
N Hearn ◽  
J Aiello
Keyword(s):  
Mix Design ◽  
Concrete Repair ◽  
Accelerated Corrosion ◽  
One Dimensional ◽  
Mechanical Restraint ◽  
Corrosion Rates ◽  
Accelerated Corrosion Tests ◽  
The Matrix ◽  
The Relationship

Experimental work on prismatic concrete specimens was conducted to determine the relationship between mechanical restraint and the rate of corrosion. The current together with the changes in strain of the confining frame were monitored during the accelerated corrosion tests. The effect of mix design and cracking on the corrosion rates was also investigated. The results show that one-dimensional mechanical restraint retards the corrosion process, as indicated by the reduction in the steel loss. Improved quality of the matrix, with and without cracking, reduces the rate of steel loss. In the inferior quality concrete, the effect of cracking on the corrosion rate is minimal.Key words: corrosion, concrete, repair.

scholarly journals Encapsulation of Capacitive Micromachined Ultrasonic Transducers (CMUTs) for the Acoustic Communication between Medical Implants

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 421
Author(s):  
Jorge Oevermann ◽  
Peter Weber ◽  
Steffen H. Tretbar
Keyword(s):  
Data Security ◽  
Ultrasonic Transducers ◽  
Surrounding Tissue ◽  
Center Frequency ◽  
Medical Implants ◽  
Research Groups ◽  
Capacitive Micromachined Ultrasonic Transducers ◽  
Polyether Ether Ketone ◽  
High Bandwidth ◽  
Ether Ketone

The aim of this work was to extend conventional medical implants by the possibility of communication between them. For reasons of data security and transmitting distances, this communication should be realized using ultrasound, which is generated and detected by capacitive micromachined ultrasonic transducers (CMUTs). These offer the advantage of an inherent high bandwidth and a high integration capability. To protect the surrounding tissue, it has to be encapsulated. In contrast to previous results of other research groups dealing with the encapsulation of CMUTs, the goal here is to integrate the CMUT into the housing of a medical implant. In this work, CMUTs were designed and fabricated for a center frequency of 2 MHz in water and experimentally tested on their characteristics for operation behind layers of Polyether ether ketone (PEEK) and titanium, two typical materials for the housings of medical implants. It could be shown that with silicone as a coupling layer it is possible to operate a CMUT behind the housing of an implant. Although it changes the characteristics of the CMUT, the setup is found to be well suited for communication between two transducers over a distance of at least 8 cm.

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