Search results for "Ultrasonic sensor"
showing 10 items of 139 documents
Intravascular ultrasound imaging of arterial wall architecture.
1992
Intravascular ultrasound (IVUS) is a promising new technique for assessing vascular morphology and structure. Controversy exists whether the three-layer appearance of the arterial wall correctly reflects the histologic structures of the intima, media, and adventitia. We performed an experimental study to clarify the three-layer appearance. The vessel wall architecture was analyzed by IVUS on eight different kinds of plastic cylinders, 24 normal blood vessels from pigs, and 59 human arterial segments. A distinct three-layer appearance was observed on all the plastic cylinders when the ultrasound beam was perpendicular to the wall. A three-layer appearance was also seen in the arterial wall, …
Acoustic methods for measuring the porosities of porous materials incorporating dead-end pores
2013
International audience; The acoustic properties of porous materials containing dead-end (DE) pores have been proposed by Dupont et al. [J. Appl. Phys. 110, 094903 (2011)]. In the theoretical description, two physical parameters were defined (the dead-end porosity and the average length of the dead-end pores). With the knowledge of the open porosity (measured with non-acoustic methods), and the measurement of kinematic porosity (also called the Biot porosity in this article), it is possible to deduce the dead-end porosity. Two acoustic methods for measuring the Biot porosity for a wide range of porosities are proposed. These methods are based on acoustic transmission and on the low and high …
Model-assisted ultrasonic calibration using intentionally embedded defects for in-process weld inspection
2021
Abstract Automated in-process Non-Destructive Testing (NDT) systems are rapidly gaining traction within the manufacturing industry as they reduce manufacturing time and costs. When considering calibration and verification of such systems, creating defects of known geometry and nature during the deposition of a weld can: (I) help examine the capability of the automated system to detect and characterise defects, (II) be used to form a database of signals associated with different defect types to train intelligent defect classification algorithms, and (III) act as a basis for in-process gain calibration during weld inspection at high temperatures, where the ultrasound beam can be skewed as a r…
Some tests of 3D ultrasonic traveltime tomography on the Eleonora d'Aragona statue (F. Laurana, 1468)
2013
Abstract The use of a non-destructive technique in situ can be a valuable diagnostic tool to support verification of restoration, as well as a monitoring technique in works of art or historical monuments. We present a high resolution 3D ultrasonic tomography to one of the most important statues of the Regional Gallery of Palazzo Abatellis of Palermo, the bust of Eleonora d'Aragona by F. Laurana (1430–1502). This technique allowed to study the structural continuity of the material of the marble. Some tests have been carried out to optimize inversion parameters, such as voxel size and to choose between straight and curved rays. We propose to calculate a minimum lateral resolution using the sa…
Acoustic Topological Circuitry in Square and Rectangular Phononic Crystals
2021
International audience; We systematically engineer a series of square and rectangular phononic crystals to create experimental realizations of complex topological phononic circuits. The exotic topological transport observed is wholly reliant upon the underlying structure which must belong to either a square or rectangular lattice system and not to any hexagonal-based structure. The phononic system chosen consists of a periodic array of square steel bars which partitions acoustic waves in water over a broadband range of frequencies (∼0.5MHz). An ultrasonic transducer launches an acoustic pulse which propagates along a domain wall, before encountering a nodal point, from which the acoustic si…
Ultrasound assisted method to increase soluble chemical oxygen demand (SCOD) of sewage sludge for digestion
2004
The aim of this study was to clarify the possibilities to increase the amount of soluble chemical oxygen demand (SCOD) and methane production of sludge using ultrasound technologies with and without oxidising agents. The study was done using multivariate data analyses. The most important factors affected were discovered. Ultrasonically assisted disintegration increased clearly the amount of SCOD of sludge. Also more methane was produced from treated sludge in anaerobic batch assays compared to the sludge with no ultrasonic treatment. Multivariate data analysis showed that ultrasonic power, dry solid content of sludge (DS), sludge temperature and ultrasonic treatment time have the most signi…
Ultrasound accelerated esterification of bile acids
2004
In this study power ultrasound accelerated esterification reactions of some model substances and bile acids were done. In the model reactions the best result was 19-fold increase in the reaction rate when using ultrasound and the temperature was allowed to rise during the irradiation. In the case of bile acid methyl esters a clear increase in the reaction rates was also observed by ultrasonic irradiations.
Simulation of laser-generated ultrasonic wave propagation in solid media and air with application to NDE
2009
Ultrasonic methods are well known as powerful and reliable tool for defect detection. In the previous decades focus and interest have been directed to non-contact sensors and methods, showing many advantages over contact techniques where inspection depends on contact conditions (pressure, coupling medium, contact area). The non-contact hybrid ultrasonic method described here is of interest for many applications, requiring periodic inspection in service or after manufacturing. Despite the potential impact of laser-generated ultrasound in many areas of industry, robust tools for studying the phenomenon are lacking and thus limit the design and optimization of non-destructive testing and evalu…
Adapting robot paths for automated NDT of complex structures using ultrasonic alignment
2019
Automated inspection systems using industrial robots have been available for several years. The IntACom robot inspection system was developed at TWI Wales and utilizes phased array ultrasonic probes to inspect complex geometries, in particular aerospace composite components. To increase inspection speed and accuracy, off-line path planning is employed to define a series of robotic movements following the surface of a component. To minimize influences of refraction at the component interface and effects of anisotropy, the ultrasonic probe must be kept perpendicular to the surface throughout the inspection. Deviations between the actual component and computer model used for path-planning resu…
Determination of the adiabatic compressibility of bovine serum albumen in concentrated solution by a new ultrasonic method
2000
Abstract New data are presented for the adiabatic compressibility of bovine serum albumen (BSA) over the temperature range 2–85°C and at pH 5, 6, 7 and 8. The relative impact of intrinsic and hydration contributions to the observed compressibility for BSA is estimated and shown to agree very well with general values for globular protein and with previous results for BSA. The compressibility manifests a maximum value in the regions where BSA is most stable, exhibiting a parabolic dependence on temperature with lowest values where it is least stable. These data are obtained with a novel technique that employs a commercial, low cost and automated pulse echo apparatus for the measurement of the…