Biomedical subjects

P Calmon

Publications and source records attributed to P Calmon.

4 recordsLinked to original sources

PubMed2006

CIVA: an expertise platform for simulation and processing NDT data.

Ultrasonic modeling and simulation are more and more widely used by the different actors of industrial NDT. The applications are numerous and show a great variety: help for diagnosis, data reconstruction, performance demonstration, probe design and inspection parameters settling, virtual testing etc. The CEA (the French Atomic Energy Commission) is strongly involved in this evolution with the development of the CIVA expertise platform which gathers in the same software advanced processing and modeling tools. In the aim of fulfilling requirements of an intensive use the choice has been made to mainly adopt semi-analytical approximated methods. The wave propagation modeling is based on an integral formulation of the radiated field and applies the so-called pencil method. The modeling of beam-defect interaction and echoes formation mechanisms apply approximated theories such as Kirchhoff approximation or GTD. Over the years and with successive versions of the software, this approach is enriched by adaptations and improvements of the existing models or by new models, in order to extend the field of applicability of the simulation.

Journal Article↗

PubMed2006

Simulation and data reconstruction for NDT phased array techniques.

Phased array techniques are now widely employed for industrial NDT applications in various contexts. Indeed, phased array present a great adaptability to the inspection configuration and the application of suitable delay laws allows to optimize the detection and characterization performances by taking into account the component geometry, the material characteristics, and the aim of the inspection. In addition, the amount of potential information issued from the inspection is in general greatly enhanced. It is the case when the employed method involve sequences of shots (sectorial scanning, multiple depth focusing etc) or when signals received on the different channels are stored. At last, application of electronic commutation make possible higher acquisition rates. Accompanying these advantages, it is clear that an optimal use of such techniques require the application of simulation-based algorithms at the different stages of the inspection process: When designing the probe by optimizing number and characteristics of element; When conceiving the inspection method by selecting suitable sequences of shots, computing optimized delay laws and evaluating the performances of the control in terms of zone coverage or flaw detection capabilities; When analysing the results by applying simulation-helped visualization and data reconstruction algorithms. For many years the CEA (French Atomic Energy Commission) has been being greatly involved in the development of such phased arrays simulation-based tools. In this paper, we will present recent advances of this activity and show different examples of application carried out on complex situations.

Computer Simulation↗

PubMed2005

Radionuclide migration in forest ecosystems--results of a model validation study.

The primary objective of the IAEA's BIOMASS Forest Working Group (FWG) was to bring together experimental radioecologists and modellers to facilitate the exchange of information which could be used to improve our ability to understand and forecast radionuclide transfers within forests. This paper describes a blind model validation exercise which was conducted by the FWG to test nine models which members of the group had developed in response to the need to predict the fate of radiocaesium in forests in Europe after the Chernobyl accident. The outcomes and conclusions of this exercise are summarised. It was concluded that, as a group, the models are capable of providing an envelope of predictions which can be expected to enclose experimental data for radiocaesium contamination in forests over the time scale tested. However, the models are subject to varying degrees of conceptual uncertainty which gives rise to a very high degree of divergence between individual model predictions, particularly when forecasting edible mushroom contamination. Furthermore, the forecasting capability of the models over future decades currently remains untested.

Ecosystem↗

PubMed2000

Modeling of propagation and echo formation in a multilayered structure

In the aim of simulating the ultrasonic inspection of multilayered structure, we propose a hybrid model, based on transfer matrices and ray tracing formalisms. This approach allows one to predict the response of structures containing defects of finite size such as delaminations or adhesion defect.

Journal Article↗