Search results for "T method"

BE contact analysis of delamination cracks actively repaired trhough piezoelectric active patches

2009

Analysis of piezoelectric active patches performances by boundary element techniques

2008

This paper presents the analysis of active piezoelectric patches for cracked structures by Boundary Element Method. A two dimensional boundary integral formulation based on the multidomain technique is used to model cracks and to assemble the multi-layered piezoelectric patches to the host damaged structures. The fracture mechanics behavior of the repaired structures is analyzed for both perfect and imperfect interface between patches and host beams. The imperfect interface, representing the adhesive between two different layers, is modeled by using a “Spring Model” that involves linear relationships between the interface tractions, in normal and tangential directions, and the respective di…

Hierarchical adaptive cross approximation GMRES technique for solution of acoustic problems using the boundary element method

2009

In this paper a new Rapid Acoustic Boundary Element Method (RABEM) is presented using a Hierarchical GMRES solver for 3D acoustic problems. The Adaptive Cross Approximation is used to generate both the system matrix and the right hand side vector. The ACA is also used to evaluate the potential and the particle velocity values at selected internal points. Two different GMRES solution strategies (without preconditioner and with a block diagonal preconditioner) are developed and tested for low and high frequency problems. Implementation of different boundary conditions (i.e. Dirichlet, Neumann and mixed Robin) is also described. The applications presented include the problem of noise acting on…

La mesure directe des forces de liaison entre les hydrates appliquée à la prise de plâtre

1998

Le phenomene de prise est un phenomene general, observable sur tous les liants mineraux, ciments siliceux, alumineux... et le plâtre. S'il existe des lois gouvernant la prise, elles doivent s'appliquer a tous ces liants. Aussi, il peut etre justifie de prendre tel ou tel liant pour modele si cela peut simplifier la premiere approche. Ici, l'objectif est de mesurer les forces entre les grains de silicate de calcium hydrate (phase C-S-H) qui est l'hydrate le plus caracteristique des ciments courants. Ces grains sont extremement petits et il a ete choisi de mettre au point les methodes travaillant sur le plâtre qui s'hydrate sous forme de gypse en formant des cristaux de 10 a 100 fois plus gro…

On the use of the electromechanical impedance technique for the assessment of dental implant stability: Modeling and experimentation

2014

We propose the electromechanical impedance technique to monitor the stability of dental implants. The technique consists of bonding one wafer-type piezoelectric transducers to the implant system. When subjected to an electric field, the transducer induces structural excitations which, in turn, affect the transducer’s electrical admittance. The hypothesis is that the health of the bone surrounding the implant affects the sensor’s admittance. A three-dimensional finite element model of a transducer bonded to the abutment of a dental implant placed in a host bone site was created to simulate the progress of the tissue healing that occurs after surgery. The healing was modeled by changing the …

A fast two-point method for gas adsorption measurements

2000

Project Method in Adult Education: Self-Experience Analysis

2015

<p><em>The </em><em>project methodhas swiftly gained ground in education and it has nowbecome integral to the education process offering new ways for modernizing the education environment.Implementing projects provides learning opportunities for all of the involved parties – students, teachers, school principals and parents. In this article the Author has analysed the characteristics of the project method and the differences between project-based adult learningand non-adult learning,and the impact ofglobalization on projects. Projects can be implemented not only in the scope of specific subjects or specific schools but also as cooperation projects among schools of di…

Magnetic resonance chondro-crassometry (MR CCM): a method for accurate determination of articular cartilage thickness?

1996

A method for the assessment of articular cartilage thickness based on MRI is presented and its accuracy and reproducibility tested. Six specimens of human patellae were imaged, using a fat-suppressed FLASH 3D sequence, and sectioned with a high-precision band saw. The regional distribution of articular cartilage thickness was determined from the MR images and from the anatomical sections (intervals of 0.5 mm). With image analysis 50-90% of the image points were found to lie within exactly the same thickness interval in corresponding patterns, and less than 17% deviated more than 0.5 mm. More than 85% of all pixels were reproducible with MRI after new positioning of the joint. No influence o…

A finite element-based machine learning approach for modeling the mechanical behavior of the breast tissues under compression in real-time

2017

[EN] This work presents a data-driven method to simulate, in real-time, the biomechanical behavior of the breast tissues in some image-guided interventions such as biopsies or radiotherapy dose delivery as well as to speed up multimodal registration algorithms. Ten real breasts were used for this work. Their deformation due to the displacement of two compression plates was simulated off-line using the finite element (FE) method. Three machine learning models were trained with the data from those simulations. Then, they were used to predict in real-time the deformation of the breast tissues during the compression. The models were a decision tree and two tree-based ensemble methods (extremely…

Coincidence of mandibular fractures with isolated posterior maxillary sinus fractures

2017

Background/aim There are no data available to show whether there is a relationship between mandibular fractures and isolated fractures of the posterior and/or lateral walls of the maxillary sinus. The aim of this study was to determine whether there is a coincidence between these fracture patterns. Methods Four hundred large volume cone beam computed tomography scans (CBCT) of patients with a fracture of the mandible between 2008 and 2013 were analyzed retrospectively. Patients with multiple midfacial fractures were excluded. The radiographic findings were correlated with epidemiological and clinical data of the patients such as gender, age, treatment methods, or complications. Results The …