Modelling of the viscoelastic behaviour of amorphous thermoplastic/glass beads composites based on the evaluation of the complex Poisson's ratio of the polymer matrix

A series of polystyrene/glass beads composites were studied by using dynamic mechanical spectrometry. From experimental data obtained under isothermal conditions, a simulation method of viscoelastic behaviour of amorphous thermoplastics reinforced by glass beads was devised. Such a theoretical approach confirmed the requirement of considering the Poisson's ratio as a complex component over all the temperature range. This could be related to the difference of many powers of ten between the moduli of the two phases. Thus, we suggest in this paper a method to evaluate the complex Poisson's ratio of the matrix. From these results, the influence of filler content on the magnitude of the mechanical relaxation related to the glass transition is taken into account.     

Modeling of the relationship between morphology and viscoelastic behavior of unidirectional fiber-reinforced polymers

A new approach is proposed to predict the relationship between geometric arrangement of fibers within the polymer matrix and viscoelastic behavior displayed by unidirectional fiber-reinforced polymers. Based on a quantitative morphology analysis of epoxy/glass fibers composites, a four-phase model taking into account the fiber spatial distribution is developed to rigorously express the reinforcement effect of the polymer matrix over a wide range of fibers and temperatures. Comparisons with other modelings and experiment illustrate the validity of the proposed approach. In addition, changes in the viscoelastic behavior of the epoxy matrix in composite materials resulting from a decrease in the crosslinking degree of such a kind of polymer are, subsequently, assessed through such an approach.     

Segmentation of brain MRI using active contour model

Alzheimer disease is a neurodegenerative disorder that impairs memory, cognitive function, and gradually leads to dementia, physical deterioration, loss of independence, and death of the affected individual. In this context, segmentation of medical images is a very important technique in the field of image analysis and Computer‐Assisted Diagnosis. In this article, we introduce a new automatic method of brain images’ segmentation based on the Active Contour (AC) model to extract the Hippocampus and the Corpus Callosum (CC). Our contribution is to combine the geometric method with the statistical method of the AC. We used the Caselle Level Set and added a learning phase to build an average shape and to make the initialization task automatic. For the step of contour evolution, we used the principle of Level set and we added to it the a priori knowledge. Experimental results are very promising. © 2017 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 27, 3–11, 2017     

Elderly fall detection based on multi-stream deep convolutional networks

Multimedia Tools and Applications - Fall is the biggest threat to seniors, with significant emotional, physical and financial implications. It is the major cause of serious injuries, disabilities,...     

Local generic representation for patch uLBP-based face recognition with single training sample per subject

Multimedia Tools and Applications - In this paper, we propose a novel paradigm of Patch uniform Local Binary Patterns (PuLBP) based Local Generic Representation (LGR) for face recognition. Indeed,...     

Study of primary resistance to antitubercular agents in the Sousse region, 1981-1990

Spatone Iron-Plus is a naturally occurring mineral water from Trefriw Wells Spa in Gwynedd, Wales, UK which contains approximately 0.3 mg of iron per ml as ferrous sulphate. The water has been taken as a tonic since Victorian times. Iron absorption from Spatone Iron-Plus was measured in a whole body counter after labelling the water with [59Fe] ferrous sulphate. Absorption studies were carried out in 13 subjects. Mean absorption for 10 ml of Spatone Iron-Plus taken on an empty stomach was 23 percent. Absorption was related to body iron stores as assessed by serum ferritin. In subjects with a serum ferritin concentration of <10 mu g/I, absorption was approximately 40 percent but was <10 percent in subjects with ferritin concentrations of approximately 200 mu g/I. This study indicates that Spatone Iron-Plus provides iron in a highly bio-available form.     

Influence of silane flow on MOVPE grown GaN on sapphire substrate by an in situ SiN treatment

In this paper, the influence of silane flow on metalorganic vapour phase epitaxy (MOVPE) grown GaN on sapphire substrate by an in situ SiN treatment has been investigated. A flow of 10 sccm with treatment duration of 120 s appears to be the optimal value and improves the crystal quality. The dislocation density, determined by atomic force microscopic (AFM), is as low as 5×10⁸ cm⁻². A reduction of I₂ full width at half maximum (FWHM) to 4 meV and an increase of both BE/YL and BE/DAP intensity ratio are also obtained.