Application of an electronic nose coupled with fuzzy-wavelet network for the detection of meat spoilage

Food product safety is one of the most promising areas for the application of electronic noses. During the last twenty years, these sensor-based systems have made odour analyses possible. Their application into the area of food is mainly focused on quality control, freshness evaluation, shelf-life analysis and authenticity assessment. In this paper, the performance of a portable electronic nose has been evaluated in monitoring the spoilage of beef fillets stored either aerobically or under modified atmosphere packaging, at different storage temperatures. A novel multi-output fuzzy wavelet neural network model has been developed, which incorporates a clustering pre-processing stage for the definition of fuzzy rules. The dual purpose of the proposed modelling approach is not only to classify beef samples in the relevant quality class (i.e. fresh, semi-fresh and spoiled), but also to predict their associated microbiological population. Comparison results against advanced machine learning schemes indicated that the proposed modelling scheme could be considered as a valuable detection methodology in food microbiology

Comparative evaluation of seven resistance interpretation algorithms and their derived genotypic inhibitory quotients for the prediction of 48 week virological response to darunavir-based salvage regimens

Background: the darunavir genotypic inhibitory quotient (gIQ) has been suggested as one of the predictors of virological response to darunavir-containing salvage regimens. Nevertheless, which resistance algorithm should be used to optimize the calculation of gIQ is still debated. The aim of our study was to compare seven different free-access resistance algorithms and their derived gIQs as predictors of 48 week virological response to darunavir-based salvage therapy in the clinical setting. Methods: patients placed on two nucleoside reverse transcriptase inhibitors\u200a+\u200a600/100 mg of darunavir/ritonavir twice daily \u200a\ub1\u200a enfuvirtide were prospectively evaluated. Virological response was assessed at 48 weeks. Darunavir resistance interpretation was performed according to seven different algorithms, of which two were weighted algorithms. Analysis of other factors potentially associated with virological response at 48 weeks was performed. Results: fifty-six treatment-experienced patients were included. Overall, 35 patients (62.5%) had a virological response at 48 weeks. Receiver operator characteristic curve analysis showed that De Meyer's weighted score (WS) and its derived gIQ (gIQ WS) were the most accurate parameters defining virological response, and related cut-offs showed the best sensitivity/specificity pattern. In univariate logistic regression analysis, baseline log viral load (P = 0.028), optimized background score 65 2 (P = 0.048), WS >5 (P = 0.001) and WS gIQ 65 600 (P\u200a<\u200a0.0001) were independently associated with virological response. In multivariate analysis, only baseline log viral load (P = 0.008) and WS gIQ 65 600 (P < 0.0001) remained in the model. Conclusions: in our study, although different resistance interpretation algorithms and derived gIQs were associated with virological response, gIQ WS was the most accurate predictive model for achieving a successful virological response

IJTC2011-61026 NORMAL AND TANGENTIAL CONTACT BETWEEN ANISOTROPIC MATERIALS

ABSTRACT A contact model using semi analytic methods, relying on elementary analytic solutions, has been developed. It is based on numeric techniques adapted to contact mechanics, with strong potential for inelastic, inhomogeneous or anisotropic problems. Recent developments aim to quantify displacements and stresses of an anisotropic material which is in contact with another anisotropic material. The influence of symmetry axes on the contact problem solution will be more specifically analyzed. INTRODUCTION Engineering problems are becoming more complicated when trying to reduce the gap between the model and the real application. It means that less restrictive assumptions should be made, or in other words more physics should be implemented in the model. Among the challenges to succeed in it, the material properties should be considered accurately. Supposing the material is isotropic is not enough. For most composite and mono-crystal materials their compositions or the elaboration and manufacturing processes imply that it exits one or two main directions or even a general anisotropy. The influence of the anisotropy orientations have to be taken into account to better predict the stress state in order to optimize the service life of industrial components. Several methods can be used for contact simulation of anisotropic materials. Semi analytical methods have proven their efficiency in contact mechanics and are developed here to account for anisotropy of materials. The main advantage is here the computing time compared to the Finite Element (FE) method that is however widely used for many contact problems. The contact model with its specificities when at least one of the bodies in contact behaves anisotropically will be first presented. Then, the influence of some parameters on the contact pressure distribution and strain and stress fields will be studied. The effect of the anisotropy orientation on the contact solution will be then investigated

WTC2005-63331 A MIXED MODE FATIGUE CRACK GROWTH MODEL APPLIED TO ROLLING CONTACT FATIGUE

ABSTRACT Extended finite element method simulation were conducted in order to evaluate mode I and II stress intensity factors (SIFs) for cracks under cyclic contact rolling and rolling-sliding conditions. The crack propagation mode and direction were investigated using criteria

WTC2005-63331 A MIXED MODE FATIGUE CRACK GROWTH MODEL APPLIED TO ROLLING CONTACT FATIGUE

ABSTRACT Extended finite element method simulation were conducted in order to evaluate mode I and II stress intensity factors (SIFs) for cracks under cyclic contact rolling and rolling-sliding conditions. The crack propagation mode and direction were investigated using criteria

Damage law identification of a quasi brittle ceramic from a b ending test using digital image correlation

The quasi brittle ceramics show a non linear mechanical behaviour resulting most of the time in a dissymetry between their tensile and compressive stress-strain laws. The characterization of their fracture strengths might be biased if elastic linear formulae are used to analyze classical tests like bending tests. Based on Digital Image Correlation (DIC), a methodology is proposed to characterize materials with dissymmetric behaviours. Applying specific DIC decomposition functions for bending, compressive and tensile tests, a stress-strain model and its damage law are identified for aluminium titanate, a damageable micro cracked ceramic. This identification method using DIC can obviously be applied to other quasi brittle materials