Artificial neural networks (ANNs) and a group-contribution approach were used to develop an algorithm to predict activity coefficients for binary solutions. The Levenberg-Marquardt algorithm was used to train the ANN and to predict the parameters of the Margules equation. The ANN was trained using phase-equilibrium database from DECHEMA. The selected systems include alcohols, phenols, aldehydes, ketones, and ethers. The trim mean based on 20% data elimination was selected as the best representation of the Margules-equation parameters. The algorithm was validated with 121 VLE systems and results show that the ANN provides a relative improvement over the UNIFAC method.Des réseaux de neurones artificiels (RNA) et une méthode de contribution de groupe ontété utilisés pour créer un algorithme permettant de prédire les coefficients d'activité des solutions binaires. L'algorithme de Levenberg-Marquardt aété utilisé pour entraîner le RNA et pour prédire les paramètres de l'équation de Margules. Le RNA aété entraîné en utilisant la base de données du diagramme d'équilibre de DECHEMA. Les systèmes sélectionnés comprennent les alcools, les phénols, les acétaldéhydes, les cétones et leséthers. La moyenne basée sur l'élimination de 20% des données aété sélectionnée commeétant celle représentant le mieux les paramètres de l'équation de Margules. L'algorithme aété validé avec 121 systèmes d'ELV et les résultats indiquent que le RNA conduità une amélioration relative par rapport au modèle UNIFAC.
In this work, tensile and shear modulus, as well as Poisson's ratio of a woven orthotropic nanocomposite plate were determined from vibration data. Plates used in the experiment were 16 layers S2-glass/epoxy composite manufactured by vacuum assisted wet layup. The nanocomposite plate was obtained by adding 0%, 1%, 2%, 5% and 10% nanoclays in weight to the epoxy matrix. A Finite Element model of the composite plate combined with a gradient method was applied to obtain an approximate numerical solution to experimental data in order to estimate the mechanical properties. Two different modal procedures were employed: the Laser Anemometry and Hammer test. A modal analysis was made in both cases to determine structural mode shape and associated frequencies, modal and mechanical properties for different nanoclay composite plates, as well as assessing its sensitivity to Modal Analysis.
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