Modeling of Euclidean braided fiber architectures to optimize composite properties

Three-dimensional braided fiber reinforcements are a very effective toughening mechanism for composite materials. The integral yarn path inherent to this fiber architecture allows for effective multidirectional dispersion of strain energy and negates delamination problems. In this paper a geometric model of Euclidean braid fiber architectures is presented. This information is used to determine the degree of geometric isotropy in the braids. This information, when combined with candidate material properties, can be used to quickly generate an estimate of the available load-carrying capacity of Euclidean braids at any arbitrary angle

Delayed Graduation and Overeducation: A Test of the Human Capital Model Versus the Screening Hypothesis

The academic circles are devoting a growing interest to delayed graduation and overeducation, but none has analyzed the joint consequences of these two phenomena. Thus, this paper studies the link between graduation not within the minimum period and overeducation, and the effects of these variables on wages, using the ISFOL-Plus data. According to the human capital model, delayed graduation increases a student\u2019 human capital and should, therefore, reduce her probability of being overeducated, while increasing her wage. According to the screening hypothesis, instead, delayed graduation signals low skills and therefore increases the chances of being overeducated, while bearing a wage penalty. The evidence lines towards predictions based on the screening hypothesis. First, delayed graduation increases the chances of overeducation. In addition, the direct wage penalty associated to delayed graduation equals 7% of the median wage. However, being a determinant of overeducation, it also indirectly contributes to the penalty of 19.8% of the median wage associated to overeducation. These effects are sizeable, considering the very low returns to higher education in Italy reported in previous studies