Search Results (3)

Computational models of turbofans that are oriented to assist the design and testing of innovative components are of fundamental importance in order to reduce their environmental impact. In this paper, we present an effective method for developing numerical turbofan models that allows reliable steady-state turbofan performance calculations. The main difference between the proposed method and those used in various commercial algorithms, such as GasTurb, GSP 12 and NPSS, is the use of neural networks as a multidimensional interpolation method for rotational component maps instead of classical $\beta$ parameter. An additional aspect of fundamental importance lies in the simplicity of implementing this method in Matlab and the high degree of customization of the turbofan components without performing any manipulation of variables for the purpose of reducing the dimensionality of the problem, which would normally lead to a high condition number of the Jacobian matrix associated with the nonlinear turbofan system (and, thus, to significant error). In the proposed methodology, the component behavior can be modeled by analytical relationships and through the use of neural networks trained from component bench test data or data obtained from CFD simulations. Generalization of rotational component maps by feedforward neural networks leads to an average interpolation error up to around $1\%$, for all variables. The resulting nonlinear system is solved by a combined genetic algorithm and least squares algorithm approach, instead of the standard Newton’s method. The turbofan numerical model turns out to be convergent, and results suggest that the trend in overall turbofan performance, as flight conditions change, is in agreement with the outputs of the GSP 12 software. Full article

Some human literature suggests a possible role of endocrine disruptors (EDs) exposure in thyroid cancer (TC) development. We investigated TC incidence in selected Italian National Priority Contaminated Sites (NPCS) with documented presence of EDs considered thyroid carcinogens. Adjusted Standardized Incidence Ratios (SIRs), with their 90% confidence intervals, were computed by gender, and age-specific groups (aged 15–39 years, and 40 years or over) for each NPCS in the period 2006 to 2013. In the age group of 15–39 years, a significant excess of TC risk was found in two NPCSs in males; non-significant excess risks were observed in four NPCSs in males, and in five in females. In the age group of 40 years and over, significant excess risks were found in six NPCSs in males and in seven NPCSs in females; non-significant excess risks were identified in two NPCSs in males and females. The findings of several excesses in incidence, mainly observed in adults aged 40 years or over, are suggestive of a possible adverse effect associated with residence in NPCSs, even if a role of other factors cannot be excluded, due to the adoption of an ecological study design. Future analytical studies are needed to clarify if EDs are a TC risk factor for individuals living in NPCSs. Full article

In this work, a novel high-order formulation for multilayered piezoelectric plates based on the combination of variable-order interior penalty discontinuous Galerkin methods and general layer-wise plate theories is presented, implemented and tested. The key feature of the formulation is the possibility to tune the order of the basis functions in both the in-plane approximation and the through-the-thickness expansion of the primary variables, namely displacements and electric potential. The results obtained from the application to the considered test cases show accuracy and robustness, thus confirming the developed technique as a supplementary computational tool for the analysis and design of smart laminated devices. Full article