Search results for " SCIENZA"
showing 10 items of 1301 documents
Ultrasonic Guided Waves-Based Monitoring of Rail Head: Laboratory and Field Tests in Advances in Civil Engineering
2010
Recent train accidents have reaffirmed the need for developing a rail defect detection system more effective than that currently used. One of the most promising techniques in rail inspection is the use of ultrasonic guided waves and noncontact probes. A rail inspection prototype based on these concepts and devoted to the automatic damage detection of defects in rail head is the focus of this paper. The prototype includes an algorithm based on wavelet transform and outlier analysis. The discrete wavelet transform is utilized to denoise ultrasonic signals and to generate a set of relevant damage sensitive data. These data are combined into a damage index vector fed to an unsupervised learning…
Improved Global-Local method for ultrasonic guided wave scattering predictions in composite waveguides and defects
2022
As structures increase in complexity, both in the use of advanced materials and high-performing designs such as composite assemblies, their health assessment becomes increasingly challenging. Ultrasonic guided waves (UGWs) have shown to be very promising in the inspection of large (i.e. aerospace components) attenuating (i.e. composite materials) structures and have been successfully employed for damage detection in a variety of fields. The intrinsic complex nature of UGWs, due to their dispersive behavior, combined with the structural complexity of the applications, though, requires improved inspection solutions of higher resolution and accuracy to ensure efficient and safe operations. The…
Adhesive debonding detection of FRP reinforcement by the ultrasonic non-destructive technique
2015
Fiber reinforced polymer (FRP) composite systems are extensively used for repairing and reinforc- ing structurally inefficient concrete structures. The performance of an FRP rehabilitation system is highly influenced by its integrity. In particular, the presence of defects, e.g. voids, inclusions, debonds, improper cure and delaminations, caused by an inaccurately manufacture and installation, may affect the capability of the rehabilitated structure. For this reason, non-destructive (ND) meth- ods could be used to assess the quality of the reinforcement [1,2]. In this work an ultrasonic ND technique for detecting delamination defects in FRP reinforcement is presented. The technique couples …
Un nuovo codice epistemologico
2017
Nelle Lezioni di pedagogia fondamentale, curate dall'Autore, questo testo costituisce il capitolo iniziale della Seconda unità formativa, dal titolo Il costituirsi della pedagogia come scienza distinta. Epistemologia della pedagogia.Scrive l'Autore in avvio del capitolo: "È questa ricerca del vero che ci ha fatto parlare non più di pedagogia spontanea, ma di pedagogia razionale; e a partire da questa Lezione, si tratta proprio di assumere questo compito, di iniziare a elaborare una riflessione sull’educazione segnata dalla ragione. Ora, un primo dato subito s’impone con evidenza: non è praticabile sensatamente nessuna concreta ricerca razionale, nessuna definita elaborazione di un sapere, s…
Fractional-order theory of thermoelasticicty. I: Generalization of the Fourier equation
2018
The paper deals with the generalization of Fourier-type relations in the context of fractional-order calculus. The instantaneous temperature-flux equation of the Fourier-type diffusion is generalized, introducing a self-similar, fractal-type mass clustering at the micro scale. In this setting, the resulting conduction equation at the macro scale yields a Caputo's fractional derivative with order [0,1] of temperature gradient that generalizes the Fourier conduction equation. The order of the fractional-derivative has been related to the fractal assembly of the microstructure and some preliminary observations about the thermodynamical restrictions of the coefficients and the state functions r…
Some insights on the link between terrorism, organised crime and ‘new wars’
2014
Purpose - The purpose of this chapter is to investigate on the relationship between terrorism, criminal organisations, and the so-called 'new wars'. Methodology/approach - Review of the existing literature on the 'new wars' and on the terrorism-crime nexus; estimate of the financial revenues gained by terrorist groups engaged in illicit activities. Findings -Terrorist and criminal groups can develop several forms of collaboration. Whether terrorists convert to criminal activities or not depends on a variety of factors, both internal and external. In some cases these links are occasional and opportunistic, associated with the possibility of exploiting the availability of specialised competen…