Energy harvesting from earthquake for vibration-powered wireless sensors

Wireless sensor networks can facilitate the acquisition of useful data for the assessment and retrofitting of existing structures and infrastructures. In this perspective, recent studies have presented numerical and experimental results about self-powered wireless nodes for structural monitoring applications in the event of earthquake, wherein the energy is scavenged from seismic accelerations. A general computational approach for the analysis and design of energy harvesters under seismic loading, however, has not yet been presented. Therefore, this paper proposes a rational method that relies on the random vibrations theory for the electromechanical analysis of piezoelectric energy harvesters under seismic ground motion. In doing so, the ground acceleration is simulated by means of the Clough-Penzien filter. The considered piezoelectric harvester is a cantilever bimorph modeled as Euler-Bernoulli beam with concentrated mass at the free-end, and its global behavior is approximated by the dynamic response of the fundamental vibration mode only (which is tuned with the dominant frequency of the site soil). Once the Lyapunov equation of the coupled electromechanical problem has been formulated, mean and standard deviation of the generated electric energy are calculated. Numerical results for a cantilever bimorph which piezoelectric layers made of electrospun PVDF nanofibers are discussed in order to understand issues and perspectives about the use of wireless sensor nodes powered by earthquakes. A smart monitoring strategy for the experimental assessment of structures in areas struck by seismic events is finally illustrated

Assessing the impact of banks’ high-tech investments on efficiency. What is the actual relationship direction?

This paper analyses whether there is any relationship between the efficiency level achieved by Euro Area banking groups and their attitude toward high-tech investments proxied by high-tech patents. We measure banking efficiency via Data Envelopment Analysis (DEA). The period considered is the decade between 2012 and 2021. The results obtained show that there is a generally negative relationship between the two topics under investigation. The evidence obtained justifies the importance of an appropriate level of attention by regulators since increasing levels of technological innovation pursued through significant growth in intangible assets, could negatively affect the overall financial system efficiency

The Relationship Between the Civic Engagement of Parents and Children : a Cross-National Analysis of 18 European Countries

Although previous research has suggested the existence of a positive association between the political activities of parents and children, little is known about other forms of civic engagement. In particular, the literature lacks an international comparative study on the intergenerational transmission of civic involvement. Using Bayesian multilevel models on data from the European Union Statistics on Income and Living Conditions (EU-SILC) 2006 special module on social participation, this article tests hypotheses on the patterns of civic engagement of parents and children in 18 European countries with different political legacies. Our results show a positive association between the participation in associational activities of parents and children in all the considered countries, above and beyond individual and contextual characteristics. In particular, we do not find an evident East\u2013West gap in the socialization process, suggesting that the Communist past of Eastern and Central European countries has little influence on what can be considered a basic mechanism of civic learning