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

The Best Is Yet to Come? Attitudes towards gender roles among adolescents in 36 countries

In the present article, we look at attitudes toward gender roles among young women and men in 36 countries with different levels of societal gender inequality. By applying multilevel models to data from the International Civic and Citizenship Education Study 2009, the study contributes to our understanding of gender inequality by showing that (a) both young women and young men (in 8th grade; Mage = 14.39 years) display more gender-egalitarian attitudes in countries with higher levels of societal gender equality; (b) young women in all countries have more egalitarian attitudes toward gender roles than young men do, but (c) the gender gap in attitudes is more evident in more egalitarian contexts; and (d) a higher level of maternal education is associated with more gender-egalitarian attitudes among young women. In contrast, no statistically significant association emerges between maternal employment and young men\u2019s attitudes. Overall, the findings suggest that adolescents in different contexts are influenced by the dominant societal discourse on gender inequality, which they interiorize and display through their own attitudes toward gender roles. However, the findings also indicate that young women are more responsive to external cues than young men are. This result, coupled with the fact that young men in egalitarian contexts have not adopted gender-egalitarian attitudes to the same extent as young women, is concerning because it suggests a slowdown in the achievement of societal gender equality that is still far from being reache

Knowledge, attitudes, and behavior concerning dental trauma among parents of children attending primary school

BACKGROUND: Traumatic dental injuries occur frequently in children and adolescents. The purpose of the present study is to examine the levels of knowledge and behaviors regarding dental trauma among parents of children attending primary schools in the Apulia region of Italy. METHODS: The study was carried out using an anonymous questionnaire with closed answers distributed to 2,775 parents who were enrolled based on the entire regional school population. Analyses were conducted using the PROC CORRESP (procedure to perform multiple correspondence analysis) and PROC FASTCLUS (procedure to perform cluster analysis). Statistical significance was set at p-value <0.05. RESULTS: A total 15.5% of the sample reported that their children had experienced dental trauma. Overall, 53.8% of respondents stated that they knew what to do in cases of dental injury. Regarding the time limit within which it is possible to usefully intervene for dental trauma, 56.8% of respondents indicated "within 30 minutes". Of the total sample, 56.5% knew how to preserve a displaced tooth. A total 62.9% of parents felt it was appropriate for their children to use dental guards during sports activities. The multivariate analysis showed that wrong knowledge are distributed among all kinds of subject. Parents with previous experience of dental trauma referred right behaviours, instead weak knowledge and wrong behaviours are associated with parents that easily worried for dental events. CONCLUSIONS: This study showed that most parents reported no experience of dental trauma in their children, and half of them did not know what to do in case of traumatic dental injury and they would intervene within 30 minutes, suggesting that dental trauma may trigger panic. However, they did not have the information needed to best assist the affected child. Motivating parents to assume a preventive approach towards dental trauma may produce positive changes that would result an increase of long-term health benefits among both parents and children