A LINEAR TRANSFORMATION FOR THE RECONSTRUCTION OF THE RESPONSES BETWEEN SYSTEMS IN SIMILITUDE

The increasing attention towards the possibility of scaling structures and, therefore, systems in similitude in engineering field has led to plenty of methods which allow to reconstruct the response of a system, starting from that of a reference one. In fact, this approach would help to overcome the obstacles associated with full-scale testing, such as cost and setup. However, the associated predictions may not be fully reliable, due to some intrinsic limitations characterizing the traditional similitude methods (based on the definition of similitude conditions and scaling laws), such as: size effects, rate sensitivity phenomena, distorted similitudes. For this reason, a new method, called VOODOO (Versatile Offset Operator for the Discrete Observation of Objects), has been proposed; such a method is based on the definition of a transformation matrix which links the outputs between two sets of points belonging to a linear systems. The applications of VOODOO to plates and systems of plates demonstrate that an exact estimation of the frequency response is obtained when the degrees of freedom involved in the definition of the transformation are considered. Therefore, this work aims at investigating, by means of a sensitivity analysis, the method’s strengths and limitations when other degrees of freedom are considered, in order to identify the direction for further developments

INVESTIGATION ON THE ARTIFICIAL NEURAL NETWORKS PREDICTION CAPABILITIES APPLIED TO VIBRATING PLATES IN SIMILITUDE

The prediction capabilities of artificial neural networks in similitude field are investigated. They have been applied to plates in similitude with two objectives: prediction of natural frequencies and model identification. The results show that the method is able to give accurate predictions and that an experimental training set can be created if the models are well characterized

Support of Dynamic Measurements Through Similitude Formulations

Up to now, similitude methods have been used in order to overcome the typical drawbacks of experimental testing and numerical simulations by reconstructing the full-scale model behavior from that of the scaled model. The novelty of this work is the application of similitude theory not as a tool for predicting the prototype dynamic response, but for supporting, and eventually validating, experimental measurements polluted by noise. Two Aluminium Foam Sandwich (AFS) plates are analyzed with Digital Image Correlation (DIC) cameras. First, an algorithm for blind source separation problems is used to extract information about the excitation; then, SAMSARA (Similitude and Asymptotic Models for Structural-Acoustic Research Applications) similitude method is applied to both the force spectra and velocity responses of prototype and model. The reconstruction of force and velocity curves demonstrates that the similitude results are coherent with the quality of the experimental measurements: when the spatial pattern in resonance is recognizable, then the curves overlap. Instead, when the displacement field of just one model is not well identified, the reconstruction exhibits discrepancies. Therefore, similitude methods reveal to be an interesting tool for understanding if a set of measurements is reliable or not and their application should not be underestimated, especially in the light of the expanding range of approaches which can extract important information from noisy observations

Comparison of emotional approaches of medical doctors against COVID-19 pandemic: Eastern and Western Mediterranean countries

Background: Pandemics are states of disease that occur worldwide and sharply increase in populations. It causes life events which trigger anxiety, depression, anger, sleep deprivation, emotional distress and stress. World Health Organization (WHO) declared coronavirus disease 2019 (COVID-19) a pandemic on March 11, pointing to the over 118,000 cases in over 110 countries. Many healthcare workers became ill during the pandemic and some among them died. In this study, we aimed to evaluate and compare level of stress against COVID-19 pandemic among doctors from Turkey and Italy. Methods: This research is a cross-sectional study in which Perceived Stress Scale (PSS-10) and Secondary Traumatic Stress Scale (STSS) are administered online via social networks. All data collection tools were delivered to individuals between 1 and 15 June 2020 and filled in online with Google Forms application. In total, 618 individuals were included in this study and all of them were medical doctors. Results: Higher PS and STS levels were found related to female gender, being married, working in pandemic hospital and older ages. Stress levels were found statistically higher in Turkish doctors when compared to Italian doctors for both stress scales (Turkish/Italian PSS:20.18 ± 7.90/ 19.35 ± 6.71, STSS: 44.19 ± 13.29/ 38.83 ± 13.74). Conclusion: The number of doctors per 1000 of population is lower and per capita visits to a physician are higher in Turkey when compared to Italy. Besides pandemic, these heavier working conditions, increased weekly working hours can cause stress for Turkish doctors. Reporting information such this study is important and international collaborations are essential to plan future prevention strategies. We need to strengthen international ties and build more international collaborations rather than staying within our national silos. Additionally, interventions to promote mental well-being in health care professionals exposed to COVID-19 need to be immediately implemented

Disordered eating behaviors in youths with type 1 diabetes during COVID-19 lockdown: an exploratory study

Background: Recent research indicates that patients with type 1 diabetes (T1D) are at higher risk for disordered eating behaviors (DEBs) than their peers without diabetes. The present study aimed to explore the prevalence of DEBs in a sample of Italian children and adolescents with T1D and in matched-pair healthy controls during the COVID-19 lockdown. Methods: In a cross-sectional study, 138 children and adolescents with T1D (aged 8.01–19.11 years, 65 boys) attending a Southern Italian diabetic service and 276 age- and gender-matched healthy peers voluntarily completed an online survey about eating behaviors (ChEAT and EAT-26), anthropometric characteristics, and clinical characteristics. Results: 8.69% (N = 12) of participants with T1D and 13.4% (N = 37) of controls had ChEAT/EAT-26 scores indicating presence of DEBs, with no differences between patients—whether children (total ChEAT score F(1, 157) =.104, p =.748) or adolescents (total EAT-26 score F(1, 255) =.135, p =.731)—and healthy peers. zBMI values were lower than those measured in the latest diabetes visit (p <.0001), while HbA1c values remained unchanged (p =.110). In both groups, adolescents had lower Oral Control scores than children (T1D: F(1, 138) = 20.411, p <.0001, η2 =.132, controls: F(1, 276) = 18.271, p <.0001, η2 =.063); additionally, gender (female) and age were found to be significant predictors of several ChEAT/EAT-26 scores. Conclusions: This exploratory study suggested that children and adolescents with T1D did not experience more DEB symptoms during the COVID-19 lockdown compared to healthy controls. Results revealed DEBs as more of a female adolescent developmental issue rather than a result of the challenges of living with a chronic illness under quarantine measures. Possible effects of parental pressure on their children’s eating behaviors in the context of home confinement and of using a non-diabetes-specific measure to assess DEBs are discussed

Muon detection in electron-positron annihilation for muon collider studies

The investigation of the energy frontier in physics requires novel concept for future colliders. The idea of a muon collider is very appealing since it would aim to study particle collisions up to tens of TeV energy while offering a cleaner experimental environment with respect to hadronic colliders. One key element in the muon collider design is muon production with small emittance. Recently, the Low EMittance Muon Accelerator (LEMMA) collaboration has explored the close-to-threshold muon production by 45 GeV positron annihilating in a low Z material target. Muons are emerging with a natural small emittance. In this paper we describe the performance of a system of segmented absorbers with alternating active layers realized with fast Cherenkov detectors and a muon identification technique based on it. Passive layers were made of tungsten. Muons and electron beams data were collected in September 2018 at the H2 line in the North Area of the Conseil Européen pour la Recherche Nucléaire (CERN)

Il marchese Angelo Alberto Remedi e “Il desiderio e il pensiero di dedicarsi agli studi di archeologia”

Attraverso l’autobiografia di Alberto Angelo Remedi, si seguono le vicende formative e l’attività dello studioso che intrattenne relazione con importanti esponenti della cultura del suo tempo. Grazie all’attività di scavo condotta nei propri terreni a Luni, diede vita al primo museo lunense, favorendo lo sviluppo degli studi sulla città romana