Advanced Vibro-Acoustic Techniques for Noise Control in Helicopters

Nowadays helicopters play a pivotal role in a wide variety of activities from important military missions to emergency medical transport, indeed it is a common experience that a helicopter may often be seen overhead. Originally, aircraft noise was not much of an issue because of the overarching requirement of improving vehicle performance in critical operational conditions. By the 1960s, noise and vibration control of helicopters has become more and more important and the next level technical challenge is to include new design parameters such as vibro-acoustic comfort and environmental impact in the design process of a modern rotorcraft. From one side, government regulations are imposed to contain noise pollution while on the other hand customers do not accept any longer a noisy product. On top of all this, the competitive pressure to bring products faster to market has made that NVH (Noise Vibration and Harshness) designers are looking for tools giving them an insight on where the noise is coming from. In this scenario, we want to present a modus operandi to tackle this issue by several advanced experimental methodologies, since the requirement of a quieter helicopter needs a systematic study of its NVH behavior. Experimental tests are carried and results are reported concerning two different helicopters: an EUROCOPTER EC-135 and an Agusta Westland W-109 helicopter. The proposed methodologies count several experimental NVH analyses and processing, which will be outline hereafter. It is interesting to note that although the presented methodologies concern particular helicopters, they have a general meaning, since they can be applied in a large variety of fields, as in aircraft fuselage, car or track interiors , etc. This work has to be intended as an analytical review of the authors’ research

Prototipazione FPGA di sottosistemi integrati per power management basati su ISA RISC-V

Fino a 15 anni fa, era possibile aumentare il numero di transistor su un singolo chip e contemporaneamente la sua frequenza di clock mantenendo la densità di potenza costante. Tuttavia dal 2004 non è più possibile mantenere invariata la potenza dissipata per unità d’area a causa di limitazioni fisiche. Al fine di aumentare le performance dei processori e di impedire una diminuzione delle frequenze di clock, i processori moderni integrano on-die dei Power Controller Subsystems (PCS) come risorsa hardware dedicata che implementa complesse strategie di gestione di temperatura e potenza. In questo progetto di tesi viene progettata l'architettura dell'interfaccia di comunicazione di ControlPULP, un PCS basato su ISA RISC-V, per la connessione verso un processore HPC. Tale interfaccia di comunicaione integra il supporto hardware per lo scambio di messaggi secondo la specifica SCMI. L'interfaccia sviluppata viene successivamente validata attraverso simulazione ed emulazione su supporto hardware FPGA. Tale supporto hardware viene inoltre utilizzato per la caratterizzazione dell'utilizzo di risorse dell'architettura progettata. Oltre allo sviluppo dell'interfaccia hardware viene sviluppato e caratterizzato un firmware per la decodifica dei messaggi SCMI conforme ai requisiti di esecuzione su un sistema real-time

Facial masks in children: the position statement of the Italian pediatric society

Facial masks may be one of the most cost-effective strategies to prevent the diffusion of COVID 19 infection. Nevertheless, fake news are spreading, alerting parents on dangerous side effects in children, such as hypercapnia, hypoxia, gut dysbiosis and immune system weakness. Aim of the Italian Pediatric Society statement is to face misconception towards the use of face masks and to spread scientific trustable information

Primary squamous cell carcinoma of the liver: an unexpected pathological finding

Abstract Background Primary squamous cell carcinoma of the liver is a very rare cancer requiring a complete diagnostic investigation, as it presents some differences from other primary hepatic malignancies. We describe the case of an elderly patient with primitive squamous cell carcinoma of the liver treated by percutaneous microwave ablation and transarterial chemoembolization. Case presentation Although the pathogenesis remains uncertain, a possible transformation of the biliary epithelium caused by chronic inflammation or metaplasia and subsequent malignant transformation of preexisting benign hepatic cysts has been suggested. A critical review of the existing literature was performed by focusing on the pathogenesis, clinical presentation, and the suggested therapeutic strategies. Conclusion A multidisciplinary approach is needed to face rare hepatic malignancies where there are no clear guidelines

Ranking the in vivo toxicity of nanomaterials in Drosophila melanogaster

In this work, we propose a quantitative assessment of nanoparticles toxicity in vivo. We show a quantitative ranking of several types of nanoparticles (AuNPs, AgNPs, cadmium-based QDs, cadmium-free QDs, and iron oxide NPs, with different coating and/or surface chemistries), providing a categorization of their toxicity outcomes. This strategy may offer an innovative high-throughput screening tool of nanomaterials, of potential and broad interest to the nanoscience community

Isokinetic Dynamometry and 1RM Tests Produce Conflicting Results for Assessing Alterations in Muscle Strength

The purpose of this study was to compare strength gains in the lower limbs, assessed by one maximum repetition (1RM) and isokinetic peak torque (PT), in young men undergoing a resistance training (RT) program. Twenty-seven young men performed resistance training twice a week for 11 weeks. Training involved two exercises for the lower body, two for the upper body and one for the midsection performed with three sets of 8-12 repetitions to momentary muscle failure. Before and after the training period, participants performed the 1RM test in the 45° leg press and knee extension PT in isokinetic dynamometry. The Pearson correlation coefficient was used to assess the relationship between the changes in 1RM and PT, and the Bland-Altman test was performed to check for agreement between the strength changes of both tests. There were significant changes in 1RM and PT of 23.98% and 15.96%, respectively (p \u3c 0.05). The changes in leg press 1RM were significantly higher than the ones in PT. The Bland-Altman analysis revealed that the tests were not equivalent. In conclusion, professionals and researchers involved in strength assessment should be aware that the results obtained by PT and 1RM are not equivalent when evaluating individual responsiveness and/or the efficacy of an intervention on muscle strength, as the results obtained show large variations and can be even conflicting

SiO2 nanoparticles biocompatibility and their potential for gene delivery and silencing

Despite the extensive use of silica nanoparticles (SiO2NPs) in many fields, the results about their potential toxicity are still controversial. In this work, we have performed a systematic in vitro study to assess the biological impact of SiO2NPs, by investigating 3 different sizes (25, 60 and 115 nm) and 2 surface charges (positive and negative) of the nanoparticles in 5 cell lines (3 in adherence and 2 in suspension). We analyzed the cellular uptake and distribution of the NPs along with their possible effects on cell viability, membrane integrity and generation of reactive oxygen species (ROS). Experimental results show that all the investigated SiO2NPs do not induce detectable cytotoxic effects (up to 2.5 nM concentration) in all cell lines, and that cellular uptake is mediated by an endocytic process strongly dependent on the particle size and independent of its original surface charge, due to protein corona effects. Once having assessed the biocompatibility of SiO2NPs, we have evaluated their potential in gene delivery, showing their ability to silence specific protein expression. The results of this work indicate that monodisperse and stable SiO2NPs are not toxic, revealing their promising potential in various biomedical applications

Toxicity of citrate-capped AuNPs: an in vitro and in vivo assessment

In this study, we show that 15 nm citrate-capped AuNPs exert a remarkable toxicity in living systems. The assessment was performed by using well-characterized AuNPs, the combination of in vitro and in vivo models (namely two different cell lines and Drosophila melanogaster), exposure to low dosages of nanoparticles (in the sub-nanomolar concentration range), along with the application of several biological assays to monitor different aspects of the toxic effects, such as viability, genotoxicity, and molecular biomarkers

Identification of the different magnetic field contributions during a geomagnetic storm in magnetospheric and ground observations

Abstract. We used the empirical mode decomposition (EMD) to investigate the time variation of the magnetospheric and ground-based observations of the Earth's magnetic field during both quiet and disturbed periods. We found two timescale variations in magnetospheric data which are associated with different magnetospheric current systems and the characteristic diurnal orbital variation, respectively. On the ground we identified three timescale variations related to the solar-wind–magnetosphere high-frequency interactions, the ionospheric processes, and the internal dynamics of the magnetosphere. This approach is able to identify the different physical processes involved in solar-wind–magnetosphere–ionosphere coupling. In addition, the large-timescale contribution can be used as a local index for the identification of the intensity of a geomagnetic storm on the ground