106 research outputs found
Applicazioni di ventose in robotica mobile
No full textLe ventose sono un utile strumento, leggero ed economico, per consentire l’adesione a pareti o soffitti di robot arrampicatori. L’utilità di questi ultimi risulta evidente in particolare in situazioni in cui l’intervento umano è rischioso o costoso. In questi ultimi anni vari ricercatori hanno sviluppato dispositivi che permettono l’intervento per la pulizia, l’ispezione, la manutenzione in differenti ambienti. Sebbene non vi sia ancora un largo uso di questi robot, sono state poste le premesse per una loro futura ampia diffusione
AN EXPERIMENTAL STUDY ON A HIGH-SPEED ROTOR SUPPORTED BY AIR BEARINGS MOUNTED ON O-RINGS
No full text
The Challenges of Oil Free Bearings in Micro-turbomachinery
No full textAmong all types of bearings, gas bearings are the most environmental friendly supports as they do not need to be lubricated with mineral oil. The air or the gaseous working fluid used in micro-turbomachinery are used to lubricate the bearings and realize the supporting task. Due to their characteristics, they cannot replace the other bearings in all applications; however, the research is always working in order to broaden the boundaries of gas bearings. This paper is aimed at describing the most promising application domains in which gas bearings are challenging and gives a survey on all types of gas bearings, discussing their pros and cons. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG
Studio, realizzazione e sperimentazione di prototipi di muscoli pneumatici innovativi a base tessile
No full textIL PRESENTE ARTICOLO PRESENTA ALCUNI PROTOTIPI INNOVATIVI STUDIATI, REALIZZATI E SPERIMENTATI PRESSO IL DIPARTIMENTO DI INGEGNERIA MECCANICA E AEROSPAZIALE DEL POLITECNICO DI TORINO. LA STRUTTURA DI TALI MUSCOLI È DI TIPO TESSILE AL FINE DI RENDERLI FACILMENTE ADATTABILI AD APPLICAZIONI A DIRETTO CONTATTO CON IL CORPO UMANO QUALI DISPOSITIVI PER AUSILIO DEI MOVIMENTI O PER RIABILITAZIONE
HIGH SPEED ROTOR WITH AIR BEARINGS MOUNTED ON FLEXIBLE SUPPORTS: TEST BENCH AND EXPERIMENTAL RESULTS
No full textA test bench for rotors supported by air bearings floating on O-rings is designed in order to study the whirl phenomenon and characterize the stability threshold with damping elements mounted on bearings. The work includes a description of the test bench and some preliminary experimental results. A rotor of 1 kg mass and 37 mm diameter is rotated up to 75,000 rpm by an air turbine machined on the rotor. Capacitance probes, placed in two radial planes, allow orbit scanning of both the rotor and the bushing at different rotating speeds and suitable load devices permit measurement of the static and dynamic stiffness of the rotor-bearing system. Curves of rotational response using rubber O-rings of three different materials are shown and compared. Also presented are the Fourier spectra of the signals for rotor displacement. The phenomenon of whirl instability is shown in terms of whirl frequency and orbit amplitudes of the rotor and bearings. The effects of both supply pressure and angular velocity on the stability threshold are show
COVID-19 mortality among migrants living in Italy
No full textWe aimed to compare COVID-19-specific and all-cause mortality rates among natives and migrants in Italy and to investigate the clinical characteristics of individuals dying with COVID-19 by native/migrant status. The mortality rates and detailed clinical characteristics of natives and migrants dying with COVID-19 were explored by considering the medical charts of a representative sample of patients deceased in Italian hospitals (n = 2,687) between February 21st and April 29th, 2020. The migrant or native status was assigned based on the individual’s country of birth. The expected all-cause mortality among natives and migrants living in Italy was derived by the last available (2018) data-set provided by the Italian National Institute of Statistics. Overall, 68 individuals with a migration background were identified. The proportions of natives and migrants among the COVID-19-related deaths (97.5% and 2.5%, respectively) were similar to the relative all-cause mortality rates estimated in Italy in 2018 (97.4% and 2.6%, respectively). The clinical phenotype of migrants dying with COVID-19 was similar to that of natives except for the younger age at death. International migrants living in Italy do not have a mortality advantage for COVID-19 and are exposed to the risk of poor outcomes as their native counterparts
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