977 resultados para UAM, eVTOL, velivoli elettrici, tilt rotation, batterie
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Studio e Progettazione di un sistema di sicurezza ed una legge di controllo per UAV di tipo quadcopter.
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L'indipendenza dai combustibili fossili è uno degli argomenti maggiormente trattati negli ultimi anni e lo sviluppo di tecnologie atte a produrre energia attraverso fonti rinnovabili è uno dei punti cruciali della ricerca moderna. L'utilizzo dei veicoli elettrici nel quotidiano rappresenta una delle vie principali per l'abbandono delle fonti non rinnovabili, tuttavia siamo ancora in presenza di qualche limite. Una delle principali ragioni per cui gli automobilisti sono restii ad utilizzare le auto elettriche è quella che in inglese viene definita Range Anxiety, ossia la preoccupazione di non riuscire a raggiungere la propria meta con l'autonomia residua del veicolo. Altri fattori che contribuiscono a scoraggiare gli automobilisti sono i lunghi tempi di ricarica e dove effettuare queste ultime. Per cercare di ridurre queste problematiche nel seguente elaborato viene descritto lo sviluppo di un applicazione per sistema Android, con lo scopo di simulare dei percorsi inseriti dall'utente come se venissero effettuati utilizzando un veicolo elettrico: l'applicativo, sfruttando un servizio esterno fornirà all'utente tutti i dati del percorso, come ad esempio dove effettuare una ricarica. Di seguito viene illustrato l'utilizzo dell'applicativo, la sua architettura, come è stato sviluppato e le sue future estensioni.
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La tesi tratta la teoria unificata degli azionamenti in correnti alternata.
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Studio riguardante le prestazioni di autonomia oraria e una metotodologia analitica per massimizzare il tempo di volo di velivoli multirotore, effettuato considerando tutte le variabili di progetto in condizioni di hovering. Si è ottenuta una formulazione per un primo dimensionamento del velivolo in condizioni di massima autonomia oraria.
An examination chair to measure internal rotation of the hip in routine settings: a validation study
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OBJECTIVE: To determine the performance of a newly developed examination chair as compared with the clinical standard of assessing internal rotation (IR) of the flexed hip with a goniometer.
METHODS: The examination chair allowed measurement of IR in a sitting position simultaneously in both hips, with hips and knees flexed 90 degrees, lower legs hanging unsupported and a standardized load of 5 kg applied to both ankles using a bilateral pulley system. Clinical assessment of IR was performed in supine position with hips and knees flexed 90 degrees using a goniometer. Within the framework of a population-based inception cohort study, we calculated inter-observer agreement in two samples of 84 and 64 consecutive, unselected young asymptomatic males using intra-class correlation coefficients (ICC) and determined the correlation between IR assessed with examination chair and clinical assessment.
RESULTS: Inter-observer agreement was excellent for the examination chair (ICC right hip, 0.92, 95% confidence interval [CI] 0.89-0.95; ICC left hip, 0.90, 95% CI 0.86-0.94), and considerably higher than that seen with clinical assessment (ICC right hip, 0.65, 95% CI 0.49-0.77; ICC left hip, 0.69, 95% CI 0.54-0.80, P for difference in ICC between examination chair and clinical assessment
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Mechanical stress controls a broad range of cellular functions. The cytoskeleton is physically connected to the extracellular matrix via integrin receptors, and to the nuclear lamina by the LINC complex that spans both nuclear membranes. We asked here how disruption of this direct link from the cytoskeleton to nuclear chromatin affects mechanotransduction. Fibroblasts grown on flexible silicone membranes reacted to cyclic stretch by nuclear rotation. This rotation was abolished by inhibition of actomyosin contraction as well as by overexpression of dominant-negative versions of nesprin or sun proteins that form the LINC complex. In an in vitro model of muscle differentiation, cyclic strain inhibits differentiation and induces proliferation of C2C12 myoblasts. Interference with the LINC complex in these cells abrogated their stretch-induced proliferation, while stretch increased p38 MAPK and NFkappaB phosphorylation and the transcript levels of myogenic transcription factors MyoD and myogenin. We found that the physical link from the cytoskeleton to the nuclear lamina is crucial for correct mechanotransduction, and that disruption of the LINC complex perturbs the mechanical control of cell differentiation.
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Isolated lateral malleolar fractures usually result from a supination-external rotation (SER) injury and may include a deltoid ligament rupture. The necessity of operative treatment is based on the recognition of a relevant medial soft-tissue disruption. Currently used tests to assess ankle stability include manual stress radiographs and gravity stress radiographs, but seem to overestimate the need for fracture fixation.
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In patients with a rotator cuff-deficient shoulder, a combined loss of active elevation and external rotation (CLEER) can occur when both the infraspinatus and teres minor muscles are absent. A reverse shoulder arthroplasty (RSA) can restore active elevation in these patients but cannot restore active external rotation because there are no other external rotator cuff muscles. We hypothesized that a modified L'Episcopo procedure (latissimus dorsi [LD] and teres major [TM] transfer) with a simultaneous RSA would restore shoulder function and activities of daily living (ADLs).
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Early prediction of massive transfusion (MT) is critical in the management of severely injured trauma patients. Variables available early after injury including physiologic, laboratory, and rotation thromboelastometric (ROTEM) parameters were evaluated as predictors for the need of MT.
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To describe the mechanics and possible clinical importance of left ventricular (LV) rotation, exemplify techniques to quantify LV rotation and illustrate the temporal relationship of cardiac pressures, electrocardiogram and LV rotation.
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We describe the multidisciplinary findings in a pre-Columbian mummy head from Southern Peru (Cahuachi, Nazca civilisation, radiocarbon dating between 120 and 750 AD) of a mature male individual (40-60 years) with the first two vertebrae attached in pathological position. Accordingly, the atlanto-axial transition (C1/C2) was significantly rotated and dislocated at 38° angle associated with a bulging brownish mass that considerably reduced the spinal canal by circa 60%. Using surface microscopy, endoscopy, high-resolution multi-slice computer tomography, paleohistology and immunohistochemistry, we identified an extensive epidural hematoma of the upper cervical spinal canal-extending into the skull cavity-obviously due to a rupture of the left vertebral artery at its transition between atlas and skull base. There were no signs of fractures of the skull or vertebrae. Histological and immunohistochemical examinations clearly identified dura, brain residues and densely packed corpuscular elements that proved to represent fresh epidural hematoma. Subsequent biochemical analysis provided no evidence for pre-mortal cocaine consumption. Stable isotope analysis, however, revealed significant and repeated changes in the nutrition during his last 9 months, suggesting high mobility. Finally, the significant narrowing of the rotational atlanto-axial dislocation and the epidural hematoma probably caused compression of the spinal cord and the medulla oblongata with subsequent respiratory arrest. In conclusion, we suggest that the man died within a short period of time (probably few minutes) in an upright position with the head rotated rapidly to the right side. In paleopathologic literature, trauma to the upper cervical spine has as yet only very rarely been described, and dislocation of the vertebral bodies has not been presented.
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As the number of solutions to the Einstein equations with realistic matter sources that admit closed time-like curves (CTC's) has grown drastically, it has provoked some authors [10] to call for a physical interpretation of these seemingly exotic curves that could possibly allow for causality violations. A first step in drafting a physical interpretation would be to understand how CTC's are created because the recent work of [16] has suggested that, to follow a CTC, observers must counter-rotate with the rotating matter, contrary to the currently accepted explanation that it is due to inertial frame dragging that CTC's are created. The exact link between inertialframe dragging and CTC's is investigated by simulating particle geodesics and the precession of gyroscopes along CTC's and backward in time oriented circular orbits in the van Stockum metric, known to have CTC's that could be traversal, so the van Stockum cylinder could be exploited as a time machine. This study of gyroscopeprecession, in the van Stockum metric, supports the theory that CTC's are produced by inertial frame dragging due to rotating spacetime metrics.