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147 results on '"Megna G"'

4. Challenges and methodology for pre-processing measured and new rail profiles to efficiently simulate wheel-rail interaction in switches and crossings.

Author

Bezin, Y., Sambo, B., Magalhaes, H., Kik, W., Megna, G., and Costa, J. N.

Subjects
RAILROAD trains, RAILROAD crossings, INTERPOLATION
Abstract

This paper describes a methodology developed to systematically pre-process rail profile data from switches and crossings for railway vehicle dynamics simulation. The methodology accepts two data sources, unworn geometries from CAD drawings or worn geometries from digitised track measurements. The method addresses key challenges with the relative positioning and quality improvement of the input data and explains the necessary steps to ensure compatibility with the interpolation schemes used to represent the rail profile in certain multibody software. The case studies presented show how small misalignments in the processed digitised measurements affect simulation results and how simulations can help understand the qualitative evolution of switches and crossings rail profiles in a used track. This paper concludes that one of the most challenging tasks remains the automation of rail pre-processing for measured data because it is difficult to correct vertical and lateral misalignments of the profile cross-sections without a reference system. [ABSTRACT FROM AUTHOR]

Published
2023
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5. Effects of geometric track irregularities on vehicle dynamic behaviour when running through a turnout.

Author

Bosso, N., Bracciali, A., Megna, G., and Zampieri, N.

Subjects
RAILROAD trains, DYNAMIC loads, DYNAMIC simulation, SENSITIVITY analysis, VEHICLES, BOGIES (Vehicles)
Abstract

Railway vehicle dynamics is strongly affected by track irregularities, which can influence the safety and the running behaviour of the vehicle. The EN 13848-5:2017 standard provides the limits of track irregularities for standard track but does not states specific restrictions for switches and crossings. Furthermore, since turnouts have a limited length, their track geometric irregularities cannot be accurately described by stochastic functions usually adopted for railway vehicle dynamics simulations. Nevertheless, irregularities in railway turnouts, related to the non-uniform stiffness of the track support and to the variation of the rail profiles along the longitudinal direction should be considered in dynamic simulations, as they can generate large dynamic loads, strongly affecting the vehicle dynamics and running stability. The aim of the paper is to expand the Switches and Crossing benchmark exercise analysing the effect of several kinds of irregularity with different wavelengths and amplitudes on a complete turnout on the main quantities related to the vehicle dynamics. The influence of each defect on each quantity is estimated through a post-processing sensitivity analysis based on power spectral density calculation. This sensitivity analysis is hence used to combine different types of defects in order to detect irregularity combinations that could compromise running safety. [ABSTRACT FROM AUTHOR]

Published
2023
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23. The Role of Neuroinflammation in Severe Acquired Brain Injuries. Preliminary Results on Subacute and Chronic Patients

Author

Solano, J. Navarro, primary, Damiani, S., additional, Munno, I., additional, Guastamacchia, F., additional, Anglani, S., additional, Baccaro, M.L., additional, Benedetto, G., additional, Megna, M., additional, Ranieri, M., additional, De Vargas, C. Echevarria Ruiz, additional, Lancioni, G.E., additional, and Megna, G., additional

Published
2009
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24. Physical Exercise and the Immune System

Author

Ranieri, M., primary, Megna, M., additional, Lancioni, G.E., additional, Jirillo, E., additional, Amico, A.P., additional, Nardulli, M., additional, Stasi, M., additional, Ianieri, G., additional, Saggini, A., additional, and Megna, G., additional

Published
2009
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25. Botulinum Toxin in Cerebral Child Palsy

Author

Ianieri, G., primary, Saggini, R., additional, Marvulli, R., additional, Tondi, G., additional, Aprile, A., additional, Ranieri, M., additional, Di Teo, L., additional, Altini, S., additional, Lancioni, G.E., additional, Goffredo, L., additional, Megna, M., additional, and Megna, G., additional

Published
2009
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38. Successful extension of assessment and rehabilitation intervention for an adolescent with postcoma multiple disabilities through a learning setup

Author

Lancioni, G. E., Marta OLIVETTI, Oliva, D., Signorino, M., Tommaso, M., Megna, G., Singh, N. N., O’reilly, M. F., and Sigafoos, J.

Subjects
Male, learning, Adolescent, Movement, Persistent Vegetative State, coma, Choice Behavior, rehabilitation, Communication Aids for Disabled, persistent vegetative state, Physical Stimulation, Humans, Disabled Persons, Forehead
Abstract

Prior to the beginning of this study, the participant (an adolescent with postcoma multiple disabilities) had learned to use a forehead-skin response to access environmental stimuli. These learning data seemed to indicate a minimally conscious state (i.e., awareness of the link between response and stimuli) in spite of 1) a previous diagnosis of postcoma vegetative state; and 2) concomitant electrophysiological measurement showing no evidence of a passive P300 response and of mismatch negativity. The present study was an effort to extend the early learning investigation with two additional responses and related stimuli to broaden learning evidence and ascertain possible choice behavior. Results indicated that the participant learned the new responses and also provided evidence of choice behavior. These data were discussed in terms of the usefulness of the learning paradigm in the assessment and rehabilitation of persons with postcoma multiple disabilities and consciousness disorders.

42. Urodynamic evaluation of 12 ataxic subjects: Neurophysiopathologic considerations

Author

Nardulli R, Monitillo V, Losavio E, Fiore P, Giuseppe Nicolardi, and Megna G

Subjects
Adult, Male, Urodynamics, Cerebellar Ataxia, Friedreich Ataxia, Reflex, Urinary Bladder, Humans, Female, Middle Aged, Urinary Bladder, Neurogenic, Aged
Abstract

Twelve ataxic subjects (seven with Friedreich's heredo-ataxia and five with a cerebellar vascular or traumatic lesion) were examined by way of urodynamic evaluation. The results explain the role the cerebellum plays in the modulation of the micturition reflex and confirm the importance of bilateral encephalic damage in causing vesico-sphincteral malfunctioning and the important role of the lateral myelon cords in transporting bladder proprioceptive sensitivity.

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