Palmero N.M.,INECO |
Vardy A.,University of Dundee
Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit | Year: 2014
An inconvenient consequence of the UIC health and safety criterion for allowable pressure changes in railway tunnels is highlighted. It is shown that the criterion limits allowable speeds in long tunnels with large changes of elevation much more than it does in equivalent tunnels with small changes in elevation. The constraint is especially strong for trains travelling uphill, but it can also exist for trains travelling downhill. Possible ways of avoiding the problem without reducing speed are considered and are found to be practicable in some cases. However, they are of uncertain suitability because they rely on exploiting a particular feature of the safety criterion in a manner that is unlikely to have been intended when it was mandated. In addition, attention is drawn to an ambiguity inherent in the application of the criterion to certain types of tunnel. Suggestions are made for simple modifications to the criterion and comparisons are made with conditions experienced routinely in commercial aviation. © IMechE 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.
Arnaldo Valdes R.M.,Polytechnic University of Mozambique |
Gomez Comendador F.,INECO |
Mijares Gordun L.,Senasa |
Saez Nieto F.J.,Polytechnic University of Mozambique
Safety Science | Year: 2011
The risks of landing overrun (LDOR - LanDing OverRun), Take-off Overrun (TOOR - Take-Off OverRun) and landing undershoot (LDUS - LanDing UnderShoot) are dependent on multiple factors related to operating conditions. These include wind, runway surface conditions, landing or take-off distances required, the presence of obstacles, runway distance available, the existence and dimensions of runway safety areas. In this paper we propose risk models for runway overrun and landing undershoot, using a probabilistic approach. These models are supported by historical data on accidents in the area around the runway and will enable us to determine if the risk level is acceptable or whether action must be taken to mitigate such risks at a given airport. Furthermore, these models permit comparison of the results of different risk mitigation actions in terms of operational risk and safety. The principal advantage of this method is the high quality results obtained for a limited investment in terms of time, computing power and data. As such the method is extremely practical and easy to apply in aerodrome planning, development and operation. © 2010 Elsevier Ltd.
Salvador P.,Universidad Politecnica de Ingenieria |
Real J.,Universidad Politecnica de Ingenieria |
Zamorano C.,Fundacion Caminos de Hierro |
Mathematical and Computer Modelling | Year: 2011
In recent years, ground vibrations have become an important issue due to the growing awareness of the society about environmental living conditions. In this way, vibrations caused by trains running near houses or workplaces are considered disturbing for residents. Within this framework, this paper presents a procedure to estimate the vibration path caused by the passing of a train. In order to achieve this, the equations which describe the physical phenomenon are set in the frequency and wavenumber domain and solved by using the Fourier Transform. The obtained analytical solution is transformed back into the time and space domain by means of the Fourier series. The obtained theoretical results are compared with experimental measurements carried out in the Madrid-Barcelona High Speed Line in order to analyse the performance of this procedure. © 2010.
Valdes R.M.A.,Polytechnic University of Mozambique |
Gomez Comendador F.G.,INECO
Journal of Aircraft | Year: 2011
Civil aviation has a long-standing tradition of investigating accidents, which contributes to making aviation one of the safest forms of transport. The obligation to investigate accidents is enshrined in the Chicago Convention of 1944. Recognizing the importance of accident investigation, the European Union adopted the principles governing the investigation of civil aviation accidents. But the European Union rules on investigating air accidents need to be updated to reflect the current realities of Europe's aviation market and the complexity of the global aviation industry. Accordingly, the European Commission has been working on a regulation on the investigation and prevention of accidents and incidents in civil aviation. Reasons behind this new regulation are presented in this paper, together with a detailed explanation of its main contents, an assessment of their impact, and their expected benefits. © 2010 by the American Institute of Aeronautics and Astronautics, Inc.
Riccio P.M.,University of Buenos Aires |
Klein F.R.,University of Buenos Aires |
Cassara F.P.,University of Buenos Aires |
Giacomelli F.M.,University of Buenos Aires |
And 8 more authors.
Neurology | Year: 2013
Background: Based on the higher frequency of paroxysmal atrial fibrillation during night and early morning hours, we sought to analyze the association between newly diagnosed atrial fibrillation and wake-up ischemic cerebrovascular events. Methods: We prospectively assessed every acute ischemic stroke and TIA patient admitted to our hospital between 2008 and 2011. We used a forward step-by-step multiple logistic regression analysis to assess the relationship between newly diagnosed atrial fibrillation and wake-up ischemic stroke or TIA, after adjusting for significant covariates. Results: The study population comprised 356 patients, 274 (77.0%) with a diagnosis of acute ischemic stroke and 82 (23.0%) with TIA. A total of 41 (11.5%) of these events occurred during night sleep. A newly diagnosed atrial fibrillation was detected in 27 patients of 272 without known atrial fibrillation (9.9%). We found an independent association between newly diagnosed atrial fibrillation and wake-up ischemic stroke and TIA (odds ratio 3.6, 95% confidence interval 1.2-7.7, p = 0.019). Conclusions: The odds of detecting a newly diagnosed atrial fibrillation were 3-fold higher among wake-up cerebrovascular events than among non-wake-up events. The significance of this independent association between newly diagnosed atrial fibrillation and wake-up ischemic stroke and TIA and the role of other comorbidities should be investigated in future studies. © 2013 American Academy of Neurology.