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.
Carlos Garcia Orden J.,Technical University of Madrid |
Cuenca Queipo J.,INECO
Journal of Computational and Nonlinear Dynamics | Year: 2017
This paper describes a very simple beam model, amenable to be used in multibody applications, for cases where the effects of torsion and shear are negligible. This is the case of slender rods connecting different parts of many space mechanisms, models useful in polymer physics, computer animation, etc. The proposed new model follows a lumped parameter method that leads to a rotation-free formulation. Axial stiffness is represented by a standard nonlinear truss model, while bending is modeled with a force potential. Several numerical experiments are carried out in order to assess accuracy, which is usually the main drawback of this type of approach. Results reveal a remarkable accuracy in nonlinear dynamical problems, suggesting that the proposed model is a valid alternative to more sophisticated approaches. Copyright © 2017 by ASME.
Salvador P.,Universidad Politécnica de Ingeniería |
Real J.,Universidad Politécnica de Ingeniería |
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.
Pujadas M.,CIEMAT |
Nunez L.,CIEMAT |
Remote Sensing of Environment | Year: 2011
In this work we examine the possibility of using satellite remote sensors for the detection of air traffic emissions produced during the en-route segment of flight in the Upper Troposphere/Lower Stratosphere region (8000-12,000m). NO2 has been considered as the tracer of aircraft plumes with highest possibility of being successfully detected from space. An analysis of the technical potential of the current orbital sensors capable of measuring NO2 in the proximity of the tropopause has been conducted. In order to estimate an upper bound for the NO2 column related to aircraft emissions, the Canary Islands Corridor has been selected for conducting a simple emission calculation exercise based on real air traffic and operational data, assuming an ideal atmospheric scenario. The results obtained in this approximation have been compared to the actual information retrieved from space sensors. An in-depth inspection of the NO2 column data for two particular areas (Canary Islands Corridor and North Atlantic Flight Corridor) obtained in recent years by SCIAMACHY and OMI has also been carried out. The general conclusions of this viability study are not optimistic. The estimated maximum NO2 column value attributable to aircraft emissions at cruise altitudes were lower than the detection limits associated with SCIAMACHY and OMI for NO2 column measurements. As a result, detecting and quantifying the actual NO2 levels in aircraft corridors by space remote sensing is a very challenging task. © 2011 Elsevier Inc.
Tebar J.,ADIF |
Underground - The Way to the Future: Proceedings of the World Tunnel Congress, WTC 2013 | Year: 2013
The article describes the works carried out with a mixed EPB, in the execution of the Tunnels of Quejigares of the High Speed Line Antequera - Granada, in Spain. The Project, initially designed to execute it by conventional methods and double track, was decided to realize it with a single shield EPB transformed into a mixed EPB, being able to excavate in soils and rock. The predominant grounds in the alignment are clays and sand, with sections of limestone rock and sections of argillaceous matrix with limestone rock and conglomerates interleaves. In the article, it will be describe the most excellent and interesting aspects of the tunnels mentioned, as much in the conception and writing of the Project, modifications and repairs of the tunnel boring machine and the behavior during the execution of the tunnels. The ways of work of the TBM in the different types of ground will be described: rock, soil and mixed ground. The incidences of geologic-geotechnical and hydrogeological type will be analyzed, that in some cases are conditional not only the design, but also the execution of works. © 2013 Taylor & Francis Group.
Capilla R.,Rey Juan Carlos University |
Hinchey M.,University of Limerick |
ACM International Conference Proceeding Series | Year: 2015
Feature models and their extensions have been proposed and used over the past 20 years for modeling the commonality and variability of software systems. However, the increasing runtime demands and post-deployment configuration procedures of selfadaptive, context-aware and pervasive systems has brought the need for modeling context features. In addition, many critical systems that demand stringent collaborative features at runtime need also to share information dynamically. In this research-inprogress paper, we sketch our vision of where feature modeling should go to support collaborative aspects of systems. Our proposal suggests identifying and annotating context features models with collaborative information that becomes particularly useful for critical and swarm-based systems that require information exchange at runtime. Copyright 2015 ACM.
Andres A.,Ineco |
Civil-Comp Proceedings | Year: 2014
This paper summarizes the AV-RAMS project. This paper shows the results obtained by analysing data from different sources. These results have made possible the study of parameters reliability, availability, maintainability and safety (RAMS) of the infrastructure and superstructure of a high speed railway system. This is an innovative study, as rarely is the expression RAMS used with systems that do not concern electrical engineering, as is the case of the infrastructure and superstructure. Explained here is one of the mayor difficulties of the AV-RAMS project, because RAMS studies are almost always related with the brand of electrical engineering, machinery, components, etc. as the regulations are not intended for different systems, unlike the track infrastructure and superstructure. The aim of the study of the different events and failure modes of the infrastructure and superstructure is to improve the maintenance processes of a high speed railway system. With the conclusions obtained in the project AV-RAMS, a cost analysis and the integration of this project with RAMS studies of other railway systems, a theoretical model is achieved which lets us redefine and improve the railway system. © Civil-Comp Press, 2014.
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.
Real J.,Universidad Politécnica de Ingeniería |
Martinez P.,Universidad Politécnica de Ingeniería |
Montalban L.,Universidad Politécnica de Ingeniería |
Mathematical and Computer Modelling | Year: 2011
The recent growth in the use of the railway and particularly that of the tram in urban areas highlights the need to investigate and mitigate the harmful effects associated with these means of transport. The vibrations caused by passing vehicles can be a source of vibration and may damage buildings close to the line. This article aims to develop an analytical mathematical model for predicting the ground vibrations caused by the passing of trams along a slab track. The model is based on the wave equation and is solved in the frequency domain through the Fourier Transform. The loads caused by the vehicle are calculated using a quarter car model. The model is calibrated and validated with real data collected along the tram network of Alicante (Spain), providing a useful tool for future research on the transmission of ground vibrations. © 2011 Elsevier Ltd.
Perez J.C.,INECO |
Abad J.N.,INECO |
SHMII 2015 - 7th International Conference on Structural Health Monitoring of Intelligent Infrastructure | Year: 2015
This article develops the use of new fiber optic techniques (all equipment and sensors) for the Monitoring of medium-sized and large viaducts, where the great number of measuring points as well as their location along the structure would require from a conventional installation (voltage and current sensors) the use of numerous long cables for the connection. This would complicate the installation and increase its cost, and it would also have a pernicious effect to the signal quality during transmission. We have chosen as a practical case study the Beltrán Viaduct, as it is a singular bridge within the Guadalajara - Colima highway that lies on a seismic area and has a length beyond 140 meters. It is a viaduct with a pre-stressed concrete slab with box girder cross section at a variable height and concrete pillars. The viaduct has a total length of 297.49m, four spans the length of which is 76.30 + 12.40 + 134.90 + 76.59 meters. The measurement points and parameters focus the study and behaviour control of the pillar, as well as the overall behaviour of abutment displacements and pillars exposed to environmental phenomena and seismic activity. Stress, tilt and acceleration are measured on different sections on a continuous way during the circulation of all vehicles, all day, with the acquisition frequency needed to study the behaviour and dynamic control. The study was carried out during a one year period, allowing for the verification of measured results against the outcomes of the theoretical model initially developed. Finally the results measured are presented, as well as the typology and specificities of the measures, the Digital Signal Processing and Analysis, and the possibilities of presenting data in real time on a website. (Figure Presented). © 2015, International Society for Structural Health Monitoring of Intelligent Infrastructure, ISHMII. All rights reserved.