DYNAMIC MODELLING OF HIGH SPEED BALLASTED RAILWAY TRACKS: ANALYSIS OF THE BEHAVIOUR

[EN] The aim of the paper is to present a numerical model for a ballasted railway track that includes the dynamic effect of a moving train load and predicts the values of the vertical stiffness of the infrastructure. This model is therefore deemed to be a tool for the evaluation of the state of the track during service situations as well as a predictive model of the behaviour of the system. Consequently, it will be very useful when sizing the cross section of a new railway line is required. The main modelling tool is the finite element method. In regard to this, the application of damping elements to avoid the elastic wave reflection on the boundaries of the numerical domain will be studied. The proposed dynamic analysis consider the change in time of the value of the train load, but not the change in position along the tracks. In the end, a set of suggestions for the numerical model with moving loads will be summarize aiming for the mitigation of the unusual behaviour of the contact surface between the ballast and the sleepers.Gallego, I.; Rivas, A.; Sánchez-Cambronero, S.; Lajara, J. (2016). DYNAMIC MODELLING OF HIGH SPEED BALLASTED RAILWAY TRACKS: ANALYSIS OF THE BEHAVIOUR. En XII Congreso de ingeniería del transporte. 7, 8 y 9 de Junio, Valencia (España). Editorial Universitat Politècnica de València. 615-623. https://doi.org/10.4995/CIT2016.2015.4218OCS61562

A Continuous Dynamic Traffic Assignment Model From Plate Scanning Technique

[EN] This paper presents a methodology for the dynamic estimation of traffic flows on all links of a network from observable field data assuming the first-in-first-out (FIFO) hypothesis. The traffic flow intensities recorded at the exit of the scanned links are propagated to obtain the flow waves on unscanned links. For that, the model calculates the flow-cost functions through information registered with the plate scanning technique. The model also responds to the concern about the parameter quality of flow-cost functions to replicate the real traffic flow behaviour. It includes a new algorithm for the adjustment of the parameter values to link characteristics when its quality is questionable. For that, it is necessary the a priori study of the location of the scanning devices to identify all path flows and to measure travel times in all links. A synthetic network is used to illustrate the proposed method and to prove its usefulness and feasibilityRivas, A.; Gallego, I.; Sánchez-Cambronero, S.; Ruiz-Ripoll, L.; Barba, R. (2016). A Continuous Dynamic Traffic Assignment Model From Plate Scanning Technique. En XII Congreso de ingeniería del transporte. 7, 8 y 9 de Junio, Valencia (España). Editorial Universitat Politècnica de València. 1132-1141. https://doi.org/10.4995/CIT2016.2015.4215OCS1132114

Proposal of a New Methodology for Traffic Flows Estimation through the Optimization of the Device Location and the Route Enumeration

In recent years, different techniques to address the problem of observability in traffic networks have been proposed in multiple research projects, being the technique based on the installation of automatic vehicle identification devices (AVI), one of the most successful in terms of results but to in turn, complex in terms of its combined use with other methods. Most of the current methods do not consider the possibility of installing a series of plate scanning devices in the elements of a network (nodes, links), such that they allow us to obtain a better definition of the O-D matrix and obtain a better set of data for the analysis and estimation of traffic flows for different scenarios. With these antecedents, a new methodology is proposed that jointly considers: 1) a device location model for a given traffic network according to criteria established by the analyst and, 2) a model that establish the best set of routes to be considered in the estimation step. An example of the application of this methodology for a real study network in Ciudad Real is shown, where a sensitivity analysis is applied to test the influence of a set of relevant variables

Stir Casting Routes for Processing Metal Matrix Syntactic Foams: A Scoping Review

Metal matrix syntactic foams (MMSFs) are advanced lightweight materials constituted by a metallic matrix and a dispersion of hollow/porous fillers. Physical and mechanical properties can be fitted regarding matrix and filler properties and processing parameters. Their properties make them potential materials for sectors where density is a limiting parameter, such as transport, marine, defense, aerospace, and engineering applications. MMSFs are mainly manufactured by powder metallurgy, infiltration, and stir casting techniques. This study focuses on the current stir casting approaches and on the advances and deficiencies, providing processing parameters and comparative analyses on porosity and mechanical properties. PRISMA approaches were followed to favor traceability and reproducibility of the study. Stir casting techniques are low-cost, industrially scalable approaches, but they exhibit critical limitations: buoyancy of fillers, corrosion of processing equipment, premature solidification of molten metal during mixing, cracking of fillers, heterogeneous distribution, and limited incorporation of fillers. Six different approaches were identified; four focus on limiting buoyancy, cracking, heterogeneous distribution of fillers, and excessive oxidation of sensitive matrix alloys to oxygen. These improvements favor reaching the maximum porosity of 54%, increasing the fillers size from a few microns to 45 mm, reducing residual porosity by ±4%, synthesizing bimodal MMSFs, and reaching maximum incorporation of 74 vol%.</jats:p

Metodología para modelizar una red de tráfico en la que se van a obtener datos mediante la técnica del escaneo de matrículas

[ES] En el presente artículo se aborda el problema de modelizar una red de tráfico para poder aplicar la técnica del escaneo de matrículas para estimar flujos en ruta, y por tanto obtener la matriz Origen-Destino así como la asignación de la red. Para llevar a cabo dicha modelización se plantea una metodología que trata de manera global la simplificación de la red y que tiene como base la reducción del número de rutas mediante la eliminación de pares Origen-Destino que no tengan una demanda relevante. Dicha simplificación tiene un enfoque práctico muy diferente de la visión tradicional de zonificación y disposición de centroides dentro de la red y que permitirá imbricarla con los modelos de ubicación de dispositivos de escaneo. La metodología permite detectar aquellos arcos de la red que son afectados por la simplificación y las consecuencias sobre la estimación de flujos que puedan derivarse de dicha afección. Con todo ello, se puede establecer una priorización en la ubicación de los equipos de escaneo que permitirá hacer una reconstrucción más fiable de los flujos de la red. Se ha empleado una red basada en la denominada red Nguyen-Dupuis como ejemplo de aplicación de la metodología desarrollada. A través del mismo se irá aclarando paso por paso cada una de las fases del método.Sánchez Cambronero, S.; Rivas Álvarez, A.; Barba Contreras, R.; Ruiz Ripoll, L.; Gallego Giner, M.; Menéndez Martinez, J. (2016). Metodología para modelizar una red de tráfico en la que se van a obtener datos mediante la técnica del escaneo de matrículas. En XII Congreso de ingeniería del transporte. 7, 8 y 9 de Junio, Valencia (España). Editorial Universitat Politècnica de València. 1142-1154. https://doi.org/10.4995/CIT2016.2015.4216OCS1142115

Developing speaking competences in technical English for Spanish civil engineering students

[EN] Traditionally, Spanish schools of civil engineering provide their students a class on “Technical English” in order to develop their language skills. However, this class does not cover all the skills that the student would need in the labor market and mainly focuses in the reading and writing skills, and in a lower degree in the speaking and listening ones. This paper proposes a series of innovative and informal training activities (cine-forum on technical civil engineering topics and role playing on real professional situations) that allow Spanish civil engineering students to develop English skills that can rarely be worked in the classroom (i.e. speaking, negotiating and conversing), encouraging debate, participation, and fostering their self-confidence to speak about technical-English topics in public. Although the students’ level of English is much lower than expected, they all agree on the importance of technical English for their future career. The results also show the students’ lack in skills that are difficult to train in regular classes (speaking and talking). Consequently, this situation would require to provide complementary activities like the ones suggested in this project in order to develop these skills and increase the students’ demand for engineering classes taught in English.Romero De Ávila Serrano, V.; Diaz García, S.; Asensio Sánchez, L.; Lozano Galant, JA.; Moyano Enríquez De Salamanca, A.; Porras Soriano, R.; Poveda Bautista, E.... (2017). Developing speaking competences in technical English for Spanish civil engineering students. En Proceedings of the 3rd International Conference on Higher Education Advances. Editorial Universitat Politècnica de València. 1228-1236. https://doi.org/10.4995/HEAD17.2017.55641228123

Developing Students’ Communication in Technical English with Project Based Learning Methodology

Technical communication is an extremely important soft skill for civil engineers at the workplace. Due to globalization trends this technical communication often should be performed in English. If we join the fact that undergraduate engineering programs in Spain have been taught exclusively in Spanish, with which in addition, in rare cases those programs provide intentionally placed discipline-specific technical communication experiences, this all amounts to a major problem, regarded as an obstacle that limit undergraduates’ opportunities to work abroad. Aware of this problem, some schools provide their students with a brief course on “Technical English”. However, this course does not cover all the skills that the student would need in the labour market, such as speaking and listening abilities. This paper promotes an innovative teaching methodology that allows Spanish Civil Engineering students to hone English communication skills through “Lunch&Movies” sessions. In each session a documentary about technical Civil Engineering topics is shown. After the screening, students work in small inter-cohort groups with a guiding lecturer. These groups debate on different questions related to the video, encouraging participation, and fostering their self-confidence to talk about technical English topics in public. Different surveys were developed to demonstrate the students’ interest in learning technical English, and to evaluate the benefit for the attendees and their achievements. The results show that the students are conscious of the importance of technical English for their future careers, and most of them improved their initial level as the sessions progressed and they gained confidence in the foreign language. Also, through a pilot subject in English, it was demonstrated that the participants of the “Lunch&Movies” sessions obtained better oral qualifications than those who did not participate. In fact, the overall results indicated that Lunch & Movie sessions can improve students' technical oral skills as well as their own perceptions of their abilities

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

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Long-term observations as a key tool for the assessment of environmental changes in Las Tablas de Daimiel: LTER-Daimiel

[EN] Most ecological processes can only be understood from a long-time perspective. Ecosystems are changing in such a complex way that we are still trying to identify how and at what rate they are changing according to the complex network of stressors that impinges on them. The existing longterm observations in the LTER-Daimiel node allow us to assess the main causes and effects of major environmental changes in Las Tablas de Daimiel for the past 70 years. We show three examples of the validity of long-term observations as opposed to short-term records to assess the effects of various environmental impacts occurring in the wetland.[ES] La mayor parte de los procesos ecológicos sólo pueden entenderse desde una perspectiva temporal larga. Los ecosistemas están cambiando de un modo tan complejo que todavía estamos intentando detectar cómo lo hacen y a qué ritmo ante la compleja red de estresores a que están sometidos. Las observaciones a largo plazo existentes en el nodo LTER-Daimiel nos permiten evaluar las causas y los efectos de los principales cambios ambientales ocurridos en Las Tablas de Daimiel durante los últimos 70 años. En este trabajo presentamos tres ejemplos que ponen de manifiesto la validez de las observaciones a largo plazo en la interpretación de diversos fenómenos ambientales ocurridos en el humedal, en contraposición a lo que proporcionan registros temporales limitados.Peer Reviewe