Vibrations of Short Span Railway Bridges for High Speed Lines

The physical model based on moving constant loads is widely used for the analysis of railway bridges. Nevertheless, this model is not well-suited for the study of short span bridges (L<=15-20 m), and the results it produces (displacements and accelerations) are much greater than those obtained experimentally. In this paper two factors are analysed which are believed to have an influence in the dynamic behaviour of short bridges. These two factors are not accounted for by the moving loads model and are the following: the distribution of the loads due to the presence of the sleepers and ballast layer, and the train-bridge interaction. Several numerical simulations have been performed in order to decide on their influence, and the results are presented and discussed herein.

Una asignatura on-line de Historia de los Algoritmos

This paper describes the objectives, contents learning methodology and results of an on-line course about History of Algorithms for engineering students of the Polytechnic University of Madrid. This course is conducted in a virtual environment based on Moodle, with an educational model centered at student which includes a detailed planning of learning activities. . Our experience indicates that this subject is is highly motivating for students and the virtual environment facilitates competencies development.

Influence of the Second Bending Mode on the Response of High-Speed Bridges at Resonance

This paper deals with the assessment of the contribution of the second bending mode to the dynamic behavior of simply supported railway bridges. Traditionally the contributions of modes higher than the fundamental have been considered of little importance for the computation of the magnitudes of interest to structural engineers (vertical deflections, bending moments, etc.). Starting from the dimensionless equations of motion of a simply supported beam subjected to moving loads, the key parameters governing the dynamic behavior are identified. Then, a parametric study over realistic ranges of values of those parameters is conducted, and the influence of the second mode examined in detail. The main purpose is to decide whether the second mode should be taken into account for the determination of the maximum displacement and acceleration in high-speed bridges. In addition, the reasons that cause the contribution of the second bending mode to be relevant in some situations are highlighted, particularly with regard to the computation of the maximum acceleration.

Extension of Euskalduna Conference Centre and Concert Hall: A Contemporary Application of Irregular Reciprocal Frames

Reciprocal frame structures, formed by a set of self-supported elements in a closed circuit, have long been used since antiquity to cover large spans with small elements. The roof structure of the Euskalduna conference centre and concert hall extension in Bilbao, covering an irregu- lar geometry of 3000 m2 with a maximum span of 45 m, presented an interesting opportunity to revisit the concept and to apply these classical systems. Furthermore, its analysis and develop- ment led to an interesting discussion on reciprocal frames. They showed great sensitivity of these systems to the local modification of a particular element, establishment of irregular load paths, mobilisation of almost the entire sys- tem when locally applying a punctual load and, finally, its large deformability. Besides, reciprocal frames present particular construction complexities and possibilities due to the moderate length of the structural elements, the predominance of shear-only connec- tions and the necessity of the entire system to be completely erected to guarantee its stability. Euskalduna extension, completed in 2012, is one of the largest and a very par- ticular case of irregular reciprocal frame structures built in the world. It shows the formal possibilities and potentiality of reciprocal frames to respond to free and irregular geometries.

An Online Course on the History of Algorithms.

This paper describes the objectives, content, learning methodology and results of an online course on the History of Algorithms for engineering students at Polytechnic University of Madrid (UPM). This course is conducted in a virtual environment based on Moodle, with a student-centred educational model which includes a detailed planning of learning activities. Our experience indicates that this subject is highly motivating for students and the virtual environment facilitates competencies development

DERIVE and Linear Algebra

This work describes an experience with a methodology for learning based on competences in Linear Algebra for engineering students. The experience has been based in autonomous team work of students. DERIVE tutorials for Linear Algebra topics are provided to the students. They have to work with the tutorials as their homework. After, worksheets with exercises have been prepared to be solved by the students organized in teams, using DERIVE function previously defined in the tutorials. The students send to the instructor the solution of the proposed exercises and they fill a survey with their impressions about the following items: ease of use of the files, usefulness of the tutorials for understanding the mathematical topics and the time spent in the experience. As a final work, we have designed an activity directed to the interested students. They have to prepare a project, related with a real problem in Science and Engineering. The students are free to choose the topic and to develop it but they have to use DERIVE in the solution. Obviously they are guided by the instructor. Some examples of activities related with Orthogonal Transformations will be presented.

Aplicación de algoritmos paramétricos de generación formal en el diseño estructural. La Ópera de Sídney desde una perspectiva contemporánea.

El importante desarrollo tecnológico e industrial surgido especialmente durante la segunda mitad del siglo pasado ha eliminado las históricas limitaciones técnicas en el ámbito de los pro-­? yectos arquitectónicos, desembocando en la situación actual en la que cualquier planteamiento formal puede ser analizado desde un punto de vista estructural, concluyéndose por tanto que ha desaparecido la barrera del análisis en lo que al desarrollo de un proyecto arquitectónico se refiere. En la actualidad, al igual que a finales del siglo XIX, nos encontramos en un periodo de transi-­? ción, y también, como entonces, es la tecnología la que orienta el cambio. No la tecnología de los nuevos materiales (hormigón y acero) como sucedía tras la revolución industrial sino que es la nueva tecnología digital aplicada a los sistemas de diseño, cálculo y fabricación la que están siendo el motor de la actual transformación. Hoy no es tanto el paradigma mecanicista el que prevalece en muchos casos en la concepción de los edificios sino que, nuevos elementos como la tecnología digital integrada está cambiando la forma de diseñar y concebir el entorno cons-­? truido. Ante este contexto cabría plantearse las siguientes cuestiones: ¿Puede el diseño paramétrico y la tecnología CAD-­?CAM-­?CAE en conjunción con los programas actuales de análisis estructural basados en el Método de los Elementos Finitos hacer más sencilla la construcción de estructu-­? ras ligeras y eficientes hoy en día? ¿Puede la tecnología digital ayudar a ampliar el abanico for-­? mal a la hora de diseñar edificios y a la vez permitir el uso de sistemas estructurales racionales que optimicen el consumo de materiales bajo dichas circunstancias?

Análisis de los aspectos intrínsecos y extrínsecos de la coherencia en los textos para la enseñanza del inglés académico y profesional

RESUMEN. En este artículo abordamos la evaluación de textos especializados, con fines docentes, mediante un estudio experimental basado en los rasgos de textualidad que hacen que el texto resulte coherente para sus lectores. Se comprueba, empíricamente, que existe una correlación positiva entre la adecuación del texto a los rasgos de textualidad y su comprensión por parte de los alumnos de ingeniería de Minas que han formado el grupo experimental. Queda patente cómo textos que en un primer análisis se pudiera afirmar que cumplen los criterios de textualidad, aplicados a otro contexto situacional distinto de aquel para el que fueron escritos, pueden no cumplir con los mismos criterios, resultando inadecuados o no totalmente inteligibles. Se constata que la coherencia textual no depende exclusivamente de factores intratextuales, sino también de aquellos otros extratextuales relacionados con la comunidad receptora. ABSTRACT. This article deals with the evaluation of specialised texts for eduactional purposes. It reports on an experimental study based on those textuality feactures which make a text coherent to the readers. It is empirically tested that there exists a positive correlation between textuality features of a given text and its reading comprehension by engineering students participating in the experimental study. It is shown how texts, that initially comply with textuality features, taken into a different context from that for which they were written, may become inadequate or even non understandable. It becomes evident that textual coherence does not depend exclusively on intratextual elements but on those extratextual ones related to the receiving community as well.

Exploring cognition processes in second language acquisition: the case of cognates and false-friends in EST

This article explores one aspect of the processing perspective in L2 learning in an EST context: the processing of new content words, in English, of the type ‘cognates’ and ‘false friends’, by Spanish speaking engineering students. The paper does not try to offer a comprehensive overview of language acquisition mechanisms, but rather it is intended to review more narrowly how our conceptual systems, governed by intricately linked networks of neural connections in the brain, make language development possible, creating, at the same time, some L2 processing problems. The case of ‘cognates and false friends’ in specialised contexts is brought here to illustrate some of the processing problems that the L2 learner has to confront, and how mappings in the visual, phonological and semantic (conceptual) brain structures function in second language processing of new vocabulary. Resumen Este artículo pretende reflexionar sobre un aspecto de la perspectiva del procesamiento de segundas lenguas (L2) en el contexto del ICT: el procesamiento de palabras nuevas, en inglés, conocidas como “cognados” y “falsos amigos”, por parte de estudiantes de ingeniería españoles. No se pretende ofrecer una visión completa de los mecanismos de adquisición del lenguaje, más bien se intenta mostrar cómo nuestro sistema conceptual, gobernado por una complicada red de conexiones neuronales en el cerebro, hace posible el desarrollo del lenguaje, aunque ello conlleve ciertas dificultades en el procesamiento de segundas lenguas. El caso de los “cognados” y los “falsos amigos”, en los lenguajes de especialidad, se trae para ilustrar algunos de los problemas de procesamiento que el estudiante de una lengua extranjera tiene que afrontar y el funcionamiento de las correspondencias entre las estructuras visuales, fonológicas y semánticas (conceptuales) del cerebro en el procesamiento de nuevo vocabulario.

Estrategias metacognitivas y metalingüísticas empleadas en la redacción de los informes técnicos

Este trabajo presenta un análisis de las estrategias cognitivas, metacognitivas y metalingüísticas implicadas en la elaboración de los informes técnicos en las asignaturas de IPA, para alumnos de ciencias e ingenierías. Las aplicaciones didácticas se formulan en relación con los niveles comunicativos del Marco de Referencia Europeo para las lenguas, teniendo en cuenta uno de los géneros lingüísticos más frecuentes dentro de los ámbitos de la ciencia y la técnica.. ABSTRACT. This paper presents an analysis of cognitive, metacognitive and metalinguistic strategies implied in the written production of technical reports, as they may be considered in academic writing courses for science and engineering students. Methodological applications are made bearing in mind the European Framework of Reference for Languages in relation to one of the most frequent genres produced by scientists and engineers..

New Courthouse at El Ejido

The courthouse at El Ejido has a trapezoid floor plan (47 m × 55/26 m) and comprises two distinct volumes that are structurally connected at the basement level and by the footbridges on the upper storeys. A third trapezoid unit featuring a glazed curtain wall facade cantilevers 8 m off the main facade of the front volume. This facade is a structural diaphragm wall, constituted by nine rows of vertical precast concrete members separated by horizontal cast-in-place, self-compacting concrete chords. The location of the courthouse in a seismic area and the small number of horizontal supports for the facade make this wall potentially vulnerable. The high risk, in particular, during construction required careful planning based on a detailed analysis of the interaction between the structure and the ancillary resources used to build it

La competencia lingüística en el uso de los grupos nominales en inglés académico y profesional y su didáctica: estudio empírico

Esta tesis doctoral consiste en un estudio empírico de la competencia lingüística del alumnado de la Escuela Técnica Superior de Ingenieros Industriales (ETSII), de la Universidad Politécnica de Madrid (UPM) en el uso de los grupos nominales (GN) en inglés profesional y académico (IPA). Mediante el análisis estadístico de los datos de las pruebas de nivel de inglés general y de conocimiento de los rasgos lingüísticos diferenciadores del IPA, se ha buscado constatar que los GN, tan presentes en los textos ingleses de carácter científico-técnico, son uno de los rasgos IPA que más dificultad presenta para el alumnado de ingeniería de habla española, cuya enseñanza es necesario abordar de forma diferenciada para que se puedan usar correctamente. El trabajo comienza presentando las características lingüísticas generales del IPA, entre las que destaca la frecuente presencia de los GN en las comunicaciones de carácter científico y técnico. Comprueba la hipótesis de que la comprensión y el uso de los GN es el rasgo lingüístico que ofrece mayor dificultad para esta población. Se detiene en explicar las propiedades de los GN en inglés y de las palabras que lo forman; es decir, muestra clases de palabras, regularidades y excepciones que están presentes en los textos científico-técnicos. También expone y razona el comportamiento de las distintas categorías gramaticales que pueden figurar como premodificadoras y se centra en ejemplos reales y datos objetivos, para llegar a conclusiones cuantitativas sobre el uso y la frecuencia de los GN en el discurso científico-técnico, así como en los diferentes grados de dificultad que dichas construcciones presentan al alumnado. El método de investigación seguido consiste en la recopilación y análisis estadístico de los datos procedentes de una muestra de población de alumnos de 5º curso de la ETSII de la UPM utilizando el análisis de la varianza ANOVA. Los datos se han tratado teniendo en cuenta el nivel general de inglés de cada alumno, según el Marco Común Europeo de Referencia para las Lenguas (MCERL), que oscila entre el nivel A2 y el C1, con una mayor frecuencia de B1 y B2. Las conclusiones se basan en el análisis de los datos empíricos obtenidos, que nos permiten deducir unos principios generales relevantes respecto al uso de los GN –simples y complejos- en el inglés para la ciencia y la tecnología (ICT) y al grado de dificultad que sus distintos tipos presentan al alumnado, con un grado de confianza superior al 95%. A partir de estos datos se ofrece un planteamiento didáctico que facilite la comprensión y elaboración de los distintos tipos de GN. La estructura general de la tesis se divide en seis capítulos. El capítulo 1 es una introducción en la que se presentan las razones que han motivado esta tesis, las hipótesis, los objetivos y la metodología de la misma. En el capítulo 2 se recogen los rasgos lingüísticos distintivos del ICT, incidiendo en la relación competencia comunicativa/competencia lingüística. En el capítulo 3 se analizan los GN profundizando en aspectos lingüísticos. El capítulo 4 se centra en el estudio empírico propiamente dicho y en el análisis estadístico de los datos. Del análisis se extraen las conclusiones objetivas sobre la dificultad que presentan los diferentes rasgos IPA analizados, con detenimiento en los GN simples y complejos. El capítulo 5 ofrece un planteamiento didáctico práctico sobre la enseñanza de los GN en el contexto del ICT, con una investigación sobre el terreno y el análisis estadístico de los resultados obtenidos antes y después de la aplicación didáctica. En el capítulo 6 se comentan los resultados obtenidos a lo largo del estudio, aportando las conclusiones, las limitaciones y las recomendaciones para futuros trabajos de investigación sobre el tema de la tesis. ABSTRACT This doctoral thesis consists of an empirical study of the linguistic competence of the Technical University of Madrid (UPM) industrial engineering students on the use of nominal groups (NG) in English for Academic and Professional Purposes (EAPP). In order to confirm that NG is the EAPP linguistic feature that presents the greatest difficulty to Spanish engineering students, a statistical analysis of the data obtained from the application of a general English test and the EAPP linguistic features tests -developed for this purpose- was carried out. Consequently, this linguistic feature needs to be specifically taught in order to be used correctly by Spanish engineering students. The study begins by presenting the general language characteristics of EAPP, among which the frequent presence of NG in scientific and technical writings stands out. It verifies the hypothesis that the understanding and use of NG in English is the most difficult linguistic feature for Spanish engineering students. It explains the features of English NG analyzing the words they are composed of by depicting the types of words, regularities and exceptions that are present in technical and scientific English. It also explains the behavior of the different grammar categories that act as pre-modifiers of the noun and focuses on real examples taken from authentic publications and quantitative data, to reach objective conclusions about the use and degree of difficulty of the NG for the students. The research methodology includes the gathering of data from the 5th year industrial engineering students´ tests and analyzing them by means of the ANOVA statistical application. The data have been treated in relation to the students’ Common European Framework of Reference for Languages (CEFRL) levels, which range from A2 to C1, although the majority lye between B1 and B2 levels. The conclusions are based on the results, which allow us to obtain relevant information about the understanding and use of NG –simple and complex- by the focus group, with a 95% confidence level. From these data, a methodological approach to NG teaching has been tested to help students to acquire such linguistic feature. The general structure of this thesis is divided into six chapters. The first is an introduction containing the reasons that have motivated this piece of research, the hypotheses, objectives and methodology employed. The second deals with the distinctive linguistic features of EST underlying the concepts of linguistic and communicative competence. Chapter three focuses on the grammar aspects of NG. Chapter four contains the empirical study and the statistical analysis of the data. Results allow us to reach objective conclusions about the degree of difficulty of the EAPP linguistic features studied, focusing on simple and complex NG. Chapter five discusses a methodological approach to the teaching of NG in an EST context, comparing students’ test results before and after the NG teaching application. Finally, chapter six discusses the findings obtained along the study, presenting the conclusions, limitations and recommendations for future research in this area.

Finite element code-based modeling of a multi-feature isolation system and passive alleviation of possible inner pounding

The existing seismic isolation systems are based on well-known and accepted physical principles, but they are still having some functional drawbacks. As an attempt of improvement, the Roll-N-Cage (RNC) isolator has been recently proposed. It is designed to achieve a balance in controlling isolator displacement demands and structural accelerations. It provides in a single unit all the necessary functions of vertical rigid support, horizontal flexibility with enhanced stability, resistance to low service loads and minor vibration, and hysteretic energy dissipation characteristics. It is characterized by two unique features that are a self-braking (buffer) and a self-recentering mechanism. This paper presents an advanced representation of the main and unique features of the RNC isolator using an available finite element code called SAP2000. The validity of the obtained SAP2000 model is then checked using experimental, numerical and analytical results. Then, the paper investigates the merits and demerits of activating the built-in buffer mechanism on both structural pounding mitigation and isolation efficiency. The paper addresses the problem of passive alleviation of possible inner pounding within the RNC isolator, which may arise due to the activation of its self-braking mechanism under sever excitations such as near-fault earthquakes. The results show that the obtained finite element code-based model can closely match and accurately predict the overall behavior of the RNC isolator with effectively small errors. Moreover, the inherent buffer mechanism of the RNC isolator could mitigate or even eliminate direct structure-tostructure pounding under severe excitation considering limited septation gaps between adjacent structures. In addition, the increase of inherent hysteretic damping of the RNC isolator can efficiently limit its peak displacement together with the severity of the possibly developed inner pounding and, therefore, alleviate or even eliminate the possibly arising negative effects of the buffer mechanism on the overall RNC-isolated structural responses.

On the Insurmountable Size of Truss-like Structures

Galileo postulated the existence of an insurmountable size for stone columns bearing a useful load as the size for which the structure is only able to resist its self-weight. Herein a method for the determination of the unsurmountable size for truss-like structures is shown, given the form of these structures and the ratio between the allowable stress and the specific weight of the material (the material structural scope). Three types of bars are considered: straight bars, with solid and hollow rectangular cross-section, and catenary bars with circular cross-section —a limit and theoretical case for estimating a meaningful upper bound of the structural scope—. An approximate rule to estimate the structural efficiency —here named GA rule— is shown, and is compared with numerical solutions using the proposed method.

Diseño y construcción de una mini-turbina eólica

Dado que es difícil imaginar en el futuro una sociedad moderna donde la energía no juegue un papel fundamental y puesto que numerosos estudios han demostrado que el ritmo actual de consumo de combustibles es insostenible y perjudicial para la vida del planeta, es fundamental concienciar a la humanidad de que un cambio de tendencia no solo es necesario sino que es imperativo. No se trata de erradicar por completo el uso de fuentes de carácter fósil, pues en muchos países es su principal o incluso su única forma de obtener energía, sino de avanzar hacia un equilibrio en la generación, para lo que será vital permitir el desarrollo de energías limpias, aumentar la eficiencia de la tecnología y reducir el consumo. En este contexto se ha decidido construir un rotor eólico de pequeñas dimensiones que servirá como herramienta de estudio para alumnos de ingeniería. Para diseñar la turbina se ha desarrollado un modelo de programación informática que, basado en conceptos aerodinámicos, permite calcular la geometría de las palas en función de unas condiciones iniciales, estimar la potencia del rotor y obtener sus curvas de funcionamiento. Uno de los principales problemas de la tecnología eólica es su alta variabilidad, por ello se ha implementado un sistema de regulación de velocidad; se trata de un mecanismo que actúa sobre la orientación de las palas y permite regular la potencia de un generador eléctrico acoplado al rotor. Los aerogeneradores actuales recurren a este tipo de sistemas para tratar de suavizar los desequilibrios de potencia que puedan producir las ráfagas de viento. Se ha recurrido a un software de diseño asistido por ordenador para dibujar tanto el rotor como el sistema de regulación de velocidad. La mayoría de las piezas del rotor se han fabricado con ayuda de una impresora 3D, otras, las metálicas, se han tallado en aluminio mediante un torno. Aunque el programa informático que realiza los cálculos aerodinámicos devuelve datos teóricos a cerca del comportamiento del rotor, se ha creído necesario probar el molino mediante ensayos de laboratorio a fin de obtener un resultado más realista.Abstract Given that it’s difficult to imagine any modern society in the future where energy does not play a crucial role, and as many studies have shown that the actual rate of fuel consumption is unsustainable and harmful to life on the planet, it is essential to raise mankind’s awareness that a change in the current trend is not only necessary, but is also imperative. It is not a question of completely eradicating the use of fossil fuels, as in many countries they are the main or even the only way of generating energy, but rather working towards a balance in generation. To do so it is vital to encourage the development of clean energies, increase technological efficiency and reduce consumption. In view of this we have decided to build a small scale wind turbine rotor which can be used as a study tool for engineering students. To design the turbine a software programme was developed based on aerodynamic concepts, which allows us to calculate the geometry of the blades depending on certain initial conditions, estimate the power of the turbine, and obtain performance curves. One of the main issues with wind technology is its high variability, and therefore we implemented a speed regulation system consisting of a mechanism that varies the orientation of the blades and thus allows us to regulate the power of an electric generator attached to the turbine. Current wind powered generators use this type of system to try to smooth out spikes in power that may be caused by gusts of wind. We have used CAD software to design both the turbine itself and the speed regulation system. Most of the turbine parts have been manufactured with the aid of a 3D printer, while the other metallic parts have been turned on made a lathe in aluminum. Although the software programme which calculates the aerodynamics provide us theoretical data about the operation of the rotor. We consider it necessary to test the wind turbine in a lab to obtain more accurate results.