Eines interactives per l'aprenentatge de la dinàmica i el control dels convertidors de potència

El projecte s'ha centrat en el disseny i desenvolupament de laboratoris virtuals per a la docència del dispositius i mètodes de gestió d’energia. Això s’ha realitzat a dos nivells clarament diferenciats, el primer grup de laboratoris correspon als convertidors electrònics de potencia i el segon grup de laboratoris correspon a un conjunt de casos d’aplicacions concretes. En el primer grup es descriu el detall del funcionament dels diferents elements mentre que en el segon els descriuen les idees i conceptes bàsics de funcionament. Els laboratoris virtuals de convertidors electrònics de potència inclouen el convertidor elevador (boost), el convertidor reductor (buck), i convertidors acobladors magnèticament. Aquestes permeten estudiar el comportament dinàmica des d’un punt de vista commutat o bé promitjat, les aplicacions incorporen també la possibilitat de sintonitzar els controladors. Aquestes aplicacions han estat desenvolupades per ser un complement per les sessions de pràctiques presencials. Els laboratoris virtuals d’aplicacions, inclouen els sistema de transport metropolità, el vehicle híbrid i els sistemes de gestió de talls transitoris en el subministrament d’energia principalment. Aquestes laboratoris permeten introduir els estudiants de forma qualitativa en els diferents conceptes i tècniques emprades en els sistemes de generació, transport i transformació d’energia. Totes les aplicacions han estat desenvolupades emprant Easy JAVA Simulations, aquesta eina permet desenvolupar laboratoris multiplataforma fàcilment distribuïbles a través d’internet.

La reducción de los costes de transporte en España (1800-1936)

This paper describes the improvement that took place in the Spanish transport system between 1800 and 1936. The text points out that, despite the investment efforts that were carried out between 1840 and 1855, the process of transport cost reduction only experienced substantial progress after 1855. The largest transport cost decrease of the period under consideration took place during the three decades between 1855 and the great depression of the late nineteenth century, through the substitution of the railroad for the traditional transport means in the main routes of the country, as well as through the gradual reduction of the price of railway transport. The process went on more slowly later on, thanks to the construction of additional raillway lines (until 1895) and the enlargement of the secondary road network. The process of transport cost reduction accelerated again from the 1920s onwards, thanks to the diffusion of the automobile technology.

Infraestructuras y desarrollo económico en el Pirineo Central (1850-2000)

This paper is aimed at describing the impact of infrastructure on the economic evolution of Central Pyrenees (i.e., Huesca and the Catalan"Alt Pirineu"). The text analyses if investment in railways, roads and dams favoured economic development or, on the contrary, was just an instrument to extract domestic resources. The paper distinguishes among three different periods. Firstly, during the second half of the nineteenth century and the first few years of the twentieth century, the lack of railway connections prevented the economic development of the area. Secondly, between the first decades of the twentieth century and 1975, a road network was set up that reinforced the economic decadence of the most depressed valleys, and the construction of large dams was a powerful factor of depopulation all over the region. Finally, from 1975 onwards, some trends may be observed towards the correction of the previous policies.

La integración del ferrocarril de alta velocidad en el medio urbano. El caso de Segovia-Guiomar

La llegada del tren de alta velocidad genera oportunidades de dinamización que deben de ser ante todo concretadas a escala local. Los lugares suelen reaccionar desplegando medidas de planificación y gestión para garantizar la mejor integración de la nueva infraestructura, procurar su coherencia con el modelo territorial y el mejor aprovechamiento de la accesibilidad que genera el nuevo tren. En este artículo se estudian las medidas desarrolladas en Segovia a raíz de la implantación del tren de alta velocidad con una estación localizada en la periferia, por lo que tuvieron que desplegarse un buen número de acciones de planificación territorial y gestión de la movilidad. A través del planeamiento municipal se trata de integrar la estación y su entorno al conjunto urbano, con el desarrollo de suelo urbanizable y nueva infraestructura viaria. La gestión de la movilidad pasa inicialmente por la articulación de la estación con el centro urbano a través de servicios de autobuses coordinados con los horarios de los trenes.

Cambio de hábitos y transformaciones territoriales en los corredores de alta velocidad ferroviaria. Resultados de una encuesta de viajeros en la línea Madrid-Barcelona

El tren de alta velocidad (TAV) está viviendo un auge importante en España. Ello implica una transformación territorial como resultado de una modificación del comportamiento de los viajeros debido a una mejora en el transporte ferroviario interurbano. En este contexto hay un elemento que ha obtenido una atención insuficiente. Se trata del acceso a la estación como parte fundamental del viaje puerta-a-puerta. Para hacer frente a la carencia de datos estadísticos sobre este aspecto, hemos realizado una encuesta a los viajeros de alta velocidad en la línea Madrid – Barcelona, que ayuda responder a la pregunta: ¿Cómo llega el viajero a la estación? Es imprescindible conocer este aspecto para planificar y realizar actuaciones de mejora intermodal adecuadas. Los resultados muestran que el acceso en vehículo privado es preponderante y que existe la necesidad de ofrecer más alternativas atractivas para acceder a las estaciones. Se concluye además que las estaciones centrales son preferibles, ya que generan una movilidad más sostenible.

Ciudad y ferrocarril en la España del siglo XXI. La integración de alta velocidad ferroviaria en el medio urbano

La reciente implantación y extensión de la red de alta velocidad ferroviaria en España está permitiendo relanzar un debate que en muchas ciudades no había sido resuelto de forma satisfactoria: la integración del ferrocarril en el medio urbano. En muchos casos, la llegada del nuevo tren se ha convertido en un instrumento urbanístico de primer orden, ya que conlleva una transformación de gran calado. En este artículo se realiza una lectura transversal, a través de las experiencias de diferentes ciudades españolas, para desarrollar una clasificación de las formas de integración de la alta velocidad ferroviaria y su impacto en la estructura urbana.

Using vegetation to characterize the avalanche to Canal del Roc Roig, Vall de Núria (Eastern Pyrenees, Spain)

Avalanche hazard maps of high accuracy are difficult to produce. For land-use planning and management purposes, a good knowledge of extreme run-out zones and frequencies of avalanches is required. In the present work, vegetation recognition (especially focused on Pinus uncinata trees) and dendrochronological techniques are used to characterize avalanches that have occurred in historical times, helping to determine both the extent of large or extreme avalanches and their occurrence in time. Vegetation was studied at the Canal del Roc Roig (eastern Pyrenees, Spain) avalanche path. The avalanches descending this path affect the railway that reaches the Vall de Núria resort and the run-up to the opposite slope. During winter 1996, two important avalanches affecting this path were well documented. These are compared with the results of the vegetation study, consisting of an inventory of flora, the recording of vegetation damages along eight transverse profiles at different altitudes on the path and a dendrochronological sampling campaign. The data obtained contributed to a characterization of the predominant snow accumulation in the starting zone, the 1996 avalanches and the range of frequencies of large avalanches. Also, traces of avalanches that increase the path mapped in the avalanche paths map published by the Institut Cartogràfic de Catalunya in 2000 were identified, improving the initial existing information.

Using vegetation to characterize the avalanche to Canal del Roc Roig, Vall de Núria (Eastern Pyrenees, Spain)

Avalanche hazard maps of high accuracy are difficult to produce. For land-use planning and management purposes, a good knowledge of extreme run-out zones and frequencies of avalanches is required. In the present work, vegetation recognition (especially focused on Pinus uncinata trees) and dendrochronological techniques are used to characterize avalanches that have occurred in historical times, helping to determine both the extent of large or extreme avalanches and their occurrence in time. Vegetation was studied at the Canal del Roc Roig (eastern Pyrenees, Spain) avalanche path. The avalanches descending this path affect the railway that reaches the Vall de Núria resort and the run-up to the opposite slope. During winter 1996, two important avalanches affecting this path were well documented. These are compared with the results of the vegetation study, consisting of an inventory of flora, the recording of vegetation damages along eight transverse profiles at different altitudes on the path and a dendrochronological sampling campaign. The data obtained contributed to a characterization of the predominant snow accumulation in the starting zone, the 1996 avalanches and the range of frequencies of large avalanches. Also, traces of avalanches that increase the path mapped in the avalanche paths map published by the Institut Cartogràfic de Catalunya in 2000 were identified, improving the initial existing information.

The Role of Railways in Export-Led Growth: The Case of Uruguay, 1870-1913

The social saving literature has highlighted the indispensable role that railways played before 1914 in several Latin American export-oriented economies, such as Mexico, Brazil and Argentina. The article analyses the case of Uruguay, a country that, by 1914, had built one of the densest railway networks in Latin America. The article shows that, in contrast to what happened in other economies of the region, the resource saving effects of the Uruguayan railways during the first globalisation were tiny due to the small share that railway output accounted for within the country's gross domestic product (GDP). Three complementary reasons are suggested to explain that result, namely: the geographical structure of the country; its sectoral specialisation; and the small scale of the Uruguayan economy. Due to these three characteristics, Uruguay was unable to benefit from railways in the way that other export-oriented Latin American economies did during the first period of globalisation. This conclusion draws attention to the geographic-specific character of railway technology.

Infrastructure and nation building: The regulation and financing of network transportation infrastructures in Spain (1720-2010)

This paper analyzes Spanish infrastructure policy since the early 1700s: Road building in the eighteenth century, railway creation and expansion in the nineteenth, motorway expansion in the twentieth, and high speed rail development in the twenty-first. The analysis reveals a long-term pattern, in which infrastructure policy in Spain has been driven not by the requirements of commerce and economic activity, but rather by the desire to centralize transportation around the country’s political capital.

The Spatial effects of transportation on industrial employment

This paper examines the direct and indirect impacts of transport infrastructure on industrial employment. We estimate regressions with spatial econometric methods using data from the Spanish regions for the period 1995-2008. We find that the density of motorways and the amount of port traffic (particularly general non-containerized and container traffic) are significant determinants of industrial employment in the region, while the effects of railway density and the amount of airport traffic are unclear. Our empirical analysis shows the existence of significant negative spatial spillovers for the density of motorways and levels of container port traffic while the impact of general non-containerized port traffic seems to be mainly local.