Search

Resumen: El fenómeno de fatiga como unos de los principales mecanismos de deterioro de las capas asfálticas. El ensayo de fatiga a flexión a cuatro puntos de apoyo es uno de los procedimientos más utilizados para determinar la resistencia a la fatiga de las mezclas asfálticas. Existen, a nivel internacional, diversas normas que estandarizan este tipo de ensayo, las cuales se diferencian básicamente por la forma de la onda de carga aplicada y por el criterio de rotura utilizado. Este artículo tiene como objetivo presentar los resultados de la influencia del tipo de onda de carga utilizada, haversine o sinusoidal, en la resistencia a la fatiga de una mezcla asfáltica, como también, la influencia de los modelos de fatiga obtenidos en la previsión de la rotura por fatiga de la capa asfáltica en una estructura de un pavimento flexible. Al final, se concluyó que la vida útil de la capa asfáltica estimada utilizando los modelos obtenidos en el ensayo con ondas con forma haversine fue 67 veces mayor que cuando estimada con los modelos de los ensayos realizados con carga sinusoidal. Abstract: The phenomenon of fatigue can be considered as one of the main causes of the asphalt Surface course failure. The Four-Point Bending Apparatus is the widespread equipment used to determine the fatigue resistance of asphalt mixtures. Worldwide there are several standard procedures that rule this test. The main difference between them remains in the waveform, in wich the load is applied, and in the failure criteria. This paper reports the influence from the waveform, haversine orsinusoidal, on the fatigue resistance of an asphalt mixture. In adition, through numerical simulation, it was evaluated ones found on sinusoidal tests.

International audience; Medicanes are cyclones over the Mediterranean Sea having a tropical structure and a rather small size, for which the sea-atmosphere interaction plays a fundamental role. High resolution and ocean-atmosphere coupled RCM simulations performed in MedCORDEX and EURO-CORDEX projects are used to analyze the ability of RCMs to represent the observed characteristics of medicanes, and the impact of increasing resolution and using air-sea coupling on its simulation. An observational database based on satellite images combined with very high resolution simulations (Miglietta et al. 2013) is used as the reference for evaluating the simulations. The simulated medicanes do not coincide in general with the observed cases, so that the evaluation should be done in a statistical sense. The spatial distribution of medicanes is generally well simulated, while the monthly distribution reveals the difficulty of simulating the first medicanes appearing in September after the summer minimum. Large differences are found among models, supporting the use of multi-model ensembles. Interesting trade-offs are found for some models, as better values for intensity are associated to worse frequency values in one model, or relatively good values of frequency and intensity are obtained at the expense of a damped air-sea interaction in a model with spectral nudging. High resolution has a strong and positive impact on the frequency of simulated medicanes, while the effect on its intensity is less clear. Air-sea coupling reduces the medicane frequency, as could be expected due to a negative intensity feedback that is known for tropical cyclones. A preliminary analysis indicates that this feedback could depend on the oceanic mixed layer depth, increasing the interest of applying ocean-atmosphere coupled RCMs

The Mediterranean is expected to be one of the most prominent and vulnerable climate change "hotspots" of the twenty-first century, and the physical mechanisms underlying this finding are still not clear. Furthermore, complex interactions and feedbacks involving ocean-atmosphere-land-biogeochemical processes play a prominent role in modulating the climate and environment of the Mediterranean region on a range of spatial and temporal scales. Therefore, it is critical to provide robust climate change information for use in vulnerability-impact-adaptation assessment studies considering the Mediterranean as a fully coupled environmental system. The Mediterranean Coordinated Regional Downscaling Experiment (Med-CORDEX) initiative aims at coordinating the Mediterranean climate modeling community toward the development of fully coupled regional climate simulations, improving all relevant components of the system from atmosphere and ocean dynamics to land surface, hydrology, and biogeochemical processes. The primary goals of Med-CORDEX are to improve understanding of past climate variability and trends and to provide more accurate and reliable future projections, assessing in a quantitative and robust way the added value of using high-resolution and coupled regional climate models. The coordination activities and the scientific outcomes of Med-CORDEX can produce an important framework to foster the development of regional Earth system models in several key regions worldwide. ©2016 American Meteorological Society.

Wind energy is susceptible to global climate change because it could alter the wind patterns. Then, improvement of our knowledge of wind field variability is crucial to optimize the use of wind resources in a given region. Here, we quantify the effects of climate change on the surface wind speed field over the Iberian Peninsula and Balearic Islands using an ensemble of four regional climate models driven by a global climate model. Regions of the Iberian Peninsula with coherent temporal variability in wind speed in each of the models are identified and analysed using cluster analysis. These regions are continuous in each model and exhibit a high degree of overlap across the models. The models forced by the European Reanalysis Interim (ERA-Interim) reanalysis are validated against the European Climate Assessment and Dataset wind. We find that regional models are able to simulate with reasonable skill the spatial distribution of wind speed at 10 m in the Iberian Peninsula, identifying areas with common wind variability. Under the Special Report on Emissions Scenarios (SRES) A1B climate change scenario, the wind speed in the identified regions for 2031-2050 is up to 5% less than during the 1980-1999 control period for all models. The models also agree on the time evolution of spatially averaged wind speed in each region, showing a negative trend for all of them. These tendencies depend on the region and are significant at p = 5% or slightly more for annual trends, while seasonal trends are not significant in most of the regions and seasons.