Special section Modeling Transport (Energy) Demand and Policies.-- 14 pages, 2 figures, 2 tables, 6 appendixA global alternative mix to fossil fuels is proposed, based on proven renewable energy technologies that do not use scarce materials. The mix consists of a combination of onshore and offshore wind turbines, concentrating solar power stations, hydroelectricity and wave power devices attached to the offshore turbines. Solar photovoltaic power could contribute to the mix if its dependence on scarce materials is solved. The most adequate deployment areas for the power stations are studied, as well as the required space. Material requirements are studied for the generation, power transport and for some future transport systems. The order of magnitude of copper, aluminium, neodymium, lithium, nickel, zinc and platinum that may be required for the proposed solution is obtained and compared with available reserves. Overall, the proposed global alternative to fossil fuels seems technically feasible. However, lithium, nickel and platinum could become limiting materials for future vehicles fleet if no global recycling systems were implemented and rechargeable zinc-air batteries would not be developed; 60% of the current copper reserves would have to be employed in the implementation of the proposed solution. Altogether, they may become a long-term physical constraint, preventing the continuation of the usual exponential growth of energy consumption. © 2011 Elsevier LtdPeer Reviewe

8 pages, 9 figures, 1 table, 1 appendix.-- Full-text version available Open Access at: http://www.icm.csic.es/files/oce/almacen/papers/AR-2008-29.pdfImages from an Argus beach monitoring station were analyzed to count the number of people on two city beaches in Barcelona (NW Mediterranean) every hour for 4 years. Daily, weekly, seasonal, and interannual user distribution patterns were clearly established. Two different fit models were applied to the data based on a Fourier polynomial and nonlinear criteria, including external factors such as temperature and wind conditions, as well as predisposition factors. Finally, the evolution of beach users was compared with morphological beach changes caused by natural processes and human action. The results demonstrated that video observations provide a suitable method for counting people on the beach that could be useful for a number of coastal management applications.This work was funded by the Spanish Ministry of Science and Technology within the project PUDEM (REN2003-06637-C02). E. Ojeda is supported by a University Professors Formation grant from the Spanish Ministry of Education and Science.Peer reviewe

The instability growth leading to a liquid sheet breakup has been studied with the objective of improving the understanding of the fundamental mechanisms of atomization. A three-dimensional Lagrangian code based on vortex dynamics methods has been implemented to track the air/liquid interfaces treated as inviscid vortex sheets. The results of these numerical simulations indicate a possible explanation for the presence of transverse and longitudinal filaments observed in liquid sheet air-assisted atomization experiments.

Europe must move towards a 100% renewable transportation system for climate, energy and sustainability reasons. We estimate the capital and energy required for building and operating a renewable transportation system providing similar services as the EU-28 transport system of 2016. It could be based on: biogas or fuel cell vessels; liquid biogas powered aircrafts; electric railways and fuel cell or electric vehicles between major cities; and car sharing, electric buses and electric two- and three-wheelers, for short journeys. A system of charging posts on the streets and roads for passenger and commercial e-vehicles is studied. Alternatively, a Tracked Electric Vehicle system of continuous power on European roads would improve energy efficiency and the saving of scarce metals (Ni, Li), at a lower cost, if only national roads were electrified. The investment for the construction of the whole system would be 2.3–2.7% of the EU’s GDP per year for 30 years. The new system operation would require 16% less energy than that of 2016, with reduction of 70% in road transport. However, shipping and aviation would demand 162% and 149% more energy, respectively, if liquefied biogas were used as fuel. A type of land transport fully based on trains would provide a similar service to that of an electric vehicle fleet, with a 29% lower energy consumption.