Early R.,University of Evora |
Sax D.F.,Brown University
Ecology Letters | Year: 2011
Forecasts of species endangerment under climate change usually ignore the processes by which species ranges shift. By analysing the 'climate paths' that range shifts might follow, and two key range-shift processes - dispersal and population persistence - we show that short-term climatic and population characteristics have dramatic effects on range-shift forecasts. By employing this approach with 15 amphibian species in the western USA, we make unexpected predictions. First, inter-decadal variability in climate change can prevent range shifts by causing gaps in climate paths, even in the absence of geographic barriers. Second, the hitherto unappreciated trait of persistence during unfavourable climatic conditions is critical to species range shifts. Third, climatic fluctuations and low persistence could lead to endangerment even if the future potential range size is large. These considerations may render habitat corridors ineffectual for some species, and conservationists may need to consider managed relocation and augmentation of in situ populations. © 2011 Blackwell Publishing Ltd/CNRS.
Figueiredo J.,University of Evora
IEEE Transactions on Industrial Electronics | Year: 2011
This paper develops a new mathematical model, for pancake resolvers, that is dependent on a set of variables controlled by a resolver manufacturer-the winding parameters. This model allows a resolver manufacturer to manipulate certain in-process controllable variables in order to readjust already assembled resolvers that, without any action, would be scrapped for the production line. The developed model follows a two-step strategy where, on a first step, a traditional transformer's model computes the resolver nominal conditions and, on a second step, a linear model computes the corrections on the controllable variables, in order to compensate small deviations in design assumptions, caused by the variability of the manufacturing process. An experimental methodology for parameter identification is presented. The linearized model develops a complete new approach to simulate the product characteristics of a pancake resolver from the knowledge of manufacturer controllable variables (winding parameters). This model had been simulated and experimentally tested in a resolver manufacturing plant. The performed tests prove the efficiency of the developed model, stabilizing the product specifications in a dynamic environment with high variability of the production processes. All experiments had been led at the resolver manufacturer Tyco Electronic-Ésvora plant. © 2009 IEEE.
Agency: Cordis | Branch: H2020 | Program: IA | Phase: LCE-03-2014 | Award Amount: 17.79M | Year: 2015
Predictability and flexibility are key enablers to increase CSP penetration in the energy mix by a) increasing dispatchability b) making CSP less/not reliant on subsidies c) supporting stable grid operation d) enabling operators to access new revenue streams (electricity trading, ancillary services). Today CSP plants with molten salt storage only partly achieve these objectives. Key enabling technologies to be demonstrated and introduced in the market are 1) design and operation of molten salt once-through steam generator This will allow fully flexible plant operation; 2) design and implementation of integrated weather forecasting and dispatch optimization This will allow optimal management of the energy storage to maximize revenues while respecting constraints/commitments (e.g. to the grid). Towards 1), an innovative design approach is proposed, integrating process and equipment design with dynamic simulation of the system. Proven technologies in separate fields (molten salt ; once-through steam generator ; optimum control) will be for the first time integrated and demonstrated. Towards 2), different approaches to DNI forecasting (direct; mesoscale models) will be integrated to extend geographical coverage and improve reliability. Dispatch optimization under conditions of uncertainty (weather forecast) and perturbations (e.g. grid support requests) will be developed. Furthermore, automatic plant performance characterization by machine learning will be implemented to ensure a real optimum is achieved. For succesfull market introduction, a down-scale pilot will be realized. Here, integrated operation of once-through steam generator, weather forecast and dispatch optimization will be demonstrated. CSP will undergo large growth in developing markets, where grid constraints and market liberalization will play a role. Developint these key-enabling technologies will put european industries in the position to compete at the forefront in the market worldwide.
Agency: Cordis | Branch: H2020 | Program: RIA | Phase: SFS-19-2014 | Award Amount: 4.86M | Year: 2015
A good functioning of the European food system is key to deliver food and nutrition security for all Europeans. However, that system faces many economic, environmental and social challenges as well as opportunities following socio-economic and technological developments, that are not equally distributed throughout the EU. Future policymaking aiming at healthy and resilient systems needs to take into account this differentiation and diversity of approaches, which necessitate foresight activities that take into account both the development of important driving forces as well as the social and spatial diversity. Primary productionthat is agriculture, fisheries and aquacultureforms the foundation of the food system. Its structure and performance is influenced by various conditions shaped by both the public and the private sector. As economic agents, primary producers aim at generating a sufficient amount of income, but their financial conditions are highly dependent on public and private actors, such as government regulators (including the EUs agricultural and fisheries policies), the financial sector, suppliers, the food industry, retailers, etc. In other words, the web of policy requirements as well as input and output market imperfections greatly shape farmers and fishermens livelihoods. Knowledge on the conditions of primary producers and the driving forces influencing these conditions exists, but in a fragmented way: not all primary producers and regions are covered, not all driving forces have been investigated, cross-linkages between them have been insufficiently analysed, future opportunities are not well integrated, etc. The purpose of SUFISA is to identify sustainable practices and policies in the agricultural, fish and food sectors that support the sustainability of primary producers in a context of multi-dimensionsal policy requirements, market uncertainties and globalisation.
Miguel A.F.,University of Evora
Journal of Fluids and Structures | Year: 2010
Fluid flow in dendritic structures is approached based on hydrodynamics and a geometric description of the network. The hydrodynamic performance of the network, composed of series of rough ducts, is studied for both laminar and turbulent flow regimes. Transient response of internal fluid pressure is also modelled and analyzed. The oscillatory character of the internal pressure is linked with characteristics of the fluid and characteristics of the network. © 2009 Elsevier Ltd. All rights reserved.