4 resultados para DISTURBANCES
em Universidad Politécnica de Madrid
Resumo:
The real and potential road influence on soundscape is considered a relevant management aspect that can assess the negative effects of massive visitants on such sensitive species -that have been living for centuries in the area-. As a first approach to the study of human disturbances sound impact, acoustic engineering tools allow us to model noise pollution caused by the main road that crosses the state ?Cabeza de Hierro? (M-604). For these preliminary results we use the French method XPS 31-133, recommend at EU level. Noise emission levels in black vulture nesting area are analyzed to understand the influence of human activities on rural areas and road management on biodiversity conservation. This approach develops a useful tool to make compatible the public enjoyment of forest services such as recreation or landscape scenary, the conservation of biodiversity as well as a suitable social and economic activity level ?timber and firewood harvesting, industry?- at the region.
Resumo:
This contribution presents results of an incompressible two-dimensional flow over an open cavity of fixed aspect ratio (length/depth) L/D = 2 and the coupling between the three dimensional low frequency oscillation mode confined in the cavity and the wave-like disturbances evolving on the downstream wall of the cavity in the form of Tollmien-Schlichting waves. BiGlobal instability analysis is conducted to search the global disturbances superimposed upon a two-dimensional steady basic flow. The base solution is computed by the integration of the laminar Navier-Stokes equations in primitive variable formulation, while the eigenvalue problem (EVP) derived from the discretization of the linearized equations of motion in the BiGlobal framework is solved using an iterative procedure. The formulation of the BiGlobal EVP for the unbounded flow in the open cavity problem introduces additional difficulties regarding the flow-through boundaries. Local analysis has been utilized for the determination of the proper boundary conditions in the upper limit of the downstream region
Resumo:
Disturbances shape forest ecosystems by influencing their composition, structure, and processes. In the Mediterranean Basin, changes in the disturbance regimes have been predicted to occur in the next future with a higher occurrence of extreme events of drought, wildfire, and – to a lesser extent – windstorm. Woody species are the main elements defining the structure and functioning of forest ecosystems. Recently, response-type diversity has been pointed out as an appropriate indicator of ecosystems resilience. For this, we have elaborated a complete response-trait database for the tree and shrubby species considered in the Third Spanish National Forest Inventory (3SNFI). In the database, the presence or absence of nine response traits associated to drought, fire, and wind were assigned to each species. The database reflected the lack of information about some important traits (in particular for shrubby species) and allowed to determine those traits most widely distributed. The information contained in the database was then used to assess a relative index of forest resilience to these disturbances calculated from the abundance of response traits and the species redundancy for each plot of the 3SNFI; considering both tree and shrubby species. In general, few plots showed high values of the resilience index, probably because some traits were scarcely presented in the species and also because most plots presented very few species. The cartographic representation of the index showed low values for the stands located in mountainous ranges, which are mostly composed by species typical from central Europe. In the other side, Eucalyptus plantations in Galicia appeared as one thee the most resilient ecosystems, due to its higher adaptive capacity to persist after the occurrence of drought, fire, and windstorm events. We conclude that the response traits database can constitute a useful tool for forest management and planning and for future research to enhance the forest resilience.
Resumo:
The search for new energy models arises as a necessity to have a sustainable power supply. The inclusion of distributed generation sources (DG) allows to reduce the cost of facilities, increase the security of the grid or alleviate problems of congestion through the redistribution of power flows. In remote microgrids it is needed in a particular way a safe and reliable supply, which can cover the demand for a low cost; due to this, distributed generation is an alternative that is being widely introduced in these grids. But the remote microgrids are especially weak grids because of their small size, low voltage level, reduced network mesh and distribution lines with a high ratio R/X. This ratio affects the coupling between grid voltages and phase shifts, and stability becomes an issue of greater importance than in interconnected systems. To ensure the appropriate behavior of generation sources inserted in remote microgrids -and, in general, any electrical equipment-, it is essential to have devices for testing and certification. These devices must, not only faithfully reproduce disturbances occurring in remote microgrids, but also to behave against the equipment under test (EUT) as a real weak grid. This also makes the device commercially competitive. To meet these objectives and based on the aforementioned, it has been designed, built and tested a voltage disturbances generator, in order to provide a simple, versatile, full and easily scalable device to manufacturers and laboratories in the sector.