Acercamiento a la Cooperación Descentralizada desde un estudio de caso: la Diputación de Palencia

El TFM que aquí se presenta analiza una de las modalidades más significativas de la Cooperación al Desarrollo española: la Cooperación Descentralizada. Esto lo hacemos mediante un estudio de caso de una corporación local: la Diputación de Palencia. El trabajo aborda, por un lado, una aproximación teórica y conceptual de la Cooperación Descentralizada, tratando sus orígenes, evolución, características y elementos clave. En segundo lugar, se realiza un estudio de caso centrado en la Diputación de Palencia; este estudio permite reflexionar sobre las potencialidades y los límites de esta modalidad, analizando el contexto autonómico, la trayectoria de la cooperación de la entidad, los instrumentos empleados, los sistemas de puntuación, la coordinación de agentes de desarrollo, etc. A modo de resumen se sintetizan los alcances, límites y retos de su trayectoria para acabar con unas breves conclusiones.Departamento de Sociología y Trabajo SocialMáster en Cooperación Internacional para el Desarroll

On the development of a parametric aerodynamic model of a stratospheric airship

[EN] The idea of self-sustaining air vehicles that excited engineers in the seventies has nowadays become a reality as proved by several initiatives worldwide. High altitude platforms, or Pseudo-satellites (HAPS), are unmanned vehicles that take advantage of weak stratospheric winds and solar energy to operate without interfering with current commercial aviation and with enough endurance to provide long-term services as satellites do. Target applications are communications, Earth observation, positioning and science among others. This paper reviews the major characteristics of stratospheric flight, where airplanes and airships will compete for best performance. The careful analysis of involved technologies and their trends allow budget models to shed light on the capabilities and limitations of each solution. Aerodynamics and aerostatics, structures and materials, propulsion, energy management, thermal control, flight management and ground infrastructures are the critical elements revisited to assess current status and expected short-term evolutions. Stratospheric airplanes require very light wing loading, which has been demonstrated to be feasible but currently limits their payload mass to few tenths of kilograms. On the other hand, airships need to be large and operationally complex but their potential to hover carrying hundreds of kilograms with reasonable power supply make them true pseudo-satellites with enormous commercial interest. This paper provides useful information on the relative importance of the technology evolutions, as well as on the selection of the proper platform for each application or set of payload requirements. The authors envisage prompt availability of both types of HAPS, aerodynamic and aerostatic, providing unprecedented services.S

Stochastic design of high altitude propellers

[EN] High-Altitude Platform Stations or High-Altitude Pseudo-Satellites (HAPS) use propulsion systems which are commonly based on propellers. In this paper, an algorithm for the design of those propellers considering uncertainties is developed and applied. The algorithm is based on the non intrusive polynomial chaos expansion scheme, which converts the stochastic design problem into an equivalent deterministic one. Two uncertainties are studied and characterized: 1) the stratospheric wind fluctuations using reanalysis datasets and 2) the variability of the aerodynamic coefficients caused by the low Reynolds number. The results of the method are analyzed to tackle how relevant the uncertainties are in the propulsion of the stratospheric platforms. The case of study is an ideal stratospheric airship that operates at a mean wind speed of 9 m/s and requires a thrust of 100 N, both uncertain magnitudes. The propeller is built on NACA4412 airfoils and the cost function to be maximized is the mean net propulsion efficiency. The new method provides a relevant gain in the mean efficiency when compared with the deterministic optimization.S

An analysis and enhanced proposal of atmospheric boundary layer wind modelling techniques for automation of air traffic management

Production and hosting by Elsevier[EN] The air traffic management automation imposes stringent requirements on the weather models, in such a way that they should be able to provide reliable short-time forecasts in digital formats in almost real time. The atmospheric boundary layer is one of the regions where aircraft operation and coordination are critical and therefore atmospheric model performance is also vital. This paper presents conventional and innovative techniques to improve the accuracy in the forecasting of winds in the lower atmospheric layer, proposing mechanisms to develop better models including deterministic and stochastic simulations. Accuracy is improved by optimizing the grid, assimilating observations in cycling simulations and managing a number of ensemble members. An operation-driven post-processing stage helps to incorporate detailed terrain definitions and real-time observations without re-running the model. The improvements are checked against mesoscale weather simulations at different scales and a dedicated flight campaign. The results show good performance of the model without sensitively increasing the required throughput.SIBoeing Research & Technology Europ

Stochastic optimization of high-altitude airship envelopes based on kriging method

[EN] High-altitude airships can be used to transport substantial payloads to the stratosphere and remain there over long periods of time. In this paper, an algorithm for the design of high-altitude airship envelopes, accounting for uncertainties, is developed and applied. The algorithm is based on the non-intrusive polynomial chaos expansion scheme, which is employed to build a stochastic kriging metamodel. Two uncertainties are examined and characterized: 1) the stratospheric wind fluctuations using reanalysis datasets and 2) the variability in the turbulence levels. The method results are discussed to address the relevancy of the uncertainties. It is found that the drag coefficient of stratospheric envelopes can vary by as much as 30 percent. As a case of study, an ideal stratospheric airship is considered, operating at an altitude of 20 km, at a latitude of 30cN and carrying a payload of 250 kg. The baseline design follows the shape of the ZHIYUAN-1 envelope and the cost function to be minimized is the average mission drag coefficient. Due to the new method, a significant reduction (4%) of the average drag of the aircraft is achieved.S

Atmospheric Boundary Layer Wind Profile Estimation Using Neural Networks Applied to Lidar Measurements

[EN] This paper introduces a new methodology for estimating the wind profile within the ABL (Atmospheric Boundary Layer) using a neural network and a single-point near-ground measurement. An important advantage of this solution when compared with others available in the literature is that it only requires near surface measurements for the prognosis once the neural network is trained. Another advantage is that it can be used to study the wind profile temporal evolution. This work uses data collected by a lidar sensor located at the Universidad de León (Spain). The neural network best configuration was determined using sensibility analyses. The result is a multilayer perceptron with three layers for each altitude: the input layer has six nodes for the last three measurements, the second has 128 nodes and the third consists of two nodes that provide u and v. The proposed method has better performance than traditional methods. The obtained wind profile information obtained is useful for multiple applications, such as preliminary calculations of the wind resource or CFD models.S

Atmospheric Boundary Layer Wind Profile Estimation Using Neural Networks, Mesoscale Models, and LiDAR Measurements

[EN] This paper introduces a novel methodology that estimates the wind profile within the ABL by using a neural network along with predictions from a mesoscale model in conjunction with a single near-surface measurement. A major advantage of this solution compared to other solutions available in the literature is that it requires only near-surface measurements for prediction once the neural network has been trained. An additional advantage is the fact that it can be potentially used to explore the time evolution of the wind profile. Data collected by a LiDAR sensor located at the University of León (Spain) is used in the present research. The information obtained from the wind profile is valuable for multiple applications, such as preliminary calculations of the wind asset or CFD modeling.SIERDF A way of making Europ

Advances in CFD Modeling of Urban Wind Applied to Aerial Mobility

[EN] The feasibility, safety, and efficiency of a drone mission in an urban environment are heavily influenced by atmospheric conditions. However, numerical meteorological models cannot cope with fine-grained grids capturing urban geometries; they are typically tuned for best resolutions ranging from 1 to 10 km. To enable urban air mobility, new now-casting techniques are being developed based on different techniques, such as data assimilation, variational analysis, machine-learning algorithms, and time series analysis. Most of these methods require generating an urban wind field database using CFD codes coupled with the mesoscale models. The quality and accuracy of that database determines the accuracy of the now-casting techniques. This review describes the latest advances in CFD simulations applied to urban wind and the alternatives that exist for the coupling with the mesoscale model. First, the distinct turbulence models are introduced, analyzing their advantages and limitations. Secondly, a study of the meshing is introduced, exploring how it has to be adapted to the characteristics of the urban environment. Then, the several alternatives for the definition of the boundary conditions and the interpolation methods for the initial conditions are described. As a key step, the available order reduction methods applicable to the models are presented, so the size and operability of the wind database can be reduced as much as possible. Finally, the data assimilation techniques and the model validation are presented.S

Aerodynamic optimization of propellers for High Altitude Pseudo-Satellites

[EN] The propulsion system of High-Altitude Platform Stations or High-Altitude Pseudo-Satellites (HAPS) is commonly based on propellers. The properties of the atmosphere at those high altitudes and the characteristic speed of HAPS entail that the flight is performed at very low Reynolds numbers. Hence, the aerodynamic behavior of the propeller sections changes substantially from the hub to the tip of the blades. Under those circumstances, the ordinary methods to develop optimized propellers are not useful and must be modified. We present a method of propeller design adapted to HAPS features. It combines traditional solutions with modern numerical tools. Specifically, Theodorsen analytical theory is used to minimize induced drag. This process leaves one free parameter that it is fixed optimizing a cost function depending on the Reynolds number with a viscous-potential numerical code. It leads to an optimal determination of the geometrical characteristics of the propeller, i.e., chord and pitch distribution, increasing its total efficiency. The resulting algorithm has low computational requirements what makes it very appropriate for the preliminary design of HAPS missions, when it is necessary to simulate many different cases. That methodology has been applied to a relatively small HAPS airship with a wind speed of 10 m/s and required thrust of 100 N. The propeller is assumed to be made up of NACA4412 airfoils and the cost function to be minimized is given by the ratio of the 2D drag and lift coefficients. With those conditions we perform a parametric analysis where different combinations of diameters, thrust coefficients, and propeller advance ratios are considered. Over a Reynolds number range from 103 to 106, the new method provides a gain about 5% in the propeller efficiency when compared with the ordinary design procedure that employs a constant Reynolds number. That gain is of utmost importance for HAPS operations, since, for example, it allows an increase in the payload of up to 25% for a 90 meters long airship.S

New plant species presents in the Sierra de la Demanda (Sistema Ibérico, La Rioja, Spain)

Se citan y comentan una serie de taxones hallados en la Sierra de la Demanda (La Rioja, España), cuya presencia en la provincia era poco o nada conocida