Browsing by Issue Date, starting with "2021-04-29"
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- Fractal nature of advanced Ni-based superalloys solidified on board the international space stationPublication . Mitic, Vojislav; Serpa, Cristina; Ilic, Ivana; Mohr, Markus; Fecht, Hans-Jorgothers. Therefore, designing, improving and predicting advanced material properties is a crucial necessity. The high temperature creep and corrosion resistance of Ni-based superalloys makes them important materials for turbine blades in aircraft engines and land-based power plants. The investment casting process of turbine blades is costly and time consuming, which makes process simulations a necessity. These simulations require fundamental models for the microstructure formation. In this paper, we present advanced analytical techniques in describing the microstructures obtained experimentally and analyzed on different sample's cross-sectional images. The samples have been processed on board the International Space Station using the MSL-EML device based on electromagnetic levitation principles. We applied several aspects of fractal analysis and obtained important results regarding fractals and Hausdorff dimensions related to the surface and structural characteristics of CMSX-10 samples. Using scanning electron microscopy (SEM), Zeiss LEO 1550, we analyzed the microstructure of samples solidified in space and successfully performed the fractal reconstruction of the sample's morphology. We extended the fractal analysis on the microscopic images based on samples solidified on earth and established new frontiers on the advanced structures prediction.
- Textile antenna for first-person view gogglesPublication . André, Luís; Pinho, Pedro; Gouveia, Carolina; Loss, CarolineUnmanned Aerial Vehicles, also known as drones, are vehicles controlled remotely. First-Person View (FPV) technology allows these vehicles to have greater versatility and be more easily piloted. The antennas currently used for video transmission are bulky and uncomfortable, so there is a need for this volume to be reduced to increase portability, being this the focus of the paper. The antenna was developed in textile materials to reduce its size and weight, as these materials allow for a better comfort and a reduced footprint. This paper presents a microstrip array adapted for the frequencies used in FPV video transmission. The designed textile antenna was compared with a commercially available rigid antenna used for this transmission. The comparison shows promising results for the antenna made of textile materials. The main goal of increasing the comfort and portability of the FPV goggles was achieved.
- Comentarios a la «Portaria» n.º 67/2021, de 17 de marzo, por el que se establecen los requisitos mínimos obligatorios que deben ser incluidos en los planes de cogestión de áreas protegidasPublication . Sereno, AmparoEl modelo de cogestión en áreas protegidas estaba ya previsto en la Resolución del Consejo de Ministros n.o 55/2018, de 7 de mayo, que aprobó la Estrategia Nacional de Conservación de la Naturaleza y Biodiversidad 2030 con la finalidad de establecer acuerdos de gestión colaborativa con las entidades presentes en el territorio de las referidas áreas protegidas. Este modelo fue adoptado e desarrollado por e “Decreto-Lei” n.o 116/2019, de 21 de agosto. De acuerdo con el mismo, las asociaciones de municipios ya constituidas, o que vayan a constituirse futuramente pueden participar en la gestión de áreas protegidas de ámbito nacional, siendo reconocidas como grupos de acción locales con capacidad para gestionar fondos europeos para el desarrollo local de base comunitaria. Así, se persigue la finalidad de imprimir una dinámica de gestión de proximidad en las áreas protegidas, bien como aplicar los principios de subsidiariedad, descentralización administrativa y participación de los órganos municipales en la respectiva gestión, en virtud de lo previsto en el artículo 20o c) de la Ley n.o 50/2018, de 16 de agosto.