Browsing by Author "Correia, J.B."
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- An integrated program of characterisation and effects evaluation of nanoparticles in the aquatic environemntPublication . Picado, Ana; Correia, J.B.; Mendonça, E.; Diniz, M. S.
- Behavior of Cu-Y2O3 and CuCrZr-Y2O3 composites before and after irradiationPublication . Martins, Ricardo; Antão, Francisco; Correia, J.B.; Tejado, Elena; Pastor, Jose Ygnacio; Galatanu, Andrei; Almeida Carvalho, Patricia; Alves, E.; Dias, MartaABSTRACT: The Cu-Y2O3 and CuCrZr-Y2O3 materials have been devised as thermal barriers in nuclear fusion reactors. It is expected that in the nuclear environments, the materials should be working on extreme conditions of irradiation. In this work the Cu-Y2O3 and CuCrZr-Y2O3 were prepared and then irradiated in order to understand the surface irradiation resistance of the material. The composites were prepared in a glove box and consolidated with spark plasma sintering. The microstructures revealed regions of Y2O3 dispersion and Y2O3 agglomerates both in the Cu matrix and in the CuCrZr. The irradiated samples did not show any surface modification indicating that the materials seem to be irradiation resistant in the present situation. The thermal conductivity values for all the samples measured are lower than pure Cu and higher than pure W, however are higher than those expected, and therefore, the application of these materials as thermal barriers is compromised.
- Blistering of W–Ta composites at different irradiation energiesPublication . Mateus, R.; Dias, Marta; Lopes, J.; Rocha, J.; Catarino, N.; Duarte, P.; Gomes, R. B.; Silva, C.; Fernandes, H.; Livramento, Vanessa; Carvalho, Patricia Almeida; Alves, E.; Hanada, K.; Correia, J.B.Pure tungsten and tantalum plates and tungsten–tantalum composites produced via mechanical alloying and spark plasma sintering were bombarded with He+ and D+ energetic ion beams and deuterium plasmas. The aim of this experiment is to study the effects caused by individual helium and deuterium exposures and to evidence that the modifications induced in the composites at different irradiation energies could be followed by irradiating the pristine constituent elements under the same experimental conditions, which is relevant considering the development of tailored composites for fusion applications. Higher D retentions, especially in tungsten, and superficial blistering are observed in both components after helium exposure. The blistering is magnified in the tantalum phase of composites due to its higher ductility and to water vapour production under deuterium irradiation. At lower irradiation energies the induced effects are minor. After plasma exposure, the presence of tantalum does not increase the D content in the composites.
- A brief summary of the progress on the EFDA tungsten materials programPublication . Rieth, M.; Dudarev, S. L.; Vicente, S. M. Gonzalez de; Aktaa, J.; Ahlgren, T.; Antusch, S.; Armstrong, D. E. J.; Balden, M.; Baluc, N.; Barthe, M. F.; Basuki, W. W.; Battabyal, M.; Becquart, C. S.; Blagoeva, D.; Boldyryeva, H.; Brinkmann, J.; Celino, M.; Ciupinski, L.; Correia, J.B.; De Backer, A.; Domain, C.; Gaganidze, E.; Garcia-Rosales, C.; Gibson, J.; Gilbert, M. R.; Giesepponi, S.; Gludovatz, B.; Greuner, H.; Heinola, K.; Hoschen, T.; Hoffmann, A.; Holstein, N.; Koch, F.; Krauss, W.; Li, H.; Linding, S.; Linke, J.; Linsmeier, Ch.; Lopez-Ruiz, P.; Maier, H.; Matejicek, J.; Mishra, T. P.; Muhammed, M.; Munoz, A.; Muzyk, M.; Nordlund, K.; Nguyen-Manh, D.; Opschoor, J.; Ordas, N.; Palacios, T.; Pintsuk, G.; Pippan, R.; Reiser, J.; Riesch, J.; Roberts, S. G.; Romaner, L.; Rosinski, M.; Sanchez, M.; Schulmeyer, W.; Traxler, H.; Urena, A.; van der Laan, J. G; Veleva, L.; Wahlberg, S.; Walter, M.; Weber, T.; Weitkamp, T.; Wurster, S.; Yar, M. A.; You, J. H.; Zivelonghi, A.The long-term objective of the European Fusion Development Agreement (EFDA) fusion materials programme is to develop structural and armor materials in combination with the necessary production and fabrication technologies for reactor concepts beyond the International Thermonuclear Experimental Reactor. The programmatic roadmap is structured into four engineering research lines which comprise fabrication process development, structural material development, armor material optimization, and irradiation performance testing, which are complemented by a fundamental research programme on ‘‘Materials Science and Modeling.’’ This paper presents the current research status of the EFDA experimental and testing investigations, and gives a detailed overview of the latest results on materials research, fabrication, joining, high heat flux testing, plasticity studies, modeling, and validation experiments.
- Caracterização de fases de carbono nano estruturado em compósitos de cobre/carbonoPublication . Nunes, D.; Livramento, Vanessa; Correia, J.B.; Almeida Carvalho, Patricia; Alves, L. C.; Vilarigues, M.
- Characterization of Cu2ZnSn(SSe)4 monograin powders by FE-SEMPublication . Neves, Filipe; Livramento, Vanessa; Martins, Isabel M.; Esperto, Luís; Santos, Mário J. G.; Correia, J.B.; Muska, K.; Holopainen, T.The design and synthesis of high-efficiency materials to convert solar to electrical energy is an increasingly important research field. Within the photovoltaic technologies, crystalline Si have an 80% share while the remaining 20% are mostly thin film solar cells based on Cu(In,Ga)(S,Se)2 (CIGSSe) and CdTe [1,2].
- Characterization of Cu2ZnSn(SSe)4 monograin powders by FE-SEMPublication . Neves, Filipe; Livramento, Vanessa; Martins, Isabel M.; Esperto, Luís; Santos, Mário J. G.; Correia, J.B.; Muska, K.; Holopainen, T.The design and synthesis of high-efficiency materials to convert solar to electrical energy is an increasingly important research field. Within the photovoltaic technologies, crystalline Si have an 80% share while the remaining 20% are mostly thin film solar cells based on Cu(In,Ga)(S,Se)2 (CIGSSe) and CdTe [1,2]. However,the cost, the abundance and the environmental impact of the elemental components cannot be neglected. For these reasons, Cu2ZnSnS4 (CZTS), Cu2ZnSnSe4 (CZTSe)and their solid solutions CZTSSe has attracted much attention recently since they can provide the development of cost competitive solar cells. The CZTS-based solar cells consist of earth abundant and relatively inexpensive elements and represent an environmentally friendly alternative compared to the above mentioned systems [3]. The energy conversion efficiency of the CZTS-based solar cells has increased from 0.66% in 1996 to 11.1% recently [4].
- Characterization of smart MARFOS NiTi shape memory alloysPublication . Neves, Filipe; Fernandes, F. M. Braz; Martins, J.; Correia, J.B.; Oliveira, M.; Gaffet, E.; Wang, T. Y.; Lattemann, M.; Suffner, J.; Hahn, H.In the present study, structural characterization of NiTi smart shape memory al-loys (SMAs), produced by an alternative powder metallurgy approach named mechanically ac-tivated reactive forging (MARFOS), was carried out by means of transmission electron micros-copy (TEM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). It was observed that MARFOS materials had a multiphase nanocrystalline structure. In addition, the transformation behaviour associated with the shape memory effect of the MARFOS aged mate-rials was studied with differential scanning calorimetry (DSC). Multiple-step martensitic trans-formations could be observed in aged materials.
- Consolidation of W–Ta composites: hot isostatic pressing and spark and pulse plasma sinteringPublication . Dias, Marta; Guerreiro, F.; Correia, J.B.; Galatanu, Andrei; Rosinski, M.; Monge, M. A.; Munoz, A.; Alves, E.; Almeida Carvalho, PatriciaComposites consisting of tantalum fiber/powder dispersed in a nanostructured W matrix have been consolidated by spark and pulse plasma sintering as well as by hot isostatic pressing. The microstructural observations revealed that the tungsten–tantalum fiber composites consolidated by hot isostatic pressing and pulse plasma sintering presented a continuous layer of Ta2O5 phase at the W/Ta interfaces, while the samples consolidated by spark plasma sintering evidenced a Ta + Ta2O5 eutectic mixture due to the higher temperature of this consolidation process. Similar results have been obtained for the tungsten–tantalum powder composites. A (W, Ta) solid solution was detected around the prior nanostructured W particles in tungsten–tantalum powder composites consolidated by spark and pulse plasma sintering. Higher densifications were obtained for composites consolidated by hot isostatic pressing and pulse plasma sintering.
- Conversão de edifícios existentes em nzeb através da integração de energias renováveis, de micro-redes e de soluções de eficiência energéticaPublication . Estanqueiro, Ana; Joyce, A; Aelenei, Laura Elena; Facão, Jorge; Rodrigues, Carlos; Loureiro, David; Teixeira, J.; Correia, J.B.; Ramalho, Álvaro; Camelo, Susana; Silva, Carlos; Neto, Rui C.RESUMO: O Projeto IMPROVEMENT “Integration of combined cooling, heating and power microgrids in zero-energy public buildings under high power quality and continuity of service requirements” é um projeto financiado pelo Programa INTERREG SUDOE, de cariz marcadamente multidisciplinar e que reúne competências da área de integração e modelação de sistemas energéticos, da gestão de energia em edifícios, de energias renováveis, micro-redes inteligentes e sistemas de monitorização e gestão de consumo. Tem ainda como objetivo geral renovar edifícios públicos existentes, convertendo-os em edifícios com necessidades de energia quase nulas (NZEB), e para tal integra micro-redes com fontes renováveis e geração combinada de calor, frio, eletricidade, equipadas com sistemas de armazenamento.