Inácio, David, João Pina, João Martins, Mário Ventim Neves, and Alfredo Álvarez. "
Lumped Parameters Equivalent Circuit of a Superconducting Hysteresis Motor."
EUCAS Conference 2011. Vol. 36. 2012. 975-979.
AbstractThe potential advantage of using superconducting materials in electrical devices is well described in the literature. The electromagnetic properties of these materials make them unique for several applications, such as, e.g. electrical machines and drives, fault current applications, or superconducting magnetic energy storage. In the development of electromechanical conversion devices, superconducting materials are used foreseeing mainly a decrease in the device dimensions or a performance improvement for the same active volume. To guarantee a good application of this kind of materials it is important to describe and model the phenomena that characterize their operation under different regimes. In this paper, a study based in FEM simulations of a motor with bulk superconductor in the rotor is carried out, with the purpose of understand, quantify and qualify which phenomena are present in the different regimes of the motor, leading to obtaining an equivalent electrical circuit with lumped parameters.
Carvalho, H., S. A. Azevedo, and V. Cruz-Machado. "
Supply chain resilience: an empirical model."
Euroma 2012. Amsterdam, Netherlands 2012.
AbstractThis paper proposes a model for management of supply chain resilience. To this end the structured content analysis of media news is used to analyze a sample constituted by sixty two documents containing evidences of seventy seven companies that were affected by the Japan 2011 earthquake. The sample provides evidences that companies failed to sustain their operations mainly because capacity shortages and material shortages. Also provides empirical evidence of twelve resilience practices to reduce the disturbance severity and the recovery time. Based on these findings four propositions were made and aggregated to propose a model for supply chain resilience management.
de Calheiros Velozo, A., G. Lavareda, C. Nunes de Carvalho, and A. Amaral. "
Thermal dehydrogenation of amorphous silicon deposited on c-Si: Effect of the substrate temperature during deposition."
PHYSICA STATUS SOLIDI C: CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 9, NO 10-11. Eds. S. Pizzini, G. Kissinger, H. YamadaKaneta, and J. Kang. Vol. 9. Physica Status Solidi C-Current Topics in Solid State Physics, 9. European Mat Res Soc (E-MRS), 2012. 2198-2202.
AbstractSamples of doped and undoped a-Si: H were deposited at temperatures ranging from 100 degrees C to 350 degrees C and then submitted to different dehydrogenation temperatures (from 350 degrees C to 550 degrees C) and times (from 1 h to 4 h). a-Si: H films were characterised after deposition through the measurements of specific material parameters such as: the optical gap, the conductivity at 25 degrees C, the thermal activation energy of conductivity and its hydrogen content. Hydrogen content was measured after each thermal treatment. Substrate dopant contamination from phosphorus-doped a-Si thin films was evaluated by SIMS after complete dehydrogenation and a junction depth of 0.1 mu m was obtained. Dehydrogenation results show a strong dependence of the hydrogen content of the as-deposited film on the deposition temperature. Nevertheless, the dehydrogenation temperature seems to determine the final H content in a way almost independent from the initial content in the sample. H richer films dehydrogenate faster than films with lower hydrogen concentration. (C) 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
de Calheiros Velozo, A., G. Lavareda, C. Nunes de Carvalho, and A. Amaral. "
Thermal dehydrogenation of amorphous silicon deposited on c-Si: Effect of the substrate temperature during deposition."
PHYSICA STATUS SOLIDI C: CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 9, NO 10-11. Eds. S. Pizzini, G. Kissinger, H. YamadaKaneta, and J. Kang. Vol. 9. Physica Status Solidi C-Current Topics in Solid State Physics, 9. European Mat Res Soc (E-MRS), 2012. 2198-2202.
AbstractSamples of doped and undoped a-Si: H were deposited at temperatures ranging from 100 degrees C to 350 degrees C and then submitted to different dehydrogenation temperatures (from 350 degrees C to 550 degrees C) and times (from 1 h to 4 h). a-Si: H films were characterised after deposition through the measurements of specific material parameters such as: the optical gap, the conductivity at 25 degrees C, the thermal activation energy of conductivity and its hydrogen content. Hydrogen content was measured after each thermal treatment. Substrate dopant contamination from phosphorus-doped a-Si thin films was evaluated by SIMS after complete dehydrogenation and a junction depth of 0.1 mu m was obtained. Dehydrogenation results show a strong dependence of the hydrogen content of the as-deposited film on the deposition temperature. Nevertheless, the dehydrogenation temperature seems to determine the final H content in a way almost independent from the initial content in the sample. H richer films dehydrogenate faster than films with lower hydrogen concentration. (C) 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim