The introduction of 8x8 MIMO and carrier aggregation in the 3GPP LTE Rel. 10 opens up for increased user throughput. The potential gains using these techniques have been evaluated in a field measurement campaign with a testbed implementation. A downlink throughput exceeding 1 Gbps has been achieved combining 8x8 MIMO in an outdoor macro scenario with carrier aggregation using three component carriers (3x20 MHz). The relation between the achievable throughput and the channel richness arising from the physical environment and antenna spacing was demonstrated. The performance of MIMO setups ranging from 1x2 up to 8x8 was evaluated in indoor-toindoor, outdoor-to-indoor, and outdoor-to-outdoor deployments. It was observed that each added transmit or receive antenna increased the throughput. These gains were achieved with a compact UE antenna that is reasonable in size for implementation in a consumer device.

Neste artigo é apresentado o controle linear de torque de um motor síncrono de ímãs permanentes interiores funcionando nas regiões de torque constante e de potência constante. O controle de torque constante é implementado através da curva de máximo torque por Ampère do motor. A tensão de terminal do estator é mantida constante ao longo da região de enfraquecimento mediante o controle da reação de armadura. Para melhorar a resposta dinâmica do controle, o controle de máximo torque por Ampère é estendido à região de enfraquecimento parcial de campo, que é uma região intermediária de velocidade. Resultados de simulação computacional e experimentais são obtidos com o objetivo de validar os métodos de controle propostos.

No abstract

Over the last decade, the Antarctic continent has been the object of intensive scientific programmes. However, the emphasis of these studies rarely focuses on the Antarctic as a source of potential elements such as mercury. The release of mercury to the environment is known to occur at Deception Island, associated with volcanic activity. In this study, a 3D hydrodynamic model was used to assess the role of water circulation on the dispersion of released mercury. Sea level variation and tidal circulation data were obtained. Residence time was calculated using two different approaches. Internal tide generation in summer and winter were recognized and the barotropic tidal components obtained. Lagrangian tracers were used to depict particle circulation (simulating particulate mercury) in a three month summer simulation for barotropic and baroclinic conditions. The results show that particles accumulate in the northern and western parts of the bay. It is acknowledged that the results of the 3D model are associated with a non-negligible uncertainty, which can only be reduced with an ongoing commitment to monitoring. The findings of this study indicate that mercury accumulation is occurring in Port Foster (Deception Island), which is a potential threat to the local ecosystem.