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AbstractInputs of silver nanoparticles (AgNPs) to marine waters continue to increase yet mechanisms of AgNPs toxicity to marine phytoplankton are still not well resolved. This study reports a series of toxicity experiments on a representative coastal marine diatom speciesChaetoceros curvisetususing the reference AgNP, NM-300K. Exposure to AgNPs resulted in photosynthetic impairment and loss of diatom biomass in proportion to the supplied AgNP dose. The underlying mechanism of toxicity was explored via comparing biological responses in parallel experiments. Diatom responses to AgNP, free Ag(I) species, and dialysis bag-retained AgNP treatments showed marked similarity, pointing towards a dominant role of Ag(I) species uptake, rather than NPs themselves, in inducing the toxic response. In marked contrast to previous studies, addition of the organic complexing agent cysteine (Cys) alongside Ag only marginally moderated toxicity, implying AgCys−complexes were bioavailable to this diatom species. A preliminary field experiment with a natural phytoplankton community in the southeast Atlantic Ocean showed no significant toxic response at a NM-300 K concentration that resulted in ~40% biomass loss in the culture studies, suggesting a modulating effect of natural seawaters on Ag toxicity.

The electric vehicle is presented as an environmental friendly alternative to common vehicles and as the future of transportation. However, car manufacturers consider that electric vehicle batteries are not useful for traction purposes when they reach a state of health of 80%. Thus, as a matter of fact, these batteries are sold knowing that they have a premature obsolescence, as they still have 80% of useful capacity that could be used elsewhere. This study analyzes economically and in terms of ageing performance the possibility to provide a second life to these batteries in buildings. The study presents several scenarios depending on the battery use, considering independent buildings or getting closer to the concept of smart grid with demand response services where buildings could participate in secondary electricity markets by means of an energy aggregator. Moreover, the study analyzes the existing European markets that allow aggregated demand response services. Results show that, effectively, the reuse of batteries for residential purposes might not be the best economical option even though their lifespan is enlarged four years more. Nonetheless, if they are able to participate in secondary electricity markets in addition to their normal use in buildings, the business becomes juicy enough having a relatively low impact on ageing. The promotion of electric vehicle battery reuse is necessary, as there is a large amount of batteries with a huge useful potential in stationary applications coming in the nearby future from the electric vehicles that have been sold during the last five years. If possible, car manufacturers should consider eco-design in order to facilitate this battery repurposing and lifespan enlargement. Peer Reviewed

Electric Vehicles (EVs) have seen significant growth in sales recently and it is not clear how power systems will support the charging of a great number of vehicles. This paper proposes a methodology which allows the aggregated EV charging demand to be determined. The methodology applied to obtain the model is based on an agent-based approach to calculate the EV charging demand in a certain area. This model simulates each EV driver to consider its EV model characteristics, mobility needs, and charging processes required to reach its destination. This methodology also permits to consider social and economic variables. Furthermore, the model is stochastic, in order to consider the random pattern of some variables. The model is applied to Barcelona’s (Spain) mobility pattern and uses the 37-node IEEE test feeder adapted to common distribution grid characteristics from Barcelona. The corresponding grid impact is analyzed in terms of voltage drop and four charging strategies are compared. The case study indicates that the variability in scenarios without control is relevant, but not in scenarios with control. Moreover, the voltages do not reach the minimum voltage allowed, but the MV/LV substations could exceed their capacities. Finally, it is determined that all EVs can charge during the valley without any negative effect on the distribution grid. In conclusion, it is determined that the methodology presented allows the EV charging demand to be calculated, considering different variables, to obtain better accuracy in the results.