This paper discusses the idea of vertical wake deflection for offshore wind turbines using active ballast control. First, the concept of active ballast control for changing the attitude of an ...offshore wind energy semi-submersible platform is presented and briefly explored. Next, the influence of vertical wake deflection on the wake behavior and power production of a cluster of two wind turbines is studied through wind tunnel experiments and LES simulations. Results show that vertical deflection changes substantially the wake characteristics and affects the inflow at a downstream wind turbine in terms of available kinetic energy and turbulence intensity. For the most favorable case considered here, the cluster power was increased by approximately 8%.
This study describes the development of an up-flow tubular air-cathode microbial fuel cell (MFC) bioreactor inoculated with a consortium of Shewanella oneidensis and Clostridium butyricum, fed with ...dairy wastewater (DW). Due to the high organic load of dairy wastewater, the MFC was operated using different strategies for the start-up (30 days) and the subsequent treatment phases (phase 1: 75 days; phase 2: 30 days). The removals of total chemical and biochemical oxygen demand (TCOD and TBOD) were 94 and 96%, under external resistance of 1.0 kΩ (phase 1), and 96 and 97%, under external resistance of 0.3 kΩ (phase 2). In addition, the MFC treatment provided high efficiency for the removal of organic nitrogen (47%), phosphorus (95%), nitrate (100%), and sulfate (75%). The MFC bioreactor delivered maximum power density of 3.5 W m−3 and current density of 1.1 A m−3 at the end of phase 1, and 2.4 W m−3 and 2.4 A m−3 in phase 2, but achieved modest Coulombic efficiency of 2.1% (phase 1) and 4.4% (phase 2), probably due to other metabolic pathways, besides the electrogenic one. Evaluation of the toxicity of the treated DW at two different trophic levels revealed no acute toxic effects towards Daphnia similis (immobilization less than 20%), but statistically significant chronic toxic effects towards Raphidocelis subcapitata (60% inhibition, using a concentrated sample). The findings indicated that the MFC constructed here had excellent potential for dairy wastewater treatment and energy recovery, and that toxicity assessment should be integrated with the MFC process.
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•First use of toxicity tests with a microbial fuel cell treating dairy wastewater.•Up-flow microbial fuel cell fed by dairy wastewater delivered 3.5 W m−3.•The system was stable for at least 3 months.•Removal of COD, BOD, nitrate, and phosphorus exceeded 95%.
The wave energy sector has not reached a sufficient level of maturity for commercial competitiveness, thus requiring further efforts towards optimizing existing technologies and making wave energy a ...viable alternative to bolster energy mixes. Usually, these efforts are supported by physical and numerical modelling of complex physical phenomena, which require extensive resources and time to obtain reliable, yet limited results. To complement these approaches, artificial-intelligence-based techniques (AI) are gaining increasing interest, given their computational speed and capability of searching large solution spaces and/or identifying key study patterns. Under this scope, this paper presents a comprehensive review on the use of computational systems and AI-based techniques to wave climate and energy resource studies. The paper reviews different optimization methods, analyses their application to extreme events and examines their use in wave propagation and forecasting, which are pivotal towards ensuring survivability and assessing the local wave operational conditions, respectively. The use of AI has shown promising results in improving the efficiency, accuracy and reliability of wave predictions and can enable a more thorough and automated sweep of alternative design solutions, within a more reasonable timeframe and at a lower computational cost. However, the particularities of each case study still limit generalizations, although some application patterns have been identified—such as the frequent use of neural networks.
The impacts of anthropic activities have had profound effects on the nitrogen (N) and phosphorus (P) cycles in many aquatic ecosystems. We investigated the spatial and temporal distributions of ...carbon (C), N, and P in the sediments of a tropical Paiva Castro Reservoir (São Paulo, Brazil), as well as their release and retention in the system. In 2010, surface sediments were collected at nine sites in the reservoir, and a core was obtained in the limnetic zone, in 2010. The core was dated using the
210
Pb technique. The organic C content was estimated from organic matter concentration, which was measured by the loss-on-ignition method, and the concentrations of P and N were determined by spectrophotometry. Marked spatial heterogeneity in the Paiva Castro sediments associated with both natural variations in the water body and variations induced by human impacts was observed. Heterogeneity was evidenced by a decrease in the allochthonous contribution of organic matter (C/N) in the upstream-downstream direction and increases of N and P, mainly associated with water flows in the different compartments of the reservoir. In the core, C and N concentrations display significant positive correlations with increases in population and agricultural activities in the drainage basin through time. The C/P molar ratios in surface sediments are indicative of human impacts in the region, as C:P ratios in the sediment are low (7.8:1) compared to the Redfield ratio (C:P = 108:1). Predominance of oxic conditions at the sediment surface and particles sizes < 63 μm provided favorable conditions for P retention in the sediments, which helps prevent eutrophication. Approaches used in this research should be extended to other locations, especially in mesotrophic and oligotrophic reservoirs, to provide information on historical impacts in such aquatic ecosystems.
Seaports are highly energy demanding infrastructures and are exposed to wave energy, which is an abundant resource and largely unexploited. As a result, there has been a rising interest in ...integrating wave energy converters (WEC) into the breakwaters of seaports. The present work analyzes the performance of an innovative hybrid WEC module combining an oscillating water column (OWC) and an overtopping device (OWEC) integrated into a rubble mound breakwater, based on results of a physical model study carried out at a geometrical scale of 1:50. Before the experimental tests, the device’s performance was numerically optimized using ANSYS Fluent and WOPSim v3.11. The wave power captured by the hybrid WEC was calculated and the performance of the two harvesting principles discussed. It was demonstrated that hybridization could lead to systems with higher efficiencies than its individual components, for a broader range of wave conditions. The chosen concepts were found to complement each other: the OWEC was more efficient for the lower wave periods tested and the OWC for the higher. Consequently, the power production of the hybrid WEC was found to be less dependent on the wave’s characteristics.
The goal of this work was to evaluate the efficiency of an air-cathode microbial fuel cell (MFC), operating in semi-continuous downflow mode. The MFC was inoculated with a consortium of Shewanella ...oneidensis and Clostridium butyricum. It was fed using a synthetic medium with progressively increasing dairy wastewater (DWW) concentrations in the startup (15 days), acclimatization (30 days), and treatment (75 days) phases. This approach enabled removal of 89% of the total COD and 91% of the total BOD, after 90 days of operation. These efficiencies were improved with step change of external resistance (Rext.) from 1.0 to 0.5 kΩ. Electrochemical impedance spectroscopy analysis indicated the formation of more complex biointerface associated with change of Rext. The maximum power density was 3.5 W∙m−3 at 1.0 A∙m−3, during the startup, while the Coulombic efficiency (CE) was 4.5 at the end of the operation. The MFC process showed high efficiency for the removal of organic nitrogen (85%), phosphorus (92%), nitrate (100%), and sulfate (88%). Additionally, the treated DWW effluent presented no acute toxic effect towards Daphnia similis. Overall, it could be concluded that applying gradual increments of the DWW concentration resulted in highly efficient treatment.
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•Low-cost graphite cylinders electrodes acting as anode and biofilter.•Microbial fuel cell fed with real dairy wastewater delivered 1.2 W m−3.•The system was able to operate for a long time period, 120 days.•TCOD, SCOD, BOD, and sulfate were efficiently removed.•The treated dairy wastewater had no acute toxic effect on Daphnia similis.
To assess European pediatric rheumatology providers' current clinical practices and resources used in the transition from child-centered to adult-oriented care.
European pediatric rheumatologists ...were invited to complete a 17-item anonymized e-survey assessing current transition practices, transition policy awareness, and needs in advance of the publication of EULAR/PReS recommendations on transition.
The response rate was 121/276 (44%), including responses from 115 centers in 22 European Union countries. Although 32/121 (26%) responded that their centers did not offer transition services, the majority (99%) agreed that a formalized process in transitioning patients to adult care is necessary. A minority (<30%) of respondents stated that they have a written transition policy although 46% have an informal transition process. Designated staff to support transitional care were available in a minority of centers: nurse (35%), physiotherapist (15%), psychologist (15%), social worker (8%), and occupational therapist (2%). The existence of a designated team member to coordinate transition was acknowledged in many centers (64% of respondents) although just 36% use a checklist for young people as part of individualized transitional care.
This survey of European pediatric rheumatology providers regarding transitional care practices demonstrates agreement that transitional care is important, and wide variation in current provision of transition services exists.
Seaports are at the forefront of global trade networks, serving as hubs for maritime logistics and the transportation of goods and people. To meet the requirements of such networks, seaport ...authorities are investing in advanced technologies to enhance the efficiency and reliability of port infrastructures. This can be achieved through the digitalization and automation of core systems, aimed at optimizing the management and handling of both goods and people. Furthermore, a significant effort is being made towards a green energy transition at seaports, which can be supported through marine renewable sources. This promotes energy-mix diversification and autonomy, whilst reducing the noteworthy environmental footprint of seaport activities. By analyzing these pertinent topics under the scope of a review of container-terminal case studies, and these ports’ respective contexts, this paper seeks to identify pioneering smart seaports in the fields of automation, real-time management, connectivity and accessibility control. To foster the sustainable development of seaports, from an energy perspective, the potential integration with marine renewable-energy systems is considered, as well as their capabilities for meeting, even if only partially, the energy demands of seaports. By combining these fields, we attempt to construct a holistic proposal for a “model port” representing the expected evolution towards the seaports of the future.
Imidacloprid (IMI) is a neonicotinoid insecticide widely used in agriculture worldwide. This pesticide has been found in freshwater ecosystems, including Brazilian freshwaters. For this reason, ...studies are being conducted to detect the presence of IMI in freshwater and understand its effects on the aquatic biota. In the present study, the acute toxic effect of the imidacloprid commercial formulation (ICF) Galeão
®
on the Brazilian non-target aquatic organisms
Chironomus sancticaroli
and
Poecilia reticulata
was evaluated. Enzymatic activities (glutathione S-transferase (GST), catalase (CAT), and ascorbate peroxidase (APX)) were also determined. Moreover, we considered 11 studies that detected IMI concentrations up to 3.65 µg.L
−1
in 28 different Brazilian freshwaters to evaluate the acute ecological risk of IMI in these environments. From the ecotoxicological assays, we determined the LC
50
values for
C. sancticaroli
(LC
50-48 h
1.52 µg.L
−1
) and
P. reticulata
(LC
50-96 h
122.65 mg.L
−1
). The high sensitivity of
C. sancticaroli
demonstrates that this species could be used as a bioindicator in studies investigating the contamination of freshwater by IMI. Enzymatic activity changes were observed in both organisms and offered sublethal responses to the effects of the pollution by IMI on aquatic biota. Our results suggest that the presence of IMI in Brazilian aquatic ecosystems can represent a potential ecological risk for the aquatic insect populations and, consequently, cause an imbalance in these ecosystems. The present study provides relevant and comparable toxicity information that may be useful to develop public policies to protect the Brazilian aquatic ecosystem from IMI contamination.
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