Browsing by Issue Date, starting with "2021-11"
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- New proton conductive membranes of indazole- and condensed pyrazolebisphosphonic acid-Nafion membranes for PEMFCPublication . Teixeira, Fatima; Teixeira, António P. S.; Rangel, C. M.ABSTRACT: The global demands of energy are still increasing alongside many civilizational problems, notably the effects on the environment due to the overuse of traditional energy sources based on fossil fuels. New cleaner, renewable sources for sustainable energy systems are a key challenge of the 21st century society.
- Management of local citizen energy communities and bilateral contracting in multi-agent electricity marketsPublication . Algarvio, HugoABSTRACT: Over the last few decades, the electricity sector has experienced several changes, resulting in different electricity markets (EMs) models and paradigms. In particular, liberalization has led to the establishment of a wholesale market for electricity generation and a retail market for electricity retailing. In competitive EMs, customers can do the following: freely choose their electricity suppliers; invest in variable renewable energy such as solar photovoltaic; become prosumers; or form local alliances such as Citizen Energy Communities (CECs). Trading of electricity can be done in spot and derivatives markets, or by bilateral contracts. This article focuses on CECs. Specifically, it presents how agent-based local consumers can form alliances as CECs, manage their resources, and trade on EMs. It also presents a review of how agent-based systems can model and support the formation and interaction of alliances in the electricity sector. The CEC can trade electricity directly with sellers through private bilateral agreements. During the negotiation of private bilateral contracts, the CEC receives the prices and volumes of their members and according to its negotiation strategy, tries to satisfy the electricity demands of all members and reduce their costs for electricity.
- Evaluation of microalgae as bioremediation agent for poultry effluent and biostimulant for germinationPublication . Viegas, Catarina; Gouveia, Luisa; Gonçalves, Maria MargaridaABSTRACT: This work addresses how a pre-treatment involving biomass ash influences the poultry effluent's bioremediation using three microalga strains, such as Chlorella vulgaris, Chlorella protothecoides and Tetradesmus obliquus. The undiluted effluent served as the culture medium for the growth, both in batch and semi continuous modes, and the remediation efficiency and biomass production yield were quantified. The combination strategy in batch mode, allowed removal efficiency of 100% for total nitrogen, more than 80% for total phosphorus and over 70% for chemical oxygen demand. Average biomass productivities for 10 days of 94.9, 76.2 and 72.0 mg L-1 day(-1) were obtained for T. obliquus, C. vulgaris and C. protothecoides, respectively. Regarding semi-continuous strategy (28 days), the biomass productivities achieved were 245 and 194 mg L-1 day(-1) for T. obliquus and C. vulgaris, respectively. Remediation rates of 100% for total nitrogen and phosphorus, and over 92% for COD were attained. The microalga composition was assessed for protein, sugar, lipid, and ash contents. The produced biomasses were tested as biostimulant and showed a 147% increase in wheat germination index, for the C. vulgaris microalga. The use of the precipitate from the biomass ash pre-treatment as fertilizer in germination tests was also assessed and results in an increase of 26%, for 10% of precipitate incorporation.
- Dust Characterization and Its Potential Impact during the 2014-2015 Fogo Volcano Eruption (Cape Verde)Publication . Candeias, Carla; Ávila, Paula Freire; Alves, Célia; Gama, Carla; Sequeira, Cristina; Silva, E. Ferreira da; Rocha, FernandoABSTRACT: Fogo (Fogo Island) is the youngest and most active volcano of Cape Verde. The last eruption occurred in 2014-2015. Aiming to assess the dust sources that impacted the air quality during the present study period, fresh lava samples were collected, while Saharan dust intrusions and transport were modeled. Rooftop dust was also collected on the island dwellings and a mineralogical and chemical characterization was undertaken. Air quality monitors were used to obtain concentrations of atmospheric particulate matter (PM) and gaseous pollutants. The mineralogical constitution was assessed by XRD and Electron Microprobe. The pseudototal chemical concentration was performed by XRF, ICP-MS and SEM; the latter includes particles morphology. During the study, WRF-CHIMERE results showed the intrusion of desert dust which affected the air quality. Lava was classified as tephritic to basanitic, with high potassium content. The Pollution Load Index for rooftop dust was > 1 in all samples, suggesting an enrichment. Higher values were found in dust size fraction < 63 mu m, with contamination factor pointing to high enrichment of As, Ni and Pb, and very high enrichment of Cd. The non-carcinogenic hazard estimated for children suggested that health problems may arise. The carcinogenic risk was above the target risk, mostly due to As > Pb > Co. Ingestion was the main exposure route. PM10 concentrations exceeded the 24-h mean of 50 mu g/m(3) recommended by WHO. Nevertheless, TVOCs displayed levels lower than guidelines. The highest levels of CO2 were recorded in more populated villages and farthest from the volcano.
- Synthesis and photophysical properties of tetraphenylethylene derivatives as luminescent downshifting materials for organic photovoltaic applicationsPublication . Barros, Helio; Esteves, M. Alexandra; Brites, Maria JoãoABSTRACT: Luminescent Down-Shifting (LDS) is an optical approach applied in several photovoltaic (PV) technologies in which high energy solar radiation is converted to a wavelength region where the response of the photovoltaic devices is better. The use of LDS layers on organic photovoltaics (OPV) could serve two purposes: to prevent cell degradation by filtering the incident ultraviolet (UV) radiation and to improve the spectral response of PV cells at short-wavelength. This work reports, the design and synthesis of a series of tetraphenylethylene (TPE) derivatives based on TPE-A or A-pi-TPE-pi-A molecular structure featuring various electron-acceptor (A) groups. The photo-physical properties of the new LDS compounds were systematically studied in 1,4-dioxane solution and film (Zeonex) by UV-visible absorption and fluorescence spectroscopy, and electrochemical properties studied by cyclic voltammetry. Thermal stability of the new LDS compounds was evaluated by Thermogravimetric analysis (TGA). Theoretical computational studies provided evidence of existence of intramolecular charge-transfer (ICT) between frontier orbitals of donor and acceptor moieties. The good photophysical and thermal properties of the synthesized TPE derivatives, associated with high molar absorption coefficients in UV spectrum and emission maximum in the range of 476-531 nm, make them promising candidates for LDS layers in OPV application.
- History of the discovery of the ankylosaur Dracopelta zbyszewskii (Upper Jurassic), with new data about the type specimen and its localityPublication . Russo, João; Mateus, OctávioAbstract: Dracopelta zbyszewskii is a poorly known ankylosaur dinosaur from the Upper Jurassic of Portugal. Even its early history has hitherto remained problematic, mostly due to scarce recorded information. By reviewing published literature, unpublished photos and notes, and field observations, we identify the type locality as a roadcut 400 m Southeast of Praia da Assenta Sul, approximately 1 km West of Barril, Mafra. Western Portugal, and date the discovery to early 1964 and the excavation to December 1964. This improves the existing records and allows to trace the early history of the holotype, providing important historical context on one of the most complete ankylosaurs from Europe. Furthermore, we preliminarily identify additional holotype material, i.e., putative pelvic elements, right hindlimb elements (distal femur, tibia, and fibula), one ungual, ribs, and osteoderms, which will help ascertain its position within Ankylosauria. We also propose that a single repository number be used for the specimen.
- O que é Valor Sustentável: Contributo para a Sustentabilidade EmpresarialPublication . Henriques, José João M. Silva; Catarino, Justina; Camocho, David; Alexandre, JorgeRESUMO: O objectivo da Enterprise Europe Network é ajudar as empresas a inovar e a competir melhor internacionalmente. As empresas que pretendam inovar e competir podem estabelecer parcerias com as suas congéneres estrangeiras utilizando esta rede. Necessitam também de instrumentos que lhes permitam avaliar o seu desempenho. As crescentes preocupações com o Desenvolvimento Sustentável levaram ao progressivo reequacionamento das atividades empresariais tendo em conta os aspetos ambientais e sociais e não apenas os tradicionalmente utilizados na avaliação do desempenho das empresas, essencialmente os económicos e técnicos. É assim que surge a necessidade de uma atualização da metologia da Análise do Valor, passando a integrar os componentes da Sustentabilidade na definição de Valor Sustentável. O Valor Ssutentável, proposto nesta brochura, é um indicador calculado a partir da relação desempenho versus recursos envolvidos de modo a garantir esse desempenho. Tem em linha de conta a tripla linha de base da sustentabilidade e não apenas interesses economicistas contribuindo também para a circularidade da economia.
- Lignin syngas bioconversion by Butyribacterium methylotrophicum: advancing towards an integrated biorefineryPublication . Pacheco, Marta; Pinto, Filomena; Ortigueira, Joana; Silva, Carla; Gírio, FranciscoABSTRACT: Hybrid bio-thermochemical based technologies have the potential to ensure greater feedstock flexibility for the production of bioenergy and bioproducts. This study focused on the bioconversion of syngas produced from low grade technical lignin to C-2-/C-4-carboxylic acids by Butyribacterium methylotrophicum. The effects of pH, medium supplementation and the use of crude syngas were analyzed. At pH 6.0, B. methylotrophicum consumed CO, CO2 and H-2 simultaneously up to 87 mol% of carbon fixation, and the supplementation of the medium with acetate increased the production of butyrate by 6.3 times. In long-term bioreactor experiments, B. methylotrophicum produced 38.3 and 51.1 mM acetic acid and 0.7 and 2.0 mM butyric acid from synthetic and lignin syngas, respectively. Carbon fixation reached 83 and 88 mol%, respectively. The lignin syngas conversion rate decreased from 13.3 to 0.9 NmL/h throughout the assay. The appearance of a grayish pellet and cell aggregates after approximately 220 h was indicative of tar deposition. Nevertheless, the stressed cells remained metabolically active and maintained acetate and butyrate production from lignin syngas. The challenge that impurities represent in the bioconversion of crude syngas has a direct impact on syngas cleaning requirements and operation costs, supporting the pursuit for more robust and versatile acetogens.
- Optimization of Biochar Production by Co-Torrefaction of Microalgae and Lignocellulosic Biomass Using Response Surface MethodologyPublication . Viegas, Catarina; Nobre, Catarina; Correia, Ricardo; Gouveia, Luisa; Gonçalves, Maria MargaridaABSTRACT: Co-torrefaction of microalgae and lignocellulosic biomass was evaluated as a method to process microalgae sludge produced from various effluents and to obtain biochars with suitable properties for energy or material valorization. The influence of four independent variables on biochar yield and properties was evaluated by a set of experiments defined by response surface methodology (RSM). The biochars were characterized for proximate and ultimate composition, HHV, and methylene blue adsorption capacity. HHV of the biochars was positively correlated with carbonization temperature, residence time, and lignocellulosic biomass content in the feed. Co-torrefaction conditions that led to a higher yield of biochar (76.5%) with good calorific value (17.4 MJ Kg(-1)) were 250 & DEG;C, 60 min of residence time, 5% feed moisture, and 50% lignocellulosic biomass. The energy efficiency of the process was higher for lower temperatures (92.6%) but decreased abruptly with the increase of the moisture content of the feed mixture (16.9 to 57.3% for 70% moisture). Biochars produced using algal biomass grown in contaminated effluents presented high ash content and low calorific value. Dye removal efficiency by the produced biochars was tested, reaching 95% methylene blue adsorption capacity for the biochars produced with the least severe torrefaction conditions.Co-torrefaction of microalgae and lignocellulosic biomass was evaluated as a method to process microalgae sludge produced from various effluents and to obtain biochars with suitable properties for energy or material valorization. The influence of four independent variables on biochar yield and properties was evaluated by a set of experiments defined by response surface methodology (RSM). The biochars were characterized for proximate and ultimate composition, HHV, and methylene blue adsorption capacity. HHV of the biochars was positively correlated with carbonization temperature, residence time, and lignocellulosic biomass content in the feed. Co-torrefaction conditions that led to a higher yield of biochar (76.5%) with good calorific value (17.4 MJ Kg(-1)) were 250 & DEG;C, 60 min of residence time, 5% feed moisture, and 50% lignocellulosic biomass. The energy efficiency of the process was higher for lower temperatures (92.6%) but decreased abruptly with the increase of the moisture content of the feed mixture (16.9 to 57.3% for 70% moisture). Biochars produced using algal biomass grown in contaminated effluents presented high ash content and low calorific value. Dye removal efficiency by the produced biochars was tested, reaching 95% methylene blue adsorption capacity for the biochars produced with the least severe torrefaction conditions.
- Performance indicators: quantification of market performance: Deliverable D5.1Publication . Couto, António; Schimeczek, Christoph; Morales-España, Germán; Strbac, Goran; Algarvio, Hugo; Sanchez, Ingrid; Kochems, Johannes; Nienhaus, Kristina; Vries, Laurens de; Helistö, Niina; Chrysanthopoulos, Nikolaos; Hernandez-Serna, Ricardo; Johanndeiter, Silke; Pinto, Tiago; Estanqueiro, AnaABSTRACT: The present deliverable was developed as part of the research activities of the TradeRES project Task 5.1 – Performance indicators: quantification of market performance. This report presents the first version of the deliverable 5.1, which provides a list of the (key) market performance indicators (MPIs) that will be used to assess the impact of elec tricity market designs developed and tested in the TradeRES project. In specific, these indicators will be used in the case studies to assess and quantify the performance of the market designs that were developed in WP3. The foreseen recommendations regarding the evolution of the market design considering a ~100% renewable power system and the dissemination activities will also focus on the performance obtained for the different MPIs. As a first step to defining the TradeRES’ MPIs, internal information was analysed, namely, the objectives and the research questions addressed by the project. To complement this information, several ongoing and completed European projects have been reviewed. For the definition of MPIs, a template was created. The template comprises basic information such as the name and acronym of the MPI, its calculation methodology and optimal value. A total of 48 MPIs were identified, and all were classified into four different group domains identified: technical, economic, environmental and social. The goal of such classification is to facilitate filtering and finding the MPIs of particular interest for the reader.
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