Browsing by Issue Date, starting with "2022-02"
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- Potentially toxic elements dynamics in the soil rhizospheric-plant system in the active volcano of Fogo (Cape Verde) and interactions with human healthPublication . Candeias, Carla; Ávila, Paula Freire; Sequeira, Cristina; Albuquerque, Manuel; Rocha, FernandoABSTRACT: Volcanic eruptions disturb directly and indirectly the ecosystems. Direct impact occurs on the soil-plant system with an input of new elements and indirect hazard occurs by consumption of these plants. Fogo island (Cape Verde Republic) has an active volcano and the last eruption occurred in 2014-15, expelling large amounts of materials that spread all over the island. Soils and edible plants were collected all over the island. Pollution indexes reveal contamination in all samples, mostly due to Hg and Ni and with moderate contribution of Co, Cr, Cu and Pb. Mercury is the PTE with higher contribution to the non-carcinogenic hazard quotient, both by soil ingestion and inhalation. Carcinogenic risk exceeds the target risk in all samples with the higher contribution of Ni. Transfer factor from soils to plants decreasing order is Mn > As > Zn > Cr > Cu > Cd > Pb > Ni > Co > Hg, being < 1 except for As and Mn (TF > 1 point to a significant accumulation of elements in edible plants). The hazard risk index and targeted hazard quotient shows that potential negative health outcomes can be induced by As, Cr, Cu, and Zn by consumption of edible plants.
- Nannochloropsis oceanica biomass enriched by electrocoagulation harvesting with promising agricultural applicationsPublication . Figueiredo, Daniel; Ferreira, Alice; Gama, Florinda; Gouveia, LuisaABSTRACT: Electrocoagulation is a promising technology to harvest and concentrate microalgae while saving costs on secondary dewatering steps. However, the sacrificial electrodes release salts that impact the media and the harvested biomass. This study evaluated the effects of Fe, Zn, and Mg electrodes on Nannochloropsis oceanica harvesting and elementary composition of biomass and supernatants. Moreover, plant bioavailability of electrocoagulation minerals attached to biomass was assessed in the tomato plant model Solanum lycopersicum (cv. ‘Cherry’). Fe electrodes had better performance at lower power consumption and operation costs, followed by Zn and Mg. Electrocoagulation changes biomass and supernatant nutrient composition. Electrodes precipitated Mg and Ca from the nutrient media, enriching N. oceanica biomass, but increased Pb 2–4 times and depleted P in supernatants. Finally, Fe and Mg electrode metals in the biomass were proven bioavailable to S. lycopersicum seedlings, making electrocoagulation harvested biomass a promising bioresource to agricultural applications.
- Robust relation between public procurement for innovation and economic developmentPublication . Bento, Nuno; Sousa, Cristina; Trindade, Paula; Mamede, Ricardo Paes; Fontes, Margarida; Alves, TiagoABSTRACT: We found a solid and robust relationship between the share of public procurement for innovation (PPI) in public procurement and GDP per capita for 30 European countries. The share of PPI is highly associated with determinants from ‘‘demand pull’’ as well as ‘‘supply push’’. These findings open new opportunities for the study of the drivers of public procurement for innovation. The study also provides a new methodology for benchmarking.
- Rhodosporidium toruloides and Tetradesmus obliquus Populations Dynamics in Symbiotic Cultures, Developed in Brewery Wastewater, for Lipid ProductionPublication . Dias, Carla; Gouveia, Luisa; Santos, J. A. L.; Reis, Alberto; Silva, Teresa Lopes daABSTRACT: In this work, primary brewery wastewater (PBWW) and secondary brewery wastewater (SBWW) separately, or mixed at the ratios of 1:1 (PBWW:SBWW) and 1:7 (PBWW:SBWW), with or without supplementation with sugarcane molasses (SCM), were used as culture media for lipid production by a mixed culture of the oleaginous yeast Rhodosporidium toruloides NCYC 921 and the microalgae Tetradesmus obliquus (ACOI 204/07). Flow cytometry was used to understand the dynamics of the two micro-organisms during the mixed cultures evolution, as well as to evaluate the physiological states of each microorganism, in order to assess the impact of the different brewery effluent media composition on the microbial consortium performance. Both brewery wastewaters (primary and secondary) without supplementation did not allow R. toruloides heterotrophic growth. Nevertheless, all brewery wastewater media, with and without SCM supplementation, allowed the microalgae growth, although the yeast was the dominant population. The maximum total biomass concentration of 2.17 g L-1 was achieved in the PBWW mixed cultivation with 10 g L-1 of SCM. The maximum lipid content (14.86% (w/w DCW)) was obtained for the mixed culture developed on SBWW supplemented with 10 g L-1 of SCM. This work demonstrated the potential of using brewery wastewater supplemented with SCM as a low-cost culture medium to grow R. toruloides and T. obliquus in a mixed culture for brewery wastewater treatment with concomitant lipid production.
- Palynological addendum report of sesmarias and caveira drillingPublication . Pereira, Zélia; Mendes, Márcia
- An insight into the firing conditions of Chinese blue-and-white porcelain through XANESPublication . Coutinho, ML; Veiga, JP; Ruivo, Andreia; Silva, Teresa; Salas-Colera, Eduardo; Bottura Scardina, Silvia; Lima, Augusta; Figueiredo, Elin; Cotte, Marine; Lima, M.M.R.A.ABSTRACT: Chinese blue-and-white porcelain is found in archaeological excavations worldwide, being significant evidence of global trade routes and cultural exchange. Synchrotron radiation-based techniques have been applied for studying cobalt speciation to establish a correlation between the cobalt and iron oxidation state and local coordination environment in the rich blue shades of Chinese blue-and-white porcelain. However, the relationship between the firing atmosphere conditions and the speciation of cobalt has not been established yet. In this study, underglaze blue models were produced and fired in air or under reducing atmospheres to ascertain the effect of the firing atmosphere in cobalt and iron speciation. The experimental results were compared with data obtained on historical samples of ancient porcelain shards. The microstructure and colour of the produced underglaze blue models were investigated by variable pressure scanning electron microscopy (VP-SEM-EDS), using a hyperspectral imaging camera (Vis-SWIR reflectance spectroscopy) and colorimetry. The formal valence and coordination of cobalt and iron ions of the glaze were determined by X-ray absorption spectroscopy (XAS), particularly X-ray absorption near edge structure (XANES), using synchrotron radiation. Spectral features demonstrated that both cobalt and iron speciation were affected by the firing atmosphere and therefore could be used to ascertain the firing atmosphere.
- Primary brewery wastewater as feedstock for the yeast Rhodosporidium toruloides and the microalga Tetradesmus obliquus mixed cultures with lipid productionPublication . Dias, Carla; Reis, Alberto; Santos, J. A. L.; Gouveia, Luisa; Silva, Teresa Lopes daABSTRACT: Rhodosporidium toruloides and Tetradesmus obliquus pure and mixed cultures were grown on primary brewery wastewater (PBWW), with and without supplementation of sugarcane molasses (SCM) and urea. R. toruloides developed in pure cultures was not able to grow on PBWW, with or without supplementation, but grew in mixed cultures with the micmalga T. obliquus in all media. In contrast, all T. obliquus pure cultures developed on PBWW, with and without supplementation, were able to develop. Higher biomass productivity (149.3 mg L-1 h(-1)) was obtained for the mixed culture using PBWW supplemented with 10 g L-1 of SCM and 2 g L-1 of urea. Therefore, a strategy to stimulate lipid production by R. toruloides and T. obliquus grown in mixed cultures with higher SCM concentrations (20, 40 and 100 g L-1 of SCM) was developed. The maximum lipid content (26.3 % (w/w DCW)) was obtained for the mixed culture developed on PBWW, supplemented with 100 g L-1 of SCM plus 2 g L-1 of urea, at t = 121 h. This work demonstrated the feasibility of using PBWW supplemented with SCM and urea as culture medium to grow R. toruloides and T. obliquus and to produce microbial lipids.
- Improvement of Mechanical Properties with Non-Equimolar CrNbTaVW High Entropy AlloyPublication . Antão, Francisco; Martins, Ricardo; Correia, J.B.; Silva, R.C. da; Gonçalves, António Pereira; Tejado, Elena; Pastor, Jose Ygnacio; Alves, E.; Dias, MartaABSTRACT: CrNbTaVWx with (x = 1 and 1.7) high entropy alloys have been devised for thermal barriers between the plasma-facing tungsten tiles and the copper-based heat sink in the first wall of fusion nuclear reactors. These novel materials were prepared by ball milling and consolidated by Upgrade Field Assisted Sintering Technology at 1873 K under an applied pressure of 90 MPa for 10 min. In this work, the structural and mechanical properties of these materials were evaluated. Consolidated samples presented a major phase with a bcc-type structure with lattice parameter value of 0.316 nm for CrNbTaVW and CrNbTaVW1.7 compositions. Moreover, observation of the microstructures evidences also two minor phases: Ta-Nb-Cr and Ta-V rich (in which carbon is detected). Despite the similarity in the structural properties of these two alloys, their mechanical properties are distinct. The flexural stress for the sample with higher amount of W (CrNbTaVW1.7) is higher by 50% in the 298-873 K range, with an increased strain to fracture, which can be associated with reduced brittleness caused by the additional W incorporation.