Comparison of fundamental positive-sequence detectors for highly distorted and unbalanced systems

This paper presents a performance comparison between a PLL and an Adaptive Filter for detecting the positive sequence at the fundamental frequency of any given voltage or current signals of a three-phase system. The comparative analysis was based on the evaluation of a series of steady state performance parameters (phase and amplitude errors, THD and unbalance) and on the response time. The tests were made to study the behaviour of both approaches when working with highly distorted and unbalanced signals. This work was carried out using the computer simulation tool PSCAD/EMTDC.The authors are grateful to FCT (Fundação para a Ciência e a Tecnologia), project funding POCTI/ESE/41170/2001

Thermal performance and comfort condition analysis in a vernacular building with a glazed balcony

The increase in global environmental problems requires more environmentally efficient construction. Vernacular passive strategies can play an important role in helping reducing energy use and CO2 emissions related to buildings. This paper studies the use of glazed balconies in the North of Portugal as a strategy to capture solar gains and reduce heat losses. The purpose is understanding thermal performance and comfort conditions provided by this passive heating strategy. The methodology includes objective (short and long-term monitoring), to evaluate the different parameters affecting thermal comfort and air quality, and subjective assessments to assess occupants? perception regarding thermal sensation. The results show that the use of glazed balconies as a passive heating strategy in a climate with cold winters is viable. During the mid-seasons, the rooms with balcony have adequate comfort conditions. In the heating season, it is possible to achieve comfort conditions in sunny days while in the cooling season there is a risk of overheating. Regarding indoor air quality, carbon dioxide concentrations were low, but the average radon concentration measured was high when the building was unoccupied, rapidly decreasing to acceptable values, during occupation periods when a minimum ventilation rate was promoted. Occupants? actions were essential to improving building behavior.The authors would like to acknowledge the support granted by the FEDER funds through the Competitively and Internationalization Operational Programme (POCI) and by national funds through FCT (Foundation for Science and Technology) within the scope of the project with the reference POCI-01-0145-FEDER-029328, and of the Ph.D. grant with the reference PD/BD/113641/2015, that were fundamental for the development of this study

Impact of atomic layer deposited TiO2 on the photocatalytic efficiency of TiO2/w-VA-CNT nanocomposite materials

Titanium oxide (TiO2) has been widely investigated as a photocatalytic material, and the fact that its performance depends on its crystalline structure motivates further research on the relationship between preparation methods and material properties. In this work, TiO2 thin films were grown on non- functionalized wave-like patterned vertically aligned carbon nanotubes (w-VA-CNTs) via the atomic layer deposition (ALD) technique. Grazing incidence X-ray diffraction (GIXRD) analysis revealed that the structure of the TiO2/VA-CNT nanocomposites varied from amorphous to a crystalline phase with increasing deposition temperature, suggesting a “critical deposition temperature” for the anatase crystalline phase formation. On the other hand, scanning transmission electron microscopy (STEM) studies revealed that the non-functionalized carbon nanotubes were conformally and homogeneously coated with TiO2, forming a nanocomposite while preserving the morphology of the nanotubes. X-ray photoelectron spectroscopy (XPS) provided information about the surface chemistry and stoichiometry of TiO2. The photodegradation experiments under ultraviolet (UV) light on a model pollutant (Rhodamine B, RhB) revealed that the nanocomposite comprised of anatase crystalline TiO2 grown at 200 ?C (11.2 nm thickness) presented the highest degradation efficiency viz 55% with an illumination time of 240 min. Furthermore, its recyclability was also demonstrated for multiple cycles, showing good recovery and potential for practical applications.publishe

Nanoencapsulation of quercetin into bio-based nanostructures obtained from assembling of α-lactalbumin and lysozyme

Nanotechnology possesses an intrinsic potential to produce new food ingredients and innovative products, with considerable benefits to human health. This can be attained via development of innovative structures for application in functional foods. In recent years, consumption of foods providing health benefits has risen chiefly as a result of significant investments from the food industry and widening consumer awareness in this field. Polyphenols constitute one such functional ingredient: it entails a large group of plant metabolites with a large spectrum of recognized biological activities in humans. Quercetin is, in particular, one of the most representative compounds of the flavonoid family; it has been assigned a wide range of health benefits, including anti-inflammatory agent, cancer prevention, DNA protection agent, antioxidant and cardio-protective agent. However, its bioavailability is low, so limited biological effects may be noticed arising from its poor solubility, gastrointestinal instability and low uptake rate through the gastrointestinal tract. A possible solution to overcome such limitations is nanoencapsulation of quercetin. Therefore, our study was aimed at encapsulating quercetin into bio-based nanostructures obtained from assembling of α-lactalbumin (α-La) and lysozyme (Lys), as promoted by heating at 75 oC for 15 min, at pH 11; evaluation of their association efficiency was performed. Such nanostructures were prepared via solubilization of 2 mg mL-1 of Lys and α-La powders in water, at a molar ratio of 1:0.54, and were extensively characterized by dynamic light scattering (for particle size, polydispersity and zeta potential) and transmission electron microscopy (for microstructure and morphology). Quercetin has been successfully encapsulated into protein nanostructures above 50% efficiency. These nanostructures exhibited spherical morphology, with average size below 100 nm and zeta potential around -35 mV. Our results suggest that quercetin encapsulated in such proteinaceous nanostructures may be used for manufacture of functional foods

Comparison between semi-intensively and intensively grown beef

info:eu-repo/semantics/publishedVersio

New records of Ticapimpla Gauld, 1991 (Hymenoptera: Ichneumonidae: Pimplinae) from Brazil and French Guiana, with taxonomic notes

Background We report the genus Ticapimpla Gauld, 1991 from French Guiana and the species Ticapimpla amazonica Palacio et al., T. carinata Palacio et al., T. matamatae Palacio et al. and T. soinii Palacio et al. from Brazilian Amazonia. The new discoveries suggest that the genus is widely distributed in Amazonian lowland rain forests. In addition, we diagnose and illustrate the males of T. carinata and T. matamatae for the first time. Short diagnoses and layer-photos for all the Amazonian species are provided.New informationThe genus Ticapimpla is reported for the first time from French Guiana and the species T. amazonica, T. carinata, T. matamatae and T. soinii from Brazilian Amazonia. In addition, the males of T. carinata and T. matamatae are diagnosed and illustrated for the first time.</p

Lanthanide-based complexes as efficient physiological temperature sensors

A new molecular thermometric sensor based on the terbium(III) complex [C2mim][Tb(fod)4] (C2mim – 1-methyl-3-ethylimidazolium, fod− - tetrakis-6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionate), doped with 0.015% of its europium(III) analogue (1, [C2mim][Tb(fod)4]0.99985:[C2mim][Eu(fod)4]0.00015), was prepared and its thermochromic behaviour evaluated from ambient temperature up to 75 °C, including in the physiological range (35–45 °C). It was found that the intensity ratio of the 5D4→7F5 (TbIII) and 5D0→7F2 (EuIII) transitions is correlated with temperature having three different linear regimes. Visual colorimetry allowed the evaluation of the temperature in different ranges from green at ambient temperature, to yellow and finally red at higher temperatures. The TbIII complex emission intensity is extremely sensitive to small temperature variations, particularly between 25 and 35 °C, were it reaches only 40% of the initial intensity. Confinement of the dopped TbIII tetrakis-complex in the organic polymeric matrix poly(methylmethacrylate) (PMMA) induced higher thermal stability in 1, together with a strong temperature dependence of the most intense emissive transition of the TbIII complexes. The photoluminescence quantum yield of polymer-lanthanide hybrid materials increased significantly compared with that of 1. Under 366 nm irradiation, the hybrid material presents a green colour at 25 °C that evolves to yellow at 30 °C and to a white tone at 35 °C.publishe

Spatiotemporal variability of dissolved inorganic macronutrients along the northern Antarctic Peninsula (1996–2019)

The northern Antarctic Peninsula is a key region of the Southern Ocean due to its complex ocean dynamics, distinct water mass sources, and the climate-driven changes taking place in the region. Despite the importance of macronutrients in supporting strong biological carbon uptake and storage, little is known about their spatiotemporal variability along the northern Antarctic Peninsula. Hence, we explored for the first time a 24-year time series (1996–2019) in this region to understand the processes involved in the spatial and interannual variability of macronutrients. We found high macronutrient concentrations, even in surface waters and during strong phytoplankton blooms. Minimum concentrations of dissolved inorganic nitrogen (DIN; 16 μmol kg−1), phosphate (0.7 μmol kg−1), and silicic acid (40 μmol kg−1) in surface waters are higher than those recorded in surrounding regions. The main source of macronutrients is the intrusions of Circumpolar Deep Water and its modified variety, while local sources (organic matter remineralization, water mass mixing, and mesoscale structures) can enhance their spatiotemporal variability. However, we identified a depletion in silicic acid due to the influence of Dense Shelf Water from the Weddell Sea. Macronutrient concentrations show substantial interannual variability driven by the balance between the intrusions of modified Circumpolar Deep Water and advection of Dense Shelf Water, which is largely modulated by the Southern Annular Mode (SAM) and to some extent by El Niño-Southern Oscillation (ENSO). These findings are critical to improving our understanding of the natural variability of this Southern Ocean ecosystem and how it is responding to climate changes