Lebanon: between aspiration of changes and the ancient regime

The Syrian refugee crisis, the 2019 riots, the 2020 Beirut port explosion, a deep institutional and financial crisis. In these last years Lebanon and Lebanese experienced extraordinary events which hugely aected both people and institutions. This report is exploring all these crisis dimensions with the aim of providing “food for thought” and contribute to the debate related to the immediate future of the country and therole that youth can eventually play. Thanks to the collaboration with Lebanese academicians and a well-structured field research performed in the country, authors have been able to present an unusual point of view with respect to some crucial issues that are affecting nowadays Lebanon: the resilience of the sectarian system, youths' aspirations for the future, new parties and movements aims and objectives and the “old regime” perspectives. This report represents a unique “document” containing unprecedent testimonies. A “document” which will be hopefully upscaled by other academicians for their future research; a first step towards the comprehension of complex phenomena that will interest Lebanon institutions and Lebanese lives in the forthcoming years. As no final answer is ready yet, it is necessary to continue to research for it and stimulate debate around urgent and critical issues. “Leaving” (Irhal) cannot be the only solution both for corrupt politicians neither for Lebanese youths

Sound absorption by perforated walls along boundaries

We analyze the Helmholtz equation in a complex domain. A sound absorbing structure at a part of the boundary is modelled by a periodic geometry with periodicity ε > 0. A resonator volume of thickness ε is connected with thin channels (opening ε^3) with the main part of the macroscopic domain. For this problem with three different scales we analyze solutions in the limit ε → 0 and find that the effective system can describe sound absorption

The periodic unfolding method in domains with holes

We give a comprehensive presentation of the periodic unfolding method for perforated domains, both when the unit hole is a compact subset of the open unit cell and when this is impossible to achieve. In order to apply the method to boundary-value problems with non homogeneous Neumann conditions on the boundaries of the holes, the properties of the boundary unfolding operator are also extensively studied. The paper concludes with applications to such problems and examples of reiterated unfolding

Effect of leaf removal and ripening stage on the content of quercetin glycosides in Sangiovese grapes

Quercetin haze has been observed over the last few years in some aged Sangiovese wines. This problem could be due to an excess of the quercetin in the wine. Leaf removal increases the exposition of clusters to sunlight, which may enhance flavonol synthesis in the grapes. In this study, we evaluated the dynamics related to extractable flavonols in grapes grown in three usually defoliated Vitis vinifera (L.) cv. Sangiovese vineyards, whose wines showed quercetin precipitates. The particular structure of the vineyards in which the leaf removal experiments were carried out allowed the influence of vineyard, biotype and rootstock on grape flavonol contents at mid-maturation and technological maturity to be evaluated. The leaves were removed at pre-flowering (early) and at veraison (late). Leaf removal increased the content of extractable glycosidic flavonols in grapes at the two tested ripening stages. In addition, vineyard, biotype and rootstock affected the content of glycosidic flavonols and the interaction between the studied variables was significant. Even though leaf removal induced an increase in extractable quercetin glycosides which can increase the risk of quercetin haze in wine, an examination of the scientific literature on this topic showed that this risk does not depend on the absolute content of these compounds alone

Solubility of Quercetin in Wines

Quercetin solubility at 18 °C and 0 °C was determined in an hydroalcoholic buffer solution with pH 3.20 and in four Italian wines to study the formation of quercetin precipitate mechanism in wines. The wines selected were Barbera 2018 for the typically high content in bisulfite bleachable pigments, red Cirò 2014, for its typically high content of flavonoids, Sangiovese 2014, for the presence of quercetin deposits in bottle, and white Cirò 2018, for the absence of red pigments. All the samples were spiked with 30 mg/L quercetin. The amount of quercetin solubilized at 18 °C and 0 °C in the hydroalcoholic buffer was much lower than in wines, while that solubilised in Barbera was much higher compared to red Cirò, Sangiovese and white Cirò. Solubilised quercetin was lower in all wine samples stored at 0 °C than in those at 18 °C. The pigment composition of the three red wines examined suggested that the over-solubility of quercetin could be due to the formation of soluble co-pigmentation complexes between quercetin and monomer anthocyanins and/or bisulphate-bleachable flavanol-anthocyanin pigments. A positive correlation between quercetin solubility and bleachable pigment was noted: the richer the wine in bleachable pigments, the higher the solubility of quercetin. Quercetin haze formation appeared due to the release of quercetin from co-pigmentation complexes during wine maturation and storage ,as its counterpart, anthocyanins, form non-bleachable pigments or are degraded in hydrolytic or oxidation reactions. Quercetin in aged red wines seemed to reach a content similar to that of white wine spiked with quercetin. Nevertheless, the quercetin content of aged red wines in which a quercetin haze has been found could be lower than that when added white wine, due to its degradation probably being induced by oxidation reactions. Finally, the solubilized quercetin content in white Cirò, which was higher than the hydroalcoholic buffer solution, suggested that there may be different substances in wines than pigments that prevent the growth of quercetin crystals. However, their nature was not determined in this study

Solubility of Quercetin in Wines

Quercetin solubility at 18°C and 0°C was determined in a hydroalcoholic buffer solution with a pH of 3.20 and in four Italian wines to study the formation mechanism of quercetin precipitate in wines. The wines selected were Barbera 2018, for its typically high content of bisulphite bleachable pigments, red Cirò 2014, for its typically high content of flavonoids, Sangiovese 2014, for the presence of quercetin deposits in the bottle, and white Cirò 2018, for the absence of red pigments. All the samples were spiked with 30 mg/L quercetin. The amount of quercetin solubilised at 18°C and 0°C in the hydroalcoholic buffer was much lower than in the wines, while that solubilised in Barbera was much higher compared to red Cirò, Sangiovese and white Cirò. Solubilised quercetin was lower in all wine samples stored at 0°C than in those stored at 18°C. The pigment composition of the three red wines examined suggests that the over-solubility of quercetin could be due to the formation of soluble co-pigmentation complexes between quercetin and monomer anthocyanins and/or bisulphate-bleachable flavanol-anthocyanin pigments. A positive correlation between quercetin solubility and bleachable pigment was noted: the richer the wine in bleachable pigments, the higher the solubility of quercetin. Quercetin haze formation appeared due to the release of quercetin from co-pigmentation complexes during wine maturation and storage, as its counterpart, anthocyanins, form non-bleachable pigments or are degraded in hydrolytic or oxidation reactions. Quercetin in aged red wines seems to reach a content similar to that of white wine spiked with quercetin. Nevertheless, the quercetin content of aged red wines in which a quercetin haze has been found could be lower than that when added to white wine, due to its degradation probably being induced by oxidation reactions. Finally, the solubilised quercetin content in white Cirò, which was higher than the hydroalcoholic buffer solution, suggests that there may be different substances in wines than pigments that prevent the growth of quercetin crystals. However, their nature was not determined in this study

Strategies and Techniques for Powering Wireless Sensor Nodes through Energy Harvesting and Wireless Power Transfer

The continuous development of the internet of things (IoT) infrastructure and applications is paving the way for advanced and innovative ideas and solutions, some of which are pushing the limits of state-of-the-art technology. The increasing demand for Wireless Sensor Nodes (WSNs) able to collect and transmit data through wireless communication channels, while often positioned in locations that are difficult to access, is driving research into innovative solutions involving energy harvesting (EH) and wireless power transfer (WPT) to eventually allow battery-free sensor nodes. Due to the pervasiveness of radio frequency (RF) energy, RF EH and WPT are key technologies with the potential to power IoT devices and smart sensing architectures involving nodes that need to be wireless, maintenance free, and sufficiently low in cost to promote their use almost anywhere. This paper presents a state-of-the-art, ultra-low power 2.5 W highly integrated mixed-signal system on chip (SoC), for multi-source energy harvesting and wireless power transfer. It introduces a novel architecture that integrates an ultra-low power intelligent power management, an RF to DC converter with very low power sensitivity and high power conversion efficiency (PCE), an Amplitude-Shift-Keying/Frequency-Shift-Keying (ASK/FSK) receiver and digital circuitry to achieve the advantage to cope, in a versatile way and with minimal use of external components, with the wide variety of energy sources and use cases. Diverse methods for powering wireless Sensor Nodes through energy harvesting and wireless power transfer are implemented providing related system architectures and experimental results