Percorrer por autor "Geraldes, V."
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- Control of predators in industrial scale microalgae cultures with Pulsed Electric Fields.Publication . Rego, D.; Luis Redondo; Geraldes, V.; Costa, Luiz; Navalho, J.; Pereira, Marcos TeotónioThis work describes the utilization of Pulsed Electric Fields to control the protozoan contamination of a microalgae culture, in an industrial 2.7m3 microalgae photobioreactor. The contaminated culture was treated with Pulsed Electric Fields, PEF, for 6h with an average of 900V/cm, 65μs pulses of 50Hz. Working with recirculation, all the culture was uniformly exposed to the PEF throughout the assay. The development of the microalgae and protozoan populations was followed and the results showed that PEF is effective on the selective elimination of protozoa from microalgae cultures, inflicting on the protozoa growth halt, death or cell rupture, without affecting microalgae productivity. Specifically, the results show a reduction of the active protozoan population of 87% after 6h treatment and 100% after few days of normal cultivation regime. At the same time, microalgae growth rate remained unaffected. © 2014 Elsevier B.V.
- Environmental sleep disruptors: the role of thermal comfort and CO2 levelsPublication . Belo, Joana; Gonçalves, Sara; Mendez, S.; Bartolomeu, S.; Bárbara, P.; Meira-Cruz, M.; Geraldes, V.; Almeida-Silva, Marina; Carolino, Elisabete; Lage, JoanaIntroduction: Sleep is a vital physiological process essential for physical recovery, cognitive function, and emotional balance. Its quality is influenced not only by individual and behavioral factors but also by environmental conditions in the sleep setting. Among these, thermal comfort and indoor air quality, particularly ambient temperature and carbon dioxide (CO2) concentration, are increasingly recognized as important modulators of sleep architecture and continuity. Suboptimal thermal conditions and elevated CO2 levels may impair sleep efficiency, reduce total sleep time, and increase the frequency of nocturnal awakenings. This study presents preliminary data from the HypnosAir Project (www.hypnosair.com), which investigates the impact of indoor environmental conditions on sleep quality.
- Impact of nocturnal air pollution on sleep quality and emergency health service utilization for respiratory and cardiovascular conditions in Portugal: an ecological analysis using open dataPublication . Meira e Cruz, M.; Geraldes, V.; Rocha, I.; Belo, Joana; Lage, Joana; Winck, J.Introduction: Poor air quality is a recognized risk factor for respiratory and cardiovascular diseases. Nocturnal exposure to air pollutants may further impair sleep quality, compounding health risks and increasing emergency healthcare utilization. The interplay between nighttime environmental stressors and sleep disruption remains underexplored in the Portuguese context. With this work, the authors aimed to examine the association between nocturnal air pollution, sleep quality indicators, and emergency department visits for respiratory and cardiovascular complaints across multiple regions in Portugal.
- Nanofiltration of Cork Wastewaters and Their Possible Use in Leather Industry as Tanning AgentsPublication . Geraldes, V.; Minhalma, Miguel; de Pinho, M. N.; Anil, A.; Ozgunay, H.; Bitlisli, B. O.; Sari, O.Cork processing wastewater is a very complex mixture of vegetal extracts and has, among other natural compounds, a very high content of phenolic/tannic colloidal matter that is responsible for severe environmental problems. In the present work, the concentration of this wastewater by nanofiltration was investigated with the aim of producing a cork tannin concentrate to be utilized in tanning. Permeation results showed that the permeate fluxes are controlled by both osmotic pressure and fouling/gel layer phenomena, leading to a rapid decrease of permeate fluxes with the concentration factor. The rejection coefficients to organic matter were higher than 95%, indicating that nanofiltration has a very good ability to concentrate the tannins and produce a permeate stream depleted from organic matter. The cork tannin concentrate obtained by nanofiltration and evaporation had total solids concentration of 34.8 g/l. The skins tanned by this concentrate were effectively converted to leather with a shrinking temperature of 7 degrees C.