Percorrer por data de Publicação, começado por "2026-01"
A mostrar 1 - 4 de 4
Resultados por página
Opções de ordenação
- Identification of saline areas in wetlands using spectral indices and geochemical data. The case of Baixo Vouga Lagunar (Aveiro, Portugal)Publication . Rolo, R. S. V.; Silva, S. M. L.; Medina, Jorge; Patinha, CarlaABSTRACT: The Baixo Vouga Lagoon (BVL) is an important wetland on the Portuguese coastal continent that has been suffering from the destruction of its agricultural fields due to saline intrusion processes. The aim of the research was to identify areas of salinity combining geochemical data and spectral indices obtained from Sentinel 2B satellite images. The methodology was developed using images from July 2023 and February 2024, with samples taken during the same seasonal period. Fourteen spectral indices were calculated: four vegetation indices and ten salinity indices. Pearson's method was used to assess the correlation between geochemical data and the spectral indices. The Canopy Response Salinity Index (CRSI) and Salinity Index 1 (SI 1) showed the highest correlation, at 0.428 and 0.516 respectively. Despite the limitations of using optical sensor in flooded areas, the spectral response of halophyte vegetation in areas of higher salinity was crucial for its differentiation and primary delimitation of the most affected areas.
- Applicability Assessment of a Microbial Proteolytic Fermentation Broth to Leather Processing and Protein Stain RemovalPublication . Lageiro, Maria Manuela; Moura, Maria João; Simões, Fernanda; Alvarenga, Nuno; Reis, AlbertoABSTRACT: Microbial proteases are fundamental towards the eco-sustainability of proteolysis at the industrial scale. A proteolytic broth was obtained from a bioreactor fermentation of a proteolytic Bacillus strain isolated from an industrial alkaline bath. Broth proteolytic activity was applied to leather tanning and to the removal of protein stains. The hide tanned with the microbial proteolytic fermentation broth showed better physical properties than the one tanned with commercial pancreatic proteases of the same activity (780 LVU). Proteinaceous stains on cotton fabric were removed more efficiently using the Bacillus proteolytic broth than water or a commercial detergent. Blood and egg yolk disappeared in less than 30 min. The removal of soya and English sauce stains was even faster. Broth proteolytic activity was characterised by caseinolytic (5200 LVU), collagenolytic (10.0 U mg-1), elastolytic (3.7 U mg-1), and keratinolytic (0.7 U mg-1) activities, which were compared with those of a commonly used commercial protease. Alkaline protease activity in the broth was demonstrated by a 20% increase in caseinolytic activity from pH 5 to 8. Besides the demonstrated applications in the leather and detergent industries, the produced alkaline microbial proteases can also be used in the treatment of proteinaceous wastes and effluents, offering potential environmental benefits reinforcing and impacting the bioeconomy.
- Unit Sizing and Feasibility Analysis of Green Hydrogen Storage Utilizing Excess Energy for Energy IslandsPublication . Koca, Kemal; Dursun, Erkan; Bekçi, Eyüp; Uçar, Suat; AKPOLAT, Alper Nabi; Tsami, Maria; Simões, Teresa; Tesch, Luana; AKSÖZ, Ahmet; Borg, Ruben PaulABSTRACT: This study examines whether green hydrogen production using combined wind and solar energy on Marmara Island can meet the island's electricity demand and fuel the fuel needs of a hydrogen-powered ferry. A hybrid system consisting of a 10 MW wind farm, a 3 MW solar PV system, and a PEM electrolyzer sized to meet the island's hydrogen demand was modeled for the island, located in the southwestern Sea of Marmara. The hydrogen production potential, energy flows, and techno-economic performance were evaluated using HOMER-Pro 3.18.4 version. According to the simulation results, the hybrid system generates approximately 62.6 GWh of electricity annually, achieving an 82.8% renewable energy share. A significant portion of the produced energy is transferred to the electrolyzer, producing approximately 729 tons of green hydrogen annually. The economic analysis demonstrates that the system is financially viable, with a net present cost of USD 61.53 million and a levelized energy cost of USD 0.175/kWh. Additionally, the design has the potential to reduce approximately 2637 tons of CO2 emissions over a 25-year period. The results demonstrate that integrating renewable energy sources with hydrogen production can provide a cost-effective and low-carbon solution for isolated communities such as islands, strengthening energy independence and supporting sustainable transportation options. It has been demonstrated that hydrogen produced by PEM electrolyzers powered by excess energy from the hybrid system could provide a reliable fuel source for hydrogen-fueled ferries operating between Marmara Island and the mainland. Overall, the findings indicate that pairing renewable energy generation with hydrogen production offers a realistic pathway for islands seeking cleaner transportation options and greater energy independence.
- Palynological insights into the Eocene-Oligocene biostratigraphy , palaeoenvironment, and palaeoclimates of the Kwanza Basin, AngolaPublication . Pereira, Zélia; Silva Mendes, Márcia Cristina; Rodrigues, Cristina F.A.; Nsungani, P.C.ABSTRACT: New biostratigraphic and palaeoenvironmental data from Cabo de Sao Bras in the Kwanza Basin reveal over 40 m of marine sediments (Cunga and Quifangondo formations) spanning the Eocene-Oligocene transition. Wellpreserved dinoflagellate cysts within these sediments provide precise age determinations and palaeoenvironmental insights. The Cunga Formation, ranging from the late Eocene to the Oligocene, is characterized by sporadic occurrences of Diphyes colligerum, Glaphyrocysta semitecta, Schematophora cf. speciosa, Deflandrea heterophlycta, Rhombodinium draco, and Rhombodinium porosum. The overlying interval reveals a Rupelian assemblage, including Achomosphaera alcicornu and Hystrichokolpoma cf. Pseudooceanicum. The uppermost part of the Cunga Formation is marked by the lowest occurrence of Tuberculodinium vancampoae and the highest occurrence of Achomosphaera alcicornu during the Chattian. In contrast to existing geological maps, the transition to the Quifangondo Formation reveals a continuous sequence from the uppermost Chattian, based on the cooccurrence of Distatodinium paradoxum and Phelodinium africanum, along with a significant acme of Hystrichokolpoma spp. Palaeoenvironmental analysis suggests a marine setting with periods of both low and high productivity. Significant environmental transitions are observed, ranging from outer neritic to oceanic conditions at the base of the Cunga Formation (late Eocene-Oligocene, late Rupelian-early Chattian). In the late Oligocene, despite considerable terrigenous input, palynological data suggest predominantly inner to outer neritic conditions at the top of the Cunga Formation and the base of the Quifangondo Formation. Fluctuations in dinoflagellate cyst influxes reflect changes in water temperatures, providing insights into past climate shifts, during the EoceneOligocene transition, and offering a valuable framework for future palaeoclimatic investigations.