https://accedacris.ulpgc.es/jspui/handle/10553/30002 Wed, 15 Apr 2026 04:58:39 GMT 2026-04-15T04:58:39Z https://accedacris.ulpgc.es/jspui/handle/10553/163224 Título: Combined CFD-EFD methods applied to determining the form factor of vessels with very low length to beam ratio Autores/as: Oyuela, S.; Díaz Ojeda, Héctor Rubén; Otero, A. D.; Sosa, R. Resumen: This study investigates the influence of scale effects on form factor determination for a fishing vessel with a low length-to-beam (L/B) ratio, using a combined Experimental Fluid Dynamics (EFD) and Computational Fluid Dynamics (CFD) approach. The research compares the behavior of the form factor between a fishing vessel and the well-known KCS benchmark hull. Results show that scale effects have a more significant impact on the fishing vessel, particularly due to increased viscous pressure losses in the stern region. While the non-dimensional frictional resistance component remains similar between both hulls, the non-dimensional pressure component differ significantly, highlighting the influence of hull shape on pressure recovery. The comparison with empirical methods reveals that traditional marine formulations may not adequately capture full scale form factor of hulls with very low length to beam ratio. Instead, the form factor obtained using aircraft drag estimation approaches shows better agreement with CFD predictions at full scale. Based on these findings, the adoption of distinct form factor values at model and full scale is recommended for vessels with similar geometric characteristics, in contrast to conventional extrapolation practices that assume a constant form factor. This methodology may improve the accuracy of effective power predictions and support more reliable design evaluations. Thu, 01 Jan 2026 00:00:00 GMT https://accedacris.ulpgc.es/jspui/handle/10553/163224 2026-01-01T00:00:00Z https://accedacris.ulpgc.es/jspui/handle/10553/163222 Título: Complementary Spanish photovoltaic and Danish offshore wind pathways to cost-competitive renewable hydrogen Autores/as: Cabrera Santana, Pedro Jesús; Sorknaes, Peter; Carta González, José Antonio; Meng, Yuan; Lund, Henrik Resumen: This paper evaluates the techno-economic feasibility of large-scale green hydrogen production and export from Spain and Denmark by optimising renewable generation, electrolyser capacity, and hydrogen storage. We develop an integrated framework that minimizes the levelized cost of hydrogen (LCOH) while considering three storage technologies: liquid organic hydrogen carriers (LOHCs), salt caverns, and pressurised tanks. The approach combines country-specific optimisation with comparative technology assessment under future deployment assumptions and dual uncertainty (techno-economic and interannual). Results show that storage technology is the dominant cost driver, outweighing location-specific renewable energy characteristics. LOHC systems and salt caverns achieve comparably low LCOH values, offering competitive solutions depending on local geological constraints. In contrast, pressurised tanks entail substantially higher costs, making them suitable only for niche or short-term applications. A key finding is the seasonal complementarity between Spanish PV and Danish offshore wind: PV peaks in spring and summer, while offshore wind provides higher output in autumn and winter. Coordinating production and storage across both countries can reduce seasonal cost swings and improve export competitiveness under the European Hydrogen Backbone initiative. The proposed framework and sensitivity analysis offer strategic insights for designing hybrid hydrogen export systems and selecting appropriate storage technologies in regions with contrasting renewable profiles. Thu, 01 Jan 2026 00:00:00 GMT https://accedacris.ulpgc.es/jspui/handle/10553/163222 2026-01-01T00:00:00Z https://accedacris.ulpgc.es/jspui/handle/10553/163217 Título: Cu (II) removal from aqueous solution and real textile wastewater: mechanistic insights, process optimization, and theoretical modeling using advanced Chitosan–EDTA beads Autores/as: Bourachdi, Soukaina El; Rakcho, Yassine; Ayub, Ali Raza; Amri, Abdelhay El; Moussaoui, Fatima; Araña, J.; Herrera-Melián, José Alberto; Abourriche, Abdelkrim; Hannache, Hassan; Lahkimi, Amal Resumen: Copper ions (Cu2⁺) are highly toxic and persistent pollutants in industrial wastewater, posing serious environmental and health risks. This study develops a sustainable chelating adsorbent based on ethylenediaminetetraacetic acid-functionalized chitosan beads (Chitosan@EDTA) for efficient Cu2⁺ removal from aqueous solutions and real textile wastewater. The material was designed by integrating EDTA chelation chemistry with chitosan bead structure. Characterization analyses confirmed successful EDTA grafting and the formation of a mesoporous network with a surface area of 8.81 m2/g and an average pore diameter of 3.19 nm, promoting ion diffusion. Batch adsorption experiments showed a high Langmuir monolayer adsorption capacity of 184.16 mg/g at pH 5 (R2 = 0.990), outperforming several conventional adsorbents. Thermodynamic analysis indicated that the adsorption process was spontaneous, endothermic, and entropy-driven. Response Surface Methodology based on Box–Behnken Design was applied to optimize operational parameters and obtain a highly accurate predictive model (R2 = 0.9996). Density Functional Theory analysis revealed enhanced chemisorption through coordination interactions between Cu2⁺ and amine and carboxylate groups, supported by reduced HOMO–LUMO energy gaps. Practical application demonstrated 98.2% Cu2⁺ removal from real textile wastewater. Overall, Chitosan@EDTA shows strong potential as an efficient and sustainable adsorbent for industrial wastewater treatment. Thu, 01 Jan 2026 00:00:00 GMT https://accedacris.ulpgc.es/jspui/handle/10553/163217 2026-01-01T00:00:00Z https://accedacris.ulpgc.es/jspui/handle/10553/163216 Título: Blue carbon inventories of Spain and Portugal for their inclusion in national climate mitigation strategies Autores/as: Pineiro-Juncal, Nerea; Serrano, Oscar; De Los Santos, Carmen B.; Marba, Nuria; Diaz-Almela, Elena; Tuya, Fernando; Mazarrasa, Ines; Garmendia, Joxe Mikel; Oteroi, Xose Lois; Inostroza, Karina; Pages, Jordi F.; Mendez-Martinez, Gonzalo; Fernandez, Emilio; Sousa, Ana I.; Camacho, Antonio; Ballesteros, Enric; Baranano, Carlota; Belshe, Fay; Bernabeu, Irene; Brun, Fernando G.; Camacho-Santamans, Alba; Delgado, Antonio; Dahl, Martin; Duarte, Carlos M.; Espino, Fernando; Franco, Javier; Freitas, Maria Da Conceicao; Garcia-Orellana, Jordi; Garrigos, Bernat; Gomis, Enric; Haroun, Ricardo; Hernandez, Ignacio; Juanes, Jose A.; Leiva-Duenas, Carmen; Lavery, Paul; Lillebo, Ana I.; Lopes, Vera; Majtenyi-Hill, Claudia; Marco-Mendez, Candela; Martins, Marcio; Monnieraa, Briac; Morant, Daniel; Montero, Natalia; Neto, Joao M.; Ondiviela, Barbara; Peralta, Gloria; Picazo, Antonio; Reithmaier, Gloria; Rochera, Carlos; Roman, Marta; Santos, Isaac R.; Santos, Rui; Serranoj, Eduard; Solerb, Montserrat; Yau, Yu Yau; Weitzmann, Boris; Zribi, Imen; Mateo, Miguel Angel Resumen: The fast changes in climate are driving global efforts to reduce greenhouse emissions and offset those that cannot be avoided. Interest in vegetated coastal ecosystems, known as Blue Carbon Ecosystems (BCEs), has grown rapidly due to their potential contribution to global carbon sequestration. Spain and Portugal host two of the main BCEs types; seagrass meadows and tidal marshes. To date, no comprehensive national assessment of BCEs carbon stocks has been conducted for Spain and Portugal. We have assessed the magnitude of the carbon sink associated with them across the entire Iberian Peninsula and insular Spanish territories and the potential CO2 emission resulting from their degradation. The BCEs in the studied area are estimated to store 95 Tg CO2-eq in the biomass and top meter of soil, equivalent to about 25% of the CO2 emissions of Spain and Portugal in 2022. The average rate of accumulation of organic carbon to the soil stock was estimated at 0.15 Tg CO2-eq y-1, equivalent to 0.04% of the annual anthropogenic CO2eq emissions of these two countries (in 2022). Additionally, the loss of BCEs in Spain and Portugal over the last century may have released 11-27 Tg CO2-eq, whereas we predicted that 1.3-5.6 Tg CO2-eq will be released over the next 30 years. Which underscores the urge to increase conservation and restoration efforts. This study provides the first comprehensive Spanish and Portuguese national blue carbon inventory for its inclusion in NDCs, providing baseline data for the implementation of blue carbon offsetting projects. Thu, 01 Jan 2026 00:00:00 GMT https://accedacris.ulpgc.es/jspui/handle/10553/163216 2026-01-01T00:00:00Z