http://hdl.handle.net/10498/6768 Sun, 10 May 2026 01:55:18 GMT 2026-05-10T01:55:18Z http://hdl.handle.net/10498/38618 Development and Mechanical Analysis of Geopolymers Formed with Mining Residue and Fly Ash from Municipal Solid Waste Incineration Obtained After the Neutralisation Stage Terrones-Saeta, A.; Terrones Saeta, Juan María; Suárez Macías, Jorge; Iglesias Godino, Francisco Javier; Corpas Iglesias, Francisco Antonio Renewable energy sources are presented as a key solution to today’s energy needs, but they also generate waste that can have a negative impact on the environment. In particular, fly ash from the incineration of municipal solid waste (MSW), classified as hazardous by European regulations, is often deposited in landfills due to its lack of usefulness. This research proposes its valorisation in geopolymers, combining it with mining to create a sustainable material with a high industrial waste content. Firstly, all the wastes involved were characterised, which allowed for the development of a high-quality geopolymer from mining residue activated with 5% NaOH. This material was enriched with up to 50% fly ash (in increasing percentages) with the aim of making it inert, retaining it in the geopolymer matrix, and observing its effect on the final material. The physical and mechanical properties of the geopolymers obtained were evaluated, demonstrating that they do not produce contaminating leachates. The results indicate the feasibility of developing a geopolymer with up to 20% fly ash, obtaining a building material comparable to traditional ceramics, suitable for commercialisation, with a lower environmental impact and in line with the principles of the circular economy Thu, 19 Jun 2025 00:00:00 GMT http://hdl.handle.net/10498/38618 2025-06-19T00:00:00Z http://hdl.handle.net/10498/38053 Container Traffic in the Colombian Caribbean: A Competitiveness Analysis of the Port of Santa Marta Through a Technical–Economic Combination Framework Pabón Noguera, Adriana; Cerbán Jiménez, María del Mar; Ruiz Águilar, Juan Jesús The Port of Santa Marta, located on Colombia’s northern Caribbean coast, plays a vital role in the country’s maritime trade, particularly in the export of agricultural and perishable goods. This raises the question: how competitive is Santa Marta’s container terminal compared to national and regional ports, and what strategic factors shape its performance within the Colombia and Latin American maritime logistics system? Methods: This study evaluates the port’s competitiveness by applying Porter’s Extended Diamond Model. A mixed-methods ap-proach was employed, combining structured surveys and interviews with port stakeholders and operational data analysis. A competitiveness matrix was developed and examined using standardized residuals and L1 regression to identify critical performance gaps and strengths. Results: The analysis reveals several competitive advantages, including the port’s strategic location, natural deep-water access, and advanced infrastructure for refrigerated cargo. It also benefits from skilled labour and proximity to global shipping routes, such as the Panama Canal. Nonetheless, challenges remain in storage capacity, limited road connectivity, and insufficient public investment in hinterland infrastructure. Conclusions: While the Port of Santa Marta shows strong maritime capabilities and spe-cialized services, addressing its land-side and institutional constraints is essential for positioning it as a resilient, competitive logistics hub in the Latin American and Caribbean region. Fri, 27 Jun 2025 00:00:00 GMT http://hdl.handle.net/10498/38053 2025-06-27T00:00:00Z http://hdl.handle.net/10498/38052 Examining the influence of corruption on port efficiency in West Africa and the Mid-Atlantic: A bootstrapped DEA analysis Rodríguez, Andrea; Gil Ropero, Antonio; Cerbán Jiménez, María del Mar; Trujillo, Lourdes This study offers valuable information for policymakers. As European ports are increasingly subject to stringent environmental regulations, it is essential to consider the competitive impact on EU ports geographically located in Africa (also because the Canary Islands are considered outermost regions of the EU). Policymakers should weigh the long-term consequences of regulatory asymmetries on trade flows, competitiveness, and the strategic positioning of European ports. In this regard, the study highlights the need for a coordinated regulatory strategy that considers the unique competitive dynamics faced by European ports operating in African contexts. Wed, 18 Jun 2025 00:00:00 GMT http://hdl.handle.net/10498/38052 2025-06-18T00:00:00Z http://hdl.handle.net/10498/38041 Additive vs. Subtractive Manufacturing: A Comparative Life Cycle and Cost Analyses of Steel Mill Spare Parts Segovia Guerrero, Luis; Baladés Ruiz, Nuria; Gallardo-Galán, Juan J.; Gil Mena, Antonio José; Sales Lérida, David In the context of growing environmental concerns and the demand for more sustainable manufacturing practices, this study evaluates the environmental and economic performance of two production routes for a stainless steel support block used in steel mills. A comparative Life Cycle Assessment (LCA) and Life Cycle Costing (LCC) were conducted to assess a conventional subtractive manufacturing process based on Computer Numerical Control (CNC) machining versus a hybrid approach that combines Plasma Arc-Wire Arc Additive Manufacturing (PA-WAAM) with CNC finishing. The LCA was carried out using ReCiPe 2016 Midpoint and Endpoint methodologies in SimaPro, while the LCC employed a cradle-to-gate cost model. Results showed that the hybrid WAAM-CNC route reduced average environmental impacts by 49% across 18 categories and decreased steel consumption by approximately 70% due to near-net-shape fabrication. Although the hybrid method incurred an approximate 3.5 times increase in unit production cost, this was primarily attributed to equipment investment. In contrast, operational costs such as labor, materials, and consumables were significantly lower—by 66%, 28%, and 45%, respectively. These findings support the hybrid approach as a more sustainable manufacturing alternative with the potential for long-term cost optimization as additive technologies mature. Tue, 01 Apr 2025 00:00:00 GMT http://hdl.handle.net/10498/38041 2025-04-01T00:00:00Z