瓦伦西亚理工大学

This study performs the analysis of oxymethylene ether (OMEx) spray combustion in a quiescent combustion chamber at Diesel-like conditions following the Engine Combustion Network guidelines. The paper presents the incorporation of an Unsteady Flamelet Progress Variable combustion model into a Large Eddy Simulation workflow and the corresponding experimental validation that produces strong agreement in terms of main spray development (tip penetration) and combustion (ignition delay and lift-off length) metrics. Furthermore, good agreement is also found for the spatial distribution of relevant species that describe the low- and high-temperature ignition stages, namely CH2O and OH. Particular attention is paid to the prediction of chemiluminescence species (OH∗, CH∗, C2∗), which can be validated by experimental image recording. This step is shown to be critical for the prediction of experimental OH∗ fields. Using ground-state OH, which is often found in the literature, is not good practice, as the spatial location of both excited- and ground-state species is highly different, especially for non-sooting fuels such as OMEx. Among the different simulated chemiluminescent species, OH∗ is found to be the best tracer of the flame location due to its widely spread spatial distribution. Finally, the fuel age concept is implemented into the simulation as a passive scalar, and it is found to provide valuable insights into mixing history and transient combustion processes. Its correlation with species distributions reveals that regions of high OH concentration coincide with elevated fuel age, reflecting near-equilibrium conditions, while OH∗ dominates younger rich mixtures near the lift-off length, where chemical state is not yet at equilibrium. Future work will focus on applying the proposed methodology across a wider range of ECN conditions and fuels to both improve the understanding of e-fuels combustion behaviour relative to conventional fuels and further develop integrated CFD–optical diagnostic validation strategies for spray combustion research.

This study investigates the high-temperature oxidation behavior and microstructural evolution of Ti-35Nb-6Mo β-titanium alloy at 600 °C, 700 °C, and 800 °C for exposure durations from 0.5 to 72 h. A comprehensive experimental approach combining gravimetric analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), focused ion beam (FIB) cross-sectional analysis, optical profilometry, and contact angle measurements was employed. The oxidation kinetics exhibited a strong temperature dependence. At 600 °C, oxidation followed near-linear kinetics with low mass gain, indicating the formation of a thin and protective oxide layer. At 700 °C, the kinetics transitioned to diffusion-controlled behavior, consistent with parabolic trends, associated with the development of a multilayered oxide scale comprising rutile TiO2 and sub-stoichiometric Ti3O5. At 800 °C, oxidation became non-protective, showing sustained linear kinetics and significantly higher mass gain due to oxide scale cracking, porosity, and spallation. Microstructural analysis revealed progressive oxide thickening and increased crystallinity with temperature, with rutile TiO2 dominating at higher temperatures. Surface roughness increased markedly with oxidation severity, while contact angle measurements demonstrated enhanced hydrophilicity due to combined effects of oxide chemistry and surface topography. The results demonstrate that Ti-35Nb-6Mo exhibits stable oxidation resistance up to 700 °C, while degradation at 800 °C defines its upper thermal limit. These fundamental baseline findings provide insights into the alloy’s thermal stability limits for high-temperature engineering and demonstrate the potential of controlled thermal oxidation as a surface-engineering pre-treatment strategy for biomedical implants.

Green solvent strategies are increasingly important for advancing sustainable polymer processing and deepening the understanding of structure–property relationships. In this work, we report a coaxial electrospinning approach that employs dimethyl sulfoxide and ethyl acetate as environmentally benign solvents to fabricate nanofibers composed of polyvinyl alcohol (PVA) cores and poly(L-lactic acid) (PLLA) shells. Comprehensive morphological and physicochemical characterization confirmed the successful formation of uniform, defect-free core–shell architectures. Comparative transport studies revealed clear architecture-dependent behavior: uniaxial PVA fibers displayed rapid burst release, PLLA-only fibers acted as complete diffusion barriers, and coaxial PVA/PLLA fibers enabled finely tunable, diffusion-controlled transport over extended timescales. These findings establish direct links between solvent choice, processing architecture, and transport properties in biodegradable nanofiber systems. This study provides both a scalable eco-conscious electrospinning strategy and a fundamental framework for correlating processing, morphology, and mass transport in polymeric materials.

In this work, of photoelectrooxidation experiments of three emerging contaminants (ECs), typically found in the Albufera of Vale`ncia such as bentazon (BTZ), diclofenac (DFC) and imazalil (IMZ), were performed using a ceramic electrode made of Sb-SnO2coated with Bi2WO6 as a photocatalyst. When studied individually on a mixed electrolyte of Na2SO4 and NaCl, DFC and IMZ achieved a 100 % degradation in every test, and their mineralization improved the higher the current density and in presence of light, achieving 58.7 % and 63.7 % after 4 h, respectively. Not only reactive oxygen species (ROS) but also reactive chlorine species (RCS) had a major role in the degradation of both ECs. ROS and RCS were further generated photochemically, generally leading to greater oxidation under light application. In the mixture of the three ECs, all could achieve 100 % degradation at 50 mA center dot cm-2 and in the presence of light. Mineralization of the mixture achieved 65 % under these conditions. In general, light influence was greater at lower current densities. In the real wastewater experiments every target pollutant achieved 100 % degradation. The mineralization achieved was 42.2 %, relatively lower. This was attributed to the presence of Natural Organic Matter (NOM) and other inorganic ions which hindered mineralization. These results confirm that these photoanodes are quite sensitive to light and are capable of oxidizing complex organic molecules of different chemical structures not only in synthetic matrices but also in real water, opening future possibilities to in-situ water treatments.

This research addresses the critical need to study human capital and organizational design in the construction industry. To overcome the scarcity of literature on the functionality and responsiveness of organizational charts, this study carries out a comparative analysis of large-scale construction projects in Chile and Peru. Using a multiple-case study approach and a Complex Adaptive Systems (CAS) framework, the research examined how organizational structures configure and adapt to local contexts through semi-structured interviews, exploring the influence of external factors such as regulations, the market, and culture on the design of organizational charts. The results reveal that while Peruvian structures tend toward centralization influenced by cultural factors, Chilean structures exhibit greater horizontality. Furthermore, Lean philosophy emerged as a key contextual factor that facilitates organizational adaptability in complex environments. The study concludes that organizational adaptability is not merely a product of formal design, but an emergent property driven by the interaction between formal roles and management practices. These findings contribute to a deeper understanding of how construction firms can configure their structures to better respond to project complexity. For future research, it is proposed to explore the correlation between the complexity of organizational charts and project performance, using quantitative and qualitative indicators, and analyzing the evolution of organizational structures throughout the project life cycle. In addition, it is suggested to investigate the impact of digitalization and agile methodologies, as well as to conduct longitudinal studies to assess the resilience and adaptability of organizational charts to regulatory and market changes.