BUSCADOR RECOLECTA

The present work aims to provide corrosion performance data for an additively manufactured Ti6Al4V alloy in saline and polluted environments. The as-received additively manufactured material underwent heat treatment at 850 °C for 3 h to transform the acicular α’ microstructure into a lamellar α microstructure. Comparative corrosion assessments were conducted between the heat-treated substrates, the as-received condition, and a conventionally mill-annealed alloy. Potentiodynamic polarization experiments were carried out in saline (3.5 wt.% NaCl) and acid aqueous media ((NH4)2SO4 containing Harrison’s solution). The corrosion performance of additively manufactured substrates matched or surpassed that of the conventional alloy in Harrison’s solutions while remaining inferior in saline medium, despite forming a thicker passive film. Overall, the XY plane showed better corrosion performance, particularly after the elimination of the acicular α’ martensite by the applied heat treatment. The results also suggested that the presence of the coarse β phase was beneficial in 3.5 wt.% NaCl solution and detrimental in Harrison’s solutions, more so in acidified and fluorinated conditions.

Bioactive plasma electrolytic oxidation (PEO) coatings were developed on a wrought Mg0.5Zn0.2Ca alloy using a transparent electrolyte for easy maintenance and waste disposal, compared to a conventional suspension-based solution. Treatment times of 300, 600, and 900 s were evaluated for their effects on coating morphology, composition, and corrosion resistance. A short-time electrochemical impedance spectroscopy (EIS) screening was utilized to identify coatings with optimal corrosion protection. To assess the degradation rate and corrosion mechanisms, hydrogen evolution was monitored under pH-controlled quasi-in vivo conditions over extended immersion periods. Coating thickness increased by only 3% from 300 to 900 s of treatment (13 and 18 µm, respectively), with pore bands formed near the barrier layer at 900 s. The short-term EIS screening revealed that the coatings produced at 600 and 900 s were less protective and consistent than those at 300 s due to the presence of pore bands, which increased permeability. Hydrogen evolution measurements during 5 days of immersion at pH 7.4 indicated a tenfold higher degradation rate of the PEO-coated alloy compared to the bare substrate. Therefore, none of the PEO coatings provided effective corrosion protection after 24 h of immersion, which is attributed to crack formation at the PEO/corrosion products interface. This highlights the importance of crevices in the corrosion of Mg-Zn-Ca alloys. The presence of ZnO exacerbates the corrosion of magnesium in crevice areas.

In this study, a phosphate-based conversion coating (PCC) was applied as a precursor before forming silicate-fluoride (SiF) and silicate-phosphate-fluoride (SiPF) based flash-plasma electrolytic oxidation (Flash-PEO) coatings on AZ31B magnesium alloy. The main novelty is the successful incorporation of calcium, zinc, manganese and phosphate species into the Flash-PEO coatings via a precursor layer rather than using the electrolyte. The precursor also led to longer lasting and more intense discharges during the PEO process, resulting in increased pore size. Corrosion studies revealed similar short-term performance for all coatings, with impedance modulus at low frequencies above 107 Ωcm2, and slightly better performance for the SiPF-based coating. Nonetheless, the enlarged pores in the PEO coatings functionalized with the PCC precursor compromised the effectiveness of self-healing mechanisms by creating diffusion pathways for corrosive species, leading to earlier failure. These phenomena were effectively monitored by recording the open circuit potential during immersion in 0.5 wt.% NaCl solution. In summary, this study demonstrates that conversion coatings are a viable option for the functionalization of PEO coatings on magnesium alloys, as they allow for the incorporation of cationic and other species. However, it is crucial to maintain a small pore size to facilitate effective blockage through self-healing mechanisms.

Corrosion fatigue is a major factor leading to sudden failures in load-bearing orthopaedic implants, particularly in biodegradable ones that corrode more quickly than permanent implants. In the current study, we developed a novel modified-in vitro corrosion fatigue (MICorF) rig that incorporates several key parameters—such as loading mode, blood buffering capacity, gradual bone healing processes, and the synchronization of corrosion and cyclic damage—aimed at closely mimicking in vivo conditions. The functionality of the MICorF was tested with an experimental extruded ZX00 (Mg-0.5Zn-0.5Ca) Mg alloy. The results showed that the ZX00 Mg alloy possesses a limited biomechanical performance. Based on the SEM micrographs, the presence of intermetallic particles in the alloy microstructure and the subsequent galvanic corrosion phenomena could be taken as the main cause of failure. According to the results yielded by the MICorF, the ZX00 alloy withstands at least 20 days under the studied physiological conditions and polarization corresponding to the pitting conditions.

Pilot Survey CiudCovid2020 (See: How Did the Pandemic Shape the Dynamics of Two Civic Communities?: Unraveling Complementarities and Divergences Within Spain’s Civic CultureWithin Spain’s Civic Culture)

Es la base de datos que ha permitido realizar los artículos siguientes: - Fernández-Cruz, F.J.; Rodríguez-Mantilla, J.M. & Fernández-Díaz, M.J. (2020). Impact of the application of ISO 9001 standards on the climate and satisfaction of the members of a school, International Journal of Educational Management, Vol. 34 Iss: 7, pp. 1185-1202. https://doi.org/10.1108/IJEM-10-2018-0332 (ISSN: 0951-354X) - Rodríguez-Mantilla, J.M.; Martínez-Zarzuelo, A., & Fernández-Cruz, F.J. (2020). Do ISO:9001 Standards and EFQM Model differ in their impact on the External Relations and Communication System at schools?, Evaluation and Program Planning Vol. 80, DOI: https://doi.org/10.1016/j.evalprogplan.2020.101816 (ISSN: 0149-7189) - Fernández-Cruz, F.J.; Rodríguez-Mantilla, J.M. & Fernández-Díaz, MªJ. (2019). Assessing the impact of ISO:9001 implementation on school teaching and learning processes, Quality Assurance in Education, Vol. 27 Iss: 3, pp. 285 - 303 (ISSN: 0968-4883) DOI: https://doi.org/10.1108/QAE-09-2018-0103 - Rodríguez-Mantilla, J.M., Fernández-Cruz, F.J. &. Fernández-Díaz, MªJ. (2019). Comparative analysis between management team and teachers on the impact of ISO 9001 standards in educational centres, International Journal of Quality and Service Sciences, Vol. 11, Nº 2 (248-264) DOI: https://doi.org/10.1108/IJQSS-06-2018-0057 (ISSN 1756-669X) - Rodríguez-Mantilla, J.M., Fernández-Cruz, F.J. &. Fernández-Díaz, MªJ. (2018). Factors associated with the impact of implementing quality management systems at schools: a multilevel analysis, Total Quality Management & Business Excellence, Vol. 31, 1-17 DOI: http://dx.doi.org/10.1080/14783363.2018.1490642 (ISSN: 1478-3363)

Leveraging an array of search criteria including composers, singers, theatres, geographical territories, sources, and more, scholars can delve into the nuances of performance practices and historical contexts around Metastasio’s drammi per musica. Furthermore, the DIDONE Arias Database offers a treasure trove of individual arias extracted from these performances, providing a unique opportunity to explore the interplay of musical elements such as key, scoring, time signature, vocal range, and other parameters. Beyond its scholarly utility, the DIDONE Database invites users to embark on a journey of exploration and discovery, offering a dynamic platform where the scores of these historic arias can be visualised and explored within the broader context of 18th-century operatic tradition.

Se trata de una encuesta de clima laboral durante el año 2023 llevado a cabo por la Biblioteca Universidad Complutense de Madrid, más concretamente por el Servicio de Evaluación de Procesos y Centros

This dataset in an Excel file compares the wave of globalization before the outbreak of the Great Recession in 2007 with its alleged historical antecedent before the outbreak of World War One. We describe trends in trade and openness, estimate the gains from trade and investigate the proximate causes of the growth of openness. We argue that the conventional wisdom has to be revised. The first wave of globalization started around 1820 and culminated around 1870. In the next century, trade continued to grow, with the exception of the Great Depression, but openness and gains fluctuated widely. Growth resumed in the early 1970s. By 2007, the world was more open than a century earlier and its inhabitants gained from trade substantially more than their ancestors did. The current wave of globalization, in spite of some similarities with previous trends, has no historical antecedents. This dataset is related to the working paper "A tale of two globalizations : gains for trade and openness 1800-2010" by by Giovanni Federico and Antonio Tena Junguito, available on: http://hdl.handle.net/10016/22354