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Screening of variables affecting the selective leaching of valuable metals from waste motherboards’ PCBs
Get PDFThe presence of valuable and hazardous metals in waste printed circuit boards, especially, motherboards, makes their recovery necessary as implies great economic and environmental advantages and develops urban mining processes. Hence, this research is focused on the selective leaching of Cu, Pb, and Sn as base metals using nitric acid and hydrochloric acid and Au, Ag, and Pd as precious metals using thiourea and sodium thiosulfate from waste motherboards’ PCBs in a sequential eco-friendly two-stage process. Previously, thiourea and sodium thiosulfate were used as leaching agents to investigate their applicability for the leaching of metals from PCBs in a single-stage process. Screening experimental design was applied to screen the variables affecting the leaching process in order to evaluate their impact on the recovery of metals and select the significant factors. The results demonstrated that base and precious metals can be leached appropriately in two consecutive stages compared to a single-stage process. Nitric acid was found to be a much more efficient agent to leach Cu and Pb in comparison with hydrochloric acid which was more suitable for the leaching of Sn. In the case of precious metals, higher amounts of Au were leached using thiourea, whereas sodium thiosulfate was able to leach more Pd. Roughly similar results were obtained for the leaching of Ag using these leaching agents. Nitric acid concentration, average particle size, temperature, and leaching time were found to be significant to maximize the leaching of Cu and Pb and minimize that for Au, Ag, and Pd in the first stage. Initial pH was the only variable influencing the second stage, in particular, Au leaching by thioureaOpen Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This work is part of I + D + i project Reference PID2021-122923NB-I00 financed by MCIN/AEI/https://doi.org/10.13039/501100011033/FEDER, UES
Monográfico Carmen Blanco
Get PDFO número 35 de Evohé, dirixido por Laura Paz Fentanes e ilustrado por Sara Lamas, contén un monográfico dedicado á escritora, investigadora e profesora Carmen Blanco, conformado pola súa bibliografía e por diversos traballos sobre as distintas vertentes da súa obra: a poesía por Manuel Fernández Rodríguez, a narrativa breve por Olga Novo, a novela por Armando Requeixo, o ensaio por Marcela Bao, a tradución por María Lopo, o deseño por Cristina Fiaño e o mestrado por Mariña Rodríguez Blanco. Seguidamente, aparece a versión multilingüe do seu lema “Amo, mais non teño amo” a cargo de Adina Ioana Vladu e os poemas que lle dedicaron expresamente os poetas Luz Pozo Garza, Xohana Torres, Marta Pessarrodona, Olga Novo e Claudio Rodríguez Fer.
No apartado creativo aparecen varias traducións ao galego dende o castelán (o relato “A cámara negra”, de Eugenio Granell, por Laura Paz Fentanes); ao ruso dende o galego (o poema “Astrolabio”, de Luz Pozo Garza, por Ekaterina Yakovleva) e ao checo dende o galego (o poema “Praga”, de Claudio Rodríguez Fer, por Anna Hozmanová e Karolina Nohynková). Finalmente, aparece o artigo “James Joyce na obra e na biblioteca de José Ángel Valente”, por Laura Paz Fentanes
Novel Hybrid Electrocatalyst Materials for Advanced Energy Conversion Technologies
No full textThe thesis addresses the study of new carbon-based materials
and their applications in the field of energy conversion.
This study delves into the development of new metal-carbon
hybrid electrocatalysts, which play a key role in improving the
efficiency and sustainability of various energy conversion
technologies. The main objective of this thesis is to develop a
methodology for the electrochemical exploitation of precious
metals for applications related to the electrolysis of water and
urea, as well as fuel cells. To this end, a new class of hybrid
carbon nanostructures will be developed to support
electrochemically active metallic nanostructures that will act as
catalysts for energy conversion.2025-01-2
A geometric-identification–free mathematical model for recreating nonsymmetric horizontal railway alignments
Get PDFThe constant passage of trains on the railways tracks causes, in the course of time, deviations that must be corrected periodically by means of a track calibration process. It consists of designing a new layout, called recreated horizontal alignment (RHA), as close as possible to the deformed center track fulfilling also the technical constraints according to the operational requirements of the railway. In recent years, different models have been proposed to address this task. This paper proposes, first, a new geometrical model that works with continuous variables for the definition of horizontal alignments (HAs) to deal with nonsymmetric transition curves at both sides of a circular curve and second, an optimization algorithm to compute the recreated alignment suitable in sinuous railway sections. This new mathematical model frees the optimization process from the need to previously identify the geometric elements (tangents, circular curves, and transition curves) of the HA. The usefulness of this model is tested with two academic examples showing its good behavior and in a real case study, where this algorithm is compared with the solution adopted by the engineers in a section of the railway line Ourense–Monforte in the NW of Spain.We would like to thank https://www.ineco.com/ (Transport Engg. and Economics) of its disposition to share the data in the case study. This work was funded from the project TED2021-129324B-I00 of the Ministerio de Ciencia
e Innovación (Spain) and NextGenerationEU (European Union), and also by the Collaboration Agreement between
Consellería de Educación, Formación Profesional e Universidades (Xunta de Galicia, Spain) and Universidade de
Santiago de Compostela (Spain), which regulates the Specialization Campus Campus Terra under Grant Number
2022-PU014. Finally, the third author thanks the support given by Xunta de Galicia (Spain) by means of the research project 2023 GPC GI-2084-ED431B2023/17 and the fourth author has received financial support from the Xunta de Galicia 2021 GRC GI-1563-ED431C2021/15.S
Resolución Rectoral del 14-02-2024 por la que se publica la Convocatoria anticipada en los estudios de máster universitario oficial para el alumnado con titulaciones de acceso de países ajeos al EEES. Curso académico 2024-2025
No full textXA141
Resolución rectoral del 02-02-2024 por la que se publica la convocatoria para el acceso a las enseñanzas universitarias oficiales de grado para las personas mayores de 40 años que acrediten experiencia profesional o laboral. Curso académico 2024-25
No full textXA141
Ciencias da Educación: sexenios 2023
Get PDFMaterial empregado na sesión formativa desenvolvida pola Biblioteca de Psicoloxía e CC Eduación da USC para o persoal docente e investigador da Facultade de CC da Educación, acerca das novidades introducidas pola ANECA na convocatoria de sexenios de 2023. Inclúe recomendacións para elaborar as narrativas das achegas presentadas á convocatoria e pautas para atopar os distintos indicios de calidade requiridos para acadar unha avaliación positiva do/s tramo/s sometido/s a avaliación.Material empleado en la sesión formativa desarrollada por la Biblioteca de Psicología y CC Eduación de la USC para el personal docente e investigador de la Facultad de CC de la Educación, acerca de las novedades introducidas por la ANECA en la convocatoria de sexenios de 2023. Incluye recomendaciones para elaborar las narrativas de las aportaciones presentadas a la convocatoria y pautas para encontrar los distintos indicios de calidad requeridos para alcanzar una evaluación positiva del tramo o tramos sometido/s a evaluación
A Comprehensive Study on Tear Meniscus Height Inter-Eye Differences in Aqueous Deficient Dry Eye Diagnosis
Get PDFBackground: Dry eye disease (DED) is a chronic ocular surface condition that requires precise diagnostic tools. The present study aimed to investigate the diagnostic potential of the absolute inter-eye difference (|OD-OS|) in tear meniscus height (TMH) for the detection of the presence of aqueous deficient dry eye (ADDE).
Methods: A sample of 260 participants with dry eye complaints underwent ocular surface examinations thorough diagnostic assessments based on the Tear Film and Ocular Surface Society guidelines (TFOS DEWS II). Participants were subsequently categorized as No ADDE and ADDE based on TMH. Statistical analyses to determine the optimal TMH|OD-OS| cut-off value in a randomly selected study group (200 participants) were performed, while a separate validation analysis of the cut-off value obtained in a random cross-validation group (60 participants) was also performed. (3) Results: The significant diagnostic capability of TMH|OD-OS| (area under the curve = 0.719 ± 0.036, p < 0.001) was found. The identified cut-off value of 0.033 mm demonstrated reliable specificity (77.6%) and moderate sensitivity (59.1%). Cross-validation confirmed the cut-off value’s association with the TFOS DEWS II diagnostic criterion (Cramer’s V = 0.354, p = 0.006). (4) Conclusions: The present study provides evidence for the diagnostic potential of TMH|OD-OS| in identifying ADDE. The identified cut-off value enhances the specificity and offers moderate sensitivity, providing an objective tool for clinical decision making.S
Associations between Ocular Biometry, Refractive Error, and Body Characteristics
Get PDFMyopia is a refractive error widely spread throughout the world, usually related to excessive axial length (AL) of the eye. This elongation could have severe consequences, even leading to blindness. However, AL varies among subjects, and it may be correlated with other anthropometric parameters. The aim of this study was to evaluate the relationships between AL, body height, refractive error, and sex. A total of 72 eyes of 36 myopic participants with a mean age of 11.1 ± 1.42 years (ranging from 8 to 14 years) were included in the study. Participants underwent objective refraction by NVision-K5001, AL measurement by Topcon MYAH biometer, and body height measurement. Significant correlations were observed between AL, body height, and spherical equivalent (SE) (Spearman’s correlation, all p ≤ 0.016). When participants were grouped by AL, significant differences were observed for body height and SE, and when grouped by height percentile, significant differences were observed for AL and SE (Kruskal–Wallis test, all p ≤ 0.006). There was a significant difference in SE, AL, and body height between genders (Mann–Whitney U test, all p ≤ 0.038). AL relates to the refractive state of the eye and is also influenced by individual anatomical characteristics.S
Papel de la señalización de los astrocitos en la regulación del comportamiento circadiano y el equilibrio energético a través de AMPK
Get PDFEn esta tesis doctoral se investiga el papel de la señalización de
AMPK en los astrocitos sobre el control de los patrones
de comportamiento circadiano y la homeostasis energética en
ratones. Para ello, hemos generado ratones condicionales
inducibles con deleción de la subunidad reguladora AMPKγ2 en
astrocitos, así como ratones con ablación específica de
AMPKγ2 en astrocitos del núcleo ventromedial del hipotálamo.
Nuestros hallazgos revelan que la activación de AMPK en
los astrocitos altera la sincronización de los ritmos circadianos
a la luz y al patrón de alimentación, así como la
homeostasis energética. Este descubrimiento arroja luz sobre la
compleja interacción entre los ritmos circadianos, la
señalización de AMPK y la regulación de la energía en el
organismo.2025-04-1