Dmitri NIKULIN, Neoplatonism in Late Antiquity, Oxford, Oxford University Press, 2019, 296 páginas, ISBN 978-0190662363

Review: Dmitri Nikulin, Neoplatonism in Late Antiquity, Oxford, Oxford University Press, 2019, 296 páginas, ISBN 978-0190662363Reseña de Dmitri Nikulin, Neoplatonism in Late Antiquity, Oxford, Oxford University Press, 2019, 296 páginas, ISBN 978-019066236

Performance analysis and modelling of a 50 MW grid-connected photovoltaic plant in Spain after 12 years of operation

[EN] This study aims to estimate the performance and losses of a 50 MW photovoltaic (PV) utility-scale after 12 years of operation. The PV plant has monocrystalline and polycrystalline silicon modules and is located in the central region of Spain with an annual insolation of 1976 kWh/m2. Monitoring data over the entire year 2020 has been analyzed and filtered to assess the performance results following the IEC 61724 standard guidelines. The annual average reference yield, final yield, performance ratio and capacity utilization factor are of 5.44 h/d, 4.28 h/d, 79.24%, and 19.77%, respectively. Besides the experimental analysis, this work improves the estimation of the daily performance ratio, especially in days with low insolation. Two different modelling approaches have been assessed and compared. In first place, a physical model has been adopted, based on the most common losses, and including an exponential expression to account for low irradiance losses. In second place, statistical models have been used, with either multiple linear regressions or random forest algorithms. In contrast with other published models which require many inputs, the best accuracy has been reached with the random forest model using only the ambient temperature and solar irradiance as predictors, obtaining a RMSE of 1% for the PR and for the energy production.The authors gratefully acknowledge the operation & maintenance staff of the PV Power Plant in Olmedilla de Alarcon ¿ for providing the measured data of the solar PV power plant.Fuster-Palop, E.; Vargas-Salgado, C.; Ferri-Revert, JC.; Payá-Herrero, J. (2022). Performance analysis and modelling of a 50 MW grid-connected photovoltaic plant in Spain after 12 years of operation. Renewable and Sustainable Energy Reviews. 170:1-17. https://doi.org/10.1016/j.rser.2022.11296811717

Dynamic autonomous set-up of relays in Bluetooth mesh

BLE-based mesh networks are based on a simple flooding algorithm with some mechanisms to reduce network saturation, called managed flooding. The operating parameters of the network establish its performance, but in an industrial environment the operating conditions are not permanent, so a system that can adjust to these changes is necessary. A global decision system is not valid since each part of the network may have different properties. An autonomous system that does not introduce an overhead of message exchange is necessary for its operation. This paper proposes an algorithm based on the information provided by a single control message exchange that allows each node to autonomously select its operating parameters to improve the quality of links with neighbouring nodes and thus improve the overall performance of the network

Theory of Caroli-de Gennes-Matricon analogs in full-shell nanowires

Full-shell nanowires are hybrid nanostructures consisting of a semiconducting core encapsulated in an epitaxial superconducting shell. When subject to an external magnetic flux, they exhibit the Little-Parks (LP) phenomenon of flux-modulated superconductivity, an effect connected to the physics of Abrikosov vortex lines in type-II superconductors. We show that full-shell nanowires can host subgap states that are a variant of the Caroli-de Gennes-Matricon (CdGM) states in vortices. These CdGM analogs are in fact shell-induced Van Hove singularities in propagating core subbands. We elucidate their structure, parameter dependence and behavior in tunneling spectroscopy through a series of models of growing complexity. We show through microscopic numerical simulations that they exhibit a characteristic skewness towards high magnetic fields inside non-zero LP lobes resulting from the interplay of three ingredients. First, core subbands exhibit a diamagnetic response, so that they disperse with flux depending on their generalized angular momentum. Second, the band bending at the core/shell interface induces a ring-like profile on the CdGM analog state wavefunctions with average radius smaller than the core radius. And last, degeneracy points emerge where all the CdGM Van Hove singularities coalesce. This happens when the flux threading each wavefunction is equal to an integer multiple of the flux quantum, a condition that shifts the degeneracy points away from the center of the LP lobes, skewing the CdGM analogs. Our analysis unlocks a transparent analytical description that allows to extract precise microscopic information about the nanowire by measuring the energy and skewness of CdGM analogs.Comment: 15 pages, 9 figure

Innovative regression-based methodology to assess the techno-economic performance of photovoltaic installations in urban areas

[EN] Households present a significant contribution in the national energy consumption, and photovoltaics (PV) has become an economically feasible technology that can play an important role to lower this consumption and the associated emissions. Nevertheless, there is still a gap between too in-depth technical models for detailed studies and what urban energy planners need, which are simpler, yet reliable techno-economical tools to select which roofs of city buildings are the best candidates for PV production. In order to face this gap, a multiple linear regression (MLR) model has been developed to determine the economic payback using dimensionless parameters. The methodology has been adopted in the city of Valencia (Spain) for a large sample of multi-storey buildings, which are the most common typology. The approach has a high replicability since it can be applied for different countries. The MLR model provides a payback root mean squared error (RMSE) of 0.48 years in comparison with a complex techno-economic model which was previously developed and validated with the software System Advisor Model (SAM). The variables which have a bigger weight in the payback are the shadow losses and the power unit cost due to the economy of scale. With the current Spanish regulation, PV installations on multi-storey buildings can reach paybacks of around 7-15 years and the best option is to have large economies of scales together with a low energy surplus.This study was developed owing to the support provided by the Chair of Urban Energy Transition of the Universitat Politecnica de Valencia and the foundation Las Naves. Additionally, this work was supported by The Energy Office of Valencia and the Statistics Office of the Valencia City Council, who collaborated by providing the data of the PV facility for the validation and their recommendations on the statistical analysis.Fuster-Palop, E.; Prades-Gil, C.; Masip, X.; Viana-Fons, JD.; Payá-Herrero, J. (2021). Innovative regression-based methodology to assess the techno-economic performance of photovoltaic installations in urban areas. Renewable and Sustainable Energy Reviews. 149:1-15. https://doi.org/10.1016/j.rser.2021.111357S11514

Biomarkers of Exposure to Zearalenone in In Vivo and In Vitro Studies

The measurement of human exposure to mycotoxins is necessary for its association with adverse health effects. This exposure is usually estimated from contamination levels of foodstuffs, which are the primary source of toxin exposure, and data on food consumption patterns. However, variations in contamination level, intestinal absorption, toxin distribution, and excretion lead to individual variations in toxin exposure that can be more readily measured with a biomarker. This review deals with the latest literature information about ZEN biomarkers in humans, animals, and cell line cultures. Their presence in urine, biomarkers that have effects in the kidney, liver, reproductive system and blood and biomarkers of cell response have been reported. It has highlighted the importance of determining a-zearalenol and ß-zearalenol biomarkers to estimate the probable dietary intake (PDI) of a specific population or to characterize the severity of exposure to ZEN in animals or cell lines. a-ZEL and ß-ZEL are cytotoxic by inhibiting cell proliferation, total protein and DNA syntheses, in this sense, an induction of expression proteins Hsp27 and Hsp70 was observed, and an increase in gene expression (TLR4, NF-kBp65, TNF-a, IL-1ß, IL-6, IL-8, MGMT, a-GST, Hsp70, Nrf2, L-Fabp, HO-1, MAPK8), the determination of which indicates an oxidative stress effect. The integrity of the cell or tissue membrane is assessed by lactate dehydrogenase (LDH), which increase at exposure of ZEN (84.2 µM), and the proportions of some fatty acids of the renal tissue membrane were increased at treatments with ZEN. This review allows starting future studies of animal and population exposure in parallel with those of health effects works. © 2022 by the authors. Licensee MDPI, Basel, Switzerland

Static Postural Control during Single-Leg Stance in Endurance, Team and Combat Athletes from the Spanish National Sport Technification Program

In the context of pediatric physical exercise, the analysis of factors affecting postural control (PC) provides insight into the development of sport-specific motor skills. This study aims to evaluate the static PC during single-leg stance in endurance, team and combat athletes from the Spanish National Sport Technification Program. A total of 29 boys and 32 girls, aged 12 to 16 years old, were recruited. Centre of pressure (CoP) was measured on a force platform in standing position for 40 s under two sensorial and leg dominance conditions. Girls showed lower MVeloc (p 0.001) and Sway (p < 0.001) values than boys in both sensorial conditions (open and closed eyes). The highest values in all PC variables were observed with eyes closed in both genders (p < 0.001). Sway values were lower in boys combat-athletes compared to endurance athletes in two sensorial conditions and with non-dominant leg (p < 0.05). Young athletes in their teens enrolled in a Sport Technification Program have shown differences in PC when comparing different visual conditions, sport disciplines and gender. This study opens a window to a better understanding of the determinants of PC during single-leg stance as a critical element in the sport specialization of young athletes.Fisioterapi

Experimental resuts and simulation with TRNSYS of a 7.2 kWp grid-connected photovoltaic system

This paper presents a dynamic model and experimental results of a 7.2. kWp photovoltaic (PV) installation located at the Polytechnic University of Valencia (Spain). The modelling of the monocrystalline cells has been realised in TRNSYS and has been validated during an extensive experimental campaign from January 2001 to March 2003, using the data of a fully monitored PV field. The simulation results with TRNSYS provide an accurate prediction of the long-term performance. In addition to the dynamic models, algebraic methods such as the constant fill factor have also been applied.In the design of PV systems, there are several important uncertainties which have to be taken into account, such as the reduction of power with respect to the nominal power under Standard Test Conditions (STC), the choice of the meteorological database, and the models for the calculation of the radiation on tilted surface and of the cell temperature. These aspects are analyzed thoroughly in this paper, as well as the problems inherent to the PV power injection into the grid.Quesada, BR.; Sánchez, C.; Cañada, J.; Royo Pastor, R.; J. Payá (2011). Experimental resuts and simulation with TRNSYS of a 7.2 kWp grid-connected photovoltaic system. Applied Energy. 88:1772-1783. doi:10.1016/j.apenergy.2010.12.011S177217838

Humic-like substances from urban waste as auxiliaries for photo-Fenton treatment: a fluorescence EEM-PARAFAC study

[EN] In this work, analysis of excitation-emission-matrices (EEM) has been employed to gain further insight into the characterization of humic like substances (HLS) obtained from urban wastes (soluble bio-organic substances, SBOs). In particular, complexation of these substances with iron and changes along a photo-Fenton process have been studied. Recorded EEMs were decomposed by using parallel factor analysis (PARAFAC). Three fluorescent components were identified by PARAFAC modeling of the entire set of SBO solutions studied. The EEM peak locations (lambda(ex)/lambda(em)) of these components were 310-330 nm/400-420 nm (C1), 340-360 nm/450-500 nm (C2), and 285 nm/335-380 nm (C3). Slight variations of the maximum position of each component with the solution pH were observed. The interaction of SBO with Fe(III) was characterized by determining the stability constants of the components with Fe(III) at different pH values, which were in the order of magnitude of the ones reported for humic substances and reached their highest values at pH = 5. Photochemical experiments employing SBO and Fe(III), with and without H2O2, showed pH-dependent trends for the evolution of the modeled components, which exhibited a strong correlation with the efficiency reported for the photo-Fenton processes in the presence of SBO at different pH values.This work was supported by Generalitat Valenciana, Conselleria d'Ecuacio, Cultura i esport, Spain (GV/2015/074), Spanish Ministerio de Economia y Competitividad (CTQ2015-69832-C4-4-R) and by the Marie Sklodowska-Curie Research and Innovation Staff Exchange project funded by the European Commission H2020-MSCA-RISE-2014 (Project number: 645551). F. S. G. E. and L. C. are researchers from CONICET, Argentina.García-Ballesteros, S.; Constante, M.; Vicente Candela, R.; Mora Carbonell, M.; Amat Payá, AM.; Arques Sanz, A.; Carlos, L.... (2017). Humic-like substances from urban waste as auxiliaries for photo-Fenton treatment: a fluorescence EEM-PARAFAC study. Photochemical & Photobiological Sciences. 16:38-45. https://doi.org/10.1039/c6pp00236fS384516Malato, S., Fernández-Ibáñez, P., Maldonado, M. I., Blanco, J., & Gernjak, W. (2009). Decontamination and disinfection of water by solar photocatalysis: Recent overview and trends. Catalysis Today, 147(1), 1-59. doi:10.1016/j.cattod.2009.06.018WANG, J. L., & XU, L. J. (2012). Advanced Oxidation Processes for Wastewater Treatment: Formation of Hydroxyl Radical and Application. Critical Reviews in Environmental Science and Technology, 42(3), 251-325. doi:10.1080/10643389.2010.507698Pignatello, J. J., Oliveros, E., & MacKay, A. (2006). Advanced Oxidation Processes for Organic Contaminant Destruction Based on the Fenton Reaction and Related Chemistry. Critical Reviews in Environmental Science and Technology, 36(1), 1-84. doi:10.1080/10643380500326564Papoutsakis, S., Miralles-Cuevas, S., Oller, I., Garcia Sanchez, J. L., Pulgarin, C., & Malato, S. (2015). Microcontaminant degradation in municipal wastewater treatment plant secondary effluent by EDDS assisted photo-Fenton at near-neutral pH: An experimental design approach. Catalysis Today, 252, 61-69. doi:10.1016/j.cattod.2015.02.005Klamerth, N., Malato, S., Agüera, A., & Fernández-Alba, A. (2013). Photo-Fenton and modified photo-Fenton at neutral pH for the treatment of emerging contaminants in wastewater treatment plant effluents: A comparison. Water Research, 47(2), 833-840. doi:10.1016/j.watres.2012.11.008De Luca, A., Dantas, R. F., & Esplugas, S. (2015). Study of Fe(III)-NTA chelates stability for applicability in photo-Fenton at neutral pH. 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Degradation of 32 emergent contaminants by UV and neutral photo-fenton in domestic wastewater effluent previously treated by activated sludge. Water Research, 46(6), 1947-1957. doi:10.1016/j.watres.2012.01.014Gomis, J., Vercher, R. F., Amat, A. M., Mártire, D. O., González, M. C., Bianco Prevot, A., … Carlos, L. (2013). Application of soluble bio-organic substances (SBO) as photocatalysts for wastewater treatment: Sensitizing effect and photo-Fenton-like process. Catalysis Today, 209, 176-180. doi:10.1016/j.cattod.2012.08.036Gomis, J., Carlos, L., Prevot, A. B., Teixeira, A. C. S. C., Mora, M., Amat, A. M., … Arques, A. (2015). Bio-based substances from urban waste as auxiliaries for solar photo-Fenton treatment under mild conditions: Optimization of operational variables. Catalysis Today, 240, 39-45. doi:10.1016/j.cattod.2014.03.034Gomis, J., Bianco Prevot, A., Montoneri, E., González, M. C., Amat, A. M., Mártire, D. O., … Carlos, L. (2014). 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Fluorescence Inner-Filtering Correction for Determining the Humification Index of Dissolved Organic Matter. Environmental Science & Technology, 36(4), 742-746. doi:10.1021/es0155276Bahram, M., Bro, R., Stedmon, C., & Afkhami, A. (2006). Handling of Rayleigh and Raman scatter for PARAFAC modeling of fluorescence data using interpolation. Journal of Chemometrics, 20(3-4), 99-105. doi:10.1002/cem.978Ryan, D. K., & Weber, J. H. (1982). Fluorescence quenching titration for determination of complexing capacities and stability constants of fulvic acid. Analytical Chemistry, 54(6), 986-990. doi:10.1021/ac00243a033Yan, M., Fu, Q., Li, D., Gao, G., & Wang, D. (2013). Study of the pH influence on the optical properties of dissolved organic matter using fluorescence excitation–emission matrix and parallel factor analysis. Journal of Luminescence, 142, 103-109. doi:10.1016/j.jlumin.2013.02.052Dryer, D. J., Korshin, G. V., & Fabbricino, M. (2008). 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Hidratación del Al, Si, Mg y Ca en las mejoras de la interfaz árido-pasta en morteros con adicciones

[ESP] El objetivo del trabajo experimental es estudiar las mejoras de la interfaz árido-pasta en morteros con adicciones por la hidratación del Al, Si y Ca anhidro de la escoria. Al utilizar escoria como material cementante se recicla un residuo y se reduce el consumo de recursos naturales. Los resultados muestran que a la edad de 365 días, los morteros fabricados con sustitución del 50% de cemento por EGAH molida alcanzan una resistencia a compresión similar a la del mortero fabricado con el 100% del cemento. El consumo de hidróxido cálcico durante la hidratación de la escoria y la formación de gel mejoran las propiedades mecánicas de la interfaz escoria-pasta. [ENG] The aim of the experimental work is to study improvements in aggregate - paste interface mortars addictions hydration of Al, Si and Ca anhydrous slag. By using slag as a cementitious material is recycled waste and consumption of natural resources is reduced. The results show that at the age of 365 days, mortars made with replacement of 50% of cement by EGAH resistance reach similar to mortar made with 100% cement. Consumption of calcium hydroxide during the hydration of the EGAH and CSH improve the mechanical properties of the slag - paste interface.Escuela Técnica Superior de Ingeniería de Telecomunicación (ETSIT), Escuela Técnica Superior de Ingeniería Agronómica (ETSIA), Escuela Técnica Superior de Ingeniería Industrial (ETSII), Escuela Técnica Superior de Arquitectura y Edificación (ETSAE), Escuela Técnica Superior de Ingeniería de Caminos, Canales y Puertos y de Ingeniería de Minas (ETSICCPIM), Facultad de Ciencias de la Empresa (FCCE), Parque Tecnológico de Fuente Álamo (PTFA), Vicerrectorado de Estudiantes y Extensión de la UPCT, Vicerrectorado de Investigación e Innovación de la UPCT, y Vicerrectorado de Internacionalización y Cooperación al Desarrollo de la UPCT